Fairness-Based Resource Allocation with Minimum Rate Guarantee in a Multiuser OFDMA System
We propose a resource allocation scheme based on Proportional Fairness (PF) for minimum bit rate guarantee in a multiuser, frequency-selective frame-based OFDMA system. Instead of considering subcarrier-and-bit allocation, we consider a more realistic scheduling which is performed at the beginning of each frame, while allowing time-slots multiplexing among active users. Our scheme aims to guarantee different minimum bit rates to different users, while throughput fairness among users is maintained. We formulate the optimization problem based on a multichannel proportional fairness objective function. Minimum bit rate guarantee is taken as the constraint. The optimization problem is solved by using the Lagrange multiplier method. Then, we use our fast cross-layer approach integrated to our optimization solution to schedule packets from finitely backlogged queues. Simulations with user mobility are conducted. The results show that the proposed scheme can serve users with satisfied minimum bit rate requirement. Furthermore, the simulation results also confirm throughput fairness among users.