Heads of delegation meeting at WRC-15. Photo: ITU/D. Woldu

[Via Satellite 11-04-2015] Released coinciding with the long-awaited 2015 World Radiocommunications Conference (WRC-15), the GSM Association (GSMA) shared a study on the use of C-band spectrum, 3400MHz to 4200MHz, that says the International Mobile Telecommunications (IMT) industry needs access to this spectrum soon or it could face oversaturation in growing markets. The “Use of C-Band Spectrum for Mobile Broadband in Cities: London and Shenzhen” study, conducted by Plum Consulting with analysis from the GSMA and Huawei, evaluates the potential benefits of C-band for mobile use in the cities of London, U.K., and Shenzhen, China, as well as the repercussions of not opening up the band.

Plum Consulting’s study suggests London will experience a “capacity crunch” around 2022 if IMT is denied access to C-band, leading to slower download speeds and greater latency, subsequently resulting in poor Quality of Service (QoS) and Quality of Experience (QoE). Shenzhen reaches this crunch even sooner, according to the study, around 2020. Furthermore, the study states that these results are based on “conservative mobile data traffic demand forecasts.” Should demand climb by 30 percent more than predicted, London would reach its capacity crunch in 2020, and Shenzhen in 2018.

“The results of the study suggest that consideration should be given by governments and regulators
to the early release of spectrum in the range 3400 to 4200MHz. The likelihood of a capacity crunch in the early 2020s in both cities indicates that action is required in the short term to deliver regulatory certainty to those making investments in mobile infrastructure and to deliver the quality of experience necessary for social well-being and economic growth,” Plum Consulting wrote in the report.

The battle over C-band is the satellite industry’s biggest undertaking at WRC-15, as it is the dominant incumbent user of this spectrum. There is significant concern that if some or all of C-band is allocated for IMT, it will blot out the ability to provide services by satellite. A major source of contention is whether or not C-band can be effectively shared, with IMT usually claiming it is possible, while satellite companies argue it is not. Plum Consulting assumes that incumbent services using some portion of the frequency band would prevent mobile use of that portion in certain areas. Nonetheless, the firm states that sharing C-band is an essential part of meeting IMT demand.

“Mobile broadband services operating in the frequency range 3400 to 4200 MHz will need to share spectrum with the incumbent satellite, fixed link and [Fixed Wireless Access] FWA.
In order to make 3400 to 4200 MHz available to IMT, administrations need to establish national frameworks for spectrum sharing between IMT and the incumbent services (FSS and FS),” Plum Consulting wrote.

The C-band study only considers protection of incumbent users who
hold individual authorization. Unregistered VSATs and receive-only terminals are not. The study asserts establishing protection zones can safeguard satellite and other incumbent services. However, many in the satellite industry believe this approach will be insufficient.

“ITU sharing studies have pointed out that for FSS earth stations to be protected, they need to be separated by tens of kilometers, sometimes a few hundred. This would be particularly challenging in the Asian region where many countries are bordered by at least two countries where interference would occur,” Paul Brown-Kenyon, president of the Asia-Pacific Satellite Communications Council (APSCC) told Via Satellite in September.

Aarti Holla Maini, secretary general of the EMEA Satellite Operators Association (ESOA), told Via Satellite on Nov. 4 that there is strong evidence satellite and Broadband Wireless Access/IMT cannot successfully coexist within C-band.

“C-band BWA/IMT systems already cause harmful interference to C-band FSS. There are numerous cases of interference including from the humanitarian community in communications between Europe and Africa, which are a direct consequence of the ‘attempt to share.’ It does not work and the worst thing is, it is usually for a service that BWA/IMT systems cannot replace, so the service is simply lost,” she said.

Compared to the IMT industry, satellite industry advocates have urged a “no-change” position for C-band, essentially keeping the band in use as it is today. Many claim the IMT industry’s projections are flawed and overzealous. A study from LS Telcom in Germany earlier this year said that, while mobile operators do face challenges in meeting growing demand, this can be resolved by other means rather than using C-band. Studies from Euroconsult cite C-band as inimitable for many emerging countries.

“IMT’s request for additional C-band allocation is based on aggressive predictions for exponential growth that are much greater than current or past growth. Reports indicate that the traffic densities used to estimate future mobile spectrum demand are at least two orders of magnitude (i.e. a factor of 100 times) too high when compared with those which would be expected in any developed or developing country in a 2020 timeframe. It is highly optimistic, some would say unrealistic,” said Brown-Kenyon.

Plum Consulting’s research projects that London would generate more than $301 million over the period 2018 to 2028 — expressed in 2018 terms — and that Shenzhen would be see $138 million with IMT access to 3.4 to 4.2 GHz. Technology assumptions are based on LTE, and 5G was not considered in the study, nor were indoor small cells. The report states that access to more spectrum would enable Mobile Network Operators to roll out fewer base station sites to support the same volume of mobile data, leading to a lower network cost. Plum Consulting has conducted two other large studies on C-band in the past.