DTT Receiver Performance and LTE Compatibility

Transcription

1 DTT Receiver Performance and LTE Compatibility Mark Waddell, Lead R&D Engineer 16 th November 2011 Research & Development

2 Contents Importance of the DTT platform in the UK Digital Switchover and the Digital Dividend Planned introduction of ECNs into the UHF TV Band Impact of ECN on DTT Reception Performance requirements Receiver Performance Characteristics BBC protection ratio tests with LTE interferers New DTG conformance test targets Conclusions Research & Development 2

3 What we are trying to protect. 50 TV channels 24 radio channels PVR and HD services Research & Development 3

4 Trends in UK TV Consumption Q million households using Terrestrial TV Platform 10.2 million for primary set 0.5 million adding pay TV DTT services 2 million on Analogue Terrestrial Research & Development 4

5 Trends in UK TV Consumption Q million households using Terrestrial TV Platform 10.1 million for primary set 0.3 million adding pay TV DTT services 1.8 million on Analogue Terrestrial Expected to adopt DTT when UK DSO completes in 2012 Research & Development 5

6 UK TV Spectrum Channel Interleaved Spectrum (DTT & PAL) PMSE (radio microphones) Radio Astronomy Aeronautical Radar MFN using 46 UHF channels (368MHz total) 11 TV Services (5xPAL + 6xDTT multiplexes) Licensed radio microphones (PMSE in interleaved white space spectrum) Research & Development 6

7 UK TV Spectrum 2013 The Digital Dividend Channel Interleaved Spectrum (DTT) PMSE (radio microphones) Cleared Spectrum 16 channels (128MHz) cleared for auction Upper cleared (9 channels) for ECNs (LTE) Lower cleared (7 channels) use to be determined 32 channels (256MHz) retained for 6 x DTT multiplexes and interleaved whitespace (licensed PMSE + licence-exempt WSDs) Research & Development 7

8 4G WRC07 Harmonized Band & DTT Compatibility UHF Band MHz 790 MHz 862 MHz Broadcasting Broadcasting MHz 790 MHz 8 MHz 8 MHz 8 MHz 8 MHz 8 MHz 8 MHz 8 MHz 8 MHz 862 MHz Guard band 1 MHz Downlink Duplex gap Uplink 6 x 5 MHz 11 MHz 6 x 5 MHz Broadcasting Mobile communications 790 MHz 862 MHz Research & Development 8

9 The DDR Interference Issue Illustration: Interference from ECN base stations Boundary of the DTT coverage area (95% location probability) DTT coverage area DTT transmitter Research & Development 9

10 The DDR Interference Issue Illustration: Interference from ECN base stations Low-power dense ECN network Boundary of the DTT coverage area (95% location probability) DTT coverage area Hole in DTT coverage Co-sited DTT transmitter and ECN base station Research & Development 10

11 The DDR Interference Issue Illustration: Interference from ECN base stations High-power dense ECN network Boundary of the DTT coverage area (95% location probability) DTT coverage area Hole in DTT coverage DTT transmitter Research & Development 11 Maximum EIRP limits range from 56 dbm/(5 MHz) to 64 dbm/(5 MHz). Higher limits may be authorised in specific cases, e.g. in rural areas.

12 LTE deployment and DTT C/I requirements LTE-BS C/I requirements Consider BS at 71m from fixed DTT receiver at broadcast cell edge LTE-UE C/I requirements Consider UE at 1.5m agl outside a fixed DTT installation Research & Development 12

13 LTE-BS to DTT Fixed Reference Geometry to Protect Fixed Reception LTE EIRP: 64dBm MCL 61dB: LTE level at DTT Rx : 3dBm DTT min : -74dBm (Service Edge) C/I < -77dB (!) 2 down-tilt 20 m BS P BS Coupling gain: G = -67 db 71 m +9 dbi TV 10 m Research & Development 13

14 LTE-UE to DTT Fixed Reference Geometry to Protect Fixed Reception UE EIRP: 23dBm MCL 50dB => LTE level at DTT Rx : -27dBm DTT min level: -77dBm C/I < -50dB Mobile UE Research & Development 14

15 Review of Detailed Tests on 10 Receivers Test Plan BS tests UE tests Preliminary Results & Initial Analysis Performance Variations Research & Development 15

16 Test Plan LTE BS A / DTT CH60 PR 60 3 x 10 MHz 11 MHz 791 MHz Downlink 821 MHz 832 MHz 3 x 10 MHz Uplink 862 MHz 790 MHz DTT CH60 Low and high levels [-70dBm, -40dBm] LTE BS License A Traffic loads: [Idle, 50%, 100% ] Research & Development 16

17 Test Plan LTE BS A / DTT CH59 PR 59 3 x 10 MHz 11 MHz 782 MHz 791 MHz Downlink 821 MHz 832 MHz 3 x 10 MHz Uplink 862 MHz DTT CH59 Low and high levels [-70dBm, -40dBm] LTE BS License A Traffic loads: [Idle, 50%, 100% ] Research & Development 17

18 Test Plan LTE BS A / DTT CH52 PR 52 3 x 10 MHz 11 MHz 726 MHz 791 MHz Downlink 821 MHz 832 MHz 3 x 10 MHz Uplink 862 MHz DTT CH52 Low and high levels [-70dBm, -40dBm] LTE BS License A Traffic loads: [Idle, 50%, 100% ] Research & Development 18

19 Test Plan LTE BS A/BC / DTT CH60 PR 60 3 x 10 MHz 11 MHz 791 MHz Downlink 821 MHz 832 MHz 3 x 10 MHz Uplink 862 MHz 790 MHz DTT CH60 Low and high levels [-70dBm, -40dBm] LTE BS License A + License BC Traffic loads: [Idle, 50%, 100% ] Research & Development 19

20 Test Plan LTE UE C / DTT CH60 PR 60 3 x 10 MHz 11 MHz 791 MHz Downlink 821 MHz 832 MHz 3 x 10 MHz Uplink 862 MHz 790 MHz DTT CH60 Low and high levels [-70dBm, -40dBm] LTE UE License C Traffic loads: [1Mb/s, 10Mb/s, 20Mb/s ] Research & Development 20

21 Test Plan LTE UE A / DTT CH60 PR 60 3 x 10 MHz 11 MHz 791 MHz Downlink 821 MHz 832 MHz 3 x 10 MHz Uplink 862 MHz 790 MHz DTT CH60 Low and high levels [-70dBm, -40dBm] LTE UE License A Traffic loads: [1Mb/s, 10Mb/s, 20Mb/s ] Research & Development 21

22 Results DTT Low Level (-70dBm) / LTE BS 100% Research & Development 22

23 Results DTT High Level (-40dBm) / LTE BS 100% Research & Development 23

24 Results DTT High Level (-40dBm) / LTE BS 50% Research & Development 24

25 Results DTT High Level (-40dBm) / LTE BS idle Research & Development 25

26 DTT CH60 C/I vs LTE BS A Traffic (100%, Idle) Research & Development 26

27 C/I vs LTE BS Traffic (%) Research & Development 27

28 C/I vs UE Traffic (Mb/s) Research & Development 28

29 DTG Zoo Tests Testing between 13 th 16 th December 2010 Agilent MXG used as the interferer LTE BS-A idle signal replayed at 12.5Msa/s ACLR >68dB 104 DTT receivers tested 75 DVB-T only 29 Dual mode (DVB-T/T2) tested in both modes No LTE UE testing BS tests analysed statistically Research & Development 29

30 LTE-800 BS DTG Zoo Test 1 PR BS-A x 10 MHz 11 MHz 3 x 10 MHz Downlink 790 MHz 821 MHz 832 MHz Uplink 862 MHz LTE BS-A at 796MHz: -15dBm ( peak power for idle traffic) DTT CH60 (786MHz; T and T2) Research & Development 30

31 LTE-800 BS DTG Zoo Test 2 PR BS-B x 10 MHz 11 MHz 3 x 10 MHz Downlink 790 MHz 821 MHz 832 MHz Uplink 862 MHz LTE BS-B at 806MHz: -15dBm ( peak power for idle traffic) DTT CH60 (786MHz; T and T2) Research & Development 31

32 Test Signal ACLR Measurement Generator ACLR ~68dB Measured using Agilent E4440A PSA spectrum analyser C.f. ECC(09) 03 requirement of 59dB Receiver C/I results will tend to be ACS limited Research & Development 32

33 Summary of Results 100 Protection Ratio Performance for LTE BS Idle into DTT CH60 (786MHz) % Receivers achieving C/I < x- axis value LTE A / Ch60 T LTE B / Ch60 T LTE A / Ch60 T2 LTE B / Ch60 T Corrected Protection Ratio C/I (db) Research & Development 33

34 LTE-A into DVB-T 100 Protection Ratio Performance for LTE BS Idle into DTT CH60 (786MHz) % Receivers achieving C/I < x- axis value LTE A / Ch60 T LTE B / Ch60 T LTE A / Ch60 T2 LTE B / Ch60 T Corrected Protection Ratio C/I (db) 82 % of receivers exceed C/I of -30dB Research & Development 34

35 LTE-A into DVB-T2 100 Protection Ratio Performance for LTE BS Idle into DTT CH60 (786MHz) % Receivers achieving C/I < x- axis value LTE A / Ch60 T LTE B / Ch60 T LTE A / Ch60 T2 LTE B / Ch60 T Corrected Protection Ratio C/I (db) 65 % of receivers exceed C/I of -30dB Result degraded by the small sample size and rogue receivers Research & Development 35

36 LTE-B into DVB-T / DVB-T2 100 Protection Ratio Performance for LTE BS Idle into DTT CH60 (786MHz) % Receivers achieving C/I < x- axis value LTE A / Ch60 T LTE B / Ch60 T LTE A / Ch60 T2 LTE B / Ch60 T Corrected Protection Ratio C/I (db) 78 % of receivers exceed C/I of -30dB Research & Development 36

37 DTG Conformance Tests for LTE Issues identified with some receivers Poor performance at low traffic DTG conformance tests developed Released into D Book V 7 published March 2011 Manufacturers can test and develop product LTE test signals published on BBC ftp site DTG starting testing with LTE test signal in November 2011 Compliance compulsory from March 2012 Requirement for Freeview and Freeview HD trademark Research & Development 37

38 LTE-800 BS DTG Conducted Test 1 >30dB x 10 MHz 11 MHz 3 x 10 MHz Downlink 790 MHz 821 MHz 832 MHz Uplink 862 MHz Interferer LTE 797MHz, 10MHz LTE = -15dBm Wanted at CH60 : <-45dBm Research & Development 38

39 LTE-800 BS DTG Conducted Test 2 >30dB x 10 MHz 11 MHz 3 x 10 MHz Downlink 790 MHz 821 MHz 832 MHz Uplink 862 MHz Interferer LTE 806MHz, 10MHz LTE = -15dBm Wanted at CH60 : <-45dBm Research & Development 39

40 LTE-800 UE Conducted Test 3 >30dB x 10 MHz 11 MHz 3 x 10 MHz Downlink 790 MHz 821 MHz 832 MHz Uplink 862 MHz Interferer LTE 857MHz, 10MHz BW; I=-15dBm Wanted at CH60 : <-45dBm I Research & Development 40

41 LTE-800 UE Conducted Test 4 >30dB x 10 MHz 11 MHz 3 x 10 MHz Downlink 790 MHz 821 MHz 832 MHz Uplink 862 MHz Interferer LTE 837MHz, 10MHz BW; I=-15dBm Wanted at CH60 : <-45dBm Research & Development 41

42 Conclusions Issues identified with some receivers Poor C/I performance at low traffic New DTG D-book tests developed to weed out worst Conformance test specification a partial solution Additional filters needed to bridge the performance gap Even with filters some CH60 areas will lose service Ofcom studies assuming LTE BS at 59dBm predict 750k HHs will lose DTT reception without mitigation 640k HHs with amplifiers and distribution systems 110k HHs with standard installation Research & Development 42

43 Thank you for your attention Research & Development 43