November 1999

Alantro Communications and SharewaveSlide 1

doc.: IEEE 802.11-99/250

Submission

Reed-Solomon Codingfor IEEE 802.11

• Chris Heegard & Matthew Shoemake– Alantro Communications

• Rajugopal Gubbi– Sharewave

November 1999

Alantro Communications and SharewaveSlide 2

doc.: IEEE 802.11-99/250

Submission

Presentation Slide 1 Dr. Rajugopal Gubbi

Nov. 1999 IEEE P802.11-99/

FEC for Streams

• All streams can not be treated in the same way at MAC

• Different streams have different transmission requirements. Eg.,

• High bandwidth requirement for stream like video prohibit

retransmissions.

• Latency constraints in streams like voice limits the number of

retransmissions attempts.

• Other streams like audio, interactive media have different

retransmission requirements

• Error correction significantly improves the data throughput.

November 1999

Alantro Communications and SharewaveSlide 3

doc.: IEEE 802.11-99/250

Submission

Presentation Slide 2 Dr. Rajugopal Gubbi

Nov. 1999 IEEE P802.11-99/

Feasibility of Reed Soloman Coder

• Well known technology

• Already used by standards

• IEEE 802.14/MCNS

• DVB/DBS

• Etc...

• Commercially available

• RS (255, 239), tmax=8 cores are under 20K gates

November 1999

Alantro Communications and SharewaveSlide 4

doc.: IEEE 802.11-99/250

Submission

Presentation Slide 3 Dr. Rajugopal Gubbi

Nov. 1999 IEEE P802.11-99/

FEC Field Results

x1

x3

x5

x7

x9

0x1x

2x3x

4x5x

6x7x

8x9x

0

5

10

15

20

25

30

PER [%]

Un corrected PER242.4 K Packet Cluster

x1

x3

x5

x7

x9

0x1x

2x3x

4x5x

6x7x

8x9x

Corrected PER242.4 K Packet Cluster

Before FEC After FEC* 4 sq. /ft MatrixTest Area* 45ft Transmit Distance

November 1999

Alantro Communications and SharewaveSlide 5

doc.: IEEE 802.11-99/250

Submission

Parameters of Reed-Solomon Codes forMPEG Video Packets

• GF256 (8 bit byte symbols)

• (n <= 257, k = n-2*t, d = 2*t+1)– Can correct t errors

• MPEG-2 Packets, k = 188, n = 188+2*t

November 1999

Alantro Communications and SharewaveSlide 6

doc.: IEEE 802.11-99/250

Submission

CCK at 11 Mbps, Es/No

November 1999

Alantro Communications and SharewaveSlide 7

doc.: IEEE 802.11-99/250

Submission

PBCC at 11 Mbps, Es/No

November 1999

Alantro Communications and SharewaveSlide 8

doc.: IEEE 802.11-99/250

Submission

CCK at 11 Mbps, Eb/No

November 1999

Alantro Communications and SharewaveSlide 9

doc.: IEEE 802.11-99/250

Submission

PBCC at 11 Mbps, Eb/No