KR20070108801A - Apparatus and method of effective harq assisted arq operation for high rate data transmission - Google Patents

Abstract

An effective retransmission device and a method for high-speed data processing are provided to reduce load generated due to HARQ(Hybrid Automatic Retransmission Request) and ARQ operations by transmitting only local NACK(Negative Acknowledgement) through an HARQ transmitting part and ACK including the final sequence number of normally received packets, through an ARQ receiving part. A method for retransmitting high-speed packet data at a transmitter ARQ entity of a mobile communication system performing HARQ and ARQ at the same time includes the steps for receiving an ACK signal including the final sequence number of packets continuously and normally received from a receiver ARQ entity; receiving an NACK signal corresponding to ARQ packets(822,826) that are not normally received through HARQ, from a transmitter HARQ entity; and checking at least one ARQ packet that is not normally transmitted, in consideration of ACK and NACK and retransmitting a retransmission packet including the checked ARQ packets.

Description

Efficient retransmission apparatus and method for high speed data processing {APPARATUS AND METHOD OF EFFECTIVE HARQ ASSISTED ARQ OPERATION FOR HIGH RATE DATA TRANSMISSION}

1 is a diagram illustrating the structure and packet structure of a general radio protocol.

2 is a diagram illustrating the operation of a general HARQ.

3 is a diagram illustrating a problem when HARQ and ARQ operate independently according to the prior art;

4 is a diagram illustrating a problem when HARQ and ARQ operate in accordance with the prior art.

5 is a diagram illustrating an operation of detecting an HARQ NACK / ACK error according to the prior art;

6 is a diagram illustrating problems caused when driving HARQ and ARQ according to the prior art.

7 is a diagram illustrating an operation of interworking HARQ and ARQ according to the present invention.

8 illustrates generation of a local NACK in accordance with the present invention.

9 is a diagram illustrating the operation of the HARQ and ARQ layer for transmitting and receiving an ACK signal according to a first embodiment of the present invention.

10 is a diagram illustrating a format structure of an ACK signal according to a first embodiment of the present invention;

FIG. 11 is a signal flowchart illustrating a process of receiving, by a transmitting side, an ACK signal according to a first embodiment of the present invention. FIG.

12 is a diagram illustrating the operation of the HARQ and ARQ layer for transmitting and receiving an ACK signal according to a second embodiment of the present invention.

13 illustrates a format structure of an ACK signal according to a second embodiment of the present invention.

FIG. 14 is a signal flowchart illustrating a process of receiving, by a transmitting side, an ACK signal according to a second embodiment of the present invention. FIG.

15 is a view illustrating an operation in which HARQ and ARQ interoperate and prevent duplicate transmission according to the present invention.

16A to 16D illustrate a HARQ transmission state table for preventing duplicate transmission according to the present invention.

The present invention relates to a mobile communication system, and more particularly, to an efficient retransmission apparatus and method for processing high-speed data.

UMTS (Universal Mobile Telecommunication Service) system is based on the European mobile communication system Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), and Wideband Code Division Multiple Access: Third generation asynchronous mobile communication system using " CDMA. &Quot;

The 3rd Generation Partnership Project (3GPP), which is in charge of UMTS standardization, is discussing Long Term Evolution (LTE) as the next generation mobile communication system for UMTS systems. LTE is a technology that implements high-speed packet-based communication of about 100 Mbps, aiming for commercialization in 2010. To this end, various 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.

In such an LTE system, hybrid automatic retransmission (Hybrid ARQ (hereinafter referred to as HARQ)) is used to increase the transmission efficiency of a high-speed packet. The HARQ alone provides a variety of quality of service (QoS). Since it cannot satisfy the requirement of ',' a separate automatic retransmission (hereinafter referred to as 'ARQ') can be performed in the upper layer.

Here, HARQ is a technique of increasing the reception success rate by soft combining with retransmitted data without discarding previously received data. In more detail, the HARQ receiver determines whether there is an error in a received packet, and according to whether the error exists, an acknowledgment signal (hereinafter referred to as HARQ ACK) or a negative acknowledgment (Non-Acknowledged). In the following description, a " HARQ NACK " Therefore, the transmitter performs retransmission of the HARQ packet or transmission of a new HARQ packet according to the HARQ ACK / NACK signal. That is, the characteristic of HARQ is a technique of soft combining the retransmitted packet with the previously received packet to reduce the probability of error occurrence.

ARQ, on the other hand, is a technique for requesting retransmission for a packet not received by checking a serial number of a received packet, and does not perform soft combining operation on previously received packet and retransmitted packet. Since both ARQ and HARQ play a role of restoring a packet in error, it is not necessary to drive both together. However, since HARQ alone is difficult to obtain a sufficiently low packet error ratio, most packet services require both ARQ and HARQ to proceed simultaneously. This is because the HARQ ACK / NACK signal is a 1-bit response signal in HARQ, and it is difficult to reduce an error rate through channel coding, and thus, it is difficult to achieve a low packet error rate using only HARQ. . That is, if the HARQ NACK signal is incorrectly recognized as a HARQ ACK signal (hereinafter referred to as a HARQ NACK / ACK error), the corresponding packet is completely lost at the HARQ level. Therefore, the reliability of the HARQ ACK / NACK signal is an important factor in determining the packet error ratio at the HARQ level. Therefore, in the mobile communication system having HARQ and ARQ as described above, the ARQ transmitting side can perform fast retransmission using the HARQ transmission information.

1 is a diagram illustrating the structure and packet structure of a general radio protocol.

Referring to FIG. 1A, the radio protocol is composed of the ARQ layers 120 and 125, the MAC layer 130, and the physical layer 140. One ARQ layer 120, 125 may be configured per service, and satisfies the required QoS through the ARQ operation.

Upper layers 1 and 2 (110 and 115) refer to a protocol stack configured for each service. For example, AMR codec / RTP / UDP / IP or FTP / TCP / IP may be a higher layer. The MAC layer 130 is connected to the plurality of ARQ layers 120 and 125 and multiplexes the plurality of ARQ packets into one HARQ packet. The HARQ operation is performed on the multiplexed HARQ packet. The physical layer 140 performs an operation of transmitting and receiving a HARQ packet through a wireless channel. The ARQ packet refers to a reconfigured packet in which a serial number is allocated to perform ARQ on data transmitted from a higher layer. In addition, the HARQ packet means a packet of a unit transmitted and received on the actual wireless channel through the HARQ operation.

Referring to FIG. 1B, an ARQ packet is transmitted from an ARQ packet header 161 composed of a sequence number (SN, 163), size information 164, and framing information 165 and upper layers 110 and 115. It consists of a payload 162 to which actual data is allocated.

For example, if the IP packet 150 is transmitted from the upper layers 110 and 115 to the ARQ layers 120 and 125, all of the upper IP packets 150 may be transmitted according to a radio channel situation or a scheduling situation. Only part of the IP packet 150 may be transmitted. In this case, reconstructing the IP packet 150 transmitted from the upper layers 110 and 115 to an appropriate size is called framing, and the framing information 165 indicates that the receiving side reconstructs the packet reconstructed to the appropriate size. Information that can be returned as a layer packet (IP packet). The serial number 163 is a serial number sequentially assigned to the ARQ packet 160, and the size information 164 is information indicating the size of the ARQ packet 160. The ARQ layers 120 and 125 use the serial number 163 to store or assemble the serial numbers of the ARQ packets to perform ARQ.

The HARQ packet 170 is composed of a multiplex header 171 and a payload. The multiplexing header 171 includes multiplexing information of the ARQ packet 160. For example, among the ARQ layers, the identifier 120. 125 of the corresponding ARQ layer may be the multiplexing information. In addition, the payload is composed of at least one ARQ packet multiplexed. It is apparent that the radio protocol structure and packet structure are commonly applied to a base station and a terminal.

FIG. 2 is a diagram illustrating an operation of a general HARQ, and FIG. 2 is a diagram illustrating a structure for performing HARQ between a transmitting side and a receiving side. In a reverse packet service, a terminal is a transmitting side and a base station plays a role of a receiving side. On the other hand, in a general forward packet service, a terminal serves as a receiving side and a base station serves as a transmitting side. Therefore, in the following description, it is apparent that the transmitting side and the receiving side are not limited to either the terminal or the base station.

Referring to FIG. 2, since various kinds of services may be provided to one terminal, the transmitting side includes a plurality of higher layer layers 280 and a multiplexing block 275, and the receiving side includes a plurality of higher layer layers. 205 and demultiplexing block 210. The upper layers 205 and 280 may be regarded as, for example, a set of services requiring the same quality of service. For convenience of description, the flows generated in one higher layer are referred to as' QoS flows. Name it '.

The multiplexing block 275 inserts multiplexing information into data generated from various upper layers 275 and delivers the multiplexing information to the HARQ block 272. On the other hand, the demultiplexing block 210 transmits to the appropriate upper layer by using the multiplexing information of the data received from the HARQ block 212.

Here, the HARQ blocks 212 and 272 are apparatuses for performing an HARQ operation, and are composed of a plurality of HARQ processors. The HARQ processor is a basic unit that is responsible for transmitting and receiving HARQ packets, the transmitting HARQ processor is responsible for transmitting and retransmitting user packets, and the receiving HARQ processor is for receiving HARQ packets and HARQ acknowledgment signals. HARQ ACK ') / HARQ Negative Acknowledgment (hereinafter referred to as' HARQ NACK') is responsible for the transmission of the signal.

The HARQ blocks 212 and 272 exist in pairs on the transmitting side and the receiving side, and one HARQ block 212 and 272 includes a plurality of HARQ processors, thereby enabling continuous transmission and reception. The operation of the HARQ processor is composed of operations for transmitting an HARQ packet, receiving HARQ ACK / NACK information, and performing retransmission. Therefore, as an example, when only one HARQ processor exists, other packets cannot be transmitted until user data is transmitted and received HARQ ACK / NACK information. However, when a plurality of HARQ processors are provided, since one processor may transmit data while another processor waits for HARQ ACK / NACK reception, a plurality of HARQ processors may be provided to allow continuous transmission and reception.

The basic operation of the HARQ processor is as follows.

First, the transmitting HARQ processor (any one of HARQ P1 255, HARQ P2 260, HARQ P3 265, and HARQ P4 270) transmits by channel coding data received at the multiplexing block 275. And store the channel coded data in a buffer (not shown) for later retransmission. Upon receipt of the ACK information for the data, the data stored in the buffer is flushed. If the NACK information for the data is received, the data is retransmitted.

On the other hand, the receiving HARQ processor (any one of HARQ P1 215, HARQ P2 220, HARQ P3 225, HARQ P4 230) channel-decodes the data received through the physical channel, The existence of an error is checked through a cyclic redundancy check (CRC) operation that checks whether an error is detected in the data. If an error exists, the data is stored in a buffer and a HARQ NACK signal is transmitted. When the retransmission data for the data is received later, the data stored in the buffer and the retransmitted data are soft-combined and the error is again checked. If it is confirmed that an error still exists, the HARQ NACK signal is transmitted, and the process is repeated. If it is confirmed that the error is resolved, the HARQ ACK signal is transmitted, and the user data is transmitted to the demultiplexing block 210.

As described above, the HARQ packet having an error may be retransmitted and soft combined to be increased through HARQ operation. However, it is inefficient to achieve very low Block Error Rate (hereinafter referred to as 'BLER') only with HARQ operation.

1. This is due to the following two reasons.

1.1. If an error occurs in the HARQ ACK / NACK signal, the HARQ processor does not detect this.

1.2. HARQ transmission / retransmission takes place in a relatively short time, and therefore does not achieve time diversity gain. For example, if the terminal is in deep fading for several tens of msec, it is difficult to successfully transmit the HARQ packet through HARQ retransmission. In order to compensate for the above limitations of HARQ operation, it is necessary to perform ARQ operation. In FIG. 3, an operation of performing HARQ with ARQ will be described.

3 is a diagram illustrating a problem when HARQ and ARQ operate independently according to the prior art.

Referring to FIG. 3, first, an ARQ operation is performed by a transmitting ARQ layer 361, 362, 363 and a receiving ARQ layer 311, 312, 313. The transmitting ARQ layer 361, 362, 363 stores the ARQ packet in the retransmission buffer in case of retransmission even after transmitting the upper layer packet transmitted from the upper layer.

Each of the transmitting ARQ layers 361, 362, and 363 constitutes an ARQ packet corresponding to an amount to be transmitted in a transmission period. In this case, several ARQ packets may be created to fill the amount to be transmitted, or one ARQ packet may be made as much as the amount to be transmitted. In this case, if the size of the ARQ packet to be made does not match the size of the upper layer packet, the upper layer packet may be divided and delivered only in part, or a plurality of higher layer packets may be delivered. At this time, the ARQ packet is constructed by inserting serial number information, size information, and framing information into an upper layer packet. The ARQ packet is delivered to a lower layer and stored in a retransmission buffer for retransmission. Here, the lower layer is composed of a MAC layer, HARQ layer 370 and a physical layer. The HARQ layer 370 multiplexes the delivered ARQ packet into HARQ packets, and then transmits the ARQ packet to the receiver through the physical channel (380).

The receiving ARQ layer is composed of an assembly block, a reception buffer, a retransmission management block, and the like. The physical layer receives the HARQ packet through the physical channel, and the MAC / HARQ layer 320 demultiplexes the received HARQ packet to restore the ARQ packet, and then ARQ to the receiving side ARQ layers 311, 312, and 313. It delivers packets. The reception buffer stores the ARQ packet received from the HARQ layer 320 in accordance with the serial number, and delivers the ARQ packets that can be assembled to the assembly block. The ARQ retransmission management block examines the serial numbers of the ARQ packets stored in the reception buffer, and transmits the ARQ ACK signal for the received ARQ packets and the ARQ NACK signal for the unreceived ARQ packets. 363 to perform the operation of transmitting the data to the servers 341, 342, and 343. The ARQ assembly block performs an operation of reconstructing the ARQ packets into the original upper layer packet after referring to the framing header of the ARQ packets transferred from the reception buffer, and then forwarding them to the upper layer.

The transmitting ARQ layer 361, 362, 363 receiving the response signal to the ARQ packet previously transmitted from the receiving ARQ layer 311, 312, 313 receives the ACK signal, the ARQ in the ARQ retransmission buffer If the packet is discarded and a NACK signal is received, retransmission of the corresponding ARQ packet is scheduled.

As described above, ARQ is performed in units of ARQ packets. Each of the transmitting ARQ layers 361, 362, and 363 attaches and transmits a serial number to the ARQ packet, and the receiving ARQ layer 311, 312, and 313 checks the serial numbers of the received ARQ packets and fails to receive them. Checks for the presence of an ARQ packet. For example, if an ARQ packet having a serial number X and an ARQ packet having a serial number X + 2 is received but no ARQ packet having a serial number X + 1 is received, the receiving ARQ layer is a serial number X + as the sending ARQ layer. Request retransmission of 1 ARQ packet. That is, the NACK signal is transmitted to the transmitting ARQ layer corresponding to the ARQ packet having the serial number X + 1 and requests retransmission of the ARQ packet having the X + 1.

In addition, HARQ operation that operates independently of the ARQ in Figure 3 is as follows.

The transmitting HARQ layer 370 transmits a HARQ packet multiplexing a plurality of ARQ packets, and then retransmits the HARQ packet when receiving the HARQ NACK from the receiving HARQ layer 320. That is, if the transmitting HARQ layer 370 does not receive the HARQ ACK, this operation is repeated by the maximum number of retransmissions. If the HARQ ACK is not received even after repeating the maximum number of retransmissions, that is, when a maximum retransmission limit (hereinafter referred to as 'Maximum Retransmission Limit') occurs, the receiving HARQ layer 320 detects this and performs HARQ ACK / NACK. After transmitting 382, the transmitting HARQ layer 370 receives the request and requests the ARQ layers 361, 362, and 363 to retransmit the corresponding packet.

In this case, the transmitting HARQ layer 370 receives the ARQ NACK to perform retransmission. Therefore, when HARQ Maximum Retransmission Limit occurs, fast retransmission is difficult. In addition, since the receiving side ARQ layer (311, 312, 313) must transmit the NACK for all ARQ packets that have not received, the load on the radio and the processing of the ARQ NACK is large. Moreover, the packet processing is complicated at the ARQ layer because it uses several types of ARQ ACK / NACK. In addition, when the HARQ layer 370 attempts to retransmit and transmits an NACK by determining that an arbitrary ARQ packet is unreceived in the receiving ARQ layer, duplicate retransmission is performed on the same ARQ packet. do. As a result, this problem causes a problem of degrading packet transmission and reception performance.

In connection with the problem of FIG. 3, a method for efficiently operating an HARQ layer and an ARQ layer independently operating as shown in FIG. 4 is proposed. That is, the transmitting HARQ layer 420 uses a method for notifying the transmitting ARQ layer 461, 462, 463 whether the packet transmission failure.

Referring to FIG. 4, the transmitting HARQ layer 470 transmits ARQ layers 461 and 462 for receiving transmission failure information (hereinafter referred to as 'local NACK') and transmission success information (hereinafter referred to as 'local ACK'). 463) to determine whether to retransmit the packet. At this time, the receiving side ARQ layer (411, 412, 413) is characterized in that the ARQ ACK / NACK is not used for the unreceived packet.

In other words, in FIG. 4, the transmitter and the receiver do not perform the ARQ in order to solve a problem in which duplicate retransmission requests may occur as the load and the HARQ layer according to the ARQ operation are used. However, the receiving HARQ layer 420 demultiplexes the HARQ packet transmitted through the transmitting HARQ layer 470, and the corresponding ARQ layers 411, 412, 413 for the demultiplexed ARQ packets. After checking an error with respect to the received ARQ packet, the result is transmitted to the receiving HARQ layer 420.

Accordingly, the receiving HARQ layer 420 transmits a HARQ NACK signal to the transmitting HARQ layer 470, and eventually causes the HARQ layer 470 to perform retransmission.

In addition, the HARQ layer 420 on the receiving side performs HARQ NACK / ACK error detection, if it is determined that the HARQ NACK is deteriorated and recognized as HARQ ACK (hereinafter HARQ NACK / ACK Error) occurs. The NACK / ACK error indicator is transmitted to the transmitting HARQ layer 470. A process of transmitting the error indicator will be described with reference to FIG. 5.

Finally, when the transmitting ARQ layer 461, 462, 463 receives a Local ACK report from the transmitting HARQ layer 470, the corresponding ARQ packet may be removed from the retransmission buffer. On the other hand, when the Local NACK is received, the transmitting ARQ layer 461, 462, 463 prepares to retransmit the corresponding ARQ packet.

5 is a diagram illustrating an operation of detecting a NACK / ACK error according to the prior art.

Referring to FIG. 5, in step 510, a transmitting HARQ layer 555 transmits a HARQ packet to a receiving HARQ layer 505 through a physical channel. The receiving HARQ layer 505 performs error detection on the received HARQ packet. In this case, if an error exists in the received packet, the HARQ NACK is transmitted to the transmitting HARQ layer 555 in step 520. In spite of transmitting the HARQ NACK, if a retransmission packet is not received to the receiving HARQ layer 505 and a new HARQ packet is transmitted in step 530, the receiving HARQ layer 505 is previously determined in step 510. It is assumed that a NACK / ACK error has occurred for the transmitted response signal NACK. That is, an error occurs while the NACK signal for the HARQ packet transmitted in step 510 is transmitted through the wireless channel (520), and thus the HARQ layer 555 of the transmitting side recognizes it as an ACK signal. The side HARQ layer 555 transmits a new HARQ packet in response to the ACK signal.

Accordingly, the receiving HARQ layer 505 that detects the NACK / ACK error transmits the NACK / ACK error indicator to the transmitting HARQ layer 555 in step 555.

FIG. 6 is a diagram illustrating problems occurring when driving HARQ and ARQ according to the prior art described with reference to FIGS. 3, 4, and 5.

Referring to FIG. 6, the case 1 is a case in which the receiving ARQ layer 601 normally receives the ARQ packet 610 transmitted by the transmitting ARQ layer 608 (616). At this time, the ARQ packet 610 is transmitted to the receiving ARQ layer 601 through the transmitting HARQ layer 605 through the receiving HARQ layer 603 (612) to the receiving ARQ layer 601 (616).

The transmitting HARQ layer 605 receives a HARQ ACK indicating that a packet transmitted from the receiving HARQ layer 603 is normally received (step 614), and then starts driving of a timer waiting for receiving a NACK / ACK error indicator in step 630. do. Thereafter, when the timer expires in step 632, the local ACK is reported to the transmitting ARQ layer 608 in step 618.

When the transmitting ARQ layer 608 receives a local ACK report from the transmitting HARQ layer 605, it confirms that the corresponding ARQ packet is normally received until the receiving ARQ layer 601, and removes the packet from the retransmission buffer. Can be.

In case 2, the packet transmission fails even when the transmitting HARQ layer 605 tries to retransmit the maximum number of retransmissions in step 650 (steps 640 to 650). In this case, the transmitting-side HARQ layer 605 reports Local NACK to the transmitting-side ARQ layer 608 in step 652, and the transmitting-side ARQ layer 608 prepares to retransmit the corresponding ARQ packet in step 654.

Case 3 is a case in which HARQ NACK is mistaken for HARQ ACK (step 674). After receiving the HARQ ACK, the transmitting HARQ layer 605 drives a timer waiting for reception of the NACK / ACK error indicator in step 676. If the NACK / ACK error indicator is received from the receiving HARQ layer 605 in step 678 before the timer expires, the local NACK is reported to the transmitting ARQ layer 608 in step 680. Upon receiving the Local NACK, the transmitting ARQ layer 608 prepares to retransmit the corresponding ARQ packet.

2. This method has the advantage of not using ARQ ACK / NACK, but has the following problems.

2.1. Since the HARQ layer must determine and process NACK / ACK errors, the operation of the HARQ layer is complicated.

2.2. If a new HARQ packet is received despite the HARQ NACK transmitted from the receiving HARQ layer 603 side, the NACK / ACK error is determined. However, even when the transmitting HARQ layer 605 transmits the maximum number of retransmissions. If the transmission fails, a new HARQ packet is transmitted, which is difficult to distinguish from the case where a NACK / ACK error occurs.

2.3. Since the transmitting HARQ layer 605 must always report a local ACK for a packet successfully transmitted, the processing overhead of both the transmitting HARQ layer 605 and the receiving ARQ layer 608 becomes large.

2.4. There is no specific way to send a NACK / ACK error indicator.

2.5. There is no solution for missing or modified NACK / ACK error indicators. If it is lost, the receiving HARQ layer 603 waits for the NACK / ACK error indicator, and when the timer expires, it determines that there is no NACK / ACK error and generates a local ACK.

Specific methods for solving the above-mentioned problems have not been proposed in the current mobile communication system, and there is a need for a more effective packet retransmission method for transmitting high-speed data in consideration of the above problems.

Accordingly, the present invention, devised to solve the problems of the prior art operating as described above, provides an efficient retransmission apparatus and method for processing high speed data in a mobile communication system.

In addition, the present invention provides an apparatus and method for performing retransmission by transmitting a minimum signal by distinguishing HARQ operation and ARQ operation in a mobile communication system.

In addition, the present invention provides an apparatus and method for performing retransmission by transmitting a minimum signal to prevent the redundant transmission of the HARQ operation and ARQ operation when transmitting data by distinguishing the HARQ operation and ARQ operation in a mobile communication system do.

The present invention relates to a method of retransmitting high-speed packet data in a transmitting ARQ entity of a mobile communication system that simultaneously performs HARQ and ARQ, wherein the ARQ packets received continuously and normally from the receiving ARQ entity. Receiving a positive acknowledgment signal (ACK) including a last serial number, receiving a negative acknowledgment signal (NACK) in response to an ARQ packet not normally received according to HARQ from a transmitting HARQ entity, and the ACK And checking at least one ARQ packet not normally transmitted in consideration of the NACK, and constructing and retransmitting a retransmission packet including the identified ARQ packet.

The present invention relates to a transmission apparatus for retransmitting high-speed packet data in a mobile communication system that simultaneously performs HARQ and ARQ, and has a negative response signal corresponding to an ARQ packet that is not normally received according to HARQ. In consideration of the HARQ entity reporting the NACK, the NACK reported from the HARQ entity, and the last serial number of consecutive and normally received ARQ packets transmitted from the receiving ARQ entity, And a transmitting-side ARQ entity for identifying at least one ARQ packet not normally transmitted and constructing and retransmitting a retransmission packet including the confirmed ARQ packet.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiments 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.

The present invention to be described later proposes a method for more efficiently performing retransmission in the high-speed packet data transmission in the mobile communication system, between the transmitting HARQ layer and the transmitting ARQ layer using Local NACK, the transmitting HARQ layer In order to solve the problem that the operation of C is somewhat complicated, we propose a method of implementing a simple ARQ operation. That is, in the present invention, retransmission includes retransmission of the ARQ layer through Local NACK of the HARQ layer. In this case, a method of using ARQ ACK is proposed as a countermeasure for the HARQ ACK / NACK error. In addition, the ARQ layer proposes a method for reducing the load on the ARQ NACK processing and the load on the wireless environment by not using the ARQ NACK.

Although the present invention has been described on the basis of LTE system application, retransmission can be applied to all mobile communication systems using operations without any significant modification. In addition, it is apparent that the term 'layer' used below may be used as an entity having a software or hardware structure.

7 is a diagram illustrating an operation of interworking HARQ and ARQ according to the present invention.

In general, in case of using Local ACK, the transmitting HARQ layer should always report the Local ACK to the transmitting ARQ layer for a packet successfully transmitted, thereby causing a problem that a load continuously exists between the HARQ layer and the ARQ layer. In addition, there is a disadvantage in that an additional processing for HARQ NACK / ACK error is required in the HARQ layer. In order to solve this problem, the transmitter-side HARQ layer transmits only Local NACK to the ARQ layer, and overcomes HARQ NACK / ACK errors by using ARQ ACK.

Referring to FIG. 7, the transmitting HARQ layer 770 transmits Local NACK, which is transmission failure information, to the transmitting ARQ layers 761, 762, and 763 to determine whether a corresponding packet is retransmitted.

More specifically, ARQ packets delivered from at least one ARQ layers 761, 762, 763 are delivered to the transmit HARQ layer 770. The transmitting HARQ layer 770 multiplexes the ARQ packets to form HARQ packets of a predetermined size. The HARQ packet includes one ARQ packet or may be composed of at least one ARQ packets. In addition, the present invention is characterized in that the HARQ layer 770 performs HARQ in units of ARQ packets. This is to minimize delay due to processing between the HARQ layer 770 and the ARQ layers 761, 762, and 763 by performing retransmission according to the ARQ packet. The transmitting HARQ layer 770 transmits the HARQ packet configured through the physical channel to the receiving HARQ layer 720.

The receiving HARQ layer 720 demultiplexes the received HARQ packet, and forwards the demultiplexed ARQ packets to the corresponding ARQ layers 711, 712, and 713. The ARQ layers 711, 712, and 713 check the error for the received ARQ packet, and then transfer the result to the receiving HARQ layer 720. The receiving HARQ layer 720 transmits a NACK signal to the transmitting HARQ layer 770 for the packet in error.

The transmitting side HARQ layer 770 performs retransmission corresponding to a preset maximum retransmission limit value, and when the number of retransmissions for the same packet exceeds the set maximum retransmission limit value, the corresponding transmission side processing the corresponding ARQ packet. Report Local NACK to ARQ layer (one of 761, 762, 763). The corresponding ARQ layer 761, 762, and 763 having received the Local NACK report from the transmitting HARQ layer 770 prepares to retransmit the corresponding ARQ packet.

In relation to the HARQ operation, the present invention is characterized in that the receiving ARQ layer 711, 712, 713 transmits an ACK to the transmitting ARQ layer only for the ARQ packet normally received. In this case, the receiving ARQ layer 711, 712, 713 transmits an ACK including information in the packets accumulated normally to the transmitting ARQ layer 761, 762, 763.

 The HARQ layer 770 manages a HARQ transmission state table as shown in Table 1 below. The block managing the transmission state table may be the HARQ layer 770 itself, or as shown in FIG. 7, a HARQ transmission state unit 772 may be separately provided. At this time, it is apparent that the HARQ layers 770 and 720 include a plurality of HARQ processors to perform HARQ operations.

Table 1 below is a transmission state table included in the HARQ transmission state unit 772 according to the present invention.

HARQ Processor ID  ARQ Packet ID (ARQ Layer ID, ARQ Packet Sequence Number)

As shown in Table 1, the transmission state table maps and stores the actual transmitting side HARQ process identifier information constituting the HARQ packet and information on the corresponding ARQ packet.

The transmitting-side HARQ layer 770 of the present invention can confirm the corresponding ARQ layer and ARQ packet serial number that processed the ARQ packet through the HARQ transmission state table, and can also confirm the packet processed as the actual ACK. . Therefore, when configuring a HARQ packet through the transmission state table, the transmitting HARQ layer 770 displays information on the included ARQ packet in the HARQ transmission state table entry of the corresponding HARQ processor ID. After the transmission attempt, if the HARQ ACK is received, the transmission state table entry for the corresponding HARQ frame (the processor ID) is deleted. In addition, when the maximum retransmission limit value is reached according to the HARQ operation ('Maximum Retransmission Limit' occurs), referring to the transmission status table entry of the corresponding HARQ processor ID, Local NAKC including a sequence number to the relevant ARQ layer. After reporting, the transfer state table entry is deleted.

8 illustrates generation of a Local NACK according to the present invention.

Referring to FIG. 8, the transmitting ARQ layer 851 performs framing of data transmitted from an upper layer into an ARQ packet, and then transmits the data to the HARQ layer 770 in step 820. In step 822, the transmitting HARQ layer 852 transmits the delivered ARQ packet to the receiving HARQ layer 802. That is, according to the present invention, the HARQ layer 852 configures and transmits an HARQ packet in the form of an ARQ packet including an ARQ packet transmitted from the ARQ layer 851 or at least one ARQ packet.

The receiving HARQ layer 802 checks whether the transmitted HARQ packet is in error and then transmits a NACK to the transmitting HARQ layer 852 according to the occurrence of the error in step 824. In step 826, the transmitting side HARQ layer 852 retransmits the HARQ packet having a transmission error. The receiving HARQ layer 802 reconfirms whether the retransmitted HARQ packet is in error and transmits a NACK to the transmitting HARQ layer 852 in step 828.

In step 830, the HARQ layer 852 determines whether the number of retransmissions for the HARQ packet exceeds a preset maximum retransmission limit value. That is, the number of retransmission limits for the NACK signal that is the response signal of the HARQ packet is checked. When the transmitting HARQ layer 852 determines in step 832 that the number of retransmissions of the HARQ packet exceeds a preset maximum retransmission limit value, the ARQ packet transmitted in step 820 to the transmitting ARQ layer 851. Report that NACK has occurred for Local) through Local NACK.

As described above, the HARQ layer of the present invention checks whether the initial ARQ packet is an error and transmits 'Local NACK for ARQ' to the ARQ layer as a response signal.

Therefore, the ARQ layer checks Local NACK reported from the HARQ layer and performs retransmission. The present invention has the effect of reducing the processing load according to the use of Local ACK by reporting only the Local NACK for the ARQ packet that the HARQ layer failed to transmit. In addition, the retransmission is faster and easier than the conventional retransmission after receiving the ARQ NACK. In addition to the transmission of the Local NACK, the present invention includes an operation of transmitting and receiving an ARQ ACK in preparation for the occurrence of HARQ NACK / ACK error. This will be described through the following first and second embodiments.

First embodiment

9A and 9B illustrate an operation of a HARQ and an ARQ layer for transmitting and receiving an ACK signal according to a first embodiment of the present invention. Here, the transmitting side according to the retransmission has an ARQ layer (901, hereinafter referred to as 'ARQ Tx') and HARQ layer (903, hereinafter referred to as 'HARQ Tx'), the receiving side HARQ layer (905, hereinafter 'HARQ Rx') And an ARQ layer 908 (hereinafter referred to as 'ARQ Rx'). 910, 912, 914 and 916 show a retransmission buffer state and a packet information table state of a transmitter related to retransmission of the ARQ Tx, and 960 and 962 show the buffer state of a receiver side. A detailed description of the buffer status of each layer will be described with reference to 9b.

First, referring to 9a, the ARQ Rx 908 normally receives the previously transmitted ARQ packets 1 and 2. This can be seen through the receiving side ARQ buffer of 960.

In step 920, the ARQ Tx 901 transmits ARQ packets 3 and 4 to the HARQ Tx 903. In step 922, the HARQ Tx 903 forwards the ARQ packets 3 and 4 to the HARQ Rx 905. In step 924, the HARQ Rx 905 determines that an error occurs in the ARQ packets 3 and 4, and transmits a NACK signal to the HARQ Tx 903. However, during the transmission of the NACK signal of the ARQ packets 3 and 4, which are the response signals transmitted to the HARQ Tx 903, an error occurs as an ACK signal. Accordingly, in step 926, the ARQ Tx 901 determines that the ARQ packet 3, Determining that 4 has been transmitted normally, ARQ packets 5 and 6 of the next serial number are transmitted to HARQ Tx 903.

In step 928, the HARQ Tx 903 forwards the ARQ packets 5 and 6 to the HARQ Rx 905. In step 930, the HARQ Rx 905 checks whether the transmitted ARQ packets 5 and 6 are in error, and then transfers the ARQ packets 5 and 6 to the ARQ Rx 908 as they do not occur in the error. At this time, the receiving buffer status of the ARQ Rx 908 is equal to 962. In operation 932, the HARQ Rx 905 transmits an ACK according to the normal reception of the ARQ packets 5 and 6 to the HARQ Tx 903. The ACK of the ARQ packets 5 and 6 is normally transmitted to the HARQ Tx 903.

Accordingly, in step 934, the ARQ Tx 901 forwards the ARQ packet 7 to the HARQ Tx 903. The buffer state of the transmitting ARQ Tx 901 is equal to 912. The HARQ Tx 903 receiving the ARQ packet 7 in step 936 transmits the ARQ packet 7 delivered from the ARQ Tx 901 to the HARQ Rx 905. At this time, in step 938, the HARQ Rx 905 determines that an error occurs in the ARQ packet 7, and transmits a NACK to the HARQ Tx 903. In operation 940, the HARQ Tx 903 retransmits the ARQ packet 7. In spite of retransmission, in step 942, the HARQ Rx 905 confirms that an error has occurred in the HARQ packet, and transmits a NACK to the HARQ Tx 903 again. The retransmission of the ARQ packet 7 of the HARQ Tx 903 continues according to the occurrence of the error of the ARQ packet 7 until the preset maximum retransmission number is reached (944, 946).

In this case, the HARQ Tx 903 confirms that the number of retransmissions of the ARQ packet 7 reaches the preset maximum number of retransmissions, and in step 948, the Local NACK for the ARQ packet 7 is generated by the ARQ Tx 901. Report.

In step 950, the ARQ Tx 901 transmits the ARQ packet 7 and the packet 8 which is the packet 7 next packet to the HARQ Tx 903. At this time, the buffer state of the transmitting side ARQ Tx 901 is equal to 914.

At this time, in step 952, the ARQ Rx 908 transmits an ARQ ACK according to the ARQ operation. The ARQ ACK does not send an ACK for all received packets, but transmits an ACK including a serial number for a last received last packet. In addition, according to the feature of the present invention, it does not transmit NACK for unreceived ARQ packets. In addition, as the ARQ Rx 908 transmits the ARQ ACK for the ARQ packet normally received, the ARQ Tx 901 performing retransmission according to the Local NACK ensures the retransmission reliability for the same ARQ packet.

In the present invention, the ARQ Tx 901 manages the HARQ packet configuration information table. This is because the HARQ Tx 903 performs HARQ in units of ARQ packets.

As described above, since most retransmissions will be made by Local NACK of HARQ Tx 903, only a minimum ARQ ACK is transmitted to cope with HARQ NACK / ACK errors and to manage retransmission buffers of ARQ Tx 901. . That is, ARQ Rx 908 does not send an ACK for all received packets, and transmits an ACK including only the serial number of the last packet continuously received in the format suggested by the present invention, and does not transmit additional NACK.

Through this, the ACK / NACK processing operation of the ARQ Tx 901 and the ARQ Rx 908 can be implemented simply and efficiently. In addition, the amount of transmission / reception of ARQ ACK / NACK is also reduced, so that limited radio resources can be efficiently used. In addition, the ARQ Rx 908 distinguishes and transmits an ACK transmitted for retransmission buffer management and an ARQ ACK transmitted when an ARQ packet not received occurs.

In addition, the HARQ Tx 903 reports Local NACK to the ARQ Tx 901 when it fails to receive the ARQ ACK even though the number of retransmissions is attempted. ARQ Tx 901 attempts to retransmit corresponding packets reported from HARQ Tx 903.

Referring to FIG. 9B, the ARQ Tx 901 manages a packet information table in association with an ARQ packet configuration. The smallest serial number among the ARQ packets constituting the same HARQ packet is displayed in a first sequence number field, and the serial numbers of other ARQ packets are displayed in the same HARQ packet configuration sequence number information field. In this way, the first sequence number field is set aside, and the sorting is maintained when the table is updated to facilitate the search of retransmission packets.

For example, as the ARQ Tx 901 transmits the ARQ packets 3 and 4 to the HARQ Tx 903 in step 920, the HARQ packet previously transmitted to the packet information table as shown in the packet information table 910 (the same as the initial sequence number packet 1 HARQ). Information of the packet including packet 2, which is another packet of?, And the initial sequence number are indicated by packet 3, and packet 4 is indicated by sequence numbers within the same HARQ packet.

For the ARQ packet 7 transmitted by the ARQ Tx 901 in step 934, an initial sequence number is indicated as packet 7 in the packet information table as shown in 912, and the sequence number information is null because no other packet exists in the same HARQ packet configuration. (NULL) field. In this case, an initial sequence number is indicated by packet 5 and a field indicated by packet 6 as a sequence number in the same HARQ packet means that the field is previously updated with respect to ARQ packets 5 and 6 transmitted in step 926.

In step 950, the retransmission buffer indicates packet 7 that has been retransmitted as the ARQ Tx 901 receives Local NACK for packet 7 from HARQ Tx 903 as an initial sequence number, and indicates a sequence number in the same HARQ packet as packet 8 The packet information table denoted by is equal to 914.

In step 954, the retransmission buffer includes a HARQ packet configuration information table such as 916 as the ARQ Tx 901 receives an ACK including the first sequence number consecutively received from the ARQ Rx 908. That is, the ARQ Tx 901 confirms that ARQ packet 3 is not in retransmission through the received ACK and confirms that an HARQ NACK / ACK error occurs. Accordingly, a HARQ packet configuration information table for confirming that packets 1 and 2 are normally received through the ACK and deleting the packets 1 and 2 from the retransmission buffer is provided.

That is, the ARQ ACK transmission of the present invention for solving the problem of the HARQ ACK / NACK error is effective when using a radio protocol that can include multiple ARQ initial transmission packets of the same layer in the same HARQ packet. In addition, it is effective to use the radio protocol when only one ARQ initial transport packet of the same layer is included in the HARQ packet. In this case, it is not necessary to manage the HARQ packet configuration information table. This is because it is necessary to determine whether to retransmit only the ACK serial number + the first packet and then retransmit.

10 is a diagram illustrating a format structure of an ACK signal according to a first embodiment of the present invention.

Referring to FIG. 10, when an ARQ packet that has not been received, ARQ Rx transmits an ACK by filling the Cumulative ACK Sequence Number field 1020 with the largest serial number of the serial number of the received packet. Here, the header 100 may insert the actual processor identifier information that processed the ARQ packet. In addition, the Type Bit 1010 is a field indicating whether there is an ARQ packet not received and is an optional bit that can be added or deleted according to the implementation of the ACK. That is, the Type Bit 1010 set to '0' means an ACK transmitted for retransmission buffer management of the transmitting ARQ layer, and set to '1' indicates that there is an ARQ packet not received.

11 is a signal flowchart illustrating a process of receiving an ACK signal by a transmitting side according to the first embodiment of the present invention.

Referring to FIG. 11, in step 1110, the ARQ Tx receives an ACK from the ARQ Rx. In step 1112, it is checked whether the ACK Type field is set to '1'. If the ACK Type field is set to '1', step 1114 is performed. Here, the type field of the ACK is set to '1' means that there is a packet that has not been received in ARQ Rx. In step 1114, the ARQ Tx checks the Cumulative ACK Sequence Number field of the ACK to identify the last sequence number of the continuously received packet. Thereafter, in step 1116, the ARQ Tx determines whether to retransmit the ACK serial number + first packet.

In step 1118, the ARQ packets below the Cumulative ACK Sequence Number are discarded to update the retransmission buffer. The HARQ packet is configured in consideration of the retransmission buffer updated in step 1124, the HARQ packet configuration information table is updated, and the corresponding ARQ packet is retransmitted in step 1230. Here, the HARQ packet is the same as the ARQ packet. On the contrary, in step 1112, the ARQ Tx confirming that the ACK Type field is set to '0' proceeds to step 1120 to update the retransmission buffer.

After receiving Local NACK from HARQ Tx in step 1122, the ARQ Tx configures the HARQ packet to retransmit the packet corresponding to Local NACK in step 1124, updates the HARQ packet configuration information table, and then, in step 1126, Local NACK. Retransmit the corresponding ARQ packet.

Second embodiment

In the following second embodiment, when the transmitting side transmits the ACK, the case in which the information of the ARQ packet corresponding to the NACK is added and transmitted is described.

12 is a diagram illustrating the operation of the HARQ and ARQ layer for transmitting and receiving an ACK signal according to a second embodiment of the present invention.

Referring to FIG. 12, the ARQ Rx 1208 normally receives the previously transmitted ARQ packets 1 and 2. This can be seen through the receiving ARQ buffer of 1260.

In step 1220, the ARQ Tx 1201 transmits ARQ packets 3 and 4 to the HARQ Tx 1203. In step 1222, the HARQ Tx 1203 transmits the ARQ packets 3 and 4 to the HARQ Rx 1205. In this case, in step 1224, the HARQ Rx 1205 determines that an error occurs in the ARQ packets 3 and 4, and transmits a NACK signal to the HARQ Tx 1203.

In step 1226, the ARQ Tx 1201 transmits ARQ packets 5, 6, and 7 to the HARQ Tx 1203. In step 1228, the HARQ Tx 1203 transmits the ARQ packets 5, 6, and 7 to the HARQ Rx 1205. In this case, in step 1230, the HARQ Rx 1205 confirms that an error occurs in the ARQ packets 5, 6, and 7 and transmits a NACK signal to the HARQ Tx 1203, but an ARQ NACK / ACK error occurs.

In step 1232, the ARQ Tx 1201 transmits ARQ packets 8 and 9 to the HARQ Tx 1203. In step 1234, the HARQ Tx 1203 transmits the ARQ packets 8 and 9 to the HARQ Rx 1205. In step 1236, the HARQ Rx 1205 confirms that the ARQ packets 8 and 9 are normally received, and transmits an ACK signal to the HARQ Tx 1203. In operation 1238, the HARQ Rx 1205 delivers the ARQ packets 8 and 9 to the ARQ Rx 1208. The ARQ Rx 1208 updates and manages a reception buffer for packets 1, 2, 8, and 9 that are normally received.

In step 1240, the HARQ Tx 1203 retransmits the ARQ packets 3 and 4 to the HARQ Rx 1205. In step 1242, the HARQ Rx 1205 determines that an error of the retransmitted ARQ packets 3 and 4 also occurs, and transmits a NACK signal to the HARQ Tx 1203. In step 1244, the HARQ Tx 1203 retransmits the ARQ packets 3 and 4 to the HARQ Rx 1205.

Accordingly, in step 1248, the HARQ Tx 1203 reports to the ARQ Tx 1201 that a Local NACK is generated for the ARQ packets 3 and 4. In step 1250, the ARQ Tx 1201 checks the retransmission buffer and then retransmits the ARQ packets 3 and 4.

At this time, in step 1252, the ARQ Tx 1201 receives an ARQ ACK from the ARQ Rx 1208. Here, the ARQ ACK is an ACK including the serial number of the last packet received continuously and information on the number of packets not received continuously.

Accordingly, in step 1226, the ARQ Tx 1201 receives ARQ 2 consecutively through the ACK, and the number of packets not continuously received is 5, so that the ARQ Tx 1201 may receive the ARQ packets 3, 4, 5, 6, and 7 Try to perform the retransmission. However, since the ARQ packets 3 and 4 are attempting to retransmit by Local NACK, the information on the ARQ packets 3 and 4 is ignored, and the ARQ packets 3 and 4 are determined to be HARQ ACK.NACK errors for the ARQ packets 5, 6, and 7 to perform retransmission.

In the second embodiment, the ARQ Tx 901 does not manage a HARQ packet configuration information table. That is, the ARQ Tx determines the HARQ ACK / NACK error by looking at the NACK information of the unreceived packet through the number of unreceived packets included in the ACK. That is, when it is determined that an HARQ ACK / NACK error has occurred, retransmission is performed for ARQ packets that are not continuously received after the serial number of the normally received packet of the ACK, so that the HARQ packet configuration information table does not need to be managed separately. do.

13 is a diagram illustrating a format structure of an ACK signal according to a second embodiment of the present invention.

Referring to FIG. 13, when an ARQ packet that has not been received, ARQ Rx transmits an ACK by filling the Cumulative ACK Sequence Number field 1310 with the largest serial number of the serial number of the received packet. Here, the header 1300 may insert the actual processor information processing the ARQ packet. Further, the ACK is configured to include the total number of unreceived packets that have not been received continuously in the Number of Consecutive missed packet field 1320 after the serial number of the last received packet continuously.

 In other words, the ARQ Tx 901 allocates and transmits the number of ARQ packets that are not continuously received after the ACK serial number to the Number of Consecutive missed packet field, and the Number of Consecutive missed packet field eventually manages retransmission buffer. It can be transmitted by dividing the ACK transmitted for ACK and the ACK transmitted when ARQ packet is not received. That is, when the Number of Consecutive missed Packet field is set to '0' and when it is not, the value of 0 means that all transmitted ARQ packets are normally transmitted. Can be considered as ACK.

14 is a signal flowchart illustrating a process of receiving an ACK signal by a transmitting side according to a second embodiment of the present invention.

Referring to FIG. 14, in step 1410, the ARQ Tx receives an ACK from the ARQ Rx. In step 1412 and in step 1414, the ARQ Tx checks the Cumulative ACK Sequence Number field of the ACK to identify the last sequence number of consecutively received packets. Thereafter, in step 1414, the ARQ Tx checks the Number of Consecutive missed packet field to identify the number of consecutive unreceived packets after the last sequence number of the continuously received packet. In step 1416, the ARQ Tx is reported as a Local NACK among the unreceived packet numbers to check whether there are packets to be retransmitted. In this case, if there is no packet being retransmitted, the process proceeds to step 1418 and retransmits in the order of serial number among the unreceived packets. At this time, the retransmission buffer is updated and retransmission is performed. For example, the number of the last packets received in FIG. 12 is packet 2, and the total number of unreceived packets is 5 in total. At this time, packets 3 and 4 are being retransmitted due to Local NACK. Accordingly, the ARQ Tx ignores the packets 3 and 4 that are attempting retransmission and performs retransmission for the packets 5, 6, and 7. On the other hand, if there is no packet being retransmitted, retransmission is performed in order of packets 3, 4, and 5.

In contrast, in step 1414, the ARQ Tx confirming that the Number of Consecutive missed packet field is set to '0' determines that the ACK is an ACK for updating the retransmission buffer, and proceeds to step 1420 to update the retransmission buffer.

In addition, in step 1430, the ARQ Tx that receives the Local NACK from the HARQ Tx configures an HARQ packet including the corresponding retransmission ARQ packet to retransmit the packet corresponding to the Local NACK in step 1432, and then corresponds to the Local NACK in step 1434. Retransmission of the ARQ packet is performed. For example, this may be described as a process of receiving and receiving the Local NACK, and updating the retransmission buffer for retransmitting the packets 3 and 4 and retransmitting the packets 3 and 4.

As described above, the ARQ Tx according to the second embodiment of the present invention receives an ACK from the ARQ Rx including serial number information of the last packet normally received and information including the total number of unreceived packets. It is not necessary to manage a separate HARQ packet configuration information table according to retransmission.

15 is a diagram illustrating an operation for preventing duplicate transmission according to the present invention, and FIGS. 16A, 16B, 16C, and 16D illustrate an example of a HARQ transmission state table for preventing duplicate transmission according to the present invention. One drawing.

Referring to FIG. 15, the ARQ Tx 1501 sequentially delivers ARQ packets 1, 2, 3, and 4 to the HARQ Tx 1503 (1511, 1512, 1513, and 1514). At this time, the HARQ Tx 1503 has a HARQ transmission status unit 772, as shown in FIG. The HARQ transmission state unit 772 manages a HARQ transmission state table as shown in FIG. 16A to report Local NACK to each ARQ layer 761, 762, 763. In the present invention, the case of four HARQ processors is taken as an example. In addition, it illustrates a case in which only one ARQ entity to operate.

After step 1514, the HARQ Tx 1503 manages a HARQ transmission state table as shown in FIG. 16A. The ARQ packets 1, 2, 3, and 4 are transmitted to the HARQ Rx 1505 via radio (1511, 1512, 1513, and 1514). The HARQ Rx 1505 performs error checking on the received ARQ packets 1, 2, 3, and 4 and then transmits a response signal to the HARQ Tx 1503. For example, the HARQ Rx 1505 receives the ACK 1521 as the ARQ packet 1 is normally received, the NACK 1522 as the ARQ packet 2 is not normally received, and the NACK as the ARQ packet 3 is not normally received. ARQ packet 4 is normally received and transmits ACK 1524 to HARQ Tx 1503.

After the step 1524, the HARQ Tx 1503 deletes the packet having received the ACK from the HARQ transmission state table, and manages the HARQ transmission state table as shown in FIG. 16B.

In addition, the HARQ Rx 1505 normally forwards the ARQ packet 1 and the ARQ packet 4 to the ARQ Rx 1508 as the ARQ packet 1 and the ARQ packet 4 are normally received. At this time, the ARQ Rx 1508 waits for a predetermined time and then delivers the ARQ ACK for the normally received packet to the ARQ Tx 1501. This is to assure maximum reliability according to the ARQ operation and the HARQ operation.

On the other hand, according to the NACK signals 1522 and 1523 transmitted from the HARQ Rx 1505, the HARQ Tx 1503 retransmits the ARQ packet 2 and the ARQ packet 3 (1532 and 1533), and the HARQ Rx 1505 is Check for errors in the retransmitted two or three packets. At this time, the HARQ Rx 1505 determines that the ARQ packet 2 is normally received, transmits an ACK signal to the HARQ Tx 1503 (1542), and delivers the ARQ packet 2 normally received to the ARQ Rx 1508. On the other hand, the ARQ packet 3 transmits a NACK signal to the HARQ Tx 1503 when an error occurs (1543).

At this time, the HARQ Tx 1503 that receives the NACK for the ARQ packet 3 checks whether the number of retransmissions for the ARQ packet 3 exceeds a preset maximum retransmission limit value, and sets the maximum retransmission limit value for the ARQ packet 3 to be set. If exceeded, a local NACK is generated and an NACK of the ARQ packet 3 is reported to the ARQ Tx 1501 (1553). After that, since the packet having Local NACK is also deleted from the HARQ transmission state table, the HARQ Tx 1503 manages the HARQ transmission state table as shown in FIG. 16C.

The ARQ Tx 1501 retransmits ARQ packet 3 through the Local NACK 1553 (1563). In addition, the HARQ Tx 1503 manages a HARQ transmission state table as shown in FIG. 16D.

HARQ Tx 1503 retransmits ARQ packet 3 to HARQ Rx 1505 over the air (1563). The HARQ Rx 1505 checks the error of the transmitted ARQ packet 3, and if it is confirmed that no error occurs, the HARQ Rx 1505 transmits the normally received ARQ packet 3 to the ARQ Rx 1508 (1565). In addition, the HARQ Rx 1505 transmits an ACK to the HARQ Tx 1503 to notify that the ARQ packet 3 is normally received (1573).

Unlike the HARQ operation, in step 1580, the ARQ Rx 1508 detects that transmission of the ARQ packet 3 is not completed for the predetermined time. Accordingly, the ARQ Tx 1201 transmits an ARQ ACK to the ARQ TX 1501 indicating that there are up to ARQ 2 packets continuously received in step 1581, and that there is one packet that has not been continuously received. That is, in step 1580, the ARQ ACK for performing retransmission on the ARQ packet 3 that is not normally received is transmitted to the transmitting ARQ Tx 1501.

However, the ARQ packet 3 is attempting to retransmit by Local NACK as described in steps 1553 and 1563. In this case, ARQ Tx 1501 should not attempt to retransmit ARQ packet 3.

For example, in the case of FIG. 15, since step 1563 is a step in which the ARQ Tx 1501 has already sent down ARQ packet 3 to the HARQ ACK 1573, retransmission in the ARQ TX 1501 is completed, and thus retransmission is performed. It is an example of not being. If the ARQ Tx 1501 refers to the HARQ transmission state table of FIG. 16D, it can be confirmed that the HARQ Tx 1503 is attempting to retransmit the packet 3 since the HARQ Tx 1503 is still received before the HARQ ACK 1573. Accordingly, the ARQ TX 1501 may prevent duplicate transmission for the same ARQ packet 3 by not attempting to retransmit the ARQ.

In other words, when the ARQ Tx 1501 determines retransmission for the ARQ ACK (step 1581), whether the ARQ Tx 1501 is preparing for retransmission by a Local NACK or a previously transmitted ARQ ACK from the corresponding HARQ Tx 1503. If the retransmission is not ready, the HARQ Tx 1503 checks whether the HARQ Tx 1503 is retransmitting the corresponding packet by referring to the HARQ transmission state table. That is, only when the HARQ Tx 1503 does not retransmit the corresponding packet, the ARQ retransmission attempt is finally determined.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

According to the present invention, in a mobile communication system performing HARQ, HARQ Tx transmits only Local NACK, and ARQ Rx transmits only ACK including the last serial number of a normally received packet to load the mutual load according to HARQ operation and ARQ operation. As a result, it has the advantage of improving the system performance of the entire system. In other words, the ARQ and HARQ operations are performed more quickly, thereby serving high-speed data with improved efficiency.

Claims (12)

A method for retransmitting high-speed packet data in a transmitting ARQ entity of a mobile communication system that simultaneously performs HARQ and ARQ, Receiving a positive acknowledgment signal (ACK) including the last serial number of consecutive and normally received ARQ packets from a receiving ARQ entity, Receiving a negative response signal (NACK) from an transmitting HARQ entity in response to an ARQ packet not normally received according to HARQ; Identifying at least one ARQ packet not normally transmitted in consideration of the ACK and NACK, and constructing and retransmitting a retransmission packet including the confirmed ARQ packet. The method of claim 1, The transmitting HARQ entity repeatedly performing complex retransmission of the transmitted ARQ packet within a preset maximum retransmission limit value; And reporting the NACK to the transmitting ARQ entity when the number of times of performing the complex retransmissions exceeds the preset maximum retransmission limit value. The method of claim 2, The transmitting-side HARQ entity transmits only the NACK to the transmitting-side ARQ entity. The method of claim 1, And the receiving ARQ entity transmits an ACK including the last serial number of consecutive and normally received ARQ packets and identifier information of the corresponding ARQ entity that processed the ARQ packet to the transmitting ARQ entity. The method of claim 4, wherein The receiving ARQ entity is an ACK including the last serial number of consecutive and normally received ARQ packets, identifier information of the corresponding ARQ entity that processed the ARQ packet, and a type bit including the presence or absence of an unreceived packet. Retransmission method characterized in that the transmission to the transmitting ARQ entity. The method of claim 4, wherein The transmitting ARQ entity confirms the last serial number of a packet normally received from the ACK transmitted from the receiving ARQ entity; Checking whether a packet following the last serial number is being retransmitted by a transmitting HARQ entity; And if the next packet is not in retransmission, retransmitting a packet including the next packet to perform retransmission. The method of claim 6, And the retransmission packet is a packet composed of at least one ARQ packet. The method of claim 4, wherein The transmitting ARQ entity identifies ARQ packets not normally transmitted in consideration of the ACK and NACK, assigns the earliest packet number to the start sequence number field among the ARQ packets, and configures the ARQ packets of the next order. Updating the retransmission buffer to allocate And retransmitting a retransmission packet to be retransmitted according to the updated retransmission buffer to a transmitting HARQ entity and performing retransmission. The method of claim 4, wherein The receiving ARQ entity includes an ACK including the last serial number of consecutive and normally received ARQ packets, identifier information of the corresponding ARQ entity that processed the ARQ packet, and the total number of unreceived packets. Retransmission method characterized in that the transmission. The method of claim 9, The transmitting ARQ entity receiving the ACK including the last serial number of the packet normally received from the receiving ARQ entity and the number of unreceived packets; Checking the last serial number of the packet normally received from the positive response signal; Checking whether unreceived packets following the last serial number are retransmitted; And if the next packet is not in the retransmission process, reconfiguring a retransmission packet including the next packet, transmitting the retransmission packet to a transmitting HARQ entity, and performing retransmission. A transmitting apparatus for retransmitting high-speed packet data in a mobile communication system which simultaneously performs a complex retransmission (HARQ) and a retransmission (ARQ), An HARQ entity reporting a negative response signal (NACK) in response to an ARQ packet not normally received according to HARQ, At least one ARQ packet not normally transmitted, taking into account the NACK reported from the HARQ entity and a positive acknowledgment signal (ACK) including the last serial number of consecutive and normally received ARQ packets transmitted from the receiving ARQ entity; And a transmitting-side ARQ entity for constructing and retransmitting a retransmission packet including the identified ARQ packet. The method of claim 10, The transmitting ARQ entity receives a negative response signal (NACK) from the receiving HARQ entity corresponding to the ARQ packet that was not normally received according to the HARQ, and then updating the retransmission buffer; Receiving an affirmative response signal (ACK) including the last serial number of consecutive and normally received ARQ packets from the receiving ARQ entity and confirming whether the ARQ packet is being retransmitted through the updated retransmission buffer; And retransmitting the ARQ packet to prevent ARQ retransmission.

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