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Design and Simulation of New Beamforming
Published in Mohammed Usman, Mohd Wajid, Mohd Dilshad Ansari, Enabling Technologies for Next Generation Wireless Communications, 2020
Tanzeela Ashraf, Javaid A. Sheikh, Sadaf Ajaz Khan, Mehboob-ul-Amin
In 1999, cognitive radio (CR) was proposed by Joseph Mitola. Cognitive radio is an intelligent radio in which transceivers adjust themselves to new network condition. There are two important areas that are covered by CR: fully cognitive radio and spectrum sensing. Fully cognitive radio has the information of network parameters, and those parameters are modified where change is required for optimization of network. In spectrum sensing, researches notice location and time are imperative for proficient utilization of spectrum that is available. Cognitive radio is the best choice for detecting and allocation of vacant spectrum. This is termed as dynamic spectrum access. When the detection of vacant band radio occurs, spectrum pooling policy will be adopted where OFDMA sub bands will dwell in the actual bands. The various expressions those are involved in CR concept are
Green Communications and Networking
Published in Matthew N. O. Sadiku, Emerging Green Technologies, 2020
Key techniques of green communication mainly include cognitive network, network coding, and smart grid [11]: Cognitive network: This network can effectively improve the spectrum resource utilization efficiency and the network transmission performance. Cognitive radio plays a crucial role in improving the utilization efficiency of radio spectrum. It is capable of exploiting the residual bands when their licensed users (known as primary users) are not broadcasting on those frequencies, and to free up the channel as soon as the primary users want to access it. As illustrated in Figure 10.3, cognitive radio adds a dimension of intelligence, learning, and adaptation [12].Network coding: This involves removing redundant routes to improve the network throughput. Network coding technology saves network bandwidth and improves the link utilization.Smart grid: The main objective of the smart grid is to bring reliability, flexibility, efficiency, and robustness to the power system. The smart grid does this by introducing two-way data communications into the power grid. It provides the modern electricity grid with a high-speed, fully integrated, two-way communication technological framework. It facilitates measuring, monitoring, protecting, and controlling functions.
Strategy Learning
Published in Hamidou Tembine, Distributed Strategic Learning for Wireless Engineers, 2018
Example 2.3.1.5 (Learning in Cognitive MAC Game). The term Cognitive Radio (CR), originally coined in the late 1990s, envisaged a radio that is aware of its operational environment so that it can dynamically and autonomously adjust its radio operating parameters accordingly to adapt to different situations. Cognition is achieved through the so-called cognitive cycle, consisting of the observation of the environment, the orientation and planning that leads to making the appropriate decisions pursuing specific operation goals, and finally the updates regarding the environment. Decisions on the other hand can be reinforced by learning procedures based on the analysis of prior observations and on the corresponding results of prior updates. More than a decade after the cognitive radio concept was born researchers all over the world have devoted significant efforts addressing different technical challenges of cognitive radio networks, mainly covering fundamental problems associated with the cognitive procedures as well as technology enablers of cognitive radio concepts. Another potential offered by cognitive radio networks for bringing Dynamic Spectrum Access (DSA) to reality, thanks to the ability to identify spatial and temporal spectrum gaps not occupied by primary users (white spaces, spectrum holes), and to place secondary/unlicensed transmissions within such spaces.
A Novel Hardware Efficient High Resolution Spectrum Hole Detection Technique for Cognitive Radio
Published in International Journal of Electronics, 2023
Sushmitha Sajeevu, Sakthivel Vellaisamy
Cognitive radio can offer efficient utilisation of frequency resources. In a cognitive radio, spectrum sharing schemes can be classified into different categories. Spectral sharing in a cognitive radio can be categorised into centralised spectrum sharing and distributed spectrum sharing (Chikhale et al., 2016) based on the presence or absence of a centralised entity which controls the spectrum allocation procedure. Based on the access behaviour, spectrum sharing can be categorised into cooperative spectrum sharing and non-cooperative spectrum sharing. In cooperative spectrum sharing, interference information is shared between nodes and the spectrum is accessed in a cooperative fashion. Unlike the cooperative spectrum sharing, in non-cooperative spectrum sharing, nodes will not share information with other nodes and hence non-cooperative spectrum sharing will not result in efficient spectrum utilisation. Based on the spectrum access technique, spectrum sharing can be classified into mainly three types; underlay, overlay and interweave.
A circularly polarised monopole antenna with switchable frequency, pattern and polarisation
Published in International Journal of Electronics, 2022
Ankit Bhattacharjee, Santanu Dwari
In future, all the advanced wireless system will have to be operated in a fully cognitive radio environment because of increasing congestion in the frequency spectrum. So, wireless devices need to have adaptability in its operation and by utilising this property effectively, they will be able to reconfigure its transmission and reception characteristics according to the change in RF environment. So, the RF antennas will also have to possess such properties so that they can satisfy the criteria of such kind of cognitive systems. To fulfill such demand, a multi-parameter reconfigurable antenna perhaps is the most effective candidate. In last 5–6 years, many papers have been published on compound reconfigurable antenna (Chen & Ning, 2021; Gu et al., 2015; R. K. Singh et al., 2020; X. Liu et al., 2021; C. Liu et al., 2022; Ni et al., 2018; Singh & Saavedra, 2021; Tan et al., 2015; Tawk et al., 2017; Zainarry et al., 2018; Zhang et al., 2018), which can combine any two parameters out of three basic antenna parameters which are frequency, polarisation and radiation pattern.
Cooperative communication based access technique for sensor networks
Published in International Journal of Electronics, 2020
Cognitive radio is a new dynamic access technique that manages a certain part of the frequency spectrum and changes the communication parameters accordingly (Nosratinia, Hunter, & Hedayat, 2004). The ineffective utilisation of the spectrum triggered the emergence of cognitive radio technology. Cooperative communication is based on the idea of using relay techniques with the aim of providing lossless data communication to any wireless device (Laneman, Tse, & Wornell, 2004). By increasing the communication capacity and performance with the help of cooperation; not only the energy consumption may be reduced, but also the life of sensor nodes may be prolonged (Chen, Chen, & Meng, 2014). In addition, stable and efficient communication is achieved by expanding the coverage area with the help of multiple access techniques (Cao et al., 2013). When any wireless device desires to establish a communication with a base station; its signal may break, reflect, or weaken until it reaches the destination because of obstacles in the environment (Gao, Zhu, Liao, & Xu, 2010). In this case, a wireless relay that is in the coverage area of both the base station and the wireless device may be helpful for healthy communication. Wireless relay receives the signal from the wireless device and transmits it to the base station. Thanks to cooperative communication and its processing features, the performance of wireless sensor networks is improved. Besides, cooperative communication provides a significant increase in capacity and diversity gain for sensor networks.