Mangang Xie

Secure massive MIMO-enabled full-duplex 2-tier heterogeneous networks by exploiting in-band wireless backhauls

To enhance the spectrum efficiency and secrecy performance, by using in-band full-duplex (FD) wireless backhaul technique, a secure massive multiple input multiple output (MIMO)–enabled heterogeneous cellular network (HCN) model is presented, where the macro base stations (MBSs) are equipped with massive MIMO antenna array, whereas the small cell base stations (SBSs) and user equipment have the single antenna. The ultradense small cells underlay the macro cells and offload traffic from macro cells. With FD mode, the massive MIMO MBSs and single-antenna SBSs are responsible, respectively, for the access traffic of macro and small cells as well as the backhaul transmission between MBSs and SBSs over the same time-frequency resource. The transmissions of macro and small cells are exposed to non-colluding and passive eavesdroppers that attempt to decode the signals of legitimate users. For such HCN with in-band wireless backhaul, by modeling the network elements as the independent Possion point processes and using the stochastic geometry, we first investigate the secrecy probabilities of the macro cell downlink and small cell uplink transmissions. At the same time, to achieve a comprehensive view, we also investigate the corresponding signal-interference-noise ratio (SINR) coverage performance. The presented numerical results show that when the intensity of user equipment is small relatively, exploiting the in-band backhaul interference as jamming signals can enhance the secrecy probabilities of both the macro and small cell transmissions so that the in-band FD backhaul mode outperforms the out-band FD one. However, for the SINR coverage, the opposite results are achieved. That is to say, the in-band backhaul transmission degrades the SINR coverage probabilities because of the existence of wireless backhaul interference. Besides of these, in numerical analysis, we also investigate the effect of the network parameters on the secrecy and coverage performance of both the macro and small cells. The derived results can be used for guiding the design of HCNs.

Full-duplex massive MIMO AF relaying system with low-resolution ADCs under ZFT/ZFR scheme

This paper investigates the multi-user full-duplex massive multiple-input multiple-output (MIMO) amplify-and-forward (AF) relaying system with low-resolution analog-to-digital converts (ADCs), where the zero-forcing transmitting/ zero-forcing receiving (ZFT/ ZFR) precoding scheme is employed. By modeling the loop-interference and quantization noise as additive noise, we perform the analysis of the achievable spectral efficiency (SE) that is given with closed-form expressions. Then, we present the asymptotic analyses under three different power-scaling scenarios. Comparison analysis shows that, with different power-scaling schemes, the system has different ability to restrict the effect of loop interference and low-resolution ADCs. Specially, the impact of loop interference and quantizer errors on achievable SE is restricted effectively only under the power-scaling scenario where the relays transmit power is scaled down with the number of transmit antennas at relay. At the same time, the effect of loop interference can be also restricted under the case where both the transmit powers at sources and relay are scaled down with the relays antenna number. The results can be used to guide the design of massive MIMO relaying systems so that the hardware cost and energy consume can be deduced significantly.

Effect of low-resolution ADCs and loop interference on multi-user full-duplex massive MIMO amplify-and-forward relaying systems

This paper focuses on a multi-user full-duplex massive multiple-input multiple-output amplify-and-forward relaying system with low-resolution analogue-to-digital convertors (ADCs). By modelling the loop-interference and quantisation noise as additive noise, we perform the analyses of the achievable spectral efficiency (SE) by considering the two canonical processing schemes, maximum ratio combining/maximal ratio transmission (MRC/MRT) and zero-forcing receive/zero-forcing transmission (ZFR/ZFT), respectively. Specially, we first obtain the tractable closed-form expressions of the achievable SE. Then, we present the asymptotic analyses under three different power-scaling scenarios. Comparison analysis shows that the low-resolution quantisers impose more performance loss on ZFR/ZFT schemes than MRC/MRT ones. At the same time, it is found that with different power-scaling schemes, the systems have different capabilities to restrict the effect of loop interference and low-resolution ADCs. Specially, the impact of both the loop-interference and quantisers on achievable SE can be restricted effectively only under the power-scaling scenario where the relays transmission power is scaled down with the number of transmit antennas and the sources’ transmission power is fixed. For the power-scaling case where the transmission powers of both relay and sources are scaled down simultaneously with the number of antennas, only the effect of the loop interference can be restricted, but the one of low-resolution quantisers remains.

Study on energy efficiency of D2D underlay massive MIMO networks with power beacons

This paper focuses on energy efficiency of device-to-device (D2D) underlay massive multiple-input multiple-output (MIMO) hybrid networks with power beacons (PBs). The D2D transmitters harvest the energy from the signals of dedicated power beacons, but also the ambient radio frequency (RF) interference of cellular users (CUs). The inverse power control schemes are employed at D2D transmitters. For the proposed hybrid network, we model the positions of CUs, D2D users (DUs), and PBs as the independently Poisson point processes (PPPs), respectively. By applying stochastic geometry, we present the energy harvesting scheme and derive the sufficient probability that a typical D2D transmitter harvests sufficient energy to establish communication links. Both the analytical and numerical results show that exploiting the ambient RF interference is an effective alternative to enhance the sufficient probability of D2D communications.

Min–Max User-Pair Association Criterion and Outage Performance of K-Tier Relay-Based Heterogeneous Networks

This paper focuses on the user-pair association for multi-tier relay-based dual-hop heterogeneous networks (HetNets) and proposes a novel min–max user-pair association (MM-UPA) criterion by integrating the bias factors, which is an evolution of conventional single-hop user association based on receive signal strength (RSS). The core idea of the proposed MM-UPA is that, in each tier the nearest relay to a typical user-pair is characterized by the maximum of the RSS reciprocals

Analysis of non-best user association scheme in K-tiers heterogeneous networks

{1 / {P_{SR}^{j} }}

Optimal Design of Secrecy Massive MIMO Amplify-and-Forward Relaying Systems With Double-Resolution ADCs Antenna Array

1/PSRj and