WO2017193365A1

WO2017193365A1 - Uplink transmission methods, resource assignment methods, user equipment, and base stations using unlicensed spectrum

Info

Publication number: WO2017193365A1
Application number: PCT/CN2016/082005
Authority: WO
Inventors: Xiang Chen; Chunhua Sun; Eddy Chiu
Original assignee: Huizhou Tcl Mobile Communication Co., Ltd
Priority date: 2016-05-13
Filing date: 2016-05-13
Publication date: 2017-11-16
Also published as: CN109565692A; CN109565692B

Abstract

An uplink transmission method using unlicensed spectrum is disclosed, comprising: performing a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment in an assigned frequency resource segment group, and thus determining whether the at least one sub-channel is clear, wherein the frequency resource segment group may be generated by segmenting and grouping the unlicensed spectrum; and when the at least one sub-channel corresponding to the at least one frequency resource segment is clear, using at least one clear sub-channel for uplink transmission. Resource assignment methods, user equipment, and base stations using unlicensed spectrum are also disclosed. The present disclosure can reduce the blocking probability among intra-cell and inter-cell user equipment (UE) during Licensed- Assisted Access (LAA) uplink transmission, and thus can improve the channel access probability.

Description

UPLINK TRANSMISSION METHODS, RESOURCE ASSIGNMENT METHODS, USER EQUIPMENT, AND BASE STATIONS USING UNLICENSED SPECTRUM

FIELD OF THE DISCLOSURE

The present disclosure relates to the field of communications, and more particularly, to uplink transmission methods, resource assignment methods, user equipment, and base stations, using unlicensed spectrum.

BACKGROUND OF THE DISCLOURE

As wireless communications continue to develop and the demand for mobile broadband is rapidly increasing, the scarcity of spectrum resources, especially licensed spectrum resources, has posed an urgent challenge to mobile communications. To meet the increasingly growing demand for data rate, traffic, and bandwidth, and thus to mitigate the current spectrum scarcity crisis, 3GPP has launched a study item on Licensed-Assisted Access (LAA) to unlicensed spectrum.

LAA is an auxiliary access technology which offloads the cellular traffic in the licensed band to the unlicensed spectrum. By means of the carrier aggregation framework, a licensed carrier may be used to carry critical information to maintain the Quality of Service (QoS) , while another carrier on the unlicensed band may be opportunistically employed to boost the data rate.

The LAA technology, however, may cause interference to other wireless technologies currently working on the same band, such as Wi-Fi. Likewise, the LAA networks deployed by different operators may also interfere with each other. Therefore, one of the main design targets of the LAA is to establish an effective and fair resource competition mechanism for different transmission nodes deployed on a common unlicensed band, including Wi-Fi networks, and LAA networks deployed by different operators.

The listen-before-talk (LBT) procedure is defined as a mechanism by which a piece of equipment applies a clear channel assessment (CCA) before using the channel. The LBT procedure is considered to be a vital feature for fair and friendly operation in the unlicensed spectrum. In addition, European and Japanese regulations mandate the usage of LBT in the unlicensed spectrum, which should be taken into account when building a single global solution framework with LAA.

Typically, the frequency-division multiplexing (FDM) technology may be frequently employed in mobile communication systems for uplink transmission, namely, different UEs within the same cell can be assigned with one portion of the entire bandwidth respectively, and thus can upload data simultaneously. When it is applied to LAA, however, this technology can lead the uplink transmission process of one UE to block the LBT process of another neighboring UE, even the two neighboring UEs have been assigned with different portions of the bandwidth.

SUMMARY OF THE DISCLOSURE

In view of the above, a principal technical problem to be addressed by disclosure is to provide uplink transmission methods, resource assignment methods, user equipment, and base stations, using unlicensed spectrum. The present disclosure can solve the problem of high blocking probability among the LBT procedures of intra-cell and inter-cell UEs during LAA uplink transmission.

To address the above problem, one technical solution adopted by the disclosure is to provide an uplink transmission method using unlicensed spectrum, comprising: performing a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment in an assigned frequency resource segment group, and thus determining whether the at least one sub-channel is clear, wherein the frequency resource segment group may be derived by segmenting and grouping the unlicensed spectrum, each sub-channel corresponding to a unique frequency segment； and when the at least one sub-channel is clear, using at least one clear sub-channel for uplink transmission.

The block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment may comprise: performing the CCA on the at least one sub-channel within a preset detection period before an allocated transmission period.

The method may further comprise, before the block of using the at least one clear sub-channel for uplink transmission: when there is a time interval between after determination the at least one sub-channel is evaluated as clear and a start of the allocated transmission period, using the at least one clear sub-channel to transmit reservation signals during the time interval to indicate that the at least one clear sub-channel is occupied or will be occupied.

The block of performing the CCA on the at least one sub-channel within the preset detection period before the allocated transmission period may comprise: selecting a random number from a contention window； repeatedly performing the CCA on the at least one sub-channel within the preset detection period before the allocated transmission period； if a duration of the at least one sub-channel being detected as idle is not shorter than a duration represented by the random number, determining that the at least one sub-channel is clear.

A size of the contention window may be determined according to at least one of importance of the uploaded data, an upload waiting time, a traffic load condition, and a historical LBT failure rate.

The block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment may further comprise: if during the preset detection period before a previous transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear is larger than a preset value, re-performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the preset detection period before a subsequent transmission period.

The CCA of the subsequent transmission period may use the same or more aggressive detection parameters than the CCA of the previous transmission period.

The detection parameters may comprise a size of the contention window and/or the preset detection period.

The detection parameters may be acquired from a control signal transmitted from the base station, or autonomously determined.

The block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment may further comprise: if during the preset detection period before a transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear is larger than a preset value, continuing performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the transmission period.

The method may further comprise: acquiring from a control signal transmitted from a base station the information of the assigned frequency resource segments and assigned transmission periods.

The block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment may comprise: performing energy detection on the at least one sub-channel and thus acquiring the signal energy in the at least one sub-channel； and if the signal energy is not higher than a preset threshold value, determining the at least one sub-channel to be idle.

Another technical solution adopted by the disclosure is to provide a resource assignment method using unlicensed spectrum, comprising: receiving a frequency resource segment indicator (FRSI) from at least one neighboring cell, wherein the FRSI may indicate the assignment information of the frequency resources of the unlicensed spectrum in the at least one neighboring cell； and assigning the frequency resources of the unlicensed spectrum within the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell.

The method may further comprise: informing periodically or aperiodically the FRSI of the present cell to the at least one neighboring cell.

The assignment information may comprise the segmenting and/or grouping information of the frequency resources of the unlicensed spectrum. The block of assigning the frequency resources of the unlicensed spectrum within the present cell based on relevant information provided by the FRSI from the at least one neighboring cell may comprise: segmenting and/or grouping the frequency resources of the unlicensed spectrum within the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell and thus deriving frequency resource segments or frequency resource segment groups for the present cell.

The block of assigning the frequency resources of the unlicensed spectrum among the present cell based on relevant information provided by the FRSI from the at least one neighboring cell may further comprise: assigning the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) , enabling the frequency resource segments or frequency resource segment groups assigned to the at least one UE within the present cell to not overlap with those assigned to at least one UE within each of the at least one neighboring cell.

The method may further comprise: acquiring an LBT failure rate indicator (LFRI) used to indicate a failure rate of the LBT procedures corresponding to the frequency resource segments or frequency resource segment groups； and at least re-assigning the frequency resources among the present cell based on the relevant information provided by the LFRI, or adjusting the transmission power or detection parameters of UEs within the present cell, based on the relevant information provided by the LFRI.

The method may further comprise: informing periodically or aperiodically the LFRI of the present cell to the at least one neighboring cell.

The block of re-assigning the frequency resources among the present cell based on the relevant information provided by the LFRI may comprise: re-segmenting and/or re-grouping the frequency resources of the present cell based on the relevant information provided by the LFRI； and/or re-assigning the frequency resource segments or frequency resource segment groups among the UEs within the present cell, based on the relevant information provided by the LFRI.

Yet another technical solution adopted by the disclosure is to provide a user equipment (UE) , comprising: a detection module configured to perform a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment in an assigned frequency resource segment group and thus determine whether the at least one sub-channel is clear, wherein the frequency resource segment group may be derived by segmenting and grouping the unlicensed spectrum, each sub-channel corresponding to a unique frequency segment； and an upload module configured to, when at least one sub-channel corresponding to the frequency resource segments is clear, use at least one clear sub-channel for uplink transmission.

The detection module may comprise a front detection unit configured to perform the CCA on the at least one sub-channel within a preset detection period before an allocated transmission period.

The front detection unit may comprise: a selection sub-unit configured to select a random number from a contention window； a detection sub-unit configured to repeatedly perform the CCA on the at least one sub-channel within the preset detection period before the assigned transmission period； and a determination sub-unit configured to, if a duration of sub-channel as idle is not shorter than a duration represented by the random number, determine that the at least one sub-channel is clear.

The detection module may further comprise a re-detection unit configured to, if during the preset detection period before a previous transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear is larger than a preset value, re-perform the CCA on the at least one sub-channel within the preset detection period before a subsequent transmission period.

The CCA of the subsequent transmission period may use the same or more aggressive detection parameters than the CCA of the previous transmission period. The detection parameters may comprise a size of the contention window and/or the preset detection period.

The detection module may further comprise a continue-detection unit configured to, if during the preset detection period before a transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel as non-idle is larger than a preset value, continue performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the transmission period.

The UE may further comprise an acquisition module configured to acquire from a control signal transmitted from a base station the information of the assigned frequency resource segments or frequency resource segment groups and the assigned transmission periods.

Still another technical solution adopted by the disclosure is to provide a base station. The base station may comprise: a receiving module configured to receive a frequency resource segment indicator (FRSI) from at least one neighboring cell used to indicate the assignment information of the frequency resources of the unlicensed spectrum in the at least one neighboring cell； and an assignment module configured to assign the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell.

The base station may further comprise a transmitting module configured to inform periodically or aperiodically the FRSI of the present cell to the at least one neighboring cell.

The assignment information may comprise the segmenting and/or grouping information of the frequency resources of the unlicensed spectrum. The assignment module may comprise a first assignment unit configured to segment and/or group the frequency resources of the unlicensed spectrum of the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell and thus derive the frequency resource segments or frequency resource segment groups for the present cell.

The assignment module may further comprise a second assignment unit configured to assign the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell, enabling that the frequency resource segments or frequency resource segment groups assigned to the at least UE within the present cell do not overlap with those assigned to at least one UE within each of the at least one neighboring cell.

The base station may further include: an acquisition module configured to acquire an LBT failure rate indicator (LFRI) used to indicate a failure rate of the LBT procedures corresponding to the frequency resource segments or frequency resource segment groups； and a regulation module configured to at least: re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI, or adjusting the transmission power or detection parameters of UEs within the present cell, based on the relevant information provided by the LFRI.

The transmitting module may also periodically or aperiodically inform the LFRI of the present cell to the at least one neighboring cell.

Still another technical solution adopted by the disclosure is to provide a user equipment (UE) comprising a processor and a communication circuit electrically connected to the processor. The processor may: perform through the communication circuit a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment in an assigned frequency resource segment group and thus determine whether the at least one sub-channel is clear, wherein the frequency resource segment group may be derived by segmenting and grouping the unlicensed spectrum； and, when the at least one sub-channel corresponding to the at least one frequency resource segment is clear, use at least one clear sub-channel for uplink transmission through the communication circuit.

The processor may perform through the communication circuit the CCA on the at least one sub-channel within a preset detection period before an allocated transmission period.

The processor may further, when there is a time interval between after determination the at least sub-channel is evaluated as clear and a start of the assigned transmission period, use the at least clear sub-channel to transmit reservation signals during the time interval to indicate that the at least one clear sub-channel is occupied or will be occupied.

The processor may: select a random number from a contention window； repeatedly perform the CCA on the at least one sub-channel within the preset detection period before the assigned transmission period； and, if a duration of the at least one sub-channel as idle is longer than a duration represented by the random number, determine the at least one sub-channel is clear.

A size of the contention window may be determined according to at least one of importance of the uploaded data, upload waiting time, a traffic load condition, and a historical LBT failure rate.

The processor may further re-perform, if during the preset detection period before a previous transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear is larger than a preset value, the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the preset detection period before a subsequent transmission period through the communication circuit.

The processor may further acquire through the communication circuit the detection parameters from a base station, or autonomously determine the detection parameters.

The processor may further, if during the preset detection period before a transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as not-clear is larger than a preset value, continue performing through the communication circuit the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the allocated transmission period.

The processor may further acquire from a control signal transmitted from a base station the information of assigned frequency resource segments and assigned transmission periods.

The processor may perform energy detection on the at least one sub-channel and thus acquire the signal energy in the at least one sub-channel. If the signal energy is not higher than a preset threshold value, the sub-channel is idle.

Still another technical solution adopted by the disclosure is to provide a base station. The base station may comprise a processor and a transceiver. The processor may: receive through the transceiver a frequency resource segment indicator (FRSI) from at least one neighboring cell used to indicate the assignment information of the frequency resources of the unlicensed spectrum in the at least one neighboring cell； and assign the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell.

The processor may also periodically or aperiodically inform through the transceiver the FRSI of the present cell to the at least one neighboring cell.

The assignment information may comprise the segmenting and/or grouping information of the frequency resources of the unlicensed spectrum. The processor may segment and/or group the frequency resources of the unlicensed spectrum of the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell and thus derive the frequency resource segments or frequency resource segment groups for the present cell.

The processor may further assign through the transceiver the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell, enabling that the frequency resource segments or frequency resource segment groups assigned to the at least one UE within the present cell do not overlap with those assigned to at least one UE within each of the at least one neighboring cell.

The processor may further: acquire an LBT failure rate indicator (LFRI) from at least one neighboring cell used to indicate a failure rate of the LBT procedures corresponding to the frequency resource segments or frequency resource segment groups； and at least re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI, or adjusting through the transceiver the transmission power or detection parameters of UEs within the present cell, based on the relevant information provided by the LFRI.

The processor may also periodically or aperiodically inform through the transceiver the LFRI of the present cell to the at least one neighboring cell.

The processor may re-segment and/or re-group the frequency resources of the present cell based on the relevant information provided by the LFRI； and/or re-assign the frequency resource segments or frequency resource segment groups among the UEs within the present cell based on the relevant information provided by the LFRI.

The present disclosure may have the following advantages over the prior art: the UE may perform the CCA only on the corresponding sub-channels of the frequency resource segments in the assigned frequency resource segment group, while in the prior art the UE may perform the CCA on the entire bandwidth of the unlicensed spectrum used by the present cell. Thus, the present disclosure can narrow the bandwidth requiring the CCA detection, and thus can reduce the blocking probability among intra-cell and inter-cell UEs during the LAA uplink transmission, and can further enable the intra-cell frequency-division multiplexing (FDM) for the uplink transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart illustrating a first embodiment of an uplink transmission method using unlicensed spectrum according to the disclosure.

FIG. 2 illustrates performing a clear channel assessment (CCA) on frequency resource segments according to the embodiment as shown in FIG. 1.

FIG. 3 illustrates performing the CCA on the entire bandwidth according to the prior art.

FIG. 4 shows a flowchart illustrating a second embodiment of an uplink transmission method using unlicensed spectrum according to the disclosure.

FIG. 5 illustrates the transmission of reservation signals in an uplink transmission method using unlicensed spectrum according to an embodiment of the disclosure.

FIG. 6 illustrates re-performing the CCA after a transmission failure in an uplink transmission method using unlicensed spectrum according to an embodiment of the disclosure.

FIG. 7 illustrates continuing the CCA after a transmission failure in an uplink transmission method using unlicensed spectrum according to an embodiment of the disclosure.

FIG. 8 shows a flowchart illustrating a first embodiment of a resource assignment method using unlicensed spectrum according to the disclosure.

FIG. 9 shows a flowchart illustrating an embodiment of a resource assignment method using unlicensed spectrum according to the disclosure.

FIG. 10 illustrates the assignment of frequency resources of the unlicensed spectrum among the present cell not based on a frequency resource segment indicator (FRSI) of the neighboring cell according to the prior art.

FIG. 11 illustrates the assignment of frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell according to the first embodiment of the resource assignment method.

FIG. 12 shows a flowchart illustrating a second embodiment of a resource assignment method using unlicensed spectrum according to the disclosure.

FIG. 13 shows a flowchart illustrating an embodiment of a resource assignment method using unlicensed spectrum according to the disclosure.

FIG. 14 shows a block diagram of a first embodiment of a user equipment (UE) according to the disclosure.

FIG. 15 shows a block diagram of a second embodiment of a UE according to the disclosure.

FIG. 16 shows a block diagram of a UE according to an embodiment of the disclosure.

FIG. 17 shows a block diagram of a UE according to another embodiment of the disclosure.

FIG. 18 shows a block diagram of a UE according to yet another embodiment of the disclosure.

FIG. 19 shows a block diagram of a first embodiment of a base station according to the disclosure.

FIG. 20 shows a block diagram of a second embodiment of a base station according to the disclosure.

FIG. 21 shows a block diagram of an embodiment of a base station according to the disclosure.

FIG. 22 shows a block diagram of a third embodiment of a base station according to the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

FIG. 1 is a flowchart illustrating a first embodiment of an uplink transmission method using unlicensed spectrum. The uplink transmission method can be implemented on a user equipment (UE) . The UE can be stationary or mobile, including cellular phones, personal digital assistants (PDA) , wireless modems, tablet computers, notebook computers, cordless phones, and so forth. The uplink transmission method may comprise a listen-before-talk (LBT) procedure, and may comprise the following steps.

In a first step S11, a clear channel assessment (CCA) is carried out on sub-channels corresponding to frequency resource segments in a frequency resource segment group assigned to the UE, in order to determine whether the sub-channels are clear. Each sub-channel may correspond to one unique frequency resource segment.

The frequency resource segment group may be derived by segmenting and grouping the unlicensed spectrum, and may comprise at least one frequency resource segment. Each frequency resource segment may comprise at least one resource block (RB) or sub-carrier in the frequency domain. If a frequency resource segment comprises at least two RBs or sub-carriers, the RBs or sub-carriers can be continuous in the frequency domain. Each frequency resource segment group can comprise at least one frequency resource segment. When a frequency resource segment group comprises at least two frequency resource segments, they can be continuous or non-continuous in the frequency domain.

Typically, the UE can acquire from a control signal transmitted from a base station the information of the assigned frequency resource segment group. The base station can be connected to a core network and can perform wireless communications with the UE, thus providing communication coverage for the corresponding geographical area. The base station can include, but not limited to, macro base stations, micro base stations, or pico base stations. In some embodiments, a base station can also be interchangeably referred to as a wireless base station, an access point, a Node B, an evolved Node B (eNodeB or eNB) , and so forth.

The CCA can be carried out on part or all of the frequency resource segments in the assigned frequency resource segment group. A clear sub-channel means it can be used by the UE to transmit data. If the UE’s CCA results indicate that a sub-channel is being occupied, the UE may determine that this sub-channel is not clear； otherwise if the CCA results indicate that the sub-channel is currently idle, the UE can directly determine this sub-channel to be a clear one, or the UE may decide it is not clear and proceed with the CCA procedures only until the preset conditions are satisfied will the UE decide it is a clear sub-channel. The preset conditions can be that the duration of the sub-channel as idle is not shorter than a preset threshold value, or that an assigned transmission period has begun.

In one embodiment, the CCA may be implemented in the form of energy detection, i.e., by detecting the signal energy in the sub-channels measured. If the signal energy is not higher than the preset threshold value, the sub-channel is idle； otherwise the sub-channel is occupied or will be occupied. The CCA procedure may only consider whether there are signals transmitted in the sub-channels, and may neglect the types of the transmitted signals.

To acquire an accurate detection, a longer period can be configured for the CCA procedures. For example, each RB may typically comprise 180KHz in the frequency domain, thus when performing the energy detection on each RB, the detection period should be no less than 5.6μs, i.e., 1/180KHz. Filters, such as notch filters or finite impulse response (FIR) filters can be used to obtain the signal energy in the sub-channels detected. Fast Fourier Transformation (FFT) can also be used to obtain the signal energy in the sub-channel corresponding to each frequency resource segment.

In other embodiments, the CCA procedure can also be implemented in the form of “carrier-sense” , i.e., by detecting whether the signals containing the preset information are present in the detected sub-channel, if the result is negative, the sub-channel is idle, otherwise it is occupied or will be occupied. The preset information can be that indicating a type of a signal. The carrier-sense process may require processing and recognizing the detected signals. The CCA procedure can also use a combination of the energy detection method and the carrier-sense method, i.e., simultaneously detect the signal energy in the sub-channel and whether the signals containing the preset information are present. If the signal energy is not higher than the preset threshold value and no signals containing the present information are present, the sub-channel is idle； otherwise the sub-channel is occupied or will be occupied. The method may proceed to step S12.

In the following step S12, when at least one sub-channel corresponding to the frequency resource segments is clear, at least one clear sub-channel will be used for uplink transmission.

Part or all of the clear sub-channels may be used for uplink transmission.

For example, referring now to FIG. 2, the UE1 is assigned a frequency resource segment group A, which comprises frequency resource segments A1, A2, and A3； the UE2 is assigned a frequency resource segment group B, which comprises frequency resource segments B1, B2, and B3. The frequency resource segment groups allocated to the UE1 and UE2 do not overlap with each other. The CCA procedure may be performed on the frequency resource segments of the respective frequency resource segment groups A and B. The UE1 may be using the frequency resource segment group A to transmit data when the UE2 is performing the CCA procedures. Because the UE2 may perform the CCA procedure only on the frequency resource segment group B, which would not be interfered by the UE1, thus the UE2 would be able to use the frequency resource segment group B to transmit data.

While in the prior art, referring now to FIG. 3, in which the UE3 is assigned a frequency resource segment group C, which comprises frequency resource segments C1, C2, and C3； the UE4 is assigned a frequency resource segment group D, which comprises frequency resource segments D1, D2, and D3. The frequency resource segment groups C and D respectively assigned to the UE3 and U4 do not overlap with each other, but the CCA procedure is carried out across the entire bandwidth of the unlicensed spectrum used by the governing cell. Thus, when the UE4 is performing the CCA procedure across the entire bandwidth while the UE3 is using the frequency resource segment group C to transmit data, the UE4 may detect the signals transmitted by UE3, and thus decide that the sub-channel is occupied or will be occupied and cannot be used.

In the prior art, a channel detection mechanism referred to as Frame-Based Equipment (FBE) is proposed, in which one LBT procedure is carried out at a fixed position of a preset cycle. If the sub-channel is detected as idle, the transmitting entity can occupy the sub-channel immediately； otherwise, the transmitting entity cannot use this cycle, and may initiate another LBT procedure at the fixed position of the next cycle. The FBE mechanism may be easy to implement, and well compatible with the frame structure of existing cellular communication systems. And in terms of uplink transmission, different user equipment (UE) within a same cell can perform the LBT procedures simultaneously, which can enable the frequency-division multiplexing (FDM) and thus can reduce the intra-cell blocking probability. However, it cannot solve the blocking problem existing among the UEs as shown in FIG. 3. Though it is proposed that the UE does not transmit data or only transmit special signals in the portion of transmission period parallel with the corresponding LBT procedure, so as to provide chance for other UEs within the same cell to perform the LBT procedures, this, however, may reduce the total actual transmission time and thus the transmission efficiency. In addition, the FBE mechanism cannot address the blocking problem among the UEs belonging to asynchronous cells. And the fixed and limited period for execution of the LBT procedures may reduce the competitiveness versus the UEs belonging to other cells or other wireless communication equipment operating on the common unlicensed spectrum, which may adversely affect the UE’s unlink channel access probability.

According to the above embodiment, the UE may perform the CCA procedures only on the sub-channels corresponding to the frequency resource segments in the assigned frequency resource segment group, while in the prior art the UE may perform the CCA on the entire bandwidth of the unlicensed spectrum used by the present cell. Thus, the disclosure can narrow the bandwidth requiring the CCA detection. And the occupation of the frequency resources outside the assigned frequency resource segment group will not interfere with the UE’s CCA procedures, which thus can reduce the blocking probability among the LBT procedures of intra-cell and inter-cell UEs, thereby improving the channel access probability. Furthermore, if during the LAA uplink transmission the FDM technology is applied, and the base station further assign the UEs with frequency resource segment groups which don not overlap with each other, then the blocking problem among the LBT procedures of intra-cell UEs would no longer exist.

FIG. 4 illustrates a second embodiment of the uplink transmission method using unlicensed spectrum, which is based on the first embodiment uplink transmission method and further defines the step S11. The step S11 may comprise the following sub-steps.

In a first sub-step S110, a random number is selected from a contention window.

The size of the contention window can be bounded by a preset maximum and minimum value, for example, [1, 3] . The size of the contention window can be determined by at least one of the importance of the uploaded data, the upload waiting time, the traffic load condition, and the historical listen-before-talk (LBT) failure rate. The size of the contention window can be fixed or variable. The smaller the size of the contention window, the more aggressive and the larger the channel access probability.

The random number can directly indicate the length of time, for example, “20” may represent 20μs, or can be multiplied with a unit length to calculate the length of time, for example, “2” may represent 2 unit lengths of time.

In the following sub-step S120, the CCA procedure is carried out within a preset detection period before an assigned transmission period.

One or more transmission periods can be scheduled to the UE, when at least two transmission periods are scheduled to the UE, the transmission periods can be continuous or non-continuous in the time domain. Each transmission period can comprise, but not limited to, a sub-frame, a time slot, or a symbol. Typically, the UE can acquire from a control signal transmitted from the base station the information of the assigned transmission periods.

The UE can acquire the preset detection period information from a control signal transmitted from the base station, or autonomously configure the preset detection period. The preset detection period can be determined based on at least one of the importance of the uploaded data, the upload waiting time, the traffic load condition, and the historical listen-before-talk (LBT) failure rate. If the carrier-sense method is employed for the CCA procedure, and the detected signals contain the signal transmission duration information, then the signal transmission duration information can be taken into account in the setting of the preset detection period.

It can be easily concluded that the longer the preset detection period, then the earlier the CCA procedure will be started, the more aggressive and the bigger the channel access probability.

In the following sub-step S130, if duration of the sub-channel detected as idle is not shorter than the duration represented by the random number, the sub-channel is clear.

Typically, when the UE performs a CCA on the sub-channel and decides it is idle, then the time spent in this CCA will be cumulated to the duration； if the sub-channel is being occupied, the duration may remain unchanged or may be cleared or reset. The above process may be repeated only until the duration is not shorter than that represented by the random number will the CCA procedure be stopped, and the sub-channel will be determined as a clear sub-channel.

If the period for performing every CCA is fixed, then the number can be an integer indicating the times that the sub-channel is detected as idle. For example, first a loop flag bit can be set, whose value may be initialized to a random number. If the sub-channel is determined as idle in a CCA procedure, the value of the loop flag bit will be decremented by one； otherwise, if the sub-channel is being occupied, the value of the loop flag bit may remain unchanged or may be re-initialized to a random number. The above process may be repeated only until the value of the loop flag bit reaches zero will the CCA procedure be stopped, and the sub-channel will be determined as a clear sub-channel. Alternatively, the value of the loop flag bit can first be initialized to zero, and the sub-channel will be determined as a clear sub-channel and the CCA procedure will be stopped only when its value is no smaller than the random number.

According to the above embodiment, the LBT procedure with random back-off can, when compared with the FBE mechanism in which the LBT procedure is carried out at a fixed time, improve the competitiveness with the UEs belonging to other cells and other wireless communication equipment operating on the common unlicensed spectrum. In addition, the preset detection period and/or the size of the contention window can be flexibly adjusted in order to change the competitiveness for the uplink transmission. Because carrier-sense multiple access/collision avoidance (CSMA/CA) mechanism employed by Wi-Fi is essentially equivalent to the LBT procedure with random back-off, thus the above embodiment can allow the friendly and fair coexistence of LAA and Wi-Fi on the unlicensed spectrum.

In other embodiments, however, the LBT procedure without random back-off may be used, rather, when the duration of the sub-channel being detected as idle is not shorter than the preset threshold value, the sub-channel will be determined as a clear sub-channel.

Referring now to FIG. 5, which shows a resource assignment method using the unlicensed spectrum according to an embodiment, in which if there is a time interval between after determination of the sub-channel is evaluated as clear and a start of the corresponding assigned transmission period, the UE may use this sub-channel to transmit reservation signals during the time interval. The present embodiment can be combined with any embodiment of the resource assignment method using the unlicensed spectrum according to the disclosure.

The reservation signals can be those used to indicate that the sub-channel is being occupied or will be occupied so that it cannot be used to transmit data. The reservation signals may also contain part of the data to be uploaded or other information that needs to be sent to the base station.

Thus, after the UE decides that the sub-channel is clear, it can transmit reservation signals in order to occupy the sub-channel before the start of the corresponding transmission period, thus avoiding that the sub-channel is occupied by other equipment before the start of the transmission period, causing the UE to be not able to transmit data over this sub-channel. Obviously, the present embodiment can further improve the UE’s channel access probability.

In one embodiment, the UE may be scheduled with at least two transmission periods, which can be continuous or non-continuous. The UE may perform, during a previous transmission period, the CCA procedure on the sub-channels corresponding to the frequency resource segments of the assigned frequency resource segment group, where each sub-channel may correspond to one unique frequency resource segment. If the number of the frequency resource segments corresponding to the sub-channels evaluated as non-clear is larger than a preset value, then the UE fails on the previous transmission period, i.e., the UE cannot upload data during the previous transmission period. The preset value can be determined by the base station, and the UE can acquire the preset value from a control signal transmitted from the base station. The preset value can also be determined by the UE. The smaller the preset value, the lower the channel access probability.

The UE may then re-perform the CCA procedure on the sub-channels corresponding to the frequency resource segments during the preset detection period before the subsequent transmission period, and determine whether these sub-channels are clear. The sub-channels that will receive the CCA procedures during the subsequent transmission period may be the same with or different from those during the previous transmission period. For example, part of the sub-channels may be determined as clear by the UE during the previous transmission period, and the UE may transmit reservation signals using the clear sub-channels, then during the CCA within the subsequent transmission period, the sub-channels already determined clear in the previous transmission period may not be evaluated again. Alternatively, the UE may not evaluate the sub-channels, which have been evaluated as non-clear in the previous transmission period, during the CCA in the subsequent transmission period. Alternatively, the UE may further evaluate the sub-channels, having not yet been evaluated in the previous transmission period, during the CCA in the subsequent transmission period.

The CCA procedures performed in the subsequent transmission period may use the same or different detection parameters from those used in the CCA procedures in the previous transmission period. The detection parameters may comprise a size of the contention window and/or the preset detection period. The UE can acquire the detection parameters from a control signal transmitted from the base station, or can autonomously determine the detection parameters. Typically, to improve the channel access probability, the detection parameters used in the CCA procedures of the subsequent transmission period may be more aggressive than those used in the CCA procedures of the previous transmission period. That is, compared with the CCA procedures in the previous transmission period, the CCA procedures in the subsequent transmission period may use a smaller-size contention window, or set a longer preset detection period.

Referring now to FIG. 6, in which the UE5 is scheduled with 3 continuous sub-frames in the time domain, and assigned with three frequency resource segments E1, E2, and E3 in the frequency domain. The CCA procedures are performed on the sub-channels corresponding to E1, E2, and E3 during the preset detection period before the first sub-frame, where E1 and E2 are clear sub-channels, while E3 is non-clear. The preset value used to determine whether the UE5 can transmit data is "0" , which means that the UE5 can only transmit data when the sub-channels corresponding to all the frequency resource segments are clear. The UE5 fails on the first sub-frame, i.e., it cannot transmit data during the first sub-frame, and then re-determine, during the preset detection period before the second sub-frame, whether the sub-channels corresponding to all the frequency resource segments are clear. As it turns out, the sub-channels corresponding to E1, E2, and E3 are all clear in the second sub-frame, thus the UE5 can use the second and third sub-frames to transmit data.

In another embodiment, the UE may perform, during a transmission period, the CCA procedure on the sub-channels corresponding to the frequency resource segments of the assigned frequency resource segment group, where each sub-channel may correspond to one unique frequency resource segment. If the number of the frequency resource segments corresponding to the sub-channels evaluated as non-clear is larger than a preset value, then the UE fails on the current transmission period, i.e., the UE cannot upload data since the beginning of the current transmission period. The preset value can be determined by the base station, and the UE can acquire the preset value from a control signal transmitted from the base station. The preset value can also be determined by the UE. The smaller the preset value, the lower the channel access probability. The UE may then continue the CCA on the sub-channels corresponding to the frequency resource segments within this transmission period, to determine whether these sub-channels are clear, if the number of the frequency resource segments corresponding to the sub-channels evaluated as non-clear is not greater than a preset value, then the UE can transmit data during the remaining portion of the current transmission period, or can transmit reservation signals over the clear sub-channels until the beginning of the subsequent transmission period.

Referring now to FIG. 7, the UE6 is scheduled with 3 continuous sub-frames in the time domain, and assigned with three frequency resource segments F1, F2, and F3 in the frequency domain. The CCA procedures are performed on the sub-channels corresponding to F1, F2, and F3 during the preset detection period before the first sub-frame, where F1 is a clear sub-channel, while F2 and F3 are non-clear. The preset value used to determine whether the UE6 can transmit data is "0" , which means that the UE6 can only transmit data when the sub-channels corresponding to all the frequency resource segments are clear. The UE6 fails on the first sub-frame, i.e., it cannot transmit data during the first sub-frame. The UE 6 may continue the CCA procedure within the first sub-frame, and may detect at time t1 that the sub-channels corresponding to the F1, F2, and F3 are all clear, thus the UE6 may transmit reservation signals since t1 until the beginning of the second sub-frame, and thus further use the second and third sub-frames to transmit data.

FIG. 8 is a flowchart illustrating a resource assignment method using unlicensed spectrum according to an embodiment. The method can be implemented on a base station. The embodiment can comprise the following steps.

In a first step S21, the base station receives a frequency resource segment indicator (FRSI) that is transmitted from at least one neighboring cell.

The base station can receive the FRSI from a base station of the neighboring cell through X2 process. The FRSI is used to indicate the assignment information of the frequency resources of the unlicensed spectrum of the associated neighboring cell. Typically, the assignment information may comprise the segmenting and/or grouping information of the frequency resources of the unlicensed spectrum. The assignment information can further include the information of the UEs, to which the resulting frequency resource segments or frequency resource segment groups are assigned. The method may proceed to step S22.

In the following step S22, the base station assigns the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell.

Referring to FIG. 9, in one embodiment, the resource assignment method may further comprise a step S211, in which the base station may also periodically or aperiodically inform the FRSI of the present cell to the at least one neighboring cell through X2 process. The step S211 can be performed simultaneously with the step S21, or at any moment before or after the execution of the step S21. Typically, the base station may segment and/or group the frequency resources of the unlicensed spectrum used by the present cell and thus obtain the frequency resource segments or frequency resource segment groups based on the relevant information provided by the FRSI, eliminating or at least reducing the overlaps between the frequency resource segments or frequency resource segment groups used by the present cell and those used by the at least one neighboring cell. Typically, the frequency resources may be segmented and/or grouped in exactly or partially identical manner with the at least one neighboring cell.

In addition, the base station may assign the frequency resource segments or frequency resource segment groups to user equipment (UE) within the present cell, ensuring that the frequency resource segments or frequency resource segment groups assigned to at least one UE within the present cell do not overlap with those assigned to at least one UE within the at least one neighboring cell.

For example, referring now FIG. 10, the frequency resources of the unlicensed spectrum in the cell 1 are divided into three groups G, H, and I, while those of the cell 2 are divided into three groups J, K, and L. Because the cell 2 does not assign its frequency resources of the unlicensed spectrum based on the relevant information provided by the FRSI from the cell 1, each frequency resource segment group G or H or I is actually overlapped with the frequency resource segment group J or K or L, thus when the UE, assigned with any one of G, H, and I, is transmitting data, it will interfere with the LBT procedures of UE assigned with any one of J, K, and L, and vice versa.

In another example, referring now to FIG. 11, the frequency resources of the unlicensed spectrum of the cell 1 are still divided into three groups G, H, and I, while the frequency resources of the unlicensed spectrum of the cell 3 are divided into three groups M, N, and O, and the frequency resources of the unlicensed spectrum of the cell 4 are divided into two groups P and Q. The cells 3 and 4 assign their respective frequency resources based on the relevant information provided by the FRSI of the cell 1, so that G is not overlapped with any one of N, O, and Q. Thus, when the UE, assigned with the frequency resource segment group G, is transmitting data, it may only interfere with the LBT procedures of the UE assigned with M and P, but will not interfere with the LBT procedures of the UE assigned with any other frequency resource segment groups. Likewise, the situations related to other frequency resource segment groups can also be acquired.

According to the above embodiment, the base station can assign the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI of the at least one neighboring cell, which thus can at least reduce the overlaps between the frequency resource segments or frequency resource segment groups used by the present cell and those used by the at least one neighboring cell, thus effectively reducing the blocking probability among the LBT procedures of inter-cell UEs.

FIG. 12 illustrates a second embodiment of the resource assignment method using unlicensed spectrum, which is based on the first embodiment resource assignment method and further comprises the following steps.

In a first extra step S23, an LBT failure rate indicator (LFRI) is acquired.

The LFRI is used to indicate the failure rate of the LBT procedures corresponding to the frequency resource segment groups or frequency resource segments of the associated cell. The LFRI can be that of the present cell and/or that of the neighboring cell which is received through the X2 process.

In a second extra step S24, the frequency resources of the present cell are re-assigned based on the relevant information provided by the LFRI, and/or the transmission power or detection parameters of the UEs within the present cell are adjusted, based on relevant information provided by the LFRI.

Referring now to FIG. 13, in one embodiment, the resource assignment method may further comprise a step S231, in which the base station may also periodically or aperiodically inform the LFRI of the present cell to the at least one neighboring cell through X2 process. The step S231 can be performed simultaneously with the step S23, or at any moment before or after the execution of the step S23.

The base station may perform at least one of the following three operations: re-segmenting and/or re-grouping the frequency resources of the present cell based on the relevant information provided by the LFRI； re-assigning the frequency resource segment groups or frequency resource segments to the UEs within the present cell； and adjusting the transmission power or detection parameters of the UEs within the present cell based on the relevant information provided by the LFRI.

For example, if the base station finds that a certain frequency resource segment or frequency resource segment group, when compared with an identical frequency resource segment or frequency resource segment group in the neighboring cell or with other frequency resource segments or frequency resource segment groups, leads to an unusually high unlink LBT failure rate, it may be likely that this frequency resource segment or frequency resource segment group has been assigned to the neighboring UEs, causing the LBT block. The base station may then perform at least one of the following three operations: re-segmenting and/or re-grouping the frequency resources； re-assigning the frequency resource segment groups or frequency resource segments to the UEs within the present cell； and reducing the transmission power. In addition, if the base station finds that a certain frequency resource segment or frequency resource segment group used by the present cell has an unusually high uplink LBT failure rate (including the base station can or cannot receive the LFRI from the neighboring cell) , then there may be other wireless communication equipment (such as Wi-Fi equipment) using the common frequency resource segment or frequency resource segment group, or there may exist other UEs, whose timing is slightly ahead of the present cell, that cause the block to the LBT procedure of the UEs within the present cell. The base station can modify the detection parameters of the corresponding UE, to make it more aggressive. For example, the base station can reduce the size of the contention window and/or lengthen the preset detection period, thus improving the channel access probability of the corresponding UE and thereby reducing the blocking probability among the LBT procedures.

According to the above embodiment, the base station can re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI, which can thus improve the competitiveness of the UEs within the present cell, further reducing the blocking probability among the LBT procedures.

Referring now to FIG. 14, a piece of UE according an embodiment may comprise a detection module 11 and an upload module 12.

The detection module 11 may be configured to perform a clear channel assessment (CCA) on sub-channels corresponding to frequency resource segments of an assigned frequency resource segment group, and thus determine whether the sub-channels are clear, wherein the frequency resource segment group may be derived by segmenting and grouping an unlicensed spectrum and comprise at least one such frequency resource segment, and each sub-channel may correspond to one unique frequency resource segment.

The upload module 12 may be configured to, when at least one sub-channel corresponding to the frequency resource segments is clear, use at least one clear channel for uplink transmission.

The various modules of the current embodiment UE may be configured to execute the corresponding steps of the first embodiment uplink transmission method, as shown in FIG. 1； see FIG. 1 and relevant description for details.

According to the above embodiment, the UE may perform the CCA procedure only on the sub-channels corresponding to the frequency resource segments in the assigned frequency resource segment group, while in the prior art the UE may perform the CCA on the entire bandwidth of the unlicensed spectrum used by the present cell. Thus, the disclosure can narrow the bandwidth requiring the CCA procedure. And the occupation of the frequency resources outside the assigned frequency resource segment group will not interfere with the UE’s CCA procedures, which thus can reduce the blocking probability among the LBT procedures carried out by intra-cell and inter-cell UEs, thus improving the channel access probability. If during the LAA uplink transmission the frequency-division multiplexing (FDM) technology is applied, and the base station further assigns the UEs with frequency resource segment groups, which don not overlap with each other, then the blocking problem among the LBT procedures of intra-cell UEs would no longer exist.

Referring now to FIG. 15, which illustrates a block diagram of a second embodiment of the UE, which is based on the first embodiment UE and further comprises an acquisition module 13 configured to acquire from a control signal sent from a base station the information of the assigned frequency resource segments and the scheduled transmission periods.

The detection module 11 may comprise a front detection unit 111 configured to perform the CCA within a preset detection period before an assigned transmission period. The front detection unit 111 may comprise:

a selection sub-unit 121 configured to select a random number from a contention window；

a detection sub-unit 122 configured to repeatedly perform the CCA on the sub-channels during the preset detection period before the assigned transmission period； and

a determination sub-unit 123 configured to, when duration of a sub-channel detected as idle is not shorter than the duration represented by the random number, determine that the sub-channel is clear.

The various modules of the current embodiment UE may be configured to execute the corresponding steps of the second embodiment uplink transmission method, as shown in FIG. 4； see FIG. 4 and relevant description for details.

According to the above embodiment, the LBT procedure with random back-off can, when compared with the FBE mechanism in which the LBT procedure is carried out at a fixed time, improve the competitiveness versus the UEs belonging to other cells and other wireless communication equipment operating on the common unlicensed spectrum. In addition, the preset detection period and/or the size of the contention window can be flexibly adjusted in order to change the competitiveness for the uplink transmission. Because the carrier-sense multiple access/collision avoidance (CSMA/CA) mechanism employed by Wi-Fi is essentially equivalent to the LBT procedure with random back-off, the above embodiment can allow the friendly and fair coexistence of LAA and Wi-Fi operating on the common unlicensed spectrum.

Referring now to FIG. 16, in one embodiment, the detection module 11 may further comprise a re-detection unit 112 configured to, if during the preset detection period before a previous transmission period a number of the frequency resource segments in the frequency resource segment group that correspond to the sub-channels evaluated as non-clear is larger than a preset value, re-perform the CCA on the sub-channels corresponding to the frequency resource segments within the preset detection period before a subsequent transmission period.

Typically, the CCA of the subsequent transmission period may use the same or more aggressive detection parameters than the CCA of the previous transmission period. The detection parameters may comprise a size of the contention window and/or the preset detection period. The detection parameters may be acquired from a control signal transmitted from the base station, or autonomously determined by the UE. Namely, compared with those used in the CCA procedures in the previous transmission period, in the subsequent transmission period the size of the used contention window may be smaller, and/or the previous transmission period may be longer.

Referring now to FIG. 17, in one embodiment, the detection module 11 may further comprise a continue-detection unit 113 configured to, if during the preset detection period before a transmission period a number of the frequency resource segments in the frequency resource segment group that correspond to the sub-channels evaluated as non-clear is larger than a preset value, continue performing the CCA on the sub-channels corresponding to the frequency resource segments within this transmission period. If the number of the frequency resource segments corresponding to the sub-channels evaluated as non-clear is not greater than a preset value, then the UE can transmit data during the remaining portion of the current transmission period, or can transmit reservation signals over the clear sub-channels until the beginning of the subsequent transmission period.

Referring now to FIG. 18, there is shown a block diagram of a third embodiment of the UE. The UE may comprise a processor 110 and a communication circuit 120. The processor 110 may be connected to the communication circuit 120 via a bus.

The communication circuit 120 may be configured to transmit and receive data, and may act as an interface through which the UE communicates with other communication equipment.

The processor 110 may control the operations of the UE, and can also be referred to as a central processing unit (CPU) . The processor 110 can be an integrated circuit chip with signal processing capabilities. The processor 110 may also be a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) , or other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components. The general purpose processor can be a microprocessor or any conventional processor.

The UE may further include a memory storage (not shown) used to store the commands and data necessary for operations of the processor 110. The memory storage can also store the data received by the communication circuit 120.

The processor 110 may be configured to: perform through the communication circuit 120 a clear channel assessment (CCA) on sub-channels corresponding to frequency resource segments of an assigned frequency resource segment group, and thus determine whether the sub-channels are clear, wherein the frequency resource segment group may be derived by segmenting and grouping an unlicensed spectrum； and, when at least one sub-channel corresponding to the frequency resource segments is clear, use at least one clear sub-channel for uplink transmission through the communication circuit 120.

Furthermore, the processor 110 may perform through the communication circuit 120 the CCA within a preset detection period before an assigned transmission period.

The processor 110 may further, when there is a time interval between after determination of a sub-channel is evaluated as clear and a start of the assigned transmission period, use the sub-channel to transmit reservation signals through the communication circuit 120 within the time interval. The reservation signals may be used to indicate that the sub-channel is occupied or will be occupied.

The processor 110 may: select a random number from a contention window； repeatedly perform through the communication circuit 120 the CCA on the sub-channels within the preset detection period before the assigned transmission period； and determine, if a duration of the sub-channel as idle is not shorter than the duration represented by the random number, that the sub-channel is clear.

In addition, a size of the contention window can be determined by at least one of the importance of the uploaded data, the upload waiting time, the traffic load condition, and the historical listen-before-talk (LBT) failure rate.

The processor 110 may further acquire through the communication circuit 120 the detection parameters from a base station, or autonomously determine the detection parameters.

The processor 110 may further re-perform, if during the preset detection period before a previous transmission period a number of the frequency resource segments in the assigned frequency resource segment group that correspond to the sub-channels evaluated as non-clear is larger than a preset value, through the communication circuit 120 the CCA on the sub-channels corresponding to the frequency resource segments within the preset detection period before a subsequent transmission period.

Typically, the CCA of the subsequent transmission period may use the same or more aggressive detection parameters than the CCA of the previous transmission period. The detection parameters may comprise a size of the contention window and/or of the preset detection period.

The processor 110 may further continue, if during the preset detection period before a transmission period a number of the frequency resource segments in the frequency resource segment group that correspond to the sub-channels evaluated as non-clear is larger than a preset value, performing through the communication circuit 120 the CCA on the sub-channels corresponding to the frequency resource segments within this transmission period.

The processor 110 may further acquire from a control signal transmitted from a base station the information of assigned frequency resource segments and assigned transmission periods.

The processor 110 may perform through the communication circuit 120 energy detection on the sub-channels and thus acquire the signal energy value on the corresponding sub-channel. If the signal energy is not higher than a preset threshold value, the sub-channel is idle.

Referring now to FIG. 19, which illustrates a first embodiment of a base station, comprising a receiving module 21 and an assignment module 22.

The receiving module 21 may be configured to receive a frequency resource segment indicator (FRSI) from at least one neighboring cell, which is used to indicate the assignment information of the frequency resources of the unlicensed spectrum among the at least one neighboring cell.

The assignment module 22 may be configured to assign the frequency resources of the unlicensed spectrum among present cell based on the FRSI.

The assignment information may comprise the segmenting and/or grouping information of the frequency resources of the unlicensed spectrum. The assignment module 22 may comprise a first assignment unit 221 configured to segment and/or group the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell and thus acquire frequency resource segments or frequency resource segment groups for the present cell.

The assignment module 22 may further comprise a second assignment unit 222 configured to assign the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell, guaranteeing that the frequency resource segments or frequency resource segment groups assigned to the at least one UE within the present cell do not overlap with those assigned to at least one UE within each of the at least one neighboring cell.

According to the above embodiment, the base station can assign the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI, which thus can at least reduce the overlaps between the frequency resource segments or frequency resource segment groups used by the present cell and those used by the at least one neighboring cell, thus effectively reducing the blocking probability among the LBT procedures of inter-cell UEs.

The various modules of the current embodiment base station may be configured to execute the corresponding steps of the first embodiment resource assignment method, as shown in FIG. 8, see FIG. 8 and relevant description for details.

Referring now to FIG. 20, which illustrates a second embodiment of a base station, which is based on the first embodiment base station, and further comprises an acquisition module 23 and an adjustment module 24.

The acquisition module 23 may be configured to acquire a listen-before-talk (LBT) failure rate indicator (LFRI) used on indicate a failure rate of LBT procedures corresponding to frequency resource segments or frequency resource segment groups.

The adjustment module 24 may be configured to re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI, and/or adjust the transmission power or detection parameters of the UEs within the present cell.

The various modules of the current embodiment base station may be configured to execute the corresponding steps of the second embodiment resource assignment method, as shown in FIG. 12； see FIG. 12 and relevant description for details.

According to the above embodiment, the base station can re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI, which can improve the competitiveness of the UEs within the present cell by reducing the interference between the UEs within the present cell and other UEs, thus further reducing the blocking probability among the LBT procedures.

Referring now to FIG. 21, in one embodiment, the base station may further comprise a transmitting module 25 configured to inform periodically or aperiodically the FRSI and/or the LFRI of the present cell to the at least one neighboring cell.

Referring now to FIG. 22, a third embodiment of a base station may comprise a processor 210 and a transceiver 220. The processor may be connected to the transceiver 220 via a bus.

The transceiver 220 may be configured to transmit and receive data, and may act as an interface through which the base station communicates with other communication equipment.

The processor 210 may control the operations of the base station, and can also be referred to as a central processing unit (CPU) . The processor 210 can be an integrated circuit chip with signal processing capabilities. The processor 210 may also be a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) , or other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components. The general purpose processor can be a microprocessor or any conventional processor.

The base station may further comprise a memory storage (not shown) used to store the commands and data necessary for operations of the processor 210. The memory storage can also store the data received by the transceiver 220.

The processor 210 may be configured to: receive through the transceiver 220 a frequency resources segment indicator (FRSI) transmitted from at least one neighboring cell and used to indicate assignment information of frequency resources of the unlicensed spectrum in the at least one neighboring cell； and assign the frequency resources of the unlicensed spectrum among present cell based on relevant information provided by the FRSI from the at least one neighboring cell.

The processor 210 may further inform through the transceiver 220 periodically or aperiodically the FRSI of the present cell to the at least one neighboring cell.

The assignment information may comprise the segmenting and/or grouping information of the frequency resources of the unlicensed spectrum. The processor 210 may segment and/or group the frequency resources of the unlicensed spectrum among the present cell based on the FRSI and thus derive the frequency resource segments or frequency resource segment groups for the present cell.

The processor 210 may further assign through the transceiver 220 the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell, guaranteeing that the frequency resource segments or frequency resource segment groups assigned to the at least one UE within the present cell do not overlap with those assigned to at least one UE within each of the at least one neighboring cell.

The processor 210 may further: acquire an LBT failure rate indicator (LFRI) used to indicate a failure rate of the LBT procedures corresponding to the frequency resource segments or frequency resource segment groups； re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI； and/or adjust through the transceiver 220 the transmission power or detection parameters of the UEs within the present cell.

The processor 210 may further inform through the transceiver 220 periodically or aperiodically the LFRI of the present cell to the at least one neighboring cell.

The processor 210 may: re-segment and/or re-group the frequency resources of the present cell based on the relevant information provided by the LFRI； and/or re-assign through the transceiver 220 the frequency resource segments or frequency resource segment groups among the UEs within the present cell based on the relevant information provided by the LFRI.

It should be appreciated that the disclosed user equipment, base stations, and methods can also be implemented in other forms. Rather, the base stations and UEs described are merely illustrative. For example, the division of modules or units is only a division based on logic functions, thus in actual implementations there may be other division manners, for example, multiple units or components may be combined or integrated onto another system, or some features may be ignored or not executed. In addition, the displayed or discussed mutual couplings, direct couplings or communication connections may be achieved through some interfaces, devices or units, and may be achieved electrically, mechanically or in other forms.

The separated units as described may or may not be physically separated. Components displayed as units may or may not be physical units, and may reside at one location or may be distributed to multiple networked units. Part or all of the units may be selected, according to actual requirements, to achieve the intended objectives.

In addition, various functional units in the disclosure may be integrated into one processing unit, and may be present as physically separated units, and two or more units may be integrated into one unit. The integrated units may be implemented by hardware, and may also be implemented as software functional units.

If the integrated units are implemented as software functional units and sold or used as standalone products, they can be stored in a computer readable storage medium. Thus, the substantial technical solution, or the part which contributes to the prior art, or all or part of the technical solution, of the disclosure, may be embodied as software products. The computer software products can be stored in a storage medium and can include multiple instructions enabling a computing device (for example, a personal computer, a server, a network device, etc. ) or a processor to execute all or part of the steps of the methods as described in the disclosure. The storage medium may include any kinds of medium that can store program codes such as, for example, a USB flash disk, a mobile hard drive, a read-only memory (ROM) , a random access memory (RAM) , a magnetic disk or an optical disk.

The above description is merely embodiments of the disclosure, but is not limiting the scope of the disclosure. Any equivalent structures or flow transformations made to the disclosure, or any direct or indirect applications of the disclosure on any other related fields, shall all be covered within the protection of the disclosure.

Claims

An uplink transmission method using unlicensed spectrum, comprising:

performing a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment of an assigned frequency resource segment group； and

determining whether the at least one sub-channel is clear, wherein the assigned frequency resource segment group is created by segmenting and grouping the unlicensed spectrum, and each sub-channel corresponds to a unique frequency resource segment； and

when the at least one sub-channel corresponding to the at least one frequency resource segment is clear, using at least one clear sub-channel for uplink transmission.
The uplink transmission method according to claim 1, wherein the block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment comprises:

performing the CCA on the at least one sub-channel within a preset detection period before an assigned transmission period.
The uplink transmission method according to claim 2, further comprising, before the block of using the at least one clear sub-channel for uplink transmission:

when there is a time interval between after determination the at least one sub-channel is evaluated as clear and before a start of the assigned transmission period, using the at least one clear sub-channel to transmit reservation signals during the time interval to indicate the at least one clear sub-channel is occupied or will be occupied.
The uplink transmission method according to claim 2, wherein the block of performing the CCA on the at least one sub-channel within the preset detection period before the assigned transmission period comprises:

selecting a random number from a contention window；

repeatedly performing the CCA on the at least one sub-channel during the preset detection period before the assigned transmission period； and

if a duration of the at least one sub-channel as idle is not shorter than a duration represented by the random number, determining that the at least one sub-channel is clear.
The uplink transmission method according to claim 4, wherein a size of the contention window is determined based on at least one of importance of data to be uploaded, an upload waiting time, a traffic load condition, and a historical listen-before-talk (LBT) failure rate.
The uplink transmission method according to claim 4, wherein the block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment further comprises:

if a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear during the preset detection period of a previous transmission period is greater than a preset value, re-performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment during the preset detection period of a subsequent transmission period.
The uplink transmission method according to claim 6, wherein the CCA of the subsequent transmission period uses the same or more aggressive detection parameters than the CCA of the previous transmission period.
The uplink transmission method according to claim 7, wherein the detection parameters comprise at least one of a size of the contention window and the preset detection period.
The uplink transmission method according to claim 7, wherein the detection parameters are acquired from a control signal transmitted from the base station, or autonomously determined.
The uplink transmission method according to claim 2, wherein the block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment further comprises:

if a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear during the preset detection period of the assigned transmission period is greater than a preset value, continuing performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the assigned transmission period.
The uplink transmission method according to claim 2, further comprising:

acquiring, from a control signal transmitted from a base station, information of the at least one assigned frequency resource segment and the assigned transmission period.
The uplink transmission method according to any one of claims 1-11, wherein the block of performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment of the assigned frequency resource segment group comprises:

performing energy detection on the at least one sub-channel；

acquiring signal energy in the at least one sub-channel； and

determining that the at least one sub-channel is idle when the signal energy is not higher than a preset threshold value.
A resource assignment method using unlicensed spectrum, comprising:

receiving a frequency resource segment indicator (FRSI) from at least one neighboring cell, which is used to indicate assignment information of frequency resources of the unlicensed spectrum in the at least one neighboring cell； and

assigning the frequency resources of the unlicensed spectrum among a present cell based on relevant information provided by the FRSI from the at least one neighboring cell.
The resource assignment method according to claim 13, further comprising:

informing periodically or aperiodically the FRSI of the present cell to the at least one neighboring cell.
The resource assignment method according to claim 13, wherein the assignment information comprises at least one of segmenting and grouping information of the frequency resources of the unlicensed spectrum； and the block of assigning the frequency resources of the unlicensed spectrum among the present cell based on relevant information provided by the FRSI from the at least one neighboring cell comprises at least one of segmenting and grouping the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell to acquire frequency resource segments or frequency resource segment groups for the present cell.
The resource assignment method according to claim 15, wherein the block of assigning the frequency resources of the unlicensed spectrum among the present cell based on relevant information provided by the FRSI from the at least one neighboring cell further comprises:

assigning the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell； and

ensuring that the frequency resource segments or frequency resource segment groups assigned to the at least UE within the present cell do not overlap with the frequency resource segments or frequency resource segment groups assigned to at least one UE within each of the at least one neighboring cell.
The resource assignment method according to claim 13, further comprising:

acquiring a listen-before-talk (LBT) failure rate indicator (LFRI) used to indicate a failure rate of LBT procedures corresponding to frequency resource segments or frequency resource segment groups； and at least

re-assigning the frequency resources within the present cell based on the relevant information provided by the LFRI, or adjusting transmission power or detection parameters of user equipment within the present cell, based on the relevant information provided by the LFRI.
The resource assignment method according to claim 17, further comprising:

informing periodically or aperiodically the LFRI of the present cell to the at least one neighboring cell.
The resource assignment method according to claim 17, wherein the block of re-assigning the frequency resources within the present cell based on the relevant information provided by the LFRI comprises at least one of:

at least repeating re-segmenting or re-grouping the frequency resources within the present cell based on the relevant information provided by the LFRI； and

re-assigning the frequency resource segments or the frequency resource segment groups among user equipment within the present cell based on the relevant information provided by the LFRI.
A user equipment (UE) , comprising:

a detection module configured to perform a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment of an assigned frequency resource segment group, and to determine whether the at least one sub-channel is clear, wherein the frequency resource segment group is created by segmenting and grouping an unlicensed spectrum, and each sub-channel corresponds to a unique frequency resource segment； and

an upload module configured to, when the at least one sub-channel corresponding to the at least one frequency resource segment is clear, use at least one clear sub-channel for uplink transmission.
The UE according to claim 20, wherein the detection module comprises a front detection unit configured to perform the CCA on the at least one sub-channel within a preset detection period before an assigned transmission period.
The UE according to claim 21, wherein the front detection unit comprises:

a selection sub-unit configured to select a random number from a contention window；

a detection sub-unit configured to repeatedly perform the CCA on the at least one sub-channel during the preset detection period before the assigned transmission period； and

a determination sub-unit configured to determine that the at least one sub-channel is clear when a duration of the at least one sub-channel as idle is not shorter than a duration represented by the random number.
The UE according to claim 22, wherein the detection module further comprises a re-detection unit configured to, when during the preset detection period before a previous transmission period, a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear is larger than a preset value, re-perform the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment during the preset detection period before a subsequent transmission period.
The UE according to claim 23, wherein the CCA of the subsequent transmission period uses the same or more aggressive detection parameters than the CCA of the previous transmission period, and the detection parameters comprise at least one of a size of the contention window and the preset detection period.
The UE according to claim 22, wherein the detection module further comprises a continue-detection unit configured to, when during the preset detection period before the assigned transmission period a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear is larger than a preset value, continue performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the transmission period.
The UE according to claim 21, further comprising:

an acquisition module configured to acquire, from a control signal transmitted from a base station, information of the at least one assigned frequency resource segment and the assigned transmission period.
A base station, comprising:

a receiving module configured to: receive a frequency resource segment indicator (FRSI) from at least one neighboring cell, which is used to indicate assignment information of frequency resources of unlicensed spectrum in the at least one neighboring cell； and

an assignment module configured to assign the frequency resources of the unlicensed spectrum among a present cell based on relevant information provided by the FRSI from the at least one neighboring cell.
The base station according to claim 27, wherein the base station further comprises a transmitting module configured to inform periodically or aperiodically the FRSI of the present cell to the at least one neighboring cell.
The base station according to claim 27, wherein the assignment information comprises at least one of segmenting and grouping information of the frequency resources of the unlicensed spectrum； and

the assignment module comprises a first assignment unit configured to at least segment or group the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell, and thus acquire frequency resource segments or frequency resource segment groups for the present cell.
The base station according to claim 29, wherein the assignment module further comprises a second assignment unit configured to assign the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell, ensuring that the frequency resource segments or frequency resource segment groups assigned to the at least one UE within the present cell do not overlap with the frequency resource segments or frequency resource segment groups assigned to at least one UE within each of the at least one neighboring cell.
The base station according to claim 27, further comprising:

an acquisition module configured to acquire a listen-before-talk (LBT) failure rate indicator (LFRI) used to indicate a failure rate of LBT procedures corresponding to frequency resource segments or frequency resource segment groups； and

a regulation module configured to at least re-assign the frequency resources within the present cell based on the relevant information provided by the LFRI, or adjusting transmission power or detection parameters of user equipment within the present cell, based on relevant information provided by the LFRI.
The base station according to claim 31, wherein the transmitting module is further configured to inform periodically or aperiodically the LFRI of the present cell to the at least one neighboring cell.
A user equipment (UE) , comprising a processor and a communication circuit connected to the processor； wherein

the processor is configured to:

perform through the communication circuit a clear channel assessment (CCA) on at least one sub-channel corresponding to at least one frequency resource segment of an assigned frequency resource segment group；

determine whether the at least one sub-channel is clear, wherein the frequency resource segment group is created by segmenting and grouping an unlicensed spectrum； and

when the at least one sub-channel corresponding to the at least one frequency resource segment is clear, use at least one clear sub-channel for uplink transmission through the communication circuit.
The UE according to claim 33, wherein the processor is configured to perform through the communication circuit the CCA on the at least one sub-channel within a preset detection period before an assigned transmission period.
The UE according to claim 34, wherein the processor is configured to, when there is a time interval between after determination the at least one sub-channel is evaluated as clear and before a start of the assigned transmission period, use the at least one clear sub-channel to transmit reservation signals during the time interval to indicate the at least one clear sub-channel is occupied or will be occupied.
The UE according to claim 34, wherein the processor is configured to:

select a random number from a contention window；

repeatedly perform the CCA on the at least one sub-channel within the preset detection period before the assigned transmission period； and

when a duration of the at least one sub-channel being detected as idle is not shorter than a duration represented by the random number, determine that the at least one sub-channel is clear.
The UE according to claim 36, wherein a size of the contention window is determined based on at least one of importance of the uploaded data, an upload waiting time, and a traffic load condition, and a historical LBT failure rate.
The UE according to claim 36, wherein the processor is configured to, when during the preset detection period before a previous transmission period a number of the at least one frequency resource segment of the assigned frequency resource segment group that corresponds to the at least one sub-channel evaluated as non-clear is larger than a preset value, re-perform through the communication circuit the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment within the preset detection period before a subsequent transmission period.
The UE according to claim 38, wherein the CCA of the subsequent transmission period has the same or more aggressive detection parameters than the CCA of the previous transmission period.
The UE according to claim 39, wherein the detection parameters comprise at least one of a size of the contention window and the preset detection period.
The UE according to claim 39, wherein the processor is configured to acquire through the communication circuit the detection parameters from a base station, or autonomously determine the detection parameters.
The UE according to claim 36, wherein the processor is configured to, when a number of the at least one frequency resource segment corresponding to the at least one sub-channel evaluated as non-clear during the preset detection period of the assigned transmission period is greater than a preset value, continue performing the CCA on the at least one sub-channel corresponding to the at least one frequency resource segment of the assigned frequency resource segment group within the assigned transmission period.
The UE according to claim 34, wherein the processor is further configured to acquire, from a control signal transmitted from a base station, information of the assigned frequency resource segments and assigned transmission period.
The UE according to claim 33-43, wherein the processor is configured to: perform, through the communication circuit, energy detection on the at least one sub-channel and thus acquire the signal energy on the at least one sub-channel； and if the signal energy is not higher than a preset threshold value, determine that the at least one sub-channel is idle.
A base station, comprising a processor and a transceiver connected to the processor； wherein

the processor is configured to:

receive through the transceiver a frequency resources segment indicator (FRSI) transmitted from at least one neighboring cell and used to indicate assignment information of frequency resources of an unlicensed spectrum in the at least one neighboring cell； and

assign the frequency resources of the unlicensed spectrum among a present cell based on relevant information provided by the FRSI from the at least one neighboring cell.
The base station according to claim 45, wherein the processor is further configured to inform through the transceiver periodically or aperiodically the FRSI of the present cell to the at least one neighboring cell.
The base station according to claim 45, wherein the assignment information comprises at least one of segmenting and grouping information of the frequency resources of the unlicensed spectrum； and

the processor is configured to at least segment or group the frequency resources of the unlicensed spectrum among the present cell based on the relevant information provided by the FRSI from the at least one neighboring cell to acquire frequency resource segments or frequency resource segment groups for the present cell.
The base station according to claim 47, wherein the processor is further configured to assign through the transceiver the frequency resource segments or frequency resource segment groups among at least one user equipment (UE) within the present cell, and ensure that the frequency resource segments or frequency resource segment groups assigned to the at least one UE within the present cell do not overlap with those assigned to at least one UE within each of the at least one neighboring cell.
The base station according to claim 47, wherein the processor is further configured to: acquire a listen-before-talk (LBT) failure rate indicator (LFRI) used to indicate a failure rate of LBT procedures corresponding to frequency resource segments or frequency resource segment groups； and at least re-assign the frequency resources among the present cell based on the relevant information provided by the LFRI, or adjust, through the transceiver, transmission power or detection parameters of user equipment within the present cell, based on the relevant information provided by the LFRI.
The base station according to claim 49, wherein the processor is further configured to inform through the transceiver periodically or aperiodically the LFRI of the present cell to the at least one neighboring cell.
The base station according to claim 49, wherein the processor is configured to perform at least one of the following operations:

at least re-segmenting or re-grouping the frequency resources within the present cell based on the relevant information provided by the LFRI； and

re-assigning through the transceiver the frequency resource segments or frequency resource segment groups to user equipment within the present cell based on the relevant information provided by the LFRI.