What key technologies are needed for 5G networks?

- Jul 06, 2019-

4G network communication is in the ascendant, and 5G network communication has entered people's field of vision. Not long ago, China's Huawei company's Polar Code solution became the 5G control channel eMBB scene coding scheme.

The core patent is composed of several systems. Qualcomm has two core patents of soft switching and power control and 2,000 peripheral patents in the 3G network era. It has been levied by global communication companies such as Ericsson, Huawei, Nokia, and ZTE. The technical capital of Qualcomm Tax. Then, what changes have been made to 5G network communication and 4G network communication, and what fundamental innovations are needed to make 5G?


What is 5G network communication?


5G, as its name implies, is the fifth generation communication technology, and 3GPP defines five major scenarios of 5G:


Enhance Mobile Broadband (eMBB), according to the plan, can provide users with 1Gbps user experience rate and 10Gbps peak rate in densely populated areas, and achieve traffic density of tens of Tbps per square kilometer in the traffic hotspot area.


Massive Machine Type Communication (mMTC) not only connects medical instruments, household appliances and handheld communication terminals, but also targets sensing and data acquisition for smart cities, environmental monitoring, intelligent agriculture, forest fire prevention, etc. Application scenarios and support capabilities with over 100 billion network connections.


Ultra Reliable & Low Latency Communication (uRLLC), which is designed for intelligent unmanned driving, industrial automation, and other services requiring low latency and high reliability, providing users with millisecond-level end-to-end delay and nearly 100% service reliability. Guarantee.


It can be seen that compared with 4G network communication, 5G network communication can provide a wider coverage of signals, and the Internet is faster and has higher traffic density. At the same time, it will penetrate into the Internet of Things to realize smart city and environmental monitoring. The deep integration of intelligent agriculture, industrial automation, medical instruments, driverless, household appliances and handheld communication terminals, in other words, the Internet of Everything.


What are the key technologies for 5G network communication?


In the channel control eMBB scenario, Polar beat the US LDPC and France's main Turbo2.0. It is believed that Huawei has mastered the 5G core patent and used Huawei to crush Qualcomm and win the 5G network. To describe. But this description is more debatable.


The eMBB scene coding scheme that Qualcomm and Huawei compete for is not a core patent in this matter. The core patent is composed of several systems. Generally speaking, the physical layer is considered to be the core technology at the core. This includes coding. The coding can transmit signals on the one hand, and the coding technology can also increase the anti-interference ability. Turbo2 .0, Polar Code, LDPC is the coding scheme currently promoted by France, China and the United States.


The other one is multiple access. The multiple access technology refers to the problem of solving the problem of multiple users communicating with the base station at the same time. How to share resources? The first generation communication uses FDMA technology, and the second generation communication uses TDMA technology. The third generation of communication uses CDMA technology, the fourth generation of communication uses OFDMA technology, and the multiple access in the 5G network era is a key point of competition. The popular view is now NONA. However, Yang Xuezhi, the inventor of the "soft frequency reuse" foundation technology of 4G network, recently wrote "NOMA is just a misunderstanding", and believes that NONA may not be able to win the 5G era, there are still certain variables.


Another key technology is multi-antenna, which is a technology that increases capacity and theoretically increases the capacity by many times. To put it simply, by increasing the number of antennas and even tens or even hundreds of antennas on the basis of existing multi-antennas, dozens of independent spatial data streams can be supported, and the spectrum efficiency of the user system is greatly improved. Nowadays, the MIMO technology is relatively hot. The massive MIMO technology can not only reduce the transmission power without reducing the spectrum resources, reduce the intra-cell and inter-cell interference, but also improve the spectrum efficiency and power efficiency on the basis of 4G. An order of magnitude. In addition, RF modulation and demodulation technology and soft frequency multiplexing technology are also key technologies, and the latter is in the hands of Huawei.


Turbo2.0, Polar, LDPC are better or worse


The LDPC promoted by Qualcomm is proposed by Gallager, the international information field, about 50 years ago. After more than 50 years of development and improvement, the technology is very mature. Although some of the ideas have not been called advanced because of the earlier time proposed. However, after many improvements and expansions, it is still a very good technology. Turbo 2.0, which is mainly promoted by France, is an extension and development of Turbo. Turbo code is one of the codes used in the 4G era, and it is also very mature in technology.


The Polar code that China mainly promoted was first proposed by Professor Erdal Arikan of the University of Birken in Turkey in 2008. The advantage of the polar code is its strong error correction capability, and it is the only one known in the world that can be strictly proved to reach the channel. The channel coding method of capacity, which is of great significance for the specification management of high-bandwidth networks, has achieved the same or better performance as Turbo codes and LDPC codes in some application scenarios. But the disadvantage is also very star, that is, the birth time is too short, the technology is not mature enough.


In fact, the three codes are very good technologies. The reason why LDPC can capture the long code and short code channel of eMBB scene, Polar can obtain the control channel of short code in eMBB scene. The root of the problem lies in The game of big country's comprehensive national strength.