KR20170019886A

KR20170019886A - The Apparatus and Method for canceling of RACH transmission in a wireless communication system

Info

Publication number: KR20170019886A
Application number: KR1020150114357A
Authority: KR
Inventors: 이정구
Original assignee: 엘지전자 주식회사
Priority date: 2015-08-13
Filing date: 2015-08-13
Publication date: 2017-02-22

Abstract

The present specification relates to a method for a terminal to cancel a Random Access Channel (RACH) transmission procedure in a wireless communication system. At this time, a first RACH transmission procedure is started to transmit a first message in a first TTI (Transmission Time Interval), a second TTI for retransmission of a first message Initiating a second RACH transmission procedure at the current TTI and using the Persistence test to determine if a Physical RACH is available at the current TTI. At this time, if the physical RACH is unavailable in the current TTI based on the Persistence test, the second RACH transmission procedure can be canceled if retransmission for the first message is not necessary.

Description

[0001] The present invention relates to a method and apparatus for canceling a RACH transmission procedure in a wireless communication system,

BACKGROUND 1. Technical Field The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for canceling a Random Access Channel (RACH) transmission procedure in a wireless communication system.

As a wireless communication system, the present invention can be applied to a Universal Mobile Telecommunications System (UMTS). The details of the technical specification of UMTS are disclosed in "3rd Generation Partnership Project (Technical Specification Group Radio Access Network)" .

Referring to FIG. 1, a UMTS includes a User Equipment (UE), a UMTS Terrestrial Radio Access Network (UTRAN), and a Core Network (CN). UTRAN is composed of one or more radio network subsystems (RNS), and each RNS includes one radio network controller (RNC) and one or more base stations (Node B) managed by the RNC . One base station may have more than one cell.

Also, the present invention can be applied to Enhanced-Universal Mobile Telecommunications System (E-UMTS). At this time, the E-UMTS is also called an LTE (Long Term Evolution) system. It can also be applied to other communication systems as well. Hereinafter, the configuration of the present invention will be described based on UMTS, but the present invention is not limited to UMTS.

The present specification has an object to provide a method and apparatus for canceling a RACH transmission procedure in a wireless communication system.

The present specification has an object to provide a method for detecting a new RACH transmission procedure unnecessary in a wireless communication system, thereby preventing a new uplink data transmission efficiency.

The present disclosure relates to a method for improving transmission efficiency by allowing a terminal to transmit a new message by terminating a RACH transmission procedure upon receiving a response message for a previously transmitted message while performing a RACH transmission procedure for message retransmission And to provide them.

A method for canceling a Random Access Channel (RACH) transmission procedure in a wireless communication system according to an embodiment of the present invention includes: initiating a first RACH transmission procedure to transmit a first message in a first TTI (Transmission Time Interval) The method comprising: initiating a second RACH transmission procedure in a second TTI for retransmission of a first message if a response message for the first message is not received; and transmitting a physical RACH in a current TTI using Persistence test And confirming whether it is available or not. At this time, if the physical RACH is unavailable in the current TTI based on the Persistence test, the second RACH transmission procedure can be canceled if retransmission for the first message is not necessary.

In addition, according to an embodiment of the present invention, a terminal apparatus for canceling a Random Access Channel (RACH) transmission procedure in a wireless communication system may be included. The terminal device may include a receiving module for receiving a message from an external device, a transmitting module for transmitting a message to an external device, and a processor for controlling the receiving module and the transmitting module. At this time, the processor starts the first RACH transmission procedure using the transmission module and transmits the first message in the first TTI (Transmission Time Interval), and does not receive the response message for the first message using the reception module , It is possible to start the second RACH transmission procedure in the second TTI for retransmission of the first message using the transmission module and to check whether the physical RACH can be used in the current TTI by using Persistence test. At this time, if the physical RACH is unavailable in the current TTI based on the Persistence test, the second RACH transmission procedure can be canceled if retransmission for the first message is not necessary.

In addition, the method for canceling the RACH transmission procedure in the wireless communication system and the following matters regarding the terminal apparatus can be applied in common.

According to one embodiment of the present disclosure, the second RACH transmission procedure can be canceled only when it is the first transmission attempt for the first message.

Also, according to an embodiment of the present invention, if the physical RACH is not available in the current TTI based on the Persistence test, if retransmission of the first message is required, Persistence test is performed in the third TTI, which is the next TTI of the current TTI Whether physical RACH can be used or not.

Also, according to one embodiment of the present disclosure, the first message may be a message set based on a Radio Link Control (PDC) Protocol Data Unit (PDU).

According to an embodiment of the present invention, when the RLC layer does not receive the response message for the first message, the RLC layer stores the first message in the RLC buffer, and upon receiving the response message, Messages can be deleted.

Also, according to an embodiment of the present invention, when the first message is deleted from the RLC buffer, retransmission of the first message may not be necessary.

Also, according to one embodiment of the present disclosure, the response message may be a status report.

The present specification can provide a method and apparatus for canceling a RACH transmission procedure in a wireless communication system.

The present specification can provide a method for improving new uplink data transmission efficiency by detecting and preventing an unnecessary RACH transmission procedure in a wireless communication system.

The present disclosure relates to a method for improving transmission efficiency by allowing a terminal to transmit a new message by terminating a RACH transmission procedure upon receiving a response message for a previously transmitted message while performing a RACH transmission procedure for message retransmission .

The effects obtainable in the present specification are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a diagram conceptually illustrating a network structure of a UMTS according to an embodiment of the present invention.
2 is a diagram showing a structure of a wireless protocol used in UMTS.
3 is a diagram illustrating a message transmission delay process that may occur during a RACH transmission procedure.
4 is a diagram illustrating a method of performing a RACH transmission procedure based on the presence or absence of a transmission message.
5 is a diagram illustrating a method of canceling a RACH transmission procedure between a UE and a UTRAN.
6 is a flowchart illustrating a method of canceling a RACH transmission procedure according to an embodiment of the present invention.
7 is a block diagram of a terminal device according to an embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

The specific terminology used in the following description is provided to aid understanding of the present invention, and the use of such specific terminology may be changed into other forms without departing from the technical idea of the present invention.

In some instances, well-known structures and devices are omitted or shown in block diagram form around the core functions of each structure and device in order to avoid obscuring the concepts of the present invention. In the following description, the same components are denoted by the same reference numerals throughout the specification.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of IEEE 802 systems, 3GPP systems, 3GPP LTE and LTE-Advanced (LTE-Advanced) systems and 3GPP2 systems, which are wireless access systems. That is, the steps or portions of the embodiments of the present invention that are not described in order to clearly illustrate the technical idea of the present invention can be supported by the documents. In addition, all terms disclosed in this document may be described by the standard document.

The following description will be made on the assumption that the present invention is applicable to a CDMA system such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access And can be used in various radio access systems. CDMA may be implemented in radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented in a wireless technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA).

Furthermore, the terms first and / or second, etc. may be used herein to describe various components, but the components should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example, without departing from the scope of the rights under the concept of the present disclosure, the first element being referred to as the second element, , The second component may also be referred to as a first component.

Also, throughout the specification, when an element is referred to as " including " an element, it means that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. And the description "... unit", "… Quot; and " part " refer to a unit for processing at least one function or operation, which may be implemented as a combination of hardware and / or software.

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

The radio protocol layers exist in pairs in the UE and the UTRAN, and are responsible for data transmission in the radio section. To describe each of the wireless protocol layers, the PHY layer (or physical layer) as the first layer transmits data to the wireless section using various wireless transmission techniques. The PHY layer is responsible for reliable data transmission over the wireless section. The PHY layer and the MAC layer, which is an upper layer, are connected through a transport channel. The transport channel is classified into a dedicated (Dedicated) transport channel and a common transport channel depending on whether the channel is shared.

In the second layer, MAC (Medium Access Control), RLC (Radio Link Control), PDCP (Packet Data Convergence Protocol), and BMC (Broadcast / Multicast Control) layers exist. First, the MAC layer maps various logical channels to various transport channels, and also performs logical channel multiplexing in which a plurality of logical channels are mapped to one transport channel. The MAC layer is connected to an RLC layer, which is an upper layer, through a logical channel. A logical channel includes a control channel for transmitting control plane information according to the type of information to be transmitted, And a traffic channel for transmitting information of a user plane (User Plane).

The MAC layer includes a MAC-b sublayer, a MAC-d sublayer, a MAC-c / sh sublayer, a MAC-hs / ehs sublayer, and a MAC- Or a MAC-i / is sublayer. The MAC-c sublayer controls the BCH (Broadcast Channel), which is a transport channel responsible for broadcasting system information. The MAC-c / sub sublayer controls the Forward Access Channel (FACH) ), And the MAC-d sublayer manages a dedicated channel (DCH) or a dedicated E-DCH (Enhanced Dedicated Channel), which is a dedicated transport channel for a specific UE. The MAC-hs / ehs sub-layer manages HS-DSCH (High Speed Downlink Shared Channel), which is a transmission channel for high-speed downlink data transmission, in order to support high-speed data transmission in both downward and upward directions. The MAC / is sub layer manages an Enhanced Dedicated Channel (E-DCH), which is a transmission channel for high-speed uplink data transmission.

The RLC layer is responsible for guaranteeing the QoS of each radio bearer (RB) and transmitting the data accordingly. The RLC has one or two independent RLC Entities for each RB in order to guarantee the QoS inherent to the RB. In order to support various QoS, the RLC has a Transparent Mode (UM), an Unacknowledged Mode (UM) And AM (Acknowledged Mode). The RLC also plays a role of adjusting the size of the data so that the lower layer is suitable for transmitting data to the wireless section. For this, the RLC also performs a function of splitting and connecting the data received from the upper layer.

The PDCP layer is located at the top of the RLC layer and enables data to be transmitted using IP packets such as IPv4 or IPv6 to be efficiently transmitted in a wireless section having a relatively small bandwidth. To this end, the PDCP layer performs a header compression function, which transmits only necessary information in the header portion of the data, thereby increasing the transmission efficiency of the radio section. The PDCP layer exists mainly in the PS domain because header compression is a basic function, and there is one PDCP entity per RB in order to provide an effective header compression function for each PS service. Also, if the PDCP layer exists in the CS domain, the header compression function is not provided.

In addition, a BMC (Broadcast / Multicast Control) layer exists in the upper layer of the RLC layer in the second layer, and performs a function of scheduling a cell broadcast message and broadcasting it to terminals located in a specific cell.

An RRC (Radio Resource Control) layer located at the bottom of the third layer is defined only in the control plane, and controls parameters of the first and second layers in association with the setting, resetting, and releasing of RBs, Channels, transmission channels, and physical channels. In this case, the RB means a logical path provided by the first and second layers of the wireless protocol for data transmission between the terminal and the UTRAN. Generally, the RB is set to a wireless protocol necessary for providing a specific service Layer, and channel, and setting specific parameters and operating methods for each layer.

The Non-Access Stratum (NAS) layer located at the top of the third layer is largely divided into an MM (Mobility Management) entity and a CM (Connection Management) entity. The MM entity distinguishes each terminal and manages a plurality of terminals by a TMSI (Temporary Mobile Subscriber Identity) reassignment process, an authentication process, a terminal identification process, and an IMSI (International Mobile Subscriber Identity) attaching process. Also, the MM entity manages the location information of the current terminal through the update of the location information. The CM entities provide and control the services provided by the network. Accordingly, the corresponding CM entities can establish, manage, and terminate a voice call, provide a session connection setup, management, termination, and SMS (Short Message Serving) corresponding to data communication, .

Both RRC and NAS messages are transmitted through a logical path called SRB (Signaling Radio Bearer). SRB # 0 is used to transmit all RRC messages transmitted over the CCCH logical channel. SRB # 1, # 2, # 3, and # 4 are all used to transmit all RRC or NAS messages transmitted over the DCCH logical channel. SRBs # 1 and # 2 transmit an RRC message, and SRBs # 3 and # 4 transmit a NAS message.

Hereinafter, as a specific embodiment of the present invention, a method of canceling a RACH transmission procedure when messages or data are exchanged between a UE and a UTRAN will be described in detail. At this time, although the present invention is described based on the contents disclosed in 25.321 and 25.322 as a standard document, the present invention is also applicable to other wireless communication systems, and is not limited to the above-described embodiments.

3 is a diagram illustrating a message transmission delay process that may occur during a RACH transmission procedure.

As described above, the UE can acquire the control information for the RACH transmission procedure through the RRC connection. Thereafter, if there is data to be transmitted, the terminal can select an ASC to use among a set of valid access service classes (ASC) of the MAC (Medium Access Control) layer of the terminal. At this time, the UE can select the Access Slot to be used in the Physical RACH (PRACH) based on the set ASC. That is, the ASC may be information on a valid available Access Slot. In this case, for example, the ASC may include an identifier and a Persistence value for identifying a specific part of the PRACH part. In this case, for example, the identifier may indicate an access slot as described above. In addition, the Persistence value may indicate whether the RACH transmission procedure is performed in the current TTI (Transmission Time Interval). At this time, the UE performs Persistence check based on the Persistence value and can determine whether to perform the RACH transmission procedure in the current TTI based on the Persistence value, which will be described later.

If the UE determines an Access Slot based on the ASC, the UE can initialize the preamble transmission counter and transmit the preamble to the UTRAN. If the UE fails to transmit a preamble, it can increase the counter for preamble transmission. At this time, if the preamble transmission counter is equal to or greater than the threshold value, the UE indicates through the upper layer that the preamble transmission has exceeded the threshold value, and transmits a message about the transmission failure through the upper layer. That is, if the UE fails to transmit a preamble more than a predetermined number of times, it can be considered that the transmission has failed. At this time, the threshold value may be a threshold value and may have a certain error.

If the preamble transmission counter is less than or equal to the threshold value, the UE can update the control information for the RACH transmission procedure. After that, the terminal can set a timer. Here, for example, the timer may be a time for one TTI. That is, the UE can apply the update information on the RACH transmission procedure to one TTI. The terminal may then perform a Persistence check based on the Persistence value. In this case, for example, the UE can compare the Persistence value with an arbitrary value. At this time, the Persistence check may indicate whether or not the RACH transmission procedure is performed, as described above. In this case, if an arbitrary value is smaller than the Persistence value, the UE determines that the Persistence check is " failed ", and does not perform the RACH transmission procedure. Thereafter, the UE can perform the Persistence check in the next TTI. At this time, the Persistence check can be repeatedly performed until it is "pass". That is, the Persistence check may indicate whether the RACH transmission procedure can be performed in each TTI.

If the Persistence check is " allowed ", the UE can perform the RACH transmission procedure. At this time, the MAC layer of the UE can provide the physical layer information on the access slot based on the result of the ASC operation. Then, the terminal can transmit the preamble through the physical layer. At this time, the UE can receive a response message for the transmitted preamble through an Acquisition Indication Channel (AICH). At this time, if the UE receives an ACK (acknowledge) message, the UE can transmit data or a message using the physical layer. In this case, for example, the physical layer of the UE can provide information on the ACK message to the MAC layer. In addition, for example, the MAC layer of the UE can provide information on an ACK message to an upper layer. Thereafter, the UE can transmit the corresponding data or message through the physical layer, thereby terminating the RACH transmission procedure.

On the other hand, when the UE receives a Negative Acknowledgment (NACK) message, the UE can transmit data or a message in the next TTI. In this case, for example, the UE may back off the next TTI based on the set timer, and then start a new RACH transmission procedure in the next TTI. In another example, if an ACK / NACK message is not received, the UE can transmit data or a message in the next TTI. In this case, for example, the UE may back off the next TTI based on the set timer, and then start a new RACH transmission procedure in the next TTI.

As described above, the RACH transmission procedure can be performed. In this case, for example, referring to FIG. 3, a UE can perform transmission for an RLC PDU during a polling period. Thereafter, the RLC layer of the UE can set the Poll bit. At this time, if the Poll bit is set by the RLC layer, the UE can receive the RLC status report as a response message to the Poll bit from the UTRAN. That is, the UE can receive the RLC status report based on the Poll bit.

In this case, for example, when the UE receives the RLC status report with a delay of 10 ms or more, the MAC layer of the UE can start a new RACH transmission procedure for the retransmission RLC PDU (S310). That is, If the RLC status report is not received, the MAC layer of the UE may start a new RACH transmission procedure to retransmit the RLC PDU.

In this case, for example, when the RACH transmission procedure is started as described above, Persistence check can be performed. At this time, if the Persistence check is " failure ", the UE can retransmit the RLC PDU to the UTRAN at the next TTI without performing the retransmission at the current TTI, The procedure of transmitting the PDU may be delayed. The UE may then receive an RLC ACK (acknowledge) for the previous RLC PDU.

At this time, as described above, the initiated RACH transmission procedure can proceed without being canceled. More specifically, the terminal can perform the Persistence check based on the RACH transmission procedure in each TTI. At this time, if the Persistence check is " failure ", the UE does not perform retransmission of the RLC PDU to the UTRAN but performs Persistence check again in the next TTI, so that a transmission delay may occur (S330) Retransmission for the RLC PDU can be performed in the TTI where the Persistence check is " allowed ". The UE may transmit the new data in the next TTI after the retransmission of the RLC PDU previously attempted to be transmitted (S340). However, since the UE has received the ACK for the previous RLC PDU from the UTRAN, the RLC PDU Lt; RTI ID = 0.0 > retransmission < / RTI > In addition, since the UE must perform transmission of new data after a new RACH procedure started by the retransmission is completed, a transmission delay may occur and wasted radio resources may occur.

4 is a diagram illustrating a method of performing a RACH transmission procedure based on the presence / absence of a transmission message. As described above with reference to FIG. 3, an unnecessary RACH procedure can be attempted by retransmission of an RLC PDU. Accordingly, the UE can perform the determination as to whether or not the RLC PDU exists based on the Persistence check.

More specifically, referring to FIG. 4, if the Persistence check is 'failure', the MAC layer of the UE can check whether the RLC PDU to be transmitted still exists (S410). At this time, the RLC ACK for the RLC PDU When receiving, the UE can determine that there is no RLC PDU to be retransmitted. At this time, the UE can determine whether to terminate the RACH transmission procedure based on the first preamble transmission counter value. The UE may terminate the RACH transmission procedure if the value of the preamble transmission counter is 1 and there is no RLC PDU to be transmitted (S420). That is, the UE attempts to transmit a preamble for the first time and receives an ACK for the RLC PDU If there is no RLC PDU required to be transmitted, a newly initiated RACH transmission procedure may be unnecessary. Therefore, if the Persistence check is " failure ", the UE can terminate the newly started RACH transmission procedure based on the presence of the preamble transmission counter and the RLC PDU.

In addition, for example, if the Persistence check is " allowed ", the UE can retransmit the RLC PDU and terminate the procedure. In addition, if the UE does not have an RLC PDU or if the preamble transmission counter is not 1, the UE can perform a new Persistence check in the next TTI (S430). At this time, And so on. That is, if the UE can not determine whether retransmission for the RLC PDU is necessary because it can not receive the RLC ACK, it can perform the persistence check in the next TTI. Also, if the UE is attempting to transmit a preamble based on the preamble transmission counter, it may determine that there is a preamble to be transmitted, and perform a new Persistence check on the next TTI.

Thus, the terminal can cancel the unnecessary RACH transmission procedure. Accordingly, the UE can reduce the Persistence check time required for retransmitting the RLC PDU, the backoff time corresponding to the NACK / NO ACK of the AICH, and the delay time for the delay time based on the preamble attempt.

5 is a diagram illustrating a method of canceling a RACH transmission procedure between a UE and a UTRAN.

5 is a diagram showing an example in which the RACH transmission procedure is canceled based on the above-described configuration. Referring to FIG. 5, the UE may transmit a RLC PDU to the MAC layer by setting a Poll bit when the polling period ends. At this time, if the RLC layer does not have an RLC PDU to be retransmitted, the UE sets a Polling bit as a last SN (Sequence Number) of the polling period and transmits the RLC PDU to the MAC layer at step S510. At this time, SFN 11), the RLC layer of the UE may store data or a message in the RLC buffer in order to retransmit it, when the status report is not received as a response to the SN transmitted to the UTRAN in the previous TTI (Air Time SFN 10). (S520). The MAC layer of the UE can start a new RACH transmission procedure since there is an RLC PDU that can transmit in the current TTI (Air Time SFN 11). That is, the UE can start a new RACH transmission procedure for data or messages stored for retransmission. In this case, for example, when the UE performs the Persistency check, the Persistence check may be " Failed ". In this case, for example, if the persistence check is " failure ", the preamble transmission counter is not 1 or there is an RLC PDU to be transmitted. At this time, the MAC layer of the UE can perform a new Persistence check in the next TTI (S530). That is, when the UE performs Persistence check in the current TTI (Air Time SFN 11), the RLC PDU data or message is stored , The RACH transmission procedure may not be canceled even if the Persistence check is " failed ". Thereafter, the RLC layer of the UE can receive a status report from the UTRAN in the next TTI (Air Time SFN 12). At this time, the RLC layer of the UE can delete the RLC PDU stored for retransmission (S540) . At this time, the MAC layer of the UE can perform Persistency check in the current TTI (Air Time SFN 12). At this time, if the Persistence check result is " FAIL ", the UE determines whether there is data or a message for the RLC PDU If the RLC PDU is deleted, the RACH PDU may not be able to transmit data or a message for the RLC PDU. In this case, the UE cancels the RACH transmission procedure The UE may further detect whether the preamble transmission counter is 1 in the absence of the data or message for the RLC PDU. At this time, the UE can not determine whether the RLC PDU data or the message does not exist, The RACH transmission procedure currently in progress can be canceled only when the preamble transmission counter is 1. (S550) After that, the UE transmits a new RACH transmission procedure in the next TTI (Air Time SFN 13) , Which is described above.

6 is a flowchart illustrating a method of canceling a RACH transmission procedure according to an embodiment of the present invention.

The UE may start the first RACH transmission procedure and transmit the first message in the first TTI. (S610) At this time, as described above with reference to FIGS. 3 to 5, the UE determines whether to perform the RACH transmission procedure by performing Persistence check . Also, the first message may be a message or data set based on the RLC layer. That is, the first message may be a message or data for an RCL PDU. The RLC layer of the UE transmits an RLC PDU to the MAC layer, and the MAC layer can transmit data to the UTRAN through the physical layer. Also, as an example, the first message may be a message set to the UTRAN by a Poll bit setting.

Next, the UE can confirm whether it has received the response message for the first message (S620). At this time, the response message may be a status report received from the UTRAN, as described above with reference to FIGS. That is, the UE sets a Poll bit and transmits a message or data to the UTRAN, and receives a status report as a response message. At this time, if the UE receives the response message, it may not perform the retransmission for the RLC PDU. In addition, for example, if the UE receives the response message within a predetermined time, it may not perform the retransmission for the RLC PDU. At this time, the predetermined time may be an arbitrary value. For example, the predetermined time may be one TTI and is not limited to the above-described embodiment.

Next, when the UE does not receive the response message for the first message, the UE can start the second RACH transmission procedure in the second TTI for the first message retransmission (S630). At this time, The UE can receive the status report from the UTRAN with a delay of a predetermined time or longer. In this case, for example, the second TTI may be the next TTI of the first TTI. That is, if the response message for the RLC PDU transmitted in the first TTI is not received in the second TTI, which is the next TTI, the UE can start a new RACH transmission procedure. At this time, as described above, the RLC layer of the UE can store the data or message for the RLC PDU in the RLC buffer. At this time, the MAC layer of the UE can start the RACH transmission procedure based on the data or message for the stored RLC PDUs.

Next, the UE can perform Persistence test to check whether Physical RACH can be used (S640). At this time, the Persistence test may be the Persistence check described above. That is, the UE can determine whether to perform the Physical RACH transmission procedure by performing Persistence test. In this case, for example, Persistence test may be performed in the next TTI of the second TTI.

Next, if the Persistence test result is pass, the UE can transmit the first message using the Physical RACH (S650). At this time, if the Persistence test is " Pass "Quot;, the UE can perform the RACH transmission procedure. That is, the UE can perform the second RACH transmission procedure and retransmit the first message. Thus, the UE can perform retransmission of the first message and transmit new data or a message to the UTRAN in the next TTI.

Next, if the Persistence test result is fail, the UE can determine whether retransmission of the first message is required (S660). If retransmission is required, Persistence test can be performed again in the next TTI. On the other hand, if retransmission is not required, the UE can cancel the second RACH transmission procedure. (S670) At this time, as described above with reference to FIGS. 3 to 5, if the Persistence check is " The UE can cancel the second RACH transmission procedure if retransmission of the first message is not required. At this time, as described above, the first message may be data or message for the RLC PDU stored in the RLC buffer. At this time, the terminal can receive a status report as a response message to the first message. Upon receiving the status report, the RLC layer of the UE can delete the data or the message for the RLC PDU stored in the buffer for retransmission. At this time, the UE can determine that the retransmission of the RLC PDU is not required. That is, when the MS receives the response message for the first message, it can determine that the retransmission of the first message is not required. At this time, since the UE does not need to retransmit the RLC PDU, the UE can cancel the second RACH transmission procedure.

In addition, for example, the UE can cancel the second RACH transmission procedure only when the UE does not need retransmission for the first message and is the first transmission attempt for the first message. That is, as described above, if the preamble transmission counter is 1 and retransmission for the RLC PDU is not required, the UE can cancel the second RACH transmission procedure.

Also, for example, if the UE needs retransmission of the first message or if the preamble transmission counter is not 1, the UE can check whether a message can be transmitted in the next TTI. That is, the UE may perform a new Persistence check by backing off to the fourth TTI.

7 is a block diagram of a terminal device according to an embodiment of the present invention.

The terminal 100 includes a transmission module 110 for transmitting a radio signal to an external device, a reception module 130 for receiving a radio signal from an external device, a processor 120 for controlling the transmission module 110 and the reception module 120, ). At this time, as an example, the external device may be a base station. In addition, for example, the external device may be a device or a device capable of performing communication with the terminal, and is not limited to the above-described embodiment. Also, according to one embodiment of the present disclosure, the base station may be a base station included in at least one of E-UTRAN, GERAN, and UTRAN.

The terminal 100 can transmit and receive digital data such as contents using the transmission module 110 and the reception module 130. [

According to one embodiment of the present disclosure, the processor 120 may initiate a first RACH transmission procedure using the transmission module 110 to transmit a first message in a first transmission time interval (TTI). In addition, if the processor 120 fails to receive a response message for the first message using the reception module 130, the processor 120 may transmit the second RACH message in the second TTI for retransmission of the first message using the transmission module 110, The transmission procedure can be started. In addition, the processor 120 can determine whether physical RACH can be used through Persistence test. At this time, if the Persistence test is failed, the processor 120 can cancel the second RACH transmission procedure if retransmission of the first message is not required. In this case, for example, the second RACH transmission procedure may be canceled only when retransmission of the first message is not required, and is the first transmission attempt for the first message. For example, if the physical RACH is unavailable in the current TTI based on the Persistence test and the retransmission of the first message is required, the Persistence test is performed in the third TTI that is the next TTI of the current TTI to use the Physical RACH You can check whether you can. At this time, if the RLC layer does not receive the response message for the first message, the RLC layer may store the first message in the RLC buffer for retransmission of the first message. At this time, the RLC layer can delete the first message stored in the RLC buffer upon receiving the response message. In addition, the processor 120 may determine that retransmission of the first message is not necessary if the RLC data is deleted before confirming whether the message can be transmitted. Also, as an example, the response message may be a status report and is not limited to the above-described embodiment.

The above-described embodiments of the present invention can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may be implemented in one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs) , FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The foregoing description of the preferred embodiments of the present invention has been presented for those skilled in the art to make and use the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention.

In this specification, both the invention and the method invention are explained, and the description of both inventions can be supplemented as necessary.

100: terminal device
110: Transmission module
120: Processor
130: Receiving module

Claims

A method of canceling a Random Access Channel (RACH) transmission procedure by a UE in a wireless communication system,
Initiating a first RACH transmission procedure and transmitting a first message in a first transmission time interval (TTI);
If a response message to the first message is not received, starting a second RACH transmission procedure in a second TTI for retransmission of the first message; And
Checking whether a physical RACH is available in the current TTI using a Persistence test,
And cancels the second RACH transmission procedure if retransmission of the first message is not necessary when the physical RACH is unavailable in the current TTI based on the Persistence test.

The method according to claim 1,
Wherein the second RACH transmission procedure is canceled only when it is the first transmission attempt for the first message.

The method according to claim 1,
If the physical RACH is unavailable in the current TTI based on the Persistence test, if retransmission of the first message is required, the Persistence test is performed in the third TTI, which is the next TTI of the current TTI, The RACH transmission procedure cancellation method.

The method according to claim 1,
Wherein the first message is a message set based on an RLC (Radio Link Control) PDU (Protocol Data Unit).

5. The method of claim 4,
If the RLC layer does not receive the response message for the first message, the RLC layer stores the first message in the RLC buffer for retransmission of the first message,
And upon receipt of the response message, deletes the first message stored in the RLC buffer.

6. The method of claim 5,
And if the first message is deleted from the RLC buffer, retransmission of the first message is not necessary.

The method according to claim 6,
Wherein the response message is a status report.

A terminal apparatus for canceling a RACH (Random Access Channel) transmission procedure in a wireless communication system,
A receiving module for receiving a message from an external device;
A transmission module for transmitting a message to an external device; And
A processor for controlling the receiving module and the transmitting module,
The processor comprising:
A first RACH transmission procedure is started using the transmission module and a first message is transmitted in a first transmission time interval (TTI)
When a response message to the first message is not received using the receiving module, a second RACH transmission procedure is started in a second TTI for retransmission of the first message using the transmitting module,
Persistence test is used to check whether the physical RACH is available in the current TTI,
And cancels the second RACH transmission procedure if retransmission of the first message is not necessary when the physical RACH is unavailable in the current TTI based on the Persistence test.

9. The method of claim 8,
Wherein the second RACH transmission procedure is canceled only when the first transmission attempt to the first message does not require retransmission for the first message.

9. The method of claim 8,
If the physical RACH is unavailable in the current TTI based on the Persistence test, if retransmission of the first message is required, the Persistence test is performed in the third TTI, which is the next TTI of the current TTI, And canceling the RACH transmission procedure.