KR101221443B1 - Method and apparatus for discontinuous reception of a connected terminal in mobile communication system - Google Patents

Abstract

The present invention relates to a method and apparatus for efficiently performing a discontinuous reception (DRX) operation by a terminal in a connected state in a mobile communication system. The method for discontinuous reception of a mobile terminal connected to a base station of a mobile communication system includes a discontinuous reception cycle length (DRX cycle length), information capable of deriving a starting point of an activation period, and a minimum from the base station. Receiving a minimum active period length, deriving a start time of an activation period by using information from which a start time of the activation period is derived, and at the start of the activation period, Driving a timer having a continuous reception cycle length (DRX cycle length) and a timer having a minimum active period length input therein, and checking whether there is a packet to be received by the terminal through a common control channel; And a last packet indicator indicating that the received packet is the last packet when the packet is received. Checking whether the packet includes the last packet indicator, and if a packet including the last packet indicator information is received, radio link control to a point at which the packet including the last packet indicator information is received. : RLC) configuring a RLC Status Report including packet data unit (PDU) reception status information, and after the configured radio link control status report is transmitted, sleeps until the next activation period begins Including the process to enter the mode.

DRX, sleep period, active period, last packet indicator

Description

METHOD AND APPARATUS FOR DISCONTINUOUS RECEPTION OF A CONNECTED TERMINAL IN MOBILE COMMUNICATION SYSTEM}

1 is a view showing the structure of an LTE system,

2 is a diagram illustrating a conventional DRX operation;

3 is a view schematically illustrating the present invention;

4 is an operation flowchart of a terminal when an end of an activation period is signaled in band according to a first embodiment of the present disclosure;

5 is a flowchart illustrating an operation of a terminal when an end of an activation period is signaled through a forward control channel according to a second embodiment of the present disclosure;

6 is an operation flowchart when the terminal determines the end of the activation period based on the forward activity according to a third embodiment of the present invention;

7 is a block diagram of a terminal receiving apparatus according to the first to third embodiments of the present invention.

8 is a view schematically illustrating a fourth embodiment of the present invention;

9 is a block diagram of a terminal receiving apparatus according to a fourth embodiment of the present invention;

10 is a flowchart illustrating a terminal operation according to a fourth embodiment of the present invention.

The present invention relates to a method and apparatus for setting an activation period in a wireless communication system, and more particularly, to a method and apparatus for efficiently setting an activation period during a discontinuous reception period in a mobile communication system using discontinuous reception.

In general, a wireless communication system is a system developed for a case in which a fixed wired network cannot be connected to a terminal and used. Representative systems of such a wireless communication system include a mobile communication system, a wireless LAN, Wibro, a mobile ad hoc, and the like.

 Unlike general wireless communication, mobile communication assumes mobility of a user. The ultimate goal of mobile communication is to exchange information media at any time, anywhere, and anywhere using terminals such as mobile phones and pagers.

A representative method of such mobile communication is a cellular system. The cellular system divides a service area into a plurality of cells and installs one radio base station (cellular base station) in which a different frequency is assigned to an adjacent cell for each cell so that the same frequency can be reused. In this case, a service area by one wireless base station is called a cell, and thus, a unit service area is divided into cells and is called a cellular system.

Among the cellular systems, the first technology is an analog method such as Advance Mobile Phone System (AMPS) and Total Access Communication Services (TACS), which is called first generation mobile communication. The first generation of mobile communication systems has made it difficult to accommodate the rapidly increasing subscribers of mobile communication services, and the development of technology has increased the demand for various services as well as previous voice services. Due to these demands, digital second generation mobile communication has emerged more advanced than first generation mobile communication. Unlike the analog system, the second generation mobile communication system digitalizes an analog voice signal, performs a voice encoding, and uses a digital modulation and demodulation method, and uses a frequency of 800 MHz. The multiple access method uses a time division multiple access (TDMA) method and a code division multiple access (CDMA) method. In the second generation mobile communication system, voice services and low-speed data services are provided, and there are IS-95 (CDMA), IS-54 (TDMA), and GSM (Global System for Mobile communication) systems in the United States. In addition, PCS (Personal Communication Services) system is classified as a 2.5 generation mobile communication system, and uses a frequency of 1.8 ~ 2GHz band. These second generation mobile communication systems have been established for the purpose of increasing the efficiency of mobile communication systems while providing voice services to users. However, the emergence of the Internet and the demand for high-speed data services of users foreshadowed the emergence of a new wireless platform, which is a third generation mobile communication such as IMT-2000 (International Mobile Telecommunication-2000). The IMT-2000 is largely divided into a synchronous asynchronous method and a synchronous method, and a representative system of the asynchronous method is Universal Mobile Telecommunication Systems (UMTS) or Wideband CDMA (W-CDMA) of 3GPP (3rd Generation Partnership Project). The system includes CDMA 2000 1x of 3rd Generation Partnership Project 2 (3GPP2), CDMA 2000 1x Evolution Data Only (EV-DO), CDMA 2000 1x Evolution of Data and Voice (EV-DV), and the like.

Long Term Evolution (LTE) is under discussion at 3GPP, which is in charge of UMTS standardization. LTE is a technology that implements high-speed packet-based communication of about 100 Mbps, aiming for commercialization in 2010. To this end, various methods are discussed. For example, the network structure can be simplified to reduce the number of nodes located on the communication path, or the wireless protocols can be as close to the wireless channel as possible. As a result, the structure of LTE is expected to change from the existing four-node structure to a two-node or three-node structure.

Although the present invention has been described with reference to LTE application, it can be applied to all mobile communication systems using discontinuous reception without any modification.

1 is a diagram illustrating the structure of an LTE system. For example, in LTE, as shown in FIG. 1, a two-node structure of an Evolved Node B (ENB) 100a, 100b, 100c, 100d and 100e and an Evolved Gateway GPRS Serving Node (EGGSN) 102a and 102b is shown in FIG. 1. Can be simplified.

The ENBs 100a, 100b, 100c, 100d, and 100e are nodes corresponding to the existing Node Bs and are connected to the UE 104 by a wireless channel. Unlike the existing Node B, ENB plays a more complex role. In LTE, all user traffic, including real-time services such as VoIP, will be serviced via a shared channel, which means that a device is needed to collect and schedule situation information of UEs 104. In charge of. Similar to High-Speed Downlink Packet Access (HSDPA) or Enhanced Uplink Dedicated Channel (EDCH), LTE ARQ is performed between ENB and UE in LTE. LTE is expected to use Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology in the 20 MHz bandwidth to achieve transmission rates up to 100 Mbps. In addition, an adaptive modulation & coding (AMC) scheme that determines a modulation scheme and a channel coding rate according to the channel state of the terminal will be applied.

HARQ is a technique of increasing reception success rate by soft combining with retransmitted data without discarding previously received data. HARQ is used to increase transmission efficiency in high-speed packet communication such as HSDPA (High Speed Downlink Packet Access) and EDCH (Enhanced Dedicated Channel). LTE also uses HARQ between a terminal and a base station.

In the related art, discontinuous reception (hereinafter, referred to as 'DRX') has been mainly used as a means for increasing the waiting time of an idle state terminal. The terminal wakes up at a predetermined time (Wake up), monitors a predetermined channel for a predetermined period, and repeats the operation of entering the sleep mode again.

2 is a diagram illustrating a conventional DRX operation.

Referring to FIG. 2, the terminal and the base station agree on the DRX configuration and repeat the sleep period and the activation period accordingly. The sleep period is a period in which the terminal turns off the receiver and minimizes power consumption, and the activation period is a period in which the terminal turns on the receiver and performs a normal reception operation. The activation period is also referred to as a wake-up period, and throughout this specification, the activation period is used synonymously with the wake-up period.

DRX configuration generally consists of the following elements.

Distance between successive activation periods and activation periods (DRX cycle length 210, 220): Distance between any activation period and the next activation period, the longer the DRX cycle length, the longer the sleep period, and also the power consumption of the terminal Decreases. However, if the DRX cycle length is long, there is a disadvantage that the call delay for the terminal is increased. The DRX cycle length is signaled by the network.

Activation period start time (205, 215, 225): Typically derived from the unique identifier of the terminal and the DRX cycle length. For example, a value obtained by performing a mode operation on the identifier of the terminal by the DRX cycle length may be used as the start time of the activation period.

Length of activation period 235: refers to the length of the terminal waking period for one activation period, typically a predetermined value is used. For example, the length of the activation period in the UMTS communication system is 10 msec.

The terminal calculates the starting point of the activation period as shown by reference numeral 230 and the DRX cycle lengths 210 and 220, and receives a forward signal during the activation period from the start point of the activation period. . If there is no desired information in the received forward signal, the receiver is turned off and enters the sleep period.

In LTE, a method of introducing DRX to a connected state terminal has been discussed. The connection state terminal is a terminal on which a specific service is running, and user data associated with the service is continuously exchanged between the network and the terminal. It is obvious that the DRX of the connection state terminal should be configured in consideration of the characteristics of the service being operated.

However, DRX in the classical sense of waking up at regular intervals and monitoring a predetermined channel for a certain period of time is not suitable for a connected state terminal. For the connection state terminal, the amount of data generated every DRX cycle may vary according to the type of service. In other words, the length of receiving a forward signal every DRX cycle needs to vary depending on the amount of data to be transmitted in the corresponding DRX cycle. For example, when a terminal receives a file download service using TCP, one packet is initially transmitted in the forward direction due to the characteristics of TCP, and when the terminal transmits a TCP ACK, two packets are transmitted again. There is a tendency to increase the amount of forward data with a certain time difference, such as four packets are transmitted again due to the TCP ACK. In this case, it is desirable to extend the activation period continuously.

Even if it is not a file download service, the inaccuracy and discontinuity of data generation are common characteristics of the packet service. As such, in the packet service, the traffic occurrence situation may change every DRX cycle.

The present invention provides an apparatus and method for adjusting the length of an activation period to meet traffic requirements.

In the method of discontinuous reception of a mobile station connected to a base station of a mobile communication system according to the present invention, a discontinuous reception cycle length (DRX cycle length), a starting point of an activation period can be derived from the base station. Receiving information and a minimum active period length, deriving a start time of the activation period using information capable of deriving the start time of the activation period, and inducing the induced activation period. Driving a timer input with the discontinuous reception cycle length (DRX cycle length) and a timer input with the minimum active period length at a start point of time, and received by the terminal through a common control channel; Checking whether a packet exists, and when the packet is received, a last packet flag of the received packet (Last Pac). ket flag), and when the last packet indicator is set to a preset value, the packet reception is completed and the device enters the sleep mode until the next activation period starts.

In the method of discontinuous reception of a mobile station connected to a base station of a mobile communication system according to the present invention, a discontinuous reception cycle length (DRX cycle length), a starting point of an activation period can be derived from the base station. Start of the activation period by using the information present, the process of receiving a minimum active period length and an active period end interval, and information that can be used to derive the start of the activation period. Deriving a time point, driving a timer inputted with the DRX cycle length and a timer inputted with the minimum active period length at the start of the activation period; Checking whether there is a packet to be received by the terminal through a control channel; and when the packet is received, the number of packets Re-starting the timer T (active_period_end) for terminating the activation period according to the new situation, and if the timer for terminating the activation period expires, complete processing of Hybrid Automatic Repeat reQuest (HARQ) packets, Entering sleep mode until the next activation period begins.

A mobile terminal device in a connected state performing discontinuous reception from a base station of a mobile communication system according to the present invention comprises a receiver for receiving a packet from the base station, a HARQ packet received by the receiver, and an error. An HARQ processor for transmitting a HARQ packet without a decoded HARQ packet, the demultiplexer for checking a last packet flag included in the HARQ packet and transmitting whether the last packet flag is set to a DRX controller, and the demultiplexer And receiving the report that the last packet flag is set, the DRX controller for controlling whether to turn off the receiver by checking that the operation of the HARQ processor is completed.

In the method of discontinuous reception of a mobile station connected to a base station of a mobile communication system according to the present invention, a discontinuous reception cycle length (DRX cycle length), a starting point of an activation period may be derived from the base station. Receiving the information and the minimum active period length, and deriving the start time of the activation period by using the information from which the start time of the activation period is derived; Driving a timer having the DRX cycle length inputted and a timer having the minimum active period length inputted at a starting point; and a packet to be received by the UE through a common control channel Checking whether there is an error message, and when the packet is received, indicating that the received packet is the last packet. Checking whether the packet including the last packet indicator information is included; and if the packet including the last packet indicator information is received, control the radio link to the point where the packet including the last packet indicator information is received. Radio link control (RLC) packet data unit (PDU) receiving a radio link control status report (RLC Status Report) comprising the status information, and after the configured radio link control status report after transmitting the next activation period is to start It involves the process of entering into sleep mode until.

A mobile terminal device in a connected state performing discontinuous reception from a base station of the mobile communication system according to the present invention operates in at least one discontinuous reception mode implemented in the mobile terminal device, and among the packets transmitted by the base station during an activation period. When receiving a packet including the last packet indicator, a Radio Link Control entity constituting a radio link status report including reception status information of received radio link control packets, and transmitting / receiving packets with the base station. And a transceiver configured to transmit the HARQ packet to the demultiplexer / multiplexer after performing HARQ processing on the packets received by the transceiver, and the MAC received from the demultiplexer / multiplexer. A HARQ processor for transmitting a packet to the transceiver unit through a HARQ operation, and the radio link system A demultiplexing / multiplexing apparatus for multiplexing a packet transmitted from an entity to the HARQ processor or demultiplexing a packet received from the HARQ processor to the radio link control entity, and an activation period from the radio link control entity When receiving a signal that the signal has been terminated, the mobile terminal device maintains the sleep state until the end of the activation period and starts the next activation period, and when the start point of the activation period is recognized when the start of the activation period is moved A DRX control unit for turning on a terminal device, and a control channel processing unit for processing information received through a forward common control channel, and reporting a packet transmitted to the mobile terminal device to the DRX control unit when there is a packet.

The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

In the present invention, the DRX cycle length 310, information for deriving the start time 305 of the activation period, and the minimum active period length 340a and 340b are signaled from the base station to the terminal. The terminal wakes up at each of the start points 305, 320, and 325 of each activation period, if there is no data to receive, maintains the minimum activation period and enters the sleep mode, and if there is data to receive, until the data is received. After maintaining the activation period, go back to sleep mode.

3 is a view schematically illustrating the operation of the present invention. The terminal induces the start time 305 of the activation period by using a predetermined method, and starts the activation period when the start time 305 of the activation period is reached. The lengths of the activation periods 350, 360, and 370 may have a variable length from the minimum activation periods 340a and 340b to the DRX cycle lengths 310 and 380, and the terminal is forward when the activation period start time 305 is reached. Receive packets over the channel. In FIG. 3, reference numerals 340a and 340b representing the length of the minimum activation period denote physically the same time.

Referring to the activation period with reference numeral 360 in FIG. 3, it can be seen that packets are continuously received within the minimum activation period 340a. Therefore, the terminal can confirm that the activation period 360 is terminated by checking whether the received packet is the last packet through a predetermined method.

In FIG. 3, the reception of the packet may be performed by a predetermined method according to a communication system. For example, in the LTE system, the UE monitors whether there is a packet transmitted to the user through a forward control channel. If so, receive the packet.

In addition, referring to the activation period of reference numeral 370 in FIG. 3, the terminal waking up at the point of reference numeral 325 receives a packet during a predetermined minimum activation period 340b. However, in the activation period with reference numeral 370 of FIG. 3, since there is no packet transmitted to the terminal during the minimum activation period 340b, the terminal ends the corresponding activation period and stays in the sleep period until the next activation period begins.

On the other hand, as described above, when the terminal wakes up at the reference numeral 320 and recognizes the packet transmitted to the terminal before the minimum activation period 360 ends, the terminal starts receiving the packet from the base station. In fact, the end of the activation period (350, 360, 370) that the packet is transmitted and received to the terminal is given in the in-band (in band) information of the packet, or notified through the control channel. Alternatively, the terminal may detect the end of the activation period by itself according to a predetermined rule.

When given as in band information, the base station sets a 1-bit flag called 'Last Packet Flag' of the last packet of the corresponding activation period to 'YES' as shown by reference numeral 330. Therefore, when the terminal receives the packet with the 'Last Packet Flag' set to YES, the terminal maintains an activation period until the reception of the packets being processed by the HARQ processor is completed, and then the reception of the packets is stopped. Upon completion, the device enters a sleep mode 390.

When the end of the activation period is notified through the control channel, the terminal maintains the activation period until reception of packets being processed by the HARQ processor is completed at the time when the end of the activation period is declared, When the reception is completed, the user enters the sleep period.

The terminal detects the end of the activation period through a predetermined rule, and can be implemented in various ways. For example, the terminal determines that the activation period has ended when no packet is received for a predetermined length of time. can do.

As described above, if there is no packet reception, the length of the activation period is minimized to the minimum activation period. If there is a packet reception, the end of the activation period is signaled in band or out of band. band) or by allowing the UE to determine itself, the length of the activation period can be flexibly adjusted as needed. According to the present invention, when the end time of the activation period is signaled in in band, the first embodiment, and when the signal is signaled out of band, in the second embodiment, the terminal activates the activation period based on the forward activity. Determining the end of P2 will be described as a third embodiment. In addition, in the present invention, In band refers to a case where information is transmitted in a base station by including information in a user packet, and Out of band indicates a case where information is transmitted through a separate channel.

4 is a flowchart illustrating an operation of a terminal when an end of an activation period is signaled in band according to a first embodiment of the present invention. The first embodiment illustrates the operation of the terminal when signaling the end of the activation period using the last packet flag.

First, in step 405, the UE prior to DRX operation, DRX cycle length (DRX cycle length), information that can derive the starting position (starting position) of the activation period, call setting the minimum active period (minimum active period length), etc. Receives through the process of.

In step 410, the terminal derives the starting point of the activation period by using a predetermined rule, using the information to derive the starting point of the activation period, and determines whether it is the start point of the current activation period. If it is not the start point of the current activation period in step 410, the terminal proceeds to step 435 until it reaches the start point of the activation period, and maintains the sleep period, and proceeds to step 415 when the start point of the activation period is reached. The UE derives the initial activation period start time in a predetermined manner, and once the start point of the activation period is recognized, the subsequent activation period starts at a point away from the start point of the previous activation period by DRX cycle length.

In step 415, the terminal drives the timers T (DRX_CYCLE_LENGTH) and T (MINIMUM_ACTIVE).

T (DRX_CYCLE_LENGTH) is a timer in which the DRX cycle length recognized in step 405 is input, and T (MINIMUM_ACTIVE) is a timer in which the minimum activation period recognized in step 405 is input.

In step 420, the terminal monitors whether there is a packet to be received through the common control channel.

If there is no packet transmitted to the terminal until T (MINIMUM_ACTIVE) expires, that is, until the minimum activation period ends in step 420, the terminal branches to step 435, enters the sleep mode, and the next activation period begins. Stay in sleep until The start of the next activation period is when the T (DRX_CYCLE_LENGTH) driven in step 415 expires.

On the other hand, if the check result of step 420 before the end of the minimum activation period, if there is a packet transmitted to the terminal, the terminal proceeds to step 425, and receives the packet according to the normal HARQ operation.

If the packet is successfully received in step 425, the terminal checks the last packet flag of the packet received in step 430. If the last packet flag is set to Yes in step 430, the process proceeds to step 440. If the last packet flag is set to no, the process returns to step 425 to continue packet reception.

In step 440, the processing of the HARQ packets being processed by the HARQ processor at that time is completed, and the process proceeds to step 435 and enters the sleep mode until the next activation period begins. The start of the next activation period is when the timer T (DRX_CYCLE_LENGTH) driven in step 415 expires.

Completion of the processing of the HARQ packets in step 440 is a result of HARQ operation on the packet stored in the HARQ processor, the error of the packet is resolved and the terminal transmits HARQ ACK to the base station, or the error packet Although not resolved, a new packet transmission may be signaled from the base station to the same HARQ processor, thereby failing to successfully receive the packet. In other words, the situation in which the packet stored in the HARQ processor has been successfully received or recognized that there is no possibility of successfully receiving the packet is when the processing of the packet stored in any HARQ processor is completed.

5 is a flowchart illustrating an operation of a terminal when an end of an activation period is signaled through a forward control channel according to a second embodiment of the present disclosure. Since the operation of the terminal according to the second embodiment of the present invention is the same as that of the first embodiment except for the operation of the terminal determining the end of the activation period, only the part in which other operations are performed according to the second embodiment will be described. do.

Therefore, steps 505 to 520 of FIG. 5 are the same as steps 405 to 420 of the first embodiment shown in FIG. 4, and thus will not be described.

In step 525, the terminal receives a packet from the base station according to a predetermined HARQ operation.

In this case, the terminal continuously receives the forward control channel and monitors whether a signal indicating the end of the activation period is signaled through the forward control channel in step 530.

In step 530, if a signal indicating the end of the activation period is received, the flow proceeds to step 540. Otherwise, the flow returns to step 525 to continue packet reception. In step 540, the UE completes the processing of HARQ packets being processed by the HARQ processor at that time. In step 535, the UE enters the sleep mode until the next activation period begins. The start of the next activation period is a time point when the T (DRX_CYCLE_LENGTH) driven in step 515 expires.

6 is an operation flowchart when the terminal determines the end of the activation period based on the forward activity according to the third embodiment of the present invention.

In the third embodiment of the present invention, prior to the DRX operation, the UE may induce a DRX cycle length, information for inducing a start time of an activation period, a minimum active period length, and an activation period end interval (active period) in step 605. end interval). At this time, the same value may be used for the minimum activation period and the activation period end interval, in which case only one value is signaled.

In step 610, the terminal derives the start time of the activation period, checks whether the activation period has started, and uses the information to derive the start time of the activation period, and if the activation period has not started, step 635. Proceed to and stay in sleep mode.

The start time of the activation period is initially derived through information capable of deriving the start time of the activation period, after which the start time of the activation period is a value obtained by adding the DRX cycle length to the start of the previous activation period.

When the UE reaches the start of the activation period, the UE proceeds to step 615 to drive T (DRX_CYCLE_LENGTH) and T (MINIMUM_ACTIVE).

T (DRX_CYCLE_LENGTH) is a timer in which the DRX cycle length recognized in step 605 is input, and T (MINIMUM_ACTIVE) is a timer in which a minimum activation period recognized in step 605 is input.

In step 620, the terminal checks whether there is a packet to be received through the common control channel. If the check result timer T (MINIMUM_ACTIVE) in step 620 expires, that is, no packet is transmitted to the user during the minimum activation period, the process branches to step 635 and enters the sleep mode until the next activation period begins. The start of the next activation period is when the timer T (DRX_CYCLE_LENGTH) driven in step 615 expires.

If the packet is transmitted to itself before the minimum activation period ends in step 620, the terminal proceeds to step 625 to receive the packet according to a normal HARQ operation.

In step 625, the terminal receiving the packet proceeds to step 627 and re-starts the timer T (active_period_end) according to the packet reception situation. T (active_period_end) is used to monitor the packet reception status of the terminal and to terminate the activation period if no packet is received for a predetermined period.

The activation period end timer value recognized in step 605 is input to T (active_period_end), and when the terminal receives a packet for the first time, the terminal drives the T (active_period_end) and restarts the T (active_period_end) whenever a subsequent packet is received. Drive.

Subsequent packet reception may have two meanings as follows.

1. Subsequent packet means new packet

2. Subsequent packets mean both new and retransmitted packets for conventional packets

That is, the timer T (active_period_end) may be restarted only when the subsequent packet is a new packet, and the T (active_period_end) may be restarted when the subsequent packet is a new packet as well as a retransmission packet for a conventional packet. . For convenience of description, T (active_period_end) is re-driven only when a new packet is received. First, T (active_period_end) is re-driven when a second packet is received, including a retransmission packet. .

In operation 630, the terminal determines whether T (active_period_end) has expired. The expiration of T (active_period_end) means that no packet was received during the activation period end interval. As long as T (active_period_end) does not expire, the terminal continuously performs steps 625 and 627.

In operation 640, the operation of the terminal varies depending on whether T (active_period_end) operates in the first or the second.

In case of operating inside the first terminal, the terminal completes processing of HARQ packets being processed by the HARQ processor at the corresponding time, and proceeds to step 635 to enter the sleep mode until the next activation period starts. The start of the next activation period is when the T (DRX_CYCLE_LENGTH) driven in step 615 expires.

When operating in the second, the terminal does not wait for the processing of the HARQ packets being processed in the HARQ processor, but immediately enters the sleep mode. This is because, in the second, the activation period end interval is set based on the reception of all forward packets including retransmission. In the second, since the terminal switches to the sleep mode if the base station does not perform retransmission within the activation period end interval, the base station and the terminal should perform retransmission for a specific packet during the activation period end interval.

In other words, if the retransmission packet does not arrive during the activation period end interval, it means that the base station has abandoned transmission of the packet, which means that the packet is unlikely to be successfully received. Therefore, packets stored in the processor for which the retransmission packet has not arrived during the activation period end interval are not likely to be processed in the future, and therefore discard and immediately enter the sleep mode.

7 is a block diagram of a terminal receiving apparatus 700 according to the first to third embodiments of the present invention.

The receiving apparatus 700 of the terminal is composed of a demultiplexing apparatus 705, a HARQ processor 715, a receiving unit 730, a DRX control unit 725, and a control channel processing unit 720.

The receiver 730 of the terminal is turned on or off under the control of the DRX controller 725. The DRX controller 725 turns off the receiver 730 in the sleep mode, and turns on the receiver 730 during the activation period. The HARQ processor 715 processes the HARQ packet received by the receiver 730 through a predetermined HARQ operation, and transmits the HARQ packet without an error to the demultiplexer 705.

The demultiplexer 705 checks the received packet packet and reports the last packet flag to the DRX controller 725 if the last packet flag is set to 'yes'. In addition, the demultiplexer 705 forwards the received packet to a higher layer, not shown.

When the DRX controller 725 recognizes that the packet having the Last Packet Flag is 'yes' is received, the DRX controller 725 checks the state of the HARQ processor 715, and when the operation of the HARQ processor 715 is completed, enters the sleep mode. Plunge That is, the receiver 730 is turned off. The control channel processor 720 processes information received through the forward common control channel. As in the second embodiment, if the end of the activation period is signaled through the forward common control channel, the control channel processor 720 reports the end of the activation period to the DRX controller 725.

When the DRX controller 725 receives the fact that the activation period has ended from the control channel processor 720, the DRX controller 725 checks the state of the HARQ processor 715, and when the operation of the HARQ processor 715 is completed, enters the sleep mode. . That is, the receiver 730 is turned off.

However, as described above, when the terminal device 700 receives the last packet as described above, when the terminal 700 receives the last packet, the terminal apparatus 700 transmits the positive recognition signal of the RLC level rather than immediately entering the sleep mode. It is preferable to enter the sleep mode later.

This is because, in most cases, the packet service operates in Radio Link Control (RLC) Acknowledgment Mode, which performs an Automatic Retransmission Request (ARQ) operation to increase the reliability of transmission and reception. In the ARQ operation, the sender inserts a serial number into a packet and transmits it.The receiver checks the received packet serial number to determine whether there is an unreceived packet, and sends a negative acknowledgment signal (NACK) to the unreceived packet. It requests retransmission and transmits an acknowledgment (ACK) for a successfully received packet. The negative acknowledgment signal and the positive acknowledgment signal are stored in a control message called an RLC status report and transmitted.

If the service configured for discontinuous reception operates in the RLC acknowledgment mode, when receiving the last packet, the terminal should transmit a positive acknowledgment signal of the RLC level. Therefore, it is preferable to enter the sleep mode after transmitting the RLC level positive acknowledgment signal rather than entering the sleep mode immediately after receiving the last packet.

Accordingly, unlike the first embodiment described above, an embodiment in which the terminal device enters the sleep mode after receiving the last packet indicator and transmitting the RLC acknowledgment signal for the last packet will be described as the fourth embodiment. do.

8 is a diagram schematically illustrating a fourth embodiment of the present invention.

In the fourth embodiment of the present invention, since the operation of the terminal is the same as in the first embodiment during the activation period in which no packet is received, description thereof is omitted. In the fourth embodiment of the present invention, as in the above-described embodiments, the DRX cycle length 810, information for deriving the start time 805 of the activation period from the base station to the UE, and minimum activation periods 840a and 840b may be used. Information is signaled. The terminal wakes up at the start points 805, 820, and 825 of each activation period and enters the sleep mode after maintaining the minimum activation period if there is no data to receive, and if there is data to receive, until the data is received. After maintaining the activation period, go back to sleep mode.

In FIG. 8, the terminal induces the start time 805 of the activation period by using a predetermined method, and starts the activation period when the start time 805 of the activation period is reached. The lengths of the activation periods 850, 860, and 870 may have a variable length from the minimum activation periods 840a and 840b to the DRX cycle length 810. Receive packets via In FIG. 8, reference numerals 840a and 840b representing the length of the minimum activation period indicate physically the same time.

Referring to the activation period with reference numeral 860 in FIG. 8, it can be seen that packets are continuously received within the minimum activation period 840a. Therefore, the terminal can confirm that the activation period 860 is terminated by checking whether the received packet is the last packet through a predetermined method.

In the first embodiment of the present invention and the fourth embodiment of the present invention, the terminal operation difference in the activation period in which the packet is received is as follows.

In the first embodiment, when the reception of the packet containing the information of the last packet is completed, the corresponding activation period ends and enters the sleep mode.

In the fourth embodiment, a packet containing information of the last packet is received, all packets having a serial number lower than the last packet are successfully received, and all packets having a serial number lower than the last packet are received. After sending a positive acknowledgment signal, the activation period ends and the device enters sleep mode.

Looking at the activation period of the reference numeral 860, the terminal wakes up at the start of the predetermined activation period to monitor the forward control channel. When the packet is transmitted to the terminal through the forward control channel and the forward direction before the minimum activation period 840a ends, when the terminal receives the packet 880 containing the 'last packet indicator' Continue receiving packets forward. The 'last packet indicator' may be implemented as an RLC control signal.

When the RLC serial numbers of the packets are x to x + n, the RLC entity 945 of the UE, which will be described later with reference to FIG. 9, checks the serial numbers of the received RLC PDUs (Packet Data Units) and receives an unreceived RLC. Check for the existence of PDUs. Upon receiving the packet containing the 'last packet indicator', the RLC status report 885 including the reception status information of the RLC PDUs is transmitted through the uplink channel. If the UE has received all of the RLC PDU [x] to RLC PDU [x + n], the RLC status report receives an Ack signal for the RLC PDUs, and the UE receives the corresponding activation period. Upon completion of the transmission of the RLC status report that acknowledges all packets positively, the activation period ends.

If the UE has not received any of the RLC PDUs [x + m] among the RLC PDUs [x] to RLC PDUs [x + n], the UE negatively acknowledges the unreceived RLC PDUs in the RLC status report. Include the (Nack) signal. As such, when the status report includes a negative acknowledgment signal, the UE maintains an activation period until retransmission of the negatively recognized RLC PDU is completed.

9 is a block diagram illustrating a terminal receiving apparatus according to a fourth embodiment of the present invention.

The terminal may be configured with a plurality of RLC entities 935, 940, and 945 implemented for each application, and a specific RLC entity may be configured to operate in a discontinuous reception mode.

In FIG. 9, for example, the RLC entity at 945 is an RLC entity operating in discontinuous reception mode.

The RLC entity 945 operating in the discontinuous mode requests the DRX controller 925 to end the activation period when all of the following conditions are met.

Receive the RLC PDU containing the last packet indicator

-Successfully received all packets received during the activation period

-Complete transmission of the RLC status report containing the positive acknowledgment signal for all packets received during the activation period

In addition, as described above, the RLC entity 945 checks the serial numbers of the RLC PDUs to check whether there are any unreceived packets, and configures an RLC status report according to the check.

When the DRX controller 925 receives a signal from the RLC entity 945 operating in the discontinuous mode that the activation period has ended, the DRX controller 925 ends the activation period and remains in a sleep state until the next activation period begins.

The demultiplexing / multiplexing apparatus 905 of the UE multiplexes RLC PDUs transmitted from the RLC layer, that is, the RLC entities 935, 940, and 945 into MAC PDUs, or MAC PDUs transmitted from the HARQ processor 915 into the RLC PDUs. Demultiplex and forward to the appropriate RLC entities 935, 940, 945.

The HARQ processor 915 processes the HARQ packet received by the transceiver 930 through a predetermined HARQ operation, transmits an error-free HARQ packet to the demultiplexing / multiplexing apparatus 905, and receives the HARQ packet. The demultiplexing block of the multiplexing / multiplexing apparatus 905 transmits the HARQ packet to the RLC layer 935, 940, 945.

In addition, the HARQ processor 915 transmits the MAC PDU received from the multiplexing block of the demultiplexing / multiplexing apparatus 905 to the transceiver 930 through a predetermined HARQ operation, and the transceiver 930 transmits the MAC PDU to the base station. To send.

The control channel processing unit 920 processes the information received through the forward common control channel, and reports any packet transmitted to the corresponding terminal to the DRX control unit 925.

The DRX control unit 925 recognizes the start time of the activation period and turns on the receiver at the start time. If the terminal does not receive a report from the control channel processor 920 that the packet is transmitted to the terminal until the minimum activation period expires, the activation period ends. On the other hand, upon receiving a report from the control channel processor 920 that there is a packet transmitted to the terminal, the activation period is maintained until a signal indicating that the activation period has ended from the RLC entity 945.

10 is a flowchart illustrating a terminal operation according to a fourth embodiment of the present invention.

First, in step 1005, the UE prior to DRX operation, DRX cycle length (DRX cycle length), information that can induce the starting position (starting position) of the activation period, call setting the minimum active period length (minimum active period length), etc. Receives through the process of.

In step 1010, the terminal derives the starting point of the activation period by using a predetermined rule, using the information to derive the starting point of the activation period, and checks whether it is the start point of the current activation period. If the check result of step 1010 is not the start point of the current activation period, the terminal proceeds to step 1035 until the start point of the activation period to maintain the sleep period, if the start point of the activation period proceeds to step 1015. The UE derives the initial activation period start time in a predetermined manner, and once the start point of the activation period is recognized, the subsequent activation period starts at a point away from the start point of the previous activation period by DRX cycle length.

In operation 1015, the terminal drives the timers T (DRX_CYCLE_LENGTH) and T (MINIMUM_ACTIVE).

T (DRX_CYCLE_LENGTH) is a timer in which the DRX cycle length recognized in step 1005 is input, and T (MINIMUM_ACTIVE) is a timer in which the minimum activation period recognized in step 1005 is input.

In step 1020, the UE monitors whether there is a packet to be received through the common control channel. If there is no packet transmitted to the terminal until T (MINIMUM_ACTIVE) expires, that is, until the minimum activation period ends in step 1020, the terminal branches to step 1035, enters the sleep mode, and the next activation period begins. Stay in sleep until The start of the next activation period is when T (DRX_CYCLE_LENGTH) driven in step 1015 expires.

On the contrary, if there is a packet transmitted to the user before the minimum activation period ends in step 1020, the terminal proceeds to step 1025 and receives the packet according to a normal HARQ operation.

If the packet is successfully received in step 1025, the terminal checks whether the packet received in step 1030 is the last packet. Whether or not the last packet can be confirmed through, for example, control information piggybacked on the received RLC PDU. The RLC sender transmits the last RLC PDU while including the control information that the RLC PDU is the last RLC PDU in the last RLC PDU. In step 1030, the RLC receiving side checks whether the received RLC PDU includes control information indicating that it is the last RLC PDU.

If it is not possible to receive a packet including control information of the last packet in step 1030, the terminal proceeds to step 1025 and performs a packet receiving process until receiving a packet including control information of the last packet.

On the other hand, when receiving the packet including the control information of the last packet in step 1030, the UE proceeds to step 1040 and configures the RLC status report (RLC status report) containing the RLC PDU reception status information up to the point in time. The RLC status report includes the RLC serial number of the unreceived packet and the RLC serial number of the received packet. As described above, the RLC serial number of the unreceived packet is called NACK, and the RLC serial number of the received packet is called ACK. That is, the RLC status report includes NACK information and ACK information. The NACK information is a set of serial numbers of unreceived packets, and the ACK information is a set of serial numbers of the received packet.

In step 1045, if the NLC is not included in the RLC status report of step 1040, the UE checks whether the ACK for all RLC PDUs including the last RLC PDU having a serial number lower than the last RLC PDU is included. If the check result is true, it means that the last RLC PDU is well received and there is no packet to retransmit, and the process proceeds to step 1050. If the check result is false, it means that there is a packet that needs to be retransmitted, and the process proceeds to step 1055.

After transmitting the RLC status report in step 1050, the terminal proceeds to step 1035 and enters the sleep mode until the next activation period begins. The start of the next activation period is when the timer T (DRX_CYCLE_LENGTH) driven in step 1015 expires.

In step 1055, the UE transmits the RLC status report and waits for retransmission of RLC packets requesting retransmission in the RLC status report to be completed. After retransmission of the RLC packets is completed, an RLC status report containing ACK signals for all RLC PDUs having a serial number lower than the last RLC PDU is transmitted, and the process proceeds to step 1035 until the next activation period begins. Enter sleep mode.

As described above, according to the present invention, the length of the activation period may be adjusted according to the traffic requirement at the time of reception in a packet service in which the traffic occurrence situation may vary every discontinuous reception period.

Claims (13)

In the method for the UE performs a discontinuous reception (DRX) operation in a mobile communication system, Starting a first timer for monitoring control data over a common control channel; Starting or restarting a second timer for monitoring the control data when the control data indicating a new transmission of related user data is received through the common control channel. Way. The method of claim 1, wherein the duration value of the first timer and the duration value of the second timer are received from a base station. The method of claim 1, And receiving the start information from the base station to determine the start time of the first timer. The method of claim 1, And monitoring the control data through the common control channel during the operation of the first timer and the second timer. The method of claim 1, The terminal further comprises stopping at least one of the first timer and the second timer when receiving a control signal indicating that at least one of the first timer and the second timer is stopped. How to do it. The method of claim 1, The common control channel includes a physical downlink control channel (Physical Downlink control channel PDCCH), characterized in that the terminal performs a discontinuous reception operation. An apparatus for performing a discontinuous reception (DRX) operation in a terminal of a mobile communication system, A first timer for monitoring control data over a common control channel, and a second for monitoring the control data when the control data instructing a new transmission of associated user data is received over the common control channel. Apparatus for performing a discontinuous reception operation in the terminal including a DRX control unit for starting or restarting the timer. The method of claim 7, wherein the DRX control unit, And a duration value of the first timer and a duration value of the second timer are received from a base station. The method of claim 7, wherein the DRX control unit, And receiving start information from a base station to determine a start time of the first timer. The method of claim 7, wherein the DRX control unit, And monitoring the control data through the common control channel during the operation of the first timer and the second timer. The method of claim 7, wherein the DRX control unit, When receiving a control signal indicating that at least one of the first timer and the second timer is stopped, at least one of the first timer and the second timer is interrupted, the terminal performs a discontinuous reception operation Device. The method of claim 7, wherein The common control channel is a device for performing a discontinuous reception operation in the terminal characterized in that it comprises a physical downlink control channel (PDCCH). delete

Images