TD - LTE

TD - LTE namely td-scdma graphs supplied for publicity is refers to the similarities, td-scdma long-term Evolution. In fact no relationship. TD - LTE is TDD version of LTE technology, the technology is FDDLTE FDD version of LTE technology. The difference is that TDD and FDD is not symmetrical by starting with time frequency is full-duplex and FDD is USES a pair frequency for duplex. Td-scdma is CDMA technology, TD - LTE, cannot docking is OFDM technology.

What is a TD - LTE?

TD - LTE (graphs supplied for our country have similarities) is the core of independent intellectual property international 3G standard td-scdma follow-up Evolution technology, is a specialized applications for mobile high broadband wireless communication standard designed.

TD - LTE industrialization progress:

Under the leadership of the government, China mobile to promote the innovation, which - LTE industrialization and internationalization development.

TD - LTE in standardization with LTE FDD basic synchronization, LTE agreement in 2009 edition (march release Rel 8), 10 years march release second edition (Rel 9), have been frozen. TDD and FDD exists between the two formats high degree of coherence.

TD - mainly includes three characteristics: LTE

TD - LTE as the communication industry transformation period, the important opportunity, mainly includes three features:

1. Contains a number of Chinese patents by China dominated, meanwhile, has been widely international support, become the international standard;

2. Internet speed, can achieve td-scdma technology a few times, make the ubiquity of high-speed Internet become possible;

3. Industry development speed, and other international mobile broadband technology basically achieved, representing the synchronous development of mobile communication industry in the world today the most advanced level.

The preliminary LTE needs

In early November 2004 of the meeting, the 3GPP Quebec 3GPP decided to start the long-term Evolution (3G system graphs supplied for the research project similarities. The world's main operators and equipment manufacturers through the conference, E-mail discussions way, begin to form of LTE system preliminary requirements:

As a kind of advanced technology, LTE in improving peak require the system data rate, community edge rate, spectrum efficiency, and focus on reducing the operation cost and further improve the arrangement, and users can get "Always for Online experience", the need to reduce control and users in the plane of the delay. This system must be able to and existing system (2G / 2.5 G / 3G) coexist.

The existing system made corresponding change

In the wireless access network (RAN) side by CDMA technology will change for more effective against broadband system to multipath interference OFDM (orthogonal frequency division modulation) technology. OFDM technology from 1960s, subsequently developing and perfecting, after the 1990s as signal processing technology development in the digital radio, DSL and wireless LAN and other areas to be widely applied. OFDM technology has the multipath jam, implementation is simple, flexible support different bandwidth, high efficiency support efficient spectrum adaptive scheduling etc, and is recognized as one of the future "4G" reserve technology.

LTE will choose technology

In order to further improve spectrum efficiency, MIMO (multi-input multi-output) technology also become LTE will choose technology. MIMO technologies use multiple antenna systems space channel characteristic, can simultaneously transmit more data flow, thus effectively improve the data rate and spectrum efficiency.

In order to reduce control and customer plane delay, meet low delay (control surfaces delay 100ms, users face less than 5ms) request to delay, the current NodeB - RNC - CN structure must be simplified, RNC as a physical entity will disappear, part of the RNC NodeB will have eNodeB functionality into eNodeB by X2 interface between, on reticular interconnections, access to CN. This system changes will affect change of network architecture, the evolution of SAE (system architecture and also in the 3GPP also for RAN/CN in planning the smooth evolution.

As LTE demand, the evolution of TDD systems with the evolution of FDD system is synchronism.

In June 2005 in France the 3GPP conference, held in datang mobile, joint domestic manufacturer for bibcock is proposed based on the OFDM evolutionary pattern of TDD programs in in Seoul in November the 3GPP working group meeting held by the dominant datang mobile for td-scdma follow-up evolution LTE TDD technical proposal.

To June 2006, feasibility study stage of LTE basic end, norm establishment stage start.

In September 2007, the 3GPP RAN37 meeting, several international operators put forward the joint TYPE2 TDD frame structure support, in November in jeju-do working group meeting on through the LTE TDD fusion technology based on the proposal, which has united the frame continuation of two TDD (standard td-scdma LCR/HCR) mode. 38 times in RAN session in the fusion frame is officially approved, scheme in writing the 3GPP standards.