Projects

Wireless mesh networks (WMNs) are a type of ad hoc wireless network that uses multi-hop wireless communications to provide or improve connectivity between wireless devices. The objective of this project is to maintain high network utilization while providing low queuing delays. This is a complex problem due to the time-varying capacity of the wireless channel as well as random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this comes at the cost of large queuing delays.

Delay Tolerant Networks (DTNs) are characterized as sparsely connected, highly partitioned, and intermittently connected networks. In such networks, the end-to-end path between a given pair may never exist. In this project, we developed a suit of solutions to problems of resource allocation, packet scheduling, and buffering in DTNs. Particularly, we developed and evaluated a novel routing protocol called self adaptive routing protocol (SARP). The protocol is characterized by employing an efficient updating strategy for the stochastic information at each node.

In this project, we considered the optimization of transmission power and delay in a wireless mesh networks. Our target is to dynamically determine a set of transmission rates for all the nodes in the network according to the nodes's data queue length and channel states, in order to initiate an optimal tradeoff between the power consumption and queuing time of transmitted data. We formulated this problem via a suite of modeling approaches, including the Jackson network model for data transmission and a Markov model for formulating the channel states transition.

The work on multimedia over wireless mesh networks has inspired us to explore other wireless transmission standards. For this reasons, we have chosen IEEE 802.16 (WiMax). In this work a test bed experiment is designed to demonstrate the framework on the Cross-Layer Superposition Coded Multicast for Robust IPTV Services over WiMAX. The Goal of this experiment is to transmit scalable video by Super Position Coding (SPC) to demonstrate different video quality will be received under different wireless channel quality.

The objective of this project is to develop a framework for facilitating green spectrum for cognitive radio protocols in wireless networks. The project aims at identifying the energy hungry components, spectrum activity, user mobility, user access patterns, spectrum sensing intervals, and spectrum interference levels. Also, proposing energy efficient secondary user scheduling in cognition, where user access decision is done based on interference measurements, user locations, and user eligibility.