| Presentation | 2004-06-18 A Comparison of LDPC Codes and Turbo Codes over Frequency Selective Fading Channels in Broadband OFDM System Makoto YOSHIDA, Chikara KOJIMA, Atsuhiko SUGITANI, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | In this paper, we make performance comparisons between LDPC (Low-Density Parity-Check) codes and turbo codes in an OFDM (Orthogonal Frequency Division Multiplexing) system on frequency selective fading channels. On frequency selective fading channels, coherent bandwidth depends on delay spread of the channel. In an OFDM system, when coherent bandwidth is large, correlation between adjacent subcarriers is also large and causes burst errors in the frequency-domain. Therefore performances of turbo codes, which are used for random error channels, are degraded in such a condition. To suppress these degradations, burst errors are randomized by using a channel interleaver. On the other hand, LDPC codes have a natural interleaving mechanism and do not require the channel interleaver independent of channel conditions. We show that an OFDM system using turbo codes need a random interleaver as a channel interleaver in order to remove the influence of the delay spread, while an OFDM system using LDPC codes without a channel interleaver keeps constant independent of the delay spread. Moreover, LDPC codes, which are capable of parallel decoding processing, can realize faster decoder than for Turbo codes. Therefore, LDPC is a promising technique for next generation mobile communications systems required for high speed transmission. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | LDPC codes / Turbo codes / OFDM / Frequency selective fading channels |
| Paper # | RCS2004-76 |
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| Committee | RCS |
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| Conference Date | 2004/6/11(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Topics (in Japanese) | (See Japanese page) |
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| Registration To | Radio Communication Systems (RCS) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | A Comparison of LDPC Codes and Turbo Codes over Frequency Selective Fading Channels in Broadband OFDM System |
| Sub Title (in English) | |
| Keyword(1) | LDPC codes |
| Keyword(2) | Turbo codes |
| Keyword(3) | OFDM |
| Keyword(4) | Frequency selective fading channels |
| 1st Author's Name | Makoto YOSHIDA |
| 1st Author's Affiliation | Fujitsu Limited() |
| 2nd Author's Name | Chikara KOJIMA |
| 2nd Author's Affiliation | Mobile Techno Corporation |
| 3rd Author's Name | Atsuhiko SUGITANI |
| 3rd Author's Affiliation | Mobile Techno Corporation |
| Date | 2004-06-18 |
| Paper # | RCS2004-76 |
| Volume (vol) | vol.104 |
| Number (no) | 123 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |