| Presentation | 2008-03-07 Algorithm to Calculate Bit Sequence Log Likelihood Ratio for Coded MIMO-OFDM Suboptimal Detection Jooin WOO, Kazuhiko FUKAWA, Hiroshi SUZUKI, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | This report proposes a low-complexity algorithm to calculate log likelihood ratios (LLRs) of coded bits, which is necessary for channel decoding in coded MIMO-OFDM mobile communications. An approximate calculation of LLR needs to find a pair of transmitted signal candidates that can maximize the log likelihood function with a coded bit equal to either one or zero. The proposed algorithm can find such a pair simultaneously, while conventional ones find them individually. Specifically, the proposed method searches such candidates in the directions of the noise enhancement using the MMSE detection as a starting point. First, the inverse matrix of the autocorrelation matrix of received signal is obtained and then the power method derives eigenvectors of the inverse matrix as the directions of the noise enhancement. With each eigenvector, one-dimensional search and hard decision are performed. From the resultant signals, the transmitted signal candidates to be required are selected on the basis of the log likelihood function. Computer simulations with 4×4 MIMO-OFDM, QPSK, and the convolutional code of coding rate 1/2 demonstrate that the proposed algorithm requires only 0.6dB more E_b/N_0 than that of the maximum likelihood detection (MLD) in order to achieve PER of 10^<-3>, while reducing the complexity to about 12.5% of that of MLD. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Mobile communication / MIMO-OFDM / channel coding / log likelihood ratio / MMSE detection / noise enhancement / power method |
| Paper # | RCS2007-232 |
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| Conference Information | |
| Committee | RCS |
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| Conference Date | 2008/2/27(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) | Algorithm to Calculate Bit Sequence Log Likelihood Ratio for Coded MIMO-OFDM Suboptimal Detection |
| Sub Title (in English) | |
| Keyword(1) | Mobile communication |
| Keyword(2) | MIMO-OFDM |
| Keyword(3) | channel coding |
| Keyword(4) | log likelihood ratio |
| Keyword(5) | MMSE detection |
| Keyword(6) | noise enhancement |
| Keyword(7) | power method |
| 1st Author's Name | Jooin WOO |
| 1st Author's Affiliation | Tokyo Institute of Technology() |
| 2nd Author's Name | Kazuhiko FUKAWA |
| 2nd Author's Affiliation | Tokyo Institute of Technology |
| 3rd Author's Name | Hiroshi SUZUKI |
| 3rd Author's Affiliation | Tokyo Institute of Technology |
| Date | 2008-03-07 |
| Paper # | RCS2007-232 |
| Volume (vol) | vol.107 |
| Number (no) | 518 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |