Multi-hop Cooperative Transmission Research Articles

Secrecy Performance Analysis of Cooperative Multihop Transmission for WSNs under Eavesdropping Attacks.

Multihop transmission is one of the important techniques to overcome the transmission coverage of each node in wireless sensor networks (WSNs). However, multihop transmission has a security issue due to the nature of a wireless medium. Additionally, the eavesdropper also attempts to interrupt the legitimate users' transmission. Thus, in this paper, we study the secrecy performance of a multihop transmission under various eavesdropping attacks for WSNs. To improve the secrecy performance, we propose two node selection schemes in each cluster, namely, minimum node selection (MNS) and optimal node selection (ONS) schemes. To exploit the impact of the network parameters on the secrecy performance, we derive the closed-form expression of the secrecy outage probability (SOP) under different eavesdropping attacks. From the numerical results, the ONS scheme shows the most robust secrecy performance compared with the other schemes. However, the ONS scheme requires a lot of channel information to select the node in each cluster and transmit information. On the other side, the MNS scheme can reduce the amount of channel information compared with the ONS scheme, while the MNS scheme still provides secure transmission. In addition, the impact of the network parameters on the secrecy performance is also insightfully discussed in this paper. Moreover, we evaluate the trade-off of the proposed schemes between secrecy performance and computational complexity.

Optimal Relay Selection Strategy for Efficient and Reliable Cluster-Based Cooperative Multi-Hop Transmission in Vehicular Communication

Routing is the key issue for Vehicular Networks since each node in the network has mobility. The dynamic nature of vehicular networks increases with mobility and the consequence is reflected in controlling traffic overhead. As a result, the routing technique and the type of node mobility information are completely dependent on building dependable end-to-end communication links. To address these challenges, a Reliable Cluster-based Multi-Hop Cooperative Routing (RCCR) strategy was proposed by using velocity, distance, and link quality parameters. This algorithm obtains the tradeoff between Quality of Service (QoS) and mobility constraints over link parameters. It improves routing scalability by electing cluster heads and selecting Multi-Point Relays (MPRs) while considering mobility constraints and QoS needs. The proposed technique determines the link quality for every pair of nodes based on values of signal strength and distance parameters. The relay vehicles are chosen based on the highest possible QoS value, which is calculated to assure route stability, reliability, and durability. The heuristic limitations of the multi-point relay selection strategy are handled by considering the link quality, distance from the source vehicle, and cluster-head coverage area to enhance the performance of the multi-hop network with tolerable End-to-End transmission delay. Further, we obtained an optimal number of cooperative vehicles in every hop. Finally, simulation results demonstrate the effectiveness of the proposed algorithm compared to other state of art algorithms.

Energy Efficient Multi-hop Cooperative Transmission Protocol for Large Scale Mobile Ad hoc Networks

Energy Efficient Multi-hop Cooperative Transmission Protocol for Large Scale Mobile Ad hoc Networks

Adaptive cooperative routing transmission for energy heterogeneous wireless sensor networks

The mass machine type communication (mMTC) in 5G requires the technical support of the wireless sensor network (WSN). Compared with homogeneous WSNs, heterogeneous WSNs provide more flexibility and are more in line with the reality. For heterogeneous WSNs, the use of proper routing methods can prolong the lifetime as well as the stability of the system. This paper studies an energy heterogeneous WSN, where nodes can cooperate with each other to improve the energy efficient of the network. We focus on the network routing within distributed energy-efficient clustering (DEEC) protocol, a typical networking/communication protocol for heterogeneous WSNs. First, we derive a proposition on the choice of cooperative single-hop or multi-hop modes, which gives a sufficient condition on cooperative multi-hop transmission. Furthermore, we present two lemmas, which are the conditions on the distance threshold for mode selection. Based on the above, a novel adaptive cooperative routing algorithm combined with DEEC is proposed. Simulation results show that the proposed routing algorithm outperforms the benchmark schemes and can effectively reduce the network energy consumption and prolong the network lifetime.

Secrecy Performance Enhancement for Underlay Cognitive Radio Networks Employing Cooperative Multi-Hop Transmission with and without Presence of Hardware Impairments.

In this paper, we consider a cooperative multi-hop secured transmission protocol to underlay cognitive radio networks. In the proposed protocol, a secondary source attempts to transmit its data to a secondary destination with the assistance of multiple secondary relays. In addition, there exists a secondary eavesdropper who tries to overhear the source data. Under a maximum interference level required by a primary user, the secondary source and relay nodes must adjust their transmit power. We first formulate effective signal-to-interference-plus-noise ratio (SINR) as well as secrecy capacity under the constraints of the maximum transmit power, the interference threshold and the hardware impairment level. Furthermore, when the hardware impairment level is relaxed, we derive exact and asymptotic expressions of end-to-end secrecy outage probability over Rayleigh fading channels by using the recursive method. The derived expressions were verified by simulations, in which the proposed scheme outperformed the conventional multi-hop direct transmission protocol.

A Cooperative Multihop Transmission Scheme for Two-Way Amplify-and-Forward Relay Networks

In this paper, we present a cooperative multihop transmission scheme for two-way amplify-and-forward (AF) relay networks. Based on a symbol error probability (SEP) analysis and using geographic information, we derive the maximum one-hop distance for a networking node under a given SEP and develop a next-hopping-node selection scheme. With these results, we then propose a routing protocol based on a greedy algorithm to realize the transmission scheme, where a routing path consisting of a number of independent two-way AF relaying procedures is built to connect the two sources. As compared to a previous related work, the proposed approach removes the utilization limitation and improves the routing efficiency. Computer simulation results also show that it provides a higher probability of successfully building a routing path with close effective throughput for most cases of interest.

A Study of Multi-Hop Wireless Networks Model for Smart Vehicle Adaptive Traffic

The expanding ring search is a useful technique for reducing the overhead of the broadcast storm problem when it is applied to route-searching in multi-hop wireless network for adaptive trajectory service. Usually the centered source in this algorithm searches successively larger areas to find out the vehicle location information for trajectory service and wireless network traffic condition. In this paper we propose an expanding ring search with multi-hop cooperative transmission and routing strategies that can be applied to the second part of Cognitive-Adaptive-A-Software (CAAS) Project. We suggest that the proposed scheme should be applied to Multi-hop Wireless Network Model for Smart Vehicle Adaptive Traffic.

레일리 페이딩 채널을 통해 결합된 등가 이득 협력 라우팅의 에너지 효율

In this paper, we propose a multi-hop cooperative transmission protocol to obtain energy savings in static wireless networks. Each terminal in the network is equipped with a single antenna and each receiver uses equal gain combining technique (EGC) to combine received signals. We also propose a power allocation strategy which optimizes the total transmit power at each stage. Monte-Carlo simulations are presented to evaluate and compare performance of the proposed protocol with the multi-hop direct transmission (MDT) and the cooperative routing protocol proposed by Khadani [8], in terms of the average total transmit power and the average number of required stages.

모바일 애드혹 무선 네트워크에서 멀티 홉 협력 전송 프로토콜

In this paper, we propose a multi-hop cooperative transmission protocol over Rayleigh fading channels. In the proposed protocol, the multi-hop cooperative transmission is used to improve the system performance. Due to broadcast nature, we do not limit the receiving node to be only the next node, but the destination and all the nodes between the transmitting node and the destination. The proposed protocol can hence save the average transmit power, compared with multi-hop direct transmission protocol due to the skipped transmissions from some intermediate nodes or chosen relays. The proposed scheme is implemented and evaluated in mobile ad-hoc wireless networks.

Multi-hop transmission and routing with hierarchical modulation

Hierarchical modulation multiplexes layers of different robustness into one stream. Usually being exploited in broadcast systems such as digital video broadcasting, hierarchical modulation can also be applied to unicast communications in a cooperative manner. This article deals with novel multi-hop cooperative transmission and routing strategies with hierarchical modulation. In multi-hop networks, when intermediate nodes receive different sets of streams, they cooperatively forward streams toward the final destination. We first show how hierarchical modulation reduces the total number of transmissions in tandem networks. We then model an optimization problem that determines proper modulation schemes and routing strategies as a stationary infinite-horizon Markov decision process (MDP). The MDP problem requires exponential computations forcing us to delve for heuristic solutions. We simplify the optimization problem by restricting hierarchical modulation consisting of only two fixed constellations. Even with this approximation, the routing problem with hierarchical modulation is still too complex because we must consider all possible paths and hierarchical modulation schemes at the same time. We introduce an approximation scheme that determines the most efficient hierarchical modulation scheme for each three node subgraph assuming subgraphs are isolated each other. Based on the three node subgraph approximation, we map original graphs to virtual graphs. We then apply one of shortest path algorithm to the virtual graphs to find the best route with hierarchical modulation. We perform simulations with various network topologies to evaluate the efficiency of hierarchical modulation in multi-hop unicast communication. Our results show that hierarchical modulation enhances the throughput about 25–30% compared to non-hierarchical modulation. However, optimal solution derived by solving the MDP is also 5% better than heuristic solutions suggesting the necessity to develop better heuristics in future.

Cooperative Multi-Hop Transmission Protocol with Incremental Relaying Strategy over Rayleigh Fading Channel

In this paper, we propose a novel protocol called Cooperative Multi-hop transmission using Incremental Relaying (CMIR). We evaluate the performance of the CMIR protocol by deriving expressions for the average end-to-end outage probability and the average number of transmissions. Monte Carlo simulations are presented to verify the accuracy of the theoretical analyses.

Multi-hop cooperative transmission using fountain codes over Rayleigh fading channels

In this paper, we study multi-hop cooperative transmission protocols using fountain codes. The proposed protocols can reduce the end-to-end delay and number of stages compared to those in conventional multi-hop transmission. Various Monte-Carlo simulations are presented to evaluate and compare performance of the protocols over Rayeigh fading channels.

A Quasi-Stationary Markov Chain Model of a Cooperative Multi-Hop Linear Network

We consider a quasi-stationary Markov chain as a model for a decode and forward wireless multi-hop cooperative transmission system that forms successive Opportunistic Large Arrays (OLAs). This paper treats a linear network topology, where the nodes form a one-dimensional horizontal grid with equal spacing. In this OLA approach, all nodes are intended to decode and relay. Therefore, the method has potential application as a high-reliability and low-latency approach for broadcasting in a line-shaped network, or unicasting along a pre-designated route. We derive the transition probability matrix of the Markov chain based on the hypoexponential distribution of the received power at a given time instant assuming that all the nodes have equal transmit power and the channel has Rayleigh fading and path loss with an arbitrary exponent. The state is represented as a ternary word, which indicates which nodes have decoded in the present hop, in a previous hop, or have not yet decoded. The Perron-Frobenius eigenvalue and the corresponding eigenvector of the sub-stochastic matrix indicates the signal-to-noise ratio (SNR) margin that enables a given hop distance.

Energy aware power allocation strategies for multihop-cooperative transmission schemes

This paper is focused on the optimization of transmitted power in a cooperative decoded relaying scheme for nodes belonging to the single primary route towards. a destination. The proposed transmission protocol, referred to as Multihop Cooperative Transmission Chain (MCTC), is based on the linear combination of copies of the same message by multiple previous terminals along the route in order to maximize the multihop diversity. Power allocations among transmitting nodes in the route can be obtained according to the average (not instantaneous) node-to-node path attenuation using a recursive power assignment. The latter can be employed locally on each node with limited signalling exchange (for fixed or nomadic terminals) among nodes. In this paper the power assignments for the MCTC strategy employing conventional linear combining schemes at receivers (i.e., selection combining, maximal ratio combining and equal gain combining) have been derived analytically when the power optimization is constrained to guarantee the end-to-end outage probability. In particular, we show that the power assignment that minimize the maximum spread of received power (min-max strategy) can efficiently exploit the multihop diversity. In addition, for ad hoc networks where the energy of each node is an issue, the MCTC protocol with the min-max power assignment increases considerably the network lifetime when compared to non-cooperative multihop schemes

Cooperative multi-hop transmission in wireless networks

We consider various relaying strategies for wireless networks by comparatively examining direct transmission, conventional relaying, and the novel concepts of cooperative relaying. The latter build...

Cooperative multi-hop transmission in wireless networks

We consider various relaying strategies for wireless networks by comparatively examining direct transmission, conventional relaying, and the novel concepts of cooperative relaying. The latter build on two inherent benefits of relaying systems: the spatial diversity offered by the relay channel, and the ability to exploit the broadcast nature of the wireless medium. Studied cooperative protocols include adaptive decode-and-forward schemes as a simple extension of conventional store-and-forward relaying systems, and more complex decode-and-reencoding schemes that realize distributed coding strategies. We provide a unifying analysis for the tractable two-hop case, before extending the consideration to multi-hop scenarios. The analysis is conducted from the perspective of communication over fading channels under limited bandwidth, energy, and end-to-end delay; main parameters include propagation loss, network geometry, and targeted end-to-end spectral efficiency. Main results indicate that (i) cooperative relaying provides attractive benefits for wireless systems whenever temporal and frequency diversity are scarce or not exploited, (ii) using just two hops is reasonable for many practical scenarios, and (iii) the advantages of the studied relaying schemes decrease for higher desired end-to-end spectral efficiency.