can be used for L3 autopilot to decrypt TI 77GHz millimeter wave radar single chip scheme

Recently, a Texas Instruments (TI) spokesman shared with the media its latest ADAS product AWR2944 millimeter wave radar chip, which is TI's second generation millimeter wave radar single chip with a working frequency band of 77GHz and is suitable for scenes such as adaptive cruise, automatic emergency braking and forward collision warning.

Vehicle Millimeter Wave Radar in Future

millimeter wave radar is generally 30GHz-300GHz, and the wavelength is between microwave and centimeter wave (1mm-10mm), which has the advantages of microwave radar and photoelectric radar. From the perspective of application frequency bands, there are two main types of mature commercial vehicle millimeter wave radars: 24GHz(MRR, short and medium range radar) and 77GHz(LRR, long range radar). Among them, the 24GHz MRR detection distance is within 70 meters, which is suitable for blind spot monitoring (BSD), lane change assistance, adaptive cruise (ACC), automatic emergency braking (AEB) and other scenarios; the detection distance of 77GHz LRR is several hundred meters, mainly Used in adaptive cruise, automatic emergency braking, forward collision warning (FCW) and other scenarios.

In essence, 24GHz products are not much different from 77GHz products, but the latter has small size, low power consumption, high bandwidth, good resolution, and long detection distance, and is considered to be the mainstream direction of future automotive millimeter wave radars. At present, domestic automotive millimeter wave radar products are mainly in the 24GHz band, and its supply chain has been relatively mature, with a market share of more than 50%.

, a reporter from "International Electronic Commerce" noted that on December 6, 2021, the Ministry of Industry and Information Technology issued the "Interim Provisions on the Radio Management of Automotive Radar", which clearly stated that "in order to promote the application of automotive intelligent technology and industrial development, the 76GHz-79GHz frequency band will be planned for automotive radar". The regulation also states that "applications for approval of radio transmission equipment models for 24.25 GHz-26.65GHz band automotive radars will no longer be accepted and approved" as of March 1, 2022 ". This means that 77GHz on-board millimeter wave radar can be expected in the future of China's automobile market!

According to the data of the third-party market research agency, the market size of China's vehicle millimeter wave radar will reach 3.6 billion RMB in 2020. It is expected that in the next few years, China's vehicle millimeter wave radar will grow rapidly at a 40% growth rate. However, China's millimeter wave radar domestic substitution space is large, the market share is mainly occupied by international manufacturers, the current domestic millimeter wave radar accounts for about 20%-30% market share. For international millimeter wave radar suppliers, China is a market with great potential.

TI provides a full set of ADAS solutions

As mentioned above, attracted by the excellent market prospect, international millimeter wave radar participants pay more attention to the Chinese market, and TI is one of them. Recently, TI launched the millimeter wave radar chip AWR2944 for the Chinese market, which is a new second generation millimeter wave radar single chip. According to Cai Zheng, general manager of Texas Instruments China Automotive Business Department, this is a 77GHz millimeter wave radar chip. The signal can be output from the chip during operation, and then returned to the processor through a high-speed signal link solution.

"2021 is regarded as the first year of China's automotive automation. Many automakers have introduced autonomous driving/assisted driving models. A hundred schools of thought are contending and a hundred flowers are blooming in the market." Cai Zheng explained that the development trend of ADAS is dominated by three major directions: first, relevant laws and regulations, including new car evaluation procedures (NCAP), UN regulation No. 79, etc.; The second is the automobile structure. A good structure can shorten the time for new cars to go on the market and save costs for car companies. The third is the application of emerging sensing technologies, including 60GHz/77GHz millimeter wave radar in driving fatigue detection system (DMS) and automatic auxiliary parking scene.

the following information to highlight the importance of autonomous driving and assisted driving:

• the 2018 Global Road Safety Status Report released by the World Health Organization shows that the number of deaths due to traffic accidents worldwide has reached 1.35 million each year;
• the Federal Highway Administration (FHWA) estimates that more than 50% of traffic casualties occurred at or near intersections;
• China's latest census data show that as of 2020, there are 91 cities with a population of more than 5 million, and China is also the country with the largest population of one million;
• UN Regulation No. 79 defines the new motor vehicle safety requirements and new vehicle evaluation procedures (NCAP) standards-automakers must improve their ADAS steering systems to support intelligent assistance and autonomous driving.

to this, Cai Zheng stressed: "TI has been working in the field of self-driving and assisted driving for more than ten years. Its products cover all fields of self-driving, which can help customers and Tier 1 manufacturers quickly design products that meet the requirements of laws and regulations and their own systems." It is understood that there are three types of products related to the ADAS system launched by TI: the first is the perception category, including millimeter wave radar products, which can digitize the information about the situation outside the car and the driver's condition inside the car, and transmit this information to the processor in the system. The second is the processing class. TI has accumulated more than 10 years of experience in automotive processors and has experienced iterations of products such as TDA2x and TDA4x. Thirdly, in the communication category, the improvement of perception capability increases the requirements for data throughput, while the information collected by the sensor end (camera, millimeter wave radar) is transmitted to the processor through a high-speed signal link, and TI can provide string/de-string products to meet the data throughput requirements of the autonomous driving system.

power supply systems for automotive cameras and radar applications, TI can also provide a complete set of power management solutions. AWR2944 have been updated in equipment safety and power management: in equipment safety, the AWR2944 has embedded functional safety module, built-in R5F, special memory, input and output interfaces and some code hardware. In power management, the single chip scheme based on AWR2944 integrates RF and RAM control, and the data exchange efficiency of RF and RAM is very high, so it has a good performance in the overall energy consumption ratio.

AWR2944 Single Chip Scheme

autonomous driving system can be divided into three parts: one is perception, using radar and sensor technology to sense the situation of the surrounding roads of the car; the other is decision-making, using the processor to analyze the data to provide control strategies for the autonomous driving decision-making mechanism; The third is control, which completes the control of the entire car body through the host, so as to achieve the purpose of avoiding risks. With the continuous improvement of the function of the autonomous driving system, it also puts forward higher requirements for perception accuracy. Cai Zheng revealed that this is also one of the reasons why TI's research and development AWR2944.

Regarding the performance and parameters of the AWR2944, Jiang Hong, Director of Embedded Product Systems and Applications of Texas Instruments China, gave a detailed introduction: "We launched the second-generation pre-chip AWR2243 in December 2020. After customer evaluation, testing, and adoption, the AWR2243 was highly praised. Now, we have launched the second-generation single-chip AWR2944, which meets the AEC-Q100 certification and ASIL-B-level standards. Compared with the previous generation of products, it has been upgraded in many aspects."

According to Jiang Hong's introduction, the size of the AWR2944 radar system has been reduced by 30%; the AWR2944 supports 4 transmitters and 4 receivers, and its resolution is improved compared to AWR2243; the AWR2944's comprehensive RF performance is 50% higher than the AWR2243; the AWR2944 has built-in hardware acceleration units such as DDMA and C- PHY, which can increase the radar detection range of 40%; the AWR2944 has also increased memory, upgraded the processor core, and can build more advanced algorithms, bring performance upgrades to customers' angular and forward radars.

now some car companies have used AWR2944 in the angular radar and forward radar of L2 and L2 + systems to adapt to the blind spot monitoring system (BSD) and automatic emergency braking system (AEB) applications. Since the AWR2944 supports 4 transmitters and 4 receivers, it can accurately detect forward targets when FOV (field of view angle) converges, so it can also be used as a forward radar. Of course, if the automobile system is upgraded to L3 and L4, the AWR2944 can also be used as millimeter wave sensors in conjunction with other radars. In addition, the AWR2944 can also meet the application in the cockpit. At present, TI's 60GHz millimeter wave radar products focus on intelligent cockpit scenes, which can realize driver sign detection and gesture recognition applications.

Due to the small size of 77GHz millimeter wave radar, its circuit board area is very small, which makes it difficult to submit the design of radar RF circuit and the yield of finished products is also low. As mentioned earlier, the size of the AWR2944 radar system is reduced by 30%, the resolution is increased by 33%, and the detection range is increased by 40%. How does TI solve the problem of RF line design and yield?

Jiang Hong replied that radio frequency lines and yield are actually considered in many aspects. Antenna design is a very professional field. It not only involves theoretical issues, but also involves line simulation testing, materials, technology, board making, etc. All of the above require very professional technical accumulation. It is gratifying that the entire industrial ecology is now making rapid progress in this regard.

back to TI itself, TI can help customers solve radio frequency circuit design problems. Because there are many self-calibration modules inside TI's chip, for example, the on-board radar has strict requirements on the working temperature, and the car may drive outdoors below -20 ℃ or above 60 ℃. In response to stringent operating temperature requirements, TI's IC has many on-chip/on-chip/open-loop self-calibration, and many links can be interlinked to ensure product stability, which can also improve the yield of end products.

TI Planning for Automotive and Millimeter Wave Radar

from ADAS to autopilot, L1-L5 requires regulations first, and the development of sensors also needs to comply with corresponding regulations. While self-driving cars put forward high requirements for perception, they also put forward the requirements of "all-weather work", "detection distance is longer" and "perception information dimension is more/more accurate" for sensors. In addition, there are also trends such as intelligence and sensor fusion in the automotive field.

Jiang Hong believes that the actual needs of customers also play a vital role in the development of sensors. "Vehicles with ADAS function will generally be equipped with 5R1V(5 millimeter wave radars, 1 vision sensor), and 8R(8 millimeter wave radars) may be equipped in the future, with even higher requirements. The blessing of many radars and sensors has also prompted OEMs to consider the issue of cost performance.

Cai Zheng said that TI's macro direction will not change. First of all, TI has a wide range of product lines in the automotive field. Up to now, there are nearly 8000 automotive products and hundreds of new products will be launched every year. This is something TI has always insisted on. Second, TI announced a capacity expansion plan in 2021, which will guarantee the supply of TI automotive chips. Again, as China's emerging markets are expanding rapidly, TI will keep in touch with the head Tier 1 manufacturer. "Building new architectures in areas such as central gateways and autonomous driving is the direction we are working with domestic car manufacturers. In addition, we are also seeing the need to upgrade in-car communications, which puts forward demanding requirements for the throughput capacity of communication rates and the effectiveness of transmission efficiency, and TI enhances its support for the relevant markets through the release of new products." Finally, the trend of intelligence brings new opportunities. For example, intelligent LED headlights not only have lighting functions, but also have human-computer interaction functions. TI is also discussing and planning relevant leading equipment and innovative applications with head customers.

Since 2021, the forward radar in the Chinese market has grown very fast. Many consulting firms predict that China will become the world's largest forward radar market by 2023. Many TI customers began to make 2 cascade and 4 cascade 4D imaging radars based on AWR2243 chips. This radar maintains the accuracy of millimeter wave for ranging and speed measurement, and also greatly improves the angular resolution.