CIF: Medium:Collaborative Research: Explicit Codes for Efficient Operation of

该项目涉及无线多终端网络模型，包括实际约束，如经历衰落的单个链路、延迟敏感的应用程序、受广播和干扰约束的网络通信以及受半双工模式约束的节点。假定网络在消息期间是静态的，但可以从一个消息更改到下一个消息，并且假定通道状态信息仅存在于接收方。在这种情况下，协作通信是网络高效运行的关键，其中中间节点促进特定源-汇对之间的通信。任何通信系统的一个关键目标是实现最佳速率-可靠性权衡。分集-复用增益权衡（DMT）决定了通信速率和可靠性的相关一阶近似之间的权衡。点对点通信链路的DMT已经得到了广泛的研究，并且在衰落信道的任何统计分布下都可以得到最优的信号集。目前已有两跳中继网络的协议和编码，接近于在DMT上实现相应的最小切割上限。本课题的目标包括：1)确定从广播、协同广播、多址信道网络到分层多跳网络等各类多终端网络的DMT；2)识别网络的DMT由最小切割的DMT给出的网络类别；3)评估网络异步运行的影响，以及网络中一个或多个链路上存在的反馈；4)构建解码复杂度较低的编码。

This project deals with models of wireless multi-terminal networks incorporating practical constraints such as individual links that experience fading, applications that are delay-sensitive, network communication that is subject to broadcast and interference constraints and nodes that are constrained to operate in half-duplex mode. The network is assumed to be static for the duration of the message, but can change from one message to the next and channel-state information is assumed to be present only at the receiver. In such settings, cooperative communication in which intermediate nodes facilitate communication between a particular source-sink pair, is key to efficient operation of the network.A key goal of any communication system, is one of achieving an optimal rate-reliability tradeoff. The diversity-multiplexing gain tradeoff (DMT) determines the tradeoff between relevant first-order approximations to the rate and reliability of communication. The DMT of point-to-point communication links has been extensively studied and signal sets are available that are optimal under any statistical distribution of the fading channel. There now exist protocols and codes for two-hop relay networks that come close to achieving the corresponding min-cut upper bound on DMT. Goals of this project include: 1) determining the DMT of various classes of multiterminal networks ranging from broadcast, cooperative-broadcast and multiple-access channel networks to layered multi-hop networks; 2) identifying the classes of networks for which the DMT of the network is given by the DMT of the min-cut; 3) assessing the impact of asynchronous operation of the network, as well as of the presence of feedback along one or more links in the network; 4) the construction of codes with lesser decoding complexity.