Multi-User Massive MIMO and Physical Layer Network Coding

Abstract

In this paper, we investigate the feasibility of applying Physical Layer Network Coding (PNC) in Multi-user Massive MIMO systems. In addition, we investigate the performance benefits of the joint Massive MIMO and PNC scheme. PNC has the potential of increasing capacity of a wireless system as the number of timeslots required for end-to-end communication reduces. We adopted a scheme that transforms the channel between a massive-antenna relay and a multitude of multi-antenna user terminals, with a Sum-Difference (SD) matrix. Through Log-Likelihood Ratio (LLR), PNC is achieved by deriving the network coded symbols from the estimates of the SD symbols at the massive-antenna relay node. The equalization matrix for the estimation is based on the SD transformed channel coefficient matrix. The error performance of the proposed joint Massive MIMO and PNC is evaluated through extensive simulation results. It is shown that joint Massive MIMO and PNC performs significantly better than Massive MIMO without PNC for QPSK modulation.

The Resilience of Massive MIMO PNC to Jamming Attacks in Vehicular Networks

“…Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) detectors are the main focus with respect to linear detectors. They are known to have desirable computational complexity and are proven to perform well in Massive MIMO networks [27]. We also assume that there is a perfect channel state information (CSI) at the BS (i.e., the channel matrix H is known at the receiver (BS)).…”

“…As already stated in previous sections, in [27], we developed a Massive MIMO PNC algorithm, where a multi-antenna BS estimates PNC symbols from received interfered symbols, which are composed of superimposed transmitted symbols from multi-user multi-antenna UEs. The concept is based on a linear transformation of the channel between the BS and the UEs, using a sum-difference (SD) matrix, under the assumption that channel is known to the BS.…”

“…Unfortunately, some forms of interference are intentional and uncontrollable. communication system with the objective of sabotaging the normal operation of the network [27].…”

“…In our recently published work [27], we developed a practical approach for deploying PNC in multi-user Massive MIMO systems, utilizing QPSK modulation scheme. In this Massive MIMO PNC work, we formulated a Maximum a Posteriori (MAP) based PNC mapping scheme, leveraging on the existing MIMO's linear detectors such as Zero-Forcing (ZF) and Minimum Mean Square Error (MMSE).…”

Optimized Antenna Selection and Adaptive Power Allocation for Physical Layer Network Coding with Selective Soft-Message-Forward Cooperation

“…Then, it mapped the superposition signals into the log-likelihood ratio (LLR) metrics. It retained the reliability metrics contained in the superposition signals, which were beneficial to the decoding in the BC stage [12]. However, the SMF scheme required much higher symbol synchronization and mapping algorithm complexity when compared with those of the AF one.…”