Downlink Resource Management for Packet Transmission in MIMO-OFDM Wireless Communication Systems

In this paper, a downlink RRM (radio resource management) scheme is proposed for packet transmission in MIMO-OFDM (multiple input multiple output-orthogonal frequency-division multiplexing) wireless communication systems. Within this scheme, the useful OFDM subcarriers in each TTI (transmission time interval) are divided into two groups: LRG (localized resource group) and DRG (distributed resource group). LRG is TF (time-frequency) continuous, and it is scheduled to low-speed users based on the slowly varying channel states to obtain better multi-user diversity. While DRG is composed of discrete TF hopping patterns, and it is allocated to high-speed users, in order to fully utilize time-frequency diversity against the rapid varying channels. Multi-antennas are adopted in spatial multiplexing mode. A two-step proportional fair scheduling is also proposed to work with the scheme. Simulation results show that the proposed scheme can achieve a higher system throughput than the scheme adopting chunk based scheduling only, and it can also guarantee fairness among users