Teletraffic Performance Analysis of Multi-class OFDM-TDMA Systems with AMC

In traditional channelized multiple access systems, such as TDMA and FDMA, each user is assigned a fixed amount of bandwidth during the whole connection time, and the teletraffic performance in terms of time congestion, call congestion and traffic congestion can easily be obtained by using the classical Erlang-B formula. However, with the introduction of adaptive modulation and coding (AMC) scheme employed at the physical layer, the allocation of bandwidth to each user is no longer deterministic, but dynamically based on the wireless channel conditions. Thus a new connection attempt will be blocked with a certain probability depending on the state of the system and the bandwidth requirement of the connection attempt. In this paper, we present an integrated analytical model of multi-rate loss system with state-dependent blocking to evaluate the performance of multi-class OFDM-TDMA systems with AMC scheme.