ADVANCED PHY PERFORMANCE RON HRANAC Note This presentation

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. Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 1

DOCSIS® Background Data Over Cable Service Interface Specification • 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 (Qo. S), more robust scheduling, packet classification and other enhancements that facilitate voice services. Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 2

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 format Advanced PHY Performance Channel bandwidth, MHz Symbol rate, Msym/sec Raw data rate, Mbps Nominal data rate, Mbps 64 -QAM (DOCSIS) 6 5. 056941 30. 34 ~27 256 -QAM (DOCSIS) 6 5. 360537 42. 88 ~38 64 -QAM (Euro-DOCSIS) 8 6. 952 41. 71 ~37 256 -QAM (Euro-DOCSIS) 8 6. 952 55. 62 ~50 © 2003 Cisco Systems, Inc. All rights reserved. 3

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 16 -QAM raw nominal data rate, Mbps 16 -QAM nominal data rate, Mbps 0. 200 160 0. 32 ~0. 3 0. 64 ~0. 6 0. 400 320 0. 64 ~0. 6 1. 28 ~1. 2 0. 800 640 1. 28 ~1. 2 2. 56 ~2. 4 1. 60 1, 280 2. 56 ~2. 3 5. 12 ~4. 8 3. 20 2, 560 5. 12 ~4. 6 10. 24 ~9. 0 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 4

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 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 5

What is Advanced PHY? PHY: Physical Layer • 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 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 6

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. Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 7

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. Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 8

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

MC 16 C/S, MC 28 C/E Burst Mode Receivers - 1 st Generation Broadcom’s BCM 3137 is within 2 d. B of theory @16 -QAM AND Implementation margin of analog receiver (VCO, SAW…) adds another 2 -3 d. B Advanced PHY Performance Broadcom Confidential © 2003 Cisco Systems, Inc. All rights reserved. 10

MC 28 U/X – 2 nd Generation Direct Sampled Burst Mode Digital Receiver All frequency conversion and selectivity in PHY ASIC Total implementation margin < 0. 5 d. B of theory Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 11

Cisco’s Advanced PHY MC 28 U/X MC 16 U/X – Annex A/B Upstream Broadcom BCM 3138 (same as BCM 3140 2. 0 chip, but without S-CDMA) 5 -65 MHz dual A-TDMA, adaptive ingress cancellation, integrated FFT Downstream – Broadcom BCM 3034 Annex A/B Modulator No SAW filter required with downstream chip MC 5 x 20 U – Annex A/B Upstream Texas Instruments TI 4522 series 5 -65 MHz A-TDMA, advanced PHY including ingress cancellation Downstream – Broadcom BCM 3034 Annex A/B modulator No SAW filter required with downstream chip Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 12

Cisco’s Advanced PHY • Advanced RF front end and Cisco MAC hardware, allow Cisco’s MC 5 x 20 U and MC 28 U Broadband Processing Engines (BPE) to offer improved capacity, performance and reliability. Operates within 0. 5 d. B 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 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 13

Cisco’s Line Card RF Front End • High density— 2 downstreams, 8 upstreams (MC 28 U) or 5 downstreams, 20 upstreams (MC 5 x 20 U) per line card • Enhanced RF robustness • Embedded upstream ingress cancellation • Direct sampling • Integrated upconverters • ATDMA-capable Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 14

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

MC 28 U Packet Error Rate Versus AWGN QPSK Frequency: 30 MHz Mod: QPSK Symbol Rate: 1, 280 ksym/sec Power: 0 d. Bmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=84 RS_T=3 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 16

MC 28 U Packet Error Rate Versus AWGN 16 -QAM Frequency: 30 MHz Mod: 16 QAM Symbol Rate: 1, 280 ksym/sec Power: 0 d. Bmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=88 RS_T=5 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 17

MC 28 U Packet Error Rate Versus AWGN 64 -QAM Frequency: 30 MHz Mod: 64 QAM Symbol Rate: 5, 120 ksym/sec Power: 0 d. Bmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=96 RS_T=9 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 18

MC 28 U/MC 28 C Comparison Frequency: 30 MHz Mod: QPSK Symbol Rate: 1, 280 ksym/sec Power: 0 d. Bmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=84 RS_T=3 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 19

MC 28 U/MC 28 C Comparison Frequency: 30 MHz Mod: 16 -QAM Symbol Rate: 1, 280 ksym/sec Power: 0 d. Bmv Packet Size: 64 Bytes Packet Rate: 100 Packets: 1000000 RS_N=88 RS_T=5 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 20

MC 520 S/U BER Versus AWGN Within Measurement Uncertainty of Theory QPSK Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 21

MC 520 S/U BER Versus AWGN Within Measurement Uncertainty of Theory 16 -QAM Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 22

MC 520 S/U BER Versus AWGN Within Measurement Uncertainty of Theory 64 -QAM Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 23

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

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

Ingress Cancellation • Opens previously unusable spectrum • Enables reliable operation in the presence of ingress • Narrowband wideband • Works with all DOCSIS 1. 0, 1. 1, & 2. 0 cable modems Advanced PHY Performance 16 -QAM 10 -8 BER Texas Instruments Confidential © 2003 Cisco Systems, Inc. All rights reserved. 26

MC 28/16 U/X w/ Broadcom BCM 3138 Adaptive Ingress Cancellation RX AFE Advanced PHY Performance Demod Ingress Cancel & Equalizer Broadcom Confidential © 2003 Cisco Systems, Inc. All rights reserved. 27

Broadcom BCM 3138 Ingress Performance Static CW Ingress (64 -QAM, SIR = 0 d. B) Symbol Rate = 5. 12 MHz Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. Cluster SNR = 28. 83 d. B Broadcom Confidential 28

Broadcom BCM 3138 Ingress Performance Wideband Ingressors 20 k. Hz and 100 k. Hz (16 -QAM, SIR = 9 d. B) Symbol Rate = 5. 12 MHz Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. Cluster SNR = 20. 96 d. B Broadcom Confidential 29

Broadcom BCM 3138 Ingress Performance Four CW Ingressors (64 QAM, SIR = 6 d. B) Symbol Rate = 5. 12 MHz Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. Cluster SNR = 26. 94 d. B Broadcom Confidential 30

Broadcom BCM 3138 Ingress Performance Four CW Ingressors (16 -QAM, SIR = 0 d. B) Cluster SNR = 22. 79 d. B Advanced PHY Performance Broadcom Confidential © 2003 Cisco Systems, Inc. All rights reserved. 31

Cable. Labs PHY 22 B Ingress Cancellation Cable. Labs 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 C/I QPSK 16 QAM 64 QAM Single CW Ingress 1. 28 MBaud 2. 56 MBaud 5. 12 Mbaud AWGN = -20 d. B AWGN = -25 d. B AWGN = -30 d. B -20. 2 d. B -18. 2 d. B -10. 7 d. B MC 28/16 U/X Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 32

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

DOCSIS 2. 0 ADTMA Equalizer • DOCSIS 1. 1 specifies an 8 -tap T-Spaced Pre-Equalizer which can mitigate microreflections of – 10 d. B (at. 5 micro-sec delay) with 27 d. B 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 microreflections of – 10 d. B (at. 5 micro-sec delay) with 33 d. B 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 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 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. Cisco Systems Confidential 34

24 -Tap Adaptive Equalizer Operate 1. 0 cable modems at band edge 16 -QAM 2. 56 Msym/sec over – 3. 4 d. B slope and 125 nsec group delay Impaired 39 – 42 MHz Band BER < 1 x 10 -8 : Reed Solomon T=0 (Off) DOCSIS 1. 0 8 -tap equalizer could only support QPSK or 1. 28 Msym/sec Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 35

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

RF Downstream Path MC 16 C/S BCM 3033 High Speed D/A Modulator SAW UPX DSx MC 28 U/16 U No SAW Filter !! BCM 3034 Modulator Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. High Speed D/A UPX DSx 37

Downstream Constellation 256 -QAM @ 857 MHz Total EVM = 1. 18% ! Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 38

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

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

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

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

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

24 -Tap Adaptive Equalization Lab Test 6. 4 MHz bandwidth 64 -QAM signal 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 d. B After adaptive equalization: No correctable FEC errors and the CMTS’s upstream SNR estimate increased to 36+ d. B Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 44

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

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

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 Advanced PHY Performance © 2003 Cisco Systems, Inc. All rights reserved. 47

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

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