Fair rate sharing models in a CDMA link with multiple classes of elastic traffic

In this paper we describe a modeling approach for studying fair rate sharing in a CDMA link. Capacity models derived for CDMA indicate that fair rate sharing belongs to the class of generalized processor sharing (GPS) schemes, as these were defined and studied by J.W. Cohen. From this starting point, we examine the steady-state characteristics of flows in a CDMA link considering multiple classes of non-real-time, or elastic, traffic. These permit us to evaluate the expected transfer times of flows and their blocking probabilities, in loss systems. We study traffic models with Poisson arrivals as well as arrivals from a finite-source population, in an Engset-like manner. Along the way we unveil some interesting properties of the GPS model –partially hidden in Cohen’s work– and extend some of its results. In addition, we revisit insensitivity and truncation properties of the stationary distributions encountered in GPS models, and extend to different access control policies.