KR20060026813A - Method and apparatus for determining automatic retransmission request control information in mobile communication system supporting enhanced uplink dedicated channel - Google Patents

Abstract

The present invention proposes a specific method and apparatus for determining an RV parameter which is control information related to E-DCH HARQ when an enhanced uplink dedicated transport channel (E-DCH) is used. A mobile communication system supporting a complex automatic retransmission request for a packet data service includes a retransmission number indicating the number of retransmissions of packet data to determine a redundancy version (RV) parameter for distinguishing between initial transmission and retransmissions of packet data; Acquires transmission format information of the packet data, selects an RV parameter set corresponding to the transmission format information among a plurality of predetermined RV parameter sets, and selects the retransmission number and the selected RV parameter set from the selected RV parameter set Determine the RV parameter according to the predetermined maximum number of RV for. The present invention can maximize the gain of HARQ, and can set the RV for each data rate or initial transmission coding rate.

WCDMA, E-DCH, HARQ, Redundancy Version, Self Decodable, Self Decodable, Incremental Redundancy, Chase combining

Description

TECHNICAL AND APPARATUS FOR THE DETERMINATION OF THE HARQ CONTROL INFORMATION IN MOBILE TELECOMMUNICATION SYSTEM FOR ENHANCED UPLINK DEDICATED CHANNEL}             

1 is a message flow diagram illustrating a transmission and reception procedure through a general E-DCH.

2 is a flowchart illustrating a terminal according to the RV determination method proposed by the present invention.

3 is a flowchart illustrating a base station according to the RV determination method proposed by the present invention.

4 is a diagram showing an apparatus for transmitting a terminal according to a preferred embodiment of the present invention.

5 is a diagram illustrating a receiving apparatus of a base station according to a preferred embodiment of the present invention.

The present invention relates to a cellular code division multiple access (CDMA) communication system, and more particularly, to provide a method and apparatus for determining control information for a hybrid automatic repeat request (HARQ).

Third generation, based on the European mobile system Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), and using Wideband Code Division Multiple Access (CDMA) UMTS (Universal Mobile Telecommunication Service) system, a mobile communication system, is a consistent service that enables mobile phone or computer users to transmit packet-based text, digitized voice or video, and multimedia data at high speeds of 2 Mbps or more anywhere in the world. To provide.

In particular, in the UMTS system, the uplink from the user equipment (UE) to the base station (BS, Node B), that is, the uplink (uplink: UL) communication in order to further improve the performance of packet transmission in the uplink (UL) communication A transport channel called an Enhanced Uplink Dedicated Channel (hereinafter referred to as EUDCH or E-DCH) is used. E-DCH supports Adaptive Modulation and Coding (AMC), Hybrid Automatic Retransmission Request (HARQ), and Short TTI (Shorter Transmission Time Interval) to support more stable high-speed data transmission. Techniques such as size, base station control scheduling, and the like.

AMC is a technology that improves the resource usage efficiency by determining the modulation method and the coding method of the data channel according to the channel state between the base station and the terminal. The combination of modulation scheme and coding scheme is called MCS (Modulation and Coding Scheme), and various MCS levels can be defined according to the supported modulation scheme and coding scheme. AMC adaptively determines the level of the MCS according to the channel state between the terminal and the base station, thereby increasing the resource usage efficiency.

HARQ refers to a technique for retransmitting a packet to compensate for the error packet when an error occurs in an initially transmitted data packet. The short TTI size allows for a TTI less than 10ms, the minimum TTI of the current Rel5, to reduce retransmission latency and consequently enable high system performance.

In case of transmitting data using E-DCH, base station control scheduling determines whether uplink data is transmitted and an upper limit of possible data rate by the base station, and transmits the determined information to the terminal as a scheduling command. Refers to the scheduling command refers to a method of determining and transmitting the data rate of the uplink E-DCH possible.

The base station control scheduling allocates a low data rate to terminals far away from the base station while preventing the measurement noise increase (RoT) of the base station from exceeding a target value in order to improve the performance of the entire system. And, it is performed by assigning a high data rate to the terminals near. RoT represents a radio resource used by the base station in the uplink, and is defined as in Equation 1 below.                         

RoT = I ₀ / N ₀

I ₀ denotes a power spectral density for the entire reception band of the base station and represents the total amount of uplink signals received by the base station. N ₀ is the thermal noise power spectral density of the base station. Therefore, the maximum RoT allowed is the total radio resource that the base station can use in the uplink. The total RoT of the base station is represented by the sum of inter-cell interference, voice traffic, and E-DCH traffic. If the base station control scheduling is used, it is possible to prevent a plurality of terminals from transmitting packets of a high data rate at the same time, so that the reception RoT is maintained as a target RoT to ensure reception performance at all times.

1 is a flowchart illustrating a transmission and reception procedure through a general E-DCH. Here, the terminal transmits the E-DCH, and the base station performs base station scheduling for the terminal.

Referring to FIG. 1, the base station and the terminal perform transmission / reception setup of the E-DCH in step 102. The configuration includes the delivery of messages over a dedicated transport channel. When the E-DCH is configured, the UE informs the BS of scheduling information in step 104. The scheduling information may be a terminal transmission power information that can know the uplink channel information, extra power information that can be transmitted by the terminal, or the amount of data to be transmitted in the buffer of the terminal.                         

The base station that receives the scheduling information from the various terminals schedules the respective terminals while monitoring the scheduling information of the various terminals in step 106. When the base station determines to allow uplink packet transmission to the terminal, the base station transmits a scheduling command including scheduling assignment information to the terminal as shown in step 108. The scheduling allocation information may include an allowed data rate and an allowable timing, or increase / maintenance / decrement information about a previous data rate. The terminal determines the E-DCH Transport Format (E-TF) of the E-DCH to be transmitted in the reverse direction as shown in step 110 by using the scheduling assignment information. ) Transmits the E-TF information to the base station along with the E-DCH packet data.

As shown in step 116, the base station determines whether there is an error in the E-TF information and the E-DCH packet data, and if there is an error in either, NACK information is obtained, and in the case where there is no error, ACK information is obtained. As shown in the process 118, it transmits to the terminal through the ACK / NACK channel. When the ACK information is transmitted in the process 118, transmission of the E-DCH data is terminated, so that new information can be transmitted by the E-DCH. In contrast, when the NACK information is transmitted in the process 118, The UE retransmits the packet data transmitted through the E-DCH at a previous time point through the E-DCH.

A more detailed description of the HARQ method is as follows. The receiver temporarily stores the data in error and combines it with the retransmission of the data to reduce the probability of error. The combining process is called soft combining, and there are two techniques for soft combining, chase combining (CC) and incremental redundancy (IR).

In CC, the sender uses the same format for initial transmission and retransmission. If the first transmission is transmitted in one coded block of m symbols, the same m symbols are also transmitted in retransmission. That is, the same coding rate is applied to the initial transmission and retransmission. The receiver combines the first coded block and the retransmitted coded block, performs a CRC operation using the combined coded block, and checks whether an error occurs.

In IR, the sender uses different formats for initial transmission and retransmission. If n bits of user data are converted into m symbols through channel coding, the transmitting side transmits only some of the m symbols in the first transmission, and sequentially transmits the remaining portions in retransmission. In other words, the coding rates of initial transmission and retransmission are different. The receiving end attaches retransmissions to the back of the initially transmitted coded block, constructs a coding block with a high coding rate, and then executes error correction. In the IR, the first transmission and each retransmission are distinguished by a redundancy version (RV) number. For example, the first transmission is defined as RV 0, the next retransmission as RV 1, the next retransmission as RV 2, etc. The receiving side can use RV information to correctly combine the first transmitted coded block and the retransmitted coded block. have.

Therefore, in order to support the E-DCH operating as described above, a technique for determining the RV so as to obtain the maximum HARQ gain in determining the RV required for the base station to demodulate the E-DCH packet data transmitted by the terminal Needed.

SUMMARY OF THE INVENTION An object of the present invention for meeting the above requirements is to provide a method and apparatus for using an optimized RV parameter set for each data rate or initial transmission coding rate in a system to which HARQ is applied, such as an E-DCH. .

Another object of the present invention is to provide a method and apparatus for determining an RV parameter for each data rate or initial transmission coding rate in a system to which HARQ is applied.

Another object of the present invention is to provide a method and apparatus for setting a RV parameter that a network can use for a terminal and a base station for each data rate or initial transmission coding rate in a system to which HARQ is applied.

In order to achieve the above objects, a preferred embodiment of the present invention provides a redundancy version (RV) parameter for distinguishing initial transmission and retransmission of packet data in a mobile communication system supporting a complex automatic retransmission request for packet data service. In the method of determining,

Acquiring a retransmission number indicating a retransmission number of packet data and transmission format information of the packet data;

Selecting an RV parameter set corresponding to the transmission format information from a plurality of predetermined RV parameter sets;

And determining a RV parameter according to a maximum number of RVs predetermined for the retransmission number and the selected RV parameter set in the selected RV parameter set.

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.

In the present specification, embodiments of the present invention will be described with reference to an enhanced uplink dedicated channel (E-DCH) of a UMTS communication system. In addition, in general, CC can be considered as a special case included in the IR, so in this specification, CC is not mentioned separately.

The HARQ may be classified into a self-decodable method and a non-self-decodable method according to a retransmission version. The self-decodable method uses the same information of the format used for the initial transmission in retransmission, which is prioritized for the transmission of the systematic part of the turbo code at the receiving end. This is to enable decoding on its own. Therefore, when the self-decodable method is used, the receiver can decode the received data without combining the first transmission already buffered and the current retransmission. Since the self-decodable method uses some information in the format used for the first transmission during retransmission, the effective coding rate after combining the initial transmission and the retransmission is relatively high, resulting in soft combining. The coding gain that can be obtained is relatively small. However, even in the case where the first transmission or some retransmissions are not received due to poor channel conditions, decoding can be performed using only the retransmissions currently received.

On the contrary, the non-self decoding method makes it possible to maximize the gain by the redundancy information by using different formats between the initial transmission and the retransmission. Unlike the self-decodable method, the self-decodeable method gives priority to the transmission of non-systematic parts to the retransmission, making it difficult to decode the received data only by the retransmission. Therefore, the receiver can normally decode the received data by combining the initial transmission and the retransmission. Since the self-decoupling method gives priority to transmitting a new format that is not used for the first transmission, the effective coding rate after combining the initial transmission and the retransmissions is relatively low. The code gain that can be obtained by combining is relatively large. However, when the first transmission is not received because of poor channel conditions, decoding is difficult using only the current retransmission.                     

RV according to the present invention is composed of 's' indicating whether the self-decodable / self-decodeable and 'r' representing the redundancy pattern. The redundancy pattern may be used to determine a rate matching parameter that determines which bit to puncture or repeat among the turbo coded bits during HARQ rate matching. Therefore, when the redundancy pattern is changed, the positions of bits that are punctured or repeated among the bits encoded by the turbo code are changed.

At this time, 's = 1' indicates a self-decodable method of giving priority to the transmission of the systematic part, and 's = 0' indicates a self-decoding method of giving priority to the transmission of the non-systematic part. Table 1 below shows an example of RV that can be composed of s and r.

RV s r 0 One 0 One 0 0 2 One One 3 0 One 4 One 2 5 0 2 6 One 3 7 0 3

For example, in Table 1, when 'RV = 4', 's = 1' means self decoding, and since 'r = 2', a second redundancy pattern is used. Therefore, the RV information applied for every transmission of HARQ must be correctly known at the receiving end to decode the data.

On the other hand, in order for the HARQ to operate, there are the following requirements that must be satisfied.                     

[Condition 1] Self-decoding method should always be applied for initial transmission. This enables decoding with only the initial transmission and also enables decoding during soft combining with the retransmission with the self-decoupling method applied.

[Condition 2] In case of low data rate or low initial transmission coding rate, only self-decodable method should be applied. This is because, when the low data rate or the low initial transmission coding rate is applied, the gain that can be obtained in a non-decodeable manner is insignificant. In particular, when the channel environment is poor, such as in the soft handover region, the low data rate or the low initial transmission coding rate may be applied. In this case, when the initial transmission is not received, the decoding can be performed only by retransmission. Only the self-decodable method needs to be considered.

[Condition 3] RV should have an optimized value at every transmission time of HARQ. That is, an RV parameter that can maximize the soft combining gain according to the data rate or the initial transmission coding rate should be defined.

[Condition 4] Allow the network to set the number of RVs as needed. That is, the network can set the number or set of available RVs according to the data rate or initial transmission coding rate or other needs.

The present invention allows the transmitting side and the receiving side to generate or determine RV information of HARQ according to the same rules while satisfying the above conditions, and according to the data rate or initial transmission coding rate of packet data to be transmitted, the RV parameter collection We want to define the sum differently.

The overall concept of the present invention is described below.

The RV value allows the terminal to have an optimized set according to the data rate or initial transmission coding rate of packet data to be transmitted, thereby maximizing the gain due to soft combining of HARQ. That is, in case of transmitting packet data having a low data rate or a low initial transmission coding rate, the RV enables only a self-decodable method (that is, 's = 1'). ] Is satisfied. At this time, 'r' is set to values at which the soft combining gain is maximized under the condition 's = 1'. The RV composed of the above-mentioned 's' and 'r' is referred to as 'RV parameter set 1'. Therefore, 'RV parameter set 1' represents an optimized set of RV parameters that can be self-decoded only.

On the other hand, in the case of transmitting packet data having a high data rate or a high initial transmission coding rate, the RV enables both a self-decodable method and a non-decodable method, thereby maximizing the soft combining gain. At this time, 's' means '0', '1', '0', '1'… in order from lowest value of RV. The values of r are alternately defined, and 'r' is defined as the maximum soft combining gain for the 's' determined as described above. The RV composed of the above-mentioned 's' and 'r' is referred to as 'RV parameter set 2'. Therefore, 'RV parameter set 2' represents an optimized set of RV parameters capable of both a self-decodable method and a self-decodable method.

As described above, the 'RV parameter set 1' and the 'RV parameter set 2' are commonly known in advance between the terminal and the base station. For RV parameter set 1 defined as above, the RV value is determined by Equation 2 below. For RV parameter set 2 defined as above, the RV value is given by Equation 3 Is determined by

In Equation 2 and Equation 3, the 'mod' operation refers to a remainder obtained by dividing x by y when 'x mod y' is used. RSN (Retransmission Sequence Number: RSN) is a value indicating a retransmission number and increases by '1' for each retransmission, and indicates a value set to '0' for initial transmission. That is, the RSN is '0' for initial transmission, '1' for next retransmission, and '2' for next retransmission.

RV_allowed_max_low indicates the maximum number of RVs permitted to the terminal in 'RV parameter set 1', and RV_allowed_max_high indicates the maximum number of RVs permitted to the terminal in 'RV parameter set 2'. The RV_allowed_max_low and RV_allowed_max_high may be informed to the UE through RRC (Radio Resource Control) signaling, and the RNC may inform the base station through Node B Application Part (NBAP) signaling. In addition, the RNC does not signal the values of RV_allowed_max_low and RV_allowed_max_high, and a method of signaling a 'subset of RV parameter set 1' and 'a subset of RV parameter set 2' that is configured with the RV parameters that the RNC wants to allow. The RV_allowed_max_low and RV_allowed_max_high values may be determined as fixed values for both the terminal and the base station.

Equations 2 and 3 use RSN and 'RV = 0' is always set to be self-decodable (i.e., s = 1) for the initial transmission (i.e., RSN = 0). It can always guarantee self-decoding. In Equation 2, RV has a value of 0 to RV_allowed_max_low-1, and in Equation 3, RV has a value of 0 to RV_allowed_max_high-1.

Next, a process of transmitting packet data by determining an RV value will be described with reference to FIG. 2.

In step 200, the terminal receives the ACK / NACK from the base station to determine whether the ACK / NACK for the previous transport packet. If the ACK / NACK information received from the base station is ACK in step 202, 'RSN = 0' of the packet to be transmitted currently is set. If the ACK / NACK information is NACK, the RSN of the packet to be transmitted is greater than the previous value. 1 'increase. In addition, the E-TF of the packet to be transmitted is determined by referring to the scheduling allocation information received from the base station.

In step 204, the UE selects a 'RV parameter set' to which the data rate or initial transmission coding rate corresponding to the determined E-TF belongs. That is, when the data rate or initial transmission coding rate corresponding to the E-TF is smaller than a predetermined value, the 'RV parameter set 1' is selected; otherwise, the data rate or initial transmission coding rate corresponding to the E-TF is selected. If is greater than a predetermined value, the 'RV parameter set 2' is selected. In step 206, the <Equation 2> or <Equation 3> is applied by referring to the RSN value set in step 202, the 'RV parameter set' selected in step 204, and the RV_allowed_max_low or RV_allowed_max_high value signaled from the network. Determine the RV value of the packet to be transmitted currently. In step 208, the packet data is transmitted by applying the determined RV value.

3 shows a flowchart in which a base station receives packet data transmitted by applying the RV determination method.

In step 300 the base station receives the E-TF and RSN value from the terminal, and in step 302 selects the 'RV parameter set' according to the data rate or the initial transmission coding rate corresponding to the received E-TF. That is, when the data rate or initial transmission coding rate corresponding to the E-TF is smaller than a predetermined value, the 'RV parameter set 1' is selected; otherwise, the data rate or initial transmission coding rate corresponding to the E-TF is selected. If is greater than a predetermined value, the 'RV parameter set 2' is selected.

In step 304, Equation 2 or Equation 3 is applied with reference to the RSN value received in step 300, the 'RV parameter set' selected in step 302, and the RV_allowed_max_low or RV_allowed_max_high values signaled from the network. To determine the RV value of the currently received packet. In step 306, the received packet data is decoded by applying the determined RV value.                     

Next, specific examples of the RV determination proposed by the present invention will be described.

In this example, the maximum number of RVs that can be set is eight. Table 2 below shows 'RV parameter set 2', and Table 3 below shows 'RV parameter set 1'.

RV s r 0 One 0 One 0 0 2 One One 3 (= RV_allowed_max_high) 0 One 4 One 2 5 0 2 6 One 3 7 0 3

RV s r 0 One 0 One One One 2 (= RV_allowed_max_low) One 2 3 One 3

As described above, 'RV parameter set 2' indicates a set of RV parameters to be applied when packet data having a high data rate or a high initial transmission coding rate is to be transmitted, and 'RV parameter set 1' has a low data rate. Or a set of RV parameters to be applied when packet data with a low initial transmission coding rate is to be transmitted. The initial transmission coding rate for distinguishing the 'RV parameter set 1' and the 'RV parameter set 2' may be, for example, 0.5. In Table 2, 's' has '1' when RV = 0, and alternately has '0' and '1' whenever RV increases by one. 'r' is set to values such that the soft combining gain is maximized whenever the RV value increases by one with respect to the above-defined 's'. The 'r' can be obtained through the experiment to obtain the optimum value.

In Table 3, 's' always has '1' regardless of RV. That is, packet data having a low data rate or a low initial transmission coding rate is always self-decodable. 'r' is set to values such that the soft combining gain is maximized whenever the RV value increases by one with respect to 's' in Table 3. In Tables 2 and 3, it is assumed that 'r' is set to have an optimal value when 's' is set.

In this case, it is assumed that the RV_allowed_max_high is set to '3' in the 'RV parameter set 2', and the RV_allowed_max_low is set to '2' in the 'RV parameter set 1'. The RV_allowed_max_high and RV_allowed_max_low are values signaled to the terminal and the base station, respectively.

First, when the UE intends to transmit packet data having a high data rate or a high initial transmission coding rate, since 'RV parameter set 2' is applied, refer to Table 2 above. Applying Equation 3 for the initial transmission (RSN = 0), 'RV = 0' as 'RV = RSN mod RV_allowed_max_high = 0 mod 3 = 0'. Applying Equation 3 for retransmission (RSN = 1), 'RV = 1' as 'RV = RSN mod RV_allowed_max_high = 1 mod 3 = 1'. Then, when Equation 3 is applied to retransmission (RSN = 2), 'RV = 2' as 'RV = RSN mod RV_allowed_max_high = 2 mod 3 = 2'. Then, when the above Equation 3 is applied to the retransmission (RSN = 3), 'RV = 0' as 'RV = RSN mod RV_allowed_max_high = 3 mod 3 = 0'. Therefore, RV has three values of 0, 1, and 2.

On the other hand, when the UE intends to transmit packet data having a low data rate or a low initial transmission coding rate, 'RV parameter set 1' is applied, so refer to Table 3 above. Applying Equation 2 for the initial transmission (RSN = 0), 'RV = 0' as 'RV = RSN mod RV_allowed_max_high = 0 mod 2 = 0'. Applying Equation 2 above for retransmission (RSN = 1), 'RV = 1' as 'RV = RSN mod RV_allowed_max_high = 1 mod 2 = 1'. Then, when Equation 2 is applied to the retransmission (RSN = 2), 'RV = 0' as 'RV = RSN mod RV_allowed_max_high = 2 mod 2 = 0'. Therefore, RV has two values, 0 and 1.

Next, a transmission apparatus of a terminal to which the RV determination method proposed by the present invention is applied will be described with reference to FIG. 4. For convenience of description, channels other than the E-DCH are omitted.

Referring to FIG. 4, the terminal receives scheduling allocation information 402 from the base station. The scheduling allocation information 402 may instruct the terminal to increase / maintain / decrease the maximum allowable data rate, or may include a maximum allowable data rate and a timing at which transmission is allowed. The E-DCH rate determiner 404 of the terminal determines the E-DCH rate by referring to the scheduling allocation information 402 and the amount of E-DCH data of the E-DCH data buffer 400. The determined E-DCH transmission rate is applied to the E-DCH transmission controller 406 and the RV parameter determiner 419, respectively.                     

The RV parameter determiner 419 determines the RSN by determining the ACK / NACK 417 received from the base station, selects an 'RV parameter set' from the determined E-DCH transmission rate, and allows the RNC to allow the UE to use the maximum. The RV parameter is determined in consideration of the number of RVs, the RSN, and the 'RV parameter set'. A detailed procedure of determining the RV parameter follows the RV determination method of FIG. 3. The RV parameter determiner 419 applies the RSN value to the E-DCH transmission controller 406 and applies the RV parameter to the physical channel HARQ / rate matching unit 412.

The E-DCH transmission controller 406 determines the E-DCH transmission format from the E-DCH transmission rate and applies it to the E-DCH packet transmitter 408. At this time, the E-DCH transmission controller 406 refers to the RSN value received from the RV parameter determiner 419 and transmits the E-DCH data of the E-DCH data buffer 400 in the case of the initial transmission. The E-DCH packet transmitter 408 is controlled to reconstruct and transmit previously sent E-DCH data. The E-DCH packet transmitter 408 fetches a specified amount of data from the E-DCH data buffer 400 according to the E-DCH transmission format, and then constructs the E-DCH packet data of the appropriate format.

The E-DCH packet data is encoded via the E-DCH data channel encoder 410 and then rate matched via the HARQ / rate matcher 412. In this case, the HARQ / rate matcher 412 performs a HARQ operation by determining a puncturing or repetition pattern with reference to the RV parameter received from the RV parameter determiner 419. The data generated by the HARQ / rate matcher 412 is interleaved via an interleaving / physical channel mapper 414 and mapped to physical channel data. The physical channel data is spread by the channel spreader 416 in a channel code C _{e_dpdch} allocated to an enhanced dedicated physical data channel (E-DPDCH), which is a physical data channel for the E-DCH.

The E-DCH transmission controller 406 generates an identifier indicating an E-TF (E-TF Identifier: hereinafter referred to as E-TFI) from the determined E-DCH transmission rate and receives an RSN received from the RV parameter determiner 419. HARQ control information is generated with reference to the value. The E-DCH control information including the E-TFI and the HARQ control information is encoded by the E-DCH control information channel encoder 418 and the physical control channel for the E-DCH by the physical channel mapper 420. It is mapped to physical channel data of an enhanced dedicated physical control channel (E-DPCCH) and then spread by the spreader 422 to the channel code C _{e_dpcch} allocated for the E-DPCCH. The E-DCH control information may further include information for scheduling in addition to the E-TFI and the HARQ control information. The data of the E-DPDCH and the E-DPCCH generated as described above are multiplexed by the multiplexer 424 and then transmitted through the scrambler 426.

Next, a receiver of a base station to which the RV determination method proposed by the present invention is applied will be described with reference to FIG. 5. For convenience of description, channels other than the E-DCH are omitted.

Referring to FIG. 4, the received signal of the base station is divided into I / Q-branched signals by the demodulator 504 through the inverse scrambler 500 and the channel compensator 502. E-DPCCH and E-DPDCH data may be obtained by despreading the I / Q-branch signals into channel codes C _{e_dpcch} and C _{e_dpdch} of a physical channel to be decoded by the spreaders 506 and 514, respectively.

The physical channel demapper 508 extracts coded control information of a terminal to be received through the E-DPCCH data output from the despreader 506 and provides the same to the E-DCH control information channel decoder 510. . The E-DCH channel decoder 510 decodes the coded control information to extract the E-TFI and RSN values and applies them to the RV parameter determiner 512. The RV parameter determiner 512 selects an 'RV parameter set' from the E-TFI, and determines the RV parameter in consideration of the RSN value and the maximum number of RVs allowed to the terminal. A detailed procedure of determining the RV parameter follows the RV determination method of FIG. 4.

The E-DPDCH data output from the despreader 514 is passed through a physical channel de-mapping and deinterleaver 516 and a physical channel HARQ / rate de-matcher 518 including HARQ operation. 520 is applied. In this case, the physical channel HARQ / rate reverse matcher 518 refers to the E-TFI applied from the E-DCH control information channel decoder 510 and the RV parameter applied from the RV parameter determiner 512 to perform the rate reverse matching. Do this. The rate de-matched data is decoded by the E-DCH data channel decoder 520 and finally output as E-DCH packet data.

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. For example, in the present specification, a method of encoding and decoding E-TFI information, HARQ-related information, and scheduling information has been described. However, the operation and structure may be applied to other input information. 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.

As described above, in the present invention, in a system to which HARQ is applied, such as an E-DCH, an RV parameter set optimized for each data rate or initial transmission coding rate is defined and used. In addition, the RV is determined for each data rate or initial transmission coding rate of packet data to be transmitted.

This ensures that the initial transmission data of the HARQ always guarantees a self decodable property, and always guarantees a self decodable property for packet data having a low data rate or a low initial transmission coding rate. In addition, by using the optimized RV parameter set, the maximum HARQ gain can be obtained, and the network can set the RV for each data rate or initial transmission coding rate.

Claims (7)

A method of determining a redundancy version (RV) parameter for distinguishing between initial transmission and retransmission of packet data in a mobile communication system supporting a complex automatic retransmission request for packet data service, Acquiring a retransmission number indicating a retransmission number of packet data and transmission format information of the packet data; Selecting an RV parameter set corresponding to the transmission format information from a plurality of predetermined RV parameter sets; Determining an RV parameter according to the retransmission number and a maximum number of RVs predetermined for the selected RV parameter set in the selected RV parameter set. The method according to claim 1, wherein the RV parameter is And a 's' bit indicating whether or not the packet data can be decoded and a 'r' value indicating a redundancy pattern. The method of claim 2, wherein the 'r' value, And a value representing a redundancy pattern maximizing soft combining gain according to the value of 's'. The method of claim 1, wherein the plurality of RV parameter sets, First RV parameter sets including RV parameters for packet data having a low data rate and a low initial transmission coding rate, Said second RV parameter sets comprising RV parameters for packet data having a high data rate and a high initial transmission coding rate. 5. The method of claim 4, wherein the first RV parameter sets comprise RV parameters that satisfy the following equation. RV = RSN mod RV_allowed_max_low Where RSN is the retransmission number and RV_allowed_max_low is the maximum number of RVs determined for the first RV parameter set. 5. The method of claim 4, wherein the second RV parameter sets comprise RV parameters that satisfy the following equation. RV = RSN mod RV_allowed_max_high Where RSN is the retransmission number and RV_allowed_max_high is the maximum number of RVs determined for the second RV parameter set. The method of claim 4, wherein the initial transmission coding rate, Said method, characterized in that 0.5.

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