Doc.: IEEE 802.15-01/448r0 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Trellis Coding for QPSK, 16/32/64-QAM Transmission modes Date.

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Transcript Doc.: IEEE 802.15-01/448r0 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Trellis Coding for QPSK, 16/32/64-QAM Transmission modes Date.

Doc.: IEEE 802.15-01/448r0 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title:

Trellis Coding for QPSK, 16/32/64-QAM Transmission modes

Date Submitted:

12 October 2001

Source:

Jeyhan Karaoguz

Address:

Broadcom Corporation, 16215 Alton Parkway, Irvine, CA 92619

Voice:

949 585 6168

E-Mail:

[email protected]

Re: Abstract:

This proposal describes an 8-State Trellis Code suitable for QPSK, 16/32/64-QAM transmission modes delivering 11, 33, 44, 55 Mbps.

Purpose: Notice:

This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

Release:

The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15

10/12/2001

Signal Constellations

Doc.: IEEE 802.15-01/448r0 64-QAM TCM (55 Mbit/s) 32-QAM TCM (44 Mbit/s) 16-QAM TCM (33 Mbit/s) QPSK (22 Mbit/s uncoded, 11 Mbit/s coded )

2 Jeyhan Karaoguz, Broadcom Corporation

Doc.: IEEE 802.15-01/448r0 10/12/2001

QPSK, 16/32/64-QAM Set Partitioning

8 d 16, 32, 64-QAM Set Partitioning 2 d 4 d d D0 D4 D2 QPSK Set Partitioning D6 d D1 D5 D3 D7 D0 D2

3

D1 D3

Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

8-State Multi-Rate TCM Encoder

b 4 b 3 b 2 b 1 b o 1,3,4,5 bits/symbol (=0 for QPSK)

T

+

T

+

T

Symbol Selection from Subsets 64-QAM 32-QAM 16-QAM QPSK Subset Selection (D0,…,D7)

QPSK, 16/32/64 QAM TCM Mode Selection 2-D Output to Pulse Shaping Filter 4 Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

Trellis State Transitions for 16,32,64 QAM

D0 D2 D4 D6 D5 D7 D1 D3 D2 D0 D6 D4 D7 D5 D3 D1 D4 D6 D0 D2 D1 D3 D5 D7 D6 D4 D2 D0 D3 D1 D7 D5

Minimum distance error event occurs between code sequences

D0-D0-D0

and

D2-D1-D6

Squared Euclidean distance between these sequences:

2d 2 +d 2 +2d 2 = 5d 2

Approximate coding gain:

10log(5/2) = 4 dB

5 Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

Trellis State Transitions for QPSK

S0 S1 S2 S3 S4 S5 S6 S7 D0 D2 D1 D3 D2 D0 D3 D1 D0 D2 D1 D3 D2 D0 D3 D1

Minimum distance error event occurs between code sequences:

D0-D0-D0-D0

and

D2-D1-D0-D2

Squared Euclidean distance between these sequences:

2d 2 + d 2 + 0+ 2d 2

Approximate coding gain:

10log(5/2) = 4 dB (compared to uncoded BPSK)

6 Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

Optimal 8-State Multi-Rate TCM Encoder

b 4 b 3 b 2 b 1 b o 1,3,4,5 bits/symbol (=0 for QPSK)

T

+

T

+

T

Symbol Selection from Subsets 64-QAM 32-QAM 16-QAM QPSK Subset Selection (D0,…,D7)

QPSK, 16/32/64 QAM TCM Mode Selection 2-D Output to Pulse Shaping Filter 7 Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

Optimal Trellis State Transitions for QPSK

D0 D2 D1 D3 D2 D0 D3 D1 D0 D2 D1 D3 D2 D0 D3 D1

Minimum distance error event occurs between code sequences:

D0-D0-D0-D0-D0

and

D2-D1-D3-D0-D2

Squared Euclidean distance between these sequences:

2d 2 + d 2 + d 2 + 0+ 2d 2

Approximate coding gain:

10log( 6/3) = 4.8 dB (compared to uncoded BPSK)

8 Jeyhan Karaoguz, Broadcom Corporation

Doc.: IEEE 802.15-01/448r0 10/12/2001

Receiver Sensitivity

•

Receiver Sensitivity: AWGN 14 MHz BW + Noise Figure (15 dB) + SNR 10 -5 BER

– -68 dBm for 64-QAM TCM, 55 Mbit/sec – -71 dBm for 32-QAM TCM, 44 Mbit/sec – -74 dBm for 16-QAM TCM, 33 Mbit/sec – -75 dBm for QPSK (uncoded), 22 Mbit/sec – -78 dBm for BPSK (uncoded), 11 Mbit/sec – -82 dBm for QPSK-TCM (optimal code), 11 Mbit/sec 9 Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

Comparison of SNR Requirements

•

Operating at 10

-5

BER

– 22 Mbps uncoded QPSK modulation requires 12.6 dB SNR – 11 Mbps uncoded BPSK modulation requires 9.6 dB SNR – 11 Mbps QPSK-TCM modulation requires 5.5 dB SNR •

When uncoded QPSK operates at 10

-5

BER

– 11 Mbps uncoded BPSK achieves 10 -9 BER – 11 Mbps QPSK-TCM achieves 10 -21 BER 10 Jeyhan Karaoguz, Broadcom Corporation

10/12/2001 Doc.: IEEE 802.15-01/448r0

Header and Payload Coding

22, 33, 44, 55 Mbps (QPSK, 16/32/64-QAM TCM) Transmission Modes

Header (MAC+PHY)

QPSK

Payload

QPSK, 16/32/64-QAM TCM 11 Mbps QPSK-TCM Transmission Mode

Header (MAC+PHY) Repeat Header (MAC+PHY)

QPSK QPSK-TCM

Payload

QPSK-TCM

11 Jeyhan Karaoguz, Broadcom Corporation

Doc.: IEEE 802.15-01/448r0 10/12/2001

Conclusions

•

Use of QPSK-TCM for 11 Mbps transmission mode allows the same signal constellation used in the base QPSK mode

– No mention of BPSK signalling, constellation, EVM spec, etc. •

Same 8-State TCM code is used for transmission modes 11, 33, 44, 55 Mbps

•

QPSK-TCM achieves 4 dB more coding gain compared to 11 Mbps uncoded BPSK modulation

12 Jeyhan Karaoguz, Broadcom Corporation

Doc.: IEEE 802.15-01/448r0 10/12/2001

References

•

“Channel Coding with Multilevel/Phase Signals”, G. Ungerboeck,

IEEE Transactions on Information Theory, January 1982

13 Jeyhan Karaoguz, Broadcom Corporation