On Non-Stationary Urban Macrocell Channels in a Cooperative Downlink Beamforming Scenario

Abstract

Abstract-A common simplification in the treatment of random linear channels is the assumption of stationarity of the channel in time. The wireless channel is, however, known to be inherently non-stationary. We detail a methodology for non-stationarity analysis from an algorithmic perspective. For the determination of local quasi-stationarity regions, we consider a multi-link downlink scenario where multiple base stations use transmit beamforming to concurrently transmit to a single mobile terminal per time slot. We obtain an algorithm-specific measure, i.e., the signal-to-interference-plus-noise ratio (SINR) degradation, with which we evaluate local quasi-stationarity regions. Furthermore, we relate and compare the SINR degradation to the correlation matrix distance (CMD). In an urban macrocell scenario relevant to 3GPP Long Term Evolution (LTE), we find that the resulting local quasi-stationarity distances show the same trends, but that the CMD overestimates the average distances for our system model.

Impact of polarization on the achievable rate of MIMO systems with linear receivers

“…Both approaches are challenging to realize in practice. It is thus more realistic to assume the TX to only have statistical CSI which changes on a much slower scale than instantaneous CSI [9]- [11]. Based on statistical CSI, a low-complexity precoding can be used such as a semi-unitary precoding with equal power allocation [12].…”