Bandwidth Optimization for Cognitive Radio Network via Spatial Coding in MIMO

Siva Rajasegaran; Vijayakumar P; Saminathan T

Abstract: A cognitive radio (CR) is an intelligent radio that can be programmed and configured dynamically. This kind of radio automatically detects available channels in wireless spectrum; then make changes accordingly its transmission or reception parameters to allow more concurrent wireless communications in a given spectrum band at one location. With existing cognitive network; licensed primary users (PUs) can?t work together with unlicensed secondary users (SUs) at the same frequency-time domain. SUs of cognitive network have to wait the frequency band occupied by PUs to be free. To solve the problem; a spatial coding approach for MIMO cognitive network; where a MIMO base-station with four antennas provides two different spatial codes for two users such as one PU and one SU; then the SUs can share the bandwidth of PUs. Agile & smart technology proposed by CR deal with the conflicts between spectrum congestion and under-utilization; which helps non-legitimate users to make use of licensed bands opportunistically using spatial coding & spatial multiplexing. The SDR hardware planned to use for this project is bladeRF_x40. It 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 40KLE or 40KLE Altera Cyclone 4 E FPGA (JTAG port available).

Keywords: Cognitive Radio; Cognitive Network; MIMO; Software defined Radio; Spatial coding