LTE "Core" Observation Series Reports Core: Supports Voice TD-LTE Multimode Terminals or Mature Next Years

“The rise of a new industry is a very good opportunity for manufacturers. For companies like Lianxin who always pay attention to key technologies in LTE core, they should seize this opportunity.” Lianxin CEO Sun Yuwang accepts “China Electronics” "Reporter" said in an interview, "From the current stage, the obstacles that affect TD-LTE commercial use are more concentrated in terminal chips and terminal products. For example, high power consumption and insufficient stability include complete multimode support. There is still some way to go to reach the commercial level."

At present, TD-LTE adopts data cards as the industry's first manufacturer to launch TD-SCDMA/TD-LTE dual-mode chips. Lianxin launched the dual-mode chip LC1760 in December 2010 and is participating in TD-China Mobile. One of the three chip manufacturers that tested in the second phase of the LTE scale technology test, the dual-mode data card based on the LC1760 chip has reached the downlink rate of 59M under the current network test.

On May 10 this year, Lianxun released a TD-LTE/LTE FDD/TD-HSPA/GGE multimode chip LC1761 and simultaneously launched a TD-LTE/LTE FDD dual-mode baseband chip LC1761L. The chip is the second generation chip of Liancore in LTE and will be directly oriented to commercial use. "From our own product development plan, the customer terminal products based on this chip should reach commercial use in the second quarter of next year," Sun Yuwang said.

At present, whether it is a TD-LTE network that Japan Softbank has already commercialized or a domestic TD-LTE service experience in Hangzhou, Shenzhen, and Guangzhou, the main form of the terminal is a data card. Sun Yuwang believes that from now until next year, the main terminal form of TD-LTE dual-mode is also data terminals, such as data cards, MIFI, CPE and so on. Speaking of when there can be terminals that support voice, he said: “TD-LTE mobile terminals must solve the problem of voice, and to be basically usable, the premise is to have fairly good stability and power performance. Acceptable. At the same time, TD-SCDMA/TD-LTE/GSM multi-mode operation is stable and reliable, supporting voice and data, and I estimate that it must reach the second half of next year."

Data terminals and smartphones also have different requirements in process technology. "At present, Lianxin supports data terminal chip products using the 40-nanometer process, and in the future we will certainly have to do 28-nanometer chips." Sun Yuwang said, "At present, data-based terminals using 40-nanometer chips are fully supportive, but they must be smart. For mobile phones, 28 nanometers can make power consumption even lower and technically more secure."

Improve MODEM Integration In 3G and LTE solutions, Modem's integration will inevitably be higher, from TD-SCDMA/GSM dual-mode to TD-LTE/LTE FDD/TD-SCDMA/GSM 4-mode, which requires the integration of Modem The degree of great improvement. In terms of application processors, there is not much difference in integration with 3G.

"For Lianxin, Modem is our strength, and it has always been the focus of our work. We integrate PMU and RF in the Modem, and at the same time, the power consumption is low and the size is small." Sun Yuwang told reporters, "In the application processor In terms of integration, we are selective, step-by-step, and will not do this kind of integration rashly, because integration means to do horizontal integration, but also means to promote better matching with other chips." Now that some chip companies Wi-Fi, Bluetooth, GPS, etc. are integrated into the application processor, but their performance is far from that of professional companies. "There are many specialized companies in the industry chain. If everything is a big package and the overall solution, the competitiveness of the products will not necessarily be better, so we are more cautious about the integration of application processors. Sun Yuwang said.

According to Modem's technical architecture, CTO Liu Jitang stated that at present, the TD-LTE/LTE FDD/TD-HSPA/GGE multi-mode chip LC1761 still uses the core ZSP in the core, and a large number of wireless processing is through Liancore’s own hard core. achieve. "The next phase of LTE, LTE Advanced, requires more data processing, and the current architecture will be a bit difficult. We are now doing multi-mode, multi-standby and multi-band compatibility, and we will use the SDR (Software Defined Radio) interface to do it." Liu Jitang Says, “In this way, we have several options to choose from. First, if third-party vendors have more mature IP, we can cooperate; second, we can consider developing ourselves.” Liu Jitang told reporters that Lianxin is doing research in this area. However, there is still a certain gap between commercial difficulty and commercial use.

The frequency band is undecided is a great challenge. LTE has multiple frequency bands available. The frequency band of China's TD-LTE is also changing. This has brought great challenges to the product development of chips and terminal companies.

“China now allocates 2.6-GHz and 2.3-GHz frequency bands to TD-LTE. Now China Mobile requires TD-LTE to support the 1.9-GHz frequency band, but many chips previously set at 2.6-GHz and 2.3-GHz could not be changed. "Liu Jitang said," The chip is not intended to be implemented immediately by adding a frequency band. The development of the chip requires a period from December to 16 months. Now many times the demand will suddenly be raised, and two or three months later it will be the product. This is very large." Challenge."

The change of the terminal chip in different frequency bands is mainly the radio frequency part. "On the one hand, we do our own research from the technical point of view, and the compatible frequency bands are as compatible as possible. On the other hand, we also need related departments to do a good job of frequency planning so that companies can do a good job in product development," said Liu Jitang.