Testing passive networks in a distributed antenna system (DAS)€¦ · Testing passive networks in...
Transcript of Testing passive networks in a distributed antenna system (DAS)€¦ · Testing passive networks in...
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)
www.rohde-schwarz.com
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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