Radiation Efficiency Aware High-Mobility Massive MIMO With Antenna Selection

Abstract

High-mobility wireless communications have received a lot of attentions in the past few years. In this paper, we consider angle-domain Doppler shifts compensation scheme to reduce the channel time variation for the high-mobility uplink from a high-speed terminal (HST) to a base station (BS). We propose to minimize Doppler spread by antenna weighting under the constraint of maintaining radiation efficiency. The sequential parametric convex approximation (SPCA) algorithm is exploited to solve the above non-convex problem. Moreover, in order to save the RF chains, we further exploit the idea of antenna selection for high-mobility wireless communications. Simulations verify the effectiveness of the proposed studies.

High-Mobility CoMP Massive MIMO Uplink Transmissions: Channel PSD Analysis and Doppler Spread Suppression

“…Note that the performance balance among the multiple BSs is the main concern of this work. This differs a lot from [12] which considered only one BS. The remainder of this paper is organized as follows.…”

“…For sparse high-mobility scenarios with a few dominating paths, the small-scale uniform circular antenna array (UCA) and uniform linear antenna array (ULA) are adopted to separate the multiple Doppler shifts and eliminate ICI via array beamforming [3]. More recently, researchers resort to the large-scale antenna array [4]- [12] to deal with the richly scattered high-mobility scenarios including tunnels or urban areas. On one hand, for downlink high-mobility transmission, the authors in [9] proposed angle-domain Doppler shifts separation scheme to avoid the complicated The associate editor coordinating the review of this manuscript and approving it for publication was Matti HäMäLäInen .…”

“…Besides, the exact power spectrum density (PSD) of uplink equivalent channel is derived in [11], and an antenna weighting technique is further proposed to reduce the channel time variation. However, the scheme in [11] suffers from severe loss of energy radiation efficiency (ERE) when channel has small angular spread [12]. Then, the authors in [12] proposed an ERE aware Doppler spread suppression scheme, and an antenna selection scheme is further developed to save the RF chains.…”

“…However, the scheme in [11] suffers from severe loss of energy radiation efficiency (ERE) when channel has small angular spread [12]. Then, the authors in [12] proposed an ERE aware Doppler spread suppression scheme, and an antenna selection scheme is further developed to save the RF chains.…”

“…• We derive the exact channel PSD as well as the Doppler spread for the CoMP uplink transmissions, which differs a lot from the conventional single-BS scenarios [11], [12].…”