The research of LTE includes some generally considered important parts, such as the reduction of waiting time, higher user data rate, the improvement of system capacity and coverage, and the reduction of operating costs.
3GPP long term evolution (LTE) project is the largest new technology research and development project initiated by 3GPP in recent two years. This technology based on OFDM/FDMA can be regarded as? Quasi-4G? Technology. The main performance targets of 3GPP LTE project include: providing downlink 100Mbps and uplink 50Mbps peak rates within 20MHz spectrum bandwidth; Improve the performance of users at the edge of the cell; Improve battery capacity; Reduce the system delay, the one-way transmission delay of user plane is less than 5ms, the migration time of control plane from sleep state to active state is less than 50ms, and the migration time from resident state to active state is less than100 ms; Support cell coverage with radius 100Km; It can provide >: 100kbps access service for 350Km/h high-speed mobile users; It supports paired or unpaired spectrum, and can flexibly configure various bandwidths from 1.25 MHz to 20MHz.
Main technical characteristics of LTE
3GPP from? System performance requirements? 、? Network deployment scenario? 、? Network architecture? 、? Business support ability? LTE is described in detail. Compared with 3G, LTE has the following technical features:
(1) The communication rate has been improved, with the downlink peak rate 100Mbps and the uplink 50Mbps.
(2) The spectrum efficiency is improved, and the downlink frequency is 5(bit/s)/Hz, which is 3-4 times that of the R6 version of HSDPA; The uplink is 2.5 (bits/second)/Hz, which is 2-3 times that of the R6 version of HSU- Pa.
(3) With packet domain services as the main target, the overall architecture of the system will be based on packet switching.
(4)QoS guarantee, which guarantees the service quality of real-time services (such as VoIP) through system design and strict QoS mechanism.
(5) The system is flexible in deployment, and can support various system bandwidths between 1.25MHz-20MHz. Pairing? And then what? Not paired? Spectrum allocation. It ensures the flexibility of future system deployment.
(6) Reduce the wireless network delay: the subframe length is 0.5ms and 0.675ms, which solves the problem of backward compatibility, reduces the network delay, and the delay can reach U-plan.
(7) Improve the cell boundary bit rate, and improve the cell boundary bit rate while keeping the current base station position unchanged. For example, MBMS (Multimedia Broadcasting and Multicast Service) can provide a data rate of 1 bit/second/hertz at the cell boundary.
(8) Emphasize backward compatibility and support the cooperative work of existing 3G systems and non-3GPP standard systems.
Compared with 3G, LTE has more technical advantages, such as high data rate, packet transmission, delay reduction, wide-area coverage and backward compatibility.
Application development of LTE
At present, there are three main evolution paths of mobile wireless technology: one is WCDMA and TD-SCDMA, both of which evolve from HSDPA to HSDPA+ and then to LTE. Secondly, CDMA2000 will eventually reach UMB along EV-DO Rev.0/Rev.A/Rev.B (a new scheme recently put forward by Motorola is that CDMA2000 will also evolve to LTE in some way, and 3GPP2 basically gives up UMB scheme); The third is 802. 16m WiMAX routing. Among them, LTE has the most supporters, followed by WiMAX.
LTE is a technology developed by Ericsson, Nokia Siemens, Huawei and other major telecom equipment manufacturers in the world. Alcatel-Lucent and Nortel Networks in CDMA camp also have investments. CDMA has been losing power in recent years. Alcatel-Lucent has reduced its assets related to CDMA technical standards by $3.7 billion in Upper Zhou Chong, and will set up a joint venture with Japanese NEC to develop LTE.
Because Qualcomm has occupied the core technology patents in the 3G era, the LTE camp deliberately engages in OFDM to bypass Qualcomm's major technologies, and Qualcomm's position will definitely be weakened compared with the 3G era; At the same time, despite Qualcomm's lack of interest in UMB technology, the company also announced in Barcelona that it will launch a multimode LTE chipset in 2009, and Qualcomm will continue to make profits in this field.