Research, requirement analysis and initial standardisation work towards the 5th generation of cellular systems have now been under way for a few years. The system requirements, ranging from extremely low set up and end to end delay, to the perception of infinite capacity will require novel system a…
Research, requirement analysis and initial standardisation work towards the 5th generation of cellular systems have now been under way for a few years. The system requirements, ranging from extremely low set up and end to end delay, to the perception of infinite capacity will require novel system architecture solutions, but more importantly these requirements will increase the demand on wireless spectrum, accelerating the spectrum scarcity problem further. There has been a wide agreement that the fixed spectrum allocation and usage commonly adopted today are a bottleneck to 5G requirement fulfilment. Both academic and regulatory bodies have focused on dynamic spectrum access and or dynamic spectrum usage to optimize the scarce spectrum resource. These 5G systems will serve classical cellular services, but a large portion of traffic will be fed by machines and things. This machine type communication has yet specific requirements. They are much more delay sensitive and the fact that the expected tens of billions of devices will need to be reliably connected further increases the problem scale. Cognitive radio, with the capability to flexibly adapt its parameters, has been proposed as the enabling technology for unlicensed secondary users to dynamically access the licensed spectrum owned by legacy primary users on a negotiated or an opportunistic basis. It is now perceived in a much broader paradigm that will contribute to solve the resource allocation problem that 5G requirements raise.
