CABLE LEAKAGE IMPACTS ON LTE PERFORMANCE. July 16, 2014

Transcription

1 CABLE LEAKAGE IMPACTS ON LTE PERFORMANCE July 16, 2014

2 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

3 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

4 HOW TO ASK A QUESTION Select the Q&A tab Type in your question and submit

5 NOW LET S GET STARTED CABLE LEAKAGE IMPACTS ON LTE PERFORMANCE July 16, 2014

6 Ken Couch 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.

7 AGENDA 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

8 DOWNLINK VS UPLINK Test 1: Downlink Testing Downlink Impact of Leakage on LTE Cell Phone Test 2: Uplink Testing Uplink Impact of Leakage on Cell Tower

9 DOWNLINK TEST SETUP CLG Control UE Control R&S CLG Cable Load Generator RF Combiner LG VL600 LTE UE R&S CMW Radio Communication Tester - BTS Simulator - R&S CMW-Z10 Shield Box

10 PHOTOS Test Participants R&S Shield Box & LTE UE R&S CLG and Communications Tester

11 SPECTRUM VIEW Cable QAMs Verizon Downlink Tested A B C D E D PSBB A B C C Public Safety A G PSNB B A DL B U L Public Safety G C D PSBB PSNB B B

12 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 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

13 TEST RESULTS Cell Signal Strength Error Correction QAM Power at Call drop uv/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% dbmv 663 Test 5 Weak 21.3% -38 dbmv 198 Test 1 RS-ERPE = dbm Test 2 RS-ERPE = dbm Test 3 RS-ERPE = -80 dbm Test 4 RS-ERPE = -100 dbm Test 5 (Worst Case) RS-ERPE = -100 dbm Mode = CQI Auto QAM, TBSI = Auto Mode = User Defined, 64 QAM 64 QAM, TBSI = 21, CR=.656 Mode = User Defined, 64 QAM 64 QAM, TBSI = 26, CR=.9411 Mode = User Defined, 64 QAM 64 QAM, TBSI = 25, CR=.81 Mode = User Defined, 64 QAM 64 QAM, TBSI = 24, CR=.787 QP dbmv CQI Data Rate QP CQI Data Rate QP CQI Data Rate QP CQI Data Rate QP CQI Data Rate BLER % % % -4 Connection Dropped Connection Dropped at -27 Connection Dropped at -38 dbmv Connection was unstable at start 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

14 SUMMARY OF TEST RESULTS uv/m 9,917 10,504 6, 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.

15 POLL QUESTION 1 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 Respond to the survey in the window on the right and click Submit

16 UPLINK TEST SETUP User Equipment Terminal Emulator Combiner Other (Terminated) Ericsson BTS PD2020 TX Combiner Splitter TRM USB PD2020 PD2020 (40.0 db) RX BandLuxe 525 (B13) 75Ω to 50Ω Continuous Data Stream ROHDE & SCHWARZ CLG ANRITSU MS2713E Testing took place at Ericsson Advanced Technology Lab

17 PHOTOS Test Participants Spectrum and R&S CLG Ericsson BTS Radio Ericsson BTS Digital

18 HOW DO WIRELESS PROVIDERS DETECT INTERFERENCE? 1. RSSI Noise floor Increases due to cumulative leakage 5 uv/m 2. LTE provider troubleshoots cell site 3. All leaks found are reported to cable operator 36 uv/m 501 uv/m 75 uv/m 55 uv/m Cell Tower 62 uv/m 75 uv/m 75 uv/m Uplink RSSI: Received Signal Strength Indicator 75 uv/m 120 uv/m 7 uv/m 51 uv/m

19 DOWNLINK TEST RESULTS Base Station Measurements: Radio Receive Interference vs Time Point of Noticeable Interference Leakage Power Level at Point of Interference = 5.12 uv/m This is the equivalent leakage level at the face of the antenna assuming a 12 dbi gain. Leak at Ant Through Put Time uv/m min max : : : : : : : : : : : :45

20 RESULTS VS CURRENT FCC LIMITS Leakage levels vs distance that will cause LTE Interference 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.

21 POLL QUESTION 2 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 Respond to the survey in the window on the right and click Submit

22 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 Proofof-Performance, LTE Interference and Power System Reliability session at SCTE Cable-Tec Expo 2014 Wednesday, Sept 24 at 4:00 PM MST

23 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.

24 HOW TO ASK A QUESTION Select the Q&A tab Type in your question and submit

25 THANK YOU TO OUR SPEAKER Ken Couch ComSonics

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