A race-free bandwidth reservation protocol for QoS routing in mobile ad hoc networks

Routing protocols are an essential part of the efficient design of mobile ad hoc networks (MANETs). Existing routing protocols such as DSR, AODV, and TORA are based on a best effort strategy (C.E. Perkins, 2001), However, in order for MANETs to be practical for more demanding real time applications such as multimedia, providing a certain needed level of quality of service becomes an essential component in the communication protocol design (S. Chakrabarti and A. Mishra, 2001), QoS routing protocols provide the capability of finding a path between two nodes which satisfies the application layer´s minimum bandwidth requirements. Previous papers addressed this issue for different communication environments such as TDMA (time division multiple access) (I. Gerasimov and R. Simon, 2002) and CDMA (Code Division Multiple Access)-over-TDMA (S. Chen and K. Nahrstedt, 1999). While most of these models are generally more practical and less expensive, they impose on the designer the constraint of the hidden terminal and exposed terminal problems. The paper by Liao and Tseng (2002) addressed these issues and provided a TDMA-based bandwidth reservation protocol for QoS routing in MANETs. However, this protocol does not account for the race condition which can become more significant with increased node mobility, network density and higher traffic loads. This race condition is also a limitation of other QoS routing protocols, This paper addresses this issue and provides a protocol which enables the network to cope with this and other related problems such as parallel reservation. We also provide increased optimizations which significantly enhance the throughput and efficiency of the QoS routing protocol.