Effects of Link Rate Assignment in IEEE 802.11 Mesh Networks
ABSTRACT The IEEE 802.11 standard supports a variety of modulation and coding schemes (MCSs). In 802.11-based wireless mesh networks (WMNs) it is hence possible to adapt the link rate to the channel conditions. In particular, smaller link rates may be accepted for an increased spatial reuse. In an earlier study, we showed that this effect is suitable for increasing the max-min fair share throughput in a WMN operating with a TDMA channel access scheme. In this work, we investigate if the use of smaller link rates is also suitable for increasing the throughput of a WMN using a contention-based channel access mechanism. For this purpose, we analytically derive a guideline for link rate assignment as protection against hidden nodes and compute the costs and benefits of this mechanism in terms of MAC layer efficiency. A simulation study shows however that in a medium sized WMN this strategy is less advantageous than assumed and allows to give advices for practical mesh network deployments.
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ABSTRACT: The paper is devoted to WMN modeling using mixed-integer programming (MIP) formulations that allow to precisely characterize the link data rate capacity and transmission scheduling within time slots. Such MIP models are formulated for several cases of the modulation and coding schemes (MCS) assignment. We present a general way of solving the MMF traffic objective for WMN and use it for the formulated capacity models. Thus the paper combines WMN radio link modeling with a non-standard way of dealing with uncertain traffic, a combination that has not been to our knowledge considered so far in terms of exact optimization models. This combination, involving integer programming, forms the main contribution of the paper. We discuss several ways of solving the considered MMF problems and present an extensive numerical study that illustrates the running time efficiency of the different solution approaches, and the in uence of the MCS selection options and the number of time slots on the traffic performance of a WMN.Ad Hoc Networks 01/2011; · 1.94 Impact Factor