Researchers boost wireless cellular systems Wireless cellular systems are currently limited by their own interference. Researchers in Spain are investigating how to address this by improving spectral efficiency. Digital Economy © Shutterstock Over the last 20 years, huge advances have been made in wireless cellular systems, for example in the field of forward error correction, power control, link adaptation and incremental redundancy, alongside massive increases in processing power. This means that these systems are now operating close to their capacity, and frequency reuse patterns are becoming universal. Inter-cell interference is one of the biggest problems facing wireless cellular systems. Traditionally, a user is assigned to a cell and then communicates with that cell site while causing interference to all other sites in the system. Researchers involved in the 'Network multiple-input multiple-output for advanced wireless systems' (Netmimo) project want to iron out this difficulty. They began with the premise that in the uplink, inter-cell interference is merely a superposition of signals that were intended for other cell sites - in other words, signals that happen to have been collected at the wrong place. The scientists believe that if these signals could be properly classified and routed, they would in fact cease to be interference and become useful in the detection of the information they carry. Hence, ultimately, the goal should be to serve all users through all the sites within their range of influence. The research team is taking up the challenge, saying that this is theoretically possible by virtue of the fact that the cell sites are connected by a powerful backbone network. This ambitious idea leverages the almost unlimited bandwidth available in optical wire-line networks to transcend the burden of wireless inter-cell interference. Hence, according to the Netmimo framework, the notion of a cell gets blurred once users are no longer assigned to specific sites, and ultimately, there is a network of sites serving a pool of users.