KR20020014971A - Apparatus and method for determining paging alert mode in a mobile communication system - Google Patents

Abstract

PURPOSE: An RLC(Radio Link Control) device is provided to concatenate at least two service data units received from an upper layer to generate protocol data units, to transmit the protocol data units to a lower layer by an RLC transmission mode, so that the lower layer can transmit at least two separated service data units to the upper layer by analyzing protocol data units composed of the two service data units. CONSTITUTION: A transmission RLC(Radio Link Control) layer(510) comprises as follows. An SDU(Service Data Unit) receiver(512) receives SDUs from an upper layer to distribute the SDUs to a corresponding processing block. An SDU segmentation block(513) segments the SDUs to the maximum size of RLC PDU(Protocol Data Unit) for transmissions. An SDU concatenation block(514) concatenates at least two SDUs provided from the SDU receiver(512) to the maximum size of RLC PDU for transmissions. A framer(515) frames the SDUs to RLC PDUs for transmissions. A transmission buffer(516) temporarily stores RLC PDU frames, and transmits the RLC PDU frames to a lower layer. A receiving RLC layer(520) comprises as follows. A receiving buffer(526) temporarily stores the RLC PDU frames. A reverse framer(525) accesses the RLC PDU frames to perform a reverse framing process for the RLC PDU frames. An SDU re-assembly block(523) assembles at least two SDUs of the reverse framer(525) to one SDU to output the one SDU. An SDU separator(524) separates the one SDU to output the separated SDUs. An SDU transmitter(522) transmits the SDUs of the reverse framer(525), the SDU re-assembly block(523), or the SDU separator(524) to the upper layer.

Description

Wireless link control device and method in mobile communication system {APPARATUS AND METHOD FOR DETERMINING PAGING ALERT MODE IN A MOBILE COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for transmitting a protocol data unit in a mobile communication system, and more particularly, to an apparatus and method for controlling a radio link for combining and transmitting a protocol data unit.

Next-generation mobile communication systems, which are currently being standardized, are classified into European and North American methods. The European method is represented by Universal Mobile Telecommunication System (UMTS), and the North American method is represented by IS-2000.

This next generation mobile communication system is composed of various protocol layers. Among them, the Radio Link Control (RLC) layer, which forms part of the second layer of the next-generation mobile communication system, is connected between a user equipment (UE), that is, a user terminal and a UTRAN (UMTS Terrestrial Radio Access Network). This is a protocol to ensure reliable data transmission. That is, in case of transmission, the RLC layer receives a RLC Service Data Unit (RLC SDU) from an upper layer and generates a RLC PDU (RLC PDU) to generate a lower layer. To send. The RLC transmission mode for transmitting an RLC PDU in the RLC layer may be divided into two modes. The first mode is the Unacknowledged RLC Mode, and the second mode is the Acknowledgment RLC Mode. On the other hand, in the case of reception, the reverse operation of the operation performed in the case of the above-described transmission is performed. That is, the RLC PDU is received from the lower layer to generate an RLC SDU and provided to the upper layer.

In this case, the RLC PDU may be classified into an Unacknowledged Mode Data Protocol Data Unit (UMD PDU) and an Acknowledgment Mode Data Protocol Data Unit (AMD PDU). The UMD PDU is a PDU which is transmitted to a counterpart when an abnormal reception is made by determining whether the received frame is normally received. The AMD PDU is a counterpart when the normal reception is performed by determining whether the received frame is normally received. It means the PDU to be transmitted to. The configuration of the UMD PDU and the AMD PDU is shown in FIGS. 1 and 2, respectively. The configuration shown in FIG. 1 and FIG. 2 is a frame format defined by the existing scheme (3GPP TS 25.322 version 1.2.1 or less).

First, referring to the components of the UMD PDU shown in FIG. 1, a sequence number (SN) is a field for recording an identification code for distinguishing a transmitted UMD PDU, and 7 bits are allocated. The length indicator (LI) is a field for recording a value indicating the end of the corresponding SDU constituting the data field, and 7 bits or 15 bits are allocated. 1 shows a 7-bit LI field, and the number of LI fields is determined corresponding to the number of RLC SDUs recorded in the data field. On the other hand, the PAD field is a field for recording additional padding bits to be added when the UMD PDU to be transmitted is not full. The data field is a field in which at least one RLC SDU provided from an upper layer is recorded. The Extension (E) bit field is a field for recording a bit indicating whether a data field follows the LI field or another LI field. An example of the E bit may be shown as a table and may be expressed as shown in Table 1 below.

E bit Contents 0 Next field indicates data One Indicates that the next field consists of the LI field and the E bit

As shown in Table 1, when "0" is recorded as an example of the E bit, it indicates that a data field starts next. When "1" is written, another RLC SDU is stored in the next field. Indicates that the LI field to start is started.

Next, referring to FIG. 2, the components of the UMD PDUs differentiated from those of the UMD PDUs described above will be described. In the case of the AMD PDUs, not only a function for distinguishing the transmitted AMD PDUs but also a Selective Repeat ARQ (Automatic Repeat) As the Request) function is performed, a sequence number (SN) is allocated to a 12-bit long field. The D / C field is used as a field for recording information for identifying whether a corresponding PDU is used as a control PDU or an AMD PDU. An example of the D / C field may be represented as a table as shown in Table 2 below.

D / C field bits Contents 0 Means that the PDU is used as the control PDU One Means the PDU is used as an AMD PDU

As shown in Table 2, when "0" is recorded as an example of the D / C field bit, it indicates that the corresponding PDU to be transmitted is the control PDU, and when "1" is recorded, Indicates that the PDU is an AMD PDU. Polling (P) is a field for recording a bit for determining whether or not to report status, an example thereof may be represented as shown in Table 3 below.

P bit Contents 0 - One Request Status Report (STATUS PDU)

As can be seen from Table 3, when a status report is required, "1" is written to the P bit. The Header Extension (HE) type bit records information to indicate that the next field is to be one of a data field, a LI field and an E bit, another HE field, a long LI field, and an E bit. Used as a field. An example thereof may be represented as shown in Table 4 below.

HE bit Contents 00 Next field indicates data 01 Indicates that the next field consists of the LI field and the E bit 10 Indicates that the next field is an Extended Header field 11 The next field indicates that it consists of a 15-bit long LI field and the E bit.

As shown in Table 4, when "00" is written as an example of the HE bit, the next field is a data field. When "01" is written, the next field is Indicates that the field consists of an LI field and an E bit. In addition, when "10" is recorded, the next field is an extended header field, and when "11" is recorded, a next field is a field consisting of a 15-bit long LI field and an E bit.

On the other hand, Fig. 3 is a diagram showing the range of SDUs designated by LI constituting the PDU as described above. Referring to FIG. 3 described above, the relationship between the SDU constituting the conventional PDU and the LI field is as described above. The information recorded in the LI field designates the end of any corresponding SDU among the SDUs constituting the data field. Done. Therefore, the specific range of the data field to which the corresponding SDU belongs can be determined by the information recorded in the LI field, and the range that can be determined by the information recorded in the LI field is determined by the information recorded in the LI field. It is limited by the limit bit number. This is because the end of the SDU is limited by the number of bits of the information recorded in the LI field. For example, when the limit bit of the information that can be recorded in the LI field is 7 bits, the limit for specifying the end of the SDU is "125". The reason is that the number of cases that can be indicated by the 7 bits is "128" or the use of the information recorded in the LI field is reserved for use other than the purpose of specifying the end of the SDU in three cases. Because it is. Therefore, in this case, when the size of the RLC PDU from the upper layer is 125 bytes or more or the beginning and end of the SDUs constituting the data field is 125 bytes or more, there is a problem that the above-described LI field cannot be displayed. In order to overcome this problem, a method of extending the LI field to 15 bits has been conventionally proposed, and this suggestion extends the range that can be indicated by the information recorded in the LI field.

4 illustrates an example in which at least two SDUs constituting a conventional RLC PDU are connected. As shown in FIG. 4, in the method in which the RLC SDU is recorded in the data field, an RLC SDU to be recorded is recorded by allocating a predetermined area of the data field, and then information indicating the end of the recorded RLC PDU is assigned to the corresponding LI field. It is in the form of writing on. Accordingly, it can be seen that the number of LI fields is determined by the number of SDUs constituting the data field. For example, when the number of SDUs constituting the data field is k, the number of corresponding LI fields is also provided. Should be.

However, in the case of the conventional method as described above, the following problems may be caused when referring to FIG. 4.

In a result of the RLC SUD, which is one of the functions provided by the above-described RLC layer, two or more RLC SDUs may occupy an area of 125 bytes or more in the data field of the RLC PDU. An example is the case where the 125th byte exists between a and b shown in FIG. When this happens, conventional methods cannot handle all RLC SDUs in one frame, so padding the rest (including SDU K-1 if the sequence numbers are consecutive) and then the next RLC PDU. You must recombine the remaining SDUs (more than SDU K, including SDU K-1). That is, in the case of LI (K) to indicate the SDU K (including the SDU K-1 when the sequence number is continuous) in FIG. 4 can not be used to transmit the SDU K according to the current RLC standard. The reason is that the current LI field is 7 or 15 bits followed by 1 bit of E bit, so the next LI field is 7 bits. However, since the long LI has already been used earlier to indicate the SDU K-1, the short LI that can be followed subsequently cannot represent the SDU K.

In addition, since the E field and the HE field, which are fields that perform similar functions, are used in duplicate, a problem arises in the implementation of the receiving RLC layer as well as the transmitting RLC layer.

Accordingly, an object of the present invention for solving the above problems is to provide a radio link control apparatus and method for efficiently combining and transmitting a plurality of service data units.

Another object of the present invention is to provide an apparatus and method for controlling a radio link for changing a header structure of a protocol data unit to efficiently combine and transmit a plurality of service data units.

Another object of the present invention is to provide a radio link control apparatus and method for changing a header structure of a protocol data unit to efficiently receive and process frames in which a plurality of service data units are combined.

A first aspect of the present invention for achieving the above object is to compare an apparatus for transmitting a protocol data unit in a mobile communication system with a maximum size of a protocol data unit capable of transmitting a service data unit from a higher layer. And a radio link control layer transmitter for combining the at least two service data units received from the upper layer to generate a protocol data unit and transmitting the combined data to the lower layer according to a set radio link control transmission mode when combining is required. When the protocol data unit from the layer is analyzed and the service data unit separation is required, it is implemented to include a radio link control layer receiver for separating and transmitting at least two service data units constituting the protocol data unit to the upper layer.

The second aspect of the present invention for achieving the above object is to combine the method of transmitting a protocol data unit in a mobile communication system by comparing the service data unit from a higher layer with the maximum size of the protocol data unit that can be transmitted. Generating a protocol data unit by combining at least two service data units received from the upper layer, if necessary, and transmitting the protocol data unit to the lower layer by using a set radio link control transmission mode; and transmitting the protocol data unit from the lower layer. When the service data unit separation is required to be analyzed and implemented, the method includes separating and transmitting at least two service data units constituting the protocol data unit to the upper layer.

1 is a diagram showing the configuration of a conventional unapproved protocol data unit.

2 is a diagram showing the configuration of a conventional grant protocol data unit.

3 is a diagram showing a range of service data units specified by a length identifier constituting a conventional protocol data unit.

4 is a diagram showing an example of connection of a service data unit constituting a conventional radio link control protocol data unit.

5 is a view showing the configuration of a radio link control apparatus according to an embodiment of the present invention.

6 is a diagram illustrating a configuration of an unapproved protocol data unit according to an embodiment of the present invention.

7 is a diagram illustrating a configuration of an admission protocol data unit according to an embodiment of the present invention.

8A is a diagram illustrating an example of a length identifier field configuration configuring a protocol data unit according to an embodiment of the present invention.

8B is a diagram illustrating another example of the configuration of a length identifier field constituting a protocol data unit according to an embodiment of the present invention.

9 is a diagram illustrating a control flow for transmitting a protocol data unit in a radio link control apparatus according to an embodiment of the present invention.

10 is a diagram illustrating a control flow for receiving a protocol data unit in a radio link control apparatus according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating a connection example of a service data unit constituting a radio link control protocol data unit according to an embodiment of the present invention. FIG.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description of the reference numerals to the components of the drawings, it should be noted that the same reference numerals as much as possible even if displayed on different drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. The terms to be described below are terms defined in consideration of functions in the present invention, and may be changed according to the intention or custom of the user or chip designer, and the definitions should be made based on the contents throughout the present specification. Meanwhile, in implementing the present invention, since the RLC layer is an essential configuration, it should be noted that detailed descriptions of the upper layer and the lower layer, which are other protocol layers, are omitted.

First, an RLC layer provided in a transmitter and a receiver required for implementing the present invention may be represented as a functional block as shown in FIG. 5. The RLC sublayer illustrated as a functional block in FIG. 5 is responsible for reliable data transmission between the UE and the UTRAN. On the other hand, the RLC layer performing the above functions is largely provided in the transmitting apparatus to convert the SDU from the upper layer into a PDU to provide to the lower layer, and the transmission RLC layer 510 provided in the receiving apparatus and PDU from the lower layer It may be divided into a receiving RLC layer 520 which is converted into an SDU and provided to a higher layer.

First, referring to the functional block of the transmitting RLC layer 510, the SDU receiving unit 512 receives an SDU from a higher layer and distributes the same to the processing functional block. That is, the distribution of the SDU provided from the upper layer is determined by comparing the size of the SDU with the maximum size of the RLC PDU that can be transmitted in the lower layer. In more detail, when the size of the SDU is larger than the maximum size of the transmittable RLC PDU, the SDU is provided as a functional block for dividing the SDU. Otherwise, when the size of the SDU is smaller than the maximum size of the transmittable RLC PDU, the SDU is provided as a functional block for combining with at least one SDU provided before or next. On the other hand, when the size of the SDU is the same as or similar to the maximum size of the transmittable RLC PDU is provided as a functional block for processing the SDU into a PDU frame. In fact, it may be desirable to consider that the maximum size of the transmittable RLC PDU, which is a reference for comparison with the SDU, is substantially the size of an area where data can be transmitted. The SDU segmentation unit 513 divides the SDU provided from the SDU receiver 512 into the maximum size of the transmittable RLC PDU, and the SDU concatenation 514 separates the SDU from the SDU receiver 512. Combine at least two SDUs provided to the maximum size of the transmittable RLC PDU. The framing unit 515 performs a framing process of processing an RLC PDU in a form that can be transmitted using an SDU provided from the SDU receiver 512, the SDU divider 513, or the SDU combiner 514. The frame process performed by the frame unit 515 will be described later. The transmission buffer 516 temporarily stores the RLC PDU frame from the framer 515 and transmits the RLC PDU frame to the lower layer according to the corresponding RLC transmission mode. In this case, as described above, the RLC transmission mode collectively refers to an acknowledgment RLC mode and an unacknowledged RLC mode.

Next, referring to the functional block of the RLC layer 520, the reception buffer 526 temporarily stores an RLC PDU frame provided through a lower layer. The inverse framing unit 525 accesses the RLC PDU frame stored in the reception buffer 526 and performs inverse framing in contradiction with the framing process performed by the framing unit 515 of the transmitting RLC layer 510. On the other hand, the inverse framer 525 determines the framing process by the SDU obtained through inverse framing. That is, the RLC PDU determines whether a predetermined SDU is divided or combined by the framing process or includes only one SDU.

The SDU re-assembly unit 523 assembles and outputs at least two SDUs provided from the inverse frame unit 525 into one SDU. The assembling of the SDUs consists of SDUs divided by the SDU divider 513 constituting the transmitting RLC layer 510 as a complete SDU. Header information must be provided. The PDU frame may be divided into at least one SDU constituting a data area and a header for carrying various data required for transmitting the frame. Predetermined header information required for the SDU assembly among the headers of the PDU frame means information proving that the information is divided from the same SDU among the information contained in the header constituting the frame, and specific embodiments thereof will be described in detail below. Do it. The SDU separator 524 separates and outputs each SDU from an SDU bundle in which at least two SDUs provided from the inverse framer 525 are bundled. In order to separate each SDU from the SDU bundle, separate predetermined header information is required, which must also be provided from the deframer 525. The SDU transmitter 522 transmits the SDUs from the inverse frame unit 525, the SDU assembly unit 523, or the SDU separator 524 to a higher layer.

FIG. 6 is a diagram illustrating a format of an unapproved RLC PDU frame among RLC PDU frames provided between the transmitting RLC layer 510 and the receiving RLC layer 520 described above with reference to FIG. 5, and FIG. 7 is a grant RLC PDU frame. It is a figure which shows the format of.

Referring to the header structure of the disapproved RLC PDU frame structure according to an embodiment of the present invention with reference to FIG. 6, a sequence number (SN) allocated to 8 bits is conventionally allocated to 6 bits in the present invention. The length identifier (LI), which has been assigned to bits or 15 bits, is assigned to 6 bits or 14 bits in the present invention (FIG. 6 discloses only 6 bits). In addition, an extension bit (E), which has been conventionally assigned to 1 bit, is replaced with a header extension (HE) bit, and the HE bit is allocated to 2 bits.

The reason why it is irrelevant even if the SN field of the unapproved RLC PDU frame is allocated to 6 bits according to an embodiment of the present invention is as follows. Typically used in non-approved mode RLC, SN is used to guarantee in-sequence delivery of PDUs and to find and discard duplicated PDUs. It is not used for Therefore, although the size of the SN is defined as 7 bits in the conventional non-approved mode RLC, the non-approved mode RLC without any error control function does not require many sequence numbers. In addition, the possibility of SN inversion in the disapproved mode RLC is most likely to occur during the macro-diversity process performed during the multi-path phenomenon or the soft hand-off process. The rest of the cases are rare. In addition, even in the macro-diversity process, the actual distance difference is mostly due to the distance difference between the user terminal and the different base station Node B, and thus the base station Node B is farthest from the user terminal. Assuming a distance of 10 km, the propagation delay is 0.033 [msec]. In this case, even if the capacity of the channel is 2 Mbps, which is the ultimate target in the next generation mobile communication system, the length of data on the transmission path is 9 bytes or less according to calculation. Therefore, even if the sequence number is assigned to 6 bits in the non-approved mode RLC according to an embodiment of the present invention, a maximum number of 127 PDUs (or PU: Payload Units) can be distinguished from each other. will be.

Referring to the header structure of the approved RLC PDU frame structure according to an embodiment of the present invention with reference to FIG. 7, the sequence number (SN; Sequence Number) is assigned to 12 bits in the present invention as in the prior art, the conventional 7-bit or The length identifier (LI), which was allocated 15 bits, is allocated to 6 bits or 14 bits in the present invention. In addition, an extension bit (E), which has been conventionally assigned to 1 bit, is replaced with a header extension (HE) bit, and the HE bit is allocated to 2 bits.

In order to solve the problems of the conventional method as can be seen in the configuration of the PDU described above with reference to FIGS. 6 and 7, the present invention proposes a new format of RLC PDU (UMD PDU and AMD PDU). . In the above-described PDU format, the length of the Long LI field is reduced to 14 bits, and the length of the Short LI field is also adjusted to 6 bits. In addition, in the conventional configuration in which the E / HE bits coexisted, the E bits are no longer used by uniformly allocating the HE bits. In particular, in the case of the UMD PDU, the sequence number is adjusted to 6 bits in order to use the HE bit instead of the conventional E bit. In this case, it is possible to solve the resource waste problem that may occur in the conventional SDU concatenation process.

Meanwhile, an example of functions determined by HE bits that are uniformly allocated in FIGS. 6 and 7 may be represented as shown in Table 5 below.

HE bit Contents 00 Next field indicates data 01 Indicates that the next field consists of a 6-bit short LI field and the HE bit. 10 Indicates that the next field is an Extended Header field 11 Indicates that the next field consists of a 14-bit long LI field and the HE bit.

As shown in Table 5, when "00" is written as an example of the HE bit, the next field is a data field. When "01" is written, the next field is Indicates that the field consists of a 6-bit short LI field and a HE bit. If "10" is written, the next field is an extended header field. If "11" is written, the next field is a 14-bit long LI field and a HE bit. Indicates that In other words, it can be seen that the bits of the HE field defined by the embodiment of the present invention are allocated different functions from the bits of the HE field which have been previously defined. That is, in contrast to the above-described Tables 4 and 5, the same functions are assigned in the case of "00" and "10", but different functions are assigned in the case of "01" and "11". This is because the present invention changes the E field to the HE field and adjusts the number of bits of the LI field.

In addition, as described above, the length identifier LI constituting the PDU according to the present invention may be composed of 6 bits or 14 bits. 8A and 8B show respective LI field structures therefor. In FIG. 8A, 6 bits of the 1-byte area are allocated to the LI field, and the remaining 2 bits are allocated to the HE field. In FIG. 8B, 14 bits of the 2-byte area are allocated to the LI field, and the remaining 2 bits. Is assigned to the HE bit.

9 is a diagram illustrating a control flow for converting an SDU from an upper layer into a PDU corresponding to a corresponding RLC transmission mode and providing the lower layer in a transmitting RLC layer according to an embodiment of the present invention. However, in FIG. 9, the concept of loading a plurality of Payload Units (PUs) in one AMD PDU is not included in the disclosure of the present invention. The reason for this is that when the above-mentioned part is included and disclosed, it becomes too complicated. If only a part of FIG. 9 is modified, there is no big problem in introducing the concept of carrying a plurality of PUs.

Referring to FIG. 9, when receiving an RLC SDU from an upper layer, comparing the maximum size of a transmittable RLC PDU with the received SDU size, etc., combining at least two SDUs received when a concatenation process is required. RLC PDUs are generated, and the generated RLC PDUs are temporarily stored in a transmission buffer and then the temporarily stored RLC PDUs are transmitted to a receiving RLC layer according to an RLC transmission mode (Unacknowledged or Acknowledged RLC Mode).

A connection example of the SDUs constituting the RLC PDU finally transmitted by the control flow shown in FIG. 9 is as shown in FIG. 11.

FIG. 10 is a diagram illustrating a control flow for converting a PDU from a lower layer into an SDU and providing it to an upper layer in a receiving RLC layer according to an embodiment of the present invention.

Referring to FIG. 10, when an RLC PDU is received from a lower layer, when a separation process is requested, a process of transmitting to at least two RLC SDUs recorded in a data field of the RLC PDU frame is performed.

In the present invention, by changing the RLC PDU format of the conventional scheme, LI is changed into two types of 6 bits and 14 bits (Fig. 6 (4), Fig. 7 (7) and Fig. 8) and the rest of the 2-bit HE. It is used as a field (Fig. 6 (6), Fig. 7 (8) and Fig. 8). In the case of the UMD PDU, the Sequence Number is also changed to 6 bits (Fig. 6 (3)), and then the HE Bit was used (Fig. 6 (5)). Therefore, the meaning of the value of the HE bit is also changed as shown in Table 1 ((9) and (10) in Table 1). 8 shows the structure of a Short / Long LI (6 bit / 14 bit) field. In this way, due to the problem of the LI field in the conventional method, if the end of the SDU is 125 bytes or more in the RLC PDU (more than SDU K in FIG. 10 and SDU K-1 if the sequence numbers are consecutive), cancatenate cannot be performed. It is possible to solve the resource waste caused by transmitting the data through the next RLC PDU. In addition, in the existing scheme, the overlapping use of the similar HE and E bits is unified with one HE bit to solve the inconvenience of implementing the protocol.

Hereinafter, an operation according to an embodiment of the present invention will be described in detail with reference to the above configuration. First, an operation according to an embodiment of the present invention may be largely divided into a transmission operation and a reception operation. In the following description, the operation according to an embodiment of the present invention will be described. In addition, when defining the identifiers to be used in describing the operation of the present invention, "Is" represents information specifying the end of the last RLC SDU of the RLC SDU constituting the RLC PDU frame, "T" is short (Short) Indicates the maximum value that can be specified as information that can be recorded in the LI field. "Es" represents a state in which there is no SDU to transmit in the transmission buffer, and "Ep" represents a state in which no more PDU space is needed. Meanwhile, as described above, in describing the operation according to the exemplary embodiment of the present invention, detailed descriptions of operations determined to be unnecessary in the present invention and operations already known as the prior art will be omitted.

First, a transmission operation according to an embodiment of the present invention will be described in detail with reference to the configuration of the transmission RLC layer 510 shown in FIG. 5 and the control flow shown in FIG. 9.

When the SDU receiving unit 512 receives the RLC SDU from the upper layer in step 910 of FIG. 9, the SDU receiving unit 512 proceeds to step 912 to determine whether the size of the provided SDU is necessary for combining. The determination can be made by comparing the size of the data field constituting the transmittable RLC SDU and the transmittable RLC PDU. That is, based on the comparison result, it is determined whether to perform segmentation, concatenation, etc. of the provided SDUs, or determine whether to perform the framing process immediately.

If the determination result combining step is not required in step 912, the transmitting RLC layer 510 performs a normal division process or a frame process through the provided RLC SDU according to the determination result. Since the division process is irrelevant to the technical spirit to be implemented in the present invention, a detailed description thereof will be omitted.

However, if it is determined in step 912 that the SDU combining process is required, it means that at least two SDUs can be transmitted through one RLC PDU. In step 914, the SDU combining unit 514 indicates that T is Is. Compare greater than Comparing whether T is greater than Is is to determine whether the end of the last RLC SDU can be specified among the RLC SDUs constituting the RLC PDU frame as information that can be recorded in the Short LI field. In this case, as described above, at least two SDUs are combined to form one RLC PDU. As described above, at least two SDUs are combined using the LI field. . If it is determined in step 914 that T is greater than Is, the maximum value that can be recorded in the short LI field in configuring the RLC PDU is 14 bit because the end of the last RLC SDU cannot be specified. Long LI bits should be used. On the contrary, if it is determined in step 914 that T is not greater than Is, 6 bits may be designated as the end value of the final RLC SDU as the maximum value that can be recorded in the short LI field in configuring the RLC PDU. The short LI bit of must be used.

First, a detailed operation performed when it is determined in step 914 that T is greater than Is (short LI is required) will be described.

The SDU combiner 514 proceeds to step 916 to record the sequence number of the first SDU (or PU) in the SN field included in the header constituting the RLC PDU. Here, the first SDU (or PU) means the first SDU (or PU) recorded in the data field constituting the RLC PDU. In addition, since LI is required to indicate the end of the first SDU (or PU) recorded in the data field of the RLC PDU, in step 916, whether the short LI field is used as the LI field in the header of the RLC PDU is long. You must decide whether to use the field. Information for determining this is recorded in the HE field in the header of the RLC PDU. Since the determination of the LI field to be used has already been determined to use the short LI field in step 914 described above, in step 916, the LI field to be used is designated as a short LI field by recording " 01 " do. To indicate that the short LI field is "01" is already disclosed as an example through Table 5. Since information that can be recorded in the short LI field is limited to 6 bits, information indicating the end of the SDU (or PU) may represent up to 63 bytes. However, the last two values of the 63 bytes (eg, "111110" and "111111") may be substantially written in the short LI field as they are already used for other purposes than information indicating the end of the SDU (or PU). The maximum number of bytes is 61 bytes.

When the SN and the HE are determined in step 916, the SDU combiner 514 proceeds to step 918. The SDU combiner 514 proceeds to step 918 and stores information indicating the end of the SUD corresponding to the determined short LI field. Information for designating the end of the SDU means information for designating an end position of a predetermined data field area of the RLC PDU in which the SDU is recorded.

At this time, the above-described step 918 is repeatedly performed until there are no more SDUs to be transmitted in the transmission buffer 516 or storage of an SDU (or PU) is no longer possible in the data field constituting the RLC PDU. This is determined in step 920. The method of determining is determined by a logical OR condition in which there is no SDU to be transmitted to the transmission buffer (Es) and a state (Ep) in which no more PDU space is needed. do. If either of the two conditions is satisfied by the determination, the process proceeds to step 924. Otherwise, if the two conditions are not satisfied, the process proceeds to step 922.

In this case, proceeding to step 922 indicates that there is a subsequent SDU that can be recorded in the data field of the RLC PDU. Accordingly, the SDU combiner 514 proceeds to step 922 and records information indicating that a short LI field is to be used in the HE field of the RLC PDU header corresponding to the subsequent SDU, and then " 01 " Will proceed. In step 918, as described above, the operation indicating the end of the subsequent SDU is recorded in the short LI field designated in step 922, and the subsequent SDU is recorded in the predetermined data field area of the RLC PDU.

On the contrary, the operation 924 means that there is no region to record the subsequent SDU in the data field of the RLC PDU by repeating the operation 918 even if the subsequent SDU does not exist or the subsequent SDU exists. will be. Accordingly, the SDU combiner 514 proceeds to step 924 and sets the predetermined information "00" in the predetermined HE field to indicate that the LI field no longer exists and the data field starts. On the other hand, in step 924, if there is space left in the data field of the RLC PDU, a piggybacked state PDU or padding process is performed in place of the SDU in the remaining space. The above processing is for completing the RLC PDU to be transmitted to the size of the RLC PDU determined in the call setup process. Meanwhile, when the RLC PDU of the size determined in the call setup process is completed, the SDU combiner 514 records the last address "111111" or "111110" which can be designated in the short LI field.

Secondly, a detailed operation performed when it is determined in step 914 that T is not greater than Is (when a long LI is required) will be described.

In step 926, the SDU combiner 514 records the sequence number of the first SDU (or PU) recorded in the data field constituting the RLC PDU in the SN field included in the header constituting the RLC PDU. In addition, since it is determined that the long LI field is to be used as the LI field for indicating the end of the first SDU (or PU) recorded in the data field of the RLC PDU, the " 11 " ". Indication of the long LI field as “11” is already disclosed as an example through Table 5.

If the SN and the HE is determined in step 926, the SDU combiner 514 proceeds to step 928. The SDU combiner 514 proceeds to step 928 and stores information indicating the end of the SUD corresponding to the determined long LI field. Information for designating the end of the SDU means information for designating an end position of a predetermined data field area of the RLC PDU in which the SDU is recorded.

In this case, step 928 described above is repeatedly performed until there are no more SDUs to be transmitted to the transmission buffer 516 or storage of the SDUs (or PUs) is no longer possible in the data field constituting the RLC PDU. This is determined in step 930. The method of determining is determined by a logical OR condition in which there is no SDU to be transmitted to the transmission buffer (Es) and a state in which no more PDU space is needed (Ep). do. If either of the two conditions is satisfied, the process proceeds to step 934; otherwise, the process proceeds to step 932 if both conditions are not satisfied.

In this case, proceeding to step 932 means that there is a subsequent SDU that can be recorded in the data field of the RLC PDU. Accordingly, the SDU combiner 514 proceeds to step 932 and records information indicating that the long LI field is to be used in the HE field of the RLC PDU header corresponding to the subsequent SDU, and then, in step 928. Will proceed. In step 928, as described above, the information indicating the end of the subsequent SDU is recorded in the long LI field designated in step 932, and the subsequent SDU is recorded in the predetermined data field area of the RLC PDU.

In contrast, proceeding to step 934 means that there is no region for recording the subsequent SDU in the data field of the RLC PDU by repeating the operation 928 even if the subsequent SDU does not exist or the subsequent SDU exists. will be. Accordingly, the SDU combiner 514 proceeds to step 934 and sets the predetermined information "00" in the predetermined HE field to indicate that the LI field no longer exists and the data field starts. On the other hand, in step 934, if there is remaining space in the data field of the RLC PDU, a piggybacked state PDU or padding process is performed in place of the SDU in the remaining space. The above processing is for completing the RLC PDU to be transmitted to the size of the RLC PDU determined in the call setup process.

When the values of the respective fields constituting the RLC PDU frame are determined in step 924 or 934, the framer 515 performs a framing operation for configuring the RLC PDU frame based on the field values determined in step 936. The framing operation consists of writing the determined field values in a corresponding frame area. When generation of the RLC PDU frame is completed by the above-described operation, the framer 515 outputs to the transmission buffer 516 in step 938 and is transmitted to the reception RLC layer 520 through the lower layer.

Next, a reception operation according to an embodiment of the present invention will be described in detail with reference to the configuration of the reception RLC layer 520 disclosed in FIG. 5 and the control flow shown in FIG. 10.

As described above, the RLC PDU transmitted from the transmitting side is stored in the receiving buffer 526 provided at the receiving side. The inverse framing unit 525 reads the PLD PDU stored in the reception buffer 526 in step 1012 of FIG. 10 to perform inverse framing by the inverse operation of the operation for framing in the framing unit 515 of the transmitting side. do. On the other hand, the deframer 525 determines whether SDUs constituting the PLD PDU are required to be decoupled by the frames processed by the deframe in step 1014. The need for the reverse combining indicates that the combining process of the plurality of SDUs has been performed by the SDU combining unit 514 at the transmitting side.

If the decoupling is not required by the determination, the deframer 525 provides the SDU assembly unit 523 or the SDU transmitter 522 according to the state of the frames in which the deframer is performed in step 1016. However, if the reverse coupling is required by the determination, the deframer 525 proceeds to step 1018 to provide the frames to the SDU reverse combiner 524. The SDU decoupling unit 524 receiving the frames analyzes the information recorded in the HE region constituting the provided PDU frame in step 1018. When the analysis of the information recorded in the HE region is completed, the SDU reverse coupling unit 524 proceeds to step 1020 to determine whether the analyzed HE indicates 01. The fact that the HE has information of 01 means that a plurality of short LIs are used in combining SDUs at the transmitting side.

If it is determined in step 1020 that the HE has information of 01, the SDU decoupling unit 524 proceeds to step 1022. However, if it is determined in step 1020 that the HE does not have the information of 01, the SDU decoupling unit 524 means that the long LI is used at the transmitting side. Proceeds to step 1024.

If the SDU decoupling unit 524 proceeds to step 1022, the SDU decoupling unit 524 analyzes each of the plurality of SDUs constituting the PDU frame based on a plurality of pieces of short LI information constituting the PDU frame. In contrast, when the SDU decoupling unit 524 proceeds to step 1024, the SDU decoupling unit 524 analyzes each of the plurality of SDUs constituting the PDU frame based on a plurality of long LI information constituting the PDU frame.

The SDU reverse combiner 524 proceeds to step 1026 when the analysis of the SFDU constituting the PDU frame is completed in steps 1022 and 1024. In step 1026, the SDU reverse combiner 524 provides the analyzed SDUs to the SDU transmitter 522 so that the SDU transmitter 522 can provide the SDUs to a higher layer.

As described above, FIG. 10 describes a frame receiving process according to an embodiment of the present invention in more detail. However, in FIG. 10, the description of the present invention does not include the header compression used in the AMD RLC and the concepts of loading a plurality of Payload Units (PUs) in one PDU. The reason is that it is too complicated to include even this part, and if only a part of the modification in Figure 10 is introduced, there is no big problem in introducing this concept.

As described above, the transmitting side combines a plurality of SDUs to complete an RLC PDU, and the completed RLC PDU is transmitted to the counterpart RLC through a lower layer. Meanwhile, the other RLC recovers the RLC SDU from the received RLC PDU through an inverse process of the process performed by the transmitting side. When the recovered RLC SDU is transmitted to a higher layer, data transmission through the RLC layer is completed. On the other hand, when performing the concatenation process, the classification of each SDU is solved using the LI field. In this way, the RLC on the receiving side recovers the original RLC SDUs by the reverse process and delivers them to the upper layer.

Effects obtained in the present invention as described above are as follows.

First, in the present invention described above, the LI notation constraints that may occur by concatenation of multiple SDUs by changing the LI field of the RLC PDU format to 6 bits and 14 bits, and the Sequence Number field to 6 bits in the case of an unapproved mode PDU. Overcome it.

Secondly, the present invention described above solves the problem of resource waste caused by a process of padding the remaining part and transmitting the next RLC PDU when the SDU size becomes more than 125 bytes by concatenation in the conventional method.

Third, in the present invention described above, the problem of complexity of the protocol is overcome by unifying the HE field and the HE field having similar functions together in the HE field.

Fourth, although the current specification partially solves the segmentation and concatenation problems that may occur in the non-approved mode RLC and the approved mode RLC only in the approved mode RLC, the present invention described above may cause problems in the non-approved mode PDU, that is, Even in the case of unauthorized PDUs, despite the fact that the RLC PDU size can be more than 125 bytes, the problem of not being able to use Long LI has been solved to eliminate the unbalance problem between the current RLC modes.

Claims (6)

An apparatus for transmitting a protocol data unit in a mobile communication system, Radio link control set after generating a protocol data unit by combining at least two service data units received from the upper layer when combining is required by comparing the service data unit from the upper layer with the maximum size of the transmittable protocol data unit. A radio link control layer transmitter for transmitting to a lower layer in a transmission mode, And a radio link control layer receiver for analyzing protocol data units from the lower layer and separating at least two service data units constituting the protocol data unit and transmitting them to the upper layer when service data unit separation is required. Radio link control device in a mobile communication system characterized in. The method of claim 1, wherein the radio link control layer transmitter, And a transmission buffer for temporarily storing the generated protocol data unit before transmitting it to the lower layer. The method of claim 1, wherein the radio link control layer receiving unit, And a receiving buffer for temporarily storing the protocol data unit from the lower layer. In the method for transmitting a protocol data unit in a mobile communication system, Radio link control set after generating a protocol data unit by combining at least two service data units received from the upper layer when combining is required by comparing the service data unit from the upper layer with the maximum size of the transmittable protocol data unit. Transmitting to a lower layer by a transmission mode, And analyzing at least two service data units constituting the protocol data unit by analyzing protocol data units from the lower layer and transmitting the service data units to the upper layer when separation of service data units is required. A method of controlling a radio link in a communication system. The method of claim 4, wherein And storing the generated protocol data unit temporarily before transmitting the generated protocol data unit to the lower layer. The method of claim 4, wherein And temporarily storing a protocol data unit from the lower layer.