The majority of work in cognitive radio networks have focused on single-hop networks with mainly challenges at the physical and MAC layers. Recently, multi-hop secondary networks have gained attention as a promising design to leverage the full potential of cognitive radio networks. One of the main features of routing protocols in multi-hop networks is the routing metric used to select the best route for forwarding packets. In this paper, we survey the state-of-the-art routing metrics for cognitive radio networks. We start by listing the challenges that have to be addressed in designing a good routing metric for cognitive radio networks. We then provide a taxonomy of the different metrics and a survey of the way they have been used in different routing protocols. Then we present a case study to compare different classes of metrics. After that, we discuss how to combine individual routing metrics to obtain a global one. We end the paper with a discussion of the open issues in the design of future metrics for cognitive radio networks.

Routing Metrics of Cognitive Radio Networks: A Survey

As the rollout of 4G mobile communication networks takes place, representatives of industry and academia have started to look into the technological developments toward the next generation (5G). Several research projects involving key international mobile network operators, infrastructure manufacturers, and academic institutions, have been launched recently to set the technological foundations of 5G. However, the architecture of future 5G systems, their performance, and mobile services to be provided have not been clearly defined. In this paper, we put forth the vision for 5G as the convergence of evolved versions of current cellular networks with other complementary radio access technologies. Therefore, 5G may not be a single radio access interface but rather a "network of networks". Evidently, the seamless integration of a variety of air interfaces, protocols, and frequency bands, requires paradigm shifts in the way networks cooperate and complement each other to deliver data rates of several Gigabits per second with end-to-end latency of a few milliseconds. We provide an overview of the key radio technologies that will play a key role in the realization of this vision for the next generation of mobile communication networks. We also introduce some of the research challenges that need to be addressed.

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5G: The Convergence of Wireless Communications

In the year 2020, the fifth generation mobile communication will be deployed in many countries which aim to furnish a real wireless world free from present obstacles in communication system which is a great motivating factor for all the researchers, academicians and engineers. Researches are going all around the world to develop a new technology which will play a very important role in the successful deployment of 5G. The new technologies are being investigated that provide high speed, capacity, spectral efficiency, energy efficiency, pseudo outdoor communication, etc. that solves the existed problems in mobile communication system. In this work, a comprehensive study on key technologies, challenges, spectrum allocation, projects and present scenarios of 5G is discussed and described. The present study gives a detailed research to address the issues, and development correlated with 5G deployment.

A review on activities of fifth generation mobile communication system

With an ever-increasing number of applications available for mobile devices, battery life is becoming a critical factor in user satisfaction. This practical guide provides you with the key measurement, modeling, and analytical tools needed to optimize battery life by developing energy-aware and energy-efficient systems and applications. As well as the necessary theoretical background and results of the field, this hands-on book also provides real-world examples, practical guidance on assessing and optimizing energy consumption, and details of prototypes and possible future trends. Uniquely, you will learn about energy optimization of both hardware and software in one book, enabling you to get the most from the available battery power. Covering experimental system design and implementation, the book supports assignment-based courses with a laboratory component, making it an ideal textbook for graduate students. It is also a perfect guidebook for software engineers and systems architects working in industry.

Smartphone Energy Consumption: Modeling and Optimization

In the current WSN operation process, there are two major problems of data collection difficulty and network energy consumption, which seriously affects the reliability of the WSN. In this paper, the improved ant colony algorithm proposed is compared with other algorithms. Wireless sensor network nodes based on improved ant colony algorithm have lower energy consumption, and sensor nodes have more residual energy. In addition, the energy model, data transmission balance model is established and verified in the WSN transmission target function. The experimental results show that the WSN node after the improved ant colony algorithm is used to help in the determination of the location information of the public node, and then use the location information of the node to make the protocol have effective routing performance and effective target node location discrimination ability. Thus, the improved ant colony algorithm studied in this paper has important practical significance for improving the life cycle/energy consumption of wireless sensor networks. In addition, aiming at the characteristics and routing performance of wireless sensor networks, a low-power routing method based on location and direction is designed to make the message reach the target node accurately and safely, which effectively increases the data packet transmission rate.

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Numerical Optimization of the Energy Consumption for Wireless Sensor Networks Based on an Improved Ant Colony Algorithm

Both the cognitive radio (CR) and the fifth generation of cellular wireless standards (5G) are considered to be the future technologies: on one hand, CR offers the possibility to significantly increase the spectrum efficiency, by smart secondary users (CR users) using the free licensed users spectrum holes; on the other hand, the 5G implies the whole wireless world interconnection (WISDOM--Wireless Innovative System for Dynamic Operating Megacommunications concept), together with very high data rates Quality of Service (QoS) service applications. In this paper, they are combined together into a "CR based 5G". With this aim, two novel ideas are advanced: the 5G terminal is a CR terminal and the CR technology is chosen for WISDOM concept. Thus, the 5G takes CR flexibility and adaptability and makes the first step through a commercial and tangible form.

5G Based on Cognitive Radio

In the recent years Cognitive Radio (CR) technology imposed itself like a very good solution to the increasing spectrum utilization. This technology proposes the development of a new radio type - a cognitive radio - endowed with intelligence that shall sense, share, and use the spectrum opportunities (SOP) of the preexisting wireless networks, that is the channels that are not used by the licensed users. A new routing algorithm for CR networks (CRN): IPSAG - IP Spectrum Aware Geographic based Routing Protocol is presented in the paper. As suggested by the name, the IP hop-by-hop, the geographic, and the spectrum aware routing concepts were used together in the protocol's design. The dynamism and flexibility, characteristic to both CR and IP networks, made us compare the CR concept with the IP concept (a wireless versus wired flexible environment comparison); thus we assumed the IP routing approach for CRN. The proposed strategy is based on hop-by-hop routing, local decisions being taken by nodes according to both local information (CR node's neighborhood) and global information (the entire topology of CRN), channels availability, and destination location.

IPSAG: An IP Spectrum Aware Geographic Routing algorithm proposal for multi-hop Cognitive Radio networks

The 5G technology is a revolutionary technology, which will offer an "unlimited wireless world interconnection" (Badoi et al. in Wirel Pers Commun 57(3):441---464 2011. doi:10.1007/s11277-010-0082-9; Prasad 2014) and a large type of services to a vastly number of users, while using a high performance terminal. These services will most probably be provided to the users as cloud based services, with different Quality of Services (QoS) characteristics. More exactly, based on the user subscription and on the required service, the user will be served with a given QoS. Each type of QoS services class will be assured by a 5G virtual network, having a one-to-one QoS class versus 5G virtual network correspondence. In this context, the virtualization and scheduling methods will play an important role regarding the ability to provide such services in 5G networks. In this paper we present the virtualization concept within 5G networks, while also describing the existing work conducted until now in wireless networks and Future Internet fields. Two virtualization methods are also presented in this paper, based on the spectrum sharing principle used in the Cognitive Radio networks (Badoi et al. in Wirel Pers Commun 57(3):441---464 2011. doi:10.1007/s11277-010-0082-9) and based on partition principle used in Future Internet (Nejbati et al. 2012). A combination of these two methods should offer a better granularity of 5G networks virtualization, with the price of an increased complexity.

Virtualization and Scheduling Methods for 5G Cognitive Radio Based Wireless Networks

The paper is about performance evaluation of IP Spectrum Aware Geographic routing protocol (IPSAG). IPSAG is an opportunistic cognitive routing protocol which determines a source-destination route in a hop by hop manner, based on both global and local information. Simulation results are reported for a particular case of IPSAG, where the cognitive radio (CR) nodes are uniformly distributed inside the cognitive radio network (CRN), and a two-dimensional random walk model is used to model the mobility of CR nodes. The results show that the IPSAG protocol is performing well in the case of a highly mobile CRN and that the source-destination path is successfully found in the majority of the cases, especially when the network is highly populated.

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IPSAG Cognitive Radio Routing Protocol: Models and Performance

The cognitive radio (CR) technology was proposed as a solution for the lack of wireless resources in an environment with a rapidly growing number of users. The CR advances the dynamic utilization of the licensed users' unused spectrum channels by secondary users. The paper looks into large CR networks by proposing two improved variants of IPSAG (IP Spectrum Aware Geographic routing algorithm). The destination geographical location is indirectly part of the routing metric that is proposed in IPSAG, and the main assumption on which IPSAG is based is that the source can always find the destination's position. This assumption is no longer valid in a very large network, so two ideas of keeping the IPSAG flexibility without geographic bounds are proposed. Both proposals are based on dividing the network into clusters, and differ in the way of how inter-cluster routing is performed. The first proposal, GC-IPSAG, uses gateway nodes between clusters, without attempting to find where destination is located for inter-cluster routing. The second proposal, HC-IPSAG, is using an overlay network formed with cluster head nodes in order to locate the destination, and to inter-cluster route the packet.

Cornelia-Ionela Badoi

Papers

5G Based on Cognitive Radio

IPSAG: An IP Spectrum Aware Geographic Routing algorithm proposal for multi-hop Cognitive Radio networks

Virtualization and Scheduling Methods for 5G Cognitive Radio Based Wireless Networks

IPSAG Cognitive Radio Routing Protocol: Models and Performance

HC-IPSAG and GC-IPSAG algorithm proposals: Cluster based IPSAG algorithm variations for large Cognitive Radio Networks