On the Effect of Imperfect Channel Estimation upon the Capacity of Correlated MIMO Fading Channels

Abstract

This paper deals with the impact of channel estimation errors on the capacity of correlated fading MIMO channels. In literature the effect of channel uncertainty at the receiver is often investigated with the assumption that channel estimation errors are identically distributed and independent of both SNR and channel correlation values. In this paper we extend the analysis by considering correlation among the channel estimation errors as typically happen when the MIMO channel to be estimated is spatially correlated. We propose and study upper and lower bounds on the MIMO channel capacity giving emphasis to the impact of the resulting channel estimation error, through its covariance matrix. The role played by the effective SNR and spatial correlation is studied by detailing the results to MIMO systems employing linear MMSE channel estimators

Optimal pilot design and power control in correlated MISO links

“…It assumes the use of (suboptimal) Gaussian random codebooks, which justifies the assumption of Gaussian inputs, in the present article as well. Additionally, this bound turns out to be reasonably close to the exact mutual information I(x; y|ĥ) in many practical situations [11], [12], which legitimizes its use as a figure of merit. Note that the time losses due to channel estimation (training) are not taken into account, and their optimization is not within the scope of the present article.…”

“…In Section IV, we will determine the optimal transmit covariance Q (innermost maximization) for both problems (9)/(10) and (11). In the next two sections, we complete the task by determining the optimal pilot Gram P (outmost maximization), first as in (11) without power control (Section V), and then as in (9)/(10) with power control (Section VI).…”

“…In the next two sections, we complete the task by determining the optimal pilot Gram P (outmost maximization), first as in (11) without power control (Section V), and then as in (9)/(10) with power control (Section VI).…”

On a Mutual Information and a Capacity Bound Gap of Pilot-Aided MIMO Channels

“…However, such assumptions are unrealistic in most communication scenarios. These restrictions are partly lifted in [11]. We propose a unified notation by means of a bilinear matrix operator, and further extend [11] to arbitrary transmit covariances.…”

Adaptive MIMO Channel Estimation Utilizing Modern Channel Codes

“…However, in practical systems large gaps between theoretically calculated capacity and realized data rates can be observed. The negative impact of imperfect channel knowledge on detection performance is significant (Dall'Anese et al, 2009). Those errors are especially high in mobile scenarios.…”