The Research Of Hybrid ARQ Protocol In Next Generation Mobile Communication

On the mobile communication systems, a forward error correction (FEC) or automatic repeat request(ARQ ) scheme may be insufficient to achieve the desired performance due to the time-varying nature of the channel. Therefore, the reliability of data and image transmission is usually improved using hybrid ARQ error control scheme which is combined by ARQ and FEC. Hybrid ARQ technique was first designed in the early of 1960s and gains comprehensive research during the latest four decades. Recently, 3GPP has proposed it as one of the most pivotal techniques for the high speed packet transmission.In this paper, research actuality and future progress of Hybrid ARQ are first introduced. The author try to improve the performance of Hybrid ARQ based on Turbo decoding principle,diversity and puncture techniques. Moreover, the paper propose two new Hybrid ARQ protocol: Near invariable transfer delay Hybrid ARQ protocol and A novel Hybrid ARQ protocol with a mix encoder. In this thesis, the author makes the following contributions:1. Introduce the Hybrid ARQ protocol with Turbo code in V-BLAST system, and the Turbo encode and decode algorithm is also listed. Moreover the author gives the simulation result of performance comparison of different Types of Hybrid ARQ with Turbo coder in V-BLAST system.2. Propose Near invariable transfer delay Hybrid ARQ protocol. The new protocol using RCPT (Rate Compatible Punctured Turbo) encoder and decoder in the traditional Hybrid ARQ. And the system could adjust the transfer code rate to math different transfer models according to the requirement. MIMO system with n_T transmit antennas and n_R receive antennas is adopted in the protocol, which can improve the frequency band availability with the increasing of antenna amount. 3. Propose a novel Hybrid ARQ protocol with a mix encoder to reduce hardware loss and decoding delay. The mix encoder takes the advantage of the Turbo encoder structure constituted of two convolutional encoders. The system could choose one of uncode, RCPC or RCPT code as FEC with the feedback information through feedback channel. The protocol used only a pair of Turbo encoder and decoder to accomplish combined FEC, which could reduce hardware loss and cost.