CN105634697B

CN105634697B - The configuration method and device of signal parameter in a kind of air interface synchronization

Info

Publication number: CN105634697B
Application number: CN201410613078.0A
Authority: CN
Inventors: 柯颋; 童辉; 王飞; 刘建军; 沈晓冬; 郑毅; 夏亮
Original assignee: China Mobile Communications Group Co Ltd
Current assignee: China Mobile Communications Group Co Ltd
Priority date: 2014-11-04
Filing date: 2014-11-04
Publication date: 2019-05-31
Anticipated expiration: 2034-11-04
Also published as: CN105634697A

Abstract

The present invention provides the configuration methods and device of signal parameter in a kind of air interface synchronization, wherein the configuration method of signal parameter includes: the reference signal configured for same layer source base station as LRS in air interface synchronization, wherein the LRS of same layer source base station is identical；Identical sub-frame offset is configured for the LRS that same layer source base station is sent, the LRS for the source base station transmission of different layers configures different sub-frame offsets；The sub-frame offset for controlling the LRS that each source base station is configured based on itself sends LRS at corresponding subframe position.This programme by for same layer source base station configure identical LRS as reference signal make LRS signal transmitted by same layer source base station each other additivity enhancing to obtaining signal diversifying gain, to solve the synchronous reference signal (LRS transmitted by the multiple source cell of same layer under small cell super-intensive deployment scenario in the prior art, listening RS) because of the problem of being interfered with each other caused by RE resource contention, to improve network air interface synchronization performance.

Description

Method and device for configuring signal parameters in air interface synchronization

Technical Field

The present invention relates to the field of wireless technologies, and in particular, to a method and an apparatus for configuring signal parameters in air interface synchronization.

Background

In order to suppress the inter-station interference, the TDD base stations deployed with the same frequency need to perform inter-station time-frequency synchronization. The 3GPP preferentially supports 3 inter-station time-frequency synchronization schemes: (1) satellite synchronization based on GNSS (Global Navigation Satellite System), such as GPS synchronization; (2) based on ideal backhaul network synchronization, such as IEEE1588v2 synchronization; (3) radio-interface based synchronization (RIBS). In typical application scenarios (such as Home eNodeB, Nano Cell, Small Cell) of LTE such as indoor and high-rise hot spot coverage, GPS signals are not easy to acquire, and ideal backhaul is difficult to guarantee, so that an air interface synchronization technology needs to be researched.

Currently, 3GPP focuses on an air interface synchronization technology called network listening (NW), and the basic principle thereof is as follows: the base station to be synchronized (called target base station or target cell) listens to the synchronization reference signal (LRS) of the synchronized base station (called source base station or source cell), and adjusts the local clock accordingly to maintain the time-frequency synchronization between the stations.

The 3GPP has studied the RIBS technology (radio interface based synchronization) for Home base station (Home eNB) scenarios in the early days, and the basic idea is as follows:

(1) not defining a new listening RS, using the existing reference signal (such as cell common reference signal CRS) as the listening RS, so that the listening RS sequences sent by different source cells are different (scrambled by cell ID);

(2) an eNB (called a target cell) newly accessing a synchronous network selects a certain base station (called a source cell) as a synchronous source of the eNB, namely a target cell only monitors a listening RS of the source cell;

(3) considering a multi-hop synchronization scene, a target cell T1 (synchronization level n) is not set to listen to a CRS of a source cell S1 (synchronization level n-1) at a subframe M for synchronous tracking. T1 may listen to other signals (including LRS or traffic data transmitted by other base stations) besides the LRS transmitted in S1 in the mth subframe, so that the network listening performance is affected, and there are 2 main interference types:

a) interference of downlink signals of the (n + 1) th layer base station on the nth layer interception subframe;

b) interference of downlink signals (possibly LRS) transmitted by base stations except for S1 at layer n-1 to LRS of S1;

(4) for the first kind of interference, 3GPP proposes a cross-subframe muting mechanism to solve;

(5) for the second type of interference, 3GPP has not discussed. review 3GPP documentation from other companies, one potential trending view is: multiple source cells in the same layer transmit respective LRSs in the same downlink subframe, and the LRSs are legacy rss (e.g., CRS, positioning reference signals PRS), so the sequences of the LRSs are different. Obviously, when the number of nodes of the same-layer source cell is small, the LRSs can be staggered in the frequency domain (e.g., by frequency shift technique) to avoid mutual interference of LRS signals of the same layer.

In particular, in the Home eNB and current small cell deployment scenarios, the total number of eNB nodes within one cluster is limited, with a typical value of 8. If the system supports 3 hops, there are 2-3 base stations in each hop (layer). These base stations in the same layer respectively transmit LRS signals (such as CRS or PRS sequences) scrambled by their respective cell IDs on the same subframe, and these LRS signals may be staggered on RE resources through cell planning.

However, for a future more dense deployment scenario of small cells (micro stations) (such as a 5G UDN: ultra dense network), more than 60 small cells may be in a cluster, and more than 7 small cells may be in each hop (layer). If the existing RIBS technology is adopted, that is, the base stations in the same layer respectively transmit the LRS signals scrambled by their respective cell IDs on the same subframe, because the number of source cells in the same layer exceeds the multiplexing degree of the LRS signals (for example, the multiplexing degree of CRS signals of 2 ports is 3, and the multiplexing degree of PRS signals is 6), these LRS signals are difficult to be completely staggered on RE resources even through cell planning, and thus they interfere with each other and reduce the synchronization performance of the network air interface.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method and an apparatus for configuring signal parameters in air interface synchronization, which solve the problem of mutual interference caused by RE resource collision of synchronization reference signals (LRS) sent by multiple source cells on the same layer in a small cell ultra-dense deployment scenario in the prior art.

In order to solve the foregoing technical problem, an embodiment of the present invention provides a method for configuring a signal parameter in air interface synchronization, where the method includes:

configuring a reference signal serving as an LRS for a same-layer source base station, wherein the LRS of the same-layer source base station is the same;

configuring the same subframe offset for the LRS sent by the source base stations at the same layer, and configuring different subframe offsets for the LRS sent by the source base stations at different layers;

and controlling each source base station to send the LRS at the corresponding subframe position based on the subframe offset of the LRS configured by the source base station.

The above configuration method, wherein the configuring the reference signal as the LRS for the same-layer source base station includes:

any one of CRS, PRS and CSI-RS is configured as a reference signal of an LRS of a same-layer source base station, and the same initial phase is configured for the any one of the reference signals.

The above configuration method, wherein the configuring the same initial phase for the arbitrary reference signal includes:

the base station related parameters in the initial phase calculation formula are replaced with the radio frame number to generate the same initial phase.

The invention also provides a method for configuring signal parameters in air interface synchronization, which comprises the following steps:

receiving the same LRS from a plurality of source base stations in the same layer;

acquiring the sending time of a source base station corresponding to each LRS from the LRSs, wherein the sending time of the source base station takes a source base station clock as a reference;

obtaining local receiving time corresponding to a plurality of LRSs when the LRSs arrive, wherein the local receiving time takes a local clock as a reference;

and calculating by using the sending time and the local receiving time of the source base station corresponding to the LRSs to obtain an average timing deviation estimated value.

The foregoing configuration method, wherein before calculating by using the source base station transmission time and local reception time corresponding to each of the LRSs to obtain an average timing deviation estimated value, the method further includes:

obtaining path propagation delay time corresponding to each of the LRSs;

the calculating to obtain the average timing deviation value by using the source base station sending time and the local receiving time corresponding to the LRSs specifically includes:

and calculating by using the sending time, the local receiving time and the path propagation delay time of the source base station corresponding to the LRSs to obtain an average timing deviation value.

configuring an LRS mode for a base station to ensure that the LRS sent by the base station is orthogonal to LRSs sent by other base stations in the same layer;

transmitting the cell-scrambled LRS according to the LRS mode.

In the configuration method, the LRS sent by the base station and LRS sent by other base stations in the same layer are respectively located in GP of different special subframes in the TDD system.

The aforementioned configuration method, wherein the configuring an LRS mode for the base station includes:

sending a signaling for requesting feedback of the used LRS mode to an adjacent base station in the same layer;

receiving response information fed back by the adjacent base station according to the signaling;

and acquiring an LRS mode which is different from LRS modes of all adjacent base stations in a local LRS mode database according to the response information.

determining a candidate subframe of an LRS to be transmitted;

monitoring LRSs sent by other adjacent cells on the candidate subframes;

if the interception result is that the candidate subframe has LRS configuration resources which are not occupied by LRSs of other adjacent cells, determining an unoccupied LRS configuration resource;

and determining an LRS mode according to the determined LRS configuration resource.

The configuration method further includes:

and if the interception result is that all the available LRS configuration resources of the candidate subframe are occupied by the LRSs of the other adjacent cells, continuing to execute the determination of the candidate subframe of the LRS to be sent.

In the above configuration method, in the same cluster, the transmission periods of all LRSs are the same; if the micro station has the switch conversion function, the LRS is also sent even if the micro station is in a dormant state; the LRS has a characteristic point different from other signals and can be identified by other neighboring cells.

The invention also provides a device for configuring signal parameters in air interface synchronization, which comprises:

a first configuration module, configured to configure a reference signal as an LRS for a same-layer source base station, where the LRSs of the same-layer source base station are the same;

a second configuration module, configured to configure the same subframe offset for the LRS sent by the source base stations on the same layer, and configure different subframe offsets for the LRS sent by the source base stations on different layers;

and the control module is used for controlling each source base station to send the LRS at the corresponding subframe position based on the subframe offset of the LRS configured by the source base station.

The above configuration device, wherein the first configuration module comprises:

a first configuration unit, configured to configure any one of a CRS, a PRS, and a CSI-RS as a reference signal of an LRS of a peer source base station;

and the second configuration unit is used for configuring the same initial phase for the arbitrary reference signal.

The above configuration device, wherein the second configuration unit includes:

a replacing component for replacing the base station related parameter in the initial phase calculation formula with the radio frame number to generate the same initial phase.

a receiving module, configured to receive the same LRS from multiple source base stations on the same layer;

a first obtaining module, configured to obtain, from the LRSs, source base station sending time corresponding to each LRS, where the source base station sending time is based on a source base station clock;

a second obtaining module, configured to obtain local receiving times corresponding to arrival of the LRSs, where the local receiving times are based on a local clock;

and the operation module is used for performing operation by utilizing the source base station sending time and the local receiving time corresponding to the LRSs to obtain an average timing deviation estimated value.

The above configuration device further includes:

a third obtaining module, configured to obtain, before the operation module performs an operation, path propagation delay times corresponding to the LRSs;

the operation module is specifically configured to:

a third configuration module, configured to configure an LRS mode for the base station, so that the LRS sent by the base station is orthogonal to LRSs sent by other base stations in the same layer;

a sending module, configured to send the cell-scrambled LRS according to the LRS mode.

In the configuration apparatus, the LRS transmitted by the base station and LRS transmitted by other base stations in the same layer are respectively located in GP of different special subframes in the TDD system.

The above configuration device, wherein the third configuration module comprises:

a first sending unit, configured to send a signaling requesting feedback of an LRS mode used to a neighboring base station in the same layer;

a receiving unit, configured to receive response information fed back by the neighboring base station according to the signaling;

and the obtaining unit is used for obtaining an LRS mode which is different from LRS modes of all adjacent base stations in the local LRS mode database according to the response information.

a first determining unit, configured to determine a candidate subframe of an LRS to be transmitted;

a second sending unit, configured to listen to LRSs sent by other neighboring cells on the candidate subframe;

a second determining unit, configured to determine an unoccupied LRS configuration resource if the listening result indicates that the LRS configuration resource unoccupied by the LRS of the other neighboring cell exists in the candidate subframe;

a third determining unit, configured to determine an LRS mode according to the determined LRS configuration resource.

The above configuration device further includes:

and a circulating module, configured to continue to determine a candidate subframe of an LRS to be transmitted if the listening result indicates that all available LRS configuration resources of the candidate subframe are occupied by LRSs of other neighboring cells.

In the foregoing configuration device, in the same cluster, transmission periods of all LRSs are the same; if the micro station has the switch conversion function, the LRS is also sent even if the micro station is in a dormant state; the LRS has a characteristic point different from other signals and can be identified by other neighboring cells.

The technical scheme of the invention has the following beneficial effects:

in the above scheme, the method for configuring signal parameters in air interface synchronization configures the same LRS as a reference signal for the same-layer source base station, so that LRS signals sent by the same-layer source base station are additively enhanced to obtain signal diversity gain, or configures different LRS modes for the same-layer source base station, so that LRS signals sent by the same-layer source base station are orthogonal, thereby solving the problem of mutual interference caused by RE resource conflict of synchronization reference signals (LRS, listening RSs) sent by multiple source cells on the same layer in a small cell ultra-dense deployment scenario in the prior art, and improving the air interface synchronization performance of the network.

Drawings

Fig. 1 is a first schematic step diagram of a method for configuring signal parameters in air interface synchronization according to an embodiment of the present invention;

fig. 2 is a schematic diagram illustrating a second step of a method for configuring signal parameters in air interface synchronization according to an embodiment of the present invention;

fig. 3 is a third schematic step diagram of a method for configuring signal parameters in air interface synchronization according to an embodiment of the present invention;

fig. 4 is a first schematic structural diagram of a configuration apparatus for signal parameters in air interface synchronization according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a configuration apparatus for signal parameters in air interface synchronization according to an embodiment of the present invention;

fig. 6 is a third schematic structural diagram of a configuration apparatus for signal parameters in air interface synchronization according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating multi-hop synchronization according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of Method A according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a first Method B according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a second embodiment of a Method B;

fig. 11 is a schematic diagram illustrating an air interface synchronization principle applied in the embodiment of the present invention;

FIG. 12 is a schematic diagram of a Method C according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The invention provides a method for configuring signal parameters in air interface synchronization, aiming at the problem of mutual interference caused by RE resource conflict of synchronization reference signals (LRS, listening RS) sent by a plurality of source cells at the same layer under a small cell ultra-dense deployment scene in the prior art, as shown in FIG. 1, the method comprises the following steps:

step 11: configuring a reference signal serving as an LRS for a same-layer source base station, wherein the LRS of the same-layer source base station is the same;

step 12: configuring the same subframe offset for the LRS sent by the source base stations at the same layer, and configuring different subframe offsets for the LRS sent by the source base stations at different layers;

step 13: and controlling each source base station to send the LRS at the corresponding subframe position based on the subframe offset of the LRS configured by the source base station.

In the method for configuring signal parameters in air interface synchronization provided in the embodiment of the present invention, the same LRS is configured for the same-layer source base station as a reference signal, so that LRS signals sent by the same-layer source base station are additively enhanced to each other to obtain a signal diversity gain, thereby solving a problem of mutual interference caused by RE resource collision between synchronization reference signals (LRS, listening RSs) sent by multiple source cells on the same layer in a small cell super-dense deployment scenario in the prior art, and improving the network air interface synchronization performance.

Specifically, a preferred method for configuring the reference signal as the LRS for the peer source base station is to configure any one of CRS (Cell-specific reference signal), PRS (positioning reference signal) and CSI-RS (CSI reference signal, CSI is an abbreviation of Channel-State Information) as the reference signal of the LRS for the peer source base station, and configure the same initial phase for the any one of the reference signals.

It is not excluded to design a new reference signal, and when the new reference signal is configured as a reference signal of the LRS of the same-layer source base station, the sequence generation manner and the initial phase are completely the same.

Wherein configuring the same initial phase for the arbitrary reference signal comprises: the base station related parameters in the initial phase calculation formula are replaced with the radio frame number to generate the same initial phase.

Preferably, for CRS and PRS, the Cell-ID parameter is replaced by the radio frame numberFor CSI-RS, replacing parameters of higher layer configuration with radio frame number

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a method for configuring a signal parameter in air interface synchronization, where as shown in fig. 2, the method includes:

step 21: receiving the same LRS from a plurality of source base stations in the same layer;

step 22: acquiring the sending time of a source base station corresponding to each LRS from the LRSs, wherein the sending time of the source base station takes a source base station clock as a reference;

step 23: obtaining local receiving time corresponding to a plurality of LRSs when the LRSs arrive, wherein the local receiving time takes a local clock as a reference;

step 24: and calculating by using the sending time and the local receiving time of the source base station corresponding to the LRSs to obtain an average timing deviation estimated value. Wherein the estimated value comprises a measurement error value.

The method for configuring signal parameters in air interface synchronization provided by the embodiment of the invention further solves the problem of mutual interference of synchronization reference signals (LRS, listening RS) sent by a plurality of source cells at the same layer in a small cell ultra-dense deployment scene in the prior art due to RE resource conflict by processing LRS sent by a plurality of source cells at the same layer to obtain an average timing deviation estimated value, so as to improve the air interface synchronization performance of a network.

Before obtaining an average timing deviation estimated value by performing an operation using the source base station transmission time and local reception time corresponding to each of the plurality of LRSs, the method further includes: obtaining path propagation delay time corresponding to each of the LRSs; the calculating to obtain the average timing deviation value by using the source base station sending time and the local receiving time corresponding to the LRSs specifically includes: and calculating by using the sending time, the local receiving time and the path propagation delay time of the source base station corresponding to the LRSs to obtain an average timing deviation value.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a method for configuring a signal parameter in air interface synchronization, where as shown in fig. 3, the method includes:

step 31: configuring an LRS mode for a base station to ensure that the LRS sent by the base station is orthogonal to LRSs sent by other base stations in the same layer;

step 32: transmitting the cell-scrambled LRS according to the LRS mode.

According to the method for configuring signal parameters in air interface synchronization provided by the embodiment of the invention, different LRS modes are configured for the same-layer source base station, so that LRSs transmitted mutually are orthogonal, and the problem of mutual interference of synchronization reference signals (LRSs, listening RSs) transmitted by a plurality of source cells at the same layer in a small cell ultra-dense deployment scene in the prior art due to RE resource conflict is solved, so that the air interface synchronization performance of a network is improved.

The LRS sent by the base station and LRSs sent by other base stations in the same layer are respectively located in GP of different special subframes in the TDD system.

The invention preferentially adopts a distributed LRS mode scheduling mechanism, and specifically has two implementation forms, namely: the configuring an LRS mode for the base station includes: sending a signaling for requesting feedback of the used LRS mode to an adjacent base station in the same layer; receiving response information fed back by the adjacent base station according to the signaling; and acquiring an LRS mode which is different from LRS modes of all adjacent base stations in a local LRS mode database according to the response information.

And the second method comprises the following steps: the configuring method provided by the embodiment of the present invention, wherein the configuring an LRS mode for the base station includes: determining a candidate subframe of an LRS to be transmitted; monitoring LRSs sent by other adjacent cells on the candidate subframes; if the interception result is that the candidate subframe has LRS configuration resources which are not occupied by LRSs of other adjacent cells, determining an unoccupied LRS configuration resource; and determining an LRS mode according to the determined LRS configuration resource.

Further, if the interception result is that all available LRS configuration resources of the candidate subframe are occupied by LRSs of other neighboring cells, the candidate subframe of an LRS to be transmitted is determined continuously.

Wherein, in the same cluster, the transmission periods of all LRSs are the same; if the micro station has the switch conversion function, the LRS is also sent even if the micro station is in a dormant state; the LRS has a characteristic point different from other signals and can be identified by other neighboring cells.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a device for configuring a signal parameter in air interface synchronization, where as shown in fig. 4, the device includes:

The device for configuring signal parameters in air interface synchronization provided in the embodiment of the present invention configures the same LRS for the same-layer source base station as the reference signal, so that LRS signals sent by the same-layer source base station are additively enhanced to obtain signal diversity gain, thereby solving the problem of mutual interference caused by RE resource collision between synchronization reference signals (LRS, listening RSs) sent by multiple source cells on the same layer in a small cell super-dense deployment scenario in the prior art, and improving the network air interface synchronization performance.

Specifically, the first configuration module includes: a first configuration unit, configured to configure any one of a CRS (Cell-specific reference signal), a PRS (Positioning reference signal), and a CSI-RS (CSI reference signal, where CSI is an abbreviation of Channel-state information, and RS is an abbreviation of reference signal) as a reference signal of an LRS of a same-layer source base station; and the second configuration unit is used for configuring the same initial phase for the arbitrary reference signal.

Wherein the second configuration unit includes: a replacing component for replacing the base station related parameter in the initial phase calculation formula with the radio frame number to generate the same initial phase.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a device for configuring a signal parameter in air interface synchronization, as shown in fig. 5, including:

and the operation module is used for performing operation by utilizing the source base station sending time and the local receiving time corresponding to the LRSs to obtain an average timing deviation estimated value. Wherein the estimated value comprises a measurement error value.

The configuration device for signal parameters in air interface synchronization provided by the embodiment of the invention obtains an average timing deviation estimated value by processing the LRS sent by a plurality of source base stations in the same layer, and further solves the problem of mutual interference of synchronization reference signals (LRS, listening RS) sent by a plurality of source cells in the same layer in a small cell ultra-dense deployment scene in the prior art due to RE resource conflict, so as to improve the air interface synchronization performance of the network.

Wherein, still include: a third obtaining module, configured to obtain path propagation delay time corresponding to each of the LRSs before the operation module performs the operation;

the operation module is specifically configured to: and calculating by using the sending time, the local receiving time and the path propagation delay time of the source base station corresponding to the LRSs to obtain an average timing deviation value.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a device for configuring a signal parameter in air interface synchronization, as shown in fig. 6, including:

The configuration device for signal parameters in air interface synchronization provided by the embodiment of the present invention configures different LRS modes for a same-layer source base station, so that LRSs sent by each other are orthogonal, thereby solving the problem of mutual interference of synchronization reference signals (LRSs, listening RSs) sent by multiple source cells on the same layer in a small cell super-dense deployment scenario in the prior art due to RE resource collision, and improving the network air interface synchronization performance.

The invention preferentially adopts a distributed LRS mode scheduling mechanism, and specifically has two implementation forms, namely: the third configuration module comprises: a first sending unit, configured to send a signaling requesting feedback of an LRS mode used to a neighboring base station in the same layer; a receiving unit, configured to receive response information fed back by the neighboring base station according to the signaling; and the obtaining unit is used for obtaining an LRS mode which is different from LRS modes of all adjacent base stations in the local LRS mode database according to the response information.

Second, the third configuration module in the configuration apparatus provided in the embodiment of the present invention includes: a first determining unit, configured to determine a candidate subframe of an LRS to be transmitted; a second sending unit, configured to listen to LRSs sent by other neighboring cells on the candidate subframe; a second determining unit, configured to determine an unoccupied LRS configuration resource if the listening result indicates that the LRS configuration resource unoccupied by the LRS of the other neighboring cell exists in the candidate subframe; a third determining unit, configured to determine an LRS mode according to the determined LRS configuration resource.

Further, the method also comprises the following steps: and a circulating module, configured to continue to determine a candidate subframe of an LRS to be transmitted if the listening result indicates that all available LRS configuration resources of the candidate subframe are occupied by LRSs of other neighboring cells.

The following describes a configuration method of the signal parameter in the air interface synchronization according to an embodiment of the present invention.

Method A, multiple source cells in the same layer transmit completely same LRS signals in the same LRS transmission subframe, that is, the LRS signals of the cells in the same layer have the same pseudo code sequence and occupy the same RE resource.

The basic principle is as follows:

multiple source cells in the same layer transmit completely same LRS signals in the same LRS transmission subframe, that is, the LRS signals of the cells in the same layer have the same pseudo code sequence and occupy the same RE resource.

the target cell performs network interception in the LRS sending subframe, and the received signal is a superposition of LRS signals (called as LRS components) sent by multiple sourcecells on a time domain.

the target cell estimates the arrival Times (TOAs) of all LRS components through a time domain correlation operation (or other similar operations), but because the pseudo code sequences of all LRS components are the same, the target cell cannot correctly identify from which source cell these LRS components with different arrival times are emitted.

Focusing on the node eNB 2-2 with stratum level 2 in fig. 7, it receives LRS signals of three source cells (eNB 1-1, eNB1-2, and eNB 1-3, respectively) of the previous hop (stratum level 1) at the same time in the LRS transmission subframe with stratum level 1. These LRS signals have the same pseudo code sequence, and time-frequency resources.

For simplicity of description, source cells eNB1-1, eNB1-2 and eNB 1-3 are respectively denoted as S1, S2 and S3, and target cells eNB 2-2 are respectively denoted as target cells T. As shown in fig. 8, source cells S1, S2, and S3 all transmit an LRS signal at local time 0(LRS transmission subframe). Due to the timing synchronization errors of S1, S2 and S3, the actual sending time of the LRS signal is t respectively by using GNSS timing (GNSS timing) as reference timing (reference timing)_TX1＝δ_S1、t_TX2＝δ_S2And t_TX3＝δ_S3. Meanwhile, the initial timing synchronization error of the target cell T is assumed to be T_target＝δ_T. Consider the path propagation delay τ from S1, S2, and S3 to target cell T_S1、τ_S2And τ_S3Then, the arrival times of the LRS signals sent at S1, S2 and S3 in GNSS to reach the target cell T are T_RX1＝δ_S1+τ_S1、t_RX2＝δ_S2+τ_S2And t_RX3＝δ_S3+τ_S3。

the signal received by the target cell T is actually a combination of the LRS signals sent by S1, S2 and S3 in the time domain, the arrival time of each LRS component expressed in GNSS time is shown as an image on the corresponding axis of a receiver sig @ T in FIG. 8, and is T_RX1＝δ_S1+τ_S1、t_RX2＝δ_S2+τ_S2And t_RX3＝δ_S3+τ_S3。

As shown in fig. 8, the time of arrival (TOA) of each received signal component represented by the local time of the target cell is TOA_RX1＝t_RX1-t_target＝(δ_S1-δ_T)+τ_S1、TOA_RX2＝t_RX2-t_target＝(δ_S2-δ_T)+τ_S2And TOA_RX3＝t_RX3-t_target＝(δ_S3-δ_T)+τ_S3。

the target cell T first generates a local reproduction signal replica of the LRS, and then performs time domain correlation (or other similar operations) on the replica and the received signal to obtain a composite correlation function combination ACF, where the curve is shown as the image on the axis corresponding to the combination ACF @ T in fig. 8. The horizontal axis position corresponding to the peak of the ACF function represents the signal propagation time expressed by the local time of the target cell. By the position of the peak of the ACF function, the estimated amount of the signal arrival time TOA expressed by the local time of the target cell can be estimatedNamely, it isWherein epsilon_S1、ε_S2And ε_S3Representing the TOA estimation error (i.e., measurement error). Can assume epsilon_S1、ε_S2And ε_S3Independently distributed and mean 0.I.e. the raw moveout measurement obtained for the target cell.

Finally, the target cell T generates an estimated value of the timing deviation according to the TOA information of each LRS component and some other auxiliary informationSo that it is approximately equal to the average timing offset of the last hop source base station. When obtaining a timing deviation estimatorThen, the target cell is based onAnd calibrating the local clock to make the average timing deviation of the local clock approximately equal to the average timing deviation of the last-hop source base station, namely realizing the clock synchronization function of the adjacent 2-hop base station.

Propagation delay tau when path of all source cells_SiCan be completely ignored, haveAndthe timing offset of the target cell can now be estimated by simple arithmetic averaging, i.e.

Timing relation:

timing offset estimator:

where definition is expressed, E { □ } represents averaging, and the mean E { ε of the measurement noise_Si0. Thus of the above formulaThe rational is that the path propagation delay T_SiWhen it can be ignored, the timing offset estimate of the target cell can be determinedDefined as the negative of the mean value of the TOAs, and the timing offset estimate calculated from this definition is approximately equal totrue timing deviation δ of target cell_TMean value of timing deviations E δ from all source base stations of the last hop_SiThe difference. To obtainThen, the target cell adjusts the local clock such that the calibrated local clock timing offset is approximately equal toMean value of timing offsets E [ delta ] of all source base stations of previous hop_SiI.e. that

However, when the path propagation delay τ of the source cell is large_SiWhen large and not negligible, the timing offset estimator of the target cell cannot be estimated by a simple TOA algorithm, which is an averaging algorithmHowever, in Method A, the LRS sequences of all LRS components are the same, soIt is difficult for the target cell T to associate the LRS component with a specific source cell, i.e. to use a priori information (e.g. path propagation delay τ)_Si) The TOA estimate of the LRS component is calibrated (meaning that the path propagation delay τ is calibrated)_SiEffect on TOA measurement). Propagation delay tau when certain source cell paths propagate_SiWhen the system bias is larger, a larger system bias may be caused to the target cell T timing bias estimation algorithm. Different timing deviation estimation methods will be given according to 3 different application scenarios.

Source cell side processing:

source cells of the same stratum level use the same LRS subframe offset (subframe offset), while different stratum levels use different LRS subframe offsets.

The source cells with the same stratum level transmit completely same LRS signals in the same LRS transmission subframe, that is, the LRS signals of the cells in the same layer have the same pseudo code sequence and occupy the same RE resource. Therefore, the LRS signal here is independent of the cell ID.

One embodiment is to scramble the LRS by radio frame number (SFN) instead of cell ID.

For example, when the LRS signal is CSI-RS (CSI reference signals, which is an abbreviation of Channel-State Information, and RS is an abbreviation of reference signal), the initial phase (initial phase calculation formula) of the pseudo code sequence thereof is

Wherein,

wherein n is_sIs the Slot number within the radio frame (Slot number with a radio frame), l isAn OFDM symbol number within one slot with the slot,numbering CSI for the cell; n is a radical of_CPFor cyclic prefix type parameters, when a normal cyclic prefix (normal CP) is used, N_CPOtherwise, when an extended cyclic prefix (extended CP) is used, N_CP＝0；c_initIs the initial phase of the pseudorandom sequence.

Can be used forConfigured to SFN number through higher layer signaling. This embodiment does not require modification of existing standards.

In embodiment 2, when the LRS signal is CRS (Cell-specific reference signal) or PRS (Positioning reference signal), the initial phase (initial phase calculation formula) of the pseudo code sequence is CRS

The main parameters are the same as above, the main difference isRepresenting a cell number (cell ID). This embodiment requires modification of the initial phase cinit of the LRS generation sequenceParameter(s) ofModified to SFN number.

Similar configurations are possible if the LRS uses other reference signals.

Target cell side processing:

according to different deployment scenarios of small cells, the processing mode of the target cell side is different. There may be 3 types of main deployment scenarios:

in the first deployment scenario, all target cells can always find a sourcecell which is very close to the target cell, and the path propagation delay between the target cells and the sourcecell is negligible.

According to the assumption, the shortest path propagation delay tau from all source base stations of the (n-1) th hop to the (n) th hop target cell_S1Can be ignored, and the timing deviation estimator of the nth-hop target cell can be defined by two methods

The first method comprises the following steps: setting a received signal power threshold. Specifically, when the peak ACF power of an LRS component is below a certain threshold, the LRS component does not participate in the target cell T timing offset estimation. The received signal power threshold may be an absolute power value or a relative power value with the first LRS component received power as a reference. The mathematical expression is:

timing offset estimator for target cell

Wherein mean represents the arithmetic mean, and the letters below mean represent that the relative powers of the M LRS components participating in the averaging operation are all greater than or equal to a certain threshold. Since the greater the path propagation delay, the greater the power attenuation of the received signal, resulting in a reduction in the associated power. Therefore, by setting the threshold, the path propagation delay tau of all the source base stations participating in the average operation can be ensured_SiAre small and can be ignored, i.e., τ_Si≈0。

The formula of TOA is substituted into the aboveIn the formula (II) to analyzeThe intrinsic principles of the formula are defined. It is known thatThen

I.e., the timing offset estimator is approximately equal to the true timing offset δ of the target cell_TAll source bases of last hopMean value of timing offsets E [ delta ] of stations_SiThe difference. After obtaining, the target cell adjusts the local clock to make the local clock after calibrationIs approximately equal to the mean of the timing offsets E δ of all the source base stations of the last hop_SiI.e. that

And the second method comprises the following steps: the received signal power is weighted. Specifically, when estimating the T timing offset of the target cell, the received power P of the LRS component is utilized_iEstimate TOA for TOA_RXiAnd (4) weighting. Received power P_iThe larger the size of the tube is,the greater the weight of (c). A possible mathematical expression is

timing offset of target cell

Where g (□) is some increasing function.

Since the greater the path propagation delay, the greater the power attenuation of the received signal, resulting in a reduction in the associated power. Therefore, by setting the threshold, the path propagation delay tau can be ensured_SiThe weighted contribution of the large source base station to the timing offset estimate of the target cell is relatively small, while the path propagation delay τ of the source base station with the relatively large weighted contribution is relatively large_SiAre small and the resulting total path propagation delay effect can be neglected.

Then

Based on the assumption, the path propagation delay τ_SiThe weighted contribution g (P) of the large source base station to the timing offset estimator of the target cell_i) Path propagation delay tau of source base station being relatively small and weighted contributing relatively large_SiAre all relatively small, therefore

Can finally obtainI.e. timing deviation estimatorApproximately equal to the true timing deviation δ of the target cell_TMean value of timing deviations E δ from all source base stations of the last hop_SiThe difference. To obtainThen, the target cell adjusts the local clockBiasing calibrated local clock timingApproximately equal to the mean value E [ delta ] of the timing offsets of all source base stations of the last hop_SiI.e. that

A second type deployment scenario is that only the path propagation delay from a 0 th hop base station (such as a macro station) to a 1 st hop base station (small cell) is large and can not be ignored; and the path propagation delay of the first LRS component from the nth hop base station (n ≧ 1) to the (n + 1) th hop base station (small cell) can be ignored.

In the application scenario, the timing offset of the 1 st hop base station and the timing offset of the nth hop (n ≧ 2) can be respectively estimated by different methods.

The method for estimating the timing offset of the 1 st hop base station is first described below. In this application scenario, only 10 th hop base station (e.g., macro station) in one cluster may be required by configuration, and the path propagation delay τ between the 1 st hop target cell and the 0 th hop base station may be measured in advance by a class-based method_S1The TOA relationship is as follows:thus, a timing offset estimator for a target cell may be definedDefined as propagation delay τ by path_S1Calibrated TOA, i.e.:timing deviation delta of 0 th hop base station (such as macro station) is not set_S1Approximately 0, timing measurement error ε_S1Has an average value of 0, thenNamely target cell timing offset estimatorApproximately equal to the true timing offset.

And the timing deviation estimation method of the nth hop (n is more than or equal to 2) base station is the same as the first type deployment scene.

In a third deployment scenario, except that the path propagation delay from a 0-th hop base station (such as a macro station) to a 1-th hop base station (small cell) cannot be ignored, the path propagation delay from an nth hop base station (n ≧ 1) to a first LRS component of an n + 1-th hop base station (small cell) cannot be ignored either.

In this application scenario, the synchronization method from hop 0 to hop 1 may refer to the second type deployment scenario.

The following mainly describes a synchronization method from the nth hop base station (n ≧ 1) to the (n + 1) th hop base station (small cell). When the path propagation delay of the first LRS component is not negligible, it needs to be calibrated (i.e., the path propagation delay of the first LRS component is added, which is equivalent to excluding the path propagation delay influence of the first LRS component from the target cell timing offset estimate).

The processing steps are as follows:

step1, the target cell measures the path propagation delay with all the adjacent base stations in advance through the implementation method, and a mapping table of the path propagation delay and the base station pair is made, wherein the format of the mapping table can be < path propagation delay, fromcell ID, to cell ID >. This measurement can be done when the target cell is restarted. All base stations in the whole cluster can be restarted in turn when the UE service is inactive in every day/late night every week, and the path propagation delay between every two is measured;

step 2: the target cell selects a synchronization source cell. The specific selection method may refer to the existing 3GPP standard. Setting the stratum level of the source cell to be n-1, and setting the stratum level of the target cell to be n;

step 3: the target cell obtains the offset of the LRS subframe sent by the source cell. the target cell further obtains a set of cell IDs of neighboring source cells of stratum level n-1. the target cell may obtain the cell ID information of the neighboring sourcecell through blind detection of PSS/SSS signals in Step2 or backhaul signaling (e.g., through X2/S1 interface). the target cell searches a mapping table of the path propagation delay and the base station pair determined by Step1 according to the obtained cell ID set of the adjacent source cell<Path propagation delay, from cell ID, to cell ID>Obtaining shortest path tau from target cell to adjacent source cell of stratum level n-1_min；

Step 4: in the same first category, in order to suppress the influence of the LRS component with a large path propagation delay on the estimation of the target cell T timing offset, two technical approaches may be adopted:

setting a received signal power threshold and then defining

timing offset of target cell

Received signal power weighting, i.e. defining

timing offset of target cell

Where g (□) is some increasing function. Other function definitions may refer to the first type of deployment scenario. Wherein, tau_minNot necessarily equal to the path propagation delay of the first LRS component, but generally better path propagation delay calibration and air interface synchronization performance can be obtained.

And a Method B, sending the LRS signals scrambled by the cells in the same or different downlink subframes by a plurality of source cells in the same layer according to the requirements, and ensuring that the LRS signals from different source cells in the same layer are orthogonal to each other through a proper scheduling mechanism. During normal operation (without loss of synchronization), the target cell listens to the LRS signal of only one synchronization source at a time to maintain air interface synchronization.

The core idea of the Method B in the embodiment of the invention is that a stripe level is bound with an LRS subframe offset range; this allows to completely suppress the interference between LRS signals of the same layer.

As shown in fig. 9 and 10, multiple source cells in the same layer transmit cell-scrambled LRSs in the same or different downlink subframes. The cell-scrambled LRS signal may be legacy RS (reference signal), such as CRS, PRS, CSI-RS, etc., or may be a newly designed reference signal.

To ensure that LRS signals from multiple source cells on the same layer are orthogonal to each other, RE (resource element) resources corresponding to the LRS signals may be staggered in a subframe dimension and/or a frequency dimension within a subframe and/or an OFDM (orthogonal frequency division multiplexing) symbol dimension within a subframe. The offsets include both time domain offsets (subframe level offsets and symbol offsets-OFDM symbol offsets) and frequency domain offsets (i.e., frequency offsets/subcarrier offsets).

Specifically, different LRS signals have different frequency dimension multiplexing degrees (i.e., the LRS signals are staggered by subcarrier shifting in the frequency domain), for example, the frequency dimension multiplexing degree of a 2-port CRS is 3, and the frequency dimension multiplexing degree of a PRS is 6. When the number of source cells in the same layer is too large to orthogonally transmit the LRS signal in the same subframe, a new multiplexing dimension, i.e., a subframe offset dimension, may be introduced to ensure the orthogonality of the LRS signal, and a specific offset method is shown in fig. 9 and fig. 10.

The muting (listening) mechanism between different stratum levels can ensure better synchronous interception performance. Fig. 9 and 10 show two different mutting mechanisms. Fig. 9(Opt1) shows that all mutes are across layers, that is, no matter which subframe on the stratumlevel transmits the LRS signal, all base stations of other stratumlevels are muted (do not transmit data) at the same subframe to avoid interfering with the LRS signal listening performance. Fig. 10(Opt2) shows neighbor-layer listening, i.e., when the nth layer base station transmits an LRS signal, the n +2 th layer is muted to avoid interfering with the LRS signal listening performance of the n +1 th layer.

Multiple base stations in the same layer coordinate their LRS transmission resources (including transmission subframes, subcarrier offsets and OFDM symbols within the transmission subframes) through interactive backhaul signaling to ensure that their RE resources corresponding to their LRS signals are staggered.

Several possible scheduling mechanisms are illustrated below to ensure that LRS signals from different source cells in the same layer are transmitted in a staggered manner on different time-frequency resources.

And Option 1: a centralized RS pattern scheduling mechanism is adopted: there is a central controller that centrally manages the listening RS patterns of all eNB target base stations and guarantees their orthogonality. Specifically, the central controller maintains an LRS pattern database.

1. When a base station wants to determine where to send an LRS signal, it first sends a request signaling to the central controller requesting to feed back an LRS pattern that does not cause collision;

2. the central controller selects an LRS pattern which does not conflict with the LRS patterns of all the existing base stations according to the maintained LRS pattern database, and feeds back the information to the requesting base station through signaling;

3. the central controller adds the fed-back LRS pattern into an LRS pattern database to update and maintain the database;

4. requesting the base station to send an LRS signal according to an LRS pattern fed back by the central controller;

5. the request and feedback signaling can be transmitted through backhaul (such as an S1 interface, an X2 interface);

6. the LRS pattern at least includes information such as LRS subframe offset and LRS signal repetition period.

And Option 2: there are two implementation mechanisms for the distributed RS pattern scheduling mechanism.

Alt 1 is based on backhaul signaling. Each eNB consults LRS configuration information of adjacent or all base stations through backhaul signaling to determine the LRS configuration information of the eNB so as to ensure the LRS signal orthogonality with LRS signals of other eNBs, and the specific steps include:

1. when a base station wants to determine where to send an LRS signal, the base station firstly sends a request signaling to an adjacent base station to request the other side to feed back the LRS pattern used by the other side;

2. the adjacent base station sends the request and feeds back the LRS pattern used by the adjacent base station to the requesting base station;

3. the requesting base station maintains a local LRSpattern database according to all the collected LRS patterns of the adjacent base stations, and then selects an LRS pattern which does not conflict with the LRS patterns of all the adjacent base stations according to the database;

4. and requesting the base station to send the LRS signal according to the currently selected LRS pattern.

And Alt 2, each eNB firstly monitors (blind detects) LRS signals of other eNBs through an air interface, and then configures the LRS configuration information of each eNB based on the monitoring result so as to ensure the LRS signals of the other eNBs to be orthogonal. The method comprises the following specific steps:

1. when a base station (called as a current base station) wants to determine where to transmit an LRS signal, the base station firstly determines a candidate subframe of the LRS signal to be transmitted, and then listens for LRS signals transmitted by other adjacent cells on the candidate subframe (blind detection);

2. in order to avoid the influence of the listening process on the traffic of the current base station UE, the current base station may configure a measurement gap (measurement gap). In particular, the measurement interval may be configured as an MBSFM (multicast/multicast single frequency network) subframe;

3. if the current base station finds that all available LRS configuration resources of the candidate subframe are occupied by LRS signals of other cells through blind detection, the current base station reselects a candidate subframe of an LRS signal to be transmitted, and then executes the step1 again;

4. otherwise, if the candidate subframe is not occupied by the LRS signals of other cells through blind detection, the current base station occupies the subframe and selects an unoccupied LRS configuration resource to send the LRS signals.

In addition, in order to avoid the hearing loss, the following constraint conditions need to be additionally met:

constraint 1: in the same cluster, the transmission periods of all the listening RSs are the same;

constraint 2: if a small cell with an on/off switching function exists, requiring that an off cell also sends a boosting RS;

constraint 3: the LRS needs to be distinguishable from non-LRS signals, e.g., the LRS signal is a newly designed reference signal and can be blindly detected by other neighboring cells.

And a Method C, sending the LRS signals scrambled by the cells in different downlink subframes by a plurality of source cells in the same layer according to the requirements, sending the LRS signals only in a special subframe of the TDD system, and ensuring that the LRS signals from different source cells in the same layer are orthogonal to each other by using the same scheduling mechanism as the Method B. The specific configuration of its LRS signal is seen in the scheme in patent application 201410035839.9, as follows:

an air interface synchronization scheme for transmitting an LRS signal by using a GP (guard interval) of a TDD (time division duplex) special subframe, as shown in fig. 11, a TDD source cell transmits an LRS signal in the GP of a special subframe. One possible embodiment is: the ratio of uplink and downlink time slots of the special subframe is 9: 3: 2, downlink DwPTS (downlink pilot time slot) occupies 9 OFDM symbols, GP occupies 3 OFDM symbols, and uplink UpPTS (uplink pilot time slot) occupies 2 OFDM symbols. The Source cell transmits the LRS signal using the first OFDM symbol of the GP. The LRS signal may be a legacy RS (e.g., CRS, PRS, CSI-RS, etc.), and the term "clipping" refers to transmitting a legacy RS (reference signal) signal only on the LRS transmitting OFDM symbol and not transmitting data on any other OFDM symbol.

The scheme shown in fig. 11 skillfully utilizes the advantage that data is not transmitted on GP of TDD special subframe, and can automatically implement cross-layer total muting function. Therefore, the scheme has better synchronous interception performance.

On the other hand, the scheme is completely transparent to the UE and has ideal backward compatibility.

However, the scheme shown in fig. 11 has a certain system overhead, i.e. all base stations are required to reserve (vacate) several (≧ 1) OFDM symbols in GP for transmitting/listening to LRS signal, which may cause a certain resource overhead and waste. However, if the number of OFDM symbols occupied by the LRS signal is small (e.g., ═ 1), the traffic rate is hardly affected, because the traffic rate is determined by the TBS (transport block size), and the use or non-use of one OFDM symbol has little influence on the TBS, for example, the uplink and downlink slot allocation 9: 3: 2 (adopted in the solution of patent application 201410035839.9) and 10: 2: 2 (compare scheme, LRS of 1 OFDM symbol is released for traffic communication) generally has TBS of the system, so the traffic rates of both are the same. Of course, although both TBSs are the same, the transmission bit sizes of both are different, which affects the coding/decoding performance. The overhead of the solution in patent application 201410035839.9 can therefore be expressed as: the coding/decoding performance (reflected as robustness) is slightly degraded on the premise that the TBS (reflected as traffic rate) remains substantially unchanged.

The Method C enhances the scheme shown in the figure 11 from the perspective of mapping stratum level and subframe offset aiming at an ultra-dense deployment scene of the small cell.

As shown in fig. 12, a synchronization level is associated with a certain LRS subframe offset set through a suitable scheduling mechanism, so as to ensure that multiple source cells in the same layer transmit cell-scrambled LRS signals in different downlink subframes.

On the basis of the Method B, the combination scheme can automatically realize a cross-layer mutting mechanism, so that additional system overhead is not required to be introduced, and a further excellent effect is achieved.

In summary, when a future small cell more dense deployment scenario (e.g., 5G UDN: ultra dense network) is oriented, there may be more than 60 small cells in a cluster, and there may be more than 7 small cells per hop (layer), if the existing RIBS technology is adopted, that is, the base stations in the same layer respectively send LRS signals scrambled by their respective cell IDs in the same subframe, then since the number of source cells in the same layer exceeds the reuse degree of the LRS signals, these LRS signals are difficult to be completely staggered on RE resources even through cell planning, and thus interfere with each other and reduce the network air interface synchronization performance.

The embodiment of the invention provides 3 types of RIBS parameter configuration schemes and embodiments aiming at the problem that LRS signals sent by a plurality of source cells on the same layer interfere with each other in air interface synchronous application under a small cell ultra-dense deployment scene:

method A, multiple source cells in the same layer transmit completely same LRS signals in the same LRS transmission subframe, that is, the LRS signals of the cells in the same layer have the same sequence and occupy the same RE resource.

And a Method B, sending the LRS signals scrambled by the cells in the same or different downlink subframes by a plurality of source cells in the same layer according to the requirements, and ensuring that the LRS signals from different source cells in the same layer are orthogonal to each other through a proper scheduling mechanism.

Method C, combining Method B with the scheme in patent application 201410035839.9, namely RIBS scheme for transmitting LRS signals in GP of TDD special sub-frame, defines a new corresponding relation between synchronization level and LRS transmission sub-frame offset (LRS sub-frame offset for short), that is, through a proper scheduling mechanism, one synchronization level is corresponding to a certain LRS sub-frame offset set (LRS subframe offset range, and the number of offsets in the set is more than or equal to 1) to ensure that multiple source cells at the same layer transmit the LRS signals scrambled by cells in different downlink sub-frames.

The RIBS parameter configuration technology provided by the embodiment of the invention can solve the problem of mutual interference caused by RE resource conflict of synchronous reference signals sent by a plurality of source cells at the same layer in a small cell ultra-dense deployment scene, thereby effectively ensuring the inter-station air interface synchronization performance in the small cell ultra-dense deployment scene.

While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. A method for configuring signal parameters in air interface synchronization is characterized by comprising the following steps:

configuring a reference signal serving as a synchronous reference signal (LRS) for a same-layer source base station, wherein the LRS of the same-layer source base station is the same;

2. The method of claim 1, wherein configuring the reference signal as the LRS for the peer-to-peer source base station comprises:

any one of a cell common reference signal CRS, a positioning reference signal PRS and a channel state information reference signal CSI-RS is configured as a reference signal of an LRS of a same-layer source base station, and the same initial phase is configured for the any one of the reference signals.

3. The method of claim 2, wherein said configuring the same initial phase for the arbitrary reference signal comprises:

4. A method for configuring signal parameters in air interface synchronization is characterized by comprising the following steps:

receiving the same synchronization reference signal LRS from a plurality of source base stations in the same layer;

calculating by using the sending time and the local receiving time of the source base station corresponding to the LRSs to obtain an average timing deviation estimated value;

before obtaining an average timing deviation estimated value by performing an operation using the source base station transmission time and local reception time corresponding to each of the plurality of LRSs, the method further includes:

obtaining path propagation delay time corresponding to each of the LRSs;

dividing the source base station into three types of deployment scenes according to the path propagation delay time; the deployment scenes comprise a first type deployment scene corresponding to the path propagation delay time of 0, a second type deployment scene corresponding to the path propagation delay time of 0 and a third type deployment scene corresponding to the path propagation delay time of 0;

and according to the three types of deployment scenes, calculating by using the sending time and the local receiving time of the source base station corresponding to the LRSs to obtain an average timing deviation value.

5. A method for configuring signal parameters in air interface synchronization is characterized by comprising the following steps:

configuring an LRS mode for the base station according to the LRS mode of the synchronous reference signal used by the adjacent base station, so that the LRS sent by the base station is orthogonal to LRSs sent by other base stations in the same layer;

transmitting the cell-scrambled LRS according to the LRS mode.

6. The method of claim 5, wherein the LRS transmitted by the BS and the LRS transmitted by other BSs in the same layer are respectively located in the guard period GP of different special subframes in the TDD system.

7. The method of claim 5, wherein the configuring an LRS mode for the base station itself comprises:

8. The method of claim 5, wherein the configuring an LRS mode for the base station itself comprises:

determining a candidate subframe of an LRS to be transmitted;

monitoring LRSs sent by other adjacent cells on the candidate subframes;

9. The configuration method of claim 8, further comprising:

10. The method of claim 8, wherein the transmission periods of all LRSs are the same within the same cluster; if the micro station has the switch conversion function, the LRS is also sent even if the micro station is in a dormant state; the LRS has a characteristic point different from other signals and can be identified by other neighboring cells.

11. An apparatus for configuring signal parameters in air interface synchronization, comprising:

a first configuration module, configured to configure a reference signal as a synchronization reference signal LRS for a same-layer source base station, where the LRSs of the same-layer source base station are the same;

12. The configuration apparatus of claim 11, wherein the first configuration module comprises:

a first configuration unit, configured to configure any one of a cell common reference signal CRS, a positioning reference signal PRS, and a channel state information reference signal CSI-RS as a reference signal of an LRS of a same-layer source base station;

13. The configuration apparatus according to claim 12, wherein the second configuration unit includes:

14. An apparatus for configuring signal parameters in air interface synchronization, comprising:

a receiving module, configured to receive the same synchronization reference signal LRS from multiple source base stations on the same layer;

the computing module is used for computing by utilizing the source base station sending time and the local receiving time corresponding to the LRSs to obtain an average timing deviation estimated value;

wherein the configuration device further comprises:

a third obtaining module, configured to obtain path propagation delay time corresponding to each of the LRSs before the operation module performs the operation;

the operation module is specifically configured to:

15. An apparatus for configuring signal parameters in air interface synchronization, comprising:

a third configuration module, configured to configure an LRS mode for the base station according to the LRS mode used by the neighboring base station, so that the LRS sent by the base station is orthogonal to LRSs sent by other base stations in the same layer;

16. The apparatus of claim 15, wherein the LRS transmitted by the base station and LRSs transmitted by other base stations in the same layer are respectively located in guard intervals GP of different special subframes in the TDD system.

17. The configuration apparatus of claim 15, wherein the third configuration module comprises:

18. The configuration apparatus of claim 15, wherein the third configuration module comprises:

19. The configuration device of claim 18, further comprising:

20. The apparatus of claim 18, wherein the transmission periods of all LRSs are the same within the same cluster; if the micro station has the switch conversion function, the LRS is also sent even if the micro station is in a dormant state; the LRS has a characteristic point different from other signals and can be identified by other neighboring cells.