1GBASE-KR for 4G Backplane Nov 7 Technology Hiroshi Takatori Hiroshi.Takatori@.us 1
Outline This contribution discusses, - Performance based on 1GBASE-KR Std - Theoretical Limit (Saltz SNR) and Time Domain Simulation - Performance Improvement - Summary
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 = 3.3-18.7Log(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
Channel discussed by 1GBASE-KR TYCO, 7 Channels Description Channel Name Line Card No. Connectors Backplane Total Length Loss @ 5GHz TYCO 7 cases [1] Signal path One FEXT Two NEXT Case1 1 4.9dB Case 1 13 4 4.1 Case3 1 6 4 6.6 Case4 6 13 3 19. Case5 6 13 1 13 14. Case6 6 1 13 16.4 Case7 6 1 13 1.9 [1] http://www.ieee8.org/3/ap/public/sep4/dambrosia_1_94.pdf 4
Description Channel discussed by 1GBASE-KR Molex, channels and Intel, 8 channels Channel Name Line Card No. Connectors Backplane Total Length Loss @ 5GHz Molex cases [] Signal oath 3 FEXT 4 NEXT 1m_Improved _1.5 +.5 35 4.6 1m_Improved _.5 + 1.5 (?) 5 38 17.8 Intel 8 cases [3] Signal path FEXT 6NEXT T1 T1-6 -6 16.8 4.4 T -6 7.4 B1-6 8.9 B1-6 14.1 B -6 17.4 M1-6 1.3 M -6 19.8 [] http://www.ieee8.org/3/ap/public/mar6/oganessyan_1_36.pdf [3] http://www.ieee8.org/3/ap/public/jun5/peters_1_65.pdf 5
IL and ICR -1 ILmax -1-1 SDD1 (db) - -3-4 -5 14~7dB TYCO 7 channels - -3-4 -5 18~.5dB Molex channels - -3-4 -5 9~7dB Intel 8 channels -6 1M 1E+8 5E+8 1E+9 1G 5E+9 1G 1E+1 E+1 Frequency (Hz) -6-6 1M 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 6 6 6 5 ICRmin HIGH CONFIDENCE 5 HIGH CONFIDENCE 5 HIGH CONFIDENCE 4 REGION 4 REGION 4 REGION 3 3 3 ICR (db) 1 TYCO 1 Molex 1 Intel -1-1 -1 - - - -3 1M 1E+8 5E+8 1E+9 1G 5E+9 1E+1 1G E+1 Frequency (Hz) -3-3 1M 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
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
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) 4 1 18 15 1 9 6 3 Black: 5.mV Broadband noise Blue: Crosstalk Red: Crosstalk + IC Noise 6dB Margin Transmit power: 1dBm (.4Vop with.75fs 1 st order low-pass) 1 3 4 5 6 7 8 9 1 11 1 13 14 15 16 17 18 19 1 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
Jitter and Implementation Loss A time domain simulator is created for nd step. RX Jitter TX-Pre-EQL Initial Settings by Standard (-.75 + 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
Jitter and Implementation Loss SNR (db) Level 35 3 5 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 1 1 3 4 5 6 7 8 9 1 Iteration Time (# of million symbols) 1
Margin with Jitter and IC Jitter and IC implementation loss + Crosstalk + -14dBm/Hz IC noise Receiver Resource: 8 tap FFE + 18 tap DFE 18 15 1 Theoretical margin Result represents high performance design and could degrade more. Noise Margin (db) 9 6 3 6dB Margin Marginal for many cases. Industrial systems need to be robust against alien noise, impulsive noise, etc. Margin with Jitter and IC implementation -3 1 3 4 5 6 7 8 9 1 11 1 13 14 15 16 17 18 19 1 How can they be improved? 7 TYCO Molex 8 INTEL Additions 11
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 1 3 4 5 6 7 8 9 1 11 1 Iteration Time (# of million symbols) 1
Crosstalk Canceller Crosstalk cancellation is possible with 4-lane structure of 4G backplane. 18 Noise Margin (db) 15 1 9 6 3 w/o Crosstalk Canceller With Crosstalk Canceller 6dB Margin -3 1 3 4 5 6 7 8 9 1 11 1 13 14 15 16 17 18 19 1 7 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
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