On The Capacity Of Wireless Networks With Physical-Layer Network Coding And Infrastructure Support

In recent years, wireless networks have been a subject of intense interests, includ-ing wireless ad hoc network and machine-to-machine communications. It is a funda-mental work to analyze network capacity of wireless networks, which guides networkdesign, routing algorithm and scheduling. Asymptotic analysis is an efective way toinvestigate network performance. The milestone work concluded that per-node capac-ity decreases to zero when the network goes large, which indicates large scale wirelessad hoc network is unscalable. To achieve better network service, it is of great impor-tance in developing techniques to improve performance of large scale network.This paper studies capacity improvement of large scale wireless networks withinfrastructure support, physical-layer network coding and multihop transmission tech-niques. It frst introduces background of the research subject, and then classifes andsummarizes important existing results. Later it expounds basic knowledge of largescale wireless network asymptotic analysis, such as network topology, transmissionpattern, interference model and capacity defnition.In this paper, we study the multicast capacity of wireless ad hoc networks withinfrastructure support. The network under study is termed as hybrid wireless network,where L-Maximum-Hop resource allocation strategy is adopted to schedule ad hocmode and infrastructure mode transmission. We derive multicast capacity in ad hocmode and infrastructure mode, and then the aggregated capacity of the hybrid network.The relationship between the hybrid network capacity and the number of hops L isanalyzed. And we derive the optimal hop number L to achieve the maximal multicastcapacity. Then this paper discusses the condition to make the hybrid network scalable. We study the impact of physical-layer network coding (PNC) on the throughputof random wireless networks, including the one-dimensional and two-dimensional net-works. We consider three diferent transmission schemes, i.e., traditional fow-basedscheme, network coding scheme, and PNC scheme. We show that PNC scheme canimprove the throughput of wireless network by a constant factor without changing thescaling law compared to traditional fow-based scheme and network coding scheme.Furthermore, we demonstrate that PNC can undermine the efect of interference forthe one-dimensional network, and can achieve a tighter throughput bound for the two-dimensional network.For the large scale machine-to-machine (M2M) communication networks, thispaper studies the infuence of multihop transmission on network performance. we in-vestigate a M2M network with typical M2M features. Three key parameters, through-put capacity, delay and energy consumption, are analyzed to evaluate the performanceof the M2M network under multi-hop and single-hop manner. Our results state thatmulti-hop manner is efective to decrease the delay and energy consumption of M2Mnetwork, without beneft on the throughput. To satisfy the demand of the M2M net-work with diferent M2M features, we propose diferent optimal transmission rangerespectively to achieve best service.This paper studies three kind of techniques to improve performance of large scalewireless networks, and provides important insights into the understanding and designof network structure, routing and scheduling.