#2 – Put mmWave and low band on hold – 3.5 GHz will be the primary band for 5G
Both the mmWave and sub-1 GHz spectrum bands, which are viewed as candidates for 5G deployment, have certain challenges and limitations. The mmWave band, popular for pre-5G FWA deployments, presents challenges with mobility support and providing consistent user experience. Sub-1 GHz spectrum is occupied with previous generations of mobile technologies and is not suitable to deliver the high throughput needed for 5G enhanced mobile broadband. Therefore, we believe that in 2018 the telecom industry will shift its attention and efforts towards the 3.5GHz band, especially in Europe, as this band brings a number of practical benefits.
Back in the early days of 5G research, mmWave with its enormous bandwidth attracted all the attention, to the point that it almost became synonymous with 5G. Its popularity was further enhanced by the strong push from US operators for an early launch of pre-5G fixed wireless access, intended as an alternative to last mile connectivity in areas with insufficient broadband coverage.
Although the propagation challenge of mmWave band can to a large extent be mitigated by the use of beamforming technology and site densification, its ability to support mobility so far remains feasible only in theory. In addition, mmWave’s mobile reception can be severely affected by the orientation of the human body and hands when holding the device, unless head mounted antenna becomes fashionable. We expect the early trials conducted by the US operators to show that it is too difficult to provide a consistent user experience for mobile services using mmWave band.
Sub-1 GHz spectrum can facilitate wide area coverage, but these low bands are crowded since they are already used for previous generations of mobile technologies. In addition, low bands have limited bandwidth and cannot benefit from massive MIMO. They might be useful for IoT applications, however they are not capable of delivering the high throughput needed for 5G enhanced mobile broadband.
Given the limitations of mmWave and low bands, mid-band spectrum such as the 3.5GHz band – although less exotic – brings more practical and realistic benefits. Considerable amount of 3.5GHz spectrum is available and can be directly deployed onto existing grids while still taking advantage of massive MIMO technology. This in turn delivers a significant improvement in user experience that can be properly described as 5G. 3.5GHz is also an “almost” globally harmonized band that’s ready for allocation: the exception is the USA, where it’s used as part of the CBRS band.
Following the results from the mmWave trials and also given the limitation of low bands, we believe that the industry’s attention and effort will shift to the 3.5 GHz band, which will drive up its value. We can expect to see more large-scale trials and early deployments of 5G in this band in the coming year or two, especially in Europe.