Professor Zhang Ping, the director of WTI labs in BUPT, is one of the scholars who first participated in the research of 3G technologies in China. The lab led by him has an extensive research scope. So far it has completed several projects which are in the leading position both nationally and globally, including the projects sponsored by the Chinese Ministries, enterprises and the world-renowned foreign enterprises, etc. These projects cover a variety of fields, such as the narrowband CDMA, broadband CDMA and the TD-SCDMA , etc. Especially in the B3G field, their lab is one of the research institutes that started in the earliest stage and has the deepest insight in this field. Professor Zhang Ping has done in-depth research in TDD and FDD technology in the mobile communication field. TD-SCDMA forum interviewed professor Zhang Ping recently and asked him to express his viewpoints regarding the direction of future mobile communication.

Professor Zhang said, in the mobile communication field, TDD technologies was positioned as one of the frontier technologies in its initial stage by a lot of foreign countries and was regarded only as complementary to the FDD technology. However, after years of effort, now people has proven, at least theoretically that TDD is just like FDD technology, it is also a mobile communication technology which can be used in the high-speed moving environment for large area coverage and high-speed data download. The existence of dubious views of its future prospects comes from that the TDD technology got off to a late start and currently no commercial network can be used to verify its actual performance. This means that there is still a lot to do in the TDD field. More R&D vendors and research institutes should be introduced into this field. TDD is a large industry chain and has its great significance in the future development of mobile communications.

Zhang said, as everybody knows, the spectrum usage efficiency of TDD is higher than that of FDD, its signal processing is relatively simple and has its natural advantages in processing asymmetric services. It is also easier to find the suitable frequency band in its deployment. Zhang said, if TD-SCDMA can succeed, the third generation TDD technology will be a robust competitor to FDD technology. He believes that in the World Wireless Technology Conference scheduled in 2007, TDD frequency band will be a hot topic to be discussed; at least it will be juxtaposed with FDD frequency band. Zhang Ping said, our country has done a lot of work in the TDD field and has laid a solid foundation for its future development. We are now in a leading position. He went on to say that in the future, a competition situation will be shaped in FDD field and this should also be considered by our country. We should fully exploit our favorable conditions and avoid unfavorable ones and study carefully our advantages. These advantages mainly lies in the research of key technologies, the planning and commercial use of frequency resources and the application of services, etc. We should explore new channels in this field.

For the future development of mobile communication, especially the development of B3G, Zhang said what people cares more may be the difference of B3G and 3G. Let’s look back to the initial stage of 3G research, at that time the research was following the lead of GSM, at least the radio interface was designed by the combination of 64K. As a result, many factors were not taken into consideration. For example, the speed of multi-media service is not enough. So higher transmission speed and better quality services will be achieved in the enhanced 3G technology. Current research shows that the CDMA technology is not the most effective one in high speed data transmission, especially the paroxysmal data transmission. As a result, the high speed data is now being transmitted with the TDM mode. From the perspective of services, the network development is not only the development of radio interface, but also the development of the whole network and the business model. Of course, higher speed can be achieved by using the B3G technology. With the increase of the frequency, the cell area will be decreased, and a series of technical problems need to be tackled. Professor Zhang believed that the future of TDD technology is very promising. He said that the distance of communication will decrease with the frequency increase and more and more advantages of TDD technology will be revealed.

When talking about 4G, Zhang said that we should have a complete new mindset. He said that the objective of communications is not to setup a good and high-speed connection, but to provide services. What should be embodied in 4G is the human concern. Professor Zhang Ping indicated that the criteria in designing the 4G communication network should be ABE (Always best experience), which means to always provide the subscribers with best experiences. But how to make these idea realize? Professor Zhang explained that if people’s feeling is considered to be the best, then the network need to perceive their status, their position and their environment, and then it can customize this feeling for us. The services will distinguish automatically people’s emotion and demand, which is to say that the communication network will evolve towards the intelligent and emotional one, rather than a cold and unemotional machine. Zhang Ping introduced that WTI lab has done a lot of work in this field and it is fully possible to make the machine adept to our environment. He believes that the capacity of connectivity and transmission is not the absolute criteria for evaluating 4G. The layout of wireless terminals can also be diversified. Not all services can be accomplished by one terminal. All should serve and provide us with the best experience. 4G can only be developed if it can achieve all these. This will be a rather long process. 20 years have passed since the initiative of 3G research and 4G will have a longer way to go. It may be too early to talk about B3G or 4G at present.