Abstract: In this information age, without the transmission and exchange of information, people have been unable to adapt to the modern fast-paced life and work. With the rapid development of wireless mobile communication, wireless mobile communication technology has been closely related to people's lives, and people's daily lives are inseparable from various wireless communication devices.
Paper Keywords: D2D communication information
Chapter 65438 +0 thread theory
The research background of 1. 1
In the development of wireless technology in just a few decades, from the first generation analog cellular mobile communication network (AMPS) to the second generation digital cellular mobile communication network (GSM) supporting low-rate data services, to the third generation digital mobile communication network (3G) supporting mobile multimedia communication services [1] [2], to the fourth generation mobile communication technology supporting multimedia services with higher data transmission rates, The development trend of wireless mobile communication technology is to develop higher frequency bands, effectively use spectrum resources and digitize, which will provide equipment manufacturers and commercial operators with greater market space, create a huge commercial service group and provide them with good market space. With the continuous evolution of various mobile communication systems, the demand for bandwidth is increasing, and the shortage of frequency band resources has become the same problem in the world communication industry [3]. How to make better use of spectrum resources and create new value is a research problem with practical significance. Due to the limited spectrum resources, how to further improve the utilization rate of spectrum resources has become the core topic of wireless communication technology. In order to solve the problem of increasingly scarce frequency band resources, researchers proposed D2D(Device-to-Device) communication technology in cellular networks. D2D communication technology refers to the direct data transmission between two short-distance user equipments under the control of the base station by multiplexing the cell spectrum resources. D2D communication can be directly upgraded from the existing cellular network without large-scale laying and transformation process. The combination of D2D system and cellular system can not only expand cellular capacity, improve spectrum utilization, effectively reduce base station load, reduce battery power consumption of mobile terminals and shorten time delay, but also support new small-scale point-to-point data services. Nowadays, D2D communication technology, together with large-scale MIMO (Multiple Input Multiple Output), relay technology, ultra-dense deployment, flexible duplex and other technologies, has been identified as the key technology of IMT-Advanced. D2D will be more and more used in 4G LTE-A system because of its flexible working mode and practicability.
1.2 research status and development trend at home and abroad
People pay more and more attention to D2D communication technology, and researchers have done a lot of research in related fields. The research on D2D at home and abroad mainly includes the following directions: application scenario research, theoretical framework research and anti-interference research. Literature [4] proposes to establish a database through a base station? User dynamic matching database? DynamicMapping Users (DMU) are used to track the multiplexing status of all cellular frequency bands in time, and D2D devices actively select cellular resources with low multiplexing interference level to avoid or reduce interference. The mechanism and algorithm fully consider QoS, quality of service (QoS) of cellular network and mutual interference between two users. Literature [5] selects a reasonable pair of cellular users and D2D users based on the spatial isolation of users in the cell, which reduces the interference between the two communication modes and improves the throughput of the cell. Literature [6] proposes a resource allocation scheme for grouped users. D2D users in a cell are divided into several D2D user groups according to their geographical location, and then different resource frequency bands are allocated to different D2D user groups according to different allocation methods, and then the allocated resources are allocated to users in D2D groups, and each user group uses different resource allocation algorithms. Reference [7] gives a user mode mapping scheme for D2D communication. In this scheme, the base station first determines the geographical location of communication users in the system, then determines the communication mode suitable for each user according to the location information, and finally allocates corresponding resources to them. This pattern mapping scheme greatly reduces the complexity of system decision at the cost of limited performance gain. Literature [8] proposes two precoding algorithms for multiplexing cellular downlink based on single-cell cellular multi-antenna scenario to eliminate the interference caused by spectrum multiplexing. One is to search all the precoding in the known codebook exhaustively, and adopt the best precoding, which has a large system overhead. The other is a distributed algorithm. If accurate channel feedback can be obtained, even compared with the optimal precoding pair obtained by exhaustive search, higher gain can be obtained.
Chapter 2 D2D communication technology
2. 1 D2D concept
D2D (Device to Device) communication is a short-distance direct communication technology, which allows users to communicate directly by multiplexing cell resources under the control of the base station. This communication mode is beneficial to direct communication between local users in short distance, which can effectively reduce interference between users, reduce transmission signal power and improve resource utilization efficiency, and is especially suitable for local data transmission services. D2D communication is a way to establish a direct link between two communication terminals, so that the two communication terminals can communicate without forwarding through the base station. As shown in Figure 2. 1, D2D communication is different from the traditional cellular communication mode. D2D communication does not need to forward data through the base station, but directly communicates between users, which saves data transmission time and communication overhead, and also saves network resources. D2D users also have something in common with cellular users. D2D users need to be controlled and managed by the base station of the cell. D2D communication obtains the required communication spectrum resources and transmission power under the control of the base station, and carries out data transmission under the assistance and monitoring of the base station. Between D2D users and cellular users, independent resources can be used respectively, or the same resources can be used. Reasonable allocation of used resources can improve the resource utilization rate of cellular network. If both sides of D2D communication transmit at low power, the network load can be reduced, the power consumption of the terminal can be reduced, and the service life of the battery can be prolonged. D2D communication is a short-distance communication with high data rate and good communication quality, which can improve the capacity and spectrum utilization of cellular network. Moreover, with the increase of hotspot coverage of mobile network, the continuous improvement of data rate and the continuous popularization of Internet services, D2D communication will be used more and more.
2.2 Key Technologies of D2D Communication
The research and development direction of mobile communication is closely related to Internet applications, which means that more and more attention will be focused on data services, which will also be the focus of competition among operators in the future. Judging from the development trend of mobile communication, the mobile communication network is now in the stage of gradually changing from voice-based to high-speed data-based. In addition, the rapid development of mobile multimedia services also poses new problems to the bandwidth of mobile communication systems. D2D communication is also an application mode based on data services, which also requires mobile communication system to provide sufficient bandwidth support. At present, D2D technology has become one of the important research topics in wireless communication technology industry. How to realize it on the existing communication network infrastructure and solve its key technical problems has attracted more and more attention from academia and industry. The key technologies of D2D mainly include device discovery, power control, resource management and channel measurement [14]. When D2D communication is introduced into cellular communication, D2D users can reuse uplink resources or downlink resources of cellular users. After the introduction of D2D communication, it is very important to ensure that there is no interference to the original cellular users or that the generated interference can ensure normal cellular communication. Generally, interference is mainly solved by power control and resource allocation, although the characteristics of D2D interference have not been fully recognized. Power control only controls the transmitting power of uplink transmission of mobile communication users and downlink transmission of base stations [15] to ensure normal communication. The introduction of D2D communication in cellular communication needs to further control the transmission power of D2D users to ensure that cellular users are not disturbed. When the signal-to-interference-noise ratio (SINR) of the D2D receiver is minimum, the higher the power of the D2D transmitter, the better, which can make the received power higher, and thus obtain higher capacity. However, the higher the transmission power, the greater the interference to cellular users, and the system capacity will also be affected. Therefore, the purpose of power control is to find a balance between maximizing power and limiting the interference it produces.
Chapter III Research on Anti-jamming of D2D Communication with Frequency Multiplexing ... 5438+06
3. 1 system model. 16
3.2 D2D communication frequency reuse in core area 17
3.3 Frequency Reuse 2 1
3.4 Performance Analysis ... 25
Chapter IV D2D Communication Interference Control Based on Isolation Zone 28
4. 1 system model ...
4.2 Isolation area ... 30
4.3 Interference Analysis ... 30
4.4 Spectrum Efficiency 324.5 Performance Analysis 33
Chapter 5: D2D communication interference control based on alliance game. ...
The increasing demand for local services and increasing spectrum congestion have led to research activities aimed at improving spectrum efficiency in cellular networks. As a basic cellular network that can reuse cellular resources, D2D communication can improve spectrum utilization and enhance cell throughput. A key problem in D2D communication is interference management caused by resource sharing between D2D communication and traditional cellular communication, which will greatly affect network throughput and communication reliability. This chapter discusses the problem of resource sharing, and optimizes the system performance of D2D communication in cellular network from the perspective of distribution and cooperation prospect. In particular, a utility transferable alliance game [46 47] is formulated, in which each user cooperates with other users to form a stronger user group to obtain better spectrum resources and maximize their own utility. In addition, under the newly defined alliance maximum order, based on the alliance formation algorithm, a distributed fusion and splitting scheme is designed to effectively deal with the resource allocation problem. As shown in fig. 5. 1, consider the downlink transmission scheme in a cellular network, in which there are two communication modes, namely, the traditional cellular communication mode between BS and UE and the direct D2D communication mode, in which the traditional cellular communication is based on D2D communication. Emphasis is placed on the intra-cell interference caused by resource sharing between D2D and traditional cellular communication. Suppose there are m traditional cellular users and n D2D pairs in the studied network. Am，m= 1，2，？ .. m, representing traditional cellular users, Dn, t and Dn, r, n= 1, 2,? .. n represent potential D2D pairs, which are close enough to meet the constraint of direct D2D communication distance. Dn, t represents the sender of D2D pair, and Dn, r represents the receiver of D2D pair. Orthogonal frequency division multiplexing (OFDM) technology is used to support traditional cellular communication and D2D communication. R={RB 1，RB2？ RBk} stands for a total of * * * k modules for data transmission. Each module consists of a certain number of subcarriers. In the physical layer standard of LTE, each module consists of 12 subcarriers. Set { 1，2？ M}，{ 1，2？ . N} and the traditional set of cellular users, the set of D2D pairs is represented by M, N, A and D. ..
abstract
With the development of wireless communication industry, people expect to exchange information anytime, anywhere, timely and reliably, without the limitation of time and space, and improve work efficiency and economic benefits. Various wireless communication technologies that meet people's needs have made great progress. According to statistical research, at present, a large number of communications are transmitted in a short distance, so more work needs to be put into short-distance communication transmission, among which D2D technology is a new technology that users can directly transmit data by multiplexing cellular network resources in a short distance [50 5 1]. D2D communication not only improves the data transmission rate, but also reduces the power consumption and prolongs the service life of the battery. At the same time, it can also provide network coverage in marginal areas or hot spots, thus increasing the network capacity. This paper studies several key problems of D2D technology, including D2D equipment search technology, multi-hop D2D communication and anti-interference problems with D2D communication. Aiming at the key problem of interference, this paper makes in-depth discussion and research, and puts forward a specific anti-interference research scheme, which has certain reference value. Firstly, this paper introduces the research background of D2D, the concept of D2D and the research status at home and abroad in detail. For the increasingly scarce spectrum resources, D2D multiplexing technology in LTE cellular mobile communication system has been widely concerned. The interference control between two kinds of communication in cellular network has become a key problem in D2D application, and it is also the focus of this paper. Then, aiming at the anti-interference problem of D2D communication, three interference suppression and control schemes are proposed. One is interference control based on partial frequency reuse. According to the user's location, the cell is divided into core area and edge area, and the partial frequency reuse interference control scheme of D2D communication in core area and edge area is proposed respectively, and the feasibility of the scheme is proved by performance analysis. The other is D2D interference control based on isolated area, which solves the interference problem of D2D communication to original cellular communication and cellular communication to D2D communication through interference analysis and spectrum efficiency respectively. The last one is interference control based on alliance formation game, which shows that alliance formation game mainly controls interference based on integration of alliance formation and resource allocation of division of labor. Finally, the algorithm of alliance formation game is introduced.
References (omitted)
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