APG15-2/INP-59
/ ASIA-PACIFIC TELECOMMUNITYThe 2ndMeeting of the APT Conference Preparatory Group for WRC-15 (APG15-2) / Document:
APG15-2/INP-59
01 – 05July 2013,Bangkok, Thailand / 01 July 2013
Korea (Republic of)
PRELIMINARY VIEWS ON WRC-15 AGENDA ITEMS1.1, 1.2, 1.3 AND 1.4
Agenda item 1.1: to consider additional spectrum allocations to the mobile service on a primary basis and identification of additional frequency bands for International Mobile Telecommunications (IMT) and related regulatory provisions, to facilitate the development of terrestrial mobile broadband applications, in accordance with Resolution 233 (WRC-12);
Resolution 233 (WRC-12)–Studies on frequency-related matters on International Mobile telecommunications and other terrestrial mobile broadband applications
1. Background
WRC-15 AI 1.1 was adopted to consider additional spectrum allocations to the mobile service on a primary basis and identification of additional frequency bands for International Mobile Telecommunications (IMT) and related regulatory provisions, to facilitate the development of terrestrial mobile broadband applications, in accordance with Resolution 233(WRC12). In accordance with WRC-15 AI 1.1, ITU-R Working Party 5D is taking into account the suitable frequency ranges in preparation for the WRC-15 Agenda Item 1.1. And JTG 4-5-6-7 is responsible for the development of draft CPM text forthis agenda item taking into account spectrum requirements from WP 5D and WP 5A. ITU-R WP 5D is considering suitable frequency ranges for new spectrum for IMT and submitted some suitable frequency ranges to JTG 4-5-6-7 (see Documents JTG 4-5-6-7/46 and JTG 4-5-6-7/117).
Frequency bands for IMT were identified bandwidths of 230 MHz at WARC-92, 519 MHz at WRC-2000 and 428 MHz in Region 2 and some countries in Region 3 and 392 MHz in Region 1 at WRC-07, as shown in Figure 1.
FIGURE1
Identification for IMT spectrums by WRCs
2.ITU Studies on Demands for Mobile Broadband
The previous ITU-R studies on the future mobile market for the year 2020 considered a diverse range of services that require higher data rate delivery than is currently available. Report ITU-R M.2072 approved in 2006 described various aspects of the future mobile market and estimated the total volume of mobile traffic for the year 2020. And then ITU-R revisits the market estimation the Report ITU-R M.2243 in 2011. Compared with the Report ITU-R M.2072, the new market forecast estimated almost twice larger mobile traffic demands than those in Report ITU-R M.2072. Furthermore, it is expected that the real mobile traffic will be further increased because of technology advances. For instance, mobile traffic was rapidly increasing by about 357 fold as of April 2013 (64,498 TB) compared to that in January 2009 (180 TB) after nation-wide LTE networks were deployed in Korea.
ITU-R developed Report ITU-R M.2078 to estimate spectrum requirements in order to prepare for WRC-07 and the estimated total spectrum bandwidth requirement for the year 2020 is ranging from 1280 MHz to 1720MHz.However, currently identified spectrums to IMT do not even meet spectrum estimation, which forecastat least 1280MHz in Report ITU-R M.2078, and some of these bands were not globally harmonized. It is noted that the rapid deployment of smart devices was not consideredwhen Report ITU-R M.2078 was developed and the growth of IMT network data traffic is expected to drastically accelerate in the coming years taking into account new market trends and market drivers.
In addition, since current ITU-R methodology of spectrum requirements calculation applied traffic data and network capacity on the average basis within a certain district, high peak demands within small areas are not well captured. This high peak demands may accommodate all traffic demands of macro-cell, micro-cell and pico-cell/hot spot in those certain areas that require really high peak capacities such as shopping mall, airport, crowded-subway/bus and terminal, etc.
3. Economic Impacts of Broadband
Report ITU-R M.2243 describes that mobilecommunications including mobile broadband communications have been playing important roles in the economic and social developments of both developed and developing countries, such as growth of economy, mitigation of digital divide, improvement of life quality, and facilitation of other industries.New traffic forecasts are provided by a number of industry sources for the forecast up to 2015 and one source for the forecast between 2015 and 2020 taking into account new market trends and market drivers. Developing countries will also play an important role in the next period, due to their large markets and relatively low deployment levels of IMT up until now. With the introduction of higher capability networks and enhanced devices, even more user friendly interfaces will emerge to make mobile applications more generally accessible.
In a World Bank Report[1], it was found that in low- and middle-income countries every 10percentage point increase in broadband penetration accelerates economic growth by 1.38percentage points: more than in high-income countries and more than for other telecommunications services.
ITU-D published the Report “The impact of broadband on the economy (April 2012)” and this Report indicates the multiple effects of the economic impact of broadband: contribution of broadband to GDP growth, impact on productivity, impact on job creation, creation of consumer surplus and impact on firm efficiency.
4. Benefits for Mobile Broadband
The growth of IMT network data traffic is expected to accelerate driven by new devices and applications especially, requiring higher data rate and real-time delivery in dense urban areas with small cells. And a variety of short range applicationswould be introduced based on IMT technologies and networks in the near future and cause a further explosive increase ofmobile data traffics.It means that these usages may deteriorate capacity problems in a specific area or at a specific time in which a number of users demand simultaneously high performance data services, (e.g., live HD video) leading to a peak data rate.
It is quoted that, as described in Report ITU-R M.2243 released in 2011,“Smartphones represent only 13% of total global handsets in use today, but they represent over 78% of total global handset traffic.The global mobile data traffic report also states that the top 1% of mobile data subscribers generates over 20% of mobile data traffic, down from 30% one year ago. According to a mobile data usage study conducted by Cisco, mobile data traffic has evened out over the last year and now matches the 1:20ratio that has been true of fixed networks for several years. Similarly, the top 10% of mobile data subscribers now generate approximately 60% of mobile data traffic, down from 70% at the beginning of the year”[2].
Currently, RLAN networks play a role to cover data offloads coming from mobile traffic demands in dense areas and is generally expected to play a continuing role for mobile data traffic offload as mobile data traffic is increasing. However RLAN users can suffer from some problems such as mutual interference in dense urban areas, security and user’s privacy because it is used in license-exempt bands.In addition to RLAN network use for data offload, higher frequency IMT networks also could be a new benefit to operators because this technology would belong to the operators’ network and this enables operators to provide IMT services in licensed spectrum.
Higher capacity and improved QoS for multi-media services and managed high speed access based on licensed spectrum bands create operators’ business opportunities in data analytics, unified communications and cloud services, etc. One of the mobile operators’ challenges in data analytics is the fragmented nature of user behaviour and their use of mobile services. However, bringing the traffic into the operators’ network will create a good basis to better understand user behaviour and could be leveraged for more precise marketing to a specific consumer.
Licensed spectrum also can bring benefits for differentiating features or services to the consumer by high quality of services, security and reliability, and would encourage consumers to spend more time using the mobile network. For example, operators that migrate their 3G to LTE experiences higher average data traffic in their LTE network than that in 3G networks. In Korea, the average data consumption by LTE users is 40% higher than that for 3G users. This improved QoS and reliability will bring opportunity to operators differentiating their on-demand multimedia services, home security service etc.
In this sense, multi-Gbps data rate per user should be taken into account to implement the coming mobile broadband services requiring Quality of Experience (QoE) and high mobile data rates that requires additional spectrum to accommodate wide system bandwidths.
However IMT-Advanced technologies will have a difficulty to provide higher performance mobile communication services to provide multi-Gbps data rates, e.g. the requirement of IMT-Advanced of 1Gbps peak data rate in a nomadic environment in Recommendation ITU-R M.1645. Although it is certain that IMT-Advanced technology can support a peak data rate higher than 1Gbps, but it cannot support this peak data rate uniformly across the network because of the nature of cellular systems.
Figure 1 related to the CDF curve of user data rate shows how many users can be served at a 1 Gbps peak data rate when assuming total 100MHz bandwidth is used and there is only one user to be served in a cell. From Figure A-1, we know that few users can enjoy the high data rate which is close to 1 Gbps even when 100MHz bandwidth is assumed.
Figure 1 Limited number of users for peak data rate
Recently, 3GPP has been studying technologies for new Releases in order to improve the overall system performance. One of study items looks at higher order multi-antenna technology, so called as Full-dimensional MIMO (FD-MIMO), which is able to provide more spectral efficiency. Also the study regarding enhanced small cell has been actively discussed for its possibility of the benefits in terms of spectrum reuse. Another item is carrier aggregation which will provide the wider bandwidth.If the number of BS antennas is 64, compared with 2 BS antenna, it gives almost 6 times and 15 times efficiency increase for the average cell throughput and edge user throughput respectively, even though the number of UE at the receive side is reduced by half from 2 to 1.
However, it may be difficult to increase the number of antenna elements in lower frequency bands because of the limitation of form factor size. It is easier to accommodate the large number of antenna if the operating frequency goes up to higher bands.At a 3 GHz operating frequency, for example, 64 H (horizontal) linear array antenna with 0.5 lambda spaces between two antenna elements requires over a 3 meters length of space in the horizontal dimension. On the other hands, 64 antennas in the 30 GHz operating frequency ranges require only 0.3 meters.
As for carrier aggregation technology to extend the operating bandwidth, it is a good approach to aggregate the fragmented frequency bands in order to overcome the limitation of spectrum resource in lower frequency bands. In particular, the limited and fragmented spectrum can be combined as one integrated-wider spectrum band by utilizing carrier aggregation technology. However carrier aggregation technology would bring inefficiency on the implementation side. In more detail, a switch in circuit for carrier aggregation has a loss about 1 dB/1 switch. Also carrier aggregation might require Multi Mode & Multi Band (MMMB) power amplifiers to implement the technology; this is inefficient in its performance and more expensive with respect to the component which is dedicated to a single band.
Taking the above arguments into account, the use of higher frequency bands makes it practical to implement higher order antenna arrays and to utilize full dimensional MIMO technologies with reasonable hardware form factors. Also large chunk contiguous bandwidth in these higher frequency bands can be considered for IMT implementation.Traditionally the use of very high frequencies (e.g. millimeter wave bands) for mobile use is considered difficult. In particular, because of the laws of propagation, higher frequencies will result in higher propagation losses between transmitters and receivers. Moreover, it is considered that signals at higher frequencies may not reach the user under NLoS conditions due to a low diffraction effect. However ITU-R WP 5D contribution 5D/258 showed the measurement campaign of propagation loss in several different environments. It shows that high frequency bands operation is feasible for mobile broadband access, for distances over 200 meters even in outdoor NLoS environments.
In addition, it is expected that higher frequencies with wider spectrum bandwidths (e.g., in bands from around 10 to 40GHz) can be used overlaid with existing IMT networks in order to fulfill extremely high user traffic demands in specific areas orat specific times. As a potential deployment scenario, in that case bands below 6GHz can be utilized for high mobility and large coverage data services, meanwhile bands above 6GHz can be reserved for ultra high data rate services.
It is noted that Working Party 5D also emphasized that “no single frequency range satisfies all the criteria required to deploy IMT systems, particularly in countries with diverse geography and population density; therefore, to meet the capacity and coverage requirements of IMT systems multiple frequency ranges would be needed. In addition, it is important to note that the categories of coverage, capacity, and performance are not distinct and can overlap.”
Considering from a variety of views, therefore, higher frequency bands for IMT should be taken into account as one of suitable frequency ranges within APG because higher frequency bands are quite feasible for mobile broadband access.
5. Preliminary Views
The Republic of Korea proposes the candidate bands: 698-790 MHz, 1452-1492 MHz, 3 600-4 200 MHz, 4800-4 900 MHz, 13.4-14 GHz, 18.1-18.6 GHz, 27.029.5 GHz and 38.0-39.5 GHz.The Republic of Korea also proposes the guidelines for discussion of candidate frequency bands within APG.
-Multiple frequency ranges would be needed tosatisfy all the criteria required to deploy IMT systems, particularly in countries with diverse geography and population density.
-Wider contiguous bandwidths should be considered to provide higher performance and to achieve global harmonization.
-Future technology trends should be considered taking into account more than ten years of the implementation time of new spectrum after WRC-15.
-Global allocation to mobile service should be considered in all three Regions on a primary basis.However, frequency bands allocated in one or two Regions or allocated in some countries to the mobile service couldalso be considered.
-Compatibility with incumbent systems should be considered, e.g., protection of passive services stated in the Radio Regulations (e.g., Nos.5.149 and 5.340 for radio astronomy) and Plan bands for satellite services in Appendices 30A and 30B.
Agenda item 1.2: to examine the results of ITU-R studies, in accordance with Resolution 232 (WRC-12), on the use of the frequency band 694-790 MHz by the mobile, except aeronautical mobile, service in Region 1 and take the appropriate measures;
Resolution 232 (WRC-12)–Use of frequency band 694-790 MHz by the mobile, except aeronautical mobile, service in Region 1 and related studies
1. Background
The 700 MHz frequency band allows cost effective implementation of IMT for countries in particular those with large areas and with low population density. At WRC-07, the band 790-862 MHz in Region 1 and some parts of 698-960 MHz in Region 2 were allocated to mobile service on a primary basis. In Region 3 the band 698-790 MHz has been allocated to mobile services on a primary basis and this band was identified to IMT in some countries in Region 3 (see RR No. 5.313A).
There is a need, in many developing countries and countries with large areas of low population density, for the cost-effective implementation of IMT, and that the propagation characteristics of frequency bands below 1GHz identified in Nos.5.286AA and 5.317A result in larger cells. WRC-15 Agenda Item 1.2 was adopted to examine the use of mobile service in the band 694-790 MHz in Region 1 in accordance with Resolution 232 (WRC-12),which invites ITU-R studies on the spectrum requirement for the mobile service and for the broadcasting service in this frequency band, channelling arrangements for the mobile service,adapted to the frequency band below 790MHz, and coexistence between the different channelling arrangements implemented in Region1 above 790MHz, as well as the possibility of further harmonization. It is noted that channelling arrangements for the mobile service should take into account:
-the existing arrangements in Region 1 in the bands between 790 and 862MHz and defined in the last version of Recommendation ITU-R M.1036, in order to ensure coexistence with the networks operated in the new allocation and the operational networks in the band 790-862MHz,
-the desire for harmonization with arrangements across all Regions,
-the compatibility with other primary services to which the band is allocated, including in adjacent bands.
The harmonized channelling arrangements in the band 698-806 MHz was developed by APT and included in the Recommendation ITU-R M.1036 as well as channelling arrangements in Region 1 in the band 806-960 MHz.
2. Preliminary Views
The Republic of Korea supports ITU-R studies to achieve the global harmonized use of IMTconsidering that IMT systems are intended to provide telecommunication services on a worldwide basis, regardless of location, network or terminal used. APT Members recognize that WRC-15 Agenda Item 1.2 is related to the use of mobile service in Region 1, as addressed in this agenda item and Resolution 232 (WRC-12),and should focus on the view to global harmonization taking into account channelling arrangements in the band 698-806 MHz developed by APT in Recommendation ITU-R M.1036.
The Republic of Korea has also a preliminary view that any study result and any decision under this agenda item should not impose undue constraint on the use of mobile services including IMT in Region 3 in the band 698 – 790 MHz.
Agenda item 1.3: to review and revise Resolution 646 (Rev.WRC-12) for broadband public protection and disaster relief (PPDR), in accordance with Resolution 648 (WRC-12);