Exclusion and Guard Zones in DS-CDMA Ad Hoc Networks
Exclusion and Guard Zones in DS-CDMA Ad Hoc Networks
复制标题
DS-CDMA Ad Hoc 网络中的排除区和保护区
DOI：
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发表时间：
2013
影响因子：
8.3
通讯作者：
M. Valenti
中科院分区：
文献类型：
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作者：
D. Torrieri;M. Valenti
在直接序列码分多址（DS-CDMA）ad hoc网络中的中心问题是防止远近问题。本文考虑了两种类型的保护区，可用于控制远近问题：一个基本的禁区和一个额外的CSMA保护区，可以建立的载波侦听多路访问（CSMA）协议。在禁止区中，没有移动设备物理存在，模拟了实际网络中始终存在的移动设备之间的最小物理间隔。潜在的干扰移动站超出发射移动的的禁止区域，但在其CSMA保护区域内，由协议去激活。本文提供了一个DS-CSMA网络的一种或两种类型的保护区的分析。建立了一个有限规模的网络模型，该网络中移动节点数量有限，空间分布均匀。该分析适用于一个封闭形式的表达式中断概率在Nakagami衰落的存在下，条件网络的几何形状。DS-CDMA和非扩频网络的禁区和CSMA保护区之间的权衡进行了探讨。扩展因子和保护区半径在实现指定级别的平均中断概率和传输容量方面提供了设计灵活性。与CSMA保护区相比，禁止区的优点在于，由于网络没有变薄，因此活动移动台的数量保持恒定，并且可以实现更高的传输容量。
The central issue in direct-sequence code-division multiple-access (DS-CDMA) ad hoc networks is the prevention of a near-far problem. This paper considers two types of guard zones that may be used to control the near-far problem: a fundamental exclusion zone and an additional CSMA guard zone that may be established by the carrier-sense multiple-access (CSMA) protocol. In the exclusion zone, no mobiles are physically present, modeling the minimum physical separation among mobiles that is always present in actual networks. Potentially interfering mobiles beyond a transmitting mobile's exclusion zone, but within its CSMA guard zone, are deactivated by the protocol. This paper provides an analysis of DS-CSMA networks with either or both types of guard zones. A network of finite extent with a finite number of mobiles and uniform clustering as the spatial distribution is modeled. The analysis applies a closed-form expression for the outage probability in the presence of Nakagami fading, conditioned on the network geometry. The tradeoffs between exclusion zones and CSMA guard zones are explored for DS-CDMA and unspread networks. The spreading factor and the guard-zone radius provide design flexibility in achieving specified levels of average outage probability and transmission capacity. The advantage of an exclusion zone over a CSMA guard zone is that since the network is not thinned, the number of active mobiles remains constant, and higher transmission capacities can be achieved.