The Effects of Time and Frequency Domain Resource Partitioning in OFDMA Systems

A general problem in multi-cellular radio systems is the allocation of radio resource subsets to base stations. In OFDMA systems, the partitioning scheme, either time or frequency partitioning, directly affects the possibility to exploit diversity in scheduling algorithms. This paper provides a description of the effects of different resource partitioning schemes concerning the OFDMA scheduling of downlink connections in a multi user scenario. Further, a detailed performance analysis of an exemplary scenario is given. It is shown that there is a superposition of two effects. The first is the dependency of the OFDMA scheduler on the frequency diversity, depending on the number of usable subchannels, and the second effect is the influence of the power allocation for the subchannels. When the total transmission power is fixed, the mean power per subchannel increases with a reduced number of used subchannels. Simulation results show that the domination of the first or second effect depends to a great extent on the traffic characteristics in the system.