阅读说明：本技术 基于自组网的网络定时同步方法及系统 (Network timing synchronization method and system based on ad hoc network ) 是由 刘建德 梁宏建 倪吉庆 李秉权 于 2021-08-23 设计创作，主要内容包括：本发明涉及无线通信技术领域,提供了一种基于自组网的网络定时同步方法及系统。该方法包括：当自组网中任一终端发出同步信号时,自组网的至少一个待同步终端在同步信道检测同步信号,并获取同步信号的属性信息,待同步终端基于属性信息中的功率值及/或能量值,与同步信号进行定时同步,待同步终端基于同步信号的预设触发条件,判断是否发送同步信号,当判断任一待同步终端发送同步信号时,根据检测到的同步信号的个数及/或同步信号的能量值调整同步信号的发送周期。本发明可以解决远距离传输场景下的网络定时同步问题,且可以自适应调整同步信号发送周期,提升网络定时同步的效率。(The invention relates to the technical field of wireless communication, and provides a network timing synchronization method and system based on an ad hoc network. The method comprises the following steps: when any terminal in the ad hoc network sends out a synchronous signal, at least one terminal to be synchronized of the ad hoc network detects the synchronous signal in a synchronous channel and acquires attribute information of the synchronous signal, the terminal to be synchronized carries out timing synchronization with the synchronous signal based on a power value and/or an energy value in the attribute information, the terminal to be synchronized judges whether to send the synchronous signal or not based on a preset trigger condition of the synchronous signal, and when any terminal to be synchronized is judged to send the synchronous signal, the sending period of the synchronous signal is adjusted according to the number of the detected synchronous signals and/or the energy value of the synchronous signal. The invention can solve the problem of network timing synchronization in a long-distance transmission scene, can adaptively adjust the sending period of the synchronous signal and improve the efficiency of network timing synchronization.)

1. A network timing synchronization method based on ad hoc network is characterized in that the method comprises the following steps:

and when the terminal to be synchronized sends the synchronization signals, adjusting the sending period of the synchronization signals according to the number of the detected synchronization signals and/or the energy value of the synchronization signals.

2. The ad hoc network-based network timing synchronization method according to claim 1, wherein the condition for the terminal to be synchronized to send the synchronization signal comprises:

when any terminal in the ad hoc network sends out a synchronization signal, at least one terminal to be synchronized of the ad hoc network detects the synchronization signal in a synchronization channel and acquires the attribute information of the synchronization signal;

the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information;

the terminal to be synchronized judges whether to send the synchronization signal or not based on a preset trigger condition of the synchronization signal;

and when any terminal to be synchronized is judged to send the synchronization signal, adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal.

3. The ad-hoc network-based network timing synchronization method according to claim 2, wherein after said determining a transmission period according to the number of detected synchronization signals and/or the energy value of the synchronization signals, the method further comprises:

and the adjacent terminal corresponding to the terminal to be synchronized which sends the synchronization signal carries out timing synchronization according to the synchronization signal.

4. The method according to claim 2 or 3, wherein the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information, and the method comprises:

a terminal to be synchronized acquires timing information from a synchronization signal to the local and sends access information to a sending terminal corresponding to the synchronization signal in an access channel;

a sending terminal corresponding to the synchronization signal sends a random access response to a terminal to be synchronized;

and the terminal to be synchronized acquires the random access response and acquires the ad hoc network timing information and/or the timing information of the local synchronization signal.

5. The ad-hoc network-based network timing synchronization method of claim 2 or 3, wherein the determining whether to send the synchronization signal by the terminal to be synchronized based on a preset trigger condition of the synchronization signal comprises:

the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal, and when the energy value is smaller than a first preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or, the terminal to be synchronized searches for the synchronization signal, receives the timing adjustment value of the synchronization signal, and when the timing adjustment value is greater than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or, the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal and receives the timing adjustment value of the synchronization signal, when the energy value is smaller than the first preset value or the timing adjustment value is larger than or equal to the second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or all the terminals to be synchronized transmit the synchronization signal.

6. The method for network timing synchronization based on ad hoc network according to claim 2 or 3, wherein said adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal comprises:

when the number of the synchronous signals detected by the terminal to be synchronized is larger than the preset number, increasing the sending period of the synchronous signals;

and when the number of the synchronous signals detected by the terminal to be synchronized is less than or equal to the preset number, reducing the sending period of the synchronous signals.

7. The ad-hoc network-based network timing synchronization method according to claim 2 or 3, wherein the attribute information of the synchronization signal further comprises: the method comprises the steps of identifying the ID of a synchronous signal, the time slot number of the synchronous signal and the period indication of the synchronous signal, wherein the ID of the synchronous signal comprises the physical layer ID or partial physical layer ID of a user, and the period indication is used for indicating the period of the terminal for sending the synchronous signal.

8. A network timing synchronization system based on ad hoc networks, the system comprising:

an adjusting unit: and the method is used for adjusting the sending period of the synchronous signals according to the number of the detected synchronous signals and/or the energy value of the synchronous signals when the terminal to be synchronized sends the synchronous signals.

9. The system of claim 8, further comprising a condition that the terminal to be synchronized transmits the synchronization signal comprises a judging unit:

the method comprises the steps that when any terminal in the ad hoc network sends a synchronization signal, at least one terminal to be synchronized of the ad hoc network detects the synchronization signal in a synchronization channel and acquires attribute information of the synchronization signal;

the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information;

the terminal to be synchronized judges whether to send the synchronization signal or not based on a preset trigger condition of the synchronization signal;

and when any terminal to be synchronized is judged to send the synchronization signal, adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal.

10. The system according to claim 9, wherein the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information, comprising:

a terminal to be synchronized acquires downlink timing information from a synchronization signal to the local and sends access information to a sending terminal corresponding to the synchronization signal in an access channel;

a sending terminal corresponding to the synchronization signal sends a random access response to a terminal to be synchronized;

and the terminal to be synchronized acquires the random access response and acquires the ad hoc network timing information and/or the uplink timing information of the local to synchronous signal.

Technical Field

The invention relates to the technical field of wireless communication, in particular to a network timing synchronization method and system based on an ad hoc network.

Background

Communication networks require synchronous timing techniques to ensure data transmission between points-to-points. Existing timing mechanisms of ad hoc networks mainly include a CSMA-based synchronization mechanism and a slot-based synchronization mechanism. Under a CSMA-based synchronization mechanism, a terminal detects signals all the time, estimates coarse timing when a peak value is searched, and further performs fine timing estimation based on subsequent signals. The timing mechanism does not need the timing synchronization of the whole network, and can realize point-to-point timing synchronization estimation.

Under the synchronization mechanism based on the time slot, a dedicated timing terminal (or one or a part of terminals in the network) periodically sends a synchronization signal, and other terminals detect the synchronization signal, so as to acquire the start position of the time slot. In addition, in consideration of the influence of propagation delay, other terminals may send signals to and from the timing terminal to realize timing synchronization between the terminals, and further realize full network synchronization, that is, a timing technique based on Round-trip-delay (RTT).

Currently, the 5GV2X standard supports a slot-based synchronization timing technique, which specifically includes: the terminal detects the synchronous signal, and if the synchronous signal is not detected or the detected energy of the synchronous signal is low, the terminal sends the synchronous signal according to a fixed period for synchronous timing of other terminals. And other terminals detect the broadcast signals based on the timing terminal, acquire information such as frame numbers/time slot numbers and the like, and determine specific time slot indexes so as to realize the whole network synchronization.

In the 5GV2X synchronization mechanism, synchronization IDs sent by different timing terminals are the same, and in the mechanism, other terminals cannot effectively distinguish different timing terminals, and cannot effectively support long-distance transmission based on RTT timing. In addition, under the current network timing mechanism based on time slots, the synchronization signals are generally sent in a fixed periodicity, and if the sending period is short, the number of terminals accessing the network is limited by the sending in the fixed periodicity; if the transmission period configuration is longer, the efficiency of timing synchronization is lower when the number of network users is less.

Disclosure of Invention

In view of the above, the present invention provides a method and system for network timing synchronization based on ad hoc network, which aims to solve the above technical problems.

In order to achieve the above object, the present invention provides a network timing synchronization method based on ad hoc network, the method comprising:

and when the terminal to be synchronized sends the synchronization signals, adjusting the sending period of the synchronization signals according to the number of the detected synchronization signals and/or the energy value of the synchronization signals.

Preferably, the condition that the terminal to be synchronized transmits the synchronization signal includes:

when any terminal in the ad hoc network sends out a synchronization signal, at least one terminal to be synchronized of the ad hoc network detects the synchronization signal in a synchronization channel and acquires the attribute information of the synchronization signal;

the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information;

the terminal to be synchronized judges whether to send the synchronization signal or not based on a preset trigger condition of the synchronization signal;

and when any terminal to be synchronized is judged to send the synchronization signal, adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal.

Preferably, after the determining the transmission period according to the number of detected synchronization signals and/or the energy value of the synchronization signals, the method further includes:

and the adjacent terminal corresponding to the terminal to be synchronized which sends the synchronization signal carries out timing synchronization according to the synchronization signal.

Preferably, the performing timing synchronization with the synchronization signal by the terminal to be synchronized based on the power value and/or the energy value in the attribute information includes:

a terminal to be synchronized acquires timing information from a synchronization signal to the local and sends access information to a sending terminal corresponding to the synchronization signal in an access channel;

a sending terminal corresponding to the synchronization signal sends a random access response to a terminal to be synchronized;

and the terminal to be synchronized acquires the random access response and acquires the ad hoc network timing information and/or the timing information of the local synchronization signal.

Preferably, the determining, by the terminal to be synchronized, whether to send the synchronization signal based on a preset trigger condition of the synchronization signal includes:

the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal, and when the energy value is smaller than a first preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or, the terminal to be synchronized searches for the synchronization signal, receives the timing adjustment value of the synchronization signal, and when the timing adjustment value is greater than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or, the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal and receives the timing adjustment value of the synchronization signal, when the energy value is smaller than the first preset value or the timing adjustment value is larger than or equal to the second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or all the terminals to be synchronized transmit the synchronization signal.

Preferably, the adjusting the transmission cycle of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal includes:

when the number of the synchronous signals detected by the terminal to be synchronized is larger than the preset number, increasing the sending period of the synchronous signals;

and when the number of the synchronous signals detected by the terminal to be synchronized is less than or equal to the preset number, reducing the sending period of the synchronous signals.

Preferably, the attribute information of the synchronization signal further includes: the method comprises the steps of identifying the ID of a synchronous signal, the time slot number of the synchronous signal and the period indication of the synchronous signal, wherein the ID of the synchronous signal comprises the physical layer ID or partial physical layer ID of a user, and the period indication is used for indicating the period of the terminal for sending the synchronous signal.

In order to achieve the above object, the present invention further provides a network timing synchronization system based on ad hoc network, the system comprising:

an adjusting unit: and the method is used for adjusting the sending period of the synchronous signals according to the number of the detected synchronous signals and/or the energy value of the synchronous signals when the terminal to be synchronized sends the synchronous signals.

Preferably, the system further includes a condition determining unit for the terminal to be synchronized to send the synchronization signal:

the method comprises the steps that when any terminal in the ad hoc network sends a synchronization signal, at least one terminal to be synchronized of the ad hoc network detects the synchronization signal in a synchronization channel and acquires attribute information of the synchronization signal;

the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information;

a transmission unit: the method comprises the steps that whether a synchronous signal is sent or not is judged by the terminal to be synchronized based on a preset trigger condition of the synchronous signal;

and when any terminal to be synchronized is judged to send the synchronization signal, adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal.

Preferably, the performing timing synchronization with the synchronization signal by the terminal to be synchronized based on the power value and/or the energy value in the attribute information includes:

a terminal to be synchronized acquires downlink timing information from a synchronization signal to the local and sends access information to a sending terminal corresponding to the synchronization signal in an access channel;

a sending terminal corresponding to the synchronization signal sends a random access response to a terminal to be synchronized;

and the terminal to be synchronized acquires the random access response and acquires the ad hoc network timing information and/or the uplink timing information of the local to synchronous signal.

Preferably, the determining, by the terminal to be synchronized, whether to send the synchronization signal based on a preset trigger condition of the synchronization signal includes:

the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal, and when the energy value is smaller than a first preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

the terminal to be synchronized searches for the synchronization signal, receives a timing adjustment value of the synchronization signal, and when the timing adjustment value is greater than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

and the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal and receives the timing adjustment value of the synchronization signal, when the energy value is smaller than a first preset value or the timing adjustment value is larger than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal.

Preferably, the adjusting the transmission cycle of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal includes:

when the number of the synchronous signals detected by the terminal to be synchronized is larger than the preset number, increasing the sending period of the synchronous signals;

and when the number of the synchronous signals detected by the terminal to be synchronized is less than or equal to the preset number, reducing the sending period of the synchronous signals.

The network timing synchronization method and system based on the ad hoc network can solve the problem of network timing synchronization in a long-distance transmission scene, the synchronization signal triggering condition is associated with the measured RSRP and TA, the topology of a terminal in the network which is used as a synchronization source can meet the configuration requirement, the synchronization period can be adjusted in a self-adaptive mode, the synchronization period can be reduced when fewer users exist, the access delay can be effectively reduced, and when more users exist, the synchronization period is increased to improve the number of user access in the network.

Drawings

Fig. 1 is a flowchart of a network timing synchronization method based on an ad hoc network according to the present invention;

fig. 2 is a flowchart of an embodiment of a network timing synchronization method based on an ad hoc network according to the present invention;

fig. 3 is a schematic diagram of a network timing synchronization system structure based on an ad hoc network according to the present invention;

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a flowchart of a network timing synchronization method based on ad hoc network according to the present invention. The method for synchronizing network timing based on ad hoc network as shown in fig. 1 comprises:

a1: when the terminal to be synchronized sends a synchronization signal;

a2: and adjusting the sending period of the synchronous signals according to the number of the detected synchronous signals and/or the energy value of the synchronous signals.

The synchronization period can be adjusted in a self-adaptive mode, the synchronization period can be reduced when the number of users is small, the access time delay can be effectively reduced, and when the number of users is large, the synchronization period is increased so as to increase the number of users accessed in a network.

Fig. 2 is a flowchart of a preferred embodiment of the network timing synchronization method based on the ad hoc network according to the present invention. The method for synchronizing network timing based on ad hoc network as shown in fig. 2 comprises:

s10: when any terminal in the ad hoc network sends out a synchronization signal, at least one terminal to be synchronized of the ad hoc network detects the synchronization signal in a synchronization channel and acquires the attribute information of the synchronization signal;

the self-organizing network is a network combining mobile communication and computer network, the information exchange of the network adopts the packet exchange mechanism in the computer network, the user terminal is a portable terminal which can be moved, and each user terminal in the self-organizing network has two functions of router and host. The scheme is explained by using a mixed transmission scene of the remote vehicle-mounted terminal and the close-range handheld terminal, and it can be understood that the actual scene of the scheme is not limited to the scene.

The configured time slots in the ad hoc network can transmit synchronization signals, which are defined as synchronization channels, and the interval between the synchronization channels is fixed, wherein the synchronization channel interval can be 160ms (one time slot is 2ms, corresponding to 80 time slots), and the synchronization transmission period is 640 ms. The synchronization channel interval has an access channel for other terminals to synchronize with the timing terminal, and specifically, the synchronization channel interval has a Physical Random Access (PRACH) channel and a Random Access Response (RAR) channel for carrying an access signal of an access user and a random access response sent by a synchronization source to the access user. The PRACH and RAR occupy 1 slot or multiple slots within one synchronization interval.

In this embodiment, when any terminal in the ad hoc network sends out a synchronization signal (which may be referred to as a synchronization source), at least one terminal to be synchronized (i.e. except for other terminals sending out the synchronization signal) of the ad hoc network detects the synchronization signal in a synchronization channel and acquires attribute information of the synchronization signal, where the attribute information of the synchronization signal includes power information and energy information (RSRP) of the synchronization signal, and further, the attribute information of the synchronization signal further includes: the ID of the synchronization signal, the slot number of the synchronization signal, and a period indication of the synchronization signal, where the period indication is used to indicate a period in which the terminal transmits the synchronization signal, ID information in the synchronization signal transmitted by the terminal is unique, for example, a physical layer ID (which may be a user physical layer ID or a partial physical layer ID), a corresponding value of each terminal is different, and the slot number is used by the terminal to determine a slot index.

A synchronous transmission period is indicated by 2 bits, a transmission period of 320ms is indicated by '00', a transmission period of 640ms is indicated by '01', a transmission period of 1.28s is indicated by '10', and a transmission period of 2.56s is indicated by '11'. It will be appreciated that the above indication is only one way of synchronizing signal configuration.

S20: the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information;

in this embodiment, other terminals of the ad hoc network (i.e., terminals to be synchronized) may determine whether to perform access timing synchronization based on the access channel or directly based on the synchronization source timing as the network timing according to the transmission power of the synchronization signal and/or the detected synchronization signal energy (RSRP).

In one embodiment, the performing timing synchronization with a synchronization signal by the terminal to be synchronized based on the power value and/or the energy value in the attribute information includes:

a terminal to be synchronized acquires timing information from a synchronization signal to the local and sends access information to a sending terminal corresponding to the synchronization signal in an access channel;

a sending terminal corresponding to the synchronization signal sends a random access response to a terminal to be synchronized;

and the terminal to be synchronized acquires the random access response and acquires the ad hoc network timing information and/or the timing information of the local synchronization signal.

And the terminal to be synchronized acquires timing information from a synchronization source to the local according to the synchronization detection, sends access information to the synchronization source in an access channel, the synchronization source sends a random access response to an access user, and the terminal to be synchronized acquires the random access response and acquires the timing information of the whole network and/or the timing information from the local to the synchronization source.

S30: the terminal to be synchronized judges whether to send the synchronization signal or not based on a preset trigger condition of the synchronization signal;

in this embodiment, the other terminals except for the terminal that sends the synchronization signal determine whether to send the synchronization signal based on the preset trigger condition of the synchronization signal.

In one embodiment, the determining, by the terminal to be synchronized, whether to send the synchronization signal based on a preset trigger condition of the synchronization signal includes:

the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal, and when the energy value is smaller than a first preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

the terminal to be synchronized searches for the synchronization signal, receives a timing adjustment value of the synchronization signal, and when the timing adjustment value is greater than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

and the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal and receives the timing adjustment value of the synchronization signal, when the energy value is smaller than a first preset value or the timing adjustment value is larger than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal.

In this embodiment, a dedicated timing terminal is provided, and the timing terminal may fixedly transmit the synchronization signal, or some or all of the terminals of the network terminal may be configured as the timing terminal.

When one of the following conditions is met, triggering the terminal to be synchronized to send the synchronization signal, otherwise not sending the synchronization signal, wherein the specific conditions for sending the synchronization signal comprise:

a terminal to be synchronized searches for a synchronization signal, and sends a synchronization block when the synchronization block is not detected within a period of time;

or, searching for a synchronization signal, measuring an RSRP value of the synchronization signal, a maximum RSRP of the measurements being below a first threshold value (e.g., -120 dBm);

or, searching for the synchronization signal, and receiving a Timing Advance (TA) sent by the synchronization signal, where the TA is greater than or equal to a second threshold (e.g., 16.67us, corresponding to a 5km range);

or searching for a synchronization signal, measuring RSRP and receiving a TA value, wherein the maximum RSRP measured is lower than a first threshold value, or the TA value is larger than a second threshold value. The threshold value can be set according to actual conditions.

Or all the terminals to be synchronized transmit the synchronization signal.

In one embodiment, the synchronization signal transmission trigger mode of the configuration mode transmits synchronization signals for all terminals for a total of 16 terminals in the network. The synchronization period of the synchronization channel is 640ms, 4 synchronization channels can be supported, and the synchronization period transmitted by the terminal supports 320/640/1280/2560 ms.

When initially establishing a network, the terminal 0 is started up at the earliest, and through synchronous signal detection, if a synchronous source is not detected within a period of time, a synchronous channel is selected based on local timing to send a synchronous signal, wherein the period is 320 ms.

And the subsequent terminal 1, terminal 2, terminal 3 and terminal 4 perform network synchronization respectively based on the synchronization signal of terminal 0, and send the synchronization signal in the synchronization channel, wherein the synchronization source period is 320 ms.

When the number of other synchronization signals detected by the terminal 0 and the RSRP value of the synchronization signal is greater than the threshold value is 2, the terminal 0 adjusts the synchronization period to be 640 ms.

And the other terminals carry out synchronization based on the synchronization signals and send the synchronization signals, and the sending period can be determined according to the number of the detected synchronization sources of which the RSRP is greater than the threshold value. And the terminal which has sent the synchronous signal adjusts the period of sending the synchronous signal according to the number of the detected RSRP larger than the threshold value.

In one embodiment, the network has 16 terminals, and the configured synchronization signal sending trigger mode determines whether to send synchronization information according to RSRP and Timing Advance (TA) for all terminals.

When initially establishing a network, the terminal 0 is started at the earliest, and through synchronous source detection, if no synchronous source is detected within a period of time, a synchronous channel is randomly selected based on local timing to send a synchronous signal, wherein the period is 320 ms.

The subsequent terminal 1, terminal 2, terminal 3, and terminal 4 perform network synchronization based on the synchronization signal of terminal 0, respectively. The terminal 1 and the terminal 2 are very close to the synchronous source 0, and do not send the synchronous signal according to the triggering condition; the terminal 3 and the terminal 4 are far from the synchronization source and transmit the synchronization signal according to the trigger condition.

And the terminal 0 detects the terminal 3 and the terminal 4, and the synchronization source RSRP of the terminal 3 is greater than the threshold value, and the synchronization period maintained by the terminal 0 is 320 ms.

And the other terminals carry out synchronization based on the synchronization source, judge whether to send the synchronization signal according to the synchronization signal triggering condition, and if the synchronization signal is sent, the sending period is determined according to the number of the detected synchronization sources of which the RSRP is greater than the threshold value. And the terminal which has sent the synchronization signal adaptively adjusts the period for sending the synchronization signal according to the number of the detected homologous sources of which the RSRP is larger than the threshold value.

S40: and when any terminal to be synchronized is judged to send the synchronization signal, adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal.

In this embodiment, when it is determined that any terminal to be synchronized transmits a synchronization signal, the transmission period of the synchronization signal is adjusted according to the number of detected synchronization signals and/or the energy value of the synchronization signal. The transmission period of the synchronization signal can be adaptively adjusted in combination with the detected signal quality of the synchronization source. Determining the sending period of the synchronous signal based on the detected number of the synchronous source IDs and the signal quality, and the following table shows that:

it can be understood that the specific parameter configuration (including synchronization period, synchronization interval, number of detected synchronization sources, and threshold) in the table does not affect the application of the present solution.

In one embodiment, the adjusting the transmission period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal includes:

when the number of the synchronous signals detected by the terminal to be synchronized is larger than the preset number, increasing the sending period of the synchronous signals;

and when the number of the synchronous signals detected by the terminal to be synchronized is less than or equal to the preset number, reducing the sending period of the synchronous signals.

When the number of the detected synchronous signals is large, the sending period of the synchronous signals can be increased so as to meet the access of more users; when the number of detected synchronization signals is small, the sending period can be varied to reduce the user access delay, and the specific number of the synchronization signals is shown in the table.

For example, the sync channel interval is 160ms, there are 2 sync channels in a period of 320ms, and there are 16 sync channels in a maximum period of 2.56 s.

In one embodiment, the method further comprises:

and the adjacent terminal corresponding to the terminal to be synchronized which sends the synchronization signal carries out timing synchronization according to the synchronization signal. For example, the terminal to be synchronized includes a terminal a, and the terminals adjacent to the terminal a include a terminal B and a terminal C, and the terminal B and the terminal C perform timing synchronization according to the synchronization signal sent by the terminal a.

Fig. 3 is a schematic diagram of a network timing synchronization system structure based on an ad hoc network according to the present invention. The network timing synchronization system based on the ad hoc network comprises:

an adjusting unit: and the method is used for adjusting the sending period of the synchronous signals according to the number of the detected synchronous signals and/or the energy value of the synchronous signals when the terminal to be synchronized sends the synchronous signals.

In one embodiment, the system further includes a condition determining unit for the terminal to be synchronized to send a synchronization signal:

the method comprises the steps that when any terminal in the ad hoc network sends a synchronization signal, at least one terminal to be synchronized of the ad hoc network detects the synchronization signal in a synchronization channel and acquires attribute information of the synchronization signal;

the terminal to be synchronized performs timing synchronization with the synchronization signal based on the power value and/or the energy value in the attribute information;

the terminal to be synchronized judges whether to send the synchronization signal or not based on a preset trigger condition of the synchronization signal;

and when any terminal to be synchronized is judged to send the synchronization signal, adjusting the sending period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal.

In one embodiment, the system further comprises a synchronization unit for:

and the adjacent terminal corresponding to the terminal to be synchronized which sends the synchronization signal carries out timing synchronization according to the synchronization signal.

In one embodiment, the performing timing synchronization with a synchronization signal by the terminal to be synchronized based on the power value and/or the energy value in the attribute information includes:

a terminal to be synchronized acquires timing information from a synchronization signal to the local and sends access information to a sending terminal corresponding to the synchronization signal in an access channel;

a sending terminal corresponding to the synchronization signal sends a random access response to a terminal to be synchronized;

and the terminal to be synchronized acquires the random access response and acquires the ad hoc network timing information and/or the timing information of the local synchronization signal.

In one embodiment, the determining, by the terminal to be synchronized, whether to send the synchronization signal based on a preset trigger condition of the synchronization signal includes:

the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal, and when the energy value is smaller than a first preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or, the terminal to be synchronized searches for the synchronization signal, receives the timing adjustment value of the synchronization signal, and when the timing adjustment value is greater than or equal to a second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or, the terminal to be synchronized searches for the synchronization signal, measures the energy value of the synchronization signal and receives the timing adjustment value of the synchronization signal, when the energy value is smaller than the first preset value or the timing adjustment value is larger than or equal to the second preset value, the terminal to be synchronized sends the synchronization signal, otherwise, the terminal does not send the synchronization signal;

or all the terminals to be synchronized transmit the synchronization signal.

In one embodiment, the adjusting the transmission period of the synchronization signal according to the number of the detected synchronization signals and/or the energy value of the synchronization signal includes:

when the number of the synchronous signals detected by the terminal to be synchronized is larger than the preset number, increasing the sending period of the synchronous signals;

and when the number of the synchronous signals detected by the terminal to be synchronized is less than or equal to the preset number, reducing the sending period of the synchronous signals.

In one embodiment, the attribute information of the synchronization signal further includes: the method comprises the steps of identifying the ID of a synchronous signal, the time slot number of the synchronous signal and the period indication of the synchronous signal, wherein the ID of the synchronous signal comprises the physical layer ID or partial physical layer ID of a user, and the period indication is used for indicating the period of the terminal for sending the synchronous signal.

The specific implementation of the network timing synchronization system based on ad hoc network of the present invention is substantially the same as the specific implementation of the network timing synchronization method based on ad hoc network, and will not be described herein again.

It should be noted that the above-mentioned numbers of the embodiments of the present invention are merely for description, and do not represent the merits of the embodiments. And the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, apparatus, article, or method. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, apparatus, article, or method that includes the element.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.