Bandwidth and buffer dimensioning for guaranteed quality of service in wireless ATM networks

Extending ATM services to the wireless environment is intended to provide quality of service guarantees to multimedia applications. However, provisioning of QoS over the wireless link is made difficult by the fact that the burstiness of the channel and the re-transmission mechanism of the data link layer protocol result in a randomly varying transmission rate for the ATM connection. In this paper the randomly varying connection rate is modeled by a generalized Gilbert/Elliot (1959) channel model. A queueing analysis is performed for this system and the cell loss rate from the transmitter's buffer is evaluated in terms of the connection's allocated bandwidth, the buffer size and the parameters of the FEC code used in the ARQ system. Numerical results are presented for the cell loss rate as a function of the system parameters. These can be used for bandwidth allocation, buffer dimensioning and optimal code rate selection in order to guarantee the cell loss performance of the connection.