Power Efficient MIMO Techniques for 3GPP LTE and Beyond

Abstract

Environmental issues and the need to reduce energy consumption for lowering operating costs have pushed power efficiency to become one of the major issues of current research in the field of wireless networks. The objective of the Green Radio research programme (Core 5) of Mobile VCE is to deliver reduced power consumption of radio access networks. This paper attempts to show that an efficient exploitation of multiple antenna techniques and multiuser diversity in both the time, frequency as well as the space domain can significantly ease the power requirements of a base station, whilst maintaining the same levels of service. Different MIMO transmission and precoding schemes proposed for LTE, achieving varying degrees of multiuser diversity are examined.

Green radio: radio techniques to enable energy-efficient wireless networks

“…A link adaptation approach is also taken into consideration to ensure the most energy saving transmission mode is employed within the allocated resource for a required QoS level. As an example from [7], Fig. 3b shows the ECG performance of different MIMO precoding schemes compared to using the single-user MIMO diversity scheme space frequency block coding (SFBC) as the baseline case.…”

Power Efficient Dynamic Resource Scheduling Algorithms for LTE

“…Unitary codebook based beamforming has shown capabilities in achieving spatial multiuser diversity gain and spatial multiplexing (SM) gain [5]. Depending on the spatial resource allocation process, unitary codebook based beamforming defines two modes of operation.…”

“…Both the base station (BS) and the mobile terminal (MT) are aware of the predefined set of unitary precoding matrices, and MTs feed back only the index of a preferred pre-coding matrix and the corresponding effective signal-to-noise ratio (ESINR) of the preferred matrix. Previous work [5] has shown the capabilities of this precoding scheme in achieving spatial multi-user diversity gain and spatial multiplexing (SM) gain.…”

Unitary beamforming techniques enhancing VoIP call admittance capacity

“…Unitary codebook based beamforming is capable of achieving spatial multiuser diversity gain and spatial multiplexing gain [8]. Unitary codebook based beamforming suggests that a predefined set of antenna beams is used which ensure a uniform sector coverage.…”

“…A zero-norm fading indicator metric is adopted according to eq. (8). As an indication of resource allocation on fading instances, the ratio of the frequency channel responses with gains lower than the average received response is adopted.…”