Sumankumar Panchal’s research while affiliated with Indian Institute of Science Bangalore and other places

In this paper, we present a generic controller that ensures fair and efficient operation of IEEE 802.11 infrastructure wireless local area networks (WLANs) with multiple co-channel access points. Our controller addresses performance issues of long-lived TCP transfers in multi-AP WLANs, by overlaying a coarse time-slicing scheduler on top of a cascaded fair queuing scheduler. The time slices and queue weights, used in our controller, are obtained from the solution of a constrained utility optimization formulation. A study of the impact of coarse time-slicing on TCP is also presented in this paper. We also present a methodology to improve the performance of co-existing short-lived and interactive TCP flows. Finally, we report the results of experiments performed on a real testbed, demonstrating the efficacy of our controller.

In this paper, we present a generic plug-and-play controller that ensures fair and efficient operation of IEEE~802.11 infrastructure wireless local area networks with multiple co-channel access points, without any change to hardware/firmware of the network devices. Our controller addresses performance issues of TCP transfers in multi-AP WLANs, by overlaying a coarse time-slicing scheduler on top of a cascaded fair queuing scheduler. The time slices and queue weights, used in our controller, are obtained from the solution of a constrained utility optimization formulation. A study of the impact of coarse time-slicing on TCP is also presented in this paper. We present an improved algorithm for adaptation of the service rate of the fair queuing scheduler and provide experimental results to illustrate its efficacy. We also present the changes that need to be incorporated to the proposed approach, to handle short-lived and interactive TCP flows. Finally, we report the results of experiments performed on a real testbed, demonstrating the efficacy of our controller.

Hand-held devices consume significant amount of energy while downloading large files or while streaming multimedia over a WLAN. IEEE 802.11 for WLANs provides PSM mechanism to reduce the energy consumption of a wireless device by allowing the wireless interface to go into sleep mode whenever possible. It is found that as stations (STAs) share the wireless channel at the packet level, wireless devices do not get enough opportunity to enter into the ‘doze’ state, making PSM ineffective. In this paper we present implementation and experimental evaluation of an energy saving scheme implemented over a home-grown centralised WLAN performance enhancing device, ADWISER, ([1], [2], [3]) assisted by a proxy server. Our implementation is based on the time slicing approach discussed in [4], [5].