Performance Analysis of Scheduling Schemes for Rate-Adaptive MIMO OSFBC-OFDM Systems

Abstract

Dynamic channel-aware user-selection and resource-allocation schemes are attractive for providing high system performance for multiple-input-multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. In this paper, we investigate the combination of different techniques, resulting in user scheduling schemes for multiuser MIMO-OFDM systems employing orthogonal space-frequency block coding (OSFBC) over multipath frequency-selective fading channels. Our contribution is a performance analysis framework that evaluates the advantages of employing user scheduling in MIMO-OFDM systems employing OSFBC in conjunction with adaptive modulation schemes. We derive analytical expressions for the average spectral efficiency (ASE), the average bit error rate (BER), the outage probability, and the average channel capacity for different scheduling and adaptive modulation schemes. Discrete-rate and continuous-rate adaptive modulation schemes are employed to increase the spectral efficiency of the system. We assume a signal-to-noise-ratio (SNR)-based user-selection scheme and the well-known proportional fair scheduling (PFS) scheme. Both full- and limited-feedback channel information scenarios are considered. Using the results obtained from both mathematical expressions and numerical simulations, we compare the presented schemes and show their significant advantages. Finally, the impact of spatial correlation on the performance of the system under study is analyzed and evaluated.