Cognitive radio simplex link management for dynamic spectrum access using GNU radio

The explosion of new wireless communication technologies and services has led to the increase in spectrum demand. The fixed spectrum allocation approach has resulted in current day spectrum scarcity and poorly utilized licensed spectrum. In order to overcome these problems, a new concept of accessing the spectrum, defined as dynamic spectrum access (DSA), is proposed. DSA mechanism enables unlicensed or cognitive users (CUs) to temporarily utilize a spectrum hole for a period of time. In this work, DSA based on cognitive radio (CR) technology is chosen due to its features of able to sense, learn, adapt and react according to the environment. The proposed design of the system consists of four main functional blocks: spectrum sensing, spectrum management, spectrum decision and data transmission. Spectrum management is further divided into three parts: spectrum identification, synchronization and link management. This paper focuses on the establishment of link management module in simplex mode. The implementation is done using GNU Radio and USRP SDR platform. The GMSK based and IEEE 802.15.4 standard radios, equipped with DSA capability using CR technique, have been developed and tested. The results show that the link module has successfully maintained CU’s seamless communication while the DSA mechanism offers significant improvement in terms of achieved packet rate ratio (PRR)