1. Turbo Codes for IEEE 802.11n May 2004
March 2004
May 2004
Turbo Codes for IEEE n
May 2004
Marie-Helene Hamon, Vincent Le Nir, Marilyne Helard
France Telecom R&D, Rennes, France
Brian Edmonston, iCoding
(contact:
France Telecom R&D

2. Contents TC for 802.11n Duo-Binary Turbo Codes Simulation assumptions
March 2004
May 2004
Contents
TC for n
Duo-Binary Turbo Codes
Simulation assumptions
Results
Conclusion
France Telecom R&D

3. Turbo Codes: Iterative FEC for 802.11n
March 2004
May 2004
Turbo Codes: Iterative FEC for n
Powerful error correcting codes are considered in n discussions
Turbo Codes, and more specifically Duo-Binary Turbo Codes [4], the latest generation of convolutional turbo codes, have been introduced in contribution IEEE /003 [1] at the last meeting
The numerous advantages of these Turbo Codes, including the large performance gains enabled and their high flexibility, have been demonstrated in this previous contribution. This presentation will focus on the performance of these Turbo Codes in a PHY reference model.
France Telecom R&D

4. Duo-Binary Turbo Codes
May 2004
Duo-Binary Turbo Codes
Very good performance: better than LDPC codes
- for any code rate
- for any block size <10000 bits
- for any BER >10-9
- for any associated modulation
Highly flexible solution: Duo-Binary Turbo Codes adjust easily to any code rate and block size, resulting in a better granularity

5. Simulation assumptions
May 2004
Simulation assumptions
Simulation chain based on a PHY model
Perfect channel estimation, synchronization and front end (SISO configuration)
Channels
- AWGN channel
- BRAN A channel

6. Simulation Assumptions
May 2004
Simulation Assumptions
The turbo code and the a convolutional code both simulated, with packet size 200 bytes, code rates ½ and ¾
Turbo Codes
- 8-state Duo-Binary Convolutional Turbo Codes
- Max-Log-MAP decoding, 8 iterations
Convolutional Code
- Viterbi decoding algorithm

7. Simulation Results: AWGN
May 2004
Simulation Results: AWGN
2 to 2.5 dB gain
at PER 1%

8. Simulation Results: BRAN A
May 2004
Simulation Results: BRAN A
1.8 to 2.4 dB gain
at PER 1%

9. May 2004
Turbo Codes and MIMO
MIMO techniques employed: Space-Time Block Coding (2x1) Alamouti scheme
Channel model: uncorrelated Rayleigh fading channels

10. Simulation results: STBC 2x1
May 2004
Simulation results: STBC 2x1

11. May 2004
Conclusions
Turbo Codes, and more specifically Duo-Binary Turbo Codes, provide large performance gains in a context, as well as combined with MIMO techniques
Their flexibility is an important advantage, allowing a finer granularity in block size and coding rate (cf [1])
Incorporated in a complete system, these Turbo Codes will represent a significant advantage to achieve n goals.

12. May 2004
References
[1] IEEE /003, "Turbo Codes for n", France Telecom R&D, ENST Bretagne, iCoding Technology, TurboConcept, January 2004.
[2] C. Berrou, A. Glavieux, P. Thitimajshima, "Near Shannon limit error-correcting coding and decoding: Turbo Codes", ICC93, vol. 2, pp , May 93.
[3] C. Berrou, "The ten-year-old turbo codes are entering into service", IEEE Communications Magazine, vol. 41, pp , August 03.
[4] C. Berrou, M. Jezequel, C. Douillard, S. Kerouedan, "The advantages of non-binary turbo codes", Proc IEEE ITW 2001, pp , Sept. 01.
[5] TS : 3rd Generation Partnership Project (3GPP) ; Technical Specification Group (TSG) ; Radio Access Network (RAN) ; Working Group 1 (WG1); "Multiplexing and channel coding (FDD)". October 1999.
[6] EN : Digital Video Broadcasting (DVB) "Interaction channel or satellite distribution systems". December 2000.
[7] EN : Digital Video Broadcasting (DVB) "Specification of interaction channel for digital terrestrial TV including multiple access OFDM". March 2002.

13. BRAN A Channel SISO WLAN channel model
May 2004
BRAN A Channel
SISO WLAN channel model
Delay profile model, typical office environment, NLOS
50 ns rms delay spread
18 taps, max delay spread 390 ns