An adaptive subchannel allocation algorithm for OFDM-based wireless home networks

We present a novel, adaptive subchannel allocation algorithm for the downlink channel of a multiuser, OFDM-based wireless home network. Since channel resources are not adaptively allocated in a traditional OFDM system, some of the users with fixed frequency channel allocation may experience deep fading in a frequency-selective multipath environment. This problem can be mitigated using an adaptive algorithm, which can be modeled as an optimization problem that allocates the proper number of subchannels to achieve maximum channel capacity. We employ the classical bipartite matching algorithm to achieve optimal OFDM subchannel allocation. Simulation results show that the total capacity increases remarkably, and that higher channel capacity is achieved when the number of users is increased. In a wireless environment, the reallocation overhead can be large. As such, we propose a hybrid method for subchannel allocation to support more users while reducing the reallocation overhead. We simulated the performance of the hybrid algorithm and compared it with the matching-only algorithm.