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TD-LTE

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Time-Division Long-Term Evolution (TD-LTE), also referred to as Long-Term Evolution Time-Division Duplex (LTE TDD),[1] is a 4-G mobile-telecommunications technology and standard co-developed, since late 2007, by Datang Telecom, China Mobile, Huawei, ZTE, Nokia Siemens Networks, Alcatel Shanghai Bell, Qualcomm, ST-Ericsson, Leadcore, etc. It is one of two variants of the 3GPP Long Term Evolution (LTE) technology, the other being Frequency-Division Long-Term Evolution (FD-LTE or LTE FDD). Likewise, TD-LTE-Advanced is an LTE Advanced time-division variant, an evolutionary upgrade version of TD-LTE.

Contents

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.[2]

Deployments and coverages

  • In early 2011, China Mobile invested CNY 1.5 billion on the '6+1 Scheme', in which large-scale TD-LTE field trial was conducted in 6 cities including Shanghai, Guangzhou, Shenzhen, Hangzhou, Nanjing, and Xiamen.[3] Each of the cities deployed around 500 TD-LTE femtocell base-stations. A demonstration network was set up in Beijing. Outside the mainland, China Mobile built a TD-LTE network in Taipei, for testing purposes for the local GSM operator Far EasTone, .[4]
    • As of September 2011, China Mobile has sealed agreements with 32 international telecom carriers, for launching 27 TD-LTE trial networks.[5]
  • On 10 April 2012, Airtel launched 4G services using TD-LTE technology in Kolkata, becoming the first company in India to offer 4G services. Since the initial launch, Airtel also launched 4G in Bangalore and Pune.[6]

Technical highlights

TD-LTE offers asymmetric use of unpaired spectrum.. In "unpaired spectrum" transmissions travel in both directions on the same frequency band. It is distinct from "paired spectrum," where two frequencies are allocated, one for the transmit channel and the other for the receive channel (hence "Frequency Division.") "Time Division" means the receive channel and the transmit channel take turns (i.e. divide the time between them) on the same frequency band. In this instance, "asymmetric" means that more time-slots are allocated to data going down to the phone than coming back up from the phone.[7] The usage patterns of the future (fewer phone calls, more Internet) are asymmetric.

The frequency bands used by TD-LTE are 3.4–3.6 GHz in Australia[8] and UK,[9] 2.57−2.62 GHz in the US[10] and China,[11] 2.545-2.575 GHz in Japan,[12] and 2.3–2.4 GHz in India[13] and Australia.[8] The technology supports scalable channel bandwidth, between 1.4 and 20 MHz.[14] A typical range is up to 200 metres (660 ft) indoors on a 2.57–2.62 GHz radio frequency link.[15]

Equipment/component availability

Vendors that announced end-user support include Nokia and ZTE. Nokia announced a TD-LTE/FD-LTE/HSPA+/TD-SCDMA/EDGE multi-mode netbook based on the ST-Ericsson M7400 MPSoC.[16] ZTE announced V2, a TD-LTE/TD-SCDMA/GSM multi-mode dual-standby smartphone.[17]

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 announced the Warp drive 5000, a TD-LTE/FD-LTE dual-mode baseband processor[18] and Sequans Communications which announced the SQN3010, a similar chip.[19]

References

  1. ^ Kan, Michael (19 August 2011). "ZTE, China Mobile Demo 4G LTE TDD Phone". cio.com. Retrieved 26 September 2011.
  2. ^ "中国3G通信演进给4G留路". 人民网. April 2008.
  3. ^ "Mobile 4G: China Mobile Rolling out TD-LTE Trials", GoMoNews, Jan. 2011.
  4. ^ "China Mobile and Far EasTone Ink Deal on TD-LTE for Taiwan", PCWorld, Apr. 2011.
  5. ^ "China Mobile Gets US Boost", China Daily, Sep. 2011.
  6. ^ "India’s First 4G Service Goes Live in Kolkata Courtesy Airtel". telecomtalk.info. Retrieved 16 April 2012.
  7. ^ "LTE FDD, TDD, TD-LTE Duplex Schemes". Radio-Electronics.com.
  8. ^ a b "Australia: WiMAX to TD-LTE". DailyWireless. July 2011.
  9. ^ "UK Broadband: UK Broadband goes live". Rethink Wireless. March 2012.
  10. ^ "Clearwire, Sprint seek 3GPP standard for TDD-LTE in 2.6GHz band". LTEWorld. March 2010.
  11. ^ "工信部敲定TD-LTE频率 2570M~2620MHz". 光通讯网. April 2011.
  12. ^ "Wireless City Planning株式会社に係る特定基地局の開設計画の変更認定". Ministry of Internal Affairs and Communications. June 2011.
  13. ^ "Airtel to Contract Multiple Vendors for Its BWA Spectrum Deployment?". TeleGeography. October 2011.
  14. ^ "HSPA+与LTE技术兼容问题". 电子工程世界. August 2011.
  15. ^ "TD-LTE频率之困迫在眉睫". 中国移动通信研究院. September 2011.
  16. ^ "Nokia Booklet 3G 变种搭上 TD-LTE 于北京现身，可惜只是测试机". Engadget. September 2011.
  17. ^ "中興通訊全球首款TD-LTE亮相北京通信展". 中華網數位頻道. September 2011.
  18. ^ "創毅推40納米TD-LTE終端基帶芯片WarpDrive5000". 南方網. September 2011.
  19. ^ "Sequans公司發佈首款LTE晶片". 無線電技術. March 2010.

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