TW201640858A - Synchronization source device for synchronization coverage extension and method and system using the same - Google Patents

Abstract

A synchronization source device includes a receiving circuit, a timing adjusting circuit and a transmitting circuit. The receiving circuit receives a first synchronization signal from a evolved node B (eNB). The timing adjusting circuit, in response to the first synchronization signal, adjusts the timing for transmitting a second synchronization signal according to a timing indicator, wherein the timing of the second synchronization signal corresponds to that of the first synchronization signal. The transmitting circuit transmits the timing indicator, and sending the second synchronization signal based on the adjusted timing.

Description

Signal synchronization source device for extending synchronization signal coverage and communication method thereof Communication system

The disclosure relates to a signal synchronization source device capable of extending the coverage of a synchronous signal, a communication method thereof and a communication system.

How to effectively synchronize the clocks of multiple devices has always been an issue to be solved in communication. According to the current communication specifications, the synchronization clock of the Evolved Node B (eNB) can be extended to other devices via the transmission of the signal synchronization source device. However, when a device simultaneously receives a plurality of synchronization signals from different signal synchronization source devices, the synchronization signals may collide and cause unreadable, so that the device cannot synchronize with the eNB.

Therefore, how to propose a communication technology that can reduce the probability of collision of synchronous signals is one of the topics that the industry is currently working on.

The disclosure relates to a signal synchronization source device, a communication method thereof and a communication system, which can effectively make different signal synchronization source devices stagger their transmission synchronization. The timing of the signal to reduce the probability of the sync signal colliding on other devices, thereby extending the synchronization signal coverage of the eNB.

According to an embodiment of the present disclosure, a signal synchronization source device is provided. The signal synchronization source device includes a receiving circuit, a timing adjustment circuit, and a transmitting circuit. The receiving circuit receives the first synchronization signal from the Evolved Node B (eNB). The timing adjustment circuit responds to the first synchronization signal, and adjusts the timing of transmitting the second synchronization signal according to the timing indicator, wherein the clock of the second synchronization signal corresponds to the clock of the first synchronization signal. The transmitting circuit sends the timing indicator, and sends the second synchronization signal according to the adjusted timing of the timing indicator.

According to an embodiment of the present disclosure, a communication method of a signal synchronization source device is provided. The communication method includes the following steps: receiving a first synchronization signal from an eNB; and adjusting a timing of transmitting a second synchronization signal according to the first synchronization signal and a timing indicator, The different values of the timing indicator correspond to at least two different transmission timings of the second synchronization signal; and the transmission timing indicator, and the second synchronization signal is sent according to the adjusted timing of the timing indicator.

According to an embodiment of the present disclosure, a communication system is provided, which includes an eNB, a first signal synchronization source device, a second signal synchronization source device, and a remote user device. The eNB sends the first synchronization signal. The first signal synchronization source device receives the first synchronization signal from the eNB and is assigned a first timing indicator, and the first signal synchronization source device adjusts the timing of transmitting the second synchronization signal according to the first timing indicator, and adjusts the timing. Sending a second synchronization signal and a first timing indicator, wherein a clock of the second synchronization signal corresponds to a clock of the first synchronization signal. Second signal synchronization source device from eNB Receiving the first synchronization signal and assigning a second timing indicator, the second signal synchronization source device adjusts the timing of transmitting another second synchronization signal according to the second timing indicator, and transmits another second synchronization signal at the adjusted timing And a second timing indicator, wherein the clock of the other second synchronization signal corresponds to the clock of the first synchronization signal. The remote user device receives the second synchronization signal, another second synchronization signal, the first timing indicator, and the second timing indicator, and restores the timing of the second synchronization signal according to the first timing indicator, and according to the second timing indicator. The timing of the other second synchronization signal is restored to obtain a clock corresponding to the first synchronization signal.

In order to better understand the above and other aspects of the present disclosure, the preferred embodiments are described below in detail with reference to the accompanying drawings.

100, 500, 600‧‧‧ communication systems

102, 502, 602‧‧‧ eNB

104‧‧‧First signal synchronization source device

106‧‧‧Second signal synchronization source device

108, 508, 608, 700, 806‧‧‧ remote user devices

SS1‧‧‧First sync signal

SS2, SS2'‧‧‧ second synchronization signal

Tind1‧‧‧ first time series indicator

Tind2‧‧‧Second time series indicator

Tind1’‧‧‧ updated first time series indicator

Tind2’‧‧‧ second timing indicator after update

200, 504, 506, 510, 604, 606, 610, 802, 804‧‧‧ signal synchronization source device

202‧‧‧ receiving circuit

204‧‧‧ Timing adjustment circuit

206‧‧‧Transmission circuit

302, 304, 306, 304', 306', 1002, 1004‧‧ ‧ timing

T1, T2‧‧ cycle

T0‧‧‧

Tost1, Tost2‧‧‧ delay time

NULL‧‧‧ null

400‧‧‧D2D sync subframe

S51a, S51b, S52, S53a, S53b, S54, S61a, S61b, S62, S63a, S63b, S64, S81, S82a, S82b, S83a, S83b, S91, S92, S93‧‧

702‧‧‧ collision detection circuit

704‧‧‧ Timing selection circuit

Cind‧‧‧ Collision indicator

PD2DSS‧‧‧Master device to device synchronization signal

SD2DSS1, SD2DSS2, SD2DSS‧‧‧ device-to-device synchronization signals

DMRS‧‧‧ demodulation reference signal

PD2DSCH‧‧‧ physical device pair device synchronization channel

GAP‧‧ ‧ interval

FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present disclosure.

FIG. 2 is a block diagram of a signal synchronization source device according to an embodiment of the present disclosure.

FIG. 3A and FIG. 3B are diagrams showing transmission timings corresponding to two exemplary timing indicators for transmitting the second synchronization signal by the first and second signal synchronization source devices in FIG. 1 .

FIG. 4 is a schematic diagram showing the implementation of the second synchronization signal by the content of the D2D synchronization sub-frame.

FIG. 5 is a flow chart showing a communication method of a communication system according to an embodiment of the present disclosure.

FIG. 6 is a flow chart showing a communication method of a communication system according to an embodiment of the present disclosure.

FIG. 7 is a block diagram of a remote user device in accordance with an embodiment of the present disclosure.

FIG. 8 is a flow chart showing a communication method using a collision indicator according to an embodiment of the present disclosure.

FIG. 9 is a flow chart showing an example of detecting whether a second synchronization signal collides according to an embodiment of the present disclosure.

FIG. 10 is a timing diagram showing the signal of the collision of the second synchronization signal.

In the present description, some embodiments of the invention are described in detail with reference to the drawings, but not all embodiments are illustrated in the drawings. In fact, these inventions may use a variety of different variations and are not limited to the embodiments herein. In contrast, the present disclosure provides these embodiments to meet the statutory requirements of the application. The same reference symbols are used in the drawings to refer to the same or similar elements.

FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present disclosure. As shown in FIG. 1, the communication system 100 includes an Evolved Node B (eNB) 102, a plurality of signal synchronization source devices, such as a first signal synchronization source device 104, a second signal synchronization source device 106, and a remote end. User device 108. The signal synchronization source device is, for example, a user device, and can be used as an independent signal synchronization source or a dependent signal synchronization source depending on network conditions. When used as an independent signal synchronization source, the device can send a synchronization signal corresponding to its own clock. When acting as a dependent signal synchronization source, the device can transmit the clock and its corresponding synchronization signal in response to the synchronization signal from the outside.

The eNB 102 can transmit the first synchronization signal SS1 to synchronize the clocks of other devices. The first synchronization signal SS1 includes, for example, a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS).

Generally, when the first synchronization signal SS1 sent from the eNB 102 is sent to multiple signal synchronization source devices, the signal synchronization source devices will serve as the dependent signal synchronization source, and respond to the first synchronization signal SS1 almost simultaneously. Send the second sync signal (such as SS2/SS2') to other devices. However, this mechanism will increase the probability that a second sync signal (e.g., SS2/SS2') will collide on other receiving devices. Therefore, in the disclosed embodiment, the signal synchronization source device will use timing indicators to adjust the timing of transmitting the second synchronization signal (such as SS2/SS2') to prevent multiple signal synchronization source devices from transmitting at the same time. Synchronous signals (such as SS2/SS2') cause signal collisions. In this manner, remote user devices located outside the signal coverage (or edge) of the eNB 102 signal or within the signal coverage of the signal coverage can be indirectly synchronized with the eNB 102 to effectively extend the eNB 102. Synchronous signal coverage.

As shown in FIG. 1, the first signal synchronization source device 104 receives the first synchronization signal SS1 from the eNB 102 and is assigned the first timing indicator Tind1. The first signal synchronization source device 104 adjusts the timing of transmitting the second synchronization signal SS2 according to the first timing indicator Tind1, and transmits the second synchronization signal SS2 and the first timing indicator Tind1 at the adjusted timing. The clock of the second synchronization signal SS2 corresponds to the clock of the first synchronization signal SS1.

On the other hand, the second signal synchronization source device 106 is connected from the eNB 102. The first synchronization signal SS1 is received and assigned to the second timing indicator Tind2. The second signal synchronization source device 106 adjusts the timing of transmitting another second synchronization signal SS2' according to the second timing indicator Tind2, and transmits the other second synchronization signal SS2' and the second timing indicator Tind2 at the adjusted timing. The clock of the other second synchronization signal SS2' corresponds to the clock of the first synchronization signal SS1.

The first timing indicator Tind1 and the second timing indicator Tind2 are, for example, such that the timing at which the first signal synchronization source device 104 transmits the second synchronization signal SS2 is shifted from the timing at which the second signal synchronization source device 106 transmits another second synchronization signal SS2'. .

The remote user device 108 receives the second synchronization signal SS2 from the first signal synchronization source device 104, another second synchronization signal SS2' from the second signal synchronization source device 106, the first timing indicator Tind1, and the second timing. The indicator Tind2 is used to restore the timing of the second synchronization signal SS2 according to the first timing indicator Tind1, and restore the timing of the second synchronization signal SS2' according to the second timing indicator Tind2 to obtain the clock corresponding to the first synchronization signal SS1. .

In the example of FIG. 1, the remote user device 108 is, for example, located outside the signal coverage (or edge of the range) of the eNB 102, or is obscured by an obstacle and cannot directly receive the first synchronization signal SS1 from the eNB 102. Device. The remote user device 108 can indirectly obtain the synchronization clock of the eNB 102 and synchronize with it by the second synchronization signal (e.g., SS2/SS2') transmitted by the other source synchronization source devices (e.g., 104, 106). Since the transmission timing of the second synchronization signal (such as SS2/SS2') from different signal synchronization source devices is shifted by the timing indicator, the remote user device 108 can be successfully detected to detect the second synchronization signal (SS2/). SS2') and synchronize The probability of the OFDM 102's synchronization signal coverage is effectively extended. After the remote user device 108 indirectly obtains and synchronizes with the synchronization clock of the eNB 102, the remote user device 108 can become a dependent signal synchronization source device, and then send a synchronization signal to continuously extend the synchronization of the eNB 102. Signal coverage.

FIG. 2 is a block diagram of a signal synchronization source device according to an embodiment of the present disclosure. As shown in FIG. 2, the signal synchronization source device 200 includes a receiving circuit 202, a timing adjustment circuit 204, and a transmitting circuit 206. Receive circuitry 202 includes, for example, a wireless signal receiver. The receiving circuit 202 can receive the first synchronization signal (such as SS1) from the eNB. By detecting the first synchronization signal, the signal synchronization source device 200 can obtain the reference clock of the eNB, and then parse the control signal and/or other information sent by the eNB.

The timing adjustment circuit 204 can respond to the first synchronization signal, and adjust the timing of transmitting the second synchronization signal (such as SS2/SS2' in FIG. 1) according to the timing indicator (such as Tind1/Tind2 in FIG. 1), wherein the second synchronization signal The clock system corresponds to the clock of the first synchronization signal. For example, there is a specific phase difference between the second synchronization signal and the first synchronization signal.

In the disclosed embodiment, the different values of the timing indicators correspond to at least two different timings for transmitting the second synchronization signal. For example, the timing adjustment circuit 204 can (1) adjust a time delay amount for transmitting the second synchronization signal according to the timing indicator, and/or (2) determine, according to the timing indicator, whether to send the second synchronization signal in a synchronization signal transmission period. . Timing adjustment circuit 204 can be implemented, for example, in a particular purpose application circuit, processor, or other operational circuit.

The transmitting circuit 206 includes, for example, a wireless transmitter that can transmit timing indicators and transmit a second synchronization signal (such as SS2/SS2' in FIG. 1) according to the timing adjusted by the timing indicator. Sending the timing indicator together with the second synchronization signal (such as Tind1/Tind2 in FIG. 1) allows the receiving device (such as the remote user device 108 in FIG. 1) to restore the original timing of the corresponding second synchronization signal according to the timing indicator. And then synchronized with the clock of the eNB.

3A and 3B are diagrams showing transmission timings corresponding to two exemplary timing indexes for transmitting the second synchronization signals SS2 and SS2' by the first and second signal synchronization source devices 104 and 106 of Fig. 1. In FIG. 3A, timing 302 represents the timing at which eNB 102 transmits a first synchronization signal SS1 (eg, PSS/SSS) with a transmission period of T1 (eg, 5 milliseconds). The timings 304 and 306 respectively represent the timings at which the first and second synchronization source devices 104, 106 transmit the second synchronization signals SS2, SS2', and the transmission period is T2 (e.g., 40 milliseconds).

In the example of Fig. 3A, the timing indicator Tind1/Tind2 is used to indicate the amount of time delay for transmitting the second synchronization signal SS2/SS2'. Further, if the signal synchronization source device that does not use the timing indicator responds to the first synchronization signal (such as PSS/SSS) of the eNB and the start time of the second synchronization signal is t0, the signal synchronization source device in this embodiment is based on the timing. The index Tind1/Tind2 delays the start time of transmitting the second synchronization signal SS2/SS2' from time t0 by a specific time.

As shown in the sequence 304, the first signal synchronization source device 104 delays the start time of the second synchronization signal SS2 from the time point t0 to the delay time Tost1 according to the time delay amount indicated by the timing indicator Tind1. Similarly, as shown in timing 306, the second synchronization source device 106 is based on the time indicated by the timing indicator Tind2. The delay amount, the start time of the second synchronization signal SS2' is transmitted from the time point t0 to the delay time Tost2. Therefore, if the values of the first and second timing indicators Tind1 and Tind2 are appropriately selected such that the delay times Tost1 and the length of the Tost2 are different, the first and second synchronization source devices 104 and 106 can be shifted to send the second synchronization in response to the first synchronization signal SS1. The timing of the signals SS2, SS2' to avoid sync signal collisions on the receiving device (such as the remote user device 108 of Figure 1).

In the example of FIG. 3B, the first signal synchronization source device 104 selectively transmits the second synchronization signal SS2 or provides a null value NULL in the synchronization signal transmission period T2 according to the first timing indicator Tind1, and the second signal synchronization source The device 106 selectively provides a null value NULL or a second synchronization signal SS2' in the synchronization signal transmission period T2 according to the second timing indicator Tind2. As shown by timings 304' and 306', when the first signal synchronization source device 104 selects to transmit the second synchronization signal SS2, the second signal synchronization source device 106 provides a null value NULL. On the contrary, when the first signal synchronization source device 104 selects to provide the null value NULL, the second signal synchronization source device 106 transmits the second synchronization signal SS2'. The null value NULL can be implemented by any means that the second synchronization signal SS2/SS2' is not transmitted, such as not transmitting a message, or transmitting information of an asynchronous signal, or the like.

FIG. 4 is a schematic diagram showing the implementation of the second synchronization signal by the content of the device-to-device (D2D) synchronization sub-frame 400. The D2D synchronization sub-frame 400 includes two primary device-to-device synchronization signals (PD2DSS) symbols and two secondary device-to-device synchronization signals (Secondary Device-to-Device). Synchronization Signal, SD2DSS) code, 2 Demodulation Reference Signal (DMRS) symbols, 1 interval (GAP) code, and 7 physical device-to-device synchronization channels (Physical Device-to- The code of Device Synchronization Channel, PD2DSCH). In an embodiment, the second synchronization signal sent by the signal synchronization source device is implemented by a D2DSS, wherein the D2DSS is defined by the PD2DSS and the SD2DSS. That is to say, the second synchronization signal includes PD2DSS and SD2DSS.

For the D2DSS (also called D2DSSue_net) sent by the signal synchronization source device that directly receives the synchronization reference clock from the eNB, the code of the PD2DSS has the same root value (for example, root = "26"). In contrast, for the D2DSS (also referred to as D2DSSue_oon) sent by the signal synchronization source device that does not receive the synchronization reference clock from the eNB, the code of the PD2DSS corresponds to another value (for example, root=“37”). The SD2DSS corresponds to the identification code (Identifier, ID) of the signal synchronization source device, so the SD2DSS transmitted by the different signal synchronization source devices corresponds to different signal values. The PD2DSCH can carry control messages. In an embodiment, the timing indicator is included, for example, in the PD2DSCH field placed in the D2D sync subframe 400.

FIG. 5 is a flow chart of a communication method of the communication system 500 according to an embodiment of the present disclosure. In FIG. 5, the communication system 500 includes an eNB 502, signal synchronization source devices 504, 506, and 510, and a remote user device 508. The signal synchronization source devices 504 and 506 are directly within the signal coverage of the eNB 502. The reference clock is received from the eNB 502; the signal synchronization source device 510 and the remote user device 508 are, for example, located outside the signal coverage of the eNB 502 (or the edge signal micro The weak point), or signal masking within the coverage of the eNB 502 signal, cannot receive the reference clock directly from the eNB 502.

In steps S51a and S51b, the eNB 502 transmits the first synchronization signal SS1 (such as PSS/SSS) to the signal synchronization source devices 504 and 506, and distributes the timing indicators Tind1 and Tind2 for the signal synchronization source devices 504 and 506, respectively. The timing indicator Tind1/Tind2 is included, for example, in a control signal transmitted from the eNB 502, such as a System Information Block (SIB), a Radio Resource Control (RRC), or other control signals/messages. In an embodiment, the eNB 502 may plan to generate values for the timing indicators Tind1 and/or Tind2. For example, the eNB 502 can determine the values of the timing indicators Tind1 and Tind2 according to the locations of the signal synchronization source devices 504 and 506. However, the disclosure is not limited thereto, and the eNB 502 may also plan the timing indicator Tind1/Tind2 value according to the network environment and/or device distribution status. In yet another embodiment, the values of the timing indicators are randomly generated by the eNB.

In step S52, the signal synchronization source device 510, for example, as an independent signal synchronization source, externally transmits an independent synchronization signal SS3 (such as D2DSSue_oon) based on its own clock. In some embodiments, the communication system 500 may not include an independent signal synchronization source, that is, the signal synchronization source device 510 is not included, in which case step S52 may be omitted.

In steps S53a and S53b, the signal synchronization source devices 504 and 506 respectively transmit the second synchronization signals SS2, SS2' (eg, D2DSSue_net) and the timing indicators Tind1, Tind2 to the remote end according to the adjusted timing indicated by the timing indicators Tind1 and Tind2, respectively. Device 508.

In step S54, the remote user device 508 receives the reference signal according to the priority order of all received synchronization signals (for example, the second synchronization signal SS2, SS2' and the third synchronization signal SS3 (if any) and the signal strength thereof. The Reference Signal Received Power (RSRP) measurement value selects the best synchronization reference clock and correspondingly changes the user type (UE Type). For example, when the remote user device 508 initially receives only the synchronization signal sent by the OM 502 out-of-coverage signal synchronization source device 510, the remote user device 508 The synchronization signal of the signal synchronization source device 510 is selected as the synchronization reference clock, and the user device type is the UE synchronized with the synchronization signal outside the signal coverage. When the signal synchronization source device 508 later selects the synchronization signal transmitted in the signal coverage range and corresponds to the signal synchronization source device of the larger RSRP as the reference clock, the user device type correspondingly changes to be synchronized with the eNB 502 synchronization signal coverage. In-coverage UE that synchronizes signals.

Since the second synchronization signal SS2/SS2' received by the remote user device 508 from the synchronization source devices 504 and 506 is likely to be transmitted at a staggered timing, the remote user device 508 can correctly detect the two. The second synchronization signal SS2/SS2' is followed by a subsequent operation (such as step S54) to select a synchronization clock. Through the above mechanism, the synchronization signal coverage of the eNB 502 can be extended to the remote user device 508.

FIG. 6 is a flow chart showing a communication method of the communication system 600 according to an embodiment of the present disclosure. Similar to FIG. 5, in FIG. 6, the communication system 600 includes an eNB 602, signal synchronization source devices 604, 606, and 610, and a remote user device. The signal synchronization source device 604, 606 is located within the signal coverage of the eNB 602, and can receive the reference clock directly from the eNB 602. The signal synchronization source device 610 and the remote user device 608 are, for example, located at the eNB 602. The signal is out of coverage (or the edge signal is weak) or is in the signal mask within the coverage of the eNB 602 signal, which cannot receive the reference clock directly from the eNB 602.

In this embodiment, the value of the timing indicator is randomly generated by the signal synchronization source device. As shown in FIG. 6, in steps S61a and S61b, the eNB 602 transmits the first synchronization signal SS1 (e.g., PSS/SSS) to the signal synchronization source devices 604 and 606 within its signal coverage.

In step S62, the signal synchronization source device 610, for example, as an independent signal synchronization source, externally transmits an independent synchronization signal SS3 (such as D2DSSue_oon) based on its own clock. In some embodiments, the communication system 600 may not include an independent signal synchronization source, that is, the signal synchronization source device 610 is not included, in which case step S62 may be omitted.

In steps S63a and S63b, the signal synchronization source devices 604 and 606 randomly generate the values of the timing indicators Tind1 and Tind2, respectively, and adjust the timing of transmitting the second synchronization signals SS2 and SS2' (such as D2DSSue_net), the second synchronization signal SS2. The SS2' and the corresponding timing indicators Tind1, Tind2 are sent to a device that cannot receive the synchronization clock directly from the eNB 602, such as the remote user device 608.

Step S64 is similar to step S54 of FIG. 5, and the remote user device 608 will prioritize all received synchronization signals (eg, the second synchronization signal SS2, SS2' and the third synchronization signal SS3 (if any)). And its signal strength The RSRP measurement value selects the best synchronization reference clock and corresponds to the type of user device that changes itself. Since the transmission timing of the second synchronization signal SS2/SS2' is randomly determined, the probability of collision between the two can be greatly reduced.

FIG. 7 is a block diagram of a remote user device 700 in accordance with an embodiment of the present disclosure. The remote user device 700 includes a timing selection circuit 704 that can determine the optimal synchronization reference clock. At the same time, the remote user device 700 further includes a collision detection circuit 702, which can determine whether the received synchronization signal collides, and send the collision index Cind through the transmission circuit 206 after detecting the collision. The collision indicator Cind is used to enable another signal synchronization source device that sends the synchronization signal to update the timing of transmitting the synchronization signal.

For example, when the remote user device 700 detects that the received multiple synchronization signals collide, the collision indicator Cind is broadcasted to indicate that the multiple signal synchronization source devices that send the synchronization signals re-adjust the transmission timing. To reduce the chance of a recurring signal collision.

FIG. 8 is a flow chart showing a communication method using the collision index Cind according to an embodiment of the present disclosure. As shown in FIG. 8, in step S81, after detecting that the received synchronization signal collides, the remote user device 806 sends the collision index Cind to the outside, as shown in steps S82a and S82b. The collision indicator Cind may be included in, for example, a PD2DSCH field placed in the D2D synchronization subframe 400. Next, in steps S83a and S83b, when the signal synchronization source devices 802, 804 receive the collision index Cind, the response index Cind updates the timing indicators Tind1, Tind2, and updates the second synchronization according to the updated timing indicators Tind1', Tind2'. News The transmission timings of the numbers SS2 and SS2' are retransmitted with the updated timings of the second synchronization signals SS2 and SS2' and the updated timing indicators Tind1' and Tind2'. Therefore, even if the signal synchronization source devices 802 and 804 transmit the second synchronization signals SS2 and SS2′ according to the original timing indicators Tind1 and Tind2, and still collide (for example, all of the same timing index values are randomly selected), the signal synchronization source devices 802 and 804 still The transmission timing of the second synchronization signals SS2 and SS2' can be corrected by the collision index Cind fed back by the receiving device (for example, the remote user device 806) to avoid re-signal collision.

It can be understood that the collision detection and retransmission mechanism shown in FIG. 8 can be applied to various embodiments of the present disclosure. As shown in FIG. 5, if the second synchronization signals SS2, SS2' sent by the signal synchronization source devices 504, 506 still collide with the remote user device 508, the remote user device 508 can perform as shown in FIG. The step of causing the signal synchronization source devices 504, 506 to update the timing indicators Tind1, Tind2 through the collision index Cind and perform retransmission. The flow of Fig. 8 can be repeatedly executed until the synchronization signal collision condition is released, and then step S54 is executed to determine the synchronization reference clock. Similarly, in FIG. 6 , if the second synchronization signals SS2 and SS2 transmitted by the signal synchronization source devices 604 and 606 still collide with the remote user device 608, the remote user device 608 can perform the eighth process. The steps shown in the figure cause the signal synchronization source devices 604, 606 to update the timing indicators Tind1, Tind2 and retransmit them by the collision index Cind. The flow of Fig. 8 can be repeatedly executed until the synchronization signal collision condition is released, and then step S64 is executed to determine the synchronization reference clock.

Please refer to Figure 9 and Figure 10. FIG. 9 is a flow chart showing an example of detecting whether a collision occurs between the second synchronization signal SS2/SS2' according to an embodiment of the present disclosure. Figure. Fig. 10 is a timing chart showing the collision of the second synchronizing signals SS2 and SS2'. In this embodiment, the second synchronization signal SS2/SS2' is described as D2DSS.

As described above, for the D2DSS sent by different signal synchronization source devices receiving the eNB reference clock, the PD2DSS has the same value, and the SD2DSS corresponds to different values because of the ID of the corresponding signal source. With this feature, when receiving D2DSS from different signal synchronization source devices, as long as the PD2DSS can be detected but the SD2DSS cannot be solved, the synchronization signal collision can be determined. Even if the PD2DSS cannot be solved, it can be determined that the synchronization signal has not been received.

As shown in step S91, the PD2DSS and the SD2DSS in the received signal are detected. Next, in step S92, it is determined whether the PD2DSS is detected. If yes, proceed to step S93. If not, it is determined that the synchronization signal has not been received.

In step S93, it is determined whether the SD2DSS cannot be detected or more than one SD2DSS is detected. If it is, it means that the detection result is wrong, that is, the signal collides. On the contrary, it can be judged that no collision has occurred. As shown in Fig. 10, timings 1002 and 1004 represent timings at which the two signal synchronization source devices respectively transmit the second synchronization signals SS2 and SS2'. When the timing indexes of the two synchronization signals are the same, the two synchronization signals have a timing collision. At this time, since the two signal synchronization source devices receive the reference clock of the eNB, for example, the PD2DSS of the second synchronization signal SS2/SS2' are the same. Since the collision of the same signal is only superimposed, the receiver can still solve the PD2DSS.

On the other hand, since the second synchronization signals SS2 and SS2' are respectively The same signal synchronization source device transmits, so the corresponding SD2DSS system is different (SD2DSS1 and SD2DSS2 as shown in the figure). Therefore, when the signal collides, it will not be able to detect the SD2DSS in the second sync signal SS2/SS2' or detect more than one SD2DSS error result. In general, if both the condition of (1) detecting PD2DSS and (2) detecting SD2DSS/detecting more than one SD2DSS are satisfied, it can be judged that the synchronization signal collides.

In summary, the signal synchronization source device and the communication method and the communication system thereof are provided. The signal synchronization source device can adjust the timing of transmitting the synchronization signal according to the timing indicator, and can also update the transmission synchronization signal when the collision indicator is received. The timing is to avoid the collision of the synchronization signal, thereby extending the coverage of the synchronization signal of the eNB.

Although the disclosure has been disclosed above in the preferred embodiments, it is not intended to limit the disclosure. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure. Therefore, the scope of protection of this disclosure is subject to the definition of the scope of the appended claims.

200‧‧‧Signal sync source device

202‧‧‧ receiving circuit

204‧‧‧ Timing adjustment circuit

206‧‧‧Transmission circuit

Claims (32)

A signal synchronization source device includes: a receiving circuit that receives a first synchronization signal from an Evolved Node B (eNB); a timing adjustment circuit that responds to the first synchronization signal and adjusts the transmission according to a timing indicator The timing of the second synchronization signal, the clock of the second synchronization signal corresponds to the clock of the first synchronization signal; and a transmitting circuit that transmits the timing indicator and transmits the second synchronization according to the adjusted timing of the timing indicator Signal. The signal synchronization source device of claim 1, wherein the timing indicator is included in a control signal sent from the evolved Node B. The signal synchronization source device of claim 2, wherein the value of the timing indicator is determined by the evolved Node B according to the location of the signal synchronization source device. The signal synchronization source device of claim 2, wherein the value of the timing indicator is randomly generated by the evolved Node B. The signal synchronization source device of claim 1, wherein the value of the timing indicator is randomly generated by the signal synchronization source device. The signal synchronization source device according to claim 1, wherein the timing indicator is included in a physical device-to-device synchronization channel (Physical) placed in a Device-to-Device (D2D) synchronization subframe. Device-to-Device Synchronization Channel, PD2DSCH) field. The signal synchronization source device of claim 1, wherein the timing adjustment circuit adjusts a time delay amount for transmitting the second synchronization signal according to the timing indicator. The signal synchronization source device of claim 1, wherein the timing adjustment circuit determines whether to transmit the second synchronization signal in a synchronization signal transmission period according to the timing indicator. The signal synchronization source device of claim 1, wherein when the signal synchronization source device receives a collision indicator, the collision indicator is updated to update the timing indicator, and the second is updated according to the updated timing indicator. The synchronization timing is transmitted, and the second synchronization signal and the updated timing indicator are retransmitted at the updated timing. The signal synchronization source device of claim 9, wherein the collision indicator is sent from a remote user device of one of the second synchronization signal receivers, and the remote user device determines the received second synchronization signal. Whether a collision occurs and the collision indicator is transmitted through the transmitting circuit of the remote user device after detecting the collision. The signal synchronization source device of claim 1, wherein the first synchronization signal comprises a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). The signal synchronization source device of claim 1, wherein the second synchronization signal comprises a Primary Device-to-Device Synchronization Signal (PD2DSS) and a secondary device pair. Secondary Device-to-Device Synchronization Signal (SD2DSS). A communication method for a signal synchronization source device, comprising: receiving a first synchronization signal from an Evolved Node B (eNB); and responding to the first synchronization signal, adjusting a timing of transmitting a second synchronization signal according to a timing indicator The clock of the second synchronization signal corresponds to the clock of the first synchronization signal; and the timing indicator is sent, and the second synchronization signal is sent according to the adjusted timing of the timing indicator. The communication method of claim 13, wherein the timing indicator is included in a control signal sent from the evolved Node B. The communication method of claim 14, further comprising: generating, by the evolved Node B, a value of the timing indicator according to a relative position of the signal synchronization source device and the evolved Node B. The communication method of claim 14, further comprising: randomly generating, by the evolved node B, a value of the timing indicator. The communication method of claim 13, further comprising: randomly generating, by the signal synchronization source device, the value of the timing indicator. The communication method of claim 13, wherein the timing indicator is included in a physical device-to-device synchronization channel (Physical Device-) placed in a Device-to-Device (D2D) synchronization subframe. to-Device Synchronization Channel, PD2DSCH) field. The communication method of claim 13, further comprising: adjusting a time delay amount for transmitting the second synchronization signal according to the timing indicator. For example, the communication method described in claim 13 further includes: determining, according to the timing indicator, whether to send the second synchronization signal in a synchronization signal transmission period. The communication method of claim 13 further includes: when receiving a collision indicator, the collision indicator updates the timing indicator, and updates the transmission timing of the second synchronization signal according to the updated timing indicator; And retransmitting the second synchronization signal and the updated timing indicator with the updated timing. The communication method of claim 21, wherein the collision indicator is sent from a remote user device of one of the second synchronization signal receivers, and the remote user device determines whether the received second synchronization signal collides. And transmitting the collision indicator through the remote user device after detecting the collision. The communication method of claim 13, wherein the first synchronization signal comprises a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). The communication method of claim 13, wherein the second synchronization signal comprises a Primary Device-to-Device Synchronization Signal (PD2DSS) and a Secondary Device-to-Device Synchronization Signal (Secondary Device-to) -Device Synchronization Signal, SD2DSS). A communication system comprising: An Evolved Node B (eNB) transmits a first synchronization signal; a first signal synchronization source device receives the first synchronization signal from the evolved Node B, and is assigned a first timing indicator, The first signal synchronization source device adjusts the timing of transmitting a second synchronization signal according to the first timing indicator, and transmits the second synchronization signal and the first timing indicator, the timing of the second synchronization signal according to the adjusted timing. The pulse corresponds to the clock of the first synchronization signal; a second signal synchronization source device receives the first synchronization signal from the evolved node B, and is assigned a second timing indicator, and the second signal synchronization source device is configured according to the The second timing indicator adjusts a timing of transmitting another second synchronization signal, and transmits the another second synchronization signal and the second timing indicator at an adjusted timing, and the clock of the other second synchronization signal is the first Corresponding to the clock of the synchronization signal; and a remote user device receiving the second synchronization signal, the other second synchronization signal, the first timing indicator, and the second timing indicator, and according to the first timing The timing of the second synchronization signal marked reduction, and the reduction of another second timing synchronization signals according to the second timing indicators to be the first to get the clock synchronization signals. The communication system of claim 25, wherein the first timing indicator and the second timing indicator cause the first signal synchronization source device to transmit the timing of the second synchronization signal and the second signal synchronization source. The timing at which the device transmits the other second synchronization signal is staggered. The communication system of claim 25, wherein the evolved node B is in accordance with the first signal synchronization source device and the second signal synchronization source device. The value of the first timing indicator and the second timing indicator is determined. The communication system of claim 25, wherein the evolved node B randomly determines the first timing indicator and the value of the second timing indicator. The communication system of claim 25, wherein the first signal synchronization source device randomly determines the value of the first timing indicator, and the second signal synchronization source device randomly determines the value of the second timing indicator. The communication system of claim 25, wherein the first signal synchronization source device adjusts a first time delay amount for transmitting the second synchronization signal according to the first timing indicator, and the second signal synchronization source device is based on The second timing indicator adjusts a second time delay amount for transmitting the another second synchronization signal, the first time delay amount being different from the second time delay amount. The communication system of claim 25, wherein the first signal synchronization source device selectively transmits the second synchronization signal or provides a null value in a synchronization signal transmission period according to the first timing indicator. The second signal synchronization source device selectively provides the null value or transmits the another second synchronization signal during the synchronization signal transmission period according to the second timing indicator; wherein when the first signal synchronization source device selects to send the second And synchronizing the signal, the second signal synchronization source device provides the null value; when the first signal synchronization source device selects to provide the null value, the second signal synchronization source device sends the another second synchronization signal. The communication system of claim 25, wherein the remote user device determines whether the second synchronization signal and the another second synchronization signal occur Colliding, and sending a collision indicator after detecting the collision, so that the first signal synchronization source device and the second signal synchronization source device update the timing of transmitting the second synchronization signal and the other second synchronization signal.