Cognitive Radio Networks

An assignment on development of Cellular mobile communication Generations, Namely, From 0 G to 5 G. Including a briefing on GSM, EDGE, AMPS, GPRS, And all others categories related to this field. This is totally a briefing that was just created in 15 min. ;)

We study the problem of physical layer security in massive multiple-input multiple-output (MaMIMO) cognitive radio networks (CRNs). In particular, we investigate the design of a smart jamming attack on the uplink transmission of a CRN in the presence of a single antenna jammer. The jammer is aware of the transmission protocol as well as the pilot set used for channel training in the MaMIMO systems. It attacks both the training and data transmission phases but with different powers. To have the most destructive attack, the jammer optimally divides its power between two phases to minimize the maximum energy efficiency of the secondary system. The resulting power optimization is a non-convex problem and to solve it, we propose a method to transform it into a convex optimization problem. Numerical results illustrate the effectiveness of the proposed smart jamming attack in decreasing the energy efficiency of the secondary MaMIMO system.

This report focuses on the Access network implementation of a 5G small-cell communication system using Cognitive Radio. 5G systems are the next major wireless communications standard and Cognitive Radio is being heralded as a valid implementation method when the wireless communications industry finally concludes on a fifth generation standard. The project is concerned with implementing a Beyond-Next-Generation (5G) communications network based on Cognitive Radio. A functioning model is developed in matlab, the purpose of which is to show that Cognitive Radio based 5G systems will give acceptable Quality-of-Service and energy efficiency levels.
The Access network implementation of the system involves channel assignment for the access links which provide network access to mobile subscribers. Suitable channels to service call requests are determined based on cognition.
The system performance is evaluated by estimating the system blocking and dropping probabilities and the percentage of energy saved.

Rain rate and rain attenuation predictions are vital when Rain rate and rain attenuation predictions are vital when Rain rate and rain attenuation predictions are vital when Rain rate and rain attenuation predictions are vital when designing microwave designing microwave designing microwave designing microwave satellite and terrestrial satellite and terrestrial satellite and terrestrial satellite and terrestrial communication links, such as in the Ku and Ka communication links, such as in the Ku and Ka communication links, such as in the Ku and Ka communication links, such as in the Ku and Ka bands. This paper presents the cumulative distribution functions bands. This paper presents the cumulative distribution functions bands. This paper presents the cumulative distribution functions bands. This paper presents the cumulative distribution functions (CDFs) of the predicted rain rate and rain attenuation for Uyo, Akwa (CDFs) of the predicted rain rate and rain attenuation for Uyo, Akwa (CDFs) of the predicted rain rate and rain attenuation for Uyo, Akwa (CDFs) of the predicted rain rate and rain attenuation for Uyo, Akwa Ibom State (AKS) (Latitude: 4.88°N, Longitude:

Antenna systems are critical components of any radio system operating at any frequency. The antenna and associated system comprising coaxial transmission line (commonly known as feeder cable) and any power amplifiers, RF combiners, duplex filters and so on significantly impacts on radio performance if not correctly specified, installed and operated. This paper explores the evolution of cellular antenna systems from GSM through UMTS and LTE to 5G.

In recent years, Multiple-Input Multiple-Output
(MIMO) systems have emerged as a most promising technology in these measures. MIMO
communication systems can be defined intuitively [GSS+03, PNG03] by considering that
multiple antennas are used at the transmitting end as well as at the receiving end.

The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.

The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.

Berangkat  dari  keterpurukan  bangsa  Indonesia  di  bidang pengembangan  teknologi  seluler,  hati  kami  tergerak  untuk menciptakan  karya  nyata  bagi  bangsa  Indonesia.  Buku  ini adalah  buku  paling  komprehensif  berbahasa  Indonesia mengenai  teknologi  seluler  4G,  hasil  kolaborasi  engineer, praktisi,  peneliti  dan  dosen  di  Indonesia. 

Buku  ini  membahas secara mendalam mengenai teknologi jaringan seluler  4G, dari konsep dasar, desain jaringan menggunakan software Atoll dan pengukuran  melalui  drivetest  untuk  mengetahui  Key Performance Indicator dari jaringan 4G yang sudah digelar.

Buku  ini  tentunya  sangat  bermanfaat  bagi  mereka  mahasiswamahasiswa  atau  freshgraduate  yang  gap  pembelajarannya sangat  jauh  dibandingkan  dengan  dunia  industri telekomunikasi.  Dan  juga  berguna  bagi  para  pelaku  industri untuk  merencanakan  dan  melakukan  implementasi
berdasarkan  knowledge  yang  didapatkan  di  bangku  kuliah.

Buku  ini  adalah  wadah  untuk  menghilangkan  „gap'  diantara keduanya. Buku ini dibagi dalam beberapa bagian. Bagian awal buku akan dipaparkan  bagaimana  perkembangan  industri  telekomunikasi saat ini dan apa yang harus kita persiapkan untuk masa depan industri  telekomunikasi.  Bagaimana  kondisi  industri telekomunikasi  secara  global  dapat  mempengaruhi  orangorang  yang  bekerja  di  dalamnya  secara  individual.  Kedua adalah overview  mengenai kecepatan pada jaringan 2G dan 3G dan kebutuhan jaringan 4G atas permintaan data berkecepatan
tinggi oleh mobile user. Buku ini juga membahas permasalahan spektrum 4G yang akan digunakan  di  Indonesia,  teknologi  akses  jamak  OFDMA  dan SC-FDMA yang digunakan pada jaringan 4G, arsitektur jaringan 4G  juga  konsep  mobility  dan  konsep  jaringan  heterogen  yang juga  perlu  diperhitungkan  karena  pada  saat  implementasi  4G sudah  terdapat  jaringan  2G,  3G  atau  bahkan  jaringan  wifi  dan kesemuanya harus terkoneksi dan memberikan pelayanan yang terbaik bagi user mobile phone. Selamat  membaca dan  apabila Anda kurang puas  dengan hasil karya buku ini kami sangat terbuka untuk saran dan kritik yang membangun.
Materi PDF dapat Di Download di :
http://rfoptimisation.blogspot.com/2015/04/4g-handbook-versi-bahasa-indonesia.html

Covers the state of the art of the technology and standards for reconfigurable radio systems, from self organizing networks and cognitive radio, through to reconfigurable architectures for networks and terminals

This timely book provides a standards-based view of the development, evolution, techniques and potential future scenarios for the deployment of reconfigurable radio systems.

After an introduction to radiomobile and radio systems deployed in the access network, the book describes cognitive radio concepts and capabilities, which are the basis for reconfigurable radio systems.  The self-organizing network features introduced in 3GPP standards are discussed and  before IEEE 802.22, the first standard based on cognitive radio, is described. Then the ETSI reconfigurable radio systems functional architecture and the IEEE 1900.4 standard for reconfigurable radio are examined. Finally, the author presents new scenarios and future visions that reconfigurable radio systems may bring.

Key features:-
•Examines the current standards based on cognitive and reconfigurable radio, and analyses future scenarios
•Includes a general overview of radiomobile (i.e. GSM, UMTS, HSPA, LTE) and wireless (i.e. WLAN, WPAN, WiMAX) network architectures
•Features an accompanying website features links and white papers

8
th International Conference of Networks, Communications, Wireless and Mobile Computing
(NCWC 2022) looks for significant contributions to the Computer Networks, Communications,
wireless and mobile computing for wired and wireless networks in theoretical and practical aspects.
Original papers are invited on computer Networks, network protocols and wireless networks, Data
communication Technologies, network security and mobile computing. The goal of this
Conference is to bring together researchers and practitioners from academia and industry to focus
on advanced networking concepts and establishing new collaborations in these areas.
Authors are solicited to contribute to the conference by submitting articles that illustrate research
results, projects, surveying works and industrial experiences that describe significant advances in
the areas of Computer Science & Engineering.

SUMMARY In the near future, tactical wireless communications assets may have relevance in the government/military marketplace only to the extent that they support delivery of internet (IP) traffic within a flexible, survivable tactical network architecture. The extension of HF communications to wider bandwidths gives HF the potential to serve as a valuable component of such a network architecture. The principal benefits of wider HF bandwidths come in the form of increased throughput and increased reliability (link margin). However, these are not sufficient by themselves to ensure that HF can continue to add value to tactical networks. Further issues such as latency and Quality of Service must also be addressed, and the inherent characteristics of HF communications will continue to pose distinctive challenges in these areas. In this paper, we first review characteristic challenges of IP-based network communications over disadvantaged wireless channels, including HF. We then review known techniques for effective IP-based communications under such conditions, and show how such techniques have promise to make Wideband HF a very effective bearer for IP network traffic. In the bulk of the paper, we then consider an exemplary IP-based tactical network system-of-systems, the US Army Tactical Internet or LandWarNet, and discuss roles in which Wideband HF could be beneficially applied within this system-of-systems.

In this paper, we propose, implement, and test two novel downlink LTE scheduling algorithms. The implementation and testing of these algorithms were in Matlab, and they are based on the use of Reinforcement Learning (RL), more specifically, the Q-learning technique for scheduling two types of users. The first algorithm is called a Collaborative scheduling algorithm, and the second algorithm is called a Competitive scheduling algorithm. The first type of the scheduled users is the Primary Users (PUs), and they are the licensed subscribers that pay for their service. The second type of the scheduled users is the Secondary Users (SUs), and they could be un-licensed subscribers that don't pay for their service, device-to-device communications, or sensors. Each user whether it’s a primary or secondary is considered as an agent. In the Collaborative scheduling algorithm, the primary user agents will collaborate in order to make a joint scheduling decision about allocating the resource blocks to each one of them, then the secondary user agents will compete among themselves to use the remaining resource blocks. In the Competitive scheduling algorithm, the primary user agents will compete among themselves over the available resources, then the secondary user agents will compete among themselves over the remaining resources. Experimental results show that both scheduling algorithms converged to almost 90% utilization of the spectrum, and provided fair shares of the spectrum among users.

Over several decades, advances in electronics miniaturization have been the engine for cost and performance gains in both military and commercial systems. More recently, breakthroughs in silicon-based technologies have accelerated the shift towards CMOS system-on-chip (SoC) solutions, combining complex radio-frequency (RF), analog and digital functionality. These advances, along with the introduction of newer generations of communication systems and the unprecedented surge in demand for high data rates, motivated the search for a purely digital solution for all radio standards. This, in turn, with the coexistence of the software revolution has called for the programmability of the communication systems through software to implement a software radio (SR). The concept of SR was introduced in the late 1990s as a successor to digital radio (DR). It referred to a radio transceiver where the antenna signal is sampled directly by an analog-to-digital converter (ADC) in the receive path and coupled directly to a digital-toanalog converter (DAC) in the transmit path.

The objective of this project was to design a FM receiver system with an IF-based RTL-SDR hardware device and Digital Signal Processing blocks designed in MATLAB® software. This paper presents a system which receives signals from the device antenna, demodulates using a Delay Line Discriminator circuit to retrieve baseband audio data and uses signal processing techniques to analyse the RF and baseband signal performance parameters. The system is accessed by a Graphical User Interface application which enables a user to configure the centre frequency and channel bandwidth. The application displays FFT graphs of 2.4MHz of the FM broadcast band and the demodulated audio band output, as well as outputting demodulated data to the PC audio device. Additionally, two algorithms embedded in the application are presented, one to sweep the FM band to find stations, and the other to perform static threshold SNR calculations on the FM channel over a user-variable bandwidth. This paper presents a viable alternative compared to the traditional analogue FM receiver systems, with reconfigurability, cost and real-time analysis advantages gained from digital circuitry.

The paper presents a novel bow tie quasi self complementary antenna for cognitive radio applications. The CPW
fed structure of the antenna ensures impedance matching. This antenna is designed to operate in almost the UHF band.
Here a circular bow tie antenna is converted into a wideband antenna with the help of QSC geometry and CPW feeding. The
proposed antenna shows a wide impedance bandwidth from 0.89-2.29 GHz. This antenna comprises a sensing antenna
covering almost UHF band when all the switches are off and reconfigurable/communicating antenna corresponding to
switches at various switching positions. Suitable reduction techniques are employed to reduce the size of the antenna to 86.7
x 55.5 mm which gives 24% size reduction over the conventional design.

Networks are everywhere—or so it seems. You can hardly do anything with
data that does not involve a network. Like the human networks that we are
all part of, computer networks let us share information and resources. In business,
the reliance on networks is even more pervasive than in homes or schools.
Networks help individuals and businesses alike save money, but they also help
create income. Without a doubt, networking within the home will catch on over
the next few years as it has in business. Soon, nearly all individuals in even
moderately developed nations will have networked components throughout their
homes. Those that don’t will be netologically disadvantaged because they will not
be able to learn or to function at the same level as those who are networked..........

The burgeoning demand on radio spectrum owing to explosive development in wireless communication necessitates efficient use of the available frequency spectrum. But this need is at cross purposes with the present system of fixed spectrum allocation. The use of TV white space for communication is one way of circumventing this problem. In this paper a Universal Software Radio Peripheral (USRP) is employed to detect the unused spectrum in TV band. The USRP is a hardware platform for software radio.

org/ncwc/index Scope & Topics 8 th International Conference of Networks, Communications, Wireless and Mobile Computing (NCWC 2022) looks for significant contributions to the Computer Networks, Communications, wireless and mobile computing for wired and wireless networks in theoretical and practical aspects. Original papers are invited on computer Networks, network protocols and wireless networks, Data communication Technologies, network security and mobile computing. The goal of this Conference is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas. Authors are solicited to contribute to the conference by submitting articles that illustrate research results, projects, surveying works and industrial experiences that describe significant advances in the areas of Computer Science & Engineering.

Signal & Image Processing : An International Journal is an Open Access peer-reviewed journal intended for researchers from academia and industry, who are active in the multidisciplinary field of signal & image processing. The scope of the journal covers all theoretical and practical aspects of the Digital Signal Processing & Image processing, from basic research to development of application.

Authors are solicited to contribute to the journal by submitting articles that illustrate research results, projects, surveying works and industrial experiences that describe significant advances in the areas of Signal & Image processing.

Mobile Ad Hoc Network (MANET) applications such as multimedia applications, audio/video conferencing, VOIP and webcasting need uninterrupted, stringent and inflexible Quality of Service (QoS). The provision of QoS guarantees in MANET is more challenging and difficult than wired network because of node mobility, lack of centralized control and a limited power supply. A lot of researches have been accomplished and also ongoing so far to offer QoS guarantees by designing QoS models and protocols. In this paper issues and challenges of QoS, overview of QoS routing metrics, and various performance metrics have been discussed. In future, Mobile Ad Hoc Networks (MANETs) may provide access to services in the Internet. MANETs should therefore support diverse applications and data types. This introduces a need for QoS, a process of discriminating different data types to provide them with an appropriate level of service. However, QoS can be affected by nodes performing packet forwarding attacks, packet delivery, end to end delay, node mobility and bandwidth are the dominant concern of QoS. A critical analysis of the related literature shows that research into QoS and security has typically proceeded independently.

8th International Conference of Networks, Communications, Wireless and Mobile Computing
(NCWC 2022) looks for significant contributions to the Computer Networks, Communications,
wireless and mobile computing for wired and wireless networks in theoretical and practical aspects.
Original papers are invited on computer Networks, network protocols and wireless networks, Data
communication Technologies, network security and mobile computing. The goal of this
Conference is to bring together researchers and practitioners from academia and industry to focus
on advanced networking concepts and establishing new collaborations in these areas.
Authors are solicited to contribute to the conference by submitting articles that illustrate research
results, projects, surveying works and industrial experiences that describe significant advances in
the areas of Computer Science & Engineering.

Il medium radiofonico mostra una straordinaria capacità di codificarsi come forma culturale costantemente all'altezza dei tempi. Tale capacità è dovuta alla sua mobilità ed interattività. Nonostante la modalità di trasmissione broadcasting della radio non sia cambiata, si è individuato nella "radioattività" del linguaggio radiofonico il crogiolo del suo costante processo di innovazione.
In particolare si è rilevato un certo ritmo che scandisce le tendenze evolutive del linguaggio radiofonico: si tratta di una trasformazione linguistica che affonda le radici nel tessuto sociale. Tale trasformazione linguistica avviene con un ritmo ciclico costante che  si rinnova, all'incirca, ogni vent'anni, ovvero in corrispondenza di ogni ricambio generazionale. Per questo motivo le registrazioni radiofoniche trasmesse nei decenni trascorsi mostrano parole e modi di dire ormai caduti in disuso.

8th International Conference of Networks, Communications, Wireless and Mobile Computing
(NCWC 2022) looks for significant contributions to the Computer Networks, Communications,
wireless and mobile computing for wired and wireless networks in theoretical and practical aspects.
Original papers are invited on computer Networks, network protocols and wireless networks, Data
communication Technologies, network security and mobile computing. The goal of this
Conference is to bring together researchers and practitioners from academia and industry to focus
on advanced networking concepts and establishing new collaborations in these areas.
Authors are solicited to contribute to the conference by submitting articles that illustrate research
results, projects, surveying works and industrial experiences that describe significant advances in
the areas of Computer Science & Engineering.

—The Common Control Channel (CCC) is foreseen to be adopted to establish and maintain network connections for users in future Cognitive Radio Networks (CRNs). However, the jamming attack can be easily launched to interfere with the CCC of CRNs, and causes the deny-of-service of CRNs. Most of existing anti-jamming approaches are based on the frequency hopping principle with insufficient jamming resilience performance. MIMO based anti-jamming algorithms are effective to improve the jamming resilience performance. However, they are not applicable for the low power cognitive radio networks wherein the user devices are equipped with single antenna, such as cognitive radio sensor network. Observing that relaying strategy will be widely adopted for future CRN systems, we propose a Virtual Multiple Input Multiple Output (VMIMO) based anti-jamming strategy assisted by relay nodes, which proactively mitigates the interference caused by the jamming signal. Simulations show that the bit error rate (BER) of our proposed strategy is at least 10 times lower than that of frequency hopping based approaches.

Interference alignment (IA) is an innovative wireless transmission strategy that has shown to be a promising technique for achieving optimal capacity scaling of a multiuser interference channel at asymptotically high-signal-to-noise ratio (SNR). Transmitters exploit the availability of multiple signaling dimensions in order to align their mutual interference at the receivers. Most of the research has focused on developing algorithms for determining alignment solutions as well as proving interference alignment's theoretical ability to achieve the maximum degrees of freedom in a wireless network. Cognitive radio, on the other hand, is a technique used to improve the utilization of the radio spectrum by opportunistically sensing and accessing unused licensed frequency spectrum, without causing harmful interference to the licensed users. With the increased deployment of wireless services, the possibility of detecting unused frequency spectrum becomes diminished. Thus, the concept of introducing interference alignment in cognitive radio has become a very attractive proposition. This paper provides a survey of the implementation of IA in cognitive radio under the main research paradigms, along with a summary and analysis of results under each system model.

The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.

Wireless home automation systems have drawn considerable attentions of the researchers for more than a decade. The major technologies used to implement these systems include Z-Wave, Insteon, Wavenis, Bluetooth, WiFi, and ZigBee. Among these technologies the ZigBee based systems have become very popular because of its low cost and low power consumption. In this paper ZigBee based wireless home automation systems have been addressed. There are two main parts of this paper. In the first part a brief introduction of the ZigBee technology has been presented and in the second part a survey work on the ZigBee based wireless home automation system has been presented. The performances of the ZigBee based systems have also been compared with those of other competing technologies based systems. In addition some future opportunities and challenges of the ZigBee based systems have been listed in this paper.

IEEE Communication System Project Titles 2017 | IEEE 2018 Matlab Communication Systems Projects for ECE, IT, CSE
A New Analytical Approach to Evaluate the Critical-Event Probability Due to Wireless Communication Errors in Train Control Systems
A New Framework of Filter Bank Multi-Carrier: Getting Rid of Subband Orthogonality
A Novel Spectrum Sensing for Cognitive Radio Networks with Noise Uncertainty
Application-Aware Resource Allocation of Hybrid Traffic in Cellular Networks
Bayesian Reinforcement Learning-Based Coalition Formation for Distributed Resource Sharing by Device-to-Device Users in Heterogeneous Cellular Networks
Comparison of Collision-Free and Contention-Based Radio Access Protocols for the Internet of Things
Design of Simultaneous Wireless Information and Power Transfer Scheme for Short Reference DCSK Communication Systems
Dynamic Resource Allocation for Immediate and Advance Reservation in Space-Division-Multiplexing-Based Elastic Optical Networks
Dynamic User Grouping and Joint Resource Allocation with Multi-Cell Cooperation for Uplink Virtual MIMO Systems
Energy and Spectral Efficiency of Cellular Networks with Discontinuous Transmission
Equal Interference Power Allocation for Efficient Shared Spectrum Resource Scheduling
Evolutionary Channel Sharing Algorithm for Heterogeneous Unlicensed Networks
Expectation-Maximization-based Channel Estimation for Multiuser MIMO Systems
FBMC and LDACS Performance for Future Air to Ground Communication Systems
Generalized 3-D Constellation Design for Spatial Modulation
Group Cooperation with Optimal Resource Allocation in Wireless Powered Communication Networks
Huffman Coding Based Adaptive Spatial Modulation
Joint Rate Control and Scheduling for Real-Time Wireless Networks
Joint Spectrum and Energy Efficiency in Device to Device Communication Enabled Wireless Networks
Location Privacy Preservation in Database-driven Wireless Cognitive Networks through Encrypted Probabilistic Data Structures
Multi-antenna Wireless Legitimate Surveillance Systems: Design and Performance Analysis
Multicarrier Approaches for High-baudrate Optical-Fiber Transmission Systems with a Single Coherent Receiver
Non-linear Distortion Cancellation and Symbol-based Equalization in Satellite Forward Links
Non-Orthogonal Random Access (NORA) for 5G Networks
Optimal Resource Allocation for Power-Efficient MC-NOMA with Imperfect Channel State Information
Parallel and Distributed Resource Allocation with Minimum Traffic Disruption for Network Virtualization
Resource Allocation Strategy for Multi-user Cognitive Radio Systems: Location-Aware Spectrum Access
Spectral and Energy Efficiencies in Full-Duplex Wireless Information and Power Transfer
Spectral Efficiency and Energy Efficiency Optimization via Mode Selection for Spatial Modulation in MIMO Systems
Subband Filtered Multi-carrier Systems for Multi-service Wireless Communications
TDMA versus CSMA/CA for wireless multi-hop communications: a stochastic worst-case delay analysis
The Error Propagation Analysis of the Received Signal Strength-Based Simultaneous Localization and Tracking in Wireless Sensor Networks
Training Sequence Design for Efficient Channel Estimation in MIMO-FBMC Systems
User Association and Resource Allocation Optimization in LTE Cellular Networks

The cognitive radio is an emerging technology that enables dynamic spectrum access in wireless networks. The cognitive radio is capable of opportunistically using the available portions of a licensed spectrum to improve the application performance for unlicensed users. The opportunistic use of the available channels in the wireless environment requires dynamic channel assignment to efficiently utilize the available resources while minimizing the interference in the network. A challenging aspect of such algorithms is the incorporation of the channels’ diverse characteristics, highly dynamic network conditions with
respect to primary users’ activity, and different fragmented
sizes of the available channels. This paper presents
a comprehensive survey on the state-of-the-art channel
assignment algorithms in cognitive radio networks. We
also classify the algorithms by presenting a thematic
taxonomy of the current channel assignment algorithms
in cognitive radio networks. Moreover, the critical aspects
of the current channel assignment algorithms in cognitive
radio networks are analyzed to determine the strengths
and weaknesses of such algorithms. The similarities and
differences of the algorithms based on the important
parameters, such as routing dependencies, channel models,
assignment methods, execution model, and optimization
objectives, are also investigated. We also discuss open
research issues and challenges of channel assignment in
the cognitive radio networks. (Accepted in IEEE Communication Surveys and Tutorials IF 6.4)