Turbo Multiuser Detection: Analysis, Optimization and Applications

目的和意义：Turbo原理[27]，即利用通信接收器中不同块之间的软信息的迭代交换的策略，已经成长为解决通信中的各种问题的有力工具。尤其是Turbo多用户检测(MUD)范例[59]作为多用户通信系统中联合译码的有效技术而引起了显著的关注。然而，到目前为止，各种Turbo MUD方案的性能主要通过模拟来展示，以及Turbo MUD对网络性能的影响(例如，目前还不清楚如何设计上层功能(如ARQ协议、功率控制和接纳控制)来开发物理层Turbo MUD。所提出的项目的目标是开发分析工具来评估和优化各种Turbo MUD方法的性能，并将这些结果应用于无线网络中的C-OSS层设计。最近，在编码界已经开发了一种称为密度进化[66，67]的技术，该技术允许在Nite长度的码字中分析迭代译码算法。在该方案中，在密度进化框架下，我们概述了一个研究计划，旨在了解在各种信道条件和接收器结构下Turbo多用户检测的设计和分析，以及考虑物理层Turbo MUD的一些上层功能的设计。虽然在本研究中我们专注于多用户码分多址系统，但其一般原理适用于多种系统，如空时编码系统、ofdm系统和码间干扰系统。

Wang, XiaodongColumbia UniversityObjectives and Significance: The turbo principle [27 ],namely,the strategy that exploits the iteratedexchange of soft information between di .erent blocks in a communication receiver,has grown to be a powerfultool in attacking a diverse set of problems in communications.In particular,the turbo multiuser detection(MUD)paradigm [59 ]has attracted signi .cant recent attention as an e .ective technique for joint decodingin multiuser communication systems.However to date the performance of various turbo MUD schemesis largely demonstrated via simulations,and the impact of turbo MUD on the network performance (e.g.,throughput and delay)has not been explored systematically.It also remains unclear at this time how theupper-layer functionalities (such as ARQ protocol,power control,and admission control)should be designedto exploit the physical-layer turbo MUD.The objective of the proposed project is to develop analytical tools toassess and optimize the performance of various turbo MUD methods,and to apply these esults to c oss-layerdesign in wireless networks.Recently a technique known as density evolution [66,67 ]has been developed in the coding community thatpermits analysis of iterative decoding algorithm for in .nite-length codewords.In this proposal,under thedensity evolution framework,we outline a research plan aimed at understanding of the design and analysis ofturbo multiuser detection for a variety of channel conditions and receiver structures,and the design of someupper-layer functionalities which takes into account the physical layer turbo MUD.While in this study wefocus on multiuser CDMA systems,the general principle is applicable to several systems,such as space-timecoding systems,OFDM systems,and intersymbol interference systems.