Alan Gatherer, Editor in Chief, ComSoc Technology News
5G shmiveG. This month Shahid and Jonathan from the Instituto de Telecomunicações in Portugal are here to tell us a scary story of a world where spectrum is in short supply and applications you thought were dead and buried have come back to demand their share of the grisly spectrum pie. Who thought the ITU could be this interesting? Viewer discretion advised and comments, as always, welcome.
The Spectrum: Scary Resource for 5G
Shahid Mumtaz and Jonathan Rodriquez
Instituto de Telecomunicações, Portugal
3G and 4G technologies have mainly focused on the mobile broadband use case, providing enhanced system capacity and offering higher data rates. This focus will clearly continue in the future 5G era, with capacity and data rates being driven by services such as video. But the future will also be much more than just enhancements to the “conventional” mobile broadband use case. Future wireless networks should offer wireless access to anyone and anything. Thus, in the future, wireless access will go beyond Human Type Communication (HTC) and expand to serve any entity that may benefit from being connected. This vision often is referred to as “the Internet of Things (IoT),” “the Networked Society,” “Machine-to-Machine communications (M2M)” or “machine-centric communications.” North American operators’ best customers are no longer humans; they are increasingly machines, such as smart utility meters, digital signage and vehicle infotainment systems [1-2].
Hence, operators need to optimize a system for lower throughput to accommodate these new customers (M2M/IoT) on one hand, and on the other hand, they need to optimize it for higher throughput for HTC. This adaptive and online optimization requires a substantial increase in the system and link capacity to cover the traffic demand of both HTC and MTC/IoT, which goes from a factor of 1000 to 10,000 times fold. Currently, there are three strategies to achieve 5G capacity demands: base station densification approaches, increase of spectral efficiency, for example through improved exploitation of the heterogeneous communication framework – and the availability of additional spectral resources.
Unfortunately the traditional approach of re-purposing spectrum is reaching its limits and there remain many other pressures on spectrum outside of the needs of 5G. Therefore, Telecommunications Union Radiocommunication Sector (ITU-R) in close collaboration with various stakeholders, including the global mobile industry, has embarked on defining the process, timeline and deliverables for the next generation of IMT systems, called IMT-2020, to realize this future vision of mobile broadband communications. To achieve a connected society, 5G services not only develop new spectrum usage approaches, including disruptive novel mechanisms, such as spectrum sharing, opportunistic usage of spectrum, etc but also require access to spectrum in a variety of bands to support the multitude of use cases, including the need to improve the quality of the service offered and to accommodate much wider channels than those in use today. In the US, the National Broadband Plan  outlines requirements for 500 MHz of new mobile and wireless spectrum below 6GHz by 2020. In Europe, the European Parliament and Council approved the first Radio Spectrum Policy Program (RSPP)  with the concrete action that the European Commission together with all Member States will ensure that “at least 1200 MHz spectrum are identified to address increasing demand for wireless data traffic; and assessing the need for additional harmonized spectrum bands”.
The 5G spectrum requirements are primarily driven by the combination of expected increases in traffic capacity demands and the support for new use cases that will be enabled by the 5G ecosystem. While the technologies that will constitute 5G are still being defined, the drivers for the development of the technology are well understood. The ITU-R has identified three main usage scenarios for 5G:
- Enhanced mobile broadband
- Ultra-reliable and low latency communications
- Massive machine type communications
Table 1 summarizes the important implications of various applications on radio interface design and spectrum for these scenarios.
|Usage Scenario||Application||High-level Requirement|
|Enhanced Mobile Broadband||UHD video (4k, 8k), 3D video (including broadcast services)||Ultra-high speed radio links, Low latency (real-time video)|
|Virtual Reality||Ultra-high speed radio links, Ultra-low latency|
|Augmented Reality||Ultra-high speed radio links, Low latency|
|Tactile Internet||Ultra-low latency|
|Cloud gaming||Ultra-high speed radio links, Low latency|
|Broadband kiosks||Ultra-high speed radio links, Low latency|
|Vehicular (cars, buses, trains, aerial stations, etc.)||Ultra-high speed radio links, Short to long range, Support for low to high-Doppler environments|
|Ultra-reliable Communications||Industrial automation||Ultra-high reliability radio links, High speed radio links, Low to ultra-low latency, Short to long range, Operation in cluttered environments|
|Mission-critical applications e.g. ehealth, hazardous environments, rescue missions, etc.||Ultra-high reliability radio links, High speed radio links Low to ultra-low latency, Short to long range, Operation in cluttered environments, Ground/obstacle penetration|
|Self-driving vehicles||Ultra-high reliability radio links, High speed radio links, Low to ultra-low latency, Short to long range Operation in cluttered environments, Operation near fast moving obstacles|
|Massive Machine-Type Communications||Smart home||Operation in cluttered environment, Obstacle penetration|
|Smart office||Operation in cluttered environment, Obstacle penetration High reliability radio links|
|Smart office||Short to long range Operation in cluttered environment, Operation near fast moving obstacles, High reliability radio links, Ground/obstacle penetration|
|Sensor networks (industrial, commercial, etc.)||Short to long range Operation in cluttered environment, Operation near fast moving obstacles, Ground/obstacle penetration Mesh networking|
Table 2 lists potential spectrum-related implications of various high-level requirements for future 5G systems.
|High-level Requirement||Potential Spectrum-Related Implications|
|Ultra-high speed radio links||Ultra-wide carrier bandwidths, e.g. 500 MHz Multi-gigabit fronthaul/backhaul|
|High speed radio links||Wide carrier bandwidths, e.g. 100 MHz Gigabit fronthaul/backhaul|
|Support for low to high-Doppler environment||Depends on the throughput requirement|
|Ultra-low latency||Short range implications|
|Low latency||Mid-short range implications|
|Ultra-high reliability radio links||Severe impact of rain and other atmospheric effects on link availability in higher frequencies, e.g. mm-wave, for outdoor operations|
|High reliability radio links||Impact of rain and other atmospheric effects on link availability in higher frequencies, e.g. mm-wave, for outdoor operations|
|Short range||Higher frequencies, e.g. mm-wave|
|Long range||Lower frequencies, e.g. sub-3 GHz|
|Ground/obstacle penetration||Lower frequencies, e.g. sub-1 GHz|
|Operation in cluttered environment||Diffraction dominated environment in lower frequencies Reflection dominated environment in higher frequencies|
|Operation near fast moving obstacles||Frequency-selective fading channels|
|Mesh networking||High-speed distributed wireless backhaul operating in-band or out-of-band|
Current global status of spectrum considered for 5G
Various administrations have started investigation and consideration of potential new bands for 5G. This investigation is similar to industry efforts to characterize new frequency ranges for 5G and the development of technical solutions towards the next generation of mobile broadband cellular systems. Given the need for more bandwidth, these investigations generally have been directed towards opportunities in the 6 GHz to 100 GHz frequency range. Various administrations’ investigation of new frequency bands for 5G around the world are at varying stages. Some regulators, including the FCC, have been investigating spectrum for 5G services by seeking public comments through domestic processes. However there are other stakeholders in the wireless spectrum map that have to be accommodated and we would like to highlight this issue by summarizing the key outcomes of WRC-15 held in Geneva, 27th November 2015:
Mobile broadband communications:
Following the growing demand for spectrum for mobile broadband services, WRC-15 identified frequency bands in the L-band (1427-1518 MHz) and in the lower part of the C-band (3.4 -3.6 MHz). WRC-15 achieved agreement on some additional portions in other bands that were also allocated to mobile broadband services in order to be used in regions where there was no interference with other services.
To counteract the difficulties encountered in finding additional spectrum for IMT in bands below 6 GHz, WRC-15 decided to include studies in the agenda for the next WRC in 2019 for the identification of bands above 6 GHz that will allow technology to meet demand for greater capacity. Administrations and industry can now concentrate on the development of necessary technologies in line with the schedule for the implementation of IMT-2020.
WRC-15 took a key decision that will provide enhanced capacity for mobile broadband in the 694-790 MHz frequency band in ITU Region-1 (Europe, Africa, the Middle East and Central Asia) and a globally harmonized solution for the implementation of the digital dividend. Full protection has been given to television broadcasting as well as to the aeronautical radio navigation systems operating in this frequency band.
Amateur radio service gets new allocation:
New allocation for amateur radio service in the frequency band 5351.5 - 5366.5 kHz will maintain stable communications over various distances, especially for use when providing communications in disaster situations and for relief operations.
Emergency communications and disaster relief:
WRC-15 identified spectrum in the 694-894 MHz frequency band to facilitate mobile broadband communications for robust and reliable mission critical emergency services in public protection and disaster relief (PPDR), such as police, fire, ambulances and disaster response teams.
Search and rescue:
WRC-15 reinforced protection to Search and Rescue beacons that transmit in the 406-406.1 MHz frequency band signals to uplink to search and rescue satellites, such as the Cospas-Sarsat system. Resolution 205 was modified to ensure that frequency drift characteristics of radiosondes are taken into account when operating above 405 MHz to avoid drifting close to 406 MHz Administrations are requested to avoid making new frequency assignments for the mobile and fixed services within the adjacent frequency bands to prevent interference in the frequency band 406-406 MHz As of December 2013, the Cospas-Sarsat System has provided assistance in rescuing over 37,000 persons in over 10,300 incidents worldwide.
Earth observation satellites for environmental monitoring:
WRC-15 agreed to new allocations in the 7-8 GHz frequency range needed to uplink large amounts of data for operations plans and dynamic spacecraft software modifications that will eventually lead to simplified on-board architecture and operational concepts for future missions of earth-exploration satellite services (EESS).
Allocations of spectrum in the 9-10 GHz frequency range will lead to the development of modern broadband sensing technologies and space-borne radars on active sensing EESS. Scientific and geo-information applications will provide high quality measurements in all weather conditions with enhanced applications for disaster relief and humanitarian aid, land use and large-area coastal surveillance.
Unmanned aircraft and wireless avionics systems:
WRC-15 opened the way for the development by ICAO of worldwide standards for unmanned aircraft systems (UAS), and identified the regulatory conditions that may be applied to such systems internationally. WRC-15 also agreed on spectrum for wireless avionics intra-communications (WAIC) to allow for the heavy and expensive wiring used in aircraft to be replaced by wireless systems.
Global flight tracking for civil aviation:
Agreement was reached on the allocation of radio-frequency spectrum for global flight tracking in civil aviation for improved safety. The frequency band 1087.7-1092.3 MHz has been allocated to the aeronautical mobile-satellite service (Earth-to-space) for reception by space stations of Automatic Dependent Surveillance-Broadcast (ADS-B) emissions from aircraft transmitters. This will facilitate reporting the position of aircraft equipped with ADS-B anywhere in the world, including oceanic, polar and other remote areas. The International Civil Aviation Organization (ICAO) will address the performance criteria for satellite reception of ADS-B signals according to established standards and recommended practices (SARP).
Enhanced maritime communications systems:
WRC-15 considered regulatory provisions and frequency allocations to enable new Automatic Identification System (AIS) applications and other possible new applications to improve maritime Radiocommunication. New applications for data exchange, using AIS technology, are intended to improve the safety of navigation. New allocations were made in the bands 161.9375-161.9625 MHz and 161.9875-162.0125 MHz to the maritime mobile-satellite service. Studies will continue on the compatibility between maritime mobile-satellite service (MMSS) in the downlink in the band 161.7875-161.9375 MHz and incumbent services in the same and adjacent frequency bands.
Radio-frequency spectrum needed for the operation of short-range high-resolution automotive radar has been allocated in the 79 GHz frequency band. This will provide a globally harmonized regulatory framework for automotive radar to prevent collisions and improve vehicular safety by reducing traffic accidents. According to UN data, more than 1.25 million fatalities occur each year on the roads around the world.
Operation of broadband satellite systems: Earth Stations in Motion
WRC-15 agreed to facilitate the global deployment of Earth Stations In Motion (ESIM) in the 19.7-20.2 and 29.5-30.0 GHz frequency bands in the fixed-satellite service (FSS), paving the way for satellite systems to provide global broadband connectivity for the transportation community. Earth stations on-board moving platforms, such as ships, trains and aircraft, will be able to communicate with high power multiple spot beam satellites, allowing transmission rates in the order of 10-50 Mbits/s.
WRC-15 decided that further studies regarding current and potential future reference time-scales are required, including the modification of coordinated universal time (UTC) and suppressing the so-called “leap second”. A report will be considered by the World Radio communication Conference in 2023. Until then, UTC shall continue to be applied as described in Recommendation ITU‑R TF.460‑6 and as maintained by the International Bureau of Weights and Measures (BIPM).
In summary, we believe that spectrum bands below 6GHz are still a priority because of their favourable radio propagation characteristics and greater coverage, particularly for sub-urban and rural environment. However, additional new bands above 6 GHz will be required to support the new applications and services that future IMT is expected to deliver. Among these bands, 6 – 30GHz range will offer the best technical characteristics in terms of balancing propagation characteristics and available bandwidths. These bands will be on agenda of WRC´19.
1 A radiosonde is a battery-powered telemetry instrument package carried into the atmosphere usually by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz.
The National Broadband Plan, see http://www.broadband.gov/plan/
“Information and Communication Technologies: Enablers of a low-carbon economy”, Acatel Lucent, White Paper, available at http://www.lucent.com/eco/docs/CMO7526101103_ICT_Enablerseco_EN_StraWhite Paper.pdf
Editor-in-Chief: Alan Gatherer (firstname.lastname@example.org)