WO2017071270A1

WO2017071270A1 - Local clock adjustment method, and time service method and device

Info

Publication number: WO2017071270A1
Application number: PCT/CN2016/087310
Authority: WO
Inventors: 王石磊
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-10-30
Filing date: 2016-06-27
Publication date: 2017-05-04
Also published as: CN106656386B; CN106656386A

Abstract

A local clock adjustment method, and a time service method and device. The local clock adjustment method comprises: extracting timing information from a received air interface signal; calculating a frequency offset of a local clock according to the timing information; and adjusting the local clock according to the frequency offset, wherein adjusting the local clock according to the timing information comprises: calculating the frequency offset of the local clock according to a pre-determined manner, and adjusting a frequency of the local clock according to the frequency offset.

Description

Local clock adjustment method, timing method and device

Technical field

This application relates to, but is not limited to, the field of communication technology.

Background technique

In a Long Term Evolution (LTE) system, a terminal device needs to synchronize with a base station before accessing the network to ensure that the base station clocks in the network are unified. For this reason, when the operator is networking, a Global Positioning System (GPS) module is configured for each base station.

According to the characteristics of the LTE system, LTE requires the terminal equipment to have high synchronization accuracy, and avoid inter-symbol interference and interference between terminal devices as much as possible. In the related art, synchronization of the terminal device is completed through a synchronization channel, where the synchronization channel includes a primary synchronization channel and a secondary synchronization channel, and by analyzing the synchronization channel, the terminal device can acquire access cell parameters and timing information, and the theory of the terminal device The accuracy can reach 1Ts, where 1Ts is equal to 1/30720 milliseconds (ms).

The time synchronization accuracy in the related art cannot reach a too high level, and only the phase can be adjusted during the initial synchronization process, and the frequency is not adjusted, so that the terminal device has a frequency deviation and the frequency deviation It will continue to accumulate, resulting in an error in the local clock.

In addition, the base station in the related art LTE system acquires the timing by using the GPS module. Then, when setting up the base station to set up the network, the base station is limited by environmental conditions, for example, for the environment with strict occlusion, when the base station passes the GPS When the module receives the air interface signal sent by the LTE system for time synchronization, the environment is a strict occlusion environment, which may hinder the transmission of the air interface signal, and increase the delay of the GPS module receiving the air interface signal, and even cannot receive, thereby causing the The clock of the site has a large error, and the required timing accuracy is not achieved, thereby affecting the surrounding network performance and reducing the user experience.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

The present invention provides a local clock adjustment method, a timing method and a device to solve the technical problem that the terminal device in the related art has a large error in the way of synchronizing time from the base station, and cannot achieve the precision required for timing.

A local clock adjustment method includes:

Receiving an air interface signal sent by the base station;

Obtaining timing information from the air interface signal;

Adjusting the local clock according to the timing information, wherein the adjusting the local clock according to the timing information comprises: calculating a frequency offset of the local clock according to a predetermined manner, and adjusting a local clock according to the frequency offset Frequency of.

Optionally, in an embodiment of the present invention, the calculating a frequency offset of the local clock according to a predetermined manner includes:

Calculating time domain correlation values based on orthogonal frequency division multiple access symbol sample data of one or more complete cyclic prefixes;

Performing an arctangent calculation according to the time domain correlation value to obtain a frequency offset of the local clock.

Optionally, in an embodiment of the present invention, the calculating the time domain correlation value according to the orthogonal frequency division multiple access symbol sampling data of a complete cyclic prefix, including:

Calculating the corresponding time domain correlation value according to the orthogonal frequency division multiple access symbol sampling data of a complete one-cycle prefix of the formula;

Formula one:

Where c is the time domain correlation value; N _CP is the number of sampling points of the cyclic prefix; n is the sampling index of the orthogonal frequency division multiple access symbol; a, b are constants, and are any integers in the 1, 2, 3...N _CP N is the number of sampling points of orthogonal frequency division multiple access; S(n)* is the conjugate of the sampling data of the orthogonal frequency division multiple access sampling signal; S(n+N) is an orthogonal frequency division multiple access sampling data Data of (n+N) sample points;

Calculating time domain correlation according to orthogonal frequency division multiple access symbol sampling data of multiple complete cyclic prefixes Values, including:

Calculating corresponding time domain correlation values according to a pair of orthogonal frequency division multiple access symbol sample data of each of the complete cyclic prefixes; and averaging all obtained time domain correlation values.

Optionally, in an embodiment of the present invention, performing an arctangent calculation according to the time domain correlation value to obtain a frequency offset of the local clock, including:

Performing an arctangent calculation on the time domain correlation value according to formula 2, obtaining a frequency offset Δf of the local clock;

Formula 2:

Where Ts is the sampling interval and Ts=1/30720000 seconds.

Optionally, in an embodiment of the present invention, the adjusting the local clock according to the timing information further includes:

Calculating an error of the crystal oscillator of the terminal device according to the calculated frequency offset, and performing compensation adjustment on the crystal oscillator of the local clock according to the calculated error.

Optionally, in an embodiment of the present invention, after the local clock is adjusted according to the timing information, the method further includes:

Periodically adjusting the local clock; wherein the periodically adjusting the local clock includes:

Calculating a time offset accumulated by the local clock in a current time period;

Calculating a time offset compensation amount of the local clock in the current time period according to the time offset;

Calculating a time correction amount of the local clock in the current time period according to the time offset compensation amount and a duration in the current time period;

The local clock is compensated and adjusted according to the time correction amount.

Optionally, in an embodiment of the present invention, the calculating a time offset accumulated by the local clock in a current time period includes:

Calculating a time offset of each subframe in the current time period;

The time offset average value is obtained according to the time offset of each subframe in the current time period or the time offset of the partial subframe.

Optionally, in an embodiment of the present invention, the calculating a time offset compensation amount of the local clock in the current time period according to the time offset includes:

Calculating the time offset compensation amount ΔTa of the local clock in the current time period according to the time offset average value:

ΔTa=averageTimeOffset-TimeOffsetLast;

The averageTimeOffset is an average value of the time offset of the local clock in the current time period, and TimeOffsetLast is a time offset of the local clock when the previous time period is adjusted.

Optionally, in an embodiment of the present invention, the calculating the time correction amount of the local clock according to the time offset compensation amount and the duration in the current time period, including:

Calculating the time correction amount of the local clock according to formula 3;

Formula 3:

Where T is the duration of the current time period; Error is the error time correction of the local clock; ppb is the nanogram 1 ppb = 10 ^-9 .

A timing method comprising:

The terminal device adjusts the local clock according to the local clock adjustment method described in any of the above;

The terminal device performs timing for other terminal devices according to the adjusted local clock.

A local clock adjustment device includes:

The receiving module is configured to: receive the air interface signal sent by the base station;

An acquiring module, configured to: obtain timing information from the air interface signal received by the receiving module;

The adjusting module is configured to: adjust the local clock according to the timing information acquired by the acquiring module, where the adjusting module is configured to: calculate a frequency offset of the local clock according to a predetermined manner, and according to the frequency offset The shift adjusts the frequency of the local clock.

Optionally, in an embodiment of the present invention, the adjusting module includes:

a time domain correlation value calculation unit, configured to: calculate a time domain correlation value according to orthogonal frequency division multiple access symbol sample data of one or more complete cyclic prefixes;

The frequency offset calculation unit is configured to perform an arctangent calculation according to the time domain correlation value calculated by the time domain correlation value calculation unit, to obtain a frequency offset of the local clock;

The frequency adjustment unit is configured to adjust the frequency of the local clock according to the frequency offset of the local clock calculated by the frequency offset calculation unit.

Optionally, in an embodiment of the present invention, the adjusting module further includes:

a time offset calculation unit configured to: calculate a time offset accumulated by the local clock in a current time period;

The time offset compensation amount calculation unit is configured to: calculate a time offset compensation amount of the local clock in the current time period according to the time offset calculated by the time offset calculation unit;

The time correction amount calculation unit is configured to: calculate the local clock in the current time period according to the duration in the current time period and the time offset compensation amount calculated by the time offset compensation amount calculation unit Time correction amount;

The time adjustment unit is configured to: perform compensation adjustment on the local clock according to the time correction amount calculated by the time correction amount calculation unit.

A timing device, comprising: the local clock adjustment device according to any one of the above, and a timing module;

The local clock adjustment device is configured to: receive an air interface signal sent by the base station, obtain timing information from the air interface signal, and adjust a local clock according to the timing information, where the local clock is adjusted according to the timing information, including: Calculating a frequency offset of the local clock in a predetermined manner, and adjusting a frequency of the local clock according to the frequency offset;

The timing module is configured to: time the other terminal devices according to the clock adjusted by the local clock adjustment device.

The local clock adjustment method, the timing method and the device provided by the embodiment of the present invention, the terminal device obtains the timing information from the air interface signal by receiving the air interface signal sent by the base station, according to the The timing information is used to calculate the frequency offset of the local clock, and the local clock is adjusted according to the calculated frequency offset. Compared with the method of adjusting the phase in the related art, the localized by the method provided by the embodiment of the present invention is adjusted. The clock accuracy is higher. The local time adjustment device is set on the base station or the terminal device by using the technical solution provided by the embodiment of the present invention, so that the terminal device can directly receive the air interface signal of the base station, obtain the timing information therein, and calculate the timing information. Adjusting the local clock does not require the GPS module or other hardware to be configured on the base station or the terminal device to receive the air interface signal of the base station, which not only reduces the error of the timing synchronization, but also achieves the precision required for timing, and simplifies the hardware structure of the base station or the terminal device. And reduce costs.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

FIG. 1 is a schematic structural diagram of a local clock adjustment apparatus according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of another local clock adjusting apparatus according to an embodiment of the present invention;

3 is a schematic structural diagram of a timing device according to an embodiment of the present invention;

FIG. 4 is a flowchart of a method for adjusting a local clock according to an embodiment of the present invention;

FIG. 5 is a flowchart of another local clock adjustment method according to an embodiment of the present invention;

FIG. 6 is a flowchart of a timing method according to an embodiment of the present invention.

Embodiments of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments herein may be arbitrarily combined with each other.

The steps illustrated in the flowchart of the figures may be executed in a computer system in accordance with a set of computer executable instructions. Also, although logical sequences are shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than the ones described herein.

FIG. 1 is a schematic structural diagram of a local clock adjustment apparatus according to an embodiment of the present invention. As shown in FIG. 1 , the local clock adjustment apparatus provided in this embodiment may include: a receiving module 11 , an obtaining module 12 , and an adjusting module 13 .

The receiving module 11 is configured to: receive an air interface signal sent by the base station;

The obtaining module 12 is configured to: obtain timing information from the air interface signal received by the receiving module 11;

The adjusting module 13 is configured to: adjust the local clock according to the timing information acquired by the obtaining module 12, and the manner in which the adjusting module 13 adjusts the local clock in the embodiment may include: calculating a frequency offset of the local clock according to a predetermined manner, and calculating according to a predetermined manner The frequency offset is adjusted to adjust the frequency of the local clock.

In this embodiment, the receiving module 11 is responsible for receiving the air interface signal sent by the base station of the LTE system, and the air interface signal may be an air interface signal sent by the sending unit specified by the LTE system, or may be sent by other modules. Other air interface signals with timing information. In this embodiment, the receiving module 11 can receive the air interface signal according to the needs of the base station, and the receiver module 11 can be configured to receive the radio signal of the air interface, and can also be designed as a receiving device shared with the service radio frequency circuit of the base station, thereby reducing the hardware of the base station. The design cost of the receiving module 11 in this embodiment does not need to be configured with a GPS module, and can also receive signals for timing synchronization, which simplifies the hardware structure of the base station or the terminal device, thereby reducing the cost and enhancing the user experience. After receiving the air interface signal, the receiving module 11 in the embodiment outputs the air interface signal to the acquiring module 12 for extracting timing information, and then the adjusting module 13 calculates a clock correction for adjusting the local clock according to the timing information acquired by the obtaining module 12. the amount.

Optionally, the adjustment module 13 in this example may include, for example, a digital signal processing (DSP) chip and a digital to analog converter (DAC) chip. 13 not only can adjust the frequency offset of the local clock, but also adjust the phase of the local clock.

Optionally, as shown in FIG. 2, it is a schematic structural diagram of another local clock adjustment apparatus according to an embodiment of the present invention. In the local clock adjustment apparatus provided in this embodiment, the adjustment module 13 may include a time domain correlation value calculation module 131, a frequency offset calculation unit 132, and a frequency adjustment unit 133.

The time domain correlation value calculation unit 131 is configured to: calculate a time domain correlation value according to the orthogonal frequency division multiple access symbol sample data of one or more complete cyclic prefixes;

The frequency offset calculation unit 132 is configured to perform an arctangent calculation according to the time domain correlation value calculated by the time domain correlation value calculation unit 131 to obtain a frequency offset of the local clock;

The frequency adjustment unit 133 is configured to: calculate the obtained version according to the frequency offset calculation unit 132. The frequency offset of the ground clock adjusts the frequency of the local clock.

Optionally, in an implementation manner of this embodiment, when the time domain correlation value calculation unit 131 calculates a time domain correlation value for the orthogonal frequency division multiple access symbol sample data of a complete cyclic prefix, the time domain correlation value calculation is performed. Unit 131 calculates the time domain correlation value by formula one:

Formula one:

Where c is the time domain correlation value; N _CP is the number of sampling points of the cyclic prefix; n is the sampling index of the orthogonal frequency division multiple access symbol; a, b are constants, and are any integers in the 1, 2, 3...N _CP N is the number of sampling points of orthogonal frequency division multiple access; S(n) is the conjugate of the sampling data of the orthogonal frequency division multiple access sampling signal; S(n+N) is an orthogonal frequency division multiple access sampling data (n+N) data of sampling points;

Optionally, in another implementation manner of this embodiment, when the time domain correlation value calculation unit 131 calculates a time domain correlation value for the orthogonal frequency division multiple access symbol sample data of the multiple complete cyclic prefix, the time domain correlation is performed. The value calculation unit 131 first calculates a corresponding time domain correlation value c for each pair of orthogonal frequency division multiple access symbol sample data of each complete cyclic prefix according to the above formula; and then averages each of the obtained time domain correlation values.

Optionally, the frequency offset calculation unit 132 in the embodiment performs an arctangent calculation on the time domain correlation value c calculated by the time domain correlation value calculation unit 131, and the implementation manner of obtaining the frequency offset of the local clock may be :

The frequency offset calculation unit 132 performs arctangent calculation on the time domain correlation value according to the following formula 2, and obtains the frequency offset Δf of the local clock;

Formula 2:

Where Ts is the sampling interval and Ts=1/30720000 seconds (s).

Optionally, as shown in FIG. 2, in the local clock adjustment apparatus provided in this embodiment, the adjustment module 13 further includes:

The time offset calculation unit 134 is configured to: calculate a time offset accumulated by the local clock in the current time period;

The time offset compensation amount calculation unit 135 is configured to: calculate a time offset compensation amount of the local clock in the current time period according to the time offset calculated by the time offset calculation unit 134;

The time correction amount calculation unit 136 is configured to: calculate a time offset compensation amount calculated by the duration and time offset compensation amount calculation unit 135 in the current time period, and calculate a time correction amount of the local clock in the current time period;

The time adjustment unit 137 is configured to perform compensation adjustment on the local clock according to the time correction amount calculated by the time correction amount calculation unit 136.

In an actual application, the adjustment module 13 in this embodiment is further configured to: after completing the adjustment of the local clock, initiate random access, so that the terminal device is connected to the base station, and acquires the terminal device and the base station calculated by the base station. The amount of time offset between the delays due to the distance is adjusted, and the local clock is further adjusted according to the time offset adjustment amount.

FIG. 3 is a schematic diagram of a timing device according to an embodiment of the present invention. The timing device provided in this embodiment may include: a local clock adjustment device 21 and a timing module 22.

The local clock adjustment device 21 in this embodiment may be the local clock adjustment device provided in any of the embodiments shown in FIG. 1 and FIG. 2, and the local clock adjustment device 21 is configured to: receive the air interface signal sent by the base station, and Obtaining the timing information according to the timing information, and adjusting the local clock according to the timing information, wherein the local clock is adjusted according to the timing information, and the frequency offset of the local clock is calculated according to a predetermined manner, and the frequency offset is calculated according to the frequency Adjust the frequency of the local clock.

The timing module 22 is configured to: time the other terminal devices according to the clock adjusted by the local clock adjustment device 21.

The timing device provided in this embodiment may be placed in a terminal device, and the terminal device can directly receive the air interface signal sent by the LTE system base station by setting the local clock adjustment device 21, and obtain timing information from the air interface signal, according to the timing. The information calculates a clock correction amount for adjusting the phase, the frequency offset, and the time offset of the local clock, so that the local clock is relatively locked with the base station clock of the LTE system, and the terminal device and the base station are synchronized with the clock, except that the terminal device exists. In addition to the distance delay time offset between the base stations, there is no case that the local clock still has a time offset, thereby improving the accuracy of the synchronous timing of the terminal device.

Optionally, the local time adjusted by the local clock adjustment device 21 by the timing module 22 The clock is used to grant time to other terminal devices. The other devices here may be subordinate devices attached to the terminal device, or may be terminal devices at the same level as the terminal device.

The local clock adjusting device and the timing device provided by the embodiment of the present invention, the terminal device obtains the timing information from the air interface signal by receiving the air interface signal sent by the base station, calculates the frequency offset of the local clock according to the timing information, and calculates the frequency offset according to the timing information. The frequency offset is adjusted to the local clock. Compared with the method of adjusting the phase in the related art, the local clock adjusted by the method provided by the embodiment of the present invention has higher precision; the frequency adjustment of the local clock is performed. On the basis of the present invention, the time offset in a time period can be calculated according to the adjusted local clock, and the periodic adjustment is performed, thereby reducing the time error of the local clock and improving the precision of the synchronous timing. In addition, the local time adjustment device is set on the base station or the terminal device by using the technical solution provided by the embodiment of the present invention, so that the terminal device can directly receive the air interface signal of the base station, obtain the timing information therein, and calculate and adjust the timing information. The local clock does not need to configure the GPS module or other hardware on the base station or the terminal device to receive the air interface signal of the base station, which not only reduces the error of the timing synchronization, achieves the precision required for timing, but also simplifies the hardware structure of the base station or the terminal device. Reduced costs.

FIG. 4 is a flowchart of a local clock adjustment method according to an embodiment of the present invention. The local clock adjustment method provided in this embodiment may include the following steps, that is, S310 to S330:

S310. Receive an air interface signal sent by the base station.

S320. Obtain timing information from the air interface signal.

S330. Adjust a local clock according to the timing information. The local clock is adjusted according to the timing information, including: calculating a frequency offset of the local clock according to a predetermined manner, and adjusting a frequency of the local clock according to the frequency offset.

In S310 of the embodiment, the air interface signal may be an air interface signal that is sent by the sending unit specified by the LTE system, or may be an air interface signal that is sent by other modules and includes timing information; The other modules are also sent by the designated sending unit, and the base station or the terminal device can be received without setting the GPS module. After receiving the air interface signal, executing S320, extracting timing information, and then calculating a correction amount for adjusting the local clock according to the timing information, that is, executing S330.

Optionally, in S330 of this embodiment, the implementation of calculating the frequency offset according to the timing information may include: first, acquiring the orthogonal frequency division multiple access symbol sampling data of a complete cyclic prefix, which may be obtained by:

S(n)=S(n+N), n=1, 2...N _CP , N=2048;

When there is a frequency offset, assuming a frequency offset of Δf, then:

Assuming that the phase range produced by Δf is at (-π, π), then:

Where Ts is the sampling interval (1/30720000s), N=2048.

Then, the time domain correlation value c is calculated according to the Orthogonal Frequency Division Multiple Access symbol sample data of a complete cyclic prefix obtained above:

Formula one:

Therefore, the frequency offset Δf of the local clock is calculated according to the time domain correlation value, and is calculated by Formula 2:

Formula 2:

Optionally, in this embodiment, when there are multiple orthogonal cyclic prefix orthogonal frequency division multiple access symbol sampling data, the implementation manner of calculating the time domain correlation value c may be: formulating the time domain correlation value according to the above formula Calculating a corresponding time domain correlation value c by using a pair of orthogonal frequency division multiple access symbol sample data of each complete cyclic prefix; and averaging all obtained time domain correlation values to obtain an average value of time domain correlation values; The average of the domain correlation values calculates the frequency offset Δf of the local clock.

In the method provided in this embodiment, the frequency offset Δf of the local clock is calculated by calculating the time domain correlation value c by calculating the orthogonal frequency division multiple access symbol sampling data of the multiple complete cyclic prefix, and calculating multiple In the complete loop, it is also necessary to calculate the time domain correlation value of each complete loop, and then add up the number of complete loops, and the method of averaging after the accumulation will reduce the calculation error, and the single calculation will appear. Large random rate with high error and low accuracy.

Optionally, as shown in FIG. 5, it is a flowchart of another local clock adjustment method according to an embodiment of the present invention. On the basis of the process of the embodiment shown in FIG. 4, the method provided in this embodiment may further include:

S340, calculating an error of the crystal oscillator of the terminal device according to the calculated frequency offset, and performing compensation adjustment on the crystal oscillator of the local clock according to the calculated error; in actual application, calculating the error of the crystal oscillator of the terminal device can be calculated by the following formula.

Where Error2 is the error of the local crystal oscillator; f _carry is the carrier frequency of the signal.

Optionally, in an implementation manner of this embodiment, after performing S320, and before S330, the method may further include:

S321: Adjust the phase of the local clock according to the acquired timing information, and adjust the phase of the local clock to include the half frame synchronization and the frame synchronization; the half frame synchronization is to collect the air interface signal frame once every 5 milliseconds to obtain the time. The air interface signal clock, frame synchronization is to collect the air interface signal frame once every 10 milliseconds to obtain the air interface signal clock at that moment, and compare the phase with the local clock after each acquisition.

Optionally, in an implementation manner of this embodiment, after performing S330, the method may further include:

S350: Perform periodic adjustment on the local clock. In an actual application, the periodic adjustment manner may include: calculating a time offset accumulated by the local clock in the current time period, and calculating a current time period according to the time offset. The time offset compensation amount of the local clock is calculated according to the time offset compensation amount and the duration in the current time period, and the local clock time correction amount is calculated, and the local clock is compensated and adjusted according to the time correction amount.

Optionally, in S350 of the embodiment, in the process of calculating the time offset accumulated in the current time period, the method further includes: calculating a time offset of each subframe in the current time period, and then calculating according to the calculation The time offset of each sub-frame is averaged to obtain a time offset average.

Optionally, the implementation manner of calculating the time offset of each subframe or multiple subframes in this embodiment may include:

Take the broadband correlation values and accumulate them, and accumulate all the transceiver channels corresponding to each time offset. The bandwidth correlation value is a pilot signal correlation value, and the calculation formula is:

Where Sum is the accumulated value of the bandwidth correlation value; S(n) is the sampling data of the orthogonal frequency division multiple access sampling signal; S(n+N) is (n+N) of one orthogonal frequency division multiple access sampling data The conjugate of the data of the sampling point; N _rs is the number of sampling points of the pilot signal, which is determined by the system, and the maximum value is 200;

Calculate the phase (Phase) of the complex number of the local clock based on the calculated bandwidth accumulated value, which can be:

Phase=angle(sum);

Calculating the time offset TimeOffset according to the calculated phase of the complex number can be:

Where FFTsize is the number of fast Fourier transform points;

Then, the time offset average value (averageTimeOffset) is obtained according to the time offset of each subframe in the current time period or the time offset of the partial subframe.

In practical applications, if a plurality of sub-frames are used to calculate the average value, the accuracy of the calculated time offset can be improved, and the calculation error due to random factors can be reduced.

Optionally, the implementation manner of calculating the time offset compensation amount of the local clock in the current time period according to the time offset in the embodiment may include: calculating the time of the local clock in the current time period according to the time offset average value (averageTimeOffset) The offset compensation amount ΔTa can be:

ΔTa=averageTimeOffset-TimeOffsetLast;

Among them, TimeOffsetLast is the time offset of the local clock when it is adjusted in the previous time period.

For example, when the synchronization period of the LTE system is 20 seconds, calculate the time offset of each subframe, and then select the time offset average value AverageTimeOffset in the last several of the current time periods; optionally, Select the time offset average value TO1 in the time offset of the last 64 subframes, assuming that the time offset of the local clock when the previous time period is adjusted is TL1, then the offset compensation in the period of 20 seconds The amount is ΔTa=TO1-TL1.

Optionally, the terminal device in this embodiment calculates the time correction amount of the local clock according to the time offset compensation amount and the duration in the current time period, including: calculating the local clock according to the following formula 3. Time correction:

Formula 3:

Where T is the duration of the current time period; Error is the time correction of the local clock; ppb is the nanogram of 1 ppb = 10 ^-9 .

In this embodiment, the terminal device performs a local clock adjustment method, and the terminal device calculates the time correction amount of the local clock according to the time offset compensation amount and the duration of the time period, and performs local clock adjustment according to the time correction amount. The method may further include: determining whether the time offset change amount in a time period is greater than T1, and if yes, calculating the local clock error Error again, the calculation manner may be:

Where ΔTa1 is the time offset change amount; Time is the time length at which the time offset change amount is generated.

In this embodiment, since the time compensation amount of the local clock is calculated by calculating the time offset, the local clock may still have a certain time deviation, and there is a certain time offset, therefore, In this case, the terminal device can also determine whether there is a residual time offset after the local clock adjusted according to the calculated time offset is stable, and if so, introduce a clock frequency offset from the residual time offset in the opposite direction to the local clock. Make adjustments.

In practical applications, the criterion for determining whether the local clock is stable is that the time offset variation in the period in which the terminal device and the base station perform clock synchronization is less than mTs, indicating that the local clock is stable; in addition, when the synchronization period is 20 Seconds, and when m=3, the time offset of the local clock is less than 3Ts within 20 seconds, then it is judged whether there is a residual time offset after the local clock is stable, and if so, the introduction and residual time offset are reversed. The clock frequency offset of the direction adjusts the local clock.

Optionally, the method provided in this embodiment may further include: determining whether the time offset change amount in the period is performed after performing the periodic adjustment according to the time correction amount in order to ensure that the synchronization accuracy of the terminal device and the base station is higher. If it is greater than the preset value or whether there is a residual time offset, if it is greater than or there is a residual offset, continue to calculate the compensation adjustment or introduce the clock frequency offset adjustment in the reverse direction.

Optionally, in the method provided in this embodiment, the local clock adjustment method of the terminal device is completed. After the time offset of the local clock is compensated, the method further includes: transmitting a random access signal, establishing a connection with the base station, acquiring a time offset adjustment amount sent by the base station, and compensating the local clock according to the time offset adjustment amount.

The time offset adjustment amount in the embodiment and the optional implementation manner of the present invention refers to a time offset adjustment amount of a delay caused by a distance between a terminal device and a base station, and the time offset is through the terminal. When the device and the base station initiate random access, the base station calculates and returns the calculated time offset adjustment amount to the terminal device, and then the terminal device adjusts itself, and finally realizes complete timing synchronization of the terminal device and the base station clock.

FIG. 6 is a flowchart of still another method for timing a terminal device according to an embodiment of the present invention. The method provided in this embodiment includes the following steps, that is, steps 410 to 440:

S410. Receive an air interface signal sent by the base station.

S420: Obtain timing information from the air interface signal.

S430, adjusting the local clock according to the timing information, wherein adjusting the local clock according to the timing information comprises: calculating a frequency offset of the local clock according to a predetermined manner, and adjusting a frequency of the local clock according to the frequency offset.

In this embodiment, the implementations of S410 to S430 may be the same as those of S310 to S330 in the example shown in FIG. 4 and FIG. 5, and therefore are not described herein again.

S440: Perform timing on other terminal devices according to the adjusted local clock.

The local clock adjusted in this embodiment refers to the local clock adjusted by the terminal device through the foregoing steps S410 to S430. In this embodiment, before the other terminal devices are timed, the local clock adjustment method in any of the embodiments shown in FIG. 4 and FIG. 5 is first performed, thereby eliminating the frequency offset and time offset of the local clock itself. shift.

Optionally, after the time offset of the local clock is removed by the local clock adjustment method in the embodiment shown in FIG. 4 and FIG. 5, the terminal device also needs to initiate random access, where the random access is the terminal device The base station establishes communication, acquires the random access corresponding signaling sent by the base station, and obtains a time offset Ta from the signaling, where the time offset Ta represents twice the delay introduced by the path difference. Therefore, the clock is further compensated by Ta/2, so that the local clock and the base station clock error are guaranteed within a certain range of errors.

In the step S440 of the embodiment, the timing of the other terminal devices is required to be completed by using a preset time-sending protocol. Optionally, the time-sending protocol may be a 1588 timing protocol, but is not limited to the timing protocol.

The local clock adjustment method, the timing method and the device provided by the embodiments of the invention can ensure the accurate synchronization between the terminal device and the base station and reduce the hardware cost of the terminal device in the environment with high sealing performance, and also reduce the hardware cost of the terminal device. The difficulty for the operator to perform the network deployment of the base station does not need to consider the problem of receiving the signal due to environmental factors. Moreover, the time synchronization device for realizing the clock synchronization by the local clock adjustment method and the timing method provided by the present invention reduces the difficulty of maintaining the base station, and does not need to configure the GPS module on the terminal device, and the timing device can also implement the terminal. The device is synchronized with the timing of the base station.

One of ordinary skill in the art will appreciate that all or a portion of the steps of the above-described embodiments can be implemented using a computer program flow, which can be stored in a computer readable storage medium on a corresponding hardware platform (according to The system, device, device, device, etc. are executed, and when executed, include one or a combination of the steps of the method embodiments.

Alternatively, all or part of the steps of the above embodiments may also be implemented by using an integrated circuit. These steps may be separately fabricated into individual integrated circuit modules, or multiple modules or steps may be fabricated into a single integrated circuit module. achieve.

The devices/function modules/functional units in the above embodiments may be implemented by a general-purpose computing device, which may be centralized on a single computing device or distributed over a network of multiple computing devices.

When the device/function module/functional unit in the above embodiment is implemented in the form of a software function module and sold or used as a stand-alone product, it can be stored in a computer readable storage medium. The above mentioned computer readable storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

Industrial applicability

In the embodiment of the present invention, the terminal device obtains the timing information from the air interface signal by receiving the air interface signal sent by the base station, calculates the frequency offset of the local clock according to the timing information, and calculates the local frequency clock according to the calculated frequency offset. Make adjustments; compared to the only relevant phase in the related art The accuracy of the local clock adjusted by the method provided by the embodiment of the present invention is higher. On the basis of the frequency adjustment of the local clock, the embodiment of the present invention can also calculate the time period according to the adjusted local clock. The time offset is adjusted periodically, which reduces the time error of the local clock and improves the accuracy of synchronous timing. In addition, the local time adjustment device is set on the base station or the terminal device by using the technical solution provided by the embodiment of the present invention, so that the terminal device can directly receive the air interface signal of the base station, obtain the timing information therein, and calculate and adjust the timing information. The local clock does not need to configure the GPS module or other hardware on the base station or the terminal device to receive the air interface signal of the base station, which not only reduces the error of the timing synchronization, achieves the precision required for timing, but also simplifies the hardware structure of the base station or the terminal device. Reduced costs.

Claims

A local clock adjustment method includes:

Receiving an air interface signal sent by the base station;

Obtaining timing information from the air interface signal;

Adjusting the local clock according to the timing information, wherein the adjusting the local clock according to the timing information comprises: calculating a frequency offset of the local clock according to a predetermined manner, and adjusting the frequency according to the frequency offset The frequency of the local clock.
The local clock adjustment method according to claim 1, wherein the calculating the frequency offset of the local clock according to a predetermined manner comprises:

Calculating time domain correlation values based on orthogonal frequency division multiple access symbol sample data of one or more complete cyclic prefixes;

Performing an arctangent calculation according to the time domain correlation value to obtain a frequency offset of the local clock.
The local clock adjustment method according to claim 2, wherein the calculating the time domain correlation value according to the orthogonal frequency division multiple access symbol sampling data of one complete cyclic prefix comprises:

Calculating the corresponding time domain correlation value according to the orthogonal frequency division multiple access symbol sampling data of a complete one-cycle prefix of the formula;

Where c is the time domain correlation value; N CP is the number of sampling points of the cyclic prefix; n is the sampling index of the orthogonal frequency division multiple access symbol; a, b are constants, and are any integers in the 1, 2, 3...N CP N is the number of sampling points of orthogonal frequency division multiple access; S(n)* is the conjugate of the sampling data of the orthogonal frequency division multiple access sampling signal; S(n+N) is an orthogonal frequency division multiple access sampling data Data of (n+N) sample points;

The calculating the time domain correlation value according to the orthogonal frequency division multiple access symbol sampling data of the multiple complete cyclic prefixes, including:

Calculating corresponding time domain correlation values according to a pair of orthogonal frequency division multiple access symbol sample data of each of the complete cyclic prefixes; and averaging all obtained time domain correlation values.
The local clock adjustment method according to claim 3, wherein the performing an arctangent calculation according to the time domain correlation value to obtain a frequency offset of the local clock includes:

Performing an arctangent calculation on the time domain correlation value according to formula 2, obtaining a frequency offset Δf of the local clock;

Where Ts is the sampling interval and Ts=1/30720000 seconds.
The local clock adjustment method according to claim 1, wherein the adjusting the local clock according to the timing information further includes:

Calculating an error of the crystal oscillator of the terminal device according to the calculated frequency offset, and performing compensation adjustment on the crystal oscillator of the local clock according to the calculated error.
The local clock adjustment method according to any one of claims 1 to 5, wherein after the adjusting the local clock according to the timing information, the method further includes:

Periodically adjusting the local clock; wherein the periodically adjusting the local clock includes:

Calculating a time offset accumulated by the local clock in a current time period;

Calculating a time offset compensation amount of the local clock in the current time period according to the time offset;

Calculating a time correction amount of the local clock in the current time period according to the time offset compensation amount and a duration in the current time period;

The local clock is compensated and adjusted according to the time correction amount.
The local clock adjustment method according to claim 6, wherein the calculating the time offset accumulated by the local clock in the current time period comprises:

Calculating a time offset of each subframe in the current time period;

The time offset average value is obtained according to the time offset of each subframe in the current time period or the time offset of the partial subframe.
The local clock adjustment method according to claim 7, wherein said according to said time The offset calculates a time offset compensation amount of the local clock in the current time period, including:

Calculating the time offset compensation amount ΔTa of the local clock in the current time period according to the time offset average value:

ΔTa=averageTimeOffset-TimeOffsetLast;

The averageTimeOffset is an average value of the time offset of the local clock in the current time period, and TimeOffsetLast is a time offset of the local clock when the previous time period is adjusted.
The local clock adjustment method according to claim 8, wherein the calculating the time correction amount of the local clock according to the time offset compensation amount and the duration in the current time period comprises:

Calculating the time correction amount of the local clock according to formula 3;

Where T is the duration of the current time period; Error is the time correction amount of the local clock; ppb is the nanogram level of 1 ppb=10 -9 .
A terminal device timing method includes:

The terminal device adjusts the local clock according to the local clock adjustment method according to any one of claims 1 to 9;

The terminal device performs timing for other terminal devices according to the adjusted local clock.
A local clock adjustment device includes:

The receiving module is configured to: receive the air interface signal sent by the base station;

An acquiring module, configured to: obtain timing information from the air interface signal received by the receiving module;

The adjusting module is configured to: adjust the local clock according to the timing information acquired by the acquiring module, where the adjusting module is configured to: calculate a frequency offset of the local clock according to a predetermined manner, and according to the frequency offset The shift adjusts the frequency of the local clock.
The local clock adjusting device according to claim 11, wherein said adjustment module package include:

a time domain correlation value calculation unit, configured to: calculate a time domain correlation value according to orthogonal frequency division multiple access symbol sample data of one or more complete cyclic prefixes;

The frequency offset calculation unit is configured to perform an arctangent calculation according to the time domain correlation value calculated by the time domain correlation value calculation unit, to obtain a frequency offset of the local clock;

The frequency adjustment unit is configured to adjust the frequency of the local clock according to the frequency offset of the local clock calculated by the frequency offset calculation unit.
The local clock adjustment apparatus according to claim 11 or 12, wherein the adjustment module further comprises:

a time offset calculation unit configured to: calculate a time offset accumulated by the local clock in a current time period;

The time offset compensation amount calculation unit is configured to: calculate a time offset compensation amount of the local clock in the current time period according to the time offset calculated by the time offset calculation unit;

The time correction amount calculation unit is configured to: calculate the local clock in the current time period according to the duration in the current time period and the time offset compensation amount calculated by the time offset compensation amount calculation unit Time correction amount;

The time adjustment unit is configured to: perform compensation adjustment on the local clock according to the time correction amount calculated by the time correction amount calculation unit.
A timing device comprising: the local clock adjustment device according to any one of claims 11 to 13, and a timing module;

The local clock adjustment device is configured to: receive an air interface signal sent by the base station, obtain timing information from the air interface signal, and adjust a local clock according to the timing information, where the local clock is adjusted according to the timing information, including: Calculating a frequency offset of the local clock in a predetermined manner, and adjusting a frequency of the local clock according to the frequency offset;

The timing module is configured to: time the other terminal devices according to the clock adjusted by the local clock adjustment device.