10GBASE-KR for 40G Backplane

Transcription

1 1GBASE-KR for 4G Backplane Nov 7 Technology Hiroshi Takatori Hiroshi.Takatori@.us 1

2 Outline This contribution discusses, - Performance based on 1GBASE-KR Std - Theoretical Limit (Saltz SNR) and Time Domain Simulation - Performance Improvement - Summary

3 4G Backplane A Single Lane, 1GBASE-KR 8.3ap, Clause 7 Main Requirements Signaling: 1.315Gbaud(+/-1ppm), PAM Transmitter: 1mVpp Max, 3-tap Pre-Equalization, Total Jitter < 8%UIpp Return Loss: 9dB 5M ~.5GHz, 1dB/dec. from.5 ~ 7.5GHz Insertion Loss: < ILmax(f), 4.5dB at 5GHz, Informative Cross-talk: Defined as ICR, Ratio of IL to Power sum crosstalk, PSXT ICR > ICRmin = Log(f/5G), Informative BER: Better than 1**(-1) Receiver Interference Tolerance Broadband noise: 5.mVrsm(5GHzband) Jitter UI p-p: 13% (random), 3.5%(DCD), 11.5%(sinusoidal) Total 17 channels are uploaded to verify the system performance. 3

4 Channel discussed by 1GBASE-KR TYCO, 7 Channels Description Channel Name Line Card No. Connectors Backplane Total Length 5GHz TYCO 7 cases [1] Signal path One FEXT Two NEXT Case dB Case Case Case Case Case Case [1] 4

5 Description Channel discussed by 1GBASE-KR Molex, channels and Intel, 8 channels Channel Name Line Card No. Connectors Backplane Total Length 5GHz Molex cases [] Signal oath 3 FEXT 4 NEXT 1m_Improved _ m_Improved _ (?) Intel 8 cases [3] Signal path FEXT 6NEXT T1 T T B B B M M [] [3] 5

6 IL and ICR -1 ILmax -1-1 SDD1 (db) ~7dB TYCO 7 channels ~.5dB Molex channels ~7dB Intel 8 channels -6 1M 1E+8 5E+8 1E+9 1G 5E+9 1G 1E+1 E+1 Frequency (Hz) M 1E+8 5E+8 1E+9 1G 5E+9 1E+1 1G E+1 1M 1E+8 5E+8 1E+9 1G 5E+9 1E+1 1G E ICRmin HIGH CONFIDENCE 5 HIGH CONFIDENCE 5 HIGH CONFIDENCE 4 REGION 4 REGION 4 REGION ICR (db) 1 TYCO 1 Molex 1 Intel M 1E+8 5E+8 1E+9 1G 5E+9 1E+1 1G E+1 Frequency (Hz) M 1E+8 5E+8 1E+9 1G 5E+9 1E+1 1G E+1 1M 1E+8 5E+8 1E+9 1G 5E+9 1E+1 1G E+1 No cases are in HIGH CONFIDENCE 6

7 Performance Study The purpose is to confirm 1GBASE-KR applicability for 4G. 1 st Step: Calculate theoretical SNR (Saltz) against broadband noise, measured crosstalk, and IC electronic noise. nd Step: Check Jitter and other IC implementation loss by the time domain simulator 3 rd Step: Performance Improvement by Crosstalk Canceller Noise Margin is used throughout the discussion. Noise Margin = [Achievable SNR] SNRrequired SNRrequired is 17dB for PAM, BER = 1 **-1 It is preferred to be greater than on the order of 6dB for a robust operation. 7

8 Noise Margin by Saltz Three scenarios : 1. 5.mV-rms broadband noise defined by 1GBase-KR Receiver Interference Tolerance. Measured crosstalk from S-parameter 3. Crosstalk + -14dBm/Hz (IC electronic noise 3nV/sqrt(Hz) into 1ohm) Noise Margin (db) Black: 5.mV Broadband noise Blue: Crosstalk Red: Crosstalk + IC Noise 6dB Margin Transmit power: 1dBm (.4Vop with.75fs 1 st order low-pass) All except few cases met 6dB margin. Feasible subject to IC noise floor. The result does not include - Jitter - Implementation loss TYCO Molex INTEL Additions Backplane Channel Provided to the 8.3ap 8

9 Jitter and Implementation Loss A time domain simulator is created for nd step. RX Jitter TX-Pre-EQL Initial Settings by Standard ( D.41D**) TX Jitter Back Plane Channel NEXT and FEXT IC electronic Noise Receivers IC Termination: IEEE P8.3ap Document An Eye on Return Loss, by Richard Melliitz, Intel 14-May-5 SNR TX Jitter.8UIpp (5 sigma) jitter RX Jitter.1 UIrms random jitter (VCO) + systematic timing recovery jitter (bigger than receiver interference tolerance) IC Electronic Noise -14dBm/Hz FFE 8tap DFE 16, 3, 64, and 18tap Crosstalk Canceller added later as an option 9

10 Jitter and Implementation Loss SNR (db) Level IC Noise Sampled Eye Diagram Jitter SNR X-talk Following impairments are added one by one after the receiver is fully activated after 1 million-symbol iterations. - IC noise, -14dBm/Hz - TX and RX Jitter - DFE tap length reduction, 18, 64, 3, 16 - FEXT + NEXT CH1(Intel T) is shown as an example. All channels were simulated to verify the degradation. 15 DFE Tap length change Iteration Time (# of million symbols) 1

11 Margin with Jitter and IC Jitter and IC implementation loss + Crosstalk + -14dBm/Hz IC noise Receiver Resource: 8 tap FFE + 18 tap DFE Theoretical margin Result represents high performance design and could degrade more. Noise Margin (db) dB Margin Marginal for many cases. Industrial systems need to be robust against alien noise, impulsive noise, etc. Margin with Jitter and IC implementation How can they be improved? 7 TYCO Molex 8 INTEL Additions 11

12 Crosstalk Canceller Sampled Eye Crosstalk cancellation mode ( million iterations) is added at the end of the behavioral simulation. Level Margin was improved by 7dB in this example (CH1, Intel case-3). 35 Similar improvements shown in the previous chart were confirmed for all cases. SNR (db) 3 5 IC Noise Jitter SNR Canceller X-talk 7dB improvement 15 1 DFE Tap length change Iteration Time (# of million symbols) 1

13 Crosstalk Canceller Crosstalk cancellation is possible with 4-lane structure of 4G backplane. 18 Noise Margin (db) w/o Crosstalk Canceller With Crosstalk Canceller 6dB Margin TYCO Molex 8 INTEL Additions More than 6dB improvement can be made with crosstalk canceller. Another ~db improvement can be with optional FEC. 6dB margin is feasible. 13

14 Summary Performance of 1GBASE-KR is estimated with key IC implementation impairments. - Performance is marginal with the industrial grade backplane channels. - Solution as crosstalk canceller. - Even better margin can be obtained by with optional FEC. - Recommend HSSG to define additional channel bundling parameters to address crosstalk. Therefore, 1GBASE-KR is a good fit as a baseline for 4G system. 14