The impact of mobility on call admission control and scheduling in wireless networks
by Meng Zhang
Ph.D. Electrical and Electronic Engineering
xvi, 111 leaves : ill. ; 30 cm
User mobility is the principal driving force for wireless communication systems. How to handle user mobility efficiently is a very important issue in radio resource management. The aim of the thesis is to study the impact of mobility on call admission control and packet scheduling in different wireless cellular networks....[ Read more ]
User mobility is the principal driving force for wireless communication systems. How to handle user mobility efficiently is a very important issue in radio resource management. The aim of the thesis is to study the impact of mobility on call admission control and packet scheduling in different wireless cellular networks.
An analytical model is developed to evaluate the mobility/capacity conversion process in TDMA/FDMA wireless networks with different resource allocation strategies. Given a QoS requirement, a wireless network has to sacrifice some of its capacity to support an increase in mobility. The model can guide us in designing a more efficient mobility handling strategy. The study also has a more practical implication on network architecture: a wireless network, if designed correctly, should have a free convertibility between mobility and capacity. When user mobility decreases, a network should be able to take advantage of the mobility change and convert it into a capacity gain and support more users
An analytical interference/call admission model is also developed to study the impact of the mobility on CDMA networks. The interference model includes the effects of soft handoff, power control error and shadowing. We combined this interference model with a Markov model to study the performance of CDMA systems with call admission control under various mobility and traffic conditions. An interference-cushion scheme is also presented to mitigate the negative effect of mobility on network capacity.
Finally, the impact of mobility on packet-data scheduling is investigated. We formulate the cross-layer scheduler design problem in a multi-user multiple-input-single-output (MISO) system under several different mobility-related scenarios and evaluate how throughput and fairness criteria change as user mobility varies. The model captures both the physical layer and system-level parameters affected by mobility. It provides new insights into how the schedulers should be designed according to mobility conditions.