Performance of a link adaptive system in UMTS networks

In the UMTS network, the radio link is neither reliable and nor stationary. In order to provide the Quality Of Service (QoS) and to optimize the radio resource consumption, we propose to dynamically adapt the parameters of the Radio Access Network. We first simulate the behavior of the network. Those results let us predict if a set of parameters provides or not the required service. At every Transmission Time Interval, and with respect to the expected channel conditions, we will select among the sets of parameters that provide the service, the one that will optimize the efficiency. We provide tables that indicate the set of parameters to select with respect to the required QoS. We show that in favorable cases, adaptive coding could often increase the efficiency by 10%, or even 40 % in the most favorable case.