CIS Colloquium, Apr 03, 2009, 03:00PM - 04:00PM, Wachman 447

CIS Colloquium, Apr 03, 2009, 03:00PM - 04:00PM, Wachman 447


Efficient Quality-of-Service Provisioning and Communications in Hybrid Wireless Networks


Xiaojiang (James) Du, North Dakota State University

Wireless networking and communication technology has been widely used in many areas, and is expected to grow rapidly in the next few years. At the same time, increasing proliferation of personal wireless gadgets (such as laptops, PDAs, and smart phones) continuously opens up new services and possibilities for users. In the past several years, much research has been done on various wireless networks, such as mobile ad hoc networks (MANETs), sensor networks, cellular networks, Wireless LANs (WLANs), WiMAX networks, vehicular ad hoc networks and cognitive radio networks. In our research, we considered a promising wireless network - Hybrid Wireless Networks (HWNs). An HWN consists of an infrastructure network (e.g., a cellular network) and a few ad hoc components (e.g., MANETs). By forming an HWN, one can achieve the benefits of both infrastructure wireless networks, such as good reliability and Quality-of-Service (QoS) support, and ad hoc networks, e.g., larger coverage, low deployment cost, and flexibility.

However, not much work has systematically studied network design and performance of HWNs. In our research, we adopted the OFDMA (orthogonal frequency division multiple access) based IEEE 802.16e mobile WiMAX networks as the infrastructure network, as WiMAX networks are rapidly gaining popularity for broadband wireless services. We investigated efficient QoS routing and OFDMA resource allocation in HWNs via a systematic, cross-layer approach. The objective is to satisfy individual user’s QoS requirements while optimizing the overall system performance (e.g., throughput).

Both QoS support in traditional wireless networks and OFDMA resource allocation in cellular networks have been well studied. However, in HWNs, QoS routing and OFDMA resource allocation are highly correlated and this problem remains largely unexplored. In our research, we proposed jointly modeling and solving the QoS routing and OFDMA resource allocation issue in HWNs. The joint problem is NP-complete. We designed efficient heuristic solutions for solving the problem. Our simulation results showed that the heuristic solutions achieved near-optimal performance.

Dr. James Du is currently an Assistant Professor in Computer Science at North Dakota State University. Dr. Du received his B.E. degree from Tsinghua University, Beijing, China in 1996, and his M.S. and Ph.D. degrees from University of Maryland, College Park in 2002 and 2003, respectively. His research interests are wireless networks, computer networks, security, and systems. Dr. Du’s research has been sponsored by the National Science Foundation, Army Research Office, and NASA.

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