WO2016070693A1

WO2016070693A1 - Method and device for transmitting preamble signal

Info

Publication number: WO2016070693A1
Application number: PCT/CN2015/090926
Authority: WO
Inventors: 王加庆; 潘学明; 徐伟杰; 沈祖康
Original assignee: 电信科学技术研究院
Priority date: 2014-11-04
Filing date: 2015-09-28
Publication date: 2016-05-12
Also published as: CN105635017A; CN105635017B

Abstract

Disclosed are a method and device for transmitting a preamble signal, so as to implement occupation of an LTE system in an unlicensed spectrum through a preamble signal and accordingly enable the LTE system to work in the unlicensed spectrum. The method for sending a preamble signal provided by the present application comprises: when random channel access is implemented in an unlicensed spectrum, a base station determines a preamble signal to be sent; and in the full bandwidth or partial bandwidth of an access channel in the unlicensed spectrum, the base station sends the preamble signal to a user equipment (UE).

Description

Method and device for transmitting preamble signal

The present application claims priority to Chinese Patent Application No. 201410613675.3, entitled "Transmission Method and Apparatus for a Preamble Signal", filed on November 4, 2014, the entire contents of which is incorporated herein by reference. In the application.

Technical field

The present application relates to the field of communications technologies, and in particular, to a method and a device for transmitting a preamble signal.

Background technique

As the volume of mobile data continues to grow, spectrum resources become more and more tense. Only the use of licensed spectrum resources for network deployment and service transmission may not meet the traffic demand. Therefore, the Long Term Evolution (LTE) system can be considered. The LTE system is an unlicensed LTE (Unlicensed LTE, U-LTE or LTE-U) system to improve user experience and extended coverage. However, there is currently no clear solution on how LTE systems work on unlicensed spectrum resources.

The unlicensed spectrum does not have a specific application system, and can be shared by various wireless communication systems such as Bluetooth, WiFi, etc., and the shared unlicensed spectrum resources are used by multiple systems by preempting resources. Therefore, the coexistence of LTE-U deployed by different operators and wireless communication systems such as LTE-U and WiFi is a key point and difficulty in research. The 3GPP requires that the wireless coexistence of LTE-U and wireless communication systems such as WiFi be guaranteed. The unlicensed frequency band is used as a secondary carrier to be assisted by the primary carrier of the licensed frequency band. Listening before Talk (LBT) is the basic means of LTE-U competitive access, which is approved by almost all companies. The essence of LBT technology is still that the 802.11 system adopts the carrier sense/collision avoidance (CSMA/CA) mechanism. The way in which the WiFi system preempts resources on the unlicensed spectrum includes: first, listening to the channel, when the channel idle time reaches the DCF interframe distance (DCF Inter-Frame Space, DIFS; DCF, distributed channel access, distributed channel access), it is judged that the current channel is an idle channel, and then each station waiting for access to the channel enters a random back-off phase for Avoid multiple sites colliding on the same resources. In addition, in order to ensure fairness, it is also stipulated that each site cannot occupy spectrum resources for a long time. When a certain time or data transmission limit is reached, resources need to be released for other WiFi or LTE systems to seize resources.

The LTE system supports both FDD and TDD duplex modes, and the two duplex modes use different frame structures. Common to both frame structures is that each radio frame consists of 10 1 ms subframes. The first type of frame structure used by the FDD system is shown in Figure 1, and the second type of frame structure used by the TDD system is shown in Figure 2.

From the perspective of the current protocol and its engineering implementation, even if it is carrier aggregation of FDD, the primary carrier and the secondary carrier are also synchronized in time. Since the time when the LTE-U monitors the channel and judges to be "free" is random, LTE-U letter The starting time of the number transmission may be any position of a certain subframe. On the other hand, even if the LTE access moment happens to be the starting point of a certain subframe, the base station may not be able to send the control channel and data in time due to factors such as data preparation or radio frequency. . It can be seen from the LTE frame structure that the signal transmission is in units of 1 ms subframes. If the LTE-U does not send a signal after robbing the channel, it will inevitably be snatched by other nodes in the case of fierce competition, which greatly reduces the number of frames. The competitive access capability of LTE-U is unlikely to be adopted.

At the same time, it is noted that, in the case of FDD, a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) sequence are located in the first subframe and the fifth subframe of each radio frame. The probability that the subframe of the contention access is not a PSS subframe is large. Therefore, according to the conventional method of LTE, the subframe cannot be decoded in real time, which inevitably affects the hybrid automatic retransmission (Hybrid-ARQ, HARQ) process. Alternatively, the frame is a PSS subframe but the access time cannot be synchronized after the PSS. Because the synchronization is not timely, the base station cannot receive the acknowledgement (ACK) message of some previous subframes, and can only retransmit, which is acceptable for LTE, but for LTE-U with limited transmission time, resource waste serious.

In the actual deployment scenario of a small cell, the number of user equipments (UEs) served by a single small cell transmission point (TP) is small, so the traffic load of a single small cell/TP in different time periods. If the small cell/TP has no service transmission, you can use the small cell on/off technology to enable or disable the small cell/TP according to the actual service situation. In order to enable the UE to discover the closed small cell/TP so that the UE can have the closed cell when there is a service transmission, the small cell/TP needs to periodically send the discovery signal. At present, 3GPP has reached a conclusion that it is found that the signal is periodically transmitted (the period is 40ms/80ms/160ms), and the discovery signal includes the PSS/SSS/Common Reference Signal (CRS), and the channel state information reference signal can also be configured. Channel State Information Reference Signal (CSI-RS) is used for the identification of small cell/TP. In order to allow the UE to measure the discovery signal using the measurement call gap (GAP), the signal is found. The length can be configured, the FDD is 1 to 5 subframes, and the TDD is 2 to 4 subframes.

If the unlicensed band also transmits the discovery signal periodically like the small cell, since the PSS/SSS/CRS sequence is configured in the discovery signal, a very possible implementation scheme is to realize the time and frequency synchronization by using the discovery signal. In case 1, it is found that the signal is well received. At this time, the UE can achieve synchronization well. In the second case, since the discovery signal is intermittently interrupted by WiFi interference, the coarse frequency offset and the coarse symbol timing are not much problematic, such as fractional multiple frequency offset. The timing synchronization between fine and fine symbols may be lost; in the third case, the deployment of 802.11ac can occupy 80M or 160M bandwidth of the unlicensed band, and the competition in the hot spot is fierce, and the discovery signal is sparse and the signal is easily collided with the WiFi signal, which may result in For a long time, it is found that the signal cannot be received normally and the coarse synchronization is lost. Except for the scenario where the signal is found to be invalid, the unlicensed band has a large number of selectable frequency points. For the UE, the discovery signal needs to be received at all frequency points, and the complexity and power consumption are higher than the small cell case. It is found that the signal has a large overhead for occupying multiple subframes, so it is also necessary to consider the discovery of signal failure or a possible discovery signal alternative from a technical point of view.

In summary, how the LTE system works on the unlicensed spectrum has not yet given a clear solution.

Summary of the invention

The embodiment of the present application provides a method and a device for transmitting a preamble signal, which are used to implement a vacancy in an unlicensed spectrum of an LTE system by using a preamble signal, thereby implementing an LTE system working on an unlicensed spectrum.

A method for transmitting a preamble signal provided by an embodiment of the present application includes:

The base station determines a preamble signal to be transmitted when randomly accessing the channel on the unlicensed spectrum;

The base station sends the preamble signal to the UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.

In the method, when a channel is randomly accessed on an unlicensed spectrum, the base station determines a preamble signal to be transmitted, and the base station accesses the full bandwidth or part of the bandwidth of the channel on the unlicensed spectrum, and the preamble signal is used. Sending to the UE, the LTE system is occupied by the preamble signal on the unlicensed spectrum. Specifically, the time for the LTE-U base station to access the channel is random, or the access time is the starting position of the subframe. However, the base station is not ready to send data. At this time, the placeholder must be sent. The LTE-U base station is occupied by the preamble signal provided in the method, so that the preamble signal can assist the discovery signal to implement the synchronization of the UE. In turn, the LTE system can work on the unlicensed spectrum.

Preferably, the start time of the preamble signal is the time of the base station random access channel, and the termination time of the preamble signal is before the data symbol and the transmission time of the control signaling.

Preferably, the preamble signal is a preamble signal including at least one of the first part, the second part and the third part, wherein the first part has a time length of a non-integer number of orthogonal frequency division multiplexing (OFDM) symbols The length, the length of time of the second part and the third part are all integer multiples of the length of the OFDM symbol.

Preferably, the preamble signal to be transmitted is determined, including:

When the available resources are less than one OFDM symbol, determining that the preamble signal to be transmitted includes only the first part;

When the available resource is greater than or equal to one OFDM symbol, it is determined that the preamble signal to be transmitted includes the second portion.

Preferably, when the preamble signal includes the second part, the second part is composed of one OFDM symbol, and the OFDM symbol is composed of a cyclic prefix CP and two periodic sequences.

Preferably, the preamble signal to be transmitted is determined, including:

When the available resources are less than two OFDM symbols, it is determined that the preamble signal to be transmitted only includes the first part;

When the available resources are greater than or equal to two OFDM symbols, it is determined that the preamble signal to be transmitted includes the second portion.

Preferably, when the preamble signal includes the second part, the second part is composed of two OFDM symbols, wherein each OFDM symbol respectively corresponds to a first cyclic prefix (CP), or two OFDM symbols A second CP is shared, and the length of the first CP is half of the length of the second CP.

Preferably, when the available resource is greater than or equal to one OFDM symbol, the second part of the preamble signal is included The division consists of one OFDM symbol consisting of one cyclic prefix and two periodic sequences;

When the available resource is greater than or equal to two OFDM symbols, the second portion of the preamble signal is composed of two OFDM symbols, wherein the first OFDM symbol is composed of a first cyclic prefix CP and a preset number The periodic sequence consists of a second OFDM symbol consisting of a second CP and two second periodic sequences.

Preferably, when the preamble signal further includes the first portion, the sequence in the first portion is generated based on a sequence in the second portion;

When the preamble further includes the third portion, the sequence in the third portion is generated based on a sequence in the second portion.

Correspondingly, on the UE side, a method for receiving a preamble signal provided by the embodiment of the present application includes:

The UE performs initial synchronization using the discovery signal;

When determining that the preamble signal needs to be detected, the UE detects the preamble signal and performs auxiliary synchronization by using the detected preamble signal, where the preamble signal is a full bandwidth of the base station accessing the channel on the unlicensed spectrum. Or sent on part of the bandwidth.

With this method, the UE performs initial synchronization using the discovery signal, and when determining that the preamble signal needs to be detected, the UE detects the preamble signal and performs auxiliary synchronization using the detected preamble signal, wherein the preamble signal is the base station. Transmitting on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum, so that on the UE side, even if the signal reception is found to be very bad, the preamble signal can be used to implement the synchronization function, and the UE can detect these preamble signals. As to whether the UE detects these preamble signals, whether to use these preamble signals to implement the synchronization function depends on the UE receiving the discovery signal. If the signal reception is found to be good, the preamble signal is a placeholder, and the UE can ignore the direct decoupling control of the preamble signal. Signaling and data are all there.

Preferably, the method further comprises:

The UE determines the data start position using the detected preamble signal.

Preferably, the determining that the UE needs to detect the preamble signal comprises: determining, by the UE, that the preamble signal needs to be detected according to the receiving quality of the discovery signal.

Preferably, the detecting, by the UE, the preamble signal includes:

The UE detects the entirety of the second part of the preamble signal in the received signal by using the locally stored or immediately generated preamble sequence, or detects the first OFDM symbol of the second part of the preamble signal, or the preamble signal The second OFDM symbol of the second part is detected;

If the second part of the preamble signal is not detected, the UE abandons the detection of the preamble signal;

If the second portion of the preamble signal is detected, the UE performs detection of the third portion of the preamble signal.

A transmitting device for a preamble signal provided by the embodiment of the present application includes:

a preamble signal determining unit, configured to determine a preamble signal to be transmitted when the base station randomly accesses the channel on the unlicensed spectrum;

And a sending unit, configured to send the preamble signal to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.

When the device randomly accesses the channel on the unlicensed spectrum, the device determines the preamble signal to be sent, and sends the preamble signal to the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum. The UE, thereby implementing the occupancy of the LTE system on the unlicensed spectrum by using the preamble signal, specifically, the time for the LTE-U base station to access the channel is random, or the access time is the starting position of the subframe, but the base station It is not ready to send data. At this time, the placeholder must be sent. The LTE-U base station uses the preamble signal to occupy the bit, so that the preamble signal can assist the discovery signal to realize the synchronization of the UE. In turn, the LTE system can work on the unlicensed spectrum.

Preferably, the preamble signal is a preamble signal including at least one of the first part, the second part and the third part, wherein the length of the first part is a non-integer number of OFDM symbols, the second part and the third part The length of the part is an integer multiple of the length of the OFDM symbol.

Preferably, when the preamble signal determining unit determines the preamble signal to be transmitted, it is specifically used to:

Preferably, when the preamble signal includes the second part, the second part is composed of two OFDM symbols, wherein each OFDM symbol respectively corresponds to a first cyclic prefix CP, or two OFDM symbols share one The second CP, the length of the first CP is half of the length of the second CP.

Preferably, when the available resource is greater than or equal to one OFDM symbol, the second part of the preamble signal is composed of one OFDM symbol, and the OFDM symbol is composed of one cyclic prefix and two periodic sequences;

A receiving device for a preamble signal provided by the embodiment of the present application includes:

An initial synchronization unit for initial synchronization using the discovery signal;

An auxiliary synchronization unit, configured to detect the preamble signal and perform auxiliary synchronization by using the detected preamble signal when determining that the preamble signal needs to be detected, wherein the preamble signal is that the base station accesses the channel on the unlicensed spectrum Transmitted on full bandwidth or part of the bandwidth.

Through the device, on the UE side, the initial synchronization is performed by using the discovery signal, and when determining that the preamble signal needs to be detected, the UE detects the preamble signal and performs auxiliary synchronization by using the detected preamble signal, where the preamble signal is The base station sends the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum, so that the UE can detect the preamble signal by using the preamble signal even if the signal reception is very bad. The preamble signal, whether the UE is to detect these preamble signals, whether to use these preamble signals to achieve synchronization function depends on the UE receiving the discovery signal. If the signal reception is found to be good, the preamble signal is a placeholder, and the UE can ignore the preamble signal directly. It is enough to solve the control signaling and data.

Preferably, the auxiliary synchronization unit is further configured to: determine a data start position by using the detected preamble signal.

Preferably, when the auxiliary synchronization unit determines that the preamble signal needs to be detected, it is specifically used to: determine that the preamble signal needs to be detected according to the reception quality of the discovery signal.

Preferably, when the auxiliary synchronization unit detects the preamble signal, it is specifically used to:

Detecting the entirety of the second portion of the preamble signal in the received signal using a locally stored or immediately generated preamble sequence, or detecting the first OFDM symbol of the second portion of the preamble signal, or second to the preamble signal Part of the second OFDM symbol is detected;

If the second part of the preamble signal is not detected, the detection of the preamble signal is abandoned;

If the second portion of the detection preamble is completed, the detection of the third portion of the preamble is performed.

On the base station side, another apparatus for transmitting a preamble signal provided by the embodiment of the present application includes:

A processor for reading a program in the memory, performing the following process:

Determining a preamble signal to be transmitted when the base station randomly accesses the channel on the unlicensed spectrum;

The preamble signal is sent by the transceiver 510 to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.

In the device, on the base station side, when the channel is randomly accessed on the unlicensed spectrum, the preamble signal to be transmitted is determined, and the preamble signal is used on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum. Sending to the user equipment UE, the LTE system is occupied by the preamble signal on the unlicensed spectrum. Specifically, the time for the LTE-U base station to access the channel is random, or the access time is the start of the subframe. Location, but the base station is not ready to send data. At this time, the placeholder must be sent. The LTE-U base station is occupied by the preamble signal, so that the preamble signal can assist the discovery signal to realize the synchronization of the UE. In turn, the LTE system can work on the unlicensed spectrum.

Preferably, the start time of the preamble signal is the time when the base station randomly accesses the channel, and the preamble signal The termination time is before the transmission time of the data symbols and control signaling.

Preferably, when the processor determines the preamble signal that needs to be sent, it is specifically used to:

Alternatively, when the processor determines the preamble to be transmitted, it is specifically used to:

A transceiver for receiving and transmitting related information data under the control of a processor.

Preferably, the apparatus further includes a bus architecture, which may include any number of interconnected buses and bridges, specifically linked by one or more processors represented by the processor and various circuits of the memory represented by the memory. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. The transceiver can be a plurality of components, including a transmitter and a transceiver, providing means for communicating with various other devices on a transmission medium.

The processor is responsible for managing the bus architecture and the usual processing, and the memory can store the data that the processor uses when performing operations.

Correspondingly, on the UE side, a receiving device for a preamble signal provided by the embodiment of the present application includes:

Initial synchronization using a discovery signal received through the transceiver;

When it is determined that the preamble signal needs to be detected, the preamble signal received by the transceiver 610 is detected and assisted synchronization is performed by using the detected preamble signal, wherein the preamble signal is the base station accessing the unlicensed spectrum. Transmitted on the full bandwidth or part of the bandwidth of the channel.

Preferably, the processor is further configured to: determine the starting position of the data by using the detected preamble signal.

Preferably, when the processor determines that the preamble signal needs to be detected, it is specifically configured to: determine, according to the receiving quality of the discovery signal, that the preamble signal needs to be detected.

Preferably, when the processor detects the preamble signal, it is specifically used to:

Each of the above units can be implemented by a physical device such as a processor.

Preferably, the device further comprises a bus architecture and a user interface, the bus architecture may comprise any number of interconnected buses and bridges, in particular the various circuits of the memory represented by one or more processors and memories represented by the processor are together. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. The transceiver can be a plurality of components, including a transmitter and a receiver, providing means for communicating with various other devices on a transmission medium. For different user equipments, the user interface may also be an interface capable of externally connecting the required devices, including but not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

DRAWINGS

1 is a schematic diagram of a first type of frame structure used in an FDD system in the prior art;

2 is a schematic diagram of a second type of frame structure used in a TDD system in the prior art;

FIG. 3 is a schematic structural diagram of a preamble according to an embodiment of the present disclosure;

4 is a schematic structural diagram of another preamble signal according to an embodiment of the present application;

FIG. 5 is a schematic flowchart of a method for sending a preamble according to an embodiment of the present disclosure;

FIG. 6 is a schematic flowchart of a method for receiving a preamble according to an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of a device for transmitting a preamble according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of a receiving device for a preamble according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of another apparatus for transmitting a preamble according to an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of another apparatus for receiving a preamble according to an embodiment of the present disclosure.

detailed description

Considering that the placeholder symbol has to be transmitted, the embodiment of the present application provides a new design of the placeholder symbol, that is, the occupancy function is realized by using the newly designed preamble signal, so that the function of the placeholder can be completed and realized. It assists in the discovery of signal synchronization and other functions to solve the problem of network access and cell synchronization encountered by the LTE system on the unlicensed spectrum.

The embodiment of the present application proposes that when a channel is randomly accessed on an unlicensed spectrum, a preamble signal to be transmitted is determined, and a starting point and a length of the preamble signal are adaptively variable, that is, a length and a position of the preamble signal are not preset. The base station transmits the determined preamble signal to the UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum. Therefore, the base station not only implements the LTE-U base station signal occupation by the preamble signal, but also has the functions of assisting the UE synchronization and the like.

The complete preamble signal structure provided in the embodiment of the present application is composed of three parts, and the lengths of the first part (preamble I) and the third part (preamble III) are variable, not fixed length, and the length of the second part (preamble II) It is relatively fixed, and the length of the first part is a non-integer Orthogonal Frequency Division Multiplex (OFDM) symbol length, and the lengths of the second part and the third part are integer multiples of the OFDM symbol. The preamble signal actually transmitted may include only some of the above three parts, and may also include all three parts.

An illustration of three specific scenarios is given below.

Embodiment 1 The time domain structure of the three parts included in the preamble signal that needs to be sent to the UE determined by the base station is as shown in FIG. 3, and the following principles are met:

Preamble II, if present, consists of an OFDM symbol from the time domain, the OFDM symbol being prefixed by a cyclic prefix (CP) consists of two periodic sequences C. The periodic sequence C can be generated by a Pseudo-Noise Sequence (PN) sequence or a zadoff-chu sequence or other sequences having very good correlation properties.

The preamble I is represented by the sequence A, and its length is variable, and the number of samples is |A|, which may be any sequence or part of the preamble II. Preferably, the preamble II sequence is taken according to the length of the preamble I |A| The front |A| or the following |A| of [CP C C] is used as the preamble I. If |A|=0, the preamble I part does not exist.

The preamble III is represented by the sequence D. If it exists, its length must be an integer number of OFDM symbols. Preferably, the repetition of the preamble II sequence [CP C C], the length |D| is determined by the base station, and the repetition can be determined according to the length. The number of OFDM symbols, if |D|=0, the preamble III part does not exist.

That is, the preferred preamble I and preamble III are both generated by the preamble II, and their lengths are adaptively changed.

In this scenario, the determination of the three parts of the preamble follows the following rules:

When the available resources are less than one OFDM symbol, only preamble I is configured;

When the available resources are greater than or equal to one OFDM symbol, the preamble II can be configured;

If there is no preamble II, no preamble III is configured later;

Preamble I and preamble III can be configured or not configured when the preamble II is configured.

The length of the preamble I is variable, but the length of time must be less than two OFDM symbols;

The preamble III, if present, must be an integer multiple of the OFDM symbol.

Since the sequence of the preamble signal has a fixed periodic structure, the UE can recognize the end time of the preamble signal, and can complete the occupancy function of the contention access and enable the UE to complete the synchronization process of time and frequency.

Example 1:

It is assumed that when the base station randomly accesses the channel, it is located in the Mth OFDM symbol of a certain subframe, and on the Nth sample, when a conventional CP is used, M is a positive integer and is less than or equal to 14, and N is a positive integer, and its size Corresponding to the sampling rate.

If M=1, N=1, the base station access time is located at the beginning of a certain subframe. If the base station is ready to send data at this time, the placeholder is not sent, and the preamble I, preamble II, and preamble III are set. The length is 0;

If 13>M>1, N>1, that is, the base station random access time is not the starting position of an OFDM symbol in the subframe, and the access time to the next complete subframe initial position includes at least two complete OFDM symbols. The base station may send the preamble I on the Nth sample of the Mth OFDM symbol to the last sample of the OFDM symbol, and transmit the preamble II on the M+1th OFDM symbol, in the access subframe The preamble III is transmitted from M+1 to the 14th OFDM. In this case, the UE may first detect the preamble II, for example, correlation detection. Since the UE has obtained the coarse synchronization by using the discovery signal, the position of the preamble II is relatively accurate, and then the period characteristic of the preamble II can be used to perform the fractional multiple. Frequency offset estimation, with precise symbol timing. Since preamble III can also be used at this time, the repetitive characteristics of preamble II and preamble III can be used to obtain a more accurate fine synchronization estimation than using only preamble II.

If M=13, N>1, that is, the base station random access time is not the starting position of an OFDM symbol in the subframe, and the access time to the next complete subframe initial position includes only one complete OFDM symbol, then the base station Can be in the Mth The Nth sample of the OFDM symbol transmits preamble I to the last sample of the OFDM symbol, the preamble II is transmitted on the 14th OFDM symbol, and the length of the preamble III is configured to be 0. In this case, the preamble II assisted discovery signal can be used to achieve fine synchronization of the UE.

If M=14, N>1, that is, there is no complete OFDM symbol before the next complete subframe, and the base station can be at the Nth sample of the 14th OFDM symbol to the last sample of the OFDM symbol. Send preamble I without preamble II and preamble III. The preamble II and the preamble III assist in the discovery of the signal for fine synchronization while acting as a placeholder, which can overcome the shortcomings of the use of the discovery signal in the second case, and the base station cannot judge the discovery even if the signal is well received. Whether the signal is well received, the base station can transmit the preamble II and the preamble III, and the UE decides whether to use it for enhanced fine synchronization estimation.

Since the preamble signal can function as a placeholder, preferably, the preamble signal occupies the entire transmission bandwidth, but can also occupy only part of the bandwidth, that is, the base station accesses the full bandwidth or part of the bandwidth of the channel on the unlicensed spectrum. And transmitting the determined preamble signal to the UE.

Implementation 2:

The preamble signal is still composed of three parts, but unlike the above scheme 1, the preamble II occupying one OFDM symbol in scheme one is replaced by the preamble II occupying two OFDM symbols. The preamble II form of two OFDM symbols is [CP1 C1 CP1 C1] or [CP2 C1 C1]. The former adopts the traditional cyclic prefix, that is, the first cyclic prefix CP1, [CP1 C1] constitutes one OFDM symbol, and the latter two OFDM symbols share one cyclic prefix, that is, the second cyclic prefix CP2, wherein the length of CP1 is half of the length of CP2.

Preamble I, if present, is represented by sequence A, the number of samples is |A|, and its length is less than preamble II, that is, less than two OFDM symbol lengths, which may be any sequence, preferably, according to the length of preamble I |A| Take the front |A| or the later |A| samples of the preamble II sequence as preamble I. If |A|=0, the preamble I part does not exist.

The preamble III is represented by the sequence D. If it exists, its length must be an integer number of OFDM symbols. Preferably, the repetition of the preamble II sequence [CP1 C1], the length |D| is determined by the base station, and the OFDM symbol can be determined according to the length thereof. Repeat the number. If |D|=0, the preamble III part does not exist.

In this scenario, the determination (or configuration) of these three parts of the preamble follows the following rules:

When the available resources are less than two OFDM symbols, only preamble I is configured;

When the available resources are greater than or equal to two OFDM symbols, the preamble II can be configured;

If there is no preamble II, no preamble III is configured later;

The length of the preamble I is variable, but the time must be less than two OFDM symbols;

If preamble III is present, its length must be an integer multiple of the OFDM symbol.

Example 2:

Suppose that the base station is located in the Mth OFDM symbol of a certain subframe, the Nth sample, and M=12, when the base station randomly accesses the channel. N>1, that is, the access time is not the starting position of an OFDM symbol in the subframe, and the access time to the next complete subframe initial position includes two complete OFDM symbols, and the base station can be in the 12th OFDM symbol. The Nth sample transmits a preamble I to the last sample of the OFDM symbol, the preamble II is transmitted on the 13th and 14th OFDM symbols, and the length of the preamble III is configured to be 0.

The use of two periodic sequences in preamble II can help the discovery signal to achieve fine synchronization estimation well, which can overcome the shortcomings of the above-mentioned discovery signal in the case of inaccurate synchronization. The function is similar to that of scheme 1.

Embodiment 3: The time domain structure of the three parts included in the preamble signal that needs to be sent to the UE determined by the base station is as shown in FIG. 4, and the following principles are met:

Preamble II, if present, consists of two OFDM symbols from the time domain, the first OFDM symbol consisting of a first cyclic prefix CP1 and a preset number T (T is greater than or equal to 1) time domain periodic sequence B; The OFDM symbols are composed of a second cyclic prefix CP2 and two periodic sequences C, both of which can be generated by a frequency domain PN sequence or a zadoff-chu sequence or other sequences having very good correlation properties. The base station needs to determine the number T of periodic sequences B in advance.

Example 3:

Assuming that the LTE-U system operates in the 5.8G band and the maximum crystal error is 10ppm, the maximum frequency offset is 116K. Considering that the LTE-U system works in the same environment as WiFi and does not support high-speed mobile, its maximum Doppler frequency. The shift is much smaller than 1K, and the subcarrier spacing is 15K, so the maximum normalized frequency offset is 7.8, and the estimated range of the integer multiple of the T periodic sequence B is T/2, so the number of periodic sequences B can be determined. For T=16, if the crystal error of the LTE system can be reduced to 5 ppm, then T=8, which can be determined according to the current industry level.

The preamble I is represented by the sequence A, and its length is variable. The number of samples is |A|, which may be any sequence, or may be part of the preamble II. Preferably, according to the length of the preamble I |A| The front |A| or the following |A| samples of the second OFDM symbol sequence [CP2 C C] are used as preamble I, and if |A|=0, the preamble I portion does not exist.

The preamble III is represented by the sequence D. If it exists, its length must be an integer number of OFDM symbols. Preferably, it may be a repetition of the second OFDM symbol sequence [CP2 C C] of the preamble II, and the length |D| is determined by the base station. The number of repetitions of the OFDM symbol can be determined according to the length. If |D|=0, the preamble III portion does not exist.

When the available resource is greater than or equal to one OFDM symbol, the second OFDM symbol [CP2 C C] of the preamble II may be configured;

When the available resources are greater than or equal to two OFDM symbols, the complete preamble II can be configured;

If there is no or no complete preamble II, no preamble III is configured behind;

The preamble I has a variable length and is not fixed, but the length of time is necessarily less than one OFDM symbol;

The preamble III, if present, must be an integer multiple of the OFDM symbol time.

Example 4:

Suppose that when the base station accesses the channel, it is located in the Mth OFDM symbol of a certain subframe. On the Nth sample, when the conventional CP is used, M is a positive integer and is less than or equal to 14, and N is a positive integer. Rate related.

If M=1, N=1, the base station random access time is located at the beginning of a subframe. If the base station is ready to send data at this time, there is no need to send a placeholder, and preamble I and preamble II can be set. The length of the preamble III is 0;

If M=12, N>1, that is, the base station random access time is not the starting position of an OFDM symbol in the subframe, and the access time to the next complete subframe initial position includes at least two complete OFDM symbols, the base station The preamble I may be transmitted on the Nth sample of the Mth OFDM symbol to the last sample of the OFDM symbol, and the preamble II may be transmitted on the M+1th and M+2th OFDM symbols. In this case, the UE may first detect the periodic sequence B in the first OFDM symbol of the preamble II, obtain the coarse time and frequency synchronization by using the sequence B, and then obtain the small periodic sequence C of the second OFDM symbol of the preamble II to obtain a small Several times the frequency offset estimation, with precise symbol timing.

If M<12, N>1, at least three complete OFDM symbols are included, and the base station may send the preamble I on the Nth sample of the Mth OFDM symbol to the last sample of the OFDM symbol. The preamble II is transmitted on the M+1 and the M+2 OFDM symbols, and the preamble III is transmitted in the M+3 to the last available OFDM symbol. Similarly, the sequence B is used to obtain the coarse time and frequency synchronization. Since the preamble III exists at this time, the preamble III can be used as the second OFDM symbol repetition feature of the preamble II, and the preamble II and the preamble III are combined to obtain only the preamble II. More accurate fine synchronization estimation. Since the coarse synchronization can be realized by the periodic sequence B, it is possible to overcome the scenario in which the above-mentioned situation 3 finds that the signal is invalid.

When M=13, N>1, there is only one complete OFDM symbol available. In this case, the base station first transmits the preamble I on the Nth sample of the 13th OFDM symbol to the last sample of the OFDM symbol. And then transmitting the second OFDM symbol [CP2 C C] of the preamble II on the 14th OFDM symbol, and then degenerates to the special case of the first scheme, and the OFDM symbol can be used to obtain the fractional multiple offset estimation and the exact symbol. Timing, overcomes the shortcomings of the previously found discovery signal in the case of two-in-one synchronization inaccuracy.

The base station can configure the preamble signal of the structure shown in FIG. 4, and the UE can decide whether to use the preamble signal to implement coarse synchronization and fine synchronization. Since the preamble signal provided by the embodiment of the present application is capable of occupying a placeholder function, a preferred preamble signal occupies the entire transmission bandwidth, but may also occupy only part of the bandwidth, that is, the base station accesses the channel on the unlicensed spectrum. The determined preamble signal is sent to the UE on the bandwidth or part of the bandwidth.

In the foregoing embodiment, the OFDM number from the time when the base station randomly accesses the channel to the next complete subframe is used to transmit the preamble as a placeholder, in fact, the part of the subframe in which the base station randomly accesses the channel. The OFDM symbol, if it can be used for transmitting data, the solution of the embodiment of the present application is also applicable, and the base station configures the last OFDM symbol of the preamble signal. Preferably, the OFDM symbol is before the data OFDM symbol or with the first data OFDM symbol. coincide. At this time, the preamble signal can also realize the auxiliary discovery signal synchronization while indicating the start position of the data symbol while completing the placeholder function.

Example 5:

Assume that the base station accesses the channel when the Mth OFDM symbol of the certain subframe, the Nth sample, and M=2, N>1, that is, the access time is not the starting position of an OFDM symbol in the subframe, And with a conventional CP, in addition to the first and second OFDM symbols, there are 12 full OFDM symbols available. If the base station is configured to use 12 OFDM symbols after the access time for transmitting data and signaling, send the preamble I on the Nth sample of the second OFDM symbol to the last sample of the OFDM symbol. If the base station wants to use 11 OFDM symbols after the access time for transmitting data and signaling, the preamble II may be sent on the third OFDM symbol, and the Nth sample of the second OFDM symbol is used. The preamble I is sent on the last sample of the OFDM symbol.

In summary, referring to FIG. 5, a method for transmitting a preamble signal according to an embodiment of the present application includes:

S101. When a base station randomly accesses a channel on an unlicensed spectrum, determining, by the base station, a preamble signal to be sent;

S102. The base station sends the preamble signal to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.

In the method, when a channel is randomly accessed on an unlicensed spectrum, the base station determines a preamble signal to be transmitted, and the base station accesses the full bandwidth or part of the bandwidth of the channel on the unlicensed spectrum, and the preamble signal is used. Sending to the user equipment UE, the LTE system is occupied by the preamble signal on the unlicensed spectrum. Specifically, the time for the LTE-U base station to access the channel is random, or the access time is the start of the subframe. Location, but the base station is not ready to send data. At this time, the placeholder must be sent. The LTE-U base station is occupied by the preamble signal provided in the method, so that the preamble signal can assist the discovery signal to implement the synchronization of the UE and the like. In turn, the LTE system can work on the unlicensed spectrum.

Preferably, the preamble signal is a preamble signal including at least one of the first part, the second part, and the third part, wherein the length of the first part is a non-integer number of orthogonal frequency division multiplexing OFDM symbol lengths, The length of time of the second part and the third part is an integer multiple of the length of the OFDM symbol.

Preferably, the preamble signal to be transmitted is determined, including:

Correspondingly, on the UE side, referring to FIG. 6, a method for receiving a preamble signal according to an embodiment of the present application includes:

S201. The user equipment UE performs initial synchronization by using a discovery signal.

S202. When determining that the preamble signal needs to be detected, the UE detects the preamble signal and performs auxiliary synchronization by using the detected preamble signal, where the preamble signal is that the base station accesses a channel on an unlicensed spectrum. Transmitted on full bandwidth or part of the bandwidth.

Preferably, the method further comprises:

The UE determines the data start position using the detected preamble signal.

Preferably, the detecting, by the UE, the preamble signal includes:

For example, on the UE side, a method for receiving a preamble signal includes:

Step 1: The UE uses the discovery signal to perform initial synchronization estimation;

Step 2: The UE determines whether to detect the preamble signal according to the reception quality of the discovery signal; for example, if the reception quality of the signal is found to be good (the specific judgment standard can be set according to actual needs), accurate synchronization can be realized without further detecting the preamble signal. Then, the preamble signal is not detected, and only the preamble signal is used as a placeholder. If the reception quality of the signal is found to be poor, it is determined that the preamble signal needs to be detected.

Step 3: When it is determined that the preamble signal needs to be detected, the UE starts to detect the preamble signal. First, the UE detects the OFDM symbol of the preamble II or the preamble II in the received signal by using the preamble sequence generated by the UE locally or generated in real time. In the first scheme, the entire preamble II is detected. If the second scheme is used, the first OFDM symbol of the preamble II is detected. If the third scheme is used, the second OFDM symbol of the preamble II is detected. Can be related detection.

Further, the detection of the preamble II is completed according to the actual situation of various schemes. If the preamble II is not detected, it means that there is at most preamble I, and the time-frequency synchronization needs to be completed according to the synchronization method of the discovery signal.

Step 4: After the UE completes the preamble II test, it needs to detect whether the preamble III exists according to the preamble III structure according to the actual preamble scheme (the first scheme, the second scheme or the third scheme); the front part of the preamble II is the preamble I. The preamble I is used for the placeholder, and the UE does not need to identify it.

Step 5: After detecting the preamble signal, the UE determines whether to use the preamble signal for auxiliary synchronization according to the structure of the preamble signal and the quality of the UE discovery signal reception. If auxiliary synchronization is needed, the preamble signal is used for auxiliary synchronization.

Step 6: After the UE detects the preamble signal, when the data transmission is an incomplete subframe, the preamble signal is used to determine the starting OFDM symbol position of the data transmission.

Corresponding to the foregoing method, referring to FIG. 7, on the base station side, a transmitting device for transmitting a preamble according to an embodiment of the present application includes:

The preamble signal determining unit 11 is configured to determine, when the base station randomly accesses the channel on the unlicensed spectrum, the preamble signal that needs to be sent;

The sending unit 12 is configured to send the preamble signal to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.

In the device, on the base station side, when the channel is randomly accessed on the unlicensed spectrum, the preamble signal to be transmitted is determined, Transmitting the preamble signal to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum, so as to implement the LTE system occupying the unlicensed spectrum by using the preamble signal, specifically, LTE- The time at which the U base station accesses the channel is random, or the access time is the start position of the subframe, but the base station is not ready to transmit data, and the placeholder must be sent at this time, and the LTE-U base station uses the preamble signal to The placeholder enables the preamble signal to assist the discovery signal to implement functions such as synchronization of the UE. In turn, the LTE system can work on the unlicensed spectrum.

Preferably, the transmitting device of the foregoing preamble signal may be a base station.

Correspondingly, on the UE side, referring to FIG. 8, a receiving device for a preamble signal according to an embodiment of the present application includes:

An initial synchronization unit 21, configured to perform initial synchronization by using a discovery signal;

The auxiliary synchronization unit 22 is configured to: when determining that the preamble signal needs to be detected, detect the preamble signal and perform auxiliary synchronization by using the detected preamble signal, where the preamble signal is the base station accessing the unlicensed spectrum Transmitted on the full bandwidth or part of the bandwidth of the channel.

Preferably, the receiving device of the foregoing preamble signal may be a UE.

Referring to FIG. 9, on the base station side, a sending device for a preamble signal (the device may be a base station) provided by the embodiment of the present application includes:

The processor 500 is configured to read a program in the memory 520 and perform the following process:

Preferably, when the processor 500 determines the preamble signal that needs to be sent, it is specifically used to:

Alternatively, when the processor 500 determines the preamble signal that needs to be transmitted, it is specifically used to:

The transceiver 510 is configured to receive and transmit related information data under the control of the processor 500.

Here, in FIG. 7, the bus architecture may include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 500 and various circuits of memory represented by memory 520. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. Transceiver 510 can be a plurality of components, including a transmitter and a transceiver, providing means for communicating with various other devices on a transmission medium.

The processor 500 is responsible for managing the bus architecture and the usual processing, and the memory 520 can store the processor 500 for execution. The data used during the operation.

Correspondingly, on the UE side, referring to FIG. 10, a receiving device (which may be a UE) of the preamble signal provided by the embodiment of the present application includes:

The processor 600 is configured to read a program in the memory 620 and perform the following process:

Initial synchronization is performed using the discovery signal received through the transceiver 610;

Preferably, the processor 600 is further configured to: determine a data start position by using the detected preamble signal.

Preferably, when the processor 600 determines that the preamble signal needs to be detected, it is specifically used to: determine that the preamble signal needs to be detected according to the reception quality of the discovery signal.

Preferably, when the processor 600 detects the preamble signal, it is specifically used to:

The transceiver 610 is configured to receive and transmit related information data under the control of the processor 600.

Here, in FIG. 8, the bus architecture may include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 600 and various circuits of memory represented by memory 620. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. Transceiver 610 can be a plurality of components, including a transmitter and a receiver, providing means for communicating with various other devices on a transmission medium. For different user equipments, the user interface 630 may also be an interface capable of externally connecting the required devices, including but not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

The processor 600 is responsible for managing the bus architecture and general processing, and the memory 620 can store data used by the processor 600 in performing operations.

In summary, in the embodiment of the present application, the time for the LTE-U base station to access the channel is random, or the access time is the starting position of the subframe, but the base station is not ready to send data, and The placeholder is sent. The embodiment of the present application implements the placeholder by appropriately designing the preamble signal, so that it can assist the discovery signal to achieve synchronization and the like.

The feature of the placeholder signal is divided into two parts, one part is a non-integer number of OFDM symbols, and the other part is an integer number of OFDM symbols, and the ending position depends on the configuration of the base station. If the incomplete subframe does not transmit data, the placeholder end position Before the next subframe, if the data is transmitted in an incomplete subframe, the end position of the place signal is an OFDM symbol of the subframe in which the access time configured by the base station is located. The placeholder signal can be of any structure. Since the placeholder is necessary, the structure of the placeholder can be properly designed so that the preamble signal and the transmission schemes one, two, and three have the function of assisting synchronization, and play in the first scheme. The end point of the synchronization action is the preamble II of one OFDM symbol. The preamble I only has a placeholder function, and there is no other use. The preamble III needs to count the number of OFDM symbols occupied by the actual needs, and the base station determines whether there are any symbols or not. It is detected that if the preamble III is also present, the preamble II combined with the preamble III can make the synchronization estimation more accurate. The second scheme is the same as the scheme one, except that the preamble II in scheme 1 is replaced by two OFDM symbols, because it is also possible to switch to two OFDM symbols, and better synchronization estimation accuracy can be obtained, but the preamble II needs at least two. OFDM symbols, the overhead is large; the focus of the third scheme is that the preamble II's previous symbol can achieve coarse synchronization, the latter symbol can achieve fine synchronization, but its structure is very flexible, when the number of symbols required by the placeholder is small, Fine synchronization can be implemented only by configuring its second OFDM symbol. When there are many placeholder symbols, coarse synchronization can be implemented by the first symbol of preamble II. In this case, the discovery signal is replaced even if signal reception is found. Very bad, can also use it to achieve synchronization function, the UE can detect these preamble signals, as to whether the UE is to detect, whether to use it to achieve synchronization function depends on the UE receiving the discovery signal, if the signal is found to be good, the preamble signal It is a placeholder, and the UE is designed according to the LTE-U scheme. It ignores the direct control of the signaling and data for the preamble. To the.

In summary, the embodiment of the present application proposes a novel transmission method and device for a preamble signal, which can assist in synchronization while the preamble signal plays a role of occupying a bit, and assists in identifying the starting position of data transmission, but the prior art has not yet given The specific implementation of the bit.

Those skilled in the art will appreciate that embodiments of the present application can be provided as a method, system, or computer program product. Thus, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment in combination of software and hardware. Moreover, the application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the present application. It should be understood that each flow in the flowchart and/or block diagram can be implemented by computer program instructions. Combinations of blocks and/or blocks, and flow diagrams and/or blocks in the flowcharts and/or block diagrams. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

It will be apparent to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit and scope of the application. Thus, it is intended that the present invention cover the modifications and variations of the present invention.

Claims

A method for transmitting a preamble signal, the method comprising:

The base station determines a preamble signal to be transmitted when randomly accessing the channel on the unlicensed spectrum;

The base station sends the preamble signal to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.
The method according to claim 1, wherein a start time of the preamble signal is a time of the base station random access channel, and a termination time of the preamble signal is before a data symbol and a control signal transmission time .
The method according to claim 1, wherein said preamble signal is a preamble signal including at least one of a first portion, a second portion, and a third portion, wherein a length of time of the first portion is a non-integer number of positive The frequency division is divided into OFDM symbol lengths, and the lengths of the second part and the third part are integer multiples of the OFDM symbol length.
The method according to claim 3, wherein determining the preamble signal to be transmitted comprises:

When the available resources are less than one OFDM symbol, determining that the preamble signal to be transmitted includes only the first part;

When the available resource is greater than or equal to one OFDM symbol, it is determined that the preamble signal to be transmitted includes the second portion.
The method according to claim 4, wherein when said preamble signal comprises said second portion, said second portion consists of an OFDM symbol consisting of a cyclic prefix CP and two periodic sequences.
The method according to claim 3, wherein determining the preamble signal to be transmitted comprises:

When the available resources are less than two OFDM symbols, it is determined that the preamble signal to be transmitted only includes the first part;

When the available resources are greater than or equal to two OFDM symbols, it is determined that the preamble signal to be transmitted includes the second portion.
The method according to claim 6, wherein when the preamble signal comprises the second part, the second part is composed of two OFDM symbols, wherein each OFDM symbol respectively corresponds to a first cyclic prefix CP Or, the two OFDM symbols share a second CP, and the length of the first CP is half of the length of the second CP.
The method according to claim 4, wherein when the available resource is greater than or equal to one OFDM symbol, the second portion of the preamble signal is composed of one OFDM symbol, the OFDM symbol consists of a cyclic prefix and two Periodic sequence composition;

When the available resource is greater than or equal to two OFDM symbols, the second portion of the preamble signal is composed of two OFDM symbols, wherein the first OFDM symbol is composed of a first cyclic prefix CP and a preset number The periodic sequence consists of a second OFDM symbol consisting of a second CP and two second periodic sequences.
The method according to claim 5, 7 or 8, wherein when said preamble further comprises said first portion, said sequence in said first portion is generated based on a sequence in said second portion;

When the preamble further includes the third portion, the sequence in the third portion is based on the second portion The sequence generated in .
A method for receiving a preamble signal, the method comprising:

The user equipment UE performs initial synchronization by using the discovery signal;

When determining that the preamble signal needs to be detected, the UE detects the preamble signal and performs auxiliary synchronization by using the detected preamble signal, where the preamble signal is a full bandwidth of the base station accessing the channel on the unlicensed spectrum. Or sent on part of the bandwidth.
The method of claim 10, further comprising:

The UE determines the data start position using the detected preamble signal.
The method according to claim 10 or 11, wherein the UE determines that the preamble signal needs to be detected, and the UE determines that the preamble signal needs to be detected according to the reception quality of the discovery signal.
The method according to claim 10, wherein the detecting, by the UE, the preamble signal comprises:

The UE detects the entirety of the second part of the preamble signal in the received signal by using the locally stored or immediately generated preamble sequence, or detects the first OFDM symbol of the second part of the preamble signal, or the preamble signal The second OFDM symbol of the second part is detected;

If the second part of the preamble signal is not detected, the UE abandons the detection of the preamble signal;

If the second portion of the preamble signal is detected, the UE performs detection of the third portion of the preamble signal.
A transmitting device for a preamble signal, characterized in that the device comprises:

a preamble signal determining unit, configured to determine a preamble signal to be transmitted when the base station randomly accesses the channel on the unlicensed spectrum;

And a sending unit, configured to send the preamble signal to the user equipment UE on the full bandwidth or part of the bandwidth of the access channel on the unlicensed spectrum.
The device according to claim 14, wherein a start time of the preamble signal is a time of the base station random access channel, and a termination time of the preamble signal is before a data symbol and a control signal transmission time .
The apparatus according to claim 14, wherein said preamble signal is a preamble signal including at least one of a first portion, a second portion, and a third portion, wherein a length of time of said first portion is a non-integer number of positive The frequency division is divided into OFDM symbol lengths, and the lengths of the second part and the third part are integer multiples of the OFDM symbol length.
The device according to claim 16, wherein when the preamble determining unit determines the preamble signal to be transmitted, it is specifically used to:

When the available resources are less than one OFDM symbol, determining that the preamble signal to be transmitted includes only the first part;

When the available resource is greater than or equal to one OFDM symbol, it is determined that the preamble signal to be transmitted includes the second portion.
The apparatus according to claim 17, wherein when said preamble signal comprises said second portion, said second portion consists of an OFDM symbol consisting of a cyclic prefix CP and two periodic sequences.
The device according to claim 16, wherein when the preamble determining unit determines the preamble signal to be transmitted, it is specifically used to:

When the available resources are less than two OFDM symbols, it is determined that the preamble signal to be transmitted only includes the first part;

When the available resources are greater than or equal to two OFDM symbols, it is determined that the preamble signal to be transmitted includes the second portion.
The apparatus according to claim 19, wherein when said preamble signal comprises said second portion, said second portion is composed of two OFDM symbols, wherein each OFDM symbol corresponds to a first cyclic prefix CP Or, the two OFDM symbols share a second CP, and the length of the first CP is half of the length of the second CP.
The apparatus according to claim 17, wherein when the available resource is greater than or equal to one OFDM symbol, the second portion of the preamble signal comprises an OFDM symbol consisting of a cyclic prefix and two Periodic sequence composition;

When the available resource is greater than or equal to two OFDM symbols, the second portion of the preamble signal is composed of two OFDM symbols, wherein the first OFDM symbol is composed of a first cyclic prefix CP and a preset number The periodic sequence consists of a second OFDM symbol consisting of a second CP and two second periodic sequences.
The apparatus according to claim 18, 20 or 21, wherein when said preamble further comprises said first portion, said sequence in said first portion is generated based on a sequence in said second portion;

When the preamble further includes the third portion, the sequence in the third portion is generated based on a sequence in the second portion.
A receiving device for a preamble signal, characterized in that the device comprises:

An initial synchronization unit for initial synchronization using the discovery signal;

An auxiliary synchronization unit, configured to detect the preamble signal and perform auxiliary synchronization by using the detected preamble signal when determining that the preamble signal needs to be detected, wherein the preamble signal is that the base station accesses the channel on the unlicensed spectrum Transmitted on full bandwidth or part of the bandwidth.
The device according to claim 23, wherein the auxiliary synchronization unit is further configured to: determine a data start position by using the detected preamble signal.
The device according to claim 23 or 24, wherein the auxiliary synchronization unit determines that the preamble signal needs to be detected, and is specifically configured to: determine that the preamble signal needs to be detected according to the reception quality of the discovery signal.
The device according to claim 23, wherein when the auxiliary synchronization unit detects the preamble signal, specifically:

Detecting the entirety of the second portion of the preamble signal in the received signal using a locally stored or immediately generated preamble sequence, or detecting the first OFDM symbol of the second portion of the preamble signal, or second to the preamble signal Part of the second OFDM symbol is detected;

If the second part of the preamble signal is not detected, the detection of the preamble signal is abandoned;

If the second portion of the detection preamble is completed, the detection of the third portion of the preamble is performed.