Line Coding Considerations for 10BASE-T1S

Transcription

1 Line Coding Considerations for 1BASE-T1S December 2, 217 Jay Cordaro, Mehdi Kilani, Ahmad Chini, Mehmet Tazebay Broadcom Version 1. IEEE 82.3cg Task Force December 2, 217 Page 1

2 Objective The purpose of this presentation is to Provide pros and cons for DME & NRZ Provide information for power spectral density Provide channel information for PHY analysis Provide supporting data for 1BASE-T1 line coding, and line data rate for multipoint channels Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 2

3 Pros & Cons DME Manchester Encoded inherently DC balanced Scrambler would help emissions Does not require equalizer for 1BASE-T1S channels (no DC) Requires ~2x bandwidth of NRZ PAM-2 Not DC Balanced Scrambler required Requires Equalizer for 1BASE-T1S channels due to PoDL and low frequency noise Requires1 bit per baud NRZ Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 3

4 Configuration for Channel Measurements Multipoint configuration (8 nodes) per buntz_1spe_5b_329.pdf (Buntz) presentation on 29 March 217. Passive linear topology (max) as follows:.1m 7.9m 7.9m.8m Cable segments using 1BASE-T1 cable with 1mm stubs. Evaluate frequency response under the following conditions: Nodes 1 and H terminated at 1 Ω Nodes 2-7 terminated at 1KΩ when silent and receiving Nodes 2-7 terminated at 1Ω while transmitting Investigate frequency response With inner nodes TX/RX including adjacent nodes Worst-case attenuation H Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 4

5 Simulation Setup for Eye Diagrams TX h(t) + + RX LPF 2nd Order HPF 1st Order AWGN 3dB CW NBI 3mVpp HPF 1st Order LPF 2nd Order TX: 64 byte, 25Mbps random data frames DME with 4ns data pulse width NRZ with 4ns data pulse width TX Voltage: 1Vpk-pk at transmitter (matched load?) TX LPF: 2 nd order Butterworth 3dB cutoff of 27MHz for DME 3dB cutoff of 2MHz for NRZ TX HPF: 1 st order, 3dB cutoff of 1kHz (for PoDL) White noise 3dB SNR h(t) Max channels CW of 3mV pk-pk 1-3MHz at RX input RX HPF: 1 st order 1MHz for DME 4 MHz for NRZ RX LPF: 2 nd order No equalization for simulation Matched Filter for DME receiver Matched Filter for NRZ receiver Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 5

6 Automotive Noise Recall from buntz_3bp_1_313.pdf[1]: In-car noise has a large low-frequency component. [1] Common Mode Noise on an automotive dataline from buntz_3bp_1_313.pdf on 13 Mar 213 Version 1. Broadcom Proprietary & Confidential. 211 Broadcom Corporation. All rights reserved. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 6

7 Transmit Power Spectral Comparison 1 Volt pk-pk measured on 1Ω Low-frequency vehicle [1] and PoDL noise DME more spectrally compatible to automotive noise and PoDL than NRZ for 1BASE-T1S Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 7

8 Channel Frequency Response Node 2->Node 3.8m 7.9m H 1Ω 7 1K Ω 6 1KΩ 5 1K Ω 4 1KΩ 3 1KΩ 2 1Ω Node 2: Tx(1W) Node 3: Rx(1KW) Node 1: Terminated(1W) Node H: Terminated(1W) All other nodes: 1KW Cable IL Frequency response Relatively flat insertion loss Freq(MHz) Cable RL Frequency response 7.9m -1.1m 1 1 Ω -2-3 Return loss makes EC difficult Freq(MHz) Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 8

9 Eye Diagram for DME Node 2->Node 3 Channel: Node 2->3 (buntz.. Max ) Matched filter output DME No CW Node 2->Node Matched Filter Output Timing offset in ns Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 9

10 Eye Diagram for NRZ 2->Node 3 Channel: Node 2->3 (buntz.. Max ) 3 Matched Filter Output NRZ No CW Node 2->Node Matched Filter Output Timing offset in ns Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 1

11 Channel Frequency Response Node 1->Node H.8m 7.9m H 1Ω 7 1K Ω 6 1KΩ 5 1K Ω Node 1: Tx(1W) Node H: Rx(1W) All Others: 1KW Sdd12 (db) -1-2 Cable IL Frequency response 4 1KΩ 3 1KΩ 2 1KΩ Freq(MHz) Cable RL Frequency response 7.9m.1m 1 1Ω Sdd11 (db) Freq(MHz) Version 1. Broadcom Proprietary & Confidential. 211 Broadcom Corporation. All rights reserved. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 11

12 Eye Diagram for DME Node 1->Node H Channel: Node 1->H (buntz.. Max ) Matched filter output DME No CW Node 1->Node H Matched Filter Output Timing offset in ns Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 12

13 Eye Diagram for NRZ Node 1 -> Node H Channel: Node 1->H (buntz.. Max ) 1.5 Matched Filter Output NRZ no CW Node 1->Node H 1.5 Matched Filter Output Timing offset in ns Version 1. Broadcom Proprietary & Confidential. 211 Broadcom Corporation. All rights reserved. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 13

14 Channel Frequency Response Node 2->Node H.8m 7.9m H 1Ω 7 1K Ω 6 1KΩ 5 1K Ω 4 1KΩ 3 1KΩ 2 1Ω Node 1: Terminated (1W) Node H: Rx(1W) Node 2: TX (1W) All Others 1kW Sdd12 (db) Cable IL Frequency response Freq(MHz) Cable RL Frequency response 7.9m.1m 1 1 Ω Sdd11 (db) Freq(MHz) Version 1. Broadcom Proprietary & Confidential. 211 Broadcom Corporation. All rights reserved. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 14

15 Eye Diagram for DME Node 2->Node H Channel: Node 2->H (buntz.. Max ) Matched filter output DME No CW Node 2->Node H Matched Filter Output Eye is open Timing offset in ns Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 15

16 Eye Diagram for NRZ Node 2->Node H Channel: Node 2->H (buntz.. Max ) 2 Matched Filter Output NRZ no CW Node 2-> Node H Matched Filter Output Timing offset in ns Version 1. Broadcom Proprietary & Confidential. 211 Broadcom Corporation. All rights reserved. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 16

17 Conclusions Link segments with end termination of 1Ω have low attenuation and don t have deep spectral nulls for frequencies of interest in 1BASE-T1S. DME is spectrally compatible with PoDL and the noise environment of 1BASE- T1S. DME does not require equalization for 1BASE-T1S while NRZ requires an equalizer because of PoDL and low frequency noise. 2Mbps aggregated data rate plus 5Mbps for OAM/control will work fine for 1BASE-T1S, allowing full- duplex point-to-point operation at full 1Mbps line rate without echo cancellation. Version 1. IEEE P82.3 IEEE 82.3cg Maintenance Task Force report December July 2, Plenary Page 17

18 Thank You! Version 1. IEEE 82.3cg Task Force December 2, 217 Page 18