Performance analysis of SWIPT relay networks with noncoherent modulation

In this paper, we investigate the performance of noncoherent modulation in simultaneous wireless information and power transfer (SWIPT) relay networks. Noncoherent modulation schemes eliminate the need for instantaneous channel state information (CSI) estimation, and therefore, minimise the overall energy consumption of the network. In particular, we adopt a moments-based approach to develop a comprehensive novel analytical framework for the analysis of the outage probability, achievable throughput, and average symbol error rate (ASER) of a dual-hop SWIPT relay system considering the time switching (TS) and power splitting (PS) receiver architectures. In addition, through the derivation of new asymptotic analytical results for the outage probability and ASER, we analytically demonstrate that the diversity order of the considered system is non-integer less than 1 in the high SNR regime. Our results show that there is a unique value for the PS ratio that minimises the outage probability of the system, while this is not the case for the TS protocol. We also demonstrate that, in terms of system throughput, the TS relaying scheme is superior to the PS relaying scheme at lower SNR values. An extensive Monte Carlo simulation study is presented to corroborate the proposed analytical model

A Novel Antenna Selection Scheme for Spatially Correlated Massive MIMO Uplinks with Imperfect Channel Estimation

We propose a new antenna selection scheme for a massive MIMO system with a single user terminal and a base station with a large number of antennas. We consider a practical scenario where there is a realistic correlation among the antennas and imperfect channel estimation at the receiver side. The proposed scheme exploits the sparsity of the channel matrix for the effective selection of a limited number of antennas. To this end, we compute a sparse channel matrix by minimising the mean squared error. This optimisation problem is then solved by the well-known orthogonal matching pursuit algorithm. Widely used models for spatial correlation among the antennas and channel estimation errors are considered in this work. Simulation results demonstrate that when the impacts of spatial correlation and imperfect channel estimation introduced, the proposed scheme in the paper can significantly reduce complexity of the receiver, without degrading the system performance compared to the maximum ratio combining.Comment: in Proc. IEEE 81st Vehicular Technology Conference (VTC), May 2015, 6 pages, 5 figure

A New Reduced-Complexity Detection Scheme for Zero-Padded OFDM Transmissions

Recently, zero-padding orthogonal frequency division multiplexing (ZP-OFDM) has been proposed as an alternative solution to the traditional cyclic prefix (CP)-OFDM, to ensure symbol recovery regardless of channels nulls. Various ZP-OFDM receivers have been proposed in the literature, trading off performance with complexity. In this paper, we propose a novel low-complexity (LC) receiver for ZP-OFDM transmissions and derive an upper bound on the bit error rate (BER) performance of the LC-ZP-OFDM receiver. We further demonstrate that the LC-ZP-OFDM receiver brings a significant complexity reduction in the receiver design, while outperforming conventional minimum mean-square error (MMSE)-ZP-OFDM, supported by simulation results. A modified (M)-ZP-OFDM receiver, which requires the channel state information (CSI) knowledge at the transmitter side, is presented. We show that the M-ZP-OFDM receiver outperforms the conventional MMSE-ZP-OFDM when either perfect or partial CSI (i.e., limited CSI) is available at the transmitter side.Index Terms-Zero-padding, orthogonal frequency division multiplexing (OFDM), equalization

Solutions to Integrals Involving the Marcum Q-Function and Applications

Novel analytic solutions are derived for integrals that involve the generalized Marcum Q-function, exponential functions and arbitrary powers. Simple closed-form expressions are also derived for the specific cases of the generic integrals. The offered expressions are both convenient and versatile, which is particularly useful in applications relating to natural sciences and engineering, including wireless cpmmunications and signal processing. To this end, they are employed in the derivation of the channel capacity for fixed rate and channel inversion in the case of correlated multipath fading and switched diversity.Comment: 15 Pages, 2 Figure

RF-Powered Cognitive Radio Networks: Technical Challenges and Limitations

The increasing demand for spectral and energy efficient communication networks has spurred a great interest in energy harvesting (EH) cognitive radio networks (CRNs). Such a revolutionary technology represents a paradigm shift in the development of wireless networks, as it can simultaneously enable the efficient use of the available spectrum and the exploitation of radio frequency (RF) energy in order to reduce the reliance on traditional energy sources. This is mainly triggered by the recent advancements in microelectronics that puts forward RF energy harvesting as a plausible technique in the near future. On the other hand, it is suggested that the operation of a network relying on harvested energy needs to be redesigned to allow the network to reliably function in the long term. To this end, the aim of this survey paper is to provide a comprehensive overview of the recent development and the challenges regarding the operation of CRNs powered by RF energy. In addition, the potential open issues that might be considered for the future research are also discussed in this paper.Comment: 8 pages, 2 figures, 1 table, Accepted in IEEE Communications Magazin

Secrecy outage analysis for Alamouti space-time block coded non-orthogonal multiple access

This letter proposed a novel transmission technique for physical layer security by applying the Alamouti Space-Time Block Coded Non-orthogonal Multiple Access (STBC-NOMA) scheme. The secure outage performance under both perfect successive interference cancellation (pSIC) and imperfect successive interference cancellation (ipSIC) are investigated. In particular, novel exact and asymptotic expressions of secrecy outage probability are derived. Numerical and theoretical results are presented to corroborate the derived expressions and to demonstrate the superiority of STBC-NOMA and its ability to enhance the secrecy outage performance compared to conventional NOMA

On the Performance of Non-Orthogonal Multiple Access Systems with Imperfect Successive Interference Cancellation

Non-orthogonal multiple access (NOMA) technique has sparked a growing research interest due to its ability to enhance the overall spectral efficiency of wireless systems. In this paper, we investigate the pairwise error probability (PEP) performance of conventional NOMA systems, where an exact closed form expression for the PEP is derived for different users, to give some insight about the reliability of the far and near users. Through the derivation of PEP expressions, we demonstrate that the maximum achievable diversity order is proportional to the user's order. The obtained error probability expressions are used to formulate an optimization problem that minimizes the overall bit error rate (BER) under power and error rate threshold constrains. The derived analytical results, corroborated by Monte Carlo simulations, are presented to show the diversity order and error rate performance of each individual user