物理层网络编码在无线多址接入系统中的应用

This project aims to investigate a new frontier for physical-layer network coding (PNC): its role and utility in non-relay networks. PNC was originally proposed by the Co-I (Prof. Soung Chang Liew)’s research group in a Mobicom 2006 paper [1]. By exploiting network coding at the physical layer, PNC could boost throughput in wireless relay networks by 100% [1]. Most, if not all, prior studies of PNC focused on its use in relay networks. To increase throughput, PNC allows several sources in a wireless network to transmit simultaneously. The PNC receiver then derives a network-coded packet (e.g., bit-wise XOR of the source packets) from the overlapping signals. In the relay setting, the PNC receiver is a relay, and it just forwards the network-coded packet to other nodes. In the non-relay setting, however, the PNC receiver is the final destination: its ultimate target is not the network-coded packet, but the individual messages from the concurrent transmitters. An interesting question is whether the network-coded packets as derived by PNC decoding are still useful? ..In this proposal, we present a system architecture, named network-coded multiple access (NCMA), in which PNC decoding is combined with traditional multiuser decoding (MUD) to boost throughput in multiple-access wireless networks. Our quick prototype of NCMA on the software-defined radio platform has yielded evidence that the network-coded packets obtained by PNC decoding can be leveraged to increase system throughput, even in the non-relay setting. Encouraged by the preliminary findings, this proposal puts forth a full-scale three-year research plan. The plan includes two interrelated components: (1) Comprehensive system prototypes and experimentation. (2) Fundamental theoretical analyses to explain our experimental observations and to feed ideas for further enhancements to the system prototypes.

本项目为物理层网络编码（PNC）研究开辟一个新领域：PNC在非中继网络中的应用。在无线中继网络中，PNC允许多个源节点同时发送信息，从而将吞吐量提高100％ [1]。PNC接收机基于重叠信号计算出一个网络编码数据包。在中继系统中，PNC接收机将网络编码数据包转发至其他节点。而在非中继系统中，PNC接收机则是最终目的地：其目标是得到各个源节点同时发送的每个源信息。一个重要的问题是，PNC解码器得到的网络编码数据包在非中继网络中是否仍然有用？.本项目提出一个新的系统，网络编码多址接入（NCMA），将PNC解码器与多用户解码器（MUD）相结合，来提高网络的吞吐量。我们基于软件无线电平台快速开发的NCMA原型机证实，PNC解码器获得的网络编码数据包是有用的，并且可以提高系统的吞吐量。受到初期研究成果的鼓励，我们将开展基础理论研究以解释观察到的实验现象，并根据理论研究的结果拓展新的NCMA系统设计。

本项目为物理层网络编码（PNC）的研究开辟了一个新领域：PNC在非中继网络中的应用。我们提出了一个新的系统，网络编码多址接入（NCMA），将物理层网络编码（PNC）解码器与多用户解码器（MUD）相结合，来提高网络的吞吐量。我们通过基于软件无线电平台开发的NCMA原型机证实，PNC解码器获得的网络编码数据包是可用的，并且可以提高系统的吞吐量。..我们成功地解决了NCMA系统的一些关键和实际问题，特别是同步的难题。更重要的是，我们在软件定义无线电设备上成功地开发了一个支持TCP / IP网络协议的NCMA原型机系统。该方面的科研成果在许多国际顶级期刊和会议上发表（例如 SCI 1区期刊IEEE JSAC）。..综上所述，本项目的执行过程非常顺利。具体来说，我们不仅成功完成了最初制定的NCMA系统研究科研目标，而且还将研究内容进一步拓展到了移动UAV的NCMA系统上。我们在国际顶级期刊和会议（大多数是IEEE组织）发表了16篇学术论文。