KR20170127634A - Method, apparatus, and system for transmitting ul shared/control channel(s)/signal(s) in unlicensed spectrum - Google Patents

Abstract

The present invention relates to a method, apparatus and system for effectively performing clear channel assessment (CCA) during a listen-before-talk procedure in performing a channel access for uplink channel(s) and signal transmission in unlicensed spectrum communication, and a method, apparatus and system for the behavior of a terminal after a UL LBT failure. According to an embodiment of the present invention, a method, apparatus and system for unlicensed spectrum communication can be provided.

Description

TECHNICAL FIELD [0001] The present invention relates to an uplink channel and a signal transmission method, an apparatus, and a system in a license-exempt band.

The present invention relates to a method for performing uplink channel (s) and signal transmission in a license-exempt band communication and performing clear channel assesment (CCA) during the procedure of Listen before talk when performing channel access, And more particularly, to a method, apparatus, and system for transmitting data in an uplink.

Recently, as the spread of mobile devices has expanded, wireless LAN technology capable of providing fast wireless Internet service has attracted much attention. Wireless LAN technology is a technology that enables wireless devices such as smart phones, smart pads, laptop computers, portable multimedia players, and embedded devices to wirelessly connect to the Internet at home, to be.

IEEE (Institute of Electrical and Electronics Engineers) Since 802.11 supports the initial wireless LAN technology using 2.4 GHz frequency, various technology standards are being put into practical use or under development. First, IEEE 802.11b supports a communication speed of up to 11 Mbps while using a frequency of 2.4 GHz band. IEEE 802.11a, which has been commercialized since IEEE 802.11b, uses the frequency of the 5 GHz band instead of the 2.4 GHz band, thereby reducing the influence on the interference compared to the frequency of the highly congested 2.4 GHz band. Orthogonal Frequency Division Multiplexing To improve communication speed up to 54Mbps. However, IEEE 802.11a has a short communication distance compared to IEEE 802.11b. IEEE 802.11g, like IEEE 802.11b, uses a frequency of 2.4GHz band to achieve a communication speed of up to 54Mbps and has received considerable attention because it meets backward compatibility. It is in the lead.

On the other hand, there is IEEE 802.11n as a technical standard established to overcome the limit of the communication speed pointed out as a weak point in the wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and to extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with data rates of up to 540 Mbps or higher, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology. In addition, the specification may use a coding scheme that transfers multiple duplicate copies to increase data reliability.

As the spread of the wireless LAN is activated and the applications using it are diversified, there is a need for a new wireless LAN system to support a very high throughput (VHT) higher than the data processing speed supported by IEEE 802.11n . IEEE 802.11ac supports wide bandwidth (80MHz ~ 160MHz) at 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but for backward compatibility with existing 2.4GHz band products, early 11ac chipsets will also support operation in the 2.4GHz band. Theoretically, according to this standard, the wireless LAN speed of multiple stations is at least 1Gbps and the maximum single link speed is at least 500Mbps. This is achieved through the expansion of the concept of wireless interfaces adopted in 802.11n, including wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multiuser MIMO, and high density modulation (up to 256 QAM) . Meanwhile, IEEE 802.11ad is a method of transmitting data using a 60 GHz band instead of the existing 2.4 GHz / 5 GHz. IEEE 802.11ad is a transmission specification that uses beamforming technology to provide speeds of up to 7 Gbps, making it suitable for high bitrate video streaming, such as large amounts of data or uncompressed HD video. However, the 60GHz frequency band has a disadvantage in that it is difficult to pass through obstacles, and therefore, it can be used only between devices in a near space.

In recent years, as a next-generation wireless LAN standard after 802.11ac and 802.11ad, there has been a continuing discussion to provide high-efficiency and high-performance wireless LAN communication technology in a high-density environment. That is, in the next generation wireless LAN environment, communication with high frequency efficiency should be provided in the presence of a high density station and an access point (AP), and various techniques are required to realize this.

Meanwhile, due to the proliferation of smart devices in recent years, mobile traffic has been increasing, and it is becoming difficult to handle the increased data usage for providing cellular communication service only in the existing authorized frequency spectrum or LTE-licensed frequency band.

In this situation, the use of unlicensed frequency spectrum or LTE-Unlicensed frequency band (for example, 2.4 GHz band, 5.8 GHz band, etc.) for providing cellular communication service is being sought as a solution to the lack of spectrum problem.

However, in the case of the unlicensed band, since the communication service provider does not secure the exclusive use of the frequency license through the auction process, and only the certain level of the adjacent band protection regulations is satisfied, a plurality of communication facilities can be used simultaneously without restriction. It is difficult to guarantee a communication quality at a level that can be achieved, and interference problems may occur with devices that are wirelessly communicating using an unlicensed band (e.g., Wi-Fi network).

Therefore, in order to establish the LTE technology in the unlicensed band, the coexistence with the existing unlicensed band device and the study for the efficient sharing of the wireless channel should be performed proactively. That is, a robust coexistence mechanism (RCM) should be developed so that devices using LTE technology in the unlicensed band do not affect existing unlicensed band devices.

Regarding standardization, telecommunication carriers such as NTT DoCoMo, China Mobile and Verizon, including manufacturers such as Qualcomm in 3GPP, actively insist on the introduction of the standard for LTE technology in the license-exempt band actively. However, many members are more cautious because they are a new technology that can shake up the existing carrier's business model based on securing the frequency of LTE technology in the licensed band. Therefore, it is expected that LTE technology in the license-exempted band will be standardized through 3GPP after Release 13, and it is expected that it will be connected to actual commercial service from the second half of 2016. In the case of foreign countries, there is a basis for commercialization of various services and new technologies without specifying usage under the conditions of compliance with the basic radio wave use etiquette in the frequency sharing band or the license-exempt small power band. On the other hand, most of the license-exempt bands including the ISM band are operated by the use designation in Korea, and technical research and related policies should be preceded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a method, an apparatus, and a system for a license-exempt band communication.

The present invention also has a purpose of providing a carrier synchronization method for transmission with a wider bandwidth.

According to an embodiment of the present invention, a method, apparatus and system for license-exempt band communication can be provided.

According to the embodiment of the present invention described above, carrier synchronization for wider bandwidth transmission in the license-exempt band can be performed.

The present invention is applicable to various communication devices such as a station or an access point using license-exempt band communication, a station using a cellular communication, or a base station.

1 is a diagram illustrating a CSMA (Carrier Sense Multiple Access) / CA (Collision Avoidance) method used in wireless LAN communication.
2 is a diagram illustrating an embodiment of a wireless communication method using a CCA (Clear Channel Assessment) technique.
3 is a diagram illustrating an example of a superposed BSS environment.
FIG. 4 shows an example of a radio frame structure used in a wireless communication system.
FIG. 5 illustrates an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system.
6 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.
FIG. 7 illustrates a radio frame structure for transmission of a synchronization signal (SS).
8 is a diagram illustrating a structure of a downlink radio frame used in an LTE system.
FIG. 9 illustrates a configuration of a cell specific common reference signal.
10 shows an example of a UL subframe structure used in a wireless communication system.
11 is a conceptual diagram illustrating a carrier aggregation (CA) technique.
12 is a diagram for explaining Single Carrier Communication and Multiple Carrier Communication.
13 is a diagram showing an example in which a cross carrier scheduling technique is applied.
FIG. 14 is a diagram for explaining a licensed assisted access (LAA) service environment.
15 is a diagram illustrating a deployment scenario of a terminal and a base station in an LAA service environment.
16 is a block diagram showing a configuration of a terminal and a base station according to an embodiment of the present invention.
17 is a block diagram illustrating a category-4 LBT procedure in an LAA according to an embodiment of the present invention.
18 is a block diagram illustrating a category-4 LBT procedure in an LAA according to another embodiment of the present invention.
FIG. 19 shows an example of a case where a channel is idle as one embodiment of the present invention. The channel priority class 3 is used as a defer duration, and 19- (a) and a channel priority class 3 extracted as Ninit = 1 (B), where Ninit = 0 is extracted.
FIG. 20 illustrates an example of a case where a channel is busy in one slot, using channel priority class 3 as a defer duration and 20- (a) extracted from Ninit = 2 and channel priority class 3 as an embodiment of the present invention (B) in which Ninit = 1 is extracted.
21 is a diagram illustrating a case where UL transmission is continuously transmitted after Ongoing DL transmission according to an embodiment of the present invention.
FIG. 22 is a diagram illustrating a case in which UL transmission is consecutively transmitted after DL transmission, and a DL that receives an UL grant and a DL that precedes UL transmission are discontinuous.
23 is a diagram illustrating a case where a PDCCH including only an UL grant is transmitted without PDSCH transmission in any one subframe according to an embodiment of the present invention.
FIG. 24 is a diagram illustrating a case where an EPDCCH including only an UL grant is transmitted without transmitting a PDSCH to an arbitrary subframe according to an embodiment of the present invention.
FIG. 25 is a diagram illustrating a case where a subframe that transmits only an UL grant and an LBT of a subframe (s) that performs PDSCH transmission are independently performed without PDSCH transmission as an embodiment of the present invention.
26 is a diagram illustrating a case where a reservation signal (s) is transmitted to a blanked OFDM symbol (s) in a subframe transmitting a PDCCH including only an UL grant without PDSCH transmission in any one subframe according to an embodiment of the present invention .
FIG. 27 is a diagram illustrating a case where uplink transmission is performed after LBT success of a PUSCH configured to transmit UCI or A / N.
FIG. 28 is a diagram illustrating a case where uplink transmission can not be performed due to LBT failure of a PUSCH configured to transmit UCI or A / N.
29- (a) and (b) illustrate one embodiment of the present invention. In the PUSCH configured to transmit UCI or A / N, one LBT is performed at the LBT point of the PUSCH and the A / N can be transmitted And performing CCA with a single sensing interval at the symbol position of the SC-FDMA.
30- (a) and 30 (b) illustrate another embodiment of the present invention, in which a LBT is performed at a LBT point of a PUSCH and an A / N is transmitted for a PUSCH configured to transmit UCI or A / N FIG. 4 is a diagram illustrating a case of performing LBT in two stages in which CCA having a single sensing interval is performed at symbol positions of a slot-based SC-FDMA in a slot.
31- (a) and 31 (b) illustrate a case of performing two-stage LBT at the LBT point of the PUSCH with respect to the PUSCH configured to transmit UCI or A / N as another embodiment of the present invention.
32 shows that UL transmission is performed using two stage grants.

As used herein, terms used in the present invention are selected from general terms that are widely used in the present invention while taking into account the functions of the present invention. However, these terms may vary depending on the intention of a person skilled in the art, custom or the emergence of new technology. Also, in certain cases, there may be a term arbitrarily selected by the applicant, and in this case, the meaning thereof will be described in the description of the corresponding invention. Therefore, it is intended that the terminology used herein should be interpreted relative to the actual meaning of the term, rather than the nomenclature, and its content throughout the specification.

Throughout the specification, when a configuration is referred to as being "connected" to another configuration, it is not limited to the case where it is "directly connected," but also includes "electrically connected" do. Also, when an element is referred to as " including " a specific element, it is meant to include other elements, rather than excluding other elements, unless the context clearly dictates otherwise. In addition, the limitations of " above " or " below ", respectively, based on a specific threshold value may be appropriately replaced with "

1 shows a CSMA (Collision Avoidance) / CA (Collision Avoidance) method used in wireless LAN communication.

A terminal performing wireless LAN communication carries out carrier sensing before transmitting data to check whether a channel is busy or not. If a radio signal of a predetermined intensity or more is detected, the corresponding channel is determined to be in a busy state, and the terminal delays access to the corresponding channel. This process is called Clear Channel Assessment (CCA), and the level at which the signal is detected is called the CCA threshold. If a radio signal equal to or higher than the CCA threshold value received by the terminal causes the terminal to be the receiver, the terminal processes the received radio signal. On the other hand, when a radio signal is not detected in the corresponding channel or a radio signal having an intensity lower than the CCA threshold value is detected, the channel is determined to be in an idle state.

If it is determined that the channel is empty, each terminal having data to be transmitted performs an IFS (InterFrame Space) according to the situation of each terminal, such as AIFS (Arbitration IFS), PIFS (PCF IFS) . According to the embodiment, the AIFS can be used as a substitute for the existing DIFS (DCF IFS). That is, each UE waits for a slot time equal to a random number allocated to the corresponding UE for an interval of an empty state of the channel and waits for a terminal having exhausted the slot time to access the corresponding channel . The interval during which each terminal performs the backoff procedure is referred to as a contention window period.

If a specific terminal successfully accesses the channel, the terminal can transmit data through the channel. However, if the terminal attempting to access collides with another terminal, the collided terminals are each assigned a new random number and perform the backoff procedure again. According to an embodiment, a random number newly assigned to each terminal can be determined within a range of twice the random number range previously allocated to the terminal. Meanwhile, each terminal attempts access again by performing a backoff procedure in the next contention window interval, and each terminal performs a backoff procedure from the slot time remaining in the previous contention window interval. Each terminal that performs wireless LAN communication in this manner can avoid collision of a specific channel with each other.

FIG. 2 shows an embodiment of a wireless communication method using the CCA technique.

In the wireless communication, for example, in the wireless LAN communication, it is possible to detect whether or not the channel is used through the CCA. At this time, CCA methods used include Signal Detection (SD), Energy Detection (ED), Correlation Detection (CD), and the like.

First, signal detection (CCA-SD) is a method of measuring the signal strength of a preamble of a wireless LAN (i.e., 802.11) frame. This method has a disadvantage in that it can perform stable signal detection but operate only in the initial part of a frame in which a preamble exists. According to one embodiment, signal detection may be used for CCAs for a Primary Channel in a broadband wireless LAN. Next, Energy Detection (CCA-ED) is a method of detecting the energy of all signals received above a certain threshold. This method can be used to detect signals such as Bluetooth, ZigBee, etc. that normally do not detect the preamble. The method may also be used for CCAs in a secondary channel that do not keep track of the signal. Correlation detection (CCA-CD) is a method of detecting a signal level in the middle of a wireless LAN frame, and utilizes the fact that a wireless LAN signal has a repetitive pattern of a periodic OFDM signal. That is, the correlation detection method detects the signal strength of the repeated patterns of the OFDM signal symbol after receiving the wireless LAN data for an arbitrary time.

According to the embodiment of the present invention, the access of the terminal to the channel can be controlled by using the predetermined CCA threshold value for each CCA method. In the embodiment of FIG. 2, the CCA-ED threshold value 10 represents a preset threshold value for performing energy detection, and the CCA-SD threshold value 30 represents a predetermined threshold value for performing signal detection. Also, the RX sensitivity (50) represents the minimum signal strength at which the UE can decode the radio signal. According to the embodiment, the reception sensitivity 50 may be set to a level equal to or lower than the CCA-SD threshold value 30 according to the performance and setting of the terminal. Further, the CCA-ED threshold value 10 may be set to a level higher than the CCA-SD threshold value 30. For example, the CCA-ED threshold value 10 may be set to -62 dBm, and the CCA-SD threshold value 30 may be set to -82 dBm. However, the present invention is not limited to this, and the CCA-ED threshold value 10 and the CCA-SD threshold value 30 may be set differently depending on whether they are threshold values for the main channel, .

According to the embodiment of FIG. 2, each UE measures a received signal strength indicator (RX RSSI) of a received radio signal, and based on the comparison result between the measured received signal strength and the set CCA threshold value To determine the channel state.

First, if the radio signal 350 received at a specific channel has a received signal strength RX RSSI equal to or less than the CCA-SD threshold value 30, the channel is determined to be empty. Accordingly, the received signal is not processed or protected by the terminal, and each terminal can attempt to access the channel according to the method described in FIG.

If the wireless LAN signal 330 having the received signal strength RX RSSI equal to or higher than the CCA-SD threshold value 30 is received in a specific channel, the corresponding channel is determined to be in the use state. Therefore, the terminal receiving the signal delays access to the channel. According to an exemplary embodiment, the UE can use the signal pattern of the preamble portion of the received radio signal to determine whether the corresponding signal is a WLAN signal. According to the embodiment of FIG. 2, each terminal determines that the channel is in use even when a wireless LAN signal of the same BSS as the corresponding terminal, as well as a wireless LAN signal of another BSS is received.

On the other hand, when the radio signal 310 having the received signal strength RX RSSI equal to or higher than the CCA-ED threshold value 10 is received in a specific channel, the corresponding channel is determined to be in the use state. At this time, the terminal determines that the channel is in the use state when the received signal strength of the signal is equal to or higher than the CCA-ED threshold value (10) even when a wireless signal other than the wireless LAN signal is received. Therefore, the terminal receiving the signal delays access to the channel.

FIG. 3 illustrates an example of an overlapping BSS (OBSS) environment. In FIG. 3, station 1 (STA-1) and station 2 (STA-2) are associated with AP-1 in BSS-1 operated by AP- Station 3 (STA-3) and station 4 (STA-4) are combined with AP-2. In the overlapping BSS environment of FIG. 3, at least some of the communication coverage of BSS-1 and BSS-2 are overlapped.

As shown in FIG. 3, when the STA-3 transmits upload data to the AP-2, the STA-2 of the BSS-1 located nearby can continuously interfere with the STA-2. At this time, co-channel interference (CCI) interference is generated when BSS-1 and BSS-2 use the same frequency band (for example, 2.4 GHz and 5 GHz) and the same primary channel. . In addition, the interference generated when the BSS-1 and BSS-2 use the adjacent main channel is referred to as Adjacent Channel Interference (ACI). The CCI or ACI may be received with a signal strength higher than the CCA threshold of STA-2 (e.g. CCA-SD threshold), depending on the distance between STA-2 and STA-3. If this interference is received at the STA-2 with an intensity higher than the CCA threshold, the STA-2 recognizes that the channel is in use and delays the uploading of data to the AP-1. However, since STA-2 and STA-3 are stations belonging to different BSS, if STA-2 increases CCA threshold, STA-2 and STA-3 simultaneously upload to AP-1 and AP-2 So that the effect of spatial reuse can be obtained.

On the other hand, in FIG. 3, upload data transmission of STA-3 in BSS-2 interferes with STA-4 belonging to the same BSS-2. At this time, if the CCA threshold value of STA-4 is increased to be equal to that of STA-2, STA-3 and STA-4 belonging to the same BSS transmit upload data to AP-2 simultaneously. Therefore, in order to raise the CCA threshold for arbitrary interference, it is necessary to determine whether the interference is caused by a signal belonging to the same BSS or by a signal belonging to another BSS. For this purpose, each mobile station must identify the BSS identifier of the received WLAN signal or any other type of information that can distinguish the BSS. In addition, it is desirable that the confirmation of the BSS information is performed within a short time in which the CCA process is performed.

4 shows an example of a radio frame structure used in a wireless communication system.

Particularly, FIG. 4A shows a frame structure for a frequency division duplex (FDD) used in a 3GPP LTE / LTE-A system and FIG. 4B shows a frame structure used in a 3GPP LTE / Time division duplex (TDD) frame structure.

Referring to FIG. 4, a radio frame used in the 3GPP LTE / LTE-A system has a length of 10 ms (307200 Ts) and consists of 10 equal sized subframes (SF). 10 subframes within one radio frame may be assigned respective numbers. Here, Ts represents the sampling time, and is represented by Ts = 1 / (2048 * 15 kHz). Each subframe is 1 ms long and consists of two slots. 20 slots in one radio frame can be sequentially numbered from 0 to 19. [ Each slot has a length of 0.5 ms. The time for transmitting one subframe is defined as a Transmission Time Interval (TTI). The time resource may be classified by a radio frame number (or a radio frame index), a subframe number (also referred to as a subframe number), a slot number (or a slot index), and the like.

The wireless frame may be configured differently according to the duplex mode. For example, in the FDD mode, since the downlink transmission and the uplink transmission are divided by frequency, the radio frame includes only one of the downlink subframe and the uplink subframe for a specific frequency band. In the TDD mode, since the downlink transmission and the uplink transmission are divided by time, the radio frame includes both the downlink subframe and the uplink subframe for a specific frequency band.

Table 1 illustrates the DL-UL configuration of subframes in a radio frame in TDD mode.

In Table 1, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe. The specific subframe includes three fields of Downlink Pilot Time Slot (DwPTS), Guard Period (GP), and UpPTS (Uplink Pilot Time Slot). DwPTS is a time interval reserved for downlink transmission, and UpPTS is a time interval reserved for uplink transmission. Table 2 illustrates the configuration of the singular frames.

FIG. 5 shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, FIG. 5 shows the structure of the resource grid of the 3GPP LTE / LTE-A system. There is one resource grid per antenna port. Referring to FIG. 5, a slot includes a plurality of OFDM symbols in a time domain and a plurality of resource blocks (RBs) in a frequency domain. The OFDM symbol also means one symbol period. Referring to FIG. 5, a signal transmitted in each slot may be expressed as a resource grid consisting of N ^{DL / UL} _RB * N ^RB _sc subcarriers and N ^{DL / UL} _symb OFDM symbols. have. Here, N ^DL _RB represents the number of resource blocks (RBs) in the downlink slot, and N ^UL _RB represents the number of _RBs in the UL slot. N ^DL _RB and N ^UL _RB depend on the DL transmission bandwidth and the UL transmission bandwidth, respectively. N ^DL _symb denotes the number of OFDM symbols in the downlink slot, and N ^UL _symb denotes the number of OFDM symbols in the UL slot. N ^RB _sc represents the number of subcarriers constituting one RB. The OFDM symbol may be referred to as an OFDM symbol, an SC-FDM (Single Carrier Frequency Division Multiplexing) symbol, or the like according to a multiple access scheme. The number of OFDM symbols included in one slot can be variously changed according to the channel bandwidth and the length of the cyclic prefix (CP). For example, in the case of a normal CP, one slot includes 7 OFDM symbols

In the case of an extended CP, one slot includes six OFDM symbols. Although FIG. 5 illustrates a subframe in which one slot is composed of seven OFDM symbols, embodiments of the present invention may be applied to subframes having a different number of OFDM symbols in the same manner. Referring to FIG. 5, each OFDM symbol includes N ^{DL / UL} _RB * N ^RB _sc subcarriers in the frequency domain. The type of subcarrier may be a data subcarrier for data transmission, a reference signal subcarrier for transmission of a reference signal, a null subcarrier for a guard band or a direct current (DC) ≪ / RTI > The DC component is mapped to a carrier frequency (f ₀ ) in an OFDM signal generation process or a frequency up-conversion process. The carrier frequency is also referred to as the center frequency (f _c ).

One RB is defined as N ^{DL / UL} _symb consecutive OFDM symbols in the time domain (for example, seven), and N ^RB _scrambled (e.g., twelve) consecutive subcarriers in the frequency domain . For reference, a resource composed of one OFDM symbol and one subcarrier is referred to as a resource element (RE) or tone. Therefore, one RB consists of N ^{DL / UL} _symb * N ^RB _sc resource elements. Each resource element in the resource grid can be uniquely defined by an index pair (k, 1) in one slot. k is an index assigned from 0 to N ^{DL / UL} _RB * N ^RBsc -1 in the frequency domain, and 1 is an index assigned from 0 to N ^{DL / UL} _symb -1 in the time domain.

One RB is mapped to one physical resource block (PRB) and one virtual resource block (VRB). The PRB is defined as N ^{DL / UL} _symb (e.g., 7) consecutive OFDM symbols or SC-FDM symbols in the time domain, and N ^RB _scrambled (e.g., twelve) Is defined by the subcarrier. Therefore, one PRB consists of N ^{DL / UL} _symb * N ^RB _sc resource elements. Two RBs, one in each of two slots of the subframe occupying N ^RB _sc consecutive identical subcarriers in one subframe, are called a PRB pair. The two RBs constituting the PRB pair have the same PRB number (or PRB index).

In order for the UE to receive a signal from the eNB or to transmit a signal to the eNB, the time / frequency synchronization of the UE should be synchronized with the time / frequency synchronization of the eNB. since it can determine the time and frequency parameters necessary for the UE to perform the demodulation of the DL signal and the transmission of the UL signal at the correct time, as long as it is synchronized with the eNB.

6 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.

The terminal performs an initial cell search operation such as synchronizing with a base station when power is increased or newly enters a cell (S301). To this end, the terminal receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from a base station and synchronizes with the base station and acquires information such as a cell ID have. Then, the terminal can receive the physical broadcast channel from the base station and acquire the in-cell broadcast information. Meanwhile, the UE can receive the downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE receives more detailed system information by receiving a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to the information on the PDCCH (S302).

On the other hand, if the base station is initially connected or there is no radio resource for signal transmission, the terminal can perform a random access procedure (RACH) on the base station (steps S303 to S306). To this end, the UE transmits a specific sequence through a Physical Random Access Channel (PRACH) (S303 and S305), and receives a response message for the preamble on the PDCCH and the corresponding PDSCH S304 and S306). In case of the contention-based RACH, a contention resolution procedure can be additionally performed.

The UE having performed the procedure described above transmits PDCCH / PDSCH reception (S307) and physical uplink shared channel (PUSCH) / physical uplink control channel Control Channel, PUCCH) (S308). In particular, the UE receives downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the UE, and formats are different according to the purpose of use.

Meanwhile, the control information that the UE transmits to the base station through the uplink or receives from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI) ) And the like. In the case of the 3GPP LTE system, the UE can transmit control information such as CQI / PMI / RI as described above through PUSCH and / or PUCCH.

FIG. 7 illustrates a radio frame structure for transmission of a synchronization signal (SS). Particularly, FIG. 7 illustrates a radio frame structure for transmission of a synchronization signal and a PBCH in a frequency division duplex (FDD). FIG. 7A illustrates a radio frame composed of a normal CP (normal cyclic prefix) SS and PBCH. FIG. 7 (b) shows transmission positions of the SS and the PBCH in a radio frame configured by an extended CP.

The UE obtains time and frequency synchronization with the cell when it is powered on or newly connected to the cell, and performs cell search such as detecting the physical cell identity N ^cell _ID of the cell cell search procedure. To this end, the UE receives a synchronization signal, for example, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the eNB, synchronizes with the eNB, , ID) can be obtained.

Referring to FIG. 7, the SS will be described in more detail as follows. SS is divided into PSS and SSS. PSS is used to obtain time domain synchronization and / or frequency domain synchronization such as OFDM symbol synchronization, slot synchronization, and the like. SSS is used for frame synchronization, cell group ID, and / or cell CP configuration Information). Referring to FIG. 7, the PSS and the SSS are transmitted in two OFDM symbols of each radio frame, respectively. In order to facilitate inter Radio Access Technology ("RAT") measurement, the SS considers 4.6 ms, which is the Global System for Mobile communication (GSM) frame length, in the first slot of subframe 0 and the first slot of subframe 5 Respectively. Specifically, the PSS is transmitted in the last OFDM symbol of the first slot of the subframe 0 and the last OFDM symbol of the first slot of the subframe 5, respectively, and the SSS is transmitted from the second OFDM symbol at the end of the first slot of the subframe 0, Lt; RTI ID = 0.0 > OFDM < / RTI > The boundary of the corresponding radio frame can be detected through the SSS. The PSS is transmitted in the last OFDM symbol of the slot and the SSS is transmitted in the OFDM symbol immediately before the PSS. SS's transmit diversity scheme uses only a single antenna port and is not defined in the standard. That is, a single antenna port transmission or a UE transparent transmission scheme (e.g., Precoding Vector Switching (PVS), Time Switched Diversity (TSTD), Cyclic Delay Diversity (CDD)) can be used for SS transmission diversity .

The SS can represent a total of 504 unique physical layer cell IDs through a combination of three PSSs and 168 SSs. In other words, the physical layer cell IDs are allocated to 168 physical-layer cell-identifier groups, each group including three unique identifiers, such that each physical-layer cell ID is part of only one physical-layer cell- . Thus, the physical layer cell ID _{^{N cell ID = 3N (1)}} ID + N (2) ID is a physical-layer cell - the range of 0 [identifier group to the 167 number N ⁽¹⁾ _ID and the physical-layer cell - a unique number N ⁽²⁾ _ID of 0 to 2 indicating the physical-layer identifier in the identifier group. The UE may detect the PSS to know one of the three unique physical-layer identifiers and may detect the SSS to identify one of the 168 physical layer cell IDs associated with the physical-layer identifier. A ZC (Zadoff-Chu) sequence of length 63 is defined in the frequency domain and used as the PSS.

Referring to FIG. 7, since the PSS is transmitted every 5 ms, the UE can detect that the corresponding subframe is one of the subframe 0 and the subframe 5 by detecting the PSS. However, I do not know what it is. Therefore, the UE can not recognize the boundary of the radio frame only by the PSS. That is, frame synchronization can not be obtained with only PSS. The UE detects an SSS transmitted twice in one radio frame but transmitted as a different sequence and detects the boundary of the radio frame.

8 is a diagram illustrating a control channel included in a control region of one subframe in a downlink radio frame.

Referring to FIG. 8, a subframe is composed of 14 OFDM symbols. According to the subframe setting, the first to third OFDM symbols are used as a control region and the remaining 13 to 11 OFDM symbols are used as a data region. In the figure, R1 to R4 represent a reference signal (RS) or pilot signal for antennas 0 to 3. The RS is fixed in a constant pattern in the subframe regardless of the control region and the data region. The control channel is allocated to a resource to which the RS is not allocated in the control region, and the traffic channel is also allocated to the resource to which the RS is not allocated in the data region. Control channels allocated to the control region include a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid-ARQ Indicator CHannel (PHICH), and a Physical Downlink Control Channel (PDCCH).

The PCFICH informs the UE of the number of OFDM symbols used in the PDCCH for each subframe as a physical control format indicator channel. The PCFICH is located in the first OFDM symbol and is set prior to the PHICH and PDCCH. The PCFICH is composed of four REGs (Resource Element Groups), and each REG is distributed in the control area based on the cell ID (Cell IDentity). One REG is composed of four REs (Resource Elements). RE denotes a minimum physical resource defined by one subcarrier x one OFDM symbol. The PCFICH value indicates a value of 1 to 3 or 2 to 4 depending on the bandwidth and is modulated by Quadrature Phase Shift Keying (QPSK).

The PHICH is used as a physical HARQ (Hybrid Automatic Repeat and Request) indicator channel to carry HARQ ACK / NACK for uplink transmission. That is, the PHICH indicates a channel through which DL ACK / NACK information for UL HARQ is transmitted. The PHICH consists of one REG and is cell-specific scrambled. The ACK / NACK is indicated by 1 bit and is modulated by BPSK (Binary Phase Shift Keying). The modulated ACK / NACK is spread with a spreading factor (SF) = 2 or 4. A plurality of PHICHs mapped to the same resource constitute a PHICH group. The number of PHICHs multiplexed into the PHICH group is determined by the number of spreading codes. The PHICH (group) is repetitized three times to obtain the diversity gain in the frequency domain and / or the time domain.

The PDCCH is allocated to the first n OFDM symbols of the subframe as the physical downlink control channel. Here, n is an integer of 1 or more and is indicated by the PCFICH. The PDCCH consists of one or more CCEs. The PDCCH notifies each terminal or group of terminals of information related to resource allocation of a paging channel (PCH) and a downlink-shared channel (DL-SCH), an uplink scheduling grant, and HARQ information. A paging channel (PCH) and a downlink-shared channel (DLSCH) are transmitted on the PDSCH. Therefore, the BS and the MS generally transmit and receive data via the PDSCH, except for specific control information or specific service data.

PDSCH data is transmitted to a terminal (one or a plurality of terminals), and information on how the terminals receive and decode PDSCH data is included in the PDCCH and transmitted. For example, if a particular PDCCH is CRC masked with an RNTI (Radio Network Temporary Identity) of "A ", and a DCI format called " C" Assume that information on data to be transmitted using information (e.g., transport block size, modulation scheme, coding information, etc.) is transmitted through a specific subframe. In this case, the UE in the cell monitors the PDCCH using its RNTI information, and if there is more than one UE having the "A" RNTI, the UEs receive the PDCCH, B "and" C ".

Figure 9 illustrates the configuration of a cell specific common reference signal. In particular, FIG. 9 illustrates a CRS structure for a 3GPP LTE system supporting up to four antennas.

Where k is a subcarrier index, 1 is an OFDM symbol index, p is an antenna port number, and ^{Nmax and DL} _RB represent the largest downlink bandwidth configuration, expressed as an integer multiple of N ^RB _sc .

The variables v and v _shift define positions in the frequency domain for different RSs, and v is given by

Where n _s is the slot number in the radio frame and the cell specific frequency transition is given by:

Referring to FIG. 9 and Equations 1 and 2, the current 3GPP LTE / LTE-A standard specifies that a cell-specific CRS used for demodulation and channel measurement among various RSs defined in a corresponding system is a carrier- To be transmitted over the entire downlink band. Also, in the 3GPP LTE / LTE-A system, the cell-specific CRS is used for demodulation of the downlink data signal, and thus is transmitted every antenna port for downlink transmission.

Meanwhile, the cell-specific CRS can be used not only for channel state measurement and data demodulation, but also for tracking after the UE acquires time synchronization and frequency synchronization of a carrier used for communication with the UE, It is also used for tracking.

10 shows an example of a UL subframe structure used in a wireless communication system.

Referring to FIG. 10, the UL subframe may be divided into a control domain and a data domain in the frequency domain. One or several physical uplink control channels (PUCCHs) may be assigned to the control region to carry uplink control information (UCI). One or several physical uplink shared channels (PUSCHs) may be allocated to the data area of the UL subframe to carry user data.

In the UL subframe, subcarriers far away from each other based on a DC (Direct Current) subcarrier are used as a control region. In other words, the subcarriers located at both ends of the UL transmission bandwidth are allocated for transmission of the UL control information. The DC subcarrier is a component that is left unused for signal transmission and is mapped to the carrier frequency f ₀ in the frequency up conversion process. In one subframe, the PUCCH for one UE is allocated to an RB pair belonging to resources operating at one carrier frequency, and RBs belonging to the RB pair occupy different subcarriers in two slots. The PUCCH allocated as described above is expressed as the RB pair allocated to the PUCCH is frequency hopped at the slot boundary. However, when frequency hopping is not applied, the RB pairs occupy the same subcarrier.

The PUCCH may be used to transmit the following control information.

- SR (Scheduling Request): Information used for requesting uplink UL-SCH resources. OOK (On-Off Keying) method.

- HARQ-ACK: A response to the PDCCH and / or a response to a downlink data packet (eg, codeword) on the PDSCH.

Indicates whether PDCCH or PDSCH has been successfully received. In response to a single downlink codeword, one bit of HARQACK is transmitted and two bits of HARQ-ACK are transmitted in response to two downlink codewords. The HARQ-ACK response includes positive ACK (simply ACK), negative ACK (NACK), DTX (Discontinuous Transmission) or NACK / DTX. Here, the term HARQ-ACK is mixed with HARQ ACK / NACK and ACK / NACK.

- CSI (Channel State Information): Feedback information for the downlink channel. Multiple Input Multiple Output (MIMO) -related feedback information includes RI (Rank Indicator) and PMI (Precoding Matrix Indicator).

Hereinafter, a carrier aggregation technique will be described. 11 is a conceptual diagram illustrating carrier aggregation.

Carrier aggregation is a technique in which a radio communication system uses a frequency block or a (logical sense) cell composed of uplink resources (or component carriers) and / or downlink resources (or component carriers) Which is used as a single large logical frequency band. Hereinafter, the term "component carrier" is used for the convenience of description.

Referring to FIG. 11, the total system bandwidth (System Bandwidth, System BW) has a maximum bandwidth of 100 MHz as a logical bandwidth. The total system bandwidth includes five component carriers, each of which has a bandwidth of up to 20 MHz. A component carrier comprises one or more contiguous subcarriers physically contiguous. In FIG. 11, each of the component carriers is shown to have the same bandwidth, but this is merely an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other in the frequency domain, this figure is shown in a logical concept, wherein each component carrier may physically be adjacent to or spaced from one another.

The center frequency may use different common carriers for each component carrier or common for physically contiguous component carriers. For example, assuming that all the component carriers are physically adjacent in FIG. 11, the center carrier A can be used. Further, assuming that the respective component carriers are not physically adjacent to each other, the center carrier A, the center carrier B, and the like can be used separately for each component carrier.

In this specification, the component carrier may correspond to the system band of the legacy system. By defining a component carrier based on a legacy system, it is possible to provide backward compatibility and system design in a wireless communication environment in which an evolved terminal and a legacy terminal coexist. In one example, if the LTE-A system supports carrier aggregation, each component carrier may correspond to the system band of the LTE system. In this case, the component carrier may have any of the following bandwidths: 1.25, 2.5, 5, 10, or 20 Mhz.

The frequency band used for communication with each terminal when the entire system band is expanded by carrier aggregation is defined in units of component carriers. Terminal A can use 100 MHz, which is the entire system band, and performs communication using all five component carriers. The terminals B1 to B5 can use only a 20 MHz bandwidth and perform communication using one component carrier. Terminals C ₁ and C ₂ can use a 40 MHz bandwidth and each communicate using two component carriers. The two component carriers may be logically / physically adjacent or non-contiguous. The terminal C ₁ shows a case in which two non-adjacent component carriers are used and the terminal C ₂ shows a case in which two adjacent component carriers are used.

In the LTE system, one downlink component carrier and one uplink component carrier are used, while in the LTE-A system, a plurality of component carriers can be used as shown in FIG. A combination of a downlink component carrier or a corresponding downlink component carrier and a corresponding uplink component carrier may be referred to as a cell and a corresponding relationship between a downlink component carrier and an uplink component carrier may be indicated through system information .

At this time, the scheme of scheduling the data channel by the control channel may be classified into a link carrier scheduling method and a cross carrier scheduling method.

More specifically, link carrier scheduling schedules data channels only through the particular component carrier, such as existing LTE systems that use a single component carrier, over a particular component carrier. That is, the downlink grant / uplink grant transmitted to the PDCCH region of the downlink component carrier of a specific component carrier (or specific cell) can be scheduled only for the PDSCH / PUSCH of the cell to which the corresponding downlink component carrier belongs. That is, the search space, which is an area for attempting to detect the downlink grant / uplink grant, exists in the PDCCH region of the cell where the PDSCH / PUSCH to be scheduled is located.

On the other hand, in the cross carrier scheduling, when a control channel transmitted through a primary component carrier (Primary CC) using a Carrier Indicator Field (CIF) is transmitted through the main component carrier or through another component carrier Schedules the channel. In other words, a monitored cell (Monitored Cell or Monitored CC) of the cross-carrier scheduling is set, and the downlink grant / uplink grant transmitted in the PDCCH region of the monitored cell is set to PDSCH / PUSCH of a cell set to be scheduled in the corresponding cell Scheduling. That is, a search area for a plurality of component carriers is present in a PDCCH area of a cell to be monitored. Among the plurality of cells, system information is transmitted, an initial access attempt is made, and the PCell is set by transmission of uplink control information. The PCell is a downlink main component carrier and an uplink main component carrier corresponding to the downlink main component carrier .

12 is a diagram for explaining single carrier communication and multiple carrier communication. Particularly, Fig. 12 (a) shows a subframe structure of a single carrier and Fig. 12 (b) shows a subframe structure of multiple carriers.

Referring to FIG. 12A, a general wireless communication system performs data transmission or reception (in a frequency division duplex (FDD) mode) through one DL band and one UL band corresponding thereto , A radio frame is divided into an uplink time unit and a downlink time unit in a time domain and data transmission or reception is performed through an uplink / downlink time unit (time division duplex , TDD) mode). However, in recent wireless communication systems, introduction of a carrier aggregation technique using a larger UL / DL bandwidth by collecting a plurality of UL and / or DL frequency blocks in order to use a wider frequency band is being discussed. Carrier aggregation is an orthogonal frequency division multiplexing (OFDM) scheme that performs DL or UL communication by putting a fundamental frequency band divided into a plurality of orthogonal subcarriers on one carrier frequency in that DL or UL communication is performed using a plurality of carrier frequencies division multiplexing system. Hereinafter, each of the carriers collected by carrier aggregation is referred to as a component carrier (CC). Referring to FIG. 12 (b), three 20 MHz CCs can be aggregated into the UL and the DL, respectively, and a bandwidth of 60 MHz can be supported. Each CC may be adjacent or non-adjacent to one another in the frequency domain. FIG. 12 (b) shows a case where the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetric, but the bandwidth of each CC can be set independently. Asymmetric carrier aggregation in which the number of UL CCs is different from the number of DL CCs is also possible. A DL / UL CC specific to a particular UE may be referred to as a configured serving UL / DL CC in a particular UE.

The eNB may be used to communicate with the UE by activating some or all of the serving CCs configured in the UE, or by deactivating some CCs. The eNB can change the CC to be activated / deactivated, and can change the number of CCs to be activated / deactivated. When the eNB allocates a CC available for the UE in a cell-specific or UE-specific manner, at least one of the assigned CCs is used, as long as the CC allocation for the UE is not completely reconfigured or the UE does not perform a handover. One is not disabled. A CC that is not deactivated is referred to as a primary CC (PCC), and a CC that can be freely activated / deactivated by the eNB is called a secondary CC (SCC), unless it is a full reconfiguration of the CC assignment to the UE It is called. PCC and SCC may be distinguished based on control information. For example, specific control information may be set to be transmitted and received only via a specific CC, which may be referred to as PCC and the remaining CC (s) as SCC (s).

Meanwhile, 3GPP LTE (-A) uses the concept of a cell to manage radio resources. A cell is defined as a combination of DL resources and UL resources, that is, a combination of DL CC and UL CC. A cell may consist of DL resources alone, or a combination of DL resources and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of the DL resource (or DL CC) and the carrier frequency of the UL resource (or UL CC) . For example, a combination of a DL resource and a UL resource can be indicated by linkage of System Information Block Type 2 (SIB2). Here, the carrier frequency means a center frequency of each cell or CC. In the following,

a cell operating on a frequency is referred to as a primary cell or a PCC and a cell operating on a secondary frequency (or SCC) is referred to as a secondary cell (SCell) It is called. The carrier corresponding to PCell in the downlink is referred to as a downlink primary CC (DL PCC), and the carrier corresponding to PCell in the uplink is referred to as a UL primary CC (DL PCC). SCell refers to a cell that is configurable after a Radio Resource Control (RRC) connection is established and can be used to provide additional radio resources. Depending on the capabilities of the UE, a SCell may form together with the PCell a set of serving cells for the UE. The carrier corresponding to the SCell in the downlink is referred to as DL secondary CC (DL SCC), and the carrier corresponding to the SCell in the uplink is referred to as UL secondary CC (UL SCC). For UEs that are in the RRC_CONNECTED state but no carrier aggregation is set or that do not support carrier aggregation, there is only one serving cell consisting of only PCell.

As previously mentioned, the term cell used in carrier aggregation is distinguished from the term cell, which refers to a geographical area in which a communication service is provided by a single eNB or a group of antennas. In order to distinguish between a cell designating a certain geographical area and a cell of carrier aggregation, a carrier aggregation cell is referred to as a CC and a cell in a geographical area is referred to as a cell. Quot;

In the existing LTE / LTE-A system, when multiple CCs are used together, it is assumed that the UL / DL frame time synchronization of the SCC coincides with the time synchronization of the PCC, assuming that the CCs that are not so far away in the frequency domain are clustered. However, there is a possibility that a plurality of CCs belonging to different frequency bands or spaced apart from each other in frequency, that is, a plurality of CCs having different propagation characteristics, may be gathered in the future. In this case, assuming that the time synchronization of the PCC and the time synchronization of the SCC are the same as in the conventional case, the synchronization of the DL / UL signal of the SCC may be seriously adversely affected.

Meanwhile, in the case of the LCT CC, among the radio resources operating in the LCT CC, radio resources available for transmission / reception of physical uplink / downlink channels and radio resources available for transmission / reception of physical uplink / The resources, as described above, are predetermined. In other words, the LCT CC is not configured to carry physical channels / signals through arbitrary time frequency in arbitrary time resources, but may be configured to transmit the physical channel / Signal should be configured to carry. For example, the physical downlink control channels may be configured only in the first OFDM symbol (s) of the OFDM symbols in the DL subframe, and the PDSCH may include the first OFDM symbol (s) that are likely to be mapped physical downlink control channels. Lt; / RTI > As another example, the CRS (s) corresponding to the antenna port (s) of the eNB are transmitted every subframe in the REs shown in Fig. 9 over the entire band regardless of the DL BW of the eNB. Therefore, when the number of antenna ports of the eNB is 1, the REs indicated by '0' in FIG. 9 are '0', '1', '2' and ' 3 'can not be used for other downlink signal transmission. In addition, there are various constraints on the composition of the LCT CC, and these constraints are greatly increased as the communication system develops. Some of these constraints arise because of the level of communication technology at the time the constraint is created, and there are some constraints that are unnecessary as communication technology develops, and constraints of existing and new technologies for the same purpose It may be present at the same time. As the constraints become so large, the constraints introduced for the development of the communication system are making the wireless resources of the CC ineffective. Therefore, the introduction of NCT CC, which can be constructed according to the simplified constraints rather than the existing constraints, is free from the constraints that are unnecessary according to the development of the communication technology. Since the NCT CC is not constructed according to the constraints of the existing system, it can not be recognized by the UE implemented according to the existing system. Hereinafter, UEs which are implemented according to the existing system and can not support NCT CC are called legacy UEs, and UEs implemented to support NCT CCs are called NCT UEs.

It is considered that NCT CC will be used as SCC in LTE-A system in the future. Since the NCT CC does not consider use by the legacy UE, the legacy UE does not need to perform cell search, cell selection, cell reselection, etc. in the NCT CC. If the NCT CC is not used as a PCC and the NCT CC is used only as an SCC, unnecessary constraints on the SCC can be reduced compared to an existing LCT CC that can be used as a PCC, enabling more efficient use of the CC. However, the time / frequency synchronization of the NCT CC may not coincide with the synchronization of the PCC. Even if the time / frequency synchronization of the NCT CC is obtained once, the time / frequency synchronization may be changed according to the change of the communication environment. An RS in which time synchronization and / or frequency synchronization can be used for tracking is required. An RS is also needed to allow the UE to detect the NCT CC in the neighbor cell search process. CRS can be used for purposes such as time / frequency synchronization of NCT CC and neighbor cell search using NCT CC. The CRS may be configured in the NCT CC in the same manner as in the existing LTE / LTE-A system shown in FIG. 9 and may have less density on the time axis or frequency axis than the conventional LTE / LTE- It may be configured in the NCT CC.

In the present invention, it is proposed that the CRS on the NCT CC is configured to have a lower density on the time axis than the CRS on the LCT CC of the existing LTE / LTE-A system. Accordingly, in the present invention, the NCT CC includes a constraint condition that the CRS is configured in the corresponding CC for every DL subframe, a constraint condition that the CRS is configured in the CC for each antenna port of the eNB, a predetermined number of OFDM It may not satisfy at least one of the constraint conditions that the symbol should be reserved for transmission of the control channel such as the PDCCH over the frequency band of the corresponding CC. For example, on the NCT CC, a CRS may be configured for every predetermined number (> 1) of subframes, not every subframe. Or, on the NCT CC, only the CRS for one antenna port (e.g., antenna port 0) can be configured regardless of the number of antenna ports of the eNB. The CRS of the present invention may not be used for demodulating data unlike the existing CRS shown in FIG. Therefore, instead of the existing CRS used for channel state measurement and demodulation, a tracking RS is newly defined for tracking of time synchronization and / or frequency synchronization, and the tracking RS is added to some subframes and / or some frequency resources on the NCT CC Lt; / RTI > Alternatively, the PDSCH may be configured in the leading OFDM symbols on the NCT CC, the PDCCH may be configured in the existing PDSCH region other than the initial OFDM symbols, or the PDCCH may be configured using some frequency resources. Hereinafter, unlike the existing LTE / LTE-A system, unlike the existing LTE / LTE-A system, the RSs transmitted in some subframes can be used in common by any UE regardless of the name, such as time synchronization and / or frequency synchronization of the NCT CC, RS (common RS, CRS).

13 is a diagram showing an example in which a cross carrier scheduling technique is applied. In particular, in FIG. 13, the number of allocated cells (or component carriers or component carriers) is three and the cross carrier scheduling technique is performed using CIF as described above. Here, it is assumed that the downlink cell # 0 is a downlink main component carrier (i.e., a primary cell, PCell) and the remaining component carriers # 1 and # 2 are subsidiary components (i.e., a secondary cell, SCell).

In the present invention, an effective management method of uplink resources for a main component carrier (primary component carrier, primary cell or PCell) or a subsidiary component carrier (secondary component carrier or secondary cell or SCell) during a carrier aggregation operation I suggest. Hereinafter, the case where the terminal operates by merging two component carriers is explained, but it is obvious that the present invention can also be applied to the case of merging three or more component carriers.

14 is a diagram for explaining the LAA environment.

As shown in FIG. 14, a service environment in which U-LTE or LAA, which is the LTE technology 11 in the existing authorization band and the LTE technology 12 in the unlicensed band which is actively discussed in recent years, have.

If a service environment utilizing the LTE-Unlicensed frequency band is established, there is no need to pay additional costs in order to secure frequency licenses from the viewpoint of the telecommunication service provider. In addition, interference between communication carriers and 3G / And integration problems with the communication network can be easily solved.

Further, a technique such as Carrier Aggregation can integrate the LTE technology 11 in the licensed band and the LTE technology 12 in the unlicensed band, and can contribute to expanding the network capacity in the future. Also, in an environment where asymmetric traffic having more downlink data is generated than uplink data, such an integrated technique can be helpful in providing optimized LTE services according to various needs and environments.

In order to efficiently solve the interference problem in the unlicensed band, it is necessary to introduce a separate coexistence mechanism with other communication systems by reducing the output to minimize the influence on other communication systems used in the unlicensed band Low-power LTE technology is proposed.

In addition, algorithms such as Listen-Before-Talk (LBT) and Dynamic Frequency Selection (DFS), which can detect the output of a base station or the like used by other communication providers and adaptively select a block corresponding to the used frequency, There is also a move to introduce additional technologies.

Since most devices operating in the unlicensed band operate on an LBT basis, the devices perform a clear channel estimation technique that senses the channel before transmitting data.

In case of LTE communication in the unlicensed band, equipment communicating in the unlicensed band with Wi-Fi technology can not demodulate LTE-Unlicensed message or data, judge LTE-Unlicensed message or data as energy, It is possible to perform the interference avoiding operation. That is, if the energy corresponding to the LTE-Unlicensed message or data is less than minus (-) 62 dbm, the Wi-Fi devices can communicate without ignoring the message or data. As a result, in the unlicensed band, a terminal that performs LTE communication may frequently receive interference by Wi-Fi equipment.

Therefore, in order to effectively implement LTE-Unlicensed technology and services, it is necessary to allocate or reserve a specific frequency band for a specific time. However, as described above, there is a problem that it is difficult to efficiently use the LTE-Unlicensed service because the peripheral devices communicating through the unlicensed radio attempt to access based on the energy detection technique.

15 is a diagram illustrating a deployment scenario of a terminal and a base station in an LAA service environment.

In the frequency band targeted by the LAA service environment, the wireless communication distance is not long due to the high frequency characteristics. In consideration of this, the deployment scenario between the terminal and the base station in the environment where the existing LTE-licensed service and the LAA service coexist is the overlay model shown on the left side of FIG. 15 and the overlay model shown in the right side of FIG. or a co-located model.

In the case of the overlay model shown on the left side of FIG. 15, the macro eNB performs wireless communication with the X terminal and the X 'terminal in the macro area 32 using a licensed carrier, and a plurality of RRHs and an X2 interface Lt; / RTI > Each RRH may perform wireless communication with an X terminal or an X 'terminal in a certain area 31 using an unlicensed carrier. In this case, there is no mutual interference between the macro eNB and the RRH. However, in order to use the LAA service as an auxiliary downlink channel of the LTE-licensed service through carrier aggregation, an X2 interface between the macro eNB and the RRH A fast data exchange should be made.

In the case of the co-located model shown on the right-hand side of FIG. 15, the pico / femto eNB can perform wireless communication with the Y terminal simultaneously using the authorized carrier and the unauthorized carrier. However, the use of the LTE service and the LAA service together is considered in the downlink data transmission. In this case, coverage for LTE service and coverage for LAA service may differ depending on frequency band, transmission power, and the like.

A terminal according to an embodiment of the present invention can be implemented by various types of wireless communication devices or computing devices that are guaranteed to be portable and mobility.

The base station according to the embodiment of the present invention controls and manages a cell (for example, a macro cell, a femtocell, a picocell, etc.) corresponding to a service area and transmits a signal, channel designation, channel monitoring, Can be performed.

16 is a block diagram showing a configuration of a terminal and a base station according to an embodiment of the present invention.

As shown, a terminal 100 according to an embodiment of the present invention may include a processor 110, a communication module 120, a memory 130, a user interface unit 140, and a display unit 150 have.

First, the processor 110 may execute various commands or programs, and may process data inside the terminal 100. [ In addition, the processor 100 can control the entire operation including each unit of the terminal 100, and can control data transmission / reception between the units.

Next, the communication module 120 may be an integrated module that performs mobile communication using a mobile communication network and wireless LAN connection using a wireless LAN. To this end, the communication module 120 may include a plurality of network interface cards such as the cellular communication interface cards 121 and 122 and the wireless LAN interface card 123, either internally or externally. In FIG. 16, the communication module 120 is shown as an integrated integrated module, but each network interface card may be independently arranged according to the circuit configuration or use, unlike FIG.

The cellular communication interface card 121 according to the first frequency band transmits and receives a radio signal with at least one of the base station 200, the external device, and the server using the mobile communication network, Band cellular communication service. Here, the wireless signal may include various types of data or information such as a voice call signal, a video call signal, or a text / multimedia message.

According to an embodiment of the present invention, the cellular communication interface card 121 by the first frequency band may include at least one NIC module using the LTE-Licensed frequency band. According to an embodiment of the present invention, at least one NIC module performs cellular communication with at least one of the base station 200, the external device, and the server independently in accordance with the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module . The cellular communication interface card 121 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

The cellular communication interface card 122 in the second frequency band transmits and receives a radio signal to and from a base station 200, an external device, and a server using a mobile communication network, Band cellular communication service. According to an embodiment of the present invention, the cellular communication interface card 122 by the second frequency band may include at least one NIC module using the LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module performs cellular communication with at least one of the base station 200, the external device, and the server independently in accordance with the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module . The cellular communication interface card 122 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

The wireless LAN interface card 123 according to the second frequency band transmits and receives a radio signal to at least one of the base station 200, the external device, and the server through the wireless LAN connection, Band wireless LAN service. According to an embodiment of the present invention, the wireless LAN interface card 123 according to the second frequency band may include at least one NIC module using the wireless LAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module performs wireless communication with at least one of the base station 200, the external device, and the server independently in accordance with a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module . The wireless LAN interface card 123 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

According to an embodiment of the present invention, the processor 110 transmits information on whether or not the wireless LAN communication service of the second frequency band is available through the cellular communication channel of the first frequency band with the base station 200, Information on the period of time. Here, the information on the predetermined period is information set for receiving the downlink data from the base station 200 through the cellular communication channel of the second frequency band.

In addition, according to an embodiment of the present invention, since the base station 200 supports a wireless LAN communication service, the processor 110 can receive a predetermined signal from the base station 200 through a wireless LAN communication channel of a second frequency band And receives the base station coexistence message including information on the period.

In addition, according to an embodiment of the present invention, the processor 110 may be configured to transmit, in response to the received base station coexistence message, The terminal transmits a terminal coexistence message including information on a predetermined period according to a standard or protocol specified in the wireless LAN communication service of the second frequency band.

Also, according to an embodiment of the present invention, the processor 110 receives downlink data from the base station 200 for a predetermined period through a cellular communication channel of a second frequency band.

Next, the memory 130 stores a control program used in the terminal 100 and various data corresponding thereto. The control program may include a predetermined program required for the terminal 100 to perform wireless communication with at least one of the base station 200, the external device, and the server.

Next, the user interface 140 includes various types of input / output means provided in the terminal 100. That is, the user interface 140 can receive user input using various input means, and the processor 110 can control the terminal 100 based on the received user input. In addition, the user interface 140 may perform output based on instructions of the processor 110 using various output means.

Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects such as a content executed by the processor 110 or a user interface based on a control command of the processor 110. [

16, a base station 200 according to an embodiment of the present invention may include a processor 210, a communication module 220, and a memory 230. In addition,

First, the processor 210 may execute various commands or programs and may process data within the base station 200. In addition, the processor 210 can control the entire operation including each unit of the base station 200, and can control data transmission / reception between the units.

Next, the communication module 220 may be an integrated module for performing mobile communication using a mobile communication network and wireless LAN connection using a wireless LAN, such as the communication module 120 of the terminal 100 described above. To this end, the communication module 120 may include a plurality of network interface cards, such as the cellular communication interface cards 221 and 222 and the wireless LAN interface card 223, either internally or externally. In Fig. 16, the communication module 220 is shown as an integrated integration module, but each network interface card may be independently arranged according to the circuit configuration or use, unlike Fig.

The cellular communication interface card 221 according to the first frequency band transmits and receives a radio signal to at least one of the terminal 100, the external device, and the server using the mobile communication network, And provides cellular communication service by one frequency band. Here, the wireless signal may include various types of data or information such as a voice call signal, a video call signal, or a text / multimedia message.

According to an embodiment of the present invention, the cellular communication interface card 221 by the first frequency band may include at least one NIC module using the LTE-Licensed frequency band. According to an embodiment of the present invention, the at least one NIC module can perform cellular communication with at least one of the terminal 100, the external device, and the server independently according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module. Can be performed. The cellular communication interface card 221 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200.

The cellular communication interface card 222 according to the second frequency band transmits and receives a radio signal to at least one of the terminal 100, the external device, and the server using the mobile communication network, And provides a cellular communication service by two frequency bands. According to an embodiment of the present invention, the cellular communication interface card 222 by the second frequency band may include at least one NIC module using the LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, the at least one NIC module can perform cellular communication with at least one of the terminal 100, the external device, and the server independently according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module. Can be performed. The cellular communication interface card 222 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200. [

The wireless LAN interface card 223 according to the second frequency band transmits and receives a wireless signal to at least one of the terminal 100, the external device, and the server through the wireless LAN connection, 2 frequency band. According to an embodiment of the present invention, the wireless LAN interface card 223 according to the second frequency band may include at least one NIC module using the wireless LAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module independently communicates with at least one of the terminal 100, the external device, and the server in accordance with a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module Can be performed. The wireless LAN interface card 223 can operate only one NIC module at a time or operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200. [

According to an embodiment of the present invention, the processor 210 transmits information on whether or not the wireless LAN communication service of the second frequency band is available through the cellular communication channel of the first frequency band with the terminal 100, Information on the period of time. Here, the information on the predetermined period is information set for transmitting the downlink data to the terminal 100 through the cellular communication channel of the second frequency band.

In addition, according to an embodiment of the present invention, the processor 210 may be a peripheral terminal capable of communicating with the base station 200 through the terminal 100 and the wireless LAN communication service of the second frequency band, And transmits the base station coexistence message including information on a predetermined period according to a standard or protocol defined in the wireless LAN communication service to the terminal 100 for a predetermined period on the cellular communication channel of the second frequency band, .

In addition, according to an embodiment of the present invention, since the terminal 100 supports the wireless LAN communication service, the processor 210 transmits the base station coexistence message Lt; RTI ID = 0.0 > coexistence < / RTI > Here, the terminal coexistence message includes information on a predetermined period.

The terminal 100 and the base station 200 shown in FIG. 16 are block diagrams according to an embodiment of the present invention. Blocks that are separately displayed are logically distinguished from elements of a device. Thus, the elements of the device described above can be mounted as one chip or as a plurality of chips depending on the design of the device. In addition, in the embodiment of the present invention, some components of the terminal 100, such as the user interface 140 and the display unit 150, may be optionally provided in the terminal 100. In addition, in the embodiment of the present invention, the user interface 140, the display unit 150, and the like may be additionally provided to the base station 200 as needed.

Below is a description of the LBT method in Licensed Assisted Access considered in LTE.

First, the channel access method on the license-exempted band can be classified into four methods.

- Category 1: No LBT

- Tx. LBT procedure by entity is not performed.

- Category 2: LBT  without random back-off

- Tx. The time interval during which the channel is idle is determined before the entity transmits.

- Category 3: LBT  with random back-off with a contention window of fixed size

- A LBT method that performs a random back-off with a contention window with a fixed size. The Tx entity has a random N value in one contention window, sets the contention window by the minimum and maximum values of N , The contention window size is fixed. A random N value is used in the LBT procedure to determine the time interval during which the channel is idle before the Tx entity transmits on the channel.

- Category 4: LBT  with random back-off with a contention window of variable size

- A LBT method that performs a random back-off with a contention window with a variable size. The Tx entity has a random N value in one contention window, sets the contention window by the minimum and maximum values of N , and Tx An entity can change its contention window size when generating a random N value. A random N value is used in the LBT procedure to determine the time interval during which the channel is idle before the Tx entity transmits on the channel.

The category 4 LBT considered in licensed assisted access (LAA) to ensure fair channel access with WiFi is:

The contention window size (CWS) in the LAA is variable as a dynamic variable backoff or a semi-static backoff between the X and Y ECCA slots. More specifically:

- An example of a change in CW may be an exponential back-off.

The X and Y values are configurable parameters.

- Two methods can be considered to adjust CW for PDSCH. First, there may be a method of adjusting the CW based on the feedback / report (for example, HARQ Ack / Nack) of the UE. Next, there may be a method of adjusting the CW based on the sensing of the eNB.

The minimum extended clear channel assessment (CCA) is considered to be less than 20us.

Initial CCA (ICCA) can be configurable with values comparable to defer periods such as DIFS or AIFS used in WiFi.

When the ECCA count-dwon is interrupted, one defer period is applied after the channel becomes idle, and does not perform ECCA count down during the defer period.

The Defer period is configurable and can be configured to match the defer period of WiFi, eg DIFS or AIFS.

An Initial CCA is performed to transmit the DL transmission burst when the eNB fails to complete transmission of a signal or channel even though the random backoff counter reaches zero in the backoff procedure

The adaptability of the energy detection reference value can be applied to the above LBT procedure. The defer period is defined as the minimum time that one node must wait after the channel becomes idle before transmission. That is, if the channel is idle for a time interval that is not less than the defer interval, one node performs the transmission.

A flow chart for explaining the LBT procedure is shown in FIGS. 17 and 18. FIG.

Below is a description of parameter setting and additional LBT catetory 4 operation during Listen before Talk (LBT) operation in LAA.

For LBT operation in LAA, the slot size of ECCA is 9 μs, and the actual sensing time is at least 4 μs.

For operation in the LBT category 4 method for PDSCH, one defer period consists of 16μs duration and n consecutive CCA slots. Here, n denotes a positive integer, CCA slot duration is 9 μs, and the number of slots in the defer period can be set differently according to different QoS classes. The backoff counter does not count down during the 16 μs duration at the beginning of the defer period, and the back off counter can be decremented by 1 at the end of the defer period when all n slots are observed as idle. If the backoff counter reaches zero after decrementing, the node continues the ECCA procedure by performing a CCA check during at least one slot without immediately transmitting immediately. The defer period may also be interrupted if the channel is observed to be busy at some other interval.

Hereinafter, a channel access procedure for transmitting the PDSCH will be further described.

The eNB may transmit a transmisson containing the PDSCH on the channel on which the LAA Scell (s) transmission is performed after the channel is idle for defer duration (Td) and after the random backoff counter (N) has become zero . Where counter N is adjusted by sensing the channel for additional slot duration (s) according to the procedure below.

1) N = Ninit. Ninit is a random number from a uniformly distributed value between 0 and CWp.

2) If N> 0 and the eNB chooses to decrease the counter, set N = N-1.

3) It senses the channel during one additional slot duration, and if it idle during that additional slot duration, go to step 4), otherwise go to step 5).

4) If N = 0, stop; otherwise go to step 2).

5) It senses the channel during one additional defer duration (Td) interval.

6) If the channel is sensed as idle during slot intervals of the additional defer duration (Td), go to step 2), otherwise go to step 5).

If the eNB has not transmitted a transmission including PDSCH on the channel on which the LAA Scell (s) transmission is performed after step 4 in the previous step, the eNB will notify the UE that at least the channel idle during the slot periods of the additional defer duration (Td) It is possible to transmit the transmission including the PDSCH in the corresponding channel.

Here, the defer duration (Td) is composed of consecutive slot durations that are directly followed by 16us (Tf), each slot duration (Tsi) is 9us, and Tf is one idle slot duration Tsi at the beginning of Tf .

The mp value is set according to the channel access priority class according to table X-1 below.

Table X-1. Channel Access Priority Class

If the eNB senses a channel for one slot duration and the power detected by the eNB for at least 4us within that slot duration is less than or equal to X_Threshold, then one slot duration (Tsi) is considered idle. Otherwise, the slot duration (Tsi) is considered busy.

조건을 만족하도록 Contention window(CW)는 설정되며, CWmin,p와 CWmax,p는 random backoff counter N에 관계된 절차인 단계 1) 동안 선택된다. 그리고 CW의 조정방법에 대해서는 아래 발명의 상세 내용에 따로 설명한다. As for the setting of the Contention window, according to the CWmin, p and CWmax, p set according to the channel access priority class

The contention window (CW) is set to satisfy the condition, and CWmin, p and CWmax, p are selected during step 1), which is a procedure related to the random backoff counter N. The method of adjusting the CW will be described in detail in the following description of the invention.

The adjustment of X_Threshold is based on case and regulation coexisting with other technology as shown in table Y-1 below, and the energy detection threshold (X_Threshold) is set by distinguishing the case where Wi-Fi is absent.

Table Y-1. Energy Detection Thershold adaptation rule

The value of Tmax in Table Y-1 is shown in the following equation.

In addition, T_mcot, p is set according to the channel access priority class according to Table X-1, and the eNB does not continuously transmit T_mcot, p over a single channel on which LAA Scell (s) transmission is performed Should be. For the priority class p = 3 and p = 4, we set T_mcot, p = 10ms for the case where it is possible to guarantee the absence of other technology using the license term based on the long term at the regulation level. T_mcot, p = 8ms.

The present invention relates to a method for accessing a channel at the time of carrier sensing and is a method for adaptively adjusting a contention window size (hereinafter referred to as CWS).

There is a method of adjusting the CWS based on the UE feedback transmitted from the UE as a method of adjusting the CWS. In the following description of the present invention, a method of adaptively adjusting CWS according to ACK / NACK / DTX considered as HARQ-ACK response as UE feedback can be considered as feedback of the UE in consideration of HARQ-ACK response and CQI / PMI / Will be described.

The following method can be considered as one embodiment of a method of adjusting CWS based on an ACK / NACK of an HARQ-ACK response in a method of adaptively adjusting CWS in the present invention.

First, in case of contention window size (CWS) adjustment based on HARQ-ACKs, sets of HARQ-ACK feedback values to be considered are defined as follows. The set of HARQ-ACKs feedback values considered for CWS coordination is decoded at the time the CWS is determined and corresponds to the available HARQ-ACKs.

The following methods can be considered as the method of adjusting the CWS based on the set of the HARQ-ACK feedback values. For the options 1, 2, 3 and alt 1, 2 and 3, the corresponding combination is considered as a method of adjusting the CWS .

Option 1: Increase the contention window size (CWS) if all HARQ-ACK feedback values for a single subframe are NACK; otherwise, reset the CWS to the minimum value. Where a single subframe may be the first or last DL subframe of the last DL transmission burst. In calculating the set of the HARQ-ACK feedback value, the HARQ-ACK feedback may be all the available subframes of the HARQ-ACK feedback of the last available DL transmission burst.

Option 2: Increase the contention window size (CWS) if at least one of the HARQ-ACK feedback values for the subframe is NACK; otherwise, reset the CWS to the minimum value. Where a single subframe may be the first or last DL subframe of the last DL transmission burst. In calculating the set of the HARQ-ACK feedback value, the HARQ-ACK feedback may be all the available subframes of the HARQ-ACK feedback of the last available DL transmission burst.

Option 3: Increase CWS when the NACK of the HARQ-ACK feedback value is at least Z% within the predetermined window, otherwise reset CWS to the minimum value. Where a single subframe may be the first or last DL subframe of the last DL transmission burst. In calculating the set of the HARQ-ACK feedback value, the HARQ-ACK feedback may be all the available subframes of the HARQ-ACK feedback of the last available DL transmission burst.

In addition, if at least one of the following conditions is satisfied, the CWS is reset to the minimum value.

- Alt 1: where maximum CWS is used for K consecutive eCCAs for transmission, where K may be 1, 2, or 3. The K choices may also be selected by the base station, and the values may be selected within the values {1, ..., 8}.

- Alt 2: No DL transmission by eNB during at least T interval

In an exemplary embodiment of the present invention, a reference time window for setting a reference HARQ-ACK feedback value for increasing CWS may be a regular subframe or a partial subframe in a single subframe of the last DL transmission burst. In the case of a partial subframe, since the number of UEs to which a base station can be served may be limited, a set of HARQ-ACK feedback values is set based on a HARQ-ACK feedback value of a UE (s) corresponding to a regular subframe, Thereby allowing the base station to perform efficient coordination of the CWS due to collision or interference.

The method that can be applied when increasing CWS in option-1, option-2, and option-3 is to set CWS to increase to double, or to increase it exponentially between CW_min and CW_max, or to maximize CWS Can all be considered.

As another embodiment of the present invention, a method of adjusting CWS in consideration of not only ACK and NACK but also DTX as HARQ-ACK response transmitted from a terminal when the CWS is adjusted will be described.

First, a DL or UL transmission of a carrier of each license-exempt band is performed through a control channel transmitted on each license-exempt band carrier, for example, a PDCCH and an EPDCCH during self-carrier scheduling, The ACK / NACK / DTX used in the current LTE may exist as the HARQ feedback that the UE can transmit. The following is a description of a procedure of HARQ-ACK in an FDD having one or more serving cells, in which a HARQ-ACK is transmitted in a PUCCH format 1b with channel selection as a PUCCH format transmitted in PCell. The following table is an example to illustrate that there is a mechanism to allow DTX to be transmitted or DTX to be recognized by the base station as HARQ-ACK respose created in the standard 3GPP TS36.213v12.6.0. Here, DTX is one of methods for the UE to notify the BS when the UE fails to decode the PDCCH / EPDCCH despite transmitting PDCCH / EPDCCH, which is a control channel including scheduling information, to the UE.

3GPP TS36.213v12.6.0

10.1.2.2 FDD HARQ-ACK procedures for more than one configured serving cell

...

10.1.2.2.1 PUCCH format 1b with channel selection HARQ-ACK procedure

...

Table 10.1.2.2.1-1: Mapping of Transport Block and Serving Cell to HARQ-ACK (j) for PUCCH format 1b HARQ-ACK channel selection

Table 10.1.2.2.1-3: Transmission of Format 1b HARQ-ACK channel selection for A = 2

Table 10.1.2.2.1-4: Transmission of Format 1b HARQ-ACK channel selection for A = 3

Table 10.1.2.2.1-5: Transmission of Format 1b HARQ-ACK channel selection for A = 4

First, in the case of contention window size (CWS) adjustment based on HARQ-ACKs, sets of HARQ-ACK feedback values to be considered can be defined as follows. The set of HARQ-ACKs feedback values considered for CWS coordination is decoded at the time the CWS is determined and corresponds to the available HARQ-ACKs.

A-1, A-2, A-3, A-4 and B-1, B-2, and A-4 can be considered as methods for adjusting CWS based on a set of HARQ- For B-3, the combination can be considered as a way of adjusting the CWS.

Method A-1: All HARQ - ACK for Single / multiple subframes If the feedback value is all NACK or all HARQ - ACK The feedback value is If considered as DTX or all HARQ - ACK The feedback value is Increases the contention window size (CWS) if NACK / DTX , otherwise resets CWS to the minimum value. Here, a single subframe may be the first or last DL subframe of the last DL transmission burst. In case of multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmission burst, and a multiple subframe . For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

Method A-2: Increase the contention window size (CWS) if at least one of the HARQ-ACK feedback values for the single / multiple subframe is NACK or DTX , otherwise, reset the CWS to the minimum value. Here, a single subframe may be the first or last DL subframe of the last DL transmission burst. In case of multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmission burst, and a multiple subframe . For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

Method A-3: NACK of the HARQ-ACK feedback value within the predetermined window or When DTX is that in the case of at least% Z, and to increase the CWS, otherwise it is reset to the minimum value of CWS. The window to be set here may be a single subframe, which may be the first or last DL subframe of the last DL transmission burst. If it is set to multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmsision burst, Or may be a multiple subframe. For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Or a predetermined window can be set by the base station. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

Method A-4: All HARQ - ACK for Single / multiple subframes The feedback value is When considered as DTX is to be considered a base station or decoding of a transmission control channel PDCCH / EPDCCH even not received by the terminal by the collision failed the PDCCH / EPDCCH decoding of by the interference of the transmission from the other node the CWS Here, as a method of increasing CWS, a method of increasing CWS to double, or exponentially increasing CW_min and CW_max, or increasing CWS to a maximum value may all be considered. Otherwise, all HARQ - ACKs The feedback value is If not considered DTX , increase CWS or reset CWS to the minimum value according to the method shown in Methods A-1, A-2, A-3. Here, a single subframe may be the first or last DL subframe of the last DL transmission burst. In case of multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmission burst, and a multiple subframe . For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

In addition, if at least one of the following conditions is satisfied, the CWS is reset to the minimum value.

Method B-1: Where maximum CWS is used for K consecutive eCCAs for transmission, where K may be 1, 2, or 3. The K choices may also be selected by the base station, and the values may be selected within the values {1, ..., 8}.

Method B-2: If there is no DL transmission by the eNB during at least T interval

Method B-3: where maximun HARQ retransimssion is used during K consecutive eCCAs, where K may be 1, 2, or 3. The K choices may also be selected by the base station, and the values may be selected within the values {1, ..., 8}.

The methods that can be applied when increasing CWS in methods A-1, A-2, A-3, and A-4 include setting CWS to increase to double, exponentially increasing CW_min to CW_max, To a maximum value can all be considered.

Next, in cross-carrier scheduling,

If DL transmission to unlicensed carriers is due to cross-carrier scheduling from another license-exempt band, unlicensed carrier, CWS adjustment is performed using the same method as in self-carrier scheduling. Since the control channel is transmitted on unlicensed carriers as in self-carrier scheduling, the self-carrier scheduling and HARQ-ACK response (ACK, NACK, DTX) to be.

If DL transmission to unlicensed carriers is due to cross-carrier scheduling from the licensed band, ie, licensed carrier, transmission of the PDCCH / EPDCCH to perform DL transmission is transmitted from the license band. In case of DTX feedback for recognizing the terminal as a HARQ response of the terminal, it is used to determine the decoding state of the terminal for the control channel transmitted on the license band. Therefore, adaptive control of the CWS considered as a method for accessing the channel in the license- It may not help to do so. Therefore, when cross-scheduling from the license band, the CWS adjustment method considering DTX is not used as the HARQ-ACK response from the terminal, and only ACK and NACK are used as the HARQ-ACK reponse for DL transmission on the license- Based on which the method of adjusting the CWS can be used.

Considering ACK, NACK and ACK, NACK, and DTX as HARQ-ACK response in the present invention, DL transmission bursts transmitted from a base station are scheduled for a single UE and scheduling for multiple UEs The method of adjusting CWS considering feedback from one UE and the method of adjusting CWS considering feeback from multiple UEs can all be considered.

The HARQ-ACK response transmitted from the UE is set to be transmitted through the PUCCH or PUSCH on the PCell of the license band. Of course, the present invention can be applied to the transmission of the HARQ-ACK response through the PUCCH or PUSCH on the unlicensed band in the case where the uplink transmission on the license-exempt band is allowed.

The present invention relates to a method for an efficient channel access procedure through modification of the channel access procedure described above.

The following embodiment of the present invention will be described as an embodiment for performing an efficient channel access procedure through modification of the channel access procedure for transmitting the PDSCH described above.

When the Ninit value of the random backoff counter is 1 and the Ninit value of the random backoff counter is 0, when the channel access procedure for transmitting the PDSCH described above is followed, the number of slots sensing the channel is the same Can be set. If the channel is idle at more than one duration (Td) and one slot duration (Tsi), the defer duration and the random backoff counter The channel sensing interval is set according to the intention of the Ninit value to sense the channel during one slot duration by the extraction value Ninit = 1, but when the Ninit value is 0, the channel access procedure for transmitting the PDSCH described above is performed If the channel idle at more than the defer duration (Td) and zero slot duration (Tsi), the intention of the Ninit value to sense the channel during the slot duration of 0 by Ninit = 0, (Td) and one slot duration (Tsi) by sensing the channel for one slot duration according to step 3) and the channel sensing interval is set so that it does not fit the intention of the Ninit value.

In the present invention, when the N value is 0, if the slot durations of the defer duration (Td) are idle, it is possible to instantaneously transmit the transmission including the PDSCH in the channel where the LAA Scell (s) transmission is performed, The channel access procedure is performed by differentiating the number of slot durations (Tsi) sensed in the case of setting Y (Y + 1) and Y (Ninit). (Y + 1) is selected as the Ninit value when the channel on the LAA Scell (s) to be transmitted is idle, channel sensing (Y + 1) is performed for defer duration (Td) + And transmits the transmission (s) including the PDSCH. When Y is extracted as the Ninit value, channel sensing is performed during defer duration (Td) + Y slot duration (Tsi) To transmit the transmitted transmission (s). Where Y can be zero and can be a natural number greater than or equal to zero.

FIG. 19 illustrates an embodiment of the present invention as described above. As an example of a case where a channel is idle, channel priority class 3 is used as a defer duration, and 19- (a) and channel priority Figure 3 shows the case of 19- (b) using class 3 and extracting Ninit = 0.

As another embodiment, when the channel is busy while decreasing the N value to perform the set random backoff, if N is set to a value set by the Ninit value and then it is determined that the channel is busy, (Td), and when the channel is continuously busy during the Td interval, the channel sensing is continuously performed for Td, and is set in units of Tsi according to the N value for random backoff The number of total idle slots should be set to the number of Tsi according to Ninit.

If the Ninit value of the random backoff counter is 2 and the Ninit value of the random backoff counter is 1, if the channel access procedure for transmitting the PDSCH described above is followed, the number of slots sensing the channel is the same Can be set. If the channel is idle at defer duration (Td) and busy at one of the two slot durations (Tsi), then 2 defer duration The channel sensing interval is set according to the intention of the Ninit value to detect the channel during the 2 slot duration (Tsi) interval by the extraction value Ninit = 2 of the random backoff counter. However, when 1 is taken as the Ninit value, If the channel is idle at defer duration (Td) and busy at one slot duration (Tsi), then one deinterleaver with two defer durations and an extracted value of the random backoff counter Ninit = 1 the channel sensing interval is not set according to the intention of the Ninit value so as to sense the channel during the slot duration period, and the channel for one additional slot duration interval is sensed according to step 3) It is set to sense the channel during efer duration (Td) and two slot duration (Tsi), and the channel sensing interval is set the same as when the Ninit value is set to 2. This means that channel sensing Section is set.

In the present invention, when the N value is 0, if the slot durations of the defer duration (Td) are idle, it is possible to instantaneously transmit the transmission including the PDSCH in the channel where the LAA Scell (s) transmission is performed, The channel access procedure is performed by differentiating the number of slot durations (Tsi) sensed in the case of setting Y (Y + 1) and Y (Ninit). (Y + 1) is selected as the Ninit value when the channel on the LAA Scell (s) to be transmitted is idle, channel sensing (Y + 1) is performed for defer duration (Td) + And transmits the transmission (s) including the PDSCH. When Y is extracted as the Ninit value, channel sensing is performed during defer duration (Td) + Y slot duration (Tsi) To transmit the transmitted transmission (s). Where Y can be zero and can be a natural number greater than or equal to zero.

FIG. 20 shows an example of a case where a channel is busy in one slot as an embodiment of the present invention described above. In this case, channel priority class 3 is used as a defer duration, 20- (a) extracted as Ninit = 2, (B), where Ninit = 1 is extracted.

The following is the operation of the base station and the terminal regarding the UL LBT operation.

The following describes a method for performing UL LBT for UL transmission in an LAA cell.

As one embodiment of a method of performing LBT for UL transmission in an LAA cell, there may be a case where UL transmission is successively performed next to DL transmission as shown in FIG. In FIG. 21, the last subframe of the LAA burst may be a full subframe (eg 1 ms, 14 OFDM symbols) or an ending partial subframe (eg, the number of occupied OFDM symbols is {3, 6, 9, 10, 11 12} Partial OFA symbols constituting the initial subframe (eg, 1 ms, 14 OFDM symbols) or OFA symbols smaller than 14 (eg 7 OFDM symbols) in the initial partial subframe, subframe.

Table below. B-1 is an occupied OFDM signal from a subframe configuration for a LAA field transmitted via common control signaling (i. E., PDCCH with DCI scrambled by CC-RNTI) as described in section 13 in 3GPP TS 36.213 v13.0.0. Represents configuration information about the number of symbols.

The common control signaling described in the present invention may mean a PDCCH having a DCI scrambled by a CC-RNTI as an example.

<Table-B-1. Subframe  configuration for LAA  in current and next subframe>

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, when the base station transmits UL grant in subframe n and UL transmission is performed in subframe n + 4, as shown in FIG. 21, The detetion of the common control signaling from the end of the on-going DL transmission burst transmitting the PDSCH to the SF # (n + 2) or the last SF # (n + 3) preceding the subframe (UE1) can recognize that the SF # (n + 3) is the last SF of the on-going DL transmission burst, it is determined that the transmission of UL is continuously established next to the DL transmitted subframe, Since the LBT is performed once in the DL for the transmission of the UL grant, the UL transmission intended for the UL grant may be transmitted without the UL LBT, or the channel may be transmitted through only the single sensing interval If it is idle, UL transmission may be performed, or UL transmission may be performed after UL LBT with back-off. The common control signaling described above transmits the configuration information of the current subframe and the configuration information of the next subframe as information transmitted by the base station. The terminal detects the configuration information of the next subframe and the configuration of the current subframe Information and last subframe configuration and whether the configuration of the last subframe of the DL transmission burst is a full subframe or 14 OFDM symbols or the number of occupied OFDM symbols as an ending partial subframe is {3, 6, 9 , 10, 11 12}.

However, if DL transmission in SF # (n + 3) is not full subframe as a behavior of the terminal and DL grant in SF # (n + 3) is not equal to DL subframe, the UL subframe boundary UE are (previously received scheduling) to: 1) perform the LBT once in the DL transmission when the UL grant hayeoteumeuro additionally for the UL transmission intended by the UL grant the UE to transmit or without UL LBT 2) back- reporting, or 3) single CCA interval to perform the UL LBT in the off idle until Ann Wu remaining UL subframe boundary transmits a reservation signal (s), or 4) UL subframe boundary just before performing UL transmission When reporting a single interval CCA idle and otherwise during the single interval period busy, the UL transmission associated with the UL grant can be set not to be transmitted . In this case, the UE can guarantee transmission in the UL subframe boundary from the viewpoint of UL transmission.

As another embodiment of the method of performing LBT for UL transmission in the LAA cell, when UL grant is received in SF # n as a behavior of the UE and DL transmission in SF # (n + 3) is Full subframe UL transmission at the UL subframe boundary can not be guaranteed. The UL DL transmission of the UE scheduled to be performed next to the last DL subframe is intended to be performed only when the DL subframe is configured as a full subframe since at least the switching time of the DL- The following two methods should be considered. First, the UL subframe in viewpoint of UL transmission should be always aligned in the boundary receiving the UL grant from the SF # n SF # (n + 3) 1 as a way to ensure that DL transmission is not scheduled to Full subframe at) the base station SF the UL grant transmitted from the UL subframe #n is intended to transmit the UL transmission in the SF # n + 4, and therefore the UL subframe for the DL transmission in the SF # In case of DL-UL switching time and UL LBT before boundary , transmission to the ending partial subframe can be scheduled so as to guarantee the interval for performing UL LBT . Or 2) DL transmission in SF # (n + 3) is transmitted through common control signaling in a full subframe. If transmission of UL grant is performed in SF # n, the BS determines that the last OFDM symbol is empty As shown in FIG. All of these methods may degrade base station scheduling flexibility.

As another embodiment of a method of performing LBT for UL transmission in the LAA cell, when UL grant is received in SF # n as a behavior of the UE and DL transmission in SF # (n + 3) is Full subframe, UL subframe Since the transmission of UL transmission at the boundary can not be guaranteed, the UL transmission is set to start from symbol # 1 or symbol # 2 when the SC-FDMA symbol index starts from behind one SC-FDMA symbol instead of UL subframe boundary. . The UE needs to guarantee at least the switching time of the DL-UL even if it is directly transmitted without performing the UL LBT for the UL transmission as the No UL LBT option. Therefore, when assuming UL transmission in the SC-FDMA symbol unit, FDMA symbol may be required, or a UL-LBT with a DL-UL switching time and a single sensing interval in at least one symbol, or a contention window size capable of performing back-off in one SC- That is, UL LBT when the number of slots of the CCA is 3 or 4, and the UE can perform UL transmission from the second SC-FDMA symbol. Alternatively, a method of performing UL LBT with back-off using two SC-FDMA symbols may be considered. In this case, the UL transmission may be transmitted from the third SC-FDMA symbol. In case of performing UL LBT through one or two SC-FDMA symbols, UL transmission in the UE performs rate matching considering the case where the first SC-FDMA symbol is missing, or UL transmission performs the first two The rate matching can be performed considering the case where the SC-FDMA symbol is missing.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, the UE transmits a UL grant in the UL LBT and the SF #n, and performs SF # n + 4 in the UL # And the common control signaling in SF # n + 3 to determine whether the last SF of the corresponding on-going DL burst is a full subframe or an ending partial subframe, the UL LBT It is possible to set whether the viewpoint is to be performed before the UL subframe boundary or within the UL subframe and rate-matching for transmission of the PUSCH to be transmitted on the UL subframe may be performed using implicit signaling by common control signaling have.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, there may be ambiguity of the UE at the time of the LBT for UL transmission in the position of the UE scheduled in SF # n + 5 in FIG. The UE scheduled to SF # n + 5 must perform transmission in the subframe boundary of SF # n + 5 in view of UL transmission at the UL subframe boundary. Therefore, the UE scheduled to transmit UL at SF # n + The last one or two SC-FDMA symbols of the PUSCH transmission in SF # n + 4 should be left empty as shown in Figure 21- (a) so that other UEs can perform LBT. However, when the DL transmission in SF # n + 3 is configured as a full subframe, since there is no time interval for performing UL LBT between UL subframe boundaries after DL subframe in SF # n + 3, Or the UL LBT should be performed using two SC-FDMA symbols. In the case of the UL transmission to be transmitted to the SF # n + 4 under the scenario of FIG. 22, since the subframe configuration in SF # n + 3 must be made only by the configuration of the full subframe, the first one or two SC- The UL LBT must be performed using the FDMA symbol. Therefore, since the scheduling can be performed independently from the UE in the UE's viewpoint, there may be ambiliency as described above regarding the point at which UL LBT is to be performed. Therefore, when UL LBT synchronization is required to maintain multiuser multiplexing between UEs, some UEs perform UL transmission at the UL subframe boundary by performing LBT ahead of UL subframe boundary, and the first one or two SC-FDMA the UEs attempting to perform the UL LBT in the UL subframe and performing the UL transmission may receive the first UL subframe of the UL subframe due to the UL transmission at the UL subframe boundary transmitted by the UEs that have performed UL LBT before the preceding UL subframe boundary, there is a high possibility that the channel is busy in the symbols, so that the UL transmission can not be performed in the SF # n + 4 even though the UL grant is received in the SF # n. Therefore, when transmitting an UL grant, signaling for the UL LBT at the terminal (ie, before the UL subframe boundary or in the first one or two SC-FDMA symbols in the UL subframe) is included in the UL grant. , Or signaling to the point at which UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to difference in UL LBT execution time between terminals and allowing multi-user multiplexing .

As another embodiment of the method for performing the LBT for the UL transmission in the LAA cell, when the UL LBT point set to one is used, because the specific terminal fails to detect the end of the common control signaling in the last SF # n + Even when the configuration information of the DL subframe is not known, the UL LBT time points between different UEs are different, and interference between the UEs is generated, thereby increasing the probability of LBT failure. Therefore, when transmitting an UL grant, signaling for the UL LBT at the terminal (ie, before the UL subframe boundary or in the first one or two SC-FDMA symbols in the UL subframe) is included in the UL grant. , Or signaling to the point at which UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to difference in UL LBT execution time between terminals and allowing multi-user multiplexing .

The following is a description of a method for performing uplink transmission without UL LBT, which is similar to a Wi-Fi ACK transmission immediately after DL 16s, and a UL LBT operation method for continuous UL transmission after DL transmission to an LAA cell .

In another embodiment of the method for performing LBT for UL transmission in the LAA cell, when the base station transmits UL grant in subframe n and UL transmission in subframe n + 4, as shown in FIG. 21, In the SF # (n + 3), a UE is scheduled to receive PDSCH as a DL transmission for an UE (eg, UE1) in the DL transmission from the eNB through decoding of the PDCCH / EPDCCH Or when an arbitrary UE recognizes that it is scheduled through PDCCH / EPDCCH decoding and PDSCH decoding succeeds, timing for performing UL transmission by self-carrier scheduling or cross-carrier scheduling in advance If the UL transmission is in the SF # (n + 4), the transmission of the UL grant is SF # n, and in the case of the TDD, the UL transmission according to the transmission of the UL grant is performed separately in Table C- If the relationship is (For example, 16us, 20us, or 25us, or a different value (for example, 16us, 20us, or 25us) after UL transmission of a UE ) So that it can be performed immediately. Or to perform only LBT during a single interval interval. Since the LBT is performed once in the DL when transmitting the UL grant, the terminal does not perform the UL LBT for UL transmission intended by the UL grant or performs a simple LBT operation without back-off to transmit the UL . Here, the UL transmission may be performed after a certain period regardless of the subframe boundary, or may be transmitted according to the OFDM symbol (or SC-FDMA symbol) boundary, or may be transmitted in accordance with the UL subframe boundary. There may be a way to transmit. However, it is desirable to set the DL-UL switching time considering the DL-UL switching time when setting an arbitrary interval.

Table C-1 k for TDD configurations 0-6

As another example of the method of performing LBT for UL transmission in the LAA cell, the success or failure of decoding of the DL PDSCH for an arbitrary UE in the last SF of the on-going DL transmission burst (e.g., UE1) (E.g., 16us, 20us, or 25us, or some other value) after UL transmission at which a UL transmission may occur at a subframe boundary or not. That is, since the processing time for decoding the PDSCH can not be guaranteed before the UL transmission after an arbitrary interval (for example, 16us, 20us, or 25us, or another value) after transmission of the on-going DL transmission burst, the decoding time of the PDSCH due to the decoding time of the PDSCH in a subframe boundary where decoding can not be determined or an arbitrary interval (for example, 16us, 20us, or 25us, or another value) If PDSCH decoding is performed despite the high level of interference due to high power level of the desired signal, the configuration of the ending subframe is indicated by subframe configuration through common control signaling for every SF. (n + 2) of the on-going DL transmission burst (eg UE1) because the UE # indicates the number of OFDM symbols occupied by the ending subframe (n + 3) is not an nding subframe and SF # (n + 3) is an ending subframe of an on-going DL transmission burst, (PDSCH) is transmitted and the PDSCH is decoded and succeeded, an arbitrary UE in the SF # (n + 3) is allocated to the UE (eg UE1) regardless of whether the PDSCH for the UE1 is scheduled For UL transmission, a UL grant transmitted by self-carrier scheduling or cross-carrier scheduling in advance (eg, (E.g., 16us, 20us, or 25us, or some other value) after the DL transmission of the on-going DL transmission bus without the UL LBT. Or to perform only LBT during a single interval interval. Since the LBT is performed once in the DL when transmitting the UL grant, the terminal does not perform the UL LBT for UL transmission intended by the UL grant or performs a simple LBT operation without back-off to transmit the UL . (For example, 16us, 20us, or 25us, or another value) after an arbitrary interval (for example, 16us, 20us, or 25us) Transmission may be considered, or it may be transmitted according to the OFDM symbol boundary, or there may be a method of transmitting according to the subframe boundary.

The following describes a method for performing UL LBT for UL transmission in an LAA cell as yet another embodiment.

22, there may be a case in which consecutive DLs of a DL that has received an UL grant and a UL transmission corresponding to the corresponding UL grant are discontinuously transmitted in order to continuously perform UL transmission after DL transmission . In FIG. 22, the UL transmission of the UL grant and the SF # n + 4 corresponding to the UL grant and the subsequent SF # n + 3 are discontinuous. In FIG. 22, the last subframe of the LAA burst may be a full subframe (eg, 1 ms, 14 OFDM symbols) or an ending partial subframe (eg, the number of occupied OFDM symbols is {3, 6, 9, 10, Partial OFA symbols constituting the initial subframe (eg, 1 ms, 14 OFDM symbols) or OFA symbols smaller than 14 (eg 7 OFDM symbols) in the initial partial subframe, subframe. In constructing an initial or ending partial subframe, it is not possible to construct a DL burst by a partial subframe alone.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, when the base station transmits UL grant in subframe n and UL transmission in subframe n + 4, as shown in FIG. 22, It is impossible to know whether or not the channel can be accessed by succeeding the LBT for DL transmission in SF # n + 3. Therefore, if the UE knows that the SF # n transmitting the UL grant is the last SF or if it can be known through the common control signaling, the UE uses the OFDM symbol before the UL subframe boundary for the UL transmission in the SF # n + And sets the UL LBT to the UL LBT during the forward OFDM symbol (eg 1 or 2 OFDM symbol) of SF # n + 4.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, when UL transmission is set to always perform transmission in the UL subframe boundary, the UL LBT before the UL subframe boundary The partial subframe in SF # n + 3 must be set as a partial subframe even though SF # n + 3 can be DL. The partial subframe in SF # n + 3 can not be constituted by the partial subframe alone. The subframe configuration in SF # n + 2 must be set to be a full subframe. To do so, the DL subframe in SF # n + 1 must first be configured as an initial partial subframe by performing CCA, or SF # n + Only LBT should be performed. In this case, the flexibility of scheduling can be reduced due to the DL scheduling restriction. Therefore, even if in a set, such as 22 SF # n + 3 is Full subframe configuration, DL-UL switching gap also can not be guaranteed 1) SF # n + 4, or to drop the UL transmission in, 2) No UL LBT or single sensing with the interval to perform the LBT has a back-off which to have a contention window size having or small value so that you can perform the LBT in SF # n + 4 one of the UL subframe or two A time interval for performing LBT with a DL-UL switching gap and a single sensing interval using a SC-FDMA symbol or a back-off having a contention window size with a small value Can be set. If the UE can recognize that the configuration in the last SF # n + 3 is a DL full subframe, the eNB determines whether the UE should perform the LBT at a certain time when transmitting the UL grant in SF # n. However, if the UE does not know the configuration information of the last DL subframe in the SF # n + 3 as a case, there is no way to know at what point the UE should perform the LBT. When UL LBT synchronization is required to maintain multiuser multiplexing between UEs, some UEs perform UL transmission at UL subframe boundary by performing LBT ahead of UL subframe boundary, and the first one or two SC-FDMA symbols The UEs attempting to perform the UL LBT and performing the UL transmission are required to transmit UL Since the UL transmission at the L subframe boundary is likely to cause the channel to be busy in the first one or two SC-FDMA symbols of the UL subframe, the UL transmission can not be performed even though the UL grant is received in the SF # n Lt; / RTI &gt; Therefore, when transmitting an UL grant, signaling for the UL LBT at the terminal (ie, before the UL subframe boundary or in the first one or two SC-FDMA symbols in the UL subframe) is included in the UL grant. , Or signaling to the point at which UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to difference in UL LBT execution time between terminals and allowing multi-user multiplexing .

The LBT method for performing transmission of a DL control channel (e.g., PDCCH, EPDCCH) considering transmission of UL grant only and transmission of UL data corresponding to the corresponding UL grant will be described.

As shown in FIG. 23, when the UL data traffic transmitted on the LAA SCell is self-carrier-scheduled through the control channel transmitted on the corresponding LAA SCell, the control channel transmitting only the UL grant is transmitted through the PDCCH of the DL sub- In the case of transmission, that is, when the UL grant only transmission is transmitted through the PDCCH without PDSCH transmission in one subframe, the OFDM symbols in the subframe that the PDSCH region can have may be blanked And the corresponding blanked OFDM symbol (s) of the unlicensed carrier may be allowed to access the medium from the blanked OFDM symbol (s) by channel access from other nodes or Wi-Fi nodes. Therefore, even though the BS attempts to secure the eNB transmission through the setting of the maximum channel occupancy time (MCOT) that can be set differently according to the channel access priority class, the LBT performed for the UL grant only transmission without the PDSCH is successful The PDSCH (s) and the scheduled PUSCH (s) are transmitted for transmission of the PDSCH and the scheduled PUSCH in the next subframes by transmission and interference by other nodes due to absence of PDSCH transmission in the corresponding subframe, Lt; / RTI &gt; 23 illustrates a case where a corresponding UL grant only transmission occurs in a start subframe of an LAA burst on an unlicensed carrier. However, the present invention is not limited to this case, but a subframe The same problem may occur when blanked OFDM symbols are generated in a subframe where UL grant only transmission is performed.

Method A) As shown in FIG. 24, in the case of UL grant-only transmission, the UL grant is transmitted through the EPDCCH, so that the EPDCCH is allocated in the PDSCH region with the PDSCH in the FDM scheme. PDSCH region, thereby preventing the medium from being accessed by the LBT in the blanked OFDM symbol (s) by the other nodes, and also preventing UL traffic corresponding to the corresponding UL grant In the LBT performance method used in the UE (s) at the time of transmission of the UL grant, depending on the LBT scheme performed at the time of transmission of the UL grant or the length of the MCOT secured at the time of transmission of the UL grant, it is possible to perform fast channel access for UL data transmission by performing LBT in a single interval LBT interval (for example, 16 us, 25 us, 34 us or 43 us). Or in the LBT performing method used in the UE (s) at the time of transmitting the UL traffic corresponding to the UL grant, depending on the LBT scheme performed at the time of transmitting the UL grant or the length of the MCOT secured at the time of transmitting the UL grant, When transmitting UL traffic from outside, it can be configured to perform cat-4 LBT. Alternatively, a method for signaling whether the terminal should perform a cat-4 LBT method to perform a single interval LBT to enable fast channel access as an LBT for UL traffic or to perform a backoff in the case Can be considered.

Method B) When UL grant only transmission without PDSCH transmission in one subframe is transmitted through PDCCH or EPDCCH, as shown in FIG. 25, when the LBT in the subframe in which the UL grant only is transmitted and the PDSCH in the next subframe are transmitted In the subframe, a method may be considered in which the LBT is set to be independent of the LBT in the subframe for UL grant only transmission so as to match the channel access priority class for the PDSCH. In this case, when the LBT is successful according to the success of the LBT in the subframe where the PDSCH is transmitted, the MCOT is set from the corresponding subframe. However, the UL subframe in which the UL traffic corresponding to the pre- The UE can perform LBT in a single interval LBT interval (for example, 16us, 25us, 34us, or 43us) to enable fast channel access for UL data transmission if the UE exists in the MCOT. Or the LBT scheme performed in the UL grant transmission in the LBT performance method used in the UE (s) at the time of transmitting the UL traffic corresponding to the UL grant or the length of the MCOT secured by the LBT in the subframe transmitting the PDSCH 4 LBT when UL traffic is transmitted outside the MCOT. Alternatively, a method for signaling whether the terminal should perform a cat-4 LBT method to perform a single interval LBT to enable fast channel access as an LBT for UL traffic or to perform a backoff in the case Can be considered.

Method C As shown in FIG. 26, in order to prevent a case where a blank OFDM symbol (s) occurs in a PDSCH region, which may occur when UL grant only transmission is transmitted through a PDCCH, In order to prevent access to medium by LBT in blanked OFDM symbol (s) by nodes, the PDSCH to be transmitted in the next subframe can be transmitted without additional LBT in MCOT. As an example of the reservation signal, there may be one EPDCCH transmission common to all UEs. In another embodiment, the transmission at the 0, 4, 5, and 7 OFDM symbol indexes of the CRS ports 0 to 1, symbol, and CRS ports 0 to 4 may be extended and transmitted, and a method of transmitting dummy data to a RB in a specific frequency region as a reservation signal may be considered. Also, in the LBT performance method used in the UE (s) at the time of transmitting the UL traffic corresponding to the corresponding UL grant, depending on the length of the MCOT secured at the transmission of the UL grant or the LBT scheme performed at the time of transmission of the UL grant, UL traffic may be performed in a single interval LBT interval (for example, 16us, 25us, 34us, or 43us) to enable fast channel access for UL data transmission. Or in the LBT performing method used in the UE (s) at the time of transmitting the UL traffic corresponding to the UL grant, depending on the LBT scheme performed at the time of transmitting the UL grant or the length of the MCOT secured at the time of transmitting the UL grant, When transmitting UL traffic from outside, it can be configured to perform cat-4 LBT. Alternatively, a method for signaling whether the terminal should perform a cat-4 LBT method to perform a single interval LBT to enable fast channel access as an LBT for UL traffic or to perform a backoff in the case Can be considered.

24 to 26 illustrate a case where a corresponding UL grant only transmission occurs in a start subframe of an LAA burst on an unlicensed carrier as an example, and a solution thereof is shown in Figs. 24 to 26 and methods A to C The present invention is not limited to this, but a problem that occurs when a blanked OFDM symbol is generated in a subframe in which UL grant only transmission is performed in a subframe other than the beginning of an LAA burst in an unlicensed carrier is also described with reference to FIGS. 26 and Methods A-C. 23 to 26 in the present invention are described with reference to a full subframe (e.g., a subframe composed of OFDM symbols). However, when the starting subframe is a partial subframe (e.g., a subframe composed of OFDM symbols smaller than 14) the present invention can be applied to a case in which the partial subframe is composed of partial subframes.

In the case of transmitting only an UL grant, an LBT method of a DL control channel (e.g., PDCCH, EPDCCH) including an UL grant considering a channel access priority class of UL traffic corresponding to an UL grant, The LBT method for transmission will be described.

The LBT method for UL traffic transmission corresponding to the UL grant when the UL grant is transmitted together with the PDSCH transmission will be described.

First, when the UL grant is transmitted together with the PDSCH transmission, the PDCCH as the control channel and the LBT of the EPDCCH to which the UL grant is transmitted are transmitted through the channel using the LBT parameters according to the channel access priority class of the PDSCH access.

Assuming that the minimum time latency between the UL grant and the UL transmission is 4 ms, since the MCOT is 2 ms or 3 ms when the CAPC of the PDSCH is 1 or 2, the UL grant corresponding to the UL grant is transmitted as the UL grant (Hereinafter referred to as &quot; MCOT &quot;) of the DL transmission burst. Therefore, the LBT of the UL Transmission corresponding to the UL grant can be set to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE receiving the UL grant and transmitting the UL. If the UE has multiple CAPCs to transmit, the UE can be configured to perform Cat-4 LBT based on the CAPC having the lowest priority among the CAPCs.

As another embodiment, when the CAPC of the PDSCH transmitted with the UL grant is 3 or 4, since the MCOT is 8 ms or 10 ms, the UL transmission corresponding to the UL grant can be transmitted in the MCOT or can be transmitted outside the MCOT . If DL transmission and transmission of UL LBT and UL transmission can occur in MCOT, single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, UL transmission, UL LBT and UL transmission can not occur in the MCOT. For UL transmission that can occur within the MCOT limit, single interval UL transmission scheduled to be carried out by the UL grant so that UL transmission is performed through LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, N can be a natural number of 1 or more) For transmission, the terminal may be configured to perform LBT according to the CAPC of UL traffic to be transmitted. If the UE has multiple CAPCs to transmit, the UE can be configured to perform Cat-4 LBT based on the CAPC having the lowest priority among the CAPCs.

In another embodiment, when the CAPC of the PDSCH transmitted with the UL grant is set to 3 and the UL grant is also performed according to the CAPC 3, the CAPC of the UL traffic to be actually transmitted by the UE corresponding to the UL grant is 3 or less UL transmission is performed through a single interval LBT (eg, 16us, 25us, 34us, 43us or 16 + 9 * N, where N may be a natural number of 1 or more) regardless of the CAPC of the UL traffic , And if the CAPC of the UL traffic is 4, it can perform the UL transmission by performing the cat-4 LBT with the LBT parameter according to CAPC 4 of the UL traffic regardless of whether the UL transmission is within the MCOT or outside the MCOT have. As another embodiment, when the CACP of the PDSCH transmitted with the UL grant is set to 4 and the UL grant is also performed according to the CAPC 4, the terminal corresponding to the UL grant transmits a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1).

As another embodiment, when the LBT is performed through the CAPC value X of the PDSCH transmitted with the UL grant, a single interval LBT (eg, 16us, 25us, 34us, 43us or 16 + 9 * N, N may be a natural number greater than or equal to 1), and if not, UL transmission scheduled according to the UL grant is performed according to the CAPC of UL traffic to be transmitted by the UE LBT &lt; / RTI &gt; If the UE has multiple CAPCs to transmit, the UE can be configured to perform Cat-4 LBT based on the CAPC having the lowest priority among the CAPCs.

As another embodiment of the present invention, a base station may perform LBT-related signaling, i.e., a CAPC (eg, channel access priority class {1, 2, 3, or 4}) or a CW Or CWp) to the terminal. At this time, the UE compares the CAPC and the CW of the UL traffic to be transmitted by the UE based on the CAPC as the DL LBT or the CW performed by the base station for UL grant transmission in the transmission of the UL transmisson corresponding to the corresponding UL grant, If the CAPC or CW as the LBT is equal to or greater than the CAPC or CW of the UL traffic, the UL transmission (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) And if it is not, it may be configured to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant. This method can be applied regardless of whether the UL grant (s) and the UL grant corresponding to the UL grant (s) are within the MCOT and whether the UL grant is transmitted concurrently with the PDSCH or only the UL grant It is applicable.

The present invention provides a UL traffic transmission corresponding to an UL grant when an UL grant is transmitted together with a PDSCH transmission in consideration of a contention window (CW) and a channel access priority class (CAPC) used in an LBT in a terminal and a base station And an LBT method of a channel through which an UL grant is transmitted will be described. The present invention also describes an LBT method of a DL control channel (e.g., PDCCH, EPDCCH) including UL traffic and UL grant corresponding to UL grant when only UL grant is transmitted.

First, an LBT method for UL grant transmission and an LBT setting method for UL traffic corresponding to an UL grant in a case where an UL grant is transmitted together with transmission of a PDSCH will be described.

1-1) When the base station manages the CW specific to the UE for each UE or each UE (s) allows the base station to know the CW of the UE,

It may be difficult for the BS to know the CAPC of the UL traffic to be transmitted by each UE before transmission of the UL grant. Therefore, the BS determines the CW according to the CAPC for the PDSCH (s) to be transmitted and performs the DL LBT for the control channel and the PDSCH transmission, and the DL grant included in the control channel is also performed in the same DL LBT. At this time, in a method for performing UL LBT for transmission of UL traffic (s) corresponding to an UL grant (s), a CW (eg CW_eNB) of DL LBT parameters used by a base station for transmission of UL grant, The UL LBT for transmission of the scheduled UL traffic (s) corresponding to the UL grant (s) is compared with the single interval LBT (s) by comparing them based on the CW (eg CW_UE For example, if UL transmission is set to perform UL transmission through a UL grant (e.g., 16us, 25us, 34us, 43us, or 16 + 9 * N, N may be a natural number greater than or equal to 1) May be configured to perform LBT according to the CAPC of UL traffic to be transmitted. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. In addition, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like.

More specifically, the CW (eg, CW_eNB) as a DL channel access parameter used by the base station for transmission of the UL grant (s) is used as the traffic (s) of the UE (s) scheduled by the UL grant (s) ) Or a maximum value of the CWs (eg CW_UE (s)) for the UL grant (eg, Equation 4-1 or Equation 4-2), the base station transmits a CW having a sufficient length (Eg 16us, 25us, 34us, 43us or 16 + 9 * N) to perform fast channel access as UL LBT for UL transmission for UL traffic corresponding to UL grant (s) N may be a natural number greater than or equal to 1). As an example, the corresponding case can be expressed by the following Equation 4-1 or Equation 4-2. Equation 4-1 is a condition that is equal to or greater than the maximum value of the CWs (eg CW_UE_i, p_j) of all CAPCs for the traffic (s) of the UE (s) scheduled by the UL grant (s) Equation 4-2 represents the maximum value of the CWs (eg CW_UE_i, p_j) of the same CAPC for the traffic (s) of the UE (s) scheduled by the UL grant (s) It is a representation of the condition of greater or equal.

Equation (4-1)

Here, p_j denotes an index of the channel access priority class, and i denotes an index of the UE (s) scheduled by the UL grant (s).

Equation (4-2)

Here, p_j denotes an index of the channel access priority class, and i denotes an index of the UE (s) scheduled by the UL grant (s).

CW for the UL traffic (s) of the UE (s) scheduled by the UL grant (s) managed by the base station, CW as the channel access parameter used for the transmission of the UL grant (s) The UE can be configured to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. In addition, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like.

As another embodiment, as a method for enabling fast channel access to the UL traffic (s) of the UE (s), a UE to be scheduled for CW (or CAPC) in the eNB for performing LBT on the control channel and PDSCH transmission (or CAPCs) with respect to the UL traffic (s) of the base station (s) to perform the DL LBT for the control channel including the UL grant and the PDSCH transmission. This is set so that the CW value of the LBT used for transmission of the UL grant (s) is not less than the CW (or CAPC) maximum of the UL traffic (s), so that for UL transmission for UL traffic corresponding to the UL grant it is possible to perform UL transmission through fast channel access, ie, single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1). In addition, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like.

1-2) If the base station manages only the CW for the base station transmission without the CW information of the terminal and each UE (s) manages the CW,

In one embodiment, the BS informs the UE of UL grant or common control signaling of the CW or CAPC of the LBT performed by the BS to transmit the UL grant (s), thereby enabling the UE to detect UL grant or common control signaling UL LBT for transmission of scheduled UL traffic (s) corresponding to UL grant (s) through comparison of CW with UL traffic or CAPC comparison for UL transmission corresponding to UL grant according to information is called single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N is a natural number greater than or equal to 1) The UE can perform the LBT according to the CAPC of the UL traffic to be transmitted. When the CW comparison is performed and the UL LBT scheme is set, if the CW at the time of transmission of the UL grant is equal to or greater than the CW of the UL traffic managed by the scheduled UE corresponding to the UL grant, the single interval LBT is performed And if not, perform the cat-4 UL LBT based on the CW of the UL traffic managed by the UE. In the case of setting the UL LBT scheme by performing the CAPC comparison, the single-interval LBT is performed when the CAPC at the transmission of the UL grant is equal to or greater than the CAPC of the scheduled UL traffic corresponding to the UL grant, 4 UL LBT based on the CAPC of the UL traffic managed by the UE.

In another embodiment, when an LBT performed by a base station for UL grant (s) transmission is performed according to a CAPC of a PDSCH (s), if there is an UL transmission by an UL grant (s) in the MCOT, UL transmission is performed through a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) The UL can perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant.

The following describes an LBT method for UL grant transmission and an LBT setting method of UL traffic corresponding to the UL grant when only UL grant is transmitted without PDSCH transmission.

2-1) When the base station manages the UE-specific CW for each UE or each UE (s) makes the base station know the CW of the terminal,

In the case where only UL grant is transmitted without PDSCH transmission, it is not known what values to use as DL channel access parameters for UL grant. Therefore, the base station arbitrarily selects the DL channel access parameter, but the DL selected for the transmission of the UL grant (s) (eg CW_EnB) for the traffic (s) of the UE (s) scheduled by the UL grant (s) managed by the base station is greater than the maximum value of the CWs (eg CW_UE (s) In the same case (eg, Equation 4-1 or Equation 4-2), since the base station has performed the DL LBT with a CW of sufficient length from the transmission of the UL grant, the UL grant (s) corresponding to the UL grant UL transmission can be configured to perform UL transmission through a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) to perform fast channel access as a UL LBT. have. As an example, the corresponding case can be expressed by the following Equation 4-1 or Equation 4-2. Equation 4-1 is a condition that is equal to or greater than the maximum value of the CWs (eg CW_UE_i, p_j) of all CAPCs for the traffic (s) of the UE (s) scheduled by the UL grant (s) Equation 4-2 represents the maximum value of the CWs (eg CW_UE_i, p_j) of the same CAPC for the traffic (s) of the UE (s) scheduled by the UL grant (s) It is a representation of the condition of greater or equal. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. Further, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like

CW for the UL traffic (s) of the UE (s) scheduled by the UL grant (s) managed by the base station, CW as the channel access parameter used for the transmission of the UL grant (s) The UE can be configured to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. In addition, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like.

As another embodiment of the present invention, as a method for enabling fast channel access to UL traffic (s) of UE (s), scheduling of CW (or CAPC) in the eNB for performing DL LBT of a control channel including only UL grants (Or CAPCs) with respect to the UL traffic (s) of the UE (s) to be performed, and perform the DL LBT for the control channel including the UL grant. This is set so that the CW (or CAPC) value of the LBT used for transmission of the UL grant (s) is not less than the CW (or CAPC) maximum of the UL traffic (s) For UL transmission, UL transmission can be performed through fast channel access, ie single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1). In addition, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like.

2-2) If the base station manages only the CW for the base station transmission without the CW information of the terminal and each UE (s) manages the CW,

In one embodiment, the BS informs the UE of UL grant or common control signaling of the CW or CAPC of the LBT performed by the BS to transmit the UL grant (s), thereby enabling the UE to detect UL grant or common control signaling UL LBT for transmission of scheduled UL traffic (s) corresponding to UL grant (s) through comparison of CW with UL traffic or CAPC comparison for UL transmission corresponding to UL grant according to information is called single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N is a natural number greater than or equal to 1) The UE can perform the LBT according to the CAPC of the UL traffic to be transmitted. When the CW comparison is performed and the UL LBT scheme is set, if the CW at the time of transmission of the UL grant is equal to or greater than the CW of the UL traffic managed by the scheduled UE corresponding to the UL grant, the single interval LBT is performed And if not, perform the cat-4 UL LBT based on the CW of the UL traffic managed by the UE. In the case of setting the UL LBT scheme by performing the CAPC comparison, the single-interval LBT is performed when the CAPC at the transmission of the UL grant is equal to or greater than the CAPC of the scheduled UL traffic corresponding to the UL grant, 4 UL LBT based on the CAPC of the UL traffic managed by the UE.

In another embodiment, when the base station performs an LBT performed for UL grant (s) transmission according to a CAPC arbitrarily set by the base station, if the UL transmission by the UL grant (s) is present in the MCOT, the scheduled UL traffic s UL transmission through a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) When the UL transmission is scheduled, the UE can perform the LBT according to the CAPC of the UL traffic to be transmitted to the UL transmission scheduled by the UL grant.

The present invention relates to a CWS adaptation method for UL LBT in a terminal.

In the case where the base station manages the CW specific to the UE or each UE (s) knows the CW of the UE, the base station may update and adapt the CW of the UE (s) CW update and adaptation of each terminal can be performed based on the UL transmission. In the case of the terminal, the PUSCH transmission in the unlicensed carriers may be dropped in the power limited situation of the terminal according to the priority between the channels of the licensed carriers and the channels of the unlicensed carriers in the operation based on the carrier aggregation. However, the BS can not know the power limited situation of the UE and can not know whether the UE has transmitted the channels dropped due to the power limitation, but expects the UE to transmit the scheduled channel and expect the reception at the corresponding reception timing . However, in this case, when the UL transmission transmitted by the UE drops, the BS determines it as a NACK and uses the contention window (CW) according to the NACK as information for updating the CW. In this case, dropped UL transmission may not be useful information for determining whether the channel is busy or idle between the UE and the BS. Therefore, when the base station performs CW update and adaptation for each UE, the base station updates the base station based on reception from the base station of the PUSCH transmitted by the mobile station. If base station decoding based on the PUSCH transmission is determined to be ACK The CW of the corresponding UE is reset, and the UE determines that the channel for the medium between the UE and the BS is idle, and the CWp (p = {1,2,3, 4} may be reset to CWmin, and when it is determined that the base station decoding based on the PUSCH transmission is failed and NACK is determined, the CW of the corresponding UE is doubled. At this time, It is judged that the channel is busy, so that CWp (p = {1,2,3,4}), which may be differently set according to the channel access priority class, is doubled for all CWp . In addition, as a method of recognizing the PUSCH transmission from the UE, the base station may perform energy detection on the PUSCH transmission through detection of the UL DM-RS, or when the PUSCH is scheduled with the SRS, energy detection may be performed to determine whether the PUSCH is transmitted.

Each UE can use the new data indication (NDI) information included in the UL grant to update and adapt the CW. When the transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe indicates the new data indication, the NDI is toggled in the UL grant received in the n th subframe from the base station, the CW Reset, that is, CW_min value to set the current CWp. If the NDI does not indicate a new data indication in the UL grant received from the base station from the n th subframe and retransmission of the PUSCH in the (n-4) th UL subframe is instructed and the NDI is not toggled, At this point, the current CW is doubled and the LBT is performed using the CW doubled as the CW value for transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CWp is set to the CW_min value.

In the case where the base station manages only the CW for the base station transmission without information on the CW of the UE and each UE (s) manages the CW, the method of updating and adapting the CW of each UE (s) Each UE can update and adapt CW using new data indication (NDI) information included in the UL grant. When the transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe indicates the new data indication, the NDI is toggled in the UL grant received in the n th subframe from the base station, the CW Reset, that is, CW_min value to set the current CWp. If the NDI does not indicate a new data indication in the UL grant received from the base station from the n th subframe and retransmission of the PUSCH in the (n-4) th UL subframe is instructed and the NDI is not toggled, At this point, the current CW is doubled and the LBT is performed using the CW doubled as the CW value for transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CWp is set to the CW_min value.

(About UL LBT failed procedure)

The present invention relates to the behavior of the UE (s) in case the UE (s) fails the LBT and the base station transmits the UL grant (s) for the scheduled PUSCH to the UE (s) After a UE (s) performs a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) or cat-4 based LBT for transmission of PUSCH, LBT the behavior procedure of the terminal in case of failing is explained.

When a UE is scheduled to perform UL transmission continuously, that is, when a UL grant (s) included in a control channel of each DL subframe is transmitted to a UE from a continuous multiple DL subframe, or when multi there may be a case where continuous UL transmission is performed through one UL grant included in a control channel of one DL subframe by -subframe scheduling. In these cases, in a case where a continuous UL subframe is scheduled to the same UE as an embodiment of the present invention, the LBT (eg, 16us, 25us, 34us, 43us or 16 + 9 * N, N may be a natural number greater than or equal to 1), or cat-4 based LBT fails, UL scheduling in the corresponding UL subframe may result in scheduling in the corresponding UL subframe according to the result of LBT failure for the corresponding UL subframe The UL transmission in the next subframe can be configured to transmit the reservation signal so that the UL transmission in the next subframe can be determined through the LBT in the next subframe. A method may be considered in which the Reservation signal is transmitted until the LBT point of time of the next subframe that is scheduled to determine whether to perform UL transmission depending on the LBT in the next UL subframe. As an embodiment of the reservation signal transmission method, a method of transmitting a reservation signal only to a subset of resources that can be transmitted due to an LBT failure although being scheduled for UL transmission may be considered. Alternatively, A method may be considered in which a reservation resource is transmitted to a dedicated resource of a corresponding UL subframe by setting a predetermined dedicated resource as a known signal of the BS and the MS. This method may be applied as an operation in the MCOT set by the base station. However, considering the case of cross-DL burst scheduling, the method can be applied to the operation outside the MCOT set by the base station , A continuous UL subframe may be applied if it is within the same MCOT.

In the case of UEs not scheduled at the start time of the UL subframe, the UL transmission of other UEs that are scheduled first after the transmission of the DL is scheduled to be transmitted in the nth subframe, (N + 1) th, (n + 2) th or (n + 3) th UL subframe other than the n th subframe in which the UL subframe is scheduled to be transmitted, In the case of UE # 1, it is also possible to consider a method of making a reservation signal transmission so that UL transmission in the next UL subframe can be determined through LBT in the next subframe. A method may be considered in which the Reservation signal is transmitted until the LBT point of time of the next subframe that is scheduled to determine whether to perform UL transmission depending on the LBT in the next UL subframe. As an embodiment of the reservation signal transmission method, a method of transmitting a reservation signal only to a subset of resources that can be transmitted due to an LBT failure although being scheduled for UL transmission may be considered. Alternatively, A method may be considered in which a reservation resource is transmitted to a dedicated resource of a corresponding UL subframe by setting a predetermined dedicated resource as a known signal of the BS and the MS. This method may be applied as an operation in the MCOT set by the base station. However, considering the case of cross-DL burst scheduling, the method can be applied to the operation outside the MCOT set by the base station , A continuous UL subframe may be applied if it is within the same MCOT.

As another embodiment of the present invention, when the base station is scheduling UL to a plurality of UEs, information on whether a UL subframe to be scheduled at the time of transmitting an UL grant is a last UL subframe for UEs in a cell in which scheduling is performed . Accordingly, it is possible to indicate through the control signaling to the UE whether the UL is the last UL subframe among the UEs that have been schduled by the corresponding BS. An indication method through control signaling may be a method of informing through a DL common control signal in a DL transmitting an UL grant or a method of indicating through a common control signal for UL in one embodiment . Alternatively, there may be a way for the base station to provide an indication of the last UL subframe in the UL grant. In case of multiple subframe scheduling, the BS can indicate that the last subframe of a multiple subframe scheduled with UL grant is the last subframe. When the UE receives information according to the indication of the last UL subframe, if the UL subframe performing the LBT for the scheduled UL transmission is the last UL subframe, if the UE fails the UL LBT (single interval LBT or Cat-4 LBT) The UL PUSCH transmission indicated by the UL grant in the corresponding UL subframe is dropped. However, if the UL subframe scheduled by the UL grant does not receive the instruction of the last subframe or is not the last subframe, transmission of the UEs scheduled in the next subframe is transmitted to the success or failure of the LBT in the next subframe by transmitting a specific reservation signal. Ensure that you can decide whether to perform.

A method may be considered in which the Reservation signal is transmitted until the LBT point of time of the next subframe that is scheduled to determine whether to perform UL transmission depending on the LBT in the next UL subframe. As one embodiment of the reservation signal transmission method, a method of transmitting only a subset of resources scheduled for UL transmission may be considered, or in another embodiment, a known signal for a reservation signal and a terminal may be preset A dedicated resource may be set up to transmit a reservation signal to the dedicated resource. This method may be applied as an operation in the MCOT set by the base station. However, considering the case of cross-DL burst scheduling, the method can be applied to the operation outside the MCOT set by the base station , A continuous UL subframe may be applied if it is within the same MCOT.

As another exemplary embodiment of the present invention, the LBT for the UL transmission scheduled for the UL grant and the LBT (eg, 16us, 25us) set for the UE in the UL subframe, regardless of the single subframe scheduling or the multiple subframe scheduling, , 34us, 43us, or 16 + 9 * N, N may be a natural number greater than or equal to 1), or cat-4 based LBT failure.

(With respect to the LBT for the PUSCH including PUCCH and UCI information)

PUCCH is used as a non-scheduled channel, unlike PUSCH, which receives scheduling information from a base station. If simultaneous transmission of PUCCH + PUSCH is configured, simultaneous transmission of PUCCH and PUSCH is possible. Otherwise, UCI information such as CQI, RI, and PMI for the DL PDSCH transmission may be piggybacked to the scheduled PUSCH and if the scheduling of the PUSCH is not scheduled from the base station, HARQ-ACK values for HARQ -ACK values and a CQI can be transmitted. Therefore, UCIs on unlicensed carriers can be transmitted on the unlicensed carrier to the uplink PUCCH or PUSCH. In this case, the LBT method of the PUSCH including the PUCCH or UCI in the unlicensed carrier is set as follows, LBT can be performed.

First, in case of transmitting the ACK, NACK, NACK / DTX and DTX values as the HARQ-ACK for the PUCCH and transmitting the periodic CSI and the HARQ-ACK values in one PUCCH format, periodic CSI may be transmitted at the same time. The values as HARQ-ACK for the PDSCH may be the most priority information that should be fed back to the base station in terms of DL throughput and may precede the priority of the periodic CSI values for link adaptation. Therefore, in the case of non-scheduled PUCCH, (E.g., 16us, 25us, 34us, 43us or 16 + 9 * N, where N may be a natural number equal to or greater than 1) as a fast channel access when HARQ-ACK for the PDSCH is included in the PUCCH transmitted from the BS. , Or a method of performing channel access using the highest priority class in the channel access priority class (eg, channel access priority class # 1). In addition, when only CQI is transmitted to the PUCCH, it can be configured to perform cat-4 LBT. This is because the channel state information (CSI) in the unlicensed carrier may not be significant in the CSI under the condition that channel access is not guaranteed.

In addition, the LBT method of the PUSCH can be set according to whether the HARQ-ACK value is included in the UCI for the PUSCH including the UCI. When the HARQ-ACK for the PDSCH is included in the PUSCH including the UCI, the UE may use a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * ) Or a method of allowing channel access to be performed based on a class having the highest priority in the channel access priority class (for example, channel access priority class # 1) can be considered. In addition, when only CQI is transmitted to the PUSCH, it can be configured to perform cat-4 LBT. However, in the case of the PUSCH including the UCI, when an UL grant for performing scheduling of the PUSCH is transmitted in the DL transmission, the LBT is performed in advance and the LBT of the PUSCH according to the LBT method used for transmission of the UL grant, If the PUSCH LBT is to be transmitted using fast channel access, the transmission of the PUSCH including UCI should be performed by overriding the corresponding LBT method. If not, the fast channel UL LBT and HARQ-HARQ, which are set depending on the UL grant only for transmission of the PUSCH having the UCI including the HARQ-ACK, can be configured to perform transmission of the PUSCH with the UCI using the LBT method capable of access, A predetermined LBT for transmission of a PUSCH having a UCI including an ACK, a PUSCH having a UCI including a HARQ-ACK using a LBT method capable of fast channel access, Can be set to perform transmission.

(PDCCH order in Random Access procedure, PRACH and LBT for RAR)

In case of triggering non-contention-based PRACH transmission by PDCCH order, the PDCCH transmitted to UE in order to set up LBT for PDCCH to trigger UL synchronization is a single interval LBT (eg 16us (Eg, 25us, 34us, 43us, or 16 + 9 * N, N can be a natural number greater than or equal to 1) or by assigning the highest priority class in the channel access priority class as the channel access priority class # A method of allowing access to the channel for the channel can be considered. In case of carrying the PDCCH and the PDSCH for the same UE or another UE (s) in the DL subframe including the PDCCH for PRACH triggering, the LBT parameter according to the channel access priority class set for the corresponding PDCCH / PDSCH transmission eg, m_p, CW_min, CW_max, T_mcot, and allowed CW_p sizes.

Next, PRACH is a random access preamble channel. It is considered as the highest priority channel when the UE is a power limitation in CA (Carrier Aggregation). Therefore, the PRACH is different from other UL channels (eg PUCCH, PUSCH with UCI, PUSCH w / o UCI) and the signal (eg, a sounding reference signal), the transmission power of the PRACH is guaranteed to be the highest priority, or other UL channels or signals may be dropped to guarantee transmission of the PRACH. Therefore, if the PRACH transmission is configured, there may be a method of setting to be transmitted without LBT as fast channel access. If PRACH transmission fails due to LBT, the UE can not guarantee uplink transmissions because it can not synchronize on unlicensed carriers. This can increase unnecessary latency considerably. Therefore, LBT for PRACH It is possible to set the terminal to perform transmission to the base station without performing the transmission. Or by using a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) or the highest priority class in the channel access priority class class # 1) to perform channel access to the PRACH.

With respect to the random access response (RAR), after transmitting the random access preamble as described above, the terminal attempts to receive its random access response in the random access response reception window indicated by the system information or the handover command . A random access response (RAR) is transmitted in the form of a MAC PDU, and the MAC PDU is delivered to the PDSCH. The PDCCH is also transmitted together with the PDSCH to properly receive the information transmitted on the PDSCH. The PDCCH includes information of a UE to receive the PDSCH, frequency and time information of the PDSCH, and a transmission format of the PDSCH. Once the UE succeeds in receiving the PDCCH to itself, it appropriately receives the random access response transmitted on the PDSCH according to the information of the PDCCH. The random access response includes a random access preamble identifier, an UL grant, a temporary C-RNTI (Temporary C-RNTI), and a time alignment correction value (Time Alignment Command). The random access preamble identifier is necessary because random access response information for one or more UEs can be included in one random access response. Therefore, the uplink grant, the temporary C-RNTI, To indicate if it is valid. Unlike the contention-based random access procedure, the non-contention-based random access procedure determines that the random access procedure has been normally performed by receiving the random access response information, and terminates the random access procedure. Further, the non-contention-based random access procedure may be performed in the case of the handover process and in the case of being requested by the base station. For a non-contention-based random access procedure, it is important to receive a dedicated random access preamble from the base station that has no possibility of collision. As a method for receiving the random access preamble, there are a handover command and a PDCCH command. In addition, the BS may set a PRACH resource in which the UE transmits the random access preamble. The PRACH resource includes a subframe and a frequency resource used by the UE for random access preamble transmission. Table 10 below shows the PRACH mask indexes for the base station to set the PRACH resource to the UE. For example, in the FDD mode, the UE may transmit a random access preamble (Random Access Preamble) in only one subframe among 10 subframes, an even subframe, or an odd subframe, according to a PRACH mask index Lt; / RTI &gt;

Table 10

In such a random access procedure, the RAR in the contention-based or non-contention-based random access procedure is delivered to the UE through the PDSCH. Therefore, if there is a PDSCH to transmit to other UEs except for a case where RAR is independently transmitted, the LBT parameter is applied according to the channel access priority class set by the BS in order to transmit the corresponding PDSCH (s) The PDCCH / PDSCH for the RAR transmitted to the UE in order to prevent unnecessary latency due to the random access procedure in the case where the RAR is independently transmitted without PDSCH transmitted to other UEs, (eg, channel access priority class # 2) using the LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) 1) to perform channel access to the PDCCH / PDSCH for the RAR.

The present invention can be applied to a case where the UE can transmit UL, ACK, NACK, NACK / DTX, and DTX values on the unlicensed carrier as HARQ ACKs for the PDSCH (s) A method of performing CW update and adaptation for DL transmission in a base station will be described.

(In the case where the HARQ-ACK for the PDSCH (s) transmitted to the DL on the LAA Scell is transmitted only to the UL on the unlicensed carrier, LAA SCell)

When the HARQ-ACK for the PDSCH (s) transmitted to the DL on the unicensed carrier, LAA Scell, is transmitted to the unlicensed carrier only in the UL on the LAA SCELL, the HARQ-ACK (s ), The BS sets the contention window (CW) for the DL PDSCH (s) transmission in the LAA SCell to be reset, and if not, doubles the CW. That is, if the base station detects at least one ACK from the UE for the PDSCH (s) transmitted from the base station after successful decoding of the PUCCH or PUSCH including the HARQ-ACK transmitted from the UE on the LAA SCell, The base station determines that the channel for the medium between the base station and the terminal is idle, and the CWp (p = {1,2,3,4), which may be differently set according to the channel access priority class, } May be reset to CWmin and decoding of the PDSCH (s) in the UE according to the corresponding PDSCH transmission may fail, so that the UE transmits a feedback in the NACK so that the NACK or NACK / DTX or DTX is detected Or determines that the corresponding base station doubles the CW. The base station doubles the CW even in the case of NACK or NACK / DTX or DTX detection in the base station, which may occur due to transmission of PUCCH or PUSCH including HARQ-ACK transmitted from the UE in the unlicensed carrier. In this case, the base station determines that the channel for the medium between the BS and the MS is busy, and thus the CWp (p = {1,2,3,4}), which may be differently set according to the channel access priority class, Set CWp to doubling. Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

When the number of unlicensed carriers increases, it may not be possible to transmit the HARQ-ACK value only to the UL of a specific unlicensed carrier. In addition, HARQ-ACK transmission may be performed on the UL in a group unit capable of transmitting the HARQ- Can be achieved. If there is not much transmission of the DL PDSCH on the unlicensed carrier, it is possible to transmit the HARQ-ACK only in the UL of the single LAA SCELL. The present invention can include both of these cases. When an HARQ-ACK transmission is performed on a UL-by-group basis, an unlicensed carrier capable of transmitting HARQ-ACKs depending on the channel availability based on channel access within a group, the LAA SCell index is dynamically changed on a subframe by subframe basis , Or it can be set semi-static to one unlicensed carrier, LAA SCELL. The base station receiving the feedback for HARQ-ACK (s) based on the group can set CW_p and group_index to update and adapt to CW_p and group_index by managing CW_p and group_index for the DL PDSCH transmitted to the UE based on the group. group of the DL PDSCH (s) on the LAA Scell (s) set as the group.

(When HARQ-ACK for the PDSCH (s) transmitted on the DL on the unlicensed carrier is divided into UL on the licensed carrier and UL on the unlicensed carrier)

If the HARQ-ACK feedback for the PDSCHs transmitted on the unlicensed carrier, LAA Scell is divided into the UL on the licensed carrier, the PUCCH or the PUSCH on the unlicensed carrier, and the UL PUCCH or the PUSCH on the unlicensed carrier, The CW update and adaptation according to the ACK feedback is performed when the feedback which is regarded as a NACK is Z% or more based on Z% of the NACK (eg, 80 or 50, which may be a natural number value set by the base station) set it to doubling, otherwise set CW to reset. When the HARQ-ACK feedback is transmitted on the licensed carrier during the HARQ-ACK feedback for the PDSCHs transmitted to the LAA Cell, the CW for the LAA SCell for transmitting the PDSCH corresponding to the HARQ-ACK transmitted on the licensed carrier, A method of adjusting CWS as the corresponding combination for methods A-1, A-2, A-3, A-4 and B-1, B-2, B-3 as CW update and adaptation as described in the invention is used . Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

The CW update and adaptation according to the HARQ-ACK feedback transmitted on the unlicensed carrier on the UL is performed when the HARQ-ACK for the PDSCH (s) transmitted on the DL on the LAA Scell is transmitted on the unlicensed carrier, The CW update and adaptation for the PDSCH transmitted on the LAA SCell by applying the same method as that of the method 100 of the present invention by limiting the group to the LAA Scell that transmits the PDSCH corresponding to the HARQ- It can be used as a method. Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

Unlike the method of updating or adapting CW according to whether each cell transmitting HARQ-ACK independently is an unlicensed cell, LAA SCELL or licensed cell, HARQ-ACK feedback on a licensed carrier and HARQ-ACK feedback on an unlicensed carrier A method of managing the contention window for the LBT of the DL PDSCH transmission on the unlicensed carrier, LAA Scell, can also be considered. This is a hybrid method according to the method 100 and the method 110, and the conditions according to the methods 100 and 110, that is, the condition -100. When ACK detection is performed in the base station as a feedback value transmitted on the unlicensed carrier to the UL, the condition -110. If feedback considered as a NACK is not equal to or more than Z%, it is possible to set CW to be reset when both condition -100 and condition -110 are satisfied, and to set CW to doubling if both are not satisfied. Alternatively, considering that the condition 100 considers UL transmission on the unlicensed carrier, it may be considered that the channel condition of the unlicensed carrrier can be better reflected, and a method of resetting or doubling the CW according to whether the condition 100 is satisfied may be considered have. In contrast, the condition -110, which is designed to better reflect the channel state of all UEs, is considered to better reflect the channel status of unlicensed carriers in all UEs, and CW is reset according to whether condition -110 is satisfied a method of doubling may be considered. Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

In the LTE system up to the existing Rel-13, if simultaneous transmission of PUSCH and PUCCH is configured in the UE, simultaneous transmission of PUSCH and PUCCH can be performed in the same carrier or between different carriers. However, if simultaneous transmission of PUSCH and PUCCH is not configured in the UE, transmission of UCI (uplink control information) such as HARQ-ACK and CSI is performed on the PUCCH when transmission of the PUSCH is not scheduled in the corresponding subframe , Transmission of UCI (uplink control information) such as HARQ-ACK and CSI to be transmitted to the PUCCH is piggybacked to the PUSCH and transmission of the PUSCH having the UCI is performed only if transmission of the PUSCH is scheduled in the corresponding subframe . This applies equally to different carriers even when carrier aggregation is performed.

In the present invention, in the case where different carriers are composed of licensed carriers and unlicensed carrers in performing carrier aggregation, one cell group capable of transmitting a PUCCH is composed of a licensed carrier (s) and an unlicensed carrier (s) ,

- If simultaneous transmission of PUSCH and PUCCH is configured to UE, HARQ-ACK and CSI as UE feedback for DL transmission to licensed carriers can be transmitted to PUCCH on licensed carrier, but for HARQ-ACK it is not possible to transmit to the scheduled PUSCH on the unlicensed carrier, and the CSI (periodic CSI or aperiodic CSI) can be transmitted on the unlicensed carrier on the scheduled PUSCH. Also, HARQ-ACK and CSI as UE feedback for DL transmission transmitted to unlicensed carriers may be transmitted to the PUCCH on the licensed carrier, or may be transmitted to the corresponding PUSCH if the PUSCH on the unlicensed carrier is scheduled.

However, if concurrent transmission of PUSCH and PUCCH is not configured to the UE, HARQ-ACK and CSI as UE feedback for DL transmission transmitted to licensed carriers may be transmitted to the PUCCH on the licensed carrier, but HARQ-ACK Can not be transmitted to the scheduled PUSCH on the unlicensed carrier, and CSI (periodic CSI or aperiodic CSI) can be transmitted on the unlicensed carrier on the scheduled PUSCH. According to the method used in the existing LTE system, when the PUSCH is not scheduled in the corresponding subframe, the UE feedback for the DL transmission on the licensed carrier by the PUCCH on the licensed carrier, the feedback of the UE for the DL transmission on the HARQ-ACK, CSI and unlicensed carrier If the PUSCH is scheduled on the licensed carrier or in the corresponding subframe on the unlicensed carrier, the HARQ-ACK and the CSI are transmitted on the PUCCH on the licensed carrier. As UE feedback for UE, piggybacking HARQ-ACK and CSI as UE feedback for HARQ-ACK, CSI and DL transmission on unlicensed carrier, only the PUSCH that is scheduled is transmitted. However, since HARQ-ACK as UE feedback for DL transmission transmitted on the licensed carrier is set so that it can not be transmitted on the unlicensed carrier, when the PUSCH is scheduled on the unlicensed carrier, It is impossible to transmit the HARQ-ACK response as the UE feedback to the scheduled PUSCH on the unlicensed carrier. Therefore, the present invention will be described with reference to the following embodiments.

1. In one embodiment, a CA is composed of a licensed carrier (s) and an unlicensed carrier (s) as a cell group capable of transmitting a PUCCH in the case where the configuration of a CA is composed of licensed carriers and unlicensed carrers. And the PUCCH are not configured in the UE, the UE does not expect the PUSCH transmission to be scheduled on the unlicensed carrier from the base station on the corresponding subframe where the PUCCH can be transmitted, and the UE assumes only the transmission of the PUCCH ACK, CSI and HARQ-ACK and CSI as UE feedback for DL transmission on unlicensed carrier as PUCCH on the licensed carrier as UE feedback for DL transmission on the licensed carrier.

2. In another embodiment, in the case where the configuration of CA is composed of licensed carriers and unlicensed carrers, it is composed of a licensed carrier (s) and unlicensed carrier (s) as a cell group capable of transmitting PUCCH, And PUCCH are not configured in the UE, an HARQ-ACK response is transmitted as UE feedback for DL transmission on the licensed carrier as UE feedback to be transmitted on the corresponding subframe on which the PUCCH can be transmitted The UE does not expect the PUSCH transmission to be scheduled on the unlicensed carrier from the base station, and the UE assumes only the transmission of the PUCCH and transmits the HARQ-ACK and CSI as the UE feedback for the DL transmission on the licensed carrier to the PUCCH on the licensed carrier And UE feedback for DL transmission on unlicensed carrier, it is possible to transmit HARQ-ACK, CSI to PUCCH on licensed carrier Set to. Since only the HARQ-ACK response to the DL transmission on the licensed carrier can be transmitted to the PUSCH on the unlicensed carrier, the CSI can be transmitted to the PUSCH on the unlicensed carrier. Therefore, only when the UCI type to be piggybacked is the HARQ-ACK response for the DL transmission on the licensed carrier, the method is applied.

3. In another embodiment, if the PUCCH is composed of a licensed carrier (s) and an unlicensed carrier (s) as one cell group capable of transmitting PUCCH and the simultaneous transmission of PUSCH and PUCCH is not configured in the UE, When the PUSCH transmission is scheduled on the unlicensed carrier from the base station on the corresponding subframe, the UCI piggyback method used in the legacy may be used to transmit the UE feedback for the DL transmission on the licensed carrier to the PUSCH on the unlicensed carrier As HARQ-ACK, CSI, and UE feedback for DL transmission on an unlicensed carrier, HARQ-ACK and CSI can be transmitted on a unicensed carrier PUSCH.

o 4. In another embodiment, if the PUCCH is composed of a licensed carrier (s) and an unlicensed carrier (s) as one cell group capable of transmitting PUCCH, and the simultaneous transmission of PUSCH and PUCCH is not configured in the UE, When the PUSCH transmission is scheduled on the unlicensed carrier from the base station on the corresponding subframe on which the transmission can be performed, the UE drops the scheduled PUSCH on the unlicensed carrier and the UE assumes only the PUCCH transmission and transmits the PUCCH on the licensed carrier UE feedback for DL transmission on the licensed carrier is set so that HARQ-ACK and CSI can be transmitted on the PUCCH on the licensed carrier as UE feedback for HARQ-ACK, CSI and DL transmission on the unlicensed carrier.

5. In another embodiment, if the PUCCH is composed of a licensed carrier (s) and an unlicensed carrier (s) as one cell group capable of transmitting PUCCH and the simultaneous transmission of PUSCH and PUCCH is not configured in the UE, the PUCCH The UE transmits the HARQ-ACK response as the UE feedback for the DL transmission on the licensed carrier as the UE feedback to be transmitted by the UE when the PUSCH transmission is scheduled on the unlicensed carrier from the base station on the corresponding subframe , The UE drops the scheduled PUSCH on the unlicensed carrier only. In this case, the UE assumes only the transmission of the PUCCH and transmits the HARQ-ACK, the CSI, and the DL transmission on the unlicensed carrier as the UE feedback for the DL transmission on the licensed carrier with the PUCCH on the licensed carrier. And sets HARQ-ACK and CSI as PUCCH on the licensed carrier as feedback for the UE. Since only the HARQ-ACK response to the DL transmission on the licensed carrier can be transmitted to the PUSCH on the unlicensed carrier, the CSI can be transmitted to the PUSCH on the unlicensed carrier. Therefore, only when the UCI type to be piggybacked is the HARQ-ACK response for the DL transmission on the licensed carrier, the method can be applied to drop the scheduled PUSCH on the unlicensed carrier.

&Lt; Exclusion method for calculating NACK ratio for PUSCH transmission drop at CWS adaptation >

4 and 5, when the PUSCH is scheduled from the base station but the PUSCH is dropped from the terminal, in the case of using the contention window size adaptation based on the PUSCH reception of the base station in the UL LBT, case, the base station knows the PUSCH dropping from the terminal according to the combination of the corresponding configuration information. Therefore, for the PUSCH dropping from the terminal, the PUSCH dropping at the time of CWS adaptation may be used for collision handling or interference status in the unlicensed carrier The dropped PUSCH can be set not to be used when calculating the NACK ratio of the CWS adaptation or when Z% of the NACK used in the DL CWS adaptation is used.

The expression for the unlicensed carrier (s) in the present invention may be the same as that for the LAA Scell (s).

The present invention relates to a method for transmitting UCI (including A / N and CSI) to a PUSCH on an unlicensed band or unlicensed carrier or LAA Scell, or a HARQ-ACK transmission on a PUSCH on an unlicensed band or unlicensed carrier or LAA Scell To the UL LBT method.

As a method for setting up UCI (including A / N and CSI) in the PUSCH of the LAA SCell, a UCI cell group composed only of LAA SCELL is defined in the case of self-carrier scheduling, The UCI including at least the HARQ-ACK (s) for the PDSCH transmitted in the related cell group can be set to the UE to be transmitted on the scheduled PUSCH.

The following describes the operation under the assumption of the scheduled PUSCH when the UCI cell group is configured in the UE. However, when the UCI cell group is not configured in the UE, the BS instructs the specific unlicensed carrier or the LAA SCELL or the eNB the following operations may be possible even under the assumption of using the method of transmitting the corresponding UCI in the UL subframe for triggering.

FIG. 27 is a diagram illustrating a case where uplink transmission is performed after LBT success of a PUSCH configured to transmit UCI or A / N. 27- (a) shows a case where the gap for the LBT is on the symbol (s) preceding the PUSCH subframe. Fig. 27- (b) shows a case where the gap for the LBT is on the symbol Respectively.

In FIG. 27- (a), if the corresponding UL subframe scheduled for PUSCH is a subframe configured to transmit UCI, UCI (including A / N and CSI) is transmitted to the PUSCH of the unlicensed band or unlicensed carrier or LAA Scell The following three methods can be considered as a method for setting up the HARQ-ACK transmission to be allowed to the HARQ-ACK transmission on the license-exempt band or unlicensed carrier or the LAA Scell PUSCH.

1) Fixed codebook size to feedback all configured HARQ processes within within a group and with triggering: All HARQ-ACK feedback of group or carrier configured by triggering by eNB is transmitted in UL subframe triggering eNB , The UE transmits triggering information to enable the eNB to transmit UCI or HARQ-ACK on the control channel (UL grant and DL grant), and when the UE receives the control channel, it transmits UCI or HARQ- ACK can be transmitted.

2) Transmission of HARQ-ACKs According to the HARQ-ACK timing defined in CA / LAA of Rel-13, For example, in the case of FDD, the HARQ-ACK feedback timing for transmission to PDSCH in subframe #n is set to be transmitted in subframe # n + 4, and in TDD, it is defined separately in Rel-13 spec. ) HARQ-ACKs and fails to transmit HARQ-ACKs due to LBT failure in a UL subframe configured to transmit HARQ-ACKs, the HARQ-ACKs are deferred to the corresponding HARQ-ACKs.

3) Transmission of HARQ-ACKs in accordance with the HARQ-ACK timing defined in the CA / LAA of Rel-13. For example, in the case of FDD, the HARQ-ACK feedback timing for transmission to PDSCH in subframe #n is set to be transmitted in subframe # n + 4, and in TDD, it is defined separately in Rel-13 spec. ) HARQ-ACKs and does not transmit HARQ-ACKs due to LBT failure in a UL subframe configured to transmit HARQ-ACKs, the HARQ-ACKs are further deferred to be transmitted to the corresponding HARQ-ACKs. For example, PUSCH scheduled UL subframe, or on an unlicensed carrier PUCCH or PUSCH on a subframe to be transmitted to the next UL based on the timing of an LBT failed UL subframe on an unlicensed carrier To, or may be based on the timing of the LBT failed UL subframe on the unlicensed carrier and then to transmit the deferred HARQ-ACKs as a PUCCH or a PUSCH on the licensed carrier.

If the BS can not perform the UL transmission due to the LBT failure on the subframe intended to transmit UL to the UE from the above 1), 2), and 3) methods, retransmission for data transmission is performed for the transmission of the PUSCH It is possible to perform retransmission according to the procedure, but there is no procedure for performing retransmission for UCI transmission such as A / N, and in case of A / N, latency for the corresponding downlink transmission is increased So that the data rate of the downlink may be greatly reduced.

FIG. 28 is a diagram illustrating a case where uplink transmission can not be performed due to LBT failure of a PUSCH configured to transmit UCI or A / N. FIG. 28- (a) shows a case where the gap for the LBT is on the symbol (s) in front of the PUSCH subframe. FIG. 28- (b) Respectively.

This is because the PUSCH can not be performed due to the LBT failure on the PUSCH on the UL subframe that is scheduled to transmit UCI or A / N, so that the transmission of UCI and A / N set to be transmitted can not be performed .

Therefore, when the UCI (including A / N and CSI) is set to be able to transmit UCI (including A / N and CSI) to the PUSCH of the unlicensed band or unlicensed carrier or LAA Scell, A method for enabling transmission through an independent LBT is explained. In addition, when HARQ-ACK transmission is set to be performed on the PUSCH of the unlicensed band or the unlicensed carrier or the LAA Scell, the HARQ-ACK can be transmitted through the LBT independent of the LBT of the PUSCH .

This is because it is not possible to perform the PUSCH transmission due to the one-stage LBT failure by performing the LBT in the two-stage terminal on the PUSCH on the UL subframe scheduled to transmit UCI or A / N, And the transmission of the A / N can not be performed.

29- (a) and (b) illustrate one embodiment of the present invention. In the PUSCH configured to transmit UCI or A / N, one LBT is performed at the LBT point of the PUSCH and the A / N can be transmitted And performing CCA with a single sensing interval at the symbol position of the SC-FDMA.

As shown in FIG. 29, after the LBT is performed by the base station and the UE for the PUSCH, an A / N transmission startable SC-FDMA symbol to enable transmission of UCI or A / N in case of LBT failure a method may be considered in which the CCA is once again performed immediately before the index # 2 during a single sensing interval (for example, 16us, 25us, 34us, or 43us). If the CCA of the corresponding single sensing interval is successful, the UE may transmit the UCI or the A / N with the transmission of the UL DMRS. If two LBTs fail, do not perform PUSCH and UCI or A / N transmissions.

30- (a) and 30 (b) illustrate another embodiment of the present invention, in which a LBT is performed at a LBT point of a PUSCH and an A / N is transmitted for a PUSCH configured to transmit UCI or A / N FIG. 4 is a diagram illustrating a case of performing LBT in two stages in which CCA having a single sensing interval is performed at symbol positions of a slot-based SC-FDMA in a slot.

30, in the case of LBT failure after performing the LBT intended by the base station and the UE for the PUSCH, during a single sensing interval (for example, 16us, 25) to enable transmission of UCI or A / N in case of LBT failure us, 34us, or 43us) slot can be considered. To perform a single LBT at the LBT point of the PUSCH and perform CCA with a single sensing interval at the symbol position of the SC-FDMA capable of transmitting A / N, considering slot-based UCI mapping or A / N mapping It is a method to set UCI or A / N transmission to be possible when CCA with single sensing interval in second slot succeeds even if CCA with single sensing interval in first slot fails on UL subframe. If the CCA of single sensing interval in the first slot is successful, the UE can make UCI or A / N transmission together with transmission of UL DMRS in two slots. Or, it can be configured to guarantee transmission of UCI or A / N in each slot based on CCA of single sensing interval in each slot. In addition to the failure of the LBT for the PUSCH, if the slot-based LBT also fails, the PUSCH and the UCI or A / N are not transmitted.

31- (a) and 31 (b) illustrate a case of performing two-stage LBT at the LBT point of the PUSCH with respect to the PUSCH configured to transmit UCI or A / N as another embodiment of the present invention.

As shown in FIG. 31, in the case of LBT failure after performing the LBT intended by the base station and the UE for the PUSCH, during a single sensing interval (for example, 16us, 25 us, 34us, or 43us) may be considered. If the CCA of the corresponding single sensing interval is successful, the UE shall perform transmission of UCI or A / N. However, in FIG. 31, the method of setting the PUSCH to be transmitted after the success of the CCA having the single sensing interval is expressed, but since the LBT for the PUSCH has failed, resource mapping for the PUSCH is not performed for the corresponding PUSCH And it is possible to transmit only UCI or A / N and UL DMRS.

29, 30 and 31, when the PUSCH resource can not be transmitted, the timing of the CCA having a single sensing interval and the time gap between the UCI or A / N transmission and the timing of the UL DMRS or the time gap between the slots occur The SC-FDMA symbol on the UL subframe in which the UCI or the A / N is not transmitted may not be allocated to the corresponding PUSCH resource because the channel opportunity may be lost due to the channel idle from other nodes in the middle of the corresponding UL subframe. A method of transmitting an arbitrary reservation signal may be additionally considered.

As to the LBT of the two-stage terminal according to the present invention, since there is no way to recognize whether the LBT is successful or failed according to the channel status of the terminal on the UL subframe intended to be transmitted to the terminal, Since the UCI and the A / N that are intended to be transmitted are always set to perform decoding, it is possible to improve the performance of the system by performing transmission in the situation of the channel where the transmission can be maximized in the terminal. As the UE performs additional LBT through the two-stage LBT, the complexity due to UCI and A / N decoding that may occur to the base station does not increase. Also, by using the present invention, the BS performs UCI or HARQ-ACK (s) decoding on a UL subframe intended to be transmitted from the UE, thereby causing a large latency for downlink transmission and a problem of significantly degrading the downlink data rate I can solve the problem that I can do.

The present invention relates to a two stage grant based eNB triggered HARQ-ACK (or UCI) transmission method.

First, we explain the necessity and method of UL transmission using two stage grant. If only the UL grant is triggered in the transmission burst under the condition that the minimum scheduling delay between UL grant and UL transmission is kept at 4 ms, the number of usable subframes that can perform UL transmission may be limited. For example, , It is limited to 2ms for UL transmission and 4ms or 6ms for UL transmission when MCOT is 8ms or 10ms. This can have a significant impact on the UL transmission of the LAA, especially since it only transmits limited UL transmissions in UL heavy traffic scenarios. Therefore, a method of using UL transmission using two stage grants as shown in FIG. 32 can be considered.

Referring to FIG. 32, the first grant transmitted through the DL transmitted in the preceding MCOT at least 4 ms prior informs all the scheduling information and the LBT parameters of the UL subframe (s) to be scheduled, but excludes accurate scheduling timing information And let them know. The UL subframe (s) scheduled in the current MCOT is triggered by the transmission of the second grant from the eNB and the second grant informs the actual transmission timing. The transmission timing may be less than 4ms and may have a value of 1ms or 2ms or 3ms.

In the HARQ-ACK transmission method based on eNB triggering using one stage grant, when a UL subframe to be transmitted by an UL grant exists outside the MCOT, a UL PUSCH including a HARQ-ACK (or UCI) The cat-4 LBT that performs a backoff in the UL subframe for transmission must be performed and transmitted. In this case, when performing cat-4 LBT, it is necessary to perform back-off based on the contention, so there is a high possibility of missing the opportunity to transmit to the corresponding UL subframe. In particular, since the LBT is performed using only one or two symbols before and after the UL subframe, there is a high probability that the UL PUSCH including the HARQ-ACK (or UCI) can not be transmitted in the subframe timing of the corresponding base station. Therefore, the present invention proposes a transmission method of HARQ-ACK (or UCI) to the PUSCH using two stage grant. In other words, the first grant transmitted through the DL transmitted in the preceding MCOT at least 4 ms earlier informs all the scheduling information and the LBT parameters of the UL subframe (s) to be scheduled, but not the accurate scheduling timing information do. The UL subframe (s) scheduled in the current MCOT is triggered by the transmission of the second grant from the eNB and the second grant informs the actual transmission timing. The transmission timing may be less than 4ms and may have a value of 1ms or 2ms or 3ms. At this time, in the second grant, the base station transmits HARQ-ACK (or UCI) including HARQ-ACK (or UCI) triggering information so as to transmit the HARQ-ACK (or UCI) to be transmitted to the PUSCH that has been scheduled. It is possible to inform HARQ-ACK (s) (or UCI) to be transmitted to the PUSCH at a certain subframe timing through the timing information transmitted by the second grant.

The method of transmitting the HARQ-ACK (or UCI) to the PUSCH using the two stage grant is a fast LBT method for the UL transmission in the newly configurable MCOT due to the DL transmission by the second grant For example, when the HARQ-ACK (or UCI) is scheduled to be transmitted on the PUSCH because it can be configured to perform only the CCA of 16us, 25us, 34us, or 43us and transmit using the No LBT in 16us it has an advantage that the probability of PUSCH LBT success and transmission possibility by fast LBT and No LBT can be increased. That is, it is possible to improve the performance of the system by lowering the probability that the HARQ-ACK (or UCI) can be dropped.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (1)

Uplink channels for license - exempt band communication, signal access method and multiplexing method, apparatus and system.

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