Research Areas and Interests

Current research activities focus on distributed resource allocation, mobility management, quality-of-service provisioning, medium access control, scheduling, call admission control, congestion control, routing, cross-layer design and optimization, heterogeneous wireless and wireline interworking, information and communication systems for smart grid.

Vehicular Communication Networks: We have been developing networking protocols and algorithms for quality-of-service support. For example, we have proposed VeMAC, a novel multichannel TDMA MAC protocol proposed specifically for a VANET scenario. The VeMAC supports efficient one-hop and multi-hop broadcast services on the control channel by using implicit acknowledgments and eliminating the hidden terminal problem. The protocol reduces transmission collisions due to node mobility on the control channel by assigning disjoint sets of time slots to vehicles moving in opposite directions and to road side units. Analysis and simulation results in highway and city scenarios are presented to evaluate the performance of VeMAC and compare it with ADHOC MAC, an existing TDMA MAC protocol for VANETs. It is shown that, due to its ability to decrease the rate of transmission collisions, the VeMAC protocol can provide significantly higher throughput on the control channel than ADHOC MAC. [Please watch simulated vehicle traffic flows on YouTube http://youtu.be/GjYWe7eLJ3s and http://youtu.be/48daRU6ZpjI]

Cooperative Wireless Networking: We have been investigating radio resource allocation in a heterogeneous wireless access medium, and have developed a novel algorithm for the resource allocation. Unlike existing solutions in literature, the proposed algorithm is distributed in nature, such that each network base station/access point can perform its own resource allocation to support the MTs according to their service classes. The coordination among different available wireless access networks’ base stations is established via the MT multiple radio interfaces in order to provide the required bandwidth to each MT. A priority mechanism is employed, so that each network gives a higher priority on its resources to its own subscribers as compared to other users. [More details here]

QoS Support in Cognitive Radio Networks: We have been carrying out capacity analysis for voice traffic and data traffic in order to provide service quality satisfaction to the secondary users. We analyze the constant-rate voice capacity of a fully-connected network with slot-ALOHA and round-robin channel access, and propose two call admission control (CAC) algorithms for a non-fullyconnected network with slot-ALOHA channel access. The capacity analysis results of the slot-ALOHA scheme is used to develop a CAC procedure when all the voice flows have an identical statistical delay requirement. Further, two CAC algorithms (A1 and A2) are developed for a network with voice traffic flows having different delay requirements in which one (A1) is based on the theory of effective capacity and is considered as a benchmark to compare with the other.

Smart Grid: The smart grid is an electrical grid that uses information and communication technologies to gather information and act accordingly in an automated fashion to improve the efficiency, reliability, economics, and sustainability of electricity production, transmission, distribution, and consumption. A key enabler of the smart grid is the two-way communications throughout the power system, based on which an advanced information system can make optimal decisions on power system operation. Due to the expected deep penetration of renewable energy sources, energy storage devices, demand side management (DSM) tools, and electric vehicles (EVs) in the future smart grid, there exist significant technical challenges on system planning and operation. We have been working on EV integration, microgrid planning and operation.