WO2016169399A1 - Data transmission method - Google Patents

Abstract

A data transmission method, comprising: a station determining a parameter of a frame in an unauthorized carrier, wherein the structure of the frame comprises: a listen region for detecting whether a subframe in the frame is in an idle state and a data transmission region for data transmission; and the parameter comprises at least one of the following: a frame period, a clear channel assessment (CCA) period, an orthogonal frequency division multiplexing (OFDM) symbol location from which CCA starts, a CCA duration, a CCA threshold, the duration of the listen region, the duration of the data transmission region, a random rollback value of enhanced clear channel assessment (eCCA), a random rollback window length, a silence time period, and a time when data transmission ends.

Description

Method for data transmission Technical field

This document relates to, but is not limited to, wireless communication technology, and more particularly to a method of data transmission.

Background technique

In the evolution of the Long Term Evolution (LTE), the LTE Release 13 protocol (LTE Rel-13) began its research in September 2014. One of the important contents is that the LTE system works with unlicensed carriers. An unlicensed carrier, that is, an unlicensed spectrum, refers to a spectrum or carrier that can be used directly without authorization, such as the current 5 GHz band, in the case of meeting the relevant regulations (radio control) of a government department (such as the National Radio Regulatory Commission). Belong to an unlicensed carrier. This technology will enable the LTE system to use the existing unlicensed carriers, thereby greatly increasing the potential spectrum resources of the LTE system, enabling the LTE system to obtain lower spectrum costs.

However, LTE systems face many problems when using unlicensed carriers. First, in some countries and regions, there are corresponding regulatory policies for the use of unlicensed spectrum. For example, in Europe, if the LTE system operates in an unlicensed carrier, it needs to support the Listen Before Talk (LBT) mechanism, that is, the Clear Channel Assessment (CCA) or extended idle before the data is transmitted. The eCCA refers to the continuous CCA after the CCA is unsuccessful. The number of random retreats is the default value. The two policies under the LBT mechanism are further given in the control policy. The structure needs to support data transmission, which is Frame-Based Equipment (FBE) and Load-Based Equipment (LBE). For details, refer to the European Telecommunications Standards Institute (European Telecommunications Standards Institute). ETSI) specifies the content of Section 4.9 of ETSI EN 301 893 V1.7.1 (2012-06). For the FBE mode, the location of the Clear Channel Assessment (CCA) is fixed every time, so the timing is easy, and the same carrier's site can achieve the same frequency reuse through deployment. Moreover, the duration of each transmission is also fixed, and there is no need to randomly roll back. For the LBE mode, the location of the CCA every time the site can start from any time, as long as there is load, you can start to perform CCA, and the transmission time is as long as It can be randomly determined according to the load size within the maximum occupation time, but multi-site or multi-user frequency reuse is more difficult in this way.

At present, when multiple sites deployed by different operators of the same system operate in an unlicensed carrier frequency band, there are the following problems: if the two sites with similar LTE geographical locations are synchronized, if the CCA time is selected or the eCCA is selected The time and the number of random backoffs are the same. At the same time, when the channel is idle and the data is sent, the transmission collision will cause serious interference. For the case where the two sites are not synchronized, if two sites use the same FBE frame period, one site will always occupy. Another site has been unfairly unfair.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

The embodiment of the invention provides a data transmission method, which solves the problem of avoiding transmission collision between different stations when the LTE system operates in an unlicensed carrier frequency band and the unfair access problem, and improves the spectrum efficiency.

An embodiment of the present invention provides a data transmission method, where the method includes:

The station determines parameters of frames in the unlicensed carrier;

The structure of the frame includes: a listening area for detecting whether a subframe in the frame is in an idle state, and a data transmission area for transmitting data; the parameters of the frame include at least one of: a frame period, The idle channel evaluates the period of the CCA, the OFDM symbol position of the CCA starting, the duration of the CCA, the CCA threshold, the duration of the listening area, the duration of the data transmission area, and the random back of the extended idle channel evaluation eCCA. Depreciation, window length for random backoff, silence time, and time to stop data transmission.

Optionally, the method further includes:

The station adjusts the parameters according to a preset rule.

Optionally, the adjusting, by the site according to the preset rule, the parameter includes:

When the other stations succeed in performing N1 times of CCA continuously or cumulatively according to the frame device FBE mode within a preset time, and N1 is a preset value determined by the station according to the occupied duration, the site is configured according to the preset value. Adjust the parameters in any of the following ways:

Modifying the parameters of the FBE mode by the site; or

The site performs eCCA; or,

The station increases the window length of the random backoff by T unit time, where the unit time includes: a duration of one CCA, a duration of one eCCA, or a duration of N OFDM symbols, where N and T are positive integers; or ,

The station extends the length of the CCA and the eCCA by N said unit time, where N is a positive integer; or

The station stops transmitting for a period of time.

Optionally, the parameters for modifying the FBE mode by the site include:

The site increases the duration of the frame period; or,

The site increases the duration of the CCA; or,

The site increases the period of the CCA; or,

The site lowers the CCA threshold, or,

The site increases the length of the listening zone.

Optionally, the adjusting, by the site according to the preset rule, the parameter includes:

When the site fails to perform N2 times of CCA continuously or cumulatively according to the FBE mode within a preset time, and N2 is a preset value determined by the station according to the occupied duration, the station adjusts the parameter according to any one of the following manners:

Modifying the parameters of the FBE mode by the site; or

The site modifying the random backoff value; or,

The station shortens the window length of the random backoff by P unit time, and the unit time includes: a duration of one CCA, a duration of one eCCA, or a duration of N OFDM symbols, where N and P are positive integers; or

The station shortens the length of the CCA and the eCCA by M said unit time, and M is a positive integer.

Optionally, the parameters for modifying the FBE mode by the site include:

The station shortens the duration of the frame period; or,

The site shortens the duration of the CCA; or,

The site shortens the period of the CCA; or,

The site increases the CCA threshold, or,

The site shortens the length of the listening zone.

Optionally, the method further includes:

The site negotiates with other sites through an air interface or a preset interface, and adjusts the parameters according to the information of the interaction negotiation.

Optionally, the information about the interaction negotiation includes:

The load information or the occupation time of the site, the parameter configuration information of the site in the FBE mode, or the parameter information of the site resource competition.

Optionally, the method further includes:

When the station needs to use an unlicensed carrier to transmit data, the detecting whether the unlicensed carrier is in an idle state includes:

The station performs CCA once in each of the frame periods, and the starting position of the CCA is selected by the station in a preset time window; or

The station performs an eCCA once in each of the frame periods, wherein the eCCA includes a continuous random X times CCA, X is a positive integer, and the start position of the eCCA and the value of X are selected by the station.

Optionally, the preset time window is one time slot or one subframe; the duration of each CCA in the eCCA is the same as the duration of the first CCA, or the duration of the CCA of the eCCA is 1/Z. The duration of the OFDM symbol, Z is a positive integer.

Optionally, the method further includes:

When the location of the data transmission is fixed, the station sends an initial signal before transmitting the data after performing the CCA success, and the initial signal includes at least one of the following information:

Information for notifying other stations that belong to the same operator as the same site to multiplex unlicensed carriers, information for notifying the UE to which the station belongs to multiplex unlicensed carriers, and for notifying other Information about the duration of the unlicensed carrier of the site.

Optionally, the data transmission area is configured to transmit at least one of the following data: user data, control information, reference signals or sequences for measuring or synchronizing or occupying functions, and system message related information.

Optionally, the number of uplink subframes or downlink subframes included in the data transmission area is dynamically adjusted.

Optionally, the quiet time of different sites or the time of stopping data transmission is different.

Optionally, the method further includes:

The station adjusts the parameters based on the results of the statistical CCA.

Optionally, the adjusted parameter is used to control a site access probability and/or occupation time of the spectrum.

Optionally, when the site is a user equipment UE and the UE needs to transmit uplink data, the determining, by the station, the parameters of the frame in the unlicensed carrier includes:

Determining, by the UE, the parameter, and reporting the parameter to a base station to which the UE belongs;

Optionally, the reporting the parameter to the base station to which the UE belongs includes:

The UE sends uplink control information UCI to the base station by using an authorized carrier or a contending unlicensed carrier, where the UCI includes the parameter.

Optionally, when the site performs the CCA for the uplink data transmission by the user equipment UE, the determining, by the station, the parameters of the frame in the unlicensed carrier includes:

The base station to which the UE belongs configures the parameter and sends the parameter to the UE.

Optionally, the sending, by the base station to which the UE belongs, the parameter to the UE includes:

The base station determines, according to the buffer status report BSR and the authorized carrier resource, the UE that is scheduled to be in the same subframe, and sends the parameter to the UE.

The embodiment of the invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the above method.

An embodiment of the present invention provides a method for data transmission, including: determining, by a station, a parameter of a frame in an unlicensed carrier; wherein the frame structure includes: detecting, by the frame, whether a subframe in the frame is in an idle state a listening area and a data transmission area for transmitting data; the parameters include at least one of: a frame period, a period of an idle channel evaluation CCA, an orthogonal frequency division multiplexing OFDM symbol position starting from a CCA, a duration of a CCA, a CCA threshold, The length of the listening area, the duration of the data transmission area, the random backoff value of the extended idle channel evaluation eCCA, the window length of the random backoff, the silence time, and the time at which the data transmission is stopped. The solution provided by the embodiment of the present invention can solve the problem of transmission collision between different sites in the operation of the unlicensed carrier frequency band and the unfair access problem, and improve the spectrum efficiency.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic flowchart of a data transmission method according to an embodiment of the present invention;

2 is a schematic structural diagram of a frame provided by an embodiment of the present invention;

3 is a schematic diagram of an LBT mechanism of an FBE according to an embodiment of the present invention;

4 is a schematic diagram of an LBT mechanism of an LBE according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a random back-off mode 1 according to Embodiment 1 of the present invention; FIG.

FIG. 6 is a schematic structural diagram of a random backoff mode 2 according to Embodiment 1 of the present invention;

7 is a schematic diagram of site resource competition and data transmission in Embodiment 2 of the present invention;

FIG. 8 is a schematic diagram of an LBT mechanism for adjusting a FBE blank area by a station according to Embodiment 5 of the present invention; FIG.

9 is a schematic diagram of a transmission mechanism of uplink and downlink subframes under LBT according to Embodiment 6 of the present invention;

10 is a schematic diagram of an uplink transmission mechanism of two UEs according to Embodiment 6 of the present invention;

11 is a schematic diagram of a method for limiting station transmission in Embodiment 7 of the present invention;

12 is a flowchart of implementing a UE side according to an embodiment of the present invention;

FIG. 13 is a flowchart of implementing a base station side according to Embodiment 11 of the present invention.

Embodiments of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

The steps illustrated in the flowchart of the figures may be executed in a computer system such as a set of computer executable instructions. Also, although logical sequences are shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than the ones described herein.

The station in the embodiment of the present invention may be a base station (Node B), an evolved base station (eNode B), a home base station (Home Node B), a relay station (Relay Node, RN), a user equipment (User Equipment, UE), and the like. A device that is not an authorized carrier.

Clear Channel Assessment (CCA) or extended clear channel assessment (eCCA) means that in a wireless communication system, when a station needs to transmit data on a certain carrier, it first performs detection on the carrier. If, after a given time, no other station is found to send data on this carrier, it starts to transmit (that is, the CCA is successfully executed, and the right to use the carrier is obtained); if other stations are found to be transmitting data, the random avoidance is performed. Retry the process again after a while. The method can effectively avoid collisions on the wireless channel, which is also called Carrier Sense Multiple Access with Conflict Avoidance (CSMA/CA).

An embodiment of the present invention provides a data transmission method. As shown in FIG. 1 , the method includes:

The station determines the parameters of the frames in the unlicensed carrier.

The structure of the frame includes: a listening area for detecting whether a subframe in the frame is in an idle state, and a data transmission area for transmitting data, where the frame structure is as shown in FIG. 2;

The parameter includes at least one of: a frame period, a period of an idle channel evaluation CCA, an Orthogonal Frequency Division Multiplexing (OFDM) symbol position starting from a CCA, a duration of a CCA, a CCA threshold, and the listening area. The duration, the duration of the data transmission area, the extended idle channel evaluation eCCA random backoff value, the random backoff window length, the silence time, and the time at which the data transmission is stopped.

Optionally, the parameters can be adjusted according to actual needs. Data transmission area The number of uplink subframes or downlink subframes included in the domain is dynamically adjusted. The silence time in the corresponding frame of different sites or the time of stopping data transmission may be different, and may be selected as needed.

The data transmission area is configured to transmit at least one of the following data: user data, control information, reference signals or sequences for measuring or synchronizing or occupying functions, and system message related information.

Alternatively, the site can adjust the parameters in one of the following ways.

Manner 1: The site adjusts the parameter according to a preset rule.

Manner 2: The site negotiates with other sites through an air interface or a preset interface, and adjusts the parameter according to the information of the interaction negotiation.

Mode 3: The station adjusts the parameter according to the result of the statistical CCA.

Optionally, for mode 1, the determining, by the site according to the preset rule, the parameter includes:

While other sites in accordance with FBE continuous or accumulated execution times N ₁ CCA success within the preset time, N ₁ is the length of the station according to the determined predetermined value when occupied, the adjustment station according to the following ways parameter:

Modifying the parameters of the FBE mode by the site; or

The site performs eCCA; or,

The station increases the window length of the random backoff by T unit time, where the unit time includes: a duration of one CCA, a duration of one eCCA, or a duration of N OFDM symbols, where N and T are positive integers; or ,

The station extends the length of the CCA and the eCCA by N said unit time, where N is a positive integer; or

The station stops transmitting for a period of time.

Specifically, in the case that the foregoing N ₁ CCA is successful, the parameters of the site modification FBE mode include:

The site increases the duration of the frame period; or,

The site increases the duration of the CCA; or,

The site increases the period of the CCA; or,

The site lowers the CCA threshold, or,

The site increases the length of the listening zone.

Specifically, when the site N ₁ CCA is successful, the performing the eCCA adjustment parameter by the site includes: the site enters a random backoff phase, and generates a random number Num as a random backoff number, and the value range of the random number is also For example, the range of Num is (0, num1) for the first time, the value of Num is close to the normal distribution, and the range of the random number Num after the total number of accesses in the statistical time reaches the second predefined number of times M Adjusted to (num1, num2), and num2 < 32, num2 can be 2 * num1, and so on, and, for a period of time, if the number of transmissions is less than a predefined threshold, the window length needs to be reduced. Changing the larger window length makes the access with more access opportunities slow down, and the access with fewer access opportunities is faster. There are two specific ways to randomly roll back:

Manner 1: The original frame length is maintained, and the data transmission time and idle idle time in the original frame structure are used for CCA and eCCA, wherein the length of the eCCA is the same as the length of the CCA or the duration of the 1/Z OFDM symbol. , Z is a positive integer, specifically 2, 4, 6, or 8.

Second way: CCA's position unchanged, and the discontinuity between the CCA, the site does not modify the frame structure, in order to send the site to perform N ₃ times after the success of CCA data in accordance with the original frame period, if the number of successful CCA reach N ₃ Can not occupy the channel, N _{3 is} greater than N ₁ ,

Alternatively, the site uses a random rollback each time the site performs CCA.

In this mode, the location where the site starts to perform CCA or eCCA is fixed every time, but the end position is not fixed. The length of each CCA, that is, the random backoff value is adjusted according to the last preemption result. For example, according to the transmission frame structure, if the previous CCA preemption succeeds, the length of the next CCA, the random backoff value increases, and if the CCA is not successful, the length of the CCA is shortened. The number of times or the length of the intermediate CCA at the timing of the CCA and the timing of the data transmission, that is, the value of the random backoff is randomly selected for the first time, and then adjusted according to the last preemption.

Optionally, for mode 1, the adjusting, by the site according to the preset rule, the parameter further includes:

When the site performs N ₂ CCA failures continuously or cumulatively according to the FBE mode within a preset time, and N ₂ is a preset value determined by the station according to the occupied duration, the site adjusts the parameters according to any one of the following manners:

Modifying the parameters of the FBE mode by the site; or

The site modifying the random backoff value; or,

The station shortens the window length of the random backoff by P unit time, and the unit time includes: a duration of one CCA, a duration of one eCCA, or a duration of N OFDM symbols, where N and P are positive integers; or

The station shortens the length of the CCA and the eCCA by M said unit time, and M is a positive integer.

Optionally, in the case that the foregoing N ₂ times CCA fails, the parameters of the site modifying the FBE mode include:

The station shortens the duration of the frame period; or,

The site shortens the duration of the CCA; or,

The site shortens the period of the CCA; or,

The site increases the CCA threshold, or,

The site shortens the length of the listening zone.

For mode 2, the information about the interaction negotiation includes:

The load information or the occupation time of the site, the parameter configuration information of the site in the FBE mode, or the parameter information of the site resource competition.

Optionally, the method further includes:

When the station needs to use an unlicensed carrier to transmit data, the station detects whether the unlicensed carrier is in an idle state, including:

The station performs CCA once in each of the frame periods, and the starting position of the CCA is selected by the station in a preset time window; or

The station performs an eCCA once in each of the frame periods, wherein the eCCA includes a continuous random X times CCA, X is a positive integer, and the start position of the eCCA and the value of X are selected by the station.

The preset time window is a time slot or a subframe.

Optionally, the method further includes:

When the location of the data transmission is fixed, the station sends the data before the CCA is successfully executed. Sending an initial signal, the initial signal includes at least one of the following information:

Information for notifying other stations that belong to the same operator as the site to multiplex unlicensed carriers, information for notifying the UE to which the station belongs to multiplex unlicensed carriers, and for notifying other sites that the site is unauthorized The information on the duration of the carrier.

Optionally, the adjusted parameter is used to control a site access probability and/or occupation time of the spectrum.

Optionally, when the site is a user equipment UE and the UE needs to transmit uplink data, the determining, by the station, the parameters of the frame in the unlicensed carrier includes:

Determining, by the UE, the parameter, and reporting the parameter to a base station to which the UE belongs;

Optionally, the reporting the parameter to the base station to which the UE belongs includes:

The UE sends uplink control information UCI to the base station by using an authorized carrier or a contending unlicensed carrier, where the UCI includes the parameter.

Optionally, when the site performs the CCA for the uplink data transmission by the user equipment UE, the determining, by the station, the parameters of the frame in the unlicensed carrier includes:

The base station to which the UE belongs configures the parameter and sends the parameter to the UE.

Optionally, the sending, by the base station to which the UE belongs, the parameter to the UE includes:

The base station determines, according to the buffer status report BSR and the authorized carrier resource, the UE that is scheduled to be in the same subframe, and sends the parameter to the UE.

In order to enable those skilled in the art to more clearly understand the technical solutions provided by the present invention, the technical solutions provided by the present invention are described in detail below through specific embodiments:

Embodiment 1

The method for introducing the data transmission provided by the embodiment of the present invention in the LBT based on the FBE mode is described in detail in this embodiment.

Here, we will first briefly introduce the way to control FBE and the way of LBE.

As shown in Figure 3, for FBE, it has a fixed transmission frame structure, channel occupancy time and idleness. The period constitutes a fixed frame period, and the device performs CCA detection during the idle period. When the channel is detected to be idle, the data transmission can be performed immediately. If the idle channel is not detected during the idle period, the device performs the idle period of the next fixed frame period. CCA testing. For FBE in Europe, the channel occupancy time is 1ms to 10ms, and the idle period is at least 5% of the channel occupation time. The CCA test lasts for at least 20 μs, and the CCA test can be based on energy detection or based on signal detection.

As shown in Figure 4, for LBE, load-based contention. That is, when there is a data transmission requirement, the device starts to perform CCA detection. If the channel is found to be idle after the CCA detection, the data transmission can be performed immediately, and the maximum time that the data transmission can be occupied is (13/32)× q ms, where q={4,5,6...31,32} is configurable; if the channel is found to be busy after performing CCA detection, enter the extended CCA (eCCA) detection period, that is, X times CCA detects that the value of X is stored in a counter, where the X value is randomly selected from 1 to q. Each time the CCA is detected (the same time for each CCA detection), if the channel is found to be idle, the counter starts to decrement if the channel is not If it is idle, the counter will not be decremented. When the counter is decremented to 0, data transmission can be started. The data transmission time is determined according to requirements, but the maximum cannot exceed (13/32) × q ms.

In the embodiment of the present invention, the process of specifically listening to the LBT after data transmission is summarized as follows:

At the beginning of the site, the target unlicensed carrier is detected according to the CCA timing and detection length specified by the FBE. For example, if the length of the CCA is 20 μs, and the channel is found to be idle, the station transmits data according to a fixed frame period, and when the subsequent satisfaction is satisfied. When the condition is met, the random back-off phase is entered (that is, N successful CCAs are performed). If the condition is not satisfied, the channel detection and data transmission are continued according to the fixed frame period of the FBE and the position of the CCA. The conditions stated include:

Condition 1: The total occupancy time of the site exceeds a certain threshold T1 within a given statistical time.

Condition 2: The number of times the site performs CCA success continuously or cumulatively exceeds the predefined threshold N ₁ .

The range of the random number Num is selected according to the occupation duration and/or the number of occupations, and the value of Num is close to the normal distribution.

For example, the range of Num is (0, num1) for the first time, and after the total number of accesses in the statistical time reaches the second predefined number of times M, the range of the random number Num is adjusted to (num1, num2), and num2<32 , num2 can be 2*num1, and so on. Moreover, for a period of time, if the number of transmissions is less than a predefined threshold, the window length needs to be reduced. Change the larger window length to make The number of incoming opportunities is gradually slower, and the access with fewer access opportunities is faster.

There are two ways to specifically roll back.

Manner 1: Keep the original frame length, use the data transmission time and idle time in the original frame structure for CCA, each CCA is continuous, the total CCA is eCCA, and the random backoff is equal to the original frame. An integer multiple of the period or subframe.

As shown in Figure 5, the site successfully performs two consecutive CCAs, including transmitting data once after the first CCA is successful. After the second CCA is successful, it needs to enter immediately because it meets the condition that the number of consecutive successful times reaches the threshold of 2. In the random backoff phase, a random number N=8 is generated, and data transmission can no longer be performed. In this way, other sites can transmit data on an unauthorized basis after a successful CCA during this period.

The length of the specific initial CCA may be 20 μs, or 18 μs or 1/2 OFDM symbol length. The length of each CCA in the extended CCA or eCCA may be the same as the length of the first CCA, or smaller than the length of the initial CCA, such as 1/4. , or the duration of 1/8 OFDM symbols.

Manner 2: The location of the CCA is unchanged, and the two CCAs are discontinuous. That is, the frame structure of the site FBE is not modified. The station can perform channel transmission data after performing N times of CCA success according to the original frame period.

As shown in Figure 6, the frame structure and period of the station are unchanged, but after consecutively performing CCA twice and performing two data transmissions, it is necessary to generate a random number N=3, that is, only after three consecutive CCA successes can be transmitted. If it does not reach 3 consecutive times, even if CCA is successful, it cannot be transmitted.

If the CCA does not succeed in the predefined statistical time, or the number of CCA successes does not reach the predefined threshold, it does not need to enter the random backoff phase, and still maintain the original CCA period and frame structure for channel idle detection and data transmission. .

In particular, for the uplink, if the UE performs CCA, the specific random backoff mode and parameters are controlled by the base station to implement multi-user FDM (Frequency Division Multiplexing).

Optionally, after determining, by the base station, that the UEs in the same subframe are scheduled, the UEs are configured with the same CCA location or a random backoff value. The specific random backoff value is controlled by a Radio Resource Control (RRC) message or Downlink Control Information (DCI). Notify the UE.

It can be seen that the difference between the method and the LBE random backoff is that the starting position of each CCA is fixed, and the station enters the random backoff when detecting that the channel idle times reach a certain threshold, and randomly falls back. The way will be different.

It can be seen from the embodiment that the time when the non-authorized carrier is occupied by the site is controlled by controlling the random backoff value, so that the time for each site to occupy the unlicensed carrier as a whole is similar, and the effect of fair occupation of unauthorized resources is achieved. Solve the problem of synchronous interference.

Embodiment 2

This embodiment describes the manner in which the site performs a random backoff each time the CCA is executed according to the FBE frame period.

In this mode, the location where the site starts to perform CCA or eCCA is fixed every time, but the end position is not fixed. The length of each CCA/eCCA is adjusted based on the last preemption result. For example, according to the frame structure, if the previous CCA/eCCA preemption succeeds, the length of the next CCA/eCCA increases. If the CCA/eCCA is not successful, the length of the CCA/eCCA is shortened.

The number of times or the length of the intermediate CCA at the timing of the CCA and the timing of the data transmission, that is, the value of the random backoff is randomly selected for the first time, and then adjusted according to the last preemption. The time length of the first CCA or eCCA of the site is L1, but no access is successful, that is, other sites have priority access than the site, and the next time the CCA is selected, a smaller value is selected, so that the site is connected. The opportunity to enter can be greatly improved. Conversely, if the site's previous access was successful, the next time a larger CCA time length is selected.

And, if the station preemption is successful, the station needs to send an initial signal in the middle of the end position of the CCA/eCCA and the timing position at which the data starts to be transmitted. The initial signal is used for carrier occupation on the one hand, and can perform some measurements on the other hand, such as radio resource management (RRM) measurement or channel quality measurement, and automatic gain control (AGC) adjustment. The initial signal is a preamble sequence, a reference signal or part of the user data.

For example, as shown in FIG. 7, the station 1 in (a) is at the timing according to the CCA and the random backoff value. After Num=1CCA is successful, the initial signal is sent until the data start position. After the multi-site or UE multiplex transmission completes the data transmission, the next time Num is expanded to 5, the access is failed. In contrast, in (b), for station 2, the value of the first Num is 4 without success, and the value of the second Num is changed from 4 to 2, and the competition is successful and the data transmission is completed.

It should be noted that, in the carrier aggregation mode, the start position of the data transmission is determined according to the timing relationship of the aggregated licensed carrier, that is, the unlicensed data transmission subframe boundary is aligned with the primary carrier, that is, the authorized carrier subframe boundary. In addition, the initial signal may also carry an operator identifier, and other stations that notify the same operator may also perform data transmission on the unlicensed carrier.

The remaining time slots of the subframe in which the LBT slot is located are used to transmit part of the data of the user, or to transmit a Primary Synchronization Signal (PSS) or a Secondary Synchronization Signal (SSS), and a cell-specific pilot ( Cell-specific Reference Signal (CRS), Channel Status Information-Reference Signal (CSI-RS) or SRS or preamble sequence.

This method can solve the interference problem when two or more stations start CCA at the same time and simultaneously transmit data successfully, so that each station access time is randomized, and the access times or durations of each station are controlled.

Embodiment 3

The method for the LBT of the FBE provided in the embodiment of the present invention is that the blank time zone included in the frame period, that is, the idle idle period, the time of the eCCA, and the length of the data transmission time and the frame period parameter may all be fixed values. Or semi-static or dynamic configuration adjustments.

This embodiment first describes a case where the frame period adjustment is adjusted according to the unlicensed carrier access situation.

The system pre-defines many frame periods, and each station adjusts the frame period semi-statically or dynamically according to the system's predefined principles.

There are several candidates for the frame period. For example, the value is 2ms, 3ms, 4ms, 10ms, that is, K integer multiples of the subframe. The structure of each frame period is fixed, that is, the CCA position, duration, idle period idle, and channel occupancy. The time (Channel Occupancy Time, COT) is fixed. Base station based on accumulated CCA The result and the duration of the adjustment frame period are adjusted and the uplink and/or downlink (UP LINK and/or DOWN LINK, UL and/or DL) frame periods are given by RRC messages or more flexible DCI dynamic indications.

The principles of specific frame period determination and adaptive adjustment are as follows:

If the station continuously performs N1 (N1 is a predefined threshold) and the CCA is not successful according to the fixed frame period (FP), the next time the smaller frame period FP2 is selected, if the FP2 is continuously executed N2 times, the system still fails. , select a smaller period FP3 until the access is successful. If the access is successful, and the number of successes or the accumulated duration exceeds the predefined threshold M1, the frame period is further increased.

For example, if the station does not succeed in CCA for three consecutive 4ms frame periods, it is changed to a 2ms frame period. If the site succeeds 5ms twice in succession, it needs to be changed to 10ms.

The station changes the frame period by accessing the statistics and principles to achieve fair access to the unlicensed carrier.

Embodiment 4

This embodiment describes the case where the CCA adjusts according to the unlicensed carrier access situation.

The CCA flexibility of the site can be changed in the following ways.

Manner 1: Predetermine different CCA lengths, for example, the length of the CCA is 1/2 OFDM symbol duration (about 33.3 μs), the duration of the 1/4 OFDM symbol (about 16.67 μs), or the duration of the 1/8 OFDM symbol (about 8.92 μs). ), the long CCA access probability is small, the short access probability is large, and the CCA length in each station frame period is adjusted according to the preemption and occupation time, and the adjustment principle is similar to the above cycle adjustment.

Manner 2: Each time the CCA length is fixed, the cycle and offset of multiple CCAs are defined, the long-period access is slow, and the short-cycle access is fast. It is also adjusted according to the statistical preemption situation: if the occupation time exceeds the threshold within a certain period of time, it is adjusted to a longer period. If the occupation time is less than the threshold, it is adjusted to a shorter period.

The base station notifies the UE of the specific configuration through a System Information Block (SIB) or an RRC message or a DCI. For example, the system can define the CCA period and offset as shown in the following table:

Configuration index	Bit	Period (subframe)	Offset (subframe)
0	0000	1	{0}
1	0001	2	{0}
2	0010	2	{1}
3	0011	4	{0}
4	0100	4	{1}
5	0101	4	{2}
6	0110	4	{3}
7	0111	4	{0,1}
8	1000	4	{2,3}
9	1001	10	{0}
10	1010	10	{1}
11	1011	10	{2}
12	1100	10	{3}
13	1101	10	{0,1,2,3,4,6,8}
14	1110	10	{0,1,2,3,4,5,6,8}
15	1111	Reserved reserved	Reserved

Mode 3: The system defines multiple CCA thresholds, and the site adjusts the CCA threshold according to the detection result and the occupation time. For example, if the station fails to use the threshold-62dBm cumulative CCA four times without success, the threshold is adjusted to -42. If the cumulative three times is not successful, then the threshold is adjusted to -22, so if the cumulative If you succeed three times, you need to increase the threshold, for example, back to -42 or -62.

By changing one or more of the above CCA parameters, the site can solve the problem of unauthorised unfairness and the constant access of the site.

Embodiment 5

This embodiment describes a method for adjusting an idle idle period according to an unlicensed carrier access situation.

Similar to CCA, the FBE is configured with different lengths of idle time, and each site can be flexibly adjusted. For example, if the fixed frame period is 4 ms, the idle duration configuration can be from 3 OFDM symbols to 1 ms or longer.

Specific adjustment principle: In the statistical time, the site occupies one time or continuously or cumulatively takes up to k times and then expands the idle duration. Or the carrier changes the length of the idle in turn.

For example, as shown in FIG. 8, assuming that the frame period is fixed to 4 ms, the station adjusts the idle period idle as shown in (a), and the station 2 expands the idle duration after occupying one time, and expands from 1 ms to 2 ms, so that the station 1 There is a chance to access. Or the station alternately expands the idle period, as in (b), which also ensures that both sites can access.

Embodiment 6

In this embodiment, the case where the occupation duration in the frame period is adjusted according to the unlicensed carrier access situation will be described.

The flexible configuration takes up the length of time, that is, the UL or DL transmission time is not fixed. For example, the data transmission time takes the value of 1 ms, 2 ms, 4 ms, and 10 ms, and the base station gives the configuration index UL and/or DL transmission duration by using an RRC message or a more flexible DCI dynamic indication.

As shown in FIG. 9, it is assumed that the base station configures the downlink DL transmission time to be 5 ms and the uplink UL transmission time to be 3 ms in a period of time, and the time division duplex (TDD) system site performs LBT and data transmission. The frame structure diagram can be as shown in FIG.

At the same time, the uplink scheduling and transmission process can be as follows:

The base station determines the UEs scheduled in the same subframe, and determines the uplink duration (or consecutive subframes) of each UE unlicensed carrier according to the Buffer Status Report (BSR) and the duration of the occupied UE. The number of UL durations and the downlink grant UL grants, and these UEs are configured with the same CCA location (if the LBE, including the same random backoff value).

And then the above information is indicated to each UE by the grant carrier DCI multi-subframe scheduling;

The UE then performs CCA, and if successful, performs multi-subframe continuous transmission according to the base station configuration.

As shown in FIG. 10, the base station configures UE1 and UE2 with the duration of the UL duration as 5 consecutive subframes and gives the CCA subframe position or the starting subframe position of the data transmission in the DCI, then the two UEs follow the indication. Perform CCA and perform uplink data transmission if successful.

Example 7

This embodiment describes a method for coordinating different parameters of the FBE at two sites.

The parameters herein include one or more of a transmission frame period, a CCA period, an OFDM symbol position starting from the CCA, a CCA time domain length, a CCA threshold, a listening area duration, an occupation duration, a random backoff value, and a silence time.

For example, two sites negotiate different FBE parameters through defined air interfaces, such as public resources, or preset interfaces. For example, the frame period of the site 1 configuration is 3 ms, the frame period of the site 2 is 2 ms, or after a period of time, the two stations exchange the frame period size.

In addition to adjusting or negotiating relevant parameters according to the preemption situation, the site can coordinate the configuration of the relevant parameters of different sites through the Operation Administration and Maintenance (OAM) background, so that each site performs LBT according to the parameter configuration. And data transmission, can also avoid collision problems caused by multiple sites competing for resources at the same time and carrying out data transmission on unauthorized. Moreover, it can also avoid the unfair situation that a site can always send data and the other sites around it do not enter.

Example eight

This embodiment describes a method of defining an idle period.

For the occupied station, or defining the subframe, the subframe may be continuous or discrete, for example, the subframe number satisfies mod(n, T)=k, n is the system frame number, T is a predefined period, and k is a partial When shifting, the values of T or K at different sites are different. The base station or UE cannot transmit data on whether or not the unlicensed carrier is occupied.

Optionally, for example, each subframe 6 cannot be transmitted, or the sixth subframe of the system multiple frame number of 2 is not transmitted for a period of time. The time that cannot be transmitted is at least 34μs, such as 40μs. Or a symbol, or a time slot. At least the Distributed Inter-frame Spacing (DIFS) length is accessible to devices or other sites in the Wi-Fi network wifi system.

Alternatively, the station forcibly fails to perform CCA and data transmission after continuously transmitting n subframes.

As shown in FIG. 11, after the station 1 continuously transmits 4 frame periods, the CCA cannot be transmitted in the next frame period, so that the station 2 performs the CCA success and continuously transmits 4 frame periods. Thereafter, As with Site 1, CCA and data transmission are forcibly disabled when the next frame period arrives, so that other stations can continue to transmit.

Example nine

This embodiment describes a case where a non-authorized use is adopted by a coordination method between sites.

Sites can be negotiated by different defined air interfaces or defined interfaces. Different sites of different operators can be used by Time Division Multiplexing (TDM). The same unlicensed spectrum.

For example, two adjacent stations can notify their own load information to the other party. If one party has a low load, the unlicensed carrier can be given to the site with high load in the most recent period of time. Subsequent if the site load becomes high, it can be notified to the previously transferred site, and the site can use the unlicensed carrier for transmission in the most recent period of time. If the two sites load the same, you can send the data in an alternate way. For example, each site sends 1ms or 2ms in turn.

In addition to the TDM method, the two stations can also transmit data by using Frequency Division Multiplexing (FDM), that is, selecting different unlicensed carriers.

Example ten

This embodiment describes a case where the device that performs CCA on the site is a UE.

For the UE to perform CCA for uplink data transmission, the UE has two ways to determine the parameters, such as a frame period, a CCA period and a symbol position, a CCA time domain length, a CCA threshold, an idle length, an occupied duration, a random backoff value, and a silent time. Wait.

Manner 1: The configuration is performed by the base station to which the UE belongs. The process is as shown in (a) of FIG.

First, the base station determines the parameters of the LBT, and notifies the parameters described by the UE through high layer signaling or physical DCI signaling. The UE performs LBT and data transmission according to the received parameters.

Manner 2: The UE adjusts the parameters of the LBT according to the stated principle, and reports the result to the base station. The process is as shown in (b) of FIG.

The UCI (Uplink Control Information) reported by the authorized carrier or the unlicensed carrier that is contending is reported.

Then, the UE performs resource competition according to the determined parameters, and sends uplink data after success.

Embodiment 11

In the embodiment, the implementation process of the method provided by the embodiment of the present invention is described in the case where the device performing CCA is a base station.

For downlink data transmission, the process is as shown in FIG.

First, the base station determines resource competition and data transmission parameters according to the access time and adjustment principle in the statistical time. or

The base station negotiates with surrounding base stations or other devices to determine parameters corresponding to the frame structure.

Then, the base station notifies the related parameters or the adjustment parameters of the UE to the UE through the SIB or the RRC message or the DCI, and performs resource competition according to the determined parameters, and sends the downlink data after the success.

For the uplink data transmission, the base station may also configure the parameters according to the reporting result of the UE, and notify the UE through the physical layer signaling, and the UE performs resource competition and uplink data transmission according to the parameters determined by the base station.

It should be noted that the implementation of the scenario at the two sites given in the above embodiments also applies to more than two sites. Moreover, the above-mentioned several solutions are mainly for solving the problems related to different operator sites, and are also applicable to the sites of the same carrier. In addition, the sites of the same carrier can select different carriers through the X2 interface negotiation manner. Or use the same unlicensed carrier at the time. Moreover, although the listening area in the frame structure shown in the figure is generally located in front of the subframe, the listening area may actually be located at the end of the frame structure, that is, the next data transmission. front.

The data transmission method provided by the embodiment of the invention solves the problem of resource competition, data scheduling and transmission when the LTE performs uplink data transmission on the unlicensed carrier, realizes the randomization of the site access, and avoids the problem that the station simultaneously finds the idle collision. And unfair access issues.

The embodiment of the invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the above method.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be performed by a program to instruct related hardware, such as a processor, which may be stored in a computer readable storage medium, such as a read only memory, disk or optical disk. Wait. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware, for example, by implementing an integrated circuit to implement its corresponding function, or may be implemented in the form of a software function module, for example, executing a program stored in the memory by a processor. / instruction to achieve its corresponding function. The invention is not limited to any specific form of combination of hardware and software.

While the embodiments of the present invention have been described above, the described embodiments are merely for the purpose of understanding the invention and are not intended to limit the invention. Any modification and variation in the form and details of the embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention. The scope defined by the appended claims shall prevail.

Industrial applicability

The above technical solution can avoid the transmission collision problem and the access unfairness problem between different sites when the LTE system operates in the unlicensed carrier frequency band, and improve the spectrum efficiency.

Claims (20)

1. A method of data transmission, comprising:

   The station determines parameters of frames in the unlicensed carrier;

   The structure of the frame includes: a listening area for detecting whether a subframe in the frame is in an idle state, and a data transmission area for transmitting data;

   The parameters of the frame include at least one of: a frame period, a period of a clear channel evaluation CCA, an orthogonal frequency division multiplexing OFDM symbol position starting from a CCA, a duration of a CCA, a CCA threshold, a duration of the listening area, and the data. The duration of the transmission area, the extended idle channel evaluation, the random backoff value of the eCCA, the window length of the random backoff, the silence time, and the time at which the data transmission is stopped.
2. The method of claim 1 further comprising:

   The station adjusts the parameters according to a preset rule.
3. The method of claim 2, wherein the adjusting the parameters by the station according to a preset rule comprises:

   When the other station based on the frame device FBE continuous or accumulated execution times N ₁ CCA successful, the site N ₁ is determined according to the preset value of the long time occupied, the adjustment station for a preset time according to any one of the following ways The parameters:

   Modifying the parameters of the FBE mode by the site; or

   The site performs eCCA; or,

   The station increases the window length of the random backoff by T unit time, where the unit time includes: a duration of one CCA, a duration of one eCCA, or a duration of N OFDM symbols, where N and T are positive integers; or ,

   The station extends the length of the CCA and the eCCA by N said unit time, where N is a positive integer; or

   The station stops transmitting for a period of time.
4. The method of claim 3, wherein the parameters of the site modification FBE mode include:

   The site increases the duration of the frame period; or,

   The site increases the duration of the CCA; or,

   The site increases the period of the CCA; or,

   The site lowers the CCA threshold, or,

   The site increases the length of the listening zone.
5. The method of claim 2, wherein the adjusting the parameters by the station according to a preset rule comprises:

   When the site performs N ₂ CCA failures continuously or cumulatively according to the frame device FBE mode within a preset time, and N ₂ is a preset value determined by the station according to the occupied duration, the site adjusts the method according to any one of the following manners. Description parameters:

   Modifying the parameters of the FBE mode by the site; or

   The site modifying the random backoff value; or,

   The station shortens the window length of the random backoff by P unit time, and the unit time includes: a duration of one CCA, a duration of one eCCA, or a duration of N OFDM symbols, where N and P are positive integers; or

   The station shortens the length of the CCA and the eCCA by M said unit time, and M is a positive integer.
6. The method of claim 5, wherein the parameters of the site modification FBE mode include:

   The station shortens the duration of the frame period; or,

   The site shortens the duration of the CCA; or,

   The site shortens the period of the CCA; or,

   The site increases the CCA threshold, or,

   The site shortens the length of the listening zone.
7. The method of claim 1 further comprising:

   The site negotiates with other sites through an air interface or a preset interface, and adjusts the parameters according to the information of the interaction negotiation.
8. The method of claim 7, wherein the information of the interaction negotiation comprises:

   The load information or the occupation time of the site, the parameter configuration information of the site in the frame device FBE mode, or the parameter information of the site resource competition.
9. The method of claim 1 further comprising:

   When the station needs to use an unlicensed carrier to transmit data, the station detects whether the unlicensed carrier is in an idle state, including:

   The station performs CCA once in each of the frame periods, and the starting position of the CCA is selected by the station in a preset time window; or

   The station performs an eCCA once in each of the frame periods, wherein the eCCA includes a continuous random X times CCA, X is a positive integer, and the start position of the eCCA and the value of X are selected by the station.
10. The method according to claim 9, wherein the preset time window is one time slot or one subframe; the duration of each CCA in the eCCA is the same as the time length of the first CCA, or the eCCA is CCA each time The duration is 1/Z OFDM symbols, and Z is a positive integer.
11. The method of claim 9 further comprising:

    When the location of the data transmission is fixed, the station sends an initial signal before transmitting the data after performing the CCA success, and the initial signal includes at least one of the following information:

    Information for notifying other stations that belong to the same operator as the site to multiplex unlicensed carriers, information for notifying the UE to which the station belongs to multiplex unlicensed carriers, and for notifying other sites that the site is unauthorized The information on the duration of the carrier.
12. The method of claim 1, wherein the data transmission area is for transmitting at least one of: user data, control information, reference signals or sequences for measuring or synchronizing or occupying functions, and system messages related information.
13. The method according to claim 1, wherein the number of uplink subframes or downlink subframes included in the data transmission area is dynamically adjusted.
14. The method of claim 1 wherein the silence time of the different stations or the time at which the data transmission is stopped is different.
15. The method of claim 1 further comprising:

    The station adjusts the parameters based on the results of the statistical CCA.
16. The method of claim 2 or 7 or 15, wherein the adjusted parameters are used to control a station's access probability and/or occupancy time for the spectrum.
17. The method according to claim 1, wherein when the station is a user equipment UE and the UE needs to transmit uplink data, the determining, by the station, parameters of a frame in the unlicensed carrier includes:

    The UE determines the parameter, and reports the parameter to the base station to which the UE belongs.
18. The method according to claim 17, wherein the reporting the parameter to the base station to which the UE belongs includes:

    The UE sends uplink control information UCI to the base station by using an authorized carrier or a contending unlicensed carrier, where the UCI includes the parameter.
19. The method according to claim 1, wherein when the station performs CCA for uplink data transmission for the user equipment UE, the parameters of the frame determined by the station in the unlicensed carrier include:

    The base station to which the UE belongs configures the parameter and sends the parameter to the UE.
20. The method according to claim 19, wherein the base station to which the UE belongs is configured to send the parameter to the UE, and the method includes:

    The base station determines, according to the buffer status report BSR and the authorized carrier resource, the UE that is scheduled to be in the same subframe, and sends the parameter to the UE.

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