Prepared byBerge Ayvazian Senior Consultant, Heavy Reading www.heavyreading.com November 2013 Special Research Report LTE TDD Services in the 3.5GHz Bands Opportunities & Challenges for LTE-Hi HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 2 Executive Summary Mobile broadband demand is at an all-time high, with some operators reporting a doubling of data traffic during each of the last five years. With increasing adop- tion of sophisticated smartphones and tablet devices, more and more users are turning to mobile broadband (MBB) as their primary means for Internet access, content, applications, communications and messaging. In particular, video streaming, content downloading, gaming and other high- bandwidth, data-intensive multimedia applications are accelerating mobile data traffic growth. We are reaching a point of network saturation as more smart devices are penetrating the market, enabling users to satiate their hunger for advanced services and applications. As such, mobile data traffic is expected to grow 30-fold over the next few years and 1,000-fold over the next 10 years. Mobile operators are just beginning to consider steps to handle this scale of mobile data traffic growth, especially in urban centers where traffic can spike to 10 times average levels in the busiest hours. The UMTS Forum now estimates that over 880 MHz of new spectrum will be needed to address this growth for the next 10 years. There is a growing recognition that only the combination of small cells, cloud radio access network (RAN) and large blocks of new Long Term Evolution (LTE) spectrum will allow operators to address this 1,000-fold challenge. Mobile technologies have evolved from 3G to 4G HSPA+ and LTE in order to provide increased mobile broadband data capacity at a lower cost per bit, while reducing latency and improving the customer experience. In many countries, competitive and market forces have combined to accelerate deployment, aggressive marketing and rapid adoption of 4G LTE. The most recent GSA report indicates that 213 LTE networks have been commer- cially launched in 81 countries, reaching 126 million subscribers by October 2013, concentrated in North America and the Asia/Pacific region. Most of these initial LTE deployments have used paired frequency-division duplex (FDD) spectrum in the 1800-, 2600- and 700MHz bands. The GSA has also identified 23 LTE time-division duplex (TDD) commercial networks in 18 countries, with nearly all using Band 40 2.3GHz or Band 41 2.6GHz spectrum. Figure 1 indicates that the 11 LTE TDD spectrum bands specified by 3GPP tend to use higher frequencies and offer large spectral capacity, some with 100MHz contiguous spectrum blocks. Test-Driving TD-LTE Advanced The most recent meeting of the 3.5GHz Interest Group of the Global TD-LTE Initiative (GTI) attracted more than 120 participants from 17 countries, and it was held in Tokyo to allow attendees to experience the Softbank field test demo of TD- LTE Advanced technology in the 3.5GHz spectrum Band 42. This Heavy Reading Special Research Report showcases the results of the Softbank TD-LTE trial and discusses how operators can use 3.5GHz TDD spectrum to improve network performance leveraging new technologies like LTE Hotspot Improvements (LTE-Hi) and carrier aggregation for LTE Advanced. The Softbank field test-drive demo of the world's first trial network supporting TD-LTE Advanced technology in the 3.4-3.6GHz band was quite impressive. Driving HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 3 through the crowded streets in Tokyo's densely-populated Ginza district, partici- pants saw the density of SoftBank's network of rooftop LTE antennas, with a live measurement of average download speeds of 500 Mbit/s and peak download speed reaching 770 Mbit/s. Huawei helped build this SoftBank pre-commercial trial TD-LTE network using cutting-edge LTE Advanced technologies to achieve those download speeds with 100 MHz of 3.5GHz spectrum, including beam-forming antennas, carrier aggregation, 4x4 MIMO, interference cancellation, coordinated multi-point (CoMP), ultra-wideband remote radio units (RRUs) and cloud RAN, in which baseband units are pooled in telco central offices. Figure 1: Total Available Spectrum in LTE TDD Spectrum Bands Specified by 3GPP BAND BAND “IDENTIFIER” FREQUENCIES (MHZ) TOTAL AVAILABLE SPECTRUM 33 34 TDD 2000 Europe 1900-1920 2010-2025 20 MHz 15 MHz 35 36 TDD 1900 1850-1910 1930-1990 60 MHz 60 MHz 37 PCS Center Gap 1910-1930 20 MHz 38 IMT Extension Center Gap 2570-2620 50 MHz 39 China TDD (current TD-SCDMA band) 1880-1920 40 MHz 40 2.3 TDD (Malaysia, China & India) 2300-2400 100 MHz 41 U.S. TD-LTE 2496-2690 194 MHz 42 3.5/3.6 GHz 3400-3600 200 MHz 43 3.7 GHz 3600-3800 200 MHz 44 ATP 700 703-803 100 MHz Source: Heavy Reading and 3GPP HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 4 3.5/3.6GHz Spectrum for Small-Cell Capacity The highest concentration of mobile data traffic growth is in urban hot zones and indoor hot spots, where operators are planning to deploy small cells on top of the macro cell layer in a heterogeneous mobile broadband network. Taking this small- cell deployment scenario into account, LTE-Hi has been proposed to optimize small-cell spectral efficiency enhancements, efficient operation with traffic adaptation and interference coordination, heterogeneous network (HetNet) mobility enhancement and multi-stream aggregation, as well as the potential for HetNet FDD and TDD joint operation. Softbank believes the release of 3.5/3.6GHz spectrum for mobile operators is critical for unleashing the power of LTE-Hi and TD-LTE Advanced technologies. Figure 2 demonstrates that the lower 700-900MHz FDD frequency bands with 3+ kilometer coverage range are best suited to deploying LTE macrocell networks for broad nationwide and rural coverage. The most widely used Advanced Wireless Services (AWS) spectrum band with 1.5 kilometer coverage range is well suited for LTE coverage in regional metropolitan areas. Although the 0.3 kilometer coverage range in the 3.5/3.6GHz spectrum band is challenging for achieving broad nationwide coverage, these propagation-loss characteristics make Band 42 ideal for high-frequency reuse to enable dense small-cell deployments, and the large blocks of spectrum available in this band fare well for dramatically expanding broadband capacity in urban areas. The challenges posed by small-cell deploy- ments with limited coverage areas can be addressed by the coordination of radio resource utilizations and mobility management across multiple cells, especially when using baseband pooling. Figure 2: Coverage & Capacity for Key LTE Spectrum Bands Source: Heavy Reading and 3GPP HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 5 The most important drivers for TD-LTE deployments using spectrum in the 3.5/3.6GHz bands, highlighted by China Mobile and SoftBank, are: Limited coverage, low mobility and isolation makes higher frequency Band 42 attractive for outdoor rooftop and street level small cells in urban hot zones. 3.5/3.6GHz spectrum offers high throughput for both outdoor and indoor hot zones. 200 MHz of available spectrum is ideal as a dedicated large-bandwidth small-cell band to boost hot zone capacity on top of the macro cell cov- erage layer. 3.5/3.6GHz spectrum using TD-LTE solutions is well suited for handling the severe unbalance and fluctuation of downlink/uplink traffic in each hot zone area. 3.5/3.6GHz spectrum offers greater isolation to avoid interference, ensure quality of service (QoS) and enable frequency reuse in the high frequency band. HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 6 Operator Strategies for TD-LTE 3.5GHz Networks This SoftBank TD-LTE Advanced technology demo in Tokyo was conducted during the 3.5GHz Interest Group Workshop and Ad Hoc Seminar hosted by the GTI that attracted the participation of 120 participants more than 17 countries. In addition to SoftBank Mobile, operator participants representing China Mobile, UK Broad- band, Bolloré Telecom and Wateen Telecom offered their insight on the best use of 3.5GHz spectrum to enhance mobile broadband deployment and increase capacity for TD-LTE small cells both outdoors and inside buildings. The WiMAX Forum estimates that more than 300 operators own 3.5/3.6GHz spectrum and that many provide fixed/nomadic broadband wireless access (BWA) services using WiMax technology. Figure 3 provides a representative list of these operators' current services using 3.5/3.6GHz spectrum to provide BWA in more than 20 countries by region. Figure 3: Operators Licensed to Use 3.5/3.6GHz Spectrum by Region REGION COUNTRY OPERATOR TECHNOLOGY Europe U.K. Ireland France Belgium Italy Germany Spain Spain UK Broadband Imagine Communications Bolloré Telecom b.lite Telecom BVBA AFT-Linkem Deutsche Breitband Dienste Neo-Sky Iberbanda/Telefónica TD-LTE WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE Eastern Europe Russia/CIS Poland Russia Azerbaijan Netia, Milmex TransTeleCom, Enforta Azqtel (Sazz) WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE Middle East/ Africa Saudi Arabia Bahrain Jordan Iran Pakistan South Africa Kenya Nigeria Mobily Mena Telecom Umniah MobinNet Wateen, Augere, Wi-Tribe Neotel, Easttel Safaricom, AccessKenya Swift, ADIV WiMax to TD-LTE WiMax to TD-LTE WiMax to TD-LTE WiMax WiMax WiMax/TD-LTE dual-mode WiMax WiMax/TD-LTE dual-mode Asia/Pacific Australia Vivid Wireless/Optus WiMax/TD-LTE North America Canada Mexico Bahamas Jamaica Xplorenet, Bell Canada Axtel, Telmex BTC Digicel WiMax to TD-LTE WiMax to TD-LTE TD-LTE WiMax Latin America Argentina Chile DirecTV Entel WiMax to TD-LTE TD-LTE Source: Heavy Reading HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 7 Many of these operators initiated BWA service using WiMax technologies and some are now seeking to leverage their vast spectrum positions and transition to TD-LTE. The 3.5GHz Interest Group has reached a consensus that LTE TDD should be the main evolution choice for WiMax operators. However, the BWA business model still has traction where 3.5GHz band is being used to provide essential fixed and nomadic wireless broadband services. In Pakistan, Wateen, WiTribe and Mobilink now serve 460,000 broadband wireless subscribers using WiMax in the 3.5GHz band; MobinNet is another 3.5GHz WiMax operator that provides wireless broadband service nationwide and serves more than 500,000 subscribers in Iran. But many existing 3.5GHz WiMax operators are not financially viable and need a near-term plan to access a broader ecosystem of devices and operate more easily within the new LTE HetNet environment. Some of these operators are hoping to enhance their operations by leveraging WiMax Advanced Release 2.2 technology to support the convergence of WiMax and TD- LTE services. The following are among the 3.5GHz operators seeking to evolve their existing WiMax networks to LTE TDD for a better user experience beginning in 2013: UK Broadband conducted a TD-LTE pilot in 2012 and launched commer- cial service using 3.5/3.6 GHz spectrum in June 2012. Bolloré Telecom from France plans to launch TD-LTE services in Band 42. Ireland's Imagine Group has 220 MHz in Band 42/43. Originally offered Wi- Max in all strategic parts of Ireland; now plans to launch TD-LTE in 2013. Xplornet Communications of Canada is testing the migration from WiMax to TD-LTE network with 25 MHz in the 3.5GHz band. AFT-Linkem, a WiMax operator with 130,000 subscribers in 13 regions of Italy, is conducting a trial of TD-LTE in the 3.5GHz band. Neo Sky in Spain is studying the introduction of a 3.5GHz TD-LTE system. Enforta, a Russian WiMax operator, plans to test TD-LTE in the 3.5GHz band. Mobily in Saudi Arabia is working with Huawei and Samsung to migrate its existing WiMax network to be the first WiMax/TD-LTE multimode in the 2.5GHz Band 41. Mobily will use some 2,400 LTE towers in more than 30 cit- ies to support 2 million mobile broadband subscribers and also plans to deploy TD-LTE with 3.5GHz spectrum in the future. WiMax network into the first WiMax/TD-LTE multimode network in Band 41, with 2 million subscribers. Mobily also plans to deploy TD-LTE with 3.5GHz spectrum in the future. Menatelecom, a WiMax operator in Bahrain, is currently working with Huawei to deploy a nationwide TD-LTE network at 3.5GHz, planning to launch commercial service in 2013. Swift in Nigeria is deploying West Africa's first WiMax/TD-LTE dual-mode network using 3.5GHz spectrum. The following profiles provide more details on operators with using 3.5/3.6GHz spectrum that are considering the transition from WiMax to TD-LTE. UK Broadband – First to Deploy TD-LTE in 3.5GHz Band UK Broadband (UKB) has been leading the 3.5GHz TD-LTE movement, and was world first operator to deploy a TD-LTE network in the 3.5/3.6GHz LTE Bands 42 and 43 beginning in 2012. UKB was also the first commercial 4G deployment in the U.K. HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 8 Using Huawei's TD-LTE base station solution, the UKB network initially covers the South Bank and Borough areas of Southwark in the south of London. A subsidiary of Hong Kong-based PCCW, UKB has adopted a wholesale business model to deploy bespoke LTE coverage that delivers solutions to where there is demand for high-speed wireless/mobile data capacity. The UKB TD-LTE network uses 124 MHz of 3.5/3.6 GHz of unpaired spectrum, which allows the deployment of 6 x 20MHz wide channels for access and 2 GHz of spectrum for backhaul. This enables UKB to deliver LTE Advanced speeds and enough capacity across the network to deliver next-generation access superfast broadband speeds to a large number of users simultaneously. UKB has one of the largest 4G spectrum holdings in the U.K., even after the recent auction releasing 250 MHz of 4G spectrum in the 800MHz and 2.6GHz bands. The U.K.'s mobile operators are now deploying their initial LTE coverage networks and UKB is prepared to offer additional LTE capacity using its 3.5GHz spectrum as the need unfolds. UKB is currently working with anchor or core customer partners to offer superfast mobile broadband services to consumers and commercial businesses, as well as public sector "wireless city deployments" across the U.K. Although its 3.5/3.6GHz spectrum license allows the carrier to deploy either FDD or TDD technology, UKB has chosen to deploy TD-LTE because it is specifically designed to meet the rapidly growing demand for download data capacity. TD LTE allows UKB to dynamically manage the network to maximize the download capacity at all times, optimizing both the technology and the wide spectrum bands it has available to deliver a very high download capacity. As mobile data becomes increasingly asynchronous, TDD technology enables network resources to be fully optimized, whereas FDD would be underutilized in these situations. As data demand on the move increases, TDD will start to be more widely used to meet customer demands and drive an optimum return for the operator. UKB believes TD-LTE technology is rapidly maturing and the ecosystem is develop- ing, although there are still several practical device challenges to be resolved before operators can fully leverage the new capabilities being developed by standards organizations. Huawei supplied the first multiband and multimode TD-LTE devices used by UKB, including indoor and outdoor units for high-speed wireless broadband to homes and businesses in the coverage area. Multimode mobile smartphone devices supporting TD-LTE, FD-LTE and 3G are in development. Bolloré Telecom – Plans to Deploy TD-LTE in 3.5GHz Band Bolloré Telecom is a subsidiary of the Bolloré Group, one of the 500 leading interna- tional diversified groups, founded in 1822. For several years, Bolloré Group has been investing in the communication and media sectors, and it is now developing its wireless business. Bolloré Telecom is the leading 3.5GHz wireless network operator in France, and Wifirst is the leading French wireless Internet service provider (ISP) and Wi-Fi operator in terms of traffic. Bolloré also owned Autolib, a smart city solutions provider and is a key stakeholder in SFR, the second largest French mobile operator. Bolloré Telecom is one of the original WiMax license holders in France selected in 2006 to use the 3.5GHz band to offer fixed wireless Internet services, especially in areas not reached by ADSL. In 2008, Bolloré Telecom acquired of eight of the 11 regional WiMax licenses held by TDF WiMax subsidiary HDRR and two regional licenses from Altitude Telecom. These were combined with its existing 12 licenses to launch a high-speed Internet service nationally. Its national license for 30 MHz of 3.5GHz spectrum now covers 65 million people. HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 9 The Bolloré Telecom network deployment took longer than expected, and the WiMax technology was initially used in rural areas to cover zones beyond the reach of landline DSL networks. Bolloré learned many lessons from its effort to build a viable network and business using WiMax in the 3.5GHz band. The WiMax vendor ecosystem was not reliable, and the company claimed it was unable to deploy a fully-functioning WiMax network due to equipment vendors abandoning the technology. For several years the company was threatened to lose its 3.5GHz licenses, since only 200 of the several thousand WiMax base stations the ISP was obliged to deploy were ultimately installed given their limited coverage. In return for retaining its licenses, Bolloré has committed to keep control of Bolloré Telecom and to meet all of its deployment obligations by 2017, while continuing to making its spectrum available to local governments. It has agreed to return this spectrum if it does not meet its obligations. Bolloré Telecom is now seeking to convert to LTE its 3.5GHz spectrum operator license national WiMax network to TD- LTE. It plans to refocus on the top 15 urban areas, reaching 24 million people and most of the smartphones in France. Phase 1 of this plan is to be completed within 18-24 months, delivering capacity where it is really needed and ensuring the service is transparent across multiple networks. The company is also seeking regulatory reforms that would remove technology restrictions on its 3.5GHz spectrum license that prevent mobility and backhauling. Ultimately, Bolloré would like French regulators to adopt the CEPT/ECC PT-1 band plan to release more TDD spectrum in the 3.5/3.6GHz bands. Bolloré sees great potential for 3.5GHz spectrum to add capacity to SFR's existing LTE FDD network and to offer high-speed broadband in urban areas. But this depends on the growth of the vendor ecosystem, new chipsets and low-cost terminal devices. Wateen Telecom – 3.5GHz WiMax Operator in Pakistan Wateen Telecom is the Abu Dhabi Group's latest communication investment in Pakistan after the successful launch of Warid Telecom post-paid GSM network. Headquartered in Lahore, Wateen's nationwide spectrum holdings in the 3.5- 3.6GHz band include five geographic regions with 42 MHz of spectrum and nine geographic regions with 21 MHz of spectrum. Wateen has successfully deployed a nationwide WiMax network with coverage in 19 cities, covering more than 20 percent of Pakistan's 164 million inhabitants. Since the network's commercial launch in December of 2007, Wateen Telecom currently serves 185,000 subscribers. Wateen is close to achieving EBITDA break-even on existing operations, while addressing the challenge of subsidizing expensive 3.5GHz WiMax devices and poor performance of WiMax USB modems in indoor environments. Wateen is working to consolidate its assets with another 3.5GHz WiMax operator in Pakistan to aggregate spectrum and drive economies of scale. Wateen is also contemplating the transition from its existing WiMax network, and the introduction of TD-LTE into its current 3.5GHz infrastructure and device portfolio. This transition is being planned as a layer of TD-LTE on top of its existing WiMax network in high data demand urban areas, driving the following requirements: Preserving interoperability with its existing WiMax network and subscribers Stable, certified, standardized TD-LTE infrastructure equipment in 3.5 GHz A single cabinet to host both WiMax and TD-LTE radio transceiver units would be a desirable feature to save operation and maintenance cost HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 10 A converged backhaul and core should be feasible to manage opera- tional cost and network complexity The ecosystem should evolve such that customers bring their own devices with built-in LTE capabilities in portable devices (mobile/tablets/laptops) The ecosystem should allow customers to buy attractively priced "off-the- shelf" customer premises equipment (CPE) not subsidized by the operator Suitable TD-LTE indoor desktop CPE pricing for the Pakistan broadband market would be below $45 by 2016 Softbank WCP – First to Demo TD-LTE Advanced in 3.5GHz Band SoftBank Mobile is the third largest mobile operator in Japan, operating HSPA+ services using 90 MHz of spectrum in the 900MHz band. Softbank also operates DC- HSDPA at 1500 MHz and HSDPA at 2100 MHz. The company recently launched LTE FDD service nationwide in the 2100MHz band. The spectrum holdings and mobile networks controlled by SoftBank in Japan are summarized in Figure 4. In December 2010, Softbank acquired bankrupt Willcom, which operated a Personal Handy-phone Service using 2.5GHz spectrum. Willcom was renamed Wireless City Planning (WCP) and, with SoftBank as the lead investor, has used its 2.5GHz spectrum to deploy a nationwide TD-LTE compatible, Ad- vanced eXtended Global Platform (AXGP) mobile broadband network through- out Japan. SoftBank Mobile now operates as an MVNO of WCP, offering Softbank 4G-branded AXGP service on that 2.5GHz spectrum. This spectrum in Band 41 is the same spectrum used by Sprint partner Clearwire for WiMax and, starting next year, TD-LTE. Figure 4: SoftBank Spectrum Holdings & Mobile Networks in Japan Source: SoftBank and Wireless City Planning HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 11 SoftBank recently demonstrated the world's first trial network supporting TD-LTE- Advanced technology in the 3.4-3.6GHz band. Its WCP TD-LTE deployment and the field test demo used 3.5/3.6GHz spectrum, supporting small-cell base stations with interference cancellation, MIMO and beam-forming antenna technologies. SoftBank also demonstrated a prototype five-carrier aggregation technology for TD-LTE that can provide a maximum download speed of 1.2 Gbit/s. When de- ployed in combination with ultra-wideband RRUs, this network can support instantaneous bandwidth of more than 100 MHz and can be customized on demand to accommodate new spectrum as it becomes available. But the real key to the trial demo was the use of small cells and more than 100 MHz of spec- trum in the 3.5GHz band, with advanced interference-cancellation technologies that improve quality and performance even at the cell edge. SoftBank believes that paired LTE FDD spectrum ensures symmetrical allocations between uplink and downlink, while LTE TDD allows for more downlink capacity to support video streaming and downloading without the need for guard bands. This trial clearly demonstrated the performance, reliability and stability of LTE TDD technologies in the 3.5GHz band and their effectiveness in solving coverage issues and addressing co-frequency band interference. WCP detailed its deployment of 3.5GHz LTE-TDD small cells at 37,000 sites, offering the capacity needed to handle traffic growth in the major urban areas of Japan and complementing SoftBank's LTE FDD coverage network. All this was designed to show how mobile operators can use TD-LTE Advanced technology, small cells, smart antenna and the 200 MHz of spectrum in the 3.4- 3.6GHz band to achieve peak data rates of 1 Gbit/s to meet the requirements for true 4G IMT Advanced, as defined by the International Telecommunication Union. However, this demo lacked a practical demonstration of the new applications that would be enabled by these blazing-fast download speeds, such as mobile 3D HDTV, virtual reality gaming and mobile telepresence. SoftBank clearly demon- strated that all these resources will be required to achieve the 1,000-fold growth in mobile broadband data traffic expected over the next 10 years. SoftBank WCP also advised existing 3.5GHz WiMax operators to leverage the growing ecosystem of Dual SIM Dual Radio (DSDR) smartphones to offer subscribers a unique combination of nationwide LTE coverage and high capacity in urban hot zones. Rather than selling their spectrum or facing financial collapse, WCP believes that DSDR should be a primary strategy for WiMax operators in the 3.5GHz band. HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 12 Vendor Ecosystem for 3.5/3.6GHz Band 43 Meeting participants attended the GTI 3.5GHz Interest Group Workshop to discuss performance by leveraging 3.5GHz spectrum new TD-LTE technologies. In support of the operator initiatives, the 3.5GHz LTE TDD ecosystem is becoming commercial- ly mature across both the infrastructure chipset and device domains. A large ecosystem of vendors also supported this 3.5 TD-LTE Advanced workshop, includ- ing Airspan, Alcatel-Lucent, Ericsson, Hitachi, Huawei, NSN, Qualcomm, Telrad and ZTE. Each of these vendors is prepared to play a prominent role in the deployment of small cells and TD-LTE Advanced networks using 3.5GHz spectrum. The following summarizes the vendor presentations made available after the workshop: Huawei has extensive experience deploying TD-LTE networks with 3.5GHz spectrum and has emphasized the smooth evolution from WiMax to TD-LTE networks to protect the operator's investment and existing subscriber base. With its large base of WiMax operator customers, Huawei is working with Mobily to deploy the first dual-mode network to rapidly migrate users from WiMax to TD-LTE in Saudi Arabia. Huawei is also working with UKB on the world's first 3.5GHz LTE TDD commercial network and has already demonstrated the world's first 3.5GHz TD-LTE TDD nation- wide network in Bahrain with Menatelecom. Huawei helped build this SoftBank pre-commercial trial TD-LTE network using cutting-edge LTE Advanced technolo- gies. Huawei also commercially launched a 3.5GHz ultra-wideband RRU that provides more than 115 MHz of instantaneous bandwidth to support four carriers. Huawei also commercially launched the eRelay 3.5GHz backhaul solution in the Bahamas. Figure 5 presents Huawei's solution for the smooth evolution from WiMax to TD-LTE to protect the operator investment based on this experience. NSN also recognizes that TD-LTE technology in Bands 42 and 43 in conjunction with increased spectral efficiency and small-cell base stations represents a unique capacity opportunity for addressing the challenge of 1000x mobile broadband traffic growth. NSN has been selected as a TD-LTE vendor by 11 major operators, and to date has deployed eight commercial TD-LTE networks with 15,000 live TD-LTE cells in the 1.9GHz, 2.3GHz and 2.6GHz bands. NSN believes the step to 3.5GHz TD-LTE is not a big technology leap, but timing will depend on end-to-end industry development Figure 5: Smooth Evolution From WiMax to LTE to Protect Investment Source: Huawei HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 13 and expanding the device ecosystem. With 400 MHz in valuable spectrum assets from 3.4-3.8 GHz, most countries will be making their licensing decisions on Bands 42 and 43 soon. NSN is proposing an all-in-one integrated solution (BBU+RRU in one box) with flexible backhaul options to add capacity exactly where it is needed. Hitachi is a Japanese telecom solutions provider that recognizes the importance of 3.5GHz spectrum as the first band offering global assignments of more than 40MHz. Hitachi believes TD-LTE is the best solution for optimizing the mobile data capacity of the 3.5GHz band, given its ability to support asymmetric upload/ download allocations based on system configuration. Hitachi also recognizes the value of using 3.5GHz spectrum with small cells with active antennae, 3D-MIMO and beam-forming to minimize the effect of macrocell interference. Airspan is focused on making 4G OFDM/OFDMA small-cell solutions smarter, scalable, cost-effective and future-proof. With an extensive portfolio of outdoor/ indoor LTE small-cell solutions, Airspan is heavily invested in technologies for interfer- ence management in aggressive frequency reuse scenarios and offers a unique small cell with integrated non-line-of-sight and line-of-sight backhaul. Airspan has also developed a high-performance, low-cost, small-cell solution for 3.5GHz operators wanting to deploy LTE Advanced services using carrier aggregation. Telrad Networks is a leading provider of telecom solutions that acquired Alvarion's BWA division, with an extensive portfolio of infrastructure solutions and a large international installed base of 3.5GHz WiMax networks. Most of the 3.5GHz opera- tors that make up 70 percent of the Telrad WiMax installed base are planning a transition to TD-LTE. Telrad is one of the lead contributors to the development of WiMax Advanced Release 2.2 to support the convergence of WiMax and TD-LTE and offers a distributed Evolved Packet Core (EPC) optimized solution for data- centric mobile and fixed services to enable fixed/mobile convergence on LTE. The availability of terminals supporting the 3.5GHz band is critical, so operators and vendors are starting to work together to increase the global production of low- cost 3.5GHz LTE TDD devices. Several key vendors leading the market for LTE semiconductor solutions with chipsets for both single- and multimode applications made presentations at the GTI 3.5GHz Interest Group Workshop. The following summarizes key points from the presentations made available by selected semiconductor vendors after the workshop: Sequans Communications is a publicly traded, leading chipmaker dedicated to enabling mass-market 4G LTE and WiMax chips to original design manufacturers (ODMs) and original equipment manufacturers (OEMs) worldwide. Sequans has developed an extensive line of ODM products supporting 3.5GHz spectrum, including a dual-mode WiMax/LTE solution to help mobile operators and device makers accomplish a smooth and cost-effective transition from WiMax to LTE. Altair Semiconductor is a privately held, Israel-based global leader of single-mode baseband and RFIC for FDD and TDD LTE semiconductor solutions. Altair shared its insight into the key challenges for 3.5GHz chipset availability and the LTE device ecosystem. Since the 3.5GHz band is wide and not yet harmonized globally, additional bands are expected to be defined. Current filters are based on legacy WiMax filters in the 3.3-3.9GHz range, and specific band filters are expected to be developed as markets mature. Inter-device coexistence between devices in different networks is a key TD-LTE deployment challenge that does not exist in FDD. Altair and its ODM partners are committed to accelerating the 3.5GHz TD-LTE device ecosystem and enabling commercial-grade device introduction this year. HEAVY READING | NOVEMBER 2013 | SPECIAL RESEARCH REPORT | LTE TDD SERVICES IN THE 3.5GHZ BANDS 14 Conclusion Global harmonization of the 3.5GHz spectrum band is critical to supporting a single ecosystem, particularly for chipsets and terminal devices. Many attendees came to Tokyo to help speed up the release of 3.5GHz spectrum, which is critical for unleashing the power of TD-LTE Advanced technologies. Global harmonization of 3.5GHz spectrum in LTE Bands 42 and 43 is also essential to ensure the sharing of the same ecosystem, particularly for chipsets and terminals. The GTI 3.5GHz Interest Group has proposed that 3.5GHz spectrum be released in at least 40MHz blocks to realize the inherent deployment advantages of its wide bandwidth. Many coun- tries are expected to release more 3.5GHz spectrum to promote the development of mobile broadband services using high-spectrum bands. In Japan, the 2.5GHz band is currently shared between SoftBank WCP and the UQ Communications affiliate of KDDI. SoftBank was disappointed when a new block of 2.5GHz spectrum was awarded to competitors KDDI and UQ, as both carriers seek to boost download speeds for mobile broadband devices. As such, SoftBank has a heightened interest in the next large block of spectrum that may become available in Japan. Japan's regulator recently re-farmed the 3.5GHz band by moving studio-transmitter link video services to enable LTE Advanced performance with small-cell deployment and offload capabilities, with a target commercial schedule of 2015. SoftBank predicts that the Japanese government will allocate a large block of spectrum for commercial LTE by 2015. Based on the success of the world's first trial network supporting TD-LTE Advanced technology in the 3.4-3.6GHz band, SoftBank is positioning itself to secure a large portion of this new band. In the U.S., the Federal Communications Commission (FCC) has been working to open up the 3.5GHz band for wireless broadband small-cell deployment via a shared-access system with incumbent licensees. The propagation loss characteris- tics of the 3.5GHz bands make them amenable for high-frequency reuse to enable dense small-cell deployments, and the amount of available spectrum in these bands fares well for broadband quality. In Europe, the CEPT/ECC is working with national regulators to define the preferred TDD or FDD allocation system for accommodating multipoint fixed wireless systems in the 3.4-3.6GHz and 3.6-3.8GHz bands. Subsequent to the last CEPT meeting, more than 90 percent of respondents in CEPT showed their preference for TDD over FDD. Guidelines may soon be issued to synchronize TDD spectrum to avoid restricted blocks and large guard bands. European operators like Bolloré would like their local regulators to adopt the CEPT/ECC PT-1 band plan to release more TDD spectrum in the 3.5/3.6GHz bands. Other key regulatory and technical issues will need to be resolved so operators can fully exploit the use of 3.5/3.6GHz spectrum for TD-LTE Advanced small-cell deployments. In many emerging market countries, the 3.5GHz band has been primarily licensed for fixed BWA, and it is still not clear how these operators will obtain regulatory approval to support TD-LTE services in a WiMax network. Many of these operators are also seeking regulatory reforms that would remove technolo- gy restrictions on its 3.5GHz spectrum license that prevent mobility and backhaul- ing. The next step will be for the GTI and its 3.5GHz operator and vendor ecosys- tem to work with the WiMAX Forum to begin working collaboratively to streamline the regulatory arena especially in emerging markets and smooth the conver- gence of WiMax to TD-LTE Advanced to protect the operator investments.