A Review on Cognitive Radio for Next Generation Cellular Network and its Challenges

Abstract

Cognitive Radio (CR) is considered an intelligent technology. It improves the utilization of the radio spectrum. The increasing number of new devices has resulted in growing congestion of the ISM bands. FCC issued an order only permitting unlicensed users (secondary users) to operate in white space without interfering with licensed users (primary users). Cognitive Radio Networks (CRNs) provides a solution to the problem of additional spectrum requirements by utilizing the spectrum more efficiently. CR is able to sense the spectrum and share the spectrum with unlicensed users. There are number of popular spectrum sensing techniques in CR such as cyclostationary feature detection, energy detection and matched filter detection, which capture the best available spectrum. They use a spectrum dynamically in wireless communication network. A CR with multicarrier technique (OFDM and FBMC) are the next generation of advanced cellular network, which would provide better spectrum utilization and therefore have greater capacity. In this study we have described and reviewed CR technology and its numerous features that may play a very essential role in the field of next generation wireless communication networks.

A Review on Next Generation Mobile Communication-5G

“…The significant advantages of this technique are No CP, lower spectral side lobs and less out-of-band leakage. As compared with the current OFDM system, FBMC offers many advantages and it is considered to be a perfect solution in minimizing the adjacent band interference [5,10]. So FBMC is the required candidate for the 5G mobile communication.…”

“…The present 2G/3G/4G networks are designed for licensed spectrum, meaning that only licensed users can access this spectrum. In the future, unlicensed users can also access the licensed user's spectrum and vice versa with the help of spectrum sharing techniques (Dynamic Spectrum Access) [2,5].…”

“…The two primary steps in CR are spectrum sensing and spectrum sharing. Spectrum sensing is the initial step in this technology; it will sense the entire spectrum and detect the free or unused spectrum [5]. Secondly, it will share that unused spectrum to the user, who request to access the spectrum.…”

“…So as compared with the previous technology, 4G OFDM technique achieved a greater throughput. One of the significant advantages of this technique is "No ISO" because of the sub-carriers, which is orthogonal to each other and the wider bandwidth is split into narrow bands [5]. This technique is presently used in the 4G LTE system and WiMax system, but the Cyclic Prefix (CP) present in the OFDM symbols, creating a spectral loss because of repeating the same symbols and it affects the throughput of the system.…”

Mobile Communication - Past, Present and Future: a Review

“…Each subcarrier will be independent of each other, there will be no inter carrier interference, this technique is known as Orthogonal Frequency Division Multiplexing (OFDM), which is adopted in current 4G LTE technology. This technique is very fast at data rate, as compared with the previous technology (3G), high spectrum efficiency and enhanced security [3]. In today's Business world 4G LTE technology plays a vital role, around 1.3 billion people are getting benefit from this technology.…”