KR100782208B1 - Mobile station RLC capacity control method in BTRN - Google Patents

Abstract

The present invention relates to a mobile station RLC capacity control method in UTRAN for effectively controlling the RLC Capability of a UE (mobile station) to prevent an error in which data exceeds a buffer.

The present invention provides a method for controlling mobile station RLC capacity in a UTRAN, comprising: transmitting mobile station capacity information from a transmitting end (UE) to a receiving end (UTRAN); Storing the transmitted information in a UTRAN; When configuring a new radio carrier (RB), the transmission / reception window size and the PDU size may be determined by considering or simultaneously considering the header size of the AMD PDU or the retransmission buffer size of the transmitter.

Therefore, according to the present invention, the UTRAN accurately considers the RLC capability of the UE to prevent data loss and allow the protocols to operate stably.

UTRAN, UE, Capacity, Header, Retransmission, Buffer, AM Mode

Description

Mobile station RLC capacity control method in BTAN {Method for UTRAN to control UE RLC capability}             

1 is a view showing an RLC AM entity structure applied to the prior art and the present invention

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

The present invention relates to data transmission and reception of a recognition mode (AM) entity structure of a 3GPP RLC layer. In particular, the UTRAN effectively controls the RLC capability of a UE (mobile station) so that data exceeds a buffer. The present invention relates to a mobile station RLC capacity control method in UTRAN to prevent errors.

In particular, in the present invention, when UTRAN determines transmission / reception window size and PDU size when setting up a new radio bearer (RB), it is determined by considering the header of the AMD PDU of 2 bytes or retransmission buffer of the transmitting end. (Retransmission buffer) can be determined in consideration of, and also relates to a method for controlling the mobile station RLC capacity in the UTRAN in consideration of both the header of the 2-byte AMD PDU and the retransmission buffer of the transmitter.

More particularly, the present invention relates to a mobile station (UE) from a mobile station (UE) to a UTRAN in data transmission and reception between a mobile station (UE), a base station and a control station, and a universal area radio access network (UTRAN) including a control station manager for managing the control station. After transmitting the capacity information, the UTRAN stores the transmitted information and separately considers the header size of the AMD PDU or the retransmission buffer size of the transmitter (mobile station) among the stored information when setting up a new RB or AMD PDU. A method for controlling the RLC capacity of a mobile station in a UTRAN that determines both a transmit / receive window size and a PDU size in consideration of both a header size and a retransmission buffer size of a transmitting end (mobile station).

The Universal Terrestrial Radio Access Network (UTRAN) includes a base station (BTS), a control station (BSC), and a control station manager (BSM) that manages the control station. User equipment) may be referred to as a mobile station in a mobile communication system.

Hereinafter, a method of controlling a mobile station (UE) RLC capacity in a conventional UTRAN will be described.

First, the radio link control (RLC) layer referred to in the present invention is a second layer of 3GPP, a protocol layer for controlling data link, and corresponds to a second layer of the OSI 7 layer model.

There are two types of RLC entities used in 3GPP: Tr mode without RLC header and non-transparent mode with NTR.

The NTr mode is a UMD PDU (Unacknowledged Mode PDU) that is used when a receiver receives a PDU (Protocol Data Unit) again and then does not need to transmit an acknowledgment signal (ACK) to the transmitter. There are two types of PDUs that are used AMD (or AM) Acknowledged Mode PDUs (PDUs).

In general, in a mobile communication system, in order to transmit and receive data between the UE and the UTRAN, the UE needs to inform its UTRAN of its capacity, which is called a UE capacity update procedure.

The UE capability update procedure is mainly caused by three factors.

First, when a UE in idle mode wants to establish a connection with UTRAN (Radio Resource Control; Layer 3, which is in charge of 3GPP control plane),

Second, if the UTRAN requires the UE to transmit UE capability information as needed (UE capability enquiry);

Third, it can be divided into the case that the UE wants to inform the UTRAN by detecting the change of capability by itself.

In this case, since UE capability information informed by the UE to the UTRAN becomes an important criterion for managing the UE in the future, the UE needs to accurately inform its capability information.

The UE capability information contains various information related to the UE, for example, PDCP (Packet Data Convergence Protocol; 2nd layer in charge of packet transmission of 3GPP) capability and RLC (Radio Link Control; data link control of 3GPP). Second layer) capability, transport channel capability, physical channel capability, RF capability, and the like.

The UE RLC capability is one of them. The UE specifically informs UTRAN of the following three pieces of information.

1) Total RLC AM buffer size

2) Maximum RLC AM window size

3) Maximum number of AM entities

As described above, the AM (Acknowledge Mode) is one of three operating modes (AM, UM, Tr) of the RLC, and unlike other modes, performs a retransmission function, and the specific structure of the AM entity is shown in FIG. 1.

A method of operating an RLC AM will be described with reference to FIG. 1.

First, at the transmitting side (UE side), segmentation (con segmentation or concatenation) to make Service Data Units (SDUs) descending from the upper into a constant PDU (Protocol Data Unit) (step 101), A PDU is formed by adding a header including a sequence number (SN) and a length indicator indicating the boundary of the SDU (step 102), and the PDUs to which the header is added are transmitted downwards and retransmitted in the future. In order to be stored in a retransmission buffer 103.                         

The PDUs formed in step 102 are stored in the transmission buffer 105 in the unencrypted state of the PDUs down through the multiplexer 104, and the PDUs stored in the transmission buffer are then set in a field setting block (Set). fields block) 106.

In the Set fields block 106 above, the D / C field and other fields are set to appropriate values, and after examining the AMD PDU, if there is a PAD, it is replaced with a piggybacked state PDU and sent down. After that, encryption is performed and transmitted to the receiving end (UTRAN side) (step 107).

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 PDU carrying data information obtained from the upper layer is called an AMD (AM Data) PDU, and its structure is shown in FIG. 2.

First, a brief description of FIG. 2 includes the AMD header, the LI portion, and the data, and the AMD PDU inserts a piggyback type status PDU instead of padding to enable transmission.

In addition to the sequence number (SN) in the header of the AMD PDU, a 1-bit D / C field indicating whether the corresponding PDU carries data information or control information, and a status report is requested from the receiver. A P field, which is a 1-bit polling field, and a 2-bit HE (Header Extension) field indicating whether the next data is data or LI and E bits are added.

The PDU is based on ITU-T X.200 / ISO-IEC7498-1, and the SDU is based on ITU-T X.140.

More specifically, referring to FIG. 2, the AMD PDU header refers to the first 2 bytes including the SN, and the RLC header refers to a portion in which the bytes including the Length Indicator are added to the AMD PDU header.

In addition to these AMD PDUs, AM PDUs also contain Control PDUs that contain control information.There are three types of Control PDUs: Status PDUs containing status information, Reset PDUs for resetting AM entities, and Reset ACK PDUs for informing them. have.

These control PDUs are generated in the RLC control unit and transmitted to the set fields block where the D / C and PDU type fields are set and sent directly to the receiving end without ciphering.

That is, in the set fields block, 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 (hereinafter referred to as PAD) is performed.In the set fields block, when the AMD PDU has such a PAD, the status PDU can be filled instead of the PAD to improve the efficiency of data transmission. The Status PDU at this time is called a piggybacked Status PDU.

The AM entity PDU transmitted in this way determines whether it is a control PDU or an AMD PDU through D / C field inspection at the demultiplex / routing unit 108 of the receiving side (UTRAN). The PDU is transmitted to the RLC control unit 100 and the AMD PDU is transmitted to a decoding block 109.

Here, after the decoding is performed, the AMD PDU is finally transmitted to the receiver buffer 110. At this time, the reception buffer checks whether each PDU is received and sends a NACK signal to the transmitter to request retransmission for the unreceived PDU. Therefore, the PDUs stored in the reception buffer are transmitted to the upper level in the SDU unit when all the PDUs constituting one complete SDU are received. After removing the RLC header and piggybacked information from each PDU in the header removal and piggyback information removal step 111 and extracting only data to configure the SDU, the reassembly process 112 is performed through the upper layer. Will be sent to.

That is, the RLC AM information that the UE (transmitter) informs the UTRAN (receiver) is

1) How many RLC AM entities the UE allows as shown in FIG. 1 (Maximum number of RLC AM entities),

2) What is the total sum of Transmission and Receiver buffers that the UE can allocate for all RLC AM entities (Total RLC AM buffer size),

3) It also tells the maximum window size (calculated in units of PDU) that the maximum window size is used to transmit / receive PDUs for each AM entity.

As such, the AM needs to support the retransmission function, so a buffer and a window are required. Accordingly, unlike other modes, the RLC AM related information of the UE is managed specially in UTRAN.

The UTRAN, which received the RLC AM information from the UE, stores it and, based on this, when a new radio bearer (RB) is set, calculates the transmit / receive window size and PDU size of the RLC AM to be used for actual transmission. The decision is made to satisfy (1).

In the above i is the number of each RLC AM entity configured in the UE, AMD header size is 2 bytes.

That is, when configuring a new RB, the UTRAN should satisfy Equation (1) in consideration of all RLC AM entities and newly created RLC AM entities used up to that time.

If the window size and PDU size to be used in the new RB do not satisfy the above Equation (1), the PDUs overflow the buffer when there is a lot of data, which leads to data loss.

Therefore, the UTRAN must select a window size and a PDU size satisfying Equation (1), and inform the UE of the determined values.                         

However, the following problems may occur when using the conventional method as described above.

First, in comparing the transmit / receive window and the PDU size to the Total RLC AM buffer size, the conventional method does not consider the AMD header size, which is the first 2 bytes of each PDU, when calculating the buffer usage.

However, in practice, as shown in FIG. 1, since the PDU including the AMD header is stored in the transmission / reception buffer, the header size of the 2 bytes must also be considered.

For example, if the UE has one RLC AM entity and the Total RLC AM buffer size is 56 kbytes (1 kbyte = 1000 byte), the Tx window size = 2000 and UL (Uplink) PDU for the newly set RB by UTRAN If size = 15 bytes, Rx window size = 1000, DL (Down Link) PDU size = 30 bytes, the conventional method as shown in Equation 1 above

56,000byte를 만족하게 되므로 window size와 PDU size를 할당하게 된다. 2000 * (15-2) + 1000 * (30-2) = 54,000 bytes

Since 56,000 bytes are satisfied, the window size and the PDU size are allocated.

However, since the header of each AMD PDU is also stored in the buffer, the actual buffer usage is 2000 * 15 + 1000 * 30 = 60,000 bytes, which is larger than 56 kbytes, which is the total RLC AM buffer size. Since it is not satisfied, overflow of buffer occurs.

Second, the conventional method does not consider the retransmission buffer of the Tx RLC AM entity.

As described above, in the AM, PDUs are simultaneously stored in both a transmission buffer and a retransmission buffer for retransmission.

Therefore, the retransmission buffer must also be considered when calculating the total RLC AM buffer size.

However, since the retransmission buffer is not considered in the conventional method, it may cause a large error in calculating the actual buffer usage of the UE.

Therefore, the present invention is to propose a new standard for UTRAN to manage the RLC capability in order to solve the above problems, the UTRAN determines the transmission and reception window size and PDU size required for the setup of a new radio carrier (RB) In this regard, we propose a method of considering AMD Header or Retransmission buffer separately stored in the buffer and a method of determining the AMD Header and Retransmission buffer simultaneously.

The present invention relates to a mobile station RLC capacity control method in UTRAN for error-free processing of data transmission and reception between a mobile station (UE) and a universal area radio access network (UTRAN) including a base station and a control station and a control station manager managing the control station. Regarding, transmitting the mobile station capacity information from the transmitting end (mobile station) to the receiving end (UTRAN); Storing the transmitted information in a UTRAN; When configuring a new radio carrier (RB), the transmission / reception window size and the PDU size may be determined by considering or simultaneously considering the header size of the AMD PDU or the retransmission buffer size of the transmitter.

In addition, in the present invention, when UTRAN determines the transmit / receive window size and PDU size required for setting a new RB, the UE's actual buffer usage calculation formula considering only the AMD header is

If only retransmission buffer is considered, the actual buffer usage calculation formula of UE is

In case of considering AMD Header and Retransmission buffer at the same time, the actual buffer usage calculation formula of UE is

It is characterized by being.

Other objects and features of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, a method of controlling a mobile station (UE) RLC capacity in a UTRAN for preventing an error exceeding a buffer by effectively controlling the RLC capacity of a UE (mobile station) according to the present invention will be described with reference to the accompanying drawings. .

Since the components and operations of FIGS. 1 and 2 are equally applicable to the present invention, UTRAN proposed by the present invention will be considered below to determine the transmission / reception window size and PDU size required for a new radio carrier (RB) setup. The following description will focus on.

First, when UTRAN determines only the transmit / receive window size and PDU size required for a new RB setup, the actual buffer usage calculation of the UE when considering only the AMD Header (FIG. 2) actually stored in the buffer is as follows.

Therefore, if there is one RLC AM entity of the UE, and the UTRAN determines Tx window size = 2000, UL PDU size = 15 bytes, Rx window size = 1000, and DL PDU size = 30 bytes for the newly set RB, in the present invention, As shown in Equation 2

Since 2000 * 15 + 1000 * 30 = 60,000bytes, the total RLC AM buffer size should be at least 60,000 bytes to prevent buffer overflow when transmitting and receiving data between the UE and UTRAN.

Second, in determining the transmission / reception window size and PDU size required for a new RB setup, the UTRAN calculates the actual buffer usage of the UE when considering only the retransmission buffer (103 in FIG. 1).

In Equation 3, the reason for doubling the product of the transmission window size and the PDU size is to consider the retransmission buffer.

As described above, since the AMD PDU is simultaneously stored in both the transmission buffer and the retransmission buffer, the two buffers are generally set to the same size.

Therefore, if there is one RLC AM entity of the UE and the UTRAN determines Tx window size = 2000, UL PDU size = 15 bytes, Rx window size = 1000, and DL PDU size = 30 bytes for the newly set RB, in the present invention, As shown in Equation 3 above

Since 2 * 2000 * (15-2) + 1000 * (30-2) = 80,000bytes, the total RLC AM buffer size should be at least 80,000 bytes to prevent overflow of the buffer during data transmission and reception between the UE and UTRAN. .

Third, when UTRAN decides the transmission / reception window size and PDU size required for a new RB setup, the actual UE is considered when the AMD Header (FIG. 2) and the Retransmission buffer (103 in FIG. 1) are actually stored in the buffer. The buffer usage calculation is as follows.

Therefore, if there is one RLC AM entity of the UE, and the UTRAN determines Tx window size = 2000, UL PDU size = 15 bytes, Rx window size = 1000, and DL PDU size = 30 bytes for the newly set RB, in the present invention, As shown in Equation 4

Since 2 * 2000 * 15 + 1000 * 30 = 90,000bytes, the total RLC AM buffer size should be at least 90,000 bytes to prevent buffer overflow when transmitting and receiving data between the UE and UTRAN.

As described above, in the present invention, in the transmission and reception of data between a mobile station (UE), a base station and a control station, and a universal area radio access network (UTRAN) including a control station manager for managing the control station, the mobile station (UE) from the mobile station (UTRAN) After transmitting the capacity information, the UTRAN stores the transmitted information and separately considers the header size of the AMD PDU or the retransmission buffer size of the transmitter (mobile station) among the stored information when setting up a new RB or AMD PDU. The present invention relates to a mobile station RLC capacity control method in a UTRAN that determines both a transmission / reception window size and a PDU size in consideration of both a header size and a retransmission buffer size of a transmitting end (mobile station).

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments.

Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

Since the transmission buffer and the AMD header are not considered when determining the transmission / reception window size and the PDU size, the UE may receive data exceeding the total RLC AM buffer size, resulting in data loss.

In addition, even when performing functions such as radio bearer reconfiguration (reconfiguration) according to the buffer usage, it is possible to cause a big error in the protocol because it has a buffer usage of the wrong UE.

Therefore, according to the method proposed in the present invention, the UTRAN accurately considers the RLC capability of the UE to prevent data loss and allow the protocols to operate stably.

Claims (2)

In the data transmission and reception between a mobile station (UE), a base station and a control station and a universal area radio access network (UTRAN) comprising a control station manager for managing the control station, Transmitting mobile station capacity information from a transmitting end (mobile station) to a receiving end (UTRAN); Storing the transmitted information in a UTRAN; When establishing a new radio carrier (RB), the transmit / receive window size and PDU size are determined by considering or simultaneously considering the header size of the AMD PDU or the retransmission buffer size of the transmitting end of the stored information. A method for controlling mobile station RLC capacity in UTRAN. The UE formula calculation method according to claim 1, wherein the UTRAN calculates a transmission / reception window size and a PDU size required for setting a new RB. silver,

If only retransmission buffer is considered, the actual buffer usage calculation formula of UE is

When the AMD PDU header and the retransmission buffer are considered at the same time, the actual buffer usage calculation formula of the UE is

A method for controlling mobile station RLC capacity in UTRAN, characterized in that.

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