Dynamic linear precoding for the exploitation of known interference in MIMO broadcast systems

Abstract

This paper introduces a novel channel inversion (CI) precoding scheme for the downlink of phase shift keying (PSK)-based multiple input multiple output (MIMO) systems. In contrast to common practice where knowledge of the interference is used to eliminate it, the main idea proposed here is to use this knowledge to glean benefit from the interference. It will be shown that the system performance can be enhanced by exploiting some of the existent inter-channel interference (ICI). This is achieved by applying partial channel inversion such that the constructive part of ICI is preserved and exploited while the destructive part is eliminated by means of CI precoding. By doing so, the effective signal to interference-plus-noise ratio (SINR) delivered to the mobile unit (MU) receivers is enhanced without the need to invest additional transmitted signal power at the MIMO base station (BS). It is shown that the trade-off to this benefit is a minor increase in the complexity of the BS processing. The presented theoretical analysis and simulations demonstrate that due to the SINR enhancement, significant performance and throughput gains are offered by the proposed MIMO precoding technique compared to its conventional counterparts.

Exploiting Constructive Interference for Simultaneous Wireless Information and Power Transfer in Multiuser Downlink Systems

“…The relevant works focus on exploiting the constructive superposition of useful and interfering signals, to utilise interfering signals as first explored for closed-form precoders [22]- [25]. In [26] a symbol-level precoding is introduced where the conventional optimization constraints are adapted to accommodate constructive interference for phase shift keying modulation (PSK).…”

Large load-controlled multiple-active multiple-passive antenna arrays: Transmit beamforming and multi-user precoding

“…T is calculated on a symbol-by-symbol basis as follows [4]: First, R is calculated according to Eq. (14).…”

“…In [4] is described a symbol-level zero forcing beamforming (ZFBF) method. This technique leaves unaffected the symbollevel interference that leads to an increase of the receive signal-to-noise-ratio (SNR) and cancels only the destructive interference.…”

“…This approach is very useful in cases where a system operates in the low SNR regime, given that typically the transmission power is constrained to an upper bound. Numerical simulation results have shown that this constructive interference ZFBF (CI-ZFBF) scheme outperforms its userlevel counterpart [4].…”

Spatial peak power minimization for relaxed phase M-PSK MIMO directional modulation transmitter

“…Other than time and frequency resources [2], [3], precoding at the transmitter [4], [5] in order to use the spatial dimension has shown a significant potential to improve the data rate by reducing the interference and satisfying the quality of service at the users. As another paradigm to combat the interference, directional modulation [6]- [9] and constructive interference [10]- [12] have been developed to communicate multiple interference-limited or interference-free streams with the receiver. In directional modulation, the antenna weights are designed such that the phase and signal-to-noise ratio (SNR) of the receiving signal on each antenna of the receiver are respectively equivalent to the phase and SNR of a specific desired symbol.…”