基于RCPT编码的自适应选择合并混合ARQ算法

Adaptive selective combining Hybrid ARQ based on RCPT codes

摘要:

混合自动重传请求(ARQ)作为一种差错控制技术被采纳为3GPP长期演进项目(LTE)的关键技术。基于速率兼容截断Turbo(RCPT)编码的混合ARQ算法，因其性能优异、实现复杂度低而被广泛关注。传统混合ARQ算法主要包括Chase合并方式混合ARQ，其在高信噪比条件下提供较大的性能增益；以及增量冗余(IR)方式混合ARQ，其在低信噪比条件下提供了更精确的速率控制。本文结合现有方法提出了一种基于RCPT编码的自适应选择合并混合ARQ算法，它在不同信噪比条件下自适应地选择Chase合并方式混合ARQ与IR方式混合ARQ，并且在接收端自适应地选择合并可靠性较高的传输码块。本文对其在瑞利衰落信道中的性能作了理论分析，并且进行了仿真，同时与传统的Chase合并方式混合ARQ以及IR方式混合ARQ作了性能比较。比较结果显示本文的算法在瑞利信道中比传统算法具有更为优异的性能以及相似的复杂度。

Abstract:

Hybrid Automatic Repeat reQuest(Hybrid ARQ) which is an excellent error control technique has been accepted as a key technique of 3GPP Long Term Evolution(LTE). Hybrid ARQ scheme based on Rate Compatible Punctured Turbo(RCPT) codes has outstanding performance and low implementation complexity, therefore this scheme has attracted wide concern. Traditional Hybrid ARQ schemes consist of Chase Combining based Hybrid ARQ(CC-HARQ) which has greater performance gain under higher channel SNR; and IR(Incremental Redundancy) based Hybrid ARQ which provides precise rate control under lower channel SNR. This paper proposes an Adaptive Selective Combining Hybrid ARQ(ASC-HARQ) which adaptively chooses CC-HARQ or IR-HARQ according to different channel SNR, while the receiver adaptively combines selected code blocks with high reliability. This paper analyzes the scheme’s performance in Rayleigh fading channel. Simulation results are given to compare the performance of this novel scheme with that of CC-HARQ and IR-HARQ. According to the simulation results, this scheme performs better than traditional schemes with similar complexity.