In this paper, we present new results on the search and determination of wide-sense convolutional self-doubly orthogonal codes ((CSOC)-C-2-WS) which can be decoded using a simple iterative threshold decoding algorithm...
详细信息
In this paper, we present new results on the search and determination of wide-sense convolutional self-doubly orthogonal codes ((CSOC)-C-2-WS) which can be decoded using a simple iterative threshold decoding algorithm without interleaving. For their iterative decoding, in order to ensure the independence of observables over the first two iterations without the presence of interleavers, these (CSOC)-C-2 must satisfy specific orthogonal properties of their generator connections. The error performances of (CSOC)-C-2, depend essentially on the number of taps J of the code generators but not on the code memory length. Since the overall latency of the iterative threshold decoding process is proportional to the memory length of the codes, therefore, when searching for the best (CSOC)-C-2-WS of a given J value, the memory length of the codes should be chosen to be as small as possible. In this paper, we present a code-searching technique based on heuristic computer searching algorithms which have yielded the best known (CSOC)-C-2-WS. The construction method for (CSOC)-C-2-WS has provided the best known r = 1/2 codes with the shortest memory length having J ≤ 30. Although not very complex to implement, the search method presented here is quite efficient especially in reducing very substantially the execution time required to determine the codes with the shortest spans. Furthermore, in addition to presenting the search results for the codes, error performances obtained by simulation are also provided.
In this paper we present an efficient algorithm to search for optimal/short-span Convolutional Self-Doubly Orthogonal codes ((CSOC)-C-2) using a novel parallel exhaustive-search algorithm. The error correcting codes a...
详细信息
ISBN:
(纸本)9781424416424
In this paper we present an efficient algorithm to search for optimal/short-span Convolutional Self-Doubly Orthogonal codes ((CSOC)-C-2) using a novel parallel exhaustive-search algorithm. The error correcting codes are used in the new (CSOC)-C-2 encoding/iterative threshold decoding technique that was introduced as an alternative to Turbo codes. Since the iterative threshold decoding algorithm does not use interleaving, the generator connections in these codes must satisfy specific orthogonality properties to ensure the independence of observables over the first two iterations. The code constraint length (or "span" of the code) corresponds to the latency of each decoding iteration, and minimizing it for a given error-correcting capability is important when building high-performance, low-latency codecs. The proposed algorithm drastically speeds up the implicitly-exhaustive search for shorter-spancodes and scales well on today's multi-core computer systems. On a 16-core server, the computational time for obtaining optimal J=6 and J=7 (CSOC)-C-2 was reduced by 93%.
暂无评论