43results about How to "Reduce time synchronization requirements" patented technology

The invention discloses an OFDM (Orthogonal Frequency Division Multiplexing) data transmission method, which is used for transmitting uplink data in a short or medium distance in a wireless communication system and dividing an available band of the system into N basic sub-bands in advance. The method comprises the following steps: a transmitting station occupies M basic sub-bands and modulates data to the M basic sub-bands to transmit the data; and a receiving station receives one or more data from the transmitting station within the range of the N basic sub-bands, where M is less than or equal to N, and both M and N are positive integer. The invention further provides an OFDM-based data transmission system. By the combination of the OFDM technology and the sub-bands, different bandwidth configurations in the transmitting station and the receiving station of the wireless communication system are allowed; the transmitting station can be in a low configuration to reduce the hardware cost, while the receiving station can in a high configuration to improve the efficiency, spectral efficiency, throughput rate and the like and further implement simultaneous communication between an access point and a plurality of user stations.

The invention discloses a visible light communication method, sending device, receiving device and system. A sending end for visible light communication enables transmitted communication information to be modulated line by line to an original image signal to generate modulation image signals, and the modulation image signals are displayed in a line-by-line scanning manner; and a receiving end for visible light communication collects the modulation image signals, scans the modulation image signals line by line and demodulates the communication information in the modulation image signals. According to the technical scheme, the transmitted communication information is modulated to the original image signal line by line to generate the modulation image signals, and then, the modulation image signals are displayed in a line-by-line scanning manner, so that when the transmitted communication information is demodulated, the transmitted communication information of the lines can be demodulated as long as the lines in the modulation image signals are collected without capturing a complete image frame, and requirement for time synchronization of the visible light communication system can be reduced.

The invention, which belongs to the indoor positioning technology, disclosed a method for positioning a non-cooperative target by using channel pulse response autocorrelation sequence. The method comprises the following steps: establishing a location database; arranging positioning chips on each management object and storing each management object information parameter in the database; determining the positions of the management objects and displaying the current positions of all the management objects on a visual interface. In the invention, the channel pulse response autocorrelation sequence is used as a signal for establishing the database. After a receiver receives the signal, autocorrelation processing is performed respectively. And the processed signal and preset node position parameters which are relative to each signal receiver are used to establish the positioning database. In the method, more discrete time domain information is used, positioning information is abundant and positioning accuracy can be further raised. Compared to the background technology, the positioning accuracy by using the method of the invention can be raised more than 10%. Sensitivity to position differences in positioning areas and the positioning accuracy can be effectively raised. Requirements, such as time synchronism and the like, can be reduced.

The present invention relates to a method for channel quality estimation in a wireless data communication system, wherein data streams are transmitted from a transmitter having multiple antennas and / or antenna elements to a receiver over a frequency band, wherein, during a first period of time, data streams are transmitted on at least one sub-band of the frequency band using a first beamforming constellation, and wherein, during a subsequent second period of time, data streams are transmitted on said sub-band using a second beamforming constellation. The method further includes a training step, during the first period of time, wherein a data stream is transmitted on a portion of, or adjacent to, said sub-band while using the beamforming constellation to be used in said second period of time. The present invention also relates to a system, a transmitter and a communication system.

The invention belongs to the technical field of indoor positioning, and discloses an audio positioning method based on emission angle estimation. At least two base stations with known position information and attitude information are arranged, and each base station is equipped with an array of sound source emitters. The array includes several sound source transmitters that transmit sound signals in different directions; each base station continuously transmits sound signals with identification codes through the sound source transmitters, and the identification codes of the sound signals emitted by different sound source transmitters are uniquely determined and Different from each other; the receiving end receives all sound signals from all base stations, and demodulates the sound signals to obtain the angular probability distribution between the receiving end and the base station; according to the angular probability distribution, the best spatial estimation corresponding to the receiving end and each base station is obtained Angle: According to the best spatial estimation angle in the base station coordinate system, the position information and attitude information of the base station, the spatial position of the receiving end is obtained. The invention solves the problem of low accuracy of indoor positioning.

The embodiment of the present invention discloses an authentication method, device and storage medium. The method includes the terminal sending the first authentication request message carrying the token to the server; the server sending the first authentication response message to the terminal; Text, the second authentication request message of the target dynamic password is sent to the server, the target dynamic password is encrypted from the local registration parameters, original key and sequence data of the terminal, and the sequence ciphertext is encrypted from the sequence data; the server will carry the second authentication result of the authentication result The response message is sent to the terminal, and the authentication result is used to indicate that the target dynamic password is authenticated according to the serial ciphertext, the server's local original key and registration parameters. Symmetric key function and HMAC technology can be used for registration and authentication between the server and the terminal, which can increase the calculation speed and reduce the time and space overhead. The sequence data has low requirements for time synchronization, and is suitable for cross-border and cross-regional terminals and Authentication of the server.

As shown in FIG. 7, a data receiver receives video data and audio data together with a frequency division parameter N that depends on the pixel clock of the video data and the sampling frequency of the audio data, and a count value CTS that is obtained by counting the period of the audio clock that has been subjected to frequency division by the frequency division parameter N, with the pixel clock, which are transmitted from a data transmitter, and subjects the pixel clock to frequency division by the count value CTS, phase-control the divided clock (s501) in accordance with a phase comparison clock (s505) that is obtained by dividing an audio clock (s403) oscillated from a VCO (504) by the frequency division parameter N, thereby generating an audio clock (s403).Accordingly, the data transmitter and the data receiver can satisfactorily implement multiplexing of audio data and video data, and transmission of the multiplexed data using an existing DVI cable, with a simple structure.

The present invention provides a data transmission method based on OFDM, which is used for J transmitting sites to transmit data to a receiving site at the same time, J is a positive integer, including: the receiving site divides the available frequency band into N basic sub-bands, which are J The transmitting sites schedule Mj basic frequency sub-bands that are exclusive to each other, j ∈ [1, J], j is a positive integer; J transmitting sites perform IFFT processing on the OFDM data to be transmitted respectively, and the jth transmitting site performs IFFT processing on the data IFFT processing with a length of Mj×K points, the sample sampling rate used is Mj×fs; J transmitting sites respectively modulate the IFFT processed data, and the jth transmitting site modulates the data to Mj basic sub-bands ; J transmitting sites respectively transmit data on the exclusive Mj basic sub-bands; the receiving site simultaneously receives the data sent by J transmitting sites within the range of N basic sub-bands, and performs FFT processing of N×K points, The sample sampling rate used is N x fs. The method allows bandwidth-capable asymmetric communication while allowing simultaneous access by multiple users.

The present invention provides a data transmission method based on OFDM, which is used for J transmitting sites to transmit data to a receiving site at the same time, J is a positive integer, including: the receiving site divides the available frequency band into N basic sub-bands, which are J Transmitting sites schedule their exclusive Mj basic sub-bands, j∈[1, J], j is a positive integer; set the length of the system cyclic prefix to TCP≥2δ+τm, 2δ is the maximum coverage radius allowed by the signal from the transmitting site Experienced two-way propagation delay, τm multipath delay extension; J transmitting sites respectively add a cyclic prefix of TCP length to the data to be sent and modulate them to their exclusive Mj basic sub-bands; The data sent by J transmitting sites are simultaneously received within the range of the basic sub-band, and the data sent by each transmitting site is extracted according to the preset cyclic prefix whose length is TCP. The method allows bandwidth-capable asymmetric communication while allowing simultaneous access by multiple users.

The present invention relates to a satellite optical burst switching conflict resolution scheduling implementation system and method, according to the network topology of the space-based broadband transmission backbone network and the status of each switching node, through the scheduling mode of pre-allocation of network resources, in the space-based broadband transmission backbone network The boundary controls the data that will enter the space-based broadband transmission backbone network for transmission and exchange, pre-plans the exchange time and forwarding path of each optical burst data entering the space-based broadband transmission backbone network, and realizes the optical burst data exchange of the space-based broadband transmission backbone network conflict resolution scheduling. The optical burst data of the space-based broadband transmission backbone network is generated by the electrical domain. After the electrical-optical conversion is completed at the edge node of the backbone network, it enters the backbone network for optical burst exchange. After reaching the destination edge node, the optical-electrical conversion is completed, and then the data is sent to the processing terminal. , to complete the data routing exchange process. The system utilizes network resources to resolve conflicts in satellite optical burst switching through pre-planning and scheduling.