CN106455108B

CN106455108B - listen-before-talk method and device

Info

Publication number: CN106455108B
Application number: CN201510483745.2A
Authority: CN
Inventors: 王加庆; 潘学明; 徐伟杰; 司倩倩
Original assignee: China Academy of Telecommunications Technology CATT
Current assignee: China Academy of Telecommunications Technology CATT; Datang Mobile Communications Equipment Co Ltd
Priority date: 2015-08-07
Filing date: 2015-08-07
Publication date: 2019-12-13
Anticipated expiration: 2035-08-07
Also published as: CN106455108A; WO2017024915A1

Abstract

The invention discloses a method and a device for listening and speaking first, comprising the following steps: determining the frequency domain distance between carriers or between a carrier set and a carrier set; when the frequency domain distance is larger than a preset value, carrying out listen-before-talk operation on the carrier or the carrier set respectively; and when the frequency domain distance is smaller than a preset value, carrying out the operation of listening and speaking first on the carrier or the carrier set synchronously. The invention solves the problem that the prior art can not listen before talk when the unlicensed frequency band has multiple carriers or multiple carrier sets.

Description

listen-before-talk method and device

Technical Field

The present invention relates to the field of wireless communications technologies, and in particular, to a listen-before-talk method and an apparatus.

background

the unlicensed spectrum does not plan a specific application system, and can be shared by various wireless communication systems such as bluetooth and WiFi, and the various systems use shared unlicensed spectrum resources in a resource preemption manner. Therefore, coexistence between LTE-U (Unlicensed LTE, referred to as U-LTE or LTE-U for short; LTE: Long Term Evolution) deployed by different operators and wireless communication systems such as LTE-U and WiFi is a key point and a difficult point of research. 3GPP requires to ensure fair coexistence of LTE-U and WiFi and other wireless communication systems, and an unauthorized frequency band is used as an auxiliary carrier and is realized by the assistance of a main carrier of an authorized frequency band. LBT (listen-first Talk) is approved by almost all companies as a basic means for LTE-U contention access.

An 802.11 system adopts a channel Access mechanism called CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) mechanism, fig. 1 is a schematic diagram of a resource preemption mode of WiFi on an unlicensed spectrum, as shown in the figure, when a WiFi system preempts resources on the unlicensed spectrum, monitoring a channel first, when a channel idle time reaches DIFS (DCF Inter-Frame Space, DCF Frame Space; DCF distributed channel Access), determining that a current channel is an idle channel, and then each station of a channel waiting to be accessed enters a random backoff stage to avoid Collision of Multiple stations on the same resource. In addition, in order to ensure fairness, it is further specified that each station cannot occupy spectrum resources for a long time, and when a certain time or an upper limit of data transmission amount is reached, resources need to be released so that other WiFi or LTE systems can occupy the resources.

In order to provide a flexible and fair adaptive Channel access mechanism, europe requires LBT technology in unlicensed 5150-5350MHz and 5470-5725MHz bands, where LBT process is similar to CSMA/CA mechanism of WiFi, and each device performs CCA (Clear Channel Assessment) detection before using the Channel. The CCA determines whether a current channel has a signal transmitted by using energy detection, and then determines whether the channel is occupied. ETSI (european telecommunications Standards Institute) standard classifies unlicensed band devices into frame-based and load-based, respectively corresponding to two types of access mechanisms: FBE (Frame Based Equipment) and LBE (Load Based Equipment), fig. 2a is a schematic diagram of an ETSI FBE channel access mechanism, fig. 2B is a schematic diagram of an ETSI LBE option B channel access mechanism, as shown in fig. 2a and fig. 2B, the FBE and LBE access mechanisms are as follows:

the FBE accesses to execute CCA detection at a fixed frame structure position, accesses to a channel immediately as long as the channel has a CCA period (not less than 20us) and judges that the channel is empty, initiates a data transmission process, the occupation time of the channel transmission time is relatively fixed, the minimum 1ms and the maximum 10ms, the idle period is at least 5% of the occupation time of the channel, and the equipment executes new CCA detection to access to the channel again in the CCA time at the tail of the idle period. In the FBE mechanism, the channel occupation time plus idle period is a fixed value called frame period.

in an LBE channel access mechanism, the occupied time and the starting point of each transmission to a channel are both variable, extended CCA detection is carried out before the channel is acquired, firstly, a random factor N is generated according to the size q of a CW (contention window), the channel is accessed until the idle time of the channel reaches N times of the CCA time and the channel is idle, a data transmission process is initiated, and the maximum channel occupied time is 13 ms. ETSI LBE is divided into option a and option B options, where ETSI option B contention window is fixed and is the most basic form of LBE.

When the WiFi adopts a CSMA/CA access mechanism, a contention window index expansion mode is adopted, the minimum CW is set to be 24-1 slots, after the transmissions of two stations collide, the contention window is doubly expanded to 31 which is 25-1 in the next contention, and the maximum CW can be 1023. In order to achieve fair coexistence of LTE-U and WiFi, when LBT mechanism based on LBE is adopted, the current 3GPP has been studied and concluded that for downlink LBT, it should be modified based on ETSI LBE option B, it should adopt load-based LBT and contention window is exponentially increased or semi-statically configured, similar to DIFS interval of WiFi, LTE-U needs a defer similar to DIFS before starting ECCA (extended CCA, extended CCA detection) countdown every time. The above discussion is based on LBT on an unlicensed carrier of one LTE-U.

currently, 3GPP is currently under study to define two types of LBT for load-based transmission, namely LBT category 3 and LBT category 4. LBT category 3 uses a fixed contention window, e.g., LBEoption B belongs to LBT category 3; LBT category 4 is based on ETSI LBEoption B correction, adopts load-based LBT and the contention window is index-increasing or semi-static configuration; similar to the DIFS interval of WiFi, LBT category 4 needs a defer similar to DIFS before starting ECCA countdown every time.

The defects of the prior art are as follows: although the prior art has a scheme for performing LBT on an unlicensed carrier of an LTE-U, there is no technical scheme for performing LBT when there are multiple carriers in an unlicensed frequency band.

disclosure of Invention

the invention provides an LBT method and device, which are used for solving the problem that LBT cannot be carried out when an unlicensed frequency band has multiple carriers or multiple carrier sets.

the embodiment of the invention provides an LBT method, which comprises the following steps:

Determining the frequency domain distance between carriers or between a carrier set and a carrier set;

When the frequency domain distance is larger than a preset value, carrying out LBT operation on the carrier or the carrier set respectively;

And when the frequency domain distance is smaller than a preset value, carrying out LBT operation on the carrier or the carrier set synchronously.

preferably, the LBT operation is performed on a carrier or a set of carriers, respectively, and includes: LBT operations for uplink or downlink transmission are performed on different carriers or carrier sets, respectively.

preferably, when a carrier or a carrier set is located in different frequency bands, performing LBT operation on the carrier or the carrier set, respectively, includes: LBT operation for uplink or downlink transmission is respectively carried out on carriers or carrier sets on different frequency bands;

when a carrier or a carrier set is located in the same frequency band, performing LBT operations on the carrier or the carrier set, respectively, including: and respectively carrying out LBT operation for uplink or downlink transmission on the carriers or the carrier sets with the distance between the carriers larger than a preset value.

Preferably, further comprising:

When the carrier sets are respectively positioned at different frequency bands, synchronously and respectively carrying out LBT operation for uplink or downlink transmission on the carrier sets on the different frequency bands;

and when the carrier sets are positioned in the same frequency band, synchronously and respectively carrying out LBT operation for uplink or downlink transmission on the carrier sets.

Preferably, the performing LBT operations synchronously on a carrier or a set of carriers includes:

determining a main carrier and a slave carrier in each carrier;

detecting one access mode on the main carrier and detecting the other access mode on the auxiliary carrier;

according to the detection result on the main carrier, when a channel is accessed on the main carrier, if the detection result on the auxiliary carrier is idle, the channel is accessed on the main carrier and the auxiliary carrier, and if the detection result on the auxiliary carrier is busy, the channel is abandoned on the main carrier and the auxiliary carrier;

or the like, or, alternatively,

Determining a main carrier set and a slave carrier set in each carrier set;

detecting one access mode on the main carrier set and detecting the other access mode on the auxiliary carrier set;

And according to the detection result on the main carrier set, when the channel is accessed on the main carrier set, if the detection result on the auxiliary carrier set is idle, the channel is accessed on the main carrier set and the auxiliary carrier set, and if the detection result on the auxiliary carrier set is busy, the channel is abandoned on the main carrier set and the auxiliary carrier set.

preferably, the detection performed on the primary carrier or set of primary carriers is ECCA; and/or the detection on the slave carrier or the slave carrier set is ICCA.

preferably, the primary carrier or the set of primary carriers is determined by one or a combination of the following:

determining a main carrier or a main carrier set according to the busy/idle information of the feedback channel, determining the main carrier or the main carrier set according to the statistical information of the busy degree of the feedback channel, determining the main carrier or the main carrier set according to the real-time detection information of the feedback channel, and randomly selecting the main carrier or the main carrier set.

an embodiment of the present invention provides an LBT device, including:

the frequency domain distance determining module is used for determining the frequency domain distance between carriers or between a carrier set and a carrier set;

The LBT operation module is used for respectively carrying out LBT operation on the carrier or the carrier set when the frequency domain distance is larger than a preset value; and when the frequency domain distance is smaller than a preset value, carrying out LBT operation on the carrier or the carrier set synchronously.

preferably, the LBT operation module is further configured to perform LBT operations for uplink or downlink transmission on different carriers or carrier sets when performing LBT operations on the carriers or carrier sets, respectively.

preferably, the LBT operation module is further configured to perform LBT operations for uplink or downlink transmission on carriers or carrier sets on different frequency bands when the carriers or carrier sets are located in different frequency bands respectively and perform LBT operations on carriers or carrier sets on different frequency bands respectively; and when the carriers or the carrier sets are positioned in the same frequency band and the LBT operation is respectively carried out on the carriers or the carrier sets, carrying out the LBT operation for uplink or downlink transmission on the carriers or the carrier sets with the distance between the carriers larger than a preset value.

Preferably, the LBT operation module is further configured to perform LBT operations for uplink or downlink transmission synchronously and respectively on carrier sets on different frequency bands when the carrier sets are located in different frequency bands respectively; and when the carrier sets are positioned in the same frequency band, synchronously and respectively carrying out LBT operation for uplink or downlink transmission on the carrier sets.

preferably, the LBT operation module is further configured to, when performing LBT operation synchronously on a carrier or a set of carriers:

determining a main carrier and a slave carrier in each carrier;

or the like, or, alternatively,

determining a main carrier set and a slave carrier set in each carrier set;

Preferably, the LBT operation module is further configured to perform ECCA on the primary carrier or the set of primary carriers; and/or ICCA over a slave carrier or a set of slave carriers.

preferably, the LBT operation module is further configured to determine the primary carrier or the set of primary carriers by one or a combination of the following:

The invention has the following beneficial effects:

in the technical solution provided in the embodiment of the present invention, how to perform LBT operation is determined according to the frequency domain distance between each carrier or the carrier set, so that the problem that LBT cannot be performed when there is a multi-carrier or a multi-carrier set in an unlicensed frequency band in the prior art is solved.

drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

Fig. 1 is a schematic diagram illustrating a resource preemption method by WiFi on an unlicensed spectrum in the background art;

FIG. 2a is a diagram of an ETSI FBE channel access mechanism in the background art;

FIG. 2B is a diagram illustrating the access mechanism of ETSI LBE option B channel in the background art;

FIG. 3 is a flow chart illustrating an implementation of an LBT method in an embodiment of the present invention;

fig. 4 is a diagram illustrating multi-carrier synchronization LBT according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of an LBT device in accordance with an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a communication device in an embodiment of the present invention.

Detailed Description

the following describes embodiments of the present invention with reference to the drawings.

the inventor notices in the course of the invention that, although the prior art has a scheme of performing LBT on an unlicensed carrier based on one LTE-U, there is no technical scheme of performing LBT when there are multiple carriers in an unlicensed frequency band. However, multiple idle carriers may exist in the unlicensed frequency band in the LTE-U, and the multiple carriers may be adjacent or discontinuous, so that a larger bandwidth may be obtained by reusing the LTE carrier aggregation.

similar to WiFi, currently, each carrier of LTE-U is 20M, adjacent carriers inevitably have RF (Radio Frequency) leakage, and if a carrier is transmitting a signal, even if the adjacent carrier is in an idle state, due to adjacent channel interference, the LBT energy detection result is busy, so each carrier needs to perform LBT and synchronous transmission synchronously.

based on this, the embodiment of the present invention provides a scheme for a base station or a terminal to access multiple carriers in an unlicensed frequency band. Mainly comprises the following steps: when the frequency domain distance between the carriers or the carrier sets is larger than a preset value, the LBT performed by the base station or the terminal on the carriers or the carrier sets can be mutually independent; when the frequency-domain distance between the carriers or the carrier sets is smaller than a preset value, the base station or the terminal synchronously performs LBT operation on the carriers or the carrier sets, which is described below.

fig. 3 is a schematic flow chart of an LBT method, as shown in the figure, which may include:

step 301, determining a frequency domain distance between carriers or between a carrier set and a carrier set;

step 302, when the frequency domain distance is greater than a preset value, performing LBT operation on a carrier or a carrier set respectively; and when the frequency domain distance is smaller than a preset value, carrying out LBT operation on the carrier or the carrier set synchronously.

In implementation, when determining the preset value of the frequency domain distance, the preset value may be determined by whether the interference between adjacent carriers is lower than a certain threshold, for example, currently, generally-6 db, where the specific threshold needs to be determined according to actual needs and device conditions, and the purpose of determining the frequency domain distance is to determine the degree of interference, so that a person skilled in the art can easily know how to determine the preset value according to actual conditions.

In implementation, a base station or a terminal first determines a frequency domain distance between carriers or carrier sets that need LBT, the carriers or carrier sets whose frequency domain distance is greater than a preset distance may perform independent LBT operations respectively, and the carriers or carrier sets whose frequency domain distance is less than the preset distance perform LBT operations synchronously.

for a better understanding, the following description is given by way of example.

Example 1

In this example, performing LBT operations on a carrier or a set of carriers, respectively, may include: LBT operations for uplink or downlink transmission are performed on different carriers or carrier sets, respectively.

specifically, when distance measurement is performed on a carrier or a carrier set, if two carriers or two carrier sets are located in two bands (frequency bands), particularly two non-adjacent bands, for example, one is located in a 2.4G frequency band and one is located in a 5G frequency band, and a distance between the carriers or the carrier sets is far greater than a preset value of a frequency domain distance, carrier sets on different bands are used for different transmissions, for example, DL (Downlink ) and UL (Uplink, Uplink) transmissions are independently performed on different bands, LBTs on the two bands are independent from each other, that is: performing LBT operations on a carrier or a set of carriers when the carrier or the set of carriers are located in different frequency bands, respectively, may include: LBT operations for uplink or downlink transmission are performed on carriers or carrier sets on different frequency bands, respectively. In a specific implementation, an LBT primary carrier may be configured on each band, and each band independently performs an LBT operation according to the configured LBT primary carrier.

if multiple carriers or carrier sets are located in the same band, different carriers or carrier sets may be needed for DL and UL transmission, and at this time, it is determined whether the distance between the carriers or carrier sets can be independently subjected to LBT operation, and the frequency domain distance between two carriers or the closest two of the two carrier sets may be used for measurement, although other manners may also be adopted. A plurality of carrier sets that can be used for independent LBT may be determined according to the distance between the measurement carriers and the preset frequency domain distance, and the base station or the terminal may perform independent LBT on the carrier sets respectively for DL or UL transmission, for example, one DL LBT primary carrier may be configured for DL transmission within one band, and one UL LBT primary carrier may be configured for UL transmission for DL and UL independent LBT, respectively. That is, when a carrier or a carrier set is located in the same frequency band, performing LBT operation on the carrier or the carrier set, respectively, may include: and respectively carrying out LBT operation for uplink or downlink transmission on the carriers or the carrier sets with the distance between the carriers larger than a preset value.

in a specific implementation, it is not excluded that the base station or the terminal synchronously performs LBT aggregation on the carrier sets satisfying that the frequency domain distance is greater than the preset value to form a larger bandwidth, for example, on two bands, each band performs LBT according to its own LBT primary carrier synchronization, the two LBT primary carriers also keep synchronization, and are aggregated to form a larger bandwidth on each band, if the two band-aggregated carrier synchronization access channels are, the two band-aggregated carrier synchronization access channels are aggregated to form a larger bandwidth across bands, and if the two band-aggregated carriers cannot keep the synchronization access channels, the two band-aggregated carriers are respectively and independently transmitted. That is, when the carrier sets are located in different frequency bands, LBT operations for uplink or downlink transmission are synchronously performed on the carrier sets on the different frequency bands, respectively.

in implementation, when the carrier sets are located in the same frequency band, LBT operations for uplink or downlink transmission may also be performed synchronously on the carrier sets. Specifically, LBT can be performed independently when the distance between the carrier sets is greater than a preset value, and if the carrier sets at both ends meet the condition of performing LBT independently within one band, a synchronous LBT mode can also be adopted.

Example 2

In this example, when the frequency-domain distance between carriers or carrier sets is smaller than a preset value, the base station or the terminal may perform LBT in synchronization with the carriers or carrier sets that satisfy the condition. That is, LBT operations are performed synchronously on a carrier or a set of carriers, including:

determining a main carrier and a slave carrier in each carrier;

or the like, or, alternatively,

determining a main carrier set and a slave carrier set in each carrier set;

In implementation, when determining the primary carrier and the secondary carrier, the master-slave relationship is determined from each carrier or a carrier set, and not the primary carrier and the secondary carrier in the LTE-U, because generally, those skilled in the art think that the primary carrier in the LTE-U refers to an LTE carrier in a licensed frequency band, and all carriers in an unlicensed frequency band are secondary carriers.

in a specific implementation, the scheme for performing LBT synchronously by the base station or the terminal may be as follows:

A network, a base station or a terminal configures a primary carrier for performing LBT for a carrier set which needs to perform LBT synchronously in an unlicensed frequency band, and determines the primary carrier or the primary carrier set by one or a combination of the following modes: determining a main carrier or a main carrier set according to the busy/idle information of the feedback channel, determining the main carrier or the main carrier set according to the statistical information of the busy degree of the feedback channel, determining the main carrier or the main carrier set according to the real-time detection information of the feedback channel, and randomly selecting the main carrier or the main carrier set.

A base station or a terminal generates a time slot needing random backoff or the number of idle CCA time slots needing detection on an LBT primary carrier according to a fixed contention window, a dynamically expanded contention window, or a semi-statically configured contention window on the LBT primary carrier, performs ECCA detection on the LBT primary carrier, a non-LBT primary carrier does not perform random backoff before accessing a channel of the LBT primary carrier, does not perform ECCA detection, performs only ICCA (Initial CCA) detection, if the non-LBT primary carrier is in the LBT primary carrier access channel, the ICCA detection result is idle, the non-LBT primary carrier and the LBT primary carrier access the channel together, if the ICCA result is busy, abandons the access channel this time, and the time slot length required for the ICCA detection is configurable.

In the implementation, the access method of the LBT primary carrier and the LBT secondary carrier in the above embodiment is only an example, but does not exclude the use of other combinations of access methods, for example, the access method of LBT category 4 is used on the LBT primary carrier, and the access method of LBT category 3 is used on the LBT secondary carrier.

In the implementation, there is one primary carrier configured in the foregoing embodiment for performing LBT, but the scheme of the present application is not only applicable to limit the LBT primary carrier in the same band to one, but also may be multiple in the implementation, at least DL and UL may respectively use different LBT primary carriers, and meanwhile, downlink may also be configured as multiple downlink LBT primary carriers according to circumstances and needs, and in the implementation, the manner in the embodiment may be used when the distance exceeds the frequency domain distance.

multiple carriers need to perform LBT synchronously, the main purpose is to increase aggregation bandwidth and avoid adjacent or similar channel RF leakage interference LBT, fig. 4 is a schematic diagram of multi-carrier synchronization LBT, as shown in the figure, 20M LBT carriers randomly generate backoff according to a contention window, start an ECCA detection process, access a channel once LBT succeeds, while other non-LBT LTE-U carriers only perform ICCA detection, and determine whether to access the channel according to an ICCA detection result. Fig. 4 is only an example of multi-carrier synchronization LBT and does not exclude other multi-carrier synchronization LBTs. In fig. 4, the LBT primary carrier uses load-based LBT, and does not exclude frame-based LBT or other LBT schemes with random backoff as a fixed value.

Based on the same inventive concept, the embodiment of the present invention further provides an LBT device, and as the principle of the device for solving the problem is similar to that of an LBT method, the implementation of the device may refer to the implementation of the method, and repeated details are not repeated.

Fig. 5 is a schematic structural diagram of an LBT device, as shown, the LBT device may include:

a frequency domain distance determining module 501, configured to determine a frequency domain distance between carriers, or between a carrier set and a carrier set;

An LBT operation module 502, configured to perform LBT operations on carriers or carrier sets when the frequency-domain distance is greater than a preset value; and when the frequency domain distance is smaller than a preset value, carrying out LBT operation on the carrier or the carrier set synchronously.

in an implementation, the LBT operation module may be further configured to perform LBT operations for uplink or downlink transmission on different carriers or carrier sets when performing the LBT operations on the carriers or carrier sets, respectively.

In an implementation, the LBT operation module may be further configured to perform LBT operations on carriers or carrier sets in different frequency bands, respectively, and perform LBT operations for uplink or downlink transmission on carriers or carrier sets in different frequency bands when performing LBT operations on the carriers or carrier sets, respectively; and when the carriers or the carrier sets are positioned in the same frequency band and the LBT operation is respectively carried out on the carriers or the carrier sets, carrying out the LBT operation for uplink or downlink transmission on the carriers or the carrier sets with the distance between the carriers larger than a preset value.

In implementation, the LBT operation module may further be configured to perform LBT operations for uplink or downlink transmission synchronously and respectively on carrier sets on different frequency bands when the carrier sets are located in different frequency bands respectively; and when the carrier sets are positioned in the same frequency band, synchronously and respectively carrying out LBT operation for uplink or downlink transmission on the carrier sets.

In an implementation, the LBT operation module may be further configured to, when performing LBT operation synchronously on a carrier or a set of carriers:

determining a main carrier and a slave carrier in each carrier;

Or the like, or, alternatively,

determining a main carrier set and a slave carrier set in each carrier set;

in an implementation, the LBT operation module may be further configured to perform ECCA on the primary carrier or the set of primary carriers; and/or ICCA over a slave carrier or a set of slave carriers.

In an implementation, the LBT operation module may be further configured to determine the primary carrier or the set of primary carriers by one or a combination of the following manners:

For convenience of description, each part of the above-described apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware in practicing the invention.

when the technical scheme provided by the embodiment of the invention is implemented, the implementation can be carried out as follows.

fig. 6 is a schematic structural diagram of a communication device, as shown in the figure, the communication device may include:

The processor 600, which is used to read the program in the memory 620, executes the following processes:

A transceiver 610 for transmitting data under the control of the processor 600, performing the following processes:

In an implementation, the LBT operation is performed on a carrier or a set of carriers, respectively, and includes: LBT operations for uplink or downlink transmission are performed on different carriers or carrier sets, respectively.

In an implementation, when a carrier or a carrier set is located in different frequency bands, respectively, performing LBT operations on the carrier or the carrier set, respectively, includes: LBT operation for uplink or downlink transmission is respectively carried out on carriers or carrier sets on different frequency bands;

In an implementation, the method further comprises the following steps:

in an implementation, the synchronizing LBT operations on a carrier or a set of carriers includes:

Determining a main carrier and a slave carrier in each carrier;

Or the like, or, alternatively,

determining a main carrier set and a slave carrier set in each carrier set;

In implementation, the detection performed on the primary carrier or set of primary carriers evaluates ECCA for an extended clear channel; and/or evaluating ICCA for an initial clear channel upon detection from a carrier or from a set of carriers.

in an implementation, the primary carrier or the set of primary carriers is determined by one or a combination of the following ways:

Where in fig. 6, the bus architecture may include any number of interconnected buses and bridges, with various circuits being linked together, particularly one or more processors represented by processor 600 and memory represented by memory 620. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 610 may be a number of elements including a transmitter and a transceiver providing a means for communicating with various other apparatus over a transmission medium. The processor 600 is responsible for managing the bus architecture and general processing, and the memory 620 may store data used by the processor 600 in performing operations.

In summary, in the technical solution provided in the embodiment of the present invention, for the case that the LTE-U performs LBT in the unlicensed frequency band and the adjacent carriers need to perform synchronous LBT due to RF leakage, a scheme of multi-carrier LBT is proposed, where synchronous LBT is performed on the adjacent carriers within the same band, and LBT is performed separately on the carrier sets with far frequency domain distances, such as two bands.

With the continuous increase of mobile data traffic, spectrum resources are more and more tense, and network deployment and service transmission performed by using only authorized spectrum resources may not meet traffic demands, so that the LTE system may consider deploying transmission on unauthorized spectrum resources to improve user experience and extend coverage. But at present, no clear method exists how the LTE system works on the unlicensed spectrum resources. The technical scheme provided by the embodiment of the invention provides a scheme for carrying out LBT on a plurality of carriers on an unlicensed frequency spectrum by an LTE system. The scheme can effectively ensure that the aggregation of a plurality of carriers can be realized by a simple mode, so that the carriers in different bands can independently carry out LBT and are respectively used for DL and UL transmission.

as will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

these computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

these computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A listen-before-talk, LBT, method comprising:

when the frequency domain distance is smaller than the preset value, LBT operation is synchronously carried out on the carrier or the carrier set,

Wherein the performing LBT operations synchronously on a carrier or a set of carriers comprises:

Determining a main carrier and a slave carrier in each carrier;

or the like, or, alternatively,

determining a main carrier set and a slave carrier set in each carrier set;

2. The method of claim 1, wherein performing LBT operations on a carrier or a set of carriers, respectively, comprises: LBT operations for uplink or downlink transmission are performed on different carriers or carrier sets, respectively.

3. the method of claim 2,

when a carrier or a carrier set is located in different frequency bands, respectively, performing LBT operations on the carrier or the carrier set, respectively, including: LBT operation for uplink or downlink transmission is respectively carried out on carriers or carrier sets on different frequency bands;

4. the method of claim 3, further comprising:

5. the method of claim 1, wherein the detection made on a primary carrier or a set of primary carriers is an Extended Clear Channel Assessment (ECCA); and/or evaluating ICCA for an initial clear channel upon detection from a carrier or from a set of carriers.

6. The method of claim 1, wherein a primary carrier or set of primary carriers is determined by one or a combination of:

7. an LBT device, comprising:

the LBT operation module is used for respectively carrying out LBT operation on the carrier or the carrier set when the frequency domain distance is larger than a preset value; when the frequency domain distance is smaller than the preset value, LBT operation is synchronously carried out on the carrier or the carrier set,

wherein the LBT operation module is further configured to, when performing LBT operation synchronously on a carrier or a set of carriers:

determining a main carrier and a slave carrier in each carrier;

or the like, or, alternatively,

determining a main carrier set and a slave carrier set in each carrier set;

8. The apparatus of claim 7, wherein the LBT operation module is further for performing LBT operations for uplink or downlink transmissions on different carriers or sets of carriers, respectively, when the LBT operations are performed on the carriers or sets of carriers, respectively.

9. The apparatus of claim 8, wherein the LBT operation module is further configured to perform LBT operations for uplink or downlink transmissions on carriers or sets of carriers on different frequency bands, respectively, when the LBT operations are performed on the carriers or sets of carriers, respectively, located in different frequency bands; and when the carriers or the carrier sets are positioned in the same frequency band and the LBT operation is respectively carried out on the carriers or the carrier sets, carrying out the LBT operation for uplink or downlink transmission on the carriers or the carrier sets with the distance between the carriers larger than a preset value.

10. The apparatus of claim 9, wherein the LBT operation module is further configured to perform LBT operations for uplink or downlink transmissions respectively on the sets of carriers on different frequency bands synchronously when the sets of carriers are located in different frequency bands respectively; and when the carrier sets are positioned in the same frequency band, synchronously and respectively carrying out LBT operation for uplink or downlink transmission on the carrier sets.

11. the apparatus of claim 7, wherein LBT operation module is further for ECCA on a primary carrier or a set of primary carriers; and/or ICCA over a slave carrier or a set of slave carriers.

12. the apparatus of claim 7, wherein the LBT operation module is further for determining a primary carrier or a set of primary carriers by one or a combination of: