| 研究実績の概要 |
We further revised the our spatially coupled repeat-accumulate-repeat (SC-RA-R) codes by simply adjusting the parameters in the repeat component code, which determine repeat times and corresponding repeat proportion of systematic and parity bits at each coupling position of the outer code, respectively. Thus the proposed codes, called as multi-user rate-less SC-RA-R codes, can provide any sum-rate for the IDMA systems, while with the same implementations of encoder and decoder. The numerical result of the EXIT analysis show that the proposed codes are close to Shannon bound for arbitrary sum rate regions at various numbers of user K, and outperform the two conventional codes. These results show that the proposed spatially coupled codes are universal codes that have capacity-approaching performance on various communication scenarios, such as various numbers of users and various channel conditions.
Moreover, we apply the spatial coupling concept to random access system, and propose a framed spatially-coupled coded slotted ALOHA (f-SCCSA) system. We analyze the decoding performance of the systems, and show it approaches the theoretic limit, even with a finite-length packet transmission.
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