认知Ad Hoc网络吞吐量分析与优化

考虑两个无线Ad Hoc网络（主网络与次级网络）的并存模型:主网络与次级网络节点依照不同密度的空间泊松点过程并存于同一区域并共享同一频谱，两种网络节点均采用时隙ALOHA协议，按照各自的传输概率进行通信。本文首先根据随机几何理论对来自本网络的自干扰与来自其它网络的互干扰进行建模，然后分别推导了在AWGN信道和Rayleigh衰落信道下，单网络及并存式网络时节点平均吞吐量的闭合表达式，最后采用优化准则得到最佳传输概率，使节点平均吞吐量达到目标性能上的最优。仿真结果表明:经推导的闭合表达式与仿真值相近；在比例公平准则下，传输控制策略能达到主网络与次级网络之间公平性与高效性的折中。 

Throughput Analysis and Optimization in Cognitive Ad Hoc Networks

We consider coexistence of two overlapping Ad Hoc networks: the primary network and secondary network. Nodes in each network are random and independently distributed according spatial Poisson point process with different densities, and different transmission probabilities are assumed for the nodes in each network according slotted-ALOHA protocol. When the two networks coexist, throughput in each network is limited by the self interference as well as the interference from the other network. In this paper, the interference for each network node is modeled as a simple Gaussian random variable which is equal to the sum of the interference not only from its own network but also from the other network, and based on stochastic geometry theory, closed-form expression of per-node throughput capacity is derived for single Ad Hoc network and overlapping Ad Hoc networks under AWGN channel and Rayleigh faded channel respectively. Optimization criteria are used to find the optimal transmission probability in each network to satisfy the expected performance. Simulation verified the theory analyses and results show that there is a tradeoff between high utilization and fairness when proportional fairness criterion is used.