Carriers Back LTE TDD for 4G Through New Initiative
Mobile carriers including China Mobile, Bharti Airtel and Vodafone have launched a new initiative to promote the 4G (fourth-generation) network technology LTE TDD as a global standard.
LTE TDD (Long-Term Evolution Time-Division Duplex), also known as TD-LTE in China, is one of two LTE variants that both offer higher data speeds than today's 3G (third-generation) networks. With TDD, operators can tune their network to allow more capacity for downloads than for uploads, for example. In the other variant, FDD (frequency division duplex), networks typically must allocate the same bandwidth for downloads as for uploads.
The TDD supporters kicked off their initiative this week at Mobile World Congress in Barcelona. Other backers include Japan's Softbank Mobile, Clearwire and Germany's E-Plus.
China Mobile, the country's largest mobile carrier at 584 million customers, has been the major supporter of TD-LTE. At the same time, China's government has already begun large-scale trials of the technology and is researching the development of commercial equipment for TD-LTE networks.
But interest in LTE TDD has been growing among other mobile carriers elsewhere, say analysts and network equipment suppliers. On Wednesday, China's ZTE said it had secured 18 contracts to build trial and commercial LTE TDD networks in Europe, the former Soviet republics and Asia.
The newly announced initiative is meant to develop the "ecosystem" for the LTE TDD technology and promote it. This could lead to the faster development of lower cost LTE TDD mobile phones, as well as the fostering of a developer community to build apps and content for such devices, say its promoters.
The initiative contrasts with the way China Mobile deployed its 3G network, said CW Cheung, a consulting director for research firm Ovum. China Mobile uses a 3G standard called TD-SCDMA (Time-Division Synchronous Code Division Multiple Access), which is a homegrown technology supported by China's government. The TD-SCDMA standard is only used in China and was developed as a way to reduce the nation's dependency on foreign technologies.
But its promotion has posed a challenge for China Mobile since the technology is not used globally. Many of the most popular smartphones such as the iPhone cannot be used on a TD-SCDMA network and instead would have to be redesigned to work on it.
This new initiative, however, represents "an important milestone" moving on from the Chinese government and China Mobile deploying LTE TDD technology, Cheung said: "They're now not just focusing on standards and technologies, but more on ecosystem development, partnership, public relationship."
The initiative also seeks to promote the convergence of LTE TDD with LTE FDD. Carriers have expressed interest in using both standards on their 4G networks as a way to maximize their capacity.