Outage Analysis for Full-Duplex Cooperative Networks with Optimal Relay Selection

An efficient technique used to prolong the lifetime of energy-constrained networks is energy harvesting (EH). In this paper, we investigate and develop the energy allocation methods for the relaying networks, in which opportunistic multiple relay selection schemes with both the full-duplex (FD) and half-duplex (HD) scheme for both EH and non-EH in decode-and-forward (DF) relaying mode. In addition, there are two policies proposed in this paper: (1) Max-Min with Self Interference Relay Selection (MMSI); (2) Max-Min Relay Selection (MMSR) are depicted for both EH and Non-EH relaying modes. Particularly, we derive closed-form expressions of outage probability to analyze the performance of systems. In addition, we propose the impact of self-interference on both policies to provide a practical insight. The results in numerical analysis reveal that the proposed MMSI scheme outperforms the MMSR mode in terms of outage probability.

In this paper, a new relaying scheme, referred to as space full-duplex max-max relay selection (SFD-MMRS) is proposed. SFD-MMRS uses relay selection and half-duplex (HD) relays with buffers to mimic full-duplex (FD) relaying. It allows the selection of different relays for reception and transmission, which in turn enables simultaneous reception and transmission. With SFD-MMRS the pre-log factor 1 over 2 is removed from the capacity expression and better performance in terms of throughput is achieved compared to the existing schemes. We provide a comprehensive analysis of the capacity of the proposed scheme for a decode-and-forward (DF) protocol in Rayleigh fading. Our simulation results show that the capacity of the proposed scheme with HD relays exceeds twice the capacity of the best relay selection (BRS) scheme with HD relays.

This paper investigates the integration of relay-assisted Internet of Things (IoT) systems, focusing on the use of multiple relays to enhance the system performance. The central metric of interest in this study is system outage probability, evaluated in terms of latency. Our research provides a comprehensive analysis of system outage probability, considering different relay selection criteria to optimize the system’s transmission performance. Three relay selection strategies are employed to enhance the system transmission performance. Specifically, the first strategy, optimal relay selection, aims to identify the relay that minimizes the latency and maximizes the data transmission reliability. The second approach, partial relay selection, focuses on selecting a subset of relays strategically to balance the system resources and achieve the latency reduction. The third strategy, random relay selection, explores the potential of opportunistic relay selection without prior knowledge. Through a rigorous investigation, our paper evaluates the impact of these relay selection criteria on the performance of relay-assisted edge computing systems. By assessing the system outage probability in relation to latency, we provide valuable insights into the trade-offs and advantages associated with each selection strategy. Our findings contribute to the design and optimization of reliable and efficient edge computing systems, with implications for various applications, including the IoT and intelligent data processing.

Relay and jammer selection schemes for improving physical layer security in two-way cooperative networks

In recent years, the MIMO-based underwater acoustic (UWA) wireless sensor networks have attracted significant research attention because of its wide and critical applications in marine research, oceanography, marine commercial operations, offshore oil industry, and defense systems. The cooperative-communications-based wireless relay networks have been widely cited as a very efficient technique to enhance the transmission and lifespan performances of the wireless networks. However, how to make the energy-efficient relay selection in the MIMO-based UWA wireless sensor networks, particularly under the harsh underwater wireless environments with the stringent power supply constraint, have been not well understood, neither thoroughly studied. To overcome the above problems, in this paper we propose the optimal relay selection scheme to minimize the energy consumption while guaranteeing the quality of service (QoS) of each link over the MIMO-based UWA cooperative wireless sensor networks. We use the Finite-state Markov chain to model the UAW channel. Moreover, we also incorporate MIMO multiplexing-gain and diversity-gain techniques, as well as residual relay energy in the relay selection process. We implement our proposed optimal relay selection scheme by the linear programming (LP) technique. We conduct the simulations to validate and evaluate our proposed scheme, showing its superlatives over the other existing schemes.

We study relay selection in both decode-and-forward (DF)-based and amplify-and-forward (AF)-based cooperative diversity networks consisting of a source, multiple relays, and a destination in the presence of multiple interferers, where each terminal has a single antenna and operates in half-duplex mode. In the network, it is assumed that the multiple interferers locate near the destination and far away from relays; thus, only the destination receives interfering signals, which is referred to as the interference-limited destination. Specifically, we first propose relay selection to maximize the mutual information on cooperative networks with the interference-limited destination. Then, for relay selection of DF-based networks, we derive the exact outage probability. Finally, for relay selection of AF-based networks, we derive the exact outage probability in integral form and its closed-form lower bound.

This paper studies on the relaying selective matter in amplify-and-forward (AF) cooperation communication with full-duplex (FD) activity. Various relay choice models supposing the present of different instant information are investigated. We examine a maximal relaying choice that optimizes the instant FD channel capacity and asks for global channel state information (CSI) as well as partial CSI learning. To make comparison easy, accurate outage probability clauses and asymptote form of these strategies that give a diversity rank are extracted. From that, we can see clearly that the number of relays, noise factor, the transmittance coefficient as well as the information transfer power had impacted on their performance. Besides, the optimal relay selection (ORS) model can promote than that of the partial relay selection (PRS) model.

In this paper, a decode-and-forward cooperative interference-limited multiple relay network is considered. An efficient relay selection strategy and its performance analysis are proposed, where only the relay nodes are affected by multiple interferences. In the proposed relay selection scheme, the selected relay is not always used, depending on the power of interferences and the channel state information of all links, while the direct path between source and destination is always used. For analytical tractability the distribution of interference-limited channel is approximated as an exponential distribution with high accuracy. Analysis of cooperative networks with interference-limited relays can be performed using the approximate exponential distribution by the same methods which have been used without interferences. We derive the bit error probability and outage probability of the proposed opportunistic max-min relay selection (OMRS) scheme in independent non-identically distributed Rayleigh fading channels. Numerical results present the superiority of OMRS over the conventional relay selection scheme which always uses the selected relay path. The exactness of the approximate analysis for interference-limited relays is also shown in numerical results.

This paper investigates the impact of relay selection (RS) on the performance of cooperative non-orthogonal multiple access (NOMA), where relays are capable of working in either full-duplex (FD) or half-duplex (HD) mode. A number of relays (i.e., K relays) are uniformly distributed within the disc. A pair of RS schemes are considered insightfully: 1) single-stage RS (SRS) scheme; and 2) two-stage RS (TRS) scheme. In order to characterize the performance of these two RS schemes, new closed-form expressions for both exact and asymptotic outage probabilities are derived. Based on analytical results, the diversity orders achieved by the pair of RS schemes for FD/HD cooperative NOMA are obtained. Our analytical results reveal that: 1) the FD-based RS schemes obtain a zero diversity order, which is due to the influence of loop interference at the relay; and 2) the HD-based RS schemes are capable of achieving a diversity order of K , which is equal to the number of relays. Finally, simulation results demonstrate that: 1) the FD-based RS schemes have better outage performance than HD-based RS schemes in the low signal-to-noise ratio (SNR) region; 2) as the number of relays increases, the pair of RS schemes considered are capable of achieving the lower outage probability; and 3) the outage behaviors of FD/HD-based NOMA SRS/TRS schemes are superior to that of random RS and orthogonal multiple access based RS schemes.

In the presence of an illegitimate user, we investigate the secrecy outage probability (SOP) of the optimal relay selection (ORS) networks by applying decode-and-forward (DnF) based full-duplex (FD) relaying mode. The closed-form expressions for the allocations of the end-to-end signal-to-interference-plus-noise ratio (SINR) in each wireless network are derived as well as the closed-form expression for the exact SOP of the proposed ORS system is presented under Rayleigh fading schemes. As an important achievement, SOP is also compared between orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) schemes. Our results reveal that the SOP of the suggested scheme can be considerably influenced by several parameters involved, including the number of relays, the average signal-to-noise ratio (SNR) of eavesdropper links, transmit power and the average residual self-interference (SI) enforced on the FD relays.DOI: http://dx.doi.org/10.5755/j01.eie.24.4.21483

Energy harvesting (EH) structure based on the ambient wireless communication technique, has lastly carried out the development approach to widen the existing time of the wireless networks. The energy collecting composition for the half duplex and full duplex wireless networks is examined. By employing the time switching-based relaying (TSR) networks and the Decode-and-Forward (DF) structure, we imply the approximated section of the operation probability and then estimate the throughput of the half-duplex and full-duplex wireless networks. We can see an essential outcome clearly based on the position of relaying, the achievement rate, the noise at the source and the relay as well as the energy transition component in TSR, effect on their outage possibility and throughput. Ultimately, the performances of the full-duplex (FD) and half-duplex (HD) wireless network architectures is different, the results are collected to demonstrate that, for a normal maximal networks, sometimes, FD one are more optimal than HD model and contrariwise, for instance, when the distance between the relay and the transmitter isn’t great, The outage possibility of the HD model is better than FD one. Or when rises \(\eta \), the HD throughput becomes better etc. With the same method, we also get the results illustrate that DF of two antennas is better than that of one antenna. Consequently, based on the practical condition, we determine what model is better.

This paper has investigated a downlink non-orthogonal multiple access (NOMA) cooperative scheme with user-assisted relaying, where near users are viewed as decode-and-forward (DF) relays operating full/half-duplex mode to assist multiple far users. Especially, the impact for the randomness of users location on the system performance has also been studied. Further, to overcome the zero diversity gain inherent to full-duplex (FD) operation, the direct link between a base station (BS) and each far user is exploited. The comprehensive performance analysis is conducted through the closed-form expressions in terms of outage probability, the diversity gain, system throughput, and ergodic sum rate. With respect to outage behavior, throughput, and ergodic sum rate, FD-based NOMA outperforms half-duplex (HD) NOMA in the lower signal-to-noise ratio (SNR) region. However, with the negative influence brought by residual loop-interference (LI), the advantage of FD NOMA scheme is not pronounced enough in the high SNR regime. Therefore, according to different SNR levels, we further propose a hybrid relaying scheme that switches opportunistically between the FD and HD modes. Afterward, the mode switching threshold is characterized such that the outage probability of each user is minimized. The simulation results confirm the correctness of our analysis and offer a significant guideline for system design in practice.

We propose in this paper, a strategy to minimize the total transmit power in a decode-and-forward (DF) multi-user, multi-relay cooperative uplink, such that each user satisfies its data rate. The base station performs optimal relay selection and also allocates optimal source and relay transmit powers by using the proposed algorithm. The relay selection is based upon the instantaneous user to base station channels, inter-user channels and also the target rates of the users. The simulation results indicate significant power savings over a non-cooperative uplink, under proposed joint relay selection and power minimization algorithm in a DF cooperative uplink when using a space-time coded cooperative diversity.

Multi-antenna relay assisted NOMA network with multiple imperfect factors

A novel cross-layer joint relay selection and power allocation (CL-JRSPA) scheme over physical layer and data-link layer is proposed for cooperative relaying system in this paper. Our goal is finding the optimal relay selection and power allocation scheme to maximize system achievable rate when satisfying total transmit power constraint in physical layer and statistical delay quality-of-service (QoS) demand in data-link layer. Using the concept of effective capacity (EC), our goal can be formulated into an optimal joint relay selection and power allocation (JRSPA) problem to maximize the EC when satisfying total transmit power limitation. We first solving optimal power allocation (PA) problem with Lagrange multiplier approach, and then solving optimal relay selection (RS) problem. Simulation results demonstrate that CL-JRSPA scheme gets larger EC than other schemes when satisfying delay QoS demand. In addition, the proposed CL-JRSPA scheme achieves the maximal EC when relay located approximately halfway between source and destination, and EC becomes smaller when the QoS exponent becomes larger.