Performance analysis of session oriented data communications for mobile computing in cellular systems

Future cellular communication systems must seamlessly support services for a wide range of user needs, including voice, data, video and multi‐media. It is envisioned that mobile users may do much computer processing in an off‐line mode but must occasionally connect to a network in order to exchange data and/or files. For this purpose a communication session is initiated. During the session the user has access to network resources, although this access may be shared with others. Owing to the mobile environment, the user's connection to the network during a session may be severed. Since the mobile user can act semi‐autonomously, such disconnections can be transparent. That is, the mobile user can continue to function in an off‐line mode while the system will begin transparent automatic reconnection attempts to reestablish a link to the network. Only after a fixed (given) number of such attempts to reconnect have failed, is the session deemed to have failed. The issue is complicated by the hostile mobile radio environment and by user mobility. We consider session‐oriented communications and develop a tractable analytical model for traffic performance based on multi‐dimensional birth–death processes. The approach allows consideration of various platform types, such as pedestrians, automobiles, and buses, which may have very different mobility characteristics. Performance characteristics, such as: blocking, forced session termination, carried traffic, the average time per suspension, and the average number of suspensions per session, are calculated.