Access control, code allocation, and adaptive scheduling for UMTS TDD

In the UMTS-TDD (Universal Mobile Telecommunications System - time division duplex), the resource allocation and the quality of service are provided by the RRM (radio resource management). In this paper, methods to provide resources to real time (RT) application and non real time application in the downlink are proposed. The RT applications are usually carried on dedicated channel (DCH) but in certain conditions they are allowed to use DSCH (downlink shared channel) and NRT applications are carried only on the DSCH. Several algorithms are compared to specify which resources are allocated to a DCH. All the algorithms check that the power threshold is not reached in any slot. For the NRT applications, an adaptive scheduling developed by Lin is adapted to the system. The algorithm selected packets with respect to the channel state but by a credit system the scheduling is fair. Selected packets are carried by a DSCH. But a DSCH is allowed to be used only if its use does not disturb the transport of the RT applications. The CAC is not applied to the NRT applications.