KR20110055850A - Method and apparatus for transmitting and receiving data in a mobile communication system - Google Patents

Abstract

PURPOSE: A data transmission/reception method and apparatus thereof in a mobile communication system are provided to minimize malfunction of an RLC layer due to delay transmission of PDU. CONSTITUTION: An RLC transmitter transmits an RLC PDU(Radio Link Control Protocol Data Unit)(1) to an RLC receiver(301). An RLC PDU is generated by the application of a new parameter. The RLC transmitter transmits the RLC PDU to the RLC receiving side(305). The RLC receiving side receives the RLC PDU. The RLC transmission side removes an RLC PDU after resetting RLC at T1 point.

Description

METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA IN A MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to an apparatus and method for transmitting and receiving data when RLC re-establishment occurs.

In general, the Universal Mobile Telecommunication Service (UMTS) system is based on the European mobile communication system Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), and has wideband-code division multiple access. : Third generation asynchronous mobile communication system using W-CDMA.

The 3rd Generation Partnership Project (3GPP), which is in charge of UMTS standardization, is discussing Long Term Evolution (LTE) as the next generation mobile communication system of UMTS systems. LTE is a technology that implements high-speed packet-based communication of about 100 Mbps, aiming for commercialization in 2010. To this end, various schemes are discussed. For example, a scheme of reducing the number of nodes located on a communication path by simplifying a network structure, or approaching wireless protocols as close as possible to a wireless channel are under discussion.

1 is a block diagram illustrating an example of a structure of an LTE mobile communication system.

Referring to FIG. 1, an Evolved Radio Access Network (E-RAN) 110 may include an Evolved Node B (hereinafter referred to as an 'ENB' or 'Node B') 120, 122, 124, 126, 128, hereinafter referred to as '120 through 128', and an upper node 130 (anchor node) 130, 132.

The user equipment (hereinafter referred to as "UE") 101 is connected to the Internet Protocol (hereinafter referred to as "IP") network by the E-UTRAN 110.

The ENBs 120 to 128 correspond to existing Node Bs of the UMTS system and are connected to the UE 101 by a radio channel. Unlike the existing Node B, the ENBs 120 to 128 play a more complex role. In LTE, all user traffic, including real-time services such as Voice over Internet Protocol (VoIP) over the Internet protocol, is serviced through a shared channel, which requires a device for gathering and scheduling situation information of UEs. The ENBs 120-128 are in charge.

Similar to High Speed Downlink Packet Access (HSDPA) or Enhanced-Dedicated Channel (E-DCH), LTE AR (Hybrid ARQ) is performed between ENBs 120 to 128 and UE 101, but HARQ alone provides various quality of service ( Quality of Service (QoS) cannot meet the requirements, so that an outer ARQ may be performed at a higher layer, and the separate ARQ is also between the UE 101 and the ENBs 120 to 128. Is performed in

In order to realize transmission rates of up to 100 Mbps, LTE systems are expected to use Orthogonal Frequency Division Multiplexing (OFDM) as a radio access technology in the 20 MHz bandwidth. The LTE system uses an adaptive modulation & coding (AMC) scheme that determines a modulation scheme and a channel coding rate according to a channel state of a terminal.

Meanwhile, the W-CDMA standard is approved by the 3rd Generation Partnership Project (3GPP) and is in the Release stage according to the adopted technology. In principle, the upper release guarantees backward compatibility.

In a wireless mobile communication technology such as W-CDMA, data loss may occur due to signal degradation in a wireless section. Therefore, a reliable data transmission and reception method between a receiver and a transmitter is required.

In order to compensate for signal degradation on a physical radio channel of a transmitter and a receiver, power control is required, and a protocol for reliable transmission and reception in a transport layer is required.

Therefore, in W-CDMA, a protocol called RLC (Radio Link Control) is provided to secure a reliable data transmission method between a transmitter and a receiver. In particular, in the case of an Acknowledgment Mode (AM) RLC, various procedures and a Control PDU (Protocol Data Unit) are used for in-sequence delivery in a sequence number (hereinafter referred to as 'SN') order.

One) RLC PDU  Size and Length Indicator ( LI ) size

PDUs used by the AM RLC layer are largely classified into Acknowledge Mode Data (AMD) PDUs and Control PDUs.

The AMD PDU consists of a header containing information such as SN and a length indicator indicating the configuration status of the data field, in addition to the data field containing the data of the actual upper layer (Length Indicator: hereinafter referred to as 'LI'). One LI field has a size of 7 bits or 15 bits. Control PDUs do not include LI, and the remainder of the PDUs are considered padding except those that are validly interpreted according to predefined rules.

In the specification up to Release 6, the RLC PDU size is fixed and its value is set in the upper layer. The size of the LI is determined by the size of the determined PDU, and for AMD PDUs, 7-bit LI should be used if the PDU size is 126 bytes or less, and 15-bit LI if it exceeds 126 bytes. However, the higher layer specification implicitly assumes that only 7-bit LI is used when using a fixed RLC PDU size, and the terminal common environmental test specification does not describe that 15-bit LI should be used when using a fixed RLC PDU size.

In the Release 7 specification, the RLC PDU size can be set to fixed or flexible for downlink. When using a fixed size, the method of setting the RLC PDU size and determining the LI size is the same as the previous specification. When using a variable size, the upper layer sets the length indicator size (LI size) to 7-bit or 15-bit instead of the PDU size, and the RLC layer sets the size of the configured LI size and the service data unit (SDU) to be transmitted. The PDU is configured in consideration of the size. In this case, the size of the PDU may change at every PDU generation.

2) RLC  Condition to perform reset function

The RLC layer can perform the RLC reset function under the control of the upper layer, and the upper layer determines the execution time through the signaling procedures of each other. When the RLC reset function is performed, the RLC layer may initialize prescribed state variables, apply a parameter set in a higher layer, and additionally perform a specific operation according to a predetermined condition.

The conditions for executing the RLC reset function in the upper layer and the problem when the RLC reset function is not performed are as follows.

(1) If the downlink RLC PDU size is fixed and you want to change the PDU size different from the current PDU size, the PDU size is changed in the RLC layer using the fixed RLC PDU size. There is a problem that is difficult to receive correctly.

(2) If the downlink RLC PDU size is variable and you want to change it to a different LI size than the current LI size, there is a problem that incorrect PDU interpretation and RLC layer malfunction occur because the LI interpretation rule is changed.

(3) If the downlink RLC PDU size is to be changed from the current variable to the fixed, the RLC layer using the fixed RLC PDU size cannot accommodate the PDU of the variable size.

(4) When the downlink RLC PDU size is changed from the current fixed to the variable whose LI size is 15-bit, the LI interpretation rule is changed, thereby causing an incorrect PDU interpretation and an RLC layer malfunction.

On the other hand, in the following conditions, only RLC layer parameters are changed without performing the RLC reset function. In this case, the PDUs created and transmitted through the parameters before the change are applied at the peer entity. There is no need to perform the RLC reset function because it can be guaranteed to receive and interpret correctly.

(5) If you want to change the downlink RLC PDU size from current fixed to variable with 7-bit LI size, the RLC layer using the variable size can accommodate the fixed size PDU and change the parameter because the LI size has not changed. Even older PDUs have no problem with interpretation. This condition is possible because the implicit assumption is that the LI size uses only 7-bit when using a fixed RLC PDU size.

In other words, as can be seen from the conditions listed above, the RLC reset function is required to change the RLC layer parameters. If the RLC is not sure that the PDU generated by applying the previous parameters can be correctly received and interpreted by the large station after the parameter change, the RLC After initializing the layer, the purpose is to change parameters to create a new PDU and resume transmission.

When the RLC reset function is performed, the RLC layer state variables are initialized and new parameters are set. Therefore, processing the PDU generated before performing the RLC reset function after performing the function may cause an RLC layer malfunction. Conventionally, in consideration of this, it is prescribed to discard AMD PDUs and STATUS PDUs (a kind of Control PDU) that are waiting for processing in the RLC layer at the time of performing the RLC reset function. However, the prior art does not consider PDUs remaining in the transmission interval without reaching the RLC layer at the time of performing the RLC resetting function.

The present invention provides a method and apparatus for minimizing an RLC malfunction that may be received by an RLC layer after a RLC resetting time due to a transmission interval delay.

According to an embodiment of the present invention, a method of transmitting data in a mobile communication system includes transmitting a first PDU to a receiving side, and transmitting the first PDU from the transmitting side to the receiving side. Determining a transmission prohibition time in consideration of the time taken to transmit the), and stopping the second PDU transmission from the time when the transmission prohibition time is subtracted from the RLC reset time until the RLC reset time, and after the transmission prohibition time And transmitting the second PDU to the receiving side.

According to an embodiment of the present invention, a method of a receiving side in a mobile communication system includes: receiving a first packet data unit (PDU) from a transmitting side, and transmitting the received data from the transmitting side to the receiving side; Determining the reception prohibition time in consideration of the time taken for the first PDU to be received; stopping the reception of the second PDU from the RLC resetting time point to the time when the prohibition time is added to the RLC resetting time point; Receiving the second PDU from the transmitting side.

The present invention can minimize the RLC layer malfunction due to delayed transmission of the PDU before the RLC reset time point to prevent network quality degradation immediately after performing the RLC reset function.

In addition, the present invention can minimize the RLC layer malfunction due to delayed transmission of the PDU before the RLC resetting time, even if applied to only one side of each RLC layer.

In addition, the present invention can increase the transmission efficiency by preventing the loss of transmission data when the RLC reset occurs in the mobile communication system.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The main idea of the present invention is to minimize the RLC layer malfunction due to delayed transmission of the PDU before the RLC reset point. In the first embodiment of the present invention, the transmitting side transmits the first PDU, and then determines the transmission prohibition time of the packet to be transmitted, and transmits the second PDU in consideration of the determined transmission prohibition time. In the second embodiment of the present invention, the receiving side receives the first PDU, and then determines the reception prohibition time of the received packet, and receives the second PDU in consideration of the determined reception prohibition time. Accordingly, the present invention can minimize RLC layer malfunction due to delayed transmission of the PDU before the RLC resetting time, even if applied only to one side of each RLC layer.

Although the present invention is designed based on the 3GPP Release 7 standard, it is to be noted that the present invention is not limited to the Release 7 standard and may be applied to both upper and lower standards.

2 is a flowchart illustrating a method of transmitting a PDU before a general RLC reset. That is, FIG. 2 illustrates a PDU transmission method between RLC stations.

The RLC layer transmitting the PDU at a specific time point will be referred to as the RLC transmitting side 210, and the RLC layer receiving the PDU will be referred to as the RLC receiving side 200.

The RLC transmitter 210 transmits the RLC PDU 1 to the RLC receiver 200 in step 201. The time required for the RLC receiving side 200 to receive the RLC PDU 1 will be referred to as TTA (Time To Arrival). After the RLC transmitting side 210 transmits the RLC PDU 2 to the RLC receiving side 200 in step 203, the RLC resetting 205 is performed before the RLC PDU 2 is received at the RLC receiving side 200. In this case, there is a problem that a malfunction may occur in the RLC receiving side 200 that receives the RLC PDU (2).

The present invention proposes a scheme of each of the transmitting / receiving side RLC layers in consideration of the above points.

One) RLC PDU Sending side  action

3 is a flowchart illustrating a method of transmitting a PDU before resetting an RLC according to a first embodiment of the present invention. That is, FIG. 3 shows a PDU transmission method between RLC stations.

As in FIG. 2, an RLC layer transmitting a PDU at a specific time point is referred to as an RLC transmitting side 210 and an RLC layer receiving a PDU is referred to as an RLC receiving side 200.

For example, a STATUS PDU including MRW_ACK SUFI (Moving Receiving Window ACK Super-Field) is transmitted by the receiver in the specification and received by the sender. In the present invention, in this case, the RLC layer that transmits the PDU, that is, a layer named Receiver in the standard, is called an RLC transmitter.

The RLC transmitter 210 transmits the RLC PDU 1 to the RLC receiver 200 in step 301. Thereafter, the RLC transmitting side 210 takes time until the RLC receiving side 200 receives the RLC PDU 1 in order to block the possibility that the RLC receiving side 200 malfunctions due to the delayed PDU. The transmission prohibition time (T_PRX_TX_PDU) is determined in consideration of the TTA (Time To Arrival). The transmission prohibition time T_PRX_TX_PDU includes a function value derived from a constant considering the TTA or a TTA.

In addition, the RLC transmitter 210 stops transmitting the RLC PDU 2 during the transmission prohibition time. That is, the upper layer of the RLC transmitting side 210 notifies the RLC transmitting side 210 that the RLC resetting time is determined to be T1. In addition, the transmitting side RLC layer 210 stops the PDU transmission 2 from the T1-transmission prohibition time (T_PRX_TX_PDU) to the time T1.

If the RLC reset is performed at the time point T1, the RLC transmitter 210 determines the RLC PDU 2 at this point (in this case, from the time when the transmission prohibition time is subtracted from the RLC reset time point until the RLC reset operation time point). (Discard). After the RLC reset time, the RLC PDU 2 'generated by applying the new parameter may be transmitted from the RLC transmitting side 210 to the RLC receiving side 200 in step 305, and the RLC receiving side 200 may transmit the RLC PDU. (2 ') can be received normally.

2) RLC PDU Receiving side  action

4 is a flowchart illustrating a method of receiving a PDU before RLC resetting according to a second embodiment of the present invention. 4 illustrates a method for receiving PDUs between RLC stations.

2 and 3, an RLC layer transmitting a PDU at a specific time point is referred to as an RLC transmitting side 210 and an RLC layer receiving a PDU is referred to as an RLC receiving side 200.

When the RLC transmitter 210 does not operate according to the first embodiment of the present invention, if the RLC transmitter 210 transmits the RLC PDU 2 without considering the time of performing the RLC reset, after performing the RLC reset The RLC receiving side 200 may receive the RLC PDU 2, and if this is regarded as a normal PDU and processed, it may cause a malfunction of the receiving side.

Therefore, the second embodiment of the present invention proposes a method for minimizing the possibility of malfunction by discarding the PDU received during the prohibition time (T_PRX_RX_PDU) immediately after the RLC receiving side performs the RLC reset.

First, the RLC receiving side 200 receives the RLC PDU 1 from the RLC transmitting side 210 in step 401. The RLC receiving side 200 determines the reception prohibition time (T_PRX_RX_PDU) 407 in consideration of a time to arrival (TTA), which is a time required for receiving the RLC PDU 1 from the RLC transmitting side 210. . The TTA includes a function value derived from a constant or TTA considering the TTA.

Even if the RLC receiving side 200 receives the RLC PDU 2 from the RLC transmitting side 210 in step 403, the RLC receiving side 200 discards the RLC PDU 2 received within the prohibition time after the time of performing the RLC resetting. The RLC reset is performed at the time T2 under the control of the upper layer of the RLC receiving side 200, and the RLC receiving side 200 ignores the PDU received from the time T2 to the time point (T2 + prohibition time T_PRX_RX_PDU). . The operation of ignoring the received PDU is stopped after (T2 + reception prohibition time T_PRX_RX_PDU).

After the prohibition of reception, the RLC receiving side 200 may normally receive the RLC PDU 3 from the RLC transmitting side 210 in step 405.

5 is a diagram illustrating a PDU transmission method in an RLC transmitting side according to a first embodiment of the present invention.

In step 501, the RLC transmitter 210 transmits a first RLC PDU to the RLC receiver 200. In operation 503, the RLC transmitting side 210 blocks the possibility that the RLC receiving side 200 malfunctions due to the delayed PDU. The RLC transmitting side 210 transmits the RLC receiving side 210 to the RLC receiving side 200. The transmission prohibition time (T_PRX_TX_PDU) is determined in consideration of a time to arrival (TTA), which is a time required for transmitting the RLC PDU. The transmission prohibition time T_PRX_TX_PDU includes a function value derived from a constant considering the TTA or a TTA as a factor. PDU transmission is stopped until the RLC resetting time from the time when the transmission prohibition time is subtracted from the RLC resetting time.

In operation 505, the RLC transmitter 210 transmits a second RLC PDU to the RLC receiver 200 after the RLC reset time from the time when the transmission prohibition time is subtracted from the RLC reset time.

6 is a diagram illustrating a PDU reception method at an RLC receiving side according to a second embodiment of the present invention.

As in FIG. 5, an RLC layer transmitting a PDU at a specific time point is referred to as an RLC transmitting side 210 and an RLC layer receiving a PDU is referred to as an RLC receiving side 200.

First, the RLC receiving side 200 receives the first RLC PDU from the RLC transmitting side 210 in step 601. In operation 603, the RLC receiving side 200 determines a reception prohibition time (T_PRX_RX_PDU) 407 in consideration of a time to arrival (TTA), which is a time required to receive the RLC PDU 1. The TTA includes a function value derived from a constant or TTA considering the TTA.

The RLC PDU reception is stopped from the RLC resetting time point T2 to the time point when the reception prohibition time is added in the T2, and the RLC receiving side after the time point at which the reception prohibition time is added in the T2 from the RLC resetting time point T2. 200 normally receives the second RLC PDU from the RLC sender 210 in step 605.

7 is a block diagram of a PDU transmitting and receiving apparatus to which the present invention is applied.

The RLC transmitter 210 includes a transmitter 760, a transmission prohibition time determiner 750, and a controller 740.

The transmission prohibition time determiner 750 may block the possibility that the RLC receiving side 200 malfunctions due to the delayed PDU, from the RLC transmitting side 210 to the RLC receiving side 200 to the first RLC. The transmission prohibition time (T_PRX_TX_PDU) is determined in consideration of a time to arrival (TTA), which is a time required to transmit a PDU. At this time, the transmission prohibition time includes a function value derived from a constant considering a time to arrival (TTA) or a time to arrival (TTA) as a factor.

The transmitter 760 transmits the first RLC PDU to the RLC receiving side 200, and then, after subtracting the transmission prohibition time from the RLC resetting time, the second RLC PDU after the RLC resetting time 200. ).

The first control unit 740 transmits a first PDU from the RLC transmitting side 210 to the RLC receiving side 200, determines a transmission prohibition time of a packet to be transmitted, and considers the determined transmission prohibition time. The transmitter 760 and the transmission prohibition time determiner 750 are controlled to transmit a second PDU.

Meanwhile, the RLC receiving side 200 includes a receiving unit 730, a prohibition time determining unit 720, and a second control unit 710.

The reception prohibition time determiner 720 considers a time to arrival (TTA) which is a time required for the RLC receiving side 200 to receive the RLC PDU 1 in FIG. 4 (T_PRX_RX_PDU) Determine (407).

The receiving unit 730 receives the first RLC PDU from the RLC transmitting side 210, and from the RLC resetting time T2 to the second RLC from the RLC transmitting side 210 after the time of adding the prohibition time in T2. Receive the PDU normally.

The second control unit 710 receives the first PDU, and then determines the reception prohibition time of the received packet, and determines the reception prohibition time to receive the second PDU in consideration of the determined reception prohibition time. The unit 720 and the receiver 730 are controlled.

1 is a block diagram illustrating an example of a structure of an LTE mobile communication system;

2 is a flowchart illustrating a method of transmitting a PDU before a general RLC reset;

3 is a flowchart illustrating a PDU transmission method before an RLC reset according to the first embodiment of the present invention;

4 is a flowchart illustrating a method of receiving a PDU before RLC reset according to a second embodiment of the present invention;

5 is a flowchart illustrating a method of transmitting a PDU before RLC reset according to a first embodiment of the present invention;

6 is a flowchart illustrating a method of receiving a PDU before RLC reset according to a second embodiment of the present invention;

Figure 7 is a block diagram of a PDU transmission and reception apparatus before the RLC reset to which the present invention is applied.

Claims (12)

In the data processing method at the transmitting side in a mobile communication system, Transmitting a first PDU to a receiving side; Determining a transmission prohibition time in consideration of the time taken to transmit the first packet data unit (PDU) from the transmitting side to the receiving side; Stopping the transmission of the second PDU from the time point when the transmission prohibition time is subtracted from the RLC resetting time point, and transmitting the second PDU to the receiving end after the transmission prohibition time; Way. The method of claim 1, The transmission prohibition time is, A data processing method at a transmitting side including a constant in consideration of TTA (Time TO Arrival). The method of claim 1, The transmission prohibition time is, A data processing method at a transmitting side including a function value derived from a TTA (Time TO Arrival). In the data processing method at the receiving side in the mobile communication system, Receiving a first packet data unit (PDU) from a transmitting side; Determining a reception prohibition time in consideration of the time taken for the first PDU to be received from the transmitting side to the receiving side; Stopping the reception of the second PDU from the RLC resetting time point to the time when the RLC resetting time is added to the time when the reception prohibition time is added, and receiving the second PDU from the transmitting end after the reception prohibition time; Way. The method of claim 4, wherein The reception prohibition time is, A data processing method at a receiving side including a constant considering a time to arrival (TTA). The method of claim 4, wherein The reception prohibition time is, A data processing method at a receiving side including a function value derived from a TTA (Time TO Arrival). In the data processing apparatus at the transmitting side in a mobile communication system, A transmission prohibition time determination unit for determining a transmission prohibition time in consideration of the time taken to transmit a first PDU (Packet Data Unit) from the transmitting side to the receiving side; Transmit the first PDU to the receiving side, stop transmitting the second PDU from the time of subtracting the transmission prohibition time from the RLC resetting time to the RLC resetting time, and transmit the second PDU to the receiving end after the transmission prohibition time. A data processing apparatus at the transmitting side comprising a transmitting unit for transmitting. The method of claim 7, wherein The transmission prohibition time is, A data processing apparatus at the transmitting side including a constant in consideration of TTA (Time TO Arrival). The method of claim 7, wherein The transmission prohibition time is, A data processing apparatus at the transmitting side including a function value derived from a TTA (Time TO Arrival). A data processing apparatus at a receiving side in a mobile communication system, A reception prohibition time determination unit for determining a reception prohibition time in consideration of the time taken for the first PDU (Packet Data Unit) to be received from a transmission side to the reception side; Receiving the first PDU from the transmitting side, and stops receiving the second PDU from the RLC resetting time to the time when the RLC resetting time plus the reception prohibition time, and after the reception prohibition time from the transmitting side to the second A data processing apparatus at a receiving side including a receiving unit for receiving a PDU. The method of claim 10, The reception prohibition time is, A data processing apparatus at a receiving side including a constant in consideration of a TTA (Time TO Arrival). The method of claim 10, The reception prohibition time is, A data processing apparatus at a receiving side including a function value derived from a TTA (Time TO Arrival).

Images