Adaptive Scheduling for Heterogeneous Traffic Flows in Cellular Wireless Ofdm - Fdma Systems ∗

In this paper we study the performance gain achieved by introducing dynamic subcarrier scheduling schemes to OFDM systems in the presence of heterogeneous traffic streams. Dynamic subcarrier scheduling copes with channel state variation by dynamically assigning different subcarriers to terminals, e.g. in the downlink of a cellular system. In addition to the channel state variations, also the arrival of data is highly variable for most applications. This calls for schemes that exploit both sources of variation. In the homogeneous traffic scenario, dynamic subcarrier scheduling in combination with semantic queueing mechanisms can significantly increase the capacity of an OFDM cell. In a heterogeneous traffic scenario, however, these mechanisms do not simply carry over. Therefore, in this work we study first the performance increase achieved for heterogeneous flows by purely switching from static to dynamic subcarrier scheduling and then introduce a semantic traffic management scheme that improves the achieved performance further by sacrificing the transmission of semantically unimportant video packets for important video packets and for packets related to HTTP.