448 results about "Satellite mobile communication" patented technology

Communications of a mobile station with a satellite mobile communications system and a terrestrial mobile communications system are coordinated. The mobile station is registered with the terrestrial mobile communications system and, responsive to the registration of the mobile station with the terrestrial mobile communications system, the mobile station is concurrently registered with the satellite mobile communications system. The concurrent registration may include implicitly registering the mobile station with the satellite mobile communications system, e.g., by storing information identifying the mobile station may be stored in a location register of the satellite mobile communications system responsive to the registration of the mobile station with the terrestrial mobile communications system, and maintaining synchronization between the two registrations. Authentication tokens may be pre-generated for quick re-registration with a satellite mobile communications system.

An earth station receives a return signal via more than one satellite link from a mobile terminal using TDMA. The earth station selects one or more of the satellite links for transmitting a forward signal on the basis of the quality of signal received via each link. The earth section allocates frequency channels to the mobile terminals according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals which share the same frequency channel is approximately the same. The satellite includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas. In this way, beam-to-beam handover is reduced, while maintaining the boresight of the antenna pointing at the nadir.

A mobile communication system that supports Device to Device (D2D) communications, comprises: a base station that notifies a plurality of user terminals of a D2D common RNTI that is a radio network temporary identifier (RNTI) which is common in the plurality of user terminals, and that is used to collectively transmit, to the plurality of user terminals, a D2D control signal for controlling the D2D communications.

Communications between a terminal and a terrestrial base station are established. The terrestrial base station receives a request to monitor a satellite base station from the terminal. The terrestrial base station grants the request and receives monitoring information for the satellite base station corresponding to the request. Granting of the request may include suspending transmission from the terrestrial base station to the terminal for a period of time sufficient to allow the terminal to request the monitoring information from the satellite base station and receiving monitoring information may include receiving the requested monitoring information at the terrestrial base station via a communications path not including the terminal. Suspending transmission from the terrestrial base station to the terminal may be followed by resuming transmission to the terminal before receiving the monitoring information at the terrestrial base station. The communications path not including the terminal may include a terrestrial Access Service Network Gateway serving the terrestrial base station and a satellite Access Service Network Gateway serving the satellite base station. Handover techniques are also described.

The invention discloses an SC-OFDMA-based satellite mobile communication system for a forward link, which belongs to the field of satellite mobile communication. The SC-OFDMA-based system for the forward link is characterized in that single carrier signals of a user are mapped to different sub-carriers through DFT (discrete Fourier transform) or FFT (fast Fourier transform) and then subjected to IFFT (inverse fast Fourier transform) to realize orthogonal transmission of each user signal so as to improve the utilization rate of high frequency spectrum resources and reduce the peak-to-average power ratio of the satellite forward link; and in the multi-beam-based satellite mobile communication system, different sub-carrier groups are distributed to the users in a beam overlapped area according to the beams belonging to the users so as to reduce the co-channel interference between the low beams and fulfill the aim of improving the capacity of the system.

A random access method in a mobile communication system, the random access method for supporting random access with a cell size of about 100 kilometers (km) or more and a power limited terminal and a preamble structure thereof are provided. While a conventional long term evolution (LTE) random access preamble sequence is reused, a difference in a round-trip delay time between terminals in a large cell area may be compensated. Additionally, since higher power transmission is achieved per bandwidth, a higher link margin may be secured. Also, compatibility with resource scheduling of the conventional LTE may be maintained. Random access may be supported in a large cell, and a preamble structure of a satellite mobile communication may be implemented based on terrestrial LTE.

The invention provides a time advance compensation satellite mobile communication random access method and system and a medium, and the method comprises the steps: a downlink broadcast sending step: obtaining a cell formed by a wave beam of a satellite on the ground, obtaining the minimum TA in the cell, recording the minimum TA as TAmin, and enabling the satellite to send satellite position information and TAmin in the downlink broadcast; And a transmission delay calculation step: enabling the UE to receive the downlink broadcast, obtaining the satellite position information and the TAmin according to the received downlink broadcast, and calculating the difference value TAdiff of the TA estimated by the UE per se relative to the TAmin. In the random access process of the satellite, the transmission time delay is estimated in advance at the UE side and compensation is performed when the PRACH is sent, so that the problem of high time cost caused by long time delay in the random accessof the satellite is solved, and the consumption of uplink resources by the PRACH is greatly reduced.

The invention relates to a digital beam tracking method for a molecular matrix of a satellite mobile communication phased-array antenna. The digital beam tracking method is characterized by comprising the following steps: dividing a phased array into 4 quadrants, namely the first quadrant, the second quadrant, the third quadrant and the fourth quadrant, according to the rectangular coordinate system, wherein the beam direction of each unit in each quadrant is controlled by united phased control logic; each quadrant comprises a power combiner (1), power dividers (2) and a tracking and receiving module (3); signals of the 4 quadrants share a tracking signal processing module (6) and a power combiner (4); power synthesis is independently carried out to the signal of each quadrant by the respective sub-array power combiner (1) to form the power-synthesized signal; then each quadrant respectively divides the power-synthesized signal into two signals by the power divider (2) of each quadrant. The digital beam tracking method can stably and reliably track the satellite under high-speed movement shaking conditions of a carrier.

The invention provides an uplink signal timing synchronous prediction compensation method used for satellite mobile communication. The uplink signal timing synchronous prediction compensation method used for the satellite mobile communication comprises the following steps of: sending an uplink signal to a satellite end by a ground terminal and forwarding the uplink signal to a gateway station through a satellite; detecting a timing synchronous offset value and selecting a reasonable prediction algorithm to predict additional timing synchronous offset occurred soon because the terminal moves in the next detection period according to the detection and history detection results, by the gateway station; calculating the compensation value accordingly and notifying the ground terminal through a downlink synchronous adjustment instruction; and carrying out relevant compensation adjustment on sending time of an uplink signal of the terminal per se by the terminal after receiving the adjustment instruction so that the timing synchronous offset can be controlled in a smaller threshold all the time to ensure synchronous performance of a system. The uplink signal timing synchronous prediction compensation method used for the satellite mobile communication can be used for the next generation of mobile satellite communication system compatible with 3G/B3G (3rd generation/beyond 3rd generation) standards, and a workable solution for the problem of timing synchronous offset caused by long delay in a satellite communication system is provided.

The invention discloses a mobile communication system capable of providing wireless communication support to mobile users on sea ships. The system is combined by a honeycomb mobile communication network, a sea mobile self-organization network and a satellite mobile communication network through a sea satellite gateway, a ship honeycomb gateway and a land gateway. The system provides a plurality of communication methods to sea mobile users and land users. The sea mobile users and the land users can choose proper wireless communication network to build communication connection through a wireless network choosing method which is disclosed by the invention. The device and the method can reduce the deploying cost of the communication network and the communication cost of the mobile users, can expand the supported mobile terminal types, and can provide richer services to the sea mobile users.

The invention provides a satellite mobile communication method fused with a 5G network, and the method is characterized by comprising the following steps: carrying out the modeling of a satellite mobile communication scene, and carrying out the quantitative description of the system composition, a network structure, a communication link, a transmission system, and a working process; establishing high and low frequency networking; establishing satellite-ground cooperative cognitive wireless communication in a dynamic spectrum environment; performing high-dynamic compensation on Doppler frequency shift in mobile satellite communication; and realizing multi-user non-orthogonal multiple access in a mobile satellite communication environment. The method has the beneficial effects that the system effectively utilizes various spectrum resources to improve the data transmission rate and the system capacity; idle unlicensed spectrum is utilized by the system, and the problem of spectrum shortage is solved; the 5G air interface waveform is optimized to enable the 5G air interface waveform to adapt to high dynamic characteristics in a satellite communication scene; the spectrum utilization rate and the system capacity are effectively improved; the problems that a satellite mobile communication system is special in topology, difficult in routing and large in user service end-to-end time delay are effectively solved.

The invention discloses a satellite mobile communication system based on partial satellite baseband switching, which belongs to the technical field of satellite communication. The satellite mobile communication system comprises a communication network body branch and a satellite switching management control branch which are discrete and parallel. A management control signal of satellite switchingprocessing is produced and transmitted by the satellite switching management control branch. A satellite processor in the system has the complete function of satellite transparent forwarding between a user link and a feeding link and also supports partial communication business for realizing satellite single-hop connection in the mode of bridging a bypass. A communication interface, a protocol specification and a processing course of the prior ground mobile communication system are not corrected basically; the prior scheme of the ground user terminal can be directly adopted by a satellite user terminal without considering double-module/multiple-module terminal design requirements; and simultaneously, the satellite mobile communication system is convenient for the further upgrade of a communication network body of the satellite system along with the development of the network technique of the ground mobile communication system.

The invention belongs to the field of satellite mobile communication and relates to a circularly polarized antenna design, in particular to a circularly polarized dipole antenna for satellite communication. The circularly polarized dipole antenna has the advantages of wide band, wide wave beam and good low-elevation angle circular polarization performance. The circularly polarized dipole antenna comprises a dielectric substrate, a metal reflecting plate, four dipole antenna radiation arms, four parasitic patches, four metal conductive walls and a coaxial feeder; the conductive walls capable ofbroadening lobes are applied to the circularly polarized crossed dipole antenna in a combined manner; the metal reflecting ground plate, the conductive walls and the parasitic patches jointly form magnetic dipole antennas; lobe broadening is carried out on the basis of the complementation of the radiation patterns of the magnetic dipoles and the electric dipoles, so that gain at a low elevation angle can be improved; and thus, the circularly polarized dipole antenna for satellite communication has the advantages of wide band, wide wave beam, low elevation angle, good circular polarization performance, simple structure and easiness in installation, and is more suitable for satellite communication.

The invention relates to time slot synchronous system and method of GEO (geographic) satellite mobile communication based on 3G under a high dynamic environment. The time slot synchronous system comprises an antenna, a radio frequency circuit module, an A/D (Analogue to Digital) conversion module, an orthogonal down-conversion module, a low pass filter module and a numerical controlled oscillator module. The time slot synchronous system is characterized by comprising a matched filtering module, an FFT (Fast Fourier Transform) module and a carrier tracking module, wherein the key folded matched filtering module in the matched filtering module is designed based on equal capture velocity to save the hardware resources greatly. The FFT module and the carrier tracking module are combined so that the capture velocity to the carrier frequency is greater and more accurate. At the same time, by adopting the invention, time slot synchronization to a GEO satellite down-link channel can be realized under the high dynamic environment that Doppler frequency shift is 40KHz.

The invention discloses a terminal independent GEO satellite mobile communication system multi-beam switching method, which mainly relates to a cross-beam switching technology in the satellite mobilecommunication field. A dual channel device is arranged in the mobile terminal; through reasonable software control, the dual-channel devices can reside in different beams in the beam overlapping area,and the communication data can be seamlessly switched between the two channels when the beams are crossed, thus realizing the continuity of communication and the integrity of data transmission in theprocess of high-speed mobile users frequently crossing the beams. A terminal dual channel is adopted, the design of autonomous handoff transmission channel, compared with the existing cross-beam switching method, it has the characteristics of no system switching control, flexible and autonomous user use, uninterrupted communication and user non-inductive beam switching, and is especially suitablefor the GEO multi-beam satellite system where the mobile user can move freely and keep the communication continuity.

The invention discloses a low-profile highly-integrated satellite mobile communication phased-array antenna which comprises an antenna framework, an antenna unit, a radio-frequency circuit, a wave control, a power device and the like. By the aid of a full-plane structural form, the height of the antenna is reduced, the integrated level of the antenna is improved, the antenna unit is provided with an ultralow-profile micro-strip, the radio-frequency circuit, a feed network, the wave control and a power lamp are provided with tile-type structures, space size is effectively used, space wave beams are scanned by the aid of phased-array technology, and the antenna is high in efficiency.

The invention discloses an adaptive virtual hybrid retransmission method applicable to a satellite mobile communication system. Firstly, a receiving end forecasts and estimates the channel quality during signal sending at a sending end according to a received pilot signal, jointly selects a correct transmission encoding and modulation mode with the maximum rate and a plurality of redundant versions of the same encoding block, which are sent at one time, and feeds back a selection result to the sending end; the sending end calculates the length of a transmission block on the basis of the number of available resource particles according to the selected encoding and modulation mode and an equivalent code rate corresponding to the number of the redundant versions of the encoding block, which are sent at one time, to finish channel encoding, rate matching and modulation; a channel adaptively sends one or more redundant versions at one time in a given time frequency resource block; and finally, the receiving end receives data, and then combines and decodes a plurality of possibly sent redundant versions according to a hybrid automatic repeat request (HARQ) decoding mode. By using the method, the reliability of a link is improved; and the method is applicable to the satellite mobile communication system which is large in transmission time delay and has a power limitation characteristic.

The invention discloses a multi-channel demodulation signal processing platform based on a CPCI (compact programmable communication interface). The demodulation signal processing platform comprises a multi-channel intermediate-frequency signal receiving module; the multi-channel intermediate-frequency signal receiving module can be connected with at least one A/D (analog/digital) conversion module and at least one DDC (direct digital control) digital down converter module; the DDC digital down converter module is connected with an FPGA (field programmable gate array) module; and the FPGA module is connected with a DSP (digital signal processor) module and a CPCI module. By using the multi-channel demodulation signal processing platform based on the CPCI, which is provided by the invention, the analog signal reception and the digital signal sending are integrated into a whole; the parallel and independent A/D conversion module and a DDC digital down converter passage are adopted; at least one intermediate-frequency signal of satellite mobile communication can be received; the multi-channel demodulation signal processing is realized; and the signal processing platform is compatible with signal processing techniques with different modes, different systems and different speed rates, and has stronger practicability.

The invention discloses a constellation satellite system and a communication method and system based on the same. The constellation satellite system comprises terminals, constellation satellites, a gateway station, and a cluster core network. The terminals comprise various types of cluster user terminals. The constellation satellites comprise a plurality of LEO (low earth orbit) or MEO (medium earth orbit) satellites which cover the whole globe, and the constellation satellites form a constellation. The gateway station is used for completing the access of the network of the constellation satellites to the cluster core network. The cluster core network comprises a cluster user group, the registration of the group members, the discrimination of the authority of the users and business, the call processing, the charging management and the scheduling management. The cluster corn network irons out the defects of ground wireless cluster communication, and a global wireless cluster network transmission trunk line is built through a constellation satellite mobile communication network, and the emergency command communication capability of a wireless cluster is effectively extended. Meanwhile, the constellation satellite system is good in emergency adaptability, convenience and economical performances.

The invention discloses a satellite communication system user link interference avoidance method based on a spectrum map in order to solve the problem how to realize reliable communication for a satellite mobile communication system in a complex electromagnetic environment. The method is implemented by the following technical scheme: the five links of data acquisition and preprocessing, spectrum map construction and distribution, spectrum availability prediction, interference avoidance decision generation and satellite-ground joint spectrum resource allocation are adopted; a user terminal anda satellite acquire the spectrum map information of the user links of a satellite mobile communication system together and report the information to a gateway station; the gateway station establishesand distributes a regional spectrum map to a network management center, and the network management center constructs a complete spectrum map of the satellite mobile communication system; the network management center uses a frequent pattern mining algorithm to predict the spectrum availability and sends a generated interference avoidance strategy to the gateway station; and the gateway station generates a resource allocation instruction, and the satellite and the user terminal reconfigure parameters according to the allocation instruction to complete system interference avoidance.

The invention discloses a method and a device for carrier tracking in satellite mobile communication and relates to the field of communication. The method and the device can realize the tracking of carriers with frequency which changes quickly in the satellite mobile communication. The method disclosed by the invention mainly comprises of realizing frequency offset estimation of received signals by inserting a certain quantity of symbol training sequences in bursts in a carrier tracking loop for the satellite mobile communication, obtaining the approximate frequency offset estimation values of the received signals, bringing the approximate frequency offset estimation values into a loop filter for filtering to obtain filtered frequency offset estimation values, and adjusting a VCO (Voltage Controlled Oscillator) of the filter in the carrier tracking loop through the filtered frequency offset values to realize the carrier tracking of the satellite mobile communication. The method and the device for the carrier tracking in the satellite mobile communication disclosed by the embodiment of the invention are mainly used for the carrier tracking process in the satellite mobile communication.

The invention relates to a network access authentication method applicable to a satellite mobile communication network. The network access authentication method comprises four steps of user registration, user management, mobile authentication and update of authentication; an effective network access authentication protocol is of great importance for the security of the satellite mobile communication network. The network access authentication method is characterized in that the authentication role of a gateway station is emphasized and the authentication calculation load of an NCC (Network Control Center) is reduced; common attacks such as masquerading, tampering and replay of any party can be resisted, and meanwhile, integrity protection on the transmitted data is realized, and therefore, the security of the satellite mobile communication network is greatly improved.

The embodiment of the invention discloses a communication network switching method and device, electronic equipment and a storage medium. The method for switching a communication network from a groundmobile communication network to a satellite mobile communication network comprises the steps that the current position of a terminal is acquired, and the current positions of satellites in a satellite mobile communication network are acquired; a plurality of satellites closest to the terminal are determined according to the current position of the terminal and the current positions of the satellites; a control terminal measures the signal intensity of the plurality of satellites, and determines the satellite with the highest signal intensity in the plurality of satellites as a target satellite to be switched; and reserved uplink channel information of the target satellite is acquired, and a network switching request signaling carrying a target satellite identifier and the reserved uplinkchannel information of the target satellite is initiated to the terminal. According to the embodiment of the invention, seamless switching of the terminal between the ground mobile communication network and the satellite mobile communication network can be realized, and the stability and continuity of terminal service can be improved.

The invention provides a realization method and a device for an action-based satellite mobile communication gateway station. The realization method comprises: air interface link of the gateway station for communicating with the satellite uses a user link of a satellite mobile communication system, and the gateway station accesses a ground core network through a broadband wireless access mode; the gateway station initiates a registration process to the satellite and the ground core network after starting up and the satellite identifies the gateway station as a gateway station backhaul device after the registration of the satellite is succeeded; for the downlink of the satellite, the satellite transmits the data pack which is needed to be transponded to the gateway station through the user link; the base station transponds the data pack to the ground core network through the wireless broadband base station; for the satellite uplink, the ground core networks transmits the data pack which is needed to be transponded to the gateway through the wireless broadband base station; and the gateway station transponds the data pack to the satellite through the user link. The invention also provides an action-based satellite mobile communication gateway station device.