Mobile Terminal processor composition and baseband chip overview

(a) mobile terminal development

A mobile phone to achieve the most basic function-call to send text messages, this mobile phone will include the following parts: RF section, baseband section, power management, peripherals, software and so on. Look back at the history of mobile phones:

1, Function mobile phone (Feature phone): Only with baseband chip, can only be used to call, send text messages.

2, Multimedia Mobile: Use baseband chip + coprocessor acceleration unit. On the basis of the function machine, added multimedia functions (such as video, music). MTK is in the era of multimedia mobile phone rise, of course, thanks to the vast number of "cottage machine." In addition to the CPU, the MTK baseband chip also integrates many peripheral controllers. The functionality of the Feature phone is largely dependent on the peripheral features supported by the baseband chip.

3, Smart Phone: Using the application processor ap+ baseband processor Cp,ap can be seen as a traditional computer, CP can be seen as a wireless modem. The interface technology between AP and CP is SPI, UART, USB, SDIO, sharememory and so on. The communication between AP and CP can be done by traditional at command, Mbim, etc., and the functions such as call, Short message, mobile Internet are completed.

The difference between functional phones and smartphones is that the function machine is equivalent to a wireless communication terminal with increasing application function, no operating system, and the smart computer is equivalent to the PDA which increases the wireless communication function, and its software system is similar to the combination of PC software system-operating system + application software. The two most extensive operating systems for smartphones are Android and iOS systems.

There will also be a GPU dedicated to image processing in the smart machine, and the GPU will become more and more powerful, so we can watch HD movies and play high-quality games on the smart machine.

The high-pass baseband chip has the highest performance in the industry, the GPU is the leading edge of the NVIDIA, TI's AP is unique. The development of the future mobile chip is baseband, RF, AP even GPU integrated into a chip--SOC technology, so as to make the lowest power consumption, the smallest area of the chip. This paper briefly describes the function and composition of baseband chip.

(b) What is baseband chip

Mobile terminal support which network format is determined by the baseband chip mode, and what frequency band is determined by the antenna and RF module, baseband chip to complete the mobile terminal access function, the baseband processor is a highly complex system chip (SoC), which not only supports several communication standards (including GSM, CDMA 1x, CDMA2000, WCDMA, HSPA, LTE, etc.), as well as multimedia functions and interfaces for multimedia displays, image sensors and audio devices, the power management circuitry required for these compilation circuits is increasingly integrated in order to further simplify the design.

The RF and baseband sections are the core of the baseband chip. The current mainstream is to integrate the RF transceiver (small signal part) into the cell phone baseband, the future RF front-end may also be integrated into the mobile phone baseband, and with the integration of analog baseband and digital baseband more and more inevitable trend, the RF may eventually be fully integrated into the mobile phone baseband chip. The radio frequency section is generally the part of sending and receiving information, and the baseband section is generally the part of data processing. The baseband chip is used to synthesize the incoming baseband signal, or to decode the baseband signal received. The basic frequency is the most important part of the handset, is also the most technical content, only a few manufacturers in the world have this technology, including Texas Instruments, Ericsson Mobile platform, Qualcomm, MediaTek, NXP, Freescale, Infineon (now Intel Mobile Communications Division), Bo Tong, Spreadtrum.

Now, with the development of real-time digital signal processing technology, ARM microprocessor, DSP and FPGA architecture become the main way to realize mobile terminal chip. The ARM Master module realizes the communication between the physical layer and the protocol stack, receives the high-level instruction, and performs the corresponding task. DSP completes the physical layer baseband signal processing, including channel equalization, channel codec and telephone speech coding and decoding, there may be multiple DSP in Multimode baseband. When some algorithms in DSP are very stable, FPGA can be used to realize these algorithms and reduce the processing burden of DSP.

(iii) Characteristics of modern baseband chips

Baseband chip structure is still based on the MCU+DSP dual-processor core structure, but MCU and DSP processing power has been enhanced, lower power consumption, more and more high performance.

1, baseband chip integration has been improving, such as the RF RF and digital baseband integration, integrated GPS, WiFi module, integration of more application interface (such as camera, USB and other application interfaces).

2, memory organization, in order to enhance performance, reduce power consumption, reduce system costs. Both MCU and DSP have a separate cache (s), embedded in the large-capacity static random read memory (SRAM) and even large-capacity flash memory (Flash RAM). Extended memory generally supports synchronous dynamic random memory (SDRAM) and NAND flash RAM.

3, multi-mode mobile terminal baseband chip is inevitable, that is, eventually on a baseband chip to support all mobile network and wireless network format, including 2G, 3G, 4G and WiFi, etc., multi-mode mobile terminal can achieve a global range of mobile networks and wireless network between the seamless roaming. such as 3G baseband chip most support GSM/GPRS and WCDMA two modes, Qualcomm Company launched has CDMA2000, WCDMA, gprs/gsm multimode baseband chip. Qualcomm MDM9625 is the world's only one by one single-chip baseband with seven different RF modes integrated, including CDMA2000 (1xadv/ev-do rev. A/b), Gsm/gprs/edge, UMTS (WCDMA/TD-SCDMA), LTE ( LTE-FDD/LTE-TDD), mobile devices based on it can be used in any region of the world without any changes.

(iv) The current situation of baseband market

Baseband chip technology threshold high, long research and development cycle, capital investment (from the beginning of development to a stream of millions of dollars to move the unit), competition, so if the "station wrong team" or the finished product is easy to fall into the step of losing the loop. Many manufacturers have abandoned the baseband business, Freescale, Texas Instruments, Bo Tong, Nvidia has given up the baseband market, Ericsson from the aloof to now re-squeeze into the camp. Domestic Spreadtrum momentum, access to the national team after the financial support will be significantly increased into the market has been squeezed into the top three (Qualcomm, MediaTek, Spreadtrum, Intel, Qualcomm occupies the majority of the market 66%, MediaTek 15%, Spreadtrum 5%), Huawei HiSilicon self-sufficiency can not be ignored.

Note: What is multi-mode multi-frequency?

Baseband chip multimode refers to the support of a variety of mobile communication modes, the operator's communication mode includes mobile 4g-td-lte, telecom/Unicom 4g-lte FDD, Mobile 3G-TD-SCDMA, Unicom 3G-WCDMA, Mobile/Unicom 2g-gsm, telecommunications 3g-cdma2000, Telecom 2G-CDMA 1x, EVDO, and 3G Evolution HSPA technology.

Multi-frequency refers to the operating frequency under each network environment. Frequency means that each network format, each country is divided into several different frequency bands, so that different operators of mobile phones running in different frequency bands, do not interfere with each other. Popular point, like the radio, tune different frequencies are different stations, mobile phone network is also running on different bands. Some domestic operating bands are listed:

2G Network

gsm:850/900/1800/1900

3G Network (WCDMA/TD)

Wcdma:2100mhz/1900mhz/850mhz (China Unicom 3G)

Td-scdma:1880-1920mhz/2010-2025mhz (China Mobile 3G)

4G Network

Tdd-lte:1900mhz/2300mhz/2600mhz (China Mobile 4G)

Fdd-lte:1800mhz/2600mhz (4G of China Unicom and Telecom in the future)

On the market X-mode X-frequency mobile phone actually has more combinations, such as dual-mode, China is more likely to be three-mode eight-frequency, five-mode ten-frequency, five-mode 13-frequency of the three, China Mobile is the first five-mode 13-frequency, simply to support five communication mode and 13 corresponding band mobile devices.

Five-mode terminal can support Td-lte, LTE FDD, TD-SCDMA, WCDMA, GSM Five kinds of communication mode, support Td-lte BAND38/39/40,TD-SCDMA BAND34/39,WCDMA Band1/2/5,lte FDD BAND7/3,GSM Band2/3/8 and other 10 bands, some terminals can also support Td-lte band41,lte FDD band1/17,gsm Band5 and other frequency bands, to achieve terminal global roaming. Support five-mode 13-band mobile phone, that is, can support China Mobile and Chinese unicom 2G, 3G, 4G, that is, dual 4g! Such a mobile phone as long as the mobile card, is to support the mobile 2G, 3G, 4G network, if the plug-in card, on the support of China Unicom 2G, 3G, 4G network. The future of China Telecom's 4G mobile phone listing, will also have support for CDMA 1x/cdma2000 multimode 4G mobile phones, three netcom will eat more and more mobile phones.