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279results about How to "Solve the delay problem" patented technology

Hybrid spread spectrum communication system based on low density parity code (LDPC) encoding and method thereof

The invention discloses a hybrid spread spectrum communication system based on low density parity code (LDPC) encoding and a method thereof. The problems of leakage capture, high leakage capture probability, slow convergence of a phase-locked loop and low decoding performance of the existing synchronous capture method are mainly solved. The system comprises a transmitting part and a receiving part, wherein the transmitting part is used for carrying out pretreatment on original information; the pretreatment data are subjected to frequency hopping treatment and transmitted after being modulated and filtered by a base band; the receiving part is used for obtaining a synchronization point position and a frequency offset value in the received signal through synchronous capture, and intercepting useful data to carry out de-hopping according to the synchronization point position; the base band demodulates and filters; the filtering data are subjected to frequency offset compensation according to the frequency offset value; the data after frequency offset compensation are subjected to dispreading and frequency offset rectification; the frequency offset rectification data are decoded and the decoding result is output. The hybrid spread spectrum communication system has the advantages of being strong in burst error resisting ability, high in real-time synchronization capture speed, high in capture accuracy, high in convergence speed of the phase-locked loop, and good in decoding performance, and can be applied to reliable communication under the condition of very low powder spectral density.
Owner:XIDIAN UNIV

Fault detection method of nonlinear network control system based on event triggering mechanism

ActiveCN108667673AIncreased failure sensitivityTroubleshooting fault detection issuesElectric testing/monitoringData switching networksEvent triggerSystem failure
The invention provides a fault detection method of a nonlinear network control system based on an event triggering mechanism, and relates to the technical field of network system fault detection. Themethod comprises the following steps: firstly, establishing a T-S fuzzy model of the nonlinear network control system, setting an event triggering condition, establishing a fuzzy fault detection filter model, establishing a fault weighting system, and then establishing a fault detection system model; selecting an appropriate residual evaluation function and a detection threshold according to the fault detection system model, and detecting whether a fault of the nonlinear network control system occurs; and finally, further designing a parameter matrix and an event triggering matrix of a fault detection filter according to the stability of the fault detection system and sufficient conditions of existence of the fault detection filter. By adoption of the fault detection method of the nonlinear network control system based on the event triggering mechanism provided by the invention, the robustness to external disturbance and communication delay is greatly improved, and the limited networkresources and computing resources can be saved by the application of the event triggering mechanism.
Owner:NORTHEASTERN UNIV

Cellular user clustering communication method and system as well as eNodeB and terminal

The invention discloses a cellular user clustering communication method and system, an eNodeB and a terminal and relates to the field of mobile communication. The method comprises the following stepsthat the eNodeB establishes at least one cluster according to the position distribution relationship of a user terminal and determines a cluster head terminal and cluster member terminals, which belong to the cluster; the eNodeB allocates a cluster ID and cluster channel resources to the cluster head terminal; and the cluster head terminal receives a request for establishing a D2D connection between the cluster member terminals and allocates the cluster channel resources to the D2D connection in order to enable the cluster member terminals to communicate through the cluster channel resources.According to the method, the system, the eNodeB and the terminal, the user terminals in a cell are divided into a plurality of user clusters according to the positions, the resources are allocated according to the clusters, the cluster head provides intra-cluster information aggregation broadcast and realizes direct communication of the intra-cluster users, autonomous clustering and device-to-device communication can be achieved, the requirements of services for transmission characteristics, such as communication delay and reliability, are met, and the resource utilization efficiency is improved.
Owner:CHINA TELECOM CORP LTD

Webpage-based remote comprehensive diagnosis and treatment system

The invention discloses a webpage-based remote comprehensive diagnosis and treatment system, which comprises a server side and a client side. The server side is provided with a built-in WEB server, a high-definition video encoding module and a bidirectional voice communication subsystem. The built-in WEB server is used for acquiring various data, waits to be connected with users and realizes data transmission with the client side in a communication manner after being connected with the users successfully. The high-definition video encoding module completes acquisition and encoding of video data of the server side, wherein the encoding is completed by the aid of a hardware encoding chip. The bidirectional voice communication subsystem is mainly used for realizing communication between doctors and patients during the remote medical treatment process, realizing bidirectional voice cross-platform communication while solving the problems of noise and time delay in communication. The client side is a WEB-based high-definition video decoding client side. Compared with the conventional remote medical treatment system, the webpage-based remote comprehensive diagnosis and treatment system has the advantages of portability, easiness in use, high adaptability and communication quality and the like.
Owner:SHANGHAI JIAO TONG UNIV

Vehicle networking communication optimization algorithm based on edge computing and Actor-Critic algorithm

The invention relates to a method based on edge computing and an Actor-Critic algorithm. The specific steps are as follows: in the vehicle networking communication system, the user sequence is {1, 2,..., k,..., K}, and there are K users; the subchannel sequence is {1, 2,..., n,..., N} with N subchannels; fog access node sequence {1, 2,..., m,... M}, total M access nodes, computing power sequence of incoming nodes {1, 2,... Cm,..., cM}; task sequence {1, 2,... tk,..., tK} uploaded by user, total tK tasks; a non-orthogonal multiple access (NOMA) mode is adopted to connect the user to the vehiclenetworking communication system. The task uploaded by the user carries out edge calculation and returns the calculation result to the user; taking advantage of actor-Critic algorithm to optimize theresource allocation method and get the best resource allocation method. The invention combines the non-orthogonal multiple access, the edge calculation and the reinforcement learning, effectively solves the problem of huge access quantity existing in the vehicle networking, simultaneously reduces the time delay in the whole communication process, obtains the best resource distribution mode under different environments, and improves the energy utilization efficiency.
Owner:QINGDAO ACADEMY OF INTELLIGENT IND

Internet of Vehicles cross-domain authentication method based on side chain technology trust model

ActiveCN112153608AMeet the needs of efficient cross-domain identity authenticationGuaranteed unforgeableEncryption apparatus with shift registers/memoriesParticular environment based servicesThe InternetEngineering
The invention provides an Internet of Vehicles cross-domain authentication method based on a side chain technology trust model. The Internet of Vehicles cross-domain authentication method comprises the following steps: S10, an initialization and registration stage; S20, a cross-domain vehicle identity verification stage; S30, repeating a cross-domain authentication stage; and S40, in an identity logout stage, if the RSU receives a plurality of logout applications for the same vehicle ID, informing a CA center of the logout applications, the CA center binding the identity ID of the vehicle to be logged out with a logout identifier 'REVOKE' and signing and disclosing the logout identifier 'REVOKE' in a main chain layer, and if the intelligent contract retrieves that the vehicle identity ID is marked with 'REVOKE', indicating that the vehicle identity is logout and cannot access a network. According to the Internet of Vehicles cross-domain authentication method based on the side chain technology trust model, the block chain side chain technology is innovatively applied to cross-domain identity authentication research of the Internet of Vehicles, and unforgeability, tamper resistance and traceability of vehicle identities are guaranteed through the characteristics of block chain distributed data storage and the like; the problem of centralized single-point failure of a cross-domainauthentication mechanism of the traditional Internet of Vehicles is solved.
Owner:NANTONG UNIVERSITY +1

Beam optimization method based on user discovery stage in millimeter wave system

The invention discloses a beam optimization method based on a user discovery stage in a millimeter wave system, comprising: modeling a millimeter wave communication system by adopting a random geometric method, and determining a path loss of the millimeter wave communication system and a beamforming gain model to obtain a receiving signal of the millimeter wave communication system; establishing coverage and capacity expressions of the millimeter wave communication system, comparing and analyzing the coverage performance of the system without considering interference and noise; determining therelationship between the capacity of the millimeter wave communication system and the search delay with the beam width as the intermediate quantity, optimizing the beam width to obtain the optimal system performance; using the beamforming technique in the user discovery phase of the millimeter wave to obtain the optimal beam width, and scanning the entire beam space for user search. By optimizingthe scanning beam width of the user discovery phase of the millimeter wave system, the invention solves the problem of the balance between the search delay and the system capacity, and obtains the optimal system performance, thereby saving the cost.
Owner:XI AN JIAOTONG UNIV

Multi-replication routing method for selecting eruption range in vehicular vdhoc networks

ActiveCN103763193AImprove delivery rateStrong performance such as reliabilityData switching networksDirectivityNODAL
The invention discloses a multi-replication routing method for selecting an eruption range in vehicular vdhoc networks, and belongs to the technical field of the vehicular vdhoc networks. The multi-replication routing method for selecting the eruption range in the vehicular vdhoc networks comprises the steps that a method for limiting the multi-replication eruption range is adopted, message replications of different numbers are erupted in different ranges in different directions according to movement of a vehicle, and directivity of message transmission can be better; three node performance indexes are added, and neighbor nodes with best performance are selected to serve as forwarding nodes according to the node performance indexes through a fuzzy logic learning system; a cache scheduling strategy used for having control over jamming is adopted. According to the multi-replication routing method for selecting the eruption range in the vehicular vdhoc networks, the problem that network overheads are overlarge due to blind flooding of the message replication number in multi-replication routing is solved, and the problems that due to the fact that direct transmission is passively adopted, the delivery rate is low, and delay is large are solved; compared with a traditional method, timeliness, reliability and other performance are better, and the multi-replication routing method is more applicable to the vehicular vdhoc networks with high-dynamic topology.
Owner:CHONGQING UNIV OF POSTS & TELECOMM

Method for measuring delay of direct sequence spread spectrum binary phase shift keying modulator

The invention discloses a method for measuring delay of a direct sequence spread spectrum binary phase shift keying modulator. Data despreading and demodulation and delay dependence are taken as cores, the delay measurement of input/output signals with different frequencies and different waveforms of the direct sequence spread spectrum binary phase shift keying modulator is converted into the delay measurement of signals with the same frequency and the same waveform, and is implemented by a created system. Digital signals are divided into two paths by a baseband signal generator (1) through apower divider (2), one path of digital signals pass through a direct sequence spread spectrum binary phase shift keying modulator (3) to be tested and enter a high-speed data acquisition unit (4), and the other path of digital signals are directly output by the power divider (2) to the high-speed data acquisition unit (4). A demodulation module (5) and a dispreading module (6) respectively perform demodulation and despreading processing on the acquired signals, and a delay-dependent module (7) calculates the delay of the two paths of signals. The method ensures that additional delay caused byhardware is not introduced in the measuring process, and can ensure the delay measuring accuracy less than 500ps when the sampling rate is 4GSa/s.
Owner:中国航天科工集团第二研究院二〇三所
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