Collaborative Research: Distributed Error Correction Strategies in Wireless Networks

通过多跳的网络化无线通信正迅速成为未来无线系统的主要架构，包括蜂窝和WiFi网络、网状网络和传感器网络的多跳扩展。这些类型的网络的共同之处在于，它们不是完全非结构化的（或自组织的）网络，而是将流量路由到共同的目的地并进行累积。由于这种特性，这些网络将被称为具有流量累积的网络或NETA。由于流量负载和干扰的增加，流量积累会在公共目的地周围产生热点或瓶颈。尽管热点问题的严重性，有没有有效的方法来科普它。本研究通过开发新的分布式错误校正策略，适合两个重要的子类-线网络和树网络的NETA热点问题。在线网络中，研究人员研究的基本属性和分布式信道编码协议的设计，使用串行级联和protograph为基础的建设，以加强在目的地附近的纠错能力，而不牺牲badwidth效率。在树形网络中，若干源节点可能希望采用公共中继节点来将它们的信息广播到多个目的地节点，这些目的地节点可以访问来自“偷听到的”源消息的边信息。研究人员探索了一种新的方法，其中每个源使用不同的低速率代码传输到中继，而解码的消息使用高速率“嵌套代码”重新编码。此外，考虑了层间问题，特别是有效的信道访问和路由方案的联合设计与提出的编码方案。

Networked wireless communications over multiple hops is rapidly emerging as the main architecture of future wireles systems, including multihop extensions of cellular and WiFi networks, mesh networks, and sensor networks. Common among these types of networks is that they are not completely unstructured (or ad hoc) networks, but traffic is routed and accumulated towards a common destination. Due to this characteristic property, these networks will be referred to as Networks with Traffic Accumulation, or NETAs. Traffic accumulation creates hot sposts or bottlenecks around the common destination because of the increased traffic load and interference. Despite the severity of the hot spot problem, there is a lack of efficient methods to cope with it. This research addresses the hot spot issue in NETAs by developing new distributed error correction strategies tailored to two important subclasses- line networks and tree networks. In line networks, the investigators study fundamental properties and the design of distributed channel coding protocals using serially concatenated and protograph-based constructions to strengthen the error correction capability near the destination without sacrificing badwidth efficiency. In tree networks, several source nodes may wish to employ a common relay node to broadcast their information to multiple destination nodes which may have access to side information from "overheard" source messages. The investigators explore a novel approach where each source uses a distinctlow rate code for transmission to the relay, whereas the decoded messages are re-encoded using a high rate "nested code". In addition, interlayer issues are considered, in particular the joint design of efficient channel access and routing schemes together with the porposed coding schemes.