Nilesh Khude

On the design of device-to-device autonomous discovery

This paper proposes a synchronous device discovery solution for ad-hoc networks based on the observations that time synchronization, along with an FDM based channel resource allocation, can lead to gains in terms of energy consumption, discovery range, and the number of devices discovered. These attributes are important for the success of proximity-aware networking, where devices autonomously find peer-groups over human mobility scales. In this paper, we develop the PHY and MAC protocols to enable autonomous device discovery. Using both simulations and stochastic-geometry based analysis, we validate our design, and argue that there can be significant gains over a conventional Wi-Fi based solution.

Enhancing 802.11 carrier sense for high throughput and QoS in dense user settings

The distributed coordination function (DCF) for 802.11 medium access control (MAC) leads to poor spatial spectral reuse and results in low user throughput in dense user settings. In this paper, we consider simple modifications to the carrier sense mechanism that substantially improve the bits/sec/Hz/area, without increasing transceiver complexity. For 802.11g and 802.11ac, we augment the CTS with channel gain information and modify the virtual and physical carrier sense for the duration of NAV in the CTS. In addition, we consider a roughly synchronized network with alternate control and data transmission phases. During the control phase, a carrier sense multiple access with collision avoidance (CSMA-CA) MAC is used to exchange a few RTS-CTS messages in a local network neighborhood to determine the transmission scheme in the ensuing data phase. Our methods enable the application of signal to interference and noise (SINR) based scheduling algorithms to WiFi networks resulting in tremendous increase in throughput and QoS/fairness.