Performance of Heterogeneous Multiuser MIMO System with Cross-layer Design over Spatially Correlated Rayleigh Channel

By combing adaptive modulation (AM) and automatic repeat request (ARQ) protocol as well as user scheduling, cross-layer design (CLD) scheme for heterogeneous multiuser MIMO (MU-MIMO) system is presented in this paper, which takes the spatial correlation and heterogeneous users with independent non-identically distributed SNRs in practice into account. The performance of CLD scheme is investigated over spatially correlated Rayleigh channel. Based on the performance analysis and mathematical operation, using the normalized-SNR based scheduling scheme, the average spectral efficiency (SE) and packet error rate (PER) of MU-MIMO system are derived, and resulting accurate closed-form expressions are obtained. In order to simplify the performance analysis from accurate expressions, the simplified average SE and PER are further derived for weak correlation, which have simpler form than the accurate ones. Simulation results show that the derived accurate SE and PERs are in good agreement with the corresponding simulations, and the simplified expressions have the values close to the accurate ones, especially for weak correlation. Thus, the CLD performance of MU-MIMO in spatially correlated channel can be evaluated effectively.