4G Network Standard: Introduction and Technical Differences of TD-LTE and FDD-LTE (1)
China Mobile will adopt the TD-LTE standard with independent intellectual property rights. In addition to TD-LTE, one of the 4G standards widely adopted in the world is FDD-LTE. This article will introduce these two 4G network modes to you.
4G network
4G is the fourth generation of mobile phone mobile communications standards (English: fourth generation of mobile phone mobile communications standards, abbreviated as 4G), and it is also an extension after 3G. This set of wireless communication standards, from the perspective of technical standards, according to the definition of ITU, the static transmission rate reaches 1Gbps, and the user can reach 100Mbps in the high-speed mobile state, which can be used as one of the 4G technologies.
4G network has the following two standards:
LTE Advanced is an enhancement of LTE and is fully backward compatible with LTE. It is usually done through a software upgrade over LTE, and the upgrade process is similar to upgrading from WCDMA to HSPA. The peak rate is 1Gbps downstream and 500Mbps upstream. It is the first batch of 4G standards recognized by the International Telecommunication Union, and in fact the only mainstream 4G standard.
WiMAX-Advanced is an upgraded version of Global Interoperability Microwave Access, namely IEEE 802.16m, which is an enhancement of WiMAX. It is dominated by Intel in the United States. The maximum rate of receiving downlink and uplink can reach 300Mbps, and it can receive up to 1Gbps at a stationary fixed point. It is also a 4G standard recognized by the International Telecommunication Union. However, with the withdrawal of Intel in 2010, WiMAX technology was gradually abandoned by operators and began to upgrade equipment to LTE. The WiMAX Forum also included TD-LTE in the WiMAX 2.1 specification in 2012.
The normal evolution form of 4G network
Among them, LTE (Long Term Evolution, long term evolution technology) technology is the evolution of 3G, usually called 3.9G, including two duplex modes of TDD and FDD, and TD-LTE is the TDD version of LTE. And FDD-LTE is the FDD version of LTE. LTE is a project started by 3GPP in 2004. It is divided into FDD-LTE and TD-LTE. The former is dominated by Europe and the United States, and the latter is dominated by my country. In 2007, the Ministry of Industry and Information Technology named TDD-LTE as TD-LTE.
TD-LTE
TD-LTE (Time Division Long Term Evolution, Time Division Long Term Evolution) is a communication technology and standard based on 3GPP Long Term Evolution (LTE), and belongs to a branch of LTE. The technology is jointly developed by Shanghai Bell, Nokia Siemens Networks, Datang Telecom, Huawei Technologies, ZTE, China Mobile, Qualcomm, ST-Ericsson and other companies.
TD-LTE is also called LTE TDD, and TDD refers to Time-division duplex. It is worth noting that Chinese media generally promote TD-LTE as a domestic standard in China, but in fact its technology belongs to LTE (Long Term Evolution). The Chinese government and enterprises are the main drivers of TD-LTE. The upgraded version of TD-LTE is called TD-LTE Advanced, which is the real 4G standard.
FDD-LTE
FDD (Frequency Division Duplex) is one of the duplex modes of the LTE technology, and LTE applying the FDD (Frequency Division Duplex) type is FDD-LTE. Due to factors such as differences in wireless technologies, different frequency bands used, and the interests of various manufacturers, the standardization and industrial development of FDD-LTE are ahead of TDD-LTE. FDD-LTE has become the most widely used 4G standard in countries and regions in the world, with the most diverse types of terminals.
FDD-LTE is adopted by operators in many countries
The characteristic of the FDD mode is that the system receives and transmits on two symmetrical frequency channels separated (up and down frequency interval 190MHz), and uses the guaranteed frequency band to separate the receive and transmit channels. The advantage of the FDD mode is that it adopts technologies such as packet switching, which can break through the bottleneck of the second-generation development, realize high-speed data services, improve spectrum utilization, and increase system capacity.
