The telecom sector is witnessing exponential growth in mobile broadband traffic and subscriptions globally, with small- and large-screen data-enabled devices such as smartphones, laptops and tablet computers gaining popularity worldwide. Mobile broadband traffic has been growing at over 100 per cent annually in many markets including both developed and emerging economies. New mobile broadband markets are opening up and the sector is moving towards deploying mobile broadband technologies like Wi-Max and long term evolution time division duplex (LTE TDD). These technologies will provide the quality of service and data rates needed to support the growth of applications such as mobile TV, wireless broadband services and video chat.

LTE and Wi-Max provide comparable performances as both use an internet protocol core and an orthogonal frequency division multiple access air interface as the main technologies. Industry forecasts show strong adoption rates for both Wi-Max 802.16e-2005 (mobile Wi-Max) and LTE, leading to the necessary volumes for driving scale economies. The majority of wireless networks would be shared between the Wi-Max and LTE technology platforms within a decade.

However, since Wi-Max has a two-year headstart, it has reached a more mature state in terms of technology, devices and ecosystem while LTE deployments are likely to take a few years to gain momentum. This gives Wi-Max operators an advantage in terms of a ready network, subscribers and a deployed technology over LTE TDD operators. Wi-Max operators also have the choice of switching to LTE TDD later.

However, with a strong commitment from mobile operators that have deep pockets and a large subscriber base, LTE is set to dominate the mobile broadband market within a few years.

Initially, the coexistence of these technologies seemed appropriate for meeting the increasing demand because LTE focused more on frequency division duplex (FDD) spectrum and Wi-Max on TDD spectrum. However, over the past few years, the growing support for a TDD version of LTE, LTE TDD, has created a more direct competitor for Wi-Max. Interest in LTE TDD originated in China and has spread across the world with many mobile operators attracted by the opportunities of international roaming and using less expensive TDD spectrum to boost capacity in domestic markets. The emergence of LTE TDD is making Wi-Max operators re-evaluate their long-term plans. Even as Wi-Max operators are exploring the opportunities offered by LTE TDD as a complementary technology or an alternative to Wi-Max, the technology continues to witness increased adoption. On the other hand, LTE TDD is still being developed and will take time for deployment beyond core markets like China.

A look at the key trends and developments in the Wi-Max and LTE TDD technology segments across the globe…

Size and growth

With over 600 deployments, 213 device models and 61 types of base stations being certified, the global Wi-Max industry comprised over 13 million subscribers as of December 2010. However, with the top 50 Wi-Max operators accounting for 8.34 million of these subscribers, this is clearly a highly concentrated industry. According to research firm Maravedis, the global broadband wireless access (BWA)/Wi-Max subscriber base is expected to increase to 8.5 million by end-2011, while the LTE consumer base will reach 6.5 million.

According to Maravedis, 58 LTE FDD and three LTE TDD networks will be operational globally by end-2011. Operator commitments for LTE TDD are also likely to increase as several 4G spectrum auctions are scheduled in the first half of 2011 (mainly in Europe). The company expects the number of  LTE FDD and LTE TDD operator commitments to reach 222 and 25 respectively.

While China Mobile, the world’s largest operator by subscribers, is driving the pace of LTE TDD development, the service provider is likely to be pipped to the post in launching the world’s first commercial LTE TDD network by Polish start-up Aero2. The mobile broadband service provider has already awarded an LTE TDD contract to Huawei Technologies and is set to deploy the network in early 2011.

According to analysts at Heavy Reading, India would become the second largest market for LTE TDD after China in the near future. In India, which is a key broadband market, the momentum seems to have shifted to LTE TDD and most Indian BWA licensees are preparing to deploy LTE in the 2.3 GHz TDD spectrum band. According to Heavy Reading, both China as well as India would launch LTE TDD in this band in 2011, followed by Indonesia.

As these are the world’s most populous countries, Heavy Reading and Pyramid Research expects the global LTE TDD subscriber base to increase from 6 million in 2011 to nearly 158 million in 2015, primarily driven by the Asia-Pacific and North American regions. On the other hand, the LTE FDD subscriber base is expected to reach 12 million in 2011 and cross 264 million in 2015, driven largely by operators in West Europe, Japan and the US.

With TDD spectrum allocations, the LTE TDD market will grow in countries  like China, Germany, Malaysia and India.

Trends and developments

While the commercialisation of LTE FDD started with the launch of 11 global networks in 2010, the industry is now turning its attention to LTE TDD. China Mobile’s network trials and the efforts of the 3rd Generation Partnership Project standards body to unify the FDD and TDD variants have spurred the development of this version of LTE.

In February 2011, the Global LTE TDD Initiative (GTI) was launched by China Mobile, Bharti airtel, Softbank Mobile, Vodafone, Clearwire, E-Plus and Aero2. GTI will focus on promoting the development of LTE TDD, the convergence of the LTE TDD as well as FDD modes to maximise economies of scale, and sharing the ecosystem with other TDD technologies such as Japan’s eXtended Global Platform.

While a certain scale for LTE TDD was guaranteed, given the strong support from China Mobile as TD-SCDMA proved to its cost, this is not enough to make LTE TDD a global success. Consequently, China Mobile has considered it important to garner support from other key players. With heavyweights such as China Mobile, Bharti airtel, Softbank Mobile and the Vodafone Group serving over 1.1 billion subscribers at end-2010, GTI is heading in the right direction.

Operators are now looking at deploying hybrid networks, which involve both TDD and FDD, to optimise their spectrum resources in both domains. Companies like Alvarion are also using both LTE TDD and Wi-Max because these use the same spectrum bands and are, therefore, interchangeable in a way that both can be used by the same device.

In the latter half of 2010, Huawei released the first commercially available Wi-Max and LTE TDD single radio access network solution, which enables operators to seamlessly migrate from Wi-Max to LTE TDD networks. The solution comprises a Wi-Max and LTE TDD dual-mode remote radio unit and a dual-mode base band unit, which support the 2.3 GHz, 2.5 GHz and 3.5 GHz mainstream TDD frequency bands.

Wi-Max operators have also started playing a more active role in the LTE TDD standardisation process. In the US, Clearwire, Wi-Max’s poster child, has conducted LTE trials and recorded peak download speeds of 90 Mbps in its initial LTE tests in Phoenix. The results are important as the company’s Wi-Max network provides download speeds of only 3-6 Mbps, with bursts of 10 Mbps. Clearwire has tested a Wi-Max network along with LTE in the 10x10 MHz and 20x20 MHz network configurations, and recorded download speeds of 50 Mbps and 90 Mbps (and upload speeds of 30 Mbps) respectively.

The way forward 

Though some industry experts are of the view that the promise of LTE TDD is denting the future of Wi-Max, the latter’s market is clearly on a strong growth path due to the expansion of existing networks as well as greenfield deployments, a gradually broadening device ecosystem and continued subscriber addition. Even as Wi-Max is facing a few challenges from LTE TDD, service providers including KDDI have stated that LTE would not be sufficient to address capacity issues and that they intend to adopt a broad 4G strategy that includes Wi-Fi and Wi-Max as complementary technologies. Over the long term, developing countries such as India, China, Indonesia, Brazil and Mexico will be the high-growth markets for Wi-Max. This technology will continue to hold its own against LTE TDD even if operators migrate to LTE TDD