Ki Won Sung (KTH Royal Institute of Technology)
5G systems are expected to provide a wide range of services including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Providing the enhanced and new services would require more frequency spectrum to be used for 5G. Furthermore, the characteristics of each service may fit to different frequency bands ranging from low to high bands, e.g., from sub-1GHz up to 100 GHz. Therefore, it is important to identify the frequency bands both available and suitable for 5G systems.
In the international level, the most important decisions on the spectrum allocation are made in World Radiocommunication Conference (WRC) which is organized by International Telecommunication Union (ITU) in every four years. The latest WRC was held in 2015 (WRC-15), and the next one will be in 2019 (WRC-19). In WRC-15, an agreement was made on a WRC-19 Agenda Item (1.13) to consider the identification of frequency bands for the future development of International Mobile Telecommunications (IMT), which includes possible additional allocations to the mobile service on a primary basis, in accordance with Resolution 238 (WRC-15). It entails the appropriate sharing and compatibility studies for a number of bands between 24-86 GHz in time for WRC-19. The details of the frequency bands for studies can be found in Figure 1 [1].
Figure 1: Frequency bands for studies for IMT in ITU-R until WRC-19 [1].
Apart from the higher frequency bands studied for WRC-19, parts of frequency bands around 3400-3800 MHz have obtained interest in various regions of the world. In Europe, the entire band of 3400-3800 MHz is harmonized for mobile/fixed communications networks (MFCN) according to an ECC decision [2]. The Radio Spectrum Policy Group (RSPG) considers 3400-3800 MHz to be the primary band for the introduction of 5G services provided that the frequency band is already harmonized and it offers wide channel bandwidth of 100 MHz or more [3]. In Japan, Ministry of Internal Affairs and Communications published the national report “Radio Policies Towards 2020s”, which selected 3.6-4.2 GHz, amongst others, as national candidate for 5G [4]. China also studies the availability of 3.3-3.4 GHz, and has announced a 5G trial in the 3.4-3.6 GHz band [4]. In the USA, Federal Communications Committee (FCC) has established Citizens Broadband Radio Service (CBRS) in the 3550-3700 MHz on a shared and technology-neutral basis. CBRS employs a three-tiered spectrum authorization framework to accommodate a variety of incumbent federal and commercial non-federal users on a shared basis. Specifically, it has three hierarchies of spectrum users: incumbent access, priority access, and general authorized access [5]. In addition to the 3550-3700 MHz, the “Mobile Now” Act proposes further studies on 3100-3550 MHz and 3700-4200 MHz that could offer additional 500 MHz bandwidth in the 3.5 GHz range [6].
References
[1] ICT-671680 METIS-II, Deliverable D3.2 Version 1, “Enablers to secure sufficient access to adequate spectrum for 5G”, June 2017.
[2] ECC/DEC/(11)06, “Harmonised frequency arrangements for MFCN operating in the bands 3400-3600 MHz/3600-3800 MHz”, December 2011.
[3] RADIO SPECTRUM POLICY GROUP Opinion on spectrum related aspects for next-generation wireless systems (5G), “STRATEGIC ROADMAP TOWARDS 5G FOR EUROPE”, November 2016.
[4] A GSA Executive Report from Ericsson, Intel, Huawei, Nokia and Qualcomm, “The case for new 5G spectrum”, November 2016.
[5] US Federal Communications Commission (FCC), “Amendment of the Commission’s Rules with Regard to Commercial Operations in the 3550-3650 MHz Band”, April 2015.
[6] https://www.congress.gov/bill/115th-congress/senate-bill/19, March 2017.
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