Air interface timing method, terminal and system

Abstract

The embodiment of the present invention discloses an air interface timing method, terminal and system. In this solution, the terminal recovers the wireless frame header of the base station according to the TA sent by the base station, and maintains the frame number corresponding to the wireless frame header; the terminal determines the initial second pulse number signal according to the SIB9 broadcast by the base station, and the terminal maintains the subsequent multiple second pulse number signals locally based on the initial second pulse number signal, and uses the valid second pulse number signal and the local time to perform timing synchronization. Since the absolute time information used to determine the initial second pulse number signal carried in the SIB9 is obtained by the base station through PTP or GNSS, and the initial second pulse number signal and the valid second pulse number signal determined by the subsequent multiple second pulse number signals maintained by the initial second pulse number signal are used for timing synchronization, it can ensure that the synchronization accuracy is at the nanosecond level, reduce the impact of the air interface channel quality on the timing solution, and improve the stability and synchronization accuracy of air interface timing in universal ubiquitous Internet of Things scenarios.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of communication technology, and in particular to an air interface timing method, terminal, and system. Background Art

[0002] With the continuous development of the fifth generation wireless systems (5G), its application in vertical industries is becoming more and more extensive. Its low latency, high bandwidth, high transmission rate, massive access, precise positioning and timing functions are increasingly valued, especially in the ubiquitous Internet of Things.

[0003] Currently, most systems provide synchronization sources and perform wireless timing through the air interface. Specifically, this is done by adding a system broadcast message System Information Block (SIB) or sending Time of Day (TOD) information over the air interface through Radio Resource Control (RRC) signaling. The timing accuracy can reach microseconds.

[0004] However, in the face of current business needs, the current air interface timing solution still has defects such as low timing accuracy, the stability of timing is greatly affected by channel quality, and it is not suitable for ubiquitous Internet of Things scenarios that require stable and high-precision timing. Summary of the Invention

[0005] The purpose of one or more embodiments of this specification is to provide an air-interface timing method, terminal, and system that can improve the stability and synchronization accuracy of air-interface timing in universal ubiquitous Internet of Things scenarios.

[0006] To solve the above technical problems, one or more embodiments of this specification are implemented as follows:

[0007] In a first aspect, an air interface timing method is provided, which is applied to a terminal side, and the method includes:

[0008] Recover the radio frame header of the base station according to the timing advance TA issued by the base station, and maintain the frame number corresponding to the radio frame header;

[0009] Obtaining a system information block SIB9 broadcast by a base station, and determining an initial pulse per second signal based on the SIB9 and the frame number, wherein the SIB9 carries absolute time information obtained by the base station through PTP or GNSS;

[0010] locally maintaining a subsequent plurality of pulse-per-second signals based on the initial pulse-per-second signal;

[0011] Timing synchronization is performed using a valid pulse-per-second signal determined based on the plurality of pulse-per-second signals and a local time.

[0012] In a second aspect, a terminal is provided, including:

[0013] A recovery module, configured to recover a radio frame header of the base station according to a timing advance TA sent by the base station, and maintain a frame number corresponding to the radio frame header;

[0014] a determination module, configured to obtain a system information block SIB9 broadcast by the base station and determine an initial pulse per second signal, wherein the SIB9 carries absolute time information obtained by the base station through PTP or GNSS;

[0015] a maintenance module, configured to locally maintain a plurality of subsequent pulse-per-second signals based on the initial pulse-per-second signal;

[0016] The timing module is configured to perform timing synchronization using a valid pulse-per-second signal determined based on the plurality of pulse-per-second signals and a local time.

[0017] In a third aspect, an air interface timing system is proposed, comprising: a reference base station, and a terminal that executes the method described in the first aspect.

[0018] In a fourth aspect, a storage medium is proposed for computer-readable storage, wherein the storage medium stores one or more programs, and when the one or more programs can be executed by one or more processors, the steps of the air interface timing method described above are implemented.

[0019] As can be seen from the technical solutions provided by one or more embodiments of the present specification, the terminal recovers the radio frame header of the base station based on the TA sent by the base station and maintains the frame number corresponding to the radio frame header; at the same time, the terminal determines the initial pulse per second signal based on the SIB9 broadcast by the base station. Afterwards, the terminal maintains multiple subsequent pulse per second signals locally based on the initial pulse per second signal, and uses the effective pulse per second signal obtained by filtering and smoothing the multiple pulse per second signals and the local time to perform timing synchronization. Since the absolute time information used to determine the initial pulse per second signal carried in the SIB9 is obtained by the base station through PTP or GNSS, and the initial pulse per second signal and the effective pulse per second signal determined by the subsequent multiple pulse per second signals maintained by the initial pulse per second signal are used for timing synchronization, it is possible to ensure synchronization accuracy at the nanosecond level, and reduce the impact of air interface channel quality on the timing scheme through at least three aspects such as the radio frame header maintenance mechanism, filtering, and smoothing. At the same time, the stability and synchronization accuracy of air interface timing are improved in universal ubiquitous Internet of Things scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the description of one or more embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic diagram of the air interface timing scenario involved in the embodiments of this specification.

[0022] Figure 2 This is one of the step diagrams of an air interface timing method provided in an embodiment of this specification.

[0023] Figure 3a This is a simplified flow chart of air-interface timing provided by the embodiment of this specification.

[0024] Figure 3b This is a schematic diagram of the principle of a terminal using uplink and downlink to recover a radio frame header of a base station provided by an embodiment of this specification.

[0025] Figure 4 This is a schematic diagram of the step 204 of determining the initial pulse per second signal provided in an embodiment of this specification.

[0026] Figure 5 This is a schematic diagram of a wireless frame involved in timing provided in an embodiment of the specification.

[0027] Figure 6 This is the second step diagram of an air interface timing method provided in an embodiment of this specification.

[0028] Figure 7 This is the third step diagram of an air interface timing method provided in the embodiment of this specification.

[0029] Figure 8 This is a schematic diagram of the terminal structure provided in the embodiments of this specification.

[0030] Figure 9a This is a schematic diagram of the structure of an air interface timing system provided in an embodiment of this specification.

[0031] Figure 9b This is a structural diagram of another air interface timing system provided in an embodiment of this specification. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the one or more embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this document.

[0033] To address the aforementioned issues, the present invention provides a nanosecond-level, high-precision 5G air interface timing solution while ensuring protocol compatibility. In a specific implementation, a terminal recovers the base station's radio frame header based on the TA sent by the base station and maintains the frame number corresponding to the radio frame header. Simultaneously, the terminal determines an initial pulse per second (PPS) signal based on the SIB9 broadcast by the base station. The terminal then locally maintains multiple subsequent PPS signals based on the initial PPS signal and uses the valid PPS signal obtained by filtering and smoothing the multiple PPS signals, along with the local time, for timing synchronization. Because the absolute time information used to determine the initial PPS signal carried in the SIB9 is obtained by the base station via PTP or GNSS, and timing synchronization is performed using the initial PPS signal and the valid PPS signal determined by maintaining the initial PPS signal with multiple subsequent PPS signals, nanosecond-level synchronization accuracy can be guaranteed. Through at least three mechanisms—the radio frame header maintenance mechanism, filtering, and smoothing—the impact of air interface channel quality on the timing solution is reduced, thereby improving the stability and synchronization accuracy of air interface timing in ubiquitous IoT scenarios.

[0034] The terminal in the embodiments of the present application may refer to user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device may also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a future 5G network or a terminal device in a future evolved public land mobile network (PLMN), etc., and the embodiments of the present application are not limited to this.

[0035] Reference Figure 1 As shown, it is a schematic diagram of the air interface timing scenario involved in the embodiments of this specification. In this air interface timing scenario, the terminal 102 to be synchronized and the base station 104 exchange information to complete the air interface timing. Before this, the base station 104 needs to obtain absolute time information through the clock server 106 (Precision Time Protocol, PTP; or Global Navigation Satellite System, GNSS) and synchronize the terminal time based on the absolute time information. The specific air interface timing solution is detailed in the following embodiments.

[0036] Example 1

[0037] Reference Figure 2 The figure shows a schematic diagram of the steps of an air interface timing method provided in an embodiment of this specification. It should be understood that this method is applied on the terminal side. The terminal can be a hardware terminal device or a software terminal module capable of exchanging air interface information with a base station. The air interface timing method may include the following steps:

[0038] Step 202: According to the timing advance TA sent by the base station, the radio frame header of the base station is restored, and the frame number corresponding to the radio frame header is maintained.

[0039] In the embodiment of this specification, when step 202 recovers the radio frame header of the base station according to the timing advance TA sent by the base station and maintains the frame number corresponding to the radio frame header, it can be specifically performed as follows:

[0040] The first step is to receive the timing advance TA sent by the base station.

[0041] The second step is to maintain the local uplink radio frame header according to the TA, and maintain the local downlink radio frame header according to the time offset determined by the reference signal sent by the base station.

[0042] In this step, the TA is measured by the base station based on signals transmitted by the terminal's uplink omnidirectional antenna. The base station uses beamforming technology to send downlink timing signaling, resulting in asymmetric uplink and downlink signal propagation paths. Therefore, this solution only uses the TA to maintain the local uplink radio frame header. For the downlink radio frame header, the time offset is determined based on the reference signal sent by the base station. This ensures the accuracy of the maintained uplink and downlink radio frame headers.

[0043] In the third step, the wireless frame header of the base station is restored based on the maintained uplink wireless frame header and downlink wireless frame header, and the frame number corresponding to the wireless frame header is maintained.

[0044] The base station obtains the synchronization error TA (Timing Advance) between the terminal and the base station through the existing time phase measurement method, and smoothes the TA before sending it to the terminal; Figure 3a As shown in the figure, when a terminal with communication and timing function blocks is connected to a 5G base station, the terminal can filter the TA sent by the 5G base station, remove abnormally large values, and then maintain the terminal's uplink wireless frame header according to the TA, and further maintain the downlink wireless frame header according to the time offset measured by the terminal, thereby maintaining uplink and downlink synchronization with the base station. Afterwards, the terminal recovers the 5G base station's wireless frame header based on the maintained uplink wireless frame header and downlink wireless frame header, and maintains the frame number corresponding to the wireless frame header. Figure 3b As shown, the terminal uses its own timing function to maintain the uplink wireless frame header L UL and downlink wireless frame header L DL Recover the wireless frame header L of the 5G base station eNB , and maintain the frame number FN corresponding to the wireless frame header. Specifically, the following formula can be used to determine the wireless frame header L of the base station. eNB :L eNB =L UL +1 / 2*(L DL -L UL ).

[0045] It should be understood that the synchronization accuracy of the uplink wireless frame header and the downlink wireless frame header maintained by the terminal is the basis of the PPS (i.e., the pulse per second signal described in this article) accuracy. If the current synchronization accuracy is at the nanosecond level, the subsequent steps of the present invention can make the PPS accuracy reach the nanosecond level.

[0046] Step 204: Obtain the system information block SIB9 broadcast by the base station, and determine the initial pulse per second signal based on SIB9 and the frame number, wherein SIB9 carries the absolute time information obtained by the base station through PTP or GNSS.

[0047] The base station should be understood as a 5G base station; what is different from the prior art is that the time information received by the terminal is sent by the 5G base station through SIB9. In specific implementation, the 5G base station is synchronized through PTP / GNSS to obtain the absolute time of PTP / GNSS. Afterwards, when the 5G base station sends the broadcast message System Information Block 9 (SIB9), based on the obtained correspondence between the frame number and time, it is inferred that the absolute time information corresponding to the wireless frame at the boundary of the SI-window (SIB window) where SIB9 is located is to be sent, and the absolute time information at this time is encapsulated into the SIB9 message and sent to the terminal to be synchronized in the form of a broadcast. Since the Coordinated Universal Time (UTC) contained in SIB9 has a higher time accuracy of up to 10ns, and the encapsulated absolute time information is obtained through a nanosecond-level clock server such as PTP or GNSS, the timing accuracy at the nanosecond level can be guaranteed.

[0048] Optionally, in step 204, when obtaining the system information block SIB9 broadcast by the base station and determining the initial pulse per second signal based on SIB9 and the frame number, refer to Figure 4 As shown, it can be specifically implemented as follows:

[0049] Step 402: Based on the maintained frame number, the absolute time information of the reference frame boundary and the frame number of the reference frame are parsed from SIB9.

[0050] Step 404: Based on the frame number, match the reference frame from the wireless frame header of the base station.

[0051] Step 406 determines the initial pulse-second count signal based on the frame number of the reference frame and the portion of the absolute time information that is less than the minimum integer second. Specifically, the number of radio frames occupied by the portion of the absolute time information of the reference frame that is less than 1 second is subtracted from the number of radio frames included in the interval between the two pulse-second count signals. The absolute value of this difference is added to the frame number of the reference frame to determine the frame number of the initial pulse-second count signal.

[0052] After receiving the broadcast message SIB9, the terminal parses the absolute time information T0 and frame number FN of the reference frame boundary from SIB9, where the unit of T0 is 10ms. eNB Match the reference frame according to the frame number, and then get the frame number FN of PP1S (the absolute time of PP1S is an integer second) according to the time information of the reference frame PP1S :FN PP1S =100-T0'+FN, where T0' is the remaining time information after removing the integer seconds from T0. This frame number is the initial FN PP1S , thus generating the initial PP1S. Figure 5 The figure shows a schematic diagram of the radio frame involved in timing. According to the absolute time T0' of the reference frame solved in SIB9, the frame number FN is X, and the frame number of PP1S is 100-Y+X. The radio frame header L of the base station corresponding to this frame is eNB Just for PP1S.

[0053] Step 206: Locally maintain a plurality of subsequent pulse-per-second signals based on the initial pulse-per-second signal.

[0054] Based on the local time information and the initial pulse-per-second signal, a subsequent pulse-per-second signal is determined every 100 radio frame numbers.

[0055] It should be understood that in actual timing synchronization, the locally maintained PPS can be used for time synchronization later. This is because the timing function of the terminal is affected by factors such as channel quality, SIB9 transmission stability, and disconnection. Sometimes, incorrect time information in SIB9 is received or SIB9 is not received. Therefore, the terminal needs to maintain and use local time information local_FNPPS, based on the initial FN PPS Every 100th wireless frame number is the frame number of the subsequent PPS. In addition to the initial pulse per second signal PPS, the subsequent PPS is based on local_FN PP1S To produce.

[0056] Step 208: Perform timing synchronization using the valid pulse per second signal determined based on the plurality of pulse per second signals and the local time.

[0057] This step 208 can be implemented according to the existing timing synchronization operation, so that the terminal is synchronized to the time of the base station. It should be understood that the valid second pulse number signal can be the second pulse number signal determined by the currently received SIB9 analysis, for example, it can be the initial second pulse number signal, or it can be the second pulse number signal determined by the subsequent newly received SIB9. Alternatively, it can also be the second pulse number signal that is most recently determined based on the locally maintained second pulse number signal; considering that the communication module of the terminal is affected by factors such as multipath, multi-beam, and air interface channel quality, the maintained uplink frame header and downlink frame header are sometimes inaccurate. Therefore, after determining the valid second pulse number signal, or after determining each second pulse number signal, the following formula can also be used to perform length smoothing on the second pulse number signal:

[0058] A=A+(BA) / 2 N

[0059] Where A is the length of the pulse per second signal after smoothing, B is the length of the pulse per second signal before smoothing, and N is the update threshold. Figure 5 As shown, according to the uplink wireless frame header L maintained ULand downlink wireless frame header L DL Restore the base station's wireless frame header L eNB There is jitter, which occurs in advance when the frame number FN is 200-Y+X, causing the length of the second second B2 to be smaller than the length of the first second B1. Through smoothing, the length of the second second is corrected to A2=A1+(B2-A1) / 2 N It can be seen that after smoothing, the influence of channel factors on timing stability is reduced, and the timing standard deviation is smaller.

[0060] Optionally, refer to Figure 6 As shown, before step 208 uses the effective pulse per second signal determined based on the plurality of pulse per second signals and the local time to perform timing synchronization, the method further includes:

[0061] Step 210: Determine whether the number of times that the locally maintained multiple pulse-second count signals differ from the pulse-second count signal determined by SIB9 analysis in terms of time information reaches an update threshold; if so, the currently received SIB9-analyzed pulse-second count signal is determined as the valid pulse-second count signal; otherwise, the most recently determined pulse-second count signal among the locally maintained multiple pulse-second count signals is used as the valid pulse-second count signal. PPS When the number of times the time information in SIB9 is different from the time information in SIB9 reaches the update threshold (configurable), the local time information is updated; Figure 5 As shown, if the time information carried in SIB9 is wrong or SIB9 cannot be received, the calculated PPS frame number FN will be PPS Error. If used directly, an incorrect PPS will be generated. Therefore, the locally maintained time information local_FN should be used. PPS Compare with the one received by SIB9. If the update threshold is reached, the pulse-per-second signal parsed by SIB9 (the most recently received pulse-per-second signal parsed by SIB) is used as the valid pulse-per-second signal. If the update threshold is not reached, it means that the locally maintained pulse-per-second signal is still available, then the latest locally maintained pulse-per-second signal is used as the valid pulse-per-second signal.

[0062] Optionally, based on the above solution, after timing synchronization, refer to Figure 7 As shown, the method further includes: Step 212: broadcasting the synchronized time information to other terminals via a specific interface supported by the terminal (such as the IRIG code in the power grid) to facilitate timing synchronization of other terminals. Thus, timing synchronization between terminals in the ubiquitous Internet of Things scenario can be achieved.

[0063] Through the above technical solution, the terminal recovers the radio frame header of the base station based on the TA sent by the base station and maintains the frame number corresponding to the radio frame header. At the same time, the terminal determines the initial pulse-per-second signal based on the SIB9 broadcast by the base station. Afterwards, the terminal locally maintains multiple subsequent pulse-per-second signals based on the initial pulse-per-second signal and uses the effective pulse-per-second signal obtained by filtering and smoothing the multiple pulse-per-second signals and the local time for timing synchronization. Because the absolute time information used to determine the initial pulse-per-second signal carried in the SIB9 is obtained by the base station through PTP or GNSS, and the initial pulse-per-second signal and the effective pulse-per-second signal determined by the subsequent multiple pulse-per-second signals maintained by the initial pulse-per-second signal are used for timing synchronization, it is possible to ensure synchronization accuracy at the nanosecond level. Through at least three aspects of the radio frame header maintenance mechanism, filtering, and smoothing, the impact of air interface channel quality on the timing scheme is reduced, and at the same time, the stability and synchronization accuracy of air interface timing are improved in universal ubiquitous Internet of Things scenarios.

[0064] Example 2

[0065] Reference Figure 8 FIG. 8 is a schematic diagram of a terminal structure provided in an embodiment of this specification. The terminal 800 may include:

[0066] The recovery module 802 is configured to recover the radio frame header of the base station according to the timing advance TA sent by the base station, and maintain the frame number corresponding to the radio frame header;

[0067] A determination module 804 is configured to obtain a system information block SIB9 broadcast by the base station, and determine an initial pulse per second signal based on the SIB9 and a frame number, wherein the SIB9 carries absolute time information obtained by the base station through PTP or GNSS;

[0068] A maintenance module 806 is configured to locally maintain subsequent multiple pulse-per-second number signals based on the initial pulse-per-second number signal;

[0069] The timing module 808 is configured to perform timing synchronization using a valid pulse per second signal determined based on a plurality of pulse per second signals and the local time.

[0070] Optionally, as an embodiment, when the recovery module 802 recovers the wireless frame header of the base station according to the timing advance TA sent by the base station and maintains the frame number corresponding to the wireless frame header, it is specifically used to: receive the timing advance TA sent by the base station; maintain the local uplink wireless frame header according to TA, and maintain the local downlink wireless frame header according to the time offset determined by the reference signal sent by the base station; recover the wireless frame header of the base station based on maintaining the uplink wireless frame header and the downlink wireless frame header, and maintain the frame number corresponding to the wireless frame header.

[0071] In a specific implementation of the embodiments of this specification, when the determination module 804 obtains the system information block SIB9 broadcast by the base station and determines the initial second pulse number signal based on SIB9 and the frame number, it is specifically used to: parse the absolute time information of the reference frame boundary and the frame number of the reference frame from SIB9 based on the maintained frame number; match the reference frame from the wireless frame header of the base station based on the frame number; and determine the initial second pulse number signal based on the frame number of the reference frame and the part of the absolute time information that is less than the minimum integer second.

[0072] In another specific implementation of the embodiments of this specification, when determining the initial pulse-per-second signal based on the frame number of the reference frame and the portion of the absolute time information that is less than a minimum integer second, the determination module 804 is specifically configured to: subtract the number of radio frames occupied by the portion of the absolute time information of the reference frame that is less than 1 second from the number of radio frames included in the interval between two pulse-per-second signals; and add the absolute value of the obtained difference to the frame number of the reference frame to obtain the frame number of the initial pulse-per-second signal.

[0073] In another specific implementation of the embodiment of this specification, when the maintenance module 806 locally maintains multiple subsequent second pulse number signals based on the initial second pulse number signal, it is specifically used to: determine a subsequent second pulse number signal every 100 wireless frame numbers based on local time information and the initial second pulse number signal.

[0074] In another specific implementation of the embodiments of this specification, the terminal also includes: a judgment module, which is used to judge whether the number of times that the locally maintained multiple second pulse number signals and the second pulse number signal determined by SIB9 analysis are continuously different in time information reaches an update threshold before the timing module 808 uses the valid second pulse number signal determined based on multiple second pulse number signals and the local time for timing synchronization; if so, the second pulse number signal determined by the currently received SIB9 analysis is determined as the valid second pulse number signal; otherwise, the most recently determined second pulse number signal among the multiple locally maintained second pulse number signals is used as the valid second pulse number signal.

[0075] In another specific implementation of the embodiment of this specification, the terminal further includes: a smoothing module, configured to perform length smoothing processing on the effective pulse second number signal using the following formula before using the effective pulse second number signal determined based on the multiple pulse second number signals and the local time for timing synchronization:

[0076] A=A+(BA) / 2N

[0077] Where A is the effective pulse-per-second signal length after smoothing, B is the effective pulse-per-second signal length before smoothing, and N is the update threshold.

[0078] In another specific implementation of the embodiment of this specification, the timing module 808 is further configured to broadcast the synchronized time information to other terminals via a specific interface supported by the terminal, so as to facilitate timing synchronization of other terminals.

[0079] Through the above technical solution, the terminal recovers the radio frame header of the base station based on the TA sent by the base station and maintains the frame number corresponding to the radio frame header. At the same time, the terminal determines the initial pulse-per-second signal based on the SIB9 broadcast by the base station. Afterwards, the terminal locally maintains multiple subsequent pulse-per-second signals based on the initial pulse-per-second signal and uses the effective pulse-per-second signal obtained by filtering and smoothing the multiple pulse-per-second signals and the local time for timing synchronization. Because the absolute time information used to determine the initial pulse-per-second signal carried in the SIB9 is obtained by the base station through PTP or GNSS, and the initial pulse-per-second signal and the effective pulse-per-second signal determined by the subsequent multiple pulse-per-second signals maintained by the initial pulse-per-second signal are used for timing synchronization, it is possible to ensure synchronization accuracy at the nanosecond level. Through at least three aspects of the radio frame header maintenance mechanism, filtering, and smoothing, the impact of air interface channel quality on the timing scheme is reduced, and at the same time, the stability and synchronization accuracy of air interface timing are improved in universal ubiquitous Internet of Things scenarios.

[0080] Example 3

[0081] Reference Figure 9a FIG. 1 shows a schematic diagram of the structure of an air interface timing system provided in an embodiment of this specification. The air interface timing system may include: a reference base station 902 and a terminal to be synchronized 904. Terminal to be synchronized 904 may synchronize with reference base station 902 according to the solution shown in Example 1. This system can achieve timing synchronization between terminals and base stations in the ubiquitous power Internet of Things scenario.

[0082] Further, refer to Figure 9b FIG2 is a schematic diagram of another air interface timing system structure provided by an embodiment of this specification. The air interface timing system may include: a reference base station 901, a timing terminal 903, and a terminal to be synchronized 905. The timing terminal 903 may synchronize timing with the reference base station 901 according to the solution of the first embodiment. After obtaining the synchronized time, the synchronized time is broadcast to the terminal to be synchronized 905 via the 5G module. This system can achieve terminal-to-terminal timing synchronization through broadcast in the ubiquitous power Internet of Things scenario.

[0083] In an embodiment of the present specification, the terminal recovers the radio frame header of the base station based on the TA sent by the base station and maintains the frame number corresponding to the radio frame header. At the same time, the terminal determines the initial pulse-per-second signal based on the SIB9 broadcast by the base station. Afterwards, the terminal locally maintains multiple subsequent pulse-per-second signals based on the initial pulse-per-second signal and uses the valid pulse-per-second signal obtained by filtering and smoothing the multiple pulse-per-second signals and the local time to perform timing synchronization. Since the absolute time information used to determine the initial pulse-per-second signal carried in the SIB9 is obtained by the base station through PTP or GNSS, and the initial pulse-per-second signal and the valid pulse-per-second signal determined by the subsequent multiple pulse-per-second signals maintained by the initial pulse-per-second signal are used for timing synchronization, it is possible to ensure synchronization accuracy at the nanosecond level. Through at least three aspects of the radio frame header maintenance mechanism, filtering, and smoothing, the impact of air interface channel quality on the timing scheme is reduced, and at the same time, the stability and synchronization accuracy of air interface timing are improved in universal ubiquitous Internet of Things scenarios.

[0084] Example 4

[0085] An embodiment of the present invention provides a storage medium for computer-readable storage, wherein the storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the following steps:

[0086] Step 202: According to the timing advance TA sent by the base station, the radio frame header of the base station is restored, and the frame number corresponding to the radio frame header is maintained.

[0087] In an embodiment of the present specification, a timing advance TA sent by a base station can be received; a local uplink wireless frame header is maintained based on the TA, and a local downlink wireless frame header is maintained based on a time offset determined by a reference signal sent by the base station; a wireless frame header of the base station is restored based on the maintained uplink wireless frame header and downlink wireless frame header, and a frame number corresponding to the wireless frame header is maintained.

[0088] It should be understood that the synchronization accuracy of the uplink wireless frame header and the downlink wireless frame header maintained by the terminal is the basis of the PPS (i.e., the pulse per second signal described in this article) accuracy. If the current synchronization accuracy is at the nanosecond level, the subsequent steps of the present invention can make the PPS accuracy reach the nanosecond level.

[0089] Step 204: Obtain the system information block SIB9 broadcast by the base station, and determine the initial pulse per second signal based on SIB9 and the frame number, wherein SIB9 carries the absolute time information obtained by the base station through PTP or GNSS.

[0090] The base station should be understood as a 5G base station; what is different from the existing technology is that the time information received by the terminal is sent by the 5G base station through SIB9. In specific implementation, the 5G base station is synchronized through PTP / GNSS to obtain the absolute time of PTP / GNSS. Afterwards, when the 5G base station sends the broadcast message SIB9, based on the obtained correspondence between the frame number and time, it is inferred that the absolute time information corresponding to the wireless frame at the boundary of the SI-window (SIB window) where SIB9 is located is to be sent, and the absolute time information at this time is encapsulated into the SIB9 message and sent to the terminal to be synchronized in the form of a broadcast. Since the international coordinated time (Coordinated Universal Time, UTC) contained in SIB9 has a higher time accuracy of up to 10ns, and the encapsulated absolute time information is obtained through a nanosecond-level clock server such as PTP or GNSS, the timing accuracy at the nanosecond level can be guaranteed.

[0091] After receiving the broadcast message SIB9, the terminal parses the absolute time information T0 and frame number FN of the reference frame boundary from SIB9, where the unit of T0 is 10ms. eNB Match the reference frame according to the frame number, and then get the frame number FN of the PPS (the absolute time of the PPS is an integer second) according to the time information of the reference frame PPS :FN PPS =100-T0'+FN, where T0' is the remaining time information after removing the integer seconds from T0. This frame number is the initial FN PPS , thus generating the initial PPS. Figure 5 The figure shows a schematic diagram of the radio frame involved in timing. According to the absolute time T0' of the reference frame solved in SIB9, the frame number FN is X, and the frame number of the PPS is 100-Y+X. The radio frame header L of the base station corresponding to this frame is eNB Just for PPS.

[0092] Step 206: Locally maintain a plurality of subsequent pulse-per-second signals based on the initial pulse-per-second signal.

[0093] It should be understood that in actual timing synchronization, the locally maintained PPS can be used for time synchronization later. This is because the timing function of the terminal is affected by factors such as channel quality, SIB9 transmission stability, and disconnection. Sometimes, incorrect time information in SIB9 is received or SIB9 is not received. Therefore, the terminal needs to maintain and use local time information local_FN PPS , according to the initial FN PPS Every 100th radio frame number is the frame number of the subsequent PPS. Except for the initial PPS, the subsequent PPS is based on local_FN PPSTo produce.

[0094] Step 208: Perform timing synchronization using the valid pulse per second signal determined based on the plurality of pulse per second signals and the local time.

[0095] Considering that the communication module of the terminal is affected by factors such as multipath, multi-beam, and air interface channel quality, the maintained uplink frame header and downlink frame header may sometimes be inaccurate. Therefore, after determining each pulse second number signal, or before using the valid pulse second number signal determined based on the multiple pulse second number signals and the local time for timing synchronization, the following formula can also be used to perform length smoothing on the pulse second number signal:

[0096] A=A+(BA) / 2N

[0097] Wherein, A is the length of the pulse-per-second signal after smoothing, B is the length of the pulse-per-second signal before smoothing, and N is the update threshold.

[0098] Furthermore, before performing timing synchronization using the valid pulse per second signal determined based on the plurality of pulse per second signals and the local time in step 208, the method further includes:

[0099] Step 210: Determine whether the number of times that the locally maintained multiple pulse-second count signals differ from the pulse-second count signal determined by SIB9 analysis in terms of time information reaches an update threshold; if so, the currently received SIB9-analyzed pulse-second count signal is determined as the valid pulse-second count signal; otherwise, the most recently determined pulse-second count signal among the locally maintained multiple pulse-second count signals is used as the valid pulse-second count signal. PPS When the number of times the time information in SIB9 is different from the time information in SIB9 reaches the update threshold (configurable), the local time information is updated; Figure 5 As shown, if the time information carried in SIB9 is wrong or SIB9 cannot be received, the calculated PPS frame number FN will be PPS Error. If used directly, an incorrect PPS will be generated. Therefore, SIB9 needs to use the locally maintained time information local_FN PPS Compare it with what SIB9 received and generate PPS.

[0100] Further analysis shows that based on the above solution, after timing synchronization, the following steps are also required:

[0101] Step 212: The synchronized time information is broadcast to other terminals via a specific interface supported by the terminal, so that other terminals can synchronize their timing. Thus, timing synchronization between terminals in a ubiquitous Internet of Things scenario can be achieved.

[0102] The above analysis shows that the terminal recovers the base station's radio frame header based on the TA sent by the base station and maintains the frame number corresponding to the radio frame header. Simultaneously, the terminal determines the initial PPS signal based on the SIB9 broadcast by the base station. Subsequently, the terminal locally maintains multiple subsequent PPS signals based on this initial PPS signal and uses the valid PPS signal obtained by filtering and smoothing these multiple PPS signals, along with the local time, for timing synchronization. Because the absolute time information used to determine the initial PPS signal carried in the SIB9 is obtained by the base station via PTP or GNSS, and timing synchronization is performed using the initial PPS signal and the valid PPS signal determined by multiple subsequent PPS signals maintained by the initial PPS signal, synchronization can be guaranteed to nanoseconds. Through at least three mechanisms—the radio frame header maintenance mechanism, filtering, and smoothing—the terminal mitigates the impact of air interface channel quality on the timing solution, improving the stability and synchronization accuracy of air interface timing in ubiquitous IoT scenarios.

[0103] In short, the above description is only a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this specification should be included in the scope of protection of this specification.

[0104] The systems, devices, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0105] Computer-readable storage media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0106] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0107] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0108] The foregoing description of this specification describes specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that described in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. An air interface timing method, applied to a terminal side, comprising: Recover the radio frame header of the base station according to the timing advance TA issued by the base station, and maintain the frame number corresponding to the radio frame header; Obtaining a system information block SIB9 broadcast by a base station, and determining an initial pulse per second signal based on the SIB9 and the frame number, wherein the SIB9 carries absolute time information obtained by the base station through PTP or GNSS; locally maintaining a subsequent plurality of pulse-per-second signals based on the initial pulse-per-second signal; Timing synchronization is performed using an effective pulse-per-second signal determined based on the plurality of pulse-per-second signals and local time.

2. The air interface timing method according to claim 1, further comprising: recovering a radio frame header of the base station according to the timing advance TA issued by the base station, and maintaining a frame number corresponding to the radio frame header; Receive the timing advance TA sent by the base station; Maintaining a local uplink radio frame header according to the TA, and maintaining a local downlink radio frame header according to a time offset determined by a reference signal sent by a base station; The radio frame header of the base station is restored based on the maintained uplink radio frame header and the downlink radio frame header, and the frame number corresponding to the radio frame header is maintained.

3. The air interface timing method according to claim 1, wherein obtaining a system information block SIB9 broadcast by a base station and determining an initial pulse per second signal based on the SIB9 and the frame number further comprises: Parsing absolute time information of a reference frame boundary and a frame number of a reference frame from the SIB9 based on the maintained frame number; Matching the reference frame from a radio frame header of a base station based on the frame number; The initial second pulse number signal is determined according to the frame number of the reference frame and the portion of the absolute time information that is less than a minimum integer second.

4. The air interface timing method according to claim 3, wherein determining the initial pulse per second signal based on the frame number of the reference frame and the portion of the absolute time information that is less than a minimum integer second specifically comprises: Subtract the number of radio frames occupied by the portion less than 1 second in the absolute time information of the reference frame from the number of radio frames contained in the interval of two pulse-per-second signals; The absolute value of the obtained difference is added to the frame number of the reference frame to obtain the frame number of the initial pulse per second signal.

5. The air interface timing method according to claim 1, wherein locally maintaining a plurality of subsequent pulse per second (PPS) signals based on the initial PPS signal comprises: Based on the local time information and the initial pulse-per-second signal, a subsequent pulse-per-second signal is determined every 100 radio frame numbers.

6. The air interface timing method according to claim 1 or 5, before performing timing synchronization using the effective pulse per second signal determined based on the plurality of pulse per second signals and the local time, the method further comprises: determining whether the number of times that the locally maintained plurality of pulse-per-second signals and the pulse-per-second signal determined by SIB9 analysis are consecutively different in time information reaches an update threshold; If yes, the pulse-per-second signal determined by parsing the currently received SIB9 is determined as a valid pulse-per-second signal; Otherwise, the most recently determined pulse-per-second signal among the plurality of pulse-per-second signals maintained locally is used as the valid pulse-per-second signal.

7. The air interface timing method according to claim 6, further comprising: before performing timing synchronization using the effective pulse per second signal determined based on the plurality of pulse per second signals and the local time; The effective pulse per second signal is smoothed using the following formula: A=A+(B-A) / 2 N Wherein, A is the effective pulse-per-second signal length after smoothing, B is the effective pulse-per-second signal length before smoothing, and N is the update threshold.

8. The air interface timing method according to any one of claims 1 to 5 and 7, further comprising, after performing timing synchronization: The synchronized time information is broadcast to other terminals through a specific interface supported by the terminal, so that other terminals can synchronize their timing.

9. A terminal comprising: A recovery module, configured to recover a radio frame header of the base station according to a timing advance TA sent by the base station, and maintain a frame number corresponding to the radio frame header; a determination module, configured to obtain a system information block SIB9 broadcast by the base station and determine an initial pulse per second signal, wherein the SIB9 carries absolute time information obtained by the base station through PTP or GNSS; a maintenance module, configured to locally maintain a plurality of subsequent pulse-per-second signals based on the initial pulse-per-second signal; The timing module is configured to perform timing synchronization using a valid pulse-per-second signal determined based on the plurality of pulse-per-second signals and a local time.

10. The terminal according to claim 9, wherein the timing module is further configured to: The synchronized time information is broadcast to other terminals through a specific interface supported by the terminal, so that other terminals can synchronize their timing.

11. An air interface timing system, comprising: Reference base station, and a terminal that executes the method according to any one of claims 1 to 8.

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