Passive DAS Hybrid DAS

Hybrid MIMO DAS branch dual-band example

Active DAS

Test bandsTest band 1698 MHz to 960 MHz

700 MHz band

850 MHz band

Test band 21695 MHz to 2700 MHz

1700 MHz band

1900 MHz band

2100 MHz band

2500 MHz band

Donor site

Multibandantennas

RF distributionnetwork

RF signalsourcesRF combining

Repeater or EDA

RRH

BBUBTS

Multiband antennas

RF signal sources

Fiber-optic distribution network

Headend unit

BBU

Multiband radio units

BTS

RRH

RF signal sources

POI trays

BTS

RRH

Multiband antennas

RF distribution network

RF signal sources

Fiber-optic distribution network

Headend unit

POI trays

Multiband radio units (FBDAs or RRUs)

BBU

A

B

S02

Fiberto/fromhub

S03

Ant 1AAnt 1B

Ant 2AAnt 2B

Ant 3AAnt 3B

Ant 4AAnt 4B

S01

S04

S05

S06

FBDA012

More information

https://www.rohde-schwarz.com/solutions/test-and-measurement/mobile-network-testing/ installation-and-maintenance/installation-and-maintenance_231988.html

White paper

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Testing passive networks in a distributed antenna system (DAS)

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Solutions from Rohde & Schwarz – your partner for testing passive networks in a distributed antenna system

R&S®ZPH series Cable and antenna analyzers

R&S®FSH series Handheld spectrum analyzers

R&S®FSH-Z29 Open/short/50 Ω load

R&S®ROMES4 drive test softwareWith R&S®TSMx walk test scanners

QualiPoc Android Handheld troubleshooter

PiMPro Tower Field PIM test set

Time sinks during testing

Test definitions

Simplifying DAS testing

No active elements in the antenna system

Simple to design Difficult to modify or adjust

RF transceivers near the antenna, fiber links

Easy to adjust and configure Expensive, with bulky equipment near the antenna

RF transceivers on each floor or section

Good price/performance ratio Easier to work with than a pure passive DAS

Better noise figure than a passive DAS

Rohde & Schwarz data sets simplify instrument setup

Rohde & Schwarz measurement re-porting software simplifies reporting tasks

Getting physical access to both ends of the cable

Load swapping – precision loads, precision shorts, passive intermodulation (PIM) loads and antennas all need to be connected at some point during the testing

Measurement naming issues – misnamed tests may effectively be lost, requiring rework

Improper test setup, requiring rework Submitting a failed trace as good, requiring rework

Failing tests at a later stage, requiring disassembly and retest of the passive network

What does return loss (RL) test? Return loss spots RF power loss due to reflections in

the antenna, cable, branch or system.

What does cable loss test? Cable loss measures the actual RF power loss in the cable

in specific bands, so it can be compared to the expected

power loss in these bands.

What does distance-to-fault test? Distance-to-fault (DTF) spots RF power loss caused by

reflections and shows how far down the cable, branch

or system each fault is.

What does passive intermodulation test? Passive intermodulation (PIM) tests check for signal distor-

tion in cables, antennas, branches and systems at higher

RF power levels.

What is a test band? A way to group multiple cellular bands together for

testing convenience.

SetupCreating a DAS test sequence: Define test bands Define tests and limits Create a test naming convention Set up quick names in the test equipment Test cables, antennas, branches and systems

Cable testWith a precision load, precision short, or a PIM

load on the end of each cable.

Tests commonly include: Band 1 and band 2 return loss Band 1 and band 2 cable loss Band 1 distance-to-fault Band 1 and band 2 PIM Seven tests per cable – 98 tests in this example

Cable and splitter assembly testWith precision loads, precision shorts, or PIM

loads in place of the antennas.

Tests commonly include: Band 1 and band 2 return loss Band 1 distance-to-fault Band 1 and band 2 PIM Five tests per branch in this example

Assembled cable, splitter and antenna assembly testTests commonly include: Band 1 and band 2 return loss Band 1 distance-to-fault Band 1 and 2 PIM Five tests per branch in this example

SetupTest naming convention example. 0: section zero of the stadium F012: FBDA 012 is the name of the FBDA at the base of this branch

A03B: the next device downstream of this cable is antenna 3B

B1: this test is done in test frequency band 1 DTFL: this is a distance-to-fault test with a precision load on the far end of the cable

CB: this is a cable test

Optional test for installed antennasTests commonly include: Band 1 and band 2 return loss Band 1 and band 2 PIM Four tests per antenna – 24 tests in this example

0_F012_A03B_B1_DTFL_CB

This simple 4 antenna hybrid MIMO branch may need 103 to 135 named tests, assuming two testing bands.

The Rohde & Schwarz quick name matrix simplifies test naming

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