by Bob Horton, consultant
The prospect of 5G and the Internet of Things by as early as 2020 are already significantly influencing the telecommunications business and the use of spectrum, which is an increasingly scarce commodity. Immense and diverse challenges are emerging. IoT requires almost perfect coverage but with cheap bit rates and a new revenue model for carriers. On the other hand, 5G is predicated on pushing the technology limits of latency and speeds. These challenges are daunting for legacy operators and an opportunity for newcomers who are emerging from several directions.
The heterogeneous nature of the next generation of mobile broadband technology suggests that 5G technology is likely to consist of several different platforms or networks which will be made available to users on a seamless basis. There might also be a need for “densification” of mobile sites to support the increase in speed, capacity and user experience.
The mobile industry and ITU WP5D have developed visions of the potential applications that will be a part of 5G. These generally include three key usage scenarios – (a) enhanced mobile broadband; (b) massive machine-type communications; and (c) ultra-reliable and low-latency communications. These 5G usage scenarios are quite diverse in their technical characteristics, as observed by the GSMA. A key focus of ITU-R studies towards the World Radio Conference in 2019 is the exploitation and capabilities of mm-Wave bands, together with the sharing scenarios which are relevant to efficient use of spectrum.
Notably, most 5G use cases do not have the extreme bandwidth and/or latency requirements that will only be supported by future 5G terrestrial technologies. As a result, satellites – both geostationary and non-geostationary – can and will play important roles in supporting the key 5G usage scenarios, including emerging 5G applications, just as satellites support 2G, 3G and 4G/LTE networks today.
Efficient multicast distribution of commonly accessed content to data caches located at each cell and small cell is going to be essential if terrestrial 5G networks are to support applications that require very low (sub-1ms) latency. Fortunately, point-to-multipoint distribution of common content is something at which satellites excels, as is evident from satellite’s historical success as a video distribution platform.
Indeed, such point-to-multipoint distribution has been identified as one of the satellite “sweet spots” in the global 5G ecosystem. IoT is also an area where complementary satellite solutions have an important role.
Technology is on the move. Dynamic spectrum access (DSA) Spectrum sharing is fundamental to effective spectrum management and a key tool in maximising the benefits achieved through use of the spectrum resource. As with all forms of resource sharing, spectrum sharing requires some degree of compromise between multiple spectrum uses (that is, services or applications) or users (individual licensees) accessing the shared spectrum.
Traditionally, spectrum sharing has largely focused on static approaches that establish co-existence arrangements defined through fixed geographic and spectral boundaries. It has been far less common to use dynamic spectrum sharing approaches, sometimes referred to collectively as DSA or dynamic spectrum management, that take advantage of time-based changes in spectrum usage and therefore availability. DSA relies on the ability of secondary users to be aware of their environment in order to maximise spectrum efficiency.
In this context, a secondary user is a user that has lower priority compared to a primary user under a DSA arrangement (i.e. it is not primary and secondary as defined in ITU Radio Regulations Article 5).
At this stage, three major techniques to enhance a device’s awareness of its surroundings have been identified: geolocation with database look up, sensing, and beacon transmissions. These techniques can be used to make use of spectrum ‘white space’, where secondary users take advantage of intermittent, occasional or itinerant use by primary users. Services can be geographically variable but relatively slow-changing, like in a frequency band used by broadcasting services, or have relatively high levels of temporal availability that is constantly changing, such as in a frequency band used by land mobile services.