Cooperative Ad-hoc Networks Research Articles

LB-OPAR: Load balanced optimized predictive and adaptive routing for cooperative UAV networks

Cooperative ad-hoc UAV networks have been turning into the primary solution set for situations where establishing a communication infrastructure is not feasible. Search-and-rescue after a disaster and intelligence, surveillance, and reconnaissance (ISR) are two examples where the UAV nodes need to send their collected data cooperatively into a central decision maker unit. Recently proposed SDN-based solutions show incredible performance in managing different aspects of such networks. Alas, the routing problem for the highly dynamic UAV networks has not been addressed adequately. An optimal, reliable, and adaptive routing algorithm compatible with the SDN design and highly dynamic nature of such networks is required to improve the network performance. This paper proposes a load-balanced optimized predictive and adaptive routing (LB-OPAR), an SDN-based routing solution for cooperative UAV networks. LB-OPAR is the extension of our recently published routing algorithm (OPAR) that balances the network load and optimizes the network performance in terms of throughput, success rate, and flow completion time (FCT). We analytically model the routing problem in highly dynamic UAV network and propose a lightweight algorithmic solution to find the optimal solution with O(|E|2) time complexity where |E| is the total number of network links. We exhaustively evaluate the proposed algorithm’s performance using ns-3 network simulator. Results show that LB-OPAR outperforms the benchmark algorithms by 20% in FCT, by 30% in flow success rate on average, and up to 400% in throughput.11DISTRIBUTION STATEMENT A: Approved for Public Release; distribution unlimited AFRL-2021-1606 on 25 May 2021. Other requests shall be referred to AFRL/RIT 525 Brooks Rd Rome, NY 13441.

Development of Relay Selection Method for Audio Transmission in Cooperative Ad Hoc Networks

The quality of service parameters, such as Latency and Bit error rate for audio transmission in IEEE 802.11b Wireless ad hoc network are analyzed in this paper. The issue addressed here is that the quality of the audio, when transmitted directly from source to destination in ad hoc network is low. This can be improved by incorporating a relay between source and destination, where the relay uses decode and forward technique before forwarding the information to the destination. Destination applies Maximal ratio combining (MRC), to combine the signal received from the source and the relay. This concept is called Cooperative communication. A location aware channel estimation based relay selection strategy is proposed in this paper for a wireless ad hoc network. Audio is transmitted using 16 QAM modulation scheme over a Rayleigh fading channel in the presence of additive white Gaussian noise (AWGN). This paper focusses on the relay selection method for audio transmission in cooperative ad hoc networks where best relay is selected based on the average channel strength supported between the source and the destination. Audio quality at the destination is observed for the cases of relay presence and relay absence. Results showed that the measured audio quality with the presence of relay was far better than the measured quality in the absence of relay which stresses the importance of cooperative communication.

Network-Decomposed Hierarchical Cooperation in Ad Hoc Networks With Social Relationships

In this paper, we introduce a network-decomposed hierarchical cooperation (HC) protocol and completely characterize the corresponding throughput--delay trade-off for a large wireless ad hoc network formed in the context of social relationships. Instead of randomly picking source--destination pairings, we first consider a distance-based social formation model characterized by the social group density $\gamma$ and the number of social contacts per node, $q$, where the probability that any two nodes in distance $d$ away from each other are socially connected is assumed to be proportional to $d^{-\gamma}$, which is a feasible scenario. Then, using muiltihop and network-decomposed HC protocols under our social formation model, we analyze a generalized throughput--delay trade-off according to the operating regimes with respect to parameters $\gamma$ and $q$ in both a dense network of unit area and an extended network of unit node density via a non-straightforward network transformation strategy. Our main results reveal that as $\gamma$ increases, performance on the throughput--delay trade-off can remarkably be improved, compared to the network case with no social relationships. It is also shown that in the dense network, the network-decomposed HC protocol always outperforms the multihop protocol, while the superiority of the network-decomposed HC depends on $\gamma$ and the path-loss exponent in the extended network.

Secrecy Capacity Scaling by Jamming-Aided Hierarchical Cooperation in Ad Hoc Networks

The optimal scaling law of secrecy capacity as well as the corresponding achievable scheme have not been fully investigated in ad hoc networks. In this paper, we consider an ad hoc network with eavesdroppers and propose a jamming-aided hierarchical cooperation scheme that achieves the maximum throughput scaling with perfect secrecy in the presence of a given number of eavesdroppers. Our proposed scheme can achieve the linear secrecy capacity scaling in a dense network, while it can achieve the linear or smaller capacity scaling in an extended network, which varies with a path loss exponent. Considering two different networks, which are dense and extended networks, we derive the tolerable intensities of eavesdroppers required for optimal secrecy capacity scaling with our proposed scheme. Our results show that our proposed scheme well achieves optimal secrecy capacity scaling regardless of eavesdroppers' movements. We also reveal that with zero jamming power, our proposed scheme obtains the same scaling law only when the very small number of eavesdroppers exist.

Performance Analysis for Cooperative Ad-hoc Networks in the Presence of Correlated Nakagami Fading

In a cooperative network, the adverse effect of fading is tackled with the assist of intermediate node using spatial diversity. The system model consists of an origin node (O), an intermediate node (I) and a final node (F). In this paper, we derive an end to end symbol error probability (SEP) for the proposed novel max-min switched diversity scheme over a correlated Nakagami-m fading channels. The modulation scheme used in the system model is M-ary Phase Shift Keying (MPSK). The intermediate node utilizes decode and forward (DF) protocol for retransmission. In this system, we assumed that there is a correlation exists between originating-to-intermediate node link and intermediate-to-final node link. The proposed scheme utilizes full channel state information (CSI) therefore offers better performance. The result shows that the proposed scheme performs better than the other competing schemes. It is also found that the correlated channels reduce the end-to-end system performance than the uncorrelated scenario.

Decentralized Opportunistic Spectrum Resources Access Model and Algorithm toward Cooperative Ad-Hoc Networks

Limited communication resources have gradually become a critical factor toward efficiency of decentralized large scale multi-agent coordination when both system scales up and tasks become more complex. In current researches, due to the agent’s limited communication and observational capability, an agent in a decentralized setting can only choose a part of channels to access, but cannot perceive or share global information. Each agent’s cooperative decision is based on the partial observation of the system state, and as such, uncertainty in the communication network is unavoidable. In this situation, it is a major challenge working out cooperative decision-making under uncertainty with only a partial observation of the environment. In this paper, we propose a decentralized approach that allows agents cooperatively search and independently choose channels. The key to our design is to build an up-to-date observation for each agent’s view so that a local decision model is achievable in a large scale team coordination. We simplify the Dec-POMDP model problem, and each agent can jointly work out its communication policy in order to improve its local decision utilities for the choice of communication resources. Finally, we discuss an implicate resource competition game, and show that, there exists an approximate resources access tradeoff balance between agents. Based on this discovery, the tradeoff between real-time decision-making and the efficiency of cooperation using these channels can be well improved.

A link selection strategy for cooperative ad-hoc networks

Cooperative ad-hoc networks are popular because of their ability to provide reliable communication. In this paper, we consider a cooperative ad-hoc network consisting of a source, two decode-and-forward relays and a destination. The source intends to transmit its data to the destination directly as well as through relays. We employ a weighted selection combining at the destination which chooses either the weighted source-to-relay1-to-relay2-to-destination link or source-to-destination link depending upon the instantaneous signal-to-noise-ratio. We derive the end-to-end symbol error probability (SEP) of a triple-hop cooperative network with binary phase-shift keying for a flat, slow Rayleigh fading channel. Further, we develop an algorithm which investigates the performance of this cooperative ad-hoc network in terms of SEP. Results show that the cooperation among the nodes and weighted selection combining improves the performance of ad-hoc networks when compared to a point-to-point link and conventional selection combining.

Selection of Efficient Relay for Energy-Efficient Cooperative Ad Hoc Networks

The Cooperative Communication (CC) is a technology that allows multiple nodes to simultaneously transmit the same data. It can save power and extend transmission coverage. However, prior research work on topology control considers CC only in the aspect of energy saving, not that of coverage extension. This paper identify the challenges in the development of a centralized topology control scheme, named Cooperative Bridges, which reduces transmission power of nodes as well as increases network connectivity. Previous research on topology control with CC only focuses on maintaining the network connectivity, minimizing the transmission power of each node, whereas ignores the energy efficiency of paths in constructed topologies. This may cause inefficient routes and hurt the overall network performance in cooperative ad hoc networks. With the help of studied topology control problem for energy-efficient topology with cooperative communication. This paper proposed optimum relay nodes selection for CC network to reduce overall power consumption of network.

PRP: A primary replacement protocol based on early discovery of battery power failure in MANETs

In cooperative Mobile Ad-hoc Networks (MANETs), copies of data are replicated on different mobile devices to improve system's availability. A primary or authoritative control node is assigned to act as a coordinator for the shared data copies, when this primary fails, another node has to be elected to replace the failed one. Since mobile devices have a limited battery power, the primary may fail at any time. Moreover, current primary election protocols in MANETs employ a notable wireless communication overhead which consumes a considerable amount of battery power. In this paper, we propose a novel protocol, called Primary Replacement Protocol (PRP), to replace an exhausted primary in MANETs based on the measurement of its remaining battery power early before it dies. More specifically, PRP replaces the exhausted primary with a healthy node when its remaining battery power reaches a predefined threshold. This replacement can be accomplished with much less communication overhead. Hence, our approach has two contributions: 1) reducing the chance of primary outage by early detection of potential power failure, 2) saving the power that is consumed in traditional primary election approaches due to communication overhead.

COOPERATIVE AD-HOC NETWORKS FOR ENERGY EFFICIENT IMPROVE CONNECTIVITY

Mobile ad-hoc network (MANET) has been developed to meet the increase in demand for high-speed wireless network. Wireless adhoc networks are multi-hop frameworks comprising of connections among wireless nodes in the absence of any infrastructure. Thus they normally consist of unpredicted network topologies. In MANETs nodes have the liberty to move freely in various directions. Due to limited battery power, nodes require energy efficient routing protocols to gear up their network performance. Cooperative communication plays an important role in wireless networks. This is evident from the fact that most of the present cooperative communication works are aimed at link-level physical layer issues. As a consequence, the influence of cooperative communication on network-level upper layer issues, such as topology control, routing and network capacity is unnoticed. Cooperative communication is a technology by the help of which multiple nodes transmit similar data at the same time. This increases the transmission coverage and also saves power. Earlier research work on topology control dealt with cooperative communication in the form of energy saving only and did not consider for extending the coverage. It has been noticed that cooperative communication can link disconnected networks. To overcome this problem, we have studied energy efficient topology control with cooperative communication. In this paper, it has been proposed for selection of optimum relay nodes so as to decrease the overall power consumption in the cooperative ad-hoc network.

A Noise-Correlated Cancellation Transmission Scheme for Cooperative MIMO Ad Hoc Networks

A new transmission scheme based on noise-correlated cancellation (NCC) is proposed, which absorbs the advantages of phase-inversion symmetric method and cooperative MIMO technology and makes full use of the correlation of noise in the adjacent channels to reduce channel noise. This paper firstly presents the implementation process of NCC transmission scheme in detail. Further, through theoretical analysis, it is showed that the signal-to-noise ratio gain which the proposed NCC transmission scheme gets is at least 4 times greater than the signal-to-noise ratio gain which the traditional cooperative MIMO transmission scheme gets. Finally, simulation experiment results also verify that the proposed NCC transmission scheme can make the channel capacity per bandwidth of cooperative MIMO Ad Hoc networks improve significantly and bit error rate (BER) of the network reduce greatly, which will help to expand application scopes of cooperative MIMO Ad Hoc networks.

Dynamic cooperative clustering based power assignment: network capacity and lifetime efficient topology control in cooperative ad hoc networks.

Cooperative communication (CC) is used in topology control as it can reduce the transmission power and expand the transmission range. However, all previous research on topology control under the CC model focused on maintaining network connectivity and minimizing the total energy consumption, which would lead to low network capacity, transmission interruption, or even network paralysis. Meanwhile, without considering the balance of energy consumption in the network, it would reduce the network lifetime and greatly affect the network performance. This paper tries to solve the above problems existing in the research on topology control under the CC model by proposing a power assignment (DCCPA) algorithm based on dynamic cooperative clustering in cooperative ad hoc networks. The new algorithm clusters the network to maximize network capacity and makes the clusters communicate with each other by CC. To reduce the number of redundant links between clusters, we design a static clustering method by using Kruskal algorithm. To maximize the network lifetime, we also propose a cluster head rotating method which can reach a good tradeoff between residual energy and distance for the cluster head reselection. Experimental results show that DCCPA can improve 80% network capacity with Cooperative Bridges algorithm; meanwhile, it can improve 20% network lifetime.

Relay Management in Energy-aware Cooperative Ad Hoc Networks: A Perspective of Stochastic Game

Relay Management in Energy-aware Cooperative Ad Hoc Networks: A Perspective of Stochastic Game

Modeling Mobility in Cooperative Ad Hoc Networks

This paper addresses issues concerned with design and managing of mobile ad hoc networks. We focus on self-organizing, cooperative and coherent networks that enable a continuous communication with a central decision unit and adopt to changes in an unknown environment to achieve a given goal. In general, it is very difficult to model a motion of nodes of a real-life ad hoc network. However, mobility modeling is a critical element that has great influence on the performance characteristics of a cooperative system. In this paper we investigate a novel approach to cooperative and fully connected networks design. We present an algorithm for efficient calculating of motion trajectories of wireless devices. Our computing scheme adopts two techniques, the concept of an artificial potential field and the concept of a particle-based mobility. The utility and efficiency of the proposed approach has been justified through simulation experiments. The results of presented case studies show a wide range of applications of our method starting from simple to more complex ad hoc networks.

Outage Analysis of Opportunistic Cooperative Ad Hoc Networks with Randomly Located Nodes

In this paper, an opportunistic cooperative ad hoc sensor network with randomly located nodes is analyzed. The randomness of nodes’ locations is captured by a homogeneous Poisson point process. The effect of imperfect interference cancellation is also taken into account in the analysis. Based on the theory of stochastic geometry, outage probability and cooperative gain are derived. It is demonstrated that explicit performance gain can be achieved through cooperation. The analyses are corroborated by extensive simulation results and the analytical results can thus serve as a guideline for wireless sensor network design.

Energy-Efficient Topology Control in Cooperative Ad Hoc Networks

Cooperative communication (CC) exploits space diversity through allowing multiple nodes cooperatively relay signals to the receiver so that the combined signal at the receiver can be correctly decoded. Since CC can reduce the transmission power and extend the transmission coverage, it has been considered in topology control protocols [1], [2]. However, prior research on topology control with CC only focuses on maintaining the network connectivity, minimizing the transmission power of each node, whereas ignores the energy efficiency of paths in constructed topologies. This may cause inefficient routes and hurt the overall network performance in cooperative ad hoc networks. In this paper, to address this problem, we introduce a new topology control problem: energy-efficient topology control problem with cooperative communication, and propose two topology control algorithms to build cooperative energy spanners in which the energy efficiency of individual paths are guaranteed. Both proposed algorithms can be performed in distributed and localized fashion while maintaining the globally efficient paths. Simulation results confirm the nice performance of all proposed algorithms.

Secure Incentive Algorithm Based on Strategy-Proof Payment Model for Cooperation in Ad Hoc Networks

Cooperation among nodes is important in Ad Hoc networks since in such networks nodes depend on each other for forwarding packets.However,cooperation in such operations consumes nodes energy and recourses.Therefore,it is necessary to design incentive mechanisms to improve the enthusiasm of cooperation among nodes.In this paper,we analyze the Ad Hoc-VCG model based on algorithmic mechanism design,point out its main problems,propose a strategy-proof and collusion-resistant payment model and design an algorithm called ICTP(Incentive Cooperative sTrategy-proof Payment algorithm),which consists of two procedures: routing establishment and data packets forwarding.At last,we verify the effectiveness and correctness of this algorithm by simulation using NS2,compare its performance with other classical algorithms: Ad Hoc-VCG,COMMIT and LMOCP.Simulation results show that ICTP performs better than other algorithms.

An Optimal Algorithm for Relay Node Assignment in Cooperative Ad Hoc Networks

Recently, cooperative communications, in the form of having each node equipped with a single antenna and exploit spatial diversity via some relay node's antenna, is shown to be a promising approach to increase data rates in wireless networks. Under this communication paradigm, the choice of a relay node (among a set of available relay nodes) is critical in the overall network performance. In this paper, we study the relay node assignment problem in a cooperative ad hoc network environment, where multiple source-destination pairs compete for the same pool of relay nodes in the network. Our objective is to assign the available relay nodes to different source-destination pairs so as to maximize the minimum data rate among all pairs. The main contribution of this paper is the development of an optimal polynomial time algorithm, called ORA, that achieves this objective. A novel idea in this algorithm is a “linear marking” mechanism, which maintains linear complexity of each iteration. We give a formal proof of optimality for ORA and use numerical results to demonstrate its capability.

Enabling Cooperative Ad Hoc Networks under Noise

Enabling Cooperative Ad Hoc Networks under Noise

Fairness improves throughput in energy-constrained cooperative Ad-Hoc networks

In ad-hoc networks, cooperative diversity is especially beneficial where the use of multiple antennas may be impractical. There has been a lot of work on improving the peer-to-peer link quality by using advanced coding or power and rate allocation between a single source node and its relays. However, how to fairly and efficiently allocate resources among multiple users and their relays is still unknown. In this paper, a multiuser cooperative protocol is proposed, where a power reward is adopted by each node to evaluate the power contributed to and by others. It will be shown that the proposed fair cooperative protocol (FAP) can significantly improve the fairness performance compared to full cooperation. It is further demonstrated that in energy-constrained cooperative ad-hoc networks, fairness can actually bring significant throughput gains. The tradeoff between fairness and throughput is analyzed and two price-aware protocols, FAP-R and FAP-S, will be further proposed to improve fairness. Simulation results will validate our analysis and show that compared to the direct transmission (i.e., without cooperation) and the full cooperation, our proposed FAP, FAP-R and FAP-S can achieve much better fairness performance along with substantial throughput gains.