KR20020006825A - Apparatus for receiving frame with multi-length and method thereof in mobile communication system - Google Patents

Abstract

PURPOSE: An apparatus and method for receiving a multi length frame in a mobile communication system is provided to improve a frame error rate by detecting a frame with an inserted length in case of receiving the multi length frame and replacing an interval of the detected frame length with a setting value. CONSTITUTION: The first frame processor has the first deinterleaver(419) for deinterleaving a received message frame by the first frame length unit, the first decoder(421) for decoding the message frame deinterleaved in the first deinterleaver(419), and the first error detector(423) for detecting an error of the message frame decoded in the first decoder(421). A frame replacer includes a controller(425) for being driven when the first frame is detected and generating a driving signal at an interval in which the first frame is detected and a replacer(427) for being driven at a corresponding interval when the driving signal generated in the controller(425) is received and replacing a frame interval of the detected first frame length with certain data. The second frame processor has the second deinterleaver(431) for deinterleaving the received message frame by the second frame length unit, the second decoder(433) for decoding the message frame deinterleaved in the second deinterleaver(431), and the second error detector(435) for detecting an error of the message frame decoded in the second decoder(433).

Description

Apparatus and method for receiving multi-length frame in mobile communication system {APPARATUS FOR RECEIVING FRAME WITH MULTI-LENGTH AND METHOD THEREOF IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a receiving apparatus and method of a mobile communication system, and more particularly, to a receiving apparatus and method at a receiving end when a multi-length frame is transmitted in an intermix mode.

In the intermix mode, when there is a request for a 5ms frame in a higher layer, a 5ms frame is punctured in a 20ms frame instead of a 5ms frame, and a 5ms frame is loaded instead. How to send.

Currently, the apparatus and method for receiving a multi-length frame in an intermix mode decode a 5 ms frame separately when a 5 ms frame is detected through a cyclic redundancy check (CRC) error detector, and a 5 ms frame has 5 ms frame data therein. It is decrypted with it. This method has a problem that the frame error rate of the 20ms frame is too high because 5ms frame in the 20ms frame is recognized as an error.

Hereinafter, a structure of a transmitter and a receiver in the forward and reverse directions in the intermix mode according to the prior art will be described.

1 is a diagram illustrating a configuration of a forward transmitting end of a general code division multiple access mobile communication system.

Referring to FIG. 1, the CRC generators 111 and 112 perform a function of adding a CRC to a rear end of the 20ms and 5ms information bits that are input so that the receiver can determine the quality (error) of the frame. In this case, the CRC generators 111 and 112 generate and add CRCs of different bits according to a radio configuration (RC) and a data rate. Tail bit encoders 113 and 114 generate tail bits necessary for terminating an error correction code, and generate 8-bit tail bits to correspond to the corresponding CRCs. In addition to the output of the generators 111 and 112, it outputs.

The encoders 115 and 116 input and encode the outputs of the corresponding tail bit generators 113 and 114, respectively. In this case, the encoding rate uses different values according to the RC and the data rate. Examples of the coder include a convolutional coder and a turbo coder.

The symbol repetition 117 and 118 take output coded data of the corresponding encoders 115 and 116 as inputs, respectively, and repeatedly output a predetermined number of times according to a given rule. At this time, the repeaters 117 and 118 repeatedly output at different times according to RC and data rate. Symbol punctures 119 and 120 input the outputs of the corresponding repeaters 117 and 118, respectively, and puncture the output according to a given pattern. In this case, the puncturers 119 and 120 do not puncture when the frame is 5ms, and when punctured by 20ms, the puncturers 119 and 120 are punctured in different patterns according to RC and data rate.

The interleavers 121 and 122 interleave and output the output data from the corresponding punchers 119 and 120, respectively. That is, the interleavers 121 and 122 change the bit arrangement in the frame on a frame-by-frame basis of the message, thereby improving immunity to burst errors.

An intermixer 123 merges the 5 ms and 20 ms frames output from the interleaver 121 and 122. In the merging method, when a 5ms frame is generated while a 20ms frame is being transmitted, a 5ms frame is punctured in a 20ms frame and a 5ms frame is loaded instead.

The signal mapping block 125 performs a function of converting a signal of a transmission signal. That is, the signal converter 125 converts the transmission signal into -1 if the transmission signal has a logic of 1, and +1 if the transmission signal has a logic of 0. An orthogonal codegenerator 129 generates an orthogonal code for use in forward channel division. The orthogonal code may be a Walsh code or a quasi-orthogonal code. The multipliers 127 and 131 mix the signals of the I channel and the Q channel corresponding to the orthogonal codes output from the orthogonal code generator 129 and output spread signals of the forward link. The modulator 133 receives QPSK-modulated signals output from the multipliers 127 and 131 and outputs them.

2 is a diagram illustrating a configuration of a reverse transmitting end of a general code division multiple access mobile communication system. As shown in FIG. 2, the configuration of the reverse transmitter is similar to that of the forward transmitter.

Referring to FIG. 2, the CRC generators 211 and 212 add a cyclic redundancy check (CRC) to the back end of the 20ms and 5ms information bits inputted to determine the quality (error) of the frame at the receiver. Perform the function. At this time, the CRC generators 211 and 212 generate and add CRCs of different bits according to RC and data rate. Tail bit encoders 213 and 214 generate tail bits necessary for terminating an error correction code, and generate tail bits of 8 bits to respectively correspond to the corresponding CRCs. In addition to the outputs of the generators 211 and 212, it is output.

The encoders 215 and 216 input, encode, and output the corresponding outputs of the tail bit generators 213 and 214, respectively. In this case, the encoding rate uses different values according to the RC and the data rate, and the encoders used include a convolutional encoder and a turbo encoder.

The symbol repetition 217 and 218 take as input the output encoded data of the corresponding encoders 215 and 216, respectively, and repeatedly output a predetermined number of times according to a given rule. In this case, the repeaters 217 and 218 are repeatedly output at different times according to RC and data rate. Symbol punctures 219 and 220 input the outputs of the corresponding repeaters 217 and 218, respectively, and puncture the output according to a given pattern. In this case, the puncturers 219 and 220 do not puncture when the frame is 5ms, and when the frame is 20ms, the puncturers 219 and 220 are punctured in different patterns according to RC and data rate.

The interleavers 221 and 222 interleave and output the output data from the corresponding punchers 219 and 220, respectively. That is, the interleavers 221 and 222 change the bit arrangement in the frame on a frame-by-frame basis of the message to improve resistance to burst errors.

An intermixer 223 merges the 5 ms and 20 ms frames output from the interleaver 221 and 222. In the merging method, when a 5ms frame is generated while a 20ms frame is being transmitted, a 5ms frame is punctured in a 20ms frame and a 5ms frame is loaded instead.

The signal mapping block 225 converts a signal of the transmission signal. That is, the signal converter 225 converts the transmission signal into -1 if the transmission signal has a logic of 1, and +1 if the transmission signal has a logic of 0. Quadrature spreader 227 generates and outputs a Walsh code. The multiplier 229 receives a Walsh code generated by the quadrature spreader 227 and outputs the converted transmission signal output from the signal converter 225. The complex multiplier 231 inputs a PN code (Pseudo Random Noise sequence) PNi and PNq output from a PN sequence generator (not shown) to generate and output spread signals of corresponding I and Q channels, respectively. .

3 is a diagram illustrating a configuration of a receiving end of a general code division multiple access mobile communication system.

Referring to FIG. 3, the PN despreader 311 outputs the received signal by despreading the PN. The Walsh despreader 315 despreads the signal of the corresponding channel among the signals output from the PN despreader. The channel estimator 313 extracts a pilot signal from a signal output from the PN despreader, estimates a channel, and generates and outputs a conjugated signal for channel compensation with the extracted pilot signal. The multiplier 317 multiplies the output of the Walsh despreader 315 by the conjugate signal of the channel estimator 313 and outputs a channel compensated signal. The first deinterleaver 319 changes the bit array in the frame in units of 5ms at the transmitter and converts the transmitted signal into the original array. The decoder 321 decodes and outputs the output of the first deinterleaver 319 as an input. The first error detector 323 receiving the decoded received signal receives the output of the 5ms frame decoder 321 as an input and performs a CRC error check to check whether a frame error has occurred. At this time, the result signal output from the first error detector 323 is output as a true signal (True, 1) and a false signal (False, 0). When the value of the first C error detector 323 is determined to be true, the output value of the decoder 321 becomes the final output value of a 5 ms frame.

The 20 ms buffer 325 stores an input value of the multiplier 317 as an input and stores every frame of 5 ms in length until the 20 ms frame is in length. The second deinterleaver 327 changes the bit array in the frame in units of 20 ms frame and transmits the transmitted signal to the original array. The decoder 329 decodes and outputs the output of the second deinterleaver 327 as an input. The second error detector 331 receives the output of the 20ms frame decoder 329 as an input and performs a CRC error check to check whether a frame error has occurred. At this time, the result signal output from the second error detector 331 is output as a true signal (True, 1) and a false signal (False, 0). When the value of the second error detector 331 is determined to be true, the output value of the decoder 329 becomes the final output value of the 20 ms frame.

FIG. 4A shows a frame error rate when the decoding method as shown in FIG. 3 is used. 4A illustrates a result of decoding a 20 ms frame in an environment without noise. Here, the horizontal axis represents the position where the 5 ms frame is inserted, and the vertical axis represents the frame error rate (%). As shown, in the case of RC4 and RC5, the frame error rates are 98% and 24 to 45%, respectively. Despite experimental results assuming no noise, RC4 and RC5 show very high frame error rates. In the case of RC3, when the 5ms frame is punctured at the front of the 20ms frame, the frame error rate is much higher than when the other parts are punctured. In order to look at the results for the RC3 in more detail, the results of the experiment in the noise environment of 6dB is shown in FIG. It can be seen that the frame error rate of 1% is obtained only when -16 ~ 17dB is reached. This is not a satisfactory result, it can be seen that when applying the present invention to be described later, the performance difference of 6 ~ 7dB.

Accordingly, an object of the present invention is to provide an apparatus and method for detecting a frame having an inserted length when receiving a frame having multiple lengths, and improving a frame error rate by replacing the detected frame length with a setting value.

It is still another object of the present invention to provide an apparatus and method for efficiently decoding frames having different lengths when receiving frames having multiple lengths.

The apparatus of the present invention for achieving the above object; A frame receiving apparatus of a mobile communication system for receiving a message of a multi-frame in which first and second frames having at least two frame lengths are intermixed and transmitted, wherein the received multi-frame message is received in the first frame section. A first frame processor which decodes and generates a detection signal of the first frame, and is driven by the first frame detection signal, and predetermines data of a section in which the detected first frame is located in the received message frame; And a second frame processor for receiving a message frame output from the frame replacer and a second frame processor for decoding the received message in the second frame section.

The method of the present invention for achieving the above object; A method of receiving a frame of a mobile communication system in which a first frame and a second frame having at least two frame lengths are intermixed and transmitted, and the second frame has an integer multiple of the first frame. The method may include receiving the message frame, decoding the received message frame in the first frame period, generating a presence / absence detection signal of the first frame, and receiving the received message when the first frame detection signal is generated. Receiving a message frame in which data of a section in which the detected first frame is located is replaced with predetermined data in a frame, and a message frame in which the section in which the detected first frame is located is replaced with predetermined data, and receiving the second frame And a process of decoding the received message in a section.

1 is a diagram illustrating a configuration of a forward transmitting end of a general code division multiple access mobile communication system.

2 is a diagram illustrating a configuration of a reverse transmitting end of a general code division multiple access mobile communication system.

3 is a diagram illustrating a configuration of a receiving end of a general code division multiple access mobile communication system.

Figure 4a is a diagram of the experimental results when using the conventional method in the noise-free environment for multi-length frame transmission.

Figure 4b is a diagram showing the results of the experiment when decoding using the conventional method for RC3 in a noise environment of 6dB in multi-length frame transmission and when applying the present invention.

5 is a diagram illustrating a configuration of a receiving end of a code division multiple access mobile communication system according to an embodiment of the present invention.

6 is a flowchart illustrating a decoding process of a 20ms frame according to an embodiment of the present invention.

7 is a view showing an experimental result comparing the frame error rate of the existing method for RC3 in the intermix mode and the method to which the present invention is applied.

8 is a view showing an experimental result comparing the frame error rate of the conventional method for RC4 in the intermix mode and the method to which the present invention is applied.

9 is a view showing an experimental result comparing the frame error rate of the conventional method for RC5 in the intermix mode and the method to which the present invention is applied.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

FIG. 5 is a diagram illustrating a configuration of a receiving end of a code division multiple access mobile communication system according to an embodiment of the present invention. In particular, FIG.

First, the frame receiving apparatus of the receiving end receives a multi-frame message in which first and second frames are intermixed and transmitted, and decodes the received message in the first frame section to generate a detection signal of a first frame. A first frame processor configured to be driven by the first frame detection signal, a frame replacer for replacing data of a section in which the detected first frame is located in the received message frame with predetermined data, and an output from the frame replacer And a second frame processor which receives the message frame and decodes in the second frame period. Here, the first frame processor may include a first deinterleaver 419 for deinterleaving the received message frame in units of a first frame length, and a decoded message frame deinterleaved by the first deinterleaver 419. A first decoder 421 and a first error detector 423 which performs error detection of the message frame decoded by the first decoder 421. The frame replacer starts driving when the first frame is detected, and receives the driving signal generated by the controller 425 and the driving signal generated by the controller 425 when the first frame is detected. Accordingly, it consists of a substituent 427 for driving in the corresponding section to replace the detected frame section of the first frame length with predetermined data. The second frame processor may further include a second deinterleaver 431 for deinterleaving the received message frame in units of a second frame length, and a second decoder for decoding the message frame deinterleaved by the deinterleaver 431. 433 and a second error detector 435 which performs error detection of the message frame decoded by the second decoder 433.

The PN despreader 411 outputs the PN despreader by inputting the received signal. The Walsh despreader 415 despreads to output a signal of a corresponding channel among the signals output from the PN despreader 411. The channel estimator 413 estimates and outputs a channel based on the signal output from the PN despreader 411. The multiplier 417 multiplies the signal output from the Walsh inverse spreader 415 and the signal output from the channel estimator 413. The first deinterleaver 419 deinterleaves the transmitted signal by changing the bit arrangement in the frame in units of 5ms frame at the transmitter and outputs the signal to the first decoder 421. The first decoder 421 inputs a signal output from the first deinterleaver 419, decodes the input signal, and outputs the decoded signal to the first error detector 423. The first error detector 423 inputs a signal output from the first decoder 421 and checks whether a frame error has occurred by performing a CRC error check on the input signal. Here, the result signal output from the first error detector 423 is output as a true signal (True, 1) and a false signal (False, 0). When the output signal of the first error detector 423 is determined to be a true signal, the output value of the first decoder 421 becomes a final output value of a 5 ms frame. The controller 425 receives a test result of whether a 5 ms frame is detected, and controls the substituent 427 to operate only when the 5 ms frame is detected. In order to determine whether a 5 ms frame is detected, the controller 425 may use a re-encoded symbol error rate and the re-encoded in addition to the cyclic redundancy check (CRC) error detector described above. It is possible to use a combination of symbol error rate and the CRC.

The substituent 427 operates only when the output signal of the first error detector 423 is determined to be a true signal under the control of the controller 425, that is, only when the 5 ms frame is detected. The symbol value as much as 5ms frame length is replaced with a setting value, for example, '0' and output. The buffer 429 inputs the output of the substituent 427 when the output signal of the first error detector 423 is determined to be a true signal, and determines that the output signal of the first error detector 423 is a false signal. When input, the output of the multiplier 417 is input and stored. The second deinterleaver 431 deinterleaves the transmitted signal by changing the bit arrangement in the frame in units of 20ms frame at the transmitter and outputs the signal to the second decoder 433. The second decoder 433 inputs an output signal of the second deinterleaver 431, decodes the input signal, and outputs the decoded signal to the second error detector 435. The second error detector 435 inputs the decoded received signal output from the second decoder 433 and performs a CRC error check to check whether a frame error has occurred.

6 is a flowchart illustrating a decoding process of a 20ms frame according to an embodiment of the present invention.

First, when the received signal is input in step 611, there is no frame stored in the buffer 429, so the count variable "5ms FRAME COUNT" counting the number of 5ms frames stored in the buffer 429 is 0. Its initial value is set (5ms FRAME COUNT = 0). In step 613, the count variable “5ms FRAME COUNT” is increased and the process proceeds to step 615. If a 5 ms frame is not detected by the first error detector 423 in step 615, the received 5 ms frame, that is, a 5 ms frame of the received signal before decoding, is stored in the buffer 429 in step 617. If the output signal of the first error detector 423 is a true signal, that is, if the decoded received signal of the first decoder 421 is detected as a 5 ms frame, the data corresponding to the decoded 5 ms frame in step 619. Is changed to a set value '0' and stored in the buffer 429. If the number of 5ms frames stored in the buffer 429 is four, that is, 20ms frames are formed in step 621 (5ms FRAME COUNT = 4), the second deinterleaver stores the 20ms frames stored in the buffer 429. After interleaving at 431, the second decoder 433 is used to decode.

As described above with reference to FIG. 6, when the 5ms frame is normally decoded in the intermix mode, the frame error rate is reduced by changing the length corresponding to the 5ms frame in the 20ms frame to '0' and inserting the frame again into the 20ms frame. Hereinafter, a frame error rate when receiving a frame according to an embodiment of the present invention is shown.

7 is a diagram showing an experimental result comparing the frame error rate of the conventional method for RC3 in the intermix mode and the method to which the present invention is applied.

Conventionally, a 20ms frame transmitted by a transmitter in an intermix mode was decoded with 5ms of data. On the contrary, in the embodiment of the present invention, when the 5ms frame received in the intermix mode is determined to be a true signal by the first error detector 423, 5ms in the 20ms frame transmitted by the transmitter are changed to '0' and thus 20ms. 5 ms in the frame is changed to 0 to be decoded. As shown, a difference of about 2 dB occurs between the frame error rate according to the embodiment of the present invention and the Ec / Io value satisfying the frame error rate of 1% in the frame error rate according to the prior art. In this case, it can be seen that a frame error rate of 1% is obtained when Ec / Io = -22 dB, and there is almost no performance difference according to the position of a 5 ms frame inserted in the intermix mode.

8 is a diagram showing an experimental result comparing the frame error rate of the conventional method for RC4 in the intermix mode and the method to which the present invention is applied.

As described above with reference to FIG. 7, in the prior art, when decoding a 20 ms frame transmitted from a transmitter in an intermix mode, 5 ms data is decoded. According to an embodiment of the present invention, when a received 5ms frame is determined to be a true signal through the first error detector 423 and detected, a 5ms in a 20ms frame transmitted by a transmitter in the intermix mode is changed to '0', and thus 20ms frame. The 5 ms in it is decoded by changing to zero. 8 illustrates a frame error rate of a received frame according to the prior art and an error rate of a received frame according to an embodiment of the present invention. As illustrated, an Ec / Io value satisfying the frame error rate of 1% is shown in the related art. There is a difference of about 2dB between the inventions, and compared to the frame error rate of 98% for 20ms frame decoding that includes 5ms frame data in the conventional intermix mode, performance improvement in terms of frame error rate is found. have. In addition, it can be seen that the position of the 5ms frame does not affect the performance with a frame error rate of 1% at Ec / Io = −21 dB.

9 is a diagram showing an experimental result comparing the frame error rate of the conventional method for RC5 in the intermix mode and the method to which the present invention is applied.

As described above with reference to FIG. 7, the conventional technology decodes 5ms of data when decoding a 20ms frame in an intermix mode. In the method according to an embodiment of the present invention, when the received 5ms frame is detected as a true signal through the first error detector 423, 5ms in the 20ms frame transmitted by the transmitter in the intermix mode are changed to '0'. Therefore, 5ms in a 20ms frame is changed to 0 to be decoded. As shown, a difference of about 2 dB occurs between the frame error rate according to the embodiment of the present invention and the Ec / Io value satisfying the frame error rate of 1% in the frame error rate according to the prior art, and includes 20 ms including data of 5 ms frame. Compared with the frame error rate of 25 ~ 45% when decoding the frame, it can be seen that the performance improvement occurs in the frame error rate. In addition, a frame error rate of 1% can be obtained at Ec / Io = -19.5dB, and it can be seen that there is almost no performance difference according to the position of a 5ms frame.

As described above, when receiving a frame having a different length when receiving a frame transmitted in an intermix mode, each frame having a different length is separately decoded and has a different length inserted in the intermix mode. Decoding is performed by changing the length of the frame to '0' to improve the performance of the frame error rate.

Claims (34)

A frame receiving apparatus of a mobile communication system for receiving a message of a multi-frame in which the first and second frames having at least two frame lengths are intermixed and transmitted, A first frame processor for decoding the received multi-frame message in the first frame section and generating a detection signal of the first frame; A frame replacer driven by the first frame detection signal and replacing data of a section in which the detected first frame is located with predetermined data in the received message frame; And a second frame processor configured to receive the message frame output from the frame replacer and to decode the received message in the second frame period. The method of claim 1, The first frame processor; A first deinterleaver for deinterleaving the received message frame by a first frame length unit; A first decoder to decode the deinterleaved message frame; And a first error detector configured to perform error detection of the decoded message frame. The method of claim 2, The first error detector is characterized in that the CRC error detector. The method of claim 1, The frame substituent; A controller which starts driving when the first frame is detected and generates a driving signal in a section in which the first frame is detected; And a substituent configured to receive a driving signal generated by the controller and drive the corresponding section to replace the detected frame section of the first frame length with predetermined data. The method of claim 4, wherein The substituent; And a buffer for storing the decoded first length frame and the first length received frame before the decode. The method of claim 1, And the predetermined data is zero. The method of claim 1, The second frame processor; A second deinterleaver for deinterleaving the received message frame by a second frame length unit; A second decoder for decoding the deinterleaved message frame; And a second error detector configured to perform error detection of the decoded message frame. The method of claim 7, wherein The second error detector is characterized in that the CRC error detector. The method of claim 1, Wherein the first frame is 5 ms, and the second frame is 20 ms. Receive a multi-frame message in which the first and second frames having at least two frame lengths are intermixed and transmitted, wherein the second frame is an integer multiple of the first frame. In the receiving device, A frame despreader for receiving the message frame and despreading the received message frame; A first frame processor configured to receive the despread message frame and to decode the received message frame in the first frame section and to generate a detection signal of the first frame; A frame replacer driven by the first frame detection signal and replacing data of a section in which the detected first frame is located in the received message frame with predetermined data; And a second frame processor configured to receive the message frame output from the frame replacer and to decode the received message in the second frame period. The method of claim 10, The frame despreader; A PN despreader for PN despreading the received message frame; And a Walsh despreader for Walsh despreading the PN despreaded message frame. The method of claim 10, The first frame processor; A first deinterleaver for deinterleaving the despread message frame in units of a first frame length; A first decoder to decode the deinterleaved message frame; And a first error detector configured to perform error detection of the decoded message frame. The method of claim 12, The first error detector is characterized in that the CRC error detector. The method of claim 10, The frame substituent; A controller which starts driving when the first frame is detected and generates a driving signal in a section in which the first frame is detected; And a substituent configured to receive a driving signal generated by the controller and drive the corresponding section to replace the detected frame section of the first frame length with predetermined data. The method of claim 10, And the predetermined data is zero. The method of claim 10, The second frame processor; A second deinterleaver for deinterleaving the despread message frame in units of a second frame length; A second decoder for decoding the deinterleaved message frame; And a second error detector configured to perform error detection of the decoded message frame. The method of claim 16, The second error detector is characterized in that the CRC error detector. The method of claim 10, Wherein the first frame is 5 ms, and the second frame is 20 ms. A method of receiving a frame of a mobile communication system in which a first frame and a second frame having at least two frame lengths are intermixed and transmitted, and the second frame has an integer multiple of the first frame. In Receiving the message frame, decoding the received message frame in the first frame section, and generating a detection presence signal of the first frame; Replacing the data of the section in which the detected first frame is located with predetermined data when the first frame detection signal is generated; And receiving a message frame in which the section in which the detected first frame is located is replaced with predetermined data, and decoding the received message in the second frame section. The method of claim 19, Generating the first frame detection signal; Deinterleaving the received message frame in units of a first frame length; Decoding the deinterleaved message frame; Performing error detection of the decoded message frame. The method of claim 20, The error detection is characterized in that the CRC error detection. The method of claim 19, And the predetermined data is zero. The method of claim 19, Decoding the received message in the second frame period; Deinterleaving the received message frame in units of a second frame length; Decoding the deinterleaved message frame; Performing error detection of the decoded message frame. The method of claim 23, wherein The error detection is characterized in that the CRC error detection. The method of claim 19, Wherein the first frame is 5 ms, and the second frame is 20 ms. A receiving method of a code division multiple access communication system for receiving a message of multiple frames in which first and second frames having at least two frame lengths are intermixed and transmitted, Despreading the received message frame; Receiving the despread message frame, decoding the received message frame in the first frame period, and generating a detection signal of the first frame; Replacing the data of the section in which the detected first frame is located with predetermined data when the first frame detection signal is generated; And receiving a message frame in which the section in which the detected first frame is located is replaced with predetermined data, and decoding the received message in the second frame section. The method of claim 26, Despreading the received message frame; Despreading the received message frame by PN; And Walsh despreading the PN despreaded message frame. The method of claim 26, Generating the first frame detection signal; Deinterleaving the received message frame in units of a first frame length; Decoding the deinterleaved message frame; Performing error detection of the decoded message frame. The method of claim 28, The error detection is characterized in that the CRC error detection. The method of claim 26, And the predetermined data is zero. The method of claim 26, When the first frame detection signal is generated, replacing data of a section in which the detected first frame is located with predetermined data in the received message frame; And storing the decoded first length frame and the first length received frame before the decoding in a buffer. The method of claim 26, Decoding the received message in the second frame period; Deinterleaving the received message frame in units of a second frame length; Decoding the deinterleaved message frame; Performing error detection of the decoded message frame. 33. The method of claim 32, The error detection is characterized in that the CRC error detection. The method of claim 26, Wherein the first frame is 5 ms, and the second frame is 20 ms.