Optimal admission control in high speed downlink packet access network

Abstract

High Speed Downlink Packet Access (HSDPA) defines a new High Speed Shared Channel (HS-DSCH) which allows for practical speeds up to 10 Mbps. Among all the changes introduced by HSDPA, the most prominent ones regarding QoS are the inclusion of link adaptation, Hybrid ARQ and the quick Scheduling algorithms. In HSDPA the Radio Network Controller (RNC) is still the responsible for admitting new users but also for handling different kinds of traffics of different users over the same channel. One of the mostly adopted solutions for admitting new users assuring QoS comprises an admission control based on performance. The main focus of the work presented in this paper is to propose two admission control algorithms that take into account that this guard power varies according to the channel conditions of each user, the number of allowed users. We consider a queue (modeling HSDPA channel) with multimedia input, Real-Time jobs (RT) and Non-Real-Time jobs (NRT), which can be controlled by accepting or rejecting arriving jobs. Our goal is to minimize the discounted cost over finite or infinite horizon and to find two thresholds that depend on the charge of the channel for managing the access of different services packages, while giving access priority to packets RT.