Cognitive Radio?s OFDM Window Management

Cognitive radio (to generate; transmit; receive and process of wireless signals) and a cognitive brain which learns from the environment and performs rational processes and predicts probable consequences and remembers past successes and failures. CR technology enables radio devices to use radio frequency spectrum in entirely and Sophisticated ways. CR is a novel concept that allows wireless systems to sense the environment; adapt; and learn from previous experience to improve the communication quality. Using Complex calculations cognitive radio can identify potential impairments to communications quality in their environment ? interference; path loss; shadowing and multipath fading. CR radio designed to transmit information in the presence of incumbent users; deactivating subcarriers located in the vicinity of these users to avoid interference. OFDM is the prom sizing technique that enables efficient spectrum sharing and resource allocation. But the one of the problem in OFDM is out band emission or spectral leakage that makes interference among CR user and primary user. There are Novel Interaction Techniques to reduce it by window management with overlapping windows Techniques: tabbed windows; turning and peeling back windows; and snapping and zipping windows. In this project a novel two-step side lobe suppression technique for OFDM-based cognitive radios designed to minimize the amount of out-of-band emissions that could potentially interfere with incumbent licensed transmissions in adjacent frequency bands. This paper is done by using the technique as a model which combines both constellation expansion (CE) and cancellation subcarrier (CC) side lobe reduction approaches in order to achieve lower out- of-band interference levels relative to their individual application. The above said work is going to be implementing on Blade RFx40 SDR platform and the performance is going to be analyzed. BladeRFx40 is a Software Defined Radio (SDR) platform designed to enable a community of hobbyists and professionals to explore and experiment with the multidisciplinary facets of RF communication. It supports; 2x2 MIMO configurable with SMB cable; expandable up to 4x4; RF frequency range 300MHz - 3.8GHz; Stable Linux; Windows; Mac and GNU Radio software support; On-board 200MHz ARM9 with 512KB embedded SRAM (JTAG port available); On-board 15KLE or 115KLE Altera Cyclone 4 E FPGA (JTAG port available).