KR20090068880A - Method and apparatus for transmitting and receiving packets in a mobile communication system using hybrid auto repeat request - Google Patents

Abstract

A method and an apparatus for reducing a system information delay are provided to prevent execution of an unnecessary HARQ(Hybrid Auto Repeat Request) process in a terminal by defining a HBFI(HARQ Buffer Flush Indicator) field to control information. A terminal receives a packet through an allocated fixing resource(601). The terminal performs decoding about the received packet(603). An ACK is fed back in a decoding success state(613). An NACK is fed back. A packet having a CRC error is stored in a buffer(605). The terminal receives control information(607). The terminal confirms activation of a HBFI field data(609). The terminal discards a packet stored in the buffer in an activated state of the HBFI field data. The terminal handles a packet transmitted from a base station as an initial packet(611). The terminal handles a packet transmitted from the base station as a retransmission in a stand-by state of the HBFI field data(615).

Description

METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING PACKETS IN A MOBILE COMMUNICATION SYSTEM USING HYBRID AUTO REPEAT REQUEST}

The present invention relates to packet retransmission in a mobile communication system. More particularly, the present invention relates to an apparatus and a method for transmitting a packet in a mobile communication system using a hybrid auto repeat request (HARQ).

The next generation mobile communication system has been developed to provide a high-speed mass communication service to a mobile station (hereinafter referred to as "MS"). A representative example of the next generation mobile communication system is Long Term Evolution (LTE). The 3rd Generation Partnership Project (3GPP), which is currently in charge of LTE standardization, is discussing Long Term Evolution (LTE), a next-generation mobile communication system based on Universal Mobile Telecommunication Service (UMTS). LTE is a technology that implements high-speed packet-based communication of about 100 Mbps, aiming for commercialization in 2010. For convenience of explanation, LTE will be described below as an example of a mobile communication system. Hereinafter, the technology applied to the LTE will be briefly described.

The technique used in LTE uses Orthogonal Frequency Division Multiplexing (OFDM) as a modulation scheme, and as an error control scheme. Hybrid Automatic Repeat Request (HARQ) is used.

The OFDM is a method of transmitting data using a multi-carrier, that is, a multi-carrier, and a plurality of multi-carriers having a parallel symbol string input in parallel and having each orthogonal relationship therebetween. That is, it is a kind of multi-carrier modulation that modulates and transmits a plurality of sub-carrier channels. In the OFDM scheme, a modulated signal is located in a two-dimensional resource composed of time and frequency. The resources on the time axis are divided into different OFDM symbols and they are orthogonal to each other. The resources on the frequency axis are divided into different tones and they are also orthogonal to each other. That is, in the OFDM scheme, if a specific OFDM symbol is designated on the time axis and a specific tone is designated on the frequency axis, it may indicate one minimum unit resource. This is called a resource block (hereinafter, referred to as 'RB').

HARQ is a combination of Forward Error Correction (FEC) and ARQ (Automatic Repeat reQuest) methods, which are representative transmission error control techniques used in packet data communication systems. It is known that it can. When the sender sends a packet to the receiver, the receiver attempts error correction on the transmitted packet and determines whether to request retransmission of the transmitted packet using a simple error detection code such as a cyclic redundancy check (CRC). That is, the receiving side feeds back an ACK signal to the transmitting side if an error does not exist in the received packet, and feeds back a NACK signal if an error exists. On the other hand, the transmitting side transmits the next packet in response to the ACK, and retransmits the packet in error in response to the NACK signal. After that, the receiver stores the packet in error and increases the reception rate of the packet by using a data combining method called soft combining with the retransmitted packets. In the following description, the first transmission of a packet to a reception side is defined as 'initial transmission' and the transmission of the packet by NACK feedback for the initial transmission is defined as 'retransmission'.

Hereinafter, a method of allocating an RB between terminals by a base station will be described. The base station transmits control information including resource allocation information, which is information about the RB, to the terminal through the control channel in order to transmit and receive data with the terminal. The transmission period of the control information is usually a frame period.

However, a packet generated periodically to the terminal (for example, Voice over Internet Protocol (VoIP), for example, VoIP packets have a characteristic that a packet having a constant size of about 40 bytes is periodically generated every 20ms) In this case, transmitting the resource allocation information every frame in order for the base station to transmit the resource allocation information on the resource allocated to the corresponding terminal may cause unnecessary resource waste.

Therefore, when the base station provides a periodic packet (hereinafter, referred to as a "cyclic packet") service to the terminal, it is desirable to allocate resources to the terminal fixedly. In this way, a resource that is fixedly allocated to a specific terminal is a resource. When the terminal is allocated a fixed resource from the base station, it is possible to use the fixed resource at regular times without receiving resource allocation information every frame. Of course, when the resource allocation to the terminal is changed or the resource allocation is released, the base station may notify the terminal of the resource allocation change and resource allocation release using separate resource allocation information. As a result, when the fixed resource is used, it is not necessary to transmit resource allocation information every frame, thereby reducing waste of resources by the resource allocation information. In contrast, the dynamic resource refers to a resource allocated by the base station to the terminal aperiodically. In this case, resource allocation information should be transmitted to the terminal before allocating dynamic resources.

Hereinafter, a packet generated for the periodic packet service is defined as a 'cyclic packet'. If the periodic packet fails to be retransmitted and is retransmitted, it is not periodically generated. However, since the initially transmitted packet is a periodic packet, the packet used for retransmission also corresponds to a periodic packet. For example, the VoIP packet initially transmitted is not only a periodic packet, but also a VoIP packet retransmitted is a periodic packet. In contrast, packets that are not used for periodic packet service are defined as 'aperiodic packet'.

In the current LTE system, in the VoIP packet transmission, a fixed resource scheme is used for initial transmission and a dynamic resource scheme is used for retransmission. Since the VoIP packet is periodically transmitted, the fixed resource method is used for the initial transmission. Since the retransmission occurs aperiodically, the dynamic resource method is used for the retransmission.

1 is a conceptual diagram illustrating a resource allocation method in a mobile communication system. For the sake of understanding, it is assumed that the ACK is fed back after the packet is initially transmitted or retransmitted, except when the NACK is fed back in the following drawings. However, the feedback ACK will not be shown. This may be confused with the illustrated NACK. However, it should be noted that if necessary for the understanding, the ACK will be recalled.

In FIG. 1, through the dynamic resources 111, 113, and 115 for VoIP packets initially transmitted from the base station to the terminal through the fixed resources 101, 103, 105, and 107 and the NACKs 121, 123, and 125 of the terminal. Packets retransmitted from the base station to the terminal are shown. In addition, it can be seen that control information including resource allocation information for the dynamic resources 111, 113, and 115 is transmitted through the control channels 131, 133, and 135 before the retransmission.

However, using the fixed resource method for the initial transmission of VoIP may cause the following problems.

The first problem arises when fixed resources allocated to VoIP are used to transmit other data with higher priority than VoIP packets. A representative example of data that has higher priority than VoIP packets is system information. Depending on the system, data having a higher priority than the VoIP packet may be set in addition to the system information. For convenience of explanation, hereinafter, the first problem will be described using, as system information, data having a higher priority than the VoIP packet. In addition, the first problem is defined as 'system information delay'. The system information delay will be described in detail below.

The terminal receives system information from the base station. The system information refers to general information necessary for performing communication between the base station and the terminal. In general, the terminal receives system information from the base station before transmitting and receiving application data between the terminal and the base station. Therefore, system information has higher priority than application data. Therefore, the terminal receiving the VoIP service does not need to receive system information from the base station any more unless there is a special situation since the system information is received from the base station before the VoIP packet transmission and reception.

However, when a fixed resource is allocated to a corresponding terminal and a VoIP packet is transmitted and received, the corresponding base station may transmit system information to another terminal. In this case, when there is not enough RB to be used by the base station to transmit system information, the allocated fixed resource may be used to transmit system information. That is, fixed resources allocated to one terminal for VoIP packets may be used for other purposes. In this case, the allocated fixed resource is not used for VoIP packet transmission, causing transmission delay. This example is shown in FIG. 2 below.

2 is a conceptual diagram illustrating a system information delay occurring in a conventional mobile communication system. The first VoIP packet was initially transmitted through the fixed resource 201. The ACK was fed back because there was no error in the first packet. The system information was then transmitted through the fixed resource 203. However, the terminal does not know whether the packet transmitted through the fixed resource 203 is a system information packet. Therefore, it is recognized as a VoIP packet and error checking is performed. Since it is not a VoIP packet, an error is detected. Therefore, the system information packet in which an error is detected is stored in a buffer, and the NACK 211 is fed back to request retransmission. Since the base station receives the ACK for the first packet, the base station initially transmits the second VoIP packet through the fixed resource 205. The terminal soft combines the system information packet 203 stored in the buffer and the VoIP packet 205 received after the retransmission request. However, since both are not the same VoIP packet, an error occurs. Therefore, the NACK 213 is fed back to request retransmission. The base station retransmitted the second VoIP packet through the dynamic resource 215 for the NACK 213. As described above, a time delay 221 occurs when the terminal recognizes the system information packet 203 as a VoIP packet and requests retransmission.

The second problem is caused by jitter delay. This is illustrated in FIG. 3 below.

3 is a conceptual diagram illustrating jitter delay occurring in a conventional mobile communication system. The jitter delay is a transmission delay caused by an increase in delay time due to some cause in the core network connected to the base station and the VoIP packet reaching the base station late, and thus the VoIP packet cannot be transmitted through the originally allocated fixed resource. At this time, a packet transmitted through the fixed resource is called a null packet. In FIG. 3, the first VoIP packet is transmitted through the fixed resource 301. The ACK was fed back because there was no error in the packet. The second VoIP packet has to be transmitted through the fixed resource 303, but reaches the base station after the time allocated to the fixed resource 303 according to the transmission delay in the core network (331). Therefore, the second VoIP packet cannot be transmitted through the fixed resource 303. In this case, the terminal also performs an error check on the fixed resource 303. Since the fixed resource 303 includes a null packet, a CRC check is performed for this, and the terminal feeds back the NACK 321. The second, late arriving VoIP packet is initially sent over the fixed resource 305. However, the terminal recognizes this as a retransmission to the NACK 321 and soft combines the null packet. Naturally, since an error occurs, the UE feeds back the NACK 323 again. The base station retransmits the second VoIP packet to the NACK 323 through the dynamic resource 311. In other words, the transmission delay 333 occurs because fixed resources are not used in the VoIP packet due to the jitter delay.

Generalizing the problems of system information delay and jitter delay described with reference to FIGS. 2 and 3 are as follows. That is, the fixed resource allocated to the terminal for the periodic packet service should be used for the transmission of the periodic packet. In some cases, however, when the fixed resource transmits an aperiodic packet (the system information packet or a null packet is an example), the terminal recognizes the packet included in the fixed resource as a packet transmitted to the fixed resource. Performs HARQ on the packet included in the.

In this case, an error inevitably occurs during decoding, thereby storing the packet in error and requesting a packet retransmission to the base station. Then, the base station recognizes the periodic packet actually transmitted initially as a retransmitted periodic packet and performs soft combining. This also inevitably generates a CRC error. This process causes a transmission delay.

In order to solve the above problem, the present invention provides a method and apparatus for reducing system information delay occurring during transmission of a periodic packet.

The present invention also provides a method and apparatus for reducing jitter delay that occurs during the transmission of periodic packets.

The present invention also provides a method and apparatus for reducing transmission delay due to idle fixed resources caused by some cause during the transmission of a periodic packet.

Therefore, the method for transmitting a packet to the terminal by the base station provided by the present invention,

Allocating fixed resources to provide a periodic packet service to a terminal;

After providing the aperiodic packet through the fixed resource while providing the periodic packet service, an active buffer empty indicator (HARQ Buffer Flush Indicator (HBFI)) field and dynamic resource information are included.

Method for receiving a packet from a base station by a terminal provided by the present invention,

Receiving a fixed resource from the base station to receive a periodic packet service;

Receiving and decoding a packet through the fixed resource, storing a packet in which a decoding result error occurs in a buffer, and feeding back a NACK to the base station;

Discarding a packet stored in the buffer according to the activated HBFI field when receiving control information including an activated HBFI field and dynamic resource information indicating to discard the packet stored in the buffer. .

The base station provided by the present invention transmits a packet to a terminal,

Allocating fixed resources to provide a periodic packet service to a terminal;

Transmitting control information to the terminal, the control information including an activated HBFI field instructing the terminal to ignore the fixed resource, if the terminal intends to transmit the aperiodic packet through the fixed resource;

Transmitting control information including dynamic resource information to be used for transmission of the periodic packet after the packet is transmitted, to the terminal;

And transmitting the periodic packet to the terminal by using the dynamic resource indicated by the dynamic resource information.

Method for receiving a packet from a base station by a terminal provided by the present invention,

Allocating fixed resources from the base station to receive periodic packet services;

Receiving control information from the base station, the control information including an activated HBFI field instructing the terminal to ignore a fixed resource while receiving the periodic packet service;

Ignoring the packet transmitted through the fixed resource according to the indication of the activated HBFI field, and receiving control information including dynamic resource information to be used for transmission of the periodic packet from the base station.

An apparatus for receiving a packet from a base station by a terminal provided by the present invention,

A transceiver for receiving a packet and control information through a fixed resource allocated in advance to receive a periodic packet service;

An HARQ processor performing an HARQ operation on the received packet;

A control channel processor for checking the HBFI field and dynamic resource information included in the received control information;

And a controller for controlling the HARQ processor according to the identified HBFI field and receiving the periodic packet using the dynamic resource according to the identified dynamic resource information.

The effect by the present invention is as follows.

According to the present invention, by defining an HBFI field in control information, an unnecessary HARQ process is not performed in a terminal, thereby reducing transmission delay caused by a fixed resource transmitting an aperiodic packet. In addition, in defining the HBFI field, by using the NDI field of the existing control information, transmission delay due to an aperiodic packet can be reduced without using additional resources. In addition, it is possible to reduce the transmission delay by transmitting periodic packets not transmitted by the fixed resource through the dynamic resource.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. 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. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

Embodiments proposed by the present invention can be applied in any communication system using HARQ. In the following description, however, the base station will be described as a transmitting side and a terminal as a receiving side. In addition, the system information delay will be described as an example of a delay caused by an aperiodic packet. Since the system information is data transmitted from the base station to the terminal, the system information delay occurs mainly when the base station is the transmitting side. If the terminal is the transmitting side, system information delay may not occur. However, since the aperiodic packet may be transmitted due to some cause, the embodiment of the present invention may be applied even when the terminal is the transmitting side.

In the present invention, a field called HARQ Buffer Flush Indicator (HBFI) is newly defined in control information transmitted from the base station to the terminal. The HBFI field may consist of 1 bit. In addition, when the initially transmitted packet is transmitted to the fixed resource but NACK is feedback, this field is used to control the HARQ buffer. The present invention consists of two embodiments, in which the HBFI enabled (ie, HBFI = 1) state in the first embodiment indicates that the packet stored in the buffer is an invalid packet and therefore discarded. On the contrary, the deactivation state of HBFI (HBFI = 0) means to perform normal HARQ. In other words, since the packet stored in the buffer is a valid packet, it means to perform soft combining with the currently retransmitted packet. In the second embodiment, the meaning of the HBFI field will be described later. Based on the HBFI field defined in the present invention, the method according to the first embodiment of the present invention will be described below in FIGS. 4 to 7.

4 is a conceptual diagram illustrating a packet transmission and reception method in a mobile communication system according to a first embodiment of the present invention.

If the base station allocates a fixed resource to the terminal for transmitting the VoIP packet to the terminal and provides the VoIP service to the terminal, if there is no transmission resource when the base station attempts to transmit a system information packet to another terminal, the base station temporarily A system information packet is transmitted using the fixed resource (401). The terminal recognizes this as a VoIP packet transmitted to it and receives it. The terminal decodes the received packet, recognizes that an error has occurred in the packet through CRC check, stores it in a buffer, and transmits a NACK signal to the base station (403). The base station transmits control information in which the HBFI field is activated (HBFI = 1) to inform that the packet received by the terminal is not a VoIP packet transmitted to the terminal (405). The control information also includes dynamic resource information to be used for transmission of the VoIP packet. After checking the HBFI value, the terminal recognizes that the transmitted packet is not a VoIP packet delivered to the terminal and discards the packet stored in the buffer. Thereafter, the base station transmits the VoIP packet through the dynamic resource (420).

5 is a signaling flowchart illustrating a packet transmission and reception method in a mobile communication system according to a first embodiment of the present invention.

In step 501, the base station 530 allocates a fixed resource to the terminal 520 to transmit the VoIP packet. The VoIP packet is transmitted using the fixed resource allocated in step 503. In step 505, the base station 530 uses the allocated fixed resource to transmit the system information packet to other allocated terminals. At this time, since the terminal 520 recognizes the system information packet as a VoIP packet and performs the HARQ process, an error occurs and stores the packet in which the error occurs in a buffer. In step 507, the base station transmits control information including the activated HBFI field to the terminal 520 through a control channel. In step 509, the terminal 520 empties the buffer by checking the HBFI field and recognizing that the packet stored in the buffer is invalid. In step 511, the base station 530 transmits the VoIP packet again.

6 is a flowchart illustrating a packet transmission and reception method in a mobile communication system according to a first embodiment of the present invention.

In step 601, the terminal receives a packet through the allocated fixed resources. In step 603, the UE decodes the received packet, and if successful, proceeds to step 613 to feed back an ACK, and if failed, proceeds to step 605. In step 605, the NACK is fed back and a packet in which a CRC error occurs is stored in a buffer. In step 607, the terminal receives the control information. This is because the base station transmits the information on the dynamic resource to the terminal because the base station transmits a packet through the dynamic resource for the NACK. In step 609, the UE checks whether the HBFI field value is activated and proceeds to step 611 if the activation state (that is, HBFI = 1), and proceeds to step 615 if the inactive state (HBFI = 0). In step 611, the terminal discards the packet stored in the buffer and treats the packet transmitted by the base station as the initially transmitted packet. In step 615, the terminal treats the packet transmitted by the base station as a retransmission and receives it. That is, decoding is performed by soft combining the packets stored in the buffer and the packets received by retransmission.

In the first embodiment described so far, the HBFI field may be set in addition to the conventional control information. However, in this case, the amount of control information to be transmitted through the control channel increases. Therefore, a method of dedicating a field used in conventional control information without using additional resources can be considered. For this purpose, it is not used in the situation where the HBFI field is used among the fields of the conventional control information, and a size similar to the HBFI field should be found. One of the fields of the conventional control information corresponds to the NDI (New Data Indicator) field. The NDI field is not used for retransmission of a packet initially transmitted through the fixed resource, and its size is 1 bit and is the same as the HBFI field. Therefore, the NDI field may be used as the HBFI field. Hereinafter, a method of using the HBFI field exclusively for the conventional NDI field will be described.

7 is an exemplary view illustrating a method of transmitting a packet when using a conventional NDI field and an HBFI field of the present invention.

(a) describes how the NDI field is used. The existing NDI field is control information having a size of 1 bit. As the name (New Data Indicator) implies, the NDI field indicates whether a transmitted packet is a new packet. In addition, the NDI field is used when an initially transmitted packet is transmitted through a dynamic resource. In (a), when the first packet 701 is initially transmitted through the dynamic resource, control information is transmitted first. In this case, the NDI value included in the control information is 0 (705). If an error occurs in the initial transmission and packet 1701 is retransmitted, NDI = 0 (707, 709) is maintained until transmission without error. This is because NDI is defined to maintain the same value whenever the same packet is transmitted regardless of retransmission. If packet 1701 succeeds in transmission, packet 2703 should be transmitted. At this time, the NDI value is 1 regardless of whether the second packet is the initial transmission 711 or the retransmission 713, 714. If packet 3 (not shown) is transmitted, the NDI value is zero again. That is, when a new packet is transmitted through the dynamic resource, the NDI field can distinguish the packet from the packet by toggling its value. The reasons why NDI is used for dynamic resources are as follows. That is, since fixed resources are allocated periodically, the UE can know that a new packet is transmitted even without NDI.

(b) describes how the HBFI field is used. The HBFI field is used when performing control on a packet initially transmitted through a fixed resource. The fixed resources allocated in (b) are 725 and 731. If packet 1721 is transmitted using a fixed resource but an error occurs, retransmission of packet 1 is performed. For reference, since the fixed resource does not require separate control information, control information was not transmitted prior to initial transmission (725). An error occurred in the initial transmission and packet 1 must be retransmitted. Since retransmission uses dynamic resources, control information is transmitted before retransmission. At this time, the control information includes the HBFI field. It is assumed that packet 1 is transmitted without error through two retransmissions 727 and 729, and HBFI = 0 is set. HBFI = 0 means that the packet stored in the buffer is a valid packet, so soft combining with the currently retransmitted packet is required.

Suppose that the base station uses the fixed resource 731 allocated to the terminal for transmission of system information. At this time, the control information is not transmitted (731). However, the terminal determines that the transmitted system information packet is transmitted to itself and performs an error check. Of course, an error occurs, so we store it in a buffer and feed back a NACK to request retransmission. Thereafter, the base station transmits packet 2 through the dynamic resource 733. If you wait for the next fixed resource, the delay will be longer. Packet 2 transmitted at this time is substantially the initial transmission. However, since the UE has fed back the NACK for the system information packet, it will recognize this as retransmission. To prevent this, the base station transmits control information in which the HBFI value is set to 1 prior to the initial transmission of packet 2 (733). HBFI = 1 indicates that the packet stored in the buffer is an invalid packet and should be discarded. If an error occurs in the packet 2 initially transmitted, the UE will store it in a buffer and feed back a NACK. Accordingly, the base station transmits control information in which the HBFI value is set to 0 before retransmitting packet 2 through the dynamic resource (735). According to the HBFI value (= 0), the terminal performs soft combining on the second transmitted packet and the retransmitted packet.

Comparing the above-described NDI field and HBFI field is as follows. The NDI field is used when the initially transmitted packet is transmitted through dynamic resources. In addition, the value is maintained as long as the same packet is transmitted regardless of initial transmission or retransmission, and the value is toggled every time a new packet is changed and transmitted.

The HBFI field is used for HARQ control when the initially transmitted packet uses a fixed resource. If the value is 0, the packet stored in the buffer is a valid packet. If the value is 1, the packet stored in the buffer is an invalid packet, and thus discarding.

Both the NDI field and the HBFI field are configured with 1 bit. Therefore, although the HBFI field proposed in the present invention may be newly added to the existing control information, the existing NDI field may be used. That is, the control information consisting of one bit may be interpreted as an NDI field if the initially transmitted packet uses dynamic resources, and may be interpreted as an HBFI field if the initial transmitted packet uses fixed resources. By using the same field, there is an advantage of controlling HARQ without additionally occupying resources.

8 to 10, a second embodiment of the present invention will be described. The second embodiment of the present invention is a method for allowing the terminal to recognize that the system information packet is not its own by transmitting control information including the activated HBFI field before transmission of the system information packet. That is, the HBFI field activated in the second embodiment means that the packet transmitted later through the fixed resource does not belong to the corresponding terminal and thus ignores the fixed resource. On the contrary, the deactivated HBFI field means that a packet transmitted through the fixed resource is received by the corresponding terminal since the packet is transmitted through the fixed resource.

For reference, the first embodiment is a method in which the base station notifies that the system information packet does not belong to the terminal after the terminal recognizes and receives the system information packet as its own to perform the HARQ process. Therefore, the second embodiment has the effect of reducing the overhead of the terminal by not performing the unnecessary HARQ process. However, the first embodiment has the advantage that the terminal performs unnecessary HARQ process, but does not transmit the control information prior to the transmission of the system information packet, thereby using less communication resources. Hereinafter, the second embodiment will be described in detail.

8 is a conceptual diagram illustrating a packet transmission and reception method in a mobile communication system according to a second embodiment of the present invention.

When the base station intends to transmit a system information packet using the fixed resource while the VoIP packet is being transmitted through the fixed resource allocated to the terminal, the base station transmits control information 801 including the activated HBFI field to the terminal. . Then, when the base station transmits the system information packet 803 through the fixed resource, the terminal recognizes that the system information packet 803 is not its own by the activated HBFI field and does not receive the system information packet 803. Do not. Thereafter, the base station uses dynamic resources to transmit the VoIP packet. Therefore, the control information 805 for dynamic resource allocation is transmitted and the VoIP packet 807 is initially transmitted using the allocated dynamic resource. Thereafter, normal packet transmission is performed. In FIG. 8, it is assumed that an error occurs in the VoIP packet using the dynamic resource, the NACK 809 is fed back, and the decoding succeeds after retransmitting through the dynamic resource.

9 is a signaling flowchart illustrating a method for controlling HARQ between a base station and a terminal according to a second embodiment of the present invention.

In step 901, the base station allocates a fixed resource to the terminal. In step 903, the VoIP packet is transmitted using the fixed resource allocated. In step 905, the base station transmits control information including the activated HBFI field, and in step 905, the system information packet is transmitted using a fixed resource. At this time, the terminal does not receive the system information transmitted through the fixed resource. In step 909, the base station transmits control information for dynamic resource allocation and in step 911 transmits a VoIP packet using the allocated dynamic resource.

10 is a flowchart illustrating a packet receiving method of a terminal according to an HARQ control method according to a first embodiment of the present invention.

In step 1001, the terminal receives the control information transmitted by the base station. The control information received in step 1003 checks whether the HBFI field is activated and proceeds to step 1005 if it is activated and proceeds to step 1011 if it is inactive. In step 1011, the UE receives a packet transmitted through a fixed resource and proceeds to step 1009. In step 1009, the UE decodes the received packet and then performs a normal HARQ process.

In step 1005, since the UE checks the activated HBFI field, the UE recognizes that the packet transmitted through the fixed resource is not its own and ignores the fixed resource. That is, it does not receive a packet transmitted through a fixed resource and waits for receiving separate control information. In step 1007, the terminal receives separate control information, checks dynamic resource information included in the separate control information, and receives a packet transmitted through the dynamic resource. In step 1009, the UE performs a typical HARQ process for the packet transmitted in step 1007. The second embodiment of the present invention has been described above. In the second embodiment, it is obvious that the HBFI field may use an NDI field in the same manner as described with reference to FIG. 7, and thus a detailed description thereof will be omitted.

Hereinafter, a HARQ device of a terminal in which the first and second embodiments operate.

11 is a block diagram illustrating an apparatus for receiving a packet from a base station by a terminal in a mobile communication system according to an embodiment of the present invention.

The transceiver 1105 transmits and receives data through a wireless channel under the control of the controller 1109. That is, data is transmitted and received through a transmission resource allocated by the controller. In addition, the received packet is transmitted to the HARQ processor 1103 and the control unit 1109, and the received control information is transmitted to the control channel processor 1107.

The control channel processor 1107 checks the control information transmitted by the base station using the control channel. The dynamic resource information included in the control information is transmitted to the controller 1109. In addition, the HBFI field activation state of the control information is examined and the test result is transmitted to the controller 1109.

The HARQ processor 1103 receives the packet received by the transceiver 1105 to perform a normal HARQ process, and operates according to the embodiments proposed by the present invention. That is, the controller 1109 discards the packet stored in the buffer or soft combines the packet stored in the buffer and the retransmitted packet according to the HBFI field value transmitted from the controller 1109. That is, if the HBFI field is activated, the packet stored in the buffer inside the HARQ processor 1103 is discarded. If the HBFI field is not activated, soft combining is performed.

The controller 1325 determines a transmission resource to be used for data transmission and reception and transmits it to the transceiver 1105. In the case of using a fixed resource, the control unit 1325 transmits pre-allocated fixed resource information to the transceiver unit 1105. In the case of using a dynamic resource, the dynamic resource information received from the control channel processor 1107 is transmitted to the transceiver unit 1105. The dynamic resource is used for retransmission of a packet according to a general HARQ process, or as described in the first and second embodiments, after the base station transmits a system information packet through a fixed resource allocated to the terminal, the terminal is again transmitted. Used to send VoIP packets. In addition, the controller 1109 controls the HARQ process according to the first and second embodiments by transmitting the HBFI field information received from the control channel processor 1107 to the HARQ processor 1103.

The multiplexing and demultiplexing apparatus 1101 multiplexes packets generated in an upper layer into one transport block (TB) and delivers them to the HARQ processor 1103, and demultiplexes the TB received from the HARQ processor 1103. Pass it to the appropriate upper layer.

The first and second embodiments described so far have been used to solve the problem when the fixed resource allocated to the terminal is used for system information as described in FIG. However, the first and second embodiments may be applied in the same manner to solve the problem of jitter delay described in FIG. 3. That is, since the terminal recognizes the fixed resource that does not include the VoIP packet as a packet to be received by the jitter transmission delay, the terminal performs the HARQ operation, thereby causing the same problem as the system information transmission delay. It will be apparent to those skilled in the art that the embodiments of the present invention using the HBFI field operate equally with respect to the jitter delay, and thus the detailed description thereof is omitted.

1 is a conceptual diagram illustrating a resource allocation method in a mobile communication system;

2 is a conceptual diagram illustrating a system information delay occurring in a conventional mobile communication system;

3 is a conceptual diagram illustrating jitter delay occurring in a conventional mobile communication system;

4 is a conceptual diagram illustrating a packet transmission and reception method in a mobile communication system according to a first embodiment of the present invention;

5 is a signaling flowchart illustrating a packet transmission and reception method in a mobile communication system according to a first embodiment of the present invention;

6 is a flowchart illustrating a packet transmission / reception method in a mobile communication system according to a first embodiment of the present invention;

7 is an exemplary diagram illustrating a method of transmitting a packet when using a conventional NDI field and an HBFI field of the present invention.

8 is a conceptual diagram illustrating a packet transmission and reception method in a mobile communication system according to a second embodiment of the present invention;

9 is a signaling flowchart illustrating a HARQ control method between a base station and a terminal according to a second embodiment of the present invention;

10 is a flowchart illustrating a packet receiving method of a terminal according to an HARQ control method according to a first embodiment of the present invention;

11 is a block diagram illustrating an apparatus for receiving a packet from a base station by a terminal in a mobile communication system according to an embodiment of the present invention.

Claims (15)

In the method of transmitting a packet to a terminal by a base station of a mobile communication system, Allocating fixed resources to provide a periodic packet service to a terminal; After transmitting the aperiodic packet through the fixed resource while providing the periodic packet service, the UE transmits control information including an HARQ Buffer Flush Indicator (HBFI) field and dynamic resource information to the terminal. The base station comprising a process for transmitting a packet to a terminal. The method of claim 1, And transmitting the periodic packet to the terminal through the dynamic resource indicated by the dynamic resource information. The method of claim 1, wherein the HBFI field, A method for transmitting a packet to a terminal by a base station using a new data indicator (NDI) used to control packets serviced by dynamic resources. In the method of receiving a packet from a base station of a mobile communication system, Receiving a fixed resource from the base station to receive a periodic packet service; Receiving and decoding a packet through the fixed resource, storing a packet in which a decoding result error occurs in a buffer, and feeding back a NACK to the base station; When receiving from the base station control information including a HARQ Buffer Flush Indicator (HBFI) field and dynamic resource information indicating to discard the packet stored in the buffer, the buffer according to the activated HBFI field A method for receiving a packet from a base station, the terminal comprising the step of discarding the packet stored in the. The method of claim 4, wherein And receiving the packet from the base station by receiving the periodic packet from the base station through the dynamic resource indicated by the dynamic resource information. The method of claim 4, wherein the HBFI field, A method for receiving a packet from a base station by a terminal using a new data indicator (NDI) used for control of packets serviced by dynamic resources. In the method of transmitting a packet to a terminal by a base station of a mobile communication system, Allocating fixed resources to provide a periodic packet service to a terminal; When the terminal wants to transmit the aperiodic packet through the fixed resource, the terminal includes control information including a HARQ Buffer Flush Indicator (HBFI) field instructing the terminal to ignore the fixed resource. Sending it to Transmitting control information including dynamic resource information to be used for transmission of the periodic packet after the packet is transmitted, to the terminal; And transmitting the periodic packet to the terminal by using the dynamic resource indicated by the dynamic resource information. The method of claim 7, wherein the HBFI field, A method for transmitting a packet to a terminal by a base station using a new data indicator (NDI) used to control packets serviced by dynamic resources. In the method of receiving a packet from a base station of a mobile communication system, Allocating fixed resources from the base station to receive periodic packet services; Receiving control information from the base station, the control information including an HARQ Buffer Flush Indicator (HBFI) field instructing the terminal to ignore a fixed resource while receiving the periodic packet service; The UE comprising the step of ignoring the packet transmitted through the fixed resource according to the indication of the activated HBFI field, and receiving control information from the base station, the control information including the dynamic resource information to be used for the transmission of the periodic packet from the base station How to receive a packet. The method of claim 9, And receiving the packet from the base station by receiving the periodic packet from the base station through the dynamic resource indicated by the dynamic resource information. The method of claim 9, wherein the HBFI field, A method for receiving a packet from a base station by a terminal using a new data indicator (NDI) used for control of packets serviced by dynamic resources. An apparatus for receiving a packet from a base station by a terminal of a mobile communication system, A transceiver for receiving a packet and control information through a fixed resource allocated in advance to receive a periodic packet service; An HARQ processor performing an HARQ operation on the received packet; A control channel processor for checking a HARQ Buffer Flush Indicator (HBFI) field and dynamic resource information included in the received control information; And a control unit for controlling a HARQ processor according to a state of the identified HBFI field and receiving a packet from a base station by a terminal for receiving the periodic packet using the dynamic resource according to the identified dynamic resource information. The method of claim 12, The HARQ processor is configured to decode the received packet, store a packet in which a decoding result error occurs in a buffer, and feed back a NACK to the base station, And the control unit is configured to discard a packet stored in the buffer when the HBFI field is in an activated state. The method of claim 12, wherein the control unit, And a terminal configured to not perform the HARQ operation on a packet received through the fixed resource when the HBFI field is activated. The method of claim 12, wherein the HBFI field, An apparatus for receiving a packet from a base station by a terminal using a new data indicator (NDI) used to control packets serviced by dynamic resources.

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