Algorithmic aspects of capacity in wireless networks

Abstract

This paper considers two inter-related questions: (i) Given a wireless ad-hoc network and a collection of source-destination pairs {(si, ti)}, what is the maximum throughput capacity of the network, i.e. the rate at which data from the sources can be transferred to their corresponding destinations in the network? (ii) Can network protocols be designed that jointly route the packets and schedule transmissions at rates close to the maximum throughput capacity? Much of the earlier work focused on random instances and proved analytical lower and upper bounds on the maximum throughput capacity. Here, in contrast, we consider arbitrary wireless networks. Further, we study the algorithmic aspects of the above questions: the goal is to design provably good algorithms for arbitrary instances. We develop analytical performance evaluation models and distributed algorithms for routing and scheduling which incorporate fairness, energy and dilation (path-length) requirements and provide a unified framework for utilizing the network close to its maximum throughput capacity.Motivated by certain popular wireless protocols used in * Basic and Applied Simulation Science (CCS-5) and Na- Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. practice, we also explore "shortest-path like" path selection strategies which maximize the network throughput. The theoretical results naturally suggest an interesting class of congestion aware link-metrics which can be directly plugged into several existing routing protocols such as AODV, DSR, etc. We complement the theoretical analysis with extensive simulations. The results indicate that routes obtained using our congestion aware link-metrics consistently yield higher throughput than hop-count based shortest path metrics.

A model for calculating channel share of 802.11 access points with overlapping wireless cells

“…[7,8,12,16,18]) all assume interference is pairwise and binary, so they similarly do not address the non-equilateral triangle and receiver-side interference problems.…”

Flow admission control for multi-channel multi-radio wireless networks

“…This paper will estimate the path bandwidth and delay based on the TDMA MAC layer. TDMA scheduling, which aims to eliminate collision and guarantee fairness, has been studied extensively in the literature [28][29][30][31][32]. Kodialam and Nandagopal [28] studied the effect of interference on the achievable rate region in multihop wireless networks.…”

“…In [30], they extended their work to the multi-radio multi-channel wireless mesh networks. Kumar et al [31] developed analytical performance evaluation models and distributed algorithms for routing and scheduling which incorporate fairness, energy and dilation (path-length) requirements and provide a unified framework for utilizing the network close to its maximum throughput capacity. Alicherry et al [33] mathematically formulated the joint channel assignment and routing problem in multi-radio mesh networks, and established necessary and sufficient conditions under which interference free link communication schedule can be obtained and designed an simple greedy algorithm to compute such a schedule.…”

“…The challenging question now is to find a path, given the current reservation status of all links, whose bandwidth (the minimum among all links) is at least the required value, and whose delay is minimized among all potential paths. Unfortunately, this question is NP-hard for wireless networks with interference constraints since even computing a path with the maximum capacity is already NP-hard [28][29][30][31][32].…”

Optimization of the capacity of wireless mesh networks

“…The WMN integration with Internet is provided through special routers called mesh gateways. The problem of providing full optimization frameworks for WMNs has received significant attention lately (Kumar et al 2005;Karnik et al 2008). A very important requirement for the network performance evaluation is to maximize its capacity, defined as the fair throughput offered to each flow.…”