Rajiv Vijayakumar

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We consider the following queueing system which arises as a model of a wireless link shared by multiple users. There is a nite number N of input ows served by a server. The system operates in discrete time t = 0; 1; 2; : : : . Each input ow can be described as an irreducible countable Markov chain; waiting customers of each ow are placed in a queue. The(More)
The combination of multiple radio nodes in conjunction with a suitably structured multi-hop or mesh architecture has the potential to solve some of the key limitations of present day wireless access networks that are based on single-radio nodes. This paper addresses the channel assignment problem for multi-channel multi-interface (radio) wireless mesh(More)
We consider the following queuing system which arises as a model of a wireless link shared by multiple users+ There is a finite number N of input flows served by a server+ The system operates in discrete time t 5 0,1,2, + + + + Each input flow can be described as an irreducible countable Markov chain; waiting customers of each flow are placed in a queue+(More)
The combination of multiple radio nodes in conjunction with a suitably structured multi-hop or mesh architecture has the potential to solve some of the key limitations of present day wireless access networks that are based on single-radio nodes. This paper addresses the static channel assignment problem for multi-channel multi-radio static wireless mesh(More)
Many portable client devices such as PDAs, laptops and cell phones are already equipped with multiple wireless radios, as are infrastructure side elements like access points and base stations. In this article, we argue that the increasing availability of such multiple radio nodes, in conjunction with a suitably structured multi-hop or mesh architecture, has(More)
In this paper we present a queueing model for a 802.11 wireless LAN under non-saturated conditions. Our model builds on previous work, but additionally takes into account heterogeneous arrival rates. In particular, we consider the case when there are two packet arrival rates in the network, with one set of stations generating packets at the lower rate and(More)
Carrier sense multiple access (CSMA) protocols require stations that wish to transmit to first check the shared medium for ongoing transmissions. However, in wireless networks stations may not be able to sense transmissions from all other stations; hence those at different locations can experience different amounts of contention, resulting in unfairness and(More)
Multi-hop ad hoc networks suffer from the "hidden" and "exposed" node problems which diminish aggregate network throughput. While there are various approaches to mitigating these problems, in this work we focus exclusively on the role of physical carrier sensing (PCS). Specifically, tuning the PCS threshold leads to a trade-off between the hidden and(More)
Multi-hop ad-hoc networks suffer from the presence of hidden and exposed nodes that diminish aggregate network throughput. While there are various approaches to mitigating these problems, in this work we focus exclusively on the role of physical carrier sensing (PCS). Specifically, tuning the PCS threshold leads to a trade-off between the ‘exposed’ and(More)