Multi-Radio Cooperation Technology and Heterogeneous Network Convergence

The heterogeneous network convergence is the trend of future network development. However, many bottlenecks exist in the converged system such as high time delay, high energy consumption, and low data rate. Multi-Radio Cooperation (MRC) technology is specially designed to overcome these bottlenecks and to satisfy the requirements of heterogeneous network convergence. MRC can improve network capacity, reduce the energy consumption of radio devices, and decrease handover latency between heterogeneous networks by the cooperation of multiple radios, and by efficient management and feasible allocation of multi-radio resources. MRC makes real seamless heterogeneous network convergence possible.

Mesh-Based Network Convergence and Cooperation

More and more distinctive heterogeneous features are exhibited in wireless networks in multitude of networks, technologies, terminals, operation and management, and more. Effective convergence and cooperation of heterogeneous networks can be achieved through Mesh technology. The IP-based convergence integrates common features of heterogeneous networks, while the cooperation coordinates personalities of the networks. By using the convergence and cooperation, a standardized integration of separated and localized predominant capabilities and resources of heterogeneous networks can be fulfilled to enable the evolution into an ubiquitous and omnipotent intelligent network.

Cooperative Relay Networks Based on the OAM Technique for 5G Applications

Orbital Angular Momentum(OAM)is an intrinsic property of electro-magnetic waves.Great research has been witnessed in the last decades aiming at exploiting the OAM wave property in different areas in radio and optics.One pro-mising area of particular interest is to enhance the efficiency of the available communications spectrum.However,adopting OAM-based solutions is not priceless as these suffer from wave divergence especially when the OAM order is high.This shall limit the practical communications distance,especially in the radio regime.In this paper,we propose a cooperative OAM relaying system consisting of a source,relay,and destination.Relays help the source to transmit packets to the destination by providing an alternative connection between source and desti-nation.This cooperative solution aims on the one hand,through best-path selection,on increasing the communications range.On the other hand,through the parallel transmission orders allowed by OAM carrying waves,the system could raise its total transmission throughput.Simulation results show that combining a cooperative relay with OAM improves the system throughput compared to using each element separately.In addition,the proposed cooperative relaying OAM out-performs the cooperative relaying non-orthogonal multiple access scheme,which is a key spectrally efficient technique used in 5G technology.

Evolution Characteristics of Government-Industry-University-Research Cooperative Innovation Network for China＇s Agriculture and Influ- encing Factors： Illustrated According to Agricultural Patent Case

Under the special background of China, the cooperative innovation between different government-industry-university-research institutes plays an increasingly important role in the agricultural field. However, the existing literature has paid little attention to it. Considering the cooperation patents, published in the agriculture field stemming from the Full-text Database of China Patents as the study object, the spatial and institutional attribute of the authors as the data source, and by combining the social network and spatial econometrics analysis, this paper analyzes the structure evolution characteristics of cooperative innovation networks of agricultural government-industry-university-research institute in the city level of China in 1985–2014, based on the triple helix theory, with the influence factors discussed. This shows that, 1) since 1985, China's agricultural innovation level has been substantially increased, but the development degree of the cooperative innovation network is low, and the patent cooperation mainly relies on authors in the same unit; 2) enterprises play a leading role in the agricultural cooperative innovation. The effect of the government and hybrid organizations driven by the government is not obvious; 3) the cooperative innovation in the province and city dominates, and a multi-pole pattern has been formed. The cooperative innovation network structure evolves from a single helix empty core and double helix multi core to a double helix hierarchical network; 4) the city's science, education funding and personnel investment are key factors determining the agricultural cooperative innovation, while the agricultural development of the city presents slight negative impacts on it. The spatial mismatch of supply and demand is present in the technical cooperative innovation of China's agriculture. Therefore, the science enhancement and education investment to big agricultural provinces should be promptly implemented.

Structure of Chinese City Network as Driven by Technological Knowledge Flows

Based on patent cooperation data,this study used a range of city network analysis approaches in order to explore the structure of the Chinese city network which is driven by technological knowledge flows.The results revealed the spatial structure,composition structure,hierarchical structure,group structure,and control structure of Chinese city network,as well as its dynamic factors.The major findings are:1) the spatial pattern presents a diamond structure,in which Wuhan is the central city;2) although the invention patent knowledge network is the main part of the broader inter-city innovative cooperation network,it is weaker than the utility model patent;3) as the senior level cities,Beijing,Shanghai and the cities in the Zhujiang(Pearl) River Delta Region show a strong capability of both spreading and controlling technological knowledge;4) whilst a national technology alliance has preliminarily formed,regional alliances have not been adequately established;5) even though the cooperation level amongst weak connection cities is not high,such cities still play an important role in the network as a result of their location within ′structural holes′ in the network;and 6) the major driving forces facilitating inter-city technological cooperation are geographical proximity,hierarchical proximity and technological proximity.

Relay-Assisted Cooperative Communication Networks

To facilitate the demand for a higher spectrum and power efficiency arising from the next generation mobile communication system, the introduction of relay-aided cooperative communication into the existing cellular infrastructure is considered as the most practical improvement under high rate and coverage. In comparison with the legacy cellular network, relay-aided cooperative communication network enjoys relative advantages over coverage efficiency, operation cost and transmission capacity. Transmission in relay-aided cooperative system falls into three types: the three-terminal transmission model, two-hop multi-relay parallel transmission model, and multi-hop multi-relay transmission model. For the extensive perspective of relay-aided cooperative communication in application, a profound research has been carried out in communication standards such as Worldwide Interoperability for Microwave Access (WiMAX) and Wireless World Initiative New Radio (WINNER).

Compressed Sensing-Based Multiuser Cooperative Networks

To avoid interference, compressed sensing is introduced into multiuser cooperative network. A cooperative compressed sensing and amplify-and-forward(CCS-AF)scheme is proposed, and it is proved that the channel capacity increases compared with the traditional cooperative scheme by considering the CCS-AF transmission matrix as the measurement matrix. Moreover, a new power allocation algorithm among the relays is proposed to improve the channel capacity. Numerical results validate the effectiveness of the proposed scheme.

Traffic Allocation Scheme with Cooperation of Multiple RANs in Universal Wireless Environments

This paper introduces an adaptive traffic allocation scheme with cooperation of multiple Radio Access Networks (RANs) in universal wireless environments.The different cooperation scenarios are studied,and based on the scenario of cooperation in both network layer and terminal layer,an open queuing system model,which is aiming to depict the characteristics of packet loss rate of wireless communication networks,is proposed to optimize the traffic allocation results.The analysis and numerical simulations indicate that the proposed scheme achieves inter-networking load balance tominimize the whole transmission delay and expands the communication ability of single-mode terminals to support high data rate traffics.

Wireless Mesh Networks and Cooperative Relaying Technologies

The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it cannot be applied in situations where large coverage is required . The use of cooperative relaying technologies can improve the transmission rate and reliability of wireless link; while the wireless Mesh network, once integrated with cooperative relaying technologies and routing technologies , can improve its spectrum efficiency and cover a wide area . However, there are many problems to be solved with respect to standardization, key technologies research and industrialization. Therefore , the application of cooperative relaying technologies in wireless Mesh networks is still a great challenge .

Cooperative wireless networks for better green services

In order to guarantee the overall return on investment (ROI), improve user experience and quality of service (QoS), save energy, reduce electra magnetic interference (EMI) and radiation pollution, and enable the sustainable deployment of new profitable applications and services in heterogeneous wireless networks coexistence reality, this paper proposes a cross-network cooperation mechanism to effectively share network resources and infrastructures, and then adaptively control and match multi-network energy distribution characteristics according to actual user/service requirements in different geographic areas. Some idle or lightly-loaded base stations (BS or BSs) will be temporally turned off for saving energy and reducing EMI. Initial simulation results show that the proposed approach can significantly improve the overall energy efficiency and QoS performance across multiple cooperative wireless networks.

Wireless Cooperative Mesh Network:A New Architecture for Network Convergence

The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging problems in convergence as transmission mode selection,load balancing,routing and handover.The new architecture is based on the structure of Wireless Mesh Networks(WMNs),and cooperative communication is also employed to further optimize its structure and upgrade its performance.It can thus obtain advantages of both the Mesh technology(high spectrum efficiency and dynamic self-organization) and cooperative communication(high diversity gain and high energy efficiency).The new architecture serves as an efficient solution for wireless network convergence.

Performance Analysis of Mixed Amplify-and-Forward and Decode-and-Forward Protocol in Underlay Cognitive Networks

In this paper, we propose and evaluate outage performance of a mixed amplify-and-forward(AF) and decode-and-forward(DF) relaying protocol in underlay cognitive radio. Different from the conventional AF and DF protocols, in the proposed protocol, a secondary source attempts to transmit its signal to a secondary destination with help of two secondary relays. One secondary relay always operates in AF mode, while the remaining one always operates in DF mode. Moreover, we also propose a relay selection method, which relies on the decoding status at the DF relay. For performance evaluation and comparison, we derive the exact and approximate closedform expressions of the outage probability for the proposed protocol over Rayleigh fading channel. Finally, we run Monte Carlo simulations to verify the derivations. Results presented that the proposed protocol obtains a diversity order of three and the outage performance of our scheme is between that of the conventional underlay DF protocol and that of the conventional underlay AF protocol.

Practical Polar Code Construction For Degraded Multiple-Relay Networks

In this paper, based on the characteristics of polar codes, a new decode-and-forward strategy called generalized partial information relaying protocol is proposed for degraded multiple-relay networks with orthogonal receiver components(MRNORCs). In such a protocol, with the help of partial information from previous nodes, each relay node tries to recover the received source message and re-encodes part of the decoded message for transmission to satisfy the decoding requirements for the following relay node or the destination node. In order to construct practical polar codes, the nested structures are developed based on this protocol and the information sets corresponding to the partial messages forwarded are also calculated. The proposed scheme is proved to be capable of achieving the theoretical capacity of the degraded MRN-ORCs while still retains the low-complexity feature of polar codes. We perform simulations to testify the practicability of the proposed scheme and compare polar codes by using successive-cancellation list decoder(SCLD) with traditional low-density parity-check(LDPC) codes. The results show that the obtained polar codes provide significant gain.

Relaying Strategy Based on Estimated Information for Multi-Antenna Cooperative Networks

A sphere-based list forwarding scheme for multiple-input multiple-output(MIMO) relay networks is proposed and analyzed. Firstly, an estimate forwarding(EF) method is proposed, which forwards the minimum mean squared error(MMSE) estimate of the source data to the destination. Since it performs like amplify-and-forward(AF) and decode-and-forward(DF) for the low and high signal-to-noise ratio(SNR) regions, respectively, the EF relay thus outperforms conventional AF and DF across all SNRs without the need for switching algorithms for different SNRs. Because computational complexity is however high for relays with a large number of antennas(large MIMO) and/or high order constellations, list EF for large MIMO relay networks is proposed. It computes a list sphere decoder based MMSE estimate and retains the advantages of the exact EF relay at a negligible performance loss. The proposed list EF could offer a flexible trade-off between the performance and computational complexity.

Degree-Based Probabilistic Caching in Content-Centric Networking

Content-Centric Networking is a novel future network architecture that attracts increasing research interests in recent years. In-network caching has been regarded as a prominent feature of Content-Centric Networking since it is able to reduce the network traffic, alleviate the server bottleneck and decrease the user access latency. However, the CCN default caching scheme results in a high caching redundancy, causing an urgent need for an efficient caching scheme. To address this issue, we propose a novel implicit cooperative caching scheme to efficiently reduce the caching redundancy and improve the cache resources utilization. The simulation results show that our design achieves a higher hit ratio and a shorter cache hit distance in comparison with the other typical caching schemes.

Dual-threshold symbol selective relaying in cooperative networks

In order to efficiently mitigate error propagation and reduce computational complexity, this paper proposes a scheme for traditional cooperative networks, named as dual-threshold symbol selective demodulate-and-forward. In the scheme, two log likelihood ratio(LLR)-based thresholds are devised to measure the reliability of received signals for the relay and the destination, respectively. One of the threshold guarantees that the relay only forwards reliable symbols, thus less error will be propagated to the destination. The other threshold is used at the destination for determining the reliability of symbols received from the source.The destination will directly demodulate reliable symbols received from the source. Otherwise, when the symbols received from the source are not reliable, the maximum ratio combiner(MRC) is used to combine symbols received from the source and the relay.Closed-form expression of the bit error probability(BEP) of the proposed scheme is derived and analyzed under binary phase shift keying(BPSK) modulation. Then, the relationship and closed-form solutions of two LLR-based thresholds are derived. Simulation results prove that the theoretical BEP of the proposed scheme closely matches the simulated ones. The proposed scheme can achieve high performance with low computational complexity compared to existing schemes.

Secrecy-Enhancing Design for Two-Way Energy Harvesting Cooperative Networks with Full-Duplex Relay Jamming

To guarantee secure information transmission within two sources,a full-duplex(FD)relay jamming scheme for two-way energy harvesting(EH)cooperative networks is proposed,in which the relay can achieve simultaneous information reception and jamming transmission.The EH relay node scavenges energy from two source signals,and then,uses the harvested energy for information relaying and jamming transmission by the power splitting(PS)protocol.Considering multiple eavesdroppers,the nonconvex optimization for maximizing the smaller bidirectional secrecy rates is formulated by jointly optimizing the power allocation and PS factor.Furthermore,an iterative algorithm based on successive convex approximation and alternate search method is proposed to solve this non-convexity.Simulation results verify the proposed iterative algorithm and show that the proposed jamming scheme can achieve substantial performance gain than other conventional schemes.

Energy-Efficient Jammer Selection Approach for QoS Provisioning in Distributed Wireless Cooperative Networks

Abstract：Aiming at achieving better Quality of Service （QoS） provisioning in distributed wireless cooperative networks, a novel energy efficient jammer selection approach is proposed in this pa per. We employ Secrecy Capacity （SC） to charac terize the security of transmission. In order to ac curately describe the timevarying characteristic, related channels are modeled as FiniteState M ark ov Channels （FSMCs）. The remaining energy of candidate node is considered in a similar way.

A Beamforming Technique Using Rotman Lens Antenna for Wireless Relay Networks

Rotman lens,which is a radio frequency beam-former that consists of multiple input and multiple output beam ports,can be used in industrial,scientific,and medical applications as a beam steering device.The input ports collect the signals to be propagated through the lens cavity toward the output ports before being transmitted by the antenna arrays to the destination in order to enhance the error performance by optimizing the overall signal to noise ratio(SNR).In this article,a low-cost Rotman lens antenna is designed and deployed to enhance the overall performance of the conventional cooperative communication systems without needing any additional power,extra time or frequency slots.In the suggested system,the smart Rotman lens antennas generate a beam steering in the direction of the destination to maximize the received SNR at the destination by applying the proposed optimal beamforming technique.The suggested optimal beamforming technique enjoys high diversity,as well as,low encoding and decoding complexity.Furthermore,we proved the advantages of our suggested strategy through both theoretical results and simulations using Monte Carlo runs.The Monte Carlo simulations show that the suggested strategy enjoys better error performance compared to the current state-of-the-art distributed multiantenna strategies.In addition,the bit error rate(BER)curves drawn from the analytical results are closely matching to those drawn from our conducted Monte Carlo simulations.

CAND-IDS: A Novel Context Aware Intrusion Detection System in Cooperative Wireless Sensor Networks by Nodal Node Deployment

Cooperative wireless sensor networks have drastically grown due to node co-opera- tive in unaltered environment. Various real time applications are developed and deployed under cooperative network, which controls and coordinates the flow to and from the nodes to the base station. Though nodes are interlinked to give expected state behavior, it is vital to monitor the malicious activities in the network. There is a high end probability to compromise the node behavior that leads to catastrophes. To overcome this issue a Novel Context Aware-IDS approach named Context Aware Nodal Deployment-IDS (CAND-IDS) is framed. During data transmission based on node properties and behavior CAND-IDS detects and eliminates the malicious nodes in the explored path. Also during network deployment and enhancement, node has to follow Context Aware Cooperative Routing Protocol (CCRP), to ensure the reliability of the network. CAND-IDS are programmed and simulated using Network Simulator software and the performance is verified and evaluated. The simulation result shows significant improvements in the throughput, energy consumption and delay made when compared with the existing system.