2007 Fiscal Year Final Research Report Summary
Development of Nonbinary Communication Systems Approaching Shannon Limit by Using PA Codes
| Project/Area Number |
18560367
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Communication/Network engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
UYEROATSU Tomohiko Tokyo Institute of Technology, Dept. of Communications and Integrated Systems, Professor (60168656)
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| Co-Investigator(Kenkyū-buntansha) |
SAKANIWA Kohichi Tokyo Institute of Technology, Dept. of Communications and Integrated SysiErns, Professor (30114870)
MATSUMOTO Ryutaroh Tokyo Institute of Technology, Dept. of Communications and Integrated Systems, Associate Professor (10334517)
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| Project Period (FY) |
2006 – 2007
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| Keywords | PA code / multilevel modulation / Shannon limit |
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| Research Abstract |
PA (Product Accumulate) axles achieve performance close to the Shannon limit for BPSK (Binary Phase Shill Keying) with low encoding and decoding complexity. This research proposes methods for application of PA axles to multilevel modulation by using MLC (Multilevel Coding) and BICM-ID (Bit-Interleaved Coded Modulation with Iterative Decoding), and obtained the following results.
1. In order to design the rate of PA code flexibly, we investigate performances of PA and GPA (Generalized Product Accumulate) codes which consist of some different single parity check codes. Computer simulation reveals the required signal-to-noise ratio such that the probability of decoding error vanishes as the block length of the codes tends to infinity.
2. We clarify the labeling method that gives the lowest decoding error probability for BICM-ID and MLC. Gray mapping is optimum for BICM-ID, while Ungerboeck mapping is optimum for MLC.
3. Computer simulation demonstrates that MLC and BICM-ID system give performances close to the Shannon limit for 4-ASK (Amplitude Shift Keying), 8-ASK, and 8-PSK. More specifically, in order to achieve the probability of decoding error 10-5, the required signal-to-noise ratio for BICM-ID is within 1.2〜1.5dB away from the Shannon, while the required signal-to-noise ratio for MLC is within 1.0〜1.3dB away from the Shannon limit.
4. We establish the design method of high performance PA codes for 4-ASK, 8-ASK and 8-PSK.
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