In 5G networks, spectrum will play a critical role to support new ultra-high speed and low latency services like mission-critical IoT, Enhanced Mobile broadband and fixed wireless access. Each 5G spectrum band will have unique capabilities and performance characteristics to support each use case.
Initial experiences show that Telcos need to consider a mix of spectrum bands and technologies to successfully achieve 5G long term vision and provide superior performance.
In most countries, the availability of new frequencies for 5G is limited to very few bands and regulated by very complex auctions and allocation system. The regulatory conditions for releasing 5G new bands will have a massive impact on the ability for Telcos to roll out 5G networks faster and also for the device ecosystem to further develop. The regulatory framework is the key for affordable and sustainable development of 5G.
Table1: Current spectrum outlook
5G technology provides far better flexibility in how spectrum is utilized. Technologies such as massive MIMO, carrier aggregation, dynamic spectrum sharing could help Telcos launching plans and facilitate broader deployments.
The 5G spectrum range
5G requires large quantities of spectrum holdings to delivery the high-speed, high capacity services vision. Telcos will need at least 100Mhz on mid-bands to delivery 1Gbps downlink speeds for Mobile broadband subscribers. Without enough spectrum allocation, 5G experience will be similar or worst than today's 4G experience.
3GPP Release 15 has identified spectrum within two frequency ranges of 450MHz–6GHz (FDD and TDD) and 24.2–52.6GHz (TDD) for 5G New Radio. The sub-6GHz range includes frequencies below 1GHz as well as the mid-range bands around 2.3GHz and 3.5GHz. The higher range covers the high-capacity millimeter wave (mmWave), bands
Table 2: Summary of existing bands proposed for 5G
All spectrum bands used today are expected to move to 5G in the coming two years. Nevertheless, mmWave can provide operators with 400-600Mhz of spectrum to achieve ultra-high-speed performance.
The bands below 1Ghz are coverage bands. They lack enough bandwidth to provide faster speeds associated with 5G but play a vital role in providing nationwide coverage and enabling massive IoT use cases.
The mid-range bands between 3.3Ghz to 4.2Ghz will be the leading bands for addressing capacity and coverage in urban environments. Despite the bands above 6GHz, including the mmWave bands, will be more focused on addressing use cases like residential or enterprise Fixed wireless access or providing hotspot capacity booster.
Table 3: Spectrum and use cases
5G Mid-range bands landscape
For Mobile internet use cases, the frequencies around 3.5GHz have the advantage of using TDD mode operation. This mode can support the asymmetric allocation of downlink versus uplink capacity enabling more efficient use of spectrum resources. 3.5Ghz also have similar range characteristic as 1800Mhz for 4G, due to the improvements on 5G NR. These benefits will make these bands the lifeblood of 5G mass-market deployments.
3.3Ghz to 4.2Ghz bands have gained global support for 5G and are being adopted in most markets, except countries where Fixed satellite services occupy this frequency range. In these case, regulators are exploring alternative mid-bands frequencies, but they are having more challenges to find enough spectrum and device ecosystem support.
Table 4: Mid-bands allocation per country
In Asia-Pacific, Australia has already awarded 250MHz of spectrum in the 3.5GHz band in two auctions, and South Korea has licensed 280MHz in the 3.5GHz band. India and Hong Kong are planning to award 200MHz of mid-band spectrum this year, and New Zealand will do the same in 2020. Other countries like Malaysia, Thailand, and Indonesia are experiencing challenges to clear up this band in the near term due to the existing satellite services.
In the US, the 3.5Ghz band is currently used for various type services including satellite, navigation systems, and broadcasting, therefore is not available for 5G. US regulator is currently investigating different approaches for sharing and options for clearance. One clearance option under consideration is private spectrum auction by satellite users of 3700 – 3880 MHz for mobile and 20 MHz guard band with spectrum above 3900 MHz retained for satellite
US telcos have taken alternative approaches due to 5G mid-band spectrum scarcity. Sprint has launched 5G services using the 2.5GHz band (TDD) which should provide a more competitive capacity and support for smartphone users in urban areas.
Meanwhile, Verizon and AT&T, have launched 5G leveraging on mmWave spectrum to address the Fixed wireless access use case. The lack of a mid-band will limit AT&T and Verizon to provide 5G services to smartphone users. One possibility is to use other legacy bands for 5G coverage by refarming and using spectrum aggregation or leverage on dynamic spectrum sharing between 4G and 5G bands.
While 5G trials have achieved ultra-fast speeds well over 1Gbps, early commercial deployments offer a more realistic picture in terms of speed as well as coverage. Initial 5G deployments using the mid-range bands are delivering significant performance improvements over 4G varying from 1.5 times to 2 times faster speeds.
In Korea, KT median throughput downlink speed is in the range of 300Mbps. In the UK, EE has seen between 100Mbps and 300Mbps on its 3.5GHz network after their launch earlier this year.
For most mid-band early launches, users report widely variable performance; however, with maximum speeds at around 600Mbps but also dropping below 100Mbps occasions. Typically, rates of between 200Mbps and 300Mbps are being achieved in both cases.
Sub-1GHz bands landscape
The sub-1GHz bands will be used for 5G wide-area coverage only, as individual telcos are likely to receive less than 15Mhz of the spectrum each. This spectrum amount will not be enough to support high-speed 5G services. However, these frequencies will be used for rural coverage, low capacity IoT services, or 4G anchor band for 5G Non-Standalone standard.
For 5G NSA, the capacity in the lower FDD band can be used to provide a supplementary uplink carrier for 5G in the higher TDD band. This combination will boost the available capacity in the mid-range band for 5G service.
In Europe, the EU is working on freeing up the spectrum in the 700MHz band by summer 2020. France, Germany, Italy, and Sweden have already auctioned spectrum the 700MHz band. Other countries, including the UK, are expected to start auction later in 2020.
mmWave bands landscape
High-frequency bands ranging from 6GHz to 30GHz can offer bandwidth capacity in the hundreds of megahertz but with the drawback of limited coverage. Currently, most markets are adopting either 26GHz or 28GHz mmWave bands. In the coming months, additional mmWave frequencies above 28GHz will be released.
In the US, the American regulator has auctioned 700MHz of new spectrum for 5G services in the 24GHz band, raising more than USD 2Bn. New spectrum auctions for 37GHz, 39GHz, and 47GHz bands will start in December releasing total 3,400MHz of total spectrum.
American operator Verizon's 5G Ultra Wideband service uses the mmWave band at 28GHz for fixed-wireless access service as well as limited "hotspot" 5G coverage. T-Mobile and AT&T are also using mmWave frequencies for hotspots.
Also during November 2019, the WRC-19 will study the inclusion of bands in the range 20GHz up to 86GHz for future 5G services. US, South Korea, and Japan were already assigned frequency bands between 27.5–29.5GHz.
In Europe, The European Commission has established the 26GHz band as the third "pioneer band" for 5G alongside 3.5GHz and 700MHz. Regulators will be able to authorize the use of the 26GHz band by December 2020. Consultations on the allocation of the 26GHz band have already begun in Portugal, Belgium, and Norway. Ireland awarded 26GHz spectrum previously in April 2018, with 19 lots of 2×28MHz auctioned off for USD 1.40Mn.
The current user experience of Fixed wireless access is limited by mmWave's poor propagation characteristics, typically to within tens of meters of cell sites. This limitation may persist until more significant densification of the network can be achieved using more small cells. Until that day services will revert to 4G outside the hotspot coverage area. In terms of speed, Verizon has stated that customers should expect between 450Mbps and 1Gbps. Some users have reported speeds above 1Gbps, but problems such as overheating of devices in hot weather have caused customer complaints.
Also, FWA services using mmWave spectrum appears to be more stable when a line-of-sight connection between the cell site and the subscriber's CPE is achieved. Users of Verizon's 5G Ultra Wideband FWA service report experiencing speeds of around 300Mbps, sufficient to support a range of smart home applications such as video streaming, gaming, and video chat. Performance of 5G FWA can depend on the choice of CPE, with outdoor CPE generally offering faster speeds than indoor and lower degradation of service due to signal interference caused by rain or foliage.
Other new bands are in the pipeline
Regulators in many markets are already exploring the possibility of freeing up additional bands for 5G. UK regulator is already planning to free up more spectrum by the end of 2022 in addition to the 190MHz of spectrum in the 2.3GHz TDD and 3.4GHz bands licensed during 2018. This is likely to include the 1492–1517MHz band, around 168MHz in the bands between 7.9GHz and 8.4GHz, and 2.25GHz of the spectrum between 24.25GHz and 26.5GHz. The regulator is also considering additional mmWave frequencies in the range up to 71GHz.
Spectrum strategy is more critical than ever
The need for higher speed and capacity than previous technologies increases the importance of spectrum as a crucial asset for 5G success. Recent auctions of frequencies in the mid-range bands around 2.3GHz and 3.4–3.8GHz have seen operators seeking to secure enough blocks of spectrum sufficient to support viable 5G services, but also with a view in many cases to use these in conjunction with their existing spectrum assets.
Telcos 5G spectrum holdings can also be a valuable marketing asset. Three UK, which plans to launch 5G fixed wireless access services during August, claims to be building the country's fastest 5G network leveraging on 100MHz contiguous blocks of spectrum in the 3.4–3.8GHz band. Three UK has combined their 20Mhz awarded in 2018 5G with Three's pre-existing spectrum assets in the same band placing them in a better competitive situation.
Vodafone Spain, which launched 5G services in 15 cities during June, acquired 90MHz of contiguous 3.7GHz spectrum at auction in July 2018. The operator is quoting speeds up to 1Gbps, reaching 2Gbps by the end of the year.
Even though network traffic will grow over time, speeds will keep pace as Telcos start to use more of their spectrum resources than is currently possible. For example, as legacy spectrum is refarmed for 5G, Telcos will be able to dedicate more of their 5G spectrum resources to boost downlink speeds, while bringing new technologies such as dynamic spectrum sharing and carrier aggregation together.
Spectrum costs and auction processes
Spectrum is very hard to predict component of 5G network costs and hence one of the most disputable. Some of the highest prices paid for mid-band 5G spectrum so far have been realized at recent auctions in Italy, Germany, and the UK. Latest auction prices are not close to the sky-high prices paid for 3G spectrum 20 years ago, but they are putting a considerable burden on 5G business case and viability.
Table 5: 3.4-3.8Ghz spectrum price levels
In Germany, four operators competed fiercely for spectrum in the 3.5GHz and 2GHz bands completing an auction of more than €6.5bn. Although Deutsche Telekom emerged as the winner with 130Mhz of spectrum in both bands for more than €2Bn, the Telco has complained about the high prices paid and the impact on their ability to roll out services faster. This complaint is related to the stringent coverage obligation attached to the new license, that requires bidders to provide 98% of German households with 100Mbps connection by 2022.
Table 6: Mwave spectrum price levels
Other operators across Europe have shared these concerns about both spectrum costs and how auction processes are structured. Many regulators are creating auction schemes that will make very difficult to develop a 5G business plan. Either phasing the release of the spectrum or providing uneven spectrum packages for telcos in the same country.
Table 7: 700Mhz spectrum price level
5G Private networks: A separate spectrum allocation?
Alongside the allocation of new spectrum for public 5G networks, there is perceived to be a growing demand for the distribution of frequencies for private networks, to support use cases such as mission-critical and business-critical industry connectivity.
Frequencies ranging from 700MHz to 3.5GHz and higher are already being selected for private LTE by some regulators. There is also a suggestion that frequencies licensed to but not being used by mobile operators could be brought into service. In Germany's recent auction of 2GHz and 3.6GHz spectrum, the regulator held back 100MHz of spectrum in the 3.7GHz and 3.8GHz bands specifically for industrial and regional use.
In the UK, the regulator is inclined to reserve the mid-band spectrum between 3.8GHz and 4.2GHz for new "innovative" private 5G deployments. In a recently published paper, the regulator stated its intention to review proposals for greater shared access in the 3.8–4.2GHz band, which could be used for private networks. Other countries are also studying this interest.
This situation could jeopardize even further Telco's role, and business case for 5G. Especially as a big part of the expected new revenue streams will come from industries becoming digital.
Table 8: Telcos support for private networks in 5G
Telcos are objecting spectrum being sold off for private networks. Several telcos have stated that the with current limitation of 5G spectrum for national deployments assigning spectrum directly to private networks will deepen this challenge more. Telcos are also saying that 5G standard has been developed with the ability to support public and private network needs by leveraging on technologies like network slicing.
In the US, the use of license-free spectrum and shared access is gaining more extensive support through the Citizens Broadband Radio Service (CBRS) initiative. This initiative makes frequencies at around 3.5GHz available free for private network use cases such as in-building coverage, public spaces, and industrial IoT.
Ofcom has proposed a similar approach to sharing spectrum in the 3GHz to 4GHz range in the UK and regards these frequencies as suitable for innovative services such as Industry 4.0.
Critical enablers for 5G: DSS, Carrier aggregation and Dual-Core
Dynamic spectrum sharing (DSS) is a technology designed to allow 5G operators to make more efficient use of existing spectrum when introducing 5G services. It does so by sharing the same spectrum band between 4G and 5G, with frequency resources being allocated dynamically and according to demand between the respective networks, within milliseconds. DSS makes spectrum remove the need to refarm or dedicate spectrum only for 5G services. Several operators are exploring options to launch 5G services in existing 4G bands such as 2.6Ghz FDD or even 1800Mhz.
DSS can be implemented with just a software upgrade in networks that are 5G NR-ready. For Telcos that have yet to ready their networks for 5G, DSS might help to accelerate their 5G plans. DSS technology is even more relevant when Telcos lack sufficient mid-band spectrum to provide a competitive 5G mobile broadband service. In either case, 5G handsets capable of supporting the technology are required.
Operators with large amounts of TDD spectrum, such as in Band 41, can also dynamically assign frequency within their TDD bands between TD-LTE and 5G NR. Although still incurring overheads, this is no longer an issue compared with using a 10MHz or 20MHz channel for FDD low band, because of the large amount of TDD spectrum available.
Ericsson recently announced their work with Swisscom to launch spectrum sharing by the end of this year, using the 3.5GHz band and a low-band component. This will help the operator to achieve its target of 90% population 5G coverage by end-2019, says Ericsson.
Right now, 5G deployments around the world use an LTE core and radio access network with the addition of a 5G carrier. The next step is to move from that scenario, non-standalone 5G, on to full-blown standalone 5G with a dedicated core and RAN.
At a high-level, dynamic spectrum sharing allows operators to leverage software to operate 5G and LTE will in the same band at the same time based on the needs of the end-user. Verizon CEO Hans Vestberg has position dynamic spectrum sharing as a critical strategic element on Verizon's plans expand its 5G offering from concentrated coverage using millimeter wave spectrum to more extensive area coverage using low- and mid-band frequencies
Writed by : Sebsatian