KR102159979B1 - Method and apparatus for transmission on aggregated unlicensed multi-carrier - Google Patents

Abstract

The present invention relates to an unlicensed band multi-carrier combined transmission method and an apparatus thereof. According to the present invention, the method comprises the steps of grouping unlicensed band multiple carriers into a plurality of transport carrier groups and a guard carrier group positioned between the plurality of transport carrier groups, selecting a primary carrier and a secondary carrier separately in each transport carrier group, and initiating data transmission by independently performing a backoff process for each transport carrier group according to a listen before talk (LBT) B type mechanism, preventing the LBT mechanism from operating inefficiently due to power leakage between carriers during data transmission.

Description

Unlicensed band multi-carrier combined transmission method and apparatus {METHOD AND APPARATUS FOR TRANSMISSION ON AGGREGATED UNLICENSED MULTI-CARRIER}

The present invention relates to a multi-carrier combined transmission method and apparatus, and more particularly, to a method and apparatus for transmitting data through unlicensed band multi-carrier combination based on an LBT.

With the development of information and communication technology, various wireless communication technologies have been developed. Wireless communication technology can be classified according to whether the frequency band used is a licensed band or an unlicensed band.

The licensed band is exclusively licensed to a specific operator, and the wireless communication technology using the licensed band can provide better reliability and communication quality than the wireless communication technology using the unlicensed band.

Representative wireless communication technologies using licensed bands include 3GPP (3rd Generation Partnership Project), LTE (Long Term Evolution), LTE-A (Long Term Evolution Advanced), etc., and base stations and UEs (User Equipment) that support LTE Can transmit and receive signals through the licensed band.

A typical wireless communication technology using an unlicensed band is WLAN (Wireless Local Area Network) specified in the IEEE 802.11 standard, and each of the access points and stations supporting the WLAN can transmit and receive data through the unlicensed band.

Meanwhile, in order to adequately cope with the explosive increase in mobile traffic in recent years, it is required to secure an additional licensed band in addition to the existing licensed band. However, in allocating finite frequency resources, since a frequency band auction method is used between each service provider, an astronomical cost is required for each communication service provider to secure an additional licensed band. In order to solve this cost problem, a method of providing an LTE or LTE-A service through an unlicensed band has been proposed.

When providing an LTE or LTE-A service through an unlicensed band, the base station equipment (eNB) and the user terminal (UE) must share the unlicensed band frequency with communication nodes supporting WLAN, for example, access points and stations.

In order for the base station equipment, which is a communication node for LTE or LTE-A, and communication nodes supporting the user terminal and WLAN to coexist in the unlicensed band frequency, a clear channel assessment (CCA) or extended CCA (ECCA) process, a random backoff ) It is known to utilize LBT (Listen before Talk) mechanisms such as processes.

Multi-carrier LBT mechanisms are generally classified into two types. Hereinafter, two types of LBT mechanisms will be briefly described with reference to FIGS. 1 and 2.

1 is a timing chart for explaining a type A of a multi-carrier LBT mechanism.

Referring to FIG. 1, for example, five unlicensed band frequency channels are shown, and an eNB (envolved Node B) independently performs a backoff process for each channel.

The eNB detects the state of each channel by performing an available channel evaluation (CCA) for each channel during the Td period. A backoff counter is randomly set for each channel, and when it is detected that the channel is idle as a result of the available channel evaluation, the backoff counter decreases every time slot for the idle channel. When the backoff counter of each channel becomes zero, data transmission is started for each channel. The type A method has an advantage in that the back-off process is performed for each channel, and thus it can appropriately respond to the state of each channel.

On the other hand, the Type B scheme is similar to a broadband channel access mechanism such as Wi-Fi. Referring to FIG. 2, in the type B scheme, the eNB performs a backoff process only on one primary carrier among five unlicensed band frequency channels.

The remaining four carriers are referred to as secondary carriers, and for these secondary carriers, short-term available channel evaluation (Short CCA) is performed during the Tmc period just before the backoff counter for the primary carrier becomes zero.

Thereafter, when the backoff counter for the primary carrier becomes zero, data is transmitted through the primary carrier and data transmission is started through the secondary carrier detected as idle as a result of short-term available channel evaluation.

Hereinafter, the effect of power leakage between carriers on the LBT mechanism will be described with reference to FIGS. 3 and 4.

3 is a graph showing an effect detected by a neighboring carrier due to leakage of transmission power when data is transmitted through a carrier having a bandwidth of 20 MHz in a 5 GHz unlicensed band.

3, when the eNB transmits data through the i-th carrier with the maximum allowable power, e.g., 23dBm, the power leakage detected in the i-1th and i+1th carriers adjacent to each other is the center of each carrier. It is about -27.6 dBm in frequency. It can be seen that -40dBm is detected even in the far-distant carriers. This power leakage prevents the eNB from simultaneously transmitting data through multiple carriers in the LBT type A mechanism described above.

For example, in LAA (Licensed Assisted Access), the energy detection threshold of CCA ranges from -82 dBm to -62 dBm. Therefore, as shown in FIG. 4, when the eNB transmits data through channel 2 (CH#2) according to the LBT type A mechanism, because of the effect of power leakage of channel 2 on the adjacent channel, the eNB The state is recognized as a busy state, and the backoff counters for channels 0, 1, 3, and 4 are stopped until data transmission through channel 2 is completed.

Therefore, when the LBT type A mechanism is used, data may not be simultaneously transmitted through multiple carriers due to power leakage between channels, which causes a problem that prevents efficient use of frequency resources.

Meanwhile, since the LBT type B mechanism performs a backoff process for only one primary carrier, power leakage due to data transmission of one channel does not disturb the backoff process of a neighboring channel.

However, since the LBT type B mechanism performs a backoff process for only one primary carrier, there is an inherent limitation in that it cannot adaptively respond to the state of each channel.

Therefore, the present invention is a multi-carrier combined transmission method capable of simultaneous data transmission through each channel while improving adaptability to each channel state by supplementing the disadvantages of the type A and type B LBT mechanisms in a communication environment where power leakage exists. And to provide an apparatus.

In the unlicensed band multi-carrier combined transmission method according to an embodiment of the present invention, grouping multiple carriers of the unlicensed band into a guard carrier group between two transport carrier groups and two transport carrier groups, and each transport carrier group is When the backoff counter of the primary carrier becomes zero by dividing the primary carrier into a secondary carrier consisting of the remaining carriers and performing the LBT process for the primary carrier and the secondary carrier, the secondary carrier is idle (IDLE) state. And initiating data transmission through the in carrier and the primary carrier.

In the unlicensed band multi-carrier combined transmission method according to another embodiment of the present invention, the guard carrier group is composed of one or a plurality of carriers of adjacent frequencies, and the number of carriers in the guard carrier group is the maximum power allowed during data transmission, data transmission It is characterized in that it is determined based on the extent of the influence of the power leakage on the adjacent carrier and the bandwidth of the carrier.

According to the unlicensed band multi-carrier combined transmission method according to another embodiment of the present invention, a carrier of a guard carrier group is selected so that a transmission capacity of the guard carrier group is minimized.

According to the unlicensed band multi-carrier combined transmission method according to another embodiment of the present invention, a transport carrier group until the transmission capacity of the entire unlicensed band multicarriers after grouping becomes smaller than the transmission capacity of the entire unlicensed band multicarriers before grouping. It characterized in that the grouping of the transport carrier group is additionally performed by repeating the grouping of the carriers of

According to the unlicensed band multi-carrier combined transmission method according to another embodiment of the present invention, the primary carrier is selected so that the transmission capacity of the entire unlicensed band multi-carrier is maximized.

As described above, according to various embodiments proposed in the present invention, the present invention overcomes the problem of power leakage between adjacent carriers in a multi-carrier combined transmission method of an unlicensed band, and enables more efficient use of frequency resources. .

1 is a timing chart for explaining a type A of a multi-carrier LBT mechanism.
2 is a timing chart for explaining a type B of a multi-carrier LBT mechanism.
3 is a graph showing an effect of transmission power detected by a neighboring carrier when data is transmitted through a carrier having a bandwidth of 20 MHz in a 5 GHz unlicensed band.
4 is a timing chart for explaining a problem caused by power leakage from a data transmission carrier when type A is applied among the multi-carrier LBT mechanisms.
5 is a flowchart illustrating a method for combined transmission of multiple carriers in an unlicensed band according to an embodiment of the present invention.
6 is a diagram for explaining a grouping step in a method for combined transmission of multiple carriers in an unlicensed band according to an embodiment of the present invention.
7 shows an unlicensed band multi-carrier combined transmission apparatus according to an embodiment of the present invention.

Advantages and features of the embodiments disclosed in the present specification, and a method of achieving them will become apparent with reference to the embodiments described later together with the accompanying drawings. However, the embodiments to be proposed in the present disclosure are not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments are examples to those of ordinary skill in the art. It is only provided to fully inform the categories of the subjects.

The terms used in the present specification will be briefly described, and the disclosed embodiments will be described in detail.

Terms used in the present specification have selected general terms that are currently widely used as possible while considering the functions of the disclosed embodiments, but this may vary depending on the intention or precedent of a technician engaged in a related field, the emergence of new technologies, and the like. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning of the terms will be described in detail in the detailed description of the corresponding specification. Therefore, terms used in the present disclosure should be defined based on the meaning of the term and the contents of the entire specification, not the name of the term.

In this specification, expressions in the singular include plural expressions, unless the context clearly specifies that they are singular.

When a part of the specification is said to "include" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. In addition, the term "unit" used in the specification refers to a hardware component such as software, FPGA, or ASIC, and the "unit" performs certain roles. However, "unit" is not meant to be limited to software or hardware. The “unit” may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors. Thus, as an example, "unit" refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, Includes subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays and variables. The functions provided within the components and "units" may be combined into a smaller number of components and "units" or may be further separated into additional components and "units".

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. In addition, in the drawings, parts not related to the description are omitted in order to clearly describe the present invention.

Hereinafter, an unlicensed band multi-carrier combined transmission method according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6.

According to FIGS. 5 and 6, in step 510, for example, N unlicensed band multi-carriers (r ₁ , r ₂ ,,,, r _n ,,,, r _N ) are assigned to a first transmission carrier group (r ₁ ,,, r _{s -1} ), a guard carrier group (r _s ,,,r _e ), and a second transport carrier group (r _{e+ 1} ,,,r _N ).

In step 520, one primary carrier (eg, r ₁ ) is selected from the carriers of the first transport carrier group, and one primary carrier (eg, r _e+1 ) is selected from the carriers of the second transport carrier group.

Accordingly, the remaining carriers excluding the primary carrier (r ₁ ) in the first transport carrier group are secondary carriers, and the remaining carriers excluding the primary carrier (r _e+1 ) in the second transport carrier group are secondary carriers.

In step 530, data transmission is initiated by independently applying the LBT B type mechanism to each transport carrier group. Hereinafter, step 510 will be described in detail.

First, assume a set of N unlicensed band carriers that do not overlap each other. The indexes for each carrier are arranged in the order of increasing the center frequency of the carrier from 1 to N, and each carrier is assumed to have a bandwidth of 20 MHz.

When the probability that the eNB transmits data in the random timeslot through the carrier r _n is β _n , the link capacity secured by the eNB through the carrier r _n is as follows according to Shanon's capacity theory.

(1)

(One)

Here, BW is the bandwidth of the carrier and SINR is the signal-to-interference and noise ratio of the carrier.

Meanwhile, according to Bianchi's DCF model, β _n is a function of p _n representing the probability that energy exceeding the ED (Energy Detection) threshold is detected within one time slot, and can be expressed as in Equation (2) below. I can.

(2)

(2)

Here, CWmim is the minimum contention window size, and k represents the maximum backoff stage performed by the eNB of the LAA.

When the eNB performs the LBT type B mechanism for N carriers including the primary carrier r _i , the total transmission capacity can be expressed as Equation (3) below.

(3)

(3)

는 시간 T_mc 동안 단기 CCA 평가에 의하여 세컨더리 캐리어 r_j가 유휴상태로 감지될 때 세컨더리 캐리어 r_j를 통하여 전송이 개시될 확률을 나타낸다. Here, the first term on the right side represents the transmission capacity of the primary carrier r _i , and the second term represents the sum of the transmission capacity of the secondary carriers,

T _mc is a time during when the detected as a secondary carrier r _j is in an idle state by the short-term assessment CCA represents the probability of transmission is started through the secondary carrier r _j.

는 다음 식 (4)와 같이 구해진다.therefore,

Is obtained by the following equation (4).

(4)

(4)

As described above, in step 510, N carriers are divided into a first transport carrier group consisting of N ₁ carriers, a second transport carrier group consisting of N ₂ carriers, and a guard carrier group consisting of m carriers.

Therefore, the relationship between the total number of carriers and the number of carriers for each group is as shown in Equation (5) below.

N = N_One + N₂ +m (5)

First, in step 510, in order to divide the N unlicensed band multiple carriers as shown in Equation (5), the size (m) of the guard carrier group must be known first.

The guard carrier group is located between the first transport carrier group and the second transport carrier group, and when data is transmitted through the carriers of the first or second transport carrier group, the power leakage influences the second or first transport carrier group. It is in charge of blocking its influence so that it does not fall.

Therefore, the size of the guard carrier group (m) is based on the maximum allowable transmission power, the bandwidth of one carrier, and how far the power leakage of the transmission carrier affects the neighboring carrier when transmitting data through one carrier. It can be decided.

It is assumed that the number of guard carrier groups obtained based on the above factor is m. Next, when the initial carrier of the guard carrier group consisting of m carriers is selected, the entire guard carrier group can be specified.

That is, if the initial carrier of the guard carrier group is referred to as r _s and the number of carriers in the guard carrier group is referred to as m, the guard carrier group G _guard can be expressed as follows.

G _guard = {r _s ,··· ,r _e }, (e = s +m-1)

On the other hand, since the guard carrier group is a carrier group that is not used for data transmission, it causes a decrease in the transmission capacitor of all carriers. Therefore, in specifying the guard carrier group, it is preferable to select the initial carrier r _s so as to minimize deterioration of the entire transmission capacitor due to the guard carrier group.

This can be expressed as an equation as follows.

(6)

(6)

For example, it is desirable to select the initial carrier r _s so that carriers with a large amount of communication through Wi-Fi can be included in the guard carrier group. This is because, while the carriers are being used for Wi-Fi communication, they are not used for LTE communication anyway, so making these carriers belong to the guard carrier group can minimize the deterioration of the total transmission capacitor.

When the guard carrier group is specified as described above, the first transport carrier group and the second transport carrier group can be specified as follows.

G ₁ = {r ₁ ,... ,r _{s -1} }

G ₂ = {r _e+1 ,... ,r _N }

As described above, the process of grouping the unlicensed band multiple carriers into a first transport carrier group, a second transport carrier group, and a guard carrier group in step 510 has been described in detail.

Meanwhile, step 510 may include a process of comparing the total transmission capacity before and after grouping in addition to the above-described process. For example, if r _i1 and r _i2 are the primary carriers of the first and second transport carrier groups, respectively, the total transmission capacity before and after grouping can be compared as in the following equation.

(7)

(7)

As a result of the comparison, if the total transmission capacity after grouping is smaller than the total transmission capacity before grouping, that is, if the inequality (7) is not satisfied, it means that the total transmission capacity has decreased due to grouping, so grouping (G1, G2, Gguard ), and according to steps 520 and 530, specifying a primary carrier among all carriers, performing a backoff process according to the mechanism of the LBT B type for the specified primary and secondary carriers, and accordingly Data transmission can be initiated.

If, as a result of the comparison, the total transmission capacity after grouping is greater than the total transmission capacity before grouping, that is, satisfies the inequality (7), grouping may be performed again for each transport carrier group, thereby subdividing the transport carrier group.

Referring to FIG. 6, the grouping process performed again is described, by reapplying the aforementioned step 510 to the first transport carrier group G1, the G1 group may be subdivided into G11, G12, and Gg1.

Likewise, by reapplying the above-described step 510 to the second transport carrier group G2, the G2 group can be subdivided into G21, G22, and G2 again.

For the subdivided transport carrier groups (G11, G12), the transmission capacity before and after grouping can be compared as follows.

(8)

(8)

Here, N11 denotes the number of carriers in the transport carrier group G11, and N12 denotes the number of carriers in the transport carrier group G12.

If, as a result of comparison according to Equation (8), if the transmission capacity after grouping is smaller than the transmission capacity before grouping, that is, if the inequality (8) is not satisfied, it means that the transmission capacity is rather reduced due to grouping, Grouping (G11, G12, Gguard1) is discarded, and the primary carrier of the G1 group is specified among the first transport carrier group (G1) carriers according to steps 520 and 530, and the primary carrier and the secondary of the specified G1 group It is possible to perform a backoff process according to the mechanism of the LBT B type for the carrier and initiate data transmission accordingly. In this case, no further grouping steps are performed.

If, as a result of comparison according to Equation (8), the transmission capacity after grouping is greater than the transmission capacity before grouping, that is, if the inequality (8) is satisfied, grouping is performed again for each transport carrier group (G11, G12). Thus, the transport carrier group can be subdivided, and the grouping and comparison process can be repeatedly performed until the comparison result does not satisfy the equation.

In the same way, the transmission capacity for each group before and after grouping with respect to the subdivided transmission carrier groups G21 and G22 is compared as follows.

(9)

(9)

Here, N21 represents the number of carriers in the transport carrier group G21, and N22 represents the number of carriers in the transport carrier group G22.

If, as a result of the comparison according to Equation (9), if the transmission capacity after grouping is smaller than the transmission capacity before grouping, that is, if the inequality (9) is not satisfied, it means that the transmission capacity is lowered due to grouping. Grouping (G21, G22, Gguard2) is discarded, and according to steps 520 and 530, a primary carrier of the G2 group is specified among the carriers of the second transport carrier group (G2), and the specified primary carrier and the secondary carrier are On the other hand, the backoff process may be performed according to the LBT B type mechanism, and data transmission may be started accordingly. In this case, no further grouping steps are performed.

If, as a result of comparison according to Equation (9), the transmission capacity after grouping is greater than the transmission capacity before grouping, that is, if the inequality (9) is satisfied, grouping is performed again for each transport carrier group (G21, G22). Thus, the transport carrier group can be subdivided, and the grouping and comparison process can be repeatedly performed until the comparison result does not satisfy the equation.

The above has been described in detail the process of repeatedly performing grouping and comparison performed in step 510. Hereinafter, a process of selecting a primary carrier in step 520 will be described.

When the eNB selects a primary carrier for each transport carrier group in a transport carrier group (e.g., G1, G2, G11, G12, G21, G22, etc.), the selected primary carrier is used for carriers of the transport carrier group. On the other hand, it is preferable to apply a backoff process according to the LBT B-type mechanism and select a primary carrier capable of obtaining the maximum transmission capacity when performing data communication.

That is, it is preferable to select a carrier whose left-hand side value of Equation (3) is the maximum as the primary carrier of the transport carrier group.

(3)

(3)

In the above, the unlicensed band multi-carrier combined transmission method according to the present invention has been described with reference to various embodiments. Meanwhile, the present invention may be described as an unlicensed band multi-carrier combined transmission apparatus operating in a wireless communication network.

Referring to FIG. 7, the present invention is an unlicensed band multi-carrier combined transmission device or communication node 700 operating in a wireless communication network, and includes one or more microprocessors 710 and a memory 720 in which one or more instructions are stored. , One or more commands group multiple carriers of the unlicensed band into a guard carrier group between two transport carrier groups and two transport carrier groups, and each transport carrier group is a secondary carrier consisting of one primary carrier and the remaining carriers. The primary carrier and the secondary carrier perform the LBT process, and when the backoff counter of the primary carrier becomes zero, data transmission is initiated through the carrier and the primary carrier in the idle (IDLE) state among the secondary carriers. Characterized in that.

According to another embodiment of the present invention, the guard carrier group is composed of one or a plurality of carriers of adjacent frequencies, and one or more commands are the maximum power allowed during data transmission and the effect of power leakage on the adjacent carrier during data transmission. It is characterized in that the number of carriers in the guard carrier group is determined based on the degree and the bandwidth of the carriers.

According to another embodiment of the present invention, at least one command is characterized in that the carrier of the guard carrier group is selected so that the transmission capacity of the guard carrier group is minimized.

According to another embodiment of the present invention, one or more commands are applied to the carriers of the transport carrier group until the transmission capacity of the entire unlicensed band multicarriers after grouping becomes smaller than the transmission capacity of the entire unlicensed band multicarriers before grouping. The transport carrier group is additionally grouped by recursively recursively grouping.

According to another embodiment of the present invention, at least one command is characterized in that the primary carrier is selected so that the transmission capacity of the entire multi-carrier in the unlicensed band is maximized.

As described above, embodiments of the present invention have been described with reference to FIGS. 1 to 8, but the present invention is not limited to these embodiments and may be variously modified.

700 communication nodes
710 microprocessor
720 memory

Claims (10)

Grouping multiple carriers in an unlicensed band into a guard carrier group for blocking an effect of power leakage during data transmission between two transport carrier groups and the two transport carrier groups;
Dividing each of the transport carrier groups into one primary carrier and a secondary carrier consisting of the remaining carriers; And
By performing the LBT process for the primary carrier and the secondary carrier, when the backoff counter of the primary carrier becomes zero, data transmission is performed through an IDLE carrier among the secondary carriers and the primary carrier. Includes the steps to start,
The guard carrier group is composed of one or a plurality of carriers of adjacent frequencies, and the number of carriers in the guard carrier group is the maximum power allowed during data transmission, the degree of the effect of power leakage on the adjacent carrier during data transmission, and Is determined based on the bandwidth,
The carrier of the guard carrier group is selected so that the transmission capacity of the guard carrier group is minimized,
Recursively repeating the grouping of the carriers of the transport carrier group until the transmission capacity of the entire unlicensed band multicarriers after grouping becomes smaller than the transmission capacity of the entire unlicensed band multicarriers before grouping Thereby additionally grouping the transport carrier group,
The primary carrier is selected so that the transmission capacity of the entire multi-carrier in the unlicensed band is maximized,
Assuming a set of N non-overlapping unlicensed band carriers,
BW is the carrier bandwidth, SINR is the signal-to-interference-and-noise ratio of the carrier, β _n is to say eNB has chances to transmit data at a random time slot through the carrier r _n, link capacitor to eNB is secured via a carrier r _n City,

(One)
Can be expressed as
CWmim is the minimum contention window size, and k is the maximum backoff stage performed by the eNB of LAA,
β _n is a function of p _n representing the probability that energy exceeding the ED (Energy Detection) threshold is detected within one time slot,

(2)
Can be expressed as
When the eNB performs the LBT type B mechanism for N carriers including the primary carrier r _i , the total transmission capacity,

(3)
Can be expressed as
Here, the first term on the right side represents the transmission capacity of the primary carrier r _i , and the second term represents the sum of the transmission capacity of the secondary carriers,

Is detected as a time when a T _mc for a short-term assessment CCA secondary carrier by r _j is idle, indicates the probability that the transmission is initiated over the secondary carrier r _j, this,

(4)
Can be expressed as
The unlicensed band multi-carrier combined transmission method, characterized in that a carrier whose left-side value of Equation (3) is maximum is selected as a primary carrier of the transport carrier group. delete delete delete delete An unlicensed band multi-carrier combined transmission device operating in a wireless communication network,
One or more microprocessors; And
Includes a memory in which one or more instructions executed through the one or more microprocessors are stored,
The one or more commands,
Grouping multiple carriers of an unlicensed band into a guard carrier group for blocking the effect of power leakage during data transmission between two transport carrier groups and the two transport carrier groups,
Each of the transport carrier groups is divided into one primary carrier and a secondary carrier consisting of the remaining carriers,
By performing the LBT process for the primary carrier and the secondary carrier, when the backoff counter of the primary carrier becomes zero, data transmission is performed through an IDLE carrier among the secondary carriers and the primary carrier. Start,
The guard carrier group is composed of one or a plurality of carriers of adjacent frequencies, and the one or more commands are based on the maximum power allowed during data transmission, the extent of the effect of power leakage on the adjacent carrier during data transmission, and the bandwidth of the carrier. To determine the number of carriers in the guard carrier group,
The one or more commands are to select a carrier of the guard carrier group so that the transmission capacity of the guard carrier group is minimized,
The one or more commands are recursively repeated for the carriers of the transmission carrier group until the transmission capacity of the entire unlicensed band multicarriers after grouping becomes smaller than the transmission capacity of the entire unlicensed band multicarriers before grouping. By grouping, the transport carrier group is additionally grouped,
The one or more commands are to select a primary carrier such that the transmission capacity of the entire multi-carrier in the unlicensed band is maximized,
Assuming a set of N non-overlapping unlicensed band carriers,
BW is the carrier bandwidth, SINR is the signal-to-interference-and-noise ratio of the carrier, β _n is to say eNB has chances to transmit data at a random time slot through the carrier r _n, link capacitor to eNB is secured via a carrier r _n City,

(One)
Can be expressed as
CWmim is the minimum contention window size, and k is the maximum backoff stage performed by the eNB of LAA,
β _n is a function of p _n representing the probability that energy exceeding the ED (Energy Detection) threshold is detected within one time slot,

(2)
Can be expressed as
When the eNB performs the LBT type B mechanism for N carriers including the primary carrier r _i , the total transmission capacity,

(3)
Can be expressed as
Here, the first term on the right side represents the transmission capacity of the primary carrier r _i , and the second term represents the sum of the transmission capacity of the secondary carriers,

Is detected as a time when a T _mc for a short-term assessment CCA secondary carrier by r _j is idle, indicates the probability that the transmission is initiated over the secondary carrier r _j, this,

(4)
Can be expressed as
The unlicensed band multi-carrier combined transmission device, characterized in that a carrier whose left-side value of Equation (3) is maximum is selected as the primary carrier of the transport carrier group.
delete delete delete delete

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