Abstract：Under the background of 5G technology, this paper studies the direction control field of intelligent vehicle automatic driving. Most of the existing intelligent vehicle recognition algorithms rely on the error of center line to control the intelligent vehicle, and it is difficult to deal with the track elements′ center line which is not available. In view of this situation, this paper analyzes the robustness of the intelligent vehicle servo system, and explains the influence of the intelligent vehicle algorithm and mechanical characteristics on the robustness of the servo system. On this basis, a specific fuzzy direction control strategy is proposed, and the superiority of the strategy is verified by experiments. The analysis, solution strategy and experiment of intelligent vehicle system are beneficial to improve the intelligent vehicle system.
Abstract：This paper presents a non-orthogonal multiple access(NOMA) relay method which is based on mmWave wireless heterogeneous system and can support Internet of things(IoT) applications. The scheme takes advantage of the deployment specialty of low power relays，together with energy harvesting capabilities of IoT devices，so that it can infer the performance of UEs with relay collaboration. With the help of a relay or IoT device, the downstream NOMA transmission consists of two phases.(1)The base station(BS) transmits the composite signal to the user equipment(UE) and the selected relay device simultaneously by applying the NOMA. (2)The BS sends another signal to the UE 1 while the relay device transmits the signal to the UE 2. The simulation results show that the method designed in this paper is feasible and effective.
Abstract：In order to ensure the reliability, stability and high transmission rate of fifth-generation mobile communication technology(5G), this paper proposes a hybrid check matrix construction algorithm based on iterative coding algorithm with linear coding complexity. Firstly, this paper improves the traditional iterative coding algorithm and makes it suitable for non-binary low density parity check(NB-LDPC) codes. Then it adopts backward iterative method to change the coding scheme and the structure of the check matrix so that the progressive edge growth(PEG) algorithm has a lower triangular structure and uses it as the base matrix. Finally, a QC-LDPC algorithm with a lower triangular structure is used to generate a cyclic shift matrix and a finite field coefficient matrix. At the same time, the effect of the short loop is eliminated, and an optimal check matrix is selected from the algorithm. Simulation results show that the non-binary LDPC code constructed by the hybrid construction algorithm not only has linear coding and storage complexity, but also has strong error correction capability.
Abstract：In a 5G millimeter wave system, beam misalignment between a gNB and an UE may occur due to sudden fluctuations in the channel, user rotation, and so on. The beam failure recovery mechanism can help the gNB or the UE change its current failed beam to alternative(feasible) beam(s) based on beam measurement, thereby avoiding the frequent radio link failure caused by beam misalignment. This paper systematically expounds the design and implementation of beam failure recovery in 5G, including beam failure detection, candidate beam identification, beam recovery request transmission and gNB response，to provide essential reference for further research on beam failure recovery.
Abstract：Based on the parameters and characteristics of the fifth generation mobile communication(5G)system and the radio altimeter, this paper uses the antenna model and propagation model provided by the International Telecommunication Union(ITU) related proposals. Through Monte Carlo simulation, the coexistence of the 4 400～4 500 MHz band 5G system and the 4 200～4 400 MHz band radio navigation service(radio altimeter) is carried out. The results show that the 5G system does not cause harmful interference to the radio navigation service(radio altimeter) in the relevant frequency band.
Abstract：On June 14，2018，the 3GPP plenary meeting(TSG#80) approved the freeze of the independent networking function of the fifth generation mobile communication technology standard(5G NR). Coupled with the NR standard which was completed in December 2017, 5G has completed the first phase of full function standardization, and has entered a new stage of industrial sprint. The SA function freeze not only enables the 5G NR to have the ability to deploy independently, but also brings a new end to end new architecture, enabling the intelligent development of enterprise customers and vertical industries, bringing new business models for operators and industrial partners, and opening a new era of full connection. This paper firstly introduces 5G network key technologies, such as large-scale antenna, service-oriented architecture, edge calculation and network slicing, and analyzes the process and development status of 5G commercial application on the basis of elaborating the future business model applied in the three scenarios.
Abstract：For the guarantee of the development and testing of the fifth generation mobile communication(5G) technology in our country, and the protection of the normal work of the 3.5 GHz band fixed satellite service(FSS), the latest 5G system parameters and the simulation method provided by International Telecommunication Union(ITU) proposals are used to carry out the research of the coexistence of 3.5 GHz band 5G system base station with the FSS system in this paper. The results show that the 5G system base stations(BSs) has a large co-channel interference to FSS earth station at 3.5 GHz band, which makes it difficult to realize the coexistence of two systems at the same frequency, and the coexistence of two systems can be realized by some measures when the adjacent frequency is deployed.
Abstract：In the downlink of massive MIMO system, the sum-rate of the Minimun Mean Square Error(MMSE) and Singular-Value Decomposition(SVD) beamforming is better than that of the Maximum Ratio Transmission(MRT) and the Zero-Forcing beamforming (ZFBF), but the cost is the computational complexity of MMSE and SVD is much larger than ZFBF and MRT. At the same time, the computational complexity of ZFBF is much larger than MRT, however, when using ZFBF to transmit user signals, it can completely eliminate the inter-beam interference between users, and the sum-rate is better than the MRT algorithm, close to MMSE and SVD. This paper proposes a low complexity beamforming algorithm based on partial inter-beam interference cancellation for massive MIMO. The simulation results show that compared with ZFBF, MMSE and SVB, the low complexity BF algorithm proposed in this paper has a small decrease of the sum-rate, but it significantly reduces the computational complexity. The proposed scheme can achieve about 90% capacity of ZFBF while requiring 12%~19% computational complexity of ZFBF.
Abstract：Aiming at the problem of pilot pollution in massive multi-input multiple-output(MIMO) systems, this paper proposes a location-based pilot assignment strategy under the influence of Rician fading. The proposed scheme divides the user into two categories: the center user and the edge user by using the distance of the user arriving at the base station in each cell. Specifically, in order to improve the uplink achievable sum rates, the center user are operated with the random pilot allocation,and the dege user performs the pilot assignment base the principle of minimizing the line-of-sight(LOS) interference between the edge user in the target cell and the edge user in the interfering cell. The simulation results show that the proposed location-based pilot allocation scheme can effectively improve the performance of large-scale MIMO systems.
Abstract：In this paper, the feasibility of using Massive MIMO technology to transmit NB-IoT information is validated. First of all, this paper summarizes the current situation of NB-IoT, the difference with LTE and the problems encountered in the current development process. Secondly, the signal transmission process and system structure of Massive MIMO technology are explained. Finally, the experiments demonstrate that Massive MIMO technology can be used for NB-IoT by simulation to achieve the goal of extending battery life, increasing coverage, and increasing support for nodes.
Abstract：The successful application of 4G cultivates a flourishing mobile internet and enables us a convenient daily life. Our daily behaviors changed by mobile internet also cultivate new service and application for future. Besides serving the human, the mobile network is also expected to be applied to more and more elements of the society and enable the transformation and upgrade of different industries. To meet these requirements, 5G will provide extremely high spectrum efficiency, extremely low latency, extremely high density of the connections, and extremely low power consumption, and enable the vision of “information a finger away, everything in touch”. This paper gives the overview of the use cases and performance requirements of 5G system, and introduces the key technologies for the radio air interface and the innovative network architecture.