KR20020054454A - Method for rate Indication and rate decision of High-speed Data Channel in Mobile Communication System - Google Patents

Abstract

PURPOSE: A method for indicating a rate of a high-speed data channel in a mobile communication system and a method for deciding the rate are provided to enable a receiving end not to perform blind detection by making a transmitting end send a variable rate indicator related to the next frame in case of using a turbo encoder, thereby reducing overhead due to the detection. CONSTITUTION: A frame quality indicator is inserted into channel bits(301). An encoder after-edge bit is inserted into a turbo encoder(302). The turbo encoder encodes the inserted encoder after-edge bit(303). A symbol repeater repeatedly performs symbol repetition with encoded data and a symbol puncturing part repeatedly performs puncturing(304,305). A block interleaver interleaves the repeated and punctured symbols and transmits the modulated system to a receiving end(306).

Description

Rate indication method and rate determination method of high data rate channel in mobile communication system {Method for rate Indication and rate decision of High-speed Data Channel in Mobile Communication System}

The present invention relates to a rate indicating method and a rate determining method of a high speed data channel in a mobile communication system. In particular, when a turbo decoder is used in an IMT-2000 system, variable rate identification information is inserted and transmitted. The present invention relates to a rate indicating method and a rate determining method of a high speed data channel in a mobile communication system in which a receiver for setting a decoder for a next frame using the variable rate identification information.

Existing IS-95 family (or JSTD-008) CDMA systems focus on voice services and perform low-rate data services. In the IS-95 family CDMA system, when data is transmitted from a transmitting end, the data rate is changed according to the quantity of data, which is called a variable rate service. In order to perform the variable rate service as described above, a data rate for a frame received at the receiving end must be determined.

In addition, both the forward and reverse links of the IS-95 family perform variable rate services. In the IS-95 family (or JSTD-008) CDMA system, transmission at 9.6 kbps (or 14.4 kbps) is called full-rate, 4.8 kbps (or 7.2 kbps), 2.4 kbps (or 3.6 kbps). The transmission rate at 1.2 kbps (or 1.8 kbps) is called half-rate, quarter-rate, and aeighth-rate, respectively. In each case, the rate of the modulation symbol is equal to 19.2 kbps. This is because symbol repetition is performed to fit the encoded data to 19.2 kbps.

In this case, in the forward link in the IS-95 family (or JSTD-008) CDMA system, all repeated symbols are transmitted, whereas in the reverse link, time is turned on / off. In full-rate, all symbols are transmitted, but in the case of half-rate, quarter-rate, and eighth-rate, 16 power control groups ( Only 8PCG, 4PCG, and 2PCG are transmitted to the Power Control Group (PCG).

The transmitted signal is received by the demodulator of the receiver and transmits the modulated symbol to the decoder of the receiver. The decoder performs blind detection to determine the data rate for the frame.

1 is a block diagram of a transmitting and receiving end of a general mobile communication system. Referring to FIG. 1, information input to the encoder 1 is input at a variable data rate, and the number of data input for each frame is different. For example, an IS-95 CDMA system transmits 172 bits per 20 ms frame at full rate, 80 bits per 20 ms frame at half rate, 40 bits per 20 ms frame at quarter rate, and finally 16 bits per 20 ms frame at ace rate. Such data is encoded by the encoder 1. The output of the encoder 1 is input to the iterator 2 and outputs immediately if the input data is at full rate, half-rate, quarter-rate, and aeighth-rate. Performs symbol repetition 1, 3, and 7 times, respectively. As a result, it has the same symbol rate as the full rate. The output of the repeater 2 is then input to an interleaver 3 and interleaved. The interleaved signal is then modulated in modulator 4 and then transmitted via antenna ANT1.

The signal transmitted as described above is input to the demodulator 5 through the antenna ANT2 of the receiver and demodulated. The symbols demodulated in the demodulator 5 and soft determined are input to the decoder 6 and decoded.

FIG. 2 is a block diagram illustrating an embodiment of the decoder shown in FIG. 1. Referring to FIG. 2, reference numeral 48 denotes a Viterbi decoder, which decodes an input symbol as a half-rate, quarter-rate, and aeighth-rate, respectively. The Viterbi decoders 50, 52, and 54 decode the input symbols as half-rate, quarter-rate, and aeighth-rate, respectively. Each symbol is re-encoded to obtain a symbol error rate (SER), and a cyclic redundancy check (CRC) and a yamamoto quality metric are used to determine the rate of the data. do.

The method for determining the data rate using the SER uses a method of comparing the input of the decoder and the input of the encoder by decoding the data and then re-encoding the data. In this case, when the encoder used is a convolutional encoder, a shift register may be used whenever an output is output from the Viterbi decoder to encode the data without delay.

In addition, when performing a variable rate without frame rate identification information, there is a method of implementing the decoder engine as many times as possible, or time division decoding with one decoder engine, all of which are blind for the variable rate. The disadvantage is that it performs detection.

However, in a communication system requiring a multimedia communication service requiring both voice and data services, a turbo encoder is used as an encoder. In the case of using such a turbo encoder, there is a turbo interleaver in the turbo encoder so that one frame must be fully decoded before encoding. Accordingly, there is a problem that a relatively large delay occurs in processing data in a high speed and multimedia communication system. In addition, the configuration of the encoder becomes complicated and the memory capacity becomes relatively large. Thus, there is a result that goes against the trend of light and small communication equipment.

To this end, the next generation of personal digital mobile communication systems based on CDMA technology uses a wider bandwidth than the existing IS-95 family (or JSTD-008) CDMA systems, and improves the data transmission speed to enable multimedia services. The trend is going. Thus, the number of channels allocated to a user can be variably operated according to the type of service.

For example, several channels may be simultaneously assigned to a single user, such as a channel transmitting high speed data such as an image, a channel transmitting high speed data, and a control message transmitting channel.

And, even when transmitting at high data rate, the variable data rate is supported similarly to the variable data rate of the existing IS-95 family. In addition, by providing flexibility to the number of data to be transmitted per frame using a flexible data rate technique, even when the number of data to be transmitted in a corresponding frame is small, the inefficiency of filling it with a random value can be improved. .

In order to solve the above-mentioned conventional problem of the present invention, in the case of using the turbo decoder, the variable data identification information for the next frame is inserted and transmitted using the remaining two bits of the entire bits for initializing the turbo decoder. The method and rate of variable rate indication of a high speed data channel in a mobile communication system by allowing the receiving end to decode the two bits to initialize the turbo decoder for the next frame to determine the rate of the high speed data channel for the next frame Its purpose is to provide a decision method.

Another purpose is to initialize the turbo decoder, but the variable rate indication method and the rate of the high-speed data channel in the mobile communication system to determine the variable data rate for the current frame using the remaining two bits and CRC bits of the total bits Its purpose is to provide a decision method.

1 is a block diagram of a transmitting and receiving end of a general mobile communication system.

FIG. 2 is a block diagram illustrating an embodiment of the decoder shown in FIG. 1. FIG.

3 is a flowchart illustrating a method of indicating a rate of a high speed data channel according to an embodiment of the present invention.

4 is a block diagram illustrating an apparatus for determining a rate of a high speed data channel according to an exemplary embodiment of the present invention.

Figure 5 (a) is a view showing the structure of a frame when using a convolutional encoder, (b) is a view showing the structure of a frame when using a turbo encoder applied to the present invention.

6 is a control flowchart illustrating a rate determination procedure of a high speed data channel according to another embodiment of the present invention.

7 is a control flowchart for explaining a detection procedure when not using the bits left in the general fast data channel rate determination procedure.

* Description of the symbols for the main parts of the drawings *

401: Receiver 402: A / D Converter

403: PN Correlator 404: Call Channel Correlator

405: Pilot Filter 406: Coherent Detector

407: Dubbo Decoder408: Microprocessor

In the present invention for achieving the above object a rate indicating method of a high-speed data channel in a mobile communication system,

Inserting frame capacity identification information for data transmission;

Inserting a frame rate indicator for the next frame into 2 bits of all the allocated bits to initialize the initial state of each frame and outputting to the turbo encoder;

Encoding according to a variable data rate in the turbo encoder, performing symbol repetition, performing inter-symbol puncturing, interleaving, and transmitting the interleaved modulation symbols;

Receiving, down-converting the transmitted signal, filtering the IF signal, and outputting a base digital signal;

Restoring data of a corresponding channel of the baseband digital signal and outputting the restored data to a turbo decoder;

Transferring the data decoded by the turbo decoder to a processor;

Extracting at least two frame rate indicators of the decoded data and then setting a register for next frame decoding.

According to another embodiment of the present invention, a method of determining a rate of a high speed data channel in a mobile communication system includes: inserting a frame capacity indicator for data transmission; Inserting identification information fixed to 2 bits of all the allocated bits to initialize the initial state of each frame and outputting to the turbo encoder; Encoding according to a variable data rate in the turbo encoder, performing symbol repetition, performing inter-symbol puncturing, interleaving, and transmitting the interleaved modulation symbols; Receiving, down-converting the transmitted signal, filtering the IF signal, and outputting a base digital signal; Restoring data of a corresponding channel of the baseband digital signal and outputting the restored data to a turbo decoder; Transferring the data decoded by the turbo decoder to a processor; Extracting at least two frame rate identification information of the decoded data, and then determining the rate by checking the fixed identification information and the CRC bit.

Hereinafter, with reference to the accompanying drawings as follows.

3 is a flowchart illustrating a method for indicating a rate of a high speed data channel according to an embodiment of the present invention, and FIG. 4 is a block diagram illustrating a rate determining apparatus for a high speed data channel according to an embodiment of the present invention. a) is a view showing the structure of a frame when using a convolutional encoder, (b) is a view showing the structure of a frame when using a turbo encoder applied to the present invention, Figure 6 according to another embodiment of the present invention A control flowchart for illustrating a rate detection procedure of a high speed data channel.

Referring to FIG. 3, a frame quality indicator is added to an input channel bit (301), and a variable rate indicator of the next bit is inserted into the remaining bit of the turbo encoder tail bit. (303), the encoder encodes (303), the symbol iterator performs the inter-symbol iteration and the puncturing iteration in symbol puncturing to make the same symbol as the maximum allocated data rate and output (S304, S305) The interleaver transmits 306 the modulated symbols.

4 is a block diagram of a receiver according to an embodiment of the present invention.

A receiver 401 for receiving a radio signal through an antenna, an analog / digital converter 402 for converting an output signal of the receiver 401 into a baseband digital signal, and an output signal of the analog / digital converter 402; The PN correlator 403 correlating the local PN codes provided by the local PN code generator (not shown) with each other and the call channel correlating the output signals of the PN correlator 403 with the Walsh code assigned to the corresponding channel. A pilot filter 405 for low band filtering the output signal of the correlator 404, the PN correlator 403, and a pilot filter 405 for phase shift and signal attenuation of the output signal of the call channel correlator 404. Coherent detector 406 and the output signal of the coherent detector 406 are respectively inputted and decoded, and the decoder 407 for inspecting the CRC included in the data and the test result of the decoder 407 And can decode the bits And a microprocessor 408 for determining the transmission rate of the data.

A rate indicating method and a rate determining method of a high speed data channel in a mobile communication system according to the present invention configured as described above will be described with reference to the accompanying drawings.

First, if the transmitter uses a turbo code for high-speed data transmission, a bit after the encoder is added to initialize each frame as shown in FIG. Here, the bit after the encoder uses 6 bits (T: 0 to 5 bits). Then, by using only 6 bits of all 8 bits, 2 bits remain, and the remaining bits (R) are inserted as variable rate identification information.

If a convolution code is used, that is, a Viterbi decoder is used, blind detection is already implemented for the variable rate applied to the existing low rate as shown in FIG. You can do the detection. In addition, the structure and frame structure of additional channels for high-speed data transmission in the IS-2000 standard add 8-bit zero bits (T: 0 to 7 bits) to initialize the initial state of each frame when using a convolution code. This exists.

FIG. 3 illustrates an additional channel structure of a transmitter when using a turbo code. A frame quality indicator is added to the channel bits (301), and in the case of the turbo encoder, a bit after the encoder is inserted. (302). At this time, the next frame rate indicator (①) is additionally inserted into the next bit.

The next frame identification information is 2 bits, and is transmitted as frame rate identification information for the next frame so that the receiver decoder can prepare in advance. For example, if the two bits are '00', the highest allocated data rate, if those two bits are '01', then the half rate of the highest allocated data rate, and if the '10' is the quota rate of the highest allocated data ready, Finally, if it is '11', it is used as the Ace rate of the maximum allocated data rate. Then, the receiving end also decodes the two bits and initializes the turbo decoder for the next frame.

When the trailing bit of the encoder is inserted, the turbo encoder encodes the encoded data (303), and repeats the encoded data in the symbol repeater and repeats the intersymbol puncturing in the symbol puncturing unit (304 and 305) to perform a variable rate. When transmitting at the maximum allocated data rate or at a different data rate than the maximum allocated data rate, the same symbol symbol rate is used as the modulation symbol rate of the maximum allocated data rate. Just do the puncturing.

The interleaved symbols are then interleaved in the block interleaver 306 and transmitted to the receiver as modulated symbols.

Here, the data rate for the channel to be initially set up among the message items initially sent in order to allocate the additional channel by transmitting variable rate identification information for the next frame in the remaining bits of 2 bits as described above. Include and send.

4 is a structure of a receiving end for the present invention. The received signal down converts the high frequency CDMA signal into an IF signal through the receiving unit 401, and filters the IF signal into a baseband digital signal through the A / D converter 402.

The PN correlator 403 then outputs an output signal obtained by correlating the local PN code generated from the local PN code generator with the base band signal to the call channel correlator 404 and the pilot channel 405.

In order to recover the data of the channel, the call channel correlator 404 outputs to the coherent detector 406 correlated with the Walsh code assigned to the channel, and the signal input to the pilot filter 405 is low filtered and coherent It is output to the detector 406.

The coherent detector 406 then removes the phase shift and attenuation of the signal caused by the channel environment using the pilot filter output and then passes it to the turbo decoder 407.

The turbo decoder 407 transmits the data decoded to the input signal to the processor 408, and the processor 408 extracts a 2-bit frame rate indicator among the decoded data to decode the next frame. Set each register of.

Each register setting for the variable data rate for the next frame is, for example, '00' at the highest allocated data rate, 01 at 1/2 the rate of the highest allocated data ready, and 10 at the highest allocated data ready. Since it is possible to determine in advance that it is used as the 1/4 rate of, the last 11 is the 1/8 rate of the maximum allocated data rate, the decoder can be initialized for the next frame.

As described above, an additional channel is allocated and transmitted to the receiving end, and the processing for the first frame is decoded through a data rate item of a message to which the base station (or terminal) allocates the additional channel.

Another embodiment of the present invention;

As shown in FIG. 3, when the turbo encoder is used, the remaining 2 bits are transmitted as '11' and the receiving end decodes the 2 bits, and then informs the upper level, and determines the rate using the 2 bits and the CRC bit. do. That is, after adding the frame quality indicator, the bit after the encoder is added (S301), and the bit 2 (2) is inserted into the 11 bit after the encoder (11) (S302), encoding (S303), symbol repetition, and popping. Chering and transmit to the modulation symbol (S304 ~ S306).

The transmitted modulation symbol is received by the receiver 401 shown in FIG. 4 and then the received signal is down-converted into a IF signal by converting a high frequency CDMA signal into an IF signal through the receiver 401, and then filtering the IF signal. The converter 402 makes a baseband digital signal. The PN correlator 403 outputs an output signal obtained by correlating the local PN code generated from the local PN code generator with the base band signal to the call channel correlator 404 and the pilot channel 405.

In order to recover the data of the channel, the call channel correlator 404 outputs to the coherent detector 406 correlated with the Walsh code assigned to the channel, and the signal input to the pilot filter 405 is low filtered and coherent It is output to the detector 406.

The coherent detector 406 then removes the phase shift and the attenuation of the signal caused by the channel environment using the pilot filter output and then passes it to the turbo decoder 407.

The turbo decoder 407 transmits the data decoded from the input signal to the processor 408, and the processor 408 extracts two bits of frame rate identification information from the decoded data and has the remaining two bits and the CRC bits. Determine the rate.

6 is a method of determining a rate at a receiving end of the present invention, and it is determined whether two or more good rates among physical CRCs (C1, C2, C4, and C8) for all data rates are determined (S610). More than one indicates the corresponding candidate set for each rate (full-rate, 1 / 2-rate, 1 / 4-rate, 1 / 8-rate) determination (S611).

However, if the physical CRC has one good rate rather than two or more (S620, S630, S640, S650), it is determined by determining whether each CRC is a good data rate in turn. That is, if C1 is a good rate (C1 = 1), it is determined to be full rate (S620, S621). If C2 is a good rate (C2 = 1), it is determined as half rate (S630, S631), and C3 is a good rate (C3). If = 1), it is determined as a quarter rate (S640, S641). If C4 is a good rate, it is determined as an ace rate (S650, S651), and the rate determination is finished.

Then, it is determined whether the CRCs are all bad (S660), and if all are bad, the rate is determined based on the left bits 'R'. That is, since the transmitted bit is transmitted with 11 left, the corresponding rate will be 11, and the remaining rate is less likely to be 11.

That is, when the CRCs are all bad (S660), R1, R2, R4, and R8 indicating reserved bits of each rate are reported as candidate sets (1XC, 2XC, 4XC, 8XC) for rate determination (S670). A rate at which R1, R2, R4, and R8 is 11 is used as the candidate set (S661 to S668).

Then, the higher level determines the retransmission to the candidate set through a logical transmission unit (LTU) CRC check.

Here, C1, C2, C4, and C8 representing the rate are CRC bits corresponding to full rate, half rate, quarter rate, and acetate rate, and 1X, 2X, 4X, 8X, 1XC, 2XC, 4XC, and 8XC are full rates. , Half-rate, quarter-rate, and ace rate.

7 shows a rate determination method for a method not using the remaining bits. First, when one or more of C1, C2, C4, and C8 is good, the rate is set as a candidate set in the same manner as described above (S701, S702), and when there is only one rate with a good physical CRC (S702 to S705). ) Is determined by the rate. If all CRCs are bad, all rates are set as candidates (S706).

In view of such a rate determination method, FIG. 7 can determine the rate in less time than the rate determination method of FIG. 6. That is, in the case of a high speed data channel (supplemental channel), at least one logical transmission unit (LTU) exists in each physical layer frame, and each logical transmission unit (LTU) has a CRC. When the rate is detected, the rate for the current frame can be determined using the result of the CRC present in each logical transmission unit (LTU) and the remaining two bits instead of the SER.

According to the rate indicating method and the rate determining method of the high speed data channel in the mobile communication system according to the present invention described above, the blind end detection is not performed at the receiving end by sending variable rate information for the next frame when the turbo encoder is used. It is possible to reduce the overhead due to detection can be prevented.

In addition, by inserting specific information into the remaining bits of the turbo encoder, the receiver can determine the rate using the specific information and the CRC bit, thereby making it possible to make the variable rate decision faster and easier.

Claims (5)

Inserting a frame capacity indicator for data transmission; Inserting frame rate identification information for the next frame into 2 bits of all allocated bits to initialize the initial state of each frame, and outputting them to the turbo encoder; Encoding according to a variable data rate in the turbo encoder, performing symbol repetition, performing inter-symbol puncturing, interleaving, and transmitting the interleaved modulation symbols; Receiving, down-converting the transmitted signal, filtering the IF signal, and outputting a base digital signal; Restoring data of a corresponding channel of the baseband digital signal and outputting the restored data to a turbo decoder; Transferring the data decoded by the turbo decoder to a processor; Extracting at least two frame rate identification information of the decoded data and then setting a register for next frame decoding. The mobile communication method of claim 1, wherein the decoding of the first frame received by the receiver includes a data rate of a channel to be initially set up among the message items initially sent to allocate an additional channel. Variable rate indication method of high speed data channel in system. The data rate of claim 1, wherein the remaining 2 bits are the maximum allocated data rate, 1/2 rate of maximum data rate, and 1/4 rate of maximum data rate by the combination of those 2 bits relative to the frame rate for the next frame. And a 1/8 rate identification information of the maximum data rate. Inserting a frame capacity indicator for data transmission; Inserting identification information fixed to 2 bits of all the allocated bits to initialize the initial state of each frame and outputting to the turbo encoder; Encoding according to a variable data rate in the turbo encoder, performing symbol repetition, performing inter-symbol puncturing, interleaving, and transmitting the interleaved modulation symbols; Receiving, down-converting the transmitted signal, filtering the IF signal, and outputting a base digital signal; Restoring data of a corresponding channel of the baseband digital signal and outputting the restored data to a turbo decoder; Transferring the data decoded by the turbo decoder to a processor; And extracting at least two frame rate identification information from the decoded data and checking the fixed identification information and the CRC bit to determine a rate. The method of claim 4, wherein the rate determination step is Determining, by the processor, whether the physical CRC for all data rates is better than two; If the determination result is more than one of the good rates, determining a good rate as a candidate rate; Determining that the data rate is determined by sequentially determining whether each CRC is a good data rate in a preset order when the physical CRC is a good one; If the determination result is one or more bad CRCs for all data rates, use the candidate set for determining the corresponding rate or all rates, and then check the CRC included in the logical transmission unit (LTU), Determining an error for a CRC included in the logical transmission unit (LTU) and determining retransmission.