ISM-Advanced: Improved access rules for unlicensed spectrum

Access to unlicensed spectrum has thus far been based on simplistic rules, such as a transmission power limitation, requirement for tolerance of interference, and a relaxed out-of-band transmission mask. Such rules originate from the rudimentary applications originally envisaged for such spectrum, which don´t consider the current technical capabilities of radio devices. This paper introduces the concept of “ISM-Advanced”, which incorporates Cognitive Radio capabilities into the rules for unlicensed spectrum access in ISM bands. It is argued and shown that the introduction of such capabilities can significantly improve the efficiency of spectrum usage, as well as the quality of service that is experienced by spectrum users. Moreover, constraints such as on transmission power can be relaxed under the proposed scheme, and the stability in performance of unlicensed spectrum can be improved. Among many other benefits, these characteristics facilitate use of unlicensed spectrum by quality-of-service-conscious telecommunication service entities such as cellular (LTE) operators, likely in aggregation with and supplementing their licensed spectrum. In view of the increased use and allocations being seen of unlicensed spectrum, it is suggested that the policies and technical rules that govern dynamic spectrum access in ISM bands be reviewed bringing them up to a level matching technical capabilities of modern radio equipment using Cognitive Radio technology.