Study On Resource Reservation QoS Mechanisms In Mobile Networks

In recent years, with the rapid development of portable computers, PDA and wireless communication technologies, the cost of communication and computing devices have been reduced, and it makes common citizens be willing to accept mobile information services as daily necessity.However, with the fast increase of mobile users and mobile application fields, people pay more and more attention and requests to the Quality of Services (QoS), especially in mobile real-time applications such as distance information accessing, video conferencing and video-on-demand. This requires the mobile networks to satisfy some parameters such as bandwidth, delay, delay jitter and throughput, etc. Normal mobile networks have no special mechanism to ensure QoS. They only offer best-effort or unreliable services, so the problem will not be solved until the mobile networks have some means to guarantee QoS.In this paper, based on introduction of the basic conception of mobile computing, we firstly emphasize the general concepts, main problems, mechanisms and approaches of QoS specification and management in mobile computing, and then present a survey of recent developments in this field.In general, QoS management and control in mobile networks includes context awareness, management adaptivity, resource management and reservation. They impose significant effects on QoS in data transmission, etc. It is a challenge to provide good resource reservation for mobile hosts. The Resource Reservation Protocol (RSVP) can establish and maintain reservation for IP networks. However, RSVP is designed for fixed networks and hence inadequate for mobile environment. This paper proposed a protocol named RSVP-C, which aims at how to reserve resources for mobile cellular networks. This protocol can establish both active and passive resource reservation route. The message format and reservation mechanism of RSVP-C are also given, and the algorithm for creating new reservation routes, which can limit the max length of the routes, is proposed, This kind of hierarchical routing method can decrease the network overhead by extending existing resource reservation routes to create new ones.We established a discrete-event simulation model by using Markov chains to simulate the overhead, etc., and we compared the results with existing resource reservation protocols. The simulation results show that our protocol has a better performance than existing protocols in many cases.Finally, we summarize our main works and introduce our research works in the future.