WO2018174635A1 - Method and wireless device for receiving paging message - Google Patents

Abstract

One disclosure in the present specification presents a method for a wireless device to receive a paging message. The method may comprise: a step of deciding a wake up signal occasion (WUSO) window for attempting to receive a wake up signal (WUS); and a step of monitoring a downlink control channel during a paging window so as to attempt to receive a paging message, if the WUS is received within the decided WUSO window. Here, the WUSO window may be decided according to a duration size and offset.

Description

How to Receive Paging Messages and Wireless Devices

The present invention relates to mobile communications.

When there is downlink data to be transmitted to a terminal in which the base station is in a radio resource control (RRC) idle state, the base station transmits a paging message to switch the terminal to the RRC connected mode.

In order for the terminal to receive a paging message, it is necessary to monitor a downlink control channel, for example, a physical downlink control channel (PDCCH). However, when the monitoring period is short, the period in which the terminal performs blind decoding (BD) is shortened, resulting in an increase in power consumption.

On the other hand, recently, considering the expansion or increase of the cell coverage of the base station for the Internet of Things (IoT) communication, various techniques for expanding or increasing the cell coverage has been discussed. In order to expand or increase the cell coverage, a downlink channel or an uplink channel may be repeatedly transmitted on several subframes.

However, when the repetitive transmission is performed, there is a problem in that power consumption of the terminal is increased.

Therefore, the present disclosure aims to solve the above-mentioned problem.

 In order to achieve the above object, one disclosure of the present specification provides a method for a wireless device to receive a paging message. The method includes determining a wake up signal occasion (WUSO) window to attempt to receive a wake up signal (WUS); Monitoring the downlink control channel during the paging window to attempt to receive the paging message when the WUS is received within the determined WUSO window. Here, the WUSO window may be determined by the size and offset of the interval.

A plurality of paging windows and / or paging occasions (POs) may be indicated by the WUS. The PO may indicate a subframe in which transmission of the paging message starts in the paging window.

The time interval in which the WUS exists in the determined WUSO window may be defined as WUSO.

The offset may indicate a difference from the PO to a start point or end point of the WUSO window.

If the subframe in which the WUSO exists is an invalid subframe, the WUSO may be postpone to a subsequent valid subframe.

The frequency resource region in which the WUSO window exists may be the same as the frequency resource region in which the PO exists.

Whether the WUSO is partially or fully overlapped on the search space and time resources of another downlink control channel or when the WUSO is partially or completely overlapped on another channel and the time resource, whether to transmit the WUS in the WUSO Regardless, the WUS's attempt to receive may be abandoned. As such, when the WUS reception attempt is abandoned, the reception of the paging message may be monitored during the PO corresponding to the WUSO.

The WUS may include an identifier of a wireless device or a group identifier of wireless devices that should receive the paging message.

The paging window may start after a certain gap from the start point of the WUSO window.

The block used by the WUS may be defined as a wake up signal block (WUSB). In this case, the repetition size of the WUSB may be determined based on an upper layer parameter set for the WUS and an upper layer parameter set for the paging message.

The WUS may be generated based on any one of a plurality of sequences. An identifier of a wireless device or a group identifier of wireless devices may be used to generate the sequence.

At least one of the plurality of sequences may be used to wake or sleep all wireless devices.

In order to achieve the above object, one disclosure of the present specification proposes a wireless device for receiving a paging message. The wireless device includes a transceiver; And it may include a processor for controlling the transceiver. The processor may determine a wake up signal occasion (WUSO) window to attempt to receive a wake up signal (WUS). When the WUS is received within the determined WUSO window, in order to attempt to receive the paging message, the processor may control the transceiver to monitor the downlink control channel during the paging window. The WUSO window may be determined by the size and offset of the interval.

According to the disclosure of the present specification, the above-described problems of the prior art are solved.

1 is a wireless communication system.

2 shows a structure of a radio frame according to FDD in 3GPP LTE.

3 shows a structure of a downlink subframe.

4 shows an example of a DRX cycle.

5A illustrates an example of Internet of Things (IoT) communication.

5B is an illustration of cell coverage extension or augmentation for IoT devices.

5C is an exemplary diagram illustrating an example of transmitting a bundle of downlink channels.

6A and 6B are exemplary views illustrating examples of subbands in which an IoT device operates.

7 shows an example of a time resource that can be used for NB-IoT in M-frame units.

8 is another exemplary diagram illustrating time resources and frequency resources that can be used for NB IoT.

9 is an exemplary view illustrating a paging procedure.

10A is a flowchart illustrating an example of utilizing WUS introduced according to the disclosure of the present specification, and FIG. 10B is an exemplary diagram illustrating WUS in the time domain.

11 is an exemplary view showing a WUSO window on a time axis.

12A is an exemplary diagram illustrating a first scheme of the second disclosure.

12B shows a variant of the first scheme of the second disclosure.

13 is an exemplary view illustrating a second scheme of the second disclosure.

14 is an exemplary view showing a first example of the third scheme of the second disclosure.

15 is an exemplary diagram illustrating a second example of the third scheme of the second disclosure.

16 is an exemplary view showing a third example of the third scheme of the second disclosure.

17 is an exemplary view showing a solution according to the fourth disclosure.

18 is an exemplary view showing a solution according to the fifth disclosure.

19 is a block diagram illustrating a wireless device and a base station in which the present disclosure is implemented.

20 is a detailed block diagram of a transceiver of the wireless device shown in FIG. 19.

Hereinafter, the present invention will be applied based on 3rd Generation Partnership Project (3GPP) 3GPP long term evolution (LTE) or 3GPP LTE-A (LTE-Avanced). This is merely an example, and the present invention can be applied to various wireless communication systems. Hereinafter, LTE includes LTE and / or LTE-A.

It is to be noted that the technical terms used herein are merely used to describe particular embodiments, and are not intended to limit the present invention. In addition, the technical terms used in the present specification should be interpreted as meanings generally understood by those skilled in the art unless they are specifically defined in this specification, and are overly inclusive. It should not be interpreted in the sense of or in the sense of being excessively reduced. In addition, when the technical terms used herein are incorrect technical terms that do not accurately represent the spirit of the present invention, it should be replaced with technical terms that can be understood correctly by those skilled in the art. In addition, the general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted in an excessively reduced sense.

Also, the singular forms used herein include the plural forms unless the context clearly indicates otherwise. In the present application, terms such as “consisting of” or “having” should not be construed as necessarily including all of the various components, or various steps described in the specification, and some of the components or some of the steps are included. It should be construed that it may not be, or may further include additional components or steps.

In addition, terms including ordinal numbers, such as first and second, as used herein may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but other components may be present in between. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In addition, in describing the present invention, when it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easily understanding the spirit of the present invention and should not be construed as limiting the spirit of the present invention by the accompanying drawings. The spirit of the present invention should be construed to extend to all changes, equivalents, and substitutes in addition to the accompanying drawings.

The term base station, which is used hereinafter, generally refers to a fixed station for communicating with a wireless device, and includes an evolved-nodeb (eNodeB), an evolved-nodeb (eNB), a base transceiver system (BTS), and an access point (e.g., a fixed station). Access Point) may be called.

Further, hereinafter, the term NB IoT device (User Equipment), which is used, may be fixed or mobile, and may include a device, a wireless device, a terminal, a mobile station, and a user (UT). terminal, subscriber station (SS), mobile terminal (MT), etc. may be referred to in other terms.

1 is a wireless communication system.

As can be seen with reference to FIG. 1, a wireless communication system includes at least one base station (BS) 20. Each base station 20 provides a communication service for a particular geographic area (generally called a cell) 20a, 20b, 20c. The cell can in turn be divided into a number of regions (called sectors).

The NB IoT device typically belongs to one cell, and the cell to which the NB IoT device belongs is called a serving cell. A base station that provides a communication service for a serving cell is called a serving BS. Since the wireless communication system is a cellular system, there are other cells adjacent to the serving cell. Another cell adjacent to the serving cell is called a neighbor cell. A base station that provides communication service for a neighbor cell is called a neighbor BS. The serving cell and the neighbor cell are determined relatively based on the NB IoT device.

Hereinafter, downlink means communication from the base station 20 to the NB IoT device 10, and uplink means communication from the NB IoT device 10 to the base station 20. In downlink, the transmitter may be part of the base station 20 and the receiver may be part of the NB IoT device 10. In uplink, the transmitter may be part of the NB IoT device 10 and the receiver may be part of the base station 20.

On the other hand, a wireless communication system can be largely divided into a frequency division duplex (FDD) method and a time division duplex (TDD) method. According to the FDD scheme, uplink transmission and downlink transmission are performed while occupying different frequency bands. According to the TDD scheme, uplink transmission and downlink transmission are performed at different times while occupying the same frequency band. The channel response of the TDD scheme is substantially reciprocal. This means that the downlink channel response and the uplink channel response are almost the same in a given frequency domain. Therefore, in a TDD based wireless communication system, the downlink channel response can be obtained from the uplink channel response. In the TDD scheme, since the uplink transmission and the downlink transmission are time-divided in the entire frequency band, the downlink transmission by the base station and the uplink transmission by the NB IoT device cannot be simultaneously performed. In a TDD system in which uplink transmission and downlink transmission are divided into subframe units, uplink transmission and downlink transmission are performed in different subframes.

Hereinafter, the LTE system will be described in more detail.

2 shows a structure of a radio frame according to FDD in 3GPP LTE.

Referring to FIG. 2, a radio frame includes 10 subframes (subframes), and one subframe includes two slots. Slots in a radio frame are numbered from 0 to 19 slots. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). TTI may be referred to as a scheduling unit for data transmission. For example, one radio frame may have a length of 10 ms, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms.

The structure of the radio frame is merely an example, and the number of subframes included in the radio frame or the number of slots included in the subframe may be variously changed.

Meanwhile, one slot may include a plurality of orthogonal frequency division multiplexing (OFDM) symbols. How many OFDM symbols are included in one slot may vary depending on a cyclic prefix (CP).

One slot includes N _RB resource blocks (RBs) in the frequency domain. For example, in the LTE system, the number of resource blocks (RBs), that is, N _RBs may be any one of 6 to 110.

A resource block (RB) is a resource allocation unit and includes a plurality of subcarriers in one slot. For example, if one slot includes 7 OFDM symbols in the time domain and the resource block includes 12 subcarriers in the frequency domain, one resource block may include 7Х12 resource elements (REs). Can be.

In 3GPP LTE, physical channels include a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), a physical downlink control channel (PDCCH), a physical control format indicator channel (PCFICH), and a physical hybrid (PHICH). ARQ Indicator Channel) and PUCCH (Physical Uplink Control Channel).

The uplink channel includes a PUSCH, a PUCCH, a sounding reference signal (SRS), and a physical random access channel (PRACH).

3 shows a structure of a downlink subframe.

In FIG. 3, 7 OFDM symbols are included in one slot by assuming a normal CP.

The DL (downlink) subframe is divided into a control region and a data region in the time domain. The control region includes up to three OFDM symbols preceding the first slot in the subframe, but the number of OFDM symbols included in the control region may be changed. A physical downlink control channel (PDCCH) and another control channel are allocated to the control region, and a PDSCH is allocated to the data region.

The PCFICH transmitted in the first OFDM symbol of a subframe carries a control format indicator (CFI) regarding the number of OFDM symbols (that is, the size of a control region) used for transmission of control channels in the subframe. The wireless device first receives the CFI on the PCFICH and then monitors the PDCCH.

Control information transmitted through the PDCCH is called downlink control information (DCI). DCI can be used for resource allocation of PDSCH (also called DL grant), PUSCH resource allocation (also known as UL uplink grant), and transmit power for individual NB IoT devices in any NB IoT device group. A set of control commands and / or activation of Voice over Internet Protocol (VoIP).

The base station determines the PDCCH format according to the DCI to be sent to the NB IoT device, and attaches a cyclic redundancy check (CRC) to the control information. The CRC masks a unique radio network temporary identifier (RNTI) according to the owner or purpose of the PDCCH. If the PDCCH for a specific NB IoT device, a unique identifier of the NB IoT device, for example, a cell-RNTI (C-RNTI) may be masked to the CRC. Alternatively, if the PDCCH is for a paging message, a paging indication identifier, for example, p-RNTI (P-RNTI), may be masked to the CRC. If the PDCCH is for a system information block (SIB), a system information identifier and a system information-RNTI (SI-RNTI) may be masked to the CRC. A random access-RNTI (RA-RNTI) may be masked in the CRC to indicate a random access response that is a response to the transmission of the random access preamble of the NB IoT device.

In 3GPP LTE, blind decoding is used to detect the PDCCH. Blind decoding is a method of demasking a desired identifier in a cyclic redundancy check (CRC) of a received PDCCH (referred to as a candidate PDCCH) and checking a CRC error to determine whether the corresponding PDCCH is its control channel. . The base station determines the PDCCH format according to the DCI to be sent to the wireless device, attaches the CRC to the DCI, and masks a unique identifier (RNTI) to the CRC according to the owner or purpose of the PDCCH.

<Discontinuous Reception (DRX)>

Now, Discontinuous Reception (DRX) is described in 3GPP LTE.

DRX is a technique for reducing the battery consumption of the wireless device by allowing the terminal to monitor the downlink channel discontinuously.

4 shows an example of a DRX cycle.

The DRX cycle specifies the periodic repetition of On-Duration followed by a possible interval of inactivity. The DRX cycle includes on- and off-sections. On-section is a device that the UE monitors the PDCCH in the DRX cycle.

If DRX is configured, the UE may monitor the PDCCH only in the on-section and may not monitor the PDCCH in the off-section.

The onDuration timer is used to define the on-section. The On-section may be defined as a section in which the onDuration timer is running. The onDuration timer specifies the number of consecutive PDCCH-subframes at the start of the DRX cycle. The PDCCH-subframe indicates a subframe in which the PDCCH is monitored.

In addition to the DRX cycle, a section in which the PDCCH is monitored may be further defined. A period in which the PDCCH is monitored is collectively defined as an active time. The active time may include an on-section for monitoring the PDCCH periodically and a section for monitoring the PDCCH due to an event occurrence.

<Carrier aggregation>

Now, a carrier aggregation (CA) system will be described.

The carrier aggregation system refers to aggregating a plurality of component carriers (CC). By the carrier aggregation, the meaning of the existing cell has been changed. According to carrier aggregation, a cell may mean a combination of a downlink component carrier and an uplink component carrier or a single downlink component carrier.

In the carrier aggregation, a cell may be divided into a primary cell, a secondary cell, and a serving cell. The primary cell means a cell operating at a primary frequency, and the NB IoT device performs an initial connection establishment procedure or a connection reestablishment procedure with the base station, or a handover procedure as a primary cell. It means the indicated cell. The secondary cell refers to a cell operating at the secondary frequency, and is established and used to provide additional radio resources once the RRC connection is established.

As described above, in the carrier aggregation system, unlike a single carrier system, a plurality of CCs, that is, a plurality of serving cells, may be supported.

Such a carrier aggregation system may support cross-carrier scheduling. Cross-carrier scheduling is a resource allocation of a PDSCH transmitted on another component carrier through a PDCCH transmitted on a specific component carrier and / or other components other than the component carrier basically linked with the specific component carrier. A scheduling method for resource allocation of a PUSCH transmitted through a carrier.

<Internet of Things (IoT) Communication>

Meanwhile, the IoT will be described below.

5A illustrates an example of Internet of Things (IoT) communication.

The IoT refers to the exchange of information through the base station 200 between the IoT devices 100 without human interaction or the exchange of information through the base station 200 between the IoT device 100 and the server 700. . As such, IoT communication is referred to as CIoT (Cellular Internet of Things) in that it communicates with a cellular base station.

Such IoT communication is a kind of machine type communication (MTC). Therefore, the IoT device may be referred to as an MTC device.

IoT services are differentiated from services in a communication involving a conventional person, and may include various categories of services such as tracking, metering, payment, medical field services, and remote control. For example, IoT services may include meter reading, water level measurement, the use of surveillance cameras, and inventory reporting on vending machines.

Since IoT communication has a small amount of data to be transmitted and rarely generates up and down data transmission and reception, it is desirable to lower the unit cost of the IoT device 100 and reduce battery consumption in accordance with a low data rate. In addition, since the IoT device 100 has a feature of low mobility, the IoT device 100 has a characteristic that the channel environment is hardly changed.

5B is an illustration of cell coverage extension or augmentation for IoT devices.

Recently, consideration has been given to extending or increasing cell coverage of a base station for the IoT device 100, and various techniques for expanding or increasing cell coverage have been discussed.

However, when the coverage of the cell is extended or increased, if the base station transmits a downlink channel to the IoT device located in the coverage extension (CE) or coverage enhancement (CE) area, the IoT device Will have difficulty receiving it. Similarly, if an IoT device located in the CE region simply transmits an uplink channel, the base station has difficulty receiving it.

In order to solve this problem, a downlink channel or an uplink channel may be repeatedly transmitted on several subframes. As described above, transmitting uplink / downlink channels repeatedly on a plurality of subframes is called a bundle transmission.

5C is an exemplary diagram illustrating an example of transmitting a bundle of downlink channels.

As can be seen with reference to FIG. 5C, the base station transmits a downlink channel (eg, PDCCH and / or PDSCH) to several subframes (eg, N subframes) to the IoT device 100 located in the coverage extension area. Repeated transmission on).

Then, the IoT device or the base station may increase the decoding success rate by receiving a bundle of downlink / uplink channels on various subframes and decoding some or all of the bundle.

6A and 6B are exemplary views illustrating examples of subbands in which an IoT device operates.

As one method for low-cost IoT devices, regardless of the system bandwidth of the cell, as shown in FIG. 6A, the IoT device may use a subband (subband) of, for example, about 1.4 MHz. Can be.

In this case, the region of the subband in which the IoT device operates may be located in the center region (eg, six PRBs) of the system bandwidth of the cell, as shown in FIG. 6A.

Alternatively, as illustrated in FIG. 6B, multiple subbands of an IoT device may be placed in one subframe for multiplexing in subframes between IoT devices, and different subbands between IoT devices may be used. At this time, most IoT devices may use a subband other than the center region (eg, six PRBs) of the system band of the cell.

Such IoT communication operating on the reduced bandwidth may be called NB (Narrow Band) IoT communication or NB CIoT communication.

7 shows an example of a time resource that can be used for NB-IoT in M-frame units.

Referring to FIG. 7, a frame that may be used for NB-IoT may be called an M-frame, and the length may be, for example, 60 ms. In addition, a subframe that can be used for NB IoT may be called an M-subframe, and the length may be 6ms for example. Thus, the M-frame may include ten M-subframes.

Each M-subframe may include two slots, and each slot may be 3ms for example.

However, unlike shown in FIG. 7, a slot that may be used for NB IoT may have a length of 2 ms, and thus a subframe may have a length of 4 ms and a frame may have a length of 40 ms. This will be described in more detail with reference to FIG. 7.

8 is another exemplary diagram illustrating time resources and frequency resources that can be used for NB IoT.

Referring to FIG. 8, a physical channel or a physical signal transmitted on a slot in an uplink of an NB-IoT includes N _symb ^UL SC-FDMA symbols in a time domain and is included in a frequency domain. N _sc ^UL subcarriers are included. The uplink physical channel may be divided into a narrowband physical uplink shared channel (NPUSCH) and a narrowband physical random access channel (NPRACH). In the NB-IoT, the physical signal may be a narrowband demodulation reference signal (NDMRS).

The uplink bandwidths of the N _sc ^UL subcarriers during the T _slot slot in NB-IoT are as follows.

Subcarrier spacing N _sc ^UL T _slot Δf = 3.75 kHz 48 61440 * T _s Δf = 15 kHz 12 15360 * T _s

In NB-IoT, each resource element (RE) of the resource grid is k = 0, ..., N _sc ^UL -1 and l = 0, ..., N _symb ^UL -1 day indicating the time domain and frequency domain In the slot, the downlink physical channel may be defined as an index pair (k, l) in the NB-IoT. Control Channel). The downlink physical signal includes a narrowband reference signal (NRS), a narrowband synchronization signal (NSS), and a narrowband positioning reference signal (NPRS). The NSS includes a narrowband primary synchronization signal (NPSS) and a narrowband secondary synchronization signal (NSSS). On the other hand, the NB-IoT reduces bandwidth according to low-complexity / low-cost. (Ie narrowband) is a communication scheme for wireless devices. This NB-IoT communication aims to allow a large number of wireless devices to be connected on the reduced bandwidth. Furthermore, NB-IoT communication aims to support wider cell coverage than cell coverage in the existing LTE communication.

Meanwhile, the carrier having the reduced bandwidth includes only one PRB when the subcarrier spacing is 15 kHz, as can be seen with reference to Table 1 above. That is, NB-IoT communication may be performed using only one PRB. Here, assuming that NPSS / NSSS / NPBCH / SIB-NB is transmitted from the base station, the PRB to which the wireless device connects to receive the base station may be referred to as an anchor PRB (or anchor carrier). Meanwhile, the wireless device may be allocated an additional PRB from a base station in addition to the anchor PRB (or anchor carrier). Herein, among the additional PRBs, the PRB which the wireless device does not expect to receive the NPSS / NSSS / NPBCH / SIB-NB from may be referred to as a non-anchor PRB (or non-anchor carrier).

<Paging>

The paging procedure is a procedure for switching the terminal to the RRC connected mode when there is downlink data to be delivered to the terminal in the RRC idle state.

9 is an exemplary view illustrating a paging procedure.

As can be seen with reference to FIG. 9, when the base station receives a paging signal from a mobility management entity (MME) (not shown), the base station is scrambled with a Paging Radio Network Temporary Identity (CR-RNTI). PDCCH (or MPDCCH or NPDCCH) with redundancy check) is transmitted. The base station transmits a PDSCH including a paging message.

If the UE succeeds in decoding the PDCCH (or MPDCCH or NPDCCH) having the CRC scrambled with the P-RNTI, the terminal decodes a paging message through the PDSCH. And, the terminal establishes an RRC connection procedure to enter the RRC connected mode.

As such, the terminal should monitor the PDCCH (or MPDCCH, or NPDCCH) in order to receive the paging message. However, when the monitoring period is short, the period in which the terminal performs blind decoding (BD) is shortened, resulting in an increase in power consumption.

Disclosure of the Invention

In order to solve the above-mentioned problem, the present disclosures propose introducing a new signal, such as a wake up signal (WUS). That is, the disclosures of the present specification propose methods for reducing power consumption of the terminal by utilizing WUS.

10A is a flowchart illustrating an example of utilizing WUS introduced according to the disclosure of the present specification, and FIG. 10B is an exemplary diagram illustrating WUS in the time domain.

As can be seen with reference to Figure 10a, the base station may transmit the WUS before transmitting the PDCCH (or MPDCCH or NPDCCH). Upon receiving the WUS, the wireless device may monitor the PDCCH (or MPDCCH or NPDCCH) to attempt to receive the paging message. One WUS may indicate that a plurality of paging messages are received. In this case, when the wireless device receives one WUS, the PDCCH (or MPDCCH or NPDCCH) may be monitored on several subframes in order to receive a plurality of paging messages.

Referring to FIG. 10B, a period during which the wireless device should monitor the WUS may be defined as a wake up signal occasion (WUSO). More specifically, the time interval in which the WUS actually exists in the time domain is called WUSO. In other words, the time interval during which the base station transmits the WUS may be referred to as a WUSO. The schemes presented herein can be applied to NB-IoT. Therefore, hereinafter, the disclosure of the present specification is described in view of an NB-IoT wireless device for monitoring NPDCCH for convenience of explanation. However, the disclosures herein are generally applicable to other systems using wake up signal (WUS). In addition, the following description will focus on the operation of performing the monitor and blind decoding of the NPDCCH to receive a paging message for convenience of description, the disclosure of the present specification to perform a blind decoding of a general physical channel, to reduce power consumption Can be applied. For example, the method described herein may be applied to a process of monitoring a UE-specific search space (USS) when the wireless device in the RRC connected mode maintains the C-DRX mode.

In addition, the following description focuses on an operation in which the base station transmits a WUS to the wireless device so that the wireless device wakes up after monitoring the NPDCCH, but the operation is performed so that the wireless device does not monitor the NPDCCH. The same may be applied to go to sleep operations (or signals).

I. First Initiation: Information Included in WUS

This section proposes a scheme for transmitting specific information using WUS.

The information may be expressed in sequence form. For example, a WUS can be expressed using a sequence of the form Zadoff-Chu. For example, it may be possible to distinguish information by the position of a sequence in the time domain. Alternatively, the method of expressing the information may be a tone selection based method. In detail, information may be classified through a pattern of hopping a tone within a specific time domain. This may be the same way as the frequency hopping pattern used for NPRACH. Alternatively, the method of expressing information may use symbol positions (or other resource units in a distinguishable time domain) in which a specific sequence exists. For example, when the m-th sequence is located in the l-th symbol and the l`-th symbol in one subframe, information represented by each other may be different. Alternatively, as a method of expressing the information, a method of expressing information based on a form such as NPDCCH or PHICH may be used. Alternatively, as a method of representing information, a method of expressing information included in the WUS using a physical channel such as DCI may be used.

When information is represented using the WUS, the information may be used for the purpose of indicating a frequency resource domain for receiving a paging message after the wireless device receives the WUS. Herein, the time interval in which the paging message exists may be referred to as a paging occasion (PO). That is, the PO means a time interval in which the base station transmits a paging message. The PO may indicate a specific subframe, not a time interval. In other words, a subframe in which transmission of the paging message starts may be referred to as PO. The wireless device receives the paging message in the PO section. This may be for the purpose of enabling the base station to temporarily control the load of paging using WUS. When information is represented using WUS, the information may be used for the purpose of indicating update of system information (eg, MIB or SIB). For example, in the case of information whose contents are not frequently changed, such as NPBCH or NB-SIB1 in NB-IoT, the wireless device reads the WUS before reading the NPBCH or NB-SIB1. You can know in advance whether the information has changed. For another example, when a wireless device in an RRC suspend mode switches to an RRC connected mode, the wireless device may be used for notifying whether RRC signaling is updated. This may be aimed at reducing power consumption and latency of the wireless device by reducing the acquisition time of system information.

When expressing specific information using WUS, the information may be for subdividing an identifier (eg, UE_ID) or a group identifier of a wireless device that should receive paging. For example, wireless devices performing monitoring in the same WUSO may belong to a group performing monitoring in the same PO time interval. As another example, the base station may use information included in the WUS for the purpose of subdividing the wireless devices for actually transmitting paging into detailed groups among the wireless devices in one group. More specifically, for example, if there are a total of N wireless devices that perform monitoring during a specific PO time interval and want to divide it into M subgroups again, the WUS may include a total of M pieces of information that can be distinguished from each other. At this time, if the wireless device receives the WUS by monitoring the WUSO, the wireless device can find out the information on the subgroup to which it belongs from the information included in the WUS.

Ways of expressing information using WUS may exist in various ways in addition to the above-described methods, and some examples thereof will be described later.

II. Second opening: setting up WUSO

A specific interval for monitoring WUS can be defined as a WUSO window. Specifically, this will be described with reference to FIG. 11. In other words, a time interval in which monitoring should be performed to receive a WUS may be defined as a WUSO window.

11 is an exemplary view showing a WUSO window on a time axis.

As can be seen with reference to FIG. 11, the time interval in which the WUS actually exists in the WUSO window is a WUSO as described above.

In this case, the wireless device may monitor the WUS for possible subframes within the WUSO window. The size of the WUSO window may include one or more subframes. In this case, information on the size and number of subframes may be indicated through an upper layer signal. Alternatively, the size of the subframe may be indicated through the information contained in the WUS. Alternatively, the WUSO may be in units of several symbols or slots. The WUSO window may be set to absolute time. In this case, the absolute time may mean the number of consecutive subframes regardless of whether the subframe is valid. In this case, the WUS may be determined to be transmitted in a valid subframe within the WUSO window. On the contrary, if the length of the WUSO window is determined based on the number of valid subframes, the WUSO window may have the same meaning as the subframe in which the actual WUS is transmitted. In this section, for convenience of explanation, the following description is used to describe the WUSO window and WUSO.

The frequency domain resource in which the WUSO to be monitored by the wireless device exists may be the same area as the frequency domain resource in which a paging message to be monitored is received. Characteristically, in the NB-IoT, the wireless device may be arranged to monitor the WUSO on the same carrier as the anchor (or non-anchor) carrier that monitors the paging message. This is to reduce the power consumed by the wireless device to perform frequency readjustment when the frequency resource is changed.

The WUSO can be arranged to occur at regular intervals. For example, the period of the WUSO may be determined as a fixed time (or number of subframes) through a higher layer signal. In this case, all the wireless devices can apply the same period set by the higher layer signal. Alternatively, the period of the WUSO may be determined by a specific value for each wireless device. If the wireless device is set to the WUSO period common to all wireless devices by the upper layer signal, and the WUSO is set to a specific value for each wireless device, the wireless device and / or the base station is set to the period and the wireless device through the higher layer signal It may be assumed that the period of the WUSO is set based on a shorter period among specific periods. Alternatively, the period of the WUSO may be indicated through information contained in the WUS. The manner in which the period of the WUSO is expressed may represent an absolute time (or the number of subframes) or may be determined by the number of POs that may occur between two WUSOs. When the period of the WUSO is expressed by the number of POs, the period may be set in the form of a multiple of the period of the PO.

If the WUSO is set only in a valid subframe, if the WUSO collides with or partially or completely overlaps the location of the invalid subframe, the WUSO may be set to postpone after the invalid subframe. have. If the wireless device detects a WUS assigned to it during WUSO, if the PO and WUSO collide or overlap some or all of the time resources within the interval of the paging window indicated by WUS, the wireless device gives up WUSO and PO Monitoring can be performed during the time interval. That is, when the reception of the WUS is abandoned, the reception of the paging message may be monitored during the PO corresponding to the WUSO, regardless of whether the WUS is transmitted in the WUSO. This may be for the purpose of lowering the power consumption of the wireless device, and the base station may assume this operation of the wireless device and schedule the WUSO. If the WUSO and PO collide or overlap some or all of the time resources in a section other than the paging window indicated by the WUS, the wireless device may be arranged to monitor the WUSO.

Alternatively, in a situation where the WUSO is determined to operate only in a valid subframe, when the WUSO collides with a location of an invalid subframe or overlaps some or all of the time resources, the WUSO may be determined to drop. In this case, even if the WUS is not sent when performing an operation such as go to sleep, the probability that the wireless device misses the paging message allocated to the wireless device does not increase.

PO may not exist during a certain gap before the interval in which the WUSO is set. That is, the paging message may not be attempted during the specific gap period. This may be for ensuring the time for blind decoding the NPDCCH in the PO. If the gap is set to be the n _{gap_p_to_w} subframe based on the downlink subframe, the paging window may be determined to include only the n _{gap_p_to_w} subframe before the generation time of the _WUSO . Alternatively, even if the paging window includes a section set as a gap, the wireless device may be determined not to expect a PO in this section. In this case, the size of the gap may apply the same period set by the higher layer signal. Alternatively, the size of the gap may be indicated through the information contained in the WUS.

Alternatively, the WUSO may not exist during a specific gap after the interval in which the PO is set. That is, the WUS may not be attempted during the specific gap period. This may be for ensuring the time for blind decoding the NPDCCH in the PO. In this case, even if the WUS is not monitored when performing an operation such as go to sleep, the probability that the wireless device misses the paging message allocated to the wireless device does not increase.

 If the WUSO and a specific purpose search space (eg, common search space (CSS) or USS) collide or overlap some or all of the time resources, the terminal may be determined not to attempt to receive the WUS during the WUSO. Instead, the UE may assume that a PDCCH (or NPDCCH) may be transmitted even when the WUS is not transmitted from the base station during the corresponding WUSO. For example, the search space for a specific purpose may be a purpose for receiving a RAR, or a location set for SC-PtM operation. The statements can be made to apply only to a specific WUS design when more than one type of WUS design is used. For example, suppose that both a design where WUS can be used for synchronous purposes and a design that does not are available. If one or a combination of the two designs is determined by the determination of the base station, the above-mentioned information may be determined to be applied to the WUS not used for synchronization purposes only. In this case, WUS, which is not used for synchronization purposes, refers to a design that is not easy for a wireless device to use for receiving a synchronization signal, and must not be used for acquiring a synchronization signal or that a corresponding function does not exist. It does not mean. For example, this is the case for a long ZC sequence in which RE mapping is performed over several OFDM symbols such as NSSS.

Alternatively, when the WUS collides with another signal or channel or when some or all overlaps occur in a time resource, it may be determined whether puncturing or dropping is applied according to the extent of the collision. For example, if the collision with other CSS is small, puncturing is applied, drop the WUS only when the collision exceeds a certain size, and assume that the NPDCCH can be transmitted without transmitting the WUS. Can be decided. Meanwhile, puncturing may be applied to wireless devices located in a specific coverage extension area and repeating reception. In the case of dropping, when the size to be punctured is excessively large, it may be the purpose of preventing transmission of meaningless WUS from the viewpoint of the base station. In addition, in the case of abandonment, it may be an object to prevent performance degradation due to short WUS from the perspective of the wireless device. Here, the criterion for determining either puncturing and abandonment may be determined by the absolute number of time domain units (eg, symbols or subframes) in which the collision of the WUS occurs. Alternatively, in the above description, a criterion for determining puncturing or abandonment may be determined based on a rate at which a collision occurs based on a set interval of WUS. The reference values may be predetermined fixed values or may be set by the base station and instructed by the wireless device through higher layer signals.

Among the contents described above, the definition and setting for the paging window follows the contents described in the second disclosure. If the system does not require a paging window, the paging window may have the same meaning as all the intervals for monitoring the PO between WUSOs, even if there is no definition.

The method of determining the WUSO may be one of the methods described below.

II-1: First Plan of Second Disclosure

The WUSO window may be defined as an offset n _{w_offset} relative to a paging occasion (PO).

12A is an exemplary diagram illustrating a first scheme of the second disclosure.

Referring to FIG. 12A, a method of determining a WUSO window according to the first method of the second disclosure is illustrated. However, other types of approaches using WUS are possible, other than shown.

For example, when the PO is set in a specific n th subframe, the start subframe of the WUSO window may be determined as the nn _{w_offset} th subframe. In this _case, the value of n _{w_offset} may be a value set as an upper layer parameter. If the value of n _{w_offset} is not set, the wireless device may use a predetermined default value. Alternatively, the value of n _{w_offset} may be a value determined by an identifier (eg, UE_ID) of the wireless device. In this case, the identifier (eg, UE_ID) of the wireless device used to determine the PO may be broken down to set the WUSO window. For example, the value of n _{w_offset} that determines the WUSO window based on the identifier (eg, UE_ID) of the wireless device may be defined by the following equation.

In this case, f (x) is a function corresponding to the value of n _{w_offset} and x and may exist in the form of a predefined table. In this case, α may be used for the purpose of dividing the wireless devices having the identifier (eg, UE_ID) of the wireless device into α subgroups by a specific constant value. In this case, α may be indicated through information expressed using higher layer signals and / or WUS.

Alternatively, the value of n _{w_offset} may be indicated through information contained in the WUS. In this case, the indicated value of n _{w_offset} may be for controlling the WUSO to be monitored by the wireless device afterwards. For example, if the information on n _{w_offset} contained in the WUS is A, the value of n _{w_offset} that determines the WUSO based on the information may be defined by the following equation.

In this case, f (x) is a function corresponding to the value of n _{w_offset} and x and may exist in the form of a predefined table.

The value of n _{w_offset} defined above may be _counted based on valid subframes only. This may be for preventing a case where a gap between the WUSO and the PO varies according to the number of invalid subframes or a sufficient repetition of the WUS is not obtained. Alternatively, the value of n _{w_offset} defined above may be _counted in absolute time units. This may be counting all subframes without valid / invalid subframe division. This may be for preventing the WUSO starting subframe location from varying according to the number of invalid subframes, so that the time between the WUS monitoring and the reception of the paging message is excessively long.

The period at which the WUSO window occurs may have a different value from the period at which the PO occurs. If the period in which the window WUSO occurs that is defined as a _period T, WUSO can be determined to occur at a position offset of PO generated every T _period. For example, the size of the T _period may have a value equal to the eDRX value. In this case, when the wireless device in the sleep mode by the eDRX size starts the active mode, it may be used for the purpose of determining whether to monitor the NPDCCH in the corresponding active mode interval. If a wake up is not detected in the corresponding WUSO or a go to sleep command is detected, the wireless device may not perform NPDCCH monitoring in the corresponding active mode section.

If the starting subframe position of the WUS determined by the offset is an invalid subframe, the starting subframe position of the WUS may be determined as the nearest valid subframe position appearing after the subframe position designated by the offset. Alternatively, the starting subframe position may be determined to be the same, and instead, puncturing an invalid subframe period.

The description may be modified to determine the end time (or ending occasion) of the WUSO window based on the offset. This may be to ensure that the gap between the WUSO window and the PO is always a certain size. In this case, the size of the gap may be an absolute time, which may be counting the number of all subframes without distinguishing between valid and invalid subframes.

The proposed schemes can be modified such that the start offset for setting the start subframe and the end offset for setting the end subframe are used simultaneously. Specifically, it will be described with reference to Figure 12b.

12B shows a variant of the first scheme of the second disclosure.

As shown in FIG. 12B, the WUSO window may be determined as a section between a position indicated by the start offset n _{w_offset_start} and a position indicated by the end offset n _{w_offset_end} . In this case, the transmission of the WUS may be transmitted to start based on the start subframe position of the WUSO or to end based on the end subframe position. If the number of valid subframes for performing the WUS repetition is insufficient within the interval of the WUSO, the WUS may be determined to be transmitted as much as possible without using all the repetitions.

II-2: Second Plan of Second Disclosure

Another way to determine the WUSO may be to use a fixed location determined by the higher layer signal. For example, the location of the WUSO may be indicated in the form of a bit map through the SIB. In this case, the subframe corresponding to the WUSO may be set to an invalid subframe. As another example, the location of the WUSO may be indicated through the SIB to appear every specific period. In this case, there is an advantage that the overhead of expressing the position corresponding to the WUSO can be reduced. The two examples presented above may each be used independently or in a combined manner.

Possible positions of the WUSO indicated through the higher layer signal may be selectively used by subdividing by the identifier (eg, UE_ID) of the wireless device. For example, if the total number of possible locations of the WUSO indicated by the higher layer signal is N, the identifier of the wireless device (eg, UE_ID) may be divided into a total of M subgroups. At this time, the size of M is smaller than N, and a value obtained by dividing N by an arbitrary integer may be used. In this case, the same number of WUSOs may be mapped to each subgroup. For example, when there are N available WUSO positions, a detailed group for monitoring the n _{w_HLS} th positions may be determined to satisfy a condition of the following equation.

In this case, the M value may be indicated to the wireless device through information expressed using higher layer signals and / or WUS.

Possible positions of the WUSO indicated through the higher layer signal may be selectively used by subdividing by the identifier (eg, UE_ID) of the wireless device. For example, when the size of the bitmap represented by the higher layer signal is N _bm , the wireless device may be divided into a total of M subgroups. At this time, the size of M is smaller than N, and a value obtained by dividing N by an arbitrary integer may be used. At this time, different number of WUSO can be mapped to each subgroup. For example, N _bm When used, the bitmap of size n _{w_HLS} subgroup to monitor the second position can be determined so as to satisfy the following equation in the same conditions.

In this case, the M value may be indicated to the wireless device through information expressed using higher layer signals and / or WUS.

13 is an exemplary view illustrating a second scheme of the second disclosure.

Referring to FIG. 13, according to the second method of the second disclosure, a method of determining a paging window using WUS is illustrated. However, other types of approaches using WUS are possible, other than shown.

II-3: Third Plan of Second Disclosure

II-3-1: First example of the third scheme of the second disclosure

Another way to determine WUSO is to reuse existing PO definitions. At this time, a part of the PO may be used as a WUSO and a part of the PO may be used as a PO. This scheme can be seen as a special case of the first scheme. If, as in the first scheme, only a single WUSO is used without segmentation within a group sharing the same PO, the value of n _{w_offset} has the same effect as the scheme of setting zero. If the segmentation is applied in a group sharing the same PO as in the first scheme, the value of n _{w_offset} may be determined as any one of integer multiples of the periodic paging DRX of the PO. For example, the value of n w_offset that determines the _WUSO may be defined by the following equation.

In this case, α represents the number of subgroups for subdividing the wireless devices having the identifier (eg, UE_ID) of the wireless device with a specific constant value. In this case, the c value may be an arbitrary integer value as a specific constant value and may be designated through information expressed using higher layer parameters and / or WUS. Alternatively, the c value may be a predefined fixed value.

If the position used as the WUSO collides with a channel or subframe for another purpose, the WUSO may be determined to be deferred to the position of the next PO.

If the described approach is applied, the wireless device may attempt to detect both WUS and paging in the PO designated as WUSO. This may be aimed at ensuring flexibility by allowing the base station to transmit paging without sending a WUS at a location designated as the WUSO.

The first example described may be for ensuring flexibility for a wireless device in an RRC connected mode.

14 is an exemplary view showing a first example of the third scheme of the second disclosure.

Referring to FIG. 14, according to the first example of the third method of the second disclosure, a method of determining a paging window using WUS is illustrated. However, other types of approaches using WUS are possible, other than shown.

II-3-2: Second Example of Third Plan of Second Disclosure

In the scheme of using an existing PO as a WUSO, the position where the WUSO appears may be determined to use a fixed position determined by a higher layer signal. For example, the location of the WUSO may be indicated in the form of a bitmap through the SIB. This solution can be seen as special to the second solution. In this case, the subframe indexes represented by the bitmap may be targeted to only subframes set to PO. In this case, if the number of subframes represented by the bitmap is N _PO, each bit represents N _PO POs. If segmentation is applied to a group of wireless devices that share the same PO as in the second method, the subgroup using n _{w_offset} th PO as a WUSO may be determined to satisfy a condition of the following equation.

In this case, the M value may be indicated to the wireless device through information expressed using higher layer signals and / or WUS.

If the above scheme is applied, the wireless device may attempt to detect both WUS and paging in a PO designated as WUSO. This may be for ensuring flexibility by allowing the base station to transmit paging without sending a WUS at a location designated as the WUSO.

15 is an exemplary diagram illustrating a second example of the third scheme of the second disclosure.

Referring to FIG. 15, a method of determining a paging window using WUS is shown according to a second example of the third method of the second disclosure. However, other types of approaches using WUS are possible, other than shown.

II-3-3: Third example of third scheme of second disclosure

In the scheme of using an existing PO as a WUSO, the position at which the WUSO appears may be determined to be freely set by the base station. In this scheme, the wireless device determines that WUSO is possible in all POs. Therefore, the wireless device may perform all operations for monitoring WUS or monitoring paging in the PO or select one operation. This may be for instructing a specific group of wireless devices to change specific information related to paging using WUS. At this time, it may be determined to use a PO that is already set up without allocating a separate resource for the WUSO.

16 is an exemplary view showing a third example of the third scheme of the second disclosure.

Referring to FIG. 16, according to a third example of the third method of the second disclosure, a method of determining a paging window using WUS is illustrated.

When the first, second, and third examples described are used and the WUS is designed as a physical channel using DCI, the bit size of the corresponding DCI format is equal to the DCI format bit size of the NPDCCH transmitted to the PO used by the WUSO. It can be determined to have a value. This may be for the wireless device in the WUSO to monitor both the WUS and the existing NPDCCH without increasing blind decoding.

II-4: Fourth Scheme of the Second Disclosure

The WUSO may be determined to be transmitted in a subframe, such as a subframe in which a synchronization signal is transmitted, or in an adjacent subframe. This may be for the purpose of increasing the accuracy of time synchronization in acquiring the WUSO, or reducing the delay that may occur between the operation of the WUSO monitoring and the acquisition of the synchronization signal. For example, the WUSO may be determined to be formed in the subframe in which the PSS or SSS is transmitted. As another example, the WUSO may be determined to be formed in a subframe adjacent to the subframe in which the NPSS or NSSS is transmitted.

In the proposed scheme, the position of the WUSO may be determined to select the same or adjacent subframe as the PSS / SSS (or NPSS / NSSS) closest to the PO corresponding to the WUSO. This may be aimed at minimizing the time delay spent in acquiring the synchronization signal, monitoring the WUSO, and monitoring the paging.

II-5: Fifth Scheme of the Second Disclosure

When the TDD structure is applied, the position of the WUSO may use the position of a special subframe.

In this case, whether to apply (or set) the WUSO may be determined according to the special subframe configuration information. In this case, the wireless device may determine whether the WUSO is set / applied through the configuration information of the special subframe. For example, in the case of a special subframe setting having a short length of DwPTS, the wireless device may determine that the base station does not transmit the WUS. The wireless device may determine that the WUSO is set in the case of setting a special subframe having a long DwPTS.

When the special subframe is set for the use of the WUSO, the WUSO may be set to be set at a specific period. To this end, the base station may instruct the wireless device information about the start position and the period. The indication may be performed through higher layer signals such as SIB or RRC signals. In this case, the corresponding information may be determined wirelessly or group-specifically of the wireless device. The determined location of the WUSO may estimate the location of the WUSO based on information informed by the base station and the wireless device's own identifier (eg, UE ID). Alternatively, the special subframe used for the WUSO may include only specific special subframes. To this end, a method of indicating a subframe number or a radio frame number may be used, or a form such as a bitmap may be used. In this case, the corresponding information may be determined specifically for the wireless device or for the group-specific group of the wireless device.

If two special subframes exist in one radio frame and only one of them is used as the WUSO, the corresponding position may be determined dependent on the position where the synchronization signal is transmitted. For example, when it is necessary to acquire the downlink synchronization signal before the detection of the WUS, the position of the WUSO may be determined as the closest special subframe position among the subframes following the SSS (or NSSS). This may be aimed at minimizing the time delay consumed after acquiring the synchronization signal and monitoring the WUS. In the opposite case, for example, the WUS can be detected without an accurate downlink synchronization signal, but if the downlink time synchronization needs to be accurately adjusted to monitor the downlink channel after the WUS, the position of the WUSO is located before the SSS (or NSSS). It may be determined as the location of the closest special subframe among the subframes. This may be aimed at minimizing the time delay consumed after acquiring the WUS and acquiring the downlink synchronization signal.

If the special subframe is used for WUSO purposes, the wireless device may determine whether to monitor the WUS according to its coverage extension level. In this case, special subframe configuration information may be used as another condition for determining whether to monitor. For example, the wireless device may abandon the WUSO monitoring if it determines that its coverage extension level is above a certain threshold value through its RSRP. In this case, the threshold value may be changed according to the special subframe configuration. This may be for the purpose of preparing a case where it is difficult to acquire WUS for a wireless device located in a high coverage extension area in a situation in which the length of the special subframe is limited and the repeated reception is limited.

III. Third initiation: an instruction to the paging window or PO

This section proposes a method of using the WUS for the purpose of indicating a paging window and / or PO for the wireless device to perform NPDCCH monitoring. The wireless device may monitor the WUSO assigned to it and determine whether there is a paging window and / or PO that it should monitor. In this case, the paging window is defined as a period in which the wireless device monitors the PO in order to read the paging message. In this case, the WUS is used for instructing a wake up operation of the wireless device. Alternatively, the paging window may be used as a section in which the wireless device does not monitor the PO. In this case, the WUS is used for instructing go to sleep of the wireless device. There may be one or more POs in one paging window. The wireless device monitors the NPDCCH for POs that may occur in the paging window.

The location where the paging window is set may be determined to be after a certain gap from the WUSO. This gap may be for the wireless device to prepare for detecting WUSO and monitoring paging. Or it may be for the purpose of giving flexibility to the scheduling of the WUSO and PO. In this case, the size of the gap may be determined through a higher layer signal. If not, the gap size may be determined according to a default value. Alternatively, the size of the gap may be indicated through the information contained in the WUS. For example, this gap may be determined to be an n _{gap_w_to_p} subframe based on a downlink subframe. In the case of a paging window, even if an invalid subframe is included in the middle, the interval may be determined so as not to change.

The wireless device may not expect the generation of PO in a section other than the paging window. This may be for the purpose of reducing the burden of blind decoding performed by the wireless device by limiting the section in which the actual base station can transmit the paging message. The paging window may be defined as the interval from after the WUSO is monitored (or from the time the gap is applied after the WUSO is monitored) before the next WUSO occurs. In this case, the wireless device has an advantage of determining a paging window without acquiring a separate signal. Alternatively, the paging window may include an interval set through higher layer parameters from after the WUSO is monitored (or from the time the gap is applied after the WUSO is monitored). In this case, by limiting the location of the PO to be monitored by the wireless device, the power consumption due to blind decoding can be reduced.

IV. 4th Initiation: Control of the DRX Cycle

This section proposes a way to use the WUS for the purpose of controlling the paging DRX cycle in which the wireless device performs NPDCCH monitoring. The wireless device may monitor the WUSO assigned to the wireless device and determine the period of the PO through which the base station transmits the actual NPDCCH. This is to reduce the DRX cycle of some wireless devices while maintaining the paging DRX cycle in terms of the entire cell, if the paging demand of a particular wireless device or a certain group of wireless devices is higher than other wireless devices during a certain period. May be the purpose. Or conversely, during a certain period, if the paging demand of a particular wireless device or of a certain group of wireless devices is less than other wireless devices, the DRX cycle of some wireless devices may be increased while maintaining a paging DRX cycle from an overall cell perspective. It may be for the purpose.

For example, in a situation where the _PO period is determined as T _PO , the wireless device that detects the WUS may use the new PO period T _{PO_new} . In this case, T _{PO_new} may be determined as a constant multiple of T _PO . In this case, the following equation may be followed.

In this case, the c value may be designated through information expressed using a higher layer signal and / or a WUS as a constant value. Alternatively, the C value may be a fixed value. Alternatively, the T _{PO_new} value may be designated through information expressed through higher layer signals and / or WUS. Alternatively, the T _{PO_new} value may be a predetermined fixed value.

When using the method proposed in this section, the section to which the new T _{PO_new} is applied after detecting the WUS can be limited to within a certain subframe after detecting the WUS. In this case, this section may be determined by a higher layer parameter. Alternatively, the size of this section may be indicated through the information contained in the WUS. This may be for the purpose of allowing the wireless device to perform normal operation again by applying the original period T _PO again after a certain period even if the WUS fails to detect the WUS. Alternatively, the interval to which T _{PO_new} is applied may be limited to within a predetermined subframe after adding a delay as much as a predetermined gap at the time of detecting the WUS.

17 is an exemplary view showing a solution according to the fourth disclosure.

Assume that the subframe index where the WUS is detected is n. As shown in FIG. 17, when the size of the gap set after the WUS before monitoring the PO is n _{gap_w_to_p} and the length of the subframe interval to which T _{PO_new} is applied is n _{PO_new} , a time point at which a new period is started is n +. when n _{gap_w_to_p} and ends can be determined by n + n _{gap_w_to_p} + n _{PO_new.} If this section is not defined or if the wireless device fails to acquire the information, the wireless device may determine the section as the point in time at which the next WUS is detected.

When using the method proposed in this section, if the position of the WUSO is determined relative to the PO, the position of the WUSO can be determined based on the original PO period T _PO only. This may be a method for preventing the wireless device from missing the next WUSO even if the wireless device fails to monitor the WUS. Alternatively, as another method for the same purpose, the location of the _WUSO may be selected based on a larger value of the values of T _PO and T _{PO_new} .

The scheme proposed in this section can be applied for the purpose of instructing the wireless device not to perform paging monitoring for a certain period of time. In this case, when T _{PO_new} is regarded as infinite or T _{PO_new} is set to a value larger than the interval n _{PO_new} to which the value of T _{PO_new} is applied, the base station has the same effect. Alternatively, when the wireless device detects the WUS in the WUSO corresponding to the wireless device, the paging may not be monitored for a predetermined period. When the WUSO occurs in a section in which the wireless device does not perform paging monitoring, the wireless device may be configured to monitor the WUS. This may be for the purpose of reflecting when information on paging monitoring is changed. The interval for not performing paging monitoring may be determined through higher layer signals. Alternatively, a section in which no paging monitoring is performed may be indicated through information contained in the WUS. For example, the corresponding interval may be represented by the number of consecutive subframes. Or it may be represented by the number of PO. If the wireless device does not acquire the corresponding information or there is no information to be set, the wireless device may operate based on a predetermined fixed value.

V. Fifth Initiation: Additional PO Instructions

This section proposes the use of WUS to temporarily add POs to wireless devices. In this case, the added PO may have a method independent of the determination method of the cell common PO that the wireless device has previously. For example, assuming that the subframe index of the PO determined as the cell common PO is a period T _c based on n _c , the subframe index of the added PO may have a period T _add based on n _add . . This may be aimed at ensuring the flexibility of the PO in a situation where the paging demand for a particular wireless device or a specific group of wireless devices is temporarily increased.

After the wireless device detects the WUS, the position where the additional PO starts may be after a subframe of a predetermined size in the subframe in which the WUS is detected. In this case, an interval between subframe positions of the additional PO from the subframe from which the WUS is detected may be set through a higher layer signal. Alternatively, the interval between subframe positions of the additional PO from the subframe in which the WUS is detected may be indicated through information contained in the WUS.

When using the scheme proposed in this section, the interval for monitoring PO added after detecting WUS can be limited to within a certain subframe after detecting WUS. In this case, this section may be determined by a higher layer parameter. Alternatively, this section may be indicated through information contained in the WUS. This may be for the purpose of allowing the wireless device to monitor the original PO again after a certain period even if the wireless device fails to detect the WUS. Alternatively, the wireless device may be able to suspend additional POs by themselves even if they do not receive a separate release signal.

18 is an exemplary view showing a solution according to the fifth disclosure.

As shown in FIG. 18, when the gap for designating a subframe in which an additional PO is started is n _{start_add} and the size of the subframe interval in which additional POs are monitored is defined as n _{dur_add} , The wireless device that detects the corresponding WUS may monitor additional POs in subframes from n0 + n _{start_add} to n0 + n _{start_add} + n _{dur_add} .

According to the method proposed in this section, when the wireless device detects a WUS indicating additional PO, the new PO may be monitored without monitoring the existing PO. This may be aimed at reconfiguring the PO while minimizing an increase in blind decoding of the wireless device when a location of the PO is advantageous to a specific wireless device or a specific group of wireless devices in view of scheduling flexibility.

VI. 6th opening: WUS design

The radio resource used to transmit the generated WUS may be defined in block units consisting of one or more REs. In the following description, a block used by one WUS is referred to as a wake up signal block (WUSB). In this case, if the WUS has a sequence structure, the WUSB may have one or more sequences grouped together.

VI-1: First Scheme of the Sixth Disclosure: Repetitive Size of WUSB

This section includes ways to determine the size at which WUSB repeats. The repetitive size of WUSB can be used in one of the following ways. In the following description, a description has been made as a method of determining a repetition unit of the WUSB, but the same may also be used as a method of determining a section in which a WUS is transmitted in the time domain.

(First Embodiment) The size of the repetition of the WUSB may be determined by an upper layer parameter set for paging. This may be for the purpose of enabling the wireless device that detects the WUS to detect paging as well. The size of the repetition of the WUSB may be a certain positive integer value that is mapped through a higher layer parameter defined for paging. For example, the repetition size of the WUSB may have a value equal to the repetition size of the paging. As another example, for NB-IoT, the repetition size of the WUSB may be determined as a function of R _max set for paging.

(Second Embodiment) Even if the method of using the repetition size of the WUSB in the same manner as the repetition set for paging is used, the maximum repetition size of the WUSB may be determined not to exceed a predetermined size. This may be to reduce the power consumption required for the wireless device to monitor the WUSB.

(Third Embodiment) The size of the repetition of the WUSB may be indicated through an upper layer signal set for the WUS. For example, corresponding information may be transmitted through a signal that can be acquired by a wireless device in an RRC IDLE state such as an SIB.

(Fourth Embodiment) The repetition size of the WUSB may be determined by a combination of a higher layer parameter set for WUS and a higher layer parameter set for paging. This may be for the purpose of supporting an appropriate repetition level while reducing the overhead of information for setting the repetition level of the WUS. The specific method of applying this may be one of the following two options.

(Option 1 in Embodiment 4) When the upper layer parameter for setting the repetition of the WUSB is represented by N bits, the repetition number represented by using N bits is determined by the number of repetitions used for paging. Can be determined. For example, suppose that the value of the number of repetitions corresponding to N bits representing the upper layer parameter for setting the repetition of the WUSB exists in the form of a table. The table may be different depending on a section to which the R _max value which determines the number of repetitions of paging belongs.

(Option 2 in Embodiment 4) When the upper layer parameter for setting the repetition of the WUSB is represented by N bits, the value interpreted using the N bits may be a certain positive integer value R _mp . In this case, when the upper layer parameter value used to determine the number of repetitions of paging is R _max , the repetition value of WUSB may be determined as R _mn * R _max .

(Fifth Embodiment) The repetition level of the WUS may be set differently for each carrier. This may be due to a difference in transmission resources available for each carrier or different radio channel environments. For example, the repetition level of the anchor carrier and the repetition level of the non-anchor carrier may be different from each other. In this case, a method of independently setting the repetition level of each carrier through an upper layer signal may be used. Alternatively, the repetition level of the non-anchor carrier may be designated as a multiple of the anchor carrier. In this case, the repetition level and multiple of the anchor carrier may be indicated by a higher layer signal. Alternatively, when different Rmax values of respective carriers are designated and repetition levels are determined dependently, different WUS repetition levels may be determined.

VI-2: Second Plan of the Sixth Disclosure: Size of WUSB

This section describes how the size of WUSB is set by the base station. For example, when the WUS is in the form of a sequence, the size of the WUSB may be determined by the length of the sequence used by the base station. In this case, the wireless device may estimate the length of the sequence to be used according to the size of the set WUSB. The size of the WUSB can be used in one of the following ways, or in combination with one or more embodiments.

(First Embodiment) The size of the WUSB may be determined as a function of a higher layer parameter that sets the repeat size of the WUSB (or paging), or the repeat size of the WUSB (or paging). For example, in the case of NB-IoT, the size of WUSB may be determined as a function of R _max set for paging.

(Second Embodiment) The size of the WUSB may be determined through an upper layer parameter set for the size of the WUSB. For example, the corresponding information may be transmitted through a signal such as an SIB that can be acquired by a wireless device in an RRC IDLE state.

(Third Embodiment) A base station can operate all of WUSBs of different sizes. In this case, each WUSB may be transmitted through different time and / or frequency resources. Configuration information for each WUSB may be directed to the wireless device through a higher layer signal such as SIB. In this case, the wireless device may be configured to monitor the WUSO in which the corresponding WUS is set by selecting a WUSB suitable for the wireless device. This may be aimed at reducing power consumption of the wireless device while supporting various coverages in a situation where the base station does not know the channel state of the wireless device.

VI-3: Third Plan of the Sixth Disclosure: Amount of Information Represented by WUS

This section describes how a base station sets the amount of information that can be represented via WUS. For example, when the WUS is transmitted in the form of a sequence, the amount of information that can be represented through the WUS may be determined by the number of sequences operated by the base station. In this case, the wireless device may estimate the WUS to be monitored according to the number of sequences set by the base station. For another example, when the WUS is transmitted in the form of DCI, the amount of information that can be expressed through the WUS may be the number of bits representing meaningful information in the DCI. In this case, the wireless device may perform blind decoding according to the bit size set by the base station, or recognize the meaningless information as a predetermined fixed value and perform decoding. The amount of information that can be represented through the WUS can be determined by one of the following embodiments. In the following description, the number of sequences is shown as an example. However, it is obvious that the number of sequences can be generally applied to other methods that can determine the amount of information that can be represented through the WUS, such as the number of bits of the DCI.

(First Embodiment) The number of sequences used for the WUS may be determined as a function of a higher layer parameter that sets the repetition size of the WUSB (or paging) or the repetition size of the WUSB (or paging). As a characteristic example, in the case of NB-IoT, the size of the WUSB may be determined as a function of R _max set for paging.

(Second Embodiment) The number of sequences used for the WUS may be determined through higher layer parameters set for the number of sequences used for the WUS. For example, the corresponding information may be transmitted through a signal such as an SIB that can be acquired by a wireless device in an RRC IDLE state.

(Third Embodiment) The number of sequences used for the WUS may be determined by the size of a group of wireless devices monitoring the same WUSO. For example, the number of sequences may be determined based on higher layer parameters used when determining the identifier (eg, UE_ID) of the wireless device.

VII. 7th disclosure: specific implementation example

Content described in the first to sixth disclosure of the present specification may be implemented as follows. In the following, for convenience of description, embodiments for informing whether or not to transmit a specific downlink channel to the wireless devices in the RRC idle state in the NB-IoT system has been described, the following description is another system designed for data transmission and reception It can also be applied to wireless devices in RRC connected mode.

The proposed content may be used for the purpose of indicating whether the wireless device should monitor POs of a specific location based on DCI. Hereinafter, the DCI used for this purpose will be described as a new DCI for convenience. The new DCI may be configured to be detected in the same search space as the NPDCCH for paging. This means that a new DCI can be transmitted in the PO. Accordingly, the wireless device may blind decode both the NPDCCH for the new DCI and the NPDCCH for the paging in the search space to be monitored according to its DRX. In this case, the new DCI may be determined to have a format of the same size as the NPDCCH for paging. This means that the number of bits represented by the new DCI is the same as the number of bits represented by the DCI for paging. This may be for the purpose of reducing the number of blind decoding required for the wireless device to detect two DCIs. In this case, the new DCI may be masked with a CRC having an independent RNTI to be distinguished from the DCI for paging. This may be for distinguishing two DCIs having the same format size in the same search space.

The new DCI may include information on a specific wireless device or a specific group of wireless devices. This information may be for identifying a wireless device to receive the new DCI among wireless devices monitoring the PO. If the wireless device confirms its identifier or an identifier of a group to which the wireless device belongs through the information of the new DCI, the wireless device may monitor the PO generated for a certain period of time. If the wireless device fails to check its identifier ID or the identifier for the group to which it belongs, the wireless device may continuously monitor the next PO.

The new DCI may include information specifying whether to monitor one or more POs. At the location of the PO determined to perform monitoring via the new DCI, the wireless device may need to perform a wake up operation. And, for the PO determined not to monitor through the new DCI, the wireless device may need to perform a go to sleep operation. In this case, the information may be expressed in the form of a bitmap, and may indicate whether the wireless device should monitor N consecutive POs after the PO where the new DCI is detected.

The new DCI may be specifically transmitted according to one of the following options.

(Option 1) The base station transmits the new DCI after determining a required time point among the transmittable POs.

(Option 2) In the transmittable PO, the new DCI is transmitted at a predetermined period from a predetermined start position.

(Option 3) In the transmittable PO, the new DCI is transmitted in an occurrence period indicated by a bitmap.

In case of option 1, scheduling flexibility is increased in that the base station can transmit only when it determines that the new DCI is needed. In the case of Option 2 and Option 3, the base station determines the corresponding location and informs the wireless device of the location through higher layer signals such as SIB or RRC signals. However, this increases the signaling overhead. In this case, even when the PO is determined to transmit the new DCI, the base station may not transmit the new DCI. This may be because the new DCI is not needed at the corresponding location, or the corresponding PO should be used for NPDCCH transmission for paging. In addition, in a section in which the wireless device does not monitor the PO for a long time such as eDRX, the wireless device may not monitor the new DCI even if the location is capable of transmitting the new DCI as specified through the option 2 and option 3 scheme. have. This may be for the purpose of reducing unnecessary power consumption of the wireless device.

Whether the new DCI is used may be indicated through higher layer signals such as SIB or RRC signaling.

If the wireless device already recognizes whether to monitor the PO through the first new DCI and monitors the PO indicated by the first new DCI, the wireless device continues whether or not the second new DCI exists. Can be monitored. In this case, the PO for monitoring the second new DCI may be determined to target only the PO indicated by the first new DCI. If the wireless device detects its identifier or the second new DCI for the group to which it belongs, the wireless device discards the information on the first new DCI previously received and monitors according to the second new DCI. PO can be determined.

If the information on the new DCI has not been received or if all of the PO sections designated by the new DCI have ended, the wireless device can monitor the PO in all possible sections. This means that the location of the existing monitoring PO is applied the same as the existing rules. (The rule used here is to determine the PO that is monitored by a wireless device that does not have the ability to distinguish a new DCI.)

VIII. 8th opening

As described above, the WUS may be used by the base station to inform a specific wireless device or a group of wireless devices that a corresponding PDCCH (or MPDCCH, or NPDCCH) will be transmitted.

As another example, the WUS may be used to inform a specific wireless device or a group of wireless devices that a PDCCH (or MPDCCH, or NPDCCH) will not be transmitted.

Similarly, the WUS may be used for indicating whether there is a PDSCH (or NPDSCH) that the wireless device expects. For example, in the case of PDSCH (or NPDSCH) transmission that does not require separate DL grant information, the WUS may be used for the purpose of indicating whether the PDSCH is transmitted while restricting the BD of the wireless device.

For another example, the WUS may be used for the purpose of confirming whether the wireless device updates specific information. Specifically, in the case of a transport channel for transmitting system information such as PBCH (or NPBCH) or SIB1 (or SIB1-BR, SIB1-NB), it may be used for notifying whether the corresponding information is updated.

Alternatively, the WUS may be used for the purpose of the wireless device skipping specific NPDCCH monitoring and performing downlink reception or uplink transmission according to preset information. In this case, the configuration information used may be previously specified through higher layer signals such as SIB or RRC signals.

Or it may be used for the purpose of presenting the information of the previously received DCI as it is. In this case, if the wireless device applies the same type of DL grant when receiving a continuous downlink channel, the wireless device that detects the corresponding WUS can skip monitoring of the associated NPDCCH. If the wireless device applies the same type of UL grant when transmitting a continuous uplink channel, the wireless device that detects the corresponding WUS may skip monitoring of the associated NPDCCH.

This section describes the case where WUS is used as an example for the purpose of informing whether or not to monitor the NPDCCH for convenience of explanation, but it is obvious that the present invention can also be generally applied to other purposes such as the above example. .

VIII-1. First Scheme of the Eighth Disclosure: A Physical Signal-Based WUS Design

This section considers the case where WUS is generated in sequence form and proposes possible design methods.

The WUS may be generated in a form based on a ZCoff (Zadoff-Chu) sequence and a bit sequence. At this time, the WUS may be expressed by the following equation.

N is a value representing an index of the sequence, and has a value between 0 and N-1 when the length of the sequence is N. The length N of the sequence may be determined by the unit of the RE group in which one WUS is represented. For example, the value of N may be determined according to the size of the OFDM symbol used. If the WUS sequence is represented through n _sym symbols and the number of subcarriers included in one symbol is n _subcarriers , the length N of the WUS sequence may be expressed as follows.

As a characteristic example, the size of n _subcarriers in NB-IoT may be 12.

In Equation 8, the size of N _ZC may be determined as a prime number close to N. If the size of N is determined by the number of OFDM symbols used in one WUS sequence, the size of N _ZC may also be a function form determined by the number of OFDM symbols used. Characteristic For example, in the case of NB according to Equation 9 and n _subcarrier = 12 in NB-IoT, the size of N _ZC determined by the number of symbols constituting one WUS is selected from the values specified in the table below. Can be used.

n _sym N N _ZC One 12 11, 13 2 24 23 3 36 37 4 48 47 5 60 59, 61 6 72 71,73 7 84 83 8 96 97 9 108 107, 109 10 120 113, 127 11 132 131 12 144 139,149 13 156 157 14 168 167

For example, the N _ZC = 13 without the use of N _ZC = 11 can be used for the case of n = 1 _sym prevent performance degradation of NPSS. In addition, in the NB-IoT, when the WUS reuses the NSSS sequence, it may be selected to have values of n _sym = 11, N = 132, and N _ZC = 131, and in NB-IoT, the number of symbols that can be used for each operation mode. Since N _ZC may be determined according to an operation mode, b _q (n), θ _r and u _s may be used to distinguish information. The information expressed at this time may be a wireless device ID (or group ID of a wireless device), a cell ID, an NPDCCH interval to be monitored, time / frequency resource allocation, a new data indication (NDI), a system information indication indication, and a wake up. Or sleeping. b _q (n), θ _f , and u _s may each be used independently or in combination of one or more methods. When more than one method is used in combination, each variable may express separate information or may be used for the purpose of dividing one piece of information. If the information represented includes the ID of the wireless device (or group ID of the wireless devices), the at least one sequence is intended to wake up (or go to sleep) all the wireless devices that monitor the sequence position. Can be used. This may be the case where wake up should be performed for all wireless devices such as system information update, or the purpose is to wake up (or go to sleep) a group of two or more wireless devices. Alternatively, a sequence for informing update of system information may be used separately. This may be for obtaining a benefit of reducing power consumption and delay by acquiring update information using only the WUS without performing an additional operation of monitoring a paging message for a wireless device that can read the WUS when the system information update is determined. have.

b _q (n) may be in the form of a sequence having a value of 1 or -1. At this time, the sequence used may be selected to select some of the rows of the Hadamard matrix. The size of the Hadamard matrix used at this time can be determined to have a value equal to the length N of the WUS sequence. For example, if WUS follows the form of NSSS and is designed to distinguish four pieces of information through b _q (n), b ₀ (n), b ₁ (n), b ₂ (n), and b ₃ (n) can be chosen to select the 1, 32, 64, and 128th rows of a 128x128 Hadamard mattress, respectively. If the WUS follows the NSSS form and is designed to distinguish eight pieces of information through b _q (n), the 1st, 16th, 32th, 48th, 64th, 80th, 112th, and 128th of the 128x128 Hadamard matrix You can use rows. Alternatively, a pseudo-random sequence sequence may be used for b _q (n). For example, the pseudo-random sequence used may be a length-31 Gold sequence defined and used in the LTE standard TS 36.211, as shown in Equation 11. In this case, the distinguished information is determined by initialization of x ₂ (n), and may be expressed as in the following equation.

For example, if the WUS is designed to distinguish eight pieces of information, C _init can have eight different integer values.

The length of b _q (n) may be determined to have a value equal to the length N of the WUS sequence. In this case, the length of N may be determined to include all REs in a symbol in which WUS is used without considering the number of REs that are punctured or overlapped for transmission of the reference signal RS. Alternatively, the length of b _q (n) may be determined based on the actual number of REs used in the WUS. For example, if the total number of REs used for WUS in the NB-IoT is 100, the length of the PN-sequence may also be determined to satisfy 100. As in this example, when the length of the WUS sequence is determined by the number of REs used in the WUS, when the number of REs available in the WUS varies depending on the operation mode, the length of the PN-sequence may be determined according to the operation mode. have.

θ _r can be expressed in the form of the following equation. In the following equation, R denotes the size of information represented by θ _r and r denotes the index of the information. For example, when θ _r is used to classify four pieces of information, it has a value of R = 4, and r may be selected to select one of 0, 1, 2, and 3 values.

u _s is a value that determines the root sequence index of the ZC sequence and may be expressed as any integer. When N _ZC is determined in Equation 8, the number of integers that can be used as the value of u _s may be N _ZC in total. In this case, when the size of information to be classified into WUS is S, a total of S integers among N _ZC integers may be selected and used for the purpose of WUS. In this case, the S root sequence indexes to be selected may be selected in order of minimizing PAPR (or CM) of the ZC sequence. In addition, the selected S root sequence indexes may be selected so as not to affect or minimize sequence performance for other purposes. For example, if n _sym = 1 and N _ZC = 11 is used, then u _s selected for WUS can be chosen to be selected except five. This may be aimed at preventing deterioration of cell selection / reselection performance and WUS performance by distinguishing from NPSS. For example, if one root sequence index is selected for the purpose of WUS, we can decide to use u _s = 6.

The method of mapping the WUS to the resource may be based on a frequency first and time second method. In this case, RE element positions used for all reference signal purposes may be determined to be punctured. For example, in the case of NB-IoT, the REs used for the CRS and the NRS may be determined such that the WUS is punctured. This means that if the WUS decides to use the NB-IoT downlink subframe, the wireless devices can expect the NRS to be transmitted in that subframe, and the previous compatibility for wireless devices that do not have the ability to recognize the WUS supporting structure. backward compatibility).

In a structure in which a WUS is a resource mapping, when a single WUS or a repeated WUS uses consecutive symbols, a cover code of a time unit made of one or more symbols may be applied. have. In this case, the time unit used may be one symbol, slot, or subframe, or may be the number of symbols required for resource mapping of one WUS. This may be for distinguishing from signals of other purposes having a structure similar or identical to the designed WUS. For example, when a WUS having a structure similar to NPSS is used in NB-IoT, a cover code having an orthogonal or low correlation property with a symbol unit cover code used in NPSS is used for WUS. Can be used as Alternatively, a cover code of a time unit may be used for the purpose of representing information. For example, a plurality of cover codes that are orthogonal to each other or satisfy low correlation components may be used for the purpose of representing information transmitted through the WUS.

If the wake up operation and the go to sleep operation are classified into a sequence type, the wireless device may determine to monitor the associated NPDCCH only when a sequence corresponding to the wake up is transmitted. In this case, when a sequence corresponding to the operation of go to sleep is transmitted, the signal may be used for the purpose of skipping one or more NPDCCH search spaces. If the purpose is to skip one NPDCCH, an operation not transmitting a signal may be performed. In this case, the wireless device may determine a subsequent operation according to the presence or absence of the detected signal and the type of sequence applied in the case of the detection. The above operation may be represented by the following example.

When the wake up sequence is transmitted: The wireless device performs an operation of monitoring one NPDCCH (or NPDSCH) indicated by the detected signal.

If no signal is transmitted: The wireless device skips without monitoring one NPDCCH (or NPDSCH) associated with the signal occurrence that attempted detection.

When a Go to sleep sequence is transmitted: The wireless device performs a skip operation without monitoring a plurality of NPDCCHs (or NPDSCHs) indicated by the detected signals or NPDCCHs (or NPDSCHs) for a predetermined period of time.

VIII-2. Second Scheme of the Eighth Disclosure: A Physical Channel-Based WUS Design Scheme

This section proposes methods that WUS generates in the form of physical channels. When the WUS is generated in the form of a physical channel, the form may be a channel including a DCI such as PDCCH (or MPDCCH, NPDCCH). In this case, the information included in the DCI includes a wireless device ID (or group ID of wireless devices), a cell ID, an NPDCCH interval to be monitored, time / frequency resource allocation, a new data indication (NDI), a system information update indication, and a wake up or sleeping It can be whether or not. The listed information may be expressed by combining one or more information in the DCI for one WUS.

If the information for notifying the system information update is included, the 1-bit flag indicating whether the WUS is for wake up (or go to sleep) or for notifying the system information update may be used in the DCI. For example, information of 1 may specify operation of wake up (or go to sleep), and information of 0 may specify operation of system information update. In this case, the information included in the DCI may be different depending on the information of the flag. For example, if a flag indicating a system information update is included, the remaining bits of the DCI may be used for the purpose of indicating information related to the system information update.

If information indicating whether to wake up or sleeping is included, the corresponding information may be expressed using 1 bit in DCI. For example, information of 1 may indicate a wake up operation and information of 0 may indicate go to sleep. If the corresponding bit plays the same role as the flag, the information represented by the remaining bits may vary depending on the bit represented by the flag. For example, the number of bits for determining a group of wireless devices or an NPDCCH monitoring interval may be defined differently according to a corresponding flag. Alternatively, CRC masking may be used to express information indicating whether to wake up or sleeping. For example, two RNTIs can be specified to refer to wake up and sleeping, respectively. In this case, the DCI representing the wake up information and the DCI representing the go to sleep information may be determined to be equal to each other, and the information represented by the bits of each DCI may be different from each other. If a flag indicating a system information update exists, a flag indicating wake up or go to sleep may be selectively checked after reading a flag indicating a system information update. This is because if the WUS is used for notifying the system information update, the wireless device that detects the WUS does not need to select wake up or go to sleep, and the content of the DCI is also changed.

If information on the ID of the wireless device (or group ID of the wireless devices) is included, the number of DCI bits may be the same as the number of IDs (or group IDs of the wireless devices) to be distinguished. At this time, for example, the bit 1 information may be determined not to perform the wake up (or go to sleep) operation, and the 0 information may not be performed to the wake up (or go to sleep) operation. For example, if a wireless device for monitoring the corresponding WUS is divided into L groups to inform whether wake up (or go to sleep) is operating, the number of bits for indicating a group of wireless devices may be a total of L. have. In this case, one or more groups of wireless devices that are designated with information of 1 to perform an operation among the L groups may be one or more. The value of the size L of the distinguished group may be specified through higher layer signals such as SIB or RRC signals. In this case, if the maximum usable size of L is L _max , the size of L indicated through a higher layer signal may be a value between 1 and L _max . If the size of L is smaller than L _max , L _max -L bits can be used for other purposes or represented as a fixed value. If a flag indicating whether to wake up or go to sleep is used, the size of L _max and / or L may vary depending on the information represented by the flag.

If the information included in the DCI designates a section for monitoring the NPDCCH, the corresponding information may be defined as a time at which a wake up (or go to sleep) command is applied. In this case, the size of the interval to be monitored may be determined in advance so that each combination representing bits used for the corresponding purpose in the DCI indicates a specific interval. When M bits are used for expressing corresponding information in each DCI, the size of the monitoring interval that can be expressed may be 2 ^M in total. In this case, the size of M may be specified through a higher layer signal such as an SIB or RRC signal. At this time, if the maximum usable size of M is M _max , the size of M indicated through a higher layer signal may be a value between 1 and M _max . If the size of M is smaller than M _max , M _max -M bits can be used for other purposes or represented as a fixed value. If a flag indicating whether to wake up or go to sleep is used, the size of M _max and / or M may vary depending on the information expressed by the flag. In addition, the information represented by the combination of bits used and the size of the interval for monitoring the NPDCCH corresponding thereto may vary depending on the information represented by the flag.

If the information included in the DCI coordinates the DRX cycle, the information may be for performing dynamic DRX control for each wireless device or group of wireless devices. If P bits are used for adjusting DRX cycles, 2 ^P DRX cycle operations are possible. For example, Table 3 below shows an example of determining the constant used to adjust the DRX cycle when two bits are used for adjusting the DRX cycle. In the following table, c _DRX value is a constant that adjusts the DRX cycle, and when DRX value acquired through upper layer parameter is T _DRX , the newly applied DRX value T _{DRX_new} can be _determined by the relationship of T _{DRX_new} = c _DRX * T _DRX . have.

Bit pattern c _DRX 00 One 01 2 10 4 11 8

When WUS using DCI is used in NB-IoT, an N-bit payload may be added and encoded in addition to the DCI bit. For example, CRC may be used as the payload added at this time. Specifically, an 8-bit CRC may be used in the NB-IoT. The purpose of the present invention may be to reduce the number of bits required to configure the WUS in order to reduce power consumption for the WUS as compared with the NPDCCH to which the WUS exists. In this case, the RNTI value may be used for CRC masking to inform that the corresponding DCI is the purpose of the WUS. Alternatively, the WUS may be determined based on an arbitrary bit pattern associated with a cell ID or configured from a base station for the purpose of identifying a cell to which a WUS is transmitted. As another example, the added load may use RNTI or bit information (for example, a value calculated based on a cell ID or an arbitrary bit pattern set from a base station) used for distinguishing cells. This may be for the purpose of delivering information to a wireless device or a group of wireless devices that need the WUS instead of using an unnecessary length of CRC to prevent an increase in overall overhead when the DCI is short. When the .WUS is generated in the form of a physical channel, the DCI size of the WUS may be determined to have the same size as the NPDCCH to which the WUS exists. At this time, the target NPDCCH and the physical channel for WUS can be distinguished through RNTI. In addition, the occurrence interval in which the WUS is monitored may be determined to share the same location as the NPDCCH to which the WUS exists. The advantages of using this approach are: (1) reusing existing search spaces without adding a separate search space for WUS, and (2) introducing new physical channels without increasing blind decoding (BD). (3) Even if the wireless device misses the WUS, it can induce an operation to monitor the next search space. For example, when the technique is used to specify a go to sleep operation for a specific wireless device or a group of wireless devices, the index of the wireless device group and the section in which the go to sleep proceeds are specified in DCI information. It can be used, which can be used for the purpose of supporting dynamic DRX setup. For example, WUS's DCI can indicate only those search spaces that wireless devices need to monitor in the future, or only those search spaces that do not need to be monitored. According to this, power consumption can be reduced compared to the existing wireless device has to monitor all the search space. In addition, the DCI of the WUS may indicate a DRX change. If you change the DRX cycle to increase through the DCI of WUS, power consumption may be reduced. VIII-3. Third Scheme of the Eighth Disclosure: Two Steps of WUS

This section describes how to support two levels of wake up (or go to sleep) by combining physical signals and physical channels.

In a two-step wake up (or go to sleep) procedure, the physical channel may be used for the purpose of indicating whether there is information related to wake up (or go to sleep). If the wireless device detects a physical signal corresponding to itself, the next step may be to monitor the physical channel associated with the WUS. In this case, the physical signal may use the contents of the scheme and information described in the first scheme of the eighth time. In this case, information transmitted through the physical signal may be minimized in order to reduce power consumption or delay occurring in the process of monitoring the physical signal and to increase accuracy. For example, the information may indicate whether the physical channel is transmitted. Only 1 bit indication information may be used. In addition, the information expressed through the corresponding physical signal may include information for distinguishing operations of wake up and go to sleep. In this case, if more than one sequence is used for the physical signal, each sequence may be divided and used for the purpose of expressing a group of wireless devices or a cell ID.

In the two-step wake up (or go to sleep) procedure, the physical channel may be used for the purpose of informing detailed information related to wake up (or go to sleep). For example, the generation of the corresponding physical channel may use the methods mentioned in the second scheme of the eighth disclosure.

Alternatively, a combination of two levels of wake up (or go to sleep) may be configured by a combination of two physical signals. For example, the first physical signal may be for providing downlink time synchronization, and the second physical signal may be for transmitting information. For example, the first physical signal may be a modified form of PSS (or NPSS), and the second physical signal may be a modified form of SSS (or NSSS).

The first physical signal can be determined to always transmit without providing information. This may be for the purpose of always supporting the operation of downlink synchronization even if there is no indication of the actual wake up operation.

Alternatively, the first physical signal may provide information of wake up or go to sleep. If there is a signal, it informs wake up and informs go to sleep using the DTX method, or distinguishes wake up and go to sleep by using a different sequence configuration method.

The first physical signal may be represented by a sequence distinguished by cell ID. This may be for the purpose of preventing malfunction due to a physical signal transmitted from an adjacent cell.

The information provided by the second physical signal may be information about a cell ID, a wireless device (or group) ID, and / or an NPDCCH generation interval. The information on the NPDCCH monitoring interval may be information such as a location, number, or period in which the NPDCCH is set.

The two physical signals constituting the two levels of wake up (or go to sleep) may each be enabled / disabled separately. For example, whether the operation is performed through the 1-bit indication may be determined through higher layer signals such as SIB or RRC signals. The terminal may determine the downlink time synchronization acquisition method and the type and amount of information received through the physical signal based on the information of the physical signal received from the base station.

VIII-4. Fourth Scheme of Eighth Initiation: Subframe Index Acquisition

When a physical signal capable of acquiring downlink time synchronization is used, if a time drift occurs for 1 ms or more, the subframe index estimated by the UE and the actual subframe index may be different from each other. In order to prevent this, the information on the subframe index or the position where the physical signal starts and ends may be provided using the pattern of the cover code. In this case, the cover code may be applied in a unit in which a physical signal is repeated. For example, when a physical signal of a subframe unit is applied, the cover code may be applied at the subframe level. This may be aimed at lowering the detection complexity of the physical signal and maintaining the characteristics of the sequence.

The cover code applied may be specified to be initialized, from the start subframe of the physical signal. Alternatively, the cover code may be generated by a random number generated from the subframe index.

In the illustrative description above, the approaches are described in a series of steps or blocks, but the disclosure herein is not limited to the order of these steps, and certain steps may occur in a different order or concurrently with other steps than those described above. Can be. In addition, those skilled in the art will appreciate that the steps shown in the flowcharts are not exclusive and that other steps may be included or one or more steps in the flowcharts may be deleted without affecting the scope of the present invention.

Embodiments of the present invention described so far may be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof. Specifically, it will be described with reference to the drawings.

19 is a block diagram illustrating a wireless device and a base station in which the present disclosure is implemented.

Referring to FIG. 19, the wireless device 100 and the base station 200 may implement the disclosure herein.

The illustrated wireless device 100 includes a processor 101, a memory 102, and a transceiver 103. The base station 200 shown likewise includes a processor 201, a memory 202, and a transceiver 203. The illustrated processor 101, 201, memory 102, 202, and transceiver 103, 203 may be implemented as separate chips, or at least two blocks / functions may be implemented through one chip.

The transceivers 103 and 203 include a transmitter and a receiver. When a specific operation is performed, only one of the transmitter and the receiver may be performed, or both the transmitter and the receiver may be performed. The transceivers 103 and 203 may include one or more antennas for transmitting and / or receiving wireless signals. In addition, the transceivers 103 and 203 may include amplifiers for amplifying received and / or transmitted signals and bandpass filters for transmission over a particular frequency band.

The processors 101 and 201 may implement the functions, processes, and / or methods proposed herein. The processors 101 and 201 may include an encoder and a decoder. For example, the processors 101 and 202 may perform operations according to the above description. Such processors 101 and 201 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters that convert baseband signals and wireless signals to and from each other.

The memories 102 and 202 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage devices.

20 is a detailed block diagram of a transceiver of the wireless device shown in FIG. 19.

Referring to FIG. 20, the transceiver 110 includes a transmitter 111 and a receiver 112. The transmitter 111 includes a discrete fourier transform (DFT) unit 1111, a subcarrier mapper 1112, an IFFT unit 1113, a CP insertion unit 1144, and a wireless transmitter 1115. The transmitter 111 may further include a modulator. Further, for example, the apparatus may further include a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown) and a layer permutator (not shown). It may be disposed before the DFT unit 1111. That is, in order to prevent an increase in peak-to-average power ratio (PAPR), the transmitter 111 first passes the information through the DFT 1111 before mapping a signal to a subcarrier. After subcarrier mapping of the signal spread (or precoded in the same sense) by the DFT unit 1111 through the subcarrier mapper 1112, the inverse fast fourier transform (IFFT) unit 1113 is passed on the time axis. Make it a signal.

The DFT unit 1111 outputs complex-valued symbols by performing a DFT on the input symbols. For example, when Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit 1111 may be called a transform precoder. The subcarrier mapper 1112 maps the complex symbols to each subcarrier in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper 1112 may be called a resource element mapper. The IFFT unit 1113 performs an IFFT on the input symbol and outputs a baseband signal for data, which is a time domain signal. The CP inserter 1114 copies a part of the rear part of the base band signal for data and inserts it in the front part of the base band signal for data. Inter-symbol interference (ISI) and inter-carrier interference (ICI) can be prevented through CP insertion to maintain orthogonality even in multipath channels.

On the other hand, the receiver 112 includes a wireless receiver 1121, a CP remover 1122, an FFT unit 1123, an equalizer 1124, and the like. The radio receiver 1121, the CP remover 1122, and the FFT unit 1123 of the receiver 112 include a radio transmitter 1115, a CP insertion unit 1114, and an IFF unit 1113 at the transmitter 111. Performs the reverse function of The receiver 112 may further include a demodulator.

Claims (15)

A method for a wireless device to receive a paging message, Determining a wake up signal occasion (WUSO) window to attempt to receive a wake up signal (WUS); Monitoring the downlink control channel during a paging window to attempt to receive the paging message when the WUS is received within the determined WUSO window, Wherein the WUSO window is determined by the size and offset of the interval. The method of claim 1, A plurality of paging windows or PO (paging occasion) is instructed by the WUS, The PO indicates a subframe in which transmission of the paging message starts in the paging window. The method of claim 1, And defining a time interval in which the WUS exists within the determined WUSO window as WUSO. The method of claim 2, And the offset indicates a difference from the PO to a start point or an end point of the WUSO window. 4. The method of claim 3, wherein if the subframe in which the WUSO is present is an invalid subframe, the WUSO is deferred to a subsequent valid subframe. The method of claim 3, wherein the frequency resource region in which the WUSO window exists is the same as the frequency resource region in which the PO exists. 4. The method of claim 3, wherein the WUSO overlaps some or all of the search space of another downlink control channel with time resources, or if the WUSO overlaps some or all of other channels with time resources. Attempt to receive a WUS is abandoned. 8. The method of claim 7, wherein if the WUS attempt to receive is abandoned, the reception of the paging message is monitored during the PO corresponding to the WUSO, regardless of whether the WUSO is transmitted. The method of claim 1, wherein the WUS includes an identifier of a wireless device or a group identifier of wireless devices to receive the paging message. The method of claim 1, The block used by the WUS is defined as a wake up signal block (WUSB), And the repetition size of the WUSB is determined based on an upper layer parameter set for the WUS and an upper layer parameter set for the paging message. The method of claim 1, The WUS is generated based on any one of a plurality of sequences, And an identifier of a wireless device or a group identifier of wireless devices is used to generate the sequence. The method of claim 11, At least one of the plurality of sequences is used to wake or sleep all wireless devices. A wireless device that receives a paging message, A transceiver; And A processor for controlling the transceiver; The processor determines a wake up signal occasion (WUSO) window to attempt to receive a wake up signal (WUS), When the WUS is received within the determined WUSO window, the processor controls the transceiver to monitor the downlink control channel during the paging window to attempt to receive the paging message. Wherein the WUSO window is determined by the size and offset of the interval. The method of claim 13, A plurality of paging windows or PO (paging occasion) is instructed by the WUS, Wherein the PO indicates a subframe in which transmission of the paging message starts in the paging window. The method of claim 14, And a time interval in which the WUS exists in the determined WUSO window is defined as WUSO.

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