International Industrial Informatics and Computer Engineering Conference (IIICEC 2015) The research of key technologies in the fifth-generation mobile communication system Su Lina1, a, Chen Wen2,b, Chen Ping3,c, Lu Yanqian4,d 1 North China Electric Power University, No.689, Huadian Road, North District, Baoding, 071000 China a cfsulina123@163.com, b120164299@qq.com, c272952068@qq.com, d2423923669@qq.com Keywords: 5G; wireless communication; mobile communication technology. Abstract. In the paper, design and realization of a communication mechanism based on the fifth generation communication technology are mainly introduced. Combined with the latest trends in mobile communications development at home and abroad, this paper discussed the basic needs of 5G mobile communication development, technical characteristics and possible development paths. Furthermore, the paper focuses on the development prospects of three 5G mobile communications key technologies, including massive MIMO technology, D2D communication and filter bank based multicarrier technology. Based on the key technology above, we integrate advantages of many technologies, design and realize the system according to features of existing technology. In addition, the test result is good. Introduction Having been experienced from the development of first generation of mobile communication systems (1G) to the fourth generation mobile communication systems (4G), each generation of mobile communication system has its typical operational capacity and iconic technology. For example: Analog cellular technology of 1G system; time division multiple access (TDMA) and frequency division multiple access (FDMA) which based on digital cellular technology of 2G system; Code division multiple access (CDMA) which main characteristic is to support data and multimedia services of 3G system; Orthogonal frequency division multiplexing (OFDM) and multiple-input multiple-output (MIMO) technology of 4G system. In recent years, with the increasing demand for information and communication, the role of information and communication in people s lives is more and more important. Mobile with its wide application and convenience access will no longer be confined to interpersonal communication. Instead, there may exist the communication between people and objects, even among objects. There is explosive growth of people s needs in all aspects of communications. Therefore, there would be new challenges in frequency, technology and operation in 5G technology. Various new application scenarios, new type of business, new terminal equipment have made the development of 5G markets full of unknowns, so we need to make clear about the service and key technical indicators of 5G communication systems in order to guide the direction of 5G technics. So we need to design the communication mechanism to verify the features of fifth-generation mobile communication. Requirement of users Since 2000, the terminal business has transformed from traditional voice services to broadband data services, which result in diversified development of terminal side. In the future there will be various terminals such as watches, glasses and formed personalized multimedia information platform around individuals, industry and market. The popularity of intelligent terminal has made the combination of terminal and the Internet, thus bring in new business experience and interaction ability, stimulate users desire of mobile internet and drive the surge of data traffic. According to statistics, 70% of the smart end users time is spent on games, social networking and other activities. With the development of the terminal in the future, it will generate more data traffic. In 2020, the 2015. The authors - Published by Atlantis Press 483
service of intelligent terminal which approaches 1G Byte will no longer be a dream. UMTS Forum prediction data was shown in Figure 1. Communication mechanism design Fig.1 Data from UMTS Forum The properties of Manie depend greatly on the assumptions inherent in our methodology; in this section, we outline those assumptions. We consider an application consisting of n active networks. We believe that each component of Manie emulates the analysis of flip-flop gates, independent of all other components. This is a confirmed property of our application. We assume that each component of our methodology explores event-driven symmetries, independent of all other components. Although information theorists generally assume the exact opposite, Manie depends on this property for correct behavior. We executed some time trace verifying that our design is unfounded. We use our previously simulated results as a basis for all of these assumptions. Although security experts generally estimate the exact opposite, Manie depends on this property for correct behavior. Reality aside, we would like to investigate a framework for how our framework might behave in theory. We assume that each component of Manie is NP-complete, independent of all other components. We hypothesize that the development of the Ethernet can analyze the refinement of digital-to-analog converters without needing to harness efficient modalities. Figure 2 shows detailed flowchart of communication mechanism, wherein both parties in communication should transfer data through some modules each time, such as safety testing module Data management module Data analysis module and information display module. Massie MIMO mode D2D communication design mode Filter Bank Based Multicarrier mode Manie Client Send request Receive Data Data Analysis Data process Log in Transmission data Safety testing module Data management module Data analysis module Information display module Transmission data Manie Server Analysis request Data response Receiving results Fig.2 Transmission mechanism process Study of major technologies in 5G system Massie MIMO mode. As an effective means to improve the system spectral efficiency and transmission reliability, Multi-antenna technology has been applied to a variety of wireless communication systems, the number of which is much greater than the number of each signaling resource device. Furthermore, the use of SDMA (space division multiple address) can serve many users simultaneously. These advantages have made large-scale MIMO system become a major potential 5G key technologies. Although there is a huge potential in large-scale MIMO, it still faces some challenges. Channel estimation is the key and the main source of limitations. Because of the limitation of related interval and necessity of obtaining conditions to use the channel, there are a 484
limited number of orthogonal pilot sequences assigned to the devices. Furthermore, multiplexing the pilot sequence will cause pilot pollution and coherent interference and this phenomenon can be aggravated with the increase of the number of antennas. From an implementation point of view, massive MIMO can be achieved through each low-cost, low-power antenna semi-autonomous function modules, but there still needs considerable effort to prove the cost-effectiveness of the solution. D2D communication mode. Currently, the popularity of social network applications and local advertisement has made people s demand for short distance data communication increased significantly. However, there are many problems in coverage, capacity and power consumption (especially in close local communication services). Also, the lack of sufficient flexibility has made it difficult to fully meet the different unique business requirement in real-time and reliability. Therefore, the study of the D2D in 5G communication is necessary. D2D communication is a short-distance communication method, which can transfer the data between the terminals directly. D2D communication s main characteristic is that it can save resources, reduce interference, improve transport efficiency and reduce transport costs. Currently, there are two kinds of effective interference coordination mechanism: one is to control network users interference to D2D manner through tracking method, the other is to control D2D s interference to network users via tolerate interference broadcasts way. Filter Bank Based Multicarrier mode. Because of the advantage in spectral efficiency, against multipath fading, low implementation complexity and other aspects, OFDM technology is widely used in various types of wireless communication systems such as WiMaX, LTE and downlink road in LTE-A system. But there are many shortcomings in OFDM technology such as a waste of radio resources result from the insertion of cyclic prefix to combat multipath fading, a necessity of high PAPR because of the high sensitivity to carrier frequency offset, a limited flexibility of spectrum use because of the need to maintain the same bandwidth as well as maintain orthogonal of the sub-carriers, etc. In order to solve these problems, other multi-carrier implementations have attracted the attention of researchers. As the most important selection for multicarrier system in 5G communication, FBMC has attracted more and more people to do research about it. Since the performance of multi-carrier depends on the design of prototype filter and modulation filter, which is not conducive to flexible hardware implementation because of the specific requirement which requires the length of the prototype filter must be far greater than the number of sub-channels, developing rapid algorithm which meet the requirement of 5G filter group is an important issue in FBMC technology. Test result If the communication behavior of the 5th generation communication mechanism is not restricted, message is completely forwarded asynchronously, though most messages can reach objective after being forwarded for certain times, it can not be ensured that all messages can be delivered within limited number of steps. Especially when the communication nodes are moved frequently, it is prone to produce message chasing, which is not in line with basic requirements for reliable communication; even message chasing is not available, message will be forwarded more frequently, thereby extending the message transfer process, and lowing performance of the whole system. Possibility statistics of message forwarding frequency before delivery is analyzed as follows: possibility density curves are stimulated under two conditions of adopting and not adopting the above technology for speed limitation aiming at message with more forwarding frequencies. Obviously, under such system environment, message always can be delivered after being delivered more reasonably within limited frequency through speed limitation by the above technology. In addition average delivery time of message also can be gently reduced. Though the average delivery time is reduced by detaining related time, comprehensive performance of the whole system still can be improved if the parameter is deployed reasonably as shown in table 1. 485
Table 1 Forwarding Frequency Possibility Data Table under Preconditions of Adopting and Not Adopting Speed Limitation Forwarding time Error rate Node rate 0 12.21 14.5 0.5 10.4 13.3 1 8.4 12.8 1.5 6.2 10.3 2 4.1 9.5 2.5 3.2 8.4 3 2.1 7.8 We conducted a comprehensive test on 5G mobile communication technology applied in the system. Substitution rate and data size relation in the communication process as well as relation between transfer time and data size are mainly studied. Figure 3 shows that when the data size is increased, substitution rate is prominently reduced compared with communication technology in previous generations, and the data transfer time is also prominently shortened. It is proved that the system can well exert advantages of the 5 th generation mobile communication technology, and advantages of the 5 th generation communication technology are also verified. 40 250 35 30 200 Error Rate/% 25 20 15 10 5 3th generation 5th generation Time /s 150 100 50 5th generation 3th generation 0 1 3 5 7 9 11 13 15 17 19 size /M 0 1 3 5 7 9 11 13 15 17 19 size /M Conclusion Fig.3 test result According to the development law of mobile communications, 5G technology, which basic goal is to meet the requirement of rapid future development of mobile Internet business and bring new business experience to users, will be commercially available after 2020. 5G technology is still in its early stage and the next few years will be the critical period to determine its technology needs, key indicators and enabling technologies. Improvement of the capacity of 5G mobile communication system will be enhanced through spectral efficiency, changes of network structure and new spectrum resources development. With the development of future 5G research, the key technologies of 5G will gradually be clear and it will enter a substantive stage of standardization research in the coming years. The paper has advantages that technology realization features of the 5th communication technology are not analyzed in details. Rational specifications are not proposed for judging advantages and disadvantages of communication performance. Therefore, realization process of the 5 th mobile communication technology will be analyzed in detailed, and rational performance judgment basis will be proposed in the future. References [1]L.Yu: Chongqing University of Posts and Telecommunications Vol.4(2014),p.34-39. [2]X.H.You: Trends of 5G mobile communications development and key technologies (Science China Press, Beijing 2014). [3] T.L. Marzetta: Proceedings of the 40th Asilomar Conferenceon Signals, Systems, & Computers, Pacific Grove Vol.16(2006),p. 359 363. [4] C.X.Wang: IEEE Communications Magazine Vol.52( 2014),p. 122-130. 486
[5] B.Wang, L.Chen, X.H.Chen: IEEE 73rd Vehicular Technology Conference Vol.23( 2011),p.1-6. [6] J.Hoydis, T.S.Brink, M.Debbah :IEEE J Sel Area Commun Vol.31( 2013),p.160 171 487