Intelligent RSSI based tuning of receiver PLL of a cognitive radio

The popularity of radio communication is increasing day by day but the availability of free radio spectrum is proving to be more difficult. Paradoxically a sizable part of total radio frequency spectrum is either underutilized or not utilized at all. To overcome this situation, Cognitive Radios or radios with built in automatic sensing facility have been thought of. Research activity is taking place to implement this type of radio. In this paper we have implemented a scheme in which the radio receiver will detect Received Signal Strength Indicator (RSSI) condition of a particular channel and will force the Phase-Locked-Loop (PLL) to lock to a new frequency or channel with proper value of Signal-to-Noise-and-Distortion (SINAD) automatically. The scheme was implemented in the laboratory set up through emulation and the result has been described in the paper.