A pair of terminals exchanging information via a layer of parallel relay nodes under slow fading is considered. Two protocols are proposed based on the combination of opportunistic relaying (OR) with analoguenetwork ...
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A pair of terminals exchanging information via a layer of parallel relay nodes under slow fading is considered. Two protocols are proposed based on the combination of opportunistic relaying (OR) with analogue network coding (ANC), named ORANC, or with digital networkcoding (DNC), named ORDNC, respectively. Two schemes/versions of ORDNC, including 2-phase ORDNC (2P-ORDNC) and 3-phase ORDNC (3P-ORDNC) are proposed. Their outage performances are investigated. ORANC and 2P-ORDNC are proved to achieve optimal diversity-multiplexing tradeoff (DMT), whereas 3P-ORDNC is proved to be suboptimal. However, from diversity viewpoint only, all the above schemes are proven to achieve full diversity order. Simulation results verify the analysis, and show that 3P-ORDNC and ORANC shows advantage at low-and high-data rate regions, respectively.
Wireless communication using existing coding models poses several challenges for RF signals due to multipath scattering, rapid fluctuations in signal strength and path loss effect. Unlike existing works, this study pr...
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Wireless communication using existing coding models poses several challenges for RF signals due to multipath scattering, rapid fluctuations in signal strength and path loss effect. Unlike existing works, this study presents a novel coding technique based on analogue network coding (ANC) in conjunction with Space Time Block coding (STBC), termed as Space Time analogue network coding (STANC). STANC achieves the transmitting diversity (virtual MIMO) and supports big data networks under low transmitting power conditions. Furthermore, this study evaluates the impact of relay location on smart devices network performance in increasing interfering and scattering environments. The performance of STANC is analyzed for Internet of Things (IoT) applications in terms of Symbol Error Rate (SER) and the outage probability that are calculated using analytical derivation of expression for Moment Generating Function (MGF). In addition, the ergodic capacity is analyzed using mean and second moment. These expressions enable effective evaluation of the performance and capacity under different relay location scenario. Different fading models are used to evaluate the effect of multipath scattering and strong signal reflection. Under such unfavourable environments, the performance of STANC outperforms the conventional methods such as physical layer networkcoding (PNC) and ANC adopted for two way transmission.
This study presents the performance analysis of multiple-antenna two-way amplify-and-forward relay network in an interference-limited environment. To avoid the high feedback overhead and to fully exploit a multiple-an...
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This study presents the performance analysis of multiple-antenna two-way amplify-and-forward relay network in an interference-limited environment. To avoid the high feedback overhead and to fully exploit a multiple-antenna diversity, the authors employ transmit and receive antenna selection at the user node and analog networkcoding at the relaying node. Specifically, they formulate the exact expressions of the generalised signal-to-interference-plus-noise ratio (SINR). On the basis of the derived SINR, the upper-bounded cumulative distribution function is obtained. Subsequently, the outage probability (OP) and symbol error rate (SER) are determined and investigated. To assess the overall performance of the system, they present approximate but simple expressions for the overall OP (OOP) and overall SER. To gain insights, asymptotic expressions of OP and OOP are provided, which enable the characterisation of the achievable coding gain and diversity order of the system. Besides, they derive upper bounds on the achievable rate based on Jensen's inequality. Furthermore, they formulate three optimisation problems to minimise outage, namely optimal relay location under fixed power allocation, optimal power allocation under fixed relay location, and joint ORL and power allocation. Finally, the tightness of their analysis is attested through Monte Carlo simulation.
In the letter, a wireless energy harvesting (WEH) multicast network is proposed. Two source nodes communicate with their respective destination nodes via a WEH relay node. Adopting the power splitting relaying (PSR) p...
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In the letter, a wireless energy harvesting (WEH) multicast network is proposed. Two source nodes communicate with their respective destination nodes via a WEH relay node. Adopting the power splitting relaying (PSR) protocol and analogue network coding (ANC), the relay node simultaneously harvests the energy and receives the information from the signals transmitted by the two source nodes in the first time slot $\lpar T/2\rpar $(T/2), and retransmits the amplified signal to the destination nodes in the second time slot $\lpar T/2\rpar $(T/2) using all harvested energy. The analytical expressions of the ergodic sum-rate of the proposed network are derived. Numerical results corroborate the derived expressions and show that the proposed scheme nearly doubles the maximal ergodic sum-rate in comparison with the conventional unicast four time slots WEH scheme.
In this study, the authors investigate the impact of channel estimation error (CEE) on the performance of a multiple-input-multiple-output (MIMO) two-way relay system under Rayleigh fading. Herein, transmit/receive ze...
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In this study, the authors investigate the impact of channel estimation error (CEE) on the performance of a multiple-input-multiple-output (MIMO) two-way relay system under Rayleigh fading. Herein, transmit/receive zero-forcing (ZF) is employed at the two source nodes, whereas analogue network coding is used at the relay node. Fundamentally, for making use of transmit/receive ZF, all nodes must be aware of channel state information (CSI). As perfect CSI may not always be available in practical scenarios, the CEE does exist in the considered system. By taking the imperfect CSI into account, they enucleate that the residual self-interference and additional noise pertaining to the CEE have effect of reducing end-to-end signal-to-noise ratios (SNRs) at the two source nodes. Based on the statistical characterisations of these post-processing SNRs, they carry out the overall system outage probability analysis. Further, they investigate the asymptotic outage behaviour to deduce the achievable diversity order. They substantiate that the diversity order may reduce to zero under severe impact of CEE. In addition, they derive a closed-form expression of ergodic sum-rate of the considered system with CEE. Numerical and simulation investigations are conducted to support all the theoretical findings using various values of CEE and antenna configurations.
This paper studies the wireless two-way relay channel (TWRC), where two source nodes, S1 and S2, exchange information through an assisting relay node, R. It is assumed that R receives the sum signal from S1 and S2 in ...
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This paper studies the wireless two-way relay channel (TWRC), where two source nodes, S1 and S2, exchange information through an assisting relay node, R. It is assumed that R receives the sum signal from S1 and S2 in one time-slot, and then amplifies and forwards the received signal to both S1 and S2 in the next time-slot. By applying the principle of analogue network coding (ANC), each of S1 and S2 cancels the so-called "self-interference" in the received signal from R and then decodes the desired message. Assuming that SI and S2 are each equipped with a single antenna and R with multi-antennas, this paper analyzes the capacity region of the ANC-based TWRC with linear processing (beamforming) at R. The capacity region contains all the achievable bidirectional rate-pairs of S1 and S2 under the given transmit power constraints at SI, S2, and R. We present the optimal relay beamforming structure as well as an efficient algorithm to compute the optimal beamforming matrix based on convex optimization techniques. Low-complexity suboptimal relay beamforming schemes are also presented, and their achievable rates are compared against the capacity with the optimal scheme.
A parallel interference cancellation (PIC) based signal detection scheme is proposed for asynchronous bidirectional relay networks using analog networkcoding (ANC) with differential modulation. It is shown that the p...
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A parallel interference cancellation (PIC) based signal detection scheme is proposed for asynchronous bidirectional relay networks using analog networkcoding (ANC) with differential modulation. It is shown that the proposed scheme can effectively suppress the inter-symbol interference (ISI) in the received mixed signals at the relay node in the first transmission time-slot and offers significant performance improvement when neither the source nodes nor the relay knows the channel state information, and still retains a low computational complexity(1).
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