KR100365356B1 - Acknowledged mode entity in radio link control - Google Patents

Abstract

The present invention relates to a recognition mode (AM mode) entity structure of a 3GPP RLC layer.

According to the present invention, when performing data transmission / reception processing in the radio link control (RLC) AM mode, the transmitting end (a). Configuring the SDUs from the higher into PDUs and adding headers to store the AMD PDUs in the transmit buffer, (b). Setting a predetermined field of a PDU header stored in the transmission buffer, encrypting and transmitting the predetermined field, and receiving (c) decrypting the encrypted AMD PDU transmitted from the transmitting end of the communication counterpart and storing it in the receiving buffer. , (d). Removing headers and piggyback information from the AMD PDUs stored in the reception buffer, extracting only data, configuring SDUs, and then reassembling and transmitting the data to the upper level; A data transmission / reception processing method in a recognition mode (AM) of a radio link control (RLC), which is characterized in that the processing is performed in the transmission buffer, the field setting block, and the reception buffer. PDU processing time in the RLC layer can be shortened.

Description

ACKNOWLEDGED MODE ENTITY IN RADIO LINK CONTROL}

The present invention relates to the recognition mode (AM mode) entity structure of the 3GPP RLC layer, and in particular, solves the problem of ciphering / deciphering that may occur when using the conventional RLC AM entity structure. The present invention relates to an improved method for transmitting and receiving RLC AM data.

In particular, in the RLC AM entity structure, the transmitting end has an encryption step in the final processing step after the field setting block via the transmission buffer, and the receiving end has a decryption step in the first processing step before the receiving buffer. We propose an RLC AM entity structure that enables more efficient transmission and reception of PDUs.

More specifically, in the RLC AM entity structure, the transmitting end stores the SDUs descending from the upper into a PDU having a constant size, attaches the headers to the transmission buffer, and stores the other fields except for the sequence number of the RLC header. After setting to, it encrypts and transmits, and the receiving end receives the PDU, decrypts it, stores it in the receiving buffer, removes the header, reassembles it, and sends it to the upper layer, thereby shortening the processing time of the PDU in the RLC layer. We propose an RLC AM entity structure.

In light of the fact that there are many researches on communication technologies that allow time-space-free and unlimited access to multimedia, and many efforts for the visible results of the research, the development of digital data processing and transmission technology integrates wired and wireless communication. The implementation of a real-time global data communication system using satellites is on the horizon.

Also, thanks to the development of digital data processing and transmission technology, it is possible to freely access information anytime, anywhere, regardless of existing voice calls, real-time transmission of network-based still images, moving images and wired or wireless.

IMT-2000 will be one of them. First-generation mobile communication refers to analog, second-generation mobile communication refers to the evolution of digital, and third-generation mobile communication is commonly called IMT-2000. For international standardization of the IMT-2000, in December 1998, a third group of national or national standards-setting bodies, such as ETSI in Europe, ARIB / TTC in Japan, T1 in the United States and TTA in Korea, The 3rd Generation Partnership Project (hereinafter referred to as 3GPP) is a combination of 3GPP and the detailed specification of the European IMT-2000 system applying WCDMA wireless access technology. The Radio Link Control (RLC) layer referred to in the present invention is a second layer of the IMT-2000 communication system proposed by 3GPP, and provides a data link. This protocol layer corresponds to the second layer of the OSI 7-layer model, and the type of RLC entities used in the IMT-2000 communication system currently proposed by 3GPP is Tr mode (transparent) without an RLC header. Mode and NTr mode with headers (Non-transparent Mode).

NTr mode is divided into UM mode (Unacknowledged Mode) (UM) without acknowledgment (ACK) signal from the receiver, and AM mode (Acknowledged Mode) with acknowledgment (ACK) signal. Accordingly, three types of RLC modes currently used are Tr, UM, and AM. Among them, the structure of an AM entity is shown in FIG. 1.

Referring to FIG. 1, in the AM entity (Transmitting Side) of the transmitting end, segmentation (SDU) is used to make Service Data Units (SDUs) descending from a higher level into Protocol Data Units (PDUs). segmentation or concatenation (step 101), to which a header containing a sequence number (SN) is attached (step 102).

The PDUs with the headers are sent down and at the same time stored in a retransmission buffer 103 for retransmissions that may occur in the future. The PDU descended down through the multiplexer 104 is stored in the transmission buffer 106 once through a process of ciphering (step 105) to secure the data and then set fields block. The set field block 107 sets the other fields (D / C, Poll field, etc.) except the sequence number (SN) of the RLC header to an appropriate value. ) Will be sent.

The PDU carrying data information obtained from the upper layer is called an AMD (AM Data) PDU, and its structure is shown in FIG.

That is, the Radio Link Control (RLC) layer receives a protocol data unit (PDU) at the receiving end and then receives an unacknowldeged PDU (UMD PDU) and an acknowledgment signal when the acknowledgment signal (ACK) to the transmitting side is not necessary. There are two types of PDUs, AMD PDUs (Acknowldeged PDUs), which are used when the PDU is required. The format of the AMD PDU is a header, a LI part (Length Indicator group) and data (Data) as shown in FIG. It consists of a state PDU of type PAD (padding) or piggyback type.

The header includes a sequence number, which is a field indicating the sequence number of each PDU, a 1-bit D / C field indicating whether the corresponding PDU carries data information or control information, and a status report to the receiver. A 1-bit polling field (P field) requesting a status report, a 2-bit HE (Header Extension) field indicating whether the next data is data, or LI and E bits, followed by a field It includes 1 bit of the E (Extension) field to indicate whether the data is the data or the LI and the E bits.

In the AMD PDU, the LI portion is composed of LI and E bits. LI is a field indicating the boundary of each SDU when the PDU includes several SDUs. Each LI represents the octet number from the first octet of the data portion to the end octet of each SDU. Each LI for each SDU included in one PDU is called an LI group.

The Data part is a field corresponding to the SDUs descended from the upper layer, and includes one or several SDUs. Since the data part is variable in size, padding is used to octet-align the entire PDU size. (padding)

The ciphering described above is done for AMD PDUs, where the first two octets, the header part, are not ciphered, only the part after it is ciphered. .

In addition to these AMD PDUs, there are also control PDUs containing control information in the AM entity. The types of control PDUs include status PDUs containing status information, and reset of AM entities. There are three Reset PDUs for Reset and Reset ACK PDUs for indicating Acknowledgment (ACK), which are shown in FIGS. 3 and 4, respectively.

These control PDUs are created in the RLC Control Unit and sent directly to the Set fields block without ciphering, where the D / C and PDU type fields are set and then received at the receiving end. Is sent to (Receiving Side)

That is, in the set fields block 107, the D / C field is set to 1 for the AMD PDU and 0 for the control PDU. If the data is not occupied in the AMD PDU and there is a vacancy, padding (PAD) is performed. In the set fields block 107, when the PAD is included in the AMD PDU, data transmission efficiency is increased. The status PDU may be filled and transmitted instead of the PAD. The status PDU at this time is called a piggybacked status PDU.

As described above, the receiving side receiving the PDU of the AM entity transmitted from the transmitting side processes the AMD PDU as follows.

First, the demultiplexing / routing unit (Demux / Routing) 108 checks the D / C field. As a result of checking the D / C field, if the value of the D / C field is 0, it is a control PDU. Therefore, the control PDU is sent directly to the RLC control unit 100. If the value of the D / C field is 1, the AMD PDU is an ADM PDU. Receiver buffer (109) is sent to.

The RLC AM entity can use one or two logical channels for one Radio Bearer setup, in which the solid line uses one logical channel and the dashed line two When two logical channels are used, the AMD PDU is transferred directly to the receiver buffer 109 because the data and control channels are defined, and the control PDU is demultiplexed / routed. / Routing) 108 is transmitted to the RLC control unit 100.

The receiver buffer 109 checks the reception status of each PDU, and when there is a PDU that has not been received, requests a retransmission for the PDU that has not received a NACK signal to the transmitter. The PDUs stored in the receiver buffer 109 are stored until all PDUs constituting one complete SDU are received, and then, when all the PDUs are received, they are uploaded in units of SDUs. After that, they are decoded in the deciphering step 110. After removing the RLC header and piggybacked information from each PDU and extracting only the data to configure the SDU (step 111), the reassembly process is performed. It is sent to the top via (112).

However, using the above-described prior art has the following problems in transmitting the AMD PDU.

First, in order to transmit a piggybacked status PDU (PDU) at the transmitting end, it is checked in the set fields block whether there is a PAD for the piggybacked status PDU in the AMD PDU, and the piggybacked status PDU is included in the AMD PDU. If you have a PAD that will contain a PAD, you should replace it with a piggybacked state PDU. Since the AMD PDU is already encrypted, set the field to see if there is a PAD and where the exact PAD is located. In the block), the encrypted AMD PDU must be decrypted again. In addition, since ciphering must be performed again for transmission, there is a disadvantage in that deciphering / ciphering is unnecessarily performed in a set field block.

In addition, when the receiver sends PDUs from the receiver buffer to the upper level, they are sent in units of SDUs. PDUs stored in the receiver buffer are already encrypted by the transmitter. Therefore, in order to know whether a PDU belongs to one SDU, it must be deciphered to determine whether it is a PDU belonging to one SDU, and therefore, a disadvantage of requiring deciphering function unnecessarily even in a receiver buffer. There is this.

This overlapping encryption and decryption is a cause of slowing down AMD PDU data processing speed and efficiency, and deteriorates system performance.

In addition, there is an SDU discard function that is used to prevent the overflow of the buffer, which is the function of the RLC. When this is used, all PDUs corresponding to the SDUs to be discarded in the send buffer and the receive buffer are discarded. Since both PDUs and receive buffers are stored with encrypted PDUs, there is a disadvantage in that a decryption function is required in both the transmit / receive buffers for SDU discarding.

According to the present invention, in the RLC AM entity structure, the transmitting end puts an encryption step in the final processing step after the field setting block, and the receiving end puts a decryption step in the first processing step before the receiving buffer, so that PDU transmission and reception can be performed more effectively. We propose an RLC AM entity structure-data transmission / reception method.

According to the present invention, in the RLC AM entity structure, the transmitting end stores the SDUs descending from the upper into a constant PDU, attaches the headers to the transmit buffer, and sets other fields except the sequence number of the RLC header to an appropriate value. RLC AM which encrypts and transmits, and receives and decrypts the PDUs, stores them in the receiving buffer, removes the headers, reassembles them, and sends them to the upper layer, thereby reducing the PDU processing time in the RLC layer. We propose an entity structure.

1 illustrates a conventional RLC AM entity structure.

2 is a diagram for explaining the structure of an AMD PDU;

3 is a diagram for explaining the structure of a status PDU;

4 is a diagram for explaining the structure of a reset and reset recognition PDU;

5 is a diagram illustrating an RLC AM entity structure proposed in the present invention.

The present invention performs data transmission / reception processing in the radio link control (RLC) AM mode, (a). Configuring the SDUs from the higher into PDUs and adding headers to store the AMD PDUs in the transmit buffer, (b). Setting a predetermined field of a PDU header stored in the transmission buffer and transmitting the encrypted field; And a data transmission processing method in a recognition mode AM of the radio link control RLC.

In the data transmission processing method in the recognition mode AM of the radio link control (RLC) of the present invention, the data transmission unit of the SDU is performed in the transmission buffer.

In the data transmission processing method of the radio link control (RLC) recognition mode of the present invention, the D / C field is checked before the encryption, and the control PDU encrypts and transmits only the AMD PDU without performing encryption. It is characterized by.

Also, in the data transmission processing method of the radio link control (RLC) recognition mode (AM) of the present invention, when the AMD PDU includes a piggybacked state PDU, the piggybacked state PDU performs encryption and the state PDU performs encryption. It is characterized in that the transmission without performing.

In addition, the present invention, when performing data transmission and reception processing in the radio link control (RLC) AM mode, (a). Decrypting the encrypted AMD PDU transmitted from the transmitting end and storing it in the receiving buffer, (b). Removing headers and piggyback information from the AMD PDUs stored in the reception buffer, extracting only data, configuring SDUs, and then reassembling and transmitting the data to the upper level; The data reception processing method in the recognition mode AM of the radio link control (RLC), characterized in that the processing.

In the data receiving processing method in the recognition mode AM of the radio link control (RLC) of the present invention, the receiving buffer is characterized in that data processing is performed in units of SDUs.

In addition, the present invention, when performing data transmission and reception processing in the radio link control (RLC) AM mode, (a). Configuring the SDUs from the higher into PDUs and adding headers to store the AMD PDUs in the transmit buffer, (b). Setting a predetermined field of the PDU header stored in the transmission buffer and transmitting the encrypted field; (c) decrypting the encrypted AMD PDU transmitted from the transmitting end and storing it in the receiving buffer, (d). Removing headers and piggyback information from the AMD PDUs stored in the reception buffer, extracting only data, configuring SDUs, and then reassembling and transmitting the data to the upper level; A data transmission / reception processing method in a recognition mode (AM) of a radio link control (RLC), characterized in that the processing.

The present invention proposes a new structure as shown in FIG. 5 to solve the problem of conventional ciphering / deciphering in the RLC AM entity.

According to the RLC AM entity structure of the present invention, at the transmitting end, a ciphering step is performed after a set fields block, and at the receiving end, a deciphering step is performed at a front end of a receiving buffer. Characterized in that made.

In the encryption step, only the AMD PDU is encrypted by checking the D / C field.

The transmission process of the AMD PDU in the RLC AM entity structure of the present invention is as follows.

First, at the transmitting side, the SDUs descending from the upper side are segmented or concatenated as in the conventional method (step 401), and a PDU is added by adding a header including a sequence number SN. (Step 402), the header-added PDUs are sent down and stored in a retransmission buffer 403 at the same time.

The PDUs down through the multiplexer 404 are stored in the transmission buffer 405 unencrypted, and the PDUs stored in the transmission buffer are then transmitted to the set fields block 406. .

Set fields block 406 sets the D / C field and other fields to the appropriate values, looks at the AMD PDU and replaces it with a piggybacked PDU if there is one, then sends it down. Encryption is performed before transmission to the receiving end (step 407).

At this time, before the encryption, the header D / C field of the AMD PDU is examined, and encryption is performed only for the AMD PDU including the piggybacked state PDU according to the D / C field value as described above, and the encryption is performed for the control PDU. Do not perform.

The transmitted PDU determines whether it is a control PDU or an AMD PDU through a D / C field check at a demultiplexing / routing unit 408 of a receiving side, and the control PDU is an RLC control unit. In step 400, the AMD PDU is transmitted to a decoding block 409.

In this case, after decryption, the AMD PDU is finally stored in the receiver buffer 410. When all PDUs constituting one complete SDU are received, the AMD PDU is transmitted to the upper unit in the SDU unit. After removing the RLC header and piggybacked information from each PDU in the header removal and piggyback information removal step 411, and extracting only data to configure the SDU, the reassembly process 412 is followed by a higher level. Will be sent to.

In other words, the difference between the structure of the present invention and the conventional structure is that in addition to the positions of encryption and decryption, unencrypted PDUs are stored in the transmission buffer and the reception buffer, and the D / C field is checked during encryption. .

Since the unencrypted PDUs are stored in the transmission buffer and the reception buffer, the transmission buffer and the reception buffer do not need the decryption function.

According to the present invention, since the encryption and decryption functions, which have not been used in the past, are unnecessary in the transmission buffer, the field setting block, and the reception buffer, the PDU processing time in the RLC layer can be shortened.

In addition, the present invention can easily process a piggyback state PDU, which was difficult to process in the conventional method. In addition, since the received buffer stores unencrypted (ie, decrypted) PDUs, it is possible to take full advantage of the other functions of the RLC processing in units of SDUs. These advantages increase data processing speed in RLC and enable more stable operation.

Claims (5)

When performing data transmission / reception processing in the radio link control (RLC) AM mode, (a). Configuring the SDUs from the higher into PDUs and adding headers to store the AMD PDUs in the transmit buffer, (b). Setting a predetermined field of a PDU header stored in the transmission buffer and transmitting the encrypted field; And a data transmission processing method in a recognition mode AM of a radio link control (RLC) of a wireless communication device. When performing data transmission / reception processing in the radio link control (RLC) AM mode, (a). Decrypting the encrypted AMD PDU transmitted from the transmitting end and storing it in the receiving buffer, (b). Removing headers and piggyback information from the AMD PDUs stored in the reception buffer, extracting only data, configuring SDUs, and then reassembling and transmitting the data to the upper level; And a data reception processing method in a recognition mode AM of a radio link control (RLC) of a wireless communication device. When performing data transmission / reception processing in Radio Link Control (RLC) AM mode, the transmitting side wireless communication apparatus (a). Configuring the SDUs from the upper layer into PDUs and adding headers to store the AMD PDUs in the transmit buffer, (b). Setting a predetermined field of the PDU header stored in the transmission buffer and transmitting the encrypted field; (c) decrypting the encrypted AMD PDU transmitted from the receiving wireless communication device and storing the decrypted AMD PDU in the receiving buffer; (d) . Removing headers and piggyback information from the AMD PDUs stored in the reception buffer, extracting only data, constructing an SDU, and reassembling and transferring the data to an upper layer; Data transmission and reception processing method in the recognition mode (AM) of the radio link control (RLC) of the wireless communication system, characterized in that made. A block configured to divide or connect a service data unit (SDU) delivered from an upper layer into a protocol data unit (PDU), a transmission buffer for temporarily storing the protocol data unit (PDU), and the protocol stored in the transmission buffer A recognition mode (AM) comprising a block for setting a predetermined field of a header of a data unit (PDU), and a block for encrypting and transmitting a protocol data unit (PDU) in which a predetermined field of the header is set to be transmitted to a lower layer. And a radio link control (RLC) entity structure. A block for decrypting and receiving an encrypted protocol data unit (PDU) transmitted from a lower layer, a receiving buffer for storing the decrypted protocol data unit (PDU), and a protocol data unit (PDU) stored in the receiving buffer Radio link control (RLC) in recognition mode (AM), which includes a block for removing header information from the header information and extracting the data, and a block for reassembling the protocol data unit (PDU) from which the header information is removed and delivering the data to a higher layer. A wireless communication device having an entity structure.