CN106413075B - Method and system for clock synchronization and end station - Google Patents
Method and system for clock synchronization and end station Download PDFInfo
- Publication number
- CN106413075B CN106413075B CN201510483653.4A CN201510483653A CN106413075B CN 106413075 B CN106413075 B CN 106413075B CN 201510483653 A CN201510483653 A CN 201510483653A CN 106413075 B CN106413075 B CN 106413075B
- Authority
- CN
- China
- Prior art keywords
- time
- station
- master station
- wireless signal
- time information
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
- H04W56/0015—Synchronization between nodes one node acting as a reference for the others
Abstract
The invention provides a clock synchronization method, a clock synchronization system and an end station, which are applied to the field of communication. The method comprises the steps that an end station receives a wireless signal forwarded by a main station through a digital broadcast satellite, wherein the wireless signal comprises main station time information; the end station extracts the time information of the main station from the wireless signal; and the end station performs clock synchronization with the master station according to the master station time information. Compared with the prior art, the time information of the master station is directly carried in the wireless signal sent by the master station without being synchronized by a GPS, so that the clock synchronization of the master station and the end station can be realized based on the actual modulation encoder and the receiving demodulation decoder for network communication between the master station and the end station, the need of installing a GPS receiver is avoided, and the cost can be reduced; furthermore, the master station and the end station directly perform clock synchronization, so that the signal strength is good, and the problem of weak signal strength caused by high altitude of a GPS satellite can be avoided.
Description
Technical Field
The invention relates to the field of communication, in particular to a method and a system for clock synchronization and an end station.
Background
On a ship going offshore, communication with the land is required to be maintained when the ship goes out offshore for a long time, but wired communication cannot be used due to the limitation of marine environment, communication between terminals on the ground and the ship can be realized only in a satellite forwarding mode, and various Base stations based on satellite communication, such as a Base Transceiver Station (BTS) or other types of Base stations, are available.
The BTS base station is a base station based on a Multi-Frequency Time Division multiple access (multiple Time Division multiple access) mode, and in the working process of the BTS base station, the clock synchronization or the Frequency synchronization of an end station and a master station needs to be maintained, and if the Frequency deviation between the end station and the master station is large, Frequency deviation is caused, so that a user cannot access the base station, and even faults such as call drop, call overtime and the like occur. Currently, clock synchronization of BTS base stations is implemented by using a Global Positioning Satellite (GPS) receiver, but the use of the GPS receiver for clock synchronization (frequency synchronization) has the following disadvantages: it is necessary to receive signals from at least three satellites in the sky above to ensure that the GPS receiver is in normal use. Certainly, when synchronization is needed, the overhead cannot always be "a whole blue sky", so that insufficient signal strength is one of the hardnesses of the GPS. Installing a GPS receiver at the BTS base station increases the cost.
Disclosure of Invention
The invention provides a method, a system and an end station for clock synchronization, and solves the problems of high cost and poor signal strength caused by the fact that a GPS receiver needs to be installed when the GPS is used for clock synchronization in the prior art.
In order to solve the above problem, the present invention provides a clock synchronization method, including:
an end station receives a wireless signal forwarded by a main station through a digital broadcast satellite, wherein the wireless signal comprises the time information of the main station;
the end station extracts the master station time information from the wireless signal;
and the end station performs clock synchronization with the master station according to the master station time information.
In an embodiment of the present invention, the master station time information includes:
the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite;
or the like, or, alternatively,
the master station time information includes a transmission time and a transmission delay time at which the master station transmits the radio signal to the digital broadcast satellite.
In one embodiment of the present invention, when the master station time information includes a transmission time at which the master station transmits the radio signal to the digital broadcast satellite; the extracting, by the end station, the master station time information from the wireless signal includes: the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite; the clock synchronization between the end station and the master station according to the master station time information comprises: the end station acquires transmission delay time; adding the sending time and the transmission delay time to obtain a sum as a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
In one embodiment of the present invention, when the master station time information includes a transmission time and a transmission delay time at which the master station transmits the radio signal to the digital broadcast satellite; the extracting, by the end station, the master station time information from the wireless signal includes: the end station extracts the time information of the main station from the wireless signals, and the transmission time and the transmission delay time of the wireless signals transmitted to the digital broadcast satellite by the main station are extracted by the end station; the clock synchronization between the end station and the master station according to the master station time information comprises: adding the sending time and the transmission delay to obtain a sum as a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
In an embodiment of the present invention, before setting the local time of the end station as the synchronization standard time, the method further includes: acquiring the receiving time of the wireless signal; judging whether the receiving time is the same as the synchronous standard time or not; and if the time difference is different, the local time of the end station is set as the synchronization standard time.
In one embodiment of the present invention, the data format of the wireless signal is a data frame; the data frame comprises a data head of a serial description data bus; the acquiring a reception time of receiving the wireless signal includes: and taking the time when the end station identifies the data head of the serial description data bus to be output as the receiving time.
In one embodiment of the present invention, the data format of the wireless signal is a data frame; the data frame comprises a data body of valid data on a data bus; the extracting, by the end station, the master station time information from the wireless signal includes: and analyzing the data main body of the effective data on the data bus to obtain the master station time information.
In order to solve the above problem, the present invention further provides a clock synchronization method, including:
the method comprises the steps that a master station transmits a wireless signal forwarded by a digital broadcast satellite to an end station, wherein the wireless signal comprises master station time information;
the end station receives the wireless signal;
the end station extracts the master station time information from the wireless signal;
and the end station performs clock synchronization with the master station according to the master station time information.
In order to solve the above problem, the present invention further provides an end station, which includes an obtaining module, an extracting module, and a synchronizing module:
the acquisition module is used for receiving a wireless signal forwarded by a master station through a digital broadcast satellite, wherein the wireless signal comprises master station time information;
the extraction module is used for extracting the master station time information from the wireless signals;
and the synchronization module is used for carrying out clock synchronization with the master station according to the master station time information.
In an embodiment of the present invention, the master station time information includes:
the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite;
or the like, or, alternatively,
the master station time information includes a transmission time and a transmission delay time at which the master station transmits the radio signal to the digital broadcast satellite.
In one embodiment of the present invention, when the master station time information includes a transmission time at which the master station transmits the radio signal to the digital broadcast satellite; the extracting module is further configured to extract the master station time information from the wireless signal, including: the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite; the synchronization module is further used for acquiring transmission delay time; adding the sending time and the transmission delay time to obtain a sum as a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
In one embodiment of the present invention, when the master station time information includes a transmission time and a transmission delay time at which the master station transmits the radio signal to the digital broadcast satellite; the extracting module is further configured to extract the master station time information from the wireless signal, including: the transmission time and the transmission delay time of the wireless signal transmitted by the main station to the digital broadcast satellite; the synchronization module is further used for adding the sending time and the transmission delay time to form a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
In an embodiment of the present invention, the synchronization module is further configured to acquire a receiving time for receiving the wireless signal before the local time of the end station is set as the synchronization standard time; judging whether the receiving time is the same as the synchronous standard time or not; and if the time difference is different, the local time of the end station is set as the synchronization standard time.
In order to solve the above problem, the present invention further provides a system for clock synchronization, which is characterized by comprising a master station and an end station:
the master station is used for transmitting a wireless signal forwarded by a digital broadcast satellite to the end station, and the wireless signal comprises the master station time information;
the end station is used for receiving the wireless signals and extracting the master station time information from the wireless signals; and carrying out clock synchronization with the master station according to the master station time information.
The invention has the beneficial effects that:
according to the clock synchronization method, the clock synchronization system and the end station, the end station receives the wireless signals forwarded by the main station through the digital broadcast satellite, and the wireless signals comprise the time information of the main station; the end station extracts the time information of the main station from the wireless signal; and the end station performs clock synchronization with the master station according to the master station time information. Compared with the prior art, the time information of the master station is directly carried in the wireless signal sent by the master station without being synchronized by a GPS, so that the clock synchronization of the master station and the end station can be realized based on the actual modulation encoder and the receiving demodulation decoder for network communication between the master station and the end station, the need of installing a GPS receiver is avoided, and the cost can be reduced; furthermore, the master station and the end station directly perform clock synchronization, so that the signal strength is good, and the problem of weak signal strength caused by high altitude of a GPS satellite can be avoided.
Drawings
Fig. 1 is a flowchart of a clock synchronization method according to an embodiment of the present invention;
FIG. 2-1 is a flowchart of a clock synchronization method according to a second embodiment of the present invention;
fig. 2-2 is a frame structure diagram of a frame in the clock synchronization method according to the second embodiment of the present invention;
fig. 2-3 are schematic diagrams illustrating connection between a tuner and a demodulator chip on an end station in the method for clock synchronization according to the second embodiment of the present invention;
fig. 2-4 are flow charts of analyzing data signals at the end station in the clock synchronization method according to the second embodiment of the present invention;
fig. 2-5 are schematic diagrams illustrating a time sequence of serially describing data bus output signals in the clock synchronization method according to the second embodiment of the present invention;
fig. 2-6 are schematic timing sequence diagrams of data bus output signals in the clock synchronization method according to the second embodiment of the invention;
fig. 2-7 are flow charts of forming a synchronous clock sequence in the clock synchronization method according to the second embodiment of the present invention;
fig. 3 is a schematic structural diagram of an end station according to a third embodiment of the present invention;
fig. 4 is a schematic structural diagram of a clock synchronization system according to a third embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment is as follows:
as shown in fig. 1, a method for clock synchronization in an embodiment of the present application includes:
s101: the method comprises the steps that an end station receives a wireless signal forwarded by a main station through a digital broadcast satellite, wherein the wireless signal comprises main station time information;
in this step, the digital broadcasting satellite mainly refers to a satellite that is transmitted as DVB-S (digital video broadcasting System for satellite broadcasting) and DVB-S2(second generation DVB System for satellite broadcasting and reporting) for more efficient bandwidth utilization, the wireless signal mainly refers to a wireless signal for transmitting high-quality video and high-level services through the satellite, and the master station time information refers to all times that can be used for clock synchronization of the end station. Preferably, the master station time information includes a time at which the master station transmits the radio signal. The time at which the radio signal is to be transmitted is carried in the radio signal, where the end station is allowed to perform clock synchronization based on the time. Specifically, because a certain delay time exists between the end station and the master station, the end station still needs to know the delay time between the end station and the master station after obtaining the time for transmitting the wireless signal, generally, the delay time is a relatively fixed value, the end station can obtain a synchronous time according to the time for transmitting the wireless signal and the delay time, and then the local clock is synchronized according to the synchronous time. Further, in order to facilitate the end station to directly perform clock synchronization, the master station time information further includes delay time of the wireless signal reaching the end station, that is, the time for sending the wireless signal and the delay time are directly carried in the wireless signal, so that the end station directly obtains subsequent clock synchronization. The wireless signals refer to various signals capable of carrying master station time information, and the data format of the specific wireless data signals can be data messages, data packets, data frames and the like.
S102: the end station extracts the time information of the main station from the wireless signal;
in this step, since the master station time information is carried in the radio signal, the radio signal is processed to obtain the corresponding master station time information in order to specifically obtain the master station time information. Specifically, as the ground master station accesses the internet through the gateway, on the master station, original data messages are encapsulated into a format of DVB-S2, the data messages are modulated to frequency points corresponding to satellites through a modulator, the master station generates radio frequency signals and sends the radio frequency signals to a satellite transponder through an antenna, and the signals are amplified through the transponder and forwarded to an end station on a ship; the end station receives the radio frequency signal, changes the radio frequency signal into a baseband signal through down conversion, and then restores original data through demodulation and decoding. The method for clock synchronization of claim 1, wherein the receiving by the end station of the radio signal retransmitted by the master station via the digital broadcast satellite comprises: the end station receives a radio frequency signal corresponding to the wireless signal forwarded by the main station through the digital broadcast satellite; the end station carries out signal conversion processing on the radio frequency signal to obtain a corresponding digital orthogonal signal; and the end station demodulates and decodes the digital orthogonal signal to obtain a corresponding wireless signal. The wireless signal includes a data body of valid data on the data bus; the data body of the valid data on the data bus comprises master station time information; the step of analyzing the wireless signals by the end station to obtain the time information of the main station comprises the following steps: master time information is parsed from the data body of valid data on the data bus.
S103: and the end station performs clock synchronization with the master station according to the master station time information.
In this step, specifically, clock synchronization may be performed on the local clock of the end station directly according to the master station time information; i.e. the synchronization with the master's clock is performed regardless of whether the local clock is in error. There may be a large number of synchronization operations, and in order to reduce this part of the processing, it is preferable to first determine whether the local clock of the end station is the same as the clock of the master station, and if not, perform clock synchronization. That is, the local clock is only clocked when the master clock is not synchronized. Specifically, determining whether the local clock of the end station is the same as the master station clock includes: acquiring the receiving time of receiving a wireless signal; and judging whether the local clock is the same as the master clock or not according to the master time information and the receiving time. Further, in the normal processing process, the end station performs related processing after receiving the wireless signal to obtain specific master station time information, a certain delay is provided in the processing process, and the delay time is difficult to determine, in order to accurately determine the receiving time of the specific received wireless signal and reduce the judgment error, preferably, the wireless signal includes a data header of a serial description data bus; acquiring the reception time of the received wireless signal includes: the time at which the end station recognizes the data header of the output serial description data bus is taken as the reception time. That is, after receiving the wireless signal, the end station can immediately recognize the data head of the output serial description data bus without subsequent processing, so that the specific time of receiving the wireless signal can be well determined, and other ways of determining the time of the wireless signal can be realized.
Further, in order to ensure that the clocks between the master station and the end station are synchronized at any time, that is, the master station may send the radio signals continuously forwarded by the digital broadcast satellite to the end station, preferably, the master station sends the radio signals continuously forwarded by the digital broadcast satellite to the end station according to a preset period, where in order to reduce the overhead of the physical layer and achieve the purpose of network synchronization, the master station sends the radio signals with the master station time information with a preset period of 80 milliseconds. Then the end station periodically obtains the wireless signals, and in order to facilitate subsequent time synchronization of the master station time information corresponding to the wireless signals, preferably, a synchronous clock sequence is formed; specifically, the synchronous clock sequence formed according to the number of the wireless signals may be that each wireless signal further includes a data body describing a data bus in series and a data body describing valid data on the data bus; the data body of the serial description data bus comprises a first physical frame counter; the data main body of the effective data on the data bus comprises a second physical frame counter and master station time information; forming the synchronized clock sequence according to how many wireless signals include: forming a queue according to the first physical frame counter of each wireless signal; finding out corresponding second physical frame counters according to the first physical frame counters; and finding the data main body of the effective data on the corresponding data bus according to each second physical frame counter, and extracting each master station time information from the data main body of the effective data on the data bus to form a synchronous clock sequence. For example, the wireless signal is a data frame, before the end station receives, demodulates and decodes, the arriving SOF frame header part is detected, then the NCR of the master station is analyzed from the frame data part, the synchronization timestamp of the master station is known, the SOF sequence corresponding to the NCR information received periodically forms a stable synchronization clock sequence, then the synchronization can be processed like a common base station, and the synchronization clock sequence is sent to a phase-locked loop for calibration, so that the aim of keeping clock synchronization with the master station can be fulfilled instead of a GPS.
Specifically, the master station time information includes: the transmission time or the master station time information for the master station to transmit the radio signal to the digital broadcast satellite includes the transmission time and the transmission delay time for the master station to transmit the radio signal to the digital broadcast satellite.
When the master station time information comprises the sending time of the master station sending the wireless signal to the digital broadcasting satellite; the step of extracting the master station time information from the wireless signal by the end station comprises the following steps: the end station extracts the sending time of the main station time information main station sending the wireless signal to the digital broadcasting satellite from the wireless signal; the end station carries out clock synchronization with the master station according to the master station time information and comprises: the end station acquires the transmission delay time; adding the sending time and the transmission delay to obtain the sum as a synchronous standard time; and setting the local time of the end station as the synchronous standard time.
When the master station time information comprises the sending time and the transmission delay time of the master station for sending the wireless signals to the digital broadcast satellite; the step of extracting the master station time information from the wireless signal by the end station comprises the following steps: the end station extracts the sending time and the transmission delay time of the main station time information main station sending the wireless signals to the digital broadcasting satellite from the wireless signals; the end station carries out clock synchronization with the master station according to the master station time information and comprises: adding the sending time and the transmission delay to obtain the sum as a synchronous standard time; and setting the local time of the end station as the synchronous standard time.
Further, before setting the local time of the end station as the synchronization standard time, the method further comprises the following steps: acquiring the receiving time of receiving a wireless signal; judging whether the receiving time is the same as the synchronous standard time or not; if not, the local time of the end station is set as the synchronous standard time.
Specifically, the data format of the wireless signal is a data frame; the data frame comprises a data head of a serial description data bus; acquiring the reception time of the received wireless signal includes: the time at which the end station recognizes the data header of the output serial description data bus is taken as the reception time.
Specifically, the data format of the wireless signal is a data frame; the data frame includes a data body of valid data on the data bus; the step of extracting the master station time information from the wireless signal by the end station comprises the following steps: master station time information is parsed from the data body of the valid data on the data bus.
Example two:
as shown in fig. 2-1, the method for clock synchronization in the embodiment of the present application includes:
s201: the method comprises the steps that a master station periodically transmits a wireless signal through a digital broadcast satellite, wherein the wireless signal comprises master station time information;
in this step, specifically, taking a data frame as an example, the DVB-S2 frame after modulation coding and encapsulation at the primary station is shown in fig. 2-2, and the frame header portion is divided into an SOF section and a plsc (physical layer signaling code) section, where xfecframe (complex Forward Error Correction frame) represents the data portion. The frame header has 90 symbols, wherein the SOF occupies 26 symbols, and is converted into 18D2E82HEX with hexadecimal, the data information is fixed and unchangeable in the DVB-S2 protocol, and for the characteristic of the frame format of the DVB-S2 protocol, we can pack the network Clock reference NCR (network Clock reference) in XFECFRAME at the primary station, and periodically transmit the data frame carrying the NCR. The network clock reference is a specific example of the master station time information, but other clock information is also possible.
S202: the end station receives the wireless signal, analyzes the wireless signal to obtain the time information of the main station according to the digital signal and forms a synchronous clock sequence;
s203: and the end station performs clock synchronization with the master station according to the synchronous clock sequence.
In the step S202, specifically, at the receiving end station, we use a separate Tuner and demodulation chip Demod, 2-3, which is a connection schematic of the Tuner and demodulator chip at the end station. It is recommended here that the STV6111B plus STV0910ADB chipset of Italian semiconductor, Inc., and that the external controllers uController and Tuner and Demod communicate according to the I2C (Inter-Integrated Circuit) protocol. Tuner is responsible for shifting the radio frequency signal received by the antenna to near zero frequency and then sending the analog quadrature iq (phase and quadrature) signal to Demod. The whole processing flow of Demod is shown in fig. 2-4, which is a flow chart for analyzing wireless signals at the end station in the clock synchronization method, specifically a flow chart for analyzing and matching serial description data sdd (serial data description) bus SOF and valid data on the data bus at the end station, in the Demod, the Analog IQ signal is sampled and quantized by the Analog-to-Digital Converter ADC (Analog-to-Digital Converter) to be converted into a Digital IQ signal, then, after demodulation and decoding, the transport stream manager outputs the original DATA frame on the DATA bus by the transport stream manager, the DATA bus includes the output timing CLKOUT, the valid DATA STROUT and D/P on the DATA bus, the valid DATA main body DATA on the DATA bus, etc., fig. 2 to 5 show specific timing charts of the data header strobe _ SOF including valid data on the data bus among the valid data strobe on the data bus.
To properly cause Demod to output SOF, we can select the fixed GPIO pin as the SDD bus output by configuring the general Purpose Input output GPIO (general Purpose Input output) switch matrix of fig. 2-3, the SDD bus outputs the header SDD _ SOF, Symbol Clock, and the body SD _ data of the serial description data bus, with the SDD bus output signal timing as shown in fig. 2-6.
Because the radio signal is transmitted from the main station to the satellite and then received from the satellite to the end station, the propagation delay exists in the middle process. In addition, in the receiving end processing process, the internal processing of Tuner and Demod also brings hardware operation delay, and we hope that all the delays are added up to be a fixed value, so that the end station processing does not introduce too large error.
In contrast to fig. 2-5 and 2-6, it is noted that the data bus STROUT also has a start frame STROUT _ SOF, which indicates that the entire DVB-S2 data frame is demodulated and decoded for output, while the SOF on the SDD bus is that the DVB-S2 data header is recognized, i.e., output, without subsequent demodulation and decoding. It is known that DVB-S2 supports four demodulation modes, i.e., code rate ranging from 1/4 to 9/10, QPSK, 8PSK, 16PSK and 32APSK, and the time taken for combining different code rates and demodulation modes varies. If we use the SOF on STROUT as the timing synchronization clock source, because the physical frame lengths under different code rates are different, the processing delay is not fixed due to different demodulation modes, so the reached time point is not a fixed value, and the SOF on the SDD bus is used for clock synchronization.
At the transmitting end of the master station, SOF and DATA XFECFRAME on a single frame are in one-to-one correspondence, however, at the receiving end of the end station, DATA header SDD _ SOF of the serial description DATA bus is output on the SDD bus, DATA is output on the DATA bus DATA, SOF and DATA output time of the same frame are also deviated, SOF always precedes DATA, in order to ensure that SOF and DATA are not misplaced, we find that SD _ DATA and DATA bus DATA both have a counter PLFRAME _ counter indicating which physical frame belongs to currently, extract these two fields, and then compare them, so as to determine whether DATA header SDD _ SOF and DATA of the serial description DATA bus are the same frame, as shown in fig. 2-7 specifically, including:
step S2021: opening two large enough Buffer buffers, and continuously receiving SDD _ SOF, SD _ DATA and STROUT and DATA on a DATA bus;
specifically, Buffer0 reads SOF and SD _ data on the SDD bus; buffer1 reads STROUT _ SOF, DATA on the DATA bus.
Step S2022: obtaining the accurate frame arrival time from the SDD _ SOF timestamp, extracting a counter PLFRAME _ counter 1 of a first physical frame in the SD _ data, and storing the counter PLFRAME _ counter 1 in a queue;
step S2023: a counter PLFRAME _ counter 2 for extracting DATA from DATA and extracting a second physical frame contained in the DATA when the DATA bus detects STROUT _ SOF;
step S2024: comparing the PLFRAME _ COuter2 with the PLFRAME _ COuter1 in the queue, if the sizes are equal, judging that the frame is the same frame, if the two PLFRAME _ COuters have a difference value, moving the corresponding step size in the queue according to the difference value, and finding the corresponding SDD _ SOF of the current data in the queue.
Example three:
the embodiment of the present application provides an end station 300, as shown in fig. 3, including an obtaining module 301, an extracting module 302, and a synchronizing module 303: the acquisition module 301 is configured to receive a wireless signal forwarded by a master station through a digital broadcast satellite, where the wireless signal includes master station time information; the extracting module 302 is configured to extract master station time information from the wireless signal; the synchronization module 303 is configured to perform clock synchronization with the master station according to the master station time information.
Specifically, the master station time information includes: the transmission time or the master station time information for the master station to transmit the radio signal to the digital broadcast satellite includes the transmission time and the transmission delay time for the master station to transmit the radio signal to the digital broadcast satellite.
Specifically, when the master station time information includes the transmission time of the master station for transmitting the radio signal to the digital broadcast satellite; the extracting module 302 is further configured to extract, from the wireless signal, a transmission time of the master station time information for the master station to transmit the wireless signal to the digital broadcast satellite; the synchronization module 303 is further configured to obtain a transmission delay time; adding the sending time and the transmission delay to obtain the sum as a synchronous standard time; and setting the local time of the end station as the synchronous standard time.
Specifically, when the master station time information includes the transmission time and the transmission delay time of the master station for transmitting the wireless signal to the digital broadcast satellite; the extraction module is also used for extracting the sending time and the transmission delay time of the main station time information main station sending the wireless signals to the digital broadcast satellite from the wireless signals; the synchronization module is also used for adding the sending time and the transmission delay to form a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
Further, the synchronization module 303 is further configured to obtain a receiving time of the received wireless signal before the local time of the end station is set as the synchronization standard time; judging whether the receiving time is the same as the synchronous standard time or not; if not, the local time of the end station is set as the synchronous standard time.
The embodiment of the present application provides a system for clock synchronization, which includes a master station 400 and an end station 300:
the master station 400 is configured to transmit a radio signal to the end station 300 via a digital broadcast satellite, where the radio signal includes master station time information;
the end station 300 is used for receiving wireless signals and extracting master station time information from the wireless signals; and carrying out clock synchronization with the master station according to the master station time information.
It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by instructing the relevant hardware through a program, and the program may be stored in a computer readable storage medium, such as a read-only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, each module/unit in the above embodiments may be implemented in the form of hardware, and may also be implemented in the form of a software functional module. The present invention is not limited to any specific form of combination of hardware and software.
The above embodiments are merely to illustrate the technical solutions of the present invention and not to limit the present invention, and the present invention has been described in detail with reference to the preferred embodiments. It will be understood by those skilled in the art that various modifications and equivalent arrangements may be made without departing from the spirit and scope of the present invention and it should be understood that the present invention is to be covered by the appended claims.
Claims (14)
1. A method of clock synchronization, comprising:
an end station receives a wireless signal forwarded by a main station through a digital broadcast satellite according to a preset period, wherein the wireless signal comprises the time information of the main station, and the digital broadcast satellite adopts DVB-S2 for transmission;
the end station extracts the master station time information from the wireless signal;
and the end station performs clock synchronization with the master station according to the master station time information.
2. The method of clock synchronization of claim 1, wherein the master time information comprises:
the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite;
or the like, or, alternatively,
the master station time information includes a transmission time and a transmission delay time at which the master station transmits the radio signal to the digital broadcast satellite.
3. The method for clock synchronization of claim 2, wherein when the master station time information includes a transmission time of the master station transmitting the radio signal to the digital broadcast satellite; the extracting, by the end station, the master station time information from the wireless signal includes: the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite; the clock synchronization between the end station and the master station according to the master station time information comprises: the end station acquires transmission delay time; adding the sending time and the transmission delay time to obtain a sum as a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
4. The method for clock synchronization of claim 2, wherein when the master station time information includes a transmission time and a transmission delay time of the master station transmitting the radio signal to the digital broadcasting satellite; the extracting, by the end station, the master station time information from the wireless signal includes: the transmission time and the transmission delay time of the wireless signal transmitted by the main station to the digital broadcast satellite; the clock synchronization between the end station and the master station according to the master station time information comprises: adding the sending time and the transmission delay time to obtain a sum as a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
5. The method for clock synchronization according to claim 3 or 4, further comprising, before setting the local time of the end station to the synchronization standard time: acquiring the receiving time of the wireless signal; judging whether the receiving time is the same as the synchronous standard time or not; and if the time difference is different, the local time of the end station is set as the synchronization standard time.
6. The method for clock synchronization according to claim 5, wherein the data format of the wireless signal is a data frame; the data frame comprises a data head of a serial description data bus; the acquiring a reception time of receiving the wireless signal includes: and taking the time when the end station identifies the data head of the serial description data bus to be output as the receiving time.
7. The method for clock synchronization according to claim 1, wherein the data format of the wireless signal is a data frame; the data frame comprises a data body of valid data on a data bus; the extracting, by the end station, the master station time information from the wireless signal includes: and analyzing the data main body of the effective data on the data bus to obtain the master station time information.
8. A method of clock synchronization, comprising:
the method comprises the steps that a main station transmits a wireless signal to an end station through a digital broadcast satellite according to a preset period, wherein the wireless signal comprises main station time information, and the digital broadcast satellite transmits the wireless signal through DVB-S2;
the end station receives the wireless signal;
the end station extracts the master station time information from the wireless signal;
and the end station performs clock synchronization with the master station according to the master station time information.
9. An end station, comprising an acquisition module, an extraction module and a synchronization module:
the acquisition module is used for receiving wireless signals forwarded by a master station through a digital broadcast satellite according to a preset period, wherein the wireless signals comprise master station time information, and the digital broadcast satellite is transmitted by adopting DVB-S2;
the extraction module is used for extracting the master station time information from the wireless signals;
and the synchronization module is used for carrying out clock synchronization with the master station according to the master station time information.
10. The end station of claim 9, wherein the master station time information comprises:
the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite;
or the like, or, alternatively,
the master station time information includes a transmission time and a transmission delay time at which the master station transmits the radio signal to the digital broadcast satellite.
11. The end station of claim 10, wherein when the master station time information includes a transmission time of the master station to transmit the radio signal to the digital broadcast satellite; the extracting module is further configured to extract the master station time information from the wireless signal, including: the transmission time of the wireless signal transmitted by the master station to the digital broadcast satellite; the synchronization module is further used for acquiring transmission delay time; adding the sending time and the transmission delay time to obtain a sum as a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
12. The end station of claim 10, wherein when the master station time information includes a transmission time and a transmission delay time for the master station to transmit the radio signal to the digital broadcast satellite; the extracting module is further configured to extract the master station time information from the wireless signal, including: the transmission time and the transmission delay time of the wireless signal transmitted by the main station to the digital broadcast satellite; the synchronization module is further used for adding the sending time and the transmission delay time to form a synchronization standard time; and setting the local time of the end station as the synchronous standard time.
13. The end station of claim 11 or 12, wherein the synchronization module is further configured to obtain a reception time for receiving the wireless signal before the local time of the end station is set as the synchronization standard time; judging whether the receiving time is the same as the synchronous standard time or not; and if the time difference is different, the local time of the end station is set as the synchronization standard time.
14. A system for clock synchronization comprising a master station and an end station:
the main station is used for transmitting a wireless signal forwarded by a digital broadcast satellite to the end station according to a preset period, the wireless signal comprises the time information of the main station, and the digital broadcast satellite is transmitted by adopting DVB-S2;
the end station is used for receiving the wireless signals and extracting the master station time information from the wireless signals; and carrying out clock synchronization with the master station according to the master station time information.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510483653.4A CN106413075B (en) | 2015-08-03 | 2015-08-03 | Method and system for clock synchronization and end station |
| PCT/CN2016/074128 WO2016165476A1 (en) | 2015-08-03 | 2016-02-19 | Clock synchronization method and system, end station and computer storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510483653.4A CN106413075B (en) | 2015-08-03 | 2015-08-03 | Method and system for clock synchronization and end station |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106413075A CN106413075A (en) | 2017-02-15 |
| CN106413075B true CN106413075B (en) | 2020-04-28 |
Family
ID=57126966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510483653.4A Active CN106413075B (en) | 2015-08-03 | 2015-08-03 | Method and system for clock synchronization and end station |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN106413075B (en) |
| WO (1) | WO2016165476A1 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106452642A (en) * | 2015-08-07 | 2017-02-22 | 中兴通讯股份有限公司 | Satellite communication network clock synchronization method and device and base transceiver station |
| CN107040327B (en) * | 2017-06-14 | 2019-04-02 | 深圳市华信天线技术有限公司 | Slave TDMA slot synchronous calibration method and device |
| WO2019010626A1 (en) * | 2017-07-11 | 2019-01-17 | 深圳市柔宇科技有限公司 | Capturing method and terminal |
| WO2019023906A1 (en) * | 2017-07-31 | 2019-02-07 | 深圳市大疆创新科技有限公司 | Synchronization method, device, and system |
| SG11202111519XA (en) * | 2017-10-24 | 2021-11-29 | Skywave Networks Llc | Clock synchronization when switching between broadcast and data transmission modes |
| CN109639339B (en) * | 2018-11-30 | 2021-06-22 | 四川安迪科技实业有限公司 | Bandwidth allocation method suitable for managing large satellite FDMA communication mode |
| CN109995963A (en) * | 2019-05-17 | 2019-07-09 | 张剑飞 | A kind of wireless synchronization time-code method |
| CN110401504B (en) * | 2019-05-21 | 2021-05-28 | 广州天链通信科技有限公司 | Satellite communication system time synchronization method based on TDMA |
| CN110572231B (en) * | 2019-09-09 | 2023-06-06 | 北京百度网讯科技有限公司 | Time synchronization method, device and equipment |
| CN110830411B (en) * | 2019-09-27 | 2020-11-13 | 中国电子科技集团公司第二十九研究所 | Satellite multi-carrier demodulator facing MF-TDMA |
| CN113708876B (en) * | 2021-08-24 | 2023-04-11 | 四川安迪科技实业有限公司 | Forward link time synchronization method of low-orbit satellite TDMA communication system |
| CN113840370B (en) * | 2021-08-31 | 2023-10-13 | 全球能源互联网欧洲研究院 | Clock synchronization method and device for wireless communication interaction and electronic equipment |
| CN114745680A (en) * | 2022-06-10 | 2022-07-12 | 广州世炬网络科技有限公司 | Wireless base station time synchronization method, device, equipment and storage medium |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8780823B1 (en) * | 2009-10-08 | 2014-07-15 | Viasat, Inc. | Event driven grant allocation |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0698195A (en) * | 1992-04-23 | 1994-04-08 | Nec Corp | Digital satellite communication system |
| US8032073B2 (en) * | 2006-05-03 | 2011-10-04 | Stm Networks, Inc. | Satellite communication with multiple active gateways |
| CN101860392B (en) * | 2009-04-07 | 2013-01-16 | 中国移动通信集团公司 | Clock synchronization method and system of satellite communication-based base station |
| JP5260408B2 (en) * | 2009-05-26 | 2013-08-14 | 株式会社日立製作所 | Time synchronization network and communication device |
| CN102213764A (en) * | 2010-04-07 | 2011-10-12 | 中国科学院国家天文台 | Bidirectional satellite navigation and communication positioning method and system |
| CN102545993B (en) * | 2011-12-20 | 2014-04-02 | 中国科学院国家授时中心 | Two-way satellite time transfer method based on carrier phase |
| CN103454911A (en) * | 2013-09-16 | 2013-12-18 | 中国航天科工集团第二研究院二〇三所 | Rough synchronization method for satellite bidirectional time comparison |
| CN103516457A (en) * | 2013-10-28 | 2014-01-15 | 中国航天科工集团第二研究院二〇三所 | High-precision remote time synchronization method |
-
2015
- 2015-08-03 CN CN201510483653.4A patent/CN106413075B/en active Active
-
2016
- 2016-02-19 WO PCT/CN2016/074128 patent/WO2016165476A1/en active Application Filing
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8780823B1 (en) * | 2009-10-08 | 2014-07-15 | Viasat, Inc. | Event driven grant allocation |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106413075A (en) | 2017-02-15 |
| WO2016165476A1 (en) | 2016-10-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106413075B (en) | Method and system for clock synchronization and end station | |
| US8681772B2 (en) | Timing synchronization for networks with radio links | |
| US11483601B2 (en) | Technique for transmitting and receiving system time information in broadcasting system | |
| KR101088599B1 (en) | Method and device for processing a dvb-hdigital video broadcasting-handheld compliant transport stream | |
| US20050265333A1 (en) | Method for enabling efficient multicast transmission in a packet-based network | |
| WO2016078310A1 (en) | Clock synchronization method, device, cascading base station system and storage medium | |
| US20080084838A1 (en) | Apparatus And Method For Satellite Communication Installed In Terrestrial Portable Phone And Similar Ground Terminal | |
| WO2017024782A1 (en) | Clock synchronization method, device, base station and storage medium in a satellite communication network | |
| CN100370805C (en) | Method and system for receiving-end and source-end synchonous of broadcast TV service | |
| CN100536385C (en) | Method for clock synchronization of mobile multimedia broadcast receiving terminal | |
| CN110401504B (en) | Satellite communication system time synchronization method based on TDMA | |
| KR20120042354A (en) | Center district dual mode network synchronization acquisition method and apparatus for satellite communication system | |
| JP6258006B2 (en) | SFN broadcasting system and broadcast TS transmission method using IP line | |
| CN107404754B (en) | Clock synchronization method and system between LTE base stations in rail transit industry | |
| KR20180039023A (en) | Receiving device and data processing method | |
| US9961008B2 (en) | Method and system of handling over routing of communication protocol data between two satellite communication transponders | |
| US20230247242A1 (en) | Content transmission method and content playback method | |
| US11290200B2 (en) | Transmission device, transmission method, reception device, and reception method | |
| WO2016095526A1 (en) | Time service method, apparatus and system, and storage medium | |
| TW201906311A (en) | Demodulation device, processing device, receiving device, and data processing method | |
| CN100571120C (en) | Frame synchornization method in a kind of digital communication | |
| CN112272360B (en) | Current differential protection data synchronization method and system based on 5G network time synchronization | |
| CN105281882A (en) | Method and device for realizing time synchronization | |
| US20100188252A1 (en) | Wireless apparatus | |
| CN101860392A (en) | Clock synchronization method and system of satellite communication-based base station |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |