KR101827555B1

KR101827555B1 - Method and device for uplink buffer status management

Info

Publication number: KR101827555B1
Application number: KR1020150057307A
Authority: KR
Inventors: 김대익; 김경숙; 김성경; 나지현
Original assignee: 한국전자통신연구원
Priority date: 2015-04-23
Filing date: 2015-04-23
Publication date: 2018-03-22
Also published as: KR20160126346A

Abstract

A method of managing an uplink buffer state of a base station according to various embodiments of the present invention includes receiving a buffer status report from a terminal, setting a data amount of the buffer indicated by the buffer status report to a current data amount of the buffer Allocating uplink resources to the UE, and correcting the current data amount of the buffer by subtracting the allocated resource amount from the current data amount of the buffer.

Description

[0001] The present invention relates to an uplink buffer state management method,

The present invention relates to a method of managing an uplink buffer state in a cellular mobile communication system.

In a mobile communication system, a buffer for transmitting uplink data unlike a downlink exists in a UE. A BS allocates uplink resources to a buffer status report (BSR) to inform how much data is accumulated in the current buffer. medium access control (CE) is used to inform the current buffer size, and the base station allocates uplink resources based on the state.

Since the BSR has a large overhead to report the actual buffer size for all logical channels (LCs) of the UE, the BSR has a problem in that the logical channel group (LCG) Transmits the buffer size level, and the base station estimates the buffer size of the LCG based on the total buffer size level of the LCG.

Due to the LCG allocation and BSR reporting characteristics of the LC described above, the base station can not know how much buffer size exists in the actual LC, and allocates resources based on the buffer size of the LCG. Also, even though the BS allocates the uplink resources based on the buffer size of the LCG, the uplink grant (UL Grant) to the UE includes only the resource amount information allocated to the UE, not the resource information allocated per LCG, The UE determines the amount of data to be transmitted per LC by considering the priority for each LC. Accordingly, inconsistency may occur in buffer size information between the base station and the terminal. For example, when the buffer size of the terminal is 100 bytes, 50 bytes, 300 bytes, and 1000 bytes per LCG, the base station allocates a total of 300 bytes of resources through the uplink grant and allocates 100 bytes, 50 bytes, 100 bytes, and 50 bytes, respectively. However, the terminal can allocate resources of 50 bytes, 50 bytes, 50 bytes, and 150 bytes for each LCG. The resources required for the UE may not be appropriately allocated due to buffer size mismatch between the BS and the UE.

Also, if uplink acknowledgment is additionally performed due to a buffer size mismatch resulting from receiving the BSR transmitted by the UE after the UE continuously determines the BSR and after the UE has determined the BSR, There is no data to be transmitted to the terminal, so that empty data can be transmitted. This waste of uplink resources may degrade the overall performance of the mobile communication system.

In various embodiments of the present invention, a base station sets a data amount of a buffer for each LCG based on a resource amount allocated to each terminal by a carrier component (CC), and based on the amount of actually received data or the allocated resource amount, And correcting the data amount of the base station and the terminal to thereby match the buffer status information between the base station and the terminal.

A method of managing an uplink buffer state of a base station according to various embodiments of the present invention includes receiving a buffer status report from a terminal, calculating a data amount of the buffer indicated by the buffer status report, A step of allocating an uplink resource to the terminal, and a step of correcting a current data amount of the buffer by subtracting the allocated resource amount from the current data amount of the buffer.

According to an exemplary embodiment, the method may further include correcting a current data amount of the buffer by subtracting a resource amount allocated after a time point at which the new buffer status report is generated from the current data amount of the buffer .

According to one embodiment, the method includes receiving uplink data from a terminal, calculating a received data amount, calculating a difference between the amount of resource allocated to the received data and the amount of received data And correcting the current data amount of the buffer using the difference between the allocated resource amount and the received data amount.

According to an embodiment, the step of correcting the current data amount of the buffer using the difference between the allocated resource amount and the received data amount may further include: if the allocated resource amount is greater than the received data amount, And decreasing the current data amount of the buffer by the difference if the allocated resource amount is less than the received data amount.

According to one embodiment, the buffer status report includes an index indicating a data amount of a buffer for at least one logical channel group, and the step of correcting the current data amount of the buffer includes: The amount can be corrected.

According to one embodiment, the method comprises the steps of: determining whether data to be allocated is a second transmission or a retransmission; and if the data is a retransmission, adding a resource amount previously allocated to the data to the current data amount of the buffer, And correcting the current data amount of the buffer.

The base station according to various embodiments of the present invention sets the data amount of the buffer indicated by the buffer status report to the current data amount of the buffer when a buffer status report is received from the communication unit and the terminal communicating with the terminal And a controller for allocating an uplink resource to the terminal and correcting the current data amount of the buffer by subtracting the allocated resource amount from the current data amount of the buffer.

According to an embodiment, the control unit may correct the current data amount of the buffer by subtracting the amount of resources allocated after the generation of the buffer status report from the current data amount of the buffer.

According to one embodiment, the control unit calculates the amount of received data when the uplink data is received from the terminal, and calculates the current amount of data of the buffer using the difference between the amount of resource allocated to the received data and the amount of received data. The data amount can be corrected.

According to one embodiment, the control unit increases the current data amount of the buffer by the difference if the allocated resource amount is larger than the received data amount, and if the allocated resource amount is smaller than the received data amount, Can be reduced by the difference.

According to an embodiment, the buffer status report includes an index indicating a data amount of a buffer for at least one logical channel group, and the controller can correct the current data amount of the buffer for each logical channel group.

According to one embodiment, the control unit determines whether the data to be allocated is a second transmission or a retransmission, and if the data is a retransmission, adds the amount of resources previously allocated to the data to the current data amount of the buffer, It is possible to correct the current data amount of the data.

According to various embodiments of the present invention, buffer status information between a base station and a terminal is matched by correcting a current data amount of a buffer based on a resource amount allocated by a base station, a buffer status report received from a terminal, and uplink data in a mobile communication system Maximize the use of uplink resources, and provide enhanced services to users.

1 shows an example of an LCG allocation according to an embodiment of the present invention.
2 and 3 are diagrams illustrating a BSR format according to an embodiment of the present invention.
4 is a conceptual diagram illustrating transmission of uplink data in a carrier aggregation environment according to an embodiment of the present invention.
5 is a diagram illustrating a method of managing an uplink buffer state in a mobile communication system according to an embodiment of the present invention.
6 is a flowchart illustrating a method by which a base station corrects a data amount of a buffer according to an embodiment of the present invention.
7 is a flowchart illustrating a method by which a base station corrects a data amount of a buffer according to an embodiment of the present invention.
8 is a flowchart illustrating a method for a base station to correct a data amount of a buffer according to an embodiment of the present invention.
9 shows a wireless interface protocol structure according to an embodiment of the present invention.
10 is a block diagram illustrating a configuration of a base station according to an embodiment of the present invention.

The wireless communication system according to various embodiments of the present invention may include at least one base station 200 (BS). Each base station 200 provides communication services for specific cells (15a, 15b, 15c). A cell can be divided into multiple regions (or sectors).

A mobile station (MS) 100 may be fixed or mobile and may be a user equipment (UE), a mobileeterminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a PDA a personal digital assistant, a wireless modem, a handheld device, and the like. The base station 200 may be referred to as another term such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, a femto base station, a home node B, . The cell should be interpreted in a generic sense to denote a partial region covered by the base station 200, and may be meant to encompass various coverage areas such as a megacell, a macrocell, a microcell, a picocell, and a femtocell.

The downlink means communication from the base station 200 to the terminal 100 and the uplink means communication from the terminal 100 to the base station 200. In the downlink, the transmitter may be a part of the base station 200, and the receiver may be a part of the terminal 100. In the uplink, the transmitter may be part of the terminal 100, and the receiver may be part of the base station 200. There are no restrictions on multiple access schemes applied to wireless communication systems. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier FDMA (SC-FDMA), OFDM- Various multiple access schemes such as OFDM-CDMA can be used. A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

A carrier aggregation (CA) supports a plurality of carriers and is also referred to as spectrum aggregation or bandwidth aggregation. The individual unit carriers tied by carrier aggregation are called component carriers (CCs). Each element carrier can be defined as a bandwidth and a center frequency. For example, if five elementary carriers are allocated as the granularity of a carrier unit having a bandwidth of 20 MHz, it can support a bandwidth of up to 100 MHz.

1 shows an example of an LCG allocation according to an embodiment of the present invention.

Referring to FIG. 1, a logical channel group (LCG) may include at least one logical channel (LC). According to one embodiment, the logical channel group may be composed of a total of four (e.g., LCG # 0 to LCG # 3). Signaling radio bearers (SRB) 1 and 2 may be assigned to LCG # 0. The priority of the signal radio bearers may be 1 and 3, respectively. The prioritized bit rate (PBR) of the signal radio bearer can be infinite. The added data radio bearer (DRB) may then have a value of 3 to 10 and may be assigned to one of logical channel groups 0 to 3. Each LC may have one of the priorities 1-16. Each LC may have one of PBR 0-2048 kBps. Each LC may have one of a bucket size duration (BSD) of 50 to 1000 ms. The UE may transmit a buffer status report (BSR) indicating the buffer sum of the LCs belonging to the allocated LCG to the BS.

2 and 3 are diagrams illustrating a BSR format according to an embodiment of the present invention. Figure 2 shows a Short or Truncated BSR format, and Figure 3 shows a Long BSR format.

The UE can transmit the BSR to the BS in the empty buffer, for example, data arrival time, high priority data arrival time, periodic BSR transmission time, BSR retransmission time, and the like. The UE can transmit the BSR when the padding size of the MAC PDU (Packet Data Unit) to be transmitted to the allocated uplink resource is larger than the size including the BSR MAC CE and the MAC header. Long BSR can report BSR for all LCGs. Short BSRs can only transmit BSRs for one LCG. The truncated BSR can be used to report the BSR for the LCG having the highest priority when the size is not enough to transmit the Long BSR to the MAC PDU at the time of transmitting the Long BSR. The terminal may transmit an index of 6 bits indicating the buffer size level to the base station for LCG, and refer to 3GPP TS 36.321 for buffer size mapping to the buffer size level.

4 is a conceptual diagram illustrating transmission of uplink data in a carrier aggregation environment according to an embodiment of the present invention.

Referring to FIG. 4, a base station can aggregate a plurality of carrier components (CCs) to provide a high data rate to a terminal. In a carrier aggregation (CA) environment, terminals can communicate only by connecting to one CC or aggregate a plurality of CCs to transmit uplink data to the base station. Even when a terminal aggregates a plurality of CCs and communicates with a base station, uplink resources may be allocated to only one CC at a certain moment, or uplink resources may be allocated to all CCs. According to an exemplary embodiment, a terminal may transmit data for a resource-allocated CC and may also transmit a BSR.

5 is a diagram illustrating a method of managing an uplink buffer state in a mobile communication system according to an embodiment of the present invention.

In FIG. 5, for convenience of explanation, the carrier collecting environment is shown as PHY (CC0, CC1), CC0 is assumed as PCell (primary cell), and CC1 is assumed as SCell (secondary cell).

When data is received in a buffer for uplink data transmission in a state where a buffer is empty, a user equipment (UE) 100 transmits a scheduling request (SR) for transmitting a BSR MAC CE through a CC0 (S501). The CC0 PHY 201 of the base station 200 can inform the UL Scheduler 205 when a scheduling request is received (S503). Upon receiving the scheduling request, the uplink scheduler 205 allocates a resource capable of transmitting the BSR and instructs the CC0 PHY 201 to transmit UL grant in SFN / SF = n (S505). Here, SFN is a system frame number of 10ms unit, SF is a subframe number of 1ms unit, SFN / SF can be expressed by the sum of SFN and SF.

The CC0 PHY 201 may generate downlink data during the downlink processing time and transmit the uplink grant from the SFN / SF = n to the terminal 100 (S507). After receiving the uplink grant, the subscriber station 100 may transmit the BSR to the base station 200 through a physical uplink shared channel (PUSCH) of CC0 after 4 subframes (S509). When the BSR is received, the CC0 PHY 201 of the base station 200 decodes the data during the uplink processing period and includes information on the SFN / SF time (i.e., SFN / SF = n + 4) The MAC PDU can be transmitted to the MAC 203 through an uplink shared channel (ULSCH) (S511). Here, the downlink processing time and the uplink processing time may be different depending on the processing performance of the PHY, and generally, a few subframes may be required.

The MAC 203 demultiplexes the MAC PDU when the MAC PDU is received and transmits the received time information SFN / SF = n + 4 to the UL scheduler 205 ). The uplink scheduler 205 can set the current data amount of the buffer for each LCG according to the buffer size level of the BSR when the BSR is received. The uplink scheduler 205 allocates the uplink resource to the CC0 according to the scheduling algorithm, and may correct the data amount of the buffer according to the allocated resource amount (S515). For example, the uplink scheduler 205 may correct the current data amount of the buffer by subtracting the allocated resource amount from the current data amount of the LCG-specific buffer. The uplink scheduler 205 may instruct the CC0 PHY 201 to transmit the uplink grant in the SFN / SF = m when the uplink resource is allocated (S517). The CC0 PHY 201 may transmit the uplink grant to the UE 100 in SFN / SF = m (S519).

The uplink scheduler 205 allocates the uplink resource to the CC1 according to the amount of data of the corrected buffer, and may correct the data amount of the buffer according to the allocated resource amount (S521). The uplink scheduler 205 may instruct the CC1 PHY 202 to transmit the uplink grant in the SFN / SF = m + 1 when the uplink resource is allocated (S523). The CC1 PHY 202 may transmit the uplink grant to the UE 100 in SFN / SF = m + 1 (S525).

The uplink scheduler 205 may allocate uplink resources to CC0 and CC1 according to the amount of data of the corrected buffer, and may correct the data amount of the buffer according to the allocated resource amount (S527). The uplink scheduler 205 may instruct the CC0 PHY 201 and the CC1 PHY 202 to transmit the uplink grant in the SFN / SF = m + 2, respectively, when the uplink resources are allocated (S529). The CC0 PHY 201 and the CC1 PHY 202 may transmit the uplink grant to the UE 100 in SFN / SF = m + 2 (S531).

When the UE 100 receives the uplink grant in SFN / SF = m, the UE 100 can generate uplink data in consideration of the allocated resource and the current LC by considering the buffer size, priority, and delay. The UE 100 may transmit the uplink data from the SFN / SF = m + 4 to the base station 200 through the CC0 (S533). When the uplink data is received, the CC0 PHY 201 of the base station 200 can decode the received data during the uplink processing time. The CC0 PHY 201 may transmit information on the decoded MAC PDU and data reception time (SFN / SF = m + 4) to the MAC 203 (S535). The MAC 203 demultiplexes the received PDU and transmits a RLC (radio link control) PDU to the RLC. The amount of data received for each LC, the CC information for which the corresponding data is received, and the received time (SFN / SF = m + 4) information to the uplink scheduler 205 (S537). The uplink scheduler 205 may determine that a time point at which resources are allocated to the received data using the received time (SFN / SF = m + 4) information is SFN / SF = m. The uplink scheduler 205 may compare the resource amount (or the data amount) allocated in SFN / SF = m with the actually received data amount to determine a difference. For example, the uplink scheduler 205 can determine the difference between the amount of resources allocated per LCG in SFN / SF = m and the amount of data actually received for each LCG to which received LCs belong. The uplink scheduler 205 may correct the current data amount of the buffer for each LCG using the difference between the allocated resource amount and the received data amount (S539). For example, the uplink scheduler 205 may increase the current data amount of the buffer by the difference between the allocated resource amount and the received data amount if the allocated resource amount is larger than the received data amount. For example, the UL scheduler 205 may reduce the current data amount of the buffer by a difference between the allocated resource amount and the received data amount if the allocated resource amount is smaller than the received data amount.

The UE 100 may generate uplink data to be transmitted in SFN / SF = m + 5 when the uplink grant is received in SFN / SF = m + 1. When the uplink grant is received, the UE 100 may generate a BSR including information on a data amount to be transmitted in SFN / SF = m + 5 and a data amount of a buffer excluding data currently being transmitted. The UE 100 may transmit the uplink data and the BSR to the Node B 200 through the CC1 in SFN / SF = m + 5 (S541). The CC1 PHY 202 of the base station 200 can decode the received data during the uplink processing time. The CC1 PHY 202 may transmit information on the decoded MAC PDU and data reception time (SFN / SF = m + 5) to the MAC 203 (S543). The MAC 203 demultiplexes the received PDUs and transmits the received data amount, the BSR, the received CC information, and the received time (SFN / SF = m + 5) information to the uplink scheduler 205 (S545). When the BSR is received, the uplink scheduler 205 calculates a resource amount allocated to SFN / SF = m + 1 (i.e., SFN / SF = m + 1) Resource amount is excluded) to correct the current data amount of the buffer (S547).

The UE 100 can generate uplink data to be transmitted through CC0 and CC1 in SFN / SF = m + 6 when the uplink grant is received in SFN / SF = m + 2. When the UE 100 receives the uplink grant, the UE 100 may generate a BSR including information on data to be transmitted in SFN / SF = m + 6 and information on the amount of data in the buffer excluding data currently being transmitted. The MS 100 may transmit uplink data through CC0 in SFN / SF = m + 6, uplink data and BSR through the CC1 to the BS 200 (S549). The CC0 PHY 201 and the CC1 PHY 202 of the base station 200 can decode the data received during the uplink processing time when the uplink data is received. The CC0 PHY 201 and the CC1 PHY 202 may transmit information on the decoded MAC PDU and data reception time (SFN / SF = m + 6) to the MAC 203 (S551).

The MAC 203 demultiplexes PDUs received from the CC0 PHY 201 and outputs the amount of data received for each LC, the CC information on which the data is received, and the received time (SFN / SF = m + 6) (S553). The uplink scheduler 205 may determine that the time at which resources are allocated to the received data using the received time (SFN / SF = m + 6) information is SFN / SF = m + 2. The uplink scheduler 205 can determine the difference by comparing the resource amount (or the data amount) allocated in SFN / SF = m + 2 with the actually received data amount. The uplink scheduler 205 can correct the current data amount of the buffer for each LCG using the difference between the allocated resource amount and the received data amount (S555). For example, the uplink scheduler 205 may increase the current data amount of the buffer by the difference between the allocated resource amount and the received data amount if the allocated resource amount is larger than the received data amount. For example, the UL scheduler 205 may reduce the current data amount of the buffer by a difference between the allocated resource amount and the received data amount if the allocated resource amount is smaller than the received data amount.

The MAC 203 demultiplexes the PDU received from the CC1 PHY 202 to increase the amount of data received per LC, the BSR, the CC information on which the data is received, and the received time (SFN / SF = m + 5) To the link scheduler 205 (S557). When the BSR is received, the uplink scheduler 205 may correct the current data amount of the buffer by subtracting the resource amount allocated after SFN = SF + m + 2 generated by the BSR from the data amount of the buffer indicated by the received BSR (S559).

6 is a flowchart illustrating a method by which a base station corrects a data amount of a buffer according to an embodiment of the present invention.

Referring to FIG. 6, the BS may determine whether data to be allocated resources is transmitted in seconds (S610). That is, the base station can determine whether to allocate resources for data to be allocated first, or to allocate resources for retransmission due to transmission failure, etc. The base station can allocate uplink resources according to a scheduling algorithm if the data to be allocated resources is a second transmission (S620). The base station can recover a previously allocated resource amount for data if the data to allocate the resource is not a second transmission (or retransmission). For example, the base station may correct the current data amount of the buffer by adding the amount of resources previously allocated to the data (e.g., the amount of resources allocated to each LCG before 8 subframes) to the current data amount of the buffer (S630) . The base station can allocate uplink resources according to the retransmission scheduling algorithm (S640). The retransmission scheduling can be performed in a non-adaptive retransmission, an adaptive retransmission, or a retransmission failure according to the current resource allocation situation, so that the second transmission can be performed. When the uplink resource is allocated to the base station, the base station can correct the current data amount of the buffer according to the allocated resource amount. For example, the base station can correct the current data amount of the buffer by subtracting the allocated dimension amount from the data amount of the buffer for each LCG.

7 is a flowchart illustrating a method by which a base station corrects a data amount of a buffer according to an embodiment of the present invention.

FIG. 7 shows a method in which a base station corrects a data amount of a buffer when a BSR is received from a terminal. Referring to FIG. 7, the BS may receive the BSR from the MS (S710). According to an exemplary embodiment, the BS may determine whether the BSR is a Long BSR when the BSR is received (S720). If the received BSR is Long BSR, the BS can set the data amount indicated by the BSR for all the LCGs to the current data amount of the buffer (S730). The base station subtracts the allocated resource amount (excluding the resource amount allocated at the time when the BSR is generated) from the point in time when the BSR is generated (for example, before 4 subframes) for all the LCGs of all the CCs in the set data amount, (S740).

If the received BSR is not a long BSR, the BS can set the data amount indicated by the BSR to the LCG indicated by the BSR as the current data amount of the buffer (S750). The BS subtracts the allocated resource amount (excluding the resource amount allocated at the time when the BSR is generated) from the time when the BSR is generated (for example, before 4 subframes) to the LCG indicated by the BSR in the set data amount, (S760). The base station may determine whether the received BSR is a Truncated BSR (S770). If the received BSR is a Truncated BSR, the terminal determines that BSR reception is scheduled for another LCG, and transmits the amount of data that can transmit the header of the Long BSR and the corresponding MAC CE to the LCG having the highest priority (for example, LCG 0) (S780).

8 is a flowchart illustrating a method for a base station to correct a data amount of a buffer according to an embodiment of the present invention.

FIG. 8 shows a method in which a base station corrects a data amount of a buffer when data is received from a terminal. Referring to FIG. 8, a base station can receive uplink data from a terminal (S810). The base station can calculate the amount of received data when the uplink data is received (S820). The base station may determine whether the BSR for the LCG on which the data is received has been received (S830). If the BSR for the LCG on which the data is received has been received, the base station can terminate the data amount correction of the buffer since the buffer size for the LCG has already been updated. If the BSR for the LCG on which the data is received has not been received, the base station may calculate the difference between the allocated resource amount and the received data amount for the received data (S840). The base station can correct the current data amount of the buffer using the difference between the allocated resource amount and the received data amount (S850). For example, the base station can increase the current data amount of the buffer by the difference between the allocated resource amount and the received data amount if the allocated resource amount is larger than the received data amount. In another example, the base station may reduce the current data amount of the buffer by the amount of allocated resources and the amount of received data if the allocated resource amount is less than the received data amount.

9 shows a wireless interface protocol structure according to an embodiment of the present invention.

Referring to FIG. 9, a physical layer (PHY) layer as a first layer provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to an upper layer MAC (Medium Access Control) layer through a transport channel, and data is transferred between the MAC layer and the physical layer through the transport channel.

Data moves between physical layers between different physical layers, that is, between a transmitting side and a receiving physical layer. The physical channel is modulated by an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and time and frequency can be utilized as radio resources.

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

The Packet Data Convergence Protocol (PDCP) layer of the second layer contains relatively large and unnecessary control information in order to efficiently transmit packets in a radio section having a small bandwidth during transmission of an IP (Internet Protocol) packet such as IPv4 or IPv6 And performs header compression to reduce the size of the IP packet header.

10 is a block diagram illustrating a configuration of a base station according to an embodiment of the present invention.

Referring to FIG. 10, the base station 200 may include a communication unit 210 and a control unit 220.

The communication unit 210 can communicate with the terminal. According to one embodiment, the communication unit 210 may transmit the uplink grant to the terminal. According to one embodiment, the communication unit 210 can receive uplink data from a terminal. According to one embodiment, the communication unit 210 may receive the BSR from the terminal.

The control unit 220 can control the overall operation of the base station 200. According to one embodiment, the control unit 220 may allocate uplink resources and control the uplink grant to be transmitted to the terminal. For example, when receiving a scheduling request from a mobile station, the control unit 220 may allocate uplink resources to which the mobile station can transmit the BSR. For example, when the BSR is received from the UE, the controller 220 may allocate uplink resources according to a scheduling algorithm.

The control unit 220 can set the data amount of the buffer indicated by the BSR to the current data amount of the buffer when the BSR is received from the terminal. For example, when a Long BSR is received, the amount of data indicated by the BSR for all LCGs can be set to the current amount of data in the buffer. In another example, when a Short BSR or Truncated BSR is received, the amount of data indicated by the BSR for the LCG indicated by the BSR may be set to the current amount of data in the buffer.

According to one embodiment, when the uplink resource is allocated, the controller 220 may correct the data amount of the buffer according to the allocated resource amount. For example, the control unit 220 may correct the current data amount of the buffer by subtracting the allocated resource amount from the current data amount of the buffer. According to one embodiment, the control unit 220 can set and correct the current data amount of the buffer for each logical channel group.

According to one embodiment, the control unit 220 may determine whether the data to be allocated resources is a second transmission or a retransmission, and may correct the current data amount of the buffer according to the determination result. For example, if the data to be allocated is a second transmission, the control unit 220 may correct the current data amount of the buffer by subtracting the allocated resource amount from the current data amount of the buffer. For example, if the data to be allocated is retransmitted, the control unit 220 may recover the amount of resources allocated in the past for the data to be allocated to the current amount of data in the buffer, The amount can be corrected.

According to one embodiment, when the BSR is received from the terminal, the controller 220 may correct the current data amount of the buffer by subtracting the resource amount allocated after the BSR is generated from the current data amount of the buffer. For example, when the BSR is received together with the uplink data from the UE in the SFN / SF = n + 4 according to the uplink grant transmitted from the UE to the UE in SFN / SF = n, That is, SFN / SF = n + 1, n + 2 and n + 3). According to one embodiment, when the long BSR is received, the control unit 220 can correct the current data amount of the buffer for all the LCGs. According to one embodiment, when the Short BSR or the Truncated BSR is received, the control unit 220 may correct the current data amount of the buffer for the LCG indicated by the BSR.

According to one embodiment, the control unit 220 can calculate the amount of received data when the uplink data is received from the terminal. According to one embodiment, the control unit 220 may correct the current data amount of the buffer using the difference between the amount of resources allocated and the amount of data received for the received data. For example, if the allocated resource amount is larger than the received data amount, the control unit 220 may increase the current data amount of the buffer by the difference between the allocated resource amount and the received data amount. In another example, if the allocated resource amount is less than the received data amount, the control unit 220 may reduce the current data amount of the buffer by a difference between the allocated resource amount and the received data amount. According to one embodiment, the controller 220 determines whether a BSR for the LCG on which the data is received has been received. If the BSR for the LCG on which the data is received has been received, since the buffer size for the LCG has already been updated, The amount correction is not performed.

According to one embodiment, when the Truncated BSR is received from the UE, the controller 220 determines that BSR reception is scheduled for another LCG from the UE, and transmits the Long BSR and the Long BSR to the LCG having the highest priority It is possible to add an amount of data that can transmit the header of the MAC CE.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

100: terminal 200: base station
210: communication unit 220:

Claims

A method for managing uplink buffer status of a base station,
Receiving a buffer status report (BSR) from a terminal;
Setting a data amount of a buffer indicated by the buffer status report to a first current data amount of the buffer;
Allocating an uplink resource to the terminal; And
Wherein the BS calculates a current data amount of the buffer by subtracting a resource amount of the UL resource allocated to the UE from the first current data amount of the buffer based on the buffer status report received from the UE Correcting;
&Lt; / RTI >

The method according to claim 1,
And correcting the current data amount of the buffer by subtracting the amount of resources allocated after the generation of the buffer status report from the current data amount of the buffer.

The method according to claim 1,
Receiving uplink data from a terminal;
Calculating a received data amount;
Calculating a difference between the amount of resources allocated to the received data and the amount of received data; And
And correcting the current data amount of the buffer using the difference between the allocated resource amount and the received data amount.

The method of claim 3,
Wherein the step of correcting the current data amount of the buffer using the difference between the allocated resource amount and the received data amount comprises:
Increasing the current data amount of the buffer by the difference if the allocated resource amount is greater than the received data amount; And
And decreasing the current data amount of the buffer by the difference if the allocated resource amount is less than the received data amount.

The method according to claim 1,
The buffer status report includes:
And an index indicating the amount of data in the buffer for at least one logical channel group,
The step of correcting the current data amount of the buffer comprises:
A method for correcting a current data amount of a buffer for each logical channel group.

The method according to claim 1,
Determining whether data to be allocated resources is a second transmission or a retransmission; And
And correcting the current data amount of the buffer by adding a resource amount previously allocated to the data to the current data amount of the buffer if the data is a retransmission.

A communication unit for communicating with the terminal; And
The method comprising: setting a data amount of a buffer indicated by the buffer status report to a first current data amount of the buffer when receiving a buffer status report from the terminal, allocating uplink resources to the terminal, A controller for correcting the current data amount of the buffer by subtracting the resource amount of the uplink resource allocated to the terminal by the base station from the first current data amount of the buffer, which is determined based on the received buffer status report; / RTI >

8. The method of claim 7,
Wherein,
And corrects the current data amount of the buffer by subtracting a resource amount allocated after a point in time when the buffer status report is generated from the current data amount of the buffer.

8. The method of claim 7,
Wherein,
Wherein the base station calculates the amount of received data when the uplink data is received from the terminal and corrects the current data amount of the buffer using the difference between the amount of resources allocated to the received data and the amount of received data.

10. The method of claim 9,
Wherein,
Increases the current data amount of the buffer by the difference if the allocated resource amount is larger than the received data amount and decreases the current data amount of the buffer by the difference if the allocated resource amount is smaller than the received data amount Base station.

8. The method of claim 7,
The buffer status report includes:
And an index indicating the amount of data in the buffer for at least one logical channel group,
Wherein,
And corrects the current data amount of the buffer for each logical channel group.

8. The method of claim 7,
Wherein,
Wherein the current data amount of the buffer is corrected by adding the amount of resources previously allocated to the data to the current data amount of the buffer if the data to be allocated is retransmission or retransmission.