KR20080009470A - How to Process Control Information in Mobile Communication Systems - Google Patents

Abstract

The present invention relates to a method for processing control information, and more particularly, to a method for processing control information in a mobile communication system that prevents unnecessary waiting of a terminal. In order to achieve the above object, the present invention operates in a UM (Unacknowledged mode) mode, and is a protocol data unit (protocol) transmitted from a transmitting side a plurality of times by a radio link control (RLC) entity having a reception window and a timer. Receiving Data Units, but through one common logical channel; Rearranging the received protocol data units using a sequence number of the received protocol data unit, a reception window and a timer; Processing the rearranged protocol data units to reconstruct at least one service data unit; And delivering said at least one service data unit.

Description

Method for processing control information in mobile communication system

1 is a diagram illustrating a network structure of a universal mobile telecommunications system (UMTS).

2 is a diagram showing the structure of a radio protocol used in UMTS.

3 is a UM RLC operation of a receiving side according to the related art, and illustrates an operation when receiving an RLC PDU from a lower end.

4 is a flowchart illustrating an RRC connection procedure.

5 is a flowchart illustrating a reorganization procedure proposed in this embodiment.

The present invention relates to a method for processing control information, and more particularly, to a method for processing control information in a mobile communication system that prevents unnecessary waiting of a terminal.

1 is a diagram illustrating a network structure of a universal mobile telecommunications system (UMTS). The UMTS system is composed of a user equipment (UE), a UTMS radio access network (UTRAN), and a core network (CN). The UTRAN includes one or more Radio Network Sub-systems (RNS), each RNS having one Radio Network Controller (RNC) and one or more base stations (Node B) managed by the RNC. It consists of. One or more cells exist in one Node B.

2 shows a structure of a radio protocol used in UMTS. These radio protocol layers exist in pairs in the terminal and the UTRAN, and are responsible for data transmission in the radio section. Referring to each of the radio protocol layers, first, the PHY layer, which is the first layer, serves to transmit data in a radio section using various radio transmission technologies. The PHY layer is connected to the upper layer MAC layer through a transport channel, and the transport channel is largely divided into a dedicated transport channel and a common transport channel according to whether the channel is shared.

In the second layer, there are MAC, RLC, PDCP and BMC layers. First, the MAC layer serves to map various logical channels to various transport channels. It also plays the role of logical channel multiplexing, which maps multiple logical channels to one transport channel. The MAC layer is connected to the upper layer RLC layer by a logical channel, and the logical channel includes a control channel for transmitting information of a control plane according to the type of information to be transmitted. It is divided into a traffic channel that transmits user plane information.

The RLC layer is responsible for guaranteeing the quality of service (QoS) of each radio bearer (RB) and the transmission of data accordingly. RLC has one or two independent RLC entities per RB to guarantee unique QoS of RB. To support various QoS, TM (Transparent Mode) and UM (Unacknowledged Mode) are supported. And three RLC modes, namely, AM (Acknowledged Mode). In addition, the RLC adjusts the data size so that the lower layer is suitable for transmitting data in the wireless section. The RLC also divides and connects data received from the upper layer.

The PDCP layer is located above the RLC layer, so that data transmitted using an IP packet such as IPv4 or IPv6 can be efficiently transmitted in a radio section having a relatively low bandwidth. To this end, the PDCP layer performs a header compression function, which transmits only necessary information in a header portion of data, thereby increasing transmission efficiency of a wireless section. The PDCP layer exists only in the PS domain because header compression is a basic function. There is one PDCP entity per RB to provide effective header compression for each PS service.

In addition, in the second layer, a BMC (Broadcast / Multicast Control) layer exists above the RLC layer to schedule a cell broadcast message and broadcast to terminals located in a specific cell.

The RRC (Radio Resource Control) layer located at the bottom of the third layer is defined only in the control plane and controls the parameters of the first and second layers in connection with the setup, reset and release of the RBs, and also the logic. Responsible for control of channels, transport channels and physical channels. In this case, RB refers to a logical path provided by the first and second layers of the radio protocol for data transmission between the terminal and the UTRAN. In general, RB setup means a process of defining characteristics of a radio protocol layer and a channel required to provide a specific service, and setting each specific parameter and operation method. When the RRC layer of a specific terminal and the RRC layer of the UTRAN are connected to send and receive RRC messages with each other, the terminal is in an RRC connected state, and when the terminal is not connected, the terminal is in an idle state. ) State.

Hereinafter, the RLC layer will be described in more detail.

The basic function of the RLC layer is to guarantee the QoS of each RB and thus the transmission of data. Since the RB service is a service provided by the second layer of the radio protocol to the upper layer, the entire second layer affects QoS, but the influence of the RLC is particularly large. RLC has a separate RLC entity for each RB to guarantee RB-specific QoS, and transparent mode (abbreviated as TM) and unacknowledged mode (UM) for supporting various QoS. Three RLC modes, namely abbreviated) and acknowledged mode (hereinafter, abbreviated as AM). The three modes of the RLC differ in how they operate because of the different QoS that each supports, and their detailed functions are also different. Therefore, the RLC needs to be looked at according to its operation mode.

TM RLC is a mode in which no overhead is added to the RLC SDU received from the upper layer in constructing the RLC PDU. That is, it is called TM RLC because the RLC transparently passes the SDU. Due to this characteristic, the RLC plays the following roles in the user plane and the control plane. Since the data processing time in the RLC is short in the user plane, it is mainly responsible for the transmission of real-time line data such as voice or streaming in the circuit service domain (abbreviated as 'CS domain'), and in the control plane in the RLC. Since there is no overhead in the uplink, it is responsible for the transmission of the RRC message from the unspecified terminal in the case of Uplink, and the transmission of the RRC message broadcasted to all the terminals in the cell in the case of Downlink.

Unlike transparent mode (TM mode), the mode in which overhead is added in RLC is called non-transparent mode, and there are two types of acknowledgment non-response mode (UM) and response mode (AM) for transmitted data. There is a kind. The UM RLC attaches a PDU header including a sequence number (hereinafter abbreviated as SN) to each PDU, so that the receiver can know which PDU is lost during transmission. From the point of view of the transmitting side RLC, the transmitting side operating in the non-response mode does not check whether the receiving side has properly received the corresponding PDU, and thus, does not retransmit the PDU once transmitted. The receiving RLC operating in the non-response mode determines which PDU has been lost based on the serial number of the received PDU, and no longer expects to receive the PDU determined to be lost. Immediately upstream. For example, if a UM RLC received an RLC PDU with serial number 3 and then received an RLC PDU with serial number 6, the UM RLC failed to receive an RLC PDU with serial number 4 or serial number 5. Judging and do not expect to receive any more. Due to this function, UM RLC mainly transmits broadcast / multicast data in the user plane, or real-time packet data such as voice (eg VoIP) or streaming in a packet service domain (hereinafter, simply PS domain). The control plane is responsible for the transmission of the RRC message that does not require an acknowledgment of the RRC message transmitted to a specific terminal or a specific terminal group in the cell.

One of the non-transparent modes, AM RLC, like UM RLC, configures PDU by attaching PDU header including SN in PDU configuration.However, unlike UM RLC, receiving RAC responds to PDUs sent by sender. There is a big difference. The reason why the receiver responds in the AM RLC is to request the transmitter to retransmit the PDU that it did not receive. This retransmission function is the biggest feature of the AM RLC. After all, AM RLC aims to guarantee error-free data transmission through retransmission. Because of this purpose, AM RLC mainly prevents transmission of non-real-time packet data such as TCP / IP in the PS domain. In charge.

Hereinafter, the UM RLC will be described in detail.

UM RLC sets and manages the following environment variables.

VR (US) represents a next reception number. This value means the value immediately after the SN value of the last received RLC PDU. That is, if a value having an SN value of 'x' is received, VR (US) is set to 'x + 1'.

When the UM RLC of the sender receives an RLC SDU (Service Data Unit) from an upper end (for example, an upper layer of the UM RLC), the RLC SDUs may be cut or segmented to a suitable size. After creating the RLC PDU by sequentially assigning serial numbers to each of them, and delivers to the lower stage (for example, the lower layer of UM RLC). In addition, the UM RLC indicates a length indicator (hereinafter, abbreviated as 'LI') indicating a position of the boundary of the RLC SDU in the RLC PDU so that the receiver can properly recover the RLC SDU from the RLC PDU. Include it in

Here, SN (serial number) is represented by 7 bits. This is intended to improve the transmission efficiency of data to be actually delivered by reducing the header portion of each RLC PDU by simply expressing the SN. Therefore, the serial number transmitted in the actual RLC PDU is a value from 0 to 127. Accordingly, the transmitting side sequentially assigns serial numbers to each RLC PDU from 0, and uses 127 after assigning serial numbers. As in this case, it is said that wrap-around occurs when the serial number starts to be used again from a high value such as 127 to a low value such as 0. Therefore, the RLC PDUs after the wrap around has occurred are RLC PDUs that must be delivered after the RLC PDUs before the wrap around has occurred. The receiving side always checks the SN for the received RLC PDU. If the SN of the received RLC PDU is smaller than the last received RLC PDU, it is determined that wrap around has occurred. In addition, all RLC PDUs received after the wraparound occurrence are regarded as RLC PDUs generated after the previously received RLC PDUs.

3 is a UM RLC operation of a receiving side according to the related art, and illustrates an operation when receiving an RLC PDU from a lower end.

The receiving side receives the RLC PDU having the SN value (S300).

The VR (US) is reset according to the SN value of the received RLC PDU (S301).

If the update value of the VR (US) value is not 1 in the process of S301, it is determined that there is a lost RLC PDU (S302), and the RLC SDUs associated with the determined RLC PDUs are deleted (S303), and the update width is determined. If 1, the following process is performed.

 After the restoration process is performed using the successfully received RLC PDUs, the successfully completed RLC SDUs are transferred to an upper layer of the RLC (S304), and the process ends (S305).

Hereinafter, the RRC state and the RRC connection method of the UE will be described in detail. The RRC state refers to whether or not the RRC of the UE is in a logical connection with the RRC of the UTRAN. If the RRC state is connected, the RRC connected state (RRC connected state), if not connected, the RRC idle state (RRC idle) state).

 Since there is an RRC connection for the UE in the RRC connected state, the UTRAN may determine the existence of the corresponding UE in units of cells. Therefore, the terminal can be effectively controlled. However, the UE in the RRC idle state cannot be grasped by the UTRAN and is managed by a CN (core network) in units of a location area or a routing area, which is a larger area than a cell. In other words, the UE in the RRC idle state is only detected in a large area unit, and must move to the RRC connected state in order to receive a normal mobile communication service such as voice or data.

When the user first powers on the terminal, the terminal first searches for an appropriate cell and then stays in an RRC dormant state in that cell. When the UE in the RRC idle state needs to establish an RRC connection, the UE establishes an RRC connection with the RRC of the UTRAN through an RRC connection procedure and transitions to the RRC connected state. There are a number of cases in which the UE in the RRC idle state needs to establish an RRC connection. For example, when an uplink data transmission is necessary due to a user's call attempt or when a paging message is received from the UTRAN, Reply message transmission, and the like.

In order to establish an RRC connection with the UTRAN, the UE in the RRC idle state must proceed with an RRC connection procedure as described above. The RRC connection process is largely performed by the terminal to send an RRC connection request message to the UTRAN, the UTRAN to send an RRC connection setup message to the terminal, and the terminal to complete the RRC connection setup to the UTRAN. ) There are three stages of message transmission. This RRC connection process is shown in FIG.

First, an RRC connection request process (S401) will be described.

When the UE in the RRC idle state wants to establish an RRC connection due to a call attempt or a response to paging of the UTRAN, the UE first transmits an RRC connection request message to the UTRAN. In this case, the RRC connection request message includes an initial UE identity of the terminal, an RRC connection reason (Establishment cause), and the like. The initial terminal identifier is a terminal unique identifier, so that the terminal can be identified anywhere in the world. There are many reasons for RRC connection, such as a call attempt or paging response. The UE drives the timer at the same time as transmitting the RRC connection request message, and if the RRC connection setup message or the RRC connection reject message is not received from the UTRAN until the timer expires, the RRC connection request message Send it again. The maximum number of transmissions of an RRC connection request message is limited to a specific value.

Hereinafter, an RRC connection setup process (S402) will be described.

Upon receiving the RRC connection request message from the terminal, the UTRAN accepts the RRC connection request of the terminal when there are sufficient radio resources, and transmits an RRC connection setup message, which is a response message, to the terminal. At this time, the RRC connection setup message includes an initial terminal identifier and a radio network temporary identity (RNTI) and radio bearer setup information. The radio network temporary identifier is a terminal identifier allocated by the UTRAN to identify a terminal in an RRC connection state. The identifier is used only if an RRC connection exists and is also used only within the UTRAN. After the RRC connection is established, the terminal communicates with the UTRAN using the radio network temporary identifier instead of the initial terminal identifier. The initial terminal identifier is a unique identifier of the terminal, but if it is frequently used, there is a risk of leakage. Therefore, for security reasons, it is used only temporarily during the RRC connection process, and then the wireless network temporary identifier is used.

Hereinafter, an RRC connection setup complete process (S403) will be described.

The terminal receiving the RRC connection establishment message first compares the initial terminal identifier included in the message with its own identifier, and checks whether the received message is a message transmitted to the terminal. As a result of the check, if the message is transmitted to the terminal, the terminal stores the radio network temporary identifier assigned by the UTRAN and transmits an RRC connection setup complete message to the UTRAN by using the terminal. At this time, the RRC connection setup complete message includes the performance information of the terminal. When the terminal successfully transmits the RRC connection establishment message, the terminal establishes an RRC connection with the UTRAN and transitions to the RRC connection state.

Here, the RRC connection request message is transmitted through a random access channel (RACH) and the RRC connection establishment message is transmitted through a forward access channel (FACH). However, the network does not know the existence of the terminal until establishing the RRC connection. Therefore, the UE sends an RRC connection request message, which is the first message, using a RACH commonly used by all UEs. The RACH is transmitted to a connection management terminal of a network through a logical channel commonly used by all terminals called a common control channel (CCCH). Similarly, the first message received by the terminal from the network is also transmitted through a channel that all terminals receive in common. In addition, since the RRC connection establishment message, which is the first message transmitted by the network, includes connection establishment method and channel information applicable only to the UE, the network may deliver the message to the UE only through the common channel until the UE receives the RRC connection establishment message. Can be. At this time, the RRC connection establishment message is transmitted through CCCH, and this message is also transmitted in UM RLC mode.

It is proposed to improve the above-mentioned prior art of the present invention, and an object of the present invention is to propose a faster RRC connection establishment method.

Another object of the present invention is to propose a control information processing method which does not require unnecessary waiting of a mobile terminal.

Summary of the Invention

In order to achieve the above object, the present invention operates in a UM (unacknowledged mode) mode, and is a protocol data unit (protocol) transmitted from a transmitting side a plurality of times by an RLC (Radio Link Control) entity having a receiving window and a timer. Receiving Data Units, but through one common logical channel; Rearranging the received protocol data units using a sequence number of the received protocol data unit, a reception window and a timer; Processing the rearranged protocol data units to reconstruct at least one service data unit; And delivering said at least one service data unit.

In addition, the control information processing method according to the present invention comprises the steps of: transmitting a first control message for controlling the radio resources to the network; Observing a particular channel on which a second control message is received that indicates whether the first control message has been received from the network; And retransmitting the first control message to the network according to the observation result.

In addition, the control information processing method according to the present invention comprises the steps of: determining whether a first control message for controlling radio resources is received from a mobile terminal; According to the determination result, transmitting a second control message indicating whether to receive the first control message to the mobile terminal through a specific channel; And re-receiving the first control message from the mobile terminal according to whether the mobile terminal has received the second control message.

In addition, the control information processing method according to the present invention comprises the steps of: receiving at least one protocol data unit from a lower layer; If restoration of at least one service data unit from the received protocol data unit fails, determining whether a particular area of the at least one service data unit has been successfully received; And transmitting control data including the specific area to a higher layer according to the determination result.

In addition, the control information processing method according to the present invention comprises the steps of: transmitting a control message for controlling the radio resources to the network; Receiving from the network at least one protocol data unit corresponding to the response message to the control message and including an identifier identifying a particular terminal; Determining whether at least one service data unit can be restored from the received at least one protocol data unit; And retransmitting the control message to the network according to the determination result.

In addition, the control information processing method according to the present invention comprises the steps of: receiving a control message for controlling radio resources from a mobile terminal; Including an identifier identifying a particular terminal in at least one protocol data unit corresponding to the response message to the control message; Sending the at least one protocol data unit to the mobile terminal; And re-receiving the control message from the mobile terminal according to whether the mobile terminal has successfully received the at least one protocol data unit.

Invention Example

First embodiment

According to the signal transmission and reception method according to this embodiment, the conventional RRC connection establishment procedure can be improved. As described above, the RRC connection establishment message is transmitted through the CCCH, where the CCCH is used by the UM RLC. In this case, since a physical channel for only a specific terminal is established, messages are transmitted through a common physical channel. That is, the RRC connection setup message is not delivered to the specific physical channel to the terminal to be delivered. Therefore, the probability that the corresponding terminal is properly received is low.

Therefore, even though the UE transmits the RRC connection request message, the network has successfully received it, and the network has properly transmitted the RRC connection establishment message to the UE, the characteristics of the CCCH, which is a common channel, and the characteristics of the UM RLC that do not receive ACK. In many cases, the terminal does not receive properly. At this time, the terminal waits until the T300 timer expires, and if it does not receive the RRC connection establishment message until expiration, it transmits the RRC connection request message again to the network. In the actual UMTS system, since the T300 timer is set to 4 seconds, whenever the UE fails to receive the RRC connection setup message once, a connection delay of 4 seconds occurs. This causes a bad quality to the user.

The signal transmission / reception method according to the present embodiment proposes a method for transmitting a message more reliably and quickly from a network to a terminal. That is, according to the present embodiment, when the network delivers an RRC message to the UE through a common physical channel or a common delivery channel, the RLC entity proposes a method of transmitting one or more times for RLC PDUs generated for one RLC SDU. I would like to.

Specifically, when the UE receives the RRC message through the common physical channel or the common delivery channel, even if the UE receives the same RLC PDU a plurality of times, a method that can correctly recover the RLC SDUs to deliver to the higher end Suggest.

Specifically, the present invention proposes an RLC entity that operates using a reordering timer and a receiving window. That is, the present embodiment proposes a method of using the reception window so that RLC PDUs can be sequentially stored according to SN even when transmitted a plurality of times. In addition, the present invention proposes a method of using the reordering timer in order to prevent an operation delay while waiting for reception of a specific RLC PDU when using a reception window.

Specifically, in the above process, the network proposes to transmit the message through the RLC in the non-response mode.

Preferably in the above process, the network proposes to be RNC. In the above process, it is suggested that the RRC message be mapped to a common logical channel. In the above process, it is suggested that the common logical channel be CCCH.

Preferably, in the above process, the RRC message is proposed to be transmitted through a common transport channel. In the above process, it is suggested that the common logical channel be mapped to the common transport channel. In the above process, it is suggested that the common transport channel be FACH.

In the above process, it is suggested that the common transport channel be mapped to the common physical channel. Preferably, in the above process, the RRC message is proposed to be delivered through a common physical channel. Preferably, in the above process, the common physical channel is S-CCPCH (Secondary Common Control Physical Channel).

More specifically, the present invention proposes that the network transmits the RRC message a plurality of times in order to increase the probability of successful RRC message reception by the UE.

To this end, the present invention proposes an operation method of the RLC entity for the case where the UE receives the same RLC PDU more than once through one common channel. That is, the present embodiment proposes a method of processing the received RLC PDU using the reception window and the reordering timer when the UM RLC receives the same RLC PDU for the same RLC SDU from a single channel a plurality of times.

Preferably, the method for processing the RLC PDU by using the reception window refers to a method of managing by processing the range of SN values of the RLC PDU that can be expected to receive based on the RLC PDU received by the UM RLC.

Preferably, the method for processing the RLC PDU by using the reordering timer, if the UM RLC is left in the receiving window unreserved for reassembly (reassemble) for the received RLC PDU, the re-timer is operated by a certain time After that, it means a method of processing the RLC PDU regardless of whether other PDUs are received.

Preferably, the UM RLC operates when it is determined that the same RLC PDU can be received more than once through the channel when re-ordering is set through a re-ordering indication from a higher level. . In addition, the UM RLC determines that the same RLC PDU can be received at most once for one logical channel when the rearrangement is not set through the rearrangement indicator from the upper end.

Preferably, the terminal proposes to receive information about the rearrangement indicator from the network. The network informs information on whether to perform re-ordering when the UEs receive the RRC messages through system information. The RRC of the terminal informs the RLC how to operate the terminal through the rearrangement indicator based on the information.

In other words, when the network wants to transmit a more reliable RRC message, it informs that the network uses a reordering function when the network sends an RRC message through a channel and a message carrying system information. If the network does not send the RRC message by using the rearrangement function, it is not informed through the system information that the rearrangement function is not used or whether the rearrangement function is used.

After receiving the system information, the terminal uses the rearrangement function if the system information indicates that the rearrangement function is used in the transmission of the RRC message. Specifically, the RLC entity mapped to the channel through which the RRC message is delivered is processed using the rearrangement function. However, when the UE receives system information indicating that the rearrangement function is not used (for example, when the RRC message is instructed to deactivate the rearrangement function or does not provide information on whether to enable the rearrangement function). Do not use the rearrangement function. Specifically, the RLC entity mapped to the channel through which the RRC message is delivered is processed without using the reordering function.

Whether the rearrangement function is activated may be identified according to the release number indicated by the system information. Specifically, when the system information informs that the communication standard is 3GPP release 7 or release 8, the rearrangement function can be activated.

When using the rearrangement function, it is desirable for the network to provide various settings for the reorganization function. The setting value includes the size of the reception window or the timer value of the reordering timer. When the terminal receives the configuration value as the system information, the terminal performs configuration for the RLC entity by using these values.

The above description will be described with reference to FIG. 5.

5 relates to an example of a method of setting a reception window and a reordering timer. Hereinafter, the variables for the reception window and the reordering timer proposed in the present embodiment will be described.

The receiving window corresponds to the range of SN values of the RLC PDUs that the RLC entity receives and processes. The range of the reception window is equal to or greater than a value obtained by subtracting the reception window size from the VR (UDH) to be described below. SN of the RLC PDU included in the reception window is smaller than VR (UDH).

The receiving window size is a value representing the size of the receiving window.

VR (UDR) represents a reception waiting number of a reception window. This value is used when rearrangement is set. This value means the next value of the SN value of the last RLC PDU received sequentially. The initial value of VR (UDR) is determined as follows. If the VR (UDH) to be described below is set due to the first received RLC PDU after the RLC entity is initialized, the value of the VR (UDR) is subtracted from the VR (UDH) value by subtracting the reception window size value. It is set as an initial value.

VR (UDH) represents the maximum reception number of the reception window. This value is used when rearrangement is set. This value means the upper limit of the reception window in the UM RLC. In addition, this value means the next value of the largest value among the SN values of the received RLC PDU. If an RLC PDU with SN (= x) outside the range of the previously set reception window is received, VR (UDH) is determined as follows. If an RLC PDU equal to x is received, VR (UDH) is set to x plus 1. The initial value of VR (UDH) is set to the SN of the first received RLC PDU after the RLC entity is initialized.

VR (UDT) represents a timer instruction number. This value is used only when reordering is set. This value is set to the SN value corresponding to the RLC PDU to which the reordering timer is set. The initial value is 0.

According to this embodiment, the UM RLC receives a new RLC PDU from a lower layer. In addition, depending on whether or not rearrangement is activated, if the rearrangement is not set, the operation is performed as in the prior art, and if the rearrangement is set, the operation is performed according to the SN value of the received RLC PDU, the reception window, and the rearrangement timer (S1).

In the above process, the UM RLC operates as in the prior art, wherein VR (US) is updated according to the SN value of the received RLC PDU, and if the update width of VR (US) is not 1, it is determined that there is a lost PDU. Deleting the RLC SDUs related to the RLC PDUs that are determined to be lost, and recovering only the RLC SDUs that are determined to be successfully received, and transmits them to the upper layer. If the update width of the VR (US) is 1 in the above process, it is determined that there is no lost PDU, and the RLC SDUs are recovered and transmitted to the upper layer based on the received RLC PDUs. An RLC SDU associated with a particular RLC PDU represents the RLC SDU when some data of the RLC SDU or LI (length indicator) indicating the end of the RLC SDU is included in the particular RLC PDU.

The above-described 'UM RLC operates according to the SN of the RLC PDU, the reception window, and the reordering timer (S1)' means the following. That is, the UM RLC inspects the newly received RLC PDU using the SN value of the RLC PDU, the reception window, and the reception standby number (VR (UDR)), and processes the corresponding RLC PDU according to the inspection result (S2). According to the presence or absence of the RLC PDU whose SN value is VR (UDR), the RLC PDU is additionally processed (S3), after which the reordering timer is additionally processed (S4), and further processed for the RLC PDU for which reconfiguration is reserved ( S5).

In the above process, 'SNC using the SN value of the RLC PDU, the reception window and the reception standby number (VR (UDR)) is examined, and the corresponding RLC PDU is processed according to the inspection result (S2). First, the UM RLC checks whether the SN value of the received RLC PDU is located in the reception window. If the SN value of the PDU is located in the reception window, if the SN value is smaller than VR (UDR) or if an RLC PDU corresponding to the SN value is previously received, the corresponding RLC PDU is deleted. Place the RLC PDU in the receive buffer indicated by the SN value of the RLC PDU. If the SN value of the received RLC PDU is not located in the reception window, the received RLC PDU is placed in the location indicated by the SN value of the RLC PDU, and the VR (UDH) value is set as the SN value of the RLC PDU. Update the position of. Then, among the PDUs stored in the reception buffer provided in the terminal, SN is RLC PDUs outside the range of the updated reception window (that is, SN is VR (UDH) from the lower limit of the reception window size minus VR (UDH). RLC PDUs that do not exist between the upper bounds of) are reserved for reconstruction.If VR (UDR) is smaller than the updated receive window, VR (UDR) is subtracted from VR (UDH) minus the receive window size. Update

In the above process, 'processing the RLC PDU according to the presence or absence of an RLC PDU whose SN value is VR (UDR) (S3)' means that when an RLC PDU having a specific SN value exists in a reception window, the RLC PDU is present. Up to the first RLC PDU not sequentially received for reconfiguration, and update the VR (UDR) value to the SN value of the first RLC PDU not sequentially received.

In the process, 'processing the refining timer (S4).' First, if there is a reordering timer in operation, the UM RLC checks whether the RLC PDU whose SN value is VR (UDT) is reserved for reconstruction and checks. If it is reserved for reconstruction, it means stopping the reorder timer. The UM RLC then checks again if there is a reordering timer in operation, and if there is no reordering timer in operation, checks if there are RLC PDUs present in the receive buffer and not scheduled for reconfiguration, If there are unreserved RLC PDUs, the reordering timer is restarted for the RLC PDU corresponding to the highest SN value among the PDUs, and the VR (UDT) is updated with the SN value of the RLC PDU.

In the above process, 'processing for the reconfigured reserved RLC PDU' (S5) means that for RLC PDUs for which reconfiguration is reserved, if there are RLC PDUs that are not received first, RLC SDUs related to the RLC PDUs not received. Deleting them, and then restoring (ie, reconfiguring) the RLC SDUs based on the received RLC PDUs, and delivering them to the upper layer. Here, the RLC SDU associated with a specific RLC PDU means an RLC SDU at this time when some data of the RLC SDU or LI (length indicator) indicating the end of the RLC SDU is included in the specific RLC PDU.

In addition, when the reordering timer expires at any time in the above processes, the RLC PDUs reserved for reconfiguration of RLC PDUs having a VR (UDT) value or less are reserved, and the RLC PDUs having a SN value of VR (UDT) to the first RLC PDU not sequentially received. Reserve for reconstruction and update VR (UDR) with the SN value of the first RLC PDU not received sequentially. As a result of performing the above process, if there are RLC PDUs present in the reception buffer and for which reconfiguration is not reserved, the re-timer is restarted for the RLC PDU corresponding to the highest SN value among the PDUs, and the SN of the RLC PDU is restarted. Update VR (UDT) with the value. When the PDU of the SN corresponding to the VR (UDT) is removed from the reception buffer, the reordering timer is stopped. When the RLC PDU is accumulated in the receiving buffer by the reordering function, the reordering timer is started if the reordering timer does not operate, and VR (UDT) is designated as the SN value of the PDU.

5 is a specific example of implementing the above-described rearrangement operation through the above-described variables. Hereinafter, each step shown in FIG. 5 will be described in detail.

An RLC PDU whose SN value is RSN is received from the lower stage of the UM RLC (S501).

If the rearrangement is set, the process is performed from step S505. If the rearrangement is not set, the process is performed from step S503.

The VR (US) is updated, and if the update width of the VR (US) is not 1, the SDUs related to the PDUs determined to be lost are deleted (S503). In this case, the RLC PDUs determined to be lost refer to RLC PDUs that are greater than or equal to VR (US) before the serial number is updated and smaller than RSN.

The process ends after the RLC SDU is restored using the received RLC PDU and transferred to the upper layer (S504).

If the RSN is not included in the region of the receiving window, the process is performed from S507. If the RSN is included in the region of the receiving window, the process is performed from S506.

If the RSN is smaller than VR (UDR) or the received RLC PDU is a previously received PDU, then the corresponding RLC PDU is deleted, otherwise the corresponding RLC PDU is placed in the receiving buffer where the RSN indicates. After that, the process is performed from step 10 (S506).

The received RLC PDU is placed at the location indicated by the RSN, and the VR (UDH) is updated to a value obtained by adding 1 to the RSN (S507).

RLC PDUs having a smaller SN value than the updated reception window, that is, located outside the reception window, are reserved for reconfiguration (S508).

If the VR (UDR) is positioned below the updated reception window, the VR (UDR) is updated to a value obtained by subtracting the reception window size from the VR (UDH) (S509).

If the RLC PDU corresponding to the VR (UDR) is not stored in the reception buffer, the process is performed from step S512. Otherwise, the process is performed from the following process (S510).

In the reception buffer, the RLC PDUs from the RLC PDU corresponding to the VR (UDR) to the first RLC PDU not sequentially received are reserved for reconfiguration (S511). Thereafter, the VR (UDR) is updated with the SN value of the first RLC PDU not sequentially received.

If the reordering timer is not operating, the process is performed from step S514, otherwise, the process is performed from step S513 (S512).

If the RLC PDU corresponding to the VR (UDT) is reserved for reconfiguration, the reordering timer is stopped (S513).

If the reordering timer is in operation, the process is performed from S517. Otherwise, the process is performed from the following process (S514).

If there are RLC PDUs stored in the reception buffer and not reserved for reconfiguration, the process is performed from step S516, otherwise, the process starts from step S517 (S515).

A reordering timer is driven for the RLC PDU having the largest SN value among the RLC PDUs not reserved for reconfiguration in the reception buffer, and the VR (UDT) is set to the SN value of the PDU (S516).

For RLC PDUs for which reordering is reserved, RLC SDUs related to RLC PDUs determined to be lost are deleted, and for received RLC PDUs, the RLC SDUs are restored, transferred to the higher level, and the process ends. (S517).

The above operation is summarized as follows. As described above, the reception window is used as a means for processing a duplicate RUM PDU received. More specifically, a UM RLC PDU that is duplicated received is processed using a VR (UDR) indicating a position of an in-sequence RLC PDU, a VR (UDH) indicating an upper limit of a reception window, and a window size. . Using the reception window, if there is an RLC PDU received for the first time, the RLC PDU is stored and the area of the reception window is updated, and if there are duplicated or already sequentially received RLC PDUs, it is deleted. The reception window is updated with an upper limit and a lower limit to manage RLC PDUs that are not sequentially received.

Using the reception window, there is an advantage that the specific RLC PDUs are sequentially stored even if a plurality of RLC PDUs are received multiple times or the order is not sequential. However, in this case, since it is possible to wait for an unreceivable RLC PDU without limitation, the RLC PDUs and their associated RLC SDUs are also deleted using the reordering timer. More specifically, according to the operation of the reordering timer, RLC PDUs having SNs of VT (UDT) or less are regarded as unreceivable RLC PDUs and deleted.

In the above process, the operation of the network should consider not only the terminal supporting the rearrangement function but also the terminal not supporting the rearrangement function. Terminals that do not support the reordering function refer to terminals that perform operations of the existing UM RLC. These terminals always want the SN of the received RLC PDU to increase by 1, and if the increase of SN exceeds 1, it is assumed that the loss of the RLC PDU occurs. Therefore, if the network supports the reordering function, if the transmission order of the RLC PDUs for one RLC SDU is changed arbitrarily, the terminal that does not support the reordering function may not be properly received.

Accordingly, an embodiment of the present invention is to propose a method in which an RLC entity of a network using a rearrangement function can correctly transmit RRC messages to a terminal that does not support the rearrangement function.

Specifically, the present invention proposes that RLC PDUs for one RLC SDU are transmitted sequentially. For example, when the PDU constituting the RLC SDU 1 is RLC PDU 1, RLC PDU 2, RLC PDU 3, the RLC PDU is always transmitted to the terminal in the order of RLC PDU 1, RLC PDU 2, RLC PDU 3, one Even if the RLC PDU is transmitted more than once, it is proposed to transmit in the order of RLC PDU 1-> RLC PDU 2-> RLC PDU 3-> RLC PDU 1-> RLC PDU 2-> RLC PDU 3.

In another method, when the network transmits a message to the UE, when the RLC PDU is transmitted a plurality of times, the network proposes that one RLC PDU is continuously transmitted as many times as the number of retransmissions. For example, if an RLC SDU consists of RLC PDU 1, RLC PDU 2, RLC PDU 3, and one RLC PDU is sent twice, then RLC PDU 1-> RLC PDU 1-> RLC PDU 2- It is proposed to transmit in the manner of> RLC PDU 2-> RLC PDU 3-> RLC PDU 3.

In addition, when transmitting consecutive RRC messages, when one targets a terminal that supports reordering and the other targets a terminal that does not support reordering, the parts of two messages are not included in one RLC PDU. Suggest to say. That is, it is proposed not to include portions of two or more RLC SDUs in one RLC PDU.

It is also suggested to use the rearrangement function selectively. Specifically, the network proposes to use a function of transmitting a single RLC PDU multiple times only to a terminal supporting the rearrangement function based on release information of the terminal or information on whether the rearrangement function of the terminal is supported. To this end, the terminal proposes to inform the network whether to support its reordering function when connecting to the RRC.

Second embodiment

This embodiment proposes a method of preventing a terminal from waiting for a response from the network more than necessary. That is, if the RRC message sent by the terminal is not received in the network, it is meaningless for the terminal to wait for a response from the network. For example, after the terminal sends an RRC connection request message, the terminal waits for a response from the network. If there is no response until the retransmission timer expires, then the terminal sends an RRC connection request message again. At this time, if the RRC connection request message transmitted by the terminal does not arrive properly in the network, it is meaningless for the terminal to wait for a response from the network. Therefore, it is preferable that the terminal retransmits an RRC message such as an RRC connection request message immediately after recognizing that the message transmitted by the UE does not arrive properly in the network.

To this end, in the present invention, when the terminal sends an RRC message through an uplink common channel, if there is no response that the message is properly received from the network within a predetermined time, the terminal transmits the RRC message again.

Preferably in the above process, the network proposes to be RNC. In the above process, it is suggested that the RRC message be mapped to a common logical channel. Preferably, in the above process, the common logical channel is proposed to be a common control channel (CCCH).

Preferably, in the above process, the RRC message is proposed to be transmitted through a common transport channel. In the above process, it is suggested that the common logical channel be mapped to the common transport channel. Preferably, the common transport channel in the above process is proposed to be a random access channel (RACH).

In the above process, it is suggested that the common transport channel be mapped to the common physical channel. Preferably, the RRC message is transmitted through a common physical channel in the above process. Preferably, the common physical channel in the above process is referred to as a PRACH (Physical Random Access Channel).

In the above process, when the network receives an RRC message from the terminal, the network immediately gives a response thereto. There are many ways to do this.

In a first example of giving a response immediately, the network sends an acknowledgment to the terminal upon receipt of a message from the terminal through the channels. For example, upon receiving the RRC connection request message, the network notifies the terminal that it has received the RRC connection request message. The terminal receiving this waits until it receives a response message for the RRC message sent from the network. For example, if the terminal transmits the RRC connection request message, the terminal waits for an RRC connection setup message after receiving the acknowledgment.

In the process, the terminal retransmits the RRC message immediately if it does not receive an acknowledgment from the network within a predetermined time after transmitting the RRC message to the channel.

Note that the acknowledgment information means information on whether the network has successfully received the RRC message sent by the UE. For example, the conventional RRC connection establishment message is distinguished from the acknowledgment information because the RRC connection establishment message is a message for RRC connection, not a message indicating whether the response message to the RRC connection request message has been successfully received.

Preferably, the acknowledgment message that the network sends to the terminal in the above process is an RRC message. Or, the network proposes to use a special physical channel to send an acknowledgment for the RRC message sent by the terminal. In the current transmission through the RACH, the PREamble portion receives an acknowledgment through a channel called an Acquisition Indication Channel (AICH). Accordingly, only a response to the message part transmitted by the terminal may be transmitted to the terminal through a channel physically specialized for the specific terminal. That is, the acknowledgment may be performed through a physical channel only for a specific terminal. For example, upon receiving the RRC connection request message, the network notifies the UE of the RRC connection request message using the physical channel. The terminal receiving this waits until it receives a response message for the RRC message sent from the network. For example, if the terminal transmits an RRC connection request message, the terminal waits for an RRC connection establishment message after receiving the acknowledgment.

In the above process, if the terminal does not receive an acknowledgment through the physical channel from the network within a predetermined time after transmitting the RRC message to the channel, the terminal immediately retransmits the RRC message.

In the above process, the physical channel for which the terminal performs acknowledgment is transmitted to the terminal through a downlink physical channel after a certain time after the terminal transmits an RRC message or after the terminal performs data transmission through an uplink physical channel. do. It is also possible to simply transmit a bit of information to the terminal.

As a second example of immediately giving a response, the network receiving the RRC message from the terminal informs the terminal of the time it is expected to send a response. In the real world, if you have a lot of load, you'll have to start with the highest priority. If a terminal sends an RRC connection request message and the network receives it properly, if a lot of high priority tasks are pushed, the terminal may exceed the maximum time T300 for waiting for a response message. Therefore, in this case, if the terminal sends the RRC connection request message again, this will only cause excess network workload. Therefore, in this case, it would be helpful if the network informed the terminal when it could send a response. In addition, the terminal receives the message, waits for that time, and waits for the RRC response message for the time indicated by the network even if the t300 timer expires in the meantime. If no response RRC message is received from the network even after that time, the terminal transmits a new message or performs another process.

Third embodiment

In order to achieve the object of the present invention, the third embodiment proposes a method of operating a new RLC entity and a format of a new RLC message.

The operation method of the new RLC entity is described below.

In fact, the RLC entity performs an operation of delivering the RLC SDU received from the upper layer or combines the RLC PDUs received from the lower layer to restore the RLC SDU and deliver the RLC SDU to the upper layer. Thus, the RLC entity operates regardless of the content of the data it transmits. The format of the defined RLC SDU does not indicate what is the target of the RLC SDU.

In particular, when the RLC entity is mapped to a channel commonly used by several terminals, the RLC entity delivers all messages received and successfully decoded to the upper end. And discards the partially received RLC SDU. However, most RRC messages, for example, an RRC message transmitted through a common channel tells which terminal a particular part of the message is intended for (eg, the first part). That is, even if an RLC SDU is split into several parts, if only the first part is properly received, the receiver may know who the RRC message is intended for.

In particular, the RLC entity may use several LIs to know whether the fragment of the RLC SDU included in the received RLC PDU is the first part of the RLC SDU. In addition, each RLC PDU may be verified whether there is an error in the physical layer. Thus, for an RLC PDU received by a RLC entity on a common channel, the RLC PDU contains the first part of a certain RLC SDU, even though it may not receive all the RLC PDUs associated with that RLC PDU. If the PDUs do not have a CRC error, the RLC entity extracts the maximum part of the RLC SDUs that can be continuously extracted from the first part of the RLC SDU using the consecutive RLC PDUs from the RLC PDU, and delivers them to the RRC stage. It also suggests that it is an incomplete RLC SDU.

The RRC entity receiving the RRC entity interprets the first part by using a part of the RRC message and checks whether its identifier is included. Thus, if its identifier is included, it recognizes that the RRC message sent to it has failed to transmit, and determines that it cannot receive the response it was waiting for. And immediately re-run the RRC process you were trying to try. For example, if the UE was waiting for an RRC connection establishment message and delivered a partial RRC message including the first part with an indicator that the RLC entity was not completely received, the RRC entity may have its own RRC message partially received from the RLC. Check if an identifier is included. If the check indicates that the identifier is its own, it determines that it has failed to receive the RRC connection establishment message, and suggests to immediately start transmitting the RRC connection request message again.

Of course, if the RRC connection request message has already been transmitted in excess of the maximum number of RRC connection request messages allowed in this process, the RRC stops all operations and informs the upper level.

In the above process, the identifier thereof refers to an International Mobile Station Identity (IMSI), a Packet Temporary Mobile Subscriber Identity (P-TMSI), a Temporary Mobile Subscriber Identity (TMIS), or the like, which is an identifier used by an RNTI or higher level.

In summary, through the above-described operation, the RLC entity according to the present embodiment does not delete the SDU and the PDUs corresponding to the SDU, unlike the conventional case, even if the successful restoration of the SDU is impossible. In other words, if the first part of the SDU is properly received, the receiver of the message can be identified. Therefore, if there is no error for the RLC PDUs including the first part of the specific RLC SDU, the part of the RLC SDU that can be recovered to the upper level is higher. send.

Hereinafter, the format of the new RLC message proposed in this embodiment will be described.

According to the present embodiment, the MAC layer may send a response to the terminal using the upper identifier of the terminal. Alternatively, the identifier of the terminal may be added by extending the header portion of the RLC PDU. That is, when a network sends an RRC message through the channel, that is, an RLC entity to which an RRC message is mapped, the network transmits an identifier in an RLC PDU. When the UE side receives at least one RLC PDU corresponding to the RRC message, the UE may recognize that the network has responded to the RRC message sent by the UE. In this case, when the UE cannot completely restore the RLC SDU connected to the RLC PDU, the UE may perform an RRC process again and send an RRC message to the network. Through this, fast RRC message transmission and reception is possible. Preferably, the RRC process is a process of transmitting an RRC connection establishment message. Preferably, in the above process, the message sent to the terminal by the network may be a cell update confirmation (CELL UPDATE CONFIRM) message instead of the message for the RRC process. That is, when the conventional A cell performs communication with the B cell as the terminal moves, the cell update procedure for the B cell is performed. In the cell update procedure, a cell update confirmation message is transmitted. In this case, information for identifying a terminal may be included in a cell update confirmation message.

It is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

The present invention has the following effects.

First, the present invention has the advantage that the mobile terminal performs the RRC connection procedure without unnecessary waiting. In addition, according to the control information processing method of the present invention can perform a cell update procedure more quickly.

Claims (31)

Receives protocol data units transmitted from the transmitting side multiple times by a Radio Link Control (RLC) entity operating in UM (Unacknowledgede mode) mode and having a reception window and a timer, but having one common logic. Receiving over a channel; Rearranging the received protocol data units using a sequence number of the received protocol data unit, a reception window and a timer; Processing the rearranged protocol data units to reconstruct at least one service data unit; And Delivering the at least one service data unit Method of processing control information in a mobile communication system comprising a. The method of claim 1, Determining whether to perform the rearrangement according to indication information received from a higher layer Method for processing control information in a mobile communication system further comprising. The method of claim 1, Using the receive window is to manage the range of the serial number of the protocol data units that it expects to receive based on the received protocol data units. Method for processing control information in a mobile communication system, characterized in that. The method of claim 1, Wherein the receive window is used for temporarily storing protocol data units in a buffer, wherein the temporary storage is for receiving and rearranging such that the non-sequential protocol data units are delivered sequentially. Method for processing control information in a mobile communication system, characterized in that. The method of claim 1, The receiving window is updated after processing the rearranged protocol data units Method for processing control information in a mobile communication system, characterized in that. The method of claim 1, Using the timer is to operate a reorder timer for received protocol data units that are not reserved for reconfiguration and are present in the receive window, Received protocol data units that are not reserved for the reconfiguration and present in the receive window are processed after a certain time has elapsed, regardless of whether other protocol data units have been received. A method for processing control information in a mobile communication system, characterized by the above-mentioned. The method of claim 1, The timer is used to limit the time period for receiving and temporarily storing protocol data units for reordering. A method for processing control information in a mobile communication system, characterized by the above-mentioned. The method of claim 1, If the serial number of the newly received protocol data unit is the serial number of the already received protocol data unit, removing the newly received protocol data unit Method for processing control information in a mobile communication system further comprising. The method of claim 1, The protocol data unit transmitted a plurality of times corresponds to a radio resource control (RRC) connection establishment message. Method for processing control information in a mobile communication system, characterized in that. The method of claim 1, The common logical channel is CCCH (Common Control Channel) Method for processing control information in a mobile communication system, characterized in that. Transmitting a first control message for controlling a radio resource to a network; Observing a particular channel on which a second control message is received that indicates whether the first control message has been received from the network; And Retransmitting the first control message to the network according to the observation result Method of transmitting control information in a mobile communication system comprising a. The method of claim 11, The specific channel is any one of a specific physical channel and a logical channel Method of transmitting control information in a mobile communication system, characterized in that. The method of claim 11, The retransmitting may be performed when the second control message has not been received from the network for a certain time. Method of transmitting control information in a mobile communication system, characterized in that. The method of claim 11, The first control message is an RRC connection request message Method of transmitting control information in a mobile communication system, characterized in that. Determining whether a first control message for controlling radio resources is received from a mobile terminal; According to the determination result, transmitting a second control message indicating whether to receive the first control message to the mobile terminal through a specific channel; And Re-receiving the first control message from the mobile terminal according to whether the mobile terminal has received the second control message Method of receiving control information in a mobile communication system comprising a. The method of claim 15, The specific channel is any one of a specific physical channel and a logical channel Method of receiving control information in a mobile communication system, characterized in that. The method of claim 15, The first control message is an RRC connection request message. Method of receiving control information in a mobile communication system, characterized in that. Receiving at least one protocol data unit from a lower layer; If restoration of at least one service data unit from the received protocol data unit fails, determining whether a particular area of the at least one service data unit has been successfully received; Transmitting control data including the specific area to a higher layer according to the determination result. Method of processing control information in a mobile communication system comprising a. 19. The method of claim 18, wherein transferring the control data comprises: To be performed when the particular area is successfully received Method for processing control information in a mobile communication system, characterized in that. The method of claim 18, The particular area comprises a starting point of the at least one service data unit Method for processing control information in a mobile communication system, characterized in that. The method of claim 18, The control data delivered to the higher layer, Including areas continuously received without error from said particular area Method for processing control information in a mobile communication system, characterized in that. The method of claim 18, Wherein said at least one protocol data unit corresponds to an RRC connection establishment message. Transmitting a control message for controlling a radio resource to a network; Receiving from the network at least one protocol data unit corresponding to the response message to the control message and including an identifier identifying a particular terminal; Determining whether at least one service data unit can be restored from the received at least one protocol data unit; And Retransmitting the control message to the network according to the determination result Method of transmitting control information in a mobile communication system comprising a. The method of claim 23, wherein Determining whether the received at least one protocol data unit is for itself using the identifier Method for transmitting control information in the mobile communication system further comprising. The method of claim 23, wherein And the identifier is included in a header of the at least one protocol data unit. The method of claim 23, wherein The response message is an RRC connection establishment message, characterized in that for transmitting the control information in the mobile communication system. The method of claim 23, wherein The response message is a cell update confirmation message, characterized in that for transmitting the control information in the mobile communication system. Receiving a control message from a mobile terminal for controlling radio resources; Including an identifier identifying a particular terminal in at least one protocol data unit corresponding to the response message to the control message; Sending the at least one protocol data unit to the mobile terminal; And Re-receiving the control message from the mobile terminal according to whether the mobile terminal has successfully received the at least one protocol data unit Method of receiving control information in a mobile communication system comprising a. The method of claim 28, And the identifier is included in a header of the at least one protocol data unit. The method of claim 28, The response message is an RRC connection establishment message, characterized in that for receiving the control information in the mobile communication system. The method of claim 28, The response message is a cell update confirmation message, characterized in that for receiving control information in a mobile communication system.

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