Time-Division Long-Term Evolution
Encyclopedia
Time-Division Long-Term Evolution (TD-LTE), also referred to as Long-Term Evolution Time-Division Duplex (LTE TDD), is China's home-grown 4-G mobile-telecommunications technology and standard co-developed, since late 2007, by Datang Telecom, China Mobile
China Mobile
China Mobile Limited is a Chinese state-owned telecommunication company that provides mobile voice and multimedia services through its nationwide mobile telecommunications network, the largest of its kind in the world...

, Huawei
Huawei
Huawei is a Chinese multinational networking and telecommunications equipment and services company headquartered in Shenzhen, Guangdong, China...

, ZTE
ZTE
ZTE Corporation formerly Zhongxing Telecommunication Equipment Corporation is a Chinese multinational telecommunications equipment and systems company headquartered in Shenzhen, China...

, Nokia Siemens Networks
Nokia Siemens Networks
Nokia Siemens Networks is a global data networking and telecommunications equipment company headquartered in Espoo, Finland. It is a joint venture between Nokia of Finland and Siemens of Germany...

, Alcatel
Alcatel-Lucent
Alcatel-Lucent is a global telecommunications corporation, headquartered in the 7th arrondissement of Paris, France. It provides telecommunications solutions to service providers, enterprises, and governments around the world, enabling these customers to deliver voice, data, and video services...

 Shanghai Bell, Qualcomm
Qualcomm
Qualcomm is an American global telecommunication corporation that designs, manufactures and markets digital wireless telecommunications products and services based on its code division multiple access technology and other technologies. Headquartered in San Diego, CA, USA...

, ST-Ericsson
ST-Ericsson
ST-Ericsson is a global wireless platform and semiconductor supplier to four of the top five mobile handset manufacturers. ST-Ericsson is a 50/50 joint venture of Ericsson and STMicroelectronics established on February 3, 2009...

, Leadcore, etc. It is one of two variants of the 3GPP Long Term Evolution
3GPP Long Term Evolution
3GPP Long Term Evolution, usually referred to as LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using new modulation techniques...

 (LTE) technology, the other being Frequency-Division Long-Term Evolution (FD-LTE or LTE FDD). Likewise, TD-LTE-Advanced is an LTE Advanced
LTE Advanced
LTE Advanced is a preliminary mobile communication standard, formally submitted as a candidate 4G system to ITU-T in late 2009, was approved into ITU, International Telecommunications Union, IMT-Advanced and expected to be finalized by 3GPP in early 2011...

 time-division variant, an evolutionary upgrade version of TD-LTE.

History

The TD-LTE project was approved on 26 December 2007, at the state council executive meeting of the New Generation Broadband Wireless Mobile Communication Networks, along with TD-SCDMA
TD-SCDMA
Time Division Synchronous Code Division Multiple Access or UTRA/UMTS-TDD 1.28 Mcps Low Chip Rate , is an air interface found in UMTS mobile telecommunications networks in China as an alternative to W-CDMA. Together with TD-CDMA, it is also known as UMTS-TDD or IMT 2000 Time-Division .The term...

.

Deployments and coverages

In early 2011, China Mobile has invested CNY 1.5 milliard on the '6+1 Scheme', in which large-scale TD-LTE field trial has been conducted in 6 cities including Shanghai
Shanghai
Shanghai is the largest city by population in China and the largest city proper in the world. It is one of the four province-level municipalities in the People's Republic of China, with a total population of over 23 million as of 2010...

, Guangzhou
Guangzhou
Guangzhou , known historically as Canton or Kwangchow, is the capital and largest city of the Guangdong province in the People's Republic of China. Located in southern China on the Pearl River, about north-northwest of Hong Kong, Guangzhou is a key national transportation hub and trading port...

, Shenzhen
Shenzhen
Shenzhen is a major city in the south of Southern China's Guangdong Province, situated immediately north of Hong Kong. The area became China's first—and one of the most successful—Special Economic Zones...

, Hangzhou
Hangzhou
Hangzhou , formerly transliterated as Hangchow, is the capital and largest city of Zhejiang Province in Eastern China. Governed as a sub-provincial city, and as of 2010, its entire administrative division or prefecture had a registered population of 8.7 million people...

, Nanjing
Nanjing
' is the capital of Jiangsu province in China and has a prominent place in Chinese history and culture, having been the capital of China on several occasions...

, and Xiamen
Xiamen
Xiamen , also known as Amoy , is a major city on the southeast coast of the People's Republic of China. It is administered as a sub-provincial city of Fujian province with an area of and population of 3.53 million...

. Each of the cities has been deployed with around 500 TD-LTE femtocell
Femtocell
In telecommunications, a femtocell is a small cellular base station, typically designed for use in a home or small business. It connects to the service provider’s network via broadband ; current designs typically support 2 to 4 active mobile phones in a residential setting, and 8 to 16 active...

 base-stations. Besides, a demonstration network has been set up in Beijing
Beijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...

. Outside the mainland, China Mobile has also built a TD-LTE network in Taipei
Taipei
Taipei City is the capital of the Republic of China and the central city of the largest metropolitan area of Taiwan. Situated at the northern tip of the island, Taipei is located on the Tamsui River, and is about 25 km southwest of Keelung, its port on the Pacific Ocean...

, for the local Far EasTone, for testing purposes.
, China Mobile has sealed agreements with 32 international telecom carriers, for enabling the launch of 27 TD-LTE trial networks.

Technical highlights

TD-LTE offers asymmetric use of unpaired spectrum. It allocates separate channels for outward and return signals, emulating full-duplex transmission over a half-duplex communication link.

The frequency bands used by TD-LTE are 3.4–3.6GHz in Australia, 2.57−2.62GHz in the US and China, and 2.3–2.4GHz in India and Australia. The technology supports scalable channel bandwidth, between 1.4 and 20MHz. A typical range is up to 200 metres (656.2 ft) indoors on a 2.57–2.62GHz radio frequency link.

Equipment/component availability

Vendors which announced end-user support include Nokia
Nokia
Nokia Corporation is a Finnish multinational communications corporation that is headquartered in Keilaniemi, Espoo, a city neighbouring Finland's capital Helsinki...

 which announced a TD-LTE/FD-LTE/HSPA+/TD-SCDMA
TD-SCDMA
Time Division Synchronous Code Division Multiple Access or UTRA/UMTS-TDD 1.28 Mcps Low Chip Rate , is an air interface found in UMTS mobile telecommunications networks in China as an alternative to W-CDMA. Together with TD-CDMA, it is also known as UMTS-TDD or IMT 2000 Time-Division .The term...

/EDGE
Edge
- Aviation :* Leading edge, a line connecting the forward-most points of a wing's profile* Trailing edge, the rear edge of the wing* Zivko Edge 540, an aerobatic aircraft- Mathematics, science and technology :...

 multi-mode netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

 based on the ST-Ericsson
ST-Ericsson
ST-Ericsson is a global wireless platform and semiconductor supplier to four of the top five mobile handset manufacturers. ST-Ericsson is a 50/50 joint venture of Ericsson and STMicroelectronics established on February 3, 2009...

 M7400 MPSoC
MPSoC
The multiprocessor System-on-Chip is a system-on-a-chip which uses multiple processors , usually targeted for embedded applications...

 and ZTE
ZTE
ZTE Corporation formerly Zhongxing Telecommunication Equipment Corporation is a Chinese multinational telecommunications equipment and systems company headquartered in Shenzhen, China...

 which announced V2, a TD-LTE/TD-SCDMA/GSM multi-mode dual-standby smartphone
Smartphone
A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...

.

Apart from the ST-Ericsson M7400 MPSoC mentioned above, other vendors which announced chipset support include Innofidei, which together with the Hong Kong Applied Science and Technology Research Institute
Hong Kong Applied Science and Technology Research Institute
The Hong Kong Applied Science and Technology Research Institute was founded by the Government of Hong Kong SAR in 2000 with a mission to enhance Hong Kong’s competitiveness in technology-based industries through applied research....

 announced the Warp drive 5000, a TD-LTE/FD-LTE dual-mode baseband processor
Baseband Processor
A baseband processor is a device in a smartphone that manages all the radio functions . This may not include wi-fi and/or bluetooth...

and Sequans which announced the SQN3010, a similar chip.
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