First generation wireless systems, which primarily provide analog voice service, are widely in use worldwide. Second generation systems support digital voice/data traffic; some of these systems are already deployed or undergoing deployment. Third generation wireless networks will ultimately carry multimedia traffic that are characterized by combination of different informaion streams of diverse nature (e.g., voice, video, image, data). Some of the salient features of multimedia applications are high speed and changing bit rates (periodic and bursty arrivals), several virtual connections over the same access, synchronization of different information streams, and various service/deliveIy requirements (QoS).

It is clear that next generation wireless networks will be required to interface with much higher bandwidth fiber-based wired networks, possibly carrying B-ISDN/ATM type traffic, which poses interesting management and control issues like admission control, resource sharing and link contol. The objective is to provide *A. Roy is presently with Lucent Technologies India Ltd., Bangalore, India. “seamless wireless communication” to users, irrespective of channel impairments.

Multimedia applications have varying bandwidth requirements. A media access control (MAC) protocol capable of assigning :multiple slots, based on demand and QoS requirements, is thus a natural choice. It is also desired that the protocol supports statistical multiplexing to improve channel utilizalion exploiting bursty nature of the traffic. In this paper, we propose a link control protocol which is a combination of a suitable MAC protocol and a priority based link management and control functionality to support multimedia streams over wireless. A reservation type access protocol capable of assigning multiple slots upon request is employed at the MAC layer. On the top of the MAC layer, a burst level admission control and link management function, based on a two-level priority mechanism, is designed to identify and associate together different components of the multimedia application and suitably handle them as parts of an integaetd flow. On a “call-basis,” a static priority is specified by the user to each component of the multimedia application, which is used during link activation. A second level of priority (dynamic priority) is assigned by the system on a “spurt-b,asis” according to the traffic of all components of the application, and is used during bandwidth allocation and reservation queue management.

Download pdf Performance of a Link Control Protocol for Local Wireless Multimedia Communications