White Paper on Spectrum

Whitepaper on Spectrum February 2013

Contents Introduction�� 1 Executive summary�� 2 List of abbreviations�� 3 1. Background�� 5 1.1 Economic benefits of IMT�� 5 1.2 Importance of coordinating framework�� 5

2. The need for spectrum�� 6 2.1 Spectrum requirement�� 6 2.2 Service development prediction�� 7 2.3 Spectrum prediction and gap�� 9 2.3.1 Administrators�� 9 2.3.2 Operators�� 9

2.4 Conclusion��11

3. Spectrum map�� 12 3.1 Existing spectrum��12 3.2 Future outlook��14 3.2.1 Analysis on additional frequency bands�� 14 3.2.2 Views on additional frequency bands�� 16 3.2.3 Detailed band-by-band analysis and position�� 16

4. Spectrum utilization & harmonization�� 24 4.1 Global spectrum for small cell�� 24 4.2 SDL (supplemental downlink)�� 25 4.3 LTE carrier aggregation�� 26 4.3.1 CA with same mode�� 26 4.3.2 CA with mixed mode�� 28 4.3.3 Conclusion for CA�� 29

4.4 LTE roaming��30

5. TDD spectrum application�� 32 5.1 TDD spectrum�� 32

5.2 TDD synchronization�� 34

6. Annex�� 36 6.1 Coordinating framework�� 36

7. References�� 40

Introduction Why Spectrum Matters Society benefits from connecting devices over the air at radio frequency spectrum. The mobile industry is increasing rapidly, and this is having a direct benefit on people’s lives and on economic development. Spectrum is a scarce non-renewable resource that is the basis of a mobile communication network. With the arrival of the mobile internet, the requirement for spectrum is increasing exponentially. How to manage spectrum responsibly, how to allocate spectrum efficiently and rationally and how to improve spectrum utilization are critical questions for government, regulator, operators and manufacturers.

About this Whitepaper “Governments need to raise broadband to the top of the development agenda, so that rollout is accelerated and the benefits are brought to as many people as possible” ——----ITU Secretary General, Hamadoun Toure This Whitepaper contains the considerations of Huawei on the spectrum for mobile communication. Capacity demands on mobile wireless networks are increasing at an explosive rate, which has led to the demand for spectrum increasing rapidly as well. A prediction of the necessary spectrum in 2020 based on these requirements, as well as the suggested spectrum for WRC-15, is provided in the first part of this paper. In the following part, the existing operating bands being studied by 3GPP, and spectrum for IMT that could possibly be allocated in the future, are summarized and analyzed to give a full picture of the spectrum available, or that could be made available, for the mobile wireless industry. Specific spectrum suggested for WRC15 includes parts of 470-694 MHz, 694-790 MHz, parts of L band, the band around 2GHz, parts of 3600-4200MHz and 4400-4990MHz. Besides acquiring new spectrum for IMT, the efficient use of existing spectrum is another way to promote the development of the wireless industry. Small cell deployments and the allocation of appropriate high-frequency spectrum for hotspot applications, supplementary downlink spectrum, carrier aggregation and LTE roaming bands as methods to utilize spectrum better are analysed in Section 3. The final subject we emphasize in the Whitepaper is TDD spectrum. Flexible utilization of fragmented spectrum is one advantage of using TDD. Synchronization among different operators is a key issue for TDD systems that is also analysed in the paper. 1

Executive Summary Identify at least 500MHz (in the 400MHz – 6GHz range) at WRC-15 •• Targeting global harmonization to the benefit of economies of scale •• Targeting assignments of at least 100MHcontiguous bandwidth for IMT •• Driven by the well recognized socio-economic value of the mobile broadband application •• Administrations need to take efforts in reducing the time that is currently separating the ITU-R identification from the actual spectrum assignments at national level •• 3.5GHz(3400-3600) as one of the important bands of global spectrum for small cell enhancement

Spectrum efficiently utilized: •• based on CA solution, and mixed TDD+FDD CA as one of future trends •• Candidate bands combination for LTE FDD terminal roaming at least include 1800MHz, E850MHz, APT700MHz and US 700MHz •• Inter-operators’ network synchronization based on over-the-air solution proposed for TDD networks Possible candidate band for IMT under WRC-15 Agenda Item 1.1 Description

Low candidate bands (<1GHz)

Low-to-mid candidate bands (1GHz3GHz)

Mid-to-high candidate bands (3GHz6GHz)

Spectrum

Incumbent user

Parts of 500-600MHz [470-around 694MHz]

TV PMSE

WRC-15 regional identification for IMT usage Need cooperation with Broadcasting industry

700MHz [694-790MHz]

TV PMSE

WRC-15 Regional IMT identification: Region 1 (AI 1.2)

WRC-15 target

Parts of 1.4 GHz [1350-1525MHz]

D-Radio Fixed Link Scientific

WRC-15 global identification for IMT usage Scientific use, only in a part of frequencies and some parts of regions

2700-2900 MHz

Radar

WRC-15 global identification for IMT usage

3.4-3.6 GHz

IMT (In some countries) Sat.


3.6-3.8 GHz

IMT Sat.


Parts of 3.8-4.2GHz

Sat.


Parts of 4.4-4.99 GHz

Sat.


2

List of abbreviations Abbreviations

3

Full spelling

3GPP

3rd Generation Partnership Project

APT

Asia Pacific Telecommunity

ARNS

Aeronautical Radio Navigation Service

ASMG

Arab Spectrum Management Group

ATU

African Telecommunications Union

BSS

Base Station Subsystem

BWA

Broadband Wireless Access

CA

Carrier Aggregation

CEPT

European Conference of Postal and Telecommunications Administrations

CITEL

Inter-American Telecommunications Commission

CJK

China Japan Korea

CR

Cognitive Radio

D2D

Device-to-Device

DAB

Digital Audio Broadcasting

DAS

Distributed Antenna System

DCS

Digital Cellular System

eMBMS

enhanced Multimedia Broadcast/Multicast Service

EVM

Error Vector Magnitude

FCC

Federal Communications Commission

FDD

Frequency Division Duplexing

FSS

Fixed Satellite Service

GPS

Global Positioning System

GSM

Global System for Mobile communications

IMT

International Mobile Telecommunications

ITU

International Telecommunication Union

ITU-R

International Telecommunication Union Radiocommunication Sector

LTE

Long Term Evolution

LTE-Hi

LTE Hotspot & Indoor Enhancement

M2M

Machine-to-Machine

Abbreviations

Full spelling

MCS

Mobile Communication Service

MFCN

Mobile/Fixed Communications Networks

MIIT

Ministry of Industry and Information Technology of China

MSS

Mobile-Satellite Service

PCS

Personal Communications Service

PMSE

Programme Making and Special Events

RCC

Regional Commonwealth in the field of Communications

RSGB

Radio Society of Great Britain

SDL

Supplemental DownLink

TDD

Time Division Duplexing

UMTS

Universal Mobile Telecommunications System

WCS

Wireless Communications Service

WLAN

Wireless Local Area Networks

WRC

World Radiocommunication Conference

WP5D

Working Party 5D

4

1 Background 1.1 Economic benefits of IMT1 Mobile broadband systems, especially IMT, contribute to global economic and social development by providing a wide range of multimedia applications, such as mobile telemedicine, teleworking, distance learning and other applications. IMT is the root name, encompassing both IMT-2000 and IMT-Advanced. IMT systems are intended to provide telecommunication services on a worldwide scale, regardless of location, network or terminal used. IMT systems have been the main method of delivering wide area mobile broadband applications. In all countries where IMT systems are deployed there is a continuing significant growth in the number of users of IMT systems and in the quantity and rate of data carried, the latter being driven to a large extent by audiovisual content. This economic success is built on IMT-2000, but future economic welfare will depend upon the growth of new technologies, such as IMT-Advanced and so on. Any regulatory changes or uncertainty that jeopardizes those needs should be considered very carefully. As the European Commission Communication on radio spectrum policy2 notes, “The EU’s timely provision of harmonized frequencies “triggered” the development of new pan-European digital cellular system (GSM)”.

1.2 Importance of coordinating framework Adequate and timely availability of spectrum and supporting regulatory provisions is essential to support future growth of IMT systems. Many countries have not yet made available spectrum already identified in the Radio Regulations for IMT, for various reasons, including the use of this spectrum by other systems and services. The coordinating framework of the international use of the radio spectrum showed in Annex of this whitepaper is functioning effectively to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum in each country of the world. For example, frequency-related matters for IMT in certain frequency bands below 6 GHz were studied in preparation for WRC-07, and WRC-07 decided upon technical conditions and regulatory procedures in some of these bands.

5

1

From "Optimising spectrum for future mobile service needs"(GSMA, 2006) and "Studies on frequency-related matters on International Mobile Telecommunications and other terrestrial mobile broadband applications" (RESOLUTION 233-WRC-12, 2012)

2

Brussels, 6.2005 COM(2005) 411 final

There is a fairly long lead time between the identification of frequency bands by world radiocommunication conferences and the deployment of systems in those bands, and timely availability of spectrum is therefore important to support the development of IMT systems. The coordinating framework will continue to assure the timely availability of spectrum for IMT in the world.

2 The need for spectrum 2.1 Spectrum requirement It takes a number of years for spectrum to be allocated and identified at ITU level and then assigned at national level until it is finally deployed in the network, so we have to start planning the spectrum for IMT in the year 2020 now. Following the practice laid down at WRC-07, spectrum requirement estimation should be done as first step to provide the motivation for the IMT industry to argue for more spectrum allocation to mobile services and more spectrum identification to IMT services in particular. Figure 1 shows the comparison between the estimated required, ITU identified and regionally available spectrum. Estimated spectrum requirement by year in MHz

1720

Current available spectrum by region in MHz

Global identified IMT spectrum in MHz 1172

1300 840

630

590 478

360

TE

L(L

A)

A) L(N TE CI

PT CE

AT U

G M AS

T AP

ide

nt ifie d

10 20

15 20

20

20

370

CI

510

Figure 1 Comparison of the amount of the estimated required, global identified and regional available spectrum (source: ITU-R M.2078 & UMTS Jan. 2012)

6

Because of difficulties experienced by each nation in allocating spectrum, only around half of the already identified spectrum is available. As user demand outpaces advances in technology and deployment, the operators will have to control the traffic increase by their pricing plans. During the preparation for WRC-15, spectrum requirement estimation is ongoing in ITU Working Party 5D3. The estimated requirement is in total around 1800MHz4 (using the higher requirements setting). Compared with the 1172MHz already identified, it is clear that more than 500MHz of additional spectrum is needed.

2.2 Service development prediction With the fast advance of the mobile Internet, mobile data traffic has dramatically increased. According to the mobile global data traffic estimates summarize in ITU M.24435, overall mobile data traffic averagely grow 8 times in 2015 over 2011. Visioning the future year 2020, the traffic is 500-1000 times today’s traffic, driven by the demand for mobile broadband for anything, anytime from anywhere. Figure 2 from the CJK WhitePaper6 summarized the major driving forces for the traffic explosion.

Smartphones, tables, laptops and netbooks Improved user experience: user friendly interfaces, lager screen size and longer battery life

New mobile app. supporting social live and production; Online stores of mobile-Apps

Increased demand for mobile video services

Mobile video

New type of device

Flat rate User experience

Price decrease

Dramatic growth of mobile data traffic

New mobile app

Connection to Internet

Mobile: the main / sole way to visit Internet for many people

Convergence Convergence of mobile communication and other industries

Figure 2 Drivers of mobile date traffic increase

7

3

http://www.itu.int/ITU-R/index.asp?category=study-groups&rlink=rwp5d&lang=en

4

“Draft Liaison statement to Joint Task Group 4 5-6-7 - Initial information on spectrum requirements studies for WRC-15 Agenda item 1.1”, http://www.itu.int/md/R12-JTG4567-C-0047/en

5

ITU-R M.2243(00/2011), http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2243-2011-PDF-E.pdf

6

“CJK WhitePaper on Forecast of mobile broadband development in the Asia-Pacific Region”, http://www.tta.or.kr/English/new/external_relations/meetingDocumentView. jsp?boardIdx=IMT&num=109

The explosively increasing mobile traffic is not distributed evenly over the whole network and more than 80% of the traffic comes from hotspots or indoor areas, based on the analysis from Informa Telecoms & Media7. It is also forecasted that mobile video will be the dominant service in the near future and it is shown that about 70% of mobile services will be video in 2016 based on the prediction of mobile traffic share from Cisco8. To meet the explosive traffic demands and higher performance expectation, the heterogeneous network or HetNet is becoming the network topology of the future, as shown in Figure 3. The service of the small cells is compatible with a good fixed network (fiber …). If the data speed of the fixed network is too slow, or if there is not fixed network, the traffic will be captured by large cells. Public fixed networks provide, more and more, the TV services (Broadcast TV, TV on demand…). The future evolutions of the mobile network will be probably similar, and, the impact of this evolution will be to create the traffic asymmetry (more downlink traffic than the uplink traffic).

Figure 3 Heterogeneous Network

One way to map the spectrum frequency to the deployment scenario is as below: 111 Wideband for the capacity. It is easier to find wideband in high spectrum (above 1GHz or 3GHz). 222 The propagation and the coverage is better at low frequency (below 3GHz and especially below 1GHz) 333 Below 400MHz, there are some technical difficulties to design the mobile terminal As mobile traffic increases and mobile connection speeds increase for anything, anytime from anywhere, more spectrum in the low and low-to-mid bands is needed to provide the coverage and capacity. The mid-to-high band is much more important than ever before, to provide high performance, and also to provide capacity boosting for the urban environment, especially hotspot and indoor areas.

7

Mobile broadband access at home: Informa Telecoms & Media

8

Cisco, Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, 2011-2016, http://www.cisco.com/en/US/solutions/collateral/ns341/ns525/ns537/ns705/ns827/white_ paper_c11-520862.html

8

2.3 Spectrum prediction and gap 2.3.1 Administrators All administrators are facing the prospect of a spectrum shortage, some examples are shown in Table 1. Table 1 Spectrum requirements forecast by administrators.

Administrator

Information Source

Europe

EuropeanUnion Radio Spectrum Policy Programme (RSPP)

USA

FCC National Broadband Plan

Traffic increase forecast

Baseline bandwidth for IMT

Additional Spectrum Requirement

Y2015:1200MHz

35 times increase in traffic from 2009 to 2014

Canada

Global Mobile Broadband Forum 2012

Australia

ACMA paper Towards 2020 – Future spectrum requirements for mobile broadband

30 times increase in traffic from 2007 to 2014

Japan

AWG workshop for future IMT (AWG-13/INP136)

Growth rate of traffic is increasing to more than 100% per year.

China

ITU-R WP5D#15 (document 5D/256)

Around 600times increase in traffic from 2010 to 2020

Y2009 allocated: 547MHz

Y2014: 300MHz for mobile broadband Y2020: 500MHz for mobile and fixed broadband


Y2015:300500MHz Y2022:400600MHz

Y2012 allocated and planned: 840MHz

Y2015: 150MHz Y2020: 300MHz


690MHz

Y2015: over 300MHz Year 2020: total over 1000MHz Y2020:8001100MHz

As we can see, the amount of global identified spectrum is twice the amount of regionally available spectrum, because each nation has its own limitations on spectrum arrangements and the difficulty of establishing global harmonized spectrum.

2.3.2 Operators From the business perspective, there is never sufficient spectrum, and operators will have to ease the traffic increase by pricing. In the case of AT&T, iPhone users were to be provided unlimited traffic contracts, but the traffic explosion quickly congested the network and AT&T had to gradually move unlimited data plans to 9

tiered mobile data packages to ease the traffic increase and to keep the network balanced. In this sense, we could say that even facing today’s traffic explosion, the spectrum is not enough, let alone for the year 2020. AT&T, for example, has stated9 that growth rate and data demand outpaces the capabilities of these advanced radio interface technologies and network topographies. Future new spectrum allocation to IMT is required as user demand outpaces the technology and deployment advances. What AT&T has faced is not unique among operators in the United States or elsewhere in the world. The licensed spectrums the Japan’s operators hold are shown in Table 2. Considering the low band and low-to-mid band, it seems the main operators hold sufficient amount of resource, although the amount of efficient spectrum held is far less than the total amount held by operators as shown in Table3. Japan’s 3.5G work is ongoing, which is supposed to provide large capacity and high performance. Wi-Fi has been used for offloading traffic to alleviate the operators’ pressure on network capacity; while IMT small cell technology in higher band is targeted to carry and control the traffic on licensed spectrum when the spectrum becomes available, which DOCOMO is also actively research and promoting. Table 2 Spectrum held by licensed spectrum operators in Japan10 700MHz bands

800MHz bands

900MHz bands

1.5GHz bands

1.7GHz bands

2GHz bands

2.5GHz bands

ToTal

DoCoMo

20MHz

30MHz

-

30MHz [Partially limited]

40MHz [Only in some areas]

40MHz

-

160MHz

AU

20MHz

30MHz

-

20MHz

-

40MHz

-

110MHz

Softbank

-

-

30MHz

20MHz

-

40MHz

-

90MHz

E-Access

20MHz

-

-

-

30MHz

-

-

50MHz

UQ

-

-

-

-

30MHz

30MHz

Wireless City Planning

-

-

-

-

-

30MHz

30MHz

-

31.2MHz [Partially share with codeless phone]

-

31.2MHz

WILLCOM

-

-

-

-

-

9

“Addressing spectrum efficiency, information on current and planned use, and technical and operational characteristics in frequency bands for IMT under WRC-15 Agenda item 1.1”, AT&T, http://www.itu.int/md/R12-WP5D-C-0179/en

10

“Frequency Management Policy on Mobile Communications in Japan”, Japan, http://www.apt.int/sites/default/files/2012/09/AWG-13-INP-136_Japan_MIC_presentation_in_AWG_Workshop.pdf

10

Table 3 bands from global harmonization perspective held by Japanese operators 700M

800M

900M

1.5G

1.7G

2GHz

2.5GHz

DoCoMo

20MHz

40MHz

60MHz

AU

20MHz

40MHz

60MHz

40MHz

70MHz

Softbank E-Access

30MHz 20MHz

UQ

20MHz 30MHz

2.4 Conclusion As is being discussed in ITU-R WP5D, more than 500MHz of additional spectrum is needed for the year 2020, distributed in three band ranges – low band (<1GHz), mid-to-high band (1-3GHz) and high band (3-6GHz), to support the explosive traffic increase and higher performance expectation.

11

Total

30MHz

3 Spectrum map 3.1 Existing spectrum The map below shows a summary of the worldwide frequency allocation in the bands from 300MHz to 30GHz.

Figure 4 Summary frequency allocation from 300MHz to 30GHz

The following map shows the main IMT bands allocated in each ITU region.

IMT Spectrum Map Region 1

Region 2

FDD

FDD

•• Band 1 (2100M) •• Band 3 (1800M) •• Band 7 (2.6G) •• Band 8 (900M) •• Band 20 (DD800) •• Band 22 (3.5G)

•• Band 2 (1900M) •• Band 4 (AWS) •• Band 5 (850M) •• Band 10 •• Band 12 (700M L) •• Band 13 (700M U) •• Band 14 (700M) •• Band 17 (700M) •• Band 23 (MSS) •• Band 24 (L-band) •• Band 25 (E1900) •• Band 26 (E850 U) •• Band 27 (E850 L) •• Band 28 (APT700) •• Band 29 (DL 700)

TDD •• Band 33 •• Band 38 (2.6G) •• Band 42 (3.5G) •• Band 43 (3.6G)

Region 3

Region 3(Japan Specific)

FDD

TDD

FDD

•• Band 1 (2100M) •• Band 3 (1800M) •• Band 5 (850M) •• Band 8 (900M) •• Band 28 (APT700)

•• Band 34/a •• Band 39/f •• Band 40 (3.5G) •• Band 28 (3.6G) •• Band 44 (APT700)

•• Band 1 (2100M) •• Band 6 (850M) •• Band 9 (1800M) •• Band 11

•• Band 18 (850M) •• Band 19 (850M) •• Band 21 (1.5G)

TDD •• Band 41 (2.6G)

Figure 5 IMT global spectrum distribution (existing situation) 12

3GPP already defined the band number for different regional allocation. Table 4 Existing spectrum for IMT in 3GPP MSR/E UTRA Band number

13

UTRA Band number

Uplink (UL) BS receive UE transmit

GSM/ EDGE Band designation

FUL_low

– –

1

I

-

1920 MHz

2

II

PCS 1900

1850 MHz

3

III

DCS 1800

1710 MHz

4

IV

-

1710 MHz

5

V

GSM 850

6(1)

VI

Downlink (DL) BS transmit UE receive

FUL_high

FDL_low

–

FDL_high

Dup Mode

1980 MHz

2110 MHz

–

2170 MHz

FDD

1910 MHz

1930 MHz

–

1990 MHz

FDD

–

1785 MHz

1805 MHz

–

1880 MHz

FDD

–

1755 MHz

2110 MHz

–

2155 MHz

FDD

824 MHz

–

849 MHz

869 MHz

–

894MHz

FDD

-

830 MHz

–

840 MHz

875 MHz

–

885 MHz

FDD

7

VII

-

2500 MHz

–

2570 MHz

2620 MHz

–

2690 MHz

FDD

8

VIII

E-GSM

880 MHz

–

915 MHz

925 MHz

–

960 MHz

FDD

9

IX

-

1749.9 MHz

–

1784.9 MHz

1844.9 MHz

–

1879.9 MHz

FDD

10

X

-

1710 MHz

–

1770 MHz

2110 MHz

–

2170 MHz

FDD

11

XI

-

1427.9 MHz

–

1447.9 MHz

1475.9 MHz

–

1495.9 MHz

FDD

12

XII

-

699 MHz

–

716 MHz

729 MHz

–

746 MHz

FDD

13

XIII

-

777 MHz

–

787 MHz

746 MHz

–

756 MHz

FDD

14

XIV

-

788 MHz

–

798 MHz

758 MHz

–

768 MHz

FDD

15

XV

-

Reserved

Reserved

16

XVI

-

Reserved

Reserved

17

-

-

704 MHz

–

716 MHz

734 MHz

–

746 MHz

FDD

18

-

-

815 MHz

–

830 MHz

860 MHz

–

875 MHz

FDD

19

XIX

-

830 MHz

–

845 MHz

875 MHz

–

890 MHz

FDD

20

XX

-

832 MHz

–

862 MHz

791 MHz

–

821 MHz

FDD

21

XXI

-

1447.9 MHz

–

1462.9 MHz

1495.9 MHz

–

1510.9 MHz

FDD

22

XXII

-

3410 MHz

–

3490 MHz

3510 MHz

–

3590 MHz

FDD

23

-

-

2000 MHz

–

2020 MHz

2180 MHz

–

2200 MHz

FDD

24

-

-

1626.5 MHz

–

1660.5 MHz

1525 MHz

–

1559 MHz

FDD

25

XXV

-

1850 MHz

–

1915 MHz

1930 MHz

–

1995 MHz

FDD

26

XXVI

-

814 MHz

–

849 MHz

859 MHz

–

894 MHz

FDD

27

-

-

807 MHz

–

824 MHz

852 MHz

–

869 MHz

FDD

28

-

-

703 MHz

–

748 MHz

758 MHz

–

803 MHz

FDD

29

-

-

–

–

–

717 MHz

–

728 MHz

FDD

33

a)

1900 MHz

–

1920 MHz

1900 MHz

–

1920 MHz

TDD

34

a)

2010 MHz

–

2025 MHz

2010 MHz

–

2025 MHz

TDD

35

b)

1850 MHz

–

1910 MHz

1850 MHz

–

1910 MHz

TDD

36

b)

1930 MHz

–

1990 MHz

1930 MHz

–

1990 MHz

TDD

37

c)

1910 MHz

–

1930 MHz

1910 MHz

–

1930 MHz

TDD

38

d)

2570 MHz

–

2620 MHz

2570 MHz

–

2620 MHz

TDD

39

f)

1880 MHz

–

1920 MHz

1880 MHz

–

1920 MHz

TDD

40

e)

2300 MHz

–

2400 MHz

2300 MHz

–

2400 MHz

TDD

41

-

2496 MHz

–

2690 MHz

2496 MHz

–

2690 MHz

TDD

42

-

3400 MHz

–

3600 MHz

3400 MHz

–

3600 MHz

TDD

43

-

3600 MHz

–

3800 MHz

3600 MHz

–

3800 MHz

TDD

44

-

703 MHz

–

803 MHz

703 MHz

–

803 MHz

TDD

3.2 Future outlook The International Telecommunication Union Radiocommunication Sector (ITU-R) is responsible for coordinating the international use of the radio spectrum and holds World Radiocommunication Conferences (WRC) every three to four years to review and revise the Radio Regulations, the international treaty governing the use of radio-frequency spectrum, geostationary-satellite and non-geostationarysatellite orbits. The activities related to spectrum for IMT at WRC are as follows.

1990

2000

2010

2020

WARC-92(1992) WRC-2000(2000)

Identified spectrum for IMT-2000

WRC-07(2007)

Identified additional spectrum for IMT-2000

WRC-15(2015)

Identified spectrum for IMT (including IMT-2000 and IMT-Advanced)

To consider the need and identification for additional spectrum for IMT

Figure 6 activities related to spectrum for IMT at WRC

The agenda items of WRC-15 dealing with spectrum matters for IMT are:

WRC-15 AI 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);

WRC-15 AI 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;

Figure 7 Agenda items of WRC-15 dealing with spectrum matters for IMT

3.2.1 Analysis on additional frequency bands Taking into account specific characteristics of different bands and the logical mapping from the three types of frequency band mentioned above to suitable frequency ranges of IMT, there are some specific requirements and considerations on the different frequency ranges and possible bandwidths, when additional frequency bands for IMT are under discussion, which will happen under Agenda Items 1.1 and 1.2 of WRC-15. 14

Firstly, where cost considerations require the installation of fewer base stations, not only in rural and/or sparsely populated areas but also in urban and/or suburban areas, bands with good coverage to facilitate such deployment are generally suitable for implementing mobile systems, including IMT. Especially in many developing countries and countries with large areas of low population density, there is a need for cost-effective implementation of IMT. In fact, lower frequency bands(< 1 GHz) are most suitable for providing coverage with low cost based on the propagation characteristics. Firstly bis, to grow the current IMT frequency bands. Secondly, Report ITU-R M.2074 identifies the preferred frequency ranges for the future development of IMT-2000 and IMT-Advanced, including both the “new mobile access” and “new nomadic/local area wireless access” as they are presented in Recommendation ITU-R M.1645. It suggests that new spectrum that can fulfill the full range of requirements of the ITU for IMT-Advanced, should be found below 6 GHz for a number of technical reasons, such as allowing sufficient mobility, an acceptable trade-off between cost and full area coverage, availability of the required RF hardware components and mobile terminal complexity and power consumption. Concretely, the frequency bands from 1GHz to 6GHz, including Low-to-mid bands (1-3GHz) and Mid-to-high bands (3-6GHz), are most suitable to provide capacity and performance. Thirdly, further studies are needed to resolve the availability issues for IMT in high bands (>6GHz) because of the different characteristics of spectrum above and below 6GHz. These studies should focus on technical, propagation and implementation aspects of high bands (>6GHz) for IMT. Therefore, it would be better that the frequency bands above 6GHz are considered at WRC-19 rather than WRC-15). Fourthly, as higher and higher bitrates will be demanded for the future development of IMT systems, larger channel bandwidths (continuous or composite by carrier aggregation) will be needed. Report ITU-R M.2074 includes detailed analysis of some of the technical issues surrounding the spectrum range preferences for the future development of IMT-2000 and IMT-Advanced. The Report states that a new radio access system, covering the full range of capabilities of IMT-Advanced is envisaged to support a wide range of data rates according to economic and service demands in multi-user environments. There will be target peak data rates of up to approximately 100 Mbit/s for high mobility and up to approximately 1 Gbit/s for low mobility. It may be possible to reach considerably higher overall spectrum efficiency than today's technologies, but even under the most optimistic assumptions discussed today and in favorable radio reception conditions, the 1 Gbit/s transmission rate may require bandwidth in the order of 100 MHz or more.

15

3.2.2 Views on additional frequency bands We support the identification of additional frequency bands for IMT to facilitate the development of terrestrial mobile broadband applications at WRC-15. At WRC-15, we support making at least 500 MHz of spectrum newly available for IMT by 2020, with up to 1GHz being provided if possible. Based on the above analysis, it is our view that it is not only the amount of spectrum that is important but also the aspects affecting frequency range preferences. These are primarily based on the requirements and target characteristics for the envisioned system of IMT These will have to be considered for frequency ranges to study in relation to WRC-15 Agenda items 1.1 and 1.2. With respect to the preferred frequency ranges for the future development of IMT-2000 and IMT-Advanced, we propose that the new spectrum for IMT should be identified mainly below 6 GHz at WRC-15 due to technical reasons identified in Report ITU-R M.2074. •• Low bands (< 1GHz) – mainly used for macro network to provide coverage •• Low-to-mid bands (1-3GHz) – mainly used for macro and micro network to provide coverage/capacity •• Mid-to-high bands (3-6GHz) – mainly use for micro/pico/hotspots network and Wireless Sensor Networks to provide high capacity and performance.

Meanwhile we think that high bands (>6GHz) should be considered at the next WRC(WRC-19), rather the upcoming WRC-15, because of larger different frequency characteristics. Larger bandwidths for the future development of IMT will be needed, such as 100 MHz or more (preferred continuous bands).

3.2.3 Detailed band-by-band analysis and position For WRC-07, a set of candidate bands for IMT were proposed, with the support of Administrations and those proposals should be taken into account as IMT candidate in WRC-15. Candidate frequency ranges available for identifying spectrum for the terrestrial component of future development of IMT-2000 and IMT-Advanced in the Report ITU-R M.2024 and M.2079 include 410-430 MHz, 470-790 MHz, 2 700-2 900 MHz, 3 600-4 200 MHz, 4 400-4 990 MHz. Furthermore we support to consider, TV UHF band (470-694MHz), L band (a part of 1300-1900 MHz), C Band(3.4-3.8-4.2GHz) as possible candidate bands for IMT under WRC-15 AI1.1 based on our studies. 16

Finally our band-by-band analysis and position of some possible candidate bands for IMT are as follows.

Table 5 Possible candidate band for IMT under WRC-15 Agenda Item 1.1 Description

Low candidate bands (<1GHz)

Low-to-mid candidate bands (1GHz3GHz)

Mid-to-high candidate bands (3GHz6GHz)

Spectrum

Incumbent user

Parts of 500-600MHz [470-around 694MHz]

TV PMSE

WRC-15 regional identification for IMT usage Need cooperation with Broadcasting industry

700MHz [694-790MHz]

TV PMSE

WRC-15 Regional IMT identification: Region 1 (AI 1.2)

WRC-15 target

Parts of 1.4 GHz [1350-1525MHz]

D-Radio Fixed Link Scientific

WRC-15 global identification for IMT usage Scientific use, only in a part of frequencies and some parts of regions

2700-2900 MHz

Radar


3.4-3.6 GHz

IMT (In some countries) Sat.


3.6-3.8 GHz

IMT Sat.


Parts of 3.8-4.2GHz

Sat.


Parts of 4.4-4.99 GHz

Sat.


[1] 470-694 MHz WHY THE BAND This band 470-694/698MHz provides great propagation characteristics for coverage and indoor penetration. This band is also adjacent to the bands on which IMT systems are deployed i.e. 450-470MHz and 698/694-960MHz, which reuse of the existing RF components is possible. For the time being, the band is widely usually used for broadcasting service, but parts of this band are also considered for mobile broadband under national broadband plans globally. Along with the progress of broadcasting analogue-to-digital switch over, and the finalization of band clearing of 700MHz and 800MHz, this band 470-694/698 is to be considered as potential candidate bands for IMT, which is now discussed in ITU-R. Part of this band is now discussed in the United States in the content of “incentive auction”.

SPECTRUM DEVELOPMENT PATH Given its contiguity with the existing IMT bands, i.e. 450-470MHz and 698/694960MHz, the frequency arrangement and development path should closely 17

follow the decisions that have been previously taken in such bands, where exclusive individual usage rights are being assigned. Global harmonization should be addressed from the very beginning. Synergies with the adjacent bands shall be exploited: base station and user device RF components (e.g. amplifiers and antennas may be reused to a large extent). .

CONCLUSIONS It’s proposed to identify 470-694/698MHz or part of this band for IMT at WRC-15 to provide cellular coverage network.

[2] 694-790 MHz WHY THE BAND Band 694-790MHz is also of high value due to its excellent propagation characteristics. The band is currently widely used for broadcasting service and also ARNS (Aeronautical Radio Navigation Systems). The advent of the digital TV technology and consequent switch off of the less spectrally efficient analog TV technology has led to a ”Digital Dividend” which is allowing to make the band available for IMT applications.

SPECTRUM DEVELOPMENT PATH In Region 1, the band 700MHz is decided to allocate by WRC-15. Now some preparation works are planned to be done. The target is to allocate the frequency band 694-790 MHz in Region 1 to the mobile for IMT; then the allocation is effective immediately after WRC 15. In Region 2, the band is identified for IMT, spectrum has been assigned as FDD as shown in the diagram below. MHz 690

700

710

A4

720

MS Tx 698

730

un-paired 716

728

740

750

BS Tx

760

770

780

790

BS Tx 746

800

810

MS Tx 763

776

793 M.1036-03-A4

Figure 8 P694-790 MHz frequency arrangement of Region 2

11

11

From ITU-R M.1036-4

18

In region 3, at the meeting of the APT Wireless Forum (AWF-9) at Sep.,2010, agreement was reached on two harmonized frequency arrangements for IMT in 698-806MHz frequency band. It was decided that spectrum should be allocated as follows: For FDD: •• a lower guard-band of 5 MHz should be allocated between 698-703 MHz; •• an upper guard-band of 3 MHz should be allocated between 803-806 MHz. For TDD: •• Whole Bands from 698MHz to 806MHz for TDD The band plan is not compatible with FDD band Plan. Actually, South America is gradually following the APT band plan (FDD).

10 MHz centre gap

5 MHz

45 MHz

DTTV

DTTV

3 MHz

45 MHz

694 6 9 8 MHz MHz

PPDR/LMR

806 MHz

Figure 9 694-790 MHz frequency arrangement of Region 3 12

CONCLUSIONS Band 700MHz brings a significant amount of “high quality” spectrum for mobile broadband. Commercial networks have already been launched in US, in Region 3 the band had been identified as IMT utilization, in Region 1 the issue will be decided at WRC-15. We propose the harmonization or compatibility usage of the band between Region 1 and Region 3 for economies of scale and effective utilization of the band.

12

19

From ITU-R M.1036-4

PPDR/LMR

[3] L-band (1350-1525 MHz) WHY THE BAND The L-band13 may provide good coverage and may complement below 1 GHz bands which may not be sufficient to address the wider capacity needs. Currently allocated by the ITU Radio Regulations (WRC-12 revision) on a primary and/ or secondary basis to the Mobile Service, Fixed Service, Broadcasting Satellite Service, the band has clear potential for Global/Regional harmonization, with specific reference to the 1427-1525 MHz and/or 1525-1660MHz ranges (excluding the 1400-1427MHz portion).

SPECTRUM DEVELOPMENT PATH 1427.9-1462.9/1475.9-1510.9 MHz bands in Japan have been allocated to LTE in 2011, and the total bandwidth is limited at 2*15MHz or 2*20MHz or 2*34MHz; the harmonization work at European level is ongoing for the Mobile/Fixed Communication Networks (MFCN) supplemental downlink in the 1452-1492 MHz range. Future IMT identification should include the ranges from 1350-1400, 14271525 MHz and possibly from 1525 to 1660 MHz as defined in 3GPP.

1420 1430

Stage 1

RA

Softbank

RA

1420 1430

Stage 3

RA

1450

1460

1470

Softbank

3G

1420 1430

Stage 2

1440

1440

1450

3G

1440

3G

1450

1480

1490

3G MCA

MCA

1460

1470

MCA

MCA

1460

1470 MCA

MCA

Softbank

1480

1490

1500 1510 MCA

3G

1480

1500 1510

1520

1530 [MHz]

Softbank

1490

1500 1510

3G

MCA

1520 MCA

1520 MCA

MSS

1530 [MHz]

MSS

1530 [MHz]

MSS

Figure 10 1427.9-1462.9/1475.9-1510.9 MHz bands in Japan14

13

L-Band terminology refers to the 1 to 2 GHz frequency range, as defined by the Radio Society of Great Britain (RSGB),

14

From Japanese MIC

20

Table 6 1427-1525 & 1525-1660 MHz defined in 3GPP15 E UTRA Operating Band 11

21

24

Uplink (UL) operating band BS receive UE transmit FUL_low 1427.9 MHz 1447.9 MHz 1626.5 MHz

–

FUL_high

–

1447.9 MHz

–

1462.9 MHz

–

1660.5 MHz

Downlink (DL) operating band BS transmit UE receive FDL_low 1475.9 MHz 1495.9 MHz 1525 MHz

Duplex Mode

–

FDL_high

–

1495.9 MHz

FDD

–

1510.9 MHz

FDD

–

1559 MHz

FDD

Although the bands (1350-1525 MHz) are considered as key candidate band for IMT, many efforts are necessary because the band is also the important band for other services and supplications, including GPS and DAB applications. That will be the high priority item in WRC-15.

CONCLUSIONS We propose the global harmonized allocation for IMT in parts of this band at WRC-15. The future use for IMT in this band will contribute to the need of coverage and capacity for the future development of IMT.

[4] Bands around 2GHz(1980-2010 MHz paired with 2170-2200 MHz, 1900-1920/2090-2110 MHz and 2010-2025 /2200-2215 MHz WHY THE BAND The frequency bands 1980-2010 MHz and 2170-2200MHz have already been allocated to IMT-2000 in WARC-92. The bands were assigned for Mobile-Satellite Service (MSS) in EU, Korea, Japan and some other countries with little degree of actual utilization. This band is adjacent to 3GPP Band 1/I. There are some proposals to GSMA and ITU-R that combining the MSS Band, existing 3GPP Band 1/I, TDD Bands 33/34 and the bands 2090-2110 MHz / 2170-2200 MHz can create a contiguous frequency band in some countries, which can help promote the wider availability of mobile broadband. Furthermore they think that 20902110 and 2200-2215 MHz may be paired with existing IMT TDD bands (3GPP TDD Band 33/34) to create new FDD bands in some countries. It may violate the profits of TDD operators.

15

21

From 3GPP

At the same time, we have also taken note that TDD Bands 33/34 are still important TDD band in some other countries who tend to leave the bands as they are.

Band 33

1900MHz

Band 1 UL

1920MHz

MSS

1980MHz

Band 34

2010 2025MHz

1900MHz

2025MHz

Band 1 DL

2090MHz 2110MHz

MSS

2170MHz

2090MHz

2200

2215MHz

2215MHz

Figure 11 A possible combination of bands around 2GHz

CONCLUSIONS We propose the global harmonized allocation for IMT terrestrial components in the band 1980-2010 MHz and 2170-2200MHz at WRC-15. Furthermore there may be two separate side-by-side ways to deal with existing IMT TDD bands (3GPP TDD Band 33/34) in the world. •• The first way is that the allocation of the bands 1900-1920(3GPP TDD Band 33) and 2090-2110MHz, 2010-2025(3GPP TDD Band 34) and 2200-2215 MHz as paired bands for IMT create new FDD bands in one Region or some countries for effective utilization of the band because the bands have been allocated for IMT TDD in those counties, but never used for a long time. •• The second one is still to keep TDD Bands 33/34 as it is now in some other countries because the bands have been allocated and used for IMT TDD in those counties.

[5] 3600-4200 MHz WHY THE BAND In International Telecommunication Union (ITU-R), World Radiocommunication Conference in 2007 (WRC-07) have raised an issue by a number of countries (in particular from Africa) regarding protection of FSS earth stations/VSATs which led to a WRC-15 agenda item about 3400-4200MHz. The band 3400-3800MHz decided for Broadband Wireless Access (BWA) is already widely available for licensing in Europe and have earlier been allocated to the Fixed service on a primary basis in Region 1. The band 3600-4200MHz is to be considered as a key candidate band for IMT for WRC-15 identification.

22

SPECTRUM DEVELOPMENT PATH In EU, CEPT administrations already designated the frequency bands 3400-3800 MHz on a non-exclusive basis to mobile/fixed communications networks (MFCN), without prejudice to the protection and continued operation of other existing users in this band, according to the TDD band plan arrangement. The 600MHz in the 3600-4200 MHz range offer an important opportunity to fulfill the increasing throughput requirement. Located in a higher frequency range, while still below the 6GHz boundary, this range is especially suitable small coverage allowing focused capacity with a higher degree of frequency reuse. However the band is currently heavily used for the FSS service, in larger countries especially where satellite communications offer a cost effective communication mean. Thus, although the band is potentially global harmonized, it is difficult to clear the band in order for IMT utilization in many countries in the next few years.

CONCLUSIONS It’s proposed to identify 3600-3800MHz for IMT to provide cellular network with capacity to fulfill increasing traffic requirement, especially for small coverage with denser cellular. Regarding the bands 3800-4200MHz, the spectrum sharing between IMT and FSS should be advocated with low power IMT network (E.g. LTE-Hi).

[6] 4 400-4 990 MHz WHY THE BAND The band 4400-4990 MHz has propagation characteristics that are suitable for use in dense urban areas where the deployment of mobile networks is typically capacity limited. At the same time, the band can also provide large contiguous bandwidths that can be used for microcell and picocell network to provide increased capacity and performance.

SPECTRUM DEVELOPMENT PATH The band 4400-4990 MHz could support mobile broadband applications with minimal hardware modifications allowing for economies of scale to be met in deployment of new systems and networks. What’s more, RF components, antennas and amplifiers, as well as design solutions, already exist for certain frequencies in 5-6 GHz and are already embedded in user equipment which could be used for IMT implementation. However they have an analogy with the situation on the band 3600-4200MHz. The traditional utilizaion is FSS/ VSATs. The band is currently heavily used for the FSS service, in larger countries especially where satellite communications offer a cost 23

effective communication mean. Thus, it is difficult to clear the band in order for IMT utilization in many countries in the next few years.

CONCLUSIONS It’s proposed to identify 4400-4500MHz and 4800-4990MHz for IMT to provide cellular network with capacity to fulfill increasing traffic requirement, especially for small coverage with denser cellular. Regarding the bands 4500-4800MHz, the spectrum sharing between IMT and FSS should be advocated with low power IMT network (E.g. LTE-Hi: LTE Hotspot & Indoor Enhancement).

4 Spectrum utilization & harmonization Since WRC-92, there are many bands allocated to IMT. How to better use the band is the point of the chapter.

4.1 Global spectrum for small cell It is stated that herein high frequency means the band range from 3GHz to 6GHz. Main usage models for high frequency are listed as following. •• Small cell deployed, •• Relay to connect with VIP customer. •• Mobile Relay. 3.5GHz is one of the most important bands of global spectrum for small cell.

■■ 3.5GHz With current traffic requirement trend, operators are increasingly looking at solutions from three aspects including band expansion, denser network, airinterface efficiency. Thus, heterogeneous networks where the wide area coverage layers are integrated with additional layers of “small cells” are necessary to provide additional capacity, with wider spectrum bandwidth deployed and enhancing spectrum efficiency. Huawei LTE-Hi (LTE Hotspot & Indoor Enhancement) solution is being developed targeting three aspects: 24

To meet the capacity requirement in hotspot, to seek the wider spectrum for IMT is needed. The 3400-3600 MHz band is ideal for providing such kind of focused coverage with its large amount of contiguous spectrum available. This band also helps in the interference management associated with denser cellular because of its reduced coverage capability which helps. This band has great potential to become a globally harmonized band with at least 50MHz allocated. 3.5GHz is potential to become a global harmonized spectrum band. In the future, if other services such as FSS quit from this band to the other band or can share the frequency bands with IMT, it is potentially 800MHz spectrum band from 3.4 to 4.2GHz, and additionally 600MHz from 4.4 to 5GHz, for IMT. This is very good for the future development of the wireless market and the interest of the global industry chain. 3.5GHz has many band characteristics adapt to the dense ”small cells” for offloading traffic. •• High bandwidth: to fulfill the requirement of increasing capacity •• High propagation loss: more fit for small coverage •• Reduced coverage capability: to help in interference management associated with denser cellular LTE-Hi is the promising “small cell” technology being developed in R12. Its working frequency includes 3.5GHz.

4.2 SDL (SUPPLEMENTAL DOWNLINK) Following is some content discussed in ITU-R WP 5D is excerpted as below16: “Some developments of IMT technologies Among the developments are new technical and operational aspects of IMT systems and arrangements, which may include other characterizations of the use of spectrum, such as: •• Asymmetric FDD uplink (traditionally in lower bands) and downlink blocks (with one or more separate downlinks which could also be in different bands). •• FDD or TDD uplink and downlink for very high peak data rates in confined and densely populated indoor areas as well as in confined areas of moving vehicles. •• FDD and TDD backhauling from, e.g. trains, buses and other vehicles or from body area networks to the host IMT network •• In-band or out-of-band backhauling of small cells.” For the unpaired spectrum used as SDL, it should be noted that the spectrum in some regions can also be used for TDD under demands of regulatory bodies.

16

25

Revision 2 to Document 5D/TEMP/55-E, ITU-R WP5D meeting, 11 October 2012

The 716~728 MHz was initially planned to be used for mobile TV services in the USA, later is proposed to be only used for DL for LTE, and defined as Band 29 with duplex mode with FDD in 3GPP. 700MHz Spectrum in US 698

704

A

710

B

716 722

C

D

728

E

734

A

740

B

746

C

758

C

763

776

D

788

C Public Safety

Digital and analog Broadcasters

Downlink

793

806

D Public Safety

DL only spectrum

Uplink Figure 12 700MHz frequency arrangement of USA

SDL concept was also discussed in CEPT in the context of the L-Band and in ITU.

4.3 LTE carrier aggregation 4.3.1 CA with same mode CA (carrier aggregation) means coordination transmission and coordination reception at two or more carriers in the same band or different bands. Signals at these aggregated carriers are dealt with together at the same baseband unit. CA is classified with intra-band CA and inter-band CA.

Intra-band CA 3GPP RAN4 studies intra-band carrier aggregation for following bands according to operators’ actual requirement, including intra-band continuous CA and noncontinuous CA. Intra-band continuous CA17 •• TDD band: Band 38 (2.6GHz), Band 41; •• FDD band: Band 7 (2.6GHz), Band 1; Intra-band non-continuous CA: •• FDD band: Band 3, Band 4, Band 25. CA impact on BS RF requirement is small, and main impact is on UE requirement. For those continuous scenarios still being studied, the key focus is on UE back-off power. Non-continuous CA may have big impact on UE, so we should keep an eye on it.

17

3GPP Band number see table 4 in section 3.1 of this WhitePaper.

26

Inter-band CA The topic studies RF requirement at scenario of inter-band CA. The requirement comes from operators owning the band. In Rel-11 the scenarios are independently studied in different WI.

Inter-band CA WIs in 3GPP RAN418

Region

CA Class

LTE Advanced Carrier Aggregation of Band 3 and Band 7

EU

Class A3


USA

Class A1


USA

Class A2


USA

Class A1


USA

Class A2


USA

Class A1


USA

Class A3


USA

Class A3


EU

Class A1


China

Class A3


EU

Class A3


EU

Class A1


Korea

Class A1


USA

Class A3


EU

Class A4


Japan

Class A1


Japan

Class A1


Japan

Class A5


Japan

Class A5

LTE Advanced Carrier Aggregation of Band 3 and Band 5, 2UL

Korea

Class A1


Asia, EU

Class A2


USA


USA


Japan


Asia, EU


Japan


Korea

LTE-Advanced Carrier Aggregation of Band 38 and Band 39

China


USA

LTE-Advanced Carrier Aggregation of Band 39 and 41

China


Korea

18

27

3GPP Band number see table 4 in section 3.1 of this WhitePaper.

All inter-band CA combinations only finish the scenario of one-carrier UL in Rel11. The work on two UL carriers simultaneously transmitting is postponed to Rel12. In Rel-12, 5 WIs on CA are created according to the type of CA combination. The main discussion focusing on inter-band CA is filter insertion loss of terminal, because insertion loss will influence power back-off and desensitization, thus coverage about DL and UL will be influenced.

4.3.2 CA with mixed mode Except for CA combination between bands with same mode (e.g. TDD vs. TDD, FDD vs. FDD), hot trend is CA combination based on TDD band + FDD band.

There are two possible scenarios: •• Inter-site FDD + TDD CA, i.e. Macro site with FDD, small cell with TDD •• Co-site FDD + TDD CA It is estimated that FDD+TDD CA is future trend and may be standardized. In different regions, FDD bands and TDD/unpaired spectrum are different, thus the possible combinations are different.

Region 1 Many FDD operators hold TDD spectrum of 1.8/1.9/2.0GHz, In EU countries, 2.6GHz was already auctioned or is on the agenda of auction. FDD bands: DD800, 1.8GHz, 2.6GHz FDD part; TDD bands: 1.9/2.0GHz, 2.6GHz TDD part; Future TDD bands: 3.7GHz, 3.5GHz (if TDD is chosen)

Possible combinations: •• DD800 FDD + 1.9/2.0GHz TDD •• 1.8GHz FDD + 1.9/2.0GHz TDD •• DD800 FDD + 2.6GHz TDD •• 1.8GHz FDD + 2.6GHz TDD •• 2.6GHz FDD + 2.6GHz TDD •• FDD band + 3.7GHz/3.5GHz

28

Region 2 In US, TDD or unpaired spectrum for IMT is mainly located at 2.6GHz, future possible 3.5GHz. 2.6GHz TDD spectrum is held by the TDD only operators who have no FDD spectrum. So it is impossible to have FDD+TDD CA combination. Future possible 3.5GHz band: whether to have FDD+TDD CA combination is dependent on whether FDD operators will own the band.

Possible combination: •• 700MHz FDD + 3.5GHz

Region 3 There are different situations in each country. In China, concept of FDD + TDD CA is difficult to be approved unless TDD operator i.e. CMCC will be permitted to operate FDD LTE network. In Japan, it is very highly possible to deploy FDD+TDD CA network. FDD bands: currently 2.1GHz, 1.5GHz, 1.7GHz and 850MHz; future possible band 900MHz, 800MHz. TDD bands: 2.6GHz and possible band 3.5GHz

Possible combinations: •• FDD: 2.1GHz, 1.5GHz, 1.7GHz, 900MHz, 800MHz + TDD: 3.5GHz •• FDD: 1.5GHz, 900MHz + TDD: 2.6GHz In other countries, possible combination is 1.8GHz FDD + 2.6GHz TDD.

4.3.3 Conclusion for CA There are over 30 work items on intra-band and inter-band CA in 3GPP RAN4 which shows strong interests of operators to better utilize their existing spectrum. CA as a feature introduced in Rel-10 provides one feasible solution to meet this spectrum utilization requirement. It is also expected that mixed TDD + FDD inter-band CA is future trend.

29

4.4 LTE roaming Compared to GSM and UMTS, the main issue for LTE spectrum is the fragmented availability: many bands but none of them suitable for global roaming band. Currently, FDD frequency bands for commercial or trial LTE networks include: •• Europe: 800M (Band 20), 1800M (Band 3 GSM refarming), 2600M (Band7), •• US & Canada: 700M (Band 13, Band 17), AWS (Band 4, Band10) •• Japan: 850M (Band 18), 1500M (Band 21), 2100M (Band 1), •• Korea: 850M (Band 5) •• Latin America: 700M, AWS (Band 4, Band10), 1800M (Band 3 GSM refarming), 2100M (Band 1), 2600M (Band 7)

TDD frequency bands for commercial or trial LTE networks include: •• US: 2600M (Band 41) •• China: 2300M (Band 40 Trial network for indoor application), 2600M (Band 38 Trial network), 1900M (Band 39 Trial network) From the bands to be available for LTE application recently, we can group the bands with the consideration on covered ITU regions.

The bands which can cover 3 ITU regions include: FDD: •• APT 700M (Asia, Europe (if compatibility with APT band plan is adopted), Latin America), 3500MHz TDD: •• 2300MHz, 2600MHz, 3500MHz The bands which can cover 2 ITU regions include: •• 850MHz, 1800MHz Note: The 850MHz spectrum here is a set of frequency bands rather than a single band.

Regarding the complicated bands situation for LTE, it is not possible to find a single global roaming band. More reasonable way is to use several frequency bands which can cover at least two ITU regions to comprise the roaming spectrum.

For FDD application, candidate bands for roaming band combination include: •• 1800MHz, E850MHz, APT 700MHz, US 700MHz

For TDD application, candidate bands for roaming band combination include: •• 2.3GHz, 2.6GHz, 3.5GHz Note that except for the candidate bands, roaming via FDD is also a possible 30

700MHz Bands: B12 716

698

B17 Region 2

704

728

716

746 734

746

B13 746

756

777

787

B14 758

Band 44 Region 3

Band 28

Region 1

CEPT

768

788

798

703

803

703

748

758

803

791

698

850MHz Bands:

Region 2

Lower E850 806

824

851

869

Upper E850 814

Band 5

849

894

859

Band 18

Region 3

815

Band 19

830

875

860 845

890

Source: 3GPP TR 37.806

2600MHz Bands: 2500 MHz

Region 1

Europe

2570

FDD Uplink Blocks

2495 MHz

Region 2

2690

2572

FDD Downlink Blocks

2614

2690

B B R A A A B B B C C C D D D J A B C D G F E K R E E E F F F H H H G G G 4 4 4 4 4 4 4 S 1 2 3 1 2 3 1 2 3 1 2 3 S 1 2 3 1 2 3 1 2 3 1 2 3 1 2

The US

16

Region 3

2620

TDD or FDD Downlink(External)

Some AsiaPacific countries

5.5*12

4

6*7

2500 MHz

4 6

5.5*12

2635

Mobile Communication Service

2660

BSS

2500 MHz

CHINA

Mobile Comm. Service 2690 MHz

TDD

Figure 13 Global frequency arrangements of 700MHz, 850MHz and 2600MHz 31

2690

5 TDD spectrum application 5.1 TDD spectrum Spectrum is the king for operator’s competency. Many mobile carriers put increasing emphasis on TDD spectrum and its usage. Currently core bands for TDD are 1.9GHz, 2.0GHz, 2.3GHz and 2.6GHz. There is totally about 440MHz bandwidth spectrum. In future, new candidate bands e.g. 3.5GHz and 3.7GHz may bring additional 400MHz bandwidth spectrum for TDD.

Analysis Different TDD band has different band characteristics adapted to the different application and scenario. •• Band 1.9GHz/2.0GHz: region 1 and region 3; small bandwidth (15MHz~20MHz), low propagation loss and penetration loss •• Band 2.3GHz: ongoing discussion in region 1, WCS (FDD application) in region 2, IMT in region 3; large bandwidth (100MHz), relatively low propagation loss and penetration loss •• Band 2.6GHz: small bandwidth(50MHz) in EU large bandwidth (190MHz) in US and China, relatively high propagation loss and penetration loss •• Band 3.5GHz/3.7GHz: ongoing in different regions; very large bandwidth (200MHz), high propagation loss and penetration loss Thus, band 2.3GHz/2.6GHz can be used to increase capacity and 3.5GHz/3.7GHz is more adaptable for small cell application to offload traffic. These spectrum distribution among different regions are briefly summarized as below: From the technology point, in band 1.9GHz/2.0GHz 3G TDD (TD-SCDMA) was deployed only in China. In other bands LTE TDD is the only choice. If there are several operators in same band, need a guard band (around 10MHz) between each adjacent operator or to synchronize the TDD networks.

Dedicated band 1.9GHz/2.0GHz In region 1, 1900-1920MHz (Band 33) and 2010-2025MHz (Band 34) are currently allocated to UMTS networks but remain unused throughout the EU. The 32

European Commission has already issued a Mandate to CEPT to study suitable alternative applications and develop appropriate technical conditions and sharing arrangements. Spectrum of 1880-1920MHz is allocated as Band 39 for LTE TDD in China. However, 1900-1920MHz within this band is currently occupied by PHS in China. Up to Oct. 2012, there are still over 13 million subscribers in the PHS network. Ministry of Industry and Information Technology of China (MIIT) has confirmed that the spectrum shall be cleaned up for deployment of LTE TDD and announced in Sep. 2012 that the LTE TDD license will be issued in about one year. This band will play an important role for LTE TDD development in China. In the first half year of 2012, CMCC has finished network test of LTE TDD trial. 11 cities have set up the trial network until the end of 2012 and a LTE FDD/TDD mixed commercial network has been launched in Hongkong by CMCC.

2.3GHz For 2.3GHz, non-mobile service is operated at the band in most countries and only in small number of countries, mobile service is operated. In EU, current usage is complex. LSA (licensed shared access) is hot issue in the discussion in possible usage ways, but and maybe, could be static (without consequence on the 3GPP standard). According to ECC WG FM questionnaire, there are 12 countries which have no plan in addition to current non MBB use and 5 countries that might support an EC/ECC harmonization. In US, the band was assigned to WCS service in 1997. Now part of the band is planned to be used as FDD systems. In China, because of earlier military application, the band is only used in indoor scenario before. MIIT in China formally announced that 2.3GHz can be used for outdoor scenario after permission in Sep. 2012.

2.6GHz Earlier allocation for this band is WiMAX. Many operators hold the spectrum more than 20MHz. In recent years, the band already is allocated to LTE application in Europe, US, China, etc. Although the band is intended for global harmonization, actually there are two streams for allocation. •• Option1: sandwich allocation, mainly in EU (Region1) 2500 MHz

2570 FDD UE Tx

2620 TDD

2690 FDD BS Tx

Figure 14 Sandwich frequency arrangement of 2600MHz 33

In case of coexistence between TDD BS and FDD BS with the same class, guard band is necessary to avoid interference. Guard band is from 5MHz to 10MHz depending on the scenarios. •• Option2: all band for TDD, or there is no FDD allocation in the band, mainly in US, China. Currently, CMCC holds the band 2570-2520MHz for LTE-TDD trial network. It can be estimated that existing status will be maintain in future and another operator may also come in and hold some of the band. At least two operators may share this band including CMCC and China telecommunications with high possibility.

Summary With more and more spectrum available for TDD and the development of Hetnet, complicated network with multiple operators and multiple layers becomes a trend. It will bring co-existence problem especially for TDD because of the challenge for synchronization between BSs. Synchronization becomes an imperative issue to be solved for TDD.

5.2 TDD synchronization When multiple operators deploy TDD system in the same band and in the same geographic areas, severe interferences may happen if the networks are uncoordinated. For example, if some base stations (BSs) are transmitting while others are receiving, the transmitter may desensitize or block the neighbor receiver due to imperfect emission on the transmitter side and adjacent channel selectivity on the receiver side.

Operator B uplink → Operator A downlink (UE to UE interference)

Operator A downlink → Operator B uplink (BS to BS interference)

Un-synchronization between operator A and B Operator A Operator B

D S U U D D S U U D D S U U D D S U U D

Figure 15 Interferences between uncoordinated TDD systems in the same band and areas 34

There are several possible techniques for improving coexistence between TDD networks like: •• Synchronization •• Sub-band filtering •• Site coordination •• Restricted blocks The use of sub-band filtering and restricted blocks methods are obviously methods which lead to spectrum wastage. Sub-band filtering method also increases the number of base station types even within the same band and destroy the economies of scale. Site coordination method will bring very complicate site plan and site construction. Therefore, a better way to avoid interferences is to synchronize neighbor BSs in order to make them transmit and receive at the same time. Some supervisors also make the synchronization between operators as mandatory rules to guarantee the co-existence. It can be explained to two points as below: •• Synchronizing the beginning of the frame •• Configuring compatible frame structures There are several methods for synchronization of the start of frame: GNSS (like GPS), synchronization over backhaul network (like IEEE 1588 v2), and synchronization through the radio-interface (like network listening). For outdoor base stations like macro/micro cells, it is easy to get synchronization by GPS. But with the development of heterogeneous network, more and more base stations are planning to deployed indoor to improved the hotspot throughput. GPS and IEEE 1588 are not always available or suitable for small cells. In this case, overthe-air synchronization approach can be used. This approach can be used for the BSs not only within a single operator but also between different operators with multiple layers sharing the same band. The following figure shows a feasible way to implement synchronization across different operators.

Declaring Channel

Introduce "Declaring Channel" to make it possible to save GB

BS A

BS B

N

Synchronization Recalibration

Initial Synchronization

Synchronization Tracking

BS C

N Common Notification Channel

Figure 16 A feasible way to implement synchronization across different operators 35

The procedure includes: •• Declaring Channel: Each operator broadcasts/monitor the spectrum usage information. •• Initial Synchronization: keep synchronization with the deployed BS (target BS) •• Synchronization Tracking: keep synchronization periodically. •• Synchronization recalibration. 3GPP will still further enhance the current synchronization mechanisms for the scenario of multi-carriers and multi-layers in the later releases.

6 Annex 6.1 Coordinating framework There are 3 levels for the coordinating framework of the international use of the radio spectrum. •• The first level: ITU-R for Global regulations (Coordinating the international use of the radio spectrum in the world) •• The second level: Regional Organizations for Regional regulations (Preparation of common coordinated proposals in the region) •• The third level: Administrations for national regulations (Governmental department for the national frequency arrangement and management)

Administrations

ITU

Regional Org.

External Org.

Figure 17 Coordinating framework of the international use of the radio spectrum 36

111 ITU-R The ITU Radiocommunication Sector (ITU-R) specializes in facilitating international collaboration to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum and satellite orbits, by: •• Holding World and Regional Radiocommunication Conferences (WRC and RRC) 1 to expand and adopt Radio Regulations (RR) and Regional Agreements covering the use of the radio-frequency spectrum; •• Establishing ITU-R Recommendations, developed by ITU-R Study Groups (SG) in the framework set by Radiocommunication Assemblies (RA), on the technical characteristics and operational procedures for radiocommunication services and systems; •• Coordinating endeavors to eliminate harmful interference between radio stations of different countries; •• Maintaining the Master International Frequency Register (MIFR), Based on inputs from administrations; •• Offering tools, information and seminars to assist national radio-frequency spectrum management. ITU-R is responsible for coordinating the international use of the radio spectrum. The conferences and important outcome of ITU-R are as follows19.

Revisions to RR, Resolutions & Recommendations

ITU Member States (193) Technical bases Rec

CPM

RA

SGs & SC

Final Acts

WRC

RR

Director

RRB

Radiocommunication Bureau RofP

RAG CPM: Conference Preparatory Meeting Rec: ITU-R Recommendation RofP: Rules of Procedure RR: Radio Regulations (treaty status)

RAG: Radiocommunication Advisory Group RRB: Radio Regulations Board SGs & SC: Radiocommunication Study Groups and Special Committee WRC: World Radiocommunication Conference

Figure 18 Importance conferences and outputs of ITU-R

19

37

From ITU-R website

The World Radiocommunication Conference (WRC) is the most important conference in ITU-R, normally held one month long every four to five years. •• The WRC is the forum where countries decide on the shared use of the frequency spectrum to allow the deployment or growth of all types of radiocommunication services that have global implications •• WRC decisions are contained in Final Acts which include amendments to the Radio Regulations (RR, treaty status) •• The Radio Regulations provide for the allocation of radio frequency spectrum to various radio services (e.g. broadcasting, satellite communications, radiolocation and mobile). •• The Radio Regulations also provide the technical provisions for sharing radio frequency spectrum among radio services and the regulatory provisions for bringing into use new radio based systems. •• Adopts Resolutions covering technologies and future work of the ITU-R.

222 Regional Organizations and Administrations For the allocation of frequencies the world has been divided into three Regions as shown on the following map20. The detail information about the area which is included in each Region can be found in Radio Regulations.

Figure 19 Three Regions in the world

20

From Radio Regulations published by ITU-R

38

There are six main regional organizations in the world. •• Inter-American Telecommunications Commission (CITEL) •• European Conference of Postal and Telecommunications Administrations (CEPT) •• Asia Pacific Telecommunity (APT) •• African Telecommunications Union (ATU) •• Arab Spectrum Management Group (ASMG) •• Regional Commonwealth in the field of Communications (RCC)

Each of the Regional Spectrum organizations has a WRC preparatory function. •• Administrations in each Region will submit draft proposals to the Regional Spectrum organizations. •• The regional organization will adopt common proposals before the WRC in accordance with their own procedures. •• The regional proposals are submitted to the WRC on behalf of all of their Members.

Figure 20 Six main regional organizations in the world

39

7 References 111 3GPP 37.104 v11.2.1 222 Report ITU-R M.2024(2000), “Summary of spectrum usage survey results” 333 Report ITU-R M.2072(2006), “World mobile telecommunication market forecast” 444 Report ITU R M.2074(2006), “Radio aspects for the terrestrial component of IMT-2000 and systems beyond IMT-2000” 555 Report ITU-R M.2078(2006), “Estimated spectrum bandwidth requirements for the future development of IMT-2000 and IMT-Advanced” 666 Report ITU-R M.2079(2006), “Technical and operational information for identifying Spectrum for the terrestrial component of future development of IMT-2000 and IMT-Advanced” 777 Recommendation ITU-R M.1036-4(03.12), “Frequency arrangements for implementation of the terrestrial component of International Mobile Telecommunications (IMT) in the bands identified for IMT in the Radio Regulations (RR)” 888 Radio Regulations (Edition of 2008) 999 Provisional final acts (WRC-12)

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