A cognitive cellular network, which integrates conventional licensed cellular radio and cognitive radio into a holistic system, is a promising paradigm for the fifth generation mobile communication systems.

Demand for 5G cells is driven by consumer demand where traffic is doubling each year. Now industry is preparing for a bigger challenge, an astounding 1000-fold increase in data traffic expected in this decade. This sets the stage for enabling 5G technology that delivers fast and cost-effective data connectivity, whilst minimizing the deployment cost. Despite the success of small cells and MIMO in 4G systems, there is no single technology advance that can meet this traffic demand. In fact, today's technology roadmaps depict different mixes of spectrum (Hertz), spectral efficiency (bits per Hertz per cell) and small cells (cells per square kilometer) as a stepping stone towards meeting this ambitious target.

Traditionally, purchasing additional spectrum has been a stopgap solution towards satisfying new Quality of Service demands and coping with extra load on the network. This will also continue to be a solution, as technology capability reaches the ceiling. Therefore, targeting new spectrum availability and knowing how to use this effectively becomes of the essence, particularly in an era where spectral resources are scarce and at a premium.

Investigations from the Spectrum Policy Task Force (SPTF) show that 85% of current allocated radio frequency bands are either partially or completely unused at different times across geographical areas, further compounding the drive for the main challenges facing the spectral world. Experts are interested in tackling approaches to more flexible and effective use of radio spectrum. A number of technologies and techniques have been identified as suitors for enabling 5G wireless networks across heterogeneous spectrum, among them is cognitive radio technology. This post provides an insight into the key challenges facing cognitive radio as we enter the 5G era.

The evolution towards 5G is considered to be the convergence of internet services with legacy mobile networking standards leading to the commonly used term “mobile internet” over heterogeneous networks (HetNets), with very high connectivity speeds. The objective of cognitive radio (CR) is to sense the spectrum from the real time environment and detect the non-utilized spectrum.

Next generation communication systems are expected to be intelligent in nature, as well as providing a platform for operators to effectively exploit their network resources in an era where spectral resources are at a premium. The smart cities can be designed based on cognitive radio which is meant for spectrum sensing and spatial sensing. It also uses the massive MIMO and the heterogeneous network which uses small cells called Femto / Pico cell.

Generally, Cognitive radio is the intelligent technology which senses the spectrum and location. The main goal of the cognitive radio is to sense the underutilized spectrum by the secondary user. In 5G communication system the devices such as smartphones, which searches the occupied spectrum in the form of base station downlink signals and takes the instruction from the cellular system.

CR is not the only terminology specific

to Cognitive aspect of communication

engineering, but also we have CN…

In communication networks, Cognitive Network (CN) is a new type of data network that makes use of cutting edge technology from several research areas (i.e. machine learning, knowledge representation, computer network, network management) to solve some problems current networks are faced with. Cognitive network is different from Cognitive Radio (CR) as it covers all the layers of the OSI model (not only layers 1 and 2 as with CR).

Now how we can implement CR – Cognitive Radio?

Depending on transmission and reception parameters, there are two main types of cognitive radio:

Full Cognitive Radio, in which every possible

parameter observable by a wireless node (or network) is considered.

Spectrum-Sensing Cognitive Radio, in which

only the radio-frequency spectrum is considered.

Other types are dependent on parts of the spectrum available for cognitive radio:

• Licensed-Band Cognitive Radio, capable of using bands assigned to licensed users (except for unlicensed bands, such as the U-NII band or the ISM band. The IEEE 802.22 working group is developing a standard for wireless regional area network (WRAN), which will operate on unused television channels.
• Unlicensed-Band Cognitive Radio, which can only utilize unlicensed parts of the radio frequency (RF) spectrum. [citation needed] One such system is described in the IEEE 802.15 Task Group 2 specifications, which focus on the coexistence of IEEE 802.11 and Bluetooth.
• Spectrum mobility: Process by which a cognitive-radio user changes its frequency of operation. Cognitive-radio networks aim to use the spectrum in a dynamic manner by allowing radio terminals to operate in the best available frequency band, maintaining seamless communication requirements during transitions to better spectrum.
• Spectrum sharing: Spectrum sharing cognitive radio networks allow cognitive radio users to share the spectrum bands of the licensed-band users. However, the cognitive radio users have to restrict their transmit power so that the interference caused to the licensed-band users is kept below a certain threshold.
• Sensing-based Spectrum sharing: In sensing-based spectrum sharing cognitive radio networks, cognitive radio users first listen to the spectrum allocated to the licensed users to detect the state of the licensed users. Based on the detection results, cognitive radio users decide their transmission strategies. If the licensed users are not using the bands, cognitive radio users will transmit over those bands. If the licensed users are using the bands, cognitive radio users share the spectrum bands with the licensed users by restricting their transmit power.