Full-Duplex Massive MIMO Multi-Pair Two-Way AF Relaying: Energy Efficiency Optimization

Abstract

We consider two-way amplify and forward relaying, where multiple full-duplex user pairs exchange information via a shared full-duplex massive multiple-input multiple-output (MIMO) relay. Most of the previous massive MIMO relaying works maximize the spectral efficiency (SE). By contrast, we maximize the non-convex energy efficiency (EE) metric by approximating it as a pseudo-concave problem, which is then solved using the classic Dinkelbach approach. We also maximize the EE of the least energy-efficient user relying on the max-min approach. For solving these optimization problems, we derive closedform lower bounds for the ergodic achievable rate both for maximal-ratio combining and zero-forcing processing at the relay, by using minimum mean squared error channel estimation. We numerically characterize the accuracy of the lower bounds derived. We also compare the SE and EE of the proposed design to those of the existing full-duplex systems and quantify the significant improvement achieved by the proposed algorithm. We also compare the EE of the proposed full-duplex system to that of its half-duplex counterparts, and characterize the self-loop and inter-user interference regimes, for which the proposed full-duplex system succeeds in outperforming the half-duplex ones.

A Scalable Energy vs. Latency Trade-Off in Full-Duplex Mobile Edge Computing Systems

“…The optimization problem (8) is non-convex and in general difficult to solve partly due to the fractional objective functions. In order to solve (8), in the following we develop a tractable approach to obtain the optimal resource allocation in an iterative manner.…”

“…In [7], a joint design for precoding and decoding in a multi-antenna FD relay system was studied to maximize the end-to-end system performance. The spectral and energy efficiency maximization problems in a FD massive multple-input multiple-output (MIMO) relay system were studied in [8]. In contrast to the above works, which are all based on the concept of the traditional interference suppression, where, multi-user interference (MUI) is treated as unwanted, a multi-user FD system was studied in [9]- [11] by exploiting the downlink MUI rather than suppressing it.…”

Analysis of Quantized MRC-MRT Precoder For FDD Massive MIMO Two-Way AF Relaying

“…Remark 7: Equation (18) shows that the rate of convergence ofR I i ′ to zero does not depend on any particular (i ′ , i) receiver-transmitter pair. Hence,R I i ′ converges uniformly to 0 for all users.…”

“…A massive MIMO system is potentially capable of improving the sumrate and the energy-efficiency (EE) of wireless systems [10], [11]. Recently, massive MIMO technology has also been incorporated in TWR by employing a large number of antennas at the relay [12]- [18]. Cui et al [12] constructed a precoder for the relay based on MRT and maximal ratio combining (MRC).…”

“…Naghsh et al [17] maximized the sum-rate of MIMO-aided TWR amplify-and-forward (AF) networks using a novel minorization-maximization based iterative algorithm. Reference [18] recently optimized the energy efficiency of a two-way AF massive MIMO relay.…”