Embed Size (px)
Citation preview
CABLE LEAKAGE IMPACTS
ON LTE PERFORMANCE
July 16, 2014
SCTE LIVE LEARNING
• Monthly Professional Development service
• Generally “Hot Topics” or Topics of high interest
to the industry
• Vendor Agnostic – No product promotion
• Free to SCTE members
• Live sessions are recorded
– Members-only benefit
TODAY’S SESSION
• Approximately 50 minutes discussion
• 10 minute Q&A at the end, however..…
– Ask questions anytime throughout
the session
– Asking questions adds value and enhances
learning opportunity for you and others
HOW TO ASK A QUESTION
• Select the “Q&A” tab
• Type in your question and
submit
NOW LET’S GET STARTED…
CABLE LEAKAGE IMPACTS
ON LTE PERFORMANCE
July 16, 2014
VP of Marketing
ComSonics
• EE degree from University of Tennessee
• MBA degree from Fuqua School of Business, Duke University
• Worked in Telecommunications and Cable industry for 32 years in positions ranging from engineering, PLM, marketing, and sales.
Ken Couch
Review test setup and results of cable leakage
impacts on LTE performance
Downlink testing performed at Charter
Communications
Uplink testing performed at Advanced
Technology lab at Ericsson
This material is from efforts of the Network
Operations Subcommittee, part of the SCTE
Standards Program
AGENDA
DOWNLINK VS UPLINK
Test 1: Downlink Testing
Test 2: Uplink Testing
Impact of Leakage on LTE Cell Phone
Downlink
Uplink
Impact of Leakage on Cell Tower
DOWNLINK TEST SETUP
RF
Combiner
R&S CMW Radio Communication Tester
- BTS Simulator -R&S CMW-Z10 Shield Box
R&S CLG Cable Load Generator
LG VL600LTE UE
CLG Control
UE Control
PHOTOS
R&S CLG and Communications Tester
R&S Shield Box
& LTE UE
Test Participants
SPECTRUM VIEW
A B C D E AA B C C AD PSBB PSNBG
BB
Public Safety
C D PSBB PSNBG
BB
Public Safety
698 704 710 716 722 728 734 740 746 752 758 764 770 776 782 788 794 800 806
116 117 118
DL UL
114 115113
Cable QAMs
Verizon Downlink Tested
TEST METHODOLOGY
Start with low QAM Power levels and slowly increase power until LTE performance is effected
UE (cell phone) parameters monitored
1. Call Quality Index (CQI)
2. Data Throughput
Call Parameters Set Manually
1. QAM modulation set to 64
2. Code Rate or Amount of Error Correction between 5.9% to 40%
3. RS-EPRE: Energy per Resource Element (Cell Phone Signal Strength)
-80 to -100 dBm
TEST RESULTS
QP dBmV CQI Data Rate QP CQI Data Rate QP CQI Data Rate QP CQI Data Rate QP CQI Data Rate
-30 14 23.6 -10 14 25.46 -20 14 36.7 -30 13 27-28 -100 14 30.6
-10 14 23.6 -8 14 25.46 -15 14 36.7 -29.5 13 25 -50 14 30.6
-9 14 23.6 -7 14 25.46 -13 14 36.7 -29 13 24 -45 13 30.6 BLER
-8 14 23.6 -6 13-14 25.46 -10 14 33-35 -28.5 13 24 -40 13 27 11.0%
-7 14 23.6 -5.5 13 25.46 -9.5 14 32 -28 13 23 -39 13 25 17.6%
-5 14 15 -5 13 25.46 -9 14 30 -27.5 13 23 -38 13 20 30%
-4 Connection Dropped -4.5 13 25.46 -8.5 14 29.5 Connection Dropped at -27 Connection Dropped at -38 dBmV
-4 13 23 -8 14 27 Connection was unstable at start
-3.5 13 21 -7.5 14 5 to 8 TBSI too high for reliable results
Connection Dropped at -3.5 Connection Dropped at -7.5 Data Rate should have been 31.7 Mbps
BLER = 8.5% at -8, 13% at -7.5
Test 1
Mode = CQI
Auto QAM, TBSI = Auto
Test 2
Mode = User Defined, 64 QAM
64 QAM, TBSI = 21, CR=.656
RS-ERPE = -52.2 dBm RS-ERPE = -52.2 dBm
Test 5 (Worst Case)
RS-ERPE = -100 dBm
Mode = User Defined, 64 QAM
64 QAM, TBSI = 24, CR=.787
Test 3
Mode = User Defined, 64 QAM
64 QAM, TBSI = 26, CR=.9411
Test 4
Mode = User Defined, 64 QAM
64 QAM, TBSI = 25, CR=.81
RS-ERPE = -80 dBm RS-ERPE = -100 dBm
Cell Signal
Strength
Error
Correction
QAM Power
at Call dropuV/m
Test 1 Strong ≈40% -4.0 dBmV 9,917
Test 2 Strong 34% -3.5 dBmV 10,504
Test 3 Medium 5.9% -7.5 dBmV 6,628
Test 4 Weak 19% -27.5 dBmV 663
Test 5 Weak 21.3% -38 dBmV 198
SUMMARY OF TEST RESULTS
For Strong to Medium cell signal strengths (-52 to -80 dBm), it
takes a significant sized leak to impact the LTE
performance. The closer the user is to the leakage source, the more likely that
interference will occur
For Weak cell signal strengths (-100 dBm), large leaks can
impact LTE performance, again dependent on how close
the user is to a leak.
The impact of cable leakage on LTE cell phone service
is similar to a cliff effect – the call performance
deteriorates very quickly once it starts to drop.
The current FCC limit of 150 uV/m for leakage may be
reasonable to prevent a high percentage of possible
interference.
uV/m
9,917
10,504
6,628
663
198
Digital cable Leakage can potentially impact LTE downlink
performance under what conditions?
Strong leakage that is close to the cell tower
Strong leakage combined with too many cell phones in
a cell site
Strong leakage in areas with weak cellular strengths
Not enough error correction in the cell phones
POLL QUESTION 1
Respond to the survey in the window on the right and click “Submit”
UPLINK TEST SETUP
TRM
TX
RX
Terminal Emulator
USB
75Ω to 50Ω
(40.0 dB)
PD2020 PD2020
ROHDE &
SCHWARZ CLG
ANRITSU
MS2713E
Other (Terminated)
BandLuxe 525 (B13)
PD2020
Combiner Splitter
Combiner
Ericsson BTSUser Equipment
Testing took place at
Ericsson Advanced Technology Lab
Continuous
Data Stream
PHOTOS
Spectrum and R&S CLG Ericsson BTS Radio Ericsson BTS Digital
Test Participants
1. RSSI Noise floor Increases due
to cumulative leakage
2. LTE provider troubleshoots cell
site
3. All leaks found are reported to
cable operator
55 uV/m
5 uV/m
36 uV/m
75 uV/m
51 uV/m
62 uV/m
120 uV/m7 uV/m
501 uV/m
75 uV/m
75 uV/m
75 uV/m
Cell
Tower
Uplink RSSI: Received Signal
Strength Indicator
HOW DO WIRELESS PROVIDERS DETECT INTERFERENCE?
DOWNLINK TEST RESULTS
Point of Noticeable Interference
Leak at Ant Time
uV/m min max
0.1776 12.8 13.5 2:00
0.1776 12.8 13.5 2:15
0.1776 12.8 13.5 2:30
0.1776 12.8 13.5 2:45
0.2288 12.8 13.5 3:00
0.3503 12.8 13.5 3:15
0.6598 12.8 13.5 3:30
1.3014 12.8 13.5 3:45
2.5967 12.8 13.5 4:00
5.1217 10.5 11.8 4:15
10.3375 3.5 4.2 4:30
17.7589 0.3 1 4:45
Through Put
Leakage Power Level at Point of Interference = 5.12 uV/M
Base Station Measurements:Radio Receive Interference vs Time
This is the equivalent leakage level at the face of
the antenna assuming a 12 dBi gain.
RESULTS VS CURRENT FCC LIMITS
Interference Threshold Levels vs Distance
Current FCC Leakage Limit(150 uV/M)
The Current FCC Limit of 150 uV/m will provide sufficient protection beyond 600’ of the tower location.
Leakage levels vs distance that will cause LTE Interference
RSSI is used by the Wireless providers for what?
RSSI is used to measure and track cellular users in the
cell site
RSSI is used to measure the cumulative noise floor of
the cell site
RSSI indicates downlink performance issues
RSSI can locate cable leakage around the cell site
POLL QUESTION 2
Respond to the survey in the window on the right and click “Submit”
WHAT’S NEXT?
The test methodology and results are based on laboratory
environments.
How do these results compare to real-world environments?
Lab testing requires the use of assumptions for calculated results: • Free air space loss
• Antenna gain and tilt variance
• Single antenna vs. MiMo
• Line of sight vs terrain impacts
ComSonics has performed real-world testing of measuring cable leakage impacts on a live Verizon network (in cooperation with Verizon)
Further discussion will take place at the “Network Operations: FCC Proof-
of-Performance, LTE Interference and Power System Reliability” session
at SCTE Cable-Tec Expo 2014 – Wednesday, Sept 24 at 4:00 PM MST
SUMMARY
Digital Cable Interference impacts on the LTE downlink
has minimal potential for impact except for areas that
have very weak cellular strength.
Digital Cable Interference impacts on the LTE uplink can
be minimized if UHF leakage is controlled to current FCC
specifications.
HOW TO ASK A QUESTION
• Select the “Q&A” tab
• Type in your question and
submit
REMINDER
• This session has been recorded
• Will be available on SCTE’s Member’s Only Site within 2-3 days
• To access previously recorded sessions
login to:
www.scte.org – with your member ID#, then scroll to the bottom of the page and select
““““SCTE Live Learning Archives”””” for a menu of previously recorded Live Learning sessions
LIVELEARNING ARCHIVES
Free for SCTE Members
www.scte.org Under Resources/LiveLearning Archives
Topics include:
• Advanced Advertising
• Broadband Premises
• Business Services
• DOCSIS
• Emergency Alert System (EAS)
• Energy
• Ethernet
• Fiber Transport
• HFC Systems
• Home Networking
• IP
• OCAP
• PacketCable™
• Routing
• Service Management
• Standards
• Video
• VoIP
• Wireless Technology
NEXT MONTH
Register for the next
SCTE Live Learning webinar
BSS/OSSAugust 20, 2014
2:00 p.m. Eastern
www.scte.org
Under Professional Development/Live Learning
Available today at the conclusion of this presentation
LIVELEARNING REGISTRATION
Register for the
SCTE LiveLearning Series
www.scte.org
Under Professional Development/
LiveLearning WebinarsAvailable today at the conclusion of this presentation
Third Wednesday of the monthat 2 PM Eastern
