QoS-aware and Cross-layer Wireless Network Protocols

Each type of media and application demands distinct QoS, in terms of bandwidth, loss, delay, jitter, user priority, etc. Therefore, QoS support for multi-rate multimedia services in wireless networks is vital. My research is focused on designing QoS-aware and cross-layer protocols in multi-hop ad hoc, sensor, cognitive, cellular and WiMAX networks. Besides, my research considers dynamic and soft QoS for multimedia applications, by exploiting the characteristics (e.g., loss tolerance and scalability) of multimedia bitstreams. I am also interested in QoS aware cross-layer MAC, routing and transport protocols in 4G heterogeneous wireless networks, in order to support multimedia, telemedicine, environmental and process monitoring applications.

Projects:

• Spectrum-aware Cross-Layer Protocols for Mobile Ad hoc Networks under Dynamic Spectrum Access:Today’s wireless networks often suffer from limited data rates as they are designed to operate on one or a few fixed narrow frequency bands. The dynamic spectrum assignment based wireless networks (DSAN) enable the users to operate in the best available frequency band(s) over a wide frequency range, thereby providing large bandwidth. However, the dynamic spectrum access can degrade the performance of existing network protocols, which are designed to operate in a fixed frequency band. This requires research in designing novel network protocols for DSANs. In this project, we are designing the cross-layer spectrum management, MAC and routing protocols for supporting multimedia applications over DSANs. 

• Multimedia QoS-aware Intelligent Component-based Routing Schemes for MANETs: The Mobile Ad hoc Network (MANET) is a popular type of wireless network with many applications, such as in sensor networks, emergency communications in disaster-hit areas, vehicular communication, military and airborne networks.The transmission of multimedia data in MANETs requires availability of stable and good quality routes to support the QoS requirements, such as large data rates, low packet losses, bounded delays, longer route life time, etc. However, the use of multiple hops and presence of mobile nodes in MANETs make it difficult to find such routes. In this project, we propose to carry out research in developing robust and QoS-aware cross-layer routing protocols for MANETs to support multimedia applications (such as video-on-demand, video chat, wireless Internet browsing, teleconferencing).

• QoS Issues in Ad Hoc Networks:The advances in wireless communications and growth of real-time applications have necessitated the development of wireless networks that support a high quality of service (QoS). A number of MAC protocols have been proposed in recent years, each of which has focused on improving and optimizing a few selected QoS issues. We introduce a new QoS-aware MAC protocol for ad hoc networks that concurrently addresses several QoS issues. Ours is an asynchronous scheme that can handle multi-rate and multi-hop real-time traffics, reduce hidden terminal problems, provide different QoS requirements for different real time traffics, and has bounded end-to-end delay for real time traffics in multi-hop environment. Two additional new features, to enable bandwidth preservation and admission control are also being looked into. The goal is to outperform IEEE 802.11 in terms of the QoS and be able to efficiently handle a wide range of load conditions. We are also investigating the corss-layer design of MAC lay fragmentation while considering the compressed H.264 video and PHY characteristics.

• High Speed Video Streaming over Mobile WiMAX