KR0174617B1 - Data transmitter and receiver in direct spread / code division multiple access communication system - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

A direct spread / code division multiple access (DS / CDMA) communication system is disclosed.

2. The technical problem to be solved by the invention

The present invention implements a data transmitter and receiver to prevent data signal on / off or severe amplitude variation to facilitate data and clock recovery.

3. Summary of the Solution of the Invention

When the data transmitter of the present invention spreads information signals of multiple channels, the I-arm PN code is provided for the I-arm information signal of the first channel, and the Q-arm PN code is provided for the Q-arm information signal. And a spreading signal generating device for providing an inverted Q-arm PN code to the I-arm information signal of the channel and providing an I-arm PN code to the Q-arm information signal. The data receiver of the present invention multiplies an I arm PN code and a Q arm PN code by a digital I arm baseband spread signal and a Q arm baseband spread signal, respectively, and adds these multiplication results to generate an I arm despread signal. A despread signal generation device that multiplies the inverted I-arm PN code and the Q-arm PN code by the digital Q-arm baseband spread signal and the I-arm baseband spread signal, respectively, and adds these multiplication results to generate the Q-arm despread signal. It includes.

4. Important uses of the invention

Spread Spectrum Communication System.

Description

Data transmitter and receiver in direct spread / code division multiple access communication system

1 is a block diagram of a transmitter in a direct spread / code division multiple access communication system according to the prior art.

2 is a block diagram of a transmitter in a direct spread / code division multiple access communication system according to the present invention.

3 is a block diagram of a receiver of a direct spread / code division multiple access communication system according to the present invention.

4 is a diagram showing details of the configuration of the data demodulator of FIG.

5A and 5B illustrate signals processed in a transmitter of a direct spread / code division multiple access communication system according to the prior art and the present invention.

* Explanation of symbols for main parts of the drawings

101, 103 ~ 105, 322, 328: Quadrature code generator

102, 106-108, 111-118, 131-132, 137, 304-306, 313-317, 320, 321, 326, 327

109, 110, 311, 312: pseudo noise generator

119-126: finite length pulse response filter

127, 128, 133, 318, 319: adder

129, 130, 307, 308: Low pass filter

134, 303: band pass filter 135, 302: amplifier

136, 301: antenna

309, 310: Analog / Digital Converter

323 Initial sync and sync tracker

324: pseudo-noise clock controller

325: pseudo-noise clock generator

329: synchronous data demodulator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct spread / code division multiple access communication system. In particular, the present invention relates to data of a direct spread / sign division multiple access communication system that prevents signal on / off or severe amplitude variation and facilitates data and clock recovery. Relates to a transmitter and a receiver.

Spread Spectrum Communication refers to a method of communicating with a transmission bandwidth wider than that of a message signal to be transmitted.

The energy of the transmitted signal generally takes up more bandwidth than the bandwidth occupied by a binary coded digital signal consisting of zeros and ones, and demodulation is achieved by despreading the receiving signal with the same spreading signal as the spreading message signal. In a conventional communication system, when multiple users use the same transmission frequency band, interference occurs and communication cannot be performed. However, in spread spectrum communication, multiple users may use the same transmission frequency band by code division.

A spread spectrum communication system (hereinafter referred to as a CDMA communication system) that enables code division multiple access (Direct Division), frequency hopping (Frequency Hopping), As a CDMA communication system, a CDMA communication system (hereinafter, referred to as a DS / CDMA communication system) according to a direct diffusion method using a pilot channel is generally used as a CDMA communication system. have.

1 is a diagram illustrating a configuration of a transmitter of a DS / CDMA communication system according to the related art using a pilot channel.

Referring to FIG. 1, a signal to be transmitted includes pilot channel data PD and user channel data UD1 to UCN.

The pilot channel data PD is generally always transmitted with 1, which is used to establish pseudo noise (PN) synchronization in the receiver or as a reference synchronization signal when demodulating data. do. On the other hand, since the user channel data UD1 to UDN are information data to be actually transmitted, the receiver corresponding to the transmitter of FIG. 1 selects one channel among the N user channels and demodulates corresponding received data. The pilot channel data PD is multiplied by the output of the pilot channel orthogonal code generator 101 by the multiplier 102, and the user channel data UD1 to UDN are orthogonal code generators 103 to respective channels. The output of 105 is multiplied by multipliers 106-108. At this time, the pilot channel orthogonal code generator 101 and the user channel orthogonal code generators 103 to 105 generate different orthogonal codes, and the channels are distinguished from each other by the different orthogonal codes.

The outputs of the multipliers 102, 106-108 of each channel are divided into an I arm and a Q arm, and the multipliers 111-114 of the I arm have an output of the multipliers 102, 106-108 and an I arm PN code. The output IPN of the generator 109 is multiplied to output spread signals, and the Q-arm multipliers 115 to 118 output the outputs of the multipliers 102 and 106 to the output of the Q arm PN code generator 110. Each multiplier outputs spread signals. The outputs of the I-arm multipliers 111-114 and the outputs of the Q-arm multipliers 115-118 are finite impulse response (FIR) filters 119-122 and FIR filters, respectively. The output is filtered by 123 to 126. The outputs of the I-arm FIR filters 119-122 are added by the adder 127, and the outputs of the Q-arm FIR filters 123-126 are added by the adder 128, respectively, after the I-arm signal IS and I. Output as Q dark signal QS.

The IS and QS outputs of the I arm adder 127 and the Q arm adder 128 are respectively low pass filtered by a low pass filter (hereinafter referred to as LPF) 129 and 130 and then multiplier ( 131 and multiplier 132. The multiplier 131 multiplies the output of the LPF 129 by the in phase component cos (2πfct) of the carrier, and outputs the quadrature of the carrier and the quadrature of the output of the LPF 130. Multiplies the phase component sin (2πfct) and outputs it. The output of the I-arm multiplier 131 and the output of the Q-arm multiplier 132 are then added by the adder 133 and band-pass filtered by a band pass filter (hereinafter referred to as BPF) 134. After being amplified by an amplifier 135, it is propagated to the air through the antenna 136.

As described above, the DS / CDMA communication system uses a data transmitter / receiver of a spread spectrum communication system using Korean Patent Application No. 94-20801 entitled Pilot Channel, which was previously filed by the present applicant, and a multiplex using a Title Pilot Channel of 94-30497. It is a well-known technique as shown in the prior art in the data transceiver of the access spread spectrum communication system.

In the conventional DS / CDMA communication system, the input data of all channels is spread using the I-arm PN code IPN and the Q-arm PN code QPN and then transmitted. At this time, the I-arm multipliers 111-114 and the Q-arm multipliers 115-119 of all channels are multiplied by IPN and QPN, respectively, to spread input data of all channels. However, it should be noted that the output (I-arm channel data and Q-arm channel data) of the adder 127 and the adder 128 may become zero simultaneously depending on the input data and the IPN and QPN. When the outputs of the adder 127 and the adder 128 become zero at the same time, the outputs of the multiplier 131 and the multiplier 132 become zero at the same time, and finally the output of the adder 133 propagated through the antenna 136 It becomes zero.

In FIG. 5A, reference numerals T1 to T8 denote sections in which the output of the adder 127 and the output of the adder 128 become zero at the same time. If such a section is repeatedly present, the system takes on / off keying modulation according to the data pattern and the PN code pattern. When the on / off keying modulation occurs in the transmitter as described above, the receiver recognizes the on / off keying modulation as if the signal is on / off. Then, the receiver will perform the data and clock recovery operation even in such an abnormal situation, and as a result, there is a problem that it is difficult to restore the normal data and clock.

Meanwhile, the problem that the outputs of the adders 127 and 128 become zero at the same time may be solved by appropriately adjusting the gain of each channel, but the output of the adders 127 and 128 will have a very low amplitude. When such low amplitude output is present, there is a substantial variation in amplitude between the output due to data transmission and as a result, the system suffers from Amplitude Shift Keying. In order to prevent such amplitude shift keying, there is a burden of using a high-performance amplifier having excellent linearity as the AMP 135 which is a power amplifier connected between the BPF 134 and the antenna 136.

Accordingly, an object of the present invention is to provide a data transmitter and a receiver for preventing the I-arm channel data and the Q-arm channel data from being simultaneously zero in a DS / CDMA communication system.

Another object of the present invention is to provide a data transmitter and receiver for preventing a signal from being turned on / off in a DS / CDMA communication system.

Another object of the present invention is to provide a data transmitter and a receiver for facilitating data and clock recovery in a DS / CDMA communication system.

It is still another object of the present invention to provide a data transmitter and a receiver for preventing severe amplitude variation of a transmission signal in a DS / CDMA communication system.

It is still another object of the present invention to provide a data transmitter and a receiver which eliminates the burden of using a power amplifier having excellent linearity in a DS / CDMA communication system.

It is still another object of the present invention to provide a spreading signal generating device and a despreading signal generating device for preventing a signal on / off phenomenon or a severe amplitude change in a DS / CDMA communication system and easily recovering a data and a clock.

In the data transmitter of the present invention for achieving the above objects, the I-arm PN code is provided for the I-arm information signal of the first channel when the information signal of multiple channels is spread, and the Q-arm PN code is provided for the Q-arm information signal. And a spreading signal generating device for providing an inverted Q-arm PN code to the I-arm information signal of the channel for the next set number and providing an I-arm PN code to the Q-arm information signal.

The data receiver of the present invention multiplies the I-arm baseband spreading signal and the Q-arm baseband spreading signal by the I-arm PN code and the Q-arm PN code, respectively, and add these multiplication results to generate the I-arm spread signal. A despread signal generation device that multiplies the inverted I-arm PN code and the Q-arm PN code by the digital Q-arm baseband spread signal and the I-arm baseband spread signal, respectively, and adds these multiplication results to generate the Q-arm despread signal. It includes.

According to the present invention, there is provided a spreading signal generating apparatus of a DS / CDMA communication system for transmitting information signals through a plurality of channels; A plurality of channels; a first PN code generator for generating an I-arm PN code, a second PN code generator for generating a Q-arm PN code, an inverter for inverting the Q-arm PN code and outputting an inverted Q-arm PN code; A first multiplier that multiplies the information signal of the first channel by the I-arm PN code, a second multiplier that multiplies the information signal of the first channel by the Q-arm PN code, and the first of the plurality of channels A first group multiplier for multiplying the information signals of the remaining channels other than the channel with the inverted Q-arm PN code, a second group multiplier for multiplying the information signal of the remaining channel and the I-arm PN code, respectively; A first adder that adds a multiplication result of the first multiplier and the first group multiplier and outputs the addition result as an I-arm spread signal, and adds a multiplication result of the second multiplier and the second group multiplier and adds the result of the addition; As a Q-arm spread signal A second adder for output comprises at least. The information signal of the first channel is a pilot channel signal, and the information signal of the remaining channels is preferably implemented as two user channel signals.

An apparatus for generating inverse converted signals in a DS / CDMA communication system according to the present invention includes a first PN code generator for generating an I-arm PN code, a second PN code generator for generating a Q-arm PN code, and inverting the I-arm PN code. An inverter for outputting the inverted I-arm PN code, a first multiplier for multiplying the digital I-arm baseband spread signal with the I-arm PN code, and a digital Q-arm baseband spread signal and the inverted I-arm pseudo A second multiplier for multiplying a noise code, a third multiplier for multiplying the Q-arm baseband spread signal and the inverted I-arm pseudo noise code, and a multiplier of the I-arm baseband spread signal and the Q-arm PN code A multiplier by adding a fourth multiplier, a multiplication result by the first multiplier and a multiplication result by the third multiplier, and outputting the addition result as an I-arm despread signal; and a multiplication result by the second multiplier And multiplication result by the fourth multiplier And comprises a second adder for outputting the addition result as a Q cancer despreading signal at least.

According to the present invention, since the I-arm spread signal and the Q-arm spread signal do not become zero at the same time, it is possible to solve the on / off phenomenon and the severe amplitude variation of the information signal. In addition, the receiver can easily recover the data and clock, thereby improving the performance of the receiver, and eliminates the burden of having a linear power amplifier with excellent linearity.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In addition, in the following description, many specific details such as components of specific circuits are shown, which are provided to help a more general understanding of the present invention, and the present invention may be practiced without these specific details. It will be obvious to those skilled in the art. In the following description of the present invention, if it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. The terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or a chip designer, and the definition should be based on the contents throughout the specification.

2 is a view showing the structure of a transmitter of the DS / CDMA system proposed in the present invention.

The signals to be transmitted in FIG. 2 are mainly pilot channel data PD and user channel data UDI, UD2, ..., UDN. The pilot channel data PD is always transmitted with 1, which is used to establish PN synchronization at the receiver or to perform PN synchronization tracking, or as a reference synchronization signal for data demodulation at the receiver. In contrast, the user channel (traffic) data UD1, UD2, ..., UDN are information data to be actually transmitted. At this time, the number of user channels is shown as N, which may be appropriately set according to the system specification. In addition, the receiver corresponding to the transmitter illustrated in FIG. 2 selects one of the N user channels allocated to receive and demodulate data. The pilot channel data PD is multiplied by the output of the orthogonal code generator 101 by the multiplier 102, and the user channel data UD1, UD2, ..., and UDN are respectively orthogonal code generators 103, 104, ... 105 is multiplied by the multipliers 106, 107, ..., 108 and output. The signal output from the multiplier 102 is a signal in which the pilot channel data PD is orthogonally coded, and the signal output from the multipliers 106, 107, ..., 108 is orthogonal to the user channel data UD1, UD2, ..., UDN. Coded signal. At this time, the orthogonal code generators 101, 103, 104, ..., 105 of each channel generate different orthogonal codes that are orthogonal to each other. A Walsh code may be used as the orthogonal code. Therefore, each channel is distinguished and separated by different orthogonal codes. The orthogonal coded signals output from the multipliers 102, 106, 107, ..., 108 of each channel are provided to the multipliers 111, 112, 113, 114, 115, 116, 117, ..., 118 which are divided into I arm and Q arm and connected to the rear end. .

The operation of the present invention as described above is also performed in the DS / CDMA communication system according to the prior art. However, the present invention is characterized in that each of the orthogonally coded channel data is generated as a spread signal by the PN coded IPN and QPN.

The output of the pilot channel multiplier 102 is multiplied by the multiplier 111 and the IPN which is the output of the I arm PN code generator 109 in the I arm, and is output by the Q arm PN code generator 110 in the Q arm. QPN and multiplier 115 multiply and spread. However, PN spreading of the user channel signal is performed differently from the pilot channel signal. In order to spread the output of the user channel multipliers 106, 107, ..., 108, the QPN generated by the Q-arm PN code generator 110 and then multiplied by -1 by the multiplier 137 (inverted QPN). In the Q arm, the IPN generated from the I arm PN code generator 109 is used. That is, the first group multipliers 112, 113, ..., 114 of the I arm multiply the inverted QPNs by the outputs of the multipliers 106, 107, ..., 108, respectively, and output the spread channel data. The two groups of multipliers 116, 117, ..., 118 multiply the output of the multipliers 106, 107, ..., 108 by IPN, respectively, and output the spread channel data. Thus, in the present invention, unlike the prior art, IPN is multiplied by user group data of the Q arm by the second group multipliers 116, 117, ..., 118, and the first group multipliers 112, 113, ..., 114 Inverted QPN is multiplied by user channel data of I arm.

Thus, in the present invention, in spreading the information signal of each channel, the method of spreading the information signal of the first channel (pilot channel data PD) and the information signal of the next channel adjacent to the first channel (user channel data). There is a difference in the way of spreading UD1, UD2). In contrast, in the prior art, when an information signal of all channels is spread, an I arm PN code is provided to the I arm, and a Q arm PN code is provided to the Q arm. In the present invention, however, when the pilot channel data PD, which is the information signal of the first channel, is spread, the I-arm PN code is provided to the I-arm and the Q-arm PN code is provided to the Q-arm as in the conventional art. . In the case of spreading user channel data UD1 and UD2 which are information signals of the next channel, the I-arm PN code and the Q-arm PN code are provided alternately. In other words, the I-arm is provided with an inverted Q-arm PN code, and the Q-arm is provided with an I-arm PN code.

Meanwhile, in FIG. 2, channels provided by crossing the I-arm PN code and the Q-arm PN code are user channels # 1 and # 2, which are second and third channels. In addition, the I-channel PN code and the Q-arm PN code are alternately provided to the user channel #N, which is the last channel. However, it should be noted that when the number N of user channels is small, it is desirable to provide an I-arm PN code and a Q-arm PN code at the time of spreading all user channel data. However, when the number of user channels increases, When spreading all user channel data, it is not desirable to provide the I-arm PN code and the Q-arm PN code equally intersected. In other words, the I-arm PN code and the Q-arm PN code are provided alternately for the number of user channels set when spreading a plurality of user channel data, and the I-arm PN code and Q for other fixed number of user channels. It is desirable for the dark PN code to be provided directly without crossing.

For example, in FIG. 2, when the number N of user channels is 5, PN codes are directly provided for the pilot channel, and PN codes are alternately provided for the user channels # 1 and # 2. PN codes may be directly provided for the user channel # 3, and PN codes may be alternately provided for the user channels # 4 and # 5. That is, in the DS / CDMA system supporting a plurality of information signal channels, when spreading a plurality of information signals according to the present invention, PN codes are directly provided for the information signal of the initial channel, and information up to the next fixed number of channels is provided. For the signal, PN codes are provided alternately. As described above, according to the spreading method of the present invention, in a DS / CDMA system supporting a plurality of information signal channels, the PN code may be provided in a repetitive structure such as direct → cross → direct → cross →.

Referring back to FIG. 2, the outputs of the I arm multipliers 111, 112, 113, ..., 114 and the outputs of the Q arm multipliers 115, 116, 117, ..., 118 are the I arm FIR filters 119, 120, 121, ... 122) and Q-arm FIR filters 123, 124, 125, ..., 126. The outputs of the I arm FIR filters 119, 120, 121, ..., 122 are added by the adder 127 to form the I arm spread signal IS, and the Q arm FIR filters 123, 124, 125, ... The output is added by the adder 128 to form the Q arm spread signal QS. The I-arm spread signal IS and the Q-arm spread signal QS output from the adder 127 and the adder 128 are lowpass filtered by the LPF 129 and the LPF 130, respectively, and then the multiplier 131 and the multiplier 132. Are entered respectively. The I arm multiplier 131 multiplies the formed I arm spread signal IS by the in-phase component cos (2πfct) of the carrier to output an I arm modulated signal, and the Q arm multiplier 132 generates the Q arm spread signal QS and the carrier wave. The Q-arm modulated signal is output by multiplying the quadrature phase component sin (2πfct) by. The I arm modulated signal and the Q arm modulated signal output from the multiplier 131 and the multiplier 132 are added by the adder 133 and band-pass filtered by the BPF 134. The signal bandpass filtered by the BPF 134 is power amplified by the AMP 135, which is a power amplifier, and then propagated to the air through the antenna 136 as a high frequency signal.

As described above, the transmitter of the DS / CDMA communication system according to the related art shows that there was a section in which the outputs of the adders 127 and 128 became zero at the same time according to the channel data and the pattern of the PN code IPN and QPN. Could.

However, in the transmitter of the DS / CDMA communication system according to the present invention configured as shown in FIG. 2, even when the same PN code IPN and QPN occur as shown in FIG. 5A, the outputs of the adders 127 and 128 become zero at the same time. This absence can be seen from FIG. 5b. Since the outputs of the adders 127 and 128 do not become zero at the same time, this addition result does not become zero even when the carrier modulated I-arm spread signal IS and the Q-arm spread signal QS are added to the adder 133. Accordingly, the phenomenon that the transmitter is on / off keying modulation does not occur, and there is no burden of using an amplifier having excellent linearity as the AMP 135. In addition, since the on / off modulation of the transmitter does not occur, the receiver can more easily recover data and clock and establish a PN synchronization. As a result, the performance is improved.

3 is a diagram illustrating a structure of a receiver of a DS / CDMA communication system proposed in the present invention. The structure of this receiver is designed to correspond to the transmitter shown in FIG. More specifically, in the transmitter according to the present invention, an inverted Q-arm PN code is provided as an I arm when generating a spread signal, and an I-arm PN code is provided as a Q arm. Doing. Correspondingly, in the receiver according to the present invention, when the despreading operation is performed, the I-arm PN code and the Q-arm PN code are provided as the I-arm, and the inverted I-arm PN code and the Q-arm PN code are used as the Q-arm. To be provided.

Referring to FIG. 3, the high frequency signal received by the antenna 3 is low noise amplified by a low noise amplifier 302, band-pass filtered by the BPF 303, and then multiplied by the multiplier 304. It is multiplied by the receiving local oscillation frequency cos (2πf _RF t). At this time, the signal output from the multiplier 304 is an intermediate frequency signal.

The output of the multiplier 304 is divided into I arm and Q arm, and in I arm, the in-phase component cos (2πf _IF t) of the intermediate frequency is multiplied by the multiplier 305, and in the Q arm, the quadrature phase component sin (2πf) of the intermediate frequency. _IF t) is multiplied by multiplier 306. The signals output from the multipliers 305 and 306 are analog I-arm and Q-arm baseband spread signals from which carrier components are removed, respectively. The outputs of the multipliers 305 and 306 are low pass filtered by LPF 307 and 308, respectively, and the I-arm and Q-arm digital by analog / digital converters 309 and 310. It is converted into a spread signal. The outputs of the I-arm A / D converter 309 and the Q-arm A / D converter 310 are digital baseband spread signals, which are despread by the PN code as described below.

The I-arm digital baseband spread signal, which is the output of the I-arm A / D converter 309, is multiplied by the multiplier 314 and the IPN, which is the output of the I-arm PN code generator 311, in the I-arm, and Q-arm in the Q-arm. The multiplier 317 multiplies QPN, which is the output of the PN code generator 312. The Q-arm digital baseband spread signal, which is the output of the Q-arm A / D converter 310, is multiplied by the output of the multiplier 313 which multiplies the IPN by -1 to the IPN and outputs the inverted IPN. In the Q arm, the multiplication is performed by the QPN and the multiplier 316. In order to obtain the I-arm despread signal from which the PN component has been removed, the output of the multiplier 314 and the output of the multiplier 316 may be added by the adder 318, and the multiplier 315 may be used to obtain the Q-arm despread signal. The output and the output of the multiplier 317 may be added by the adder 319. At this time, the signal output from the adder 318 is the I-arm despread signal IAS from which the PN code component has been removed, and the signal output from the adder 319 is the Q-arm despread signal QAS from which the PN code component has been removed. The I-arm and Q-arm despread signals IAS and QAS are despread signals with the PN signal components removed, but the quadrature code components remain. The operation of removing the orthogonal code component is performed as follows.

The pilot channel orthogonal code generator 322, the multiplier 320 and the multiplier 321 removes the orthogonal code component of the pilot channel. In other words, the multiplier 320 multiplies the I-arm despread signal IAS and the orthogonal code generated by the pilot channel orthogonal code generator 322 to output the I-arm pilot signal IPS. The multiplier 321 multiplies the Q-arm despread signal QAS by the orthogonal code generated by the pilot channel orthogonal code generator 322 to output the Q-arm pilot signal QPS. The pilot channel orthogonal code generator 322 generates an orthogonal code identical to the orthogonal code generated by the pilot channel orthogonal code generator 101 of FIG.

The I-arm pilot signal IPS and the Q-arm pilot signal QPS are signals obtained by removing the PN code component and the orthogonal code component and are input to the initial synchronization and synchronization tracking unit 323 and used to establish the PN synchronization. The result processed by the initial synchronization and synchronization tracking unit 323 is input to the PN clock controller 324, the PN clock controller 324 receives the results from the PN initial synchronization and synchronization tracking unit 323 to PN The operation of the clock generator 325 is controlled. The PN clock generator 325 generates a control signal PNC for matching the phase between the transmission and reception PN codes. The I-arm PN code generator 311 and the Q-arm PN code generator 312 are set according to the generated control signal PNC. PN code is generated at the same speed.

By the initial synchronization and synchronization tracking unit 323, PN clock controller 324, PN clock generator 325, I-arm PN code generator 311 and Q-arm PN code generator 312 as described above The phases of the transmitting PN code and the receiving PN code coincide. These operations are PN Acquisition and PN Tracking, which play a very important role in the spread spectrum communication system. Once the PN synchronization tracking process is performed after the PN initialization is established, the operation of demodulating the actually transmitted information data is performed.

In order to demodulate the data of the user channel, for example, the data of the Nth user channel, from the I-arm despread signal IAS and the Q-arm despread signal QAS from which the PN signal component is removed, the orthogonal code component must be removed first. The user channel orthogonal code generator 328 generates an orthogonal code of the N-th channel, and the I-arm despread signal IAS and the Q-arm despread signal, respectively, in the multiplier 326 and the multiplier 327, respectively. When multiplied by the QAS, only the user information signal of the N-th channel having the orthogonal coded component is removed. The I-arm user information signal ICS and the Q-arm user information signal QCS of the Nth channel are input to the synchronous data demodulator 329. The synchronous data demodulator 329 restores the information data by using the I arm pilot signal IPS and the user information signal ICS, and the Q arm signal pilot signal QPS and the user information signal QCS.

4 is a diagram showing in detail the configuration of the synchronous data demodulator 329 shown in FIG.

The I arm pilot signal IPS and the Q arm pilot signal QPS are cumulatively added by accumulators 401 and 402, respectively, and the I arm user information signal ICS and Q arm user information signal QCS are accumulators 403, respectively. 404 is cumulatively added. The signals of the pilot channel and the user channel cumulatively added by the accumulators 401 to 404 are dumped by the dumpers 405 to 408 at a time point t = T, which is a symbol duration. At this time, the dump period of the dumper 407 and 408 of the user channel for optimizing the performance of the system should be the same as the symbol duration t = T, and the dumper 405 and 406 of the pilot channel are always t = T. It is not necessary and sufficient if t≥T.

The output of the Q arm dumper 406 of the pilot channel and the output of the I arm dumper 407 of the user channel are multiplied by the multiplier 409, and the output of the one arm dumper 405 of the pilot channel and the user channel. The output of the Q arm dumper 408 is multiplied by the multiplier 410. The outputs of the multiplier 409 and the multiplier 410 are subtracted by the subtractor 411 to obtain the difference. The subtractor 411 calculates a phase difference between the pilot channel and the user channel. The data determiner 412 restores the data by using the difference and outputs the restored data RD. The data decision unit 412 restores data by hard decision or soft decision of the output from the subtractor 411. According to the hard decision method, the data determination unit 412 restores the data to '0' if the output of the subtractor 411 is greater than or equal to 0, and restores the data to 1 if the output of the subtractor 411 is less than zero. . In contrast, according to the soft determination method, the data determination unit 412 is implemented by a Viterbi Decoder or the like to restore data.

As described above, the present invention proposes a cross-control scheme for providing an inverted Q-arm PN code for I arm and an I-arm PN code for Q arm when generating a spread signal. Accordingly, since the I-arm spread signal and the Q-arm spread signal do not become zero at the same time, there is an advantage of resolving the severe amplitude fluctuation on the on / off phenomenon of the information signal. In addition, the receiver can easily recover the data and the clock, resulting in an improvement in the performance of the receiver, and has the advantage of relieving the burden of having a linear power amplifier with excellent linearity.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. For example, in a specific embodiment of the present invention, when the first channel among the plurality of channels is a pilot channel and the remaining channels are user channels, the first channel data is spread so that PN codes are directly supplied. In the case of spreading data of several channels, PN codes are exchanged and supplied. However, the present invention can be equally applied even when the first channel is a user channel.

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.

Claims (19)

A transmitter in a direct spread / code division multiple access communication system, comprising: a pilot channel encoder for outputting encoded pilot channel data by multiplying pilot channel data by a predetermined pilot channel orthogonal code; A user channel encoder for outputting a plurality of user channel data encoded by multiplying orthogonal codes for a plurality of user channels in which a plurality of user channel data and adjacent codes are orthogonal to each other, and eye (I) female pseudo noise ( A first noise code generator for generating a PN) code; A second pseudo-noise code generator for generating a Q (Q) female pseudo-noise code; A pilot channel for multiplying the coded pilot channel data by the eye cancer pseudo noise code to output spread eye cancer pilot channel data, and a multiplier of the cu arm pseudo noise code to output spread cu arm pilot channel data. A diffuser for the solvent; Outputs a plurality of spread IAM user channel data by multiplying the inverted cue pseudo noise code by the encoded plurality of user channel data, and outputs a plurality of spread CUAM user channel data by multiplying the I AM pseudo noise code A user channel diffuser; A first adder configured to add the spread eye arm pilot channel data and the spread eye arm user channel data to output eye spread data; A second adder configured to output the cue spread data by adding the spread cue pilot channel data and the spread cue user channel data; A first modulator for outputting an eye arm modulated signal by multiplying the eye arm spread data by an in-phase component of a predetermined carrier; A second modulator for multiplying the quadrature phase component of the carrier by the cue spread data to output a cue modulated signal; A third adder for adding and outputting the eye arm modulated signal and the cu arm modulated signal; A bandpass filter for bandpass filtering the output of the third adder; An amplifier for amplifying the output of the band pass filter and outputting it as a high frequency signal; Transmitter comprising at least an antenna for propagating the high frequency signal to the air. The transmitter of claim 1, further comprising an inverter that multiplies the cue pseudo noise code by a value of -1 and provides the multiplication result as an inverted cue pseudo noise code to the spreader for the user channel. A receiver in a direct spread / code division multiple access communication system, comprising: a low noise amplifier for low noise amplifying a high frequency signal received through an antenna; A bandpass filter for bandpass filtering the output of the low noise amplifier; A first multiplier for multiplying a reception local oscillation frequency by an output of the band pass filter to output an intermediate frequency signal; A second to output an analog eye (I) baseband spreading signal and a cue (Q) arm baseband spreading signal from which the carrier component is removed by multiplying the intermediate frequency signal by the in-phase component and the quadrature-phase component of each carrier; A multiplier and a third multiplier; A first converter and a second converter for converting the analog eye arm baseband spreading signal and the analog cue baseband spreading signal into a digital eye arm baseband spreading signal and a cuam baseband spreading signal respectively; A first pseudo noise code generator and a second pseudo noise code generator for generating an eye cancer pseudo noise (PN) code and a cu cancer pseudo noise code, respectively; Multiply the IAM pseudo-noise code by the digital I-Am baseband spread signal, multiply the Q-AQ base noise spread signal by the Q-A-MQ base noise spread signal, and use these two multiplication results A first despreader that outputs a; Multiply the i-am pseudo-noise code inverted by the digital cu-am baseband spread signal, multiply the cu-am pseudo-noise code by the digital i-am spread signal, and then use the two multiplication results to generate a cu-am despread signal. A second despreader for outputting; A first decoder and a second decoder for multiplying each of the eye arm despread signal and the cu arm despread signal by a predetermined pilot channel orthogonal code and output a decoded eye arm pilot signal and a cu arm pilot signal, respectively; A third decoder and a fourth decoder configured to multiply each of the eye arm despread signal and the cu arm despread signal by a predetermined user channel orthogonal code and output a decoded eye arm user information signal and a cu arm user information signal, respectively; Synchronization of the pseudo noise code generated by the first and second pseudo noise code generators is included in the high frequency signal by using the synchronization state of the pseudo noise code included in the eye arm pilot signal and the long cue pilot signal. A synchronization controller for continuously matching the synchronization of the pseudo-noise code and outputting a result signal corresponding thereto as a control signal for controlling the speed of generating the pseudo-noise code of the first and second pseudo-noise code generators; And an information data demodulator for demodulating the eye and cue user information signals into information data using the eye and cue pilot signals. 4. The apparatus of claim 3, wherein the information data demodulator; A first accumulator and a dumper that accumulate the eye arm pilot signal and dump and output it for every symbol duration; a second accumulator and dumper that accumulate and output the cue pilot signal and dump and output each symbol duration; A third accumulator and dumper for accumulating user information signals and dumping them for each symbol duration and outputting them; a fourth accumulator and dumper for accumulating and outputting cue user information signals and dumping and outputting each symbol duration; and a second accumulator and dumper. An eighth multiplier multiplying the output of the third accumulator and the output of the dumper, a ninth multiplier multiplying the outputs of the first accumulator and the dumper and the outputs of the fourth accumulator and the dumper, and the eighth multiplier A subtractor for subtracting the multiplication result by the ninth multiplier from the multiplication result and outputting the result; And a data decision unit for soft decision to output the result of the decision as reconstruction data. 5. The receiver as claimed in claim 4, wherein the data determination unit determines the information data at 0 level when the output of the subtractor is 0 level or more and 1 level when the output of the subtractor is less than 0 level. 3. The apparatus of claim 2, wherein the user channel diffuser; A first group multiplier that multiplies the inverted cue pseudo noise code by each of the encoded plurality of user channel data, and a second group multiplier that multiplies the eye cancer pseudo noise code by each of the encoded plurality of user channel data. Characterized in that the transmitter. 7. The apparatus of claim 6, wherein the pilot channel diffuser; A multiplier for multiplying the coded pilot channel data by the eye arm pseudo noise code and outputting the spread eye arm pilot channel data, and multiplying the coded pilot channel data by the cue pseudo noise code And a second multiplier for outputting the spread cue pilot channel data. 8. The apparatus of claim 7, wherein the multipliers of the first multiplier and the first group multiplier are connected between the multiplier and the first adder, and between the multipliers of the second multiplier and the second group multiplier and the second adder. And a plurality of finite length impulse response filters for filtering the spread eye arm pilot channel data and the cu arm pilot channel data and the spread eye arm user channel data and the cu arm user channel data for each channel. The transmitter further comprises. 8. The apparatus of claim 7, further comprising: a first low pass filter connected between the first adder and the first modulator to low pass filter the eye arm diffusion data to output the low pass filtering result to the first modulator; And a second low pass filter connected between the second adder and the second modulator to low pass filter the cue spread data to output the low pass filtering result to the second modulator. transmitter. 4. The apparatus of claim 3, further comprising an inverter that multiplies the eye arm pseudo noise code with a value of -1 and provides the multiplication result to the second despreader as the inverse eye arm noise signal. Receiver. 4. The apparatus of claim 3, further comprising first and second low pass filters connected between the second multiplier and the first converter and between the third multiplier and the second converter. The low pass filter low-pass filters the analog eye cancer baseband spreading signal to the first converter, and the second low pass filter low-pass filters the analogue cue baseband spreading signal to the second converter. Receiver characterized in that the output. 11. The apparatus of claim 10, wherein the first despreader; A fourth multiplier for multiplying the digital I am baseband spreading signal by the eye arm pseudo noise code, a fifth multiplier for multiplying the digital cue baseband spreading signal by the cue pseudo noise signal, and the fourth multiplier And a first adder which adds a multiplication result by the fifth multiplier and outputs the addition result as the eye arm despread signal. 13. The apparatus of claim 12, wherein the second inverse spreader comprises: a sixth multiplier that multiplies the inverted eye cancer pseudo noise code by the digital cue baseband spread signal, and the cue pseudo pseudo signal on the digital eye cancer spread signal. And a seventh multiplier that multiplies a noise code, and a second adder that adds a multiplication result by the sixth multiplier and the seventh multiplier and outputs the addition result as the cu-arm despread signal. A spreading signal generating apparatus of a direct spread / code division multiple access communication system for transmitting an information signal through dozens of channels, comprising: a first pseudo noise (PN) code generator for generating an eye (I) female pseudo noise (PN) code; A second pseudonoise code generator for generating a cue (Q) female pseudo noise code, a reversal device for outputting an inverted cue pseudo noise code by inverting the cue pseudo noise code, and a first one of the plurality of channels A first multiplier for multiplying an information signal and the eye cancer pseudo noise code, a second multiplier for multiplying the information signal of the first channel and the cue pseudo noise code, and the rest of the plurality of channels other than the first channel A first group multiplier for multiplying the information signal of the filter and the inverted cu-am pseudo noise code, and a second group multiplier for multiplying the information signal of the remaining channels and the eye cancer pseudo noise code, respectively; A first adder that adds a multiplication result of the first multiplier and the first group multiplier and outputs the addition result as an eye arm spread signal, and adds a multiplication result of the second multiplier and the second group multiplier, And a second adder for outputting the addition result as a cu-amm spread signal. 15. The apparatus of claim 14, wherein the information signal of the first channel is a pilot channel signal. 15. The apparatus of claim 14, wherein the information signal of the remaining channels is a user channel signal. 17. The apparatus of claim 16, wherein the remaining channels are two. 15. The method of claim 14, wherein each of the multipliers of the first multiplier, the second multiplier, the first group multiplier, and the multiplier of the second group multiplier and the first adder and the second adder is a finite field impulse response. And a filter is further included to output the multiplication result by each multiplier to the first adder and the second adder. In a direct spread / code division multiple access communication system and a spreading signal generating apparatus, a first noise code generator for generating an eye (I) female pseudo noise (PN) code and a queue (Q) female pseudo noise code are generated. A second pseudo-noise code generator, an inverter for inverting the eye-arm pseudo-noise code and outputting an inverted eye-arm pseudo-noise code, and a multiplier for multiplying a digital eye-arm baseband spread signal and the eye-arm pseudo-noise code A first multiplier, a second multiplier for multiplying the digital Q-arm baseband spread signal and the inverted eye arm pseudo noise code, and a third multiplier for multiplying the Q-arm baseband spread signal and the inverted eye arm pseudo noise code; A fourth multiplier multiplying the i-arm baseband spread signal by the cue pseudo noise code, a multiplication result by the first multiplier, and a multiplication result by the third multiplier; A first adder for outputting an i-arm despread signal and a second adder for adding the multiplication result by the second multiplier and the multiplication result by the fourth multiplier and outputting the addition result as a cu-arm despread signal; De-spread signal generating device comprising a.