Introduction

Electromagnetic spectrums allotted to networks such as GSM/HSPA, 3G, 4G, TV, Wi-Fi, defense communication, radio broadcasting, mobile satellites, aeronautical satellites are not always evenly utilized. While some bands in the spectrum are heavily used and overcrowded, some other bands are idle most times and underutilized. This underutilization of bands in the electromagnetic spectrum leads to Spectrum Holes, that are nothing but available channels in the wireless spectrum. These channels are a band of frequencies which are assigned to a primary user, but at times are not utilized by that user.

With the advent of Cognitive Radio (CR), spectrum can be utilized more efficiently. A user who is unable to be serviced by a band, can access a spectrum hole at the correct time and geographic location. Thus, CR is an adaptive, intelligent radio and network technology that can automatically detect spectrum holes and utilize them for data transmission.

NetSim models CR by using the specifications in the IEEE 802.22 standard. Users can also connect a Cognitive Radio with Internetwork devices, use all the protocols that Internetworks support, and view packet and event traces.

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Figure-1: A typical Cognitive Radio Network scenario in NetSim. The topology shows two CR Base Stations communication with CR CPEs and connected to an external network via a Router

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Figure-2: The Result dashboard and Plot window shown in NetSim after completion of simulation