High-speed, low-latency, global universal standard, suitable for symmetric and asymmetric spectrum-LTE has become one of the fastest growing wireless communication technologies in the world because of its various technical advantages. The latest data from GSA in October shows that there are currently 23 LTE TDD networks commercially available in the world, and another 60 LTE TDD networks are under construction or deployment. It is worth noting that 11 of the 23 LTE TDD networks were launched by operators who have deployed LTE FDD. This includes China Mobile (Hong Kong), Softbank (Japan) and Russian MTS.
In addition, more and more terminals support LTE and 3G multi-mode. At present, it seems that because FDD is deployed earlier, it has achieved maturity and success in terminal scale. TDD terminals are launched late, but due to the commonality of technology and products, TDD will benefit from the scale of FDD deployment, and Qualcomm is the representative Of leading chip companies have announced that their LTE chipset supports FDD and TDD at the same time many years ago. According to statistics, there are currently nearly one hundred terminals worldwide that support both LTE FDD and TDD to support operators' own network needs and global roaming needs. The recent large-scale procurement of 200,000 LTE TDD terminals initiated by China Mobile has specifically raised the demand for 5 modes and 10 frequencies, which will inevitably lead to a significant increase in this proportion.
FDD / TDD technology common
LTE is a global standard based on the technical specifications published by 3GPP. Single carrier FDMA is used for uplink and OFDMA is used for downlink. Both paired and unpaired spectrum deployments are applicable. The LTE standard supports two duplex modes, FDD for paired spectrum, and TDD for unpaired spectrum. Based on the experience of managing 3G networks, in order to avoid market fragmentation, leading global operators have promoted LTE as a universal standard from the beginning to support FDD and TDD modes, with only very small necessary differences between the two modes. Therefore, the similarity shared between the two models exceeds 90%.
In terms of networking, China Mobile has deployed a hybrid FDD / TDD network in Hong Kong. Recently, this operator has also proposed on multiple occasions that the integrated development of 4G LTE with TDD and FDD will bring unprecedented development opportunities to the entire industry chain. Huang Yuhong, vice president of China Mobile Research Institute, said, "China Mobile put forward a goal when developing TD-LTE (LTE TDD): convergence, synchronization, and internationalization. The realization of FDD and TDD is the goal. In Hong Kong, we have achieved The integration of FDD and TDD. "Wen Ku, director of the Technology Department of the Ministry of Industry and Information Technology, also said that the communications industry has entered the LTE era. FDD and TDD are two different technologies that are like two members of a family. . Earlier, Dr. Paul Jacobs, Chairman and CEO of Qualcomm, also said, "As a global standard, LTE TDD / FDD will work together to promote industrial innovation."
LTE gains global ecosystem support
In the field of standards, major global companies and operators covered by the 3GPP organization have contributed to the development of LTE standards. The contribution of most enterprises to the LTE standard can be equally used in FDD and TDD modes. LTE has the inherent tight interoperability of TDD / FDD and realizes seamless interworking with 3G. Currently, seamless interworking of LTE FDD and TDD data services has been achieved; in the future, a more powerful combination of LTE FDD and TDD will include the aggregation of spectrum from two modes to achieve higher data rates and throughput.
It is understood that Qualcomm, Ericsson, Huawei, ZTE and other enterprises have expressed support for the integrated development of LTE TDD and LTE FDD on different occasions. Taking Qualcomm as an example, starting from the first generation of LTE products, all its LTE chipsets support both LTE FDD and LTE TDD, and has launched its third-generation Gobi LTE / 3G multimode modulation and demodulation, supporting LTE enhanced (LTE Version 10) and HSPA + version 10, supporting both FDD and TDD. Qualcomm has conducted extensive cooperation with many well-known operators worldwide. In China, Qualcomm and China Mobile have a good tradition of cooperation. Recently, Dr. Paul Jacobs, Chairman and CEO of Qualcomm, also said at the China Telecom Summit Forum, "Qualcomm will fully support the development of the CDMA2000 ecosystem with advanced LTE solutions."
3G and LTE evolve together
According to the picture outlined in the "Broadband China" Strategy and Implementation Plan, the penetration rate of 3G / LTE users will reach 85% in 2020, with a total number of 1.2 billion users. LTE basically covers urban and rural areas. It is worth noting that the 1.2 billion users referred to in the plan are "3G / LTE", not just 4G LTE users. From this perspective, LTE will complement the existing 3G services for a long period of time in the future to ensure a consistent user experience and wide coverage.
From a technical point of view, LTE is an optimized mobile OFDMA (downlink) / single carrier FDMA (uplink) solution, which continues the excellent mobility and high frequency band efficiency of 3G. It uses the new, larger-bandwidth spectrum to increase the data capacity of densely populated urban areas. At the same time, 3G and its evolution technologies will continue to provide ubiquitous broadband coverage and voice services outside the LTE area. In other words, HSPA + and EV-DO version B are the most cost-effective evolution route for existing, reallocated and new discontinuous frequency bands. Not only can HSPA + have the same capacity as LTE with the same number of antennas and bandwidth, but it can also make full use of the operators' existing investments.
According to statistics, most of the LTE smartphones released so far support LTE / 3G multi-mode. Take the newly released Samsung Galaxy S4 LTE-A mobile phone as an example. This mobile phone supports LTE Advanced / LTE / WCDMA / GSM multi-mode, and the peak downlink speed can reach 150Mbps. It adopts the Snapdragon 800 series processor, which integrates Qualcomm Third-generation 4G LTE modem-supports CDMA2000 (1X, DO), GSM / EDGE, WCDMA, TD-SCDMA and LTE (LTE-FDD and LTE-TDD) world models, and supports HSPA + version 10 and LTE Advanced. The Japanese operator NTT Docomo recently released the latest smartphones and tablets from 2013 to 2014 winter and spring. All 10 models use the Snapdragon 800 processor and support LTE Advanced / 3G multimode.
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