Technology: Focus on LTE-TDD

With the completion of the 3G and broadband wireless access (BWA) spectrum auctions, the sector is gearing up to replicate the success of mobile telephony in broadband. The potential of BWA technologies is evident from the fact that the auctions fetched the government over seven times the reserve price per block. tele.net recently organised a conference, ?BWA in India?, to provide a platform to discuss the potential and challenges associated with these services. The following section on Technology: Focus on LTE-TDD brings forward the views of  Sanjoy Sharma, Director, Sales, Alcatel- Lucent, India; Dr Lakshminath Reddy Dondeti, Director, Engineering, Technical Standards, Qualcomm India & South Asia and Sridhar Vadlamudi, Head, LTE, Ericsson India…

Sanjoy Sharma, Director, Sales, Alcatel- Lucent, India

With the advent of next-generation technologies in the country, the data needs of telecom subscribers are increasing rapidly. While the period between 1995 and 2010 was dominated by 2G technologies, 3G and 4G technologies are set to witness a major uptake in India in the future. This is going to result in a significant addition to the existing wireless data traffic, thereby driving the need for network transformation.

From 2008 to 2013, data traffic is expected to increase 17 times while data revenues will be 1.8 times their current value. Voice and SMS will continue to drive ARPUs in the coming years, though the contribution from data will increase.

The Indian telecom market is evolving towards broadband access. Globally, users are shifting rapidly towards wireless broadband and the new generation of devices present in the market is set to facilitate this transition. New applications proliferating in the market, thanks to the advent of next-generation technologies will need high bandwidth access.

Looking at global trends, AT&T has seen its wireless data traffic grow by a factor of 18 during the past two and a half years, while voice traffic has grown only by a factor of 2. The carrier?s wireless data traffic has increased by 4,932 per cent during the past 12 quarters. In the span of a year (November 2007-December 2008), the UK saw its data traffic grow ten times after launching HSPA+ technology. Verizon Wireless?s data traffic has doubled each year since 2007, while in Hong Kong, the wireless average data usage per user per month grew four times and the total usage by six times.

This boom in data traffic will be the key driver for long term evolution (LTE) technology. There are many reasons favouring the adoption of LTE. With a maximum theoretical download speed of 326 Mbps, it is built for mobility and capacity, and offers a 10 millisecond round trip time. These features ensure a high quality of experience for the end-user. LTE also offers a wide spectrum and bandwidth range and can be smoothly integrated with CDMA, GSM and W-CDMA technologies. Its cost-effective IP architecture and transport make LTE a flexible access technology, which can provide a solution to major challenges faced by operators.

The market for LTE is currently driven by the 3rd Generation Partnership Project (3GPP) operators. There are two types of LTE technologies: LTE frequency division duplex (FDD) and LTE time division duplex (TDD). Trials for LTE-FDD, which is the older of the two, were conducted prior to its commercial launch. After successful trials, the technology was commercially launched in 2010 by major operators in Asia (NTT DOCOMO) and North America (Verizon). Initial deployments by these operators have focused on ?Hot Zone? areas to maximise access to high data users. In Europe and Asia, 2.6 GHz and 1800 MHz spectrum will dominate deployments; while in the US, the focus will be on 700 MHz and advanced wireless services.

LTE-TDD, which is a newer technology, is being led by the China Mobile Communications Corporation (CMCC). This technology is expected to be a next-generation broadband network that will replace GSM and TD-SCDMA. The Unique Global Alignment pact between Vodafone, CMCC and Verizon is set to promote the success of LTE-TDD ecosystems.

LTE is the single market standard for 4G; it also forms the common evolution path for most other existing technologies. All technologies like GSM/UMTS, GSM/  EDGE, TD-SCDMA, 1xRTT, HSPA+ and UMTS/HSPA have an upgrade path to LTE. Other compelling reasons for the adoption of LTE include low latency and high peak throughput rates. Low latency enables a fast channel for adaptation, thus allowing high speed applications, while high peak throughput enables the use of content-rich applications over LTE. Also, as per Alcatel-Lucent?s trial data, LTE facilitates an average downlink throughput of 20-25 Mbps on 10 MHz in real conditions and an average uplink throughput of 10 Mbps on 10 MHz in real conditions. It also delivers a high quality of service (QoS) to ten times more users than the current 3G networks.

LTE technology has huge potential. This is evident from the rollout plans of global operators too. Verizon Wireless intends to launch 25 to 30 commercial LTE markets by end-2010 and double this number within 15 months of the launch. AT&T Mobility will launch commercial LTE service by mid-2011 and will cover between 70 million and 75 million points of presence by the end of next year.

Sridhar Vadlamudi, Head, LTE, Ericsson, India

Global broadband usage is set to witness a sizeable uptake in the near future. Currently, WCDMA/HSPA technology has a presence in mass markets, covering 0.4 million broadband users while GSM/EDGE technology has the largest coverage with 3.5 billion users. Launched in 2009, LTE is the latest technology for broadband access.

Ericsson has a vision of 100 per cent broadband penetration. The company forecasts that it will have more than 6 billion broadband users worldwide by 2014 and 50 billion users by 2020. The key drivers for the growth of broadband penetration will be safety, quality of life, entertainment, increasing productivity, new revenue streams, etc. The future envisages a world with intelligent transportation systems, smart grids, online healthcare and more. Broadband ubiquity and the declining cost of connectivity will be the key enablers for this kind of growth.

LTE is emerging as the preferred broadband technology worldwide. The key advantages of LTE over other technologies are a wider pipe, self-organising networks, all-IP architecture and economies of scale. All in all, the total cost of ownership for LTE is also fairly low. As of now, 101 LTE deployments have been planned or are in progress in 41 countries across the globe and 22 LTE networks are likely to start commercial service soon. Apart from this, 31 operators are currently engaged in various LTE trials globally.

TeliaSonera, a telecom service provider in the Nordic and Baltic countries, became the first operator in the world to launch 4G/LTE services for its customers in Stockholm, Sweden, and Oslo, Norway. A survey conducted by TeliaSonera after 100 days of operation showed that after the deployment of LTE, 26 per cent of the subscribers were working more on their mobiles, 23 per cent were able to download larger files, 19 per cent were watching online TV and stream movies while 16 per cent had begun surfing the web more. Thus, the deployment of new technology has resulted in an improved user experience.

Verizon has also deployed LTE on 10 MHz FDD in the 700 MHz band. It conducted a data-only launch in Boston and Seattle in early 2010 and is in the process of conducting similar launches in 25 to 30 cities covering 100 million points of presence. This launch will be followed by a voice-plus-data launch in 2011. The first LTE smartphones will be available in the market by mid-2011. The company has taken several initiatives to support LTE uptake. It has established an open development forum for LTE device testing and has initiated an LTE Venture Forum involving venture capital funds.

On the Indian front too, LTE-TDD trials have already begun. The first data call was made on July 1, 2010 on the BWA band with TDD configuration. A peak throughput of 81 Mbps downlink has been achieved and multiple applications like YouTube and live TV have been demonstrated. LTE-TDD ? which has a strong 3GPP support, facilitates interworking with other technologies and has a lower total cost of ownership ? is being seen as the perfect technology for BWA in India.

Dr Lakshminath Reddy Dondeti, Director, Engineering, Technical Standards, Qualcomm India and South Asia

When the industry looks at technology choices, it generally considers what is available and what has been incumbent. In the Indian context, BWA spectrum is what is available and the technology choices are between Wi-Max and LTE. According to Qualcomm, LTE is the only viable choice.

The problem at present is how to provide wireless broadband access to a billion Indians in the most feasible and sustainable manner. We have EVDO deployments, which is the currently available mobile broadband technology, while HSPA is still coming up. In India, we have certain challenges such as the scarce availability of spectrum. Therefore, India cannot be compared to other countries where spectrum is not a big constraint. Here, we have two carriers in a region and 1.25 MHz of spectrum. Globally, there are countries with as many as eight carriers with 1.25 MHz of spectrum. With the high density of population in India, this problem of scarce spectrum becomes even more severe. Thus, we need to take a focused look at how to optimise the available spectrum.

Our analysis shows that the best way forward is to focus on 3G and LTE. The biggest question that arises is the readiness of LTE as a technology for immediate use. The current status shows that LTE could be adopted by operators,  as LTE trials are taking place across the country with several vendors and Qualcomm itself is conducting many trials. Commercially, the infrastructure will be available from the first quarter of 2011. Qualcomm has already carried out LTE-TDD mobility demonstrations before end-2010 while LTE to 3G EVDO and HSPA interworking trials will be conducted in the first half of 2011. LTE compatible dongles and tablets will be made available in the first and second half of 2011 respectively.

The final issue is the advantages and challenges that the industry faces while making this technology choice. It is not easy to offer the end-user an up-to-the-mark QoS when it comes to mobile broadband. Thus, the industry needs to look at the actual deployment experience and the economies of scale that can be achieved with LTE.

There are many positives of using LTE for BWA. LTE leverages the new and wider spectrum. A 40 per cent overhead is experienced in 1.4 MHz while it is 25 per cent in 20 MHz. This results in 25 per cent better relative performance in 20 MHz as compared to 1.4 MHz. Also, LTE is a parallel evolution path to 3G. It provides an evolution path for all the existing technologies. LTE-TDD also complements 3G in boosting data services.

Looking at international trends too, operators across the globe are choosing LTE. As many as 156 operators are investing in LTE in 64 countries. There is a commitment of more than 113 commercial LTE network deployments in 46 countries and an additional 43 pre-commitment trials are under way. The majority of operators globally are committed to combining 3G and LTE.