Distributed Antenna Systems
Remade from scratch to the authoring rules: defaults asserted only where four of five projects would choose them, and scope boundaries matched to the neighboring standards
Showing changes from Rev 2
to Rev 3
in Distributed Antenna Systems.
---
title: Distributed Antenna Systems
category: Electrical
−toc_depth: 3
description: >
− When to use: design, supply, and installation of in-building Distributed Antenna
− Systems (DAS) for commercial cellular wireless coverage in large commercial,
− institutional, healthcare, hospitality, and mixed-use buildings. Covers passive,
− active (fiber-fed), hybrid, and digital DAS architectures; head-end equipment,
− remote units, antennas, coaxial and fiber distribution, splitters, combiners,
− amplifiers, and signal sources (off-air donor antennas, carrier base stations,
− small-cell head-ends); carrier-neutral / neutral-host designs serving multiple
− licensed carriers; 4G LTE and 5G NR sub-6 GHz bands (600 MHz to 3.7 GHz). Applies
− to buildings where the macro network alone cannot meet in-building signal targets
− (typically above ~50,000 sq ft, RF-attenuating construction, underground parking,
− large venues).
− Not intended for: public-safety responder radio enhancement / ERRCS / BDA
− (use [[sync/public-safety-radio-systems]]); structured cabling backbone, pathways,
− and TR/ER rooms (use [[sync/structured-cabling]]); telecommunications bonding and
− grounding busbars (use [[sync/telecommunications-bonding]]); Wi-Fi (IEEE 802.11)
− WLAN; carrier-owned, carrier-installed small cells with no building infrastructure;
− public address and paging distribution (use [[sync/public-address-and-paging]]).
+ When to use: In-building distributed antenna systems (DAS) that extend commercial cellular service into a building or a group of buildings: the signal source for each carrier, the head-end with its point of interface and combining, the coaxial and fiber distribution, the remote units, the indoor service antennas and radiating cable, the donor antenna where the source is off-air, power and standby power for the active equipment, remote monitoring, carrier coordination, acceptance testing, warranty, and spares. Covers passive, active, hybrid, and digital architectures, single-carrier and multi-carrier neutral-host service, and the licensed cellular bands from 600 MHz through the 3.7 GHz C-Band, on new construction and on existing buildings.
+
+ Not intended for: Public-safety responder radio coverage, meaning the emergency responder communication enhancement system, its UL 2524 bidirectional amplifier, its standby power, its supervision, and its acceptance by the fire code official ([[sync/public-safety-radio-systems]]), even where it shares pathways or passive components with the cellular DAS; the structured cabling backbone, the horizontal cabling, and their testing ([[sync/structured-cabling]]); the telecommunications rooms, equipment rooms, and the pathways that serve them ([[sync/telecommunications-rooms-and-pathways]]); the telecommunications bonding backbone and its busbars ([[sync/telecommunications-bonding]]); the conduit and cable tray the DAS cabling occupies ([[sync/raceways-and-conduit]], [[sync/cable-tray]]); the uninterruptible power supply as a product ([[sync/uninterruptible-power-supply-systems]]); public address and paging audio distribution ([[sync/public-address-and-paging]]); Wi-Fi wireless local area networks, which are active network equipment outside this standard; the carrier's own base station, small cell, and backhaul, which the carrier furnishes under its agreement with the Owner; and outdoor macro sites, towers, and rooftop carrier sites.
---
# Scope {toc}
−## This standard governs the design, supply, installation, and commissioning of in-building Distributed Antenna Systems (DAS) for commercial cellular wireless coverage. {note}
+## This standard covers the distributed antenna system from the point at which each carrier's signal enters the head-end to the indoor service antennas and radiating cable that deliver it, and, where the signal source is off-air, the donor antenna and the coaxial line that bring the macro signal into the building. {note}
−## A DAS captures or generates licensed cellular signal and redistributes it through a building over coaxial cable, fiber, or both so that mobile devices achieve usable signal in areas the macro-cellular network cannot reach. The system comprises a head-end (signal source plus combining and amplification), a distribution network, and distributed antennas. This standard covers passive, active fiber-fed, hybrid, and digital DAS architectures, neutral-host designs serving multiple carriers, and the 4G LTE and 5G NR sub-6 GHz bands from 600 MHz through 3.7 GHz. {note}
+## A distributed antenna system takes a licensed cellular signal from a base station, a small cell, or a donor antenna, conditions and combines it at a head-end, carries it through the building over coaxial cable, optical fiber, or both, and radiates it from antennas placed where the macro network does not reach, with the uplink from each handset carried back over the same path; the carriers that own the signal remain the operators of the service, and the building infrastructure is what this standard specifies. {note}
−## DAS is warranted where the macro-cellular network alone cannot deliver the required in-building signal level. {note}
+## Whether a building needs a DAS is settled by a survey of the macro signal inside the building as built or as modeled, not by its size alone; concrete cores, below-grade floors, metal-clad or low-emissivity envelopes, and large floor plates are the conditions under which the macro network fails indoors, and a building that already meets the design target on every floor has no use for one. {note}
−## The typical triggers are building area above approximately 50,000 sq ft, RF-attenuating construction (cast-in-place concrete, metal-clad or low-emissivity glazing), underground or structured parking, and large-venue or arena occupancies. Coverage need is established by survey of the as-built or modeled macro signal, not assumed; a building that already meets the design target on every floor does not require a DAS. {note}
+## Cellular DAS and public-safety responder radio coverage are separate systems with separate regulatory frameworks, separate amplifiers, and separate approving authorities: the cellular system operates under 47 CFR Part 20 with the consent of each carrier, and the responder system operates under the fire code with the acceptance of the fire code official. The two routinely share riser sleeves, cable tray, and sometimes antennas and coaxial runs. {note}
−## Cellular DAS and public-safety responder radio enhancement are distinct systems with separate regulatory frameworks, amplifiers, antennas, and approvals. {note}
+## Where a public-safety responder coverage system shares pathways, coaxial distribution, or antennas with the cellular DAS, this standard governs the cellular signal sources, the head-end, the combining, the cellular remote units, and the cellular acceptance test, and [[sync/public-safety-radio-systems]] governs the responder amplifier, its listing, its standby power, its supervision, and its acceptance; a shared passive component shall meet the more stringent requirement of the two standards.
−## Commercial cellular DAS operates under FCC Part 20 and requires carrier coordination agreements; public-safety responder radio enhancement (ERRCS / BDA) operates under FCC Part 90, is governed by IFC Section 510, NFPA 72 Chapter 24, and NFPA 1 Chapter 11, uses UL 2524-listed amplifiers, and is approved by the fire AHJ. The two systems frequently share physical pathways (conduit, cable tray, riser sleeves) but use separate amplifiers, antennas, and regulatory approvals. Public-safety responder coverage is specified under [[sync/public-safety-radio-systems]] and is outside this standard. {note}
+## Cellular signals shall not be combined onto a public-safety amplifier, and public-safety signals shall not be combined onto a cellular amplifier.
−## Cellular DAS and public-safety responder radio systems shall not be conflated or combined onto common amplifiers or antennas.
+## The following are outside this standard and are governed elsewhere. {note}
−## Scope boundary with adjacent telecommunications standards: structured cabling, telecommunications rooms, grounding busbars, and public address are specified under their respective standards. {note}
+- Public-safety responder radio coverage, governed by [[sync/public-safety-radio-systems]]
+- The structured cabling backbone, the horizontal cabling, and their testing and administration, governed by [[sync/structured-cabling]]
+- Telecommunications rooms, equipment rooms, entrance facilities, and the sleeves, trays, and supports that serve them, governed by [[sync/telecommunications-rooms-and-pathways]]
+- The telecommunications bonding backbone, the primary and secondary bonding busbars, and the bonding conductors to them, governed by [[sync/telecommunications-bonding]]
+- Conduit, raceway, and cable tray, governed by [[sync/raceways-and-conduit]] and [[sync/cable-tray]]
+- The uninterruptible power supply as a product, its topology, battery, and bypass, governed by [[sync/uninterruptible-power-supply-systems]]
+- The branch circuits and panelboards that feed the head-end and remote units, governed by [[sync/conductors-and-cables]] and [[sync/panelboards]]
+- The firestopping of DAS cable penetrations through rated assemblies, governed by [[sync/firestopping]]
+- Seismic bracing of the head-end racks and the remote units, governed by [[sync/vibration-isolation-and-seismic-restraint]]
+- The lightning protection system to which a rooftop donor antenna mast is bonded, governed by [[sync/lightning-protection]]
+- Public address and paging, governed by [[sync/public-address-and-paging]]
+- The carrier's base station, small cell, GPS receiver, and backhaul, which the carrier furnishes and installs under its agreement with the Owner
−## Backbone and horizontal structured cabling, telecommunications room provisioning, and cable-tray pathways are specified under [[sync/structured-cabling]]; telecommunications grounding busbars (TMGB/TGB) are specified under [[sync/telecommunications-bonding]]; public address and paging distribution is specified under [[sync/public-address-and-paging]]. Where this standard requires pathways, bonding, or fiber backbone, those elements are furnished under the referenced standards unless the Contract Documents assign them here. {note}
+## The service area of the DAS, including the floors, the parking levels, and any exterior area to be covered and any area to be excluded, shall be as indicated on [[drawing: the DAS coverage area plans]].
−## The Contractor shall coordinate the scope boundary between this standard and adjacent telecommunications standards before installation.
+## The licensed carriers to be served and the bands each carrier will deliver shall be as indicated on [[drawing: the DAS head-end block diagram]].
# Referenced Standards {toc}
## Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
−## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+## Where the contract documents, a carrier's written requirements, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard | Title |
|----------|-------|
−| FCC Part 20 | Commercial Mobile Radio Services (carrier coordination of signal boosters) |
−| NFPA 70 (NEC) | National Electrical Code, Article 800 (Communications Circuits) |
−| NFPA 70 (NEC) | National Electrical Code, Article 810 (Radio and Television Equipment) |
−| NFPA 70 (NEC) | National Electrical Code, Article 830 (Network-Powered Broadband Communications Systems) |
−| NFPA 70 (NEC) | National Electrical Code, Article 700 (Emergency Systems) |
−| NFPA 72 | National Fire Alarm and Signaling Code, Chapter 24 (Emergency Communications Systems) |
−| IFC | International Fire Code, Section 510 (Emergency Responder Radio Coverage) |
−| NFPA 1 | Fire Code, Chapter 11 (In-Building Public Safety Radio Enhancement) |
−| ANSI/TIA-568 | Commercial Building Telecommunications Cabling Standard (coaxial and fiber media, connectors) |
−| ANSI/TIA-607-C | Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises |
−| ANSI/TIA-4966 | Telecommunications Infrastructure Standard for Educational Facilities (DAS annex) |
−| IEEE 802.3bt | Ethernet Power over Ethernet Enhancements (Type 3/Type 4 PoE) |
−| UL 2524 | In-Building 2-Way Emergency Radio Communication Enhancement Systems (boundary reference) |
−| IBC | International Building Code (structural provisions for roof and wall antenna penetrations) |
+| 47 CFR Part 20 | Commercial Mobile Services (Section 20.21, Signal Boosters) |
+| 47 CFR Part 15 | Radio Frequency Devices |
+| NFPA 70 | National Electrical Code (Articles 300, 725, 770, 800, 805, and 810) |
+| UL 2043 | Fire Test for Heat and Visible Smoke Release for Discrete Products and Their Accessories Installed in Air-Handling Spaces |
+| UL 62368-1 | Audio/Video, Information and Communication Technology Equipment, Part 1: Safety Requirements |
+| UL 444 | Communications Cables |
+| UL 1651 | Optical Fiber Cable |
+| UL 50E | Enclosures for Electrical Equipment, Environmental Considerations |
+| NEMA 250 | Enclosures for Electrical Equipment (1000 Volts Maximum) |
+| ANSI/TIA-568.0 | Generic Telecommunications Cabling for Customer Premises |
+| ANSI/TIA-568.3 | Optical Fiber Cabling and Components Standard |
+| ANSI/TIA-569 | Telecommunications Pathways and Spaces |
+| ANSI/TIA-606 | Administration Standard for Telecommunications Infrastructure |
+| ANSI/TIA-607 | Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises |
+| ANSI/TIA-222 | Structural Standard for Antenna Supporting Structures, Antennas and Small Wind Turbine Support Structures |
+| IEC 62037 | Passive RF and Microwave Devices, Intermodulation Level Measurement |
+| IEEE 802.3 | Standard for Ethernet (Clause 145, Power over Ethernet) |
+| 3GPP TS 36.214 | Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Layer; Measurements |
+| 3GPP TS 38.215 | NR; Physical Layer Measurements |
+| NFPA 780 | Standard for the Installation of Lightning Protection Systems |
+| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13) |
# Submittals {toc}
## Action Submittals {toc}
−### The Contractor shall submit the following action submittals for review before fabrication, procurement, or installation:
−- RF design report including coverage prediction (heat map) per floor for each supported band, link-budget calculations, and noise-figure analysis.
−- System block diagram showing signal source, head-end, combiners, amplifiers, distribution medium, and every antenna with its zone assignment.
−- Product data for the head-end, remote units, antennas, splitters, combiners, amplifiers, and cabling, with frequency-band, gain, and composite-power ratings.
−- Riser diagram and floor plans showing antenna locations, cable routing, and head-end and remote-unit equipment locations.
−- Carrier coordination documentation: signed carrier agreement(s) or letter(s) of authorization for each licensed carrier the system will rebroadcast.
−- Cable and connector schedule listing coaxial type, fiber type and count, plenum/riser fire rating, and connector type for every run.
+### The Contractor shall submit the following for review and return before any DAS equipment or cable is procured:
+- The RF design report, giving the link budget for every band in each direction, the predicted downlink signal level and signal quality on every floor for every band as a color-scaled plot over the floor plan, the noise figure of the system at the base station interface, the uplink noise contribution at each carrier's receiver, and the assumptions made for wall, floor, and ceiling attenuation
+- A system block diagram showing every signal source, the point of interface for each carrier, the combining and splitting at the head-end, every remote unit and expansion unit, and every antenna with its zone
+- A riser diagram and floor plans showing the location of the head-end, every remote unit, every antenna, and every cable route, with the cable type and length of every run and the fiber strand count of every fiber route
+- Product data for the head-end units, remote units, antennas, radiating cable, splitters, couplers, combiners, attenuators, coaxial cable, connectors, fiber cable, and power supplies, giving for each active device its bands, gain, composite output power, noise figure, and ambient rating, and for each passive device its bands, insertion loss, return loss, and passive intermodulation rating
+- The head-end equipment room layout showing the racks, the carrier equipment space, the power circuits, the cooling, and the backhaul entry
+- The donor antenna mounting detail and the structural attachment calculation, where an off-air source is furnished
+- The carrier approval of the RF design, or the carrier's written acknowledgment that the design has been received for review, for every carrier to be served
+
```datasheet
−label: Action submittals required
+label: Action Submittals
type: checkbox
options:
− - RF design report and coverage prediction
− - System block diagram
− - Product data sheets
− - Riser diagram and floor plans
− - Carrier coordination documentation
− - Cable and connector schedule
−default: [RF design report and coverage prediction, System block diagram, Product data sheets, Riser diagram and floor plans, Carrier coordination documentation, Cable and connector schedule]
+ - "RF design report with coverage and signal quality plots"
+ - "System block diagram"
+ - "Riser diagram and floor plans with cable schedule"
+ - "Product data"
+ - "Head-end equipment room layout"
+ - "Donor antenna mounting detail and structural calculation"
+ - "Carrier approval or acknowledgment of the RF design"
+default:
+ - "RF design report with coverage and signal quality plots"
+ - "System block diagram"
+ - "Riser diagram and floor plans with cable schedule"
+ - "Product data"
+ - "Head-end equipment room layout"
+ - "Carrier approval or acknowledgment of the RF design"
```
+### No remote unit, antenna, or distribution cable shall be procured until the RF design report and the block diagram covering it have been reviewed and returned.
+
+### The RF design report is the document the whole system is built against and the one the carriers approve, so the coverage plots and the link budget are reviewed together; a plot that shows coverage the link budget cannot support is the submittal defect most often found. {note}
+
## Informational Submittals {toc}
−### The Contractor shall submit the following informational submittals:
−- Manufacturer certification or training records for the installing technicians on the specified DAS platform.
−- FCC registration or certification documentation for each amplifier and signal-booster device.
−- Network management system (NMS) configuration plan describing alarm points and BMS/SNMP integration.
+### The Contractor shall submit the following with or before the action submittals:
+- The qualifications of the RF designer and the record of comparable in-building systems designed
+- The manufacturer's certification of the installing and commissioning technicians on the DAS platform furnished
+- The FCC equipment authorization for every signal booster, remote unit, and head-end unit that transmits in a licensed band, identifying the band class and the industrial signal booster designation under 47 CFR 20.21
+- The written consent of each carrier whose signal the system retransmits, or the executed carrier agreement that contains it
+- The acceptance test procedure, naming the test instruments, the walk route or grid, the bands, and the pass criteria for each measured quantity
+- The monitoring configuration plan, listing every alarm point, its severity, and the destination it reports to
+
```datasheet
−label: Informational submittals required
+label: Informational Submittals
type: checkbox
options:
− - Installer certification / training records
− - FCC device registration / certification
− - NMS configuration plan
−default: [Installer certification / training records, FCC device registration / certification, NMS configuration plan]
+ - "RF designer qualifications"
+ - "Installer and commissioning technician certifications"
+ - "FCC equipment authorizations"
+ - "Carrier consent to retransmit"
+ - "Acceptance test procedure"
+ - "Monitoring configuration plan"
+default:
+ - "RF designer qualifications"
+ - "Installer and commissioning technician certifications"
+ - "FCC equipment authorizations"
+ - "Carrier consent to retransmit"
+ - "Acceptance test procedure"
+ - "Monitoring configuration plan"
```
## Closeout Submittals {toc}
−### The Contractor shall submit the following closeout submittals before final acceptance:
−- Commissioning test report with grid-test signal measurements per floor for every supported band.
−- Carrier acceptance test documentation for each rebroadcast carrier.
−- As-built drawings reflecting installed antenna locations, cable routing, and equipment.
−- Operation and maintenance manuals, NMS credentials, and warranty documents.
+### The Contractor shall submit the following before the system is accepted:
+- The acceptance test report, giving the measured downlink signal level and signal quality on every floor for every band as a color-scaled plot over the floor plan, the percentage of the service area meeting each criterion, every measured point that fails, and the instruments used with their calibration dates
+- The passive component test records, giving the sweep and passive intermodulation result of every coaxial run
+- The fiber test records for every fiber link furnished under this standard
+- Each carrier's acceptance of the system or its written statement of the items remaining before acceptance
+- The as-built riser diagram and floor plans showing every antenna, remote unit, and cable route as installed, with the label of every component
+- The final configuration of every head-end and remote unit, including the gain, the attenuation at each point of interface, and the alarm thresholds, exported from the management system
+- Operation and maintenance data, the management system credentials, and the warranty certificate identifying every active unit by serial number and the warranty commencement date
+- A signed receipt from the Owner for the spare parts delivered
+
```datasheet
−label: Closeout submittals required
+label: Closeout Submittals
type: checkbox
options:
− - Commissioning grid-test report
− - Carrier acceptance test documentation
− - As-built drawings
− - O&M manuals and warranty documents
−default: [Commissioning grid-test report, Carrier acceptance test documentation, As-built drawings, O&M manuals and warranty documents]
+ - "Acceptance test report with coverage and signal quality plots"
+ - "Passive component sweep and passive intermodulation records"
+ - "Fiber test records"
+ - "Carrier acceptance statements"
+ - "As-built riser diagram and floor plans"
+ - "Final head-end and remote unit configuration"
+ - "Operation and maintenance data, credentials, and warranty certificate"
+ - "Spare parts receipt"
+default:
+ - "Acceptance test report with coverage and signal quality plots"
+ - "Passive component sweep and passive intermodulation records"
+ - "Fiber test records"
+ - "Carrier acceptance statements"
+ - "As-built riser diagram and floor plans"
+ - "Final head-end and remote unit configuration"
+ - "Operation and maintenance data, credentials, and warranty certificate"
+ - "Spare parts receipt"
```
+### Record drawings and operation and maintenance data shall be assembled and delivered in the form required under [[sync/closeout-procedures]] and [[sync/operation-and-maintenance-data]], and the items listed above are the DAS content of that package.
+
# Quality Assurance {toc}
−## Carrier participation is a regulatory prerequisite, not a design preference, and shall be confirmed before infrastructure is procured. {note}
+## RF Design Responsibility {toc}
−## Under FCC Part 20, a commercial DAS that rebroadcasts a licensed carrier's signal requires that carrier's coordination agreement. Carrier base-station provisioning and neutral-host onboarding routinely take 6 to 18 months and sit on the project critical path. Specifying and installing distribution infrastructure without confirmed carrier participation produces a physically complete but non-functional system, which is among the most common and most expensive failures in DAS projects. {note}
+### The RF design of the system shall be prepared by the party indicated in the datasheet.
−### The Contractor shall not energize any amplifier that rebroadcasts a licensed carrier signal until a coordination agreement or letter of authorization from that carrier is in place.
+```datasheet
+label: RF Design Responsibility
+type: radio
+options:
+ - "Delegated design by the Contractor's RF designer to the performance criteria of this standard"
+ - "Design by the Engineer of Record, confirmed by the Contractor's shop drawings"
+ - "Design by the Owner's neutral-host operator, installed by the Contractor"
+default: "Delegated design by the Contractor's RF designer to the performance criteria of this standard"
+```
−### Installing technicians shall be manufacturer-certified on the specified DAS platform.
+### A delegated design puts the link budget, the antenna count, and the remote unit placement in the hands of the integrator who will be held to the acceptance test, which is how most in-building systems are procured; a design by the Engineer of Record fixes the antenna locations and the equipment before bid, so the bidders price the same system, at the cost of a design that the carriers have not yet seen and that the installer did not choose; a neutral-host operator's design comes with the operator's carrier agreements and its own equipment platform, and leaves the Contractor the installation and the building provisions. {note}
−### The RF design shall be prepared or reviewed by an engineer or RF designer with documented experience on in-building DAS of comparable size and architecture.
+### The RF design shall be prepared with predictive modeling software that computes propagation through a three-dimensional model of the building, using wall, floor, and glazing attenuation values taken from the construction documents or from measurement in the existing building.
−## Single-Source Responsibility {note}
+### The RF designer shall have designed not fewer than three in-building cellular systems of comparable area and architecture that have passed carrier acceptance, and the record of those systems shall be included in the informational submittals.
−## Fragmented active components from multiple vendors risk interoperability gaps in firmware, network management, and warranty coverage. Passive components (coaxial cable, splitters, antennas) do not share firmware or management interfaces and may be sourced from any manufacturer meeting the specified electrical and frequency ratings. {note}
+### Where the design is delegated, the Contractor shall revise the design at no additional cost to the Owner until the acceptance test criteria of this standard are met throughout the service area.
−### Active head-end, remote units, and distribution electronics shall be products of a single manufacturer's compatible platform.
+## Installer and Manufacturer Qualifications {toc}
−### Passive components (coaxial cable, splitters, antennas) may be sourced from any manufacturer provided they meet the specified electrical and frequency ratings.
+### The technicians who install, configure, and commission the active equipment shall hold a current certification from the manufacturer of the DAS platform furnished.
−# Environmental and Service Conditions {toc}
+### The technicians who terminate coaxial connectors shall have been trained by the connector manufacturer on the connector family furnished, and the technicians who terminate optical fiber shall be qualified as required under [[sync/structured-cabling]].
−## DAS equipment shall be rated for the temperature, humidity, and airflow conditions of its installed location.
+### The manufacturer of the active equipment shall have produced in-building cellular systems for not fewer than five years and shall maintain a technical support organization reachable by the Owner for the life of the warranty.
−## Head-end and remote-unit electronics are commonly located in telecommunications rooms, electrical rooms, or above accessible ceilings. Donor antennas and roof-mounted equipment are exposed to weather and solar load. Antennas and cabling installed in HVAC plenums must carry the appropriate plenum fire rating. The design shall confirm each device's rated environmental envelope against its actual location before submittal.
+### A passive intermodulation failure on a coaxial run is almost always a connector that was prepared or torqued by a hand that had not done that connector before, and the retest and rework it causes cost more than the training it replaces. {note}
+## Regulatory Compliance {toc}
+
+### Every head-end unit, remote unit, and amplifier that transmits in a licensed cellular band shall carry an FCC equipment authorization as an industrial signal booster under 47 CFR 20.21 for every band it transmits.
+
+### No amplifier that retransmits a carrier's signal shall be energized in a transmitting state until that carrier's written consent to retransmit has been received and submitted.
+
+### Digital equipment furnished under this standard shall comply with 47 CFR Part 15 for unintentional radiators.
+
+### Active equipment shall be listed to UL 62368-1 by a Nationally Recognized Testing Laboratory.
+
+### An industrial signal booster operates on the carrier's license, not on a license of its own, which is why the carrier's consent is the legal basis for turning it on; the consent is given to the Owner or the neutral-host operator, and the Contractor's obligation is to hold the transmitter off until the consent exists and to furnish the carrier the technical documents it asks for. {note}
+
+## Source Limitations {toc}
+
+### The head-end units, remote units, expansion units, and the management system shall be products of one manufacturer and one compatible platform.
+
+### Antennas, radiating cable, coaxial cable, connectors, splitters, couplers, combiners, and attenuators may be furnished from any manufacturer whose product meets the band, insertion loss, return loss, and passive intermodulation requirements of this standard.
+
+### Active units from one platform share firmware, a management system, a spare, and a warranty; passive components share none of those, and a passive component from a second maker that meets the ratings is interchangeable with the first. {note}
+
+# Carrier Coordination {toc}
+
+## Carrier Participation {toc}
+
+### Each carrier's participation is established by an agreement between the carrier and the Owner or the Owner's neutral-host operator, and that agreement, not this standard, fixes the carrier's capacity, its equipment, and its schedule. {note}
+
+### Carrier review of an in-building design and delivery of carrier equipment routinely take six to eighteen months from first contact, and the carrier's schedule is set by its own capital plan rather than by the construction schedule, so the building infrastructure is often complete and tested before any carrier signal is present. {note}
+
+### The Contractor shall submit the RF design to each carrier to be served, in the form that carrier requires, within fourteen days after the RF design report is returned reviewed.
+
+### The Contractor shall incorporate each carrier's design comments, shall resubmit the design to the Engineer where a comment changes a coverage plot, a remote unit, or an antenna, and shall track the status of every carrier approval in the progress reports.
+
+### Where a carrier has not approved the design or delivered its signal source by the date the building infrastructure is ready for test, the Contractor shall complete the passive and fiber tests and the system test on a test signal, and the acceptance test on that carrier's bands shall be performed when the carrier's signal is present.
+
+### The Contractor shall not be held in default of this standard for a carrier's failure to approve, deliver, or accept on the schedule, and shall not be relieved of the acceptance test criteria for a band once that carrier's signal is present.
+
+## Carrier Equipment Room Provisions {toc}
+
+### The head-end equipment room, the carrier equipment space within it, and the pathway from the entrance facility to the head-end shall be as indicated on [[drawing: the telecommunications plans]].
+
+### The provisions furnished under this contract for the carrier equipment shall be as indicated in the datasheet.
+
```datasheet
−label: Head-end equipment ambient temperature range
−type: range
−unit: °C
−min: -5
−max: 50
−step: 5
−setpoints: [-5, 0, 40, 50]
+label: Carrier Equipment Room Provisions
+type: checkbox
+options:
+ - "Floor space and equipment racks for each carrier's base station or small cell"
+ - "Dedicated branch circuits at each carrier's rack position"
+ - "Conduit or innerduct from the entrance facility to each carrier's rack position for backhaul"
+ - "Pathway and coaxial line from the roof for each carrier's GPS timing antenna"
+ - "Cooling for the heat release of the carrier equipment"
+default:
+ - "Floor space and equipment racks for each carrier's base station or small cell"
+ - "Dedicated branch circuits at each carrier's rack position"
+ - "Conduit or innerduct from the entrance facility to each carrier's rack position for backhaul"
```
+### A base station needs floor space, power, cooling, backhaul, and a GPS antenna with a view of the sky, and a carrier that arrives to find any of them missing leaves and reschedules; a small cell needs a shelf, one circuit, and an Ethernet backhaul, and a neutral-host operator furnishes some of these under its own agreement, which is why the list is selected per project. {note}
+
+### The number of carrier rack positions and the branch circuit rating at each shall be as indicated on [[drawing: the head-end equipment room layout]].
+
+### The room construction, lighting, door, and environmental conditioning of the head-end equipment room shall comply with [[sync/telecommunications-rooms-and-pathways]].
+
+## Carrier Approval and Acceptance {toc}
+
+### The Contractor shall furnish each carrier the measurements, the configuration data, and the site access it requires for its own acceptance testing, and shall correct every deficiency the carrier identifies that lies within the work of this standard.
+
+### A carrier's acceptance test confirms that the system does not harm the carrier's network and that the coverage meets the carrier's own criteria, and the carrier runs it with its own instruments and on its own schedule; the acceptance test of this standard is the Owner's test and is run whether or not a carrier has run its own. {note}
+
+### Where a carrier's written requirement for signal level, uplink noise, or isolation is more stringent than the datasheet value of this standard, the carrier's requirement shall govern for that carrier's bands.
+
+# Environmental and Service Conditions {toc}
+
+## Enclosure Rating {toc}
+
+### Remote units, expansion units, power supplies, and head-end enclosures furnished under this standard shall carry at least the enclosure rating indicated in the datasheet, rated under NEMA 250 or UL 50E.
+
```datasheet
−label: Head-end equipment location
−type: radio
+label: Minimum Enclosure Rating
+type: select
options:
− - Dedicated telecommunications room (TR)
− - Electrical / equipment room
− - Roof or penthouse (donor-antenna proximity)
−default: Dedicated telecommunications room (TR)
+ - "NEMA Type 1"
+ - "NEMA Type 12"
+ - "NEMA Type 3R"
+ - "NEMA Type 4"
+ - "NEMA Type 4X"
+default: "NEMA Type 1"
```
+### Nearly every remote unit sits above a ceiling, in a telecommunications room, or on a wall in a conditioned space, which is why Type 1 is the default; the clauses that follow raise the rating for the locations that need more, whatever the datasheet selects. Type 12 excludes dust and dripping non-corrosive liquid indoors; Type 3R excludes rain and sleet outdoors; Type 4 excludes hose-directed and wind-driven water; Type 4X adds corrosion resistance for salt air and chemical fumes. {note}
+
+### Remote units and power supplies installed outdoors, in an open parking structure, or in a loading dock open to the weather shall be rated NEMA Type 3R, Type 4, or Type 4X.
+
+### Remote units installed where they are subject to washdown or hose-directed water shall be rated NEMA Type 4 or Type 4X.
+
+### Remote units installed in a coastal location, a natatorium, or another location with salt or chemical vapor in the air shall be rated NEMA Type 4X.
+
+## Ambient Temperature {toc}
+
+### Remote units and expansion units installed indoors above a ceiling, in a shaft, or in an unconditioned interior space shall carry their full composite output power continuously at the design ambient temperature indicated in the datasheet.
+
```datasheet
−label: Plenum-rated components required (antennas and cabling in HVAC plenums)
−type: radio
−options:
− - 'Yes'
− - 'No'
−default: 'Yes'
+label: Indoor Unconditioned Design Ambient Temperature
+type: range
+unit: °C
+min: 40
+max: 55
+setpoints: [40, 45, 50, 55]
```
+### The space above a ceiling on a top floor under a dark roof, a mechanical shaft, and a return air plenum each run well above the room below them in summer, and a remote unit that throttles its output at its thermal limit does so in the afternoon, when the building is fullest. The value depends on the building and the climate, so the field carries no default. {note}
+
+### Remote units, power supplies, and donor antenna equipment installed outdoors or in a space that follows the outdoor temperature shall operate within their published performance between [[parameter: site-ambient-temperature-minimum]] and [[parameter: site-ambient-temperature-maximum]], including solar gain on an unshaded housing.
+
+### Head-end equipment shall be installed in a room conditioned to the equipment manufacturer's published operating range, and the heat release of the head-end equipment and the carrier equipment shall be reported to the Engineer for the cooling design of the room.
+
+## Air-Handling Spaces {toc}
+
+### Antennas, remote units, power supplies, and every other discrete product installed in a space used for environmental air shall be listed to UL 2043 or shall be installed in an enclosure that NFPA 70 300.22(C) permits in that space.
+
+### Coaxial cable installed in a space used for environmental air shall be plenum-rated and listed to UL 444 as Type CMP, and optical fiber cable in such a space shall be listed to UL 1651 as Type OFNP, in accordance with NFPA 70 Articles 770 and 805.
+
+### Cable installed in a riser shaft shall be listed as Type CMR or Type OFNR at minimum, and cable installed in a general-purpose space shall be listed as Type CM or Type OFN at minimum.
+
+## Seismic Restraint {toc}
+
+### Head-end racks, wall-mounted remote units, and antennas shall be anchored and braced for [[parameter: seismic-design-category]] in accordance with the seismic provisions of [[parameter: adopted-building-code]] and ASCE 7 Chapter 13, under [[sync/vibration-isolation-and-seismic-restraint]].
+
+### A ceiling-mounted antenna shall be supported independently of the ceiling grid where the ceiling grid is not rated to carry it, with a safety wire to structure.
+
# System Architecture {toc}
−## The DAS architecture shall be selected to match building size, floor-plate geometry, signal-source strategy, and budget.
+## Distribution Architecture {toc}
+### The system shall be of the distribution architecture indicated in the datasheet.
+
```datasheet
−label: DAS architecture
+label: Distribution Architecture
type: radio
options:
− - Passive (coaxial distribution from head-end amplifier)
− - Active (fiber-fed remote radio units)
− - Hybrid (active fiber backbone, passive coaxial zones)
− - Digital (baseband-over-fiber, CPRI/eCPRI)
−default: Hybrid (active fiber backbone, passive coaxial zones)
+ - "Passive, coaxial distribution from head-end amplifiers"
+ - "Active, analog radio over fiber to remote units"
+ - "Hybrid, fiber to zone remote units and coaxial within each zone"
+ - "Digital, digitized radio over fiber or Ethernet to remote units"
```
−## Passive DAS distributes signal entirely over coaxial cable from a head-end amplifier and suits buildings up to roughly 100,000 sq ft. Active fiber-fed DAS converts the signal to optical, distributes it over fiber to remote radio units, and suits buildings above 200,000 sq ft or multi-building campuses where coaxial loss budgets cannot close. Hybrid DAS runs an active fiber backbone to zone distribution units and then passive coaxial within each zone, balancing cost and reach for mid-rise buildings of roughly 100,000 to 500,000 sq ft. Digital DAS transports baseband over fiber (CPRI/eCPRI) to digital remote units and suits high-capacity venues and 5G NR deployments. {note}
+### A passive system carries RF on coaxial cable from a head-end amplifier through splitters to the antennas, has no powered device beyond the head-end, and loses signal with every foot of cable and every split, which limits it to the area one amplifier's power can reach; an active system converts each band to light at the head-end and back to RF at a remote unit near the antennas, so distance costs almost nothing and every remote unit is a powered device that needs a circuit, a fiber, and monitoring; a hybrid system runs fiber to a remote unit per zone and coaxial from there to a handful of antennas, trading some of the active system's remote unit count for some of the passive system's loss; a digital system carries the signal as data, so it is routed, split, and re-pointed by configuration rather than by cable, and it is the architecture that carries wide 5G channels and multiple-input multiple-output streams with the least degradation, at the highest equipment cost per antenna. The floor area, the number of carriers and bands, and whether capacity will later be moved between zones are what decide between them, so the field carries no default. {note}
−## Signal Source {toc}
+### Where a passive or hybrid system is selected, every coaxial run from the amplifier or zone remote unit to its antennas shall be verified against the link budget of the RF design, and no run shall be installed whose loss leaves an antenna below the power the link budget assigns it.
−### The signal source shall be selected per carrier and shall be confirmed compatible with the chosen architecture.
+### Where an active, hybrid, or digital system is selected, the system shall support the addition of remote units and the reassignment of capacity between zones through the management system without replacement of the head-end.
+### The capacity sectoring of the system, meaning which antennas and remote units are served by which sector of each carrier's signal source, shall be as indicated on [[drawing: the DAS head-end block diagram]].
+
+## Carrier Service Model {toc}
+
+### The system shall be configured for the carrier service model indicated in the datasheet.
+
```datasheet
−label: Signal source type
+label: Carrier Service Model
type: radio
options:
− - Off-air donor antenna (macro-network capture)
− - Carrier-provided base station (BTS)
− - Small-cell head-end (per carrier)
−default: Off-air donor antenna (macro-network capture)
+ - "Multi-carrier neutral host"
+ - "Single carrier"
+default: "Multi-carrier neutral host"
```
−### An off-air donor antenna captures the existing macro-network signal and is the lowest-cost source but depends on adequate outdoor signal and clear line-of-sight to the serving tower. A carrier-provided base station (BTS) delivers dedicated capacity independent of the macro network but requires carrier hardware, backhaul, and floor space. A small-cell head-end per carrier is the dominant 5G NR source and feeds passive or active distribution. The source choice drives capacity, latency, and the carrier-coordination path. {note}
+### A neutral-host system carries every participating carrier on one distribution plant, with each carrier's signal source combined at the head-end, so the Owner builds one system and each carrier joins by agreement; a single-carrier system carries one operator's bands only, is usually funded by that carrier for its own subscribers, and serves no one else in the building. An Owner-funded system in a multi-tenant building is a neutral-host system in almost every case, which is why it is the default. {note}
−### The donor antenna shall be installed with unobstructed line-of-sight to the serving macro cell.
+### Where a neutral-host system is selected, the head-end, the distribution, the remote units, and the antennas shall carry every band of every carrier shown on the head-end block diagram at the composite power the link budget requires for all of them together, and shall accept the addition of a carrier within the selected bands without replacement of the distribution or the antennas.
−### The donor antenna shall be structurally attached per NEC Article 810.
+### Where a neutral-host system is selected, the head-end shall provide a separate point of interface for each carrier, with the attenuation and the isolation between carriers set so that no carrier's signal source is exposed to another carrier's transmit power above the level that carrier permits.
−### Where an off-air donor antenna is used, antenna isolation shall exceed the amplifier gain by at least 15 dB to prevent oscillation.
+## Signal Source {toc}
−## Neutral-Host Configuration {toc}
+### Each carrier's signal source shall be of the type indicated in the datasheet, unless the head-end block diagram designates a different source for that carrier.
−### A neutral-host (multi-carrier) design shall share one distribution backbone among all served carriers, with each carrier providing its own signal source combined at the head-end.
−
```datasheet
−label: Carrier service model
+label: Signal Source
type: radio
options:
− - Neutral-host (multiple carriers, shared backbone)
− - Single-carrier dedicated
−default: Neutral-host (multiple carriers, shared backbone)
+ - "Off-air donor antenna and repeater"
+ - "Carrier base station at the head-end"
+ - "Carrier small cell at the head-end"
```
−### Neutral-host shared infrastructure is the dominant procurement model for new commercial construction: the building owner or a neutral-host operator deploys a single passive or active backbone, and each licensed carrier connects its own base station or small cell. Single-carrier dedicated systems are increasingly rare outside carrier-owned venues. The combining network at the head-end must accommodate the composite power and band set of every served carrier without intermodulation. {note}
+### An off-air source captures the carrier's macro signal with a rooftop donor antenna, amplifies it, and redistributes it; it needs no carrier equipment and no backhaul, costs the least, and gives the building only the capacity and quality the macro cell outside already has, which fails in the dense venue the DAS was built for. A carrier base station at the head-end adds dedicated capacity and the carrier's full band set, and needs the carrier to fund, deliver, and backhaul it, which is the long lead on the schedule. A carrier small cell at the head-end delivers dedicated capacity in a smaller package over an Ethernet or fiber backhaul, with fewer bands and less power than a base station, and is the source the carriers now offer most readily for mid-sized buildings. Which source a carrier will agree to is the carrier's decision, which is why the field carries no default. {note}
−### The number of licensed carriers served shall be specified, and the head-end combining network shall accommodate their composite power and band set without intermodulation.
+### Where an off-air source is furnished, the isolation between the donor antenna and every service antenna shall exceed the system gain in that band by not less than 15 dB, measured before the system is placed in service.
−```datasheet
−label: Number of licensed carriers served
−type: range
−unit: carriers
−min: 1
−max: 4
−step: 1
−setpoints: [1, 3, 4]
−```
+### Where an off-air source is furnished, the repeater shall include automatic gain control and oscillation detection that reduces gain or shuts the band down when the isolation margin is lost, and the event shall be reported as an alarm.
−# Frequency Bands and RF Performance {toc}
+### Where an off-air source is furnished, the donor signal level and quality at the donor antenna shall be measured and recorded for every band before the design is finalized, and a band whose donor signal falls below the level the repeater manufacturer publishes for its rated output shall be reported to the Engineer before equipment is procured.
−## The supported band set shall cover every frequency the served carriers and tenants require, confirmed before design.
+### A repeater amplifies whatever reaches its donor antenna, including the noise and the neighboring cells, so a weak or congested donor signal is redistributed as weak and congested service through the whole building, and no amount of gain inside the building improves it. {note}
+## Multiple-Input Multiple-Output Configuration {toc}
+
+### The system shall carry the multiple-input multiple-output configuration indicated in the datasheet on every band for which the serving carrier delivers it.
+
```datasheet
−label: Supported frequency bands
−type: checkbox
+label: MIMO Configuration
+type: radio
options:
− - 600 MHz (Band 71)
− - 700 MHz (Band 12/13/17)
− - 850 MHz (Band 5)
− - AWS 1700/2100 MHz (Band 4/66)
− - PCS 1900 MHz (Band 2/25)
− - 2500 MHz (Band 41)
− - C-Band 3.7 GHz NR (n77)
−default: [700 MHz (Band 12/13/17), 850 MHz (Band 5), AWS 1700/2100 MHz (Band 4/66), PCS 1900 MHz (Band 2/25), 2500 MHz (Band 41)]
+ - "Single stream"
+ - "2×2 MIMO"
+ - "4×4 MIMO"
```
+### A single-stream system carries one path per band and runs on one coaxial cable or one fiber channel and a single-port antenna; 2×2 MIMO carries two independent streams and doubles the data rate for a handset that supports it, at the cost of a second path through the distribution, a dual-port antenna, and roughly twice the remote unit radio count; 4×4 MIMO carries four streams and is what the carriers deliver on their mid-band 5G channels, and is carried in a digital architecture or with four-port antennas and four paths. The configuration cannot be upgraded later without replacing the antennas and the paths to them, so the decision is made for the bands the building will carry over its life. {note}
+
+### Every antenna, coaxial path, fiber channel, and remote unit radio shall provide the number of independent paths the selected configuration requires, end to end from the point of interface to the antenna.
+
+# Frequency Bands {toc}
+
+## The system shall carry the frequency bands indicated in the datasheet on every path from the point of interface to every antenna.
+
```datasheet
−label: 5G NR sub-6 GHz support required
−type: radio
+label: Frequency Bands Carried
+type: checkbox
options:
− - 'Yes'
− - 'No'
−default: 'No'
+ - "600 MHz (Band 71, n71)"
+ - "700 MHz (Bands 12, 13, 17, and 29)"
+ - "700 MHz Band 14 (FirstNet)"
+ - "850 MHz (Bands 5 and 26)"
+ - "1900 MHz PCS (Bands 2 and 25)"
+ - "1700/2100 MHz AWS (Bands 4 and 66, n66)"
+ - "2300 MHz WCS (Band 30)"
+ - "2500 MHz BRS/EBS (Band 41, n41)"
+ - "3.5 GHz CBRS (Band 48, n48)"
+ - "3.7 GHz C-Band (n77)"
+default:
+ - "700 MHz (Bands 12, 13, 17, and 29)"
+ - "850 MHz (Bands 5 and 26)"
+ - "1900 MHz PCS (Bands 2 and 25)"
+ - "1700/2100 MHz AWS (Bands 4 and 66, n66)"
```
−## Under-specifying bands is a common and costly error: a system built for only 700 MHz and 1900 MHz cannot serve a tenant who later needs AWS-3 or 5G NR C-Band, and adding bands after installation means replacing remote units and antennas. The common band set for large commercial and institutional buildings is 700 MHz (Band 12/13/17), 850 MHz (Band 5), AWS 1700/2100 MHz (Band 4/66), PCS 1900 MHz (Band 2/25), and 2500 MHz (Band 41), with 5G NR n77 (3.7 GHz C-Band) added where carriers require. {note}
+## The 700 MHz, 850 MHz, PCS, and AWS bands are the bands every national carrier operates and the ones every multi-carrier system has carried for a decade, which is why they are checked by default; 600 MHz and 2500 MHz are each one carrier's spectrum, Band 14 is the public-safety broadband network operated on a commercial carrier's equipment and is served by the cellular DAS rather than by the responder radio system, CBRS is shared spectrum a building can use for its own private network or that a carrier can bring, and C-Band is the mid-band 5G spectrum that carries the highest capacity and attenuates fastest through walls, so it needs more antennas than the low bands to reach the same area. A band left out at construction is added later only by replacing the remote units and, on a passive system, often the antennas and the splitters, so breadth here is bought once. {note}
−## Signal-Level Targets {toc}
+## Every passive component, including antennas, radiating cable, splitters, couplers, combiners, and connectors, shall be rated for continuous operation across every band checked, and the system shall be constructed so that an unchecked band within the passive components' rating can be added at the head-end without replacement of the distribution.
−### The design shall meet the specified in-building downlink signal target in general areas, with a defined edge-of-coverage minimum.
+## Each carrier's channel bandwidths and the uplink and downlink frequency pairs within each band shall be as that carrier states in its approval, and the Contractor shall configure the head-end filters and the remote unit sub-bands to them.
+# Coverage and Signal Quality {toc}
+
+## Downlink Design Target {toc}
+
+### The downlink reference signal received power, measured as defined in 3GPP TS 36.214 for LTE and 3GPP TS 38.215 for NR, shall be not less than the value indicated in the datasheet over the coverage area percentage selected under Coverage Area, for every band carried, with the handset at 1.5 m above the floor.
+
```datasheet
−label: Downlink design target (RSRP, general areas)
+label: Downlink Design Target, Reference Signal Received Power
type: range
unit: dBm
−min: -105
+min: -95
max: -75
−step: 5
−setpoints: [-90, -85, -75]
+setpoints: [-95, -90, -85, -80, -75]
+default: -85
```
+### A reference signal received power of -85 dBm is the design target most carriers publish for in-building service and the value a handset needs to hold a high-order modulation with margin for the body of the user and the walls between measurements, which is why it is the default; -75 dBm or -80 dBm is written for a stadium, a trading floor, or another venue where thousands of handsets contend for capacity and every decibel of margin is capacity; -90 dBm or -95 dBm is written for a parking structure or a warehouse where the service is voice and messaging and a lower target saves antennas. Each 5 dB of target roughly halves the area one antenna covers in the high bands. {note}
+
+### The design target shall be met with the remote unit composite output power at or below its rated value and with every band and every carrier carried simultaneously at its share of that power.
+
+### Where a carrier's approval states a design target for its bands more stringent than the datasheet value, that target shall govern for that carrier's bands as required under Carrier Approval and Acceptance.
+
+## Coverage Area {toc}
+
+### The downlink design target and the minimum signal quality shall each be met over not less than the percentage of the service area indicated in the datasheet, computed over the floor area of the service area shown on the coverage area plans.
+
```datasheet
−label: Edge-of-coverage downlink minimum (RSRP)
+label: Coverage Area Percentage
type: range
−unit: dBm
−min: -110
−max: -90
−step: 5
−setpoints: [-110, -105, -100, -90]
+unit: '%'
+min: 90
+max: 99
+setpoints: [90, 95, 98, 99]
+default: 95
```
−### The downlink target is expressed as RSRP for LTE and NR. A common general-area design target is -85 dBm; the default specified here is -90 dBm, with -105 dBm as the absolute edge-of-coverage minimum. The uplink link budget must close at the device transmit limit so that handsets at coverage edge can reach the source, typically requiring received uplink 10 to 15 dB above the noise floor at the base station. {note}
+### A 95 percent criterion is the one most carriers accept and most Owners write, and it leaves the stair landings, the elevator lobbies against the shaft, and the corners behind the mechanical room as the five percent that would each cost an antenna to reach; 98 or 99 percent is written for a hospital, a venue, or a tenant that will not accept a dead corner; 90 percent is written for a parking structure or a warehouse. The percentage multiplies the antenna count faster than the signal target does once it passes 95, because the last few percent are the hardest areas in the building. {note}
−### The system shall close the uplink link budget so that a device transmitting at its maximum power at the coverage edge is received above the source noise floor.
+### Areas within the service area for which a higher coverage percentage or a higher signal target applies, such as an executive floor, an operating suite, or a trading floor, shall be as indicated on [[drawing: the DAS coverage area plans]], and each shall be reported in the acceptance test as its own area.
−## Output Power and Gain {toc}
+### The coverage percentage shall be computed from the measured points within each floor of the service area, and a floor that fails the criterion shall fail the test regardless of the percentage achieved over the building as a whole.
−### Composite output power per remote unit and per amplifier shall be set within the specified envelope and within the device's rated linear range.
+## Signal Quality {toc}
−### Composite output power per active remote unit typically ranges from +20 dBm to +37 dBm (100 mW to 5 W) depending on zone size; a passive bi-directional amplifier head-end typically delivers a total composite output of +23 dBm to +33 dBm. Operating an amplifier beyond its rated composite power degrades the noise figure and generates intermodulation that interferes with both the DAS and the macro network. Gain shall be set so the link budget closes without exceeding the linear range.
+### The downlink signal-to-interference-plus-noise ratio shall be not less than the value indicated in the datasheet over the coverage area percentage, for every band carried.
```datasheet
−label: Composite output power per remote unit
+label: Minimum Downlink Signal-to-Interference-plus-Noise Ratio
type: range
+unit: dB
+min: 0
+max: 15
+setpoints: [0, 3, 5, 10, 15]
+```
+
+### Signal level alone does not make a connection usable: a handset that reads a strong reference signal from two cells at once, the DAS and the macro cell leaking through the glass, or two remote units overlapping, sees interference, and the signal-to-interference-plus-noise ratio is what measures that. A value of 10 dB or more is where the high-order modulations run; 5 dB is where voice and basic data hold; 0 dB is the edge of a usable connection. What the building needs depends on the macro signal that leaks into it and on the capacity the carriers deliver, so the field carries no default. {note}
+
+### Where a measured area fails the signal quality criterion because of macro signal entering through the building envelope, the Contractor shall raise the DAS signal in that area or re-aim the remote unit serving it until the criterion is met, and shall not rely on the carrier adjusting the macro cell.
+
+## Uplink Performance {toc}
+
+### The system shall be designed so that a handset transmitting at its maximum rated power at any point within the coverage area percentage is received at the carrier's signal source above the receiver sensitivity of that source with the margin the link budget states, for every band carried.
+
+### The uplink noise contribution of the system at each carrier's signal source receiver shall not exceed the limit that carrier states in its approval, and where the carrier states none, the system noise figure at the point of interface shall be as required under Noise Figure.
+
+### Each remote unit's uplink gain shall be set so that the sum of the uplink noise from every remote unit serving a sector, referred to the point of interface, stays within the carrier's limit, and the as-set values shall be recorded in the closeout configuration.
+
+### Every remote unit adds its own noise to the uplink whether or not a handset is talking through it, and the noise from all of them arrives at the base station together, so a system that passes its downlink test with forty remote units can still desensitize the carrier's receiver and fail carrier acceptance; the uplink is budgeted as a system, not a remote unit at a time. {note}
+
+## Signal Containment {toc}
+
+### The DAS signal measured outside the building envelope at grade and at the property line shall not exceed the level each carrier permits in its approval, so that the system does not capture handsets on the street or interfere with the carrier's macro cells.
+
+### Antennas within one antenna spacing of an exterior wall or of exterior glazing shall be oriented or attenuated so that the signal through the envelope is minimized, and the acceptance test shall include a measurement along the exterior of the building at grade.
+
+# Head-End Equipment {toc}
+
+## Point of Interface and Combining {toc}
+
+### The head-end shall provide a point of interface for each carrier's signal source, with the attenuation, the filtering, and the isolation needed to bring that source to the common level and to protect each carrier's equipment from every other carrier's transmit power.
+
+### The point of interface for each carrier shall include a directional coupler or a monitoring port at which the carrier's downlink level and the system's uplink noise can be measured without interrupting service.
+
+### Combining of carriers and bands shall be by low-loss, low-passive-intermodulation combiners rated for the composite power of every source combined, and the composite power at the output of the head-end combining shall be stated in the RF design report and shall not exceed the rating of any downstream component.
+
+### The attenuation at each point of interface shall be set to the value the RF design report states for that carrier and shall be recorded in the closeout configuration.
+
+### The point of interface is where the carrier's equipment and the Owner's system meet, and it is the demarcation at which responsibility changes hands; a level that drifts there is argued between the carrier and the integrator for months unless the as-set value is written down and a monitoring port lets either party measure it. {note}
+
+## Head-End Power {toc}
+
+### The head-end equipment shall be supplied from dedicated branch circuits as indicated on [[drawing: the head-end equipment room layout]], with no other load on any circuit serving the head-end.
+
+### Each circuit breaker serving the head-end or a remote unit power supply shall be identified at the panelboard as serving the DAS, with the legend "DAS: DO NOT DE-ENERGIZE WITHOUT NOTICE TO THE OWNER", in accordance with [[sync/electrical-identification]].
+
+### Each circuit breaker serving the head-end or a remote unit power supply shall be furnished with a handle lock-on device.
+
+### Where a surge protective device is furnished at the panelboard serving the head-end, it shall comply with [[sync/surge-protective-devices]], and the head-end power strips or power distribution units shall include surge protection listed for that purpose.
+
+## Remote Monitoring and Alarms {toc}
+
+### The system shall include a management system that monitors every head-end unit, remote unit, expansion unit, and power supply, that reports every alarm with the identity of the unit, the time, and the severity, and that holds the configuration of every unit.
+
+### The management system shall report alarms to the destinations indicated in the datasheet.
+
+```datasheet
+label: Alarm Reporting Interfaces
+type: checkbox
+options:
+ - "SNMP traps to the Owner's network monitoring system"
+ - "Dry contacts to the building management system"
+ - "Manufacturer's or neutral-host operator's remote monitoring service"
+ - "Email or text notification to the Owner's designated staff"
+default:
+ - "SNMP traps to the Owner's network monitoring system"
+```
+
+### A failed remote unit in a DAS is silent: the handsets in its zone drop to the macro signal or to nothing, and no one knows until a tenant complains. SNMP puts the alarm on the same screen as the Owner's switches and servers; dry contacts put it on the building management system where the operating staff already watch; a remote monitoring service puts it in front of the party who will dispatch the repair; notification by email or text reaches staff who watch none of those. The choice follows who in the building will act on the alarm. {note}
+
+### Alarm points shall include, at minimum, the loss of a carrier's downlink signal at the point of interface, the loss of fiber or coaxial link to any remote unit, a remote unit output power or gain fault, an over-temperature condition, an oscillation or isolation event, a power supply fault, and loss of utility power to any unit.
+
+### The management system shall be reachable by the Owner over the Owner's network and by the manufacturer or the neutral-host operator over a connection the Owner controls, and every account on it shall be turned over to the Owner at closeout.
+
+# Remote Units {toc}
+
+## Output Power {toc}
+
+### Each remote unit shall deliver, per band, the composite output power indicated in the datasheet while meeting the noise figure and the spectral emission limits of its FCC authorization.
+
+```datasheet
+label: Remote Unit Composite Output Power per Band
+type: range
unit: dBm
−min: 17
−max: 37
−step: 1
−setpoints: [17, 20, 33, 37]
+derived: "the RF design link budget for the zone each remote unit serves, with every carrier and band carried simultaneously"
+min: 20
+max: 43
+setpoints: [20, 24, 27, 30, 33, 37, 40, 43]
+default: derived
```
+### A low-power remote unit at 20 dBm to 27 dBm serves one or two antennas within a few meters of coaxial cable, which is the active architecture's usual case; a medium-power unit at 30 dBm to 33 dBm serves a hybrid zone of several antennas through a splitter; a high-power unit at 37 dBm to 43 dBm serves a large passive zone, a parking structure, or a radiating cable run. The power each zone needs follows from the link budget, the loss between the remote unit and its antennas, and the number of carriers and bands sharing that power, so the field is derived from the RF design and the engineer overrides it only to fix a class for the whole project. {note}
+
+### The composite output power of a remote unit shall be shared among every carrier and band it carries in the proportion the RF design states, and no single carrier's share shall be set so that another carrier's share falls below the level its link budget requires.
+
+### Remote units shall include automatic level control that holds the composite output at or below the rated value as the input level rises, and shall report an input overdrive as an alarm rather than clipping the output.
+
+## Noise Figure {toc}
+
+### The uplink noise figure of the system, measured from any antenna port to the point of interface with every remote unit in the sector connected, shall not exceed the value indicated in the datasheet.
+
```datasheet
−label: Amplifier noise figure (maximum)
+label: Maximum System Uplink Noise Figure
type: range
unit: dB
min: 3
−max: 9
−step: 0.5
−setpoints: [3, 5, 6]
+max: 8
+setpoints: [3, 4, 5, 6, 8]
```
−# Distribution Network {toc}
+### The noise figure fixes how faint a handset the base station can still hear through the DAS, and it rises with every remote unit added to a sector and with every decibel of passive loss ahead of the first amplifier. A carrier that states an uplink noise limit effectively sets this value; where it does not, the value depends on how many remote units share each sector, so the field carries no default. {note}
−## Coaxial Distribution {toc}
+## Remote Unit Power Method {toc}
−### Passive coaxial distribution shall use 50 Ω plenum-rated cable sized to the run length and signal budget.
+### Remote units and expansion units shall be powered by the method indicated in the datasheet.
−### Trunk runs use 50 Ω flexible coaxial cable with a nominal 0.4 in OD; drops of 30 ft or less may use 50 Ω flexible coaxial cable with a nominal 0.2 in OD. Passive trunk runs longer than approximately 150 ft exceed the loss budget and starve the downstream antennas of signal, which then forces additional amplifiers that were not in the original design. The design shall verify every passive run against the loss budget rather than assuming a fixed maximum.
−
```datasheet
−label: Trunk coaxial cable type
+label: Remote Unit Power Method
type: radio
options:
− - 50 Ω flexible coaxial, 0.4 in nominal OD
− - 50 Ω flexible coaxial, 0.6 in nominal OD
−default: 50 Ω flexible coaxial, 0.4 in nominal OD
+ - "Power over Ethernet from the head-end or an intermediate power sourcing equipment"
+ - "Centralized DC over a composite fiber and copper cable from the head-end"
+ - "Local branch circuit at each remote unit"
+ - "Local DC power supply in the nearest telecommunications room"
```
+### Power over Ethernet carries power and the digital signal on one cable from a power sourcing device, with the wattage that IEEE 802.3 Clause 145 permits per port and the 100 m reach of the cabling, so it suits a digital system with low-power remote units; centralized DC over a composite cable carries the fiber and the power conductors in one jacket to any distance the DC drop allows, with one power plant and one standby source at the head-end, and it is the usual method for a fiber-fed system with medium-power units; a local branch circuit at every remote unit gives each unit its own power with no distance limit, and puts a receptacle above every ceiling the remote units sit in and a circuit on the electrical drawings for each; a local DC supply in the telecommunications room serves the remote units on that floor from one power supply over low-voltage cable. The method sets the electrical scope, the standby power design, and the cable plant, so it is decided with the architecture. {note}
+
+### Where Power over Ethernet is selected, the power sourcing equipment shall be of the IEEE 802.3 Clause 145 type that delivers the power each remote unit draws at the end of the cabling furnished, and the cabling shall be of the category and construction the remote unit manufacturer publishes for that power level.
+
+### Where centralized DC or a local DC supply is selected, the power conductors shall be sized so that the voltage at the farthest remote unit at full load is within the unit's published input range, and the circuit shall comply with NFPA 70 Article 725 for its class.
+
+### Where a local branch circuit is selected, each remote unit shall be served by a receptacle within 6 ft of the unit on a circuit dedicated to DAS equipment and identified as required under Head-End Power, and the receptacle locations shall be as indicated on [[drawing: the electrical plans]].
+
+## Standby Power {toc}
+
+### The head-end equipment and the remote units shall continue to operate on standby power for not less than the duration indicated in the datasheet after loss of utility power.
+
```datasheet
−label: Maximum passive trunk run length
+label: Standby Power Runtime
type: range
−unit: ft
−min: 50
−max: 200
−step: 10
−setpoints: [120, 150, 200]
+unit: minutes
+min: 0
+max: 480
+setpoints: [0, 15, 30, 60, 120, 240, 480]
```
−### Coaxial cable installed in building risers and HVAC plenums shall carry the fire rating required by NEC Article 800 for its location.
+### A commercial cellular DAS carries no life-safety load and no code requires it to run through an outage, so many Owners furnish none and accept that cellular service in the building rides on the macro network during an outage; 15 to 30 minutes rides through utility switching and generator start; two to eight hours keeps the service up through an outage in a hospital, a hotel, or a venue whose occupants have no other telephone. The responder radio system, where one shares the infrastructure, carries its own code-required standby under [[sync/public-safety-radio-systems]], and that requirement is not met by the value selected here. {note}
−### Coaxial runs serving any public-safety overlay shall use 2-hour fire-rated cable where required by NFPA 72 and the AHJ.
+### Where a standby runtime greater than zero is selected, the standby source shall be either an uninterruptible power supply complying with [[sync/uninterruptible-power-supply-systems]], sized for the connected load of the head-end and of every remote unit powered from the head-end, or a connection to the building standby system, whichever is indicated on [[drawing: the electrical one-line diagram]].
−## Fiber Distribution {toc}
+### Where remote units are powered by local branch circuits and a standby runtime greater than zero is selected, the circuits serving the remote units shall be fed from the standby source as well as the head-end.
−### Active and digital DAS shall distribute over fiber sized to the run distance.
+# Antennas {toc}
−### Intra-building runs of 300 m or less may use OM3 or OM4 multimode fiber (50/125 µm); runs longer than 300 m or between buildings shall use OS2 single-mode fiber. Fiber backbone pathways from the telecommunications room to the head-end are frequently a scope gap between the low-voltage and IT contractors; the demarcation shall be stated explicitly in relation to [[sync/structured-cabling]].
+## Indoor Service Antennas {toc}
+### The location, type, and orientation of every indoor service antenna shall be as indicated on [[drawing: the DAS antenna plans]].
+
+### Indoor service antennas shall be rated for every band carried, shall have the number of ports the MIMO configuration requires, shall have a passive intermodulation rating not worse than the value required under Passive Components and Passive Intermodulation, and shall have a gain and a pattern that match the values the RF design assumed for them.
+
+### An omnidirectional ceiling antenna radiates evenly around it and serves an open floor plate from its center; a directional panel antenna radiates in one direction and serves a corridor, a perimeter zone, an atrium from its wall, or a parking deck from a column, and keeps the signal off the glass behind it; the RF design places each by the geometry of the space, and the plans show the result. {note}
+
+### An antenna may be installed within 5 ft of the location shown on the antenna plans to clear a light fixture, a diffuser, a sprinkler, or a structural member, and any relocation beyond 5 ft shall be re-predicted by the RF designer and submitted before installation.
+
+### Antennas shall be installed not less than 3 ft from a fire alarm notification appliance, a wireless access point, or another radiating device, unless the RF design documents a closer spacing.
+
+## Antenna Mounting and Appearance {toc}
+
+### Indoor service antennas in finished spaces shall be mounted as indicated in the datasheet.
+
```datasheet
−label: Fiber type for active / digital DAS
+label: Indoor Antenna Mounting
type: radio
options:
− - OM3 multimode (50/125 µm, ≤ 300 m)
− - OM4 multimode (50/125 µm, ≤ 300 m)
− - OS2 single-mode (> 300 m or inter-building)
−default: OM4 multimode (50/125 µm, ≤ 300 m)
+ - "Exposed, mounted on the finished ceiling"
+ - "Concealed above the ceiling"
+default: "Exposed, mounted on the finished ceiling"
```
−# Antennas {toc}
+### An exposed antenna radiates into the room with no loss between it and the handset and is a low-profile disk or dome a few inches across that reads, to most occupants, as a smoke detector; an antenna concealed above the ceiling radiates through the ceiling tile or gypsum board, loses roughly 2 dB through mineral fiber tile and 5 dB or more through gypsum board and the ductwork and conduit above it, and is placed where the ceiling plenum allows rather than where the design wants, so it takes more antennas to cover the same area and can be inspected only by lifting the ceiling. Exposed mounting is the default because it is what nearly every project does outside a space the architect has reserved; the exception is selected for that space. {note}
−## Antenna type, density, and placement shall be selected to achieve the signal target across each floor plate. {note}
+### Where antennas are concealed above the ceiling, the RF design shall include the measured or published attenuation of the ceiling construction in the link budget, and each concealed antenna shall be located so that it is accessible from a lay-in tile or an access panel.
−## Omnidirectional ceiling-mount patch antennas suit open floor plates; directional panel antennas suit corridors, perimeters, and long narrow spaces. On open plates an omnidirectional antenna covers roughly 2,500 to 5,000 sq ft, falling to 1,000 to 2,500 sq ft where cubicle partitions or concrete construction attenuate signal. The typical planning density is one antenna per 3,000 sq ft; the coverage prediction governs the final count and placement. {note}
+### Indoor service antennas in finished spaces shall have the housing finish indicated in the datasheet.
−## The primary antenna type shall be specified, selected to suit the coverage geometry of the floor plate it serves.
−
```datasheet
−label: Primary antenna type
+label: Indoor Antenna Housing Finish
type: radio
options:
− - Omnidirectional ceiling-mount patch
− - Directional panel
−default: Omnidirectional ceiling-mount patch
+ - "White housing"
+ - "Paintable housing, field-painted to match the adjacent ceiling"
+ - "Factory finish in a color selected by the Architect"
+default: "White housing"
```
−## The planning antenna density for open floor plates shall be specified, established by the coverage prediction for the actual construction and partition conditions.
+### A white housing matches a white ceiling and is the finish every antenna ships in; a paintable housing takes a field coat in a dark or colored ceiling, with a paint the manufacturer approves because a metallic or heavily filled paint attenuates the signal; a factory finish gives the Architect's color without a field coat, at a lead time and a premium per antenna. {note}
+### Where a paintable housing is selected, the paint shall be a non-metallic coating the antenna manufacturer approves, and the antenna gain after painting shall be verified on one sample per color before the remainder are painted.
+
+### Antennas in unfinished spaces, parking structures, mechanical spaces, and above-ceiling locations shall be furnished in the manufacturer's standard finish whatever the datasheet selects.
+
+## Radiating Cable {toc}
+
+### Radiating coaxial cable shall be installed where indicated on [[drawing: the DAS antenna plans]], and its type, coupling loss, and mounting height shall be as the RF design states.
+
+### Radiating cable is a coaxial cable with slots cut in its outer conductor so that it leaks signal along its whole length, and it is the antenna of choice in a tunnel, a parking ramp, an elevator hoistway, or a long corridor whose walls would block a point antenna every few meters; it is hung with standoffs that hold it a fixed distance from the wall or the deck, because the coupling loss the design assumed depends on that distance. {note}
+
+### Radiating cable shall be supported on non-metallic standoffs at the spacing and the distance from the mounting surface the cable manufacturer publishes, with no metallic object between the cable and the area it serves, and shall be terminated in a load or an antenna rated for the band set at its far end.
+
+## Donor Antenna {toc}
+
+### Where an off-air source is furnished, the donor antenna for each carrier shall be a directional antenna mounted on the roof or an exterior wall at the location indicated on [[drawing: the roof plan]], aimed at the serving macro cell the RF design identifies.
+
+### The donor antenna mount shall be designed for the wind load of the site in accordance with ANSI/TIA-222 and the structural provisions of [[parameter: adopted-building-code]], shall be attached to structure through a roof penetration or a non-penetrating ballasted mount that the roofing manufacturer accepts, and the attachment shall be shown in the action submittals.
+
+### The donor antenna coaxial line shall be grounded and protected at the building entrance in accordance with NFPA 70 Article 810, with a coaxial surge arrestor bonded to the building grounding electrode system under [[sync/grounding-and-bonding]].
+
+### Where the building has a lightning protection system, the donor antenna mast shall be bonded to it in accordance with NFPA 780 under [[sync/lightning-protection]].
+
+### The donor antenna shall be installed with its line of sight to the serving macro cell unobstructed by rooftop equipment, screens, or parapets, and the donor signal shall be re-measured at the installed location before the repeater is commissioned.
+
+# Coaxial Distribution {toc}
+
+## Coaxial Cable {toc}
+
+### Coaxial cable furnished under this standard shall be 50 Ω cable rated for every band carried, with a solid or corrugated copper or copper-clad aluminum outer conductor, a foam dielectric, and a jacket listed for the space in which it is installed as required under Air-Handling Spaces.
+
+### Trunk coaxial cable from a head-end amplifier or a remote unit to the first splitter and between splitters shall be of the nominal size indicated in the datasheet.
+
```datasheet
−label: Planning antenna density (open floor plate)
−type: range
−unit: sq ft per antenna
−min: 1000
−max: 5000
−step: 500
−setpoints: [3000, 3500]
+label: Trunk Coaxial Cable Size
+type: select
+options:
+ - "3/8 in."
+ - "1/2 in."
+ - "7/8 in."
+ - "1-1/4 in."
+default: "1/2 in."
```
−### Antenna locations are shown on the drawings and shall be field-coordinated with ceiling-mounted MEP, lighting, and fire-protection devices. [[drawing: antenna location plan]]
+### Half-inch cable loses roughly 2 dB per 100 ft at 700 MHz and 4 dB at 2 GHz, bends around a ceiling obstruction, and takes a connector a technician can make above a ceiling, which is why it is the trunk cable on most systems; 7/8 in. cable halves that loss for a long passive riser or a parking structure at the cost of a 10 in. bend radius and a connector that is made at a bench; 1-1/4 in. cable is run for the longest passive trunks where an amplifier cannot be placed; 3/8 in. cable is the trunk of a small passive system where the runs are short and the plenum is tight. A short drop from the last splitter to an antenna is run in smaller cable whatever the trunk size. {note}
−### Antennas serving 4×4 MIMO or beamformed 5G NR shall be MIMO-capable; single-port legacy antennas shall not be used for MIMO bands.
+### Drop cable from the last splitter or coupler to an antenna, not exceeding 30 ft in length, may be 1/4 in. or 3/8 in. coaxial cable or a factory-terminated jumper of the same impedance, provided the drop loss is included in the link budget.
−### Legacy DAS antennas are single-port and cannot carry 4×4 MIMO or beamforming, which 5G NR massive-MIMO sources require. Specifying single-port antennas on a system intended to carry 5G NR silently caps the system at SISO performance. Where any supported band uses MIMO, the remote units and antennas shall be MIMO-capable end to end.
+### Coaxial cable shall be installed with no bend tighter than the manufacturer's published minimum bend radius, shall be supported at the spacing the manufacturer publishes, and shall not be kinked, crushed, or pulled over an edge.
−# Power and Backup {toc}
+## Coaxial Connectors {toc}
−## The head-end and active remote units shall be served by dedicated, labeled, UPS-backed power.
+### Coaxial connectors on trunk cable, splitters, couplers, combiners, and remote unit ports shall be of the interface indicated in the datasheet.
```datasheet
−label: Head-end dedicated circuit rating
+label: Coaxial Connector Interface
type: radio
options:
− - 20 A, 120 V (single-carrier / passive)
− - 30 A, 120 V (multi-carrier active)
−default: 30 A, 120 V (multi-carrier active)
+ - "4.3-10"
+ - "N-type"
+ - "7/16 DIN"
```
+### The 4.3-10 interface was designed for low passive intermodulation, mates by hand or with a low torque, and is the interface the current remote units and low-intermodulation passive components ship with; the N-type interface is the one every technician knows and every test instrument carries, and holds its intermodulation rating only when torqued to specification with a wrench; the 7/16 DIN interface carries the highest power and the best intermodulation performance of the three on a large connector that suits a high-power head-end and a 7/8 in. trunk. A system is built on one interface, with adapters only at the test instrument, because every adapter is an intermodulation source. {note}
+
+### Connectors shall be of the type the cable manufacturer lists for the cable furnished, shall be installed with the manufacturer's preparation tools and torque, and shall not be field-adapted between interfaces except at a test instrument port.
+
+### Connectors installed outdoors, in a parking structure, or in any location subject to moisture shall be weatherproofed with a self-amalgamating tape and a cold-shrink or butyl wrap, or with a boot the connector manufacturer lists, after the connection has passed its sweep test.
+
+## Passive Components and Passive Intermodulation {toc}
+
+### Splitters, directional couplers, hybrid combiners, attenuators, and terminations shall be rated for every band carried, for the composite power at their location with margin, and for a passive intermodulation level not worse than the value indicated in the datasheet when measured with two 43 dBm carriers in accordance with IEC 62037.
+
```datasheet
−label: UPS backup runtime at full load
+label: Maximum Passive Intermodulation of Passive Components
type: range
−unit: hours
−min: 2
−max: 8
−step: 1
−setpoints: [2, 4, 8]
+unit: dBc
+min: -160
+max: -140
+setpoints: [-160, -155, -153, -150, -140]
+default: -150
```
−## Each head-end requires a dedicated 120 V circuit; a 20 A circuit is the minimum and a 30 A circuit is typical for multi-carrier active head-ends. The breaker shall be labeled "DAS HEAD-END - DO NOT DE-ENERGIZE." UPS backup runtime is a minimum of 2 hours at full load for commercial-cellular-only systems and a minimum of 4 hours for any system carrying a public-safety overlay, with NEC Article 700/701 applying where the overlay is a legally required system. {note}
+### Passive intermodulation is the signal a nonlinear joint, a loose connector, or a ferrous part generates when two strong downlink carriers mix in it, and the product lands in the uplink band where it is indistinguishable from a handset and raises the noise floor of the whole sector. A rating of -150 dBc at two 43 dBm carriers is the level every low-intermodulation DAS component is built and sold to, which is why it is the default; -153 dBc or -155 dBc is written for a high-power multi-carrier head-end where many carriers mix; -160 dBc is a laboratory-grade component; -140 dBc is accepted on a small single-carrier system where few carriers mix and the uplink has margin. {note}
−### The head-end breaker shall be labeled "DAS HEAD-END - DO NOT DE-ENERGIZE" at the serving panel.
+### Every passive component shall be of a construction with no ferrous material in the signal path, and every unused port on a splitter or coupler shall be terminated in a load of the same intermodulation rating.
−### Active remote units powered over Ethernet shall be served by IEEE 802.3bt (Type 3 or Type 4) PoE or a dedicated low-voltage circuit, coordinated with the electrical scope.
+### Every splitter, coupler, and combiner shall be mounted to structure or to a backboard, accessible from a lay-in ceiling or an access panel, and labeled as required under Identification.
+# Fiber Distribution {toc}
+
+## Fiber Type {toc}
+
+### Optical fiber furnished under this standard between the head-end and the remote units shall be of the type indicated in the datasheet.
+
```datasheet
−label: Active remote-unit power method
+label: DAS Fiber Type
type: radio
options:
− - PoE (IEEE 802.3bt Type 3, ≤ 60 W)
− - PoE (IEEE 802.3bt Type 4, ≤ 90 W)
− - Dedicated low-voltage circuit
−default: PoE (IEEE 802.3bt Type 4, ≤ 90 W)
+ - "OS2 singlemode"
+ - "OM4 multimode"
+ - "OM3 multimode"
+default: "OS2 singlemode"
```
−# Grounding and Bonding {toc}
+### Singlemode fiber carries the analog or digital optical signal of a DAS over any in-building or campus distance with no bandwidth penalty, and it is the fiber the active DAS platforms are designed for and ship their optics for, which is why it is the default; OM4 multimode serves a short run inside one building where the platform offers multimode optics, and OM3 serves a shorter one, and each is selected where an existing multimode backbone is to be reused rather than for a new installation. A platform whose optics are singlemode only cannot use a multimode strand at any length. {note}
−## DAS equipment shall be bonded to the telecommunications grounding system per ANSI/TIA-607-C. {note}
+### Fiber cable, connectors, and terminations shall comply with ANSI/TIA-568.3, shall be of the jacket listing required under Air-Handling Spaces, and shall be terminated in the connector type the DAS manufacturer specifies for its optical ports.
−## Head-end and remote-unit chassis shall be bonded to the telecommunications grounding busbar (TGB) or main busbar (TMGB) with conductors sized per ANSI/TIA-607-C. Inadequate or absent bonding produces ground-loop interference and can drive amplifier oscillation. The busbars themselves and the bonding backbone are furnished under [[sync/telecommunications-bonding]]; this standard requires only that DAS equipment connect to them. {note}
+### The fiber strand count on each route shall be as indicated on [[drawing: the DAS riser diagram]], and shall include not fewer than two spare strands on every route to a remote unit location.
−### Head-end and remote-unit chassis shall be bonded to the nearest TGB or TMGB with a conductor sized per ANSI/TIA-607-C.
+## Fiber Provision {toc}
−### Roof-mounted donor-antenna coaxial lines shall be grounded and protected per NEC Article 810.
+### The fiber between the head-end and the remote units shall be provided as indicated in the datasheet.
−# Network Management {toc}
+```datasheet
+label: DAS Fiber Provision
+type: radio
+options:
+ - "Dedicated fiber furnished and tested under this standard"
+ - "Strands assigned in the structured cabling backbone, furnished and tested under the structured cabling standard"
+```
−## The system shall include a network management system (NMS) with remote monitoring and alarm integration.
+### Dedicated fiber runs directly from the head-end to each remote unit, is owned by the DAS, is tested by the DAS installer, and leaves the structured cabling backbone untouched, at the cost of a second fiber plant in the risers; strands assigned in the structured cabling backbone use fiber that is already being run to every telecommunications room, with patching from the room to the remote unit, and make the DAS depend on the backbone's strand count, its patch panels, and its administration. Which is wanted depends on whether the backbone has the spare strands and whether the Owner wants the DAS separable from the data plant, so the field carries no default. {note}
−## Without remote monitoring, post-installation failures of a remote unit, fiber link, or amplifier go undetected until users complain. The NMS shall report device status and alarms over SNMP or the manufacturer's native protocol and shall forward critical alarms to the building management system. Alarm points shall include amplifier fault, oscillation, fiber-link loss, and loss of signal source.
+### Where strands in the structured cabling backbone are assigned, the strands shall be identified as DAS strands in the administration records under [[sync/structured-cabling]], the patch cords and the patching from the telecommunications room to the remote unit shall be furnished under this standard, and the demarcation between the two standards shall be the backbone patch panel in each telecommunications room.
−### The system shall provide an NMS that monitors every active device and reports faults over SNMP or a manufacturer-native protocol.
+### Where dedicated fiber is furnished, it shall be installed in the pathways indicated on [[drawing: the DAS riser diagram]], and shall be tested under this standard as required under Fiber Tests.
−### Critical alarms (amplifier fault, oscillation, fiber-link loss, loss of signal source) shall be forwarded to the building management system.
+# Testing {toc}
−# Testing and Commissioning {toc}
+## Passive Component Tests {toc}
−## The system shall be commissioned by grid-test signal measurement and accepted only against documented signal targets.
+### Every coaxial run from a head-end amplifier or remote unit port to an antenna port shall be swept over every band carried for return loss, insertion loss, and distance to fault before its antenna is connected, and the voltage standing wave ratio shall not exceed the value indicated in the datasheet at any frequency within the bands carried.
−## Without a defined grid-test protocol and acceptance criteria there is no contractual basis for system performance. The commissioning method follows the IFC 510 / NFPA 72 grid approach: each floor is divided into a measurement grid of at least 20 points, and every point must meet the minimum downlink signal threshold for every supported band. Critical areas - stairwells, elevators, and parking - are tested as 99% compliance zones. Each rebroadcast carrier additionally performs its own acceptance testing before the system is placed in service. {note}
−
−### Each floor shall be tested on a grid of at least 20 points per the IFC 510 / NFPA 72 method, and every point shall meet the minimum downlink signal threshold for every supported band.
−
```datasheet
−label: Grid-test points per floor
+label: Maximum Voltage Standing Wave Ratio of Installed Coaxial Runs
type: range
−unit: points
−min: 20
−max: 40
−step: 1
−setpoints: [20, 40]
+unit: ratio
+min: 1.2
+max: 1.5
+setpoints: [1.2, 1.3, 1.4, 1.5]
```
−### Critical areas (stairwells, elevators, parking) shall be tested as 99% compliance zones.
+### A ratio of 1.5:1 reflects about 4 percent of the power and is what a run with several splitters and connectors in it achieves without rework; 1.3:1 reflects under 2 percent and is written where the link budget is tight or the run feeds a high-power remote unit; 1.2:1 is a bench value a short factory-terminated run achieves. The ratio each project holds depends on how much margin its link budget carries, so the field carries no default. {note}
−### Each rebroadcast carrier shall perform and document acceptance testing before the system is placed in service.
+### Every coaxial run shall be tested for passive intermodulation with two 43 dBm carriers in accordance with IEC 62037 after its connectors are made and before its antenna is connected, with the far end terminated in a low-intermodulation load, and the measured level shall be not worse than the value required under Passive Components and Passive Intermodulation.
−### Uplink and downlink performance shall be verified at the source so that both link directions meet the design targets, not downlink alone.
+### A run that fails the sweep or the passive intermodulation test shall be corrected by remaking the failed connector or replacing the failed component and retested, and the record shall show both the failed and the passing result.
−# Delivery, Storage, and Handling {toc}
+## Fiber Tests {toc}
−## Equipment shall be delivered, stored, and handled to protect electronics and connectors from damage and contamination.
+### Every fiber link furnished under this standard shall be tested for insertion loss in both directions at 1310 nm and 1550 nm for singlemode fiber, or at 850 nm and 1300 nm for multimode fiber, in accordance with ANSI/TIA-568.3, and the measured loss shall not exceed the loss the DAS manufacturer publishes for the optical link.
−## Head-end and remote-unit electronics shall be kept in their original packaging, in a dry conditioned space, until installation. Coaxial cable ends and fiber connectors shall be capped to keep dust and moisture out, and fiber shall not be bent below its minimum bend radius at any point during pulling or storage. {note}
+### Every fiber link longer than 300 m shall also be characterized by optical time-domain reflectometer in both directions, and the trace shall be included in the fiber test records.
−### Active electronics shall be stored in original packaging in a dry, conditioned space until installed.
+### Every fiber connector end face shall be inspected and cleaned before mating, and a connector that shows a scratch or contamination in the core zone shall be re-terminated.
−### Coaxial and fiber connectors shall be capped until termination.
+## Coverage Acceptance Test {toc}
−### Fiber bend radius shall not be violated during pulling or storage.
+### After every carrier's signal source is connected and every remote unit is commissioned, the Contractor shall measure the downlink reference signal received power and the signal-to-interference-plus-noise ratio throughout the service area on every band carried by the method indicated in the datasheet, and shall compute the coverage percentage achieved against the criteria of Coverage and Signal Quality.
−# Warranty {toc}
+```datasheet
+label: Coverage Acceptance Test Method
+type: radio
+options:
+ - "Continuous walk test with a calibrated scanning receiver logging against the floor plan"
+ - "Grid test at fixed points with a calibrated scanning receiver, not fewer than 20 points per floor"
+default: "Continuous walk test with a calibrated scanning receiver logging against the floor plan"
+```
−## The Contractor shall provide a manufacturer warranty on equipment and a separate workmanship warranty on the installation.
+### A walk test logs a reading every second or every meter along a route that covers every corridor and room, and produces a plot that shows the signal everywhere a person goes, which is what the carriers' own acceptance tests do and why it is the default; a grid test divides each floor into equal cells and measures at the center of each, which produces a number per cell that is compared to the criterion and is the method the fire code uses for responder coverage. The grid test is selected where the Owner wants a result in the same form as the responder radio test, or where the service area is a parking structure the walk route cannot cover evenly. {note}
−## The manufacturer warranty covers the head-end, remote units, and active distribution electronics for the specified term; the workmanship warranty covers cabling, terminations, and installation labor. Because firmware and carrier configurations evolve, the warranty period and any included firmware updates shall be stated explicitly.
+### The scanning receiver used for the acceptance test shall be calibrated within the twelve months preceding the test, shall measure the reference signal received power as defined in 3GPP TS 36.214 or TS 38.215 rather than a handset's displayed value, and shall be carried at 1.5 m above the floor.
−### The Contractor shall provide a manufacturer equipment warranty of not less than the period selected below from the date of final acceptance.
+### The acceptance test shall be performed on every floor of the service area, in every stair, elevator lobby, and parking level within the service area, and along the exterior of the building at grade as required under Signal Containment.
+### Where the test is performed before every carrier's signal source is present, it shall be performed on the bands present, and shall be repeated on each remaining band within fourteen days after that carrier's source is connected.
+
+### Where a floor or an area fails a criterion, the Contractor shall correct the system and retest that floor or area, and the acceptance test report shall show both the failed and the passing result.
+
+### An uplink test shall be performed on every band at not fewer than five points per floor at the edge of the coverage area, with a handset or a test transmitter at its maximum power, and the received level and quality at the carrier's signal source or the system's monitoring port shall be recorded.
+
+## Test Witnessing and Retests {toc}
+
+### Witnessing of the coverage acceptance test shall be as indicated in the datasheet.
+
```datasheet
−label: Manufacturer equipment warranty period
+label: Coverage Acceptance Test Witnessing
type: radio
options:
− - 1 year
− - 2 years
− - 3 years
− - 5 years
−default: 2 years
+ - "Witnessed by the Owner's representative or the Engineer"
+ - "Certified test report without witnessing"
```
−### The Contractor shall provide a workmanship warranty of not less than one year on cabling, terminations, and installation labor.
+### A witnessed test lets the Owner's representative see the route walked, the instrument used, and the readings taken, and commits that person to a day or more on site for a large building; a certified report records the same results without the attendance and leaves any question about the route or the instrument to be settled from the logged data. Which the Owner wants depends on whether it will rely on the report to settle a dispute with a tenant or a carrier later. {note}
−# Spare Parts {toc}
+### Where witnessing is selected, the Contractor shall give not less than ten days' notice of the test, and the test shall not proceed without the witness unless the witness waives attendance in writing.
−## The Contractor shall furnish spare components sufficient to restore service after a single device failure.
+### The cost of repeating any test under this standard after a failure, including the witness's time for a witnessed retest, shall be borne by the Contractor.
−## At a minimum the owner should receive one spare of each active remote-unit type and a stock of antennas, connectors, and patch cords proportional to the installed quantity, so that a failed device can be replaced without waiting on procurement. Carrier-furnished base-station hardware is excluded from this spare-parts requirement. {note}
+# Installation {toc}
−### The Contractor shall furnish at least one spare of each active remote-unit type used in the system.
+## Cable Installation {toc}
+### Coaxial and fiber cable shall be installed in the pathways indicated on [[drawing: the DAS riser diagram]], in conduit, cable tray, or J-hooks furnished under [[sync/raceways-and-conduit]], [[sync/cable-tray]], and [[sync/telecommunications-rooms-and-pathways]], and shall not be laid on the ceiling, on ductwork, or on another system's cable.
+
+### DAS cable shall be separated from power conductors in accordance with NFPA 70 Articles 770 and 805, and from fluorescent and LED fixtures and their drivers by not less than 12 in. except where crossing at a right angle.
+
+### Every penetration of a fire-resistance-rated wall, floor, or smoke barrier by DAS cable shall be firestopped under [[sync/firestopping]] with a listed system for the cable type and the assembly.
+
+### Cable slack of not less than 3 ft shall be left at every antenna and every remote unit, coiled to not less than the minimum bend radius and secured.
+
+## Bonding {toc}
+
+### The chassis of every head-end unit, remote unit, expansion unit, and power supply, and every metallic coaxial cable shield at its entry to a telecommunications room, shall be bonded to the nearest telecommunications bonding busbar with a conductor sized in accordance with ANSI/TIA-607, and the busbars and the bonding backbone shall be those furnished under [[sync/telecommunications-bonding]].
+
+### An unbonded remote unit chassis sits at whatever potential its coaxial shield and its power cord give it, and the current that flows between them when they disagree is heard in the uplink as noise and seen in the management system as an intermittent fault; the bond is the first thing checked when a remote unit alarms and the last thing an installer thinks of. {note}
+
+### Where a remote unit is installed where no telecommunications bonding busbar is within reach of a bonding conductor of the length ANSI/TIA-607 permits, the Contractor shall report the location to the Engineer and shall bond the unit as the Engineer directs.
+
+## Identification {toc}
+
+### Every antenna, remote unit, expansion unit, splitter, coupler, combiner, and power supply, and both ends of every coaxial and fiber cable, shall be labeled with a unique identifier in the administration scheme of ANSI/TIA-606 as applied under [[sync/structured-cabling]], and the identifier shall match the as-built drawings and the management system.
+
+### Labels on antennas in finished spaces shall be placed on the face of the antenna that is concealed in service or inside the ceiling adjacent to it, so that no label is visible from the room.
+
+### Each remote unit and head-end unit shall carry a label stating that it is part of the DAS and giving the Owner's contact for service.
+
+### Equipment nameplates and circuit identification at the panelboards shall comply with [[sync/electrical-identification]].
+
+## Head-End and Remote Unit Mounting {toc}
+
+### Head-end equipment shall be mounted in equipment racks or wall-mounted enclosures in the head-end equipment room as indicated on [[drawing: the head-end equipment room layout]], with the clearances the manufacturer publishes for airflow and service.
+
+### Remote units shall be mounted to structure or to a backboard at the locations indicated on [[drawing: the DAS riser diagram]], with the manufacturer's published clearance for airflow, accessible from a lay-in ceiling, an access panel, or the floor without a lift where the location permits, and oriented so that the status indicators are visible to a technician at the unit.
+
+### A remote unit shall not be mounted on a ceiling tile, on ductwork, on a pipe, or above a hard ceiling with no access panel.
+
+# Delivery, Storage, and Handling {toc}
+
+## Active equipment shall be delivered in the manufacturer's original packaging with its serial number visible, and shall be stored indoors in a dry conditioned space within the manufacturer's published storage temperature range until installed.
+
+## Coaxial cable shall be delivered on reels with both ends capped, shall be stored upright on the reel, and shall be paid off the reel rather than pulled from a coil.
+
+## Fiber cable and fiber connector ends shall be capped until termination, and fiber shall not be bent below its minimum bend radius or loaded beyond its rated pulling tension at any point during handling.
+
+## Antennas shall be stored in their packaging until the day of installation, and an antenna whose radome is cracked or whose connector is damaged shall not be installed.
+
+## A coaxial cable that was kinked on a reel or dragged over a slab edge sweeps clean and fails its passive intermodulation test, and the fault is found only by replacing the run, so the cable is protected from the day it arrives rather than tested into compliance. {note}
+
+# Warranty {toc}
+
+## The active equipment, the antennas, the passive components, and the installation shall be warranted against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of system acceptance.
+
```datasheet
−label: Spare antennas furnished (percent of installed quantity)
+label: Equipment and Installation Warranty Period
type: range
+unit: years
+min: 1
+max: 5
+setpoints: [1, 2, 3, 5]
+```
+
+## A one-year term is the manufacturer's standard on most active DAS equipment and costs nothing beyond the purchase; a two-year or three-year term is bought as an extension and covers the period over which infant failures of remote units and power supplies show themselves; a five-year term is bought where the Owner wants the equipment covered until the first carrier technology change is likely to replace it. The term the Owner wants depends on who will maintain the system after the warranty ends, so the field carries no default. {note}
+
+## The warranty shall cover repair or replacement of the failed unit, antenna, or component, the labor to replace it, the reconfiguration of the replacement, and the retest of the affected coverage area.
+
+## Where a unit is repaired or replaced under warranty, the repaired or replaced unit shall carry a new warranty of the same term from the date of the repair, or the remainder of the original term, whichever ends later.
+
+## During the warranty period the Contractor shall furnish and install the firmware updates the manufacturer releases for the platform, and shall update the management system to match, at no additional cost to the Owner.
+
+## The warranty shall not cover a change in a carrier's signal source, band plan, or channel configuration, which is the carrier's work under its agreement with the Owner; the Contractor's warranty obligation on such a change is limited to reconfiguring the system to the new inputs at the Owner's request and expense.
+
+# Spare Parts {toc}
+
+## The Contractor shall deliver not fewer than one spare remote unit and one spare power supply of each type installed, matching the installed units in model, band set, and firmware, at system acceptance.
+
+## The Contractor shall deliver spare indoor service antennas of each type installed in the quantity indicated in the datasheet, as a percentage of the installed quantity of that type, with not fewer than one of each type.
+
+```datasheet
+label: Spare Indoor Antennas
+type: range
unit: '%'
−min: 2
+min: 0
max: 10
−step: 1
−setpoints: [2, 5, 10]
+setpoints: [0, 2, 5, 10]
```
−### The Contractor shall furnish spare connectors and patch cords proportional to the installed quantity.
+## A spare remote unit lets the Owner restore a zone the day a unit fails rather than the week the manufacturer ships one, and a spare antenna replaces the one a ceiling contractor breaks; the antenna quantity a project wants depends on how much ceiling work it expects over the life of the system, so the field carries no default. {note}
+
+## The Contractor shall deliver two spare factory-terminated coaxial jumpers of each length and connector interface installed, and one spare fiber patch cord of each type and length installed.
+
+## Spare parts shall be turned over against a written inventory signed by the Owner's representative, and the inventory shall be included in the closeout submittals.