KR20090101786A - Apparatus and method for transmitting mac pdu in mobile communication system - Google Patents

Abstract

PURPOSE: An apparatus and a method for producing an MAC(Medium Access Control) PDU(Protocol Data Unit) in a mobile communication system are provided to overcome troubles generated when producing and optimizing an MAC header by including the specific MAC control information according to the canceled size in an MAC PDU after canceling a final F field and an LEN filed. CONSTITUTION: A method for producing and transmitting an MAC(Medium Access Control) PDU(Protocol Data Unit) in a mobile communication system is composed of the steps of inspecting whether the size of TB allocated from the base station meets the predetermined specific condition or not when producing the MAC PDU(420), producing the MAC PDU after excepting a BSR(Buffer State Report) from the MAC PDU if the size of TB allocated from the base station meets the predetermined specific condition(435), and transmitting the produced MAC PDU through a physical layer.

Description

Apparatus and method for generating a media access control protocol data unit in a mobile communication system {APPARATUS AND METHOD FOR TRANSMITTING MAC PDU IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to an apparatus and a method for generating a medium access control (MAC) protocol data unit (PDU).

Today's mobile communication systems have evolved from providing voice-oriented services to high-speed, high-quality wireless data packet communication systems for providing data and multimedia services. Among these mobile communication systems, it is based on the European mobile communication system GSM (Global System for Mobile Communications) and GPRS (General Packet Radio Services), and Wideband Code Division Multiple Access (hereinafter referred to as CDMA) UMTS (Universal Mobile Telecommunication Service) system, a third-generation mobile communication system that uses PSP, delivers packet-based text, digitized voice or video and multimedia Provide a consistent service that can be delivered. The UMTS system uses a packet-switched connection concept using a packet protocol such as the Internet Protocol (hereinafter referred to as 'IP'), and can always be connected to any other end in the network.

The 3rd Generation Partnership Project (3GPP), which is in charge of standardizing UMTS systems, is discussing Long Term Evolution (LTE) as the next generation mobile communication system of UMTS systems. LTE is a technology for implementing high-speed packet-based communication of about 100 Mbps, and various methods have been discussed for this purpose. For example, a method of simplifying a network structure to reduce the number of nodes located on a communication path or a method of bringing wireless protocols as close as possible to a wireless channel is under discussion.

1 is a diagram illustrating the role of the MAC layer in a general LTE mobile communication system.

Referring to FIG. 1, in the transmitting side, radio link control (hereinafter, referred to as 'RLC') layer entities 102 and 104 include one RLC PDU for an RLC SDU (Service Data Unit) received from an upper layer. It is configured to transmit to the MAC layer 106. The RLC PDU is transmitted by the MAC layer 106 via the physical layer 108 to the receiving side. The MAC PDU arrived at the MAC layer 112 via the physical layer 110 at the receiving side is converted into a MAC SDU and delivered to the corresponding RLC layer entities 114 and 116. The RLC layer entities 114 and 116 extract an RLC SDU from the RLC PDU and deliver it to the higher layer.

Here, the RLC PDU is interpreted as a MAC SDU from the viewpoint of the MAC layer 106. The MAC layer 106 configures and combines MAC headers to form one MAC PDU. The MAC PDU may include MAC SDUs for control that can be exchanged with each other in the MAC layer in addition to the MAC SDUs downloaded from the RLC layer entities 102 and 104. The MAC SDU for control may be transmitted together with the MAC SDUs for data transmission in the MAC PDU, or may be included in the MAC PDU alone. Accordingly, the header of the MAC PDU (hereinafter referred to as 'MAC header') is configured to distinguish between MAC SDU for data transmission and MAC SDU for control.

2 is a diagram illustrating a configuration of a MAC PDU used in an LTE system.

As shown in FIG. 2, the MAC PDU 205 uses MAC control information such as a buffer status report (hereinafter, referred to as a “BSR”) 210 to report a buffer status of a terminal. And a plurality of RLC PDUs 215 and 230, MAC headers corresponding to respective MAC control information and RLC PDUs, and each RLC PDU 215 or 230 is concatenated with RLC SDUs (220, 225). It is segmented (235) and configured with the addition of an RLC header.

Referring to FIG. 2, MAC control information such as the BSR 210 is prioritized when generating a MAC PDU in consideration of the size of a transport block (hereinafter referred to as “TB”), which is a size of an allocated resource received from a terminal. The RLC PDUs 215 and 230 are stored in consideration of the priority of each logical channel. If the size of the TB is not considered to accommodate the BSR 210, it is large enough to accommodate all of the RLC data 220, 225, 235, 240 and the corresponding RLC header generated in the terminal, but additionally If it is not enough to accommodate the BSR 210, the storage of the BSR 210 is canceled and the pending RLC SDU 240 is stored to transmit the last remaining pending data 240 more quickly.

However, the advantage of the method of preferentially transmitting the last data over the BSR is that the BSR is retransmitted after the last data transmission, except in the case of data requiring fast and non-separable transmission such as VoIP packet transmission. In terms of resource efficiency, efficiency is reduced. In addition, there is a problem of increasing complexity in terms of implementation.

Also, referring to FIG. 2, each MAC subheader 205, 210 receives multiplexing information on a corresponding MAC SDU or MAC control information 215, 220 stored in a MAC PDU. As many MAC subheaders 205 and 210 as the number of MAC SDU or MAC control information 215 and 220 are accommodated in the MAC PDU, and MAC subheaders 205 and 210 and MAC SDU or MAC control information 215 and 220 are included. ) Is determined according to the order in which the payloads 215 and 220 are stored. For example, the first MAC subheader 205 corresponds to the first MAC SDU or MAC control information 215, and the second MAC subheader 210 corresponds to the second MAC SDU or MAC control information 220.

Each MAC subheader 205, 210 contains an R (225, 230), an E (235), an LCID (240), an F (245), and an LEN (250) field. In order to reduce the processing load of the transceiver, the MAC subheaders 205 and 210 are byte-aligned, and two bits of R fields 225 and 230 are used for this purpose. The E field 235 indicates whether the corresponding MAC subheader is the last MAC subheader, and the LCID 240 indicates the identifier of the logical channel of the corresponding MAC SDU or the type of the corresponding MAC control information. The LEN field 250 indicates the size of MAC SDU or MAC control information. The LEN field 250 is 7 bits or 15 bits, and the F field 245 preceding the LEN field 250 indicates its length. For example, if the F field 245 is 0, the associated LEN field 250 is 7 bits, and if the F field 245 is 1, the associated LEN field 250 is 15 bits. The LEN field 250 indicates up to 127 bytes when 7 bits and up to 32768 bytes when 15 bits.

In this case, in FIG. 2, the F field and the LEN field corresponding to the last MAC SDU of the MAC PDU or the MAC subheader 210 of the MAC control information 220 are omitted in a typical mobile communication system. The reason is that since the size of a transport block (TB) representing the length of the entire MAC PDU is known to the receiving side in advance, the F field is obtained by subtracting the length of the MAC SDU stored in the LEN field of each MAC SDU in the total length. This is because the lengths of the remaining MAC SDUs in which the and LEN fields are omitted can be estimated. If the last F field and the LEN field are omitted, the F field and the LEN field are always deleted at the same time in consideration of byte alignment. In order to omit the F field and the LEN field of one of the MAC SDUs multiplexed in the MAC PDU as described above, the receiver is identified to identify the MAC SDU from which the F and LEN fields of the multiplexed MAC SDUs are omitted. Alternatively, the transceiver must be promised in advance to omit the F field and the LEN field for the MAC SDU at a particular location. In general, it is common to omit the F field and the LEN field for the last MAC SDU among the MAC SDUs multiplexed in the MAC PDU.

However, even when the last F field and the LEN field are omitted, padding is added to fit the MAC PDU to the size of the transport block in constructing the MAC PDU. If the length of the padding required to generate the MAC PDU is longer than the length of the omitted last F field and LEN field, the added padding will again include the omitted F field and LEN field, but added padding. Can be maintained without being deleted. However, the length of the padding required to generate the MAC PDU is shorter than or equal to the sum of the lengths of the omitted last F field and the LEN field (when the length of the padding is greater than zero, that is, the padding is present). The following applies to both the length of the padding and the condition for the sum of the lengths of the last F field and the LEN field), and the MAC subheader for the padding added to the MAC header to indicate the padding (hereinafter referred to as padding header). Since the omitted F field and the LEN field are no longer MAC subheaders for the last MAC SDU, the omitted F field and the LEN field should be included again, which causes the contradiction that the padding should be deleted again. Occurs.

The present invention provides an apparatus and method for simplifying the conditions for determining BSR containment.

The present invention also provides an apparatus and method that can reduce the complexity for the transmission of the BSR.

The present invention also provides an apparatus and method for increasing the transmission efficiency of a wireless channel.

The present invention also provides an apparatus and method for generating a MAC PDU having an optimized MAC header in a mobile communication system.

Also, when the last length field is omitted for optimizing the MAC header, if the padding size required for generating the MAC PDU is equal to or smaller than the sum of the size of the F field and the LEN field, the last F field and the LEN field may be selected. An apparatus and method for constructing a MAC PDU by omitting and generating MAC control information corresponding to sizes of the omitted last F field and LEN field are provided.

In addition, the method according to the present invention is a method for generating and transmitting a medium access control (MAC) protocol data unit (PDU) in a mobile communication system, the specific condition in which the size of TB allocated from the base station at the time of generation of the MAC PDU is predetermined Checking whether it is satisfied, excluding a buffer status report (BSR) from the MAC PDU when the specific condition is satisfied, generating a MAC PDU, and transmitting the generated MAC PDU through a physical layer It includes.

In addition, the apparatus according to the present invention is a device for generating and transmitting a medium access control (MAC) protocol data unit (PDU) in a mobile communication system, the specific condition that the size of the TB allocated from the base station in the generation of the MAC PDU is predetermined And a MAC controller for controlling to generate a MAC PDU by excluding a buffer status report (BSR) from the MAC PDU when the specific condition is satisfied, and a header of the MAC PDU under the control of the MAC controller. And a header generation unit for generating a multiplexer, at least one radio link control unit for generating and providing the MAC SDU, and a multiplexer for multiplexing the output of the radio link control unit and the output of the header generation unit under control of the MAC control unit.

In addition, a method for generating a medium access control (MAC) protocol data unit (PDU) in a mobile communication system according to the present invention includes the steps of generating a MAC subheader for each MAC SDU, wherein each MAC SDU comprises: If the size of the total padding required for the generation of the MAC PDU is greater than the size of the last F field and the LEN field, including padding added to omit the F field and the LEN field for the last MAC SDU in generating the MAC PDU. The last F field and the LEN field are omitted without being included in the MAC header, and if padding is added to omit the F field and the LEN field for the last MAC SDU in generating a MAC PDU including each MAC SDU. The last F field if the total padding size required to generate the MAC PDU is less than or equal to the sum of the sizes of the last F field and the LEN field. And generating a MAC PDU by omitting the LEN field and including specific MAC control information corresponding to the omitted size in the MAC PDU, attaching the MAC header to a payload including each MAC SDU. do.

When the effect obtained by the typical thing of the invention disclosed in this invention is demonstrated briefly, it is as follows.

As described above, when the length of the padding required to generate the MAC PDU is shorter than or equal to the sum of the lengths of the last F field and the LEN field, the present invention omits the last F field and the LEN field and corresponds to the omitted size. Including specific MAC control information in the MAC PDU has an effect of overcoming problems that may occur when generating and optimizing the MAC header.

1 is a view showing the role of the MAC layer in a general LTE mobile communication system,

2 illustrates configurations of a MAC PDU in a typical mobile communication system.

3 is a block diagram showing a configuration of an apparatus for generating and transmitting a MAC PDU at a transmitting end of a mobile communication system according to an embodiment of the present invention;

4 is a flowchart illustrating an operation of generating a MAC PDU in a mobile communication system according to a first embodiment of the present invention;

5 is a flowchart illustrating an operation of generating a MAC PDU in a mobile communication system according to a second embodiment of the present invention;

6 is a flowchart illustrating an operation of generating a MAC PDU in a mobile communication system according to a third embodiment of the present invention;

7 is a flowchart illustrating an operation of generating a MAC PDU in a mobile communication system according to a fourth embodiment of the present invention;

8 is a flowchart illustrating an operation of generating a MAC PDU in a mobile communication system according to a fifth embodiment of the present invention;

9 is a flowchart illustrating an operation of generating a MAC PDU including a MAC header at a transmitting end of a mobile communication system according to a sixth embodiment of the present invention;

10 is a flowchart illustrating an operation of generating a MAC PDU including a MAC header at a transmitting end of a mobile communication system according to a seventh embodiment of the present invention;

11 is a flowchart illustrating an operation of generating a MAC PDU including a MAC header at a transmitting end of a mobile communication system according to an eighth embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

In the following description, the 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) system based on Universal Mobile Telecommunication Services (UMTS) will be used. However, the configuration of the MAC header, which is a basic object of the present invention, can be applied to other mobile communication systems having similar technical backgrounds and channel types with a slight modification without departing from the scope of the present invention. In the judgment of those skilled in the art will be possible.

An important aspect of the present invention is to generate a protocol data unit (PDU) of a media access control (MAC) layer in a mobile communication system, and in particular, to provide a scheme for simplifying the process of generating a MAC PDU.

In addition, the main subject of the present invention is to generate a protocol data unit (PDU) of the media access control (MAC) layer in a mobile communication system, and in particular, to provide a method for optimizing the size of the MAC header.

The overall operation of the method according to the invention is described first. The UE performs the following process to determine whether to receive the BSR when generating the MAC PDU.

First step: MAC PDU is generated through resource allocation for each logical channel in consideration of BSR size.

Step 2: If the BSR is not stored, check whether all remaining data can be transmitted.

Step 3-1: If all remaining data can be transmitted in the second step, the BSR reception is canceled, the remaining data is stored, a new MAC PDU is generated and transmitted to the lower layer.

Step 3-2: If all data remaining in the second step cannot be transmitted, the MAC PDU generated in the first step is transmitted to the lower layer.

The first step is a general process, but since the second step has many factors to consider, the complexity of the actual implementation is large. For example, whether the remaining data is configured as a separate RLC PDU or stored by reconstructing an existing RLC PDU, considering the size of the RLC header according to the RLC mode, whether the RLC re-segmentation, the size of the RLC framing header, etc. It is determined whether all the remaining data can be accommodated.

The present invention will now be described in detail. In describing the present invention in detail, a 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) system based on Universal Mobile Telecommunication Services (UMTS) will be used. However, the configuration of the MAC header, which is a basic object of the present invention, is applicable to other mobile communication systems having a similar technical background and channel form with a slight modification without departing from the scope of the present invention. In the judgment of those skilled in the art will be possible.

According to the first embodiment of the present invention, if the specified specific condition is satisfied, the MAC PDU is generated without storing the BSR. That is, the estimated value Δ for the L2 header size is promised in advance between the terminal and the base station. Here, the estimated value may separately define an estimated value of the L2 header size for each logical channel defined in the terminal, and may reflect the sum of the estimated values of the L2 header sizes for each logical channel defined above. Alternatively, the estimated value may define an estimated value of a common L2 header size for each logical channel defined in the terminal and reflect the estimated value as a product of the number of logical channels defined in the terminal. Alternatively, the estimate may be reflected as an estimate of the total L2 header size to be included in the MAC PDU.

An approximation value of the MAC PDU size to be transmitted is calculated by using the estimated value and the size of data in the terminal buffer and the BSR information to be stored. An approximation value of the TB size received from the base station and the MAC PDU size before the first step is calculated. By comparison, it is determined whether or not to receive the BSR information. The process proceeds to the above-described step 3-1 or 3-2.

In the second embodiment of the present invention, the priority of a predetermined logical channel through which data that is required to be transmitted as quickly as possible, such as a VoIP packet, is transmitted as a priority higher than the BSR to separate packets due to the BSR. Prevent it in advance.

According to the third embodiment of the present invention, when the transmission of the BSR is triggered, only the predetermined logical channel through which data is required to be transmitted as fast as possible without separation, such as a VoIP packet, is transmitted through the above-described second step. Determine whether to cancel.

In the fourth embodiment of the present invention, it is determined whether the BSR storage is canceled through the above-described second step only when the received TB size is equal to or smaller than a predetermined reference value.

In the fifth embodiment of the present invention, it is determined whether the BSR storage is canceled through the above-described second step only when the set number of logical channels is equal to or less than a predetermined reference value.

Next, the block configuration of the apparatus according to the present invention and the control flow according to the embodiments will be described with reference to the accompanying drawings.

3 is a block diagram of an apparatus for generating and transmitting a MAC PDU in a transmitter of a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, an apparatus for generating a MAC PDU includes a multiplexer (MUX) 300, RLC entities 302, 304, and 306, a MAC controller 308, and a header generator 310. do. The RLC units 302, 304, and 306 transmit MAC SDUs to be transmitted to the multiplexer 300, and provide LCID information and length information of the MAC SDUs to be transmitted to the header generator 310. The MAC controller 308 transmits a MAC SDU to the multiplexer 300 when there is a MAC SDU for controlling the MAC protocol, and the LCID information of the MAC SDU for the control and the length of the MAC control information are variable. In this case, length information is provided to the header generator 310.

The header generator 310 generates a MAC header for each MAC SDU or MAC control information received from the RLC units 302, 304, and 306 and the MAC controller 308, and outputs the MAC header to the multiplexer 300. And control the order of MAC SDUs to be included in the MAC PDU through the multiplexer 300.

Next, an example of configuring a MAC PDU according to each embodiment of the present invention will be described in a transmission apparatus having the configuration of FIG. 3. In addition, in the present invention described below, an operation for minimizing complexity when generating MAC PDU when BSR transmission is triggered will be described together.

4 is a flowchart illustrating a transmission operation according to the first embodiment of the present invention.

Referring to FIG. 4, in step 405, the transmitter of the terminal recognizes an estimated value Δ for the promised L2 header size. Here, the estimated value may separately define an estimated value of the L2 header size for each logical channel defined in the terminal, and may reflect the sum of the estimated values of the L2 header sizes for each defined logical channel. Alternatively, the estimated value may define an estimated value of a common L2 header size for each logical channel defined in the terminal and reflect the estimated value as a product of the number of logical channels defined in the terminal. Alternatively, the estimate may be reflected as an estimate of the total L2 header size to be included in the MAC PDU. The estimated value may be a fixed value or a value received by the terminal through broadcast information, or a value assigned only to the terminal. The estimated value may be determined separately for each logical channel set in the terminal by the base station or for the terminal. It can be determined by one value. The estimated value may be promised between the base station and the terminal in a method other than the above-described method.

When the estimation value is determined as described above, the UE triggers the transmission of the BSR in step 410, and checks the size of the TB allocated from the base station in step 415. Thereafter, the terminal determines whether to store the BSR in the MAC PDU using the estimated value promised in step 420, the amount of data waiting to be transmitted to the current buffer of the terminal, and the size of the triggered BSR. As a result of step 420, if the size of the TB received from the base station satisfies the following condition, the process proceeds to step 425, otherwise proceeds to step 430.

<Conditional expression>

Total buffer size + △ <TB size ≤ Total buffer size + △ + BSR size

If the terminal proceeds to step 425, it cancels the reception of the triggered BSR and proceeds to step 430. On the other hand, if the size of the TB received from the base station does not satisfy the conditional expression as a result of step 420, the process proceeds to step 430. In step 430, if it is determined that the triggered BSR is not received according to whether the conditional expression is satisfied, that is, if the process proceeds to step 425, the resource corresponding to the size of the TB is received without considering the triggered BSR. Channel: LCH) is allocated according to priority. In addition, when it is determined to receive the triggered BSR according to whether the conditional expression is satisfied. In consideration of the triggered BSR, a resource corresponding to the received TB size is allocated for each logical channel. In step 435, a MAC PDU is generated by combining the MAC SDUs generated as a result of step 430, and the MAC PDU is transmitted to a lower layer. In step 440, when the triggered BSR is not stored in the MAC PDU. When data remains in the buffer of the terminal due to the estimation error for the estimated value, the BSR is triggered again.

5 is a control flowchart of a transmission operation according to a second embodiment of the present invention.

Referring to FIG. 5, when an RB (Radio Bearer or Logical Channel) is set between the base station and the UE in step 505, the process proceeds to step 510 where the RB is configured to receive data requiring fast transmission without separation as possible as VoIP packets. Check whether it is a predetermined logical channel for transmission. In step 510 of FIG. 5, the real-time packet is considered to be an embodiment. This is described as an example of satisfying the above condition. If the RB is a predetermined logical channel for transmitting data requiring fast transmission without being separated as much as possible, such as VoIP packets, the data of the predetermined logical channel is greater than the BSR when the MAC PDU is generated. In order to prioritize, the process proceeds to step 515 to set the priority of the predetermined logical channel used when the terminal allocates resources for each logical channel higher than the priority of the BSR.

Thereafter, if the BSR transmission is triggered in step 520, and TB size is allocated from the base station in step 525, in step 530, the UE resources for each logical channel based on the received TB size and priority of each logical channel set in the UE. Allocate In step 505, 510 and 515, a higher priority is assigned to a predetermined logical channel for transmitting data that requires fast and inseparable transmission such as a VoIP packet. Segmentation of data transmitted on a given logical channel does not occur. Therefore, in step 530, it is not considered whether to cancel the BSR storage. In step 535, the MAC PDU is generated and the generated MAC PDU is transmitted to a lower layer.

6 is a flowchart illustrating a transmission control according to a third embodiment of the present invention.

Referring to FIG. 6, in step 605, transmission of a BSR is triggered. In step 610, when a TB size is allocated from a base station, in step 615, resources are allocated to each logical channel set in a terminal in consideration of the triggered BSR. Proceed to step 620. In step 620, if there is a predetermined logical channel for transmitting data requiring fast and inseparable transmission, such as a VoIP packet, the terminal does not store the triggered BSR in the MAC PDU to the predetermined logical channel. It is checked whether all remaining data to be transmitted can be stored in the MAC PDU. In other words, the terminal determines whether the triggered BSR is received only for the predetermined logical channel for transmitting data requiring fast transmission without being separated, such as a VoIP packet requiring real time, and the condition of step 620 is determined. If it is established, the process proceeds to step 625 to cancel the reception of the triggered BSR and proceeds to step 630 to generate a MAC PDU and transmits the generated MAC PDU to the lower layer. If the condition of step 620 is not satisfied, the process proceeds to step 630 to generate a MAC PDU and transmits the generated MAC PDU to a lower layer.

7 is a flowchart illustrating a transmission control according to a fourth embodiment of the present invention.

Referring to FIG. 7, in step 705, the transmitter of the terminal recognizes the promised reference value X. The X may be a fixed value or a value received by the terminal through broadcast information, or a value assigned only to the terminal. X may also be promised between the base station and the terminal in a manner other than the above-described method. If the transmission of the BSR is triggered in step 710, and checks the TB size allocated from the base station in step 715. Thereafter, the terminal proceeds to step 717 to check whether the size of the TB is less than or equal to the reference value X. If the TB size is less than or equal to the reference value X, the process proceeds to step 720; otherwise, the process proceeds to step 730. In step 720, if the terminal does not store the BSR, the terminal checks whether all data remaining in the buffer can be transmitted. If it is possible to transmit all the data remaining in the buffer when the BSR is not stored in step 720, the process proceeds to step 725.

The terminal cancels the reception of the triggered BSR in step 725 and proceeds to step 730. On the other hand, if the conditions of steps 717 and 720 are not satisfied, the process proceeds to step 730. In this case, when the TB size received from the base station is larger than the promised X byte, the process may proceed to step 730 without considering whether to cancel the triggered BSR reception, thereby improving the complexity of the MAC PDU generation process. In step 730, if it is determined that the triggered BSR is not received according to the results of steps 717 and 720, each logical channel is allocated according to the priority of the resource equal to the received TB size without considering the triggered BSR. : Allocates by LCH).

In addition, when it is determined to receive the triggered BSR according to the result of operation 717 or 720, the resource corresponding to the received TB size is allocated to each logical channel in consideration of the triggered BSR. In step 735, a MAC PDU is generated by combining the MAC SDUs generated as a result of step 730, and the MAC PDU is transmitted to a lower layer.

8 is a transmission control flowchart according to a fifth embodiment of the present invention.

Referring to FIG. 8, in step 805, the transmitter of the terminal recognizes the promised reference value Y. The Y may be a fixed value or a value received by the terminal through broadcast information, or a value assigned only to the terminal. And Y may be promised between the base station and the terminal in a manner other than the above-described method. Thereafter, the UE triggers transmission of the BSR in step 810. Thereafter, the terminal checks the UL resource and the allocated TB size from the base station in step 815, and proceeds to step 817. In step 817, the terminal checks whether the number of logical channels set in the terminal is Y or less. If the number of logical channels is less than or equal to Y, the process proceeds to step 820. Otherwise, the process proceeds to step 830. If the terminal proceeds to step 820, if the BSR is not stored, it checks whether all data remaining in the buffer can be transmitted. If the test result of step 820 does not store the BSR, the process proceeds to step 825 when all data remaining in the buffer can be transmitted.

If the terminal proceeds to step 825, the terminal cancels the reception of the triggered BSR and proceeds to step 830. However, if any condition of step 817 or step 820 is not satisfied, and proceeds to step 830, logical channels are configured according to priority. As described above, if any of the conditions of steps 817 and 820 is not satisfied, and proceeds to step 830, logical channels may be configured according to priorities without considering whether to cancel the triggered BSR storage. In this case, it is not necessary to consider whether to cancel the BSR storage, thereby improving the complexity of the MAC PDU generation process.

On the other hand, in step 830, if it is determined not to receive the triggered BSR according to the results of steps 817 and 820, that is, proceeding to step 825, the resource equal to the received TB size without considering the triggered BSR. Is assigned to each logical channel. Thereafter, in step 835, MAC SDUs are generated by combining the MAC SDUs generated as a result of step 830, and the MAC PDUs are transmitted to a lower layer.

Meanwhile, as described above, in the format of a general MAC PDU, the size of the MAC subheader is 1 byte, 2 bytes, or 3 bytes. Since the LEN field and the F field are omitted in the last MAC subheader, the size of the last MAC subheader is usually 1 byte. If one or two bytes of padding occur when the F field and the LEN field of the last MAC subheader are removed, the above contradiction occurs.

Therefore, in the preferred embodiment of the present invention, when the size of the padding generated when the last F field and the LEN field is removed is 1 byte, a dummy padding having a size corresponding to the expected padding size is inserted and used. If the size of padding generated when the last F field and the LEN field are removed is 2 bytes, MAC control information having a fixed length of 2 bytes, including a MAC subheader, is stored in the MAC PDU and the 2 bytes The F field and the LEN field of the last MAC SDU may be removed to overcome a problem that occurs when the size of the padding generated when the last F field and the LEN field mentioned above is 1 byte or 2 bytes.

In storing MAC control information when the size of the padding generated when the last F field and the LEN field is removed is 2 bytes, buffer status information is stored in the MAC PDU before storing the MAC control information. If no BSR) is included, a short BSR having a total size of 2 bytes including a 1-byte MAC subheader and a 1-byte BSR corresponding to the BSR is stored, and the MAC PDU before storing the MAC control information. If a BSR is included in the MAC control information, a PHR having a total size of 2 bytes consisting of 1 byte of MAC subheader and 1 byte of Power Headroom Report (PHR) information is stored as the MAC control information. If the MAC PDU includes both the BSR and the PHR before storing, the MAC PDU is generated by storing any MAC control information among the short BSR and the PHR.

Alternatively, when storing the MAC control information when the size of the padding generated when the last F field and the LEN field are removed is 2 bytes, the MAC PDU is stored prior to storing the MAC control information by considering PHR first. If a PHR is not included in the PHR, a full 2 byte PHR consisting of a 1 byte MAC subheader and 1 byte of PHR information corresponding to the PHR is stored, and the PHR is stored in the MAC PDU before storing the MAC control information. If included, the entire 2 byte sized short BSR consisting of a 1-byte MAC subheader and 1-byte BSR information is stored as the MAC control information, and the BSR and PHR in the MAC PDU before storing the MAC control information. If it contains both of the short BSR and PHR arbitrary MAC control information is received to generate a MAC PDU.

Or when storing the MAC control information when the size of the padding generated when the last F field and the LEN field is removed is 2 bytes, the BSR is not included in the MAC PDU before the MAC control information is received. If a short BSR having a total size of 2 bytes consisting of a 1 byte MAC subheader and a 1 byte BSR corresponding to the BSR is stored, and if a short BSR is included in the MAC PDU before storing the MAC control information, it is already stored. And a short BSR for another Logical Channel Group (LCG) different from the short BSR, and if the MAC PDU includes a long BSR before storing the MAC control information, the MAC subheader of 1 byte and A PHR having a total size of 2 bytes consisting of 1 byte of PHR information is stored as the MAC control information, and BSR and PHR are stored in the MAC PDU before storing the MAC control information. If it contains two and generates a MAC PDU by receiving any MAC control information of the short BSR and PHR.

Here, the BSR is information for reporting the buffer status of the UE. The BSR is divided into a short BSR having a total size of 2 bytes including a corresponding MAC subheader or a long BSR having a size of 4 bytes, and the short BSR reports a buffer status of one LCG and is long. The BSR reports the buffer status for the entire LCG. The PHR is information for reporting an uplink transmission power state of the terminal and has a size of 2 bytes in total. In the above embodiment, when appropriate MAC control information having a size of 2 bytes is defined in addition to the short BSR or PHR, it may be applied like the short BSR or PHR.

Hereinafter, an operation of generating a MAC PDU in which the size of the header of the MAC PDU is optimized using the length field of the MAC subheader according to the present invention configured as described above will be described with reference to the accompanying drawings.

9 is a flowchart illustrating a transmission operation according to a sixth embodiment of the present invention.

Referring to FIG. 9, in step 905, the transmitter detects occurrence of a MAC PDU generation event. For example, when receiving the uplink transmission resource and the size of the MAC PDU from the base station scheduler, the UE recognizes that the MAC PDU corresponding to the size of the indicated MAC PDU should be generated, and the transmitter determines that the size of the MAC PDU is higher than the size of the indicated MAC PDU. By referring to the amount of data stored in the hierarchical buffer, logical channels for data transmission are determined, and the size of MAC SDU to be generated for each logical channel is determined. The remaining MAC subheaders except the last MAC subheader for each MAC SDU are generated according to a conventional procedure according to the size of the MAC SDU to be generated for each logical channel.

In step 910, when the transmitter removes the F field and the LEN field of the last MAC subheader, it checks whether 1 byte of padding occurs when the size of the LEN field is 7 bits. If the size is 15 bits, it checks whether one or two bytes of padding occur (i.e., if padding is less than or equal to the sum of the size of the F field and the LEN field except the case of 0 byte padding).

As a result of checking whether the padding occurs, the process proceeds to step 930 if the padding occurs, and if not, the process proceeds to step 915.

In step 915, the transmitter determines whether padding does not occur even if the F / LEN field of the last MAC subheader is removed. In step 915, when the transmitter does not have padding, the MAC subheader is the last MAC subheader. Therefore, in step 925, the transmitter sets the E field of the last MAC subheader to '0' and the F field of the last MAC subheader. Omit the and LEN fields. On the other hand, by removing the F / LEN field of the last MAC sub-header in step 915, if more than two bytes of padding occurs when the size of the LEN field is 7 bits, or more than 3 bytes of padding when the size of the LEN field is 15 bits If it occurs (i.e., checks whether padding is greater than the sum of the size of the F field and the LEN field), then the MAC subheader is no longer the last MAC subheader due to the addition of padding, so in step 420 the transmitter sends the E field. Set to '1' and generate a MAC subheader according to a conventional procedure, generate a MAC subheader for the padding to be added and as much padding as necessary and store it as the actual last MAC SDU.

 In step 970, the transmitter generates a MAC header by combining the generated MAC subheaders. In step 975, the transmitter generates a MAC PDU.

Meanwhile, in step 910, when the transmitter generates the last MAC subheader, if the F field and the LEN field of the last MAC subheader are removed, if the size of the LEN field is 7 bits, 1 byte of padding is generated or the LEN field is generated. If the size of 15 bit is 1 byte or 2 bytes of padding occurs, the process proceeds to step 930.

In step 930, the transmitter determines whether 1 byte padding has occurred in the conditions of step 910, and when 1 byte padding occurs, the transmitter proceeds to step 935 to store the 1-byte dummy padding.

In step 930, when the 1-byte padding does not occur, that is, when 2-byte padding occurs, in step 940, the transmitter sets the E field of the last MAC subheader to '0' and the F of the last MAC SDU. Omit the / LEN field.

In step 945, the transmitter determines whether a BSR exists among MAC control information already stored in the MAC PDU, and when the BSR does not exist, in step 950, the transmitter stores the MAC subheader and the short BSR MAC control information for the short BSR. On the other hand, in step 945, if there is a BSR already stored in the MAC PDU, the transmitter proceeds to step 955 and checks whether there is a PHR in the MAC control information already stored in the MAC PDU.

If the PHR does not exist in step 955, the transmitter proceeds to step 960 to store the MAC subheader and PHR MAC control information for the PHR. In contrast, in step 955, if the BSR and the PHR have already been stored in the MAC PDU, the transmitter proceeds to step 965 and selects any of the short BSR or the PHR to store the corresponding MAC subheader and the MAC control information.

Then, as described above, in step 970, the transmitter generates the MAC header by combining the generated MAC subheaders. In step 975, the transmitter completes generation of the MAC PDU.

10 is a flowchart illustrating a transmission operation according to a seventh embodiment of the present invention.

Referring to FIG. 10, in step 1005, the transmitter detects occurrence of a MAC PDU generation event. For example, when receiving the uplink transmission resource and the size of the MAC PDU from the base station scheduler, the UE recognizes that the MAC PDU corresponding to the size of the indicated MAC PDU should be generated, and the transmitter determines that the size of the MAC PDU is higher than the size of the indicated MAC PDU. By referring to the amount of data stored in the hierarchical buffer, logical channels for data transmission are determined, and the size of MAC SDU to be generated for each logical channel is determined. The remaining MAC subheaders except the last MAC subheader for each MAC SDU are generated according to a conventional procedure according to the size of the MAC SDU to be generated for each logical channel.

In step 1010, when the transmitter removes the F field and the LEN field of the last MAC subheader, it checks whether 1 byte of padding occurs when the size of the LEN field is 7 bits. If the size is 15 bits, it checks whether one or two bytes of padding occur (that is, if padding is less than or equal to the sum of the size of the F field and the LEN field except the case of 0 byte padding).

As a result of checking whether the padding is generated, if the padding occurs, the process proceeds to step 1030, otherwise proceeds to step 1015.

In step 1015, the transmitter checks whether padding does not occur even if the F / LEN field of the last MAC subheader is removed. If no padding occurs in step 1015, since the MAC subheader is the last MAC subheader, in step 1025, the transmitter sets the E field of the last MAC subheader to '0' and the F field and the LEN of the last MAC subheader. Omit the field. On the other hand, by removing the F / LEN field of the last MAC sub-header in step 1015, if more than two bytes of padding occurs when the size of the LEN field is 7 bits, or more than 3 bytes of padding when the size of the LEN field is 15 bits If this occurs (i.e., checking if padding is greater than the sum of the size of the F field and the LEN field), the MAC subheader is no longer the last MAC subheader due to the addition of padding, so in step 1020 the transmitter sends the E field. Set to '1' and generate a MAC subheader according to a conventional procedure, generate a MAC subheader for the padding to be added and as much padding as necessary and store it as the actual last MAC SDU.

In step 1070, the transmitter generates a MAC header by combining the generated MAC subheaders, and proceeds to step 1075 to generate a MAC PDU.

Meanwhile, in step 1010, when the transmitter generates the last MAC subheader and removes the F field and the LEN field of the last MAC subheader, when the size of the LEN field is 7 bits, 1 byte of padding occurs or the LEN field. If the size of 15 bit is 1 byte or 2 bytes of padding occurs, go to step 1030.

In step 1030, the transmitter checks whether 1 byte padding has occurred in the condition of step 1010, and if 1 byte padding occurs, the transmitter proceeds to step 1035 to store the 1-byte dummy padding.

In step 1030, when the 1-byte padding does not occur, that is, when 2-byte padding occurs, in step 1040, the transmitter sets the E field of the last MAC subheader to '0' and sets F / F of the last MAC SDU. Omit the LEN field.

In step 1045, the transmitter checks whether there is a PHR among MAC control information stored in the MAC PDU, and if there is no PHR, the transmitter stores the MAC sub header and the PHR MAC control information for the PHR in step 1050. On the other hand, in step 1045, if there is a PHR already stored in the MAC PDU, the transmitter proceeds to step 1055 and checks whether a BSR exists among MAC control information already stored in the MAC PDU.

If the BSR does not exist in step 1055, the transmitter proceeds to step 1060 to store the MAC subheader and the short BSR MAC control information for the short BSR. In contrast, if the BSR and the PHR are already stored in the MAC PDU in step 1055, the transmitter proceeds to step 1065 and selects any of the short BSR or the PHR to store the corresponding MAC subheader and the MAC control information.

Then, as described above, in step 1070, the transmitter generates a MAC header by combining the generated MAC sub-headers. In step 1075, the transmitter completes generation of the MAC PDU.

11A and 11B are flowcharts illustrating a transmission operation according to an eighth embodiment of the present invention.

11A and 11B, in step 1105, the transmitter detects occurrence of a MAC PDU generation event. For example, when receiving the uplink transmission resource and the size of the MAC PDU from the base station scheduler, the UE recognizes that the MAC PDU corresponding to the size of the indicated MAC PDU should be generated, and the transmitter determines that the size of the MAC PDU is higher than the size of the indicated MAC PDU. By referring to the amount of data stored in the hierarchical buffer, logical channels for data transmission are determined, and the size of MAC SDU to be generated for each logical channel is determined. The remaining MAC subheaders except the last MAC subheader for each MAC SDU are generated according to a conventional procedure according to the size of the MAC SDU to be generated for each logical channel.

In step 1110, when the transmitter removes the F field and the LEN field of the last MAC subheader, it checks whether 1 byte of padding occurs when the size of the LEN field is 7 bits. If the size is 15 bits, it checks whether one or two bytes of padding occur (i.e., if padding is less than or equal to the sum of the size of the F field and the LEN field except the case of 0 byte padding).

As a result of checking whether the padding occurs, the process proceeds to step 1130 if the padding occurs, and the process proceeds to step 1115 otherwise.

In step 1115, the transmitter checks whether padding does not occur even if the F / LEN field of the last MAC subheader is removed. In step 1115, when the transmitter does not have padding, since the MAC subheader is the last MAC subheader, in step 1125, the transmitter sets the E field of the last MAC subheader to '0' and the F field of the last MAC subheader. Omit the and LEN fields. On the other hand, by removing the F / LEN field of the last MAC subheader in step 1115, if the size of the LEN field is 7 bits, more than 2 bytes of padding occurs, or if the size of the LEN field is 15 bits, more than 3 bytes of padding If this occurs (i.e., checking if padding is greater than the sum of the size of the F field and the LEN field), then the MAC subheader is no longer the last MAC subheader due to the addition of padding, so in step 1120 the transmitter sends the E field. Set to '1' and generate a MAC subheader according to a conventional procedure, generate a MAC subheader for the padding to be added and as much padding as necessary and store it as the actual last MAC SDU.

In step 1180, the transmitter generates a MAC header by combining the generated MAC subheaders, and in step 1185, generates a MAC PDU.

Meanwhile, in step 1110, when the transmitter removes the F field and the LEN field of the last MAC subheader, when the size of the LEN field is 7 bits, 1 byte of padding occurs or the LEN field is generated. If the size of 15 bit is 1 byte or 2 bytes of padding occurs, proceeds to step 1130.

In step 1130, the transmitter checks whether 1 byte padding has occurred in the condition of step 1110. When the 1 byte padding occurs, the transmitter proceeds to step 1135 to store the 1-byte dummy padding.

In step 1130, when the 1-byte padding does not occur, that is, when 2-byte padding occurs, in step 1140, the transmitter sets the E field of the last MAC subheader to '0' and the F of the last MAC SDU. Omit the / LEN field.

In step 1145, the transmitter determines whether a BSR exists among MAC control information already stored in the MAC PDU, and when the BSR does not exist, in step 1150, the transmitter receives the MAC subheader and the short BSR MAC control information for the short BSR. On the other hand, in step 1145, if there is already a BSR stored in the MAC PDU, the transmitter proceeds to step 1155 and checks whether the BSR already stored in the MAC PDU is a short BSR. In step 1155, if the BSR stored in the MAC is a short BSR, the transmitter proceeds to step 1160 in which the transmitter transmits a short BSR MAC subheader and short BSR MAC control information for an LCG different from the short BSR currently stored in the MAC PDU. To house. On the other hand, in step 1155, when the check result indicates that the already stored BSR is not a short BSR, that is, when the already stored BSR is a long BSR, the transmitter proceeds to step 1165 among the MAC control information already stored in the MAC PDU. Check that no PHR exists. If the PHR does not exist in step 1165, the transmitter receives the MAC subheader and PHR MAC control information for the PHR in step 1170. On the other hand, if the BSR and the PHR are already stored in the MAC PDU in step 1165, the transmitter selects one of the short BSR or the PHR in step 1175 to store the corresponding MAC subheader and the MAC control information.

Then, as described above, in step 1180, the transmitter generates the MAC header by combining the generated MAC subheaders. In step 1185, the transmitter completes generation of the MAC PDU.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

Claims (10)

A method of generating and transmitting a medium access control (MAC) protocol data unit (PDU) in a mobile communication system, the method comprising: Checking whether a size of TB allocated from a base station satisfies a predetermined specific condition when generating the MAC PDU; Generating a MAC PDU by excluding a BSR from the MAC PDU when the specific condition is satisfied; And transmitting the generated MAC PDU through a physical layer. An apparatus for generating and transmitting a medium access control (MAC) protocol data unit (PDU) in a mobile communication system, When generating the MAC PDU, it is checked whether the size of the TB allocated from the base station satisfies a predetermined specific condition, and if the specific condition is satisfied, a buffer status report (BSR) is excluded from the MAC PDU, and a MAC PDU is generated. MAC control unit to control to, A header generator for generating a header of a MAC PDU under the control of the MAC controller; At least one radio link control unit for generating and providing the MAC SDU; And a multiplexing unit which multiplexes the output of the radio link control unit and the output of the header generating unit under the control of the MAC control unit. A method of transmitting a medium access control (MAC) protocol data unit (PDU) in a mobile communication system, the method comprising: Generating a MAC header, wherein padding is added to omit the last F field and the LEN field for the last MAC SDU in generating a MAC PDU comprising each MAC SDU, wherein If the size of the padding is larger than that of the last F field and the LEN field, the last F field and the LEN field are not included in the MAC header and are omitted. Generating a MAC PDU by attaching the MAC header to a payload including each MAC SDU, and generating the MAC PDU. The method of claim 3, wherein the generating process, If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. A method for generating a medium access control protocol data unit in a mobile communication system, characterized by including size MAC control information. The method of claim 3 or 4, wherein the generating process If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. And including MAC control information of a size but not already stored in the MAC PDU. The method of claim 5, wherein the generating process, If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. And including MAC control information of a size, but including a short BSR if the BSR is not already stored in the MAC PDU. The method of claim 5, wherein the generating process, If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. And including the MAC control information of the size, but including the PHR if the PHR is not already stored in the MAC PDU. The method of claim 5, wherein the generating process, If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. And including MAC control information of a size but including a short BSR of another LCG when a short BSR is already stored in the MAC PDU. The method of claim 4 or 7, wherein the generating process, If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. And including the MAC control information of the size, but including the PHR when the BSR is already stored in the MAC PDU and the PHR is not stored in the MAC PDU. The method of claim 4 or 6, wherein the generating process, If the size of the total padding is not greater than the size of the last F field and the LEN field, the last F field and the LEN field are deleted from the MAC header and correspond to the sum of the sizes of the deleted last F field and the LEN field. And including a MAC control information of a size, but including a short BSR if a PHR is already stored in the MAC PDU and a BSR is not received.