Energy Efficient Massive MIMO Point-to-Point Communications with Physical Layer Security: BPSK vs QPSK Decomposition

Abstract

Massive multiple-input multiple-output systems (mMIMO) are the most prevalent candidates for the next generation of wireless communication. Yet even with mMIMO systems the joint optimization of spectral and energy efficiencies can be only attained by combining high order signal constellations and efficient power amplification. In order to push this limitation, the transmitter can spread the information into several amplification branches, which are the result of the decomposition of multilevel constellation symbols into quasi constant envelope signals. Nevertheless, the high number of antennas involved in this type of communication leads to an increase of the channel matrix's size and therefore the complexity of the equalization process can create drawbacks for the power consumption and latency. In this paper we will study the combination of a multi-layer transmitter with a low complexity receivers based on an iterative block decision feedback equalizer (IB-DFE). These receivers avoid the matrix inversion operation in the equalizer the feed-forward by replacing it with an equal gain combiner (EGC) or a maximum ratio combiner (MRC) module. Results show that can be used without penalties on performance provided that the number of antennas involved is high.

Joint Channel and Information Estimation on Symbol Decomposition-Based Secure Point-to-Point Communications

“…In this method, we decompose sixteen Quadrature Amplitude Modulation (16-QAM) symbol into four Binary Phase Shift Keying (BPSK) symbols and amplify all the four components in four transmitting antenna and beamforms all the components simultaneously through a single channel. The receiver receives all the components as a single 16-QAM symbol [3]. In this paper, we decompose 16-QAM symbol into four BPSK symbols instead of 2 QPSK symbols, since using BPSK will have low envelop as compared to using QPSK.…”

“…In this paper, we decompose 16-QAM symbol into four BPSK symbols instead of 2 QPSK symbols, since using BPSK will have low envelop as compared to using QPSK. Also, based on the results from [3] in terms of security aspects, we use BPSK.…”

“…This technique is robust and gives accurate estimates but consumes higher energy as compared to other techniques and this excess energy can be harvested from the superimposed signal at the receiver by using power splitting based simultaneous wireless power and information transmission technique (PS-SWIPT) with an power splitting circuit [9], [10]. The physical layer security aspects of the decomposition-based transmitter were already explained in [3]. Thus, in this paper we focus on energy efficiency and channel estimation technique with IB-DFE receiver.…”

Massive MIMO Techniques for 5G and Beyond—Opportunities and Challenges

“…As these systems expand in different domains (power, antennas, terminals, base stations), power consumption would have grown in an unacceptable manner by using the classical techniques. New architectures and approaches are being developed with the energy efficiency goal [2][3][4][5][6]. The spark in the research and development of MIMO systems was inspired by the work of Foschini [7] and Telatar [8], with results showing a steep linear increase in channel capacity with the increasing number of antennas being presented.…”