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

该项目涉及包含实际约束的无线多终端网络模型，例如经历衰落的个别链路、对延迟敏感的应用、受广播和干扰约束的网络通信以及被约束在半双工模式下运行的节点。假定网络在消息的持续时间内是静态的，但可以从一条消息改变到下一条消息，并且假定信道状态信息仅存在于接收方。在这种情况下，中间节点促进特定信源-信宿对之间的通信的协作通信是网络有效运行的关键。任何通信系统的关键目标之一是实现最优的速率-可靠性折衷。分集-复用增益权衡(DMT)决定了相关一阶近似与通信速率和可靠性之间的权衡。点对点通信链路的DMT已经被广泛研究，并且可以得到在衰落信道的任何统计分布下都是最优的信号集。现在存在两跳中继网络的协议和代码，这些协议和代码接近于实现DMT上的相应最小截断上限。该项目的目标包括：1)确定从广播、合作广播和多址接入信道网络到分层多跳网络的各种类型的多终端网络的DMT；2)确定网络的DMT由最小割的DMT给出的网络类别；3)评估网络的异步操作的影响，以及网络中沿一条或多条链路的反馈的存在；4)构造译码复杂度较低的码。

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.