Michael N. Krishnan

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—The 802.11 standard includes several modulation rates, each of which is optimal for a different channel condition. However, there are no simple and reliable methods for nodes to determine their current channel conditions. Existing link adaptation techniques use packet losses as an indication of poor channel conditions; however, when there is a significant(More)
—In a wireless local area network (LAN), packets can be lost due to a multitude of reasons. It is possible to reduce the probability of occurrence of some of these loss mechanisms by reducing packet length at the medium access control (MAC) layer. However, there is an inherent tradeoff in that shorter packets decrease efficiency with respect to overhead. In(More)
— As a Carrier Sense Multiple Access (CSMA) network , the performance of IEEE 802.11 networks highly depends on the accuracy of the carrier sensing procedure. However, conventional carrier sensing approaches suffer from the well known hidden and exposed node problems, adversely affecting aggregate throughput of the IEEE 802.11 networks. In this paper, we(More)
—Current 802.11 networks do not typically achieve the maximum potential throughput despite link adaptation and cross-layer optimization techniques designed to alleviate many causes of packet loss. A primary contributing factor is the difficulty in distinguishing between various causes of packet loss, including collisions caused by high network use,(More)
—Current 802.11 networks do not typically achieve the maximum potential throughput despite link adaptation and cross-layer optimization techniques designed to alleviate many causes of packet loss. A primary contributing factor is the difficulty in distinguishing between various causes of packet loss, including collisions caused by high network use,(More)
—Collision and fading are the two main sources of packet loss in wireless local area networks (WLANs) and as such, both are affected by the packetization at the medium access control (MAC) layer. While a larger packet is preferred to balance protocol header overhead, a shorter packet is less vulnerable to packet loss due to channel fading errors or(More)
—In this paper, we propose an end-to-end system which can be used to simultaneously generate (a) 3D models and associated 2D floor plans and (b) multiple sensor e.g. WiFi and imagery signature databases for the large scale indoor environments in a fast, automated, scalable way. We demonstrate ways of recovering the position of a user carrying a mobile(More)
—Access Point (AP) selection is an important problem in WLANs as it affects the throughput of the joining station (STA). Existing approaches to AP selection predominantly use received signal strength which does not take into account collisions and interference level at each STA. In this paper, we exploit the local channel occupancy of the joining STA as(More)
— The volume of multimedia traffic over wireless networks has been steadily increasing over the past decade. Unlike web browsing applications, multimedia data needs to satisfy stringent delay requirements since late packets are as good as lost packets. In this paper, we present a framework for the nodes in 802.11 networks to estimate the distribution of(More)
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