KR20100020753A - Method for scheduling uplink in wireless communication system - Google Patents

Abstract

PURPOSE: An uplink scheduling method for transmitting the upturn grant from the wireless telecommunications system through PDCCH is provided to prevent the inefficient use of 'the radio resource assigned to the uplink scheduling by preventing the delay of the data processing. CONSTITUTION: The uplink scheduling information which is uplink grant is transmitted(S100). In case the uplink data according to the uplink tendency grant is not received, the uplink tendency grant is retransmitted(S120). The uplink scheduling information is the scheduling information of the PUSCH(Physical Uplink Shared Channel). The uplink tendency grant is transmitted through the PDCCH(Physical Downlink Control Channel).

Description

Uplink scheduling method in wireless communication system {METHOD FOR SCHEDULING UPLINK IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to wireless communication, and more particularly, to an uplink scheduling method.

The next generation multimedia wireless communication system, which is being actively researched recently, requires a system capable of processing and transmitting various information such as video, wireless data, etc., out of an initial voice-oriented service. Wireless communication systems must be able to process large amounts of data at high speed. The purpose of a wireless communication system is to enable a large number of users to communicate reliably regardless of location and mobility. For reliable high speed communication between the base station and the terminal, the base station allocates a radio resource to the terminal. Radio resource allocation methods (Dynamic Scheduling) and Persistent Scheduling (Resource Scheduling). In the dynamic allocation method, scheduling information is required through a control signal whenever data is transmitted or received. On the other hand, since the permanent allocation method uses preset information, scheduling information through a control signal is not required each time data is transmitted or received. Hereinafter, downlink means communication from the base station to the terminal, and uplink means communication from the terminal to the base station.

The wireless channel has a Doppler effect due to path loss, noise, fading due to multipath, intersymbol interference (ISI), or mobility of UE. Doppler effect). Various techniques have been developed to overcome the non-ideal characteristics of the wireless channel and to improve the reliability of the wireless communication.

Among the techniques for improving the reliability of wireless communication, there is a hybrid automatic repeat reQuest (HARQ) scheme. HARQ is a combination of forward error correction (FEC) and automatic repeat request (ARQ). The HARQ-type receiver basically attempts error correction on received data and determines whether to retransmit using an error detection code. The error detection code may use a cyclic redundancy check (CRC). If the error of the received data is not detected through the CRC detection process, the receiver sends an acknowledgment (ACK) signal to the transmitter to inform the transmitter of the reception success. When an error of received data is detected through the CRC detection process, the receiver sends a negative acknowledgment (NACK) signal to the transmitter. The transmitter may retransmit data when the NACK signal is received. As such, the ACK signal and the NACK signal assume that the receiver receives the received data. However, the receiver may not receive the received data in some cases. The receiver does not detect any received data (No Detection). This is hereinafter referred to as received data loss.

If uplink data is lost, the processing method becomes a problem. When the base station performs uplink scheduling by the dynamic allocation method, the terminal may not receive the uplink scheduling information. Since the terminal cannot transmit the uplink data, the base station determines that the uplink data loss. If the base station does not process uplink data loss quickly, data processing is delayed between the base station and the terminal. This causes unnecessary power consumption. In addition, the radio resources allocated by the base station to the uplink scheduling is not utilized, and thus limited radio resources are inefficiently used. This degrades the overall system performance.

Accordingly, there is a need for an uplink scheduling method that can quickly handle uplink data loss.

An object of the present invention is to provide an efficient uplink scheduling method.

In one aspect, there is provided an uplink scheduling method in a wireless communication system. The method includes transmitting an uplink grant, which is uplink scheduling information, and retransmitting the uplink grant when uplink data according to the uplink grant is not received.

In another aspect, there is provided an uplink scheduling method in a wireless communication system. The method includes transmitting an uplink grant that is uplink scheduling information and retransmitting the uplink grant when uplink data according to the uplink grant is not received, wherein the uplink grant transmits the uplink data. A first transmission power control command for controlling power, wherein the first transmission power control command reflects a first correction value determined by using a reception power of uplink data received within a first update window, and the uplink grant Is transmitted in a second update window that is a subsequent update window of the first update window.

The base station can quickly handle the uplink data loss, it is possible to prevent the delay of data processing between the base station and the terminal. This can reduce power consumption. In addition, it is possible to prevent inefficient use of radio resources allocated by the base station to uplink scheduling. In addition, by performing the transmission power control accurately, it is possible to increase the performance of uplink data transmission. Thus, the performance of the overall system can be improved.

1 is a block diagram illustrating a wireless communication system. This may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS). The E-UMTS system may be referred to as a Long Term Evolution (LTE) system. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

Referring to FIG. 1, an Evolved-UMTS Terrestrial Radio Access Network (E-UTRAN) includes a base station (BS) 20 that provides a control plane and a user plane.

The UE 10 may be fixed or mobile and may be called by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device, and the like. The base station 20 generally refers to a fixed station communicating with the terminal 10, and may be referred to as other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), and an access point. have. One base station 20 may provide a service for at least one cell. The cell is an area where the base station 20 provides a communication service. An interface for transmitting user traffic or control traffic may be used between the base stations 20. Hereinafter, downlink means communication from the base station 20 to the terminal 10, and uplink means communication from the terminal 10 to the base station 20.

The base stations 20 may be connected to each other through an X2 interface. The base station 20 is connected to an Evolved Packet Core (EPC), more specifically, a Mobility Management Entity (MME) / Serving Gateway (S-GW) 30 through an S1 interface. The S1 interface supports a many-to-many-relation between base station 20 and MME / S-GW 30.

2 is a block diagram illustrating a functional split between an E-UTRAN and an EPC. The hatched box represents the radio protocol layer and the white box represents the functional entity of the control plane.

Referring to FIG. 2, the base station performs the following function. (1) Radio Resource Management such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic Resource Allocation to UE RRM), (2) Internet Protocol (IP) header compression and encryption of user data streams, (3) routing of user plane data to S-GW, and (4) paging messages. Scheduling and transmission, (5) scheduling and transmission of broadcast information, and (6) measurement and measurement report setup for mobility and scheduling.

The MME performs the following functions. (1) Non-Access Stratum (NAS) signaling, (2) NAS signaling security, (3) Idle mode UE Reachability, (4) Tracking Area list management , (5) Roaming, (6) Authentication.

S-GW performs the following functions. (1) mobility anchoring, (2) lawful interception. P-GW (P-Gateway) performs the following functions. (1) terminal IP (allocation) allocation (allocation), (2) packet filtering.

3 is a block diagram illustrating elements of a terminal. The terminal 50 includes a processor 51, a memory 52, an RF unit 53, a display unit 54, and a user interface unit 55. . The processor 51 is implemented with layers of the air interface protocol to provide a control plane and a user plane. The functions of each layer may be implemented through the processor 51. The memory 52 is connected to the processor 51 to store a terminal driving system, an application, and a general file. The display unit 54 displays various information of the terminal, and may use well-known elements such as liquid crystal display (LCD) and organic light emitting diodes (OLED). The user interface unit 55 may be a combination of a well-known user interface such as a keypad or a touch screen. The RF unit 53 is connected to a processor and transmits and / or receives a radio signal.

The layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) model, which is well known in a communication system. It may be divided into a second layer L2 and a third layer L3. Among them, the physical layer belonging to the first layer provides an information transfer service using a physical channel, and is a radio resource control (RRC) layer located in the third layer. The role of controlling the radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the UE and the network.

4 is a block diagram illustrating a radio protocol architecture for a user plane. 5 is a block diagram illustrating a radio protocol structure for a control plane. This shows the structure of the air interface protocol between the terminal and the E-UTRAN. The user plane is a protocol stack for user data transmission, and the control plane is a protocol stack for control signal transmission.

4 and 5, a physical layer (PHY), which is a first layer, provides an information transfer service to a higher layer using a physical channel. The physical layer is connected to the upper Media Access Control (MAC) layer through a transport channel, and data between the MAC layer and the physical layer moves through this transport channel. Data moves between physical layers between physical layers, that is, between physical layers of a transmitting side and a receiving side.

The MAC layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. In the RLC layer, there are three operation modes according to a data transmission method: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). The AM RLC provides a bidirectional data transmission service, and supports retransmission when an RLC Protocol Data Unit (PDU) fails to transmit.

The Packet Data Convergence Protocol (PDCP) layer of the second layer performs a header compression function to reduce the IP packet header size.

The radio resource control (RRC) layer of the third layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transport channels, and physical channels in connection with configuration, re-configuration, and release of radio bearers (hereinafter, RBs). RB means a service provided by the second layer for data transmission between the UE and the E-UTRAN. If there is an RRC connection (RRC Connection) between the RRC of the terminal and the RRC of the network, the terminal is in the RRC Connected Mode, otherwise it is in the RRC Idle Mode.

The non-access stratum (NAS) layer located above the RRC layer performs functions such as session management and mobility management.

6 illustrates mapping between a downlink logical channel and a downlink transport channel. This includes 3GPP TS 36.300 V8.3.0 (2007-12) Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; See section 6.1.3.2 of Stage 2 (Release 8).

Referring to FIG. 6, a paging control channel (PCCH) is mapped to a paging channel (PCH), and a broadcast control channel (BCCH) is mapped to a broadcast channel (BCH) or a downlink shared channel (DL-SCH). Common Control Channel (CCCH), Dedicated Control Channel (DCCH), Dedicated Traffic Channel (DTCH), Multicast Control Channel (MCCH) and Multicast Traffic Channel (MTCH) are mapped to DL-SCH. MCCH and MTCH are also mapped to MCH (Multicast Channel).

Each logical channel type is defined by what kind of information is transmitted. There are two types of logical channels: control channels and traffic channels.

The control channel is used for transmission of control plane information. BCCH is a downlink channel for broadcasting system control information. PCCH is a downlink channel that transmits paging information and is used when the network does not know the location of the terminal. CCCH is a channel for transmitting control information between the terminal and the network, and is used when the terminal does not have an RRC connection with the network. The MCCH is a point-to-multipoint downlink channel used for transmitting multimedia broadcast multicast service (MBMS) control information and is used for terminals receiving MBMS. DCCH is a point-to-point unidirectional channel for transmitting dedicated control information between the terminal and the network, and is used by a terminal having an RRC connection.

The traffic channel is used for transmission of user plane information. DTCH is a point-to-point channel for transmitting user information and exists in both uplink and downlink. MTCH is a point-to-many downlink channel for transmission of traffic data, and is used for a terminal receiving an MBMS.

Transport channels are classified according to how and with what characteristics data is transmitted over the air interface. The BCH has a predefined transmission format that is broadcast and fixed in the entire cell area. The DL-SCH supports hybrid automatic repeat request (HARQ), dynamic link adaptation by changing modulation, coding and transmission power, possibility of broadcasting, possibility of beamforming, and dynamic / semi-static resources. It is characterized by allocation support, discontinuous reception (DRX) support for UE power saving, and MBMS transmission support. PCH is characterized by DRX support for terminal power saving and broadcast to the entire cell area. The MCH is characterized by broadcast to the entire cell area and MBMSN (MBMS Single Frequency Network) support.

7 shows mapping between a downlink transport channel and a downlink physical channel. This may be referred to Section 5.3.1 of 3GPP TS 36.300 V8.3.0 (2007-12).

Referring to FIG. 7, a BCH is mapped to a physical broadcast channel (PBCH), an MCH is mapped to a physical multicast channel (PMCH), and a PCH and DL-SCH are mapped to a physical downlink shared channel (PDSCH). PBCH carries the BCH transport block, PMCH carries the MCH, and PDSCH carries the DL-SCH and PCH.

There are several downlink physical control channels used in the physical layer. The physical downlink control channel (PDCCH) informs the UE about resource allocation of the PCH and DL-SCH and HARQ information related to the DL-SCH. The PDCCH may carry an uplink scheduling grant informing the UE of resource allocation of uplink transmission. The physical control format indicator channel (PCFICH) informs the UE of the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols used for transmission of PDCCHs in a subframe. PCFICH is transmitted every subframe. PHICH (physical Hybrid ARQ Indicator Channel) carries a HARQ ACK / NAK signal in response to uplink transmission.

8 shows the structure of a radio frame.

Referring to FIG. 8, a radio frame consists of 10 subframes, and one subframe consists of two slots. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms.

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

9 is an exemplary diagram illustrating a resource grid for one downlink slot.

Referring to FIG. 9, the downlink slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in a time domain. Here, one downlink slot includes 7 OFDM symbols and one resource block includes 12 subcarriers in a frequency domain as an example, but is not limited thereto.

Each element on the resource grid is called a resource element, and one resource block includes 12 × 7 resource elements. The number N ^DL of resource blocks included in the downlink slot depends on the downlink transmission bandwidth set in the cell.

10 shows the structure of a subframe.

Referring to FIG. 10, a subframe includes two consecutive slots. The maximum 3 OFDM symbols of the first slot in the subframe are the control region to which the PDCCH is allocated, and the remaining OFDM symbols are the data region to which the PDSCH is allocated. The UE may read the data information transmitted through the PDSCH by decoding the control information transmitted through the PDCCH. Here, it is merely an example that the control region includes 3 OFDM symbols. The number of OFDM symbols included in the control region in the subframe can be known through the PCFICH.

11 is a flowchart illustrating an example of an uplink scheduling method.

Referring to FIG. 11, the base station transmits an uplink grant to the terminal (S10). The terminal transmits uplink data through a PUSCH (Physical Uplink Shared Channel) to the base station according to the uplink grant (S11).

The uplink grant is uplink scheduling information. The uplink grant may be transmitted through the PDCCH. The uplink grant may include radio resource allocation information of a PUSCH, a transmit power control (TPC) command, a redundancy version (RV), a new data indicator (NDI), and the like.

TPC is a technique for solving the perspective problem caused by transmitting the signal by the terminals are distributed near or far from the base station. If it is assumed that all terminals transmit signals with the same power, a signal transmitted by a terminal located near the base station is received much larger than a signal transmitted by a terminal located far away. Therefore, the terminal located near there is no problem in the call, but the terminal located far away will experience a relatively very large interference. Therefore, the TPC is a technique for adjusting the transmission power of each terminal so that the base station receives the signal with the same size. TPCs include open loop TPC and closed loop TPC. The open loop TPC is not a loop for transmitting and receiving signals and control between the terminal and the base station. Instead, the transmission subject arbitrarily adjusts the transmission power. The closed loop TPC uses feedback information for power control. A base station and a terminal interwork with each other to adjust transmission power.

The TPC command may indicate one of [-1, 0, 1, 3] dB (decibel). In this case, the TPC command may be 2 bits. The terminal controls the transmit power of the PUSCH by using a TPC command. For example, if the TPC command is '0b11' indicating 3 dB, the UE may accumulate 3 dB in the transmit power of the PUSCH.

The sequence of redundancy versions is defined as 0, 2, 3, 1. The redundancy version is transmitted in the order of 0, 2, 3, 1, 0, 2, 3, 1 if the maximum number of the hybrid automatic repeat (HARQ) process is 8.

The new data indicator indicates whether this is a new Hybrid Automatic Repeat reQuest (HARQ) transmission. The base station toggles a new data indicator whenever the HARQ transmission of the corresponding process ID is completed. The UE may know whether the HARQ transmission is a new transmission or a retransmission through the new data indicator.

The base station attempts to decode uplink data. If no error is detected in the cyclic redundancy check (CRC) of the uplink data, the uplink data is successfully decoded. If uplink data is successfully decoded, the base station transmits an acknowledgment (ACK) to the terminal.

If an error is detected in the CRC of the uplink data, the base station transmits a negative acknowledgment (NACK) to the terminal (S12). The terminal may receive an ACK or a NACK through the PHICH. For example, when the UE receives the ACK or NACK in the i-th subframe, the UE may determine that the UE is an ACK or NACK for the PUSCH transmitted in the i-4th subframe. Upon receiving the NACK, the terminal retransmits uplink data through the PUSCH to the base station (S13).

12 is a flowchart illustrating another example of an uplink scheduling method.

12, the base station transmits an uplink grant to the terminal (S20). It is assumed that the uplink grant is lost during transmission, so that the terminal does not receive the uplink grant. Since the UE has not received the uplink grant, the UE cannot transmit the uplink data through the PUSCH.

The base station waits for reception of uplink data through the PUSCH, but does not detect the PUSCH (No Detection, S21). The base station determines that the uplink data is lost, and transmits a NACK requesting retransmission of the uplink data to the terminal (S22). However, since the terminal has not received the uplink grant, the terminal cannot transmit the uplink data.

11 illustrates a case in which a terminal receives an uplink grant and a base station receives uplink data, but an error is detected in the uplink data. In contrast, FIG. 12 illustrates a case in which the terminal does not receive the uplink grant and the base station does not receive the uplink data. Thus, FIG. 11 and FIG. 12 are different cases. However, in the case of FIG. 12, when the base station transmits a NACK to the terminal as shown in FIG. 11, data transmission and reception are delayed and a problem of wasting limited radio resources occurs. In particular, the PUSCH radio resources allocated in the uplink grant are wasted. Accordingly, there is a need for a method of receiving uplink data to solve this problem when the base station does not detect the PUSCH.

13 is a flowchart illustrating an example of an uplink scheduling method according to an embodiment of the present invention.

Referring to FIG. 13, the base station transmits an uplink grant to the terminal (S100). The base station does not detect the PUSCH in the radio resources allocated through the uplink grant (S110). The base station determines that the terminal has not received the uplink grant. The case where the base station does not detect the PUSCH is called a PUSCH loss.

The base station retransmits the uplink grant to the terminal (S120). The uplink grant being retransmitted is for the same terminal as the uplink grant previously transmitted, but does not need to include the same radio resource allocation information as the uplink grant previously transmitted.

The terminal transmits uplink data through the PUSCH to the base station (S130). The base station transmits ACK or NACK according to whether the error of uplink data is detected (S140).

If the base station does not detect the PUSCH after transmitting the NACK more than once to the terminal, the base station may not retransmit the uplink grant to the terminal.

However, when the base station does not detect the PUSCH and retransmits the uplink grant, there is a need for a method for processing uplink grant information such as a TPC command, redundancy version information, and a new data indicator.

14 shows an example of an uplink scheduling method when no PUSCH loss occurs.

Referring to FIG. 14, the base station uses a TPC update window. The TPC update window is defined as a period in which the base station determines the TPC using the received power of the PUSCH. Rather than calculating the TPC every TTI, it is more efficient to calculate the TPC during the TPC update window, which is a plurality of TTI intervals, because of less system overhead. The base station calculates the TPC by measuring the power of the received PUSCH within the previous TPC update window. For example, the base station can determine the TPC by obtaining a power average of the PUSCHs received in the TPC update window.

Assume that the TPC determined in the previous TPC update window is three. The base station sets the TPC command included in the first uplink grant (UL grant 1) transmitted first in the TPC update window to '3' (S200). In addition, it is assumed that the redundancy version information included in the first uplink grant is set to '0' and the new data indicator is set to '0'. The base station transmits a second uplink grant (UL grant 2) in the TPC update window (S205). Since the previously determined TPC update is fully reflected in the first uplink grant, the base station sets the TPC command to '0' from the second uplink grant in the TPC update window. The base station transmits a first ACK (ACK 1) to the received uplink data according to the first uplink (S210). The base station transmits a third uplink grant (UL grant 3) (S215). The base station transmits a second NACK (NACK 2) for the uplink data received according to the second uplink (S220).

The base station transmits a fourth uplink grant (UL grant 4) (S225). At this time, the new data indicator is toggled to '1'. The base station transmits a third ACK (ACK 3) (S230). The base station does not transmit the uplink grant while receiving uplink data according to the second uplink grant. The base station transmits a fourth NACK (NACK 4) (S235). The base station transmits a fifth uplink grant (UL grant 5) (S240). The base station transmits a second ACK (ACK 2) (S245).

The base station does not transmit the uplink grant while receiving uplink data according to the fourth uplink grant. The base station transmits a fifth ACK (ACK 5) (S250). The base station transmits a sixth uplink grant (UL grant 6) (S255). The base station transmits a fourth ACK (ACK 4) (S260). The base station transmits a seventh uplink grant (UL grant 7) (S265). At this time, the new data indicator is toggled to '0'. The base station transmits a sixth ACK (ACK 6) (S270).

The base station receives the PUSCH according to each uplink grant during the TPC update window period in which the first uplink grant and the seventh uplink grant are transmitted. The base station determines the TPC by measuring the received power of the PUSCH received during the TPC update window period, and sets the TPC command reflecting the determined TPC in the first uplink grant transmitted in the next TPC update window period. In the next TPC update window period, the base station transmits a seventh NACK (NACK 7) (S275).

15 shows another example of an uplink scheduling method when no PUSCH loss occurs.

Referring to FIG. 15, it is assumed that the TPC determined in the previous TPC update window is 7. The TPC command included in the uplink grant may be 2 bits, and the TPC command may indicate one of [-1, 0, 1, 3] dB. That is, when the determined TPC is larger than 3, the maximum value of the TPC command, it cannot be reflected in the first uplink grant transmitted first in the TPC update window. Thus, the base station reflects the TPC determined using the uplink grant following the first uplink grant.

The base station sets the TPC command included in the first uplink grant (UL grant 1) to '3', sets the TPC command included in the second uplink grant (UL grant 2) to '3', and the third uplink grant Set the TPC command included in (UL grant 3) to '1'. In this way, since all of the previously determined TPC update TPC is reflected in the first uplink grant, the base station sets the TPC command to '0' from the fourth uplink grant in the TPC update window. It is the same as the uplink grant information processing method of FIG. 14 except for a method of reflecting the TPC determined in the previous TPC update window.

16 shows an example of an uplink scheduling method when a PUSCH loss occurs.

Referring to FIG. 16, it is assumed that a TPC determined in a previous TPC update window is 3. The base station transmits a first uplink grant (UL grant 1) in which the TPC command is set to '3' in the TPC update window (S300). The base station transmits a second uplink grant (UL grant 2) in which the TPC command is set to '0' (S305). The base station waits for reception of uplink data through the PUSCH according to the first uplink grant, but the PUSCH is not detected. That is, a PUSCH loss occurs (S310). The base station transmits a third uplink grant (UL grant 3) (S315). The base station transmits a second NACK (NACK 2) (S320).

The base station retransmits the first uplink grant in the TPC update window (S325). The TPC command is set to '3' like the first uplink grant previously transmitted. As with the first uplink previously transmitted, the redundancy version information may be set to '0' and the new data indicator may be set to '0'. The redundancy version can have other values.

The base station retransmits the uplink grant because the base station determines that the terminal has not properly received the uplink grant. If the UE properly receives the uplink grant and transmits the uplink data through the PUSCH, it may be recognized by the base station as a PUSCH loss. In this case, if the TPC command of the previously transmitted uplink is already reflected, the terminal does not reflect the TPC command of the retransmitted uplink grant again.

The base station transmits a third ACK (ACK 3) (S330). The base station does not transmit the uplink grant while receiving uplink data according to the second uplink grant. The base station transmits a first NACK (NACK 1) (S335). The base station transmits a fourth uplink grant (UL grant 4) (S340). At this time, the new data indicator is toggled to '1'. The base station transmits a second ACK (ACK 2) (S345).

The base station does not transmit the uplink grant while receiving uplink data according to the first uplink grant. The base station transmits a fourth ACK (ACK 4) (S350). The base station transmits a fifth uplink grant (UL grant 5) (S355). The base station transmits a first ACK (ACK 1) (S360). The base station transmits a sixth uplink grant (UL grant 6) (S365). At this time, the new data indicator is toggled to '0'. The base station transmits a fifth ACK (ACK 5) (S370).

The base station determines the TPC during the TPC update window period, and reflects the TPC in the next TPC update window period. In the next TPC update window period, the base station transmits a sixth NACK (NACK 6) (S375).

17 shows another example of an uplink scheduling method when a PUSCH loss occurs.

Referring to FIG. 17, it is assumed that a TPC determined in a previous TPC update window is 7. The base station transmits a first uplink grant (UL grant 1) in which the TPC command is set to '3' in the TPC update window (S400). The base station transmits a second uplink grant (UL grant 2) in which the TPC command is set to '3' (S405).

Although the base station waits for reception of uplink data through the PUSCH according to the first uplink grant, a PUSCH loss occurs (S410). The base station transmits a third uplink grant (UL grant 3) in which the TPC command is set to '1' (S415). The base station transmits a second NACK (NACK 2) (S420).

The base station retransmits the first uplink grant in the TPC update window (S425). The TPC command is set to '3' like the first uplink grant previously transmitted. As with the first uplink previously transmitted, the redundancy version information may be set to '0' and the new data indicator may be set to '0'. In the base station, a PUSCH loss occurs according to the second uplink grant (S430). The base station does not transmit the uplink grant while receiving uplink data according to the second uplink grant. The base station transmits a first NACK (NACK 1) (S435). The base station retransmits the third uplink grant in the TPC update window (S440). The TPC command is set to '0' like the third uplink grant previously transmitted. The base station transmits a second ACK (ACK 2) (S445).

The base station does not transmit the uplink grant while receiving uplink data according to the first uplink grant. The base station transmits a third ACK (ACK 3) (S450). The base station transmits a fourth uplink grant (UL grant 4) (S455). At this time, the new data indicator is toggled to '1'. The base station transmits a first ACK (ACK 1) (S460). The base station transmits a fifth uplink grant (UL grant 5) (S465). The base station transmits a fourth ACK (ACK 4) (S470).

The base station determines the TPC during the TPC update window period, and reflects the TPC in the next TPC update window period. In the next TPC update window period, the base station transmits a fifth NACK (NACK 5) (S475).

18 shows another example of an uplink scheduling method when a PUSCH loss occurs. FIG. 18 illustrates an example in which retransmission of an uplink grant exceeds a TPC update window unlike in FIGS. 16 and 17.

Referring to FIG. 18, it is assumed that a TPC determined in the TPC update window is 3. The base station transmits a first uplink grant (UL grant 1) in which the TPC command is set to '3' in the TPC update window (S500). In addition, it is assumed that the redundancy version information included in the first uplink grant is set to '0' and the new data indicator is set to '0'. The base station transmits a second uplink grant (UL grant 2) (S505). Although the base station waits for reception of uplink data through the PUSCH according to the first uplink grant, a PUSCH loss occurs (S510). The base station transmits a third uplink grant (UL grant 3) (S515). The base station transmits a second NACK (NACK 2) (S520).

The base station determines the TPC during the TPC update window period. Assume that the TPC determined during the TPC update universe window is one.

The first uplink grant is retransmitted in the next TPC update window (S525). The retransmitted first uplink grant has a TPC command set to '1' unlike the first uplink grant transmitted in the TPC update window period. The redundancy version information and the new data indicator of the first uplink grant retransmitted are the same as the first uplink grant transmitted in the TPC update window period. The base station transmits a third ACK (ACK 3) (S530). The base station transmits a first NACK (NACK 1) (S535).

In this way, the base station can quickly process the uplink data loss, it is possible to prevent the delay of data processing between the base station and the terminal. This can reduce power consumption. In addition, it is possible to prevent inefficient use of radio resources allocated by the base station to uplink scheduling. In addition, by performing the transmission power control accurately, it is possible to increase the performance of uplink data transmission. Thus, the performance of the overall system can be improved.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

1 is a block diagram illustrating a wireless communication system.

2 is a block diagram illustrating functional division between an E-UTRAN and an EPC.

3 is a block diagram illustrating elements of a terminal.

4 is a block diagram illustrating a radio protocol structure for a user plane.

5 is a block diagram illustrating a radio protocol structure for a control plane.

6 shows a mapping between a downlink logical channel and a downlink transport channel.

7 shows mapping between a downlink transport channel and a downlink physical channel.

8 shows the structure of a radio frame.

9 is an exemplary diagram illustrating a resource grid for one downlink slot.

10 shows the structure of a subframe.

11 is a flowchart illustrating an example of an uplink scheduling method.

12 is a flowchart illustrating another example of an uplink scheduling method.

13 is a flowchart illustrating an example of an uplink scheduling method according to an embodiment of the present invention.

14 shows an example of an uplink scheduling method when no PUSCH loss occurs.

15 shows another example of an uplink scheduling method when no PUSCH loss occurs.

16 shows an example of an uplink scheduling method when a PUSCH loss occurs.

17 shows another example of an uplink scheduling method when a PUSCH loss occurs.

18 shows another example of an uplink scheduling method when a PUSCH loss occurs.

Claims (14)

In the uplink scheduling method in a wireless communication system, Transmitting an uplink grant which is uplink scheduling information; And And if the uplink data according to the uplink is not received, retransmitting the uplink grant. The method of claim 1, The uplink scheduling information is scheduling information of a physical uplink shared channel (PUSCH). The method of claim 1, The uplink grant is transmitted through the physical downlink control channel (PDCCH). The method of claim 1, The uplink grant includes a first transmit power control command for controlling the transmit power of the uplink data, The first transmission power control command reflects a first correction value determined using the reception power of uplink data received in the first update window. And the uplink grant is transmitted in a second update window that is a subsequent update window of the first update window. The method of claim 4, wherein If the maximum value that can be indicated by the first transmission power control command does not reflect all of the first correction value, the remainder that is not reflected is reflected in the transmission power control command of an uplink grant transmitted subsequent to the uplink grant. Uplink scheduling method. The method of claim 4, wherein And when the uplink grant is retransmitted within the second update window, a second transmit power control command included in the retransmitted uplink grant is the same as the first transmit power control command. The method of claim 4, wherein When the uplink grant is retransmitted in a third update window that is a subsequent update window of the second update window, the third transmit power control command included in the retransmitted uplink grant is an uplink received in the second update window. Uplink scheduling method, characterized in that for reflecting the second correction value determined using the received power of the data. In the uplink scheduling method in a wireless communication system, Transmitting an uplink grant which is uplink scheduling information; And Retransmitting the uplink grant, if uplink data according to the uplink grant is not received, The uplink grant includes a first transmit power control command for controlling the transmit power of the uplink data, The first transmission power control command reflects a first correction value determined using the reception power of uplink data received in the first update window. And the uplink grant is transmitted in a second update window that is a subsequent update window of the first update window. The method of claim 8, The uplink scheduling information is scheduling information of a PUSCH. The method of claim 8, The uplink grant is transmitted on the PDCCH, characterized in that uplink scheduling method. The method of claim 8, The uplink grant includes a first transmit power control command for controlling the transmit power of the uplink data, The first transmission power control command reflects a first correction value determined using the reception power of uplink data received in the first update window. And the uplink grant is transmitted in a second update window that is a subsequent update window of the first update window. The method of claim 8, If the maximum value that can be indicated by the first transmission power control command does not reflect all of the first correction value, uplink scheduling characterized in that the remainder that is not reflected is reflected in an uplink grant transmitted after the uplink grant. Way. The method of claim 8, And when the uplink grant is retransmitted within the second update window, a second transmit power control command included in the retransmitted uplink grant is the same as the first transmit power control command. The method of claim 8, When the uplink grant is retransmitted in a third update window that is a subsequent update window of the second update window, the third transmit power control command included in the retransmitted uplink grant is an uplink received in the second update window. Uplink scheduling method, characterized in that for reflecting the second correction value determined using the received power of the data.

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