KR102596431B1 - Method and apparatus for transmission and reception of signal in wireless communication system - Google Patents

Abstract

A method for a terminal to transmit and receive a signal in a wireless communication system according to an embodiment of the disclosure includes receiving a logical channel release instruction from a base station, and based on the logical channel release instruction, a logical channel to be released, and a logical channel to be released. It determines the operation mode and whether to re-establish the connected PDCP (Packet Data Convergence Protocol) layer device, and based on the determination result, a PDCP data recovery procedure can be performed.

Description

Method and device for transmitting and receiving signals in a wireless communication system {METHOD AND APPARATUS FOR TRANSMISSION AND RECEPTION OF SIGNAL IN WIRELESS COMMUNICATION SYSTEM}

The disclosed embodiments relate to a wireless communication system, and more specifically, to a method and device for transmitting and receiving signals in a wireless communication system.

In order to meet the increasing demand for wireless data traffic following the commercialization of the 4G communication system, efforts are being made to develop an improved 5G communication system or pre-5G communication system. For this reason, the 5G communication system or pre-5G communication system is called a Beyond 4G Network communication system or a Post LTE system. To achieve high data rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (such as the 60 GHz band). In order to alleviate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, the 5G communication system uses beamforming, massive array multiple input/output (massive MIMO), and full dimension multiple input/output (FD-MIMO). ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, to improve the network of the system, the 5G communication system uses advanced small cells, advanced small cells, cloud radio access networks (cloud RAN), and ultra-dense networks. , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation. Technology development is underway. In addition, the 5G system uses FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), which are advanced coding modulation (ACM) methods, and advanced access technologies such as FBMC (Filter Bank Multi Carrier) and NOMA. (non orthogonal multiple access), and SCMA (sparse code multiple access) are being developed.

Meanwhile, the Internet is evolving from a human-centered network where humans create and consume information to an IoT (Internet of Things) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection to cloud servers, etc., is also emerging. In order to implement IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, sensor networks for connection between things, and machine to machine communication (Machine to Machine) are required to implement IoT. , M2M), and MTC (Machine Type Communication) technologies are being researched. In an IoT environment, intelligent IT (Internet Technology) services that create new value in human life can be provided by collecting and analyzing data generated from connected objects. IoT is used in fields such as smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliances, and advanced medical services through the convergence and combination of existing IT (information technology) technology and various industries. It can be applied to .

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, Machine to Machine (M2M), and Machine Type Communication (MTC) are implemented through 5G communication technologies such as beam forming, MIMO, and array antennas. There is. The application of cloud radio access network (cloud RAN) as the big data processing technology described above can be said to be an example of the convergence of 5G technology and IoT technology.

As one of many technologies to meet the growing demand for high-capacity communication, a method of providing multiple connections has been proposed. For example, the carrier aggregation (CA) technique of the Long Term Revolution (LTE) system can provide multiple connections through multiple carriers. Accordingly, users can receive services through more resources. Additionally, various services, including broadcasting services such as MBMS, can be provided through the LTE system.

In a wireless communication system, service area inconsistencies may occur in the uplink and downlink. When a discrepancy occurs, there is a concern that the quality of service may deteriorate, and by placing restrictions on the uplink or downlink service area, problems may arise in which the service area cannot be used efficiently.

Additionally, in a wireless communication system, dual access technology can be used to transmit more data at high speed in the downlink and uplink, and redundant transmission can be performed using dual access technology to increase reliability. Dual access technology can be configured for multiple bearers. Therefore, for split bearers or SCG bearers using dual access technology, the logical channels of each split bearer or each SCG bearer are independently released and the split bearer is typed as a normal bearer (MCG bearer or SCG bearer). A procedure is required to change or release the SCG bearer.

In addition, in the case of uplink in a wireless communication system, the terminal has a physically small size, and the uplink frequency is difficult to use high frequency bands and wide bandwidth, so uplink transmission resources are a bottleneck compared to downlink transmission resources. phenomenon may occur. Additionally, since the maximum transmission power of the terminal is less than the maximum transmission power of the base station, a problem of reduced coverage may also occur when transmitting uplink data.

A method for a terminal to transmit and receive a signal in a wireless communication system according to an embodiment includes receiving a logical channel release instruction from a base station; Based on the logical channel release instruction, determining a logical channel to be released, an operation mode of the logical channel to be released, and whether to re-establish a connected Packet Data Convergence Protocol (PDCP) layer device; and performing a PDCP data recovery procedure based on the determination result.

In the disclosed embodiment, communication performance can be improved by solving the problem of service area mismatch between uplink and downlink in a wireless communication system.

In the disclosed embodiment, the logical channels of each split bearer or each SCG bearer are independently released for split bearers or SCG bearers using dual access technology, and the split bearer is converted to a normal bearer (MCG bearer or SCG bearer). ) by proposing a procedure to change the type or release the SCG bearer, so that the type of each bearer can be freely changed, thereby reducing signaling overhead due to setting and resetting the bearer type and reducing transmission delay.

In addition, the disclosed embodiment proposes a procedure for compressing and decompressing data when a terminal transmits data on the uplink or when a base station transmits downlink to the terminal in a wireless communication system, thereby reducing overhead and allowing more It can have the effect of improving coverage while allowing data to be transmitted.

FIG. 1A is a diagram showing the structure of a next-generation mobile communication system.
FIG. 1B is a conceptual diagram illustrating a method of applying an additional uplink frequency according to an embodiment.
Figure 1c is a diagram to explain the uplink and downlink service areas in the next-generation mobile communication system.
FIG. 1D is a flowchart illustrating a method of performing cell selection by considering additional uplink frequencies in one embodiment.
FIG. 1E is a flowchart illustrating a process of performing cell selection in consideration of additional uplink frequencies according to an embodiment.
FIG. 1F is a flowchart for explaining a UE operation that performs cell selection in consideration of additional uplink frequencies in the first embodiment.
FIG. 1G is a flowchart for explaining a UE operation that performs cell selection in consideration of additional uplink frequencies in the second embodiment.
Figure 1h is a flowchart for explaining a UE operation that performs cell selection in consideration of additional uplink frequencies in the third embodiment.
FIG. 2C is a flowchart illustrating a process for setting an additional uplink frequency according to an embodiment.
FIG. 2D is a flowchart illustrating a terminal operation for setting an additional uplink frequency according to an embodiment.
FIG. 3A is a diagram illustrating the structure of an LTE system to which the disclosed embodiment can be applied.
FIG. 3B is a diagram showing a wireless protocol structure in an LTE system to which the disclosed embodiment can be applied.
FIG. 3C is a diagram showing the structure of a next-generation mobile communication system to which the disclosed embodiment can be applied.
FIG. 3D is a diagram showing the wireless protocol structure of a next-generation mobile communication system to which the disclosed embodiment can be applied. .
FIG. 3E is a diagram illustrating dual connectivity bearers or multiple connectivity bearers that can be configured for a terminal to which dual connectivity or multi-connectivity technology is applied in a next-generation mobile communication system according to an embodiment.
FIG. 3F is a diagram illustrating a procedure in which the base station sets various bearers described in FIG. 3E to the terminal as RRC messages and sends an RRC message to release the logical channel of the established bearer when the terminal establishes a connection in the disclosed embodiment.
Figure 3g is a diagram showing the operation of the terminal when it receives a logical channel release instruction from the base station according to one embodiment.
Figure 4e is a diagram illustrating a procedure for configuring whether a base station will perform uplink data compression when a terminal establishes a connection to a network according to an embodiment.
FIG. 4F is a diagram illustrating a procedure and data configuration for performing uplink data compression according to an embodiment.
Figure 4g is a diagram illustrating an example of an uplink data compression method according to an embodiment.
Figure 4h is a diagram explaining a UDC header according to one embodiment.
Figures 4i and 4j are diagrams illustrating a procedure for configuring data (PDCP PDU) by defining a new field to reduce overhead in the PDCP header and applying the new field to reduce overhead, according to an embodiment.
Figure 4k is a diagram showing the operation of a transmitting end (terminal) of a UDC processing method that reduces overhead according to an embodiment.
Figure 4l is a diagram showing the operation of a receiving end (base station) of a UDC processing method for reducing overhead according to an embodiment.
Figure 4m is a block diagram of a terminal according to one embodiment.
Figure 4n is a block diagram of a base station according to one embodiment.

In the following description of the present invention, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. The terms described below are defined in consideration of the functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.

In the following description of the present invention, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

Terms used in the following description to identify a connection node, a term referring to network entities, a term referring to messages, a term referring to an interface between network objects, and a term referring to various types of identification information. The following are examples for convenience of explanation. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having equivalent technical meaning may be used.

For convenience of description below, the present invention uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard. However, the present invention is not limited by the above terms and names, and can be equally applied to systems complying with other standards. In the present invention, eNB may be used interchangeably with gNB for convenience of explanation. That is, a base station described as an eNB may represent a gNB.

FIG. 1A is a diagram showing the structure of a next-generation mobile communication system.

Referring to Figure 1a, as shown, the radio access network of the next-generation mobile communication system (New Radio, NR) includes a next-generation base station (New Radio Node B, hereinafter gNB) (1a-10) and AMF (1a-05, New Radio). Core Network). A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (1a-15) can access an external network through gNB (1a-10) and AMF (1a-05).

In Figure 1a, gNB corresponds to eNB (Evolved Node B) of the existing LTE system. gNB is connected to the NR UE through a wireless channel and can provide superior services than the existing Node B (1a-20). In the next-generation mobile communication system, all user traffic is serviced through a shared channel, so a device that collects status information such as buffer status, available transmission power status, and channel status of UEs and performs scheduling is required, which is called gNB (gNB). 1a-10) may be in charge. One gNB can typically control multiple cells. In order to implement ultra-high-speed data transmission compared to existing LTE, it can have more than the existing maximum bandwidth, and beamforming technology can be additionally applied using Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology. . Additionally, an adaptive modulation & coding (AMC) method that determines the modulation scheme and channel coding rate according to the channel status of the terminal may be applied. AMF (1a-05) can perform functions such as mobility support, bearer setup, and QoS setup. AMF is a device that handles various control functions as well as mobility management functions for the terminal and can be connected to multiple base stations. Additionally, the next-generation mobile communication system can be linked to the existing LTE system, and AMF can be connected to the MME (1a-25) through a network interface. The MME can be connected to an existing base station, eNB (1a-30). A terminal that supports LTE-NR Dual Connectivity can transmit and receive data while maintaining connectivity to not only the gNB but also the eNB (1a-35).

FIG. 1B is a conceptual diagram illustrating a method of applying an additional uplink frequency according to an embodiment.

In mobile communication systems, service area inconsistencies may occur in the uplink and downlink. Here, the discrepancy may occur due to different channel characteristics of the uplink and downlink, limitations in the maximum transmission power of the terminal, or structural limitations in the transmission antenna. Typically, the downlink service area may be wider than the uplink service area. For example, in a 3.5 GHz TDD system, the downlink service area (1b-05) is wider than the uplink service area (1b-10). In this case, the first terminal (1b-20) has no problem receiving services in the uplink and downlink, but the second terminal (1b-25) successfully transmits data to the base station (1b-15) in the uplink. Problems may arise. Therefore, in order to eliminate problems caused by inconsistency, the effective service area of the downlink can be reduced to match the uplink. In other words, although a wider service area can be provided in the downlink, the downlink service area is limited to correspond to the uplink service area to reduce problems caused by service area inconsistency.

In the next generation mobile communication system, in order to solve performance limitations due to mismatch, the terminal can apply an uplink frequency with a wider service area. For example, a 3.5 GHz uplink and a separate 1.8 GHz uplink (1b-30) can be additionally provided to the terminal. Additional uplink frequencies are called supplementary uplink (SUL) frequencies. Due to frequency characteristics, the lower the frequency band, the longer the wireless signal propagation distance. Therefore, 1.8 GHz, which is lower than 3.5 GHz, can provide a wider service area. Accordingly, the second terminal (1b-50) can successfully transmit data to the base station (1b-40) using the 1.8 GHz uplink (1b-35).

In addition, the first terminal (1b-45) has nothing to do with the service area problem, but can use both 1.8 GHz and 3.5 GHz uplinks, so for the purpose of distributing uplink access congestion, one of 1.8 GHz and 3.5 GHz You can also select and use. At this time, the additional uplink frequency may be an LTE frequency.

Both the NR uplink frequency and the SUL frequency can be set for one terminal, and PUSCH, an uplink data channel, can be transmitted only on one uplink at a time. PUCCH is also transmitted only on one uplink at a time, and may be transmitted on the same or different uplink as PUSCH.

A base station supporting SUL can provide the first threshold required to determine the uplink to attempt random access to the terminals in the cell using system information. A terminal supporting SUL can measure the SSB (Sync Signal Block) broadcasted by the base station in the downlink, derive RSRP, and compare RSRP with the first threshold. If the measured downlink channel quality is lower than the first threshold, the terminal may select the SUL frequency as the uplink to attempt random access. If the measured downlink channel quality is not lower than the first threshold, the terminal can perform random access at the NR uplink frequency.

Figure 1c is a diagram to explain the uplink and downlink service areas in the next-generation mobile communication system.

The phenomenon of mismatch of service areas in uplink and downlink that can occur in mobile communication systems has been described above. This problem of service area inconsistency may also affect cell selection. In a mobile communication system, cell selection refers to an operation in which a terminal in standby mode selects a cell to camp on. The terminal can determine this by determining whether the S-Criteria formula is satisfied. The terminal monitors paging messages from the selected cell and can perform random access to the selected cell. For example, since the first terminal (1c-10) is located in the uplink and downlink service areas, there is no problem at all in selecting a cell. However, while the second terminal (1c-15) is located within the downlink service area (1c-20), it may be located outside the uplink service area (1c-25). This may mean that even if the second terminal uses its maximum transmission power, its signal does not reach the base station (1c-05). As S-Criteria to be applied in the next-generation mobile communication system, S-Criteria in conventional LTE technology can be considered. S-Criteria in conventional LTE technology are as follows. At this time, the second terminal does not satisfy the S-Criteria and cannot select the cell.

[Formula 1]

Srxlev > 0 AND Squal > 0

where:

Srxlev = Q _rxlevmeas - (Q _rxlevmin + Q _{rxlevminoffset} ) - Pcompensation - Qoffset _temp

Squal = Q _qualmeas - (Q _qualmin + Q _{qualminoffset} ) - Qoffset _temp

where:

S-Criteria parameters Srxlev Cell selection RX level value (dB) Squal Cell selection quality value (dB) Qoffset _temp Offset temporarily applied to a cell as specified in [3] (dB) Q _rxlevmeas Measured cell RX level value (RSRP) Q _qualmeas Measured cell quality value (RSRQ) Q _rxlevmin Minimum required RX level in the cell (dBm) Q _qualmin Minimum required quality level in the cell (dB) Q _{rxlevminoffset} Offset to the signaled Q _rxlevmin taken into account in the Srxlev evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5] Q _{qualminoffset} Offset to the signaled Q _qualmin taken into account in the Squal evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5] Compensation
ation If the UE supports the additionalPmax in the NS-PmaxList , if present, in SIB1, SIB3 and SIB5:
[Formula 2]max(P _EMAX1 -P _PowerClass , 0) - (min(P _EMAX2 , P _PowerClass ) - min(P _EMAX1 , P _PowerClass )) (dB);
else:
[Formula 3] max(P _EMAX1 -P _PowerClass , 0) (dB) P _EMAX1 , P _EMAX2 Maximum TX power level an UE may use when transmitting on the uplink in the cell (dBm) defined as P _EMAX in TS 36.101 [33]. P _EMAX1 and P _EMAX2 are obtained from the p-Max and the NS-PmaxList respectively in SIB1, SIB3 and SIB5 as specified in TS 36.331 [3]. P _PowerClass Maximum RF output power of the UE (dBm) according to the UE power class as defined in TS 36.101 [33]

To further explain S-Criteria, in order to provide a more expanded service area to terminals supporting higher maximum transmission power, additional cell selection parameters were defined and pcompensation was also corrected. Mobile communication service providers tended to set the existing Q_rxlevmin value according to the uplink service area. For example, the Q_rxlevmin value was set so that a terminal with a maximum transmission power of 17 dBm could select the corresponding cell. It has become possible to support terminals with higher maximum transmission power, such as from Rel-10 to 20 or 23 dBm, and to provide a more expanded service area to these terminals.

The 3GPP standard introduced a new P_EMAX2 that can be applied by terminals, and for example, when P_PowerClass ≥ P_EMAX2 > P_EMAX1, the definition was corrected so that Pcompensation has a positive value.

Since the SUL frequency (1c-30) exists in a lower frequency band than the NR uplink frequency, it can provide a wider uplink service area. Therefore, for a terminal supporting SUL, it is desirable to select a cell considering the service area of SUL. Even in cells where cell selection is not possible when considering the service area of the NR uplink frequency, cell selection may be possible if the SUL service area is considered.

The disclosed embodiment proposes a method of performing a cell selection operation considering the service area of the SUL frequency. To this end, the base station provides new cell selection parameters, and the terminal can use these to determine whether the S-Criteria formula is satisfied.

FIG. 1D is a flowchart illustrating a method of performing cell selection by considering additional uplink frequencies in one embodiment.

In the first method of initializing the cell selection process considering additional uplink frequencies, it is possible to determine whether both the base station and the terminal support SUL technology (1d-05). The first condition will explain whether both the base station and the terminal support SUL technology. If the first condition is satisfied, the terminal can perform a cell selection operation by considering the influence of SUL (1d-15).

Additionally, a condition that the measured downlink channel quality is lower than the first threshold may be added to the first condition. As described above, the terminal can perform random access with SUL only when the downlink channel quality is lower than the first threshold. Therefore, additional conditions may be further considered. If the first condition is not satisfied, the terminal may perform a cell selection operation in conventional LTE or a cell selection operation without considering the influence of SUL (1d-10). Cell selection operation considering the influence of SUL will be described later. The terminal can receive SUL-related parameters broadcast by the base station and determine whether the base station supports SUL.

In the second method of initializing the cell selection process considering additional uplink frequencies, the terminal can first perform a cell selection operation in conventional LTE or a cell selection operation without considering the influence of SUL (1d-20). Additionally, in the cell selection operation, it may be determined whether the S-Criteria are satisfied and the cell has been selected (1d-25). If the S-Criteria are satisfied and the cell is selected, the terminal can camp on the cell. On the other hand, if the S-Criteria is not satisfied, the terminal may determine whether the first condition is satisfied (1d-30). If the first condition is satisfied, the terminal can perform a cell selection operation by considering the influence of SUL (1d-40). Additionally, if the first condition is not satisfied, the terminal may also search for another cell (1d-35).

FIG. 1E is a flowchart illustrating a process of performing cell selection in consideration of additional uplink frequencies according to an embodiment.

After turning on the power (1e-15), the terminal (1e-05) can scan RF channels in a supportable band depending on the terminal capabilities (1e-20). However, this is only an example, and according to another example, the terminal may scan pre-stored RF channels. The terminal can find the frequency with the strongest signal among channels (1e-25). The terminal can receive system information broadcast by a specific base station (1e-10) at the frequency (1e-30). System information may include parameters related to cell selection.

If the base station can support the SUL function, the system information may also include cell selection parameters related to SUL. Cell selection parameters related to SUL vary depending on the embodiment, and will be described later along with the embodiment. If the terminal can perform a cell selection operation according to the first method or the second method. For example, if the terminal supports the SUL function, it can perform a cell selection operation considering the influence of SUL (1e-35). In other words, it is possible to determine whether to select a cell by substituting the cell selection parameters related to SUL into the S-Criteria formula. If the S-Criteria formula is satisfied and the cell is finally deemed a suitable cell, considering PLMN selection and barring, etc., the terminal can camp on the cell (1e-40).

FIG. 1F is a flowchart for explaining a UE operation that performs cell selection in consideration of additional uplink frequencies in the first embodiment.

In the first embodiment, the terminal may receive the 1st NS-PmaxList, 2nd NS-PmaxList, 1st P_EMAX1, and 2nd P_EMAX1 broadcast from the base station through system information (1f-05). At this time, the system information may include at least one of, for example, RMSI (Remaining Minimum System information) and OSI (Other system information).

NS-PmaxList may be composed of one or more P-Max values and one or more additionalSpectrumEmission values. The P-Max value included in NS-PmaxList can match P_EMAX2 in [Equation 2]. The ASN.1 format of NS-PmaxList below captures ASN.1 from conventional LTE to aid understanding. It is assumed that ASN.1 with a similar configuration will be defined in the next-generation mobile communication system.

NS-PmaxList information element

--ASN1START

NS-PmaxList-r10 ::= SEQUENCE (SIZE (1..maxNS-Pmax-r10)) OF NS-PmaxValue-r10

NS-PmaxValue-r10 ::= SEQUENCE {

additionalPmax-r10 P-Max OPTIONAL, -- Need OP

additionalSpectrumEmission AdditionalSpectrumEmission

}

--ASN1STOP

In the first embodiment, the values of 1st NS-PmaxList and 1st P_EMAX1 may be determined considering the influence of SUL. The values of the 2nd NS-PmaxList and 2nd P_EMAX1 can be determined with the same characteristics as those of conventional LTE. That is, although it depends on the implementation decision, the P_MAX1 value may generally indicate the lowest maximum transmission power value applicable in the cell. At this time, the propagation characteristics of the NR uplink frequency will be considered. For UEs supporting higher maximum transmission power, second NS-PmaxList values may be provided. Usually, the P_EMAX2 value included in NS-PmaxList is greater than the P_EMAX1 value. Setting this value can help ensure that [Formula 2] equals a negative value when the maximum transmission power value of the terminal is greater than the P_EMAX1 value, and ultimately, [Formula 1] becomes greater than 0. An increase in the maximum transmission power of the terminal means an increase in the uplink service area, and [Equation 2] above reflects this so that expansion of the uplink service area can expand the service area of the entire cell. Considering SUL when selecting a cell means expanding the uplink service area.

Therefore, the effect is the same as increasing the maximum transmission power of the terminal. Therefore, in the present invention, the 1st NS-PmaxList and 1st P_EMAX1 values may be determined to be smaller than the 2nd NS-PmaxList and 2nd P_EMAX1 by the value α. At this time, α can be determined by considering the difference in service area or propagation characteristics between the NR uplink frequency and the SUL frequency. For example, the difference value in signal propagation attenuation (pathloss) between the NR uplink frequency and the SUL frequency may be set to α. This setting produces the same effect as increasing the maximum transmission power value of the terminal.

If the first condition is satisfied, the terminal can determine whether [Formula 1] is satisfied by substituting the first NS-PmaxList and first P_EMAX1 values into [Formula 2] (1f-10). If [Formula 1] is satisfied, the terminal can select the corresponding cell. If the first condition is not satisfied, it is possible to determine whether [Formula 1] is satisfied by substituting the first NS-PmaxList and first P_EMAX1 values into [Formula 2] (1f-15). If [Formula 1] is satisfied, the terminal can select the corresponding cell.

In the description of the first embodiment, the description is based on the above-described first method, but this is only an example, and the above-described second method may also be applied.

FIG. 1G is a flowchart for explaining a UE operation that performs cell selection in consideration of additional uplink frequencies in the second embodiment.

In the second embodiment, the terminal receives a second NS-PmaxList and a second P_EMAX1 of the same nature as the conventional LTE from the base station through system information, and additionally indicates the difference in service area or propagation characteristics between the NR uplink frequency and the SUL frequency. The value α can be provided (1g-05). At this time, the system information may include at least one of, for example, RMSI (Remaining Minimum System information) and OSI (Other system information). For example, the difference in signal propagation attenuation (pathloss) between the NR uplink frequency and the SUL frequency can be set to α.

The α value may be set as the difference between Q_rxlevmin and the first threshold. In this case, the base station does not need to separately provide the α value as system information. The Q_rxlevmin value is the minimum received signal strength value (RSRP) in the corresponding cell.

If the terminal satisfies the above-described first condition, the values obtained by subtracting α from each of the second NS-PmaxList and second P_EMAX1 values can be substituted into [Formula 2] to determine whether [Formula 1] is satisfied ( 1g-10). Alternatively, the maximum transmission power of the terminal, that is, the P_PowerClass value plus the α value, can be substituted into [Formula 2] to determine whether [Formula 1] is satisfied. The preprocessing process using the α value is intended to apply this effect because the influence of the SUL frequency has the same effect as increasing the maximum transmission power of the terminal. If [Formula 1] is satisfied, the terminal can select a cell. If the first condition is not satisfied, the second NS-PmaxList and the second P_EMAX1 values can be substituted into [Formula 2] to determine whether [Formula 1] is satisfied (1g-15). If [Formula 1] is satisfied, the terminal can select a cell.

Although the description of the above-described second embodiment is based on the first method, the second method is also applicable.

Figure 1h is a flowchart for explaining a UE operation that performs cell selection in consideration of additional uplink frequencies in the third embodiment.

In the third embodiment, the terminal can receive a separate Q_rxlevmin value considering the influence of SUL through system information from the base station (1h-05). At this time, the system information may include at least one of, for example, RMSI (Remaining Minimum System information) and OSI (Other system information). For example, the difference between the Q_rxlevmin value and the existing Q_rxlevmin value is the difference in service area or propagation characteristics between the NR uplink frequency and the SUL frequency. Alternatively, the base station may provide only the difference value.

If the above-mentioned first condition is satisfied, the terminal can determine whether [Equation 1] is satisfied by substituting the Q_rxlevmin value considering the influence of SUL (1h-10). If [Formula 1] is satisfied, the terminal can select the cell. If the first condition is not satisfied, it can be determined whether [Formula 1] is satisfied by substituting the existing Q_rxlevmin value (1h-15). If [Formula 1] is satisfied, the terminal can select the cell.

Although the description of the third embodiment is based on the first method, the third method is also applicable.

FIG. 2C is a flowchart illustrating a process for setting an additional uplink frequency according to an embodiment.

The terminal (2c-05) can receive system information from the base station (2c-10) (2c-15). System information may include servingCellConfigCommon IE. IE may include configuration information for NR uplink and SUL. Additionally, the configuration information may include not only the NR uplink, but also RACH, PUCCH, and PUSCH configuration information to be applied in the SUL, and frequency information of the SUL, such as center frequency, frequency bandwidth, and frequency band information to which the SUL belongs. Configuration information is cell-specific and is common information to all terminals within the cell.

Additionally, a base station supporting SUL can provide the first threshold required to determine the uplink to attempt random access to the terminals within the cell using system information. A terminal supporting SUL can measure the SSB (Sync Signal Block) broadcasted by the base station in the downlink, derive Reference Signal Received Power (RSRP), and compare this with the first threshold.

If the measured downlink channel quality is lower than the first threshold, the terminal may select the SUL frequency as the uplink to attempt random access (2c-20). Otherwise, the UE may perform random access at the NR uplink frequency.

The terminal can transmit a preamble through the selected uplink (2c-25). The base station that successfully receives the preamble may transmit a random access response message (RAR) to the terminal (2c-30). If preamble transmission is performed in the NR uplink and is considered a transmission failure even after retrying the preset number of retransmissions, the terminal can change to the SUL frequency as the uplink to attempt random access and retry. If SUL deems a transmission failure even after retrying the preset number of retransmissions, the terminal can report the random access failure to the NAS, the upper layer. According to another example, the terminal may re-perform the process of determining the uplink on which to attempt random access and attempt random access on the re-determined uplink. As mentioned above, whether to attempt random access in additional uplinks and the number of retransmissions mentioned above can be indicated by the base station using system information.

The RAR message includes uplink synchronization information, and upon receiving the message, the terminal can start the timeAlignmentTimer timer (2c-35). The random access response message may include scheduling information necessary for transmitting the follow-up message, msg3.

The terminal may transmit an msg3 message to the base station using radio resources indicated by scheduling information (2c-40). The msg3 message may include an RRC Request message. The message may include cause value information indicating the reason for the request along with the connection request.

The base station that successfully receives msg3 can transmit the msg4 message to the terminal (2c-45). The Msg4 message may include an RRC Setup message. The RRC Setup message may include UE-specific configuration information. The configuration information may include PUCCH, PUSCH, and SRS (Sounding Reference Symbol) configuration information for the uplink on which random access was performed. If the uplink on which random access was performed was a SUL frequency, it is considered that SUL has already been configured for the terminal, and the base station must provide the terminal with at least SRS configuration information for the NR uplink. The SRS setting for the NR uplink is for the base station to check the channel status of the NR uplink during data transmission and reception at the SUL frequency. The base station may provide all uplink configuration information for NR uplink to the terminal. This is because the NR uplink maintains sufficient channel quality and uses L1 signaling to switch between the two uplinks. Therefore, there may be two ways to use SUL.

The first method using SUL provides all uplink configuration information in one uplink, and both PUCCH and PUSCH can be transmitted in the uplink. For other uplinks, only SRS configuration information can be provided and channel quality status can be monitored. If the channel quality of other uplinks becomes good, PUCCH and PUSCH can be transmitted to other uplinks by providing additional configuration information.

The second method using SUL provides all uplink configuration information to both uplinks and can indicate the uplink on which the PUSCH will be transmitted through L1 signaling. PUCCH is determined by RRC signaling, and PUCCH and PUSCH do not necessarily need to be transmitted on the same uplink. However, the default uplink on which PUSCH is transmitted is the same as the uplink on which PUCCH is transmitted.

In response to the RRC Setup message, the terminal may transmit an RRC Setup Complete message to the base station (2c-50). The RRC Setup Complete message may include a NAS container. If the terminal has information to deliver to the core network (e.g. AMF), it can deliver it using the NAS container. The AMF that receives the information can report capability information about the terminal to the base station. Capability information is collected by AMF from the terminal during previous connection. If the access corresponds to initial access, AMF does not have capability information about the terminal.

Therefore, in this case, the base station may need to request capability information from the terminal (2c-55). The base station can forward the capability information reported from the terminal to the AMF. Capability information may include whether the terminal supports SUL and information on the frequency range or frequency band capable of supporting SUL. Even if the base station supports the SUL function, if the SUL frequency does not belong to the frequency band or frequency band supported by the terminal, the terminal may be considered as not supporting SUL at the base station.

The base station may transmit SUL-related RRC signaling for the following purposes (2c-60).

First, if SUL is not yet set, RRC signaling can be sent to set SUL. In this case, according to the first or second method using SUL, all uplink configuration information or at least SRS configuration information can be provided for the SUL frequency. Typically, uplink configuration information refers to physical layer configuration information such as RACH, PUSCH, PUCCH, SRS configuration information, antenna, CQI, and power control, MAC layer configuration information, and radio bearer configuration information.

Second, RRC signaling can be transmitted to change the uplink where PUCCH is transmitted. The uplink on which PUCCH is transmitted is an uplink that performs random access by default. The base station can change the uplink in which PUCCH is transmitted using RRC signaling. Uplink configuration information for the uplink where the PUCCH is transmitted must be provided to the terminal in advance or at the same time as the PUCCH is changed.

Third, RRC signaling can be transmitted to disable SUL operation. When SUL operation is canceled, the terminal deletes all SUL frequency configuration information. If the base station maintains SUL operation, it may release one uplink. For example, the second method using SUL may be applied and then switched to the first method using SUL. In this case, the terminal deletes the configuration information of the released uplink, but maintains the SRS configuration information as is.

The base station can use the PDCCH order (2c-65) or after specific RRC signaling to instruct the UE to provide random access to a specific uplink. This is to provide timing for applying synchronization or configuration information for uplink.

In SUL operation, two uplinks are set, and a separate timerAlignmentTimer timer can be set for each uplink (2c-70). The timer can be started or restarted upon receiving uplink synchronization information from the random access process or Timing Advance Command MAC Control Element (TAC MAC CE). The terminal assumes that uplink synchronization is achieved until the timer expires. When the timer expires, the uplink is considered out of synchronization. Therefore, before the timer expires, random access must be re-performed or TAC MAC CE must be received. Another way is to still use a single timerAlignmentTimer timer, although two uplinks are configured, but change the (re)start condition of the timer. For example, when a new uplink is established, the base station may indicate random access for synchronization or provide TAC MAC CE for other uplinks. And, at this point, you can restart the timer.

If one base station operates NR uplink and SUL frequencies, the synchronization of the two uplinks can be set to match or be very similar. Accordingly, the base station can indicate to the terminal whether individual uplink synchronization is necessary. For example, if a single timerAlignmentTimer is set, the two uplink synchronizations are considered aligned. Otherwise, if a separate timerAlignmentTimer is set for each uplink, separate synchronization is considered necessary because the two uplink synchronizations are different.

In the second method using SUL, when the base station determines uplink switching (2c-75), L1 signaling can be transmitted to the terminal (2c-80). The terminal that has received L1 signaling can transmit PUSCH on the uplink indicated by L1 signaling (2c-85).

FIG. 2D is a flowchart illustrating a terminal operation for setting an additional uplink frequency according to an embodiment.

In step 2d-05, the terminal can receive system information from the base station. System information may include servingCellConfigCommon IE. IE may include configuration information for NR uplink and SUL.

In step 2d-10, if the measured downlink channel quality (e.g., Down Link RSRP) is lower than the first threshold, the UE may select the SUL frequency as the uplink to attempt random access. Otherwise, the UE may select NR uplink.

In step 2d-15, the terminal can transmit the preamble through the selected uplink.

In step 2d-20, the terminal may receive a RAR message.

In step 2d-25, the terminal may transmit Msg3 including an RRC Request message.

In step 2d-30, the terminal may receive Msg4 including the RRC Setup message. The configuration information may include PUCCH, PUSCH, and SRS (Sounding Reference Symbol) configuration information for the uplink on which random access was performed. If the uplink on which random access was performed was a SUL frequency, it is considered that SUL has already been configured for the terminal, and the base station must provide the terminal with at least SRS configuration information for the NR uplink.

In step 2d-35, the terminal may transmit an RRC Setup Complete message. The RRC Setup Complete message may include a NAS container. If the terminal has information to deliver to the core network (e.g. AMF), it can deliver it using the NAS container. The AMF that receives the information can report capability information about the terminal to the base station.

In step 2d-40, the UE may report UE capability information upon request from the base station (eg, gNB).

In step 2d-45, the UE may receive SUL-related RRC signaling for the following purposes.

First, if SUL is not yet set, RRC signaling can be sent to set SUL. Second, RRC signaling can be transmitted to change the uplink where PUCCH is transmitted. Third, RRC signaling can be transmitted to disable SUL operation.

In step 2d-50, the UE can perform random access to a specific uplink according to the PDCCH order.

In step 2d-55, the terminal can receive L1 signaling.

In step 2d-60, the UE can transmit PUSCH on the uplink indicated by L1 signaling.

FIG. 3A is a diagram illustrating the structure of an LTE system to which the disclosed embodiment can be applied.

Referring to Figure 3a, as shown, the radio access network of the LTE system includes a next-generation base station (Evolved Node B, hereinafter referred to as ENB, Node B or base station) (3a-05, 3a-10, 3a-15, 3a-20) It may consist of MME (3a-25, Mobility Management Entity) and S-GW (3a-30, Serving-Gateway). The user equipment (hereinafter referred to as UE or terminal) 3a-35 can access an external network through the ENBs 3a-05 to 3a-20 and the S-GW 3a-30.

In FIG. 3A, ENBs 3a-05 to 3a-20 correspond to existing Node B of a universal mobile telecommunications system (UMTS) system. The ENB is connected to the UE (3a-35) through a wireless channel and can perform a more complex role than the existing Node B. In the LTE system, all user traffic, including real-time services such as VoIP (Voice over IP) through the Internet protocol, is serviced through a shared channel, so status information such as buffer status of UEs, available transmission power status, and channel status is required. A device that collects and performs scheduling is required, and ENB (3a-05 ~ 3a-20) can be responsible for this. One ENB can typically control multiple cells. For example, in order to implement a transmission speed of 100 Mbps, the LTE system can use Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology in, for example, a 20 MHz bandwidth. In addition, the LTE system can apply the Adaptive Modulation & Coding (AMC) method, which determines the modulation scheme and channel coding rate according to the channel status of the terminal. The S-GW (3a-30) is a device that provides data bearers, and can create or remove data bearers under the control of the MME (3a-25). The MME is a device that handles various control functions as well as mobility management functions for the terminal and can be connected to multiple base stations.

FIG. 3B is a diagram showing a wireless protocol structure in an LTE system to which the disclosed embodiment can be applied.

Referring to Figure 3b, the wireless protocols of the LTE system include PDCP (Packet Data Convergence Protocol 3b-05, 3b-40), RLC (Radio Link Control 3b-10, 3b-35), and MAC (Medium Access) in the terminal and ENB, respectively. It can be composed of Control 3b-15, 3b-30). PDCP (Packet Data Convergence Protocol) (3b-05, 3b-40) is responsible for operations such as IP header compression/restoration. The main functions of PDCP are summarized as follows.

- Header compression and decompression (ROHC only)

- Transfer of user data

- In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM (Acknowledged Mode)

- Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

- Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM

- Retransmission function (Retransmission of PDCP SDUs at handover and, for split bearers in DC, of PDCP PDUs at PDCP data-recovery procedure, for RLC AM)

- Encryption and decryption function (Ciphering and deciphering)

- Timer-based SDU discard in uplink.

Radio Link Control (hereinafter referred to as RLC) (3b-10, 3b-35) can perform ARQ operations, etc. by reconfiguring PDCP PDU (Packet Data Unit) to an appropriate size. The main functions of RLC are summarized as follows.

- Data transfer function (Transfer of upper layer PDUs)

- ARQ function (Error Correction through ARQ (only for AM data transfer))

- Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

- Re-segmentation of RLC data PDUs (only for AM data transfer)

- Reordering of RLC data PDUs (only for UM and AM data transfer)

- Duplicate detection (only for UM and AM data transfer)

- Error detection function (Protocol error detection (only for AM data transfer))

- RLC SDU deletion function (RLC SDU discard (only for UM and AM data transfer))

- RLC re-establishment function

MAC (3b-15, 3b-30) is connected to several RLC layer devices configured in one terminal, and can perform operations of multiplexing RLC PDUs to MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows.

- Mapping function (Mapping between logical channels and transport channels)

- Multiplexing and demultiplexing function (Multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels)

- Scheduling information reporting

- HARQ function (Error correction through HARQ)

- Priority handling between logical channels of one UE

- Priority handling between UEs by means of dynamic scheduling

- MBMS service identification function

- Transport format selection function

- Padding function

The physical layer (3b-20, 3b-25) channel-codes and modulates the upper layer data, creates OFDM symbols and transmits them to the wireless channel, or demodulates and channel decodes the OFDM symbols received through the wireless channel and transmits them to the upper layer. You can perform the following actions.

FIG. 3C is a diagram showing the structure of a next-generation mobile communication system to which the disclosed embodiment can be applied.

Referring to Figure 3c, as shown, the radio access network of the next-generation mobile communication system (hereinafter referred to as NR or 5G) includes a next-generation base station (New Radio Node B, hereinafter referred to as NR gNB or NR base station) (3c-10) and NR CN (3c). -05, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (3c-15) can access an external network through the NR gNB (3c-10) and NR CN (3c-05).

In Figure 3c, the NR gNB (3c-10) may correspond to an eNB (Evolved Node B) of the existing LTE system. NR gNB is connected to the NR UE (3c-15) through a wireless channel and can provide superior services than the existing Node B. In the next-generation mobile communication system, all user traffic is serviced through a shared channel, so a device is needed to collect status information such as buffer status, available transmission power status, and channel status of UEs and perform scheduling, and perform these operations. NR NB (3c-10) can perform this. One NR gNB can control multiple cells.

In order to implement ultra-high-speed data transmission compared to the current LTE, more than the existing maximum bandwidth can be given, and beamforming technology can be additionally applied using Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology. . Additionally, an adaptive modulation & coding (AMC) method that determines the modulation scheme and channel coding rate according to the channel status of the terminal may be applied. NR CN (3c-05) can perform functions such as mobility support, bearer setup, and QoS setup. NR CN (3c-05) is a device that handles various control functions as well as mobility management functions for the terminal and can be connected to multiple base stations. Additionally, the next-generation mobile communication system can be linked to the existing LTE system, and NR CN (3c-05) can be connected to MME (3c-25) through a network interface. The MME can be connected to an existing base station, eNB (3c-30).

FIG. 3D is a diagram showing the wireless protocol structure of a next-generation mobile communication system to which the disclosed embodiment can be applied. .

Referring to Figure 3d, the wireless protocol of the next-generation mobile communication system is NR PDCP (3d-05, 3d-40), NR RLC (3d-10, 3d-35), and NR MAC (3d-15) in the terminal and NR base station, respectively. , 3d-30).

The main functions of NR PDCP (3d-05, 3d-40) may include some of the following functions:

Header compression and decompression (ROHC only)

- Transfer of user data

- In-sequence delivery of upper layer PDUs

- Out-of-sequence delivery of upper layer PDUs

- Order reordering function (PDCP PDU reordering for reception)

- Duplicate detection of lower layer SDUs

- Retransmission of PDCP SDUs

- Encryption and decryption function (Ciphering and deciphering)

- Timer-based SDU discard in uplink.

In the above, the reordering function of the NR PDCP device refers to the function of rearranging the PDCP PDUs received from the lower layer in order based on the PDCP sequence number (SN), and delivering data to the upper layer in the reordered order. , or may include a function of immediately transmitting without considering the order, may include a function of rearranging the order and recording lost PDCP PDUs, and may include a function of reporting the status of the lost PDCP PDUs to the transmitting side. It may include a function to request retransmission of lost PDCP PDUs.

The main functions of NR RLC (3d-10, 3d-35) may include at least some of the following functions.

- Data transfer function (Transfer of upper layer PDUs)

- In-sequence delivery of upper layer PDUs

- Out-of-sequence delivery of upper layer PDUs

- ARQ function (Error Correction through ARQ)

- Concatenation, segmentation and reassembly of RLC SDUs

- Re-segmentation of RLC data PDUs

- Reordering of RLC data PDUs

- Duplicate detection function

- Protocol error detection

- RLC SDU deletion function (RLC SDU discard)

- RLC re-establishment function

The in-sequence delivery function of the NR RLC layer device refers to the function of delivering RLC SDUs (service data units) received from the lower layer to the upper layer in order, and one RLC SDU is divided into several RLC SDUs. If it is received divided, it may include a function to reassemble and transmit it. In addition, the sequential delivery function includes a function to rearrange received RLC PDUs based on RLC SN (sequence number) or PDCP SN (sequence number), a function to rearrange the order and record lost RLC PDUs, and a function to record lost RLC PDUs. It may include at least one of the functions of reporting status to the sending side. Additionally, the sequential delivery function may include a function to request retransmission of lost RLC PDUs, and if there is a lost RLC SDU, only the RLC SDUs up to the lost RLC SDU are delivered to the upper layer in order. Functions may be included. In addition, the sequential delivery function may include a function of delivering all RLC SDUs received before the timer starts to the upper layer in order if a predetermined timer has expired even if there are lost RLC SDUs, or even if there are lost RLC SDUs, the sequential delivery function may include If the timer of has expired, it may include a function of delivering all RLC SDUs received to date to the upper layer in order.

In addition, the NR RLC layer device processes the RLC PDUs in the order in which they are received (in the order of arrival, regardless of the order of serial numbers and sequence numbers) and delivers them to the PDCP device out of sequence (out-of-sequence delivery). Alternatively, in the case of a segment, segments stored in a buffer or to be received at a later date may be received, reconstructed into one complete RLC PDU, processed, and transmitted to the PDCP device. The NR RLC layer device may not include a concatenation function, and the concatenation function may be performed in the NR MAC layer device or replaced by the multiplexing function of the NR MAC layer device.

In the above, the out-of-sequence delivery function of the NR RLC layer device may represent the function of directly delivering RLC SDUs received from a lower layer to the upper layer regardless of their order. The out-of-order delivery function may include a function of reassembling and delivering one RLC SDU when it is received divided into several RLC SDUs. Additionally, the out-of-order delivery function may include a function of storing the RLC SN or PDCP SN of received RLC PDUs, sorting the order, and recording lost RLC PDUs.

The NR MAC layer device (3d-15, 3d-30) can be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of the NR MAC layer device (3d-15, 3d-30) are the following functions. It may include at least some of them.

- Mapping function (Mapping between logical channels and transport channels)

- Multiplexing and demultiplexing function (Multiplexing/demultiplexing of MAC SDUs)

- Scheduling information reporting

- HARQ function (Error correction through HARQ)

- Priority handling between logical channels of one UE

- Priority handling between UEs by means of dynamic scheduling

- MBMS service identification function

- Transport format selection function

- Padding function

The NR PHY layer devices (3d-20, 3d-25) can channel code and modulate upper layer data, convert it into an OFDM symbol, and transmit it over a wireless channel. Additionally, the NR PHY layer devices 3d-20 and 3d-25 can demodulate OFDM symbols received through a wireless channel, channel decode them, and transmit them to a higher layer.

The present invention proposes a procedure for compressing data and decompressing it at the base station when a terminal transmits data on the uplink in a wireless communication system, and providing a solution when decompression fails, that is, compressing and transmitting data at the transmitting end and compressing and transmitting the data at the receiving end. We propose a support method for the data transmission and reception procedure to decompress this. Additionally, the method proposed in the present invention can also be applied to a procedure in which the base station compresses and transmits data when transmitting downlink data to the terminal, and the terminal receives and decompresses the compressed downlink data. As described above, in the present invention, data is compressed and transmitted at the transmitting end, thereby enabling more data to be transmitted and simultaneously improving coverage.

In the disclosed embodiment, the dual access technology is a technology in which the terminal simultaneously accesses the master cell group (Master Cell Group, MCG) of the master base station and the secondary cell group (SCG) of the secondary base station to transmit and receive data through the two base stations. says Dual access technology can be easily extended to multiple access technology. In other words, using multiple access technology, data can be transmitted and received by simultaneously connecting to one master base station and a plurality of secondary base stations, and data can also be transmitted by simultaneously connecting to a plurality of master base stations and a plurality of secondary base stations. there is.

In the disclosed embodiment, for convenience of explanation, the invention is described and proposed only in terms of dual access technology, and the proposed invention can be easily expanded and applied to multiple access technology.

FIG. 3E is a diagram illustrating dual connectivity bearers or multiple connectivity bearers that can be configured for a terminal to which dual connectivity or multi-connectivity technology is applied in a next-generation mobile communication system according to an embodiment.

In Figure 3e, the terminal (3e-01) can be configured with dual access technology by the base station, and performs dual access with the master base station (3e-02) and the secondary base station (3e-03), and the master base station (3e-02) ) Alternatively, various bearers can be set according to the bearer setting information or logical channel setting information set by the secondary base station (3e-03). Like 3e-05, the terminal 3e-01 can set up an MCG bearer in which the RLC layer device operates in RLC UM mode. In addition, the terminal 3e-01 can set up an MCG bearer in which the RLC layer device operates in RLC AM mode, as in 3e-10, and the PDCP layer device is in the MCG, as in 3e-15, and the RLC layer devices operate in RLC UM mode. You can set up an MCG split bearer operating in this mode. Additionally, like 3e-20, the terminal 3e-01 can set up an MCG split bearer in which the PDCP layer device is in the MCG and the RLC layer devices operate in RLC AM mode.

Additionally, like 3e-25, the terminal 3e-01 can set up an SCG split bearer in which the PDCP layer device is in the SCG and the RLC layer devices operate in RLC UM mode. Additionally, like 3e-30, the terminal 3e-01 can set up an SCG split bearer in which the PDCP layer device is in the SCG and the RLC layer devices operate in RLC AM mode. The terminal (3e-01) can set up an SCG bearer in which the RLC layer device operates in RLC UM mode, as in 3e-35, and can set up an SCG bearer in which the RLC layer device operates in RLC AM mode, as in 3e-40. .

Among the bearers described above, the MCG or SCG split bearer in which RLC layer devices operate in RLC AM mode is advantageous for high-speed data transmission, and among the bearers, the MCG or SCG split bearer in which RLC layer devices operate in RLC UM mode provides reliable service. It has an advantageous structure for redundant data transmission (Packet duplication) to provide.

FIG. 3F is a diagram illustrating a procedure in which the base station sets various bearers described in FIG. 3E to the terminal as RRC messages and sends an RRC message to release the logical channel of the established bearer when the terminal establishes a connection in the disclosed embodiment.

In Figure 3f, if the terminal transmitting and receiving data in RRC connected mode does not transmit or receive data for a predetermined reason or for a certain period of time, the base station may send an RRCConnectionRelease message to the terminal to switch the terminal to RRC idle mode (3f-01). Later, a UE that does not currently have a connection established (hereinafter referred to as an idle mode UE) may perform an RRC connection establishment process with the base station when data to be transmitted is generated.

The terminal can establish reverse transmission synchronization with the base station through a random access process and transmit an RRCConnectionRequest message to the base station (3f-05). The RRCConnectionRequest message may include the terminal's identifier and the reason for establishing a connection (establishmentCause).

The base station may transmit an RRCConnectionSetup message to enable the terminal to establish an RRC connection (3f-10). The RRCConnectionSetup message includes logical channel configuration information or bearer configuration information, and tells the terminal that the RLC layer device described in FIG. 3e sets up an MCG bearer operating in RLC UM mode or that the RLC layer device sets up an MCG bearer operating in RLC AM mode. Configure, or RLC layer devices configure an MCG split bearer operating in RLC AM mode, or RLC layer devices configure an MCG split bearer operating in RLC UM mode, or RLC layer devices configure an SCG bearer operating in RLC UM mode or RLC layer devices configure an SCG bearer operating in RLC AM mode, or RLC layer devices configure an SCG split bearer operating in RLC AM mode, or RLC layer devices configure an SCG split bearer operating in RLC UM mode. can be set.

Additionally, the RRCConnectionSetup message includes cell group configuration information (CellGroupConfig IE), indicates the cell group identifier (CellGroupID) in the cell group configuration information, and lists the logical channels to be released (logicalchannel-ToReleaseList) in the cell group configuration information (CellGroupConfig). By including the information, it is possible to instruct the terminal on which logical channel of which cell group to release. If the cell group identifier is not included in the cell group setting information, the master cell group can be indicated. In addition, the RRCConnectionSetup message includes a message to release the secondary cell group, the secondary cell group release message includes a list of secondary cells to be released (SecondaryCellGroupToReleaseList), a cell group identifier to be released, and the logical channel list to be released in the SCG setting information ( As logicalchannel-ToReleaseList) information is included, it is possible to instruct the terminal which logical channel of which secondary cell group to release.

Additionally, the RRCConnectionSetup message may include RRC connection configuration information, etc. The RRC connection is also called SRB (Signaling Radio Bearer) and can be used to transmit and receive RRC messages, which are control messages between the terminal and the base station.

The terminal that has established the RRC connection can transmit an RRCConnetionSetupComplete message to the base station (3f-15). If the base station does not know the terminal capabilities of the terminal currently establishing a connection or wants to determine the terminal capabilities, it can send a message asking for the terminal capabilities. Additionally, the terminal can send a message reporting its capabilities. In a message reporting its capabilities, the terminal can indicate whether the terminal can use uplink data compression (UDC) and can send it including an indicator indicating this. The RRCConnetionSetupComplete message may include a control message called SERVICE REQUEST in which the terminal requests the MME to set up a bearer for a certain service.

The base station can transmit a SERVICE REQUEST message included in the RRCConnetionSetupComplete message to the MME (3f-20), and the MME can determine whether to provide the service requested by the terminal.

As a result of the determination, if it is decided to provide the service requested by the terminal, the MME may transmit a message called INITIAL CONTEXT SETUP REQUEST to the base station (3f-25). The INITIAL CONTEXT SETUP REQUEST message may include information such as QoS (Quality of Service) information to be applied when setting up a DRB (Data Radio Bearer) and security-related information (e.g., Security Key, Security Algorithm) to be applied to the DRB.

The base station can exchange SecurityModeCommand messages (3f-30) and SecurityModeComplete messages (3f-35) to set security with the terminal. When security settings are completed, the base station can transmit an RRCConnectionReconfiguration message to the terminal (3f-40). The RRCConnectionReconfiguration message includes logical channel configuration information or bearer configuration information and allows the RLC layer device described in FIG. 3e to configure an MCG bearer operating in RLC UM mode, or the RLC layer device configures an MCG bearer operating in RLC AM mode. Or, RLC layer devices configure an MCG split bearer operating in RLC AM mode, or RLC layer devices configure an MCG split bearer operating in RLC UM mode, or RLC layer devices configure an SCG bearer operating in RLC UM mode. Or, RLC layer devices can configure SCG bearers operating in RLC AM mode, or RLC layer devices can configure SCG split bearers operating in RLC AM mode, or RLC layer devices can configure SCG split bearers operating in RLC UM mode. You can.

Additionally, the RRCConnectionReconfiguration message includes cell group configuration information (CellGroupConfig IE), and the RRCConnectionReconfiguration cell group configuration information indicates the cell group identifier (CellGroupID), and the logical channel list to be released (logicalchannel-ToReleaseList) information in the cell group configuration information (CellGroupConfig). Including, it is possible to instruct the terminal on which logical channel of which cell group to release. If the cell group identifier is not included in the cell group setting information, the master cell group can be indicated. In addition, the RRCConnectionReconfiguration message includes a message to release the secondary cell group, the secondary cell group release message includes a list of secondary cells to be released (SecondaryCellGroupToReleaseList), the cell group identifier to be released is included, and the SCG configuration information, that is, the logical to be released, is included. Including channel list (logicalchannel-ToReleaseList) information, it is possible to instruct the terminal which logical channel of which secondary cell group to release.

Additionally, the message includes configuration information of the DRB where user data will be processed, and the terminal can apply the information to configure the DRB and transmit an RRCConnectionReconfigurationComplete message to the base station (3f-45).

The base station that has completed setting up the UE and DRB can send an INITIAL CONTEXT SETUP COMPLETE message to the MME (3f-50), and the MME that receives this sends the S1 BEARER SETUP message and S1 BEARER SETUP RESPONSE to set up the S-GW and S1 bearer. Messages can be exchanged (3f-055, 3f-60). The S1 bearer is a connection for data transmission established between the S-GW and the base station and corresponds 1:1 with the DRB. When all of the above-mentioned processes are completed, the terminal can transmit and receive data through the base station and S-GW (3f-65, 3f-70). As such, the general data transmission process can be largely comprised of three steps: RRC connection setup, security setup, and DRB setup.

Additionally, the base station may transmit an RRCConnectionReconfiguration message to update, add, or change settings to the terminal for a predetermined reason (3f-75). The RRCConnectionReconfiguration message includes logical channel configuration information or bearer configuration information and allows the UE to configure the RLC layer device as described in FIG. 3e to set an MCG bearer operating in RLC UM mode or to configure an MCG bearer to operate in RLC AM mode. Or, RLC layer devices configure an MCG split bearer operating in RLC AM mode, or RLC layer devices configure an MCG split bearer operating in RLC UM mode, or RLC layer devices configure an SCG bearer operating in RLC UM mode. Or, RLC layer devices can configure SCG bearers operating in RLC AM mode, or RLC layer devices can configure SCG split bearers operating in RLC AM mode, or RLC layer devices can configure SCG split bearers operating in RLC UM mode. You can.

Additionally, the RRCConnectionReconfiguration message includes cell group configuration information (CellGroupConfig IE), and the cell group configuration information indicates the cell group identifier (CellGroupID) and the logical channel list to be released (logicalchannel-ToReleaseList) information in the cell group configuration information (CellGroupConfig). Including, it is possible to instruct the terminal on which logical channel of which cell group to release. If the cell group identifier is not included in the cell group setting information, the master cell group may be indicated. In addition, the RRCConnectionReconfiguration message includes a message to release the secondary cell group, and the secondary cell group release message includes a list of secondary cells to be released (SecondaryCellGroupToReleaseList), a cell group identifier to be released, and a logical channel list to be released from the SCG setting information (logical channel- ToReleaseList) information is included to instruct the terminal on which logical channel of which secondary cell group to release.

In the next-generation mobile communication system according to one embodiment, the base station can set up various bearers described in FIG. 3e to the terminal with an RRC message such as 3f-10, 3f-40, or 3f-75 as shown in FIG. 3f. Additionally, the type of bearers set as shown in Figure 3e can be changed to an RRC message such as 3f-10, 3f-40, or 3f-75. For example, RLC layer devices like 3e-15 can release the logical channel (RLC layer device and MAC layer device) corresponding to the SCG of the MCG split bearer operating in RLC UM mode and change it to an MCG bearer like 3e-05. In addition, like 3e-20, RLC layer devices can release the logical channel (RLC layer device and MAC layer device) corresponding to the SCG of the MCG split bearer operating in RLC AM mode and change it to an MCG bearer like 3e-10. , RLC layer devices like 3e-25 can release the logical channels (RLC layer devices and MAC layer devices) corresponding to the MCG of the SCG split bearer operating in RLC UM mode and change it to an SCG bearer like 3e-35. Like 3e-30, RLC layer devices can release the logical channels (RLC layer device and MAC layer device) corresponding to the MCG of the SCG split bearer operating in RLC AM mode and change it to an SCG bearer like 3e-40.

The disclosed embodiment proposes a method for releasing a logical channel of a bearer in a next-generation mobile communication system.

In the disclosed embodiment, the first example of releasing the logical channel of the bearer is as follows.

As shown in Figure 3f, the base station includes cell group configuration information (CellGroupConfig IE) in an RRC message such as 3f-10, 3f-40, or 3f-75, indicates a cell group identifier (CellGroupID) in the cell group configuration information, and sets the cell group configuration. Information (CellGroupConfig) can include the list of logical channels to be released (logicalchannel-ToReleaseList) information to instruct the terminal on which logical channel of which cell group to release. If the cell group identifier is not included in the cell group setting information, the master cell group can be indicated. When the terminal receives an instruction from the base station regarding which logical channel of which bearer of which cell group to release, it can perform a logical channel release procedure for the indicated logical channel.

How to release logical channels using Cell Group Configuration

The network configures the UE with a Master Cell Groups (MCG) and zero or one or more Secondary Cell Groups (SCG). For EN-DC, the MSG is configured as specified in TS 36.331. The network provides the configuration parameters for a cell group in the CellGroupsConfig IE. If the CellGroupConfig does not contain the cellGroupId it applies for the MCG. Otherwise, it applies for an SCG

- if the CellGroupConfig contains the logicalChannel-ToReleaseList :

perform Logical Channel Release

perform Logical Channel Release

The second embodiment of releasing the logical channel of the bearer in the present invention is as follows.

As shown in FIG. 3F, the base station includes a message for releasing the secondary cell group with an RRC message such as 3f-10, 3f-40, or 3f-75, and includes a list of secondary cells to be released (SecondaryCellGroupToReleaseList) in the secondary cell group release message. By including the cell group identifier to be released and the SCG setting information, that is, the logical channel list to be released (logicalchannel-ToReleaseList) information, the terminal can be instructed which logical channel of which secondary cell group to be released. When the terminal receives an instruction from the base station as to which logical channel of which bearer of which cell group to release, it performs a logical channel release procedure for the logical channel instructed.

How to release a logical channel with secondary cell group release

The UE shall

- for each CellGroupId in the SecondaryCellGroupToReleaseList:

reset SCG MAC, if configured;

reset SCG MAC, if configured;

for each logical channel that is part of the SCG configuration:

for each logical channel that is part of the SCG configuration:

*perform logical channel release procedure

release the entire SCG configuration;

release the entire SCG configuration;

In the first or second embodiment of releasing the logical channel of the bearer, a logical channel release procedure is performed. Next, the present invention proposes a specific logical channel release procedure.

The first embodiment of a specific logical channel release procedure in the next-generation mobile communication system of the present invention is as follows.

As shown in FIG. 3F, the terminal configuration information in an RRC message such as 3f-10, 3f-40, or 3f-75 includes a logical channel release list (logicalChannel-ToReleaseList) and a logical channel identifier (LogicalChannelIdentity) to be released from the logical channel release list. ) is indicated, that is, if the logical channel to be released is instructed according to the first or second embodiments of releasing the logical channel of the bearer, the following operation can be performed.

- Release the RLC device or RLC devices corresponding to the indicated logical channel. That is, all untransmitted RLC PDUs or untransmitted RLC SDUs are discarded.

- Instructs the PDCP layer device connected to the indicated logical channel to perform the PDCP data recovery procedure.

- Release the indicated DTCH (Dedicated Traffic channel) logical channel.

Logical channel release procedure

The UE shall:

- for each LogicalChannelIdentity value included in the logicalChannel-ToReleaseList that is part of the current UE configuration (LCH release), or

- for each LogicalChannelIdentity value that is to be released as the result of full configuration option:

release the RLC entity or entities (includes discarding all pending RLC PDUs and RLC SDUs);

release the RLC entity or entities (includes discarding all pending RLC PDUs and RLC SDUs);

trigger the associated PDCP entity to perform data recovery

trigger the associated PDCP entity to perform data recovery

release the DTCH logical channel.

release the DTCH logical channel.

A second specific example of a logical channel release procedure in a next-generation mobile communication system according to an embodiment is as follows.

As shown in Figure 3f, the terminal setting information in an RRC message such as 3f-10, 3f-40, or 3f-75 includes a logical channel release list (logicalChannel-ToReleaseList) and the logical channel identifier to be released in the logical channel release list (LogicalChannelIdentity) If is indicated, that is, if the logical channel to be released is instructed according to the first or second embodiments of releasing the logical channel of the bearer, the following operation is performed.

- Release the RLC device or RLC devices corresponding to the indicated logical channel. That is, all untransmitted RLC PDUs or untransmitted RLC SDUs are discarded.

- If the RLC layer device corresponding to the indicated logical channel operates in RLC AM mode, instructs the connected PDCP layer device to perform the PDCP data recovery procedure.

- Release the indicated DTCH (Dedicated Traffic channel) logical channel.

Logical channel release procedure

The UE shall:

- for each LogicalChannelIdentity value included in the

logicalChannel-ToReleaseList that is part of the current UE

configuration (LCH release), or

- for each LogicalChannelIdentity value that is to be released as the result of full configuration option:

release the RLC entity or entities (includes discarding all pending RLC PDUs and RLC SDUs);

release the RLC entity or entities (includes discarding all pending RLC PDUs and RLC SDUs);

if the RLC entity(or RLC entities) is(are) RLC AM entity(or RLC AM entities), trigger the associated PDCP entity to perform data recovery

if the RLC entity(or RLC entities) is(are) RLC AM entity(or RLC AM entities), trigger the associated PDCP entity to perform data recovery

release the DTCH logical channel.

release the DTCH logical channel.

In the second embodiment of the specific logical channel release procedure, if the RLC layer device operates in RLC UM mode, there is no need to recover even if data loss occurs, so there is no need to perform the PDCP data recovery procedure unnecessarily. In other words, because RLC UM mode tolerates loss and is sensitive to delay, performing the PDCP data recovery procedure only in RLC AM mode is suitable to satisfy service requirements and is more efficient.

A third specific example of a logical channel release procedure in a next-generation mobile communication system according to an embodiment is as follows.

As shown in Figure 3f, the terminal setting information in an RRC message such as 3f-10, 3f-40, or 3f-75 includes a logical channel release list (logicalChannel-ToReleaseList) and the logical channel identifier to be released in the logical channel release list (LogicalChannelIdentity) If is indicated, that is, if the logical channel to be released is instructed according to the first or second embodiment of releasing the logical channel of the bearer, the following operation can be performed.

- Release the RLC device or RLC devices corresponding to the indicated logical channel. That is, all untransmitted RLC PDUs or untransmitted RLC SDUs are discarded.

- If the RLC layer device corresponding to the indicated logical channel operates in RLC AM mode and the PDCP layer device connected to the indicated logical channel is alive (operating), that is, if it has not been released or re-established, PDCP data recovery to the connected PDCP layer device Instructs to carry out the procedure.

- Release the indicated DTCH (Dedicated Traffic channel) logical channel.

Logical channel release procedure

The UE shall:

- for each LogicalChannelIdentity value included in the logicalChannel-ToReleaseList that is part of the current UE configuration (LCH release), or

- for each LogicalChannelIdentity value that is to be released as the result of full configuration option:

release the RLC entity or entities (includes discarding all pending RLC PDUs and RLC SDUs);

release the RLC entity or entities (includes discarding all pending RLC PDUs and RLC SDUs);

if the RLC entity(or RLC entities) is(are) RLC AM entity(or RLC AM entities) and if the associated PDCP entity is neither released nor re-established, trigger the associated PDCP entity to perform data recovery

if the RLC entity(or RLC entities) is(are) RLC AM entity(or RLC AM entities) and if the associated PDCP entity is neither released nor re-established, trigger the associated PDCP entity to perform data recovery

release the DTCH logical channel.

release the DTCH logical channel.

In the third embodiment of the specific logical channel release procedure, if the RLC layer device operates in RLC UM mode, there is no need to recover even if data loss occurs, so there is no need to perform the PDCP data recovery procedure unnecessarily, and the device connected to the indicated logical channel If the PDCP layer device is not operational, has been disabled, or has been re-established, the PDCP data recovery procedure cannot be performed. In other words, if the PDCP layer device is released or re-established, retransmission or data recovery procedures cannot be performed because all data to be retransmitted has been discarded and the buffer has been initialized. That is, when the PDCP layer device connected to the indicated logical channel operates, is not released, and is not re-established, and the RLC layer device operating in RLC AM mode is released (released) or the RLC layer device is re-established (re -established) PDCP data recovery procedure cannot be performed.

In the first, second, and third embodiments of the specific logical channel release procedure of the present invention, a PDCP data recovery procedure is performed.

The present invention proposes an efficient PDCP data recovery procedure in a next-generation mobile communication system as follows.

When the PDCP layer device of the terminal receives a PDCP data recovery procedure request for a bearer or a connected logical channel, it can perform the following procedures.

- If a PDCP status report request is set in the uplink with an indicator requesting a PDCP status report (statusReportRequired), the terminal configures the PDCP status report and delivers it to the lower layer as the first PDCP PDU of data transmission. .

- Retransmission is performed for all PDCP PDUs that were previously transmitted to an RLC layer device operating in re-established or released RLC AM mode, but successful delivery (RLC ACK) is not confirmed from the lower layer (RLC layer device). All retransmissions are performed in ascending order, starting with the data corresponding to the COUNT value of the first PDCP PDU.

PDCP Data Recovery procedure

When upper layers request a PDCP Data Recovery for a radio bearer, the UE shall:

- if the radio bearer is configured by upper layers to send a PDCP status report in the uplink ( statusReportRequired ), compile a status report and submit it to lower layers as the first PDCP PDU for the transmission;

- perform retransmission of all the PDCP PDUs previously submitted to re-established or released AM RLC entity in ascending order of the associated COUNT values from the first PDCP PDU for which the successful delivery has not been confirmed by lower layers.

Figure 3g is a diagram showing the operation of the terminal when it receives a logical channel release instruction from the base station according to one embodiment.

In Figure 3g, the terminal may receive a logical channel release instruction from the base station in the same manner as the first or second embodiments of releasing the logical channel of the bearer (3g-05).

When receiving a logical channel release instruction, the terminal checks which logical channel of which bearer of which cell group should be released, the RLC layer device corresponding to the logical channel operates in RLC AM mode, and the PDCP layer device connected to the logical channel You can check whether has not been re-established or released (3g-10).

If the RLC layer device corresponding to the logical channel operates in RLC AM mode, and the PDCP layer device connected to the logical channel has not been re-established or released, a PDCP data recovery procedure can be performed in the PDCP layer device (3g-15) . If the conditions are not met in 3g-10, the PDCP data recovery procedure may not be performed in the PDCP layer device (3g-20).

According to one embodiment, when a terminal transmits data on the uplink in a wireless communication system, a procedure is proposed to compress the data and decompress it at the base station, and compress the data at the transmitter, including a specific header format and a solution in case of decompression failure. We propose a support method for the data transmission and reception procedure of transmitting and decompressing it at the receiving end. Additionally, according to one embodiment, when the base station transmits downlink data to the terminal, it may be applied to a procedure in which the data is compressed and transmitted, and the terminal receives and decompresses the compressed downlink data. As described above, in the disclosed embodiment, data is compressed and transmitted at the transmitting end, thereby enabling more data to be transmitted and simultaneously improving coverage.

Figure 4e is a diagram illustrating a procedure for configuring whether a base station will perform uplink data compression when a terminal establishes a connection to a network according to an embodiment.

Figure 4e shows the procedure in which the terminal switches from RRC idle mode or RRC inactive mode (RRC Inactive mode or lightly-connected mode) to RRC connected mode in the present invention to establish a connection to the network. This explains the procedure for setting whether to perform uplink data compression (UDC).

In Figure 4e, if the terminal transmitting and receiving data in RRC connected mode does not transmit or receive data for a predetermined reason or for a certain period of time, the base station may send an RRCConnectionRelease message to the terminal to switch the terminal to RRC idle mode (4e-01). Later, a UE that does not currently have a connection established (hereinafter referred to as an idle mode UE) may perform an RRC connection establishment process with the base station when data to be transmitted is generated.

The terminal can establish reverse transmission synchronization with the base station through a random access process and transmit an RRCConnectionRequest message to the base station (4e-05). The RRCConnectionRequest message may include the terminal's identifier and the reason for establishing a connection (establishmentCause).

The base station may transmit an RRCConnectionSetup message to allow the terminal to establish an RRC connection (4e-10). The RRCConnectionSetup message may include information indicating whether to use the uplink data compression method (UDC) for each logical channel (logicalchannelconfig), each bearer, or each PDCP device (PDCP-config). In addition, more specifically, through the RRCConnectionSetup message, it is possible to indicate which uplink data compression method (UDC) will be used only for which IP flow or which QoS flow in each logical channel or bearer or each PDCP device (or SDAP device). According to another example, through the RRCConnectionSetup message, the SDAP device sets information about IP flows or QoS flows to use or not use the uplink data compression method for the SDAP device to determine whether the SDAP device will use the uplink data compression method for the PDCP device. You can also indicate for each QoS flow whether or not to do so. According to another example, the PDCP device may check each QoS flow on its own (based on configuration information set by the base station) through the RRCConnectionSetup message and decide whether to apply the uplink compression method or not.

In addition, when the use of the uplink data compression method is indicated, the identifier for the predefined library or dictionary to be used in the uplink data compression method or the buffer size size to be used in the uplink data compression method is indicated. It can be.

Additionally, the RRCConnectionSetup message may include a setup or release command to perform uplink decompression. Additionally, when configuring to use the uplink data compression method, it can always be set to RLC AM bearer (ARQ function, lossless mode with retransmission function), and can not be set together with header compression protocol (ROHC). Additionally, the RRCConnectionSetup message may include RRC connection configuration information, etc. The RRC connection is also called SRB (Signaling Radio Bearer) and can be used to transmit and receive RRC messages, which are control messages between the terminal and the base station.

The terminal that has established the RRC connection can transmit an RRCConnetionSetupComplete message to the base station (4e-15). If the base station does not know the terminal capabilities of the terminal currently establishing a connection or wants to determine the terminal capabilities, it can send a message asking for the terminal capabilities. And the terminal can also send a message reporting its capabilities. The message may indicate whether the terminal can use uplink data compression (UDC), and may be sent including an indicator indicating this.

The RRCConnetionSetupComplete message may include a control message called SERVICE REQUEST in which the terminal requests the MME to set up a bearer for a certain service. The base station transmits the SERVICE REQUEST message contained in the RRCConnetionSetupComplete message to the MME (4e-20), and the MME can determine whether to provide the service requested by the terminal.

As a result of the determination, if it is decided to provide the service requested by the terminal, the MME may transmit a message called INITIAL CONTEXT SETUP REQUEST to the base station (4e-25). The INITIAL CONTEXT SETUP REQUEST message includes information such as QoS (Quality of Service) information to be applied when setting up a DRB (Data Radio Bearer), and security-related information (e.g. Security Key, Security Algorithm) to be applied to the DRB.

The base station can exchange SecurityModeCommand messages (4e-30) and SecurityModeComplete messages (4e-35) to set security with the terminal. When security settings are completed, the base station can transmit an RRCConnectionReconfiguration message to the terminal (4e-40). The RRCConnectionReconfiguration message may include information indicating whether to use the uplink data compression method (UDC) for each logical channel (logicalchannelconfig), each bearer, or each PDCP device (PDCP-config). In addition, more specifically, the RRCConnectionReconfiguration message can be used to indicate which IP flow or QoS flow to use uplink data compression method (UDC) in each logical channel or bearer or each PDCP device (or SDAP device). Additionally, according to another example, through the RRCConnectionReconfiguration message, information about IP flows or QoS flows to use or not to use the uplink data compression method is set to the SDAP device, so that the SDAP device can use the uplink data compression method to the PDCP device. You can also indicate for each QoS flow whether to use it or not. Additionally, according to another example, the PDCP device may check each QoS flow on its own (based on configuration information set by the base station) through the RRCConnectionReconfiguration message and decide whether to apply the uplink compression method or not.

In addition, if the above indicates to use the uplink data compression method, it indicates the identifier for the predefined library or dictionary to be used in the uplink data compression method or the buffer size to be used in the uplink data compression method. can do. Additionally, the RRCConnectionReconfiguration message may include a setup or release command to perform uplink decompression. In addition, when configuring to use the uplink data compression method above, it can always be set to RLC AM bearer (ARQ function, lossless mode with retransmission function), and can not be set together with header compression protocol (ROHC). Also, The RRCConnectionReconfiguration message includes configuration information of the DRB where user data will be processed, and the terminal can apply the information to configure the DRB and transmit the RRCConnectionReconfigurationComplete message to the base station (4e-45).

The base station that has completed setting up the UE and DRB sends an INITIAL CONTEXT SETUP COMPLETE message to the MME (4e-50), and the MME that receives this sends an S1 BEARER SETUP message and an S1 BEARER SETUP RESPONSE message to set up the S-GW and S1 bearer. can be exchanged (4e-55, 4e-60). The S1 bearer is a connection for data transmission established between the S-GW and the base station and can correspond one-to-one with the DRB. When all of the above-mentioned processes are completed, the terminal can transmit and receive data through the base station and S-GW (4e-65, 4e-70). As such, the general data transmission process largely consists of three steps: RRC connection setup, security setup, and DRB setup. Additionally, the base station may transmit an RRCConnectionReconfiguration message to update, add, or change settings to the terminal for a predetermined reason (4e-75). The RRCConnectionReconfiguration message may include information indicating whether to use the uplink data compression method (UDC) for each logical channel (logicalchannelconfig), each bearer, or each PDCP device (PDCP-config). Also, more specifically, through the RRCConnectionReconfiguration message, it is possible to indicate which uplink data compression method (UDC) will be used only for which IP flow or which QoS flow in each logical channel or bearer or each PDCP device (or SDAP device). In addition, according to another example, the SDAP device can configure whether the SDAP device will use the uplink data compression method for the PDCP device by setting information about the IP flow or QoS flow to use or not use the uplink data compression method through the RRCConnectionReconfiguration message. You can also indicate for each QoS flow whether or not to use it.

Additionally, according to another example, the PDCP device may independently check each QoS flow (check based on configuration information set by the base station) and decide whether or not to apply the uplink compression method.

In addition, if the above indicates to use the uplink data compression method, it indicates the identifier for the predefined library or dictionary to be used in the uplink data compression method, or the buffer size to be used in the uplink data compression method. can do. Additionally, the RRCConnectionReconfiguration message may include a setup or release command to perform uplink decompression. In addition, when configuring to use the uplink data compression method above, it can always be set to RLC AM bearer (ARQ function, lossless mode with retransmission function), and can not be set together with header compression protocol (ROHC).

FIG. 4F is a diagram illustrating a procedure and data configuration for performing uplink data compression according to an embodiment.

In FIG. 4f, uplink data 4f-05 may be generated as data corresponding to services such as video transmission, photo transmission, web search, and VoLTE. Data generated in the application layer device is processed through TCP/IP or UDP corresponding to the network data transmission layer, forms each header (4f-10, 4f-15), and can be delivered to the PDCP layer device. there is. When the PDCP layer device receives data (PDCP SDU) from the upper layer, it can perform the following procedures.

If the PDCP layer device is set to use the uplink data compression method by an RRC message such as 4e-10, 4e-40, or 4e-75 in FIG. 4e, uplink data compression (Uplink) is performed for the PDCP SDU as shown in 4f-20. Data Compression) method is performed to compress the uplink data, configure the corresponding UDC header (header for compressed uplink data, 4f-25), perform encryption (ciphering), and, if set, integrity protection ( You can configure a PDCP PDU by performing integrity protection and configuring the PDCP header (4f-30). The PDCP layer device includes a UDC compression/decompression device, determines whether or not to perform the UDC procedure for each data as set in the RRC message, and can use the UDC compression/decompression device. At the transmitting end, data compression can be performed using a UDC compression device in the transmitting PDCP layer device, and at the receiving end, data decompression can be performed using a UDC decompression device in the receiving PDCP layer device.

The procedure of FIG. 4f described above can be applied not only when the terminal compresses uplink data, but also when compressing downlink data. Additionally, the description of uplink data can be equally applied to downlink data.

Figure 4g is a diagram illustrating an example of an uplink data compression method according to an embodiment.

Figure 4g is a diagram showing an explanation of the DEFLATE-based uplink data compression algorithm, and the DEFLATE-based uplink data compression algorithm is a lossless compression algorithm. The DEFLATE-based uplink data compression algorithm can basically compress uplink data by combining the LZ77 algorithm and Huffman coding. The LZ77 algorithm performs the operation of finding duplicate arrays of data. When finding duplicate arrays, it searches for duplicate arrays within the sliding window through a sliding window. If there are duplicate arrays, it searches for duplicate arrays within the sliding window. Data compression is performed by expressing the location and degree of overlap in terms of length. The sliding window is also called a buffer in uplink data compression (UDC), and can be set to 8 kilobytes or 32 kilobytes. In other words, the sliding window or buffer can perform compression by recording 8192 or 32768 characters, finding duplicate arrays, and expressing them in position and length. Therefore, because the LZ77 algorithm is a sliding window method, that is, it updates previously coded data in the buffer and then performs coding on the immediately following data, it can have a correlation between consecutive data.

Therefore, only when the coded data first is decoded properly can the subsequent data be decoded normally. Codes expressed in position and length and compressed using the LZ77 algorithm (expression of position, length, etc.) are compressed once more through Huffman coding. Hoffman coding can perform compression once again by finding duplicated codes and using short notations for codes with a high degree of duplication and long notations for codes with a low degree of duplication. Hoffman coding is a prefix code and is an optimal coding method in which all codes have distinct characteristics (Uniquely decodable).

As described above, at the transmitting end, the LZ77 algorithm is applied to the original data (4g-05) to perform encoding (4g-10), the buffer is updated (4g-15), and a checksum (or checksum) for the contents (or data) of the buffer is performed. checksum) bits can be created and configured in the UDC header. Checksum bits can be used at the receiving end to determine whether the buffer state is valid. Codes encoded with the LZ77 algorithm can be compressed once again with Hoffman coding and transmitted as uplink data (4g-25).

The receiving end can perform a decompression procedure on the received compressed data in the opposite direction of the sending end. That is, the receiving end can perform Hoffman decoding (4g-30), update the buffer (4g-35), and check whether the updated buffer is valid using the checksum bits of the UDC header. At the receiving end, if it is determined that the checksum bits are error-free, decoding is performed using the LZ77 algorithm (4g-40) to decompress the data, restore the original data, and transmit it to the upper layer (4g-45).

As mentioned above, because the LZ77 algorithm is a sliding window method, that is, it updates previously coded data in the buffer and then codes the next data again, it can have a correlation between consecutive data. Therefore, only when the coded data first is decoded properly can the subsequent data be decoded normally. Therefore, the receiving PDCP layer device checks the PDCP serial number of the PDCP header, checks the UDC header (checks the indicator indicating whether data compression was performed or not), and sorts the data to which the data compression procedure has been applied in ascending order of the PDCP serial number. The data decompression procedure can be performed in this order.

The procedure for the base station to perform uplink data compression (UDC) settings on the terminal and the procedure for the terminal to perform uplink data compression (UDC) according to one embodiment are as follows.

In FIG. 4e, the base station can configure or disable uplink data compression on the bearer or logical channel for which the RLC AM mode is set to the terminal through an RRC message such as 4e-10, 4e-40, or 4e-75. Additionally, the base station can reset the UDC device (or protocol) of the PDCP layer device of the terminal using the RRC message. Resetting the UDC device (or protocol) means resetting the UDC buffer for uplink data compression of the terminal, and is intended to synchronize the UDC buffer of the terminal and the UDC buffer for decompression of uplink data of the base station. The operation of resetting the buffer of the UDC device is defined by modifying the existing PDCP control PDU or defining a new PDCP control PDU, so that the transmitting end (base station) resets the UDC buffer of the receiving end (terminal) with a PDCP control PDU instead of an RRC message. It can be used for synchronization of user data compression and decompression between transmitting and receiving ends.

In addition, using the RRC message, it can be determined whether to perform uplink data compression for each bearer, logical channel, or PDCP layer device, and more specifically, each IP flow (or QoS) within one bearer, logical channel, or PDCP layer device. You can set whether to perform uplink data decompression for each flow) or not.

Settings for each QoS flow can be made by setting an indicator or information in the PDCP layer device to indicate which QoS flows will perform uplink data decompression and which QoS flows will not perform uplink data decompression. In addition, the settings for each QoS flow are set to the SDAP layer device rather than the PDCP layer device, so that the SDAP layer device determines whether to perform uplink data decompression for the QoS flow when mapping each QoS flow to each bearer. I can give you instructions.

Additionally, with the RRC message, the base station can set the PDCP discard timer value to the terminal. At this time, the PDCP discard timer value may be set separately as a PDCP discard timer value for data to which uplink data compression is not performed and a PDCP discard timer value for data to which uplink data compression is applied.

If the terminal is configured to perform uplink data compression for a certain bearer or logical channel or PDCP layer device (or for any QoS flows of a certain bearer or logical channel or PDCP layer device) through an RRC message, The buffer can be reset in the UDC device of the PDCP layer device accordingly and the uplink data compression procedure can be prepared. And when the terminal receives data from the upper layer (PDCP SDU), if the PDCP layer device is configured to perform uplink data compression, it can perform uplink data compression on the received data.

If the PDCP layer device is set to perform uplink data compression only for specific QoS flows, the terminal determines whether to perform uplink data compression by checking the instruction of the upper SDAP layer or the QoS flow identifier and performs uplink data compression. can do. And if uplink data compression (UDC) is performed and the buffer is updated according to data compression, the terminal can configure a UDC buffer. When the UE performs uplink data compression (UDC), it can compress the PDCP SDU received from the upper layer into UDC compressed data (UDC block) with a smaller size.

And you can configure the UDC header for the compressed UDC compressed data. The UDC header may include an indicator indicating whether uplink data compression was performed or not. For example, in the UDC header, if the 1-bit indicator is 0, UDC may be applied, and if the 1-bit indicator is 1, UDC may not be applied.

In the case where uplink data compression is not applied, compression has already been performed at the upper layer (e.g., application layer), so even if the uplink data compression procedure is performed on the PDCP layer device, the compression rate is very low and the compression procedure causes This may be because only the processing burden at the transmitting end is increased, and may include cases where data compression cannot be performed using the UDC compression method (DEFLATE algorithm) because the PDCP SDU data structure received from the upper layer does not have a repetitive data structure.

Uplink data compression (UDC) is performed on the data (PDCP SDU) received from the upper layer, and if the UDC buffer is updated, the PDCP layer device at the receiving end calculates checksum bits to confirm the validity of the updated UDC buffer. It can be configured by including it in the UDC buffer. Here, the checksum bits have a predetermined length and may consist of, for example, 4 bits.

If integrity protection is set for data with or without uplink data decompression, the terminal can perform integrity protection, ciphering, and transmit it to the lower layer.

Figure 4h is a diagram explaining a UDC header according to one embodiment.

In FIG. 4h, when UDC is applied (uplink data compression is performed), the PDCP PDU may be composed of a PDCP header, a UDC header (4h-05), and a compressed UDC data block. The UDC header may have a size of 1 byte and may be composed of an F field (4h-10), an R field (4h-15), and checksum bits (4h-20).

The F field (4h-10) in the UDC header is a field that indicates whether UDC has been applied to the UDC data block or not. For example, it may indicate whether uplink data compression has been performed or not. In other words, when the transmitting PDCP layer device receives data (PDCP SDU) from the upper layer and applies UDC, it can indicate this by setting the F field to 1, for example, and if UDC is not applied, by setting the F field to 0. there is. The reason for not applying the UDC procedure is that compression has already been performed at the upper layer (e.g., the application layer), so even if the PDCP layer device performs the uplink data compression procedure, the compression rate is very low and the processing burden at the transmitter due to the compression procedure is high. This may be due to weighting. The PDCP layer device receives instruction information for each IP flow or QoS flow from the SDAP layer device and can determine whether to apply UDC. The PDCP layer device or UDC device can determine whether to apply UDC to each IP flow or QoS flow. Whether to apply UDC can be determined based on the configuration information of the RRC message set by the base station.

The R bits (4h-15) of FIG. 4h, reserved bits, indicate whether to perform a reset on the UDC buffer, indicate whether to use the current data to update the UDC buffer, or indicate predefined dictionary information (Dictionary ) can be defined and used to indicate whether to use.

The checksum bits (4h-20) of FIG. 4h can be used to verify the validity of the transmission UDC buffer contents used when applying UDC at the transmitter, as described above. Additionally, when decompressing UDC-applied data at the receiving end, checksum bits can be calculated and used to confirm the validity of the received UDC buffer contents. Checksum bits can have a length of 4 bits, and a longer length value can be defined to increase the likelihood of validation.

Figures 4i and 4j are diagrams illustrating a procedure for configuring data (PDCP PDU) by defining a new field to reduce overhead in the PDCP header and applying the new field to reduce overhead, according to an embodiment.

As shown in Figure 4i, a new U field (4i-10) can be applied to the PDCP header (4i-05). The U field may indicate whether UDC has been applied to the PDCP SDU of the PDCP PDU or not. Additionally, the U field may indicate whether a UDC header is present in the PDCP SDU. The reason why the 1-bit indicator in the PDCP header indicates whether UDC is applied or whether a UDC header exists is because compression has already been performed at the upper layer, for example at the application layer, that is, the upper layer already has a compression function. In this case, even if the PDCP layer device performs the uplink data compression procedure, the compression rate is very low and the compression procedure may only increase the processing burden at the transmitter.

The PDCP layer device can receive instruction information for each IP flow or QoS flow from the SDAP layer device and determine whether to apply UDC. The PDCP layer device or UDC device determines whether to apply UDC to each IP flow or QoS flow. It can be judged based on the configuration information of the configured RRC message.

In FIG. 4J, the transmitting PDCP layer device (4j-01) configured with the uplink data compression (UDC) procedure does not apply UDC to the upper layer data (4j-15) and uses the U field in the PDCP header (4j-20). You can set it to 0 (or 1) and omit the UDC header. In addition, a transmitting PDCP layer device (4j-01) configured with an uplink data compression (UDC) procedure sets the U field to 1 (or 1) in the PDCP header (4j-10) if UDC is applied to the upper layer data (4j-05). 0) and can be inserted by configuring the UDC header. Therefore, the PDCP layer device at the receiving end can know that there is no UDC header if the U field in the PDCP header is 0, and UDC processing in the PDCP SDU, that is, the uplink data decompression procedure, can be omitted. However, if the U field in the PDCP header is 1, the PDCP layer device at the receiving end can tell that there is a UDC header, read the first UDC header from the PDCP SDU, check the validity of the buffer with the checksum bits of the UDC header, and check the remaining The original data can be restored by performing uplink data decompression on the PDCP SDU.

Therefore, the 1-bit U field of the PDCP header proposed in Figure 4i is used when configuring a PDCP PDU for data (PDCP SDU) to which the UDC procedure (uplink data compression procedure) is not applied when transmitting data from the transmitting end to the receiving end. A 1-bit indicator (4i-10) indicates that there is no UDC header and that the UDC procedure has not been applied, so the UDC header can be omitted, saving 1 byte of overhead. The U field can be used only when uplink data compression settings are set in the bearer or logical or PDCP layer device, and in other settings, it may be used as a reserved field or a field with other functions.

Figure 4k is a diagram showing the operation of a transmitting end (terminal) of a UDC processing method that reduces overhead according to an embodiment.

In Figure 4k, the transmitting PDCP layer device (4k-01) in which the terminal's uplink data compression (UDC) procedure is set can receive higher layer data (4k-05) and determine whether to apply UDC (4k-10). Here, the PDCP layer device can determine whether to apply UDC by receiving instruction information for each IP flow or QoS flow from the SDAP layer device, and the PDCP layer device or UDC device can determine whether to apply UDC to each IP flow or QoS flow. Whether or not UDC is applied can be determined based on the configuration information of the RRC message set by the base station.

If UDC is not applied to upper layer data, the U field can be set to 0 (or 1) in the PDCP header and the UDC header can be omitted (4k-20), and if UDC is applied to higher layer data, the U field can be set to 0 (or 1) in the PDCP header. You can insert the field by setting it to 1 (or 0) and configuring the UDC header (4k-15).

Figure 4l is a diagram showing the operation of a receiving end (base station) of a UDC processing method for reducing overhead according to an embodiment.

In FIG. 4l, when lower layer data is received (4l-05), the PDCP layer device (4l-01) at the receiving end of the base station can check whether UDC is applied through a 1-bit indicator in the PDCP header (4l-10). If the U field in the PDCP header is 0, the PDCP layer device at the receiving end of the base station can see that there is no UDC header, and UDC processing in the PDCP SDU, that is, the uplink data decompression procedure, can be omitted (4l-20).

However, if the U field in the PDCP header is 1, the PDCP layer device at the receiving end of the base station can tell that there is a UDC header, read the first UDC header from the PDCP SDU, and check the validity of the buffer with the checksum bits of the UDC header. , the original data can be restored by performing uplink data decompression on the remaining PDCP SDUs (4l-15).

According to one embodiment, the transmitting end may independently process data to which the UDC procedure is applied and data to which the UDC procedure is not applied, by using the 1-bit indicator of the PDCP header. For example, independent PDCP serial numbers can be assigned to data to which the UDC procedure is applied and data to which the UDC procedure is not applied. In other words, the receiving end can use the 1-bit indicator of the PDCP header to independently operate the reception window, window variables, and timer of the PDCP layer device independently for data to which the UDC procedure has been applied and data to which the UDC procedure has not been applied. there is.

In another method, a common PDCP serial number is assigned to data to which the UDC procedure is applied and data to which the UDC procedure is not applied, and at the receiving end, a header (PDCP header or Data can be processed independently by distinguishing them from each other with a 1-bit indicator in the UDC header, and independently processed data is delivered to the upper layer in the order in which it was processed first, but within data to which the UDC procedure is applied, the data is processed in ascending order of PDCP serial number. Data that is not applied to the UDC procedure can be transmitted to the upper layer in ascending order of the PDCP serial number.

In other words, at the receiving end, when the receiving PDCP layer transmits data to the upper layer, it does not simply transmit data in ascending order of PDCP serial number, but separates the data into data to which the UDC procedure has been applied and data to which the UDC procedure has not been applied, and to which the UDC procedure is applied. Data can be delivered to the upper layer in ascending order of PDCP serial number, and data to which the UDC procedure has not been applied can be delivered to the upper layer in ascending order of PDCP serial number.

Figure 4m is a block diagram of a terminal according to one embodiment.

Referring to Figure 4m, the terminal may include an RF (Radio Frequency) processing unit (4m-10), a baseband processing unit (4m-20), a storage unit (4m-30), and a control unit (4m-40). there is. However, this is only an example, and the components of the base station 1600 are not limited to the above-described examples.

The RF processing unit 4m-10 can perform functions for transmitting and receiving signals through a wireless channel, such as band conversion and amplification of signals. The RF processing unit (4m-10) upconverts the baseband signal provided from the baseband processing unit (4m-20) into an RF band signal and transmits it through an antenna, and converts the RF band signal received through the antenna into a baseband signal. Can be down-converted. For example, the RF processing unit (4m-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. there is. In Figure 4m, only one antenna is shown, but the terminal may be equipped with multiple antennas. Additionally, the RF processing unit 4m-10 may include multiple RF chains. Furthermore, the RF processing unit 4m-10 can perform beamforming. For beamforming, the RF processing unit 4m-10 can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. Additionally, the RF processing unit can perform MIMO and can receive multiple layers when performing MIMO operations. The RF processing unit 4m-10 can perform reception beam sweeping by appropriately setting a plurality of antennas or antenna elements under the control of the control unit, or adjust the direction and beam width of the reception beam so that the reception beam coordinates with the transmission beam. .

The baseband processing unit 4m-20 can perform a conversion function between baseband signals and bit strings according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit 4m-20 may generate complex symbols by encoding and modulating the transmission bit string. Additionally, when receiving data, the baseband processing unit 4m-20 can restore the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 4m-10. For example, when following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit 4m-20 generates complex symbols by encoding and modulating the transmission bit string, and maps the complex symbols to subcarriers. After that, OFDM symbols can be configured through IFFT (inverse fast Fourier transform) operation and CP (cyclic prefix) insertion. In addition, when receiving data, the baseband processing unit 4m-20 divides the baseband signal provided from the RF processing unit 4m-10 into OFDM symbols and maps them to subcarriers through FFT (fast Fourier transform) operation. After restoring the signals, the received bit string can be restored through demodulation and decoding.

The baseband processing unit 4m-20 and the RF processing unit 4m-10 can transmit and receive signals as described above. Accordingly, the baseband processing unit 4m-20 and the RF processing unit 4m-10 may be referred to as a transmitting unit, a receiving unit, a transceiving unit, or a communication unit. Furthermore, at least one of the baseband processing unit 4m-20 and the RF processing unit 4m-10 may include multiple communication modules to support multiple different wireless access technologies. Additionally, at least one of the baseband processing unit 4m-20 and the RF processing unit 4m-10 may include different communication modules to process signals in different frequency bands. For example, different wireless access technologies may include LTE networks, NR networks, etc. Additionally, different frequency bands may include a super high frequency (SHF) (e.g., 2.5GHz, 5Ghz) band and a millimeter wave (e.g., 60GHz) band.

The storage unit 4m-30 may store data such as basic programs, application programs, and setting information for operation of the above-described terminal. The storage unit 4m-30 may provide stored data upon request from the control unit 4m-40.

The control unit 4m-40 can control the overall operations of the terminal. For example, the control unit 4m-40 may transmit and receive signals through the baseband processing unit 4m-20 and the RF processing unit 4m-10. Additionally, the control unit 4m -40 can record and read data in the storage unit 4m -40. For this purpose, the control unit 4m-40 may include at least one processor. For example, the control unit 4m-40 may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

Figure 4n is a block diagram of a base station according to one embodiment.

Referring to Figure 4n, the base station will include an RF processing unit (4n-10), a baseband processing unit (4n-20), a backhaul communication unit (4n-30), a storage unit (4n-40), and a control unit (4n-50). You can. However, this is only an example, and the components of the base station 1600 are not limited to the above-described examples.

The RF processing unit 4n-10 can perform functions for transmitting and receiving signals through a wireless channel, such as band conversion and amplification of signals. That is, the RF processing unit 4n-10 upconverts the baseband signal provided from the baseband processing unit 4n-20 into an RF band signal and transmits it through an antenna, and converts the RF band signal received through the antenna into a baseband signal. It can be down-converted into a signal. For example, the RF processing unit 4n-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In Figure 4n, only one antenna is shown, but the base station may be equipped with multiple antennas. Additionally, the RF processing unit 4n-10 may include multiple RF chains. Furthermore, the RF processing unit 4n-10 can perform beamforming. For beamforming, the RF processing unit 4n-10 can adjust the phase and size of each signal transmitted and received through a plurality of antennas or antenna elements. The RF processing unit 4n-10 can perform downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 4n-20 can perform a conversion function between baseband signals and bit strings according to the physical layer specifications of the wireless communication system. For example, when transmitting data, the baseband processing unit 4n-20 may generate complex symbols by encoding and modulating the transmission bit stream. Additionally, when receiving data, the baseband processing unit 4n-20 can restore the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 4n-10. For example, when following the OFDM method, when transmitting data, the baseband processing unit 4n-20 generates complex symbols by encoding and modulating the transmission bit string, maps the upper complex symbols to subcarriers, and then performs IFFT operation. And OFDM symbols can be configured through CP insertion. In addition, when receiving data, the baseband processing unit 4n-20 divides the baseband signal provided from the RF processing unit 4n-10 into OFDM symbols, restores the signals mapped to subcarriers through FFT operation, and then , the received bit string can be restored through demodulation and decoding. The baseband processing unit 4n-20 and the RF processing unit 4n-10 can transmit and receive signals as described above. Accordingly, the baseband processing unit 4n-20 and the RF processing unit 4n-10 may be referred to as a transmitting unit, a receiving unit, a transceiving unit, a communication unit, or a wireless communication unit.

The communication unit 4n-30 may provide an interface for communicating with other nodes in the network.

The storage unit 4n-40 can store data such as basic programs, application programs, and setting information for operation of the main base station. In particular, the storage unit 4n-40 can store information about bearers assigned to the connected terminal, measurement results reported from the connected terminal, etc. Additionally, the storage unit 4n-40 may store information that serves as a criterion for determining whether to provide or suspend multiple connections to the terminal. Additionally, the storage unit 4n-40 may provide stored data upon request from the control unit 4n-50.

The control unit 4n-50 can control the overall operations of the base station. For example, the control unit 4n-50 may transmit and receive signals through the backhaul communication unit 4n-30 through the baseband processing unit 4n-20 and the RF processing unit 4n-10. Additionally, the control unit 4n-50 can write and read data into the storage unit 4n-40. For this purpose, the control unit 4n-50 may include at least one processor. Meanwhile, the embodiments of the present invention disclosed in the specification and drawings are merely provided as specific examples to easily explain the technical content of the present invention and to facilitate understanding of the present invention, and are not intended to limit the scope of the present invention. In other words, it is obvious to those skilled in the art that other modifications based on the technical idea of the present invention can be implemented. Additionally, each of the above embodiments can be operated in combination with each other as needed. For example, parts of Embodiments 1, 2, 3, and 4 of the present invention can be combined to operate the base station and the terminal. In addition, although the above embodiments were presented based on the NR system, other modifications based on the technical idea of the above embodiments may be implemented in other systems such as FDD or TDD LTE systems.

In addition, the specification and drawings disclose preferred embodiments of the present invention, and although specific terms are used, these are merely used in a general sense to easily explain the technical content of the present invention and aid understanding of the present invention. It is not intended to limit the scope of the invention. It is obvious to those skilled in the art that in addition to the embodiments disclosed herein, other modifications based on the technical idea of the present invention may be implemented.

Claims (18)

In a method for a terminal to perform cell selection in a wireless communication system,
Receiving system information from a base station;
If the terminal supports SUL (supplementary uplink) for a cell and the system information includes cell selection information related to the SUL for the cell, a cell selection parameter is obtained from the cell selection information related to the SUL, and the terminal If SUL for the cell is supported and the system information does not include cell selection information related to the SUL for the cell, cell selection information related to the uplink (UL, uplink) for the cell included in the system information Obtaining cell selection parameters; and
Method comprising: performing cell selection for the cell based on the cell selection parameter.
delete The method of claim 1, wherein obtaining the cell selection parameter comprises:
If the terminal does not support SUL for the cell, obtaining a cell selection parameter from cell selection information related to uplink for the cell included in the system information.
The method of claim 1, wherein the cell selection information related to the SUL is:
Associated with the minimum required received power value for the SUL within the cell.
The method of claim 4, wherein performing the cell selection comprises:
determining a cell selection received power value based on the minimum required received power value for the SUL for the cell and the measured cell received power value; and
Method comprising: selecting the cell based on the result of the decision.
The method of claim 1, wherein the system information is:
A method including remaining minimum system information (RMSI).
In a method performed by a base station in a wireless communication system,
Generating system information including cell selection information related to uplink (UL) for a cell; and
Including: transmitting the system information to the terminal,
If the base station supports SUL (supplementary uplink) for the cell, the system information further includes cell selection information related to the SUL for the cell,
Cell selection information related to the SUL for the cell is used for a cell selection procedure for the cell if the terminal supports SUL for the cell.
The method of claim 7, wherein the cell selection information related to the SUL is:
Associated with the minimum required received power value for the SUL in the cell.
The method of claim 7, wherein the system information is:
A method including remaining minimum system information (RMSI).
In a terminal that performs cell selection, the terminal:
transceiver, and
Including a processor coupled to the transceiver,
The processor,
Receive system information from a base station,
If the terminal supports SUL (supplementary uplink) for a cell and the system information includes cell selection information related to the SUL for the cell, obtain a cell selection parameter from the cell selection information related to the SUL,
If the terminal supports SUL for the cell and the system information does not include cell selection information related to the SUL for the cell, the uplink (UL, uplink) information for the cell included in the system information Obtain cell selection parameters from cell selection information,
A terminal configured to perform cell selection for the cell based on the cell selection parameter.
delete The method of claim 10, wherein the processor:
If the terminal does not support SUL for the cell, the terminal is configured to obtain a cell selection parameter from cell selection information related to uplink for the cell included in the system information.
The method of claim 10, wherein the cell selection information related to the SUL is:
Associated with the minimum required received power value for the SUL in the cell.
The method of claim 13, wherein the processor:
Based on the minimum required received power value for the SUL for the cell and the measured cell received power value, determine a cell selection received power value,
A terminal configured to select the cell based on a result of the decision.
The method of claim 10, wherein the system information is:
A terminal containing remaining minimum system information (RMSI).
In a base station in a wireless communication system, the base station,
transceiver; and
Including a processor coupled to the transceiver,
The processor,
Generate system information including cell selection information related to uplink (UL, uplink) for the cell,
Configured to transmit the system information to the terminal,
If the base station supports SUL (supplementary uplink) for the cell, the system information further includes cell selection information related to the SUL for the cell,
Cell selection information related to the SUL for the cell is used for a cell selection procedure for the cell if the terminal supports SUL for the cell.
The method of claim 16, wherein the cell selection information related to the SUL is:
A base station associated with the minimum required received power value for the SUL in the cell.
The method of claim 16, wherein the system information is:
A base station, including remaining minimum system information (RMSI).