1. 1 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance ADVANCED PHY PERFORMANCE RON HRANAC Note: This presentation is intended for Cisco internal audiences and customers under NDA only. This presentation contains confidential intellectual property information that is proprietary to Broadcom Corporation and Texas Instruments.

2. 222 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance DOCSIS ® Background DOCSIS 1.0 gave us standards-based interoperability, which means “certified” cable modems from multiple vendors work with “qualified” cable modem termination systems (CMTSs) from multiple vendors. DOCSIS 1.1 added a number of features, including quality of service (QoS), more robust scheduling, packet classification and other enhancements that facilitate voice services. Data Over Cable Service Interface Specification

3. 333 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance DOCSIS Background DOCSIS 1.0 and 1.1—collectively known as DOCSIS 1.x— support two downstream modulation formats: 64-QAM (quadrature amplitude modulation) and 256-QAM. Modulation formatChannel bandwidth, MHz Symbol rate, Msym/sec Raw data rate, Mbps Nominal data rate, Mbps 64-QAM (DOCSIS)65.05694130.34~27 256-QAM (DOCSIS)65.36053742.88~38 64-QAM (Euro-DOCSIS)86.95241.71~37 256-QAM (Euro-DOCSIS)86.95255.62~50

4. 444 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance DOCSIS Background DOCSIS 1.x supports several upstream data rates, ranging from a low of 320 kbps to a high of 10.24 Mbps. It also supports two modulation formats— quadrature phase shift keying (QPSK) and 16- QAM—as well as five upstream RF channel bandwidths. Channel bandwidth, MHz Symbol rate, ksym/sec QPSK raw data rate, Mbps QPSK nominal data rate, Mbps 16-QAM raw data rate, Mbps 16-QAM nominal data rate, Mbps 0.2001600.32~0.30.64~0.6 0.4003200.64~0.61.28~1.2 0.8006401.28~1.22.56~2.4 1.601,2802.56~2.35.12~4.8 3.202,5605.12~4.610.24~9.0

5. 555 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance DOCSIS Background DOCSIS 1.1 added some enhancement to upstream transmission robustness, using 8-tap adaptive equalization. DOCSIS 2.0: Higher upstream data throughput per RF channel, up to 30.72 Mbps DOCSIS 2.0 supports 64-QAM in the upstream—plus 8-QAM and 32-QAM—and optionally supports 128-QAM trellis coded modulation (TCM) encoded modulations for S-CDMA channels. Higher orders of modulation require more robust data transmission To facilitate more robust upstream data transmission, DOCSIS 2.0 introduced advanced PHY

6. 666 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Advanced PHY – 2 nd Generation Burst Mode RX Direct sampled RF front end Ingress cancellation Frequency stacking Spectrum management Improved adaptive equalizer from 2.0 Spec Improved burst mode RX preamble Improves 1.x as well as 2.0 cable modems What is Advanced PHY? PHY: Physical Layer

7. 777 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance What is Advanced PHY? Symbol (T)-spaced adaptive equalizer with 24 taps compared to 8 taps in DOCSIS 1.x Allows operation in the presence of more severe multipath and microreflections, and should accommodate signals near the band edge where group delay is more prevalent Improved burst acquisition Carrier and timing lock, power estimates, equalizer training and constellation phase lock are all done simultaneously. This allows shorter preambles, and reduces implementation loss. Better forward error correction (FEC) DOCSIS 1.x provides for the correction of up to 10 errored bytes per Reed Solomon block (T=10) with no interleaving, while DOCSIS 2.0 allows correction of up to 16 bytes per Reed Solomon block (T=16) with programmable interleaving.

8. 888 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance What is Advanced PHY? Advanced PHY silicon incorporates ingress cancellation technology in the upstream receiver chip, which further enhances upstream data transmission robustness. Think of ingress cancellation as a way to digitally remove in-channel impairments such as ingress and common path distortion.

9. 999 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Performance Concepts Implementation Margin Closeness to ‘theoretical’ in an additive white Gaussian noise (AWGN) environment Example – If the theoretical bit error rate (BER) at 21 dB carrier-to- noise ratio (CNR) is 1x10 -6 but a CMTS actually needs 23 dB CNR to achieve a 1x10 -6 BER, the implementation margin is 2 dB. Processing Gain Processing to improve performance (e.g., FEC or ingress cancellation) Example – When ingress cancellation is turned off and a carrier-to- interference ratio (C/I) of 10 dB yields 1x10 -6 BER, then turning on ingress cancellation allows C/I = 0 dB for 1x10 -6 BER, processing gain is 10 dB.

10. 10 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC16C/S, MC28C/E Burst Mode Receivers - 1 st Generation Broadcom’s BCM3137 is within 2 dB of theory @16-QAM Implementation margin of analog receiver (VCO, SAW…) adds another 2-3 dB AND Broadcom Confidential

11. 11 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U/X – 2 nd Generation Direct Sampled Burst Mode Digital Receiver All frequency conversion and selectivity in PHY ASIC Total implementation margin < 0.5 dB of theory

12. 12 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U/X MC16U/X – Annex A/B Upstream Broadcom BCM3138 (same as BCM3140 2.0 chip, but without S-CDMA) 5-65 MHz dual A-TDMA, adaptive ingress cancellation, integrated FFT Downstream – Broadcom BCM3034 Annex A/B Modulator No SAW filter required with downstream chip MC5x20U – Annex A/B Upstream Texas Instruments TI4522 series 5-65 MHz A-TDMA, advanced PHY including ingress cancellation Downstream – Broadcom BCM3034 Annex A/B modulator No SAW filter required with downstream chip Cisco’s Advanced PHY

13. 13 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Cisco’s Advanced PHY Advanced RF front end and Cisco MAC hardware, allow Cisco’s MC5x20U and MC28U Broadband Processing Engines (BPE) to offer improved capacity, performance and reliability. Operates within 0.5 dB of theory Advanced PHY with ingress cancellation Greater than 17 Mbps single modem upstream throughput Line rate DOCSIS 1.1 and 2.0 processing using the advanced Cisco DOCSIS MAC technology

14. 14 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Cisco’s Line Card RF Front End High density—2 downstreams, 8 upstreams (MC28U) or 5 downstreams, 20 upstreams (MC5x20U) per line card Enhanced RF robustness Embedded upstream ingress cancellation Direct sampling Integrated upconverters ATDMA-capable

15. 15 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance RF Performance: BER vs. AWGN

16. 16 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U Packet Error Rate Versus AWGN Frequency: 30 MHz Mod: QPSK Symbol Rate: 1,280 ksym/sec Power: 0 dBmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=84 RS_T=3 QPSK

17. 17 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U Packet Error Rate Versus AWGN Frequency: 30 MHz Mod: 16QAM Symbol Rate: 1,280 ksym/sec Power: 0 dBmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=88 RS_T=5 16-QAM

18. 18 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U Packet Error Rate Versus AWGN Frequency: 30 MHz Mod: 64QAM Symbol Rate: 5,120 ksym/sec Power: 0 dBmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=96 RS_T=9 64-QAM

19. 19 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U/MC28C Comparison Frequency: 30 MHz Mod: QPSK Symbol Rate: 1,280 ksym/sec Power: 0 dBmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=84 RS_T=3

20. 20 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28U/MC28C Comparison Frequency: 30 MHz Mod: 16-QAM Symbol Rate: 1,280 ksym/sec Power: 0 dBmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=88 RS_T=5

21. 21 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC520S/U BER Versus AWGN QPSK Within Measurement Uncertainty of Theory

22. 22 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC520S/U BER Versus AWGN 16-QAM Within Measurement Uncertainty of Theory

23. 23 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC520S/U BER Versus AWGN 64-QAM Within Measurement Uncertainty of Theory

24. 24 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Lower Implementation Margin Advantages Can operate at lower CNR for a given BER than earlier generation CMTSs Provides improved operating headroom

25. 25 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance RF Performance: Ingress Cancellation

26. 26 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance 16-QAM 10 -8 BER Opens previously unusable spectrum Enables reliable operation in the presence of ingress Narrowband and wideband Works with all DOCSIS 1.0, 1.1, & 2.0 cable modems Ingress Cancellation Texas Instruments Confidential

27. 27 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance MC28/16 U/X w/ Broadcom BCM3138 Adaptive Ingress Cancellation RX AFEDemod Ingress Cancel & Equalizer Broadcom Confidential

28. 28 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Broadcom BCM3138 Ingress Performance Symbol Rate = 5.12 MHzCluster SNR = 28.83 dB Static CW Ingress (64-QAM, SIR = 0 dB) Broadcom Confidential

29. 29 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Broadcom BCM3138 Ingress Performance Symbol Rate = 5.12 MHz Wideband Ingressors 20 kHz and 100 kHz (16-QAM, SIR = 9 dB) Cluster SNR = 20.96 dB Broadcom Confidential

30. 30 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Broadcom BCM3138 Ingress Performance Symbol Rate = 5.12 MHz Four CW Ingressors (64 QAM, SIR = 6 dB) Cluster SNR = 26.94 dB Broadcom Confidential

31. 31 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Broadcom BCM3138 Ingress Performance Four CW Ingressors (16-QAM, SIR = 0 dB) Cluster SNR = 22.79 dB Broadcom Confidential

32. 32 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance CableLabs PHY22B Ingress Cancellation C/I Single CW Ingress QPSK 1.28MBaud AWGN = -20 dB 16QAM 2.56MBaud AWGN = -25dB 64QAM 5.12Mbaud AWGN = -30dB MC28/16U/X-20.2 dB-18.2 dB-10.7 dB CableLabs optional PHY test Packet error rate in presence of single CW interferer & AWGN PER <0.5%, 64-byte packets Note: Negative C/I indicates interferer is larger than desired signal

33. 33 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance RF Performance: Receive Equalizer

34. 34 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance DOCSIS 2.0 ADTMA Equalizer DOCSIS 1.1 specifies an 8-tap T-Spaced Pre-Equalizer which can mitigate micro- reflections of –10dB (at.5 micro-sec delay) with 27 dB MSE DOCSIS 1.1 Pre-Equalizer enables reliable operation at 16-QAM in channels that could only support QPSK in DOCSIS 1.0 DOCSIS 2.0 specifies a 24-tap T-Spaced Pre-Equalizer which can mitigate micro- reflections of –10dB (at.5 micro-sec delay) with 33 dB MSE DOCSIS 2.0 Pre-Equalizer can enable reliable operation at 64-QAM even in channels that can only support QPSK in DOCSIS 1.0 Cisco Systems Confidential 24-tap adaptive equalizer can operate in DOCSIS 1.0 Mode to compensate linear plant errors (slope, group delay, microreflections) increasing DOCSIS 1.0 modem channel capacity

35. 35 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance 24-Tap Adaptive Equalizer BER < 1x10 -8 : Reed Solomon T=0 (Off) DOCSIS 1.0 8-tap equalizer could only support QPSK or 1.28 Msym/sec Operate 1.0 cable modems at band edge 16-QAM 2.56 Msym/sec over –3.4dB slope and 125 nsec group delay Impaired 39 – 42 MHz Band

36. 36 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance RF Performance: Downstream MER

37. 37 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance RF Downstream Path DSx High Speed D/A BCM3034 Modulator UPX DSx UPX High Speed D/A BCM3033 Modulator SAW MC16C/S MC28U/16U No SAW Filter !!

38. 38 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Downstream Constellation 256-QAM @ 857 MHz Total EVM = 1.18% !

39. 39 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Does Advanced PHY Work?

40. 40 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance SCTE Cable-Tec Expo Advanced PHY Demo AM carriers from comb generator No packet loss!

41. 41 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance SCTE Cable-Tec Expo Advanced PHY Demo CPD from downstream feed and diode circuit No packet loss!

42. 42 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance SCTE Cable-Tec Expo Advanced PHY Demo Noise from HP signal generator No packet loss!

43. 43 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance SCTE Cable-Tec Expo Advanced PHY Demo CBT screen shot showing all three impairments

44. 44 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance 24-Tap Adaptive Equalization Lab Test 6.4 MHz bandwidth 64-QAM signal After adaptive equalization: No correctable FEC errors and the CMTS’s upstream SNR estimate increased to 36+ dB Before adaptive equalization: Correctable FEC errors were incrementing about 7000 codewords per second (232 bytes per codeword). The CMTS’s upstream SNR (MER) estimate was 23 dB

45. 45 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Customer Field Test 16-QAM signal riding on top of S-CDMA signal, with CW carrier in-channel No packet loss!

46. 46 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Customer Field Test Spectrum analyzer screen shot showing 16-QAM signal at ~12 MHz center frequency No packet loss!

47. 47 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance Advanced PHY: The Bottom Line Improves upstream data transmission robustness Allows use of spectrum that was previously unusable Facilitates higher orders of modulation Provides additional operating headroom Many advanced PHY features work with DOCSIS 1.x cable modems Cost-effective way to kick-start the deployment of new services

48. Q and A 48 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance

49. 49 © 2003 Cisco Systems, Inc. All rights reserved. Advanced PHY Performance