1. Advanced Coding Comparison
Month 2000
doc.: IEEE /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

2. Outline Coding proposals in TGn Advanced FEC Code Requirements for TGn
Month 2000
doc.: IEEE /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

3. Coding Proposals in TGn (Historical)
Month 2000
doc.: IEEE /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

4. Advanced FEC Code Requirements
Month 2000
doc.: IEEE /xxx
March 2005
Advanced FEC Code Requirements
Performance
Much better than a 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, – 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

5. ST-Micro (Wwise)* LDPCC vs. TC
Month 2000
doc.: IEEE /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

6. 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 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

7. 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 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

8. Complexity Comparison
Month 2000
doc.: IEEE /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

9. 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

10. Facts & Recommendations
Month 2000
doc.: IEEE /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 n
Suggestion: Form a separate coding sub-group
John Benko, Marie-Helene Hamon, France Telecom
John Doe, His Company

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