Rutgers University
Department of Electrical and Computer Engineering
Ph.D. Thesis Abstract

Quality-of-Service based bandwidth allocation in integrated multiservices wireless networks


Parthasarathy Narasimhan

    Third generation wireless information networks will be required to support integrated multimedia services, with high penetration and high throughput. The demand for these services is expected to increase greatly. With high user densities, effective usage of the bandwidth at the medium access layer (MAC) is necessary to realize the expected throughput, while maintaining quality-of-service (QoS) requirements of user applications.

    In this dissertation, we study bandwidth allocation policies at the MAC layer of integrated, multiservices wireless networks. In particular, we study two time-slotted systems - Packet Reservation Multiple Access (PRMA) and Wireless ATM - and propose bandwidth allocation policies that meet the QoS requirements of user applications.

    We propose a variant of PRMA, called Frame Reservation Multiple Access (FRMA), to reduce receiver activity, extend battery life, and to accommodate time-division duplex (TDD) of uplink and downlink transmissions. We present an exact analysis of an FRMA system by modeling it as a Markov Chain. We formulate an optimization problem to choose the design parameters with a view to optimizing system performance.

    We extend the voice-only FRMA protocol to integrate voice and data sources in the same system using a dynamic movable boundary scheme. Bandwidth for the data subsystem is allocated without affecting the capacity of the system to support voice sources. To choose design parameters to maximize expected bandwidth available for the data subsystem, we formulate an optimization problem and obtain heuristic solutions. Even though the solutions to the above problem are approximate, the computed performance measures by implementing these solutions are accurate.

    A description of a wireless ATM network followed by a discussion of the issues relevant to the design of the Medium Access Control layer and the Data Link Control (DLC) layer follows. The base station in the wireless ATM network has complete con- trol over bandwidth allocation to the many users in the cell. We propose a solution to the problem of bandwidth allocation for variable bit{rate (VBR) sources in this system with centralized bandwidth allocation. We propose two criteria that could be used to distribute the inevitable packet loss amongst the users in such a way that each user gets an even share of the bandwidth. We conjecture that using either of the two criteria mentioned above to allocate bandwidth for VBR sources leads to the convergence QoS experienced by each source in the system to a constant value. Assuming these conjectures were true, we derive a simple expression that would determine the feasibility of the QoS requirements of the sources given the bandwidth that is available. This expression could be used for connection admission control (CAC) purposes.

Ph.D. Dissertation Director: Professor Roy D. Yates

May, 1996

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