Almost all wireless devices depend on access to the radio frequency wireless spectrum. Despite being finite, the radio spectrum must accommodate traffic that is increasing at an unprecedented rate. What is more, access is limited because of tight regulation. To address this issue, the EU-funded COEXIST (Statistical methods for coexistence in future wireless networks) project explored a method proposed by regulatory bodies that uses spectrum more efficiently and cooperatively and has the capability to help deal with this shortage. The project focused on opportunistic spectrum access (OSA), in which interest is growing given its potential to tackle several key challenges facing future generations of wireless systems, including radio spectrum scarcity. OSA increases overall spectrum efficiency by allowing non-licensed (secondary) users to employ unused licensed (primary) spectrum. It does so without any undesirable consequences to primary licensees. Project partners measured the effect of secondary access point discovery performance on the uplink capacity of cells in a mobile phone network that provides radio coverage served by a tower. The basic threshold for interference density was defined. Several optimisation issues that produce design guidelines for energy-efficient small cell networks were also identified. The team developed a framework that addresses the wireless network coexistence issue taking into account both networks and OSA protocols. The framework will be used to better understand network design for optimal spectrum use. Project members also measured the positive consequences of network coexistence on communication confidentiality and defined a new coexistence paradigm. Future work will ultimately enable multiple networks to share the same radio spectrum. Its potential to ease spectrum scarcity should contribute to meeting the needs for better, faster and more robust wireless technologies.
Radio frequency bands, radio frequency spectrum, spectrum shortage, wireless networks, opportunistic spectrum access