KR20130125005A - Apparatus and method for discontinuous reception in multiple component carrier system - Google Patents

Abstract

The present invention relates to a discontinuous reception apparatus in a multiple component carrier system and a method. In the present specification, A DRX method includes a step for receiving DRX composition information including parameters about the DRX operation from a base station, a step for starting a timer, a step for monitoring a physical downward link control channel transmitted from the base station, and a step for increasing the value of the timer one by one when a PDCCH sub frame including the physical downward link control channel is formed in a serving cell determining the increase of the value of the timer. According to the present invention, the PDCCH sub frame is defined in each serving cell, and whether the increase of the continuous time timer vale is determined based on the PDCCH sub frame defined in each serving cell level. The operation method of the DRX timer becomes clear. [Reference numerals] (S1300) Receive DRX construction information;(S1305) Operate a timer;(S1310) Monitor PDCCH;(S1315) Make a PDCCH sub-frame in a serving cell determining the increase of a timer value?;(S1320) Timer value increases by one;(S1325) Timer value = Expiration value?;(S1330) Timer expiration;(S1335) Receive a next PDCCH sub-frame

Description

Discontinuous reception apparatus and method in a multi-element carrier system {APPARATUS AND METHOD FOR DISCONTINUOUS RECEPTION IN MULTIPLE COMPONENT CARRIER SYSTEM}

The present invention relates to wireless communications, and more particularly, to an apparatus and method for discontinuous reception in a multi-component carrier system.

Radio resources used for wireless communication are generally defined in the frequency domain, time domain and code domain. In wireless communication, a user equipment (UE) and a base station (BS) should each use a given radio resource. The radio path transmitted by the terminal to the base station is called uplink, and the radio path transmitted by the base station to the terminal is called downlink. On the other hand, a radio resource used for downlink transmission and a radio resource used for uplink transmission are required to be distinguished so as not to overlap, such a method is called duplex (duplex).

As in the multiple access scheme for distinguishing different users, the uplink and the downlink can be distinguished in the frequency, time, and code domains. The duplex method is largely divided into a frequency division duplex (FDD) method for dividing uplink and downlink into frequency and a time division duplex (TDD) method for dividing uplink and downlink into time. The TDD scheme is one of half-duplex schemes in which only uni-directional communication is allowed.

In the FDD scheme, since uplink and downlink are distinguished in the frequency domain, data transmission between the base station and the terminal may be continuously performed in the time domain on each link. The FDD scheme is symmetrically allocating frequencies for uplink and downlink, and thus has been frequently used for symmetric services such as voice calls. As the method is suitable, research on this is being actively conducted.

Since the TDD scheme can allocate different time slots for uplink and downlink, the TDD scheme is suitable for asymmetric services. Another advantage of the TDD scheme is that uplink and downlink are transmitted and received in the same frequency band, and thus the channel state of the uplink and downlink is almost identical. Therefore, the channel state can be estimated immediately upon receiving the signal, which is suitable for array antenna technology. In the TDD scheme, the entire frequency band is used as an uplink or a downlink, but the uplink and the downlink are distinguished in the time domain. Data transmission and reception between the base station and the terminal can not be made at the same time.

A multiple component carrier system refers to a wireless communication system capable of supporting carrier aggregation. Carrier aggregation is a technique for efficiently using fragmented small bands in order to combine physically non-continuous bands in the frequency domain and to have the same effect as using logically large bands. Multi-element carrier systems support multiple component carriers (CCs) that are distinct in the frequency domain. The element carrier includes an uplink element carrier used in the uplink and a downlink element carrier used in the downlink. A DL serving as a serving cell may be formed by combining a downlink component carrier and an uplink component carrier. Or one serving cell may be composed of only the downlink component carrier.

In the TDD scheme, when serving cells of the same band (intra-band) are aggregated, the same uplink / downlink configuration is allocated to each serving cell. This is to prevent a problem in which interference occurs between serving cells when different uplink / downlink configurations are allocated because the frequency intervals are close between serving cells in the same band. On the other hand, when serving cells of different bands (inter-band) are aggregated, each serving cell may be assigned a different TDD uplink / downlink configuration. Accordingly, any subframe may be an uplink subframe for the first serving cell but a downlink subframe for the second serving cell.

It is not yet determined how the discontinuous reception operation is performed in the multi-component carrier system.

An object of the present invention is to provide an apparatus and method for discontinuous reception in a multi-component carrier system.

Another technical problem of the present invention is to provide a reference for counting an active time when a plurality of serving cells are configured in a terminal.

Another technical problem of the present invention is to provide an apparatus and method for performing a discontinuous reception operation based on the concept of a PDCCH subframe defined in terms of a plurality of serving cells.

According to an aspect of the present invention, there is provided a discontinuous reception (DRX) method by a terminal in a time division duplex (TDD) based multi-component carrier system. The method includes receiving DRX configuration information including a parameter related to a DRX operation from a base station, starting the timer when a timer starting condition is satisfied, during an active time in which the timer is ongoing, Monitoring a physical downlink control channel transmitted from the base station; and a PDCCH subframe including the physical downlink control channel is configured in a serving cell for determining an increase in the value of the timer. If so, increasing the value of the timer by one.

According to another aspect of the present invention, a terminal for performing a DRX operation in a time division duplex based multi-component carrier system. The terminal receives a DRX configuration information including a parameter related to the DRX operation from the base station, and if the start condition of the timer is met, the timer is started, the physical transmitted from the base station during the active time of the timer DRX operation control unit for monitoring the downlink control channel.

The DRX operation controller increases the value of the timer by 1 when a PDCCH subframe including the physical downlink control channel is configured in a serving cell that determines the increase of the value of the timer. You can not change the value of the timer.

By defining a PDCCH subframe at each serving cell level and determining whether the duration timer value is increased based on the PDCCH subframe defined at each serving cell level, an operation method of the DRX timer can be clarified.

1 shows a wireless communication system to which the present invention is applied.
2 is another example of a radio frame structure to which the present invention is applied.
FIG. 3 is a diagram illustrating states of serving cells configured in a terminal in a multi-component carrier system according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram showing a difference in TDD uplink / downlink configuration between serving cells when inter-band carrier aggregation is performed according to an embodiment of the present invention.
5 is an explanatory diagram for explaining a DRX operation to which the present invention is applied.
6 is an exemplary diagram in which a duration timer according to an embodiment of the present invention operates.
7 is an exemplary diagram in which a duration timer according to another embodiment of the present invention operates.
8 is an exemplary diagram in which a duration timer according to another embodiment of the present invention operates.
9 is an exemplary diagram in which a DRX inactivity timer operates according to an embodiment of the present invention.
10 is an exemplary diagram in which a DRX retransmission timer operates according to an embodiment of the present invention.
11 is an exemplary diagram in which a DRX retransmission timer operates according to another example of the present invention.
12 is a signaling flowchart between a terminal and a base station for a DRX operation according to an embodiment of the present invention.
13 is a flowchart illustrating a DRX operation by a terminal according to an embodiment of the present invention.
14 is a flowchart illustrating a DRX operation by a terminal according to another example of the present invention.
15 is a flowchart illustrating a DRX operation by a base station according to an embodiment of the present invention.
16 is a block diagram of a terminal and a base station performing a DRX operation according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

According to embodiments of the present invention, 'transmitting a control channel' can be interpreted as meaning that control information is transmitted through a specific channel. Here, the control channel may be, for example, a physical downlink control channel (PDCCH) or a physical uplink control channel (PUCCH).

1 shows a wireless communication system to which the present invention is applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system 10 includes at least one base station 11 (BS). Each base station 11 provides communication services to specific cells (15a, 15b, 15c). The cell may again be divided into multiple regions (referred to as sectors). The base station 11 may be called by other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, a femto base station, a home node B, . Cells are meant to cover various coverage areas such as megacell, macrocell, microcell, picocell, and femtocell.

A user equipment (UE) 12 may be fixed or mobile and may be a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like.

Hereinafter, the downlink refers to a transmission link from the base station 11 to the terminal 12, and the uplink refers to a transmission link from the terminal 12 to the base station 11 it means. In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11. There are no restrictions on multiple access schemes applied to wireless communication systems. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA , OFDM-CDMA, and the like. A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

Carrier aggregation (CA) is a communication scheme in which a plurality of carriers are supported, also referred to as spectrum aggregation or bandwidth aggregation. Individual unit carriers bound by carrier aggregation are called component carriers (CCs). Each element carrier is defined as the bandwidth and center frequency. Carrier aggregation is introduced to support increased throughput, prevent cost increases due to the introduction of wideband radio frequency (RF) devices, and ensure compatibility with existing systems. For example, if five elementary carriers are allocated as the granularity of a carrier unit having a bandwidth of 20 MHz, it can support a bandwidth of up to 100 MHz.

Carrier aggregation can be divided into contiguous carrier aggregation between successive element carriers in the frequency domain and non-contiguous carrier aggregation between discontinuous element carriers. The number of carriers aggregated between the downlink and the uplink may be set differently. The case where the number of downlink element carriers is equal to the number of uplink element carriers is referred to as symmetric aggregation and the case where the number of downlink element carriers is different is referred to as asymmetric aggregation.

The size (i.e. bandwidth) of the element carriers may be different. For example, if five element carriers are used for a 70 MHz band configuration, then 5 MHz element carrier (carrier # 0) + 20 MHz element carrier (carrier # 1) + 20 MHz element carrier (carrier # 2) + 20 MHz element carrier (carrier # 3) + 5 MHz element carrier (carrier # 4).

Hereinafter, the multi-component carrier system refers to a system supporting carrier aggregation. In a multi-carrier system, adjacent carrier aggregation and / or non-adjacent carrier aggregation may be used, and either symmetric aggregation or asymmetric aggregation may be used. The serving cell may be defined as an element frequency band that may be aggregated by carrier aggregation based on a multiple component carrier system. The serving cell includes a primary serving cell (PCell) and a secondary serving cell (SCell). The primary serving cell refers to one serving cell that provides security input and NAS mobility information in an RRC connection or re-establishment state. Depending on the capabilities of the terminal, at least one cell may be configured to form a set of serving cells together with a main serving cell, said at least one cell being referred to as a secondary serving cell. The set of serving cells configured in one terminal may include only one main serving cell or may include one main serving cell and at least one secondary serving cell.

The primary serving cell is always activated, while the secondary serving cell is a serving cell that is activated / deactivated according to a specific condition. The specific condition may be a case where an activation / deactivation indicator of the base station is received or an inactivation timer in the terminal expires. Activation means that the transmission or reception of traffic data is performed or is in a ready state. Deactivation means that transmission or reception of traffic data and control information for the traffic data is impossible, and measurement or transmission of minimum information is possible.

The downlink component carrier corresponding to the main serving cell is referred to as a downlink principal carrier (DL PCC), and the uplink component carrier corresponding to the main serving cell is referred to as an uplink principal carrier (UL PCC). In the downlink, the element carrier corresponding to the secondary serving cell is referred to as a downlink sub-element carrier (DL SCC), and in the uplink, an elementary carrier corresponding to the secondary serving cell is referred to as an uplink sub-element carrier (UL SCC) do. Only one DL serving carrier may correspond to one serving cell, and DL CC and UL CC may correspond to each other.

2 is another example of a radio frame structure to which the present invention is applied. This is a TDD radio frame structure.

Referring to FIG. 2, a radio frame includes two half-frames. Each half frame has the same structure. The half frame includes five subframes and three fields Downlink Pilot Time Slot (DwPTS), Guard Period, and Uplink Pilot Time Slot (UpPTS). The DwPTS is used for initial cell search, synchronization, or channel estimation in the UE. UpPTS is used to match the channel estimation at the base station and the uplink transmission synchronization of the terminal. The guard interval is a period for eliminating the interference occurring in the uplink due to the multi-path delay of the downlink signal between the uplink and the downlink.

Table 1 shows an example of a TDD UL / DL configuration of a radio frame. The TDD uplink / downlink configuration defines a subframe reserved for uplink transmission and a subframe reserved for downlink transmission in one radio frame. That is, the TDD uplink / downlink configuration indicates which rules are allocated (or reserved) to uplink and downlink in all subframes in one radio frame.

Uplink / Downlink Configuration Conversion point cycle
Sub-frame number 0 One 2 3 4 5 6 7 8 9 0 5 ms D S U U U D S U U U One 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D

Referring to Table 1, 'D' indicates that the subframe is used for downlink transmission, and 'U' indicates that the subframe is used for uplink transmission. 'S' is a special subframe, and indicates that the subframe is used for a special purpose, and is used for frame synchronization or downlink transmission. Hereinafter, a subframe allocated for downlink transmission is simply called a downlink subframe, and a subframe allocated for uplink transmission is simply called a downlink subframe. Each TDD uplink / downlink configuration has a different position and number of downlink subframes and uplink subframes in one radio frame.

The point of time when the downlink is changed to the uplink or the time when the uplink is switched to the downlink is referred to as a switching point. The switch-point periodicity means a period in which an uplink subframe and a downlink subframe are repeatedly switched in the same manner, and are 5 ms or 10 ms. For example, in the TDD uplink / downlink configuration 0, D-> S-> U-> U-> U is switched from the 0th to the 4th subframe, and the 5th to 9th subframe is the same as before. Similarly, it switches to D-> S-> U-> U-> U. Since one subframe is 1ms, the periodicity at the switching time is 5ms. That is, the periodicity of the switching time is less than one radio frame length (10ms), and the switching mode in the radio frame is repeated once.

The TDD uplink / downlink configuration of Table 1 may be transmitted from the base station to the terminal through system information. The base station may inform the terminal of the change of the uplink-downlink allocation state of the radio frame by transmitting only the index of the TDD uplink / downlink configuration whenever the TDD uplink / downlink configuration is changed. Alternatively, the TDD uplink / downlink configuration may be control information that is commonly transmitted to all terminals in a cell through a broadcast channel as broadcast information.

The multi-component carrier system operates a plurality of serving cells such as a main serving cell and / or a secondary serving cell. The TDD uplink / downlink configuration of the main serving cell defines an uplink subframe and a downlink subframe of the main serving cell. The TDD uplink / downlink configuration of the secondary serving cell defines an uplink subframe and a downlink subframe of the secondary serving cell. Therefore, a plurality of serving cells configured in the terminal may take the TDD uplink / downlink configuration independently. This may be referred to as a cell-specific TDD configuration. For example, in Table 1, the TDD uplink / downlink configuration of the primary serving cell is number 2, and the TDD uplink / downlink configuration of the secondary serving cell is number 5. In this case, subframe 7 is an uplink subframe for the main serving cell and a downlink subframe for the secondary serving cell.

FIG. 3 is a diagram illustrating states of serving cells configured in a terminal in a multi-component carrier system according to an embodiment of the present invention.

Referring to FIG. 3, the system bandwidth includes bands A and B, band A includes a main serving cell (PCell) and a first secondary serving cell (SCell 1), and band B includes a second secondary serving. It includes a cell (SCell 2) and a third secondary serving cell (SCell 3). Carrier aggregation of the primary serving cell and the first secondary serving cell is intra-band aggregation. Similarly, the carrier aggregation of the second secondary serving cell and the third secondary serving cell is the aggregation in the B band. On the other hand, the carrier aggregation of the first secondary serving cell and the secondary secondary serving cell or the carrier aggregation of the primary serving cell and the second secondary serving cell, or the carrier aggregation of the primary serving cell and the third secondary serving cell is inter-band. A) aggregation. Alternatively, carrier aggregation of the first secondary serving cell and the third secondary serving cell is also interband aggregation. When in-band aggregation, the serving cells in the same band should all have the same TDD uplink / downlink configuration, but when inter-band carrier aggregation, the serving cells in different bands may have different TDD uplink / downlink configurations. . Different TDD uplink / downlink configurations between serving cells have no problem in the full-duplex mode, but may be a problem in the half-duplex mode.

TDD uplink / downlink configuration between serving cells in interband aggregation may be necessary to avoid interference with other coexistent TDD systems such as TDS-CDMA or WiMAX in the same band. In addition, the TDD uplink / downlink configuration has many uplink subframes on the low frequency band, and the TDD uplink / downlink configuration has many downlink subframes on the high frequency band to help coverage expansion and peak. Affects peak throughput.

FIG. 4 is an explanatory diagram showing a difference in TDD uplink / downlink configuration between serving cells when inter-band carrier aggregation is performed according to an embodiment of the present invention. This is explained based on FIG. 3.

Referring to FIG. 4, the same TDD uplink / downlink configuration is applied between serving cells included in the same band, and the TDD uplink / downlink configuration is independently applied to different bands. Such a TDD uplink / downlink configuration is also called a band-specific TDD uplink / downlink configuration. For example, the TDD uplink / downlink configuration 0 is applied to both the primary serving cell and the first secondary serving cell included in the band A, and the second secondary serving cell and the third secondary serving cell included in the band B are both applied. TDD uplink / downlink configuration No. 1 is applied.

For example, when carrier aggregation is performed between the first secondary serving cell and the second secondary serving cell, interband carrier aggregation is achieved. Of course, the carrier aggregation of the primary serving cell and the second secondary serving cell, the carrier aggregation of the primary serving cell and the third secondary serving cell, and the carrier aggregation of the first secondary serving cell and the third secondary serving cell are also interband aggregation. Looking at the TDD uplink / downlink configuration of the first secondary serving cell and the second secondary serving cell, subframes 4 and 9 are uplink subframes in the first secondary serving cell, whereas downlinks are used in the second secondary serving cell. It is a subframe. Subframe conflict occurs in subframes 4 and 9 in the TDD uplink / downlink configuration. Subframe mismatch refers to a situation in which subframe transmission directions of two or more serving cells to be compared are different, and subframes 4 and 9 may be referred to as conflicting subframes.

Depending on the duplex mode, the UE operation for subframe mismatch is different. For example, in the all-duplex mode, the UE may perform uplink transmission on the first secondary serving cell in subframes 4 and 9 and perform downlink reception on the second secondary serving cell. On the other hand, in the half-duplex mode, since communication is possible in only one direction, the UE selects only one of the first secondary serving cell and the second secondary serving cell in subframe 4, and selects the selected secondary serving cell. Communicate with the base station via For example, the conflict subframe may be selected according to a TDD uplink / downlink configuration set as a reference. In this case, the base station may inform the terminal in advance of information on which link direction to perform communication in the conflict subframe.

Similarly, the UE selects only one of the first secondary serving cell and the second secondary serving cell in subframe 9 and performs communication with the base station through the selected secondary serving cell. Since the remaining subframes except for the 4th and 9th subframes are configured in the same direction, the UE may perform communication through all secondary serving cells without having to select any one serving cell.

The UE generates PDCCHs based on a cell-radio network temporary identifier (C-RNTI), transmission power control (PPC) -PUCCH-RNTI, TPC-PUSCH-RNTI and semi persistent scheduling (SPS) Monitoring can be performed. Monitoring of the PDCCH scrambled with one of the RNTIs can be controlled by the DRX operation, the parameters of the DRX is transmitted by the base station to the terminal by the RRC message. In addition to the RNTIs, the UE should always receive system information (SI) -RNTI, p (paging) -RNTI, etc. regardless of the configuration officer DRX operation by the RRC message. Here, the remaining PDCCHs other than the PDCCH scrambled with the C-RNTI are always received through the common search space of the main serving cell.

If the terminal has a DRX parameter configured in the RRC connected state, the terminal performs discontinuous monitoring on the PDCCH based on the DRX operation. On the other hand, if the DRX parameter is not configured, the UE performs continuous PDCCH monitoring. Discontinuous PDCCH monitoring may mean that the UE monitors the PDCCH only in a specific subframe, and continuous PDCCH monitoring may mean that the UE monitors the PDCCH in all subframes. On the other hand, when PDCCH monitoring is required in a DRX-independent operation such as a random access procedure, the UE monitors the PDCCH according to the requirements of the corresponding operation.

5 is an explanatory diagram for explaining a DRX operation to which the present invention is applied.

Referring to FIG. 5, the DRX operation is repeated in units of a DRX cycle (500). The DRX cycle 500 is a periodic repetition of an on duration 505 that follows an inactive section. Is defined. One cycle of the DRX cycle 500 includes a duration 505 and a DRX opportunity for DRX 510. The RRC layer manages several timers to control the DRX operation. The timers controlling the DRX operation include a duration timer (onDurationTimer), a DRX inactivity timer (drxInactivity Timer), and a DRX retransmission timer (drxRetransmission Timer).

Including the duration of the duration timer or the DRX inactivity timer or the DRX retransmission timer is called active time. Alternatively, the activity time may mean all sections in which the UE can monitor the PDCCH. When the DRX cycle 500 is configured, the activity time includes the duration of the duration timer or the DRX inactivity timer or the DRX retransmission timer. The terminal monitors the PDCCH for the PDCCH subframe (PDCCH subframe) during the active time.

DRX operation is performed on the serving cell configured and activated in the terminal. In addition, a single DRX operation is applied to all serving cells. That is, the DRX operation is not separately performed for each serving cell, but all the serving cells perform the DRX operation based on one DRX cycle, DRX parameter, and timer. Therefore, all serving cells configured and activated in the terminal have the same active time.

Other parameters to control DRX operation include long DRX cycle (longDRX-Cycle) and DRX start offset (drxStartOffset) .The base station can optionally set DRX short cycle timer (drxShortCycleTimer) and short DRX-cycle (shortDRX-Cycle). Can be. In addition, a HARQ round trip time (RTT) timer is defined for each downlink HARQ process.

The DRX start offset is a value defining the subframe in which the DRX cycle 500 begins. The DRX short cycle timer is a timer that defines the number of consecutive subframes for which the UE must follow a short DRX cycle. The HARQ RTT timer is a timer that defines the minimum number of subframes before the interval in which downlink HARQ retransmission is expected by the UE.

In a wireless communication system operating a plurality of CCs, the fact that a UE may have a different TDD uplink / downlink configuration for each serving cell may not only cause the aforementioned conflict subframe problem but also affect DRX operation. Crazy Therefore, an operation criterion for each timer configured by the base station for DRX operation should be clearly defined. Accordingly, various embodiments of the operation criteria of the duration timers, the DRX inactivity timer, and the DRX retransmission timer, which are timers that are counted based on the number of subframes in the DRX operation, are disclosed.

First, the definition of the PDCCH subframe.

In a single carrier system, a PDCCH subframe may be defined as a subframe including a PDCCH. Accordingly, the downlink subframe may be included in the PDCCH subframe in the TDD scheme. In addition, a special subframe including the DwPTS period may also be included in the PDCCH subframe. On the other hand, in a multi-component carrier system in which the terminal operates a plurality of serving cells, the PDCCH can be transmitted in each serving cell. For example, in any subframe k, when PDCCH1 is transmitted on the first serving cell, PDCCH2 is transmitted on the second serving cell, and no PDCCH is transmitted on the third serving cell, subframe k is the first. The PDCCH subframe is correct for the serving cell and the second serving cell, but is not the PDCCH subframe for the third serving cell. That is, even the same subframe may be a PDCCH subframe for each serving cell or may not be a PDCCH subframe.

This is the same even when the TDD uplink / downlink configuration is different for each serving cell in the TDD system. For example, in the case of FIG. 4, subframe 4 is an uplink subframe for the primary serving cell and the first secondary serving cell, and a downlink subframe for the second secondary serving cell and the third secondary serving cell. Accordingly, subframe 4 is not a PDCCH subframe for the primary serving cell and the first secondary serving cell, but a PDCCH subframe for the second secondary serving cell and the third secondary serving cell.

If, in this multi-component carrier system, one subframe is defined as a PDCCH subframe or a non-PDCCH subframe, ignoring the specificity of each serving cell as in a single carrier system, the UE is in an uplink subframe in which the PDCCH is not transmitted. There is a strange problem of monitoring the PDCCH. This does not comply with the rule that TDD uplink / downlink configuration is individually determined for each serving cell in interband aggregation. Therefore, from the viewpoint of a multi-component carrier system, PDCCH subframes are determined individually for each serving cell, and even in a TDD system, PDCCH subframes are individually determined for each serving cell. The UE may monitor the PDCCH in a PDCCH subframe in at least one serving cell regardless of all-duplex or semi-duplex.

Here, although the downlink subframe is assumed to be a PDCCH subframe, this is only an example. Even in the case of a half-duplex UE, the downlink subframe may not be the PDCCH subframe depending on the situation. For example, if it is promised to prioritize the uplink subframe of the primary serving cell and ignore the downlink subframe of another secondary serving cell in case of subframe conflict, the downlink subframe of the secondary serving cell is not a PDCCH subframe. . Or, for example, the downlink subframe that does not include the PDCCH according to the PDCCH or SPS resource allocation criteria is not a PDCCH subframe. On the other hand, in the case of an all-duplex terminal, the downlink subframe is a PDCCH subframe.

In addition, in the case of an inactive serving cell, all subframes of the serving cell may not be a PDCCH subframe. This is because the UE is scrambled with a PDCCH that includes downlink and uplink resource allocation control information for the deactivated serving cell, that is, C-RNTI, and is configured for the deactivated serving cell (UE-specific search space). ) Can not be monitored.

Hereinafter, the operation of the duration timer, the DRX inactivity timer, and the DRX retransmission timer in the multi-component carrier system will be started based on the PDCCH subframe defined from the perspective of the multi-component carrier system.

1.on duration timer

The duration timer is started by the start of the DRX cycle. In other words, the start of the duration timer coincides with the start of the DRX cycle. The value of the duration timer is increased by one when the predetermined condition is satisfied, and expires when the duration timer value is equal to the first preset expiration value. The duration timer is valid until the duration timer value is equal to the first expiration value.

At this time, it may be a problem in which condition the duration timer value increases. For example, since the duration timer specifies the number of consecutive PDCCH subframes under a single carrier system, the duration timer value is increased by 1 for every PDCCH subframe. However, under the multi-component carrier system, since the PDCCH subframes can be individually configured for each serving cell, it is necessary to determine under what conditions the duration timer value is increased. Different conditions under which the duration timer value increases may mean that the definition of the duration timer is different. The different definition of the duration timer may also mean that the operation method of the duration timer is different. Hereinafter, various embodiments of an operation method of a duration timer will be described in detail with reference to the accompanying drawings.

(1) As an example, in the multi-component carrier system, the duration timer value may be increased by 1 when the PDCCH subframe is configured in at least one serving cell based on the current subframe. That is, if there is no PDCCH subframe across all serving cells based on the current subframe, the duration timer value maintains the value in the previous subframe. In this sense, the duration timer specifies the number of consecutive or cumulative PDCCH subframes for at least one activated serving cell among the serving cells configured in the terminal from the start of the DRX cycle. . Here, the at least one serving cell is configured in the terminal and is assumed to be an activated serving cell. A detailed operation method will be described with reference to FIG. 6.

6 is an exemplary diagram in which a duration timer according to an embodiment of the present invention operates.

Referring to FIG. 6, a main serving cell (PCell) and a secondary serving cell (SCell) are configured in a terminal. The main serving cell and the secondary serving cell are both active serving cells. As a TDD-based system, different TDD uplink / downlink configurations are allocated to a primary serving cell and a secondary serving cell. For example, as shown in FIG. 6, TDD uplink / downlink configuration 0 (conf 0) is allocated to the primary serving cell, and TDD uplink / downlink configuration 3 (conf 3) is allocated to the secondary serving cell. The TDD uplink / downlink configuration of the primary serving cell is performed from subframe 0 to subframe 5 in the next radio frame. D-> S-> U-> U-> U-> ...-> U-> It is formed as D. The TDD uplink / downlink configuration of the secondary serving cell is performed from D-> S-> U-> U-> U-> D-> D-> D- from subframe 0 to subframe 5 in the next radio frame. > D-> D-> ...-> U-> D. Here, the downlink subframe or the special subframe is regarded as a PDCCH subframe.

Assume that the period of the DRX cycle is 8 ms and the first expiration value for the duration timer is set to psf3. When the DRX cycle begins in subframe 0, the duration timer also starts. As the duration timer starts, the UE enters the active time, and the UE may monitor the PDCCH for the PDCCH subframe during the active time. Based on subframe 0, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Thus, the duration timer has a value of 1.

Based on subframe # 1, the main serving cell and the secondary serving cell are special subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Therefore, the value of the duration timer is increased by one to two. Based on subframes 2, 3, and 4, both the primary serving cell and the secondary serving cell are uplink subframes, not all PDCCH subframes. This does not satisfy the condition that the PDCCH subframe is configured in at least one serving cell. Thus, the value of the duration timer remains at two. Of course, the activity time continues.

Based on subframe # 5, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Therefore, the value of the duration timer is increased by one to three. If the value of the duration timer is 3, which is equal to the first expiration value psf3, the duration timer expires and the activity time ends. However, since the DRX cycle period has not yet ended, the UE enters inactivity time in the remaining subframes 6 and 7. Meanwhile, since the DRX cycle 8ms period ends in subframe # 7, the first DRX cycle ends.

In subframe 8, the second DRX cycle begins, with a duration timer likewise. In this case, the first expiration value is psf3. The activity time is also started as the start of the duration timer, and during the activity time, the UE performs PDCCH monitoring in every PDCCH subframe.

Based on subframe # 8, an uplink subframe is configured in the primary serving cell, and a downlink subframe is configured in the secondary serving cell. Although there is no PDCCH subframe in the primary serving cell, since there is a PDCCH subframe in the secondary serving cell, the condition that the PDCCH subframe is configured in at least one serving cell is satisfied. Thus, the duration timer has a value of 1.

Based on subframe 9, an uplink subframe is configured in the main serving cell, and a downlink subframe is configured in the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell as in subframe # 8. Thus, the duration timer has a value of 2.

Based on subframe 0 in the next radio frame, a downlink subframe is configured in both the primary serving cell and the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Thus, the duration timer has a value of 3.

If the value of the duration timer is 3, which is equal to the first expiration value psf3, the duration timer expires and the activity time ends. However, since the DRX cycle period has not yet finished, the UE enters inactivity time in subframes 1, 2, 3, 4, and 5.

(2) As another example, in the multi-component carrier system, the duration timer may be increased by 1 when PDCCH subframes are configured in all serving cells configured in the terminal based on the current subframe. Conversely, if only one is not a PDCCH subframe across all serving cells in the current subframe, the duration timer maintains the value in the immediately preceding subframe. In this sense, the duration timer specifies the number of consecutive or PDCCH subframes for all activated serving cells configured in the terminal from the start of the DRX cycle. A detailed operation method will be described with reference to FIG. 7.

7 is an exemplary diagram in which a duration timer according to another embodiment of the present invention operates.

Referring to FIG. 7, a main serving cell (PCell) and a secondary serving cell (SCell) are configured in a terminal. The main serving cell and the secondary serving cell are both active serving cells. As a TDD-based system, TDD uplink / downlink configuration 0 (conf 0) is allocated to the primary serving cell and TDD uplink / downlink configuration 3 (conf 3) is allocated to the secondary serving cell.

Assume that the period of the DRX cycle is 8 ms and the first expiration value for the duration timer is set to psf3. When the DRX cycle begins in subframe 0, the duration timer also starts. As the duration timer starts, the UE enters the active time, and the UE may monitor the PDCCH for the PDCCH subframe during the active time.

First, based on subframe 0, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in all configured serving cells. Thus, the duration timer has a value of 1.

Based on subframe # 1, the main serving cell and the secondary serving cell are special subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in all configured serving cells. Therefore, the value of the duration timer is increased by one to two. Based on subframes 2, 3, and 4, both the primary serving cell and the secondary serving cell are uplink subframes, not all PDCCH subframes. This does not satisfy the condition that the PDCCH subframe is configured in all configured serving cells. Thus, the value of the duration timer remains at two. Of course, the activity time continues.

Based on subframe # 5, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in all configured serving cells. Therefore, the value of the duration timer is increased by one to three. If the value of the duration timer is 3, which is equal to the first expiration value psf3, the duration timer expires and the activity time ends. However, since the DRX cycle period has not yet ended, the UE enters inactivity time in the remaining subframes 6 and 7. Meanwhile, since the DRX cycle 8ms period ends in subframe # 7, the first DRX cycle ends.

In subframe 8, the second DRX cycle begins, with a duration timer likewise. In this case, the first expiration value is psf3. The activity time is also started as the start of the duration timer, and during the activity time, the UE performs PDCCH monitoring in every PDCCH subframe.

Based on subframe # 8, an uplink subframe is configured in the primary serving cell, and a downlink subframe is configured in the secondary serving cell. Although there exists a PDCCH subframe in the secondary serving cell, since there is no PDCCH subframe in the secondary serving cell, the condition in which the PDCCH subframe is configured in all configured serving cells is not satisfied. Therefore, the duration timer has a value of zero. Not being configured in the PDCCH subframe in all serving cells does not necessarily mean that the UE does not monitor PDCCH. That is, the increase of the value of the duration timer and the monitoring of the PDCCH may be performed in separate operations. For example, if a PDCCH subframe exists even in one serving cell, the UE may monitor the corresponding PDCCH subframe even if the value of the duration timer does not change. This is because it corresponds to the activity time. Or, even if there is a PDCCH subframe in one serving cell, when the PDCCH subframe is not configured for all serving cells, the UE may not perform PDCCH monitoring. This depends on the performance of the terminal. For example, this is because a half-duplex terminal does not support uplink transmission and downlink reception at the same time.

Subframe # 9, like # 8, has a PDCCH subframe in the secondary serving cell, but there is no PDCCH subframe in the secondary serving cell, and thus does not satisfy the condition that the PDCCH subframe is configured in all configured serving cells. Therefore, the value of the duration timer remains at zero.

Based on subframe 0 in the next radio frame, a downlink subframe is configured in both the primary serving cell and the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in all configured serving cells. Thus, the duration timer has a value of 1.

Based on subframe 1, a special subframe is configured in both the main serving cell and the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in all configured serving cells. Thus, the duration timer has a value of 2.

Based on subframes 2, 3, and 4, both the primary serving cell and the secondary serving cell are uplink subframes, not all PDCCH subframes. This does not satisfy the condition that the PDCCH subframe is configured in all configured serving cells. Thus, the value of the duration timer remains at two. Of course, the activity time continues.

Based on subframe number 5, a downlink subframe is configured in both the main serving cell and the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in all configured serving cells. Thus, the duration timer has a value of 3.

If the value of the duration timer is 3, which is equal to the first expiration value psf3, the duration timer expires and the activity time ends.

Comparing the embodiment of FIG. 6 and FIG. 7, it can be seen that the period of activity time is different within the DRX cycle. In the second DRX cycle, the active time occupies the entire DRX cycle in FIG. 7, but in the case of FIG. 6, the active time is shorter as three subframes. Depending on how the standard is defined in the serving cell, the activity time may be longer or shorter. By defining a PDCCH subframe at each serving cell level and determining whether the duration timer value is increased based on the PDCCH subframe defined at each serving cell level, an operation method of the DRX timer can be clarified.

(3) As another example, in the multi-component carrier system, the duration timer may increase by 1 when the PDCCH subframe is configured in the main serving cell configured in the terminal based on the current subframe. In other words, even if a PDCCH subframe is configured in another secondary serving cell in the current subframe, when the PDCCH subframe is not configured in the main serving cell, the duration timer maintains the value in the previous subframe. In this sense, the duration timer specifies the number of consecutive or PDCCH subframes for the main serving cell configured in the terminal from the start of the DRX cycle. A detailed operation method will be described with reference to FIG. 8.

8 is an exemplary diagram in which a duration timer according to another embodiment of the present invention operates.

Referring to FIG. 8, a main serving cell (PCell) and a secondary serving cell (SCell) are configured in a terminal. The main serving cell and the secondary serving cell are both active serving cells. As a TDD type system, TDD uplink / downlink configuration No. 2 (conf 2) is allocated to the primary serving cell, and TDD uplink / downlink configuration number 0 (conf 0) is allocated to the secondary serving cell.

Assume that the period of the DRX cycle is 8 ms and the first expiration value for the duration timer is set to psf3. When the DRX cycle begins in subframe 0, the duration timer also starts. As the duration timer starts, the UE enters the active time, and the UE may monitor the PDCCH for the PDCCH subframe during the active time.

First, based on subframe 0, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that the PDCCH subframe is configured in the main serving cell. Thus, the duration timer has a value of 1.

Based on subframe # 1, the main serving cell and the secondary serving cell are special subframes, and both are PDCCH subframes. This satisfies the condition that the PDCCH subframe is configured in the configured main serving cell. Therefore, the value of the duration timer is increased by one to two.

Based on subframe # 2, both the primary serving cell and the secondary serving cell are uplink subframes, and not all of the PDCCH subframes. This does not satisfy the condition that the PDCCH subframe is configured in the configured main serving cell. Thus, the value of the duration timer remains at two. Of course, the activity time continues.

Based on subframe # 3, the primary serving cell is a downlink subframe and the secondary serving cell is an uplink subframe. That is, the PDCCH subframe is configured only in the main serving cell. This satisfies the condition that the PDCCH subframe is configured in the configured main serving cell. Therefore, the value of the duration timer is increased by one to three. If the value of the duration timer is 3, which is equal to the first expiration value psf3, the duration timer expires and the activity time ends. However, since the DRX cycle period has not yet finished, the UE enters inactivity time in the remaining subframes 4, 5, 6, and 7. Meanwhile, since the DRX cycle 8ms period ends in subframe # 7, the first DRX cycle ends.

In subframe 8, the second DRX cycle begins, with a duration timer likewise. In this case, the first expiration value is psf3. The activity time is also started as the start of the duration timer, and during the activity time, the UE performs PDCCH monitoring in every PDCCH subframe.

Based on subframe # 8, a downlink subframe is configured in the primary serving cell and an uplink subframe is configured in the secondary serving cell. This satisfies the condition that the PDCCH subframe of the main serving cell is configured. Thus, the duration timer has a value of 1.

Since this is the same condition in subframe 9 and subframe 0 of the next radio frame, the value of the duration timer is increased to 2 and 3, and the duration timer expires in subframe 0.

If the downlink subframe is configured in the secondary serving cell during the active time, the UE may monitor the PDCCH subframe of the secondary serving cell even if the uplink subframe is configured in the main serving cell.

2.DRX inactivity timer

The DRX inactivity timer may be defined as the number of consecutive PDCCH subframes from the point in time at which the PDCCH for uplink or downlink user data transmission is successfully decoded. It is time for the UE to continuously monitor the PDCCH since continuous data reception may occur. The DRX inactivity timer is started or restarted when the UE successfully decodes the PDCCH for the HARQ initial transmission in the PDCCH subframe. In order to monitor the PDCCH, the UE must enter an active time during the DRX operation. Therefore, in order for the DRX inactivity timer to start, it is required that the UE enters the active time by the duration timer, etc., that there is a PDCCH subframe, and that the PDCCH decoding is successful.

The value of the DRX Inactivity Timer is incremented by one when a certain condition is satisfied, and expires when the DRX Inactivity Timer value is equal to a second preset expiration value. The DRX Inactivity Timer is valid until the DRX Inactivity Timer value is equal to the second expiration value.

In this case, it may be a problem in which condition the DRX inactivity timer value starts or increases. For example, under a single carrier system, since the DRX inactivity timer specifies the number of consecutive PDCCH subframes from the successful decoding of the PDCCH, the DRX inactivity timer value is increased by one for every PDCCH subframe.

However, under the multi-component carrier system, since each PDCCH subframe can be configured for each serving cell, it is necessary to determine under what conditions the DRX inactivity timer value is increased. Different conditions under which the DRX Inactivity Timer value increases may mean that the definition of the DRX Inactivity Timer is different. Different definitions of the DRX inactivity timer may also mean that the DRX inactivity timer operates differently.

In the multi-component carrier system, the DRX inactivity timer is a case in which a PDCCH subframe is configured in at least one serving cell based on the current subframe, and starts when the UE successfully decodes the PDCCH. In addition, in the multi-component carrier system, the DRX inactivity timer value is increased by 1 when the PDCCH subframe is configured in at least one serving cell based on the current subframe. In other words, if there is no PDCCH subframe across all serving cells based on the current subframe, the DRX inactivity timer value maintains the value in the previous subframe. The base station may transmit data through any serving cell of the terminal when there is data to transmit to the terminal, it is not necessary to limit that the PDCCH subframe is configured in all serving cells.

Here, the at least one serving cell is configured in the terminal and is assumed to be an activated serving cell. Hereinafter, an embodiment of an operation method of a DRX inactivity timer will be described in detail with reference to the accompanying drawings.

9 is an exemplary diagram in which a DRX inactivity timer operates according to an embodiment of the present invention.

Referring to FIG. 9, a main serving cell (PCell) and a secondary serving cell (SCell) are configured in a terminal. The main serving cell and the secondary serving cell are both active serving cells. As a TDD-based system, TDD uplink / downlink configuration 0 (conf 0) is allocated to the primary serving cell and TDD uplink / downlink configuration 3 (conf 3) is allocated to the secondary serving cell.

Assume that the period of the DRX cycle is 8 ms and the second expiration value for the DRX inactivity timer is set to psf3. When the DRX cycle starts in subframe 0, a duration timer starts with this, and the terminal enters the active time. The UE may monitor the PDCCH for the PDCCH subframe during the active time.

Based on subframe 0, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. In addition, since the UE successfully decodes the PDCCH of the primary serving cell, the DRX inactivity timer starts, and the value of the DRX inactivity timer is 1.

Based on subframe # 1, the main serving cell and the secondary serving cell are special subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Thus, the value of the DRX Inactivity Timer is increased by one to two. Based on subframes 2, 3, and 4, both the primary serving cell and the secondary serving cell are uplink subframes, not all PDCCH subframes. This does not satisfy the condition that the PDCCH subframe is configured in at least one serving cell. Thus, the value of the DRX Inactivity Timer remains at 2. Of course, the activity time continues.

Based on subframe # 5, the main serving cell and the secondary serving cell are downlink subframes, and both are PDCCH subframes. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Thus, the value of the DRX Inactivity Timer is increased by one to three. If the value of the DRX Inactivity Timer is 3, it is equal to the second expiration value psf3, so the DRX Inactivity Timer expires and the activity time ends. However, since the DRX cycle period has not yet ended, the UE enters inactivity time in the remaining subframes 6 and 7. Meanwhile, since the DRX cycle 8ms period ends in subframe # 7, the first DRX cycle ends.

In the subframe 8, the second DRX cycle starts. In this case, the duration timer starts, and the terminal enters the active time. Since the activity time, the UE can monitor the PDCCH. However, in subframe 8, since the UE does not successfully decode the PDCCH, the DRX inactivity timer does not start.

In subframe 9, the UE successfully decodes the PDCCH. Based on subframe 9, an uplink subframe is configured in the main serving cell, and a downlink subframe is configured in the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell as in subframe # 8. Therefore, the DRX Inactivity Timer starts, and the value of the DRX Inactivity Timer is 1.

Based on subframe 0 in the next radio frame, a downlink subframe is configured in both the primary serving cell and the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Therefore, the value of the DRX Inactivity Timer is 2.

Based on the next subframe 1, a special subframe is configured in both the main serving cell and the secondary serving cell. This satisfies the condition that a PDCCH subframe is configured in at least one serving cell. Therefore, the value of the DRX Inactivity Timer is 3.

If the value of the DRX Inactivity Timer is 3, it is equal to the second expiration value psf3, so the DRX Inactivity Timer expires and the activity time ends. However, since the DRX cycle period has not yet finished, the UE enters inactivity time in subframes 1, 2, 3, 4, and 5.

3.DRX retransmission timer

The DRX retransmission timer is a timer that operates based on the maximum value of consecutive numbers of PDCCH subframes for which downlink retransmission is expected by the terminal soon. The DRX retransmission timer is a timer that is started when the HARQ RTT timer has expired but fails to receive the retransmission data. The UE can monitor reception of data retransmitted in the HARQ process while the DRX retransmission timer is in progress. The setting of the DRX retransmission timer is defined by the MAC-MainConfig message of the RRC layer.

The value of the DRX retransmission timer is incremented by one when a certain condition is satisfied, and expires when the DRX retransmission timer value is equal to a third preset expiration value. Until the DRX retransmission timer value is equal to the third expiration value, the DRX retransmission timer is valid or stops in some cases.

Under the multi-component carrier system, since each PDCCH subframe can be configured for each serving cell, it is necessary to determine under what conditions the DRX retransmission timer value starts or increases. Different conditions under which the DRX retransmission timer value increases may mean that the definition of the DRX retransmission timer is different. The different definition of the DRX retransmission timer may also mean that the operation method of the DRX retransmission timer is different.

In the multi-component carrier system, the DRX retransmission timer starts when i) the HARQ RTT timer expires and ii) the PDCCH subframe is configured in the serving cell where the HARQ retransmission is in progress for the all-duplex UE. In addition, in the multi-component carrier system, the DRX retransmission timer value is increased by 1 when the PDCCH subframe is configured in the serving cell in which HARQ retransmission is in progress. In other words, if there is no PDCCH subframe in the serving cell in which HARQ retransmission is in progress, the DRX retransmission timer value maintains the value in the previous subframe. This is because HARQ retransmission occurs and operation is performed independently for each serving cell. Therefore, counting the timer based on the PDCCH subframe defined in the serving cell in which the HARQ retransmission is performed corresponds to the design intention of the DRX retransmission timer.

On the other hand, in the multi-component carrier system, the DRX retransmission timer is a semi-duplex UE, i) HARQ RTT timer expires, ii) PDCCH subframe is configured in the serving cell in which HARQ retransmission is in progress, iii) reference cell starts when an uplink subframe is not configured in a cell). After the DRX retransmission timer is started, the value of the DRX retransmission timer is increased by 1 if the conditions ii) and iii) are satisfied. According to this, eventually, based on the current subframe, it is required to configure the PDCCH subframe in all serving cells configured in the terminal.

Meanwhile, in the multi-component carrier system, the DRX retransmission timer is stopped when i) DRX retransmission timer is in progress, and ii) UE decodes PDCCH and PDSCH successfully in a serving cell in which HARQ retransmission occurs.

As such, the start condition of the DRX retransmission timer in the multi-component carrier system can be defined differently according to the performance of the terminal. Hereinafter, a case of an all-duplex terminal and a case of a half-duplex terminal will be described, and an operation method of a DRX retransmission timer according to each case will be described with reference to the drawings.

(1) DRX retransmission timer of all-duplex terminal

10 is an exemplary diagram in which a DRX retransmission timer operates according to an embodiment of the present invention.

Referring to FIG. 10, a main serving cell (PCell) and a secondary serving cell (SCell) are configured in a terminal. The main serving cell and the secondary serving cell are both active serving cells. As a TDD-based system, TDD uplink / downlink configuration 0 (conf 0) is allocated to the primary serving cell and TDD uplink / downlink configuration 3 (conf 3) is allocated to the secondary serving cell.

On the secondary serving cell of subframe 0, the UE receives the PDCCH and the PDSCH. The primary serving cell and the secondary serving cell are downlink subframes, but only the secondary serving cell related to the HARQ operation is regarded as a PDCCH subframe. Upon reception of the PDCCH and PDSCH, the HARQ RTT timer of the UE is started.

The HARQ RTT timer specifies the minimum number of subframes before the downlink retransmission expected by the UE. For example, for an FDD system, the HARQ RTT timer is set to 8 subframes. On the other hand, in the TDD system, the HARQ RTT timer is set to k + 4 subframes, where k is defined as the interval between the downlink transmission and the transmission of the HARQ feedback. HARQ RTT timer is defined for each downlink HARQ process. During the HARQ RTT timer, the UE determines that there is no retransmission of downlink data for the corresponding HARQ process. Therefore, the terminal does not proceed with the reception operation for the HARQ process. For example, if the UE does not receive any downlink data other than the HARQ process and the corresponding subframe is not included in the active time, the UE does not need to perform PDCCH monitoring.

If the PDSCH decoding fails in subframe 0, the UE transmits a NACK signal to the base station in subframe 4 after 4 subframes. Since the HARQ RTT timer expires in subframe 7 and the secondary serving cell of subframe 8 is a downlink subframe, it corresponds to a PDCCH subframe. This satisfies that i) the HARQ RTT timer expires and ii) the PDCCH subframe is configured in the secondary serving cell in which HARQ retransmission is in progress. Accordingly, the terminal starts the DRX retransmission timer, where the value of the DRX retransmission timer is 1.

Based on subframe 9, it is still satisfied that i) the HARQ RTT timer expires and ii) the PDCCH subframe is configured in the secondary serving cell in which HARQ retransmission is in progress. Thus, the value of the DRX retransmission timer increases to two.

Based on subframe 0 of the next radio frame, it is still satisfied that i) the HARQ RTT timer expires and ii) the PDCCH subframe is configured in the secondary serving cell in which HARQ retransmission is in progress. Thus, the value of the DRX retransmission timer increases to three.

Based on subframe 1, it is still satisfied that i) the HARQ RTT timer expires and ii) the PDCCH subframe is configured in the secondary serving cell in which HARQ retransmission is in progress. Therefore, the value of the DRX retransmission timer increases to four. At this point, the DRX retransmission timer may expire. At the same time, the UE may receive the PDCCH and PDSCH, and may stop the DRX retransmission timer upon successful decoding.

(2) DRX retransmission timer of semi-duplex terminal

11 is an exemplary diagram in which a DRX retransmission timer operates according to another example of the present invention.

Referring to FIG. 11, a main serving cell (PCell) and a secondary serving cell (SCell) are configured in a terminal. The main serving cell and the secondary serving cell are both active serving cells. As a TDD-based system, TDD uplink / downlink configuration 0 (conf 0) is allocated to the primary serving cell and TDD uplink / downlink configuration 3 (conf 3) is allocated to the secondary serving cell.

On the secondary serving cell of subframe 0, the UE receives the PDCCH and the PDSCH. The primary serving cell and the secondary serving cell are downlink subframes, but only the secondary serving cell related to the HARQ operation is regarded as a PDCCH subframe. Upon reception of the PDCCH and PDSCH, the HARQ RTT timer of the UE is started.

If the PDSCH decoding fails in subframe 0, the UE transmits a NACK signal to the base station in subframe 4 after 4 subframes. The HARQ RTT timer expires in subframe seven. In this case, when the condition for starting the DRX retransmission timer is determined, an uplink subframe is configured in the main serving cell and a downlink subframe is configured in the secondary serving cell in subframe # 8. That is, subframe 8 is a conflicting subframe. When the reference cell is the primary serving cell, i) the HARQ RTT timer expires, and ii) the PDCCH subframe is configured in the secondary serving cell in which HARQ retransmission is in progress, but iii) the uplink subframe is configured in the reference cell. It does not satisfy the condition that it is not. Therefore, the downlink subframe of the secondary serving cell is not regarded as a PDCCH subframe, and the DRX retransmission timer is not started. Subframes 7 and 9 are the same as subframe 8.

Meanwhile, in subframe 0 of the next radio frame, a downlink subframe is configured in both the main serving cell and the secondary serving cell. Accordingly, i) the HARQ RTT timer expires, ii) the PDCCH subframe is configured in the secondary serving cell in which HARQ retransmission is in progress, and iii) the UL subframe is not configured in the reference cell. Thus, the DRX Retransmission Timer is started, and the value of the DRX Retransmission Timer is 1. At this time, the activity time starts, the terminal performs the PDCCH monitoring.

Based on subframe 1, since the conditions i), ii), and iii) are still satisfied, the value of the DRX retransmission timer increases to two. At this point, the DRX retransmission timer does not expire, but when the UE receives the PDCCH and PDSCH and successfully decodes, the DRX retransmission timer may be stopped. This ends the activity time.

As another example, the start of the DRX retransmission timer may be performed only if i) the HARQ RTT timer expires and iv) the decoding of data in the buffer of the HARQ process in which the HARQ RTT timer is driven fails. The counting of the DRX retransmission timer operates only when all the conditions i), ii) and iii) are satisfied. Therefore, since the DRX retransmission timer can be started even if it is not a PDCCH subframe, the activity time can always be started from the subframe where the HARQ RTT timer expires.

12 is a signaling flowchart between a terminal and a base station for a DRX operation according to an embodiment of the present invention.

Referring to FIG. 12, the base station transmits DRX configuration information to the terminal (S1100). The DRX configuration information is a set of parameters required for the DRX operation and specifies a value of a duration timer, a value of a DRX inactivity timer, and a value of a DRX retransmission timer. Meanwhile, the DRX configuration information may be received in a MAC-MainConfig message, which is an RRC message used to specify a main configuration of a MAC layer for a signaling radio bearer (SRB) and a data radio bearer (DRB). The DRX configuration information can be configured, for example, as shown in the following table.

DRX-Config :: = CHOICE { release NULL, setup SEQUENCE { onDurationTimer ENUMERATED { psf1, psf2, psf3, psf4, psf5, psf6, psf8, psf10, psf20, psf30, psf40, psf50, psf60, psf80, psf100, psf200}, drx-InactivityTimer ENUMERATED { psf1, psf2, psf3, psf4, psf5, psf6, psf8, psf10, psf20, psf30, psf40, psf50, psf60, psf80, psf100, psf200, psf300, psf500, psf750, psf1280, psf1920, psf2560, psf0-v1020, spare9, spare8, spare7, spare6, spare5, spare4, spare3, spare2, spare1}, drx-RetransmissionTimer ENUMERATED { psf1, psf2, psf4, psf6, psf8, psf16, psf24, psf33}, } OPTIONAL-Need OR }

Referring to Table 2, the DRX configuration information includes an onDurationTimer field defining a value of a duration timer, a drx-InactivityTimer field indicating a value of a DRX inactivity timer, and a drx-RetransmissionTimer field indicating a value of a DRX retransmission timer. do. The onDurationTimer field may be set to any one of {psf1, psf2, psf3, ... psf200}. psf means a PDCCH subframe, and the number after psf indicates the number of PDCCH subframes. That is, psf represents the expiration value of the timer as the number of PDCCH subframes. For example, if the onDurationTimer field = psf1, the duration timer expires after progressing cumulatively to one PDCCH subframe including the subframe where the DRX cycle started. Or the onDurationTimer field = psf4, the duration timer expires after progressing from the beginning of the DRX cycle cumulatively to the four PDCCH subframes.

The drx-InactivityTimer field may be set to any one of {psf1, psf2, psf3, ... psf2560}. For example, if the drx-InactivityTimer field = psf3, the DRX inactivity timer expires after progressing up to three PDCCH subframes cumulatively, including the subframe at the time of driving. The drx-RetransmissionTimer field may be set to any one of {psf1, psf2, psf4, ... psf33}. For example, if the drx-RetransmissionTimer field = psf4, the DRX retransmission timer expires after progressing up to four PDCCH subframes including the subframe at the time when it is driven.

The terminal sets a DRX related timer based on the DRX configuration information (S1205). DRX related timers include a duration timer, a DRX inactivity timer, and a DRX retransmission timer. For example, the terminal may set the first expiration value of the duration timer to psf3, set the second expiration value of the DRX inactivity timer to psf2, and set the third expiration value of the DRX retransmission timer to psf4.

As described in FIGS. 6 to 11, the UE proceeds with an active time in a DRX cycle based on a start condition of each timer, an increase condition of a timer value, a stop condition, and an expire condition, and monitors the PDCCH during the active time ( S1210).

During the active time, the base station transmits a PDCCH subframe necessary for the terminal (S1215). The PDCCH subframe is configured on an active serving cell and can be handled individually for each serving cell.

13 is a flowchart illustrating a DRX operation by a terminal according to an embodiment of the present invention.

Referring to Figure 13, the terminal receives the DRX configuration information from the base station (S1300).

The terminal sets a DRX parameter based on the DRX configuration information and drives a DRX related timer (S1305). Here, the DRX related timer includes a duration timer and a DRX inactivity timer. In step S1305, it is assumed that the start conditions of the duration timer and the DRX inactivity timer are satisfied. When the duration timer and the DRX inactivity timer are driven, it means that the UE enters the active time in the DRX cycle.

Therefore, the UE monitors the PDCCH (S1310). Monitoring of the PDCCH is performed when there is a PDCCH subframe.

The UE checks whether the PDCCH subframe is configured in the serving cell determining the increase of the timer value (S1315). As an example, when a timer value is increased by configuring a PDCCH subframe in all serving cells configured in the terminal, the serving cell determining the increase in the timer value is all the serving cells configured in the terminal. Accordingly, the UE checks whether PDCCH subframes are configured in all serving cells configured in the UE. As another example, when the timer value is increased by configuring a PDCCH subframe in at least one serving cell configured in the terminal, the serving cell determining the increase in the timer value is at least one serving cell configured in the terminal. Accordingly, the UE checks whether a PDCCH subframe is configured in at least one serving cell configured in the UE. As another example, when the timer value is increased by configuring a PDCCH subframe in the main serving cell, the serving cell determining the increase in the timer value is the primary serving cell. Accordingly, the UE checks whether a PDCCH subframe is configured in the main serving cell.

In step S1315, if the UE determines that the PDCCH subframe is configured in the serving cell that determines the increase in the timer value, the UE increases the timer value by one (S1320).

In operation S1325, the UE checks whether a timer value in the current subframe is equal to an expiration value preset for the timer. If the timer value is equal to the expiration value, the terminal expires the timer (S1330).

In step S1315, if the UE determines that the PDCCH subframe is not configured in the serving cell determining the increase of the timer value, the UE maintains the timer value and receives the next PDCCH subframe (S1335).

14 is a flowchart illustrating a DRX operation by a terminal according to another example of the present invention.

Referring to Figure 14, the terminal receives the DRX configuration information from the base station (S1400).

The terminal sets a DRX parameter based on the DRX configuration information and drives a DRX retransmission timer (S1405). In step S1405, it is assumed that the start condition of the DRX retransmission timer is satisfied. The operation of the DRX retransmission timer means that the UE has entered an active time in the DRX cycle.

Therefore, the UE monitors the PDCCH in the PDCCH subframe (S1410). Monitoring of the PDCCH is performed when there is a PDCCH subframe.

The UE checks whether a PDCCH subframe is configured in the serving cell in which HARQ retransmission or operation is performed (S1415). Here, the PDCCH subframe is defined differently according to the performance of the UE. For example, in the case of an all-duplex UE, the PDCCH subframe is defined based on FIG. 10, and in the case of the semi-duplex UE, the PDCCH subframe is based on FIG. 11, when it is not a conflicting subframe with the main serving cell. Only a PDCCH subframe is considered.

In step S1415, if the UE determines that the PDCCH subframe is configured in the serving cell for HARQ retransmission or operation, the UE increases the DRX retransmission timer value by 1 (S1420).

The terminal checks whether reception of HARQ retransmission is successful (S1425). If the terminal successfully decodes HARQ downlink data (including PDCCH and PDSCH) retransmitted from the base station, the terminal stops the DRX retransmission timer (S1430). If the terminal does not successfully decode HARQ downlink data (including PDCCH and PDSCH) retransmitted from the base station, the terminal checks whether the DRX retransmission timer value is equal to the third expiration value (S1440).

In step S1440, if the DRX retransmission timer value is equal to the third expiration value, the terminal expires the DRX retransmission timer (S1445). This ends the activity time. On the other hand, if the DRX retransmission timer value is not equal to the third expiration value, the UE receives the next PDCCH subframe (S1435).

In step S1415, if the UE determines that the PDCCH subframe is not configured in the serving cell undergoing HARQ retransmission or operation, or that the subframe conflict of the reference cell occurs even if configured, the UE determines the DRX retransmission timer value. It maintains and receives the next PDCCH subframe (S1435).

15 is a flowchart illustrating a DRX operation by a base station according to an embodiment of the present invention.

Referring to FIG. 15, the base station transmits secondary serving cell configuration information (S1500). The secondary serving cell configuration information is information used to configure two or more serving cells in a terminal supporting a multi-element carrier system, and may be included in an RRC connection reconfiguration message and transmitted to the terminal.

The base station transmits the DRX configuration information to the terminal (S1505). The DRX configuration information is a set of parameters related to the DRX operation, for example, as described in Table 2 above.

The base station transmits the PDCCH and the PDSCH to the terminal on the PDCCH subframe of at least one serving cell configured and activated in the terminal (S1510).

16 is a block diagram of a terminal and a base station performing a DRX operation according to an embodiment of the present invention.

Referring to FIG. 16, the terminal 1600 includes a receiver 1605, a terminal processor 1610, and a transmitter 1620. The terminal processor 1610 may further include a DRX operation controller 1611 and a data generator 1612.

The receiver 1605 receives the DRX configuration information, the PDCCH, and the PDSCH from the base station. The PDCCH or PDSCH may be received on any of the plurality of serving cells configured in the terminal 1600.

The DRX operation controller 1611 sets a DRX related timer based on the DRX configuration information. DRX related timers include a duration timer, a DRX inactivity timer, and a DRX retransmission timer. For example, the DRX operation controller 1611 sets the first expiration value of the duration timer to psf3, sets the second expiration value of the DRX inactivity timer to psf2, and sets the third expiration value of the DRX retransmission timer to psf4. Can be set. The DRX operation control unit 1611 starts each timer or changes the value of each timer based on the start condition and the increase condition, the stop condition, and the expiration condition of each timer as described with reference to FIGS. 6 to 11. Or stop each timer, expire each timer, manage the activity time within the DRX cycle, and monitor the PDCCH during the activity time.

If the timer is a duration timer or a DRX inactivity timer, the DRX operation controller 1611 checks whether a PDCCH subframe is configured in the serving cell required to increase the timer value. As an example, when the timer value is increased when the PDCCH subframe is configured in all the serving cells configured in the terminal 1600, the DRX operation controller 1611 configures the PDCCH subframe in all the serving cells configured in the terminal 1600. Check if it is. As another example, when the PDCCH subframe is configured in at least one serving cell configured in the terminal 1600, the timer value increases, the DRX operation controller 1611 may perform the PDCCH subframe in at least one serving cell configured in the terminal 1600. Check that the frame is configured. As another example, when the timer value is increased when the PDCCH subframe is configured in the main serving cell, the DRX operation controller 1611 checks whether the PDCCH subframe is configured in the main serving cell. If the DRX operation control unit 1611 confirms that the PDCCH subframe is configured in the serving cell required to increase the timer value, the DRX operation control unit 1611 increases the timer value by one. The DRX operation controller 1611 checks whether a timer value in the current subframe is equal to an expiration value preset for the timer. If the timer value is the same as the expiration value, the DRX operation controller 1611 expires the timer.

Next, when the timer is a DRX retransmission timer, the DRX operation control unit 1611 checks whether a PDCCH subframe is configured in the serving cell undergoing HARQ retransmission or operation. Here, the PDCCH subframe is defined differently according to the performance of the terminal 1600. For example, in the case of an all-duplex UE, the PDCCH subframe is defined based on FIG. 10, and in the case of the semi-duplex UE, the PDCCH subframe is based on FIG. 11 but is not a conflicting subframe with the main serving cell. Only a PDCCH subframe is considered.

If the DRX operation control unit 1611 confirms that the PDCCH subframe is configured in the serving cell in which HARQ retransmission or operation is performed, the DRX operation control unit 1611 increases the timer value by one.

The HARQ operation control unit 1612 checks whether reception of HARQ retransmission is successful. If the HARQ operation control unit 1612 confirms that the reception unit 1605 successfully decodes HARQ downlink data (including PDCCH and PDSCH) retransmitted from the base station 1650, the DRX operation control unit 1611 stops the timer. Let's do it. If the HARQ operation control unit 1612 confirms that the reception unit 1605 did not successfully decode HARQ downlink data (including PDCCH and PDSCH) retransmitted from the base station 1650, the DRX operation control unit 1611 determines the timer value. Check if this is equal to the third expiration value.

If the timer value is equal to the third expiration value, the DRX operation controller 1611 expires the timer. This ends the activity time. On the other hand, if the timer value is not equal to the third expiration value, the receiver 1605 receives the next PDCCH subframe.

If the DRX operation control unit 1611 determines that the PDCCH subframe is not configured in the serving cell undergoing HARQ retransmission or operation, or that a subframe conflict of the reference cell occurs even if configured, the DRX operation control unit 1611 determines Maintaining the DRX retransmission timer value, the receiver 1605 receives the next PDCCH subframe.

The transmitter 1620 transmits an ACK / NACK signal generated by the HARQ operation controller 1612 to the base station 1650.

The base station 1650 includes a transmitter 1655, a receiver 1660, and a base station processor 1670. The base station processor 1670 includes a control information generation unit 1671 and a HARQ operation control unit 1672.

The transmitter 1655 transmits the DRX configuration information, the PDCCH, and the PDSCH to the terminal 1600.

The receiver 1660 receives an ACK / NACK signal from the terminal 1600.

The control information generation unit 1671 generates DRX configuration information as shown in Table 2 and sends it to the transmission unit 1655, for example. The control information generation unit 1671 also generates downlink control information mapped to the PDCCH.

When the reception unit 1660 receives the NACK signal from the terminal 1600 in response to the downlink data transmitted from the transmission unit 1655 to the terminal 1600, the HARQ operation control unit 1672 manages the corresponding HARQ process number. The HARQ retransmission data is controlled so that the HARQ operation is retransmitted to the terminal 1600 within the maximum number of retransmissions.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (15)

In the discontinuous reception (DRX) method by the terminal in a time division duplex (TDD) based multi-component carrier system,
Receiving from the base station DRX configuration information including parameters relating to the DRX operation;
Starting the timer when a start condition of the timer is satisfied;
Monitoring a physical downlink control channel transmitted from the base station during an active time in which the timer is ongoing; And
Increasing the value of the timer by 1 when a PDCCH subframe including the physical downlink control channel is configured in a serving cell for determining an increase in the value of the timer; , Discontinuous reception method. The method of claim 1,
When the PDCCH subframe is not configured in the serving cell, the value of the timer is not changed. The method of claim 1,
And the timer comprises a duration timer for which the start condition is satisfied when a DRX cycle relating to the DRX operation starts. The method of claim 3, wherein
The serving cell determining the increase of the value of the timer is all of the serving cells configured in the terminal, at least one serving cell, or a primary serving cell (primary SCell), characterized in that the discontinuous reception method. The method of claim 1,
And the timer comprises a DRX inactive timer in which the start condition is satisfied when the physical downlink control channel is successfully decoded by the terminal. The method of claim 5, wherein
The serving cell determining the increase of the timer value is at least one serving cell among the serving cells configured in the terminal, discontinuous reception method. The method of claim 1,
The timer is a DRX retransmission timer that satisfies the start condition when the retransmission of the physical downlink shared channel indicated by the physical downlink control channel is not received until the expiration of a HARQ RTT (round trip time) timer. Discontinuous reception method, characterized in that it comprises a. The method of claim 7, wherein
And a serving cell for determining an increase in the value of the timer is a serving cell in which retransmission of the physical downlink shared channel is performed. A terminal performing a DRX operation in a multi-component carrier system based on time division duplex,
A receiver which receives from the base station DRX configuration information including a parameter related to a DRX operation; And
And a DRX operation control unit for starting the timer when the start condition of the timer is satisfied, and monitoring a physical downlink control channel transmitted from the base station during the active time period of the timer,
The DRX operation controller increases the value of the timer by 1 when a PDCCH subframe including the physical downlink control channel is configured in a serving cell that determines the increase of the value of the timer. Terminals, characterized in that does not change the value of the timer. The method of claim 9,
The DRX operation control unit, characterized in that the start condition is satisfied when the DRX cycle for the DRX operation starts, the terminal. 11. The method of claim 10,
The DRX operation controller may treat any one of all the serving cells, at least one serving cell, and the primary serving cell configured in the terminal as a serving cell for determining an increase in the value of the timer. Terminal. The method of claim 9,
The DRX operation controller is characterized in that the start condition is satisfied when the physical downlink control channel is successfully decoded by the terminal. 13. The method of claim 12,
The DRX operation control unit, characterized in that to treat at least one serving cell of the serving cells configured in the terminal as a serving cell for determining the increase of the value of the timer. The method of claim 9,
The DRX operation control unit treats the start condition as being satisfied when the retransmission of the physical downlink shared channel indicated by the physical downlink control channel is not received until the expiration of an HARQ RTT timer. . 15. The method of claim 14,
The terminal, characterized in that the DRX operation controller treats a serving cell in which retransmission of the physical downlink shared channel is performed as a serving cell for determining an increase in the value of the timer.

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