Advanced Coding Comparison Month 2000 doc.: IEEE 802.11-00/xxx March 2005 Advanced Coding Comparison Marie-Helene Hamon, John Benko France Telecom Claude Berrou ENST Bretagne Jacky Tousch TurboConcept Brian Edmonston iCoding John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

Outline Coding proposals in TGn Advanced FEC Code Requirements for TGn Month 2000 doc.: IEEE 802.11-00/xxx March 2005 Outline Coding proposals in TGn Advanced FEC Code Requirements for TGn Comparing Codes LDPCC vs. Turbo Codes Facts & Recommendations John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

Coding Proposals in TGn (Historical) Month 2000 doc.: IEEE 802.11-00/xxx March 2005 Coding Proposals in TGn (Historical) Partial (13): Nokia LDPC Infocomm Research LDPC ST Micro LDPC Nortel LDPC Panasonic LDPC Hughes LDPC Inprocomm LDPC Sharp 7/8 CC Philips Concatenated RS Trellisware Hybrid LDPC/TurboCode France Telecom Turbo Code Motorola Turbo Code Wwise Turbo Code Full: TGnSync LDPC Optional Wwise LDPC Optional MitMot Turbo Code Optional Qualcomm None John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

Advanced FEC Code Requirements Month 2000 doc.: IEEE 802.11-00/xxx March 2005 Advanced FEC Code Requirements Performance Much better than 802.11a CC Must have good performance for all blocksizes (small as well as large) Small blocksize example: VoIP packets (as small as 50 bytes) Large blocksize example: Streaming HD-Video Latency Low, < 6 us Good performance with a small number of iterations Implementation Low Cost – small die size (memory and logic) Mature, 802.11 – Chipsets require fast time to market Should not be held up due to a FEC without a well-defined implementation John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

ST-Micro (Wwise)* LDPCC vs. TC Month 2000 doc.: IEEE 802.11-00/xxx March 2005 ST-Micro (Wwise)* LDPCC vs. TC SISO AWGN BPSK+ N=1744 bits Wwise LDPCC -972 bits (121.5 bytes) 12i => 600kGates, 6 us Duo-Binary TC -976 bits (122 bytes) 8i, P=12 => 2.0 mm2, 5.12 us TGnSync LDPCC -Equivalent not found *Wwise Results from Berlin presentation [1] +BPSK, R=1/2 proposed as optional mode in Wwise John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

Wwise LDPCC*, TC and CC 2x2 SDM, AWGN 64-QAM, R=3/4 March 2005 Wwise LDPCC*, TC and CC 2x2 SDM, AWGN 64-QAM, R=3/4 Gains over CC @ 10-2 PER TC : ~3.2 dB (8 iterations) LDPCC: ~2.4 dB TC LDPCC CC *Wwise Results taken from [2] John Benko, Marie-Helene Hamon, France Telecom

LDPCC from .16e* AWGN, QPSK, R=1/2 TC Gains over LDPCC@ 10-2 PER March 2005 LDPCC from .16e* AWGN, QPSK, R=1/2 LDPCC - 50 iterations (unrealistic) TC - 8 iterations (realistic) TC Gains over LDPCC@ 10-2 PER N=2304: 0.2 dB N=576 : 0.3 dB (increase with smaller block size) TC LDPCC TC LDPCC *LDPCC here [3] is slightly different from what is used in TGnSync John Benko, Marie-Helene Hamon, France Telecom

Complexity Comparison Month 2000 doc.: IEEE 802.11-00/xxx March 2005 Complexity Comparison Chip Area Number of Gates Technology used (ex. ASIC 0.13 mm, average density of 222 kgates/mm2) Degree of Parallelism (relates also to max decoded bit-rate) Latency < 6 ms Number of Iterations Degree of Parallelism Clock Frequency used (typical Fclk=200 MHz) *Estimates from [4] +Estimates from [2] Code Max Encoded Block Size FclkMHz P Nit Total Memory Decoded Rate(Max) Max Latency Area (.13 mm) Turbo Code* duo-binary 2048 bits 200 8 5 59 kbits 320 Mbps 4.8 ms 1.4 mm2 12 68 kbits 480 Mbps 3.2 ms 2.0 mm2 200 Mbps 5.12 ms Wwise LDPC+ 1944 bits 240 ? 300 Mbps 6.0 ms Sync LDPC 1728 bits John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

LDPCCs vs. Turbo Codes (TCs) March 2005 LDPCCs vs. Turbo Codes (TCs) LDPCCs History Discovered in 60’s by Gallager -Implemented only in past few years -Original Patent expired, but -Since March 2001, 152 Patents have been applied for/ granted concerning LDPCCs [5] Technology New Development -Hot Research Topic at many universities -No common implementation available Performance* Improves as the block size increases TCs Discovered in early 90’s by Berrou, et al. -Patents exist, but -Well defined licensing program Mature, Stable -Well established & implemented -Ongoing Research at select universities - Turbo Decoders are already available (Implementation targeted for ASIC, but also FPGA) Good performance for all .11n block sizes (given latency requirements) *Generalization John Benko, Marie-Helene Hamon, France Telecom

Facts & Recommendations Month 2000 doc.: IEEE 802.11-00/xxx Facts & Recommendations March 2005 Modularity Performance of the FEC code is independant of system Codes proposed can be easily put in WWise and TGnSync Difficult to compare From FRCC, code performance seen only in context of full system Current two proposed specfications differ Wwise nor TGnSych provided simulation results for their code with other proposal Codes compared in performance should be of similar complexity Very little complexity results have been seen to this date Mature code Enables pre and 1st production devices to ship with advanced coding options. Action Item? We need to re-think(create) the advanced coding selection process or we might get stuck with an advanced coding scheme that is not in the best interest of the 802.11n Suggestion: Form a separate coding sub-group John Benko, Marie-Helene Hamon, France Telecom John Doe, His Company

March 2005 References [1] IEEE 802.11-04/400r4, " ST Microelectronics LDPCC Partial Proposal for 802.11n CFP”, ST Micro, September 2004. [2] IEEE 802.11/04-0877-08-000n, “WWiSE proposal response to functional requirements and comparison criteria.” [3] IEEE 802.16e-0/006,  " LDPC Coding for OFDMA PHY", January 2005. [4] IEEE 802.11-04/1382r1, "Turbo Codes: Complexity Estimates", TurboConcept France Telecom R&D, November 2004. [5] http://www.uspto.gov [6] C. Berrou, A. Glavieux, P. Thitimajshima, "Near Shannon limit error-correcting coding and decoding: Turbo Codes", ICC93, vol. 2, pp. 1064-1070, May 93. [7] C. Berrou, "The ten-year-old turbo codes are entering into service", IEEE Communications Magazine, vol. 41, pp. 110-116, August 03. [8] C. Berrou, M. Jezequel, C. Douillard, S. Kerouedan, "The advantages of non-binary turbo codes", Proc IEEE ITW 2001, pp. 61-63, Sept. 01. John Benko, Marie-Helene Hamon, France Telecom