New interference alignment schemes with full and half‐duplex relays for the quasi‐static X channel

Abstract

In this study, two relay-aided interference alignment (IA) schemes are proposed for the quasi-static M × 2 X channel where M is the number of transmitters and two is the number of receivers, respectively. The first scheme utilises one full-duplex relay and the second one utilises two half-duplex relays. In the proposed schemes, the transmitters transmit signals in every time slot and the relays operate in the amplify-and-forward (AF) mode. By verifying the linear independence between the desired signals and the interference, it is shown that the proposed schemes can achieve 2M/(M + 1) degrees of freedom (DoF) which is the maximum DoF for the M × 2 X channel. It is also shown by using the concept of reciprocity that the proposed IA schemes are applicable to the 2 × M X channel. Finally, through the numerical analysis, it is confirmed that the proposed IA schemes provide good alternatives to the previously known relay-aided IA scheme.

A Novel High Bandwidth Efficiency Interference Alignment Scheme Based on Continuous Phase Modulation

“…The equivalent base band signal of the lth data stream of the kth user can be expressed as: (10) where E, T, and , kl  represent the symbol energy, symbol period, and the information-bearing phase, respectively. The relationship between the phase and bit stream can be depicted as: (11) where h and q(t) represent the modulation index and phase pulse function, respectively. q(t) is the integral of the frequency pulse function f(t), which satisfies the following conditions:…”

“…In addition, Zhao et al have conducted a review on the Opportunistic Communications based IA in [9], and proposed a simultaneous wireless information and power transfer scheme to improve the quality of service (QoS) of IA networks. Due to the significant advantages, IA has been applied to the relay networks [10], [11], cognitive radio [12], [13], and green communications [14], [15].…”

A Novel Joint Spatial-Code Clustered Interference Alignment Scheme for Large-Scale Wireless Sensor Networks

“…In addition, the conclusions above were verified experimentally over the measured MIMO orthogonal frequency division-multiplexing (OFDM) channels in [ 6 ], and the viability of IA was substantiated. Due to its excellent performance in suppressing interference and increasing the throughput, IA has been applied to relay networks [ 7 ], cognitive radio [ 8 ], ad-hoc networks [ 9 ], etc. In particular, Pandey et al have validated the feasibility of IA in sensor networks in [ 10 ].…”