Joint multiuser detection and decoding in coded MC-CDMA system : a study on quasi-maximum-likelihood decoding using ordered statistics algorithm

MC - CDMAシステムにおいて,遅延波はコード間干渉を引き起こし,多重ユーザ数が増加するにつれてBER特性を劣化させる。本稿では、符号化MC- CDMAシステムにおいてコード間干渉を軽減するマルチユーザ検出と誤り訂正復号を一体化処理する準最尤検出法において新しい手法を提案する。提案方式では順序統計量復号によって生成された符号語を用いて準最尤検出を行います。提案方式では、受信信号から求めた信頼度を用いた,信頼度の高い符号語のみを考慮します.よって準最尤検出に用いる符号語候補を効果的に削減できる.計算機シミュレーションの結果,提案方式は従来方式よりもすぐれたBER特性を示した.In multi-carrier code division multiple access (MC-CDMA) systems, delay waves cause inter-code interference and degrade bit error rate (BER) performance as the number of multiplexing users increases. In this paper, we propose a new quasi-maximum likelihood detection which jointly performs multiuser detection and error correction decoding for coded MC-CDMA systems to mitigate the inter-code interference. The proposed method uses codewords generated by the ordered statistics decoding for the quasi-maximum likelihood detection. In the proposed method, we only consider the codewords which have relatively high reliability values, where the reliability values are calculated from received signals, so that we can significantly decrease the number of codewords considered in the quasi-maximum likelihood detection. As the result of numerical simulations, we show that the proposed method exhibits better BER performance than a conventional method