WO2017166198A1

WO2017166198A1 - Method for determining channel state and communication device

Info

Publication number: WO2017166198A1
Application number: PCT/CN2016/078106
Authority: WO
Inventors: Gan Wen; Ge HUANG; Jinsong Yang
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2016-03-31
Filing date: 2016-03-31
Publication date: 2017-10-05

Abstract

Embodiments of the present disclosure relate to a method for determining a channel state and a communication device. In example embodiments a first subinterval state of a channel is predicted. The first subinterval state indicates whether the channel is idle in a first subinterval of a target time interval in which the communication device operates in a transmitting mode. Then, an interval state of the channel is determined at least in part based on the first subinterval state of the channel. The interval state indicates whether the channel is idle in the target time interval. Such determination of the channel state may improve efficiency of channel assessment.

Description

METHOD FOR DETERMINING CHANNEL STATE AND COMMUNICATION DEVICE

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication， and in particular， to a method for determining a channel state and a communication device thereof.

BACKGROUND

The License Assisted Access (LAA) technology allows un-licensed bands to be shared between networks and therefore to supplement licensed bands so as to meet an increasing demand for wireless broadband data. In order to achieve fair access to the un-licensed band by the individual networks and avoid interferences between the networks， a base station (BS) needs to listen to a channel to determine whether the channel is idle before transmitting data in the channel. Such listening is also known as Clear Channel Assessment (CCA) which is used to evaluate a channel state. In a CCA procedure， the BS measures a power level of the channel. If the measured power level is below a threshold level， the BS determines that the channel is idle. The CCA procedure is conventionally performed when the BS operates in a receiving mode because a transmitting and receiving circuits within the BS typically cannot be active at the same time.

In order to achieve high data rate and system throughput， the BS in a third Generation Partnership (3GPP) Long Term Evolution (LTE) network may operate on multiple carriers. For such a BS， the CCA procedures for the channels on the multiple carriers are performed in aligned timing. For example， the CCA procedures on the carriers may be started in alignment with a boundary of a LTE sub-frame when the BS is in the receiving mode. Such a CCA procedure will degrade fairness of access to the various carriers. As a result， the efficiency of access to the network may be reduced.

SUMMARY

In general， example embodiments of the present disclosure provide a method for determining a channel state and a communication device.

In a first aspect， a method implemented by a communication device is provided. According to the method， a first subinterval state of a channel is predicted， The first subinterval state indicates whether the channel is idle in a first subinterval of a target time interval in which the communication device operates in a transmitting mode. Then， an interval state of the channel is determined at least in part based on the first subinterval state of the channel. The interval state indicates whether the channel is idle in the target time interval. A computer program product for carry out this method is also provided.

In some embodiments， predicting the first subinterval state comprises： determining a probability that the channel is idle in a reference time interval prior to the first time-interval， the communication device operating in a receiving mode in the reference time interval； and predicting the first subinterval state based on the determined probability.

In some embodiments， determining the probability comprises： detecting a plurality of second subinterval states of the channel， the second subinterval states indicating whether the channel is idle in a plurality of second subintervals of the reference time interval； and determining the probability based on the plurality of second subinterval states.

In some embodiments， the reference time interval is partially overlapped with the target time interval.

In some embodiments， determining the interval state comprises： obtaining a plurality of third subinterval states of the channel， the plurality of third subinterval states indicating whether the channel is idle in a plurality of third subintervals of the target time interval； determining a count of idle subintervals from the first subinterval and the plurality of third subintervals， the channel being idle in the idle subintervals； and in response to the count of idle subintervals exceeding a threshold， determining that the channel is idle in the target time interval.

In a second aspect， a communication device is provided. The communication device comprises： a predicting unit configured to predict a first subinterval state of a channel， the first subinterval state indicating whether the channel is idle in a first subinterval of a target time interval， the communication device operating in a transmitting mode in the first subinterval； and a state determining unit configured to determine an interval state of the channel at least in part based on the first subinterval state of the channel， the interval state indicating whether the channel is idle in the target time interval.

In a third aspect， a communication device is provided. The communication device comprises a processor configured to perform the method according to the first aspect.

In a fourth aspect， a communication device is provided. The communication device comprises means operative to perform the method according to the first aspect.

Through the following description， it would be appreciated that according to embodiments of the present disclosure， the communication device may predict a channel state in the transmitting mode. In this way， efficiency of the channel assessment may be improved.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure， nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings， the above and other objects， features and advantages of the present disclosure will become more apparent， wherein：

Fig. 1 is a block diagram of an environment in which embodiments of the present disclosure can be implemented；

Fig. 2 is a flowchart of a method for determining a channel state in accordance with some embodiments of the present disclosure；

Figs. 3a to 3d are example timing sequences of the reference time interval and the first subinterval according to some embodiments of the present disclosure；

Fig. 4 is a flowchart of an example method for determining a channel state according to some other embodiments of the present disclosure；

Fig. 5 is a flowchart of an example method for determining a channel state in the CCA procedure in accordance with some embodiments of the present disclosure； and

Fig. 6 is a block diagram of a communication device in accordance with some embodiments of the present disclosure；

Fig. 7 is a simplified block diagram of a communication device that is suitable for implementing embodiments of the present disclosure.

Throughout the drawings， the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure， without suggesting any limitations as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones describe below.

As used herein， the term “terminal device” or “terminal” refers to any device having wireless communication capabilities， including， but not limited to， mobile phones， cellular phones， smart phones， personal digital assistants (PDAs) ， portable computers， image capture devices such as digital cameras， gaming devices， music storage and playback appliances， any portable units or terminals that have wireless communication capabilities， or Internet appliances enabling wireless Internet access and browsing and the like.

In addition， in the context of the present disclosure， the terms “terminal device” or “user equipment” (UE) can be used interchangeably for ease of discussion. Examples of a UE in a telecommunication system include， but are not limited to， a Mobile Terminal (MT) ， a Subscriber Station (SS) ， a Portable Subscriber Station (PSS) ， a Mobile Station (MS) ， or an Access Terminal (AT) .

As used herein， the term “base station” (BS) refers to a device which is capable of providing or hosting a cell to which one or more terminal devices can access. Examples of a BS include， but are not limited to， a Node B (NodeB or NB) ， an Evolved NodeB (eNodeB or eNB) ， a Remote Radio Unit (RRU) ， a radio header (RH) ， a remote radio head (RRH) ， a relay， a low power node such as a femto， a pico， and the like. The term “base station” (BS) refers to a device which is capable of providing or hosting an area to which one or more terminal devices can access. An access node may be implemented， for example， as a wireless router and the like.

As used herein， the term “communication device” refers to any device that needs to detect an idle channel before transmitting data. Examples of the communication device include， but are not limited to， a base station and a terminal device.

As used herein， the term “includes” and its variants are to be read as open terms that mean “includes， but is not limited to. ” The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” Other definitions， explicit and implicit， may be included below.

In conventional CCA procedures， as described above， if the BS operates on multiple carriers， the CCA procedures on the carriers are performed in the aligned timing. If an idle channel is detected on one carrier， the transmission will be initiated in the idle channel on the carrier， and the CCA procedures on other carriers have to be terminated. Such a CCA procedure will degrade the fairness of access to the various carriers and the efficiency of access to the network.

In order to solve the above and other potential problems， embodiments of the present disclosure provides a method for determining a channel state by a communication device. According to embodiments of the present disclosure， during a period when the communication device operates in the transmitting mode， a channel state is predicted. Then， the channel state in a longer time period is determined based on the predicted channel state. In this way， even if the communication device is transmitting data， the determination of the channel state may not be terminated.

Fig. 1 shows an example environment 100 in which embodiments of the present disclosure can be implemented. The environment 100， which is a part of a communication network， includes one or more communication devices 110. In this example， the communication device 110 is a BS. It is to be understood that the environment 100 may also comprise other implementations of a communication device 110. For example， the environment 100 may also comprise one or more terminal devices. It is also to be understood that although two communication devices 110 are shown， this is only for the purpose of illustration without suggesting any limitations as to the scope of the present disclosure. The environment 100 may include any suitable number of the communication devices 110.

The communications performed by the communication device 110 may conform to any suitable standards including， but not limited to， LTE-Advanced (LTE-A) ， LTE， Wideband Code Division Multiple Access (WCDMA) ， Code Division Multiple Access (CDMA) and Global System for Mobile Communications (GSM) and the like. Furthermore， the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include， but are not limited to， the first generation (1G) ， the second generation (2G) ， 2.5G， 2.75G， the third generation (3G) ， the fourth generation (4G) ， 4.5G， the future fifth generation (5G) communication protocols.

The communication device 110 may simultaneously operate on one or more carriers C0， C1， and C2. Although three carriers are shown in Fig. 1， this is only for illustration without suggesting any limitations as to the scope of the present disclosure. The communication device 110 may operate on any suitable number of carriers. In particular， in some embodiments， the communication device 110 may operate on only one carrier， which will be described in the following paragraphs.

Before transmission， the communication device 110 operates in the receiving mode while performing the channel detection on the carriers C0， C1， and C2， for example， by the CCA procedure. If an idle channel is detected on one carrier such as the carrier C0， the communication device 110 transits to the transmitting mode and initiates transmission in the detected idle channel. According to embodiments of the present disclosure， in a subinterval 102 of a target time interval 104 in the transmitting mode， the communication device 110 predicts a subinterval state of a further channel， for example， on the carrier C1 orC2. The subinterval state indicates whether the further channel is idle in the subinterval 102. Then， the communication device 110 determines the interval state of the further channel in the target time interval 104 based on the predicted state in the subinterval. The interval state indicates whether the further channel is idle in the target time interval 104.

In the context of the present disclosure， the target time interval 104 refers to any suitable time period when a state of a channel needs to be determined， and the subinterval 102 refers to any suitable time period within the target time interval 104 when the communication device 110 operates in the transmitting mode. For the sake of discussion， the subinterval 102 will be referred to as a first subinterval 102， and the state of the channel in the first subinterval 102 will be referred to as a first subinterval state. Detailed implementations of the target interval and the first subinterval will be discussed in the following paragraphs.

It is to be understood although the channel to be determined and the transmission channel are shown as two channels on different carriers， this is only for the purpose of illustration， without suggesting any limitations as to the scope of the present disclosure. In some embodiments， the channel to be determined may be the transmission channel as will be described in the following paragraphs. As used herein， the term “transmission channel” refers to a channel on which the communication device 110 performs the transmission.

Fig. 2 shows a flowchart of an example method 200 for determining a channel state in accordance with some embodiments of the present disclosure. The method 200 can be implemented by the communication device 110.

In block 202， when the communication device 110 operates in the transmitting mode in a first subinterval 102 of a target time interval 104， the communication device 110 predicts a first subinterval state of a channel. The first subinterval state indicates whether the channel is idle in the first subinterval 102.

The target time interval 104 and the first subinterval 102 may have any suitable time length. In some embodiments， the target time interval 104 may be a channel sensing interval of the CCA procedure in a LTE system. The channel sensing interval may be pre-defined by the system as one subframe， for example. Accordingly， the first subinterval 102 may be the time period for which the communication device 110 operates in the transmitting mode， as shown in Fig. 1.

Additionally or alternatively， in some embodiments， the target time interval 104 may be evenly divided into multiple subintervals. For example， in the case that the target time interval 104 is predefined as one subframe in the LTE system， one of the multiple subintervals may be specified as one time slot. In this situation， the first subinterval 102 may be one of the subintervals. Accordingly， the time period for which the communication device 110 operates in the transmitting mode may include a plurality of subintervals containing the first subinterval 102. In these embodiments， the channel state may be predicted in the time period of the transmitting mode as will be discussed in the following paragraphs.

As described above， in some embodiments， the predicted channel and the transmission channel may be different. For example， still with reference to Fig. 1， after the communication device 110 detects an idle channel on the carrier C0 and initiates transmission in the detected idle channel， the communication device 110 predicts the first subinterval state of the channel on the carrier C1 or C2.

Alternatively， in other embodiments， the predicted channel may be the transmission channel. For example， during the CCA procedure for one channel in the target time interval 104， the communication device 110 such as the BS may need to transmit some control packets to a further communication device， such as the terminal device， in the first subinterval 102 of the target time interval 104. Conventionally， in this scenario， the communication device 110 transits to the transmitting mode and terminates the CCA procedure. After completion of the transmission， the communication device 110 restarts the CCA for the channel. However， according to embodiments of the present disclosure， the communication device 110 in the transmitting mode predicts the first subinterval state of the channel in the first subinterval 102. Thus， upon the transition from the transmitting mode to the receiving mode， the communicate device 110 may resume the CCA procedure based on the predicted channel state. Compared with the conventional termination of the CCA procedure， the predication of the first subinterval state may improve the efficiency of the channel assessment.

Any suitable prediction method may be used by the communication device 110. In some embodiments， the communication device 110 may predict the first subinterval state based on historically statistic information on the channel state. For example， the communication device 110 may determine a probability that the channel is idle in a reference time interval prior to the first time-interval and then perform the prediction based on the probability. The reference time interval 302 may be any suitable time period prior to the first subinterval 102. Figs. 3a to 3d show example timing sequences of the reference time interval and the first subinterval according to some embodiments of the present disclosure.

In particular， Fig. 3a shows that the reference time interval 302 is prior to the target time interval 104 and separated from the beginning of the target interval 104 by a specific period. In the example of Fig. 3b， the reference time interval 302 is immediately prior to the target time interval 104. In the example of Fig. 3c， the reference time interval 302 is separated from the beginning of the first subinterval 102 by a specific period and partially overlapped with the target time interval 104. Fig. 3d shows another possible situation where the reference time interval 302 is immediately prior to the first subinterval 102 and partially overlapped with the target time interval 104. For the sake of discussion， the prediction of the first subinterval state in associated with the reference time interval will be discussed below with reference to Figs. 3a to 3d.

In some embodiments， the reference time interval 302 may be a time period when the communication device 110 operates in the receiving mode. Accordingly， in the reference time interval 302， the communication device 110 may determine the probability by directly detecting the channel state， for example， through power measurements. In this way， accuracy of the following predication of the first subinterval state may be improved since the probability as the basis of the prediction is obtained from actual measures. It is to be understood that the reference time interval 302 may also include a further time period for which the communication device 110 operates in transmitting mode. It is also to be understood that the channel state in such a time period may also be obtained by the prediction method as described in the context of the present disclosure.

Additionally， in order to further improve the accuracy of the following prediction of the first subinterval state， in some embodiments， the reference time interval 302 may be partially overlapped with the target time interval 104 as shown in Figs. 3c and 3d. In particular， as shown in Fig. 3d， the reference time interval 302 may be selected to be a time interval that is immediately prior to the first subinterval 102. In this way， the determined probability may be more meaningful in statistics and therefore have more reference values for the following prediction of the first subinterval state. In some embodiments， the reference time interval 302 may have a time length exceeding a threshold interval such that the accuracy of the following prediction of the first subinterval state may be further improved.

Alternatively or additionally， in some embodiments， as shown in Fig. 3d， the reference time interval 302 may include one or more subintervals 304. For the sake of discussion， the subinterval 304 within the reference time interval will be referred to as a second subinterval 304. The second subinterval 304 may have any suitable time length. As described above， in some embodiments， the first subinterval 102 may be one of the multiple subintervals which are obtained by evenly dividing the target time interval 104. In this case， the time length of the second subinterval 304 may be equal to the first subinterval 102.

In the embodiments where the reference time interval includes a plurality of second subintervals 304 in the receiving mode， the communication device 110 may detect a plurality of second subinterval states of the channel. The second subinterval states indicate whether the channel is idle in the plurality of second subintervals 304. Then， the communication device 110 may determine the probability based on the plurality of second subinterval states. Now， an example process for predicting the first subinterval state will be described with reference to the following Equations (1) and (2) .

In this example， for the plurality of second subintervals 304， the second subinterval states are given in Equation (1) ：

where S (i) indicates whether the channel is idle in the ith subinterval of the reference time interval 302， and N is the number of the second subintervals 304. The probability that the channel is idle in the plurality of second subintervals 304 will be the probability that S (i) ＝0， which is represented as P (S (i) ＝ 0) . Then， P (S (i) ＝ 0) will be calculated by Equation (2) ：

After P (S (i) ＝ 0) is calculated， the first subinterval state may be determined by the following operations： (1) a random number X subjecting to uniform distribution over [0， 1] is generated， that is， X～U (0， 1) ； (2) if X ≤ P (S (i) ＝ 0) ， the first subinterval state is considered to be idle； otherwise， it is busy.

It is to be understood that other historically statistic idle information on the channel state is possible rather than the probability that the channel is idle in the reference time interval. For example， the prediction may also be based on measured power level of the channel in the reference time interval. Furthermore， in addition to the historically statistic information， the predication may be based on other information associated with the channel state.

Still with reference to Fig. 2， after the first subinterval state is predicted， the method 200 proceeds to block 204， where the communication device 110 determines an interval state of the channel at least in part based on the first subinterval state. The interval state indicates whether the channel is idle in the target time interval 104. As described above， in some embodiments， the target time interval 104 may be evenly divided into the multiple subintervals， and the first subinterval 102 may be one of the multiple subintervals. In these embodiments， the interval state may be determined further based on other subinterval states of the channel in other subintervals within the target time interval 104. For the sake of discussion， one of other subintervals will be referred to as a third subinterval， and one of other subinterval states will be referred to as a third subinterval state.

An example process of determining the interval state based on the subinterval states in the first subinterval and the third subintervals will be described with reference to Fig. 4 which shows a flowchart of an example method 400 for determining the interval state according to some embodiments of the present disclosure. The method 400 can also be implemented by the communication device 110.

As shown， in block 402， the communication device 110 obtains a plurality of third subinterval states of the channel. The third subinterval states indicate whether the channel is idle in the plurality of third subintervals within the target time interval. According to embodiments of the present invention， the communication device 110 may operate in the receiving or transmitting mode in the third subintervals. Accordingly， the third subinterval states may be obtained by power measurements of the channel or by the prediction method as described above with reference to block 202.

Then， in block 404， the communication device 110 determines a count of idle subintervals from the first subinterval and the plurality of third subintervals. The idle subintervals refer to the subintervals in which the channel is idle. Next， in block 406， if the count of idle subintervals exceeds a threshold， the communication device 110 determines that the channel is idle in the target time interval. Now， an example process for determining the interval state will be described with reference to the following Equations (3) and (4) .

In this example， the target time interval represented as T is evenly divided into M subintervals represented as Ts， as illustrated in Equation (3) ：

T ＝ M *Ts， (3)

For each subinterval Ts， the corresponding subinterval state is given in Equation (4) ：

where S (j) indicates whether the channel is idle in the jth subinterval of the target time interval T. S (j) may represent a detected channel state in the receiving mode and a predicated channel state in the transmitting mode. As used herein， the term “detected channel state” refers to a channel state that is obtained by channel detection， such as power measurements， and the term “predicted channel state” refers to a channel state that is obtained by the prediction method according to embodiments of the present disclosure.

Then， it is determined the number of the idle subintervals in which the channel is idle. If the number of the idle subintervals is bigger than a threshold， the channel is considered to be idle in the target time interval. Otherwise， the channel is busy.

Fig. 5 shows a flowchart of an example method 500 for determining the channel state in the CCA procedure in accordance with some embodiments of the present disclosure. The method 500 can also be implemented by the communication device 110.

In this example， two target time intervals T₀ and T₁ are involved in the CCA procedure. For the sake of discussion， the target time interval T₀ will be referred to as a first target time interval T₀， and the target time interval T₁ will be referred to as a second target time interval T₁. Accordingly， the channel state in the first target time interval will be referred to as a first interval state of the channel， and the channel state in the second target time interval will be referred to as a second interval state of the channel.

As shown， in block 502， where a back-off counter is drawn， which is preset， for example， as C. In block 504， in the first target time interval T₀， the first interval state of the channel is determined. In this example， the first target time interval T₀ is evenly divided into a plurality of subintervals. For each subinterval， the subinterval state of the channel may be detected in block 518 or predicted in block 520， which depends on the operation mode of the communication device 110. Then， the interval state may be determined in block 522. The processes are similar to the

methods

200 and 400 described above with reference to Figs. 2 to 4， and the details thereof will be omitted.

Next， in block 506， it is determined whether the first interval state indicates that the channel is idle in the first time interval T₀. If no， the method 500 returns to block 504， and the determination of the first interval state will be performed again. If the channel is determined to be idle in block 506， the method 500 proceeds to block 508， where it is determined whether C is above 0. If no， the method 500 proceeds to block 516 which will be discussed later. If C ＞ 0， the method 500 proceeds to block 510， where the second interval state of the channel is determined in the second target time interval T₁. Likewise， the determination processes are similar to the

methods

200 and 400 described above with reference to Figs. 2 and 3， and the details thereof will be omitted.

Then， in block 512， it is determined whether the second interval state indicates that the channel is idle in the second time interval T₁. If no， the method 500 also returns to block 504 and restarts the determination of the first interval state in the first time interval T₀. If the channel is determined to be idle in block 512， the method 500 proceeds to block 514， where the count C of the counter is subtracted by one. Next， the method 500 returns to block 508 where it is determined again whether the current count is above 0. IfC ＞ 0， the second interval state will be determined once more. If C＝0， the method 500 proceeds to block 516， where the communication device 110 initiates transmission in the idle channel.

Fig. 6 shows a block diagram of a communication device 600 in accordance with some embodiments of the present disclosure. The communication device 600 can be considered as an example implementation of the communication device 110 as shown in Fig. 1.

As shown， the communication device 600 comprises a predicting unit 602 and a state determining unit 604. The predicting unit 602 is configured to predict a first subinterval state of a channel which. The first subinterval state indicates whether the channel is idle in a first subinterval of a target time interval in which the communication device 600 operates in the transmitting mode. Furthermore， the state determining unit 604 is configured to determine an interval state of the channel at least in part based on the first subinterval state of the channel. The interval state indicates whether the channel is idle in the target time interval.

In some embodiments， the communication device 600 may further comprise a probability determining unit 606 configured to determine a probability that the channel is idle in a reference time interval prior to the first time-interval. The communication device 600 operates in the receiving mode in the reference time interval. In these embodiments， the predicting unit 602 may be configured to predict the first subinterval state based on the determined probability. In some embodiments， the reference time interval may be partially overlapped with the target time interval.

In some embodiments， the communication device 600 may further comprise a state detecting unit 608 configured to detect a plurality of second subinterval states of the channel. The second subinterval states indicate whether the channel is idle in a plurality of second subintervals of the reference time interval. In these embodiments， the probability determining unit 606 may be configured to determine the probability based on the plurality of second subinterval states.

In some embodiments， the communication device 600 may further comprise a state detecting unit 608 configured to detect a plurality of second subinterval states of the channel. The second subinterval states indicate whether the channel is idle in a plurality of second subintervals of the reference time interval.

In some embodiments， the state determining unit 604 may comprise a state obtaining unit configured to obtain a plurality of third subinterval states of the channel， the plurality of third subinterval states indicating whether the channel is idle in a plurality of third subintervals of the target time interval； a counting unit configured to determine a count of idle subintervals from the first subinterval and the plurality of third subintervals， the channel being idle in the idle subintervals； and a first state determining unit configured to，in response to the count of idle subintervals exceeding a threshold， determining that the channel is idle in the target time interval.

It should be appreciated that units included in the communication device 600 correspond to the blocks of the

methods

200， 400， and 500. Therefore， all operations and features described above with reference to Figs. 2 to 5 are likewise applicable to the units included in the communication device 600 and have similar effects. For the purpose of simplification， the details will be omitted.

The units included in the communication device 600 may be implemented in various manners， including software， hardware， firmware， or any combination thereof. In one embodiment， one or more units may be implemented using software and/or firmware， for example， machine-executable instructions stored on the storage medium. In addition to or instead of machine-executable instructions， parts or all of the units in the communication device 500 may be implemented， at least in part， by one or more hardware logic components. For example， and without limitation， illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs) ， Application-specific Integrated Circuits (ASICs) ， Application-specific Standard Products (ASSPs) ， System-on-a-chip systems (SOCs) ， Complex Programmable Logic Devices (CPLDs) ， and the like.

Fig. 7 is a simplified block diagram of a communication device 700 that is suitable for implementing embodiments of the present disclosure. The communication device 700 can be considered as a further example implementation of the communication device 110 as shown in Fig. 1.

As shown， the communication device 700 includes a processor 710， a memory 720 coupled to the processor 710， a suitable transmitter (TX) and receiver (RX) 740 coupled to the processor 710， and a communication interface 750 coupled to the processor 710. The memory 710 stores at least a part of a program 730. The TX/RX 740 is for bidirectional wireless communications. The TX/RX 740 has at least one antenna to facilitate communication， though in practice an Access Node mentioned in this application may have several ones. The communication interface 750 may represent any interface that is necessary for communication with other network elements， such as X2 interface for bidirectional communications between eNBs， S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the eNB， Un interface for communication between the eNB and a relay node (RN) ， or Uu interface for communication between the eNB and a terminal device.

The program 730 is assumed to include program instructions that， when executed by the associated processor 710， enable the communication device 700 to operate in accordance with the embodiments of the present disclosure， as discussed herein with reference to Figs. 2 to 4. The embodiments herein may be implemented by computer software executable by the processor 710 of the communication device 700， or by hardware， or by a combination of software and hardware. The processor 710 may be configured to implement various embodiments of the present disclosure. Furthermore， a combination of the processor 710 and memory 710 may form processing means adapted to implement various embodiments of the present disclosure.

The memory 710 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology， such as semiconductor based memory devices， magnetic memory devices and systems， optical memory devices and systems， fixed memory and removable memory， as non-limiting examples. While only one memory 710 is shown in the communication device 700， there may be several physically distinct memory modules in the communication device 700. The processor 710 may be of any type suitable to the local technical environment， and may include one or more of general purpose computers， special purpose computers， microprocessors， digital signal processors (DSPs) and processors based on multicore processor architecture， as non-limiting examples. The communication device 700 may have multiple processors， such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

Generally， various embodiments of the present disclosure may be implemented in hardware or special purpose circuits， software， logic or any combination thereof. Some aspects may be implemented in hardware， while other aspects may be implemented in firmware or software which may be executed by a controller， microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams， flowcharts， or using some other pictorial representation， it will be appreciated that the blocks， apparatus， systems， techniques or methods described herein may be implemented in， as non-limiting examples， hardware， software， firmware， special purpose circuits or logic， general purpose hardware or controller or other computing devices， or some combination thereof.

By way of example， embodiments of the present disclosure can be described in the general context of machine-executable instructions， such as those included in program modules， being executed in a device on a target real or virtual processor. Generally， program modules include routines， programs， libraries， objects， classes， components， data structures， or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device， program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer， special purpose computer， or other programmable data processing apparatus， such that the program codes， when executed by the processor or controller， cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine， partly on the machine， as a stand-alone software package， partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of this disclosure， a machine readable medium may be any tangible medium that may contain， or store a program for use by or in connection with an instruction execution system， apparatus， or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic， magnetic， optical， electromagnetic， infrared， or semiconductor system， apparatus， or device， or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires， a portable computer diskette， a hard disk， a random access memory (RAM) ， a read-only memory (ROM) ， an erasable programmable read-only memory (EPROM or Flash memory) ， an optical fiber， a portable compact disc read-only memory (CD-ROM) ， an optical storage device， a magnetic storage device， or any suitable combination of the foregoing.

Further， while operations are depicted in a particular order， this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order， or that all illustrated operations be performed， to achieve desirable results. In certain circumstances， multitasking and parallel processing may be advantageous. Likewise， while several specific implementation details are contained in the above discussions， these should not be construed as limitations on the scope of the present disclosure， but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely， various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts， it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather， the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A method (200) implemented by a communication device (110， 600， 700) ， comprising：

predicting (202) a first subinterval state of a channel， the first subinterval state indicating whether the channel is idle in a first subinterval (102) of a target time interval (104) ， the communication device (110， 600， 700) operating in a transmitting mode in the first subinterval (102) ； and

determining (204) an interval state of the channel at least in part based on the first subinterval state of the channel， the interval state indicating whether the channel is idle in the target time interval (104) .
The method (200) of claim 1， wherein predicting (202) the first subinterval state comprises：

determining a probability that the channel is idle in a reference time interval (302) prior to the first subinterval (102) ， the communication device (110， 600， 700) operating in a receiving mode in the reference time interval (302) ； and

predicting the first subinterval state based on the determined probability.
The method (200) of claim 2， wherein determining the probability comprises：

detecting a plurality of second subinterval states of the channel， the second subinterval states indicating whether the channel is idle in a plurality of second subintervals (304) of the reference time interval (302) ； and

determining the probability based on the plurality of second subinterval states.
The method (200) of any of claims 2-3， wherein the reference time interval (302) is partially overlapped with the target time interval (104) .
The method (200) of claim 1， wherein determining (204) the interval state comprises：

obtaining (402) a plurality of third subinterval states of the channel， the plurality of third subinterval states indicating whether the channel is idle in a plurality of third subintervals of the target time interval (104) ；

determining (404) a count of idle subintervals from the first subinterval and the plurality of third subintervals， the channel being idle in the idle subintervals； and

in response to the count of idle subintervals exceeding a threshold， determining (406) that the channel is idle in the target time interval (104) .
A communication device (110， 600， 700) ， comprising：

a predicting unit (602) configured to predict a first subinterval state of a channel， the first subinterval state indicating whether the channel is idle in a first subinterval (102) of a target time interval (104) ， the communication device (110， 600， 700) operating in a transmitting mode in the first subinterval (102) ； and

a state determining unit (604) configured to determine an interval state of the channel at least in part based on the first subinterval state of the channel， the interval state indicating whether the channel is idle in the target time interval (104) .
The communication device (110， 600， 700) of claim 6， further comprising：

a probability determining unit (606) configured to determine a probability that the channel is idle in a reference time interval (302) prior to the first subinterval (102) ， the communication device (110， 600， 700) operating in a receiving mode in the reference time interval (302) ，

wherein the predicting unit (602) is configured to predict the first subinterval state based on the determined probability.
The communication device (110， 600， 700) of claim 7， further comprising：

a state detecting unit (608) configured to detect a plurality of second subinterval states of the channel， the second subinterval states indicating whether the channel is idle in a plurality of second subintervals (304) of the reference time interval (302) ； and

wherein the probability determining unit (606) is configured to determine the probability based on the plurality of second subinterval states.
The communication device (110， 600， 700) of any of claims 7-8， wherein the reference time interval (302) is partially overlapped with the target time interval (104) .
The communication device (110， 600， 700) of claim 6， wherein the state determining unit (608) comprises：

a state obtaining unit configured to obtain a plurality of third subinterval states of the channel， the plurality of third subinterval states indicating whether the channel is idle in a plurality of third subintervals of the target time interval (104) ；

a counting unit configured to determine a count of idle subintervals from the first subinterval and the plurality of third subintervals， the channel being idle in the idle subintervals； and

a first state determining unit configured to， in response to the count of idle subintervals exceeding a threshold， determining that the channel is idle in the target time interval (104) .
A communication device (110， 600， 700) ， comprising：

a processor (710) configured to perform the method (200) according to any of claims 1 to 5.
A communication device (110， 600， 700) ， comprising means operative to perform the method (200) according to any of claims 1 to 5.
A computer program product being tangibly stored on a computer readable storage medium and including instructions which， when executed on at least one processor (710) ， cause the at least one processor (710) to carry out the method (200) according to any of claims 1 to 5.