Massive MIMO with Multi-Antenna Users under Jointly Correlated Ricean Fading

Abstract

We study the uplink performance of massive multiple-input multiple-output (MIMO) when users are equipped with multiple antennas. To this end, we consider a generalized channel model that accounts for line-of-sight propagation and spatially correlated multipath fading. Most importantly, we employ the Weichselberger correlation model, which has been shown to alleviate the deficiencies of the popular Kronecker model. The main contribution of this paper is a rigorous closed-form expression for the uplink spectral efficiency using maximum-ratio combining and minimum mean square error channel estimation. Our result is a non-trivial generalization of previous results on massive MIMO with spatially correlated channels, thereby enabling us to have suitable designs for future massive MIMO systems. Numerical simulations corroborate our analysis and provide useful insights on how different propagation conditions affect system performance.

Iteratively Weighted MMSE Uplink Precoding for Cell-Free Massive MIMO

“…So (n, i)-th element of E{X H YX} is tr Y • E x i x H n where x i and x n is the i-th and n-th column of X, respectively. APPENDIX B PROOF OF (14) The conditional MSE matrix for UE k can be written as (5). Based on [12], we prove that (7) can also minimize MSE k = tr (E k ).…”

“…We can form R mk and Rmk in the block structure as [14] with (n, i)-th submatrix being R ni mk = E{h mk,n h H mk,i } and Rni mk = E{ ĥmk,n ĥH mk,i }, respectively. 1…”

“…Proof: The proof of Theorem II.1 follows similar steps in [12], [14], [22] and is therefore omitted.…”

“…Rayleigh fading channels, neglecting the spatial correlation that exists in any practical channel [6], [7]. A practical channel model for the scenario with multi-antenna UEs is the jointly-correlated Weichselberger model [13], [14]. Unlike the classic Kronecker channel, which models the spatial correlation properties at the APside and UE-side separately and neglects the joint correlation feature for each AP-UE pair [15], the Weichselberger model not only considers the correlation features at both the APside and UE-side but models the joint correlation dependence between each AP-UE pair.…”

Classification and Comparison of Massive MIMO Propagation Channel Models

“…As pointed out in [129], Ω can influence channel capacity and can be used to determine whether spatial multiplexing or diversity to be employed. In [90], WM was employed for LoS propagation of multiantenna user massive MIMO channel under jointly correlated Ricean fading. The uplink SE was further derived with a rigorous closed-form expression.…”