Cooperative Communication Scheme Research Articles

Cooperative Smartphone Relay Selection Based on Fair Power Utilization for Network Coverage Extension

This paper presents a relay selection algorithm based on fair battery power utilization for extending mobile network coverage and capacity by using a cooperative communication strategy where mobile devices can be utilized as relays. Cooperation improves the network performance for mobile terminals, either by providing access to out-of-range devices or by facilitating multi-path network access to connected devices. In this work, we assume that all mobile devices can benefit from using other mobile devices as relays and investigate the fairness of relay selection algorithms. We point out that signal strength based relay selection inevitably leads to unfair relay selection and devise a new algorithm that is based on fair utilization of power resources on mobile devices. We call this algorithm Credit based Fair Relay Selection (CF-RS) and in this paper show through simulation that the algorithm results in fair battery power utilization, while providing similar data rates compared with traditional approaches. We then extend the solution to demonstrate that adding incentives for relay operation adds clear value for mobile devices in the case they require relay service. Typically, mobile devices represent self-interested users who are reluctant to cooperate with other network users, mainly due to the cost in terms of power and network capacity. In this paper, we present an incentive based solution which provides clear mutual benefit for mobile devices and demonstrate this benefit in the simulation of symmetric and asymmetric network topologies. The CF-RS algorithm achieves the same performance in terms of achievable data rate, Jain’s fairness index and utility of end devices in both symmetric and asymmetric network configurations.

LDPC-based Joint Source Channel Coding and Decoding Strategies for single relay cooperative communications

This paper investigates new cooperative communication strategies based on Low-Density Parity-Check codes (LDPC) with Joint Source-Channel (JSC) coding and decoding algorithms to efficiently deliver a correlated content to a destination node. The proposed strategies rely on double LDPC codes where the source and the channel coding are similar to standard LDPC operations, and can be mapped on Tanner graphs for message-passing decoding. Three coding strategies are proposed where different LDPC source and channel coding setups are applied at the source node and the relay node. For each transmission strategy, we propose a graph mapping the whole network, over which iterative message-passing decoding is applied, and where the probability of errors in the source–relay link are taken into account. We showed, based on computer simulations, that the proposed strategies can provide substantial improvements compared to equivalent rates point-to-point systems. Simulation results also showed that the system performance depends on the relay position, and that adapting the source and the relay channel coding rates accordingly can enhance the overall system performance for a time-varying network.

Combine-and-forward: A linear cooperative multi-level communication strategy for distributed MIMO relays

This work analyzes cooperative networks in which a single source message is retransmitted by multiple levels of relays that are equipped with multiple antennas. In the considered scheme, each relay linearly combines its receptions from multiple antennas and multiple levels before adjusting its power and forwarding it. The proposed scheme outperforms the previously proposed methods that are based on decoding and forwarding in the low SNR regime. The contributions of this paper are two-fold: (i) it provides an analytical framework for the statistics of the accumulated signal and the accumulated noise as functions of network parameters such as noise level, power level, number of antennas, and multi-hop diversity for dense networks; (ii) it shows that the performance of multi-level networks can be improved simply by combining the receptions from the previous levels and multiple antennas in a linear fashion.

Research on Cooperative Communication Strategy and Intelligent Agent Directional Source Grouping Algorithms for Internet of Things

In order to improve the network layer of the Internet of things to improve transmission reliability, save time delay and energy consumption, the Internet of things cooperative communication and intelligent agent technology were studied in this paper. In cooperative communication, a new cooperative communication algorithm KCN (k-cooperative node), and a reliability prediction model are proposed. The k value is determined by the end-to-end reliability. After k cooperative nodes are selected, other nodes enter dormancy. In aggregate traffic allocation, game theory is used to model the traffic equilibrium and end-to-end delay optimization scenarios. In practice, the optimal duty cycle can be calculated, which makes some cooperative nodes enter an idle state to save energy. Under the premise of guaranteeing end-to-end delay, it is shown that the reliability of the proposed KCN algorithm is better than that of the other existing routing protocols. In the aspect of intelligent agent, a directional source grouping algorithm D-MIP is proposed. This algorithm studies the routing problem of multi-agent parallel access to multiple source nodes. A directed source packet multi-agent routing planning algorithm is proposed. The iterative algorithm of each source node is limited to a sector, and the optimal intelligent agent route is obtained by selecting an appropriate angle. Compared with other algorithms, it is shown through a lot of simulated results that energy consumption and time delay has been saved by the proposed D-MIP algorithm.

Joint Multicast Beamforming and Relay Design for Maritime Communication Systems

With growing human maritime activities, supporting low-cost and high-speed information services for users at sea has become imperative. However, traditional means of maritime communications fail to provide high rate services due to their high cost and limited bandwidth. In this paper, considering a base station ashore and several offshore relay nodes, we propose a cooperative multicast communication scheme for maritime users relying on joint beamforming (BF) optimization and relay design. Specifically, we decompose our proposed joint optimization problem into two subproblems, which can be solved by the feasible point pursuit successive convex approximation approach. Furthermore, an alternating optimization algorithm is proposed, which imposes an exponentially increasing complexity as a function of the number of BF elements and the number of relays, when aiming for finding the globally optimal solution. In order to reduce this excessive computational complexity, a low-complexity distributed algorithm is also conceived and its closed-form solution is derived. Finally, the simulation results provided show that our proposed algorithm is beneficial in terms of increasing both the throughput as well as the energy efficiency.

Efficient relay selection scheme utilizing superposition modulation in cooperative communication

In this paper, a cooperative communication scheme is proposed utilizing superposition modulation (SM) in orthogonal frequency division multiplexing (OFDM). The proposed relay selection scheme selects an optimal relay and improves the BER performance by utilizing SM in cooperative communication. Also, the proposed cooperative communication scheme transmits the signal of source and relay at the same time by utilizing SM. As a result, the proposed schemes select the optimal relay and improve the reliability and throughput compared with the conventional cooperative communication scheme.

Energy-Efficient Coalition Games with Incentives in Machine-to-Machine Communications

The need to achieve energy efficiency in machine-to-machine (M2M) communications has been a driver of the use of coalition game-based cooperative communication schemes. The proposed schemes have shown good energy-efficient performance results in the recent past. However, sustaining cooperation amongst coalition games of M2M devices from different network-operating authorities requires appropriate incentives. A review of the literature demonstrates that a limited number of contributions have considered the use of coalition games with incentives in M2M communications. In this paper, an energy-efficient coalition game with incentives in M2M communications is proposed. This work considers a Sierpinski triangle technique to partition M2M devices into multiple networks of hierarchical zones. Based on the constructed zones, a contract-modelled incentive is invoked to stimulate multihop transmissions between devices up to the BS/sink. The results obtained demonstrate that the proposed approach is on average 10% more energy efficient than the closely related existing algorithm, the coalition game theoretical clustering (CGTC).

Interference Mitigation for Ultrareliable Low-Latency Wireless Communication

This paper proposes interference mitigation techniques for provisioning ultrareliable low-latency wireless communication in an industrial automation setting, where multiple transmissions from controllers to actuators interfere with each other. Channel fading and interference are key impairments in wireless communication. This paper leverages the recently proposed ``Occupy CoW'' protocol that efficiently exploits the broadcast opportunity and spatial diversity through a two-hop cooperative communication strategy among distributed receivers to combat deep fading, but points out that because this protocol avoids interference by frequency division orthogonal transmission, it is not scalable in terms of bandwidth required for achieving ultrareliability, when multiple controllers simultaneously communicate with multiple actuators (akin to the downlink of a multicell network). The main observation of this paper is that full frequency reuse in the first phase, together with successive decoding and cancellation of interference, can improve the performance of this strategy notably. We propose two protocols depending on whether interference cancellation or avoidance is implemented in the second phase, and show that both outperform Occupy CoW in terms of the required bandwidth and power for achieving ultrareliability at practical values of the transmit power.

On the performance of two‐user full‐duplex network‐coded cooperation

SummaryIn this paper, we propose two schemes based on a full‐duplex network‐coded cooperative communication (FD‐NCC) strategy, namely, full‐duplex dynamic network coding (FD‐DNC) and full‐duplex generalized dynamic network coding (FD‐GDNC). The use of full‐duplex communication aims at improving the spectrum efficiency of a two‐user network where the users cooperatively transmit their independent information to a common destination. In the proposed FD‐NCC schemes, the self‐interference imposed by full‐duplexing is modeled as a fading channel, whose harmful effect can be partially mitigated by interference cancellation techniques. Nevertheless, our results show that, even in the presence of self‐interference, the proposed FD‐NCC schemes can outperform (in terms of outage probability) the equivalent half‐duplex network‐coded cooperative (HD‐NCC) schemes, as well as traditional cooperation techniques. Moreover, the ϵ‐outage capacity, that is, the maximum information rate achieved by the users given a target outage probability, is evaluated. Finally, we examine the use of multiple antennas at the destination node, which increases the advantage of the FD‐NCC (in terms of the diversity‐multiplexing trade‐off and ϵ‐outage capacity).

Performance Analysis of Distortion-Acceptable Cooperative Communications in Wireless Sensor Networks for Internet of Things

This paper analyzes the performance limit of cooperative communications in wireless sensor networks (WSNs), with the aim of utilizing the analytical results for practical applications, for example, Internet of Things (IoT). The observation of a primary sensor is not necessarily to be reconstructed losslessly, as long as the system can make correct judgements and operations. At first, we perform the theoretical analysis to derive an inner bound on the achievable rate-distortion region for the lossy communications with helpers. The numerical results precisely match the Wyner–Ziv theorem when there is only one assisting link and no rate constraint on the assisting link. Then, we present a distributed encoding and joint decoding scheme for cooperative communications in WSNs. Moreover, a series of simulations are conducted for the performance evaluation and verification. Although there is an obvious gap between the theoretical and simulation results, the performance curves show similar tendencies in terms of the signal-to-noise ratio versus bit error rate.

An Efficient Partner Selection Method to Overcome the Interference Effect in Wireless Networks

In this paper, through a mathematical analysis of the overall links capacity equation, we present an efficient partner selection criterion in a cooperative communication scheme with a time-varying fading channel and severe interference on the cooperative links to mitigate the interference effect without the need for additional power consumption to transmit the information signal. For the partner(s) selection, we examine different selection criteria based on minimizing the error rate and maximizing the end-to-end system capacity to collaborate in the delivery process. We prove that in the proposed relay scheme, a simple selection criterion independent of the interference state is a sufficient and efficient criterion for selecting the partners out of terminals suffering from interference. It is found that the use of a simple and efficient selection criterion for assigning multiple cooperating terminals is able to achieve a significant diversity gain, conserve the energy of individual terminals, and improve the error performance with low computational complexity, even in the absence of the interference state information. All of the theoretical findings are verified through simulation studies.

Accelerating Content Delivery via Efficient Resource Allocation for Network Coding Aided D2D Communications

Device-to-device (D2D) communication is one of the emerging paradigms in 5G networks to facilitate ever-increasing demands for local area services. For content delivery, direct transmission via D2D communications among proximity nodes and cooperative content downloading from base stations can enhance system capacity, which on the other hand cause interference to regular cellular networks due to spectrum sharing. Random linear network coding is capable of improving robustness to the varying channel state with severe interference. It also increases collaborative efficiency between users for content sharing. This paper investigates cooperative relaying scheme (RNCC) for cooperative D2D communications, which is aided by the random linear network coding. This is achieved by allocating the downlink resource among multiple cellular users, cooperative relays, and D2D pairs. First a binary integer linear programming-based resource allocation problem is modeled by introducing D2D pairs' clustering concept, which is an NP-hard problem. For the optimal solution, we leverage the branch-and-cut algorithm. While for large scale networks, we contributed a distributed QoS-aware greedy algorithm, which yields close to optimal solution. Our proposed schemes are evaluated via the extensive simulations considering practical scenarios, and the system sum rate results demonstrate an enhancement of ~20% performance in comparison with several other practical strategies in literature, which validates our schemes' effectiveness.

Proposal of Cooperative Communication to Enhance Accuracy of Wireless Control Systems

Control systems are being changed from wired to wireless communications because of flexibility, mobility and extensibility of wireless communication systems; however the reliability of wireless communications is suspected. In this paper, we propose cooperative communication scheme for wireless control systems which consist of a controller and multiple machines; these machines cooperatively work in a group and for the same duty. In the proposed method, the controller can communicate with machines directly or via other machines, whereas in the conventional method, the controller only communicates with machines directly. The simple 2-link arm plant is used to evaluate our proposed system, and the simulation results indicate that the proposed method is more accurate, and more stable than the conventional method.

An Energy Efficient Cooperative Communication Scheme in Ambient RF Powered Sensor Networks

The ambient radio frequency (RF) energy harvesting technology has recently been regarded as a potential solution for powering the wireless sensor networks (WSNs). However, the ultra-low power density of ambient RF energy is the main impediment to its further application. In this paper, we propose a novel energy efficient cooperative communication scheme (EECCS), which combines energy beamforming communication and ambient backscatter communication, to overcome the energy problem of WSNs powered by ambient RF energy harvesting. Moreover, to further reduce the energy consumption of nodes, we present an optimal resource allocation problem for EECCS. It can be formulated as a signomial geometric programming (SGP), which is nonconvex and NP-hard. We develop a Sequential Convex Approximation (SCA) algorithm for finding a solution of this SGP problem, which transforms the SGP problem into a sequence of geometric programming (GP) problems that are convex. The simulation results indicate that the EECCS can improve the energy efficiency of the ambient RF powered WSNs and maximize the total amount of data received by the sink.

A Cooperative Communication Scheme for Full-Duplex Simultaneous Wireless Information and Power Transfer Wireless Body Area Networks

In this article, we investigate the integration of simultaneous wireless information and power transfer as well as full-duplex (FD) in a two-tier wireless body area network (WBAN), where the FD relay can transfer energy to the sources, forward data to the destination, and receive data from the sources simultaneously. Considering the characteristics of WBANs, the average delay limited weighted throughput maximization problem is proposed, under the average queue stability, the long-term and short-term powerenergy, and the transmission rate constraints. An effective algorithm based on the Lagrange dual decomposition method is proposed. The simulation results show that our proposed scheme outperforms the existing scheme.

항공기용 멀티 홉 무선센서 통신망에서 협력통신기법

항공기용 멀티 홉 무선센서 통신망에서 협력통신기법

Research on Scalable Zigbee Wireless Sensor Network Expansion Solution

Zigbee technology has a wide range of applications in constructing wireless sensor networks which can increase the number of nodes in the Zigbee network that can be accommodated and expand the wireless sensor network’s network size and monitoring range. TI’s Z-Stack network protocol stack is used as the carrier for Zigbee technology. On the one hand, the information transfer strategy of the network is improved to increase the capacity of a single network. On the other hand, a multiple Zigbee network cooperative communication scheme is proposed which jointly build a scalable, high-capacity wireless sensor network. Test results on the CC2530 chip show that the actual capacity of a single Zigbee network can be improved and multiple Zigbee networks can be collaborated with each other. It is verified that the scheme not only improves the Zigbee network’s overall capacity, but also can flexibly expand, increase or delete Zigbee network size and capacity.

Capacity of Cooperative Vehicular Networks With Infrastructure Support: Multiuser Case

Capacity of vehicular networks with infrastructure support is both an interesting and challenging problem as the capacity is determined by the inter-play of multiple factors including vehicle-to-infrastructure (V2I) communications, vehicle-to-vehicle (V2V) communications, density and mobility of vehicles, and cooperation among vehicles and infrastructure. In this paper, we consider a typical delay-tolerant application scenario with a subset of vehicles, termed Vehicles of Interest (VoIs), having download requests. Each VoI downloads a distinct large-size file from the Internet and other vehicles without download requests assist the delivery of the files to the VoIs. A cooperative communication strategy is proposed that explores the combined use of V2I communications, V2V communications, mobility of vehicles and cooperation among vehicles and infrastructure to improve the capacity of vehicular networks. An analytical framework is developed to model the data dissemination process using this strategy, and a closed form expression of the achievable capacity is obtained, which reveals the relationship between the capacity and its major performance-impacting parameters such as inter-infrastructure distance, radio ranges of infrastructure and vehicles, sensing range of vehicles, transmission rates of V2I and V2V communications, vehicular density and proportion of VoIs. Numerical result shows that the proposed cooperative communication strategy significantly boosts the capacity of vehicular networks, especially when the proportion of VoIs is low. Our results provide guidance on the optimum deployment of vehicular network infrastructure and the design of cooperative communication strategy to maximize the capacity.

Experimental assessment of LNC‐based cooperative communication schemes using commercial off‐the‐shelf wireless sensor network nodes

SummaryThe use of wireless sensor network nodes to support reliable communication exposes some challenging issues. For instance, the reduced available bandwidth combined with an error‐prone communication medium impairs the provision of reliable communication services. Network coding techniques can be useful to mitigate some of these issues, where multiple message groups can be combined into single messages and retransmitted to their destinations, improving the network reliability and reducing the bandwidth consumption. However, an effective use of network coding requires the availability of wireless sensor network nodes able to encode/decode messages within the required timing constraints. This paper reports an experimental assessment of commercial off‐the‐shelf wireless sensor network nodes, running a set of network coding encoding/decoding tasks. The assessed nodes range from the high‐performance ARM Cortex‐M7 to the low capability Arduino Uno platforms, including some of the most popular ARM Cortex and ATMEL AVR processors. The performed experimental assessment demonstrates that highly complex network coding techniques (with fields as large as ) can be efficiently implemented on a wide range of wireless sensor network nodes, including ARM Cortex, ATMEL AVR, and Arduino Uno platforms, smoothing some relevant reliable communication implementation issues.

Energy efficiency analysis of differential cooperative algorithm in wireless sensor network

Cooperative MIMO techniques deliver the speed and reliability required for future fifth generation mobile networks. However, coherent MIMO techniques demand high channel estimation complexity as well as high pilot overhead. Hence collaboration of cooperative communication and non-coherent schemes will be particularly beneficial in energy constrained wireless sensor networks (WSNs). Aiming at minimizing the energy consumption per bit, we propose an algorithm for differential cooperative communication in WSNs using unitary space time modulation technique. The algorithm computes the optimum transmission distance for the optimum number of cooperating nodes. The simulation results show that the proposed algorithm provides significant energy saving and increased network lifetime compared with the fixed distance cooperative schemes.