Apparatus and method for generating mac pdu in a mobile communication system

The present invention relates to a mobile communication system, and particularly to an apparatus and method for generating and analyzing a medium access control (MAC) header with optimized information.

Mobile communication systems have evolved into high-speed, high-quality wireless data packet communication systems for providing data services and multimedia services as well as conventional voice services. Third generation using Wideband Code Division Multiple Access (hereinafter referred to as "CDMA") based on GSM (Global System for Mobile Communications) and GPRS (General Packet Radio Services), which are European systems. (3G) UMTS (Universal Mobile Telecommunication), a mobile communication system The Service) system provides a consistent service that allows mobile phone and computer users to transmit packet-based text, digitized audio or video data, and multimedia data anywhere in the world at high speeds of over 2 Mbps. This UMTS system can connect to any termination in the network by means of a packet-switched connection concept that uses a packet protocol such as Internet Protocol (IP). The 3GPP (3rd Generation Partnership Project), which is in charge of standardizing UMTS systems, is discussing LTE (Long Term Evolution) as a next-generation UMTS mobile communication system. LTE aims to realize high-speed packet communication of about 100 Mbps, and various measures are being discussed for that purpose. As an example, there is a technique of reducing the number of nodes on the communication path by simplifying the network structure or optimizing the radio protocol for the radio channel.

Figure 1 shows the functions of the MAC hierarchy of a conventional LTE mobile communication system. Referring to FIG. 1, in the transmitter, the first and second radio link control (Radio Link Control: hereinafter referred to as RLC) entities 102 and 104 indicate the RLC SDU (Service Data Unit) received from the upper layer. Each consists of one RLC PDU (Protocol Data Unit). MAC layer 106 transmits RLC PDUs to the receiver via physical (PHY) layer 108. At the receiver, the MAC layer 112 receives the RLC PDU via the PHY layer 110 and provides it to the associated RLC entities 114,116. These RLC entities 114,116 extract the RLC SDU and provide it to the upper hierarchy. The RLC PDU is analyzed as a MAC SDU at MAC hierarchy 106. The MAC layer 106 generates a MAC header and combines the MAC header with the MAC SDU to form one MAC PDU. MAC PDU is MAC received from RLC entities 102,104 In addition to the SDU, it can include a MAC SDU to control transmission and reception between the transmitter and receiver MAC layers 106,112. The MAC SDU for control can be transmitted with the MAC SDU for data transmission in the MAC PDU, or can be transmitted alone in the MAC PDU. Therefore, the header of the MAC PDU (hereinafter referred to as "MAC header") is configured so that the MAC SDU for data transmission can be distinguished from the MAC SDU for control.

Figure 2A shows the format of MAC PDUs in traditional mobile communication systems. Referring to FIG. 2A, a MAC PDU contains a MAC header 200 and a Payload 209,210,211 carrying one or more MAC SDUs. The MAC header 200 includes a logical channel identifier (LCID) field 201,204,207, an E field 202,205,208, and a length field 203,206. LCID 201,204,207 distinguishes MAC SDUs transmitted to various logical channels. E202,205,208 indicate the presence or absence of other multiplexed MAC SDUs, respectively. If E is 0, this means that the corresponding MAC SDU is the last MAC SDU. If E is 1, this means that the corresponding MAC SDU is followed by another multiplexed MAC SDU. In the latter case, the Length Field (LF) and LCID follow the E field. LF203,206 is the corresponding MAC Indicates the length of SDU. Therefore, these LF203,206 must be long enough to represent the length of the MAC SDU.

Here, the minimum unit of the multiplexed related information of the MAC header is referred to as a "sub-header". For example, the subheader for one MAC SDU is header information including LCID, E, and LF. In some cases, some of the subheaders may be omitted, or one MAC header may contain different forms of subheaders. The padding header, which will be described later, is treated as a sub-header that carries information about padding, even if it is not a sub-header for MAC SDU. Referring to FIG. 2A, in the MAC header 200, the first subheader 213 consisting of LCID201, E202, and LF203 is associated with the first MAC SDU209, and the second subheader 215 consisting of LCID204, E205, and LF206 is second. The third subheader 217, consisting of LCID207 and E208, is associated with the second MAC SDU210 and is associated with the third MAC SDU211. As can be seen from FIG. 2A, the third subheader 217 does not contain the LF. The reason is the MAC PDU size, or transport block (Transport). Block: TB) size is known for both transmitter and receiver, so the receiver subtracts the sum of the length of LF203,206 and the length of MAC header 200 from the TB size and the third MAC SDU211 The size of can be determined. Therefore, the LF is not required for the third MAC SDU211, and instead, other user data can be transmitted to the space of the LF, which increases the transmission efficiency.

However, for accurate transmission and reception of data, both the transmitter and receiver must know which MAC SDU is not included in the LF. There are usually two possible ways to provide this information. In the first method, the transmitter notifies the receiver of the location information of the absent LF. In the second method, the transmitter and receiver pre-promise the absence of LF in the subheader at a particular location. In particular, LF does not exist in the last subheader. However, the absence of LF in the last subheader causes the following problems. In general, MAC PDUs perform padding. In the padding of this MAC PDU, the padding bit (or dummy bit) is added to the free area of the TB in which the amount of transmission data is smaller than the predetermined TB size in order to match the TB with the predetermined TB size. To indicate this padding, a "padding subheader" is added to the header of the MAC PDU. If space remains after that, the payload will be padded.

The absence of the last LF causes the following problems when the padding size is less than or equal to the size of the last LF. Here, the last LF means LF for the last MAC SDU of one or more MAC SDUs included in the MAC PDU. If the TB size is set to 100 bytes and the last LF is 2 bytes, the absence of the last LF creates 2 bytes of free space in the TB that can carry additional data. When 1 byte of data is added, the required padding is 1 byte. Without additional data to be transmitted, the padding required would be 2 bytes. When the padding size is less than or equal to the length of the LF in this way, the following contradictions are faced. First, if the last LF is not included and 1 byte of data is added, 1 byte of padding is required. To indicate this padding, the padding subheader is bound to the MAC header so that it is no longer the last subheader. The last LF is not "LF for the last subheader" and must be omitted. After that, the last LF of 2 bytes must be included in the MAC header, but the problem arises that the size of the TB increases to 102 bytes. Therefore, there is a contradiction that the added 1-byte data and 1-byte padding should be deleted. Second, if the last LF is not included and there is no data to add, the padding required is 2 bytes. In this case as well, there is a problem that the above-mentioned contradiction occurs.

<p> Therefore, the present invention has been made in view of the above-mentioned problems as in the prior art, and an object thereof is an apparatus and method for generating a MAC PDU having an optimized MAC header in a mobile communication system, and a method. It is an object of the present invention to provide a device and a method for receiving and parsing the generated MAC PDU. Another object of the present invention is to provide a device and a method for clarifying whether or not the last LF is included in a MAC PDU in a mobile communication system, simplifying the MAC PDU configuration process, and increasing the data processing speed. There is. Another object of the present invention is to not include the last LF in the MAC header in order to optimize the MAC header in the mobile communication system, but if the required padding size is less than or equal to the size of the last LF, it is included in the MAC header. It is an object of the present invention to provide a device and a method for generating a MAC PDU, and a device and a method for receiving the MAC PDU.</p>

<p> In order to achieve the above object, according to one aspect of the present invention, there is a method of generating a MAC PDU in a mobile communication system, the step of confirming the LCID of the MAC SDU to be multiplexed, and the LCID. A step of determining the LF length for each MAC SDU with reference to a predetermined LF length, a step of generating a MAC header containing the LCID for the MAC SDU and the determined LF length, and a MAC SDU. It includes a step of generating a MAC PDU by combining a MAC header with a payload containing, and the step of generating a MAC header is for MAC PDU generation, assuming that the last LF of the MAC header is omitted. If the required padding size is greater than the length of the last LF, include the last LF in the MAC header, recalculate the required padding size taking into account the inclusion of the last LF, and padding with the recalculated padding size. Further provided with additional steps. If the required padding size is less than or equal to the length of the last LF, the last LF is included in the MAC header.</p><p> According to another aspect of the invention, it is a MAC PDU generator in a mobile communication system that provides a multiplexing MAC SDU to a multiplexer, confirms the LCID of the MAC SDU, and the length of the LF for each of the MAC SDUs. Determine the LCC, refer to the predetermined LF length for the LCID, and determine the LCC and the LCC entity for the MAC SDU with at least one RLC entity that provides the LCC and the determined LF length to the header generator. It includes a header generator that generates a MAC header containing the length of the LF and provides it to the multiplexer, and a multiplexer that multiplexes the MAC header with at least one MAC SDU, and the header generator is the last of the MAC headers. If the padding size required for a MAC PDU is greater than the length of the last LF, assuming the LF is absent, then include the last LF in the MAC header and take into account the inclusion of the last LF in the required padding size. Recalculate, add padding according to the recalculated padding size, and include the last LF in the MAC header. If the required padding size is less than or equal to the length of the last LF, the header generator will include the last LF in the MAC header.</p><p> Further, according to another aspect of the present invention, a method of parsing a MAC SDU from a MAC PDU in a mobile communication system, wherein the LCID of the MAC SDU multiplexed with the MAC PDU received from the MAC header of the MAC PDU is used. The step to check, the step to determine if the length of the MAC PDU calculated using the MAC header is the same as the known TB size, and the last LF associated with the last MAC SDU in the MAC header If the step of parsing the MAC SDU from the MAC PDU by the LF in the MAC header and the length of the MAC PDU is different from the TB size, it is determined that the last LF is not included in the MAC header. It comprises a step of parsing the MAC SDU from the MAC PDU by the last LF absent and the LF in the MAC header.</p><p> Further, according to another aspect of the present invention, a device that parses a MAC SDU with a MAC PDU in a mobile communication system, and the LCID of the MAC SDU multiplexed from the MAC header of the received MAC PDU to the MAC PDU. Includes a header detector that confirms and provides the SDU detector with the size of the MAC SDU multiplexed using a predetermined LF length for the LCID, and the SDU detector determines the LCID and MAC SDU size. If the length of the MAC PDU calculated using is the same as the known TB size, it is determined that the last LF associated with the last MAC SDU is included in the MAC header, and the LF in the MAC header determines that the MAC PDU is included in the MAC. If the SDU is parsed and the length of the MAC PDU is not the same as the TB size, it is determined that the last LF is not included in the MAC header, and the MAC SDU is removed from the MAC PDU by the last LF in the absence and the LF in the MAC header. Parsing.</p><p> According to another aspect of the present invention, a method of generating a MAC PDU in a mobile communication system, referring to a step of confirming the LCID of the MAC SDU to be multiplexed and a predetermined LF length for the LCID. To determine the length of the LF for each MAC SDU, to generate a MAC header containing the LCID for the MAC SDU and the determined length of LF, and to combine the MAC header into the payload containing the MAC SDU. It includes a step of generating a MAC PDU. The step to generate the MAC header is to include the last LF and the length indicator in the MAC header and the E field as the last LF if the required padding size is less than or equal to the sum of the last LF and the length of the length indicator. It further comprises a step of setting it to a value indicating that it includes a length indicator and setting it to a predetermined value indicating that the subheader containing the last LF is the last subheader.</p><p> Further, according to another aspect of the present invention, which is a MAC PDU generator in a mobile communication system, provides a multiplexing MAC SDU to a multiplexer, confirms the LCID of the MAC SDU, and LF for each MAC SDU. Determines the length of the LCC, refers to the predetermined LF length for the LCID, and determines the LCC entity for at least one RLC entity that provides the LCID and the determined LF length to the header generator, and the LCID for the MAC SDU. It includes a header generator that generates a MAC header containing the LF of the specified length and provides it to the multiplexer, and a multiplexer that multiplexes the MAC header with at least one MAC SDU. If the required padding size is less than or equal to the sum of the last LF and the length of the length indicator, the header generator will include the last LF and length indicator in the MAC header and include the E field as the last LF and length indicator. Set to a value indicating the inclusion of, and set to a predetermined value indicating that the subheader containing the last LF is the last subheader.</p><p> Further, according to another aspect of the present invention, it is a method of parsing a MAC SDU with a MAC PDU in a mobile communication system, and the LCID of the MAC SDU multiplexed in the MAC PDU from the MAC header of the received MAC PDU. And the step to check the E field in the MAC header, and when the E field is set to a given value that indicates the absence of the length indicator for the last LF and last LF associated with the last MAC SDU, it is absent. Includes a step to calculate the length of the last MAC SDU taking into account the last LF and length indicator of the, and a step to parse the MAC SDU from the MAC PDU using the LCID and the length of the last MAC SDU. ..</p><p> In addition, according to another aspect of the present invention, a device that parses a MAC SDU with a MAC PDU in a mobile communication system, wherein the MAC SDU multiplexed from the MAC header of the received MAC PDU into the MAC PDU. When the header detector, which checks the LCID and checks the E field of the MAC header, and the E field are set to a given value that indicates the absence of the length indicator for the last MAC SDU-related LF and the last LF, Includes an SDU detector that calculates the length of the last MAC SDU taking into account the last LF and length indicator in the absence and parses the MAC SDU from the MAC PDU using the LCID and the length of the last MAC SDU. ..</p>

<p> The present invention solves the problems related to MAC header generation and optimization by including the last LF in the MAC header when the padding size required to generate the MAC PDU is less than or equal to the length of the last LF. Has an effect. It also has the effect of increasing the data communication speed by shortening the generation time of MAC PDU.</p>

<figref num="1">It is a figure which shows the function of the MAC hierarchy in the conventional LTE mobile communication system.</figref><figref num="2A">It is a figure which shows the format of MAC PDU in the conventional mobile communication system.</figref><figref num="2B">It is a figure which shows the format of the MAC header by embodiment of this invention.</figref><figref num="3">It is a block block diagram which shows the MAC PDU generation part of the transmitter in the mobile communication system by embodiment of this invention.</figref><figref num="4">It is a block block diagram which shows the MAC PDU receiver part of the receiver in the mobile communication system by embodiment of this invention.</figref><figref num="5A">It is a flowchart which shows the operation which generates the MAC PDU which has a MAC header in the transmitter of the mobile communication system by embodiment of this invention.</figref><figref num="5B">It is a flowchart which shows the operation which generates the MAC PDU which has a MAC header in the transmitter of the mobile communication system by embodiment of this invention.</figref><figref num="5C">It is a flowchart which shows the operation which generates the MAC PDU which has a MAC header in the transmitter of the mobile communication system by embodiment of this invention.</figref><figref num="5D">It is a flowchart which shows the operation which generates the MAC PDU which has a MAC header in the transmitter of the mobile communication system by embodiment of this invention.</figref><figref num="5E">It is a flowchart which shows the operation which generates the MAC PDU which has a MAC header in the transmitter of the mobile communication system by embodiment of this invention.</figref><figref num="6A">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6B">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6C">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6D">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6E">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6F">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6G">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="6H">It is a flowchart which shows the operation which detects the MAC header and MAC SDU from MAC PDU in the receiver of the mobile communication system by embodiment of this invention.</figref><figref num="7">It is a figure which shows the format of the MAC PDU according to the embodiment of this invention.</figref><figref num="8">It is a flowchart which shows the transmission operation by embodiment of this invention.</figref><figref num="9">It is a flowchart which shows the receiving operation by embodiment of this invention.</figref>

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the attached figure, the same reference code and reference number are given to the same component or a component that is functionally similar. Reference numerals are used in detailed description to indicate various embodiments and various aspects and advantages of the present invention. Embodiments of the present invention are defined on the basis of claims and equivalents, and include various and detailed descriptions to aid understanding. However, these detailed explanations can only be considered as typical examples. Therefore, it is clear to those with ordinary knowledge in the art that various modifications and modifications of the invention described below are possible without departing from the scope and spirit of the invention. Specific description of known functions or configurations will be omitted for clarity and brevity. Embodiments of the present invention are 3GPP based on UMTS. Although described in the context of LTE systems, the MAC header configuration is also applicable to other mobile communication systems with similar technical backgrounds and channel configurations with minor modifications within the scope of the present invention. It is obvious to those who have ordinary knowledge in the technical field of the invention. Hereinafter, the present invention will be described with reference to the two embodiments. The first and second embodiments will be described with reference to FIGS. 2 to 6 and 7 to 9, respectively.

&lt;First embodiment&gt; Prior to the detailed description of the first embodiment according to the present invention, first, the main concept of this embodiment will be described. Configuring a MAC PDU goes through two major steps. One step is to arrange the MAC SDUs (ordering), and the other step is to generate MAC PDUs with the arranged MAC SDUs (PDU generation). It should be noted that in embodiments of the present invention, the padding size is compared to the length of the last LF only if the padding size is greater than 0, i.e. if padding is present. In other words, the present embodiment does not consider the case where there is no padding in the MAC PDU. For the optimization of the MAC header according to the embodiment of the present invention, LF and all other fields related to LF can be omitted. Therefore, although only the omission of LF will be described below, the present invention is not limited thereto, and it goes without saying that other fields related to LF can also be omitted.

The SDU sequence is described with reference to three embodiments of the invention that indicate a method for determining the LF length. In the first embodiment, the same LF length is set for each logical channel, in the second embodiment, different LF lengths are set for different logical channels, and in the third embodiment, the LF length is "TB size". Is set to the "minimum value required to represent". PDU generation depends on whether the required padding size is less than or equal to the length of the last LF. That is, the MAC PDU is configured in a different manner depending on whether the padding size exceeds the length of the last LF or does not exceed the above length. If the required padding size exceeds the last LF, it is recalculated taking into account the inclusion of the last LF, and the MAC PDU is padded with the recalculated padding size and generated to include the last LF. On the other hand, if the required padding size is less than or equal to the length of the last LF, one of the two embodiments can be considered to solve the situation. Depending on one embodiment of PDU generation, MAC The PDU is composed of the last LF. Five specific cases can be considered for this embodiment, which will be described later. In other embodiments of PDU generation, MAC PDUs are configured without a final LF. In particular, the MAC PDU is padded without the last LF and sets the Reserve: R field (or specific indicator) to a given value. The use of this R field is defined to indicate that "MAC PDU padded without last LF" and the size of the padding is represented by the value of the R field.

Hereinafter, embodiments of the SDU sequence according to the present invention will be described in detail. In the first embodiment of the SDU sequence, a fixed LF length is set and the MAC SDU is sequenced. Since each logical channel has the same LF length, MAC SDUs can be arranged without any special conditions. For example, SDUs are randomly arranged. In the second embodiment of the SDU sequence, the LF length is based on the logical channel. The amount of data varies depending on the logical channel that transmits the data in the mobile communication system. The amount of data transmitted to the logical channel is based on the characteristics of the logical channel, and different LF lengths are set to different logical channels in the MAC header configuration. From the side of the MAC header, the LF length depends on the LCID. The subheader with the longest LF and the MAC SDU described by this subheader are then placed at the end of the MAC header and the last payload, respectively. When the MAC PDU is configured without the last LF, the absence of the longest LF increases transmission efficiency, thereby optimizing the configuration of the MAC PDU. A third embodiment of the SDU sequence features an LF length based on the TB size set to the "minimum required to represent the TB size". MAC headers can be configured efficiently by preventing unnecessary resource consumption. The MAC SDU sequence is carried out by the generation of PDUs, which will be described later.

To determine if a MAC PDU has been padded, the padding size required to generate a MAC PDU is calculated, assuming the absence of an LF (ie, the last LF) for the last subheader in the array. The calculated padding size is then compared to the length of the last LF. The comparison result will be explained in two parts. One is when the padding size exceeds the last LF, and the other is when the padding size is less than or equal to the length of the last LF. In the first result, if TB is 100 bytes, the sum of the lengths of the arrayed MAC SDU and the subheader is 99 bytes, and the last LF is 1 byte, the absence of this last LF causes the sum. Is 98 bytes. If there is no additional data to be transmitted at the last LF position, 2 bytes is free space, so the required padding size is 2 bytes. Therefore, the required padding size (2 bytes) exceeds the length of the last LF (1 byte). In this case, the required padding size is recalculated taking into account the inclusion of the last LF, and the MAC header is generated to include the padding header by the recalculated padding size. In the above example, the sum of the lengths of the SDU including the last LF and the subheader is 99 bytes. After that, the recalculated padding size is 1 byte. Ultimately, the required padding size is determined to be 1 byte, and the MAC PDU is configured to include a MAC header with a padding header depending on the final padding size. In the second case where the required padding size is less than or equal to the length of the last LF, the TB is 100 bytes, the size of the transmitted data including the MAC header and payload is 100 bytes, and the last LF is 2 bytes. If there is, and the data transferred to the last LF position is 1 byte, the required padding size is 1 byte, assuming the last LF does not exist. That is, the required padding size is less than or equal to the length of the last LF.

As mentioned above, the first and second embodiments of PDU generation are available in the above cases. The choice between them is based on the system implementation. The first embodiment of PDU generation is characterized in that the MAC PDU is configured to include the final LF without padding. In the above example, the MAC PDU contains the last LF, so it consists of a 100-byte MAC header and payload. Five specific cases for MAC PDU generation are described in more detail with reference to Figure 5D. MAC PDUs, on the other hand, are generated by padding without the final LF. It should be noted here that, in order to resolve the inconsistencies faced by the prior art, the last LF-less padding is represented to the receiver by setting the R field to a predetermined value. For reference, the R field is a field defined as one of the MAC headers in the 3GPP standard, but its use has not yet been specified. In other embodiments, instead of the R field, a particular indicator can be inserted in the MAC header for the same purpose. For example, if the last LF is 2 bytes and 1 byte of data is added, the absence of the last LF and the addition of 1 byte of data will result in 1 byte of space. This 1-byte space is filled with padding subheaders. In this case, the R field of the existing last subheader before the padding subheader is set to an appropriate value representing the total padding size including the length of the padding subheader.

In an embodiment of the invention, the R field is defined to indicate that "MAC PDU is combined with the padding header without the last LF", and the number of bits in this R field can indicate the padding size. This is possible because the padding size is less than or equal to the length of the last LF. As an example, the padding size can be displayed using 2 bits of a 1-byte R field. FIG. 2B shows the configuration of a MAC header having an R field according to an embodiment of the present invention. FIG. 2B shows the format of a MAC header with an R field according to an embodiment of the present invention. Referring to FIG. 2B, the MAC header includes LCID231, E232, R233, and length (ie, LF) 234.

The apparatus according to the embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a block configuration diagram showing a MAC PDU generator of a transmitter in a mobile communication system according to an embodiment of the present invention. Referring to FIG. 3, the MAC PDU generator includes a multiplexer (MUX) 300, RLC entities 302,304,306, a MAC control unit 308, and a header generator 310. The RLC entities 302, 304, and 306 send their respective MAC SDUs to the MUX300, and send the LCID and LF values associated with the MAC SDUs to the header generator 310. When there is a MAC SDU that carries the control signal used to control the MAC protocol, the MAC control unit 308 sends the control MAC SDU to the MUX300 and sends the LCID and LF values related to the control MAC SDU to the header generation unit. Send to 310. The length of the LF can be set in a different manner depending on the embodiment of the present invention. More specifically, in the first embodiment, the LFs have the same length, the subheader and the MAC. SDUs are arranged. In the second embodiment, the LF has different lengths depending on the logical channel associated with each. In a third embodiment, the LF has the minimum length required to represent the TB size.

The header generation unit 310 generates a MAC header having an LCID and an LF value received from the RLC entities 302, 304, 306 and the MAC control unit 308. The header generation unit 310 provides the MAC header to the MUX300 and controls the arrangement order of the MAC SDU through the MUX300. More specifically, the header generator 310 can control the MUX300 to sequence the MAC SDU by the first embodiment of the SDU sequence, and the longest LF by the second or third embodiment of the SDU sequence. You can control the MUX300 so that the MAC SDUs that correspond to are arranged in the last payload. Further, the header generation unit 310 generates a MAC header by combining the sub-headers according to the arrangement order of the MAC SDU, and transmits the MAC header to the MUX 300. As mentioned above, MAC PDU generation is based on whether the padding size required to configure the MAC PDU is greater than the length of the last LF, or less than or equal to the length of the last LF. If the required padding size is longer than the length of the last LF, the required padding size will be recalculated and the MAC will take into account the inclusion of the last LF. The PDU consists of the recalculated padding size. On the other hand, if the required padding size is less than or equal to the length of the last LF, the first or second embodiment of PDU generation described above is used. The MUX300 multiplexes the MAC header and the MAC SDU according to the arrangement order of the MAC SDU according to each embodiment, and provides the generated MAC PDU to the PHY hierarchy.

FIG. 4 is a block configuration diagram showing a MAC PDU receiver in the mobile communication system according to the embodiment of the present invention. Referring to FIG. 4, the MAC PDU receiver includes a header detector 400, an SDU detector 402, an RLC entity 404, and a MAC control unit 406. The header detector 400 detects the length of the LCID and MAC SDU multiplexed on the received MAC PDU from the MAC header of the MAC PDU. The length of the MAC SDU can be found in the LF of the MAC header. Also, the LFs have the same length in the first embodiment. LFs have different lengths based on their associated logical channels. The longest LF subheader is located at the end of the MAC header. In a third embodiment of the invention, the LF is the minimum length required to represent the TB size. Received MAC The PDU contains recalculated padding, taking into account the inclusion of the last LF, if the required padding size calculated assuming the absence of the last LF exceeds the length of the last LF. On the other hand, if the required padding size is less than or equal to the length of the last LF, the first embodiment of PDU generation includes the last LF, and the second embodiment of PDU generation includes the padding and R fields without the last LF. including. The SDU detector 402 extracts the MAC SDU from the MAC PDU based on the LCID and MAC SDU length information received from the header detector 400, and the MAC SDU data is provided to RLC entity 404 for data control. The MAC SDU is provided to MAC control unit 406. This operation will be described in more detail with reference to FIGS. 6A to 6H.

Hereinafter, the operation of generating a MAC PDU on the transmitting side according to the embodiment of the present invention will be described. 5A to 5E are flowcharts showing a MAC PDU generation operation of the transmitter in the mobile communication system according to the embodiment of the present invention. In particular, FIGS. 5A, 5B, and 5C show the SDU sequence operation according to the first to third embodiments of the SDU sequence, respectively. In addition, FIGS. 5D and 5E show the operation for the generation of the MAC header and the configuration of the MAC PDU according to the first and second embodiments of the PDU generation, respectively. The above operation is shown in FIGS. 5A, 5B, and 5C.

Referring to FIG. 5A showing the first embodiment of the SDU sequence, the transmitter has a fixed length of LF upon detecting the occurrence of a MAC PDU generation event in step 501 without any additional processing on the MAC header. Proceed to the procedure in Figure 5D or Figure 5E, taking into account the format of the MAC header. Referring to FIG. 5B showing a second embodiment of the SDU sequence, the transmitter detects the occurrence of a MAC PDU generation event in step 503, determines the LF length for each logical channel in step 505, and finally. Arrange the MAC SDU indicated by the subheader and the subheader with the longest LF at the end of the MAC header in the payload of. The transmitter then proceeds to the procedure of FIG. 5D or FIG. 5E. Referring to FIG. 5C showing a third embodiment of the SDU sequence, the transmitter is requested in step 507 to represent the TB size for each logical channel when it detects the occurrence of a MAC PDU generation event in step 507. Determine the minimum LF length to be and the MAC indicated by the subheader in the last payload Arrange the subheaders with the longest LF at the end of the SDU and MAC headers. The transmitter then proceeds to the procedure of FIG. 5D or FIG. 5E.

Referring to FIG. 5D, in step 511, after the transmitter performs the SDU sequence operation according to the first to third embodiments, the padding size required to configure the MAC PDU is less than or equal to the length of the last LF. Judge whether or not. If the required padding size is greater than the length of the last LF, the transmitter proceeds to step 517. At step 517, the transmitter recalculates the required padding size, taking into account the inclusion of the last LF. The transmitter then configures the MAC header, including the padding header, with the recalculated padding size in step 513. On the other hand, in step 511, if the padding size is less than or equal to the length of the last LF, the transmitter configures the MAC header containing the last LF in step 513 according to the first embodiment of PDU generation. At step 515, the transmitter generates a MAC PDU by multiplexing with at least one MAC SDU that carries the MAC header.

The next five cases are described by the first embodiment of PDU generation. Case 1: MAC PDU is generated with the last LF without padding. Case 2: If there is an extra hold bit in the MAC header, set it to a value that indicates that this extra hold bit contains the last LF. Case 3: MAC PDU contains the last LF and sets the E field corresponding to the last MAC SDU to '1' which indicates the inclusion of the last LF. This E-field setting has a different meaning from the conventional E-field described with reference to FIG. 2A. Case 4: The MAC PDU contains the last LF set in a pattern that indicates the inclusion of the last LF. For example, the last LF is all set to 0 to indicate the existence of the last LF. Case 5: The MAC PDU contains the last LF set in the pattern indicating the inclusion of the last LF, and the E field corresponding to the last MAC SDU is set to '1'. This case 5 is a combination of case 3 and case 4. In Cases 4 and 5, the pattern of the last LF means that the last LF is all set to 0. That is, if the last LF is 7 bits long, it can be '0000 000', and if the last LF is 15 bits long, it can be '0000 0000 0000 000'. Of course, the above pattern may be set to another value by prior consent.

Referring to FIG. 5E, the transmitter is the last LF padding size required to configure the MAC PDU in step 521 after the SDU sequence operation according to the first to third embodiments of the SDU sequence has been performed. It is determined whether or not it is less than or equal to the length of. If the required padding size is greater than the last LF size, the transmitter proceeds to step 531. At step 531 the transmitter recalculates the required padding size taking into account the inclusion of the last LF. The transmitter then constructs a MAC header in step 527 that includes a padding header with the final LF and the required padding size recalculated. On the other hand, if the padding size required in step 521 is less than or equal to the length of the last LF, the transmitter configures the MAC header in step 523 with the R field without the last LF. This R field is set to mean "the last LF is not included, but the padding header is added", and its value indicates the padding size. At step 525, the transmitter is MAC Pad the PDU. The transmitter then generates a MAC header containing the padding header in step 527 without the final LF. Steps 523-527 are based on the second embodiment of PDU generation. At step 529, the transmitter generates a MAC PDU by multiplexing with at least one MAC SDU that sends the MAC header.

Hereinafter, MAC PUD reception of the receiver according to the embodiment of the present invention will be described. Receiving a MAC PDU includes a confirmation step to determine the LF length of the header, an SDU pershing step to determine if the last LF is included, and thereby parsing the MAC SDU. .. In the header confirmation step, the LCID and LF lengths are determined by the MAC header of the received MAC PDU. To determine the length of the LF, the receiver operates corresponding to the first to third embodiments of the SDU sequence of the transmitter. For convenience, the operations corresponding to the first to third embodiments of the SDU sequence are referred to as the first to third embodiments of header confirmation. The SDU pershing step corresponds to the PDU generation operation of the transmitter. The present invention proposes a fifth embodiment for determining whether or not the last LF is included in the SDU Pershing step. This fifth embodiment is referred to as the first to fifth embodiments of SDU Pershing. According to an embodiment of the invention, a MAC is used to determine if the last LF is included in a MAC PDU. The length of the PDU is determined assuming that the last LF is included. If the length of the MAC PDU is the same as the known TB size, the receiver determines that the last LF is included. On the other hand, if the lengths are different, the receiver determines that the last LF is not included. In particular, the second embodiment of SDU Pershing corresponds to the second embodiment of PDU generation in which it can be determined from the R field of the MAC PDU whether or not the last LF is included in the MAC PDU.

6A to 6H are flowcharts showing the detection operation of the MAC SDU of the receiver in the mobile communication system according to the embodiment of the present invention. 6A, 6B, and 6C show the operations shown in FIGS. 5A, 5B, and 5C, respectively, that is, the reception operations corresponding to the first to third embodiments of header confirmation. FIG. 6E shows the reception operation corresponding to FIG. 5E. FIG. 6D shows the receiving operation corresponding to the cases 1 and 2 shown in FIG. 5D, FIG. 6F shows the receiving operation corresponding to the case 3 shown in FIG. 5D, and FIGS. 6G and 6H show the receiving operation corresponding to the case 4 and the case 2, respectively. The reception operation corresponding to Case 5 is shown. The receiving operation shown in FIGS. 6E to 6H is based on the first to fifth embodiments of SDU Pershing.

Referring to FIG. 6A showing the first embodiment of header confirmation, the receiver receives the MAC PDU in step 601 and confirms the LCID and fixed LF length in the MAC header of the MAC PDU in step 603. Then, the procedure shown in one of FIGS. 6D to 6H is performed. Referring to FIG. 6B showing a second embodiment of header confirmation, the receiver receives the MAC PDU in step 605, confirms the LCID in the MAC header of the MAC PDU in step 607, and determines by LCID in step 609. Check the length of LF. The receiver then proceeds with the procedure shown in one of FIGS. 6D-6H. Referring to FIG. 6C showing a third embodiment of header verification, the receiver receives the MAC PDU in step 611 and in step 613 the minimum value required to represent the TB size in the MAC header of the MAC PDU. Check the length of LF set in, and check the LCID in the MAC header in step 615. The receiver then proceeds with the procedure shown in one of FIGS. 6D-6H.

Referring to FIG. 6D showing a first embodiment of SDU Pershing corresponding to Cases 1 and 2 by the first embodiment of PDU generation, the receiver has not yet confirmed in the MAC PDU in step 621. Determine if there are other multiplexed MAC SDUs. In the presence of the MAC SDU, the receiver proceeds to one of the steps shown in Figures 6A, 6B, and 6C, as indicated by reference numeral B, and sees the subheaders for all MAC SDUs in the MAC header. Repeat until you do. Upon completing the verification of the subheaders for all MAC SDUs in step 621, the receiver proceeds to step 623. At step 623, the receiver calculates the length of the MAC SDU using all the LF values in the MAC header, assuming that the last LF is contained in the MAC PDU, to the length of the MAC PDU. Calculate the overall size of the MAC PDU based on it. The sum of all LF values is the sum of the MAC SDU length and the MAC header length, which can be seen from the LF length. The receiver then compares the size of the MAC PDU with the known TB size. MAC If the size of the PDU is the same as the TB size, the receiver determines in step 625 that the MAC PDU contains the last LF and in step 627 uses the LF to extract each MAC SDU from the MAC PDU. At step 629, the receiver processes the MAC SDU extracted by its LCID. On the other hand, if it is determined in step 623 that the size of the MAC PDU is different from the TB size, the receiver determines in step 631 that the MAC PDU does not contain the last LF. The reason the two values are different is to confirm that LF, assuming that the last LF is included, even though the last LF is omitted. At step 627, the receiver uses the LF to extract the MAC SDU and calculates the length of the MAC SDU based on the value of the existing LF and the TB size to determine the MAC SDU corresponding to the omitted LF. Extract. The receiver then processes the MAC SDU by each LCID in step 629. If the last LF is not included, it determines that the remaining payload of the MAC PDU since the previously extracted MAC SDU belongs to the last MAC SDU.

With reference to FIG. 6E, which shows the second embodiment of SDU Pershing, corresponding to FIG. 5E, which shows the second embodiment of PDU generation, the receiver is in step 641 and the E field for MAC SDU is '1'. Judges whether or not it is set to. If the E field is '1', the receiver determines that there are more multiplexed MAC SDUs in the received MAC PDU, and of FIG. 6A, FIG. 6B, and FIG. 6C represented by reference numeral B. Proceed to one procedure and repeat the operation until you see all the MAC SDU subheaders defined in the MAC header. If the E field is set to '0', which means that there are no more multiplexed MAC SDUs since the MAC SDU, the receiver will determine if the MAC header contains the last LF. Proceed to step 643. At step 643, the receiver determines if the R field (or other indicator) has been set. As mentioned earlier, if the required padding size exceeds the length of the last LF, the R field will be MAC. This means that the PDU does not contain the last LF, but does include padding. Therefore, when the R field is set, the receiver determines the padding size via the value of the R field in step 649. To do. In step 645, the receiver extracts the MAC SDU from the MAC PDU considering the LF value, padding size, and TB size, and in step 647, processes the MAC SDU by each LCID. Alternatively, if it is determined that the R field is not set, that is, for example, if all the R fields are initial values of '0', the receiver will set the value of LF in step 645 without going through step 649. Taking into account, the MAC SDU is extracted from the MAC PDU, and in step 647, the MAC SDU is processed by the LCID.

Referring to FIG. 6F showing a third embodiment of SDU parsing corresponding to Case 3 of FIG. 5D by the first embodiment of PDU generation, the receiver has the E field for MAC SDU set to '1'. Then, in step 651, it is determined that LF exists for MAC SDU, and in step 652, LF is used to calculate the size of MAC SDU. Given the previously accumulated size of the MAC PDU, the receiver updates this cumulative size by adding the calculated MAC SDU size and the MAC header size to the pre-cumulative size. At step 653, the receiver compares the updated cumulative size with the known TB size. If this cumulative size is determined to be the same as the TB size, the receiver determines in step 654 that the last LF is included in the MAC PDU and in step 656 using the value of the LF from the MAC PDU to the MAC. Extract SDU. At step 657, the receiver has the MAC extracted by its LCID. Handle SDU. On the other hand, if it is determined that the cumulative size is different from the TB size, the receiver returns to the procedure shown in one of FIGS. 6A, 6B and 6C, as represented by reference numeral B. If in step 651 the E field for the MAC SDU is determined to be '0', the receiver determines in step 655 that the LF is not included for the MAC SDU and has previously confirmed the MAC SDU. Except for, it is determined that the remaining MAC PDU belongs to the last MAC SDU, and in step 656, the LF is used to extract the MAC SDU from the MAC PDU. The receiver processes the MAC SDU extracted by its LCID in step 657. When the reception of the MAC PDU is completed, the cumulative size is reset to update the cumulative size for the next MAC PDU.

Referring to FIG. 6G showing a fourth embodiment of SDU parsing corresponding to Case 4 of FIG. 5D according to the first embodiment of PDU generation, the receiver has the E field for MAC SDU set to '0'. Then, it is determined that the MAC SDU corresponding to the E field is the last MAC PDU, and in step 663, it is confirmed whether or not the LF following the E field is set to the predetermined pattern. When the LF has a predetermined pattern, the receiver determines that the padding size required for MAC PDU generation is less than or equal to the length of the last LF, and the transmitter transmits the last LF set to the predetermined value. judge. In one embodiment, if the last LF is 7 bits, the predetermined pattern can be '0000 000'. The receiver determines that the last LF is included in the MAC PDU in step 665, extracts the MAC SDU from the MAC PDU using the LF of the MAC SDU in step 667, and processes the MAC SDU by LCID in step 669 ( Receiving behavior for Case 4 in Figure 5D). On the other hand, if the LF value is different from the predetermined pattern, the receiver will take step 671 and the last LF will be MAC. It is determined that it is not included in the PDU, the MAC SDU is extracted from the MAC PDU using the LF of the MAC SDU in step 667, and the MAC SDU extracted by the LCID is processed in step 669. At this time, the last MAC SDU is determined to occupy the rest of the MAC PDU payload after the previously extracted MAC SDU. If the E-field for the MAC SDU is determined to be '1' in step 661, the receiver is shown in one of FIGS. 6A, 6B, and 6C, as represented by reference numeral B. Go back to and repeat until you see the subheaders for all MAC SDUs in the MAC header.

Referring to FIG. 6H showing a fifth embodiment of SDU Pershing corresponding to Case 5 of FIG. 5D according to the first embodiment of PDU generation, the receiver has the E field for MAC SDU set to '1'. Then, in step 681, it is determined that LF exists for MAC SDU, and in step 683, the pattern of LF is confirmed. If the LF is the same as the given pattern, the receiver determines that the padding size required to generate the MAC PDU is less than or equal to the length of the last LF, the transmitter sets the E field to '1', and the MAC It is determined that the LF of the MAC SDU is set to a predetermined pattern to indicate the existence of the LF for the SDU. Therefore, the receiver determines that the last LF is included in the MAC PDU in step 685, extracts the MAC SDU from the MAC PDU using the LF of the MAC SDU in step 687, and processes the MAC SDU by LCID in step 689. (Reception operation for case 5 in Figure 5D). On the other hand, if it is determined that the LF pattern is different from the predetermined pattern, the receiver will MAC in step 687. Check the LF for use in extracting the SDU, go back to the procedure shown in one of Figure 6A, Figure 6B, and Figure 6C as represented by reference numeral B, and in the MAC header you can see all the MAC SDU subheaders. Repeat the operation until you confirm it. If the E field for the MAC SDU is '0' in step 681, the receiver determines in step 691 that the LF is not included for the MAC SDU and uses the LF in the MAC SDU in step 687. Extract the MAC SDU from the MAC PDU and process the MAC SDU extracted by that LCID in step 689. If the last LF is not included, the last MAC SDU is determined to occupy the rest of the MAC PDU excluding the previously extracted MAC SDU in the payload of the MAC PDU.

&lt;Second embodiment&gt; FIG. 7 shows the format of the MAC PDU according to the second embodiment of the present invention. Referring to FIG. 7, a MAC PDU contains a plurality of MAC subheaders 705,710 and a plurality of payloads 715,720 carrying multiple MAC SDUs or multiple MAC control information. Each MAC subheader 705 or 710 provides multiplexing information for the MAC PDU or MAC control information 715 or 720. A MAC PDU has as many payloads as there are MAC subheaders. The mapping relationship between the MAC subheader 705,710 and the payload 715,720 is based on the order of the payload 715,720. For example, the first and second MAC subheaders 705,710 represent the first and second payloads 715,720, respectively. Each MAC subheader contains LCID725, E730, flag F745, length (ie, LF) 750, and R735,740. LCID725 is the corresponding MAC Provides the ID of the logical channel that carries the SDU, or indicates the type of MAC control information that corresponds. E730 indicates whether the MAC subheader is the last subheader, and LF745 indicates the length of the MAC SDU or MAC control information. To reduce the processing load on the transmitter and receiver, the MAC subheaders 705 and 710 are byte-aligned, for which the 2-bit R field 735,740 is used. The LF750 is 7 or 15 bits and the leading F field 745 indicates the length of the LF750. For example, if the F field 745 is set to 0, the LF750 is 7 bits, and if the F field 745 is set to 1, the LF750 is 15 bits. If the LF750 is 7 bits, the LF750 can display up to 127 bytes in length, and if it is 15 bits, the LF750 can display up to 32768 bytes in length.

As shown in FIG. 7, the length of the MAC subheader is 1, 2 or 3 bytes. The length of the last MAC subheader is usually 1 byte because the LF and F fields are not included in the last MAC subheader. As mentioned earlier, if the absence of an LF in the last MAC subheader triggers a padding of 1 or 2 bytes, it is desirable to include the last LF. 1 or 2 byte padding occurs when the required padding size is less than or equal to the sum of LF and F lengths, and 1 or 2 byte padding occurs when the required padding size is greater than or equal to the sum of LF and F lengths. It can be said in general that it occurs in some cases. Below, for perfection, it is not determined whether the required padding size is greater than the sum of the lengths of LF and F, but whether the required padding size is 1 or 2 bytes. To do. Therefore, in the second embodiment of the present invention, the length of the last LF is determined by whether or not the padding size is 1 byte or 2 bytes in the removal of the last LF. The LF of the last MAC subheader is the last MAC with the corresponding MAC SDU Set to a value indicating that it is an SDU. The reason is that 2 bytes are available for the last MAC subheader, but the length of the last MAC SDU can exceed the maximum value represented by the LF of the 1-byte MAC subheader. For example, if a 1000 byte MAC PDU transfers a 196 byte first MAC SDU and an 800 byte second MAC SDU, the first MAC subheader is 2 bytes and the LF is from the second MAC subheader. When removed, that is, the last MAC subheader has a total MAC PDU size of 999 bytes, so 1 byte of padding is required. If the last MAC subheader contains an LF, only 7 bits are available for the last LF, but there is the problem that 15 bits are needed to represent a length of 800 bits. In order to solve the above problems, the transmitter and the receiver promise in advance the LF value representing the last MAC subheader. If the absence of F and LF in the last MAC subheader causes 1 or 2 bytes of padding, an LF with a size corresponding to the expected padding size will be inserted in the last MAC subheader and this LF will be set to the above value. This allows the receiver to correctly demultiplex the MAC SDU.

FIG. 8 is a flowchart showing a transmission operation according to the embodiment of the present invention. Referring to FIG. 8, at step 805, the transmitter senses the occurrence of a MAC PDU generation event. For example, when a mobile terminal (MS) transmitter receives information about reverse transmission resources and MAC PDU size from a base station (BS) scheduler, it recognizes that a MAC PDU of MAC PDU size is generated. At step 810, the transmitter refers to the size of the MAC PDU and the amount of data buffered in the upper tier buffer to determine the logical channels to carry the data and to determine the size of the MAC SDU for each logical channel. .. The transmitter generates the remaining MAC subheaders for each MAC SDU, excluding the last MAC subheader, in a general way.

Then, in step 815, if it is determined that the transmitter produces the last MAC subheader, then in step 820, whether the absence of F and LF in the last MAC subheader causes 1 or 2 bytes of padding. judge. As a result, if 1 or 2 bytes of padding occur, the transmitter proceeds to step 835, otherwise it proceeds to step 825. In step 825, the transmitter determines that padding does not occur even if the F and LF of the last MAC subheader are removed, so the E field of the last MAC subheader is set to '0'. The transmitter then completes the generation of this last MAC subheader in step 830 by removing the F and LF of the last MAC subheader. The value of this E field has the following meaning. 1: F and LF exist in the MAC subheader. When LF is set to a given value, for example '0000 000' or '0000 0000 0000 000', the MAC subheader is the last MAC subheader and is the MAC control information or MAC. SDU follows the MAC subheader. If LF is not a given value, the MAC subheader is followed by another MAC subheader. 0: MAC subheader is the last MAC subheader and does not contain F and LF. This MAC subheader is followed by MAC control information or MAC SDU.

The transmitter determines that the last F and LF are included because the removal of the last F and LF causes 1 or 2 bytes of padding. Therefore, the transmitter sets the E field in '1' to indicate the inclusion of F and LF in the last MAC subheader in step 835, and in step 840 the removal of the last F and LF causes 1 byte padding. Determine whether to generate 2-byte padding. The transmitter proceeds to step 845 for 1-byte padding and to step 855 for 2-byte padding. At step 845, the transmitter sets F to '0', which indicates that the length of the LF is 7 bits. The transmitter then sets the LF to a predetermined value, eg '0000 000', in step 850. In step 855, the transmitter sets F to '1', which indicates that the length of LF is 15 bits, and in step 860, sets LF to a predetermined value, for example, '0000 0000 0000 000'. Predetermined value '0000 000' or '0000 0000 0000 000'indicates that the MAC subheader is the last MAC subheader, and this MAC subheader is followed by MAC SDU or MAC control information. When the settings for all the fields of the MAC subheader are completed, the transmitter generates a MAC PDU in which the MAC subheader and the MAC SDU are concatenated in step 865 and transmits it to the receiver via the lower layer. In the present invention, since the transmitter according to the second embodiment can be easily realized from the transmitter according to the first embodiment described above, detailed description thereof will be omitted.

FIG. 9 is a flowchart showing a reception operation according to the embodiment of the present invention. Referring to FIG. 9, the receiver receives the MAC PDU through the lower hierarchy in step 905 and decodes and analyzes the MAC subheader of the MAC PDU in step 910. This MAC subheader is parsed in the order in which it is forwarded to the MAC PDU. For each MAC subheader, the receiver determines in step 915 whether the E field of the MAC subheader is '0'. Here, '0' means that the MAC SDU represented by the MAC header is the last MAC SDU, and this MAC subheader does not contain F and LF. If the E field is '0', the receiver in step 925 takes the MAC SDU by subtracting the sum of the lengths of the other MAC subheader and other MAC SDU or MAC control information from the overall size of the MAC PDU. Determine the size of. At step 930, the receiver demultiplexes the MAC PDU according to the LCID of the MAC subheader and the calculated size of the MAC SDU to extract the MAC SDU from the MAC PDU. If the E field is determined to be '1', the receiver determines in step 920 whether the LF of the MAC subheader is a given value, eg, '0000 000' or '0000 0000 0000 000'. .. Here, '1' indicates whether the MAC subheader contains F and LF, and the value of LF indicates whether the next byte of the MAC subheader belongs to another MAC subheader or MAC SDU / MAC control information. means. If the LF is the MAC subheader is the last MAC subheader and thereby the predetermined value for which the length of the last MAC SDU must be calculated, the receiver calculates the length of the last MAC SDU in step 925. Then, in step 930, the last MAC SDU is extracted from the MAC PDU by the length of the last MAC SDU. The receiver then finishes processing the MAC PDU. If LF is not a given value, the MAC subheader is not the last MAC subheader, and LF represents the length of the corresponding MAC SDU. Therefore, in step 935, the receiver uses the LCID, F, and LF of the MAC subheader to MAC from the MAC PDU. Extract the SDU and return to step 910 to process the next MAC subheader. In the present invention, the receiver according to the second embodiment can be easily realized from the receiver according to the first embodiment described above, and thus detailed description thereof will be omitted.

Although the present invention has been illustrated and described with respect to specific embodiments, various changes in form and details are possible without departing from the spirit and scope of the present invention as defined by the appended claims. It is clear to those with ordinary knowledge in the art.

300 Multiplexer (MUX) 302,304,306 RLC entity 308 MAC control unit 310 Header generator 400 header detector 402 SDU detector 404 RLC entity 406 MAC control unit