Queueing behavior of individual mobiles in TDMA-based cellular systems

We present a technique for analyzing the queueing behavior of the forward link in a wireless cellular communications system, wherein a collection of mobile users share the total capacity of the forward link using a version of time-division multiple access (TDMA), as in Qualcomm´s high data rate (HDR) system. We model the arrival process of each forward link user as a batched Markovian arrival process (BMAP), and we model the signal-to-interference-plus-noise ratio (SINR) of each customer by a Markov chain that depends upon the user´s location and velocity. The Markov chain for the SINR then determines the maximal service that can be rendered to a user during a service frame. We assume each user is allocated a certain fraction of the total available time (not necessarily equal), but that this service time is given such that the aggregate throughput of the system is maximized. We model the allocation of service to individual users as a linear programming problem, and we solve for the optimal allocations. We then modify the Markov chain governing the user´s SINR and service rate to reflect the level of service provided to the user as a function of SINR. We discuss computation of the queue length distribution of the individual users, and we provide a limited number of numerical examples. From this, we draw some conclusions about system characteristics and the QoS of individual users.