A systematic study of Physical LAyer Network coding: from information-theoretic understanding to practical DSP algorithm design (P.L.A.N)

由于众所周知的无线电频谱的稀缺性，高频谱效率是无线网络的圣杯。直到最近，频谱效率的增长似乎已经走到了尽头，而网络编码的出现为无线网络的频谱效率前景带来了新的曙光。初步结果表明，使用网络编码可将频谱效率提高50%[2,3]。如此显著的性能增益对于宽带蜂窝系统、无线传感器网络、水下通信场景等许多重要的带宽消耗应用至关重要。目前，网络编码受到了无线通信界的广泛关注；然而，现有的许多工作都集中在网络编码在上层的应用上，其对物理层（PHY）设计影响的研究直到最近才开始。本文的目的是在物理层系统地研究网络编码，我们不仅将描述物理层网络编码的基本限制，而且还将设计实用的数字信号处理（DSP）算法来实现这些理论结果所承诺的性能增益。拟议项目的新颖性在于，该项目将是英国第一个将信息论研究和DSP算法设计用于PHY网络编码的努力。这将通过首先推导网络编码的容量区域来实现，该容量区域为我们提供了系统性能的上界。有了这样更好的理解，我们将开发有效的传输协议和DSP算法，以在实践中实现这种最佳性能。为了进一步提高网络编码传输的性能，最近为应对同信道干扰而开发的干扰对准技术将应用于网络编码传输。信息论结果，如中断和符号错误概率，将开发和基于试验台的实验评估，从而对我们开发的方案有更深刻的理解。

High spectral efficiency is the holy grail of wireless networks due to the well-known scarcity of radio spectrum. While up to recently there seemed to be no way out of the apparent end of the road in spectral efficiency growth, the emerging approach of Network Coding has cast new light in the spectral efficiency prospects of wireless networks [1]. Initial results have demonstrated that the use of network coding increases the spectral efficiency up to 50% [2, 3]. Such a significant performance gain is crucial for many important bandwidth-hungry applications such as broadband cellular systems, wireless sensor networks, underwater communication scenarios, etc. Currently network coding has received a lot of attention from the wireless communication community; however, many existing works focused on the application of network coding to upper layers and the study of its impact on the physical layer (PHY) design only began recently. The aim of this proposal is to systematically study network coding at the physical layer, where we will not only characterize the fundamental limits of physical layer network coding, but also design practical digital signal processing (DSP) algorithms to realize the performance gain promised by those theoretic results. The novelty of the proposed project lies on the fact that this project will be the first UK effort to bridge information-theoretic studies and DSP algorithm design for PHY network coding. This will be done by first deriving the capacity region of network coding, which provides us the upper bound of the system performance. With such a better understanding, we will develop efficient transmission protocols and DSP algorithms to realize such optimal performance in practice. Interference alignment, a technology recently developed to cope with co-channel interference, will be applied to network coding transmissions for further performance improvement. Information-theoretic results, such as outage and symbol error probabilities, will be developed and testbed-based experimental evaluation will be carried out, so a more insightful understanding for our developed schemes can be obtained.