KR100346218B1 - Channel spreading device and method for cdma communication system - Google Patents

Abstract

A channel spreader of a base station of a code division multiple access communication system includes a spreading code generator for generating a spreading code of a real component and a spreading code of an imaginary component corresponding to a specified channel spreading code index, and inputting a mode control signal. And a complex multiplier for inputting a channel signal and complex multiplying the input channel signal and the spreading codes by a channel input when the mode control signal is a BPSK modulation mode. .

Description

CHANNEL SPREADING DEVICE AND METHOD FOR CDMA COMMUNICATION SYSTEM}

The present invention relates to a spreading device and a method for a code division multiple access communication system, and more particularly, to an apparatus and a method for spreading a channel in a complex spreading method.

In general, Code Division Multiple Access (hereinafter referred to as CDMA) communication system is a method for increasing capacity, and uses a method of channel separation using orthogonal code. Doing. An example of performing channel division by the orthogonal code as described above is the forward link of IS-95 / IS-95A, and it is applied by time alignment in the reverse link. can do.

However, the IMT 2000 system, which is the next generation CDMA communication system, and the IS-95 system, which is a conventional CDMA communication system, use different modulation and demodulation methods to orthogonally spread and despread signals, thereby causing compatibility problems between the two systems. The IMT systems can serve different rates. (1X: bandwidth used by IS-95 systems today, 3X: three times the bandwidth used by IS-95 systems, 6X: six times the bandwidth used by IS-95 systems, 9X: used by IS-95 systems 9 times the bandwidth, 12X: 12 times the bandwidth used in the IS-95 system, the base station and the terminals of the 3X or more IMT-2000 system using the QPSK modulation and demodulation method generates an orthogonal spreading and despreading signal The base station and the terminal of the IS-95 system (including the 1X system of the IMT-2000 system) generate orthogonal spreading and despreading signals using BPSK modulation and demodulation. Hereinafter, the orthogonal code is assumed to be a Walsh code.

Let's look at this formally. If the base station transmitter transmits QPSK orthogonal spreading of the input signals dI and dQ using an orthogonal spreading code, that is, a Walsh orthogonal code Wk, the relation of despreading of the receiver using the QPSK demodulation method is described with respect to the received signals XI and XQ In Equation 1, if the input signal dI and dQ are orthogonally spread using the Walsh orthogonal code Wk in the system using the BPSK orthogonal modulation method, the despread relation of the receiver using the BPSK demodulation method is used. May be expressed as Equation 2 with respect to the received signals XI and XQ.

Therefore, when the modulation and demodulation schemes for generating orthogonal spreading and despreading signals are different as described above, communication is not possible because there is no backward compatibility between the two systems. That is, IS-95 terminals (including 1X terminals of the IMT-2000 system) cannot communicate with base stations of 3X (rate set 3) or higher of the IMT-2000 system, and IMT-2000 terminals (3X and higher) terminals are IS. -95 A problem arises in which communication with the base station is not possible. That is, when the base station transmits a signal spread by the QPSK modulation method in the orthogonal spreading and the terminal despreads the signal spread by the channel in the BPSK method, the relation between the input value and the output value of the demodulator is expressed by Equation 3 below. Same as

At this time, as shown in Equation 3, when the base station orthogonally spreads the transmission signal by the QPSK scheme and transmits the demodulated signal by the BPSK scheme, the base station does not use the original signal dI + jdQ. Is output. Therefore, in the above structure, receiving a QPSK modulated signal and performing BPSK demodulation causes a problem that communication between the base station and the terminal cannot be performed. In addition, in the opposite case, that is, there is a problem in that a communication function cannot be performed between a base station spreading a channel in a BPSK scheme and a terminal demodulating it in a QPSK scheme.

However, when the next generation CDMA communication system is commercialized, it is desirable to be able to service communication of existing IS-95 terminals, and it is desirable that the terminals of the IMT-2000 system also have compatibility to communicate with the base stations of the IS-95 system. Do.

In addition, in the conventional forward link of the IS-95 / IS-95A, channel division by an orthogonal code is performed as shown in FIG. 1. In FIG. 1, the Walsh orthogonal code is denoted by W, and each channel is divided by a pre-assigned orthogonal code. The IS-95 / IS-95A forward link uses a convolution code of R = 1/2, performs BPSK modulation (Biphase Shift Keying Modulation), and has a bandwidth of 1.2288MHz, thus distinguishing channel classification. For Walsh orthogonal code, 1.2288M / (9.6k * 2) = 64. Accordingly, as shown in FIG. 1, the forward link of the IS-95 / IS-95A can perform 64 channel division using an orthogonal code.

When any modulation method is determined as described above and a minimum data rate is determined, the number of available orthogonal codes is determined. However, next-generation CDMA systems (future code division multiple access systems) attempt to increase the channels allocated to real users to improve performance. To this end, the next generation CDMA system adopts a method of increasing capacity by providing a traffic channel, a pilot channel, and a control channel.

However, even in the above scheme, when the channel usage increases, the number of orthogonal codes available is limited. In this case, even if the channel capacity is increased, there is a limit to the increase in the channel capacity according to the limitation of the number of Walsh orthogonal codes that can be used. Accordingly, as a method for solving the above problem, a quasi-orthogonal code which gives a minimum interference to the orthogonal code and can also give a minimum interference to a variable data rate is used. It may be desirable to use. The application for the quasi-orthogonal code is disclosed in detail in Korean Patent Application No. 97-47457, and the prior application for the complex quasi-orthogonal code is described in Korean Patent Application No. 98-37453.

In the case of a CDMA system such as the IMT-2000 system that uses the quasi-orthogonal code of the complex quasi-orthogonal sequence, QPSK orthogonal modulation is required to perform orthogonal spreading and despreading using the complex quasi-orthogonal code. Likewise, if the orthogonal modulation method is changed to the QPSK orthogonal modulation method, and the Walsh orthogonal code is also QPSK modulated, the BPSK modulation in the spread structure is performed in the case of a specific common channel such as a pilot channel or a sync channel. There is a problem that backward compatibility with the existing IS-95 system having a scheme cannot be achieved.

Accordingly, an object of the present invention is to provide a spreading apparatus and a method in which a base station and a terminal having different channel spreading and despreading structures in a code division multiple access communication system can perform a communication function.

Another object of the present invention is to provide an apparatus and method capable of selectively performing orthogonal spreading using QPSK modulation and BPSK modulation in a code division multiple access communication system.

It is still another object of the present invention to provide an apparatus and method for performing orthogonal spreading by a base station using a BPSK modulation scheme for a specific channel in a code division multiple access communication system and a QPSK modulation scheme for other channels. In providing.

It is still another object of the present invention to provide an apparatus in which a terminal performs orthogonal despreading with a BPSK demodulation scheme for a specific channel and orthogonal despreading with other channels in a QPSK demodulation scheme in a code division multiple access communication system. And providing a method.

Another object of the present invention is to perform orthogonal spreading using a BPSK modulation scheme for a specific channel and orthogonal spreading for other channels in a code division multiple access communication system, and the terminal performs orthogonal spreading for a specific channel. The present invention provides an apparatus and a method for performing orthogonal despreading using the BPSK demodulation scheme and performing orthogonal despreading with respect to other channels using the QPSK demodulation scheme.

It is still another object of the present invention to provide an orthogonal spreading apparatus and method in which channel transmitters of a code division multiple access communication system are provided with a BPSK quadrature spreader and a QPSK quadrature spreader to selectively orthogonally spread a transmission signal.

It is still another object of the present invention to provide an orthogonal despreading apparatus and method in which channel receivers of a code division multiple access communication system are provided with a BPSK orthogonal spreader and a QPSK orthogonal spreader to selectively orthogonally despread a received signal.

It is still another object of the present invention to provide an orthogonal spreader for orthogonally spreading a transmission signal using a Walsh orthogonal code in BPSK modulation and a Walsh orthogonal or quasi orthogonal code in QPSK modulation. An orthogonal spreader for orthogonally spreading a transmission signal provides an apparatus and a method for selectively orthogonally spreading a transmission signal.

It is still another object of the present invention to provide an orthogonal spreader for despreading an orthogonal spread signal using a Walsh orthogonal code in a BPSK demodulation scheme and a Walsh orthogonal code or a quasi orthogonal code in a QPSK demodulation scheme. The present invention provides an apparatus and a method for selectively orthogonally despreading a received signal by using orthogonal spreaders that despread an orthogonally spread signal by using an orthogonal spreader.

A channel spreading apparatus of a base station of a code division multiple access communication system according to an embodiment of the present invention for achieving the above object, a spreading for generating a spreading code of a real component and a spreading code of an imaginary component corresponding to a designated channel spreading code index A code generator, a circuit for inputting a mode control signal, the circuit for turning off the generation of the imaginary component spread code when the input mode control signal is a BPSK modulation mode, a channel signal, and inputting the channel signal And a complex multiplier for channel spreading by complex multiplication of the spreading codes.

In addition, a channel despreading apparatus of a terminal of a code division multiple access communication system according to an embodiment of the present invention for achieving the above object generates a spreading code of a real component and a spreading code of an imaginary component corresponding to a designated channel spreading code index. A spreading code generator and a mode control signal, and a circuit for turning off generation of the imaginary component spreading code when the input mode control signal is a BPSK modulation mode, and a channel signal. And a complex multiplier for complex multiplication of the signal and the spreading codes.

1 is a diagram illustrating a spreader configuration of a forward link of a conventional code division multiple access communication system.

2 is a diagram illustrating a transmitter structure of a forward link for performing QPSK orthogonal code spreading and QPSK PEN code spreading in a code division multiple access communication system.

FIG. 3 is a diagram illustrating a receiver structure of a forward link in which a terminal demodulates a spread signal as shown in FIG. 2 in a code division multiple access communication system.

4 is a diagram illustrating a transmitter structure of a forward link for performing BPSK orthogonal code spreading and BPSK PEN code spreading in a code division multiple access communication system; FIG.

FIG. 5 illustrates a receiver configuration of a forward link in which a terminal demodulates a spread signal as shown in FIG. 4 in a code division multiple access communication system.

FIG. 6 is a diagram illustrating a channel required for compatibility with an IS-95 communication system according to a first embodiment of the present invention in a code division multiple access communication system using a BPSK orthogonal spreading mode and other channels using a forward QPSK orthogonal spreading mode. Link showing the configuration of transmission channel devices

FIG. 7 is a flowchart illustrating a process of performing a channel spreading operation in a code division multiple access communication system as shown in FIG. 6.

FIG. 8 is a diagram illustrating a configuration of an orthogonal code spreading device in a BPSK mode in a code division multiple access communication system having the same structure as that of FIG.

9 is a diagram illustrating a configuration of an orthogonal code spreading device in a QPSk mode in a code division multiple access communication system having the structure shown in FIG.

10 to 14 are diagrams showing the configuration of an orthogonal code spreading apparatus for performing an orthogonal spreading operation in a BPSK mode and a QPSK mode according to a second embodiment of the present invention.

FIG. 15 is a diagram illustrating a configuration of a table that stores a mask index and a Walsh orthogonal code index corresponding to a spread code index according to an embodiment of the present invention. FIG.

FIG. 16 is a diagram illustrating a configuration of a table that stores a mask index and a Walsh orthogonal code index corresponding to a spread-sign code index for generating spread codes of I and Q components according to an exemplary embodiment of the present invention.

17-21 is a diagram showing another configuration example of an orthogonal code spreading device in BPSK mode and QPSK mode according to the second embodiment of the present invention.

22 is a diagram illustrating a configuration of an orthogonal spreader using a BPSK modulation scheme in a channel receiver of a code division multiple access communication system according to an embodiment of the present invention.

23 is a diagram illustrating a configuration of an orthogonal spreader using a QPSK modulation scheme in a channel receiver of a code division multiple access communication system according to an embodiment of the present invention.

24 is a diagram showing the configuration of an orthogonal despreading apparatus for performing an orthogonal despreading operation in a BPSK mode and a QPSK mode according to a second embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same components in the figures represent the same numerals wherever possible.

In the following description, a channel spreading orthogonally with Walsh orthogonal spreading and a channel orthogonally spreading with orthogonal coding among channels spreading orthogonally with BPSK modulation and QPSK modulation orthogonally spread with QPSK modulation. Specific details such as and the like are shown to provide a more general understanding of the invention. It will be apparent to one of ordinary skill in the art that the present invention may be readily practiced without these specific details and also by their modifications.

Also in the following description, the terms "orthogonal spreading" and "channel spreading" will be used in the same sense, and the terms "PN spreading" and "band spreading" will also be used in the same sense. The term "spread code" is a term that includes "Walsh orthogonal code" and "quasi-orthogonal code", and the "spread code index" is a Walsh orthogonal code for designating a table for generating Walsh orthographic or quasi-orthogonal code, respectively. And an index of a quasi-orthogonal code mask. In addition, the term "first spreading code" means a spreading code of a real component, and the term "second spreading code" means a spreading code of an imaginary component.

In addition, in the following description, a system performing orthogonal spreading and despreading using a QPSK modulation and demodulation method will be referred to as an " IMT-2000 system. &Quot; A system performing orthogonal spreading and despreading using a BPSK modulation and demodulation method will be described. This is referred to as "IS-95 system".

In an embodiment of the present invention, a channel that requires compatibility with an IS-95 system, such as a pilot channel, a sync channel, a paging channel, and the like in a channel structure may be a "specific channel". However, it is assumed that the diffusion structure of these specific channels has a BPSK structure. In addition, as described above, channels that are not compatible with the IS-95 system (that is, channels that are not specific channels) may be “non-specific channels,” and these non-specific channels are channels used in the IMT-2000 system. The diffusion structure of these channels is assumed to have a QPSK structure. Such non-specific channels may be dedicated control channels, dedicated supplemental channels, and common channels proposed and used in the IMT-2000 system.

In addition, since the channel spreading method of the IS-95 system is despread using the Walsh orthogonal code as the BPSK modulation method, the channel spreading of the BPSK modulation method is assumed to use the Walsh orthogonal code in the embodiment of the present invention. do. In addition, the channel spreading of the QPSK modulation scheme selectively uses Walsh orthogonal codes or quasi-orthogonal codes. Therefore, the orthogonal spreader structure according to the embodiment of the present invention can perform orthogonal spreading by selecting a BPSK and QPSK modulation scheme, and the channel spreading code used when performing an orthogonal spreading function with the QPSK modulation scheme is Walsh orthogonal. Signs or quasi-orthogonal codes may be optionally used.

First embodiment

In the code division multiple access communication system according to the first embodiment of the present invention, a channel requiring compatibility with an IS-95 system in a channel structure has a BPSK structure in a spread structure, and a QPSK structure in other channels that do not require compatibility. We propose a channel structure with

6 shows the structure of a channel used in the forward link of the code division multiple access communication system according to the first embodiment.

Referring to FIG. 6, the channels used in the forward link of the IMT-2000 system include a pilot channel, a sync channel, a paging channel, a traffic channel, a common control channel. A common control channel, a dedicated control channel, a fundamental channel, a supplemental channel, and the like may be formed. Pilot channels, sync channels, paging channels, and traffic channels are the channels used in the IS-95 system, and the remaining channels become the new channels proposed in the IMT-2000 system. Accordingly, the specific channel may be all channels or some of the channels used in the IS-95 system, and the remaining channels other than the specific channel become non-specific channels.

Here, it is assumed that a specific channel requiring compatibility with the IS-95 system uses a BPSK structure as a spreading structure, and other channels use a forward channel structure having a QPSK structure.

Referring to FIG. 6, when there are channels of each type, all channels are connected to the mode controller 600 which checks whether the base station is communicating with the IS-95 terminals and assigns a spreading structure to the channels. At this time, the base station indicates the type of terminal (IS-95 terminal or IMT-2000 terminal) in the access message (Access message) that the terminal requests access to the base station whether or not the communication with the IS-95 terminals Field or a field indicating a version of the terminal. The control signal of the mode controller includes a selection signal sel for separating into real and imaginary component signals and mode control signals for determining a spreading mode of each channel transmitter.

FIG. 7 illustrates a process in which the mode controller 600 sets an orthogonal diffusion mode of each channel by analyzing an access message received from the terminal. Here, the at least some channels should have orthogonal spreaders capable of performing the BPSK and QPSK orthogonal spreading modes.

Referring to FIG. 7, in step 711, the terminal transmits a message including information for identifying the type of terminal (IS-95 terminal or IMT-2000 terminal) to the base station through an access channel. The base station receiving information of the terminal including the type of the terminal identifies the type of the terminal by checking the message of the received access channel. In step 713, the base station determines the type of the channel to which the information and the base station send the message to the terminal. Apply information to the mode controller 600. In operation 715, the mode controller 600 outputs a mode control signal for designating the orthogonal diffusion mode of each channel according to the type of the terminal. Then, each of the channels sets the orthogonal diffusion mode by the mode control signal of the mode controller 600. That is, each of the channels selects an orthogonal spreading function to be transmitted by selecting the orthogonal spreading mode of the BPSK modulation method or the orthogonal spreading mode of the QPSK modulation method by the mode control signal. When the orthogonal spreading mode is determined as described above, the base station orthogonally spreads the transmission signals in a mode (BPSK or QPSK) corresponding to the type of the terminal in step 717.

In the channel structure of FIG. 6, common channels such as a pilot channel and a synchronization channel always transmit signals of the corresponding channel to the terminals before receiving a message of the access channel from the terminal. It can also be fixed. Therefore, all IMT-2000 terminals can also be fixed in the channel spreading mode of the BPSK modulation method to demodulate some common channel signals such as pilot channel and synchronization channel signals. In addition, in the terminals of the IMT-2000 system, channels that do not need to be compatible with the IS-95 terminal may be fixed in the channel spreading mode of the QPSK modulation scheme. In addition, as described above, the IMT-2000 system may implement channels currently used in the IS-95 system using a channel spread mode of the same BPSK modulation scheme as the IS-95. In addition, channels (eg, fundamental channels) used simultaneously by the IMT-2000 system and the IS-95 system may be designated by selecting a channel spreading mode using a BPSK or QPSK modulation and demodulation scheme as needed.

Each channel transmitter of FIG. 6 should have two structures, a BPSK channel spreading structure and a QPSK channel spreading structure. However, as described above, if all base stations have a specific common channel such as a pilot channel and a synchronization channel fixed to only a BPSK channel spreading structure, the terminal has only a BPSK channel spreading structure regardless of an IS-95 or IMT-2000 method. There may be. However, if the base station is fixed only in the channel spreading structure of the QPSK method for channels newly created in the IMT-2000 such as a dedicated control channel and an additional channel and do not need to be compatible with the IS-95 terminal, the corresponding IMT-2000 method The terminal of may have only the QPSK channel spread structure.

2 to 5, which will be described below, illustrate the structure of a channel transmitter and a channel receiver according to an embodiment of the present invention. 2 and 4 show channel structures of a forward link according to an embodiment of the present invention. 2 is a diagram illustrating a configuration of a channel transmitter having a QPSK modulation channel spreading structure, and FIG. 4 is a diagram of a channel transmitter having a channel spreading structure using a BPSK modulation channel. It is a figure which shows. Secondly, FIGS. 3 and 5 illustrate the structure of a channel receiver of a forward link. 3 is a diagram illustrating a configuration of a channel receiver having a QPSK demodulation channel structure in which the orthogonal code despreader 321 is a channel structure of the QPSK demodulation method, and FIG. 5 is a diagram of a channel transmitter having a channel spreading structure of the BPSK demodulation method. It is a figure which shows a structure.

Referring to FIG. 2, a signal applied to the demultiplexer 200 is a signal after channel coding, rate matching, and interleaving are performed. In addition, the selection signal sel of the demultiplexer 200 is a signal output from the mode controller 600. The demultiplexer 200 performs a demultiplexing operation when the QPSK mode is used to separate the input signal a into odd and even signals aI and aQ. After that, control is applied to the signal converters 211 and 213, respectively. Accordingly, the multiplexer 200 divides the input signal a into odd and even signals aI and aQ by the selection signal sel.

The signal converter 211 inputs an input signal aI, converts 0 to +1, converts 1 to -1, and outputs it as dI. The signal converter 213 inputs an input signal aQ, converts 0 to +1, converts 1 to -1, and outputs it as dQ. The orthogonal code spreader 215 determines the modulation scheme of the spreading code according to the mode control signal output from the controller 600. The orthogonal code spreader 215 includes generators for generating real and imaginary spread codes, and generates spread codes corresponding to the received spread code indexes k1 and k2. The orthogonal code spreader 215 inputs the signals dI and dQ and the spreading code indices k1 and k2 output from the signal converters 211 and 213, respectively, and the dI and corresponding to orthogonal codes corresponding to the spreading code indices k1 and k2, respectively. The complexes are then multiplied by dQ to generate quadrature spread signals XI and XQ. In FIG. 2, the orthogonal code spreader 215 assumes that the mode control signal designates a QPSK modulation mode. In this case, in the orthogonal code spreader 215, the spreading code generated by the spreading code index k1 becomes the spreading code of the real component, and the spreading code generated by the spreading code index k2 becomes the spreading code of the imaginary component. When the spreading code is a Walsh orthogonal code, the orthogonal spreading signal output from the orthogonal code spreader 215 becomes [XI + jXQ = (dI + jdQ) * (Wk + jWk)].

The PEN code generator 217 generates a PN code PNI and PNQ for spreading the quadrature spread signals XI and xQ. The PN code may be a short PN sequence. The PNC masking unit 219 generates the spread signals YI and YQ by complex spreading the orthogonal spread signals XI and XQ with the PEN codes PNI and PNQ. [YI + YQ = (PNI + jPNQ) * (XI + jXQ)]. The baseband filter 221 filters the spread spectrum signal YI into the baseband, and the baseband filter 223 filters the spread spectrum signal YQ into the baseband and outputs the result. The mixer 225 multiplies the output of the baseband filter 221 by the carrier cos2πfct to convert the RF signal. The mixer 227 multiplies the output of the baseband filter 223 by the carrier sin2πfct and outputs the converted RF signal. The adder 229 adds the outputs of the mixers 225 and 227 and outputs them as a transmission signal.

As shown in FIG. 2, first, aI and aQ having values of the input signals 0 and 1 are input to the signal converters 211 and 213 and converted into signals dI and dQ having values of +1 and -1, respectively. Orthogonal code spreader 215 inputs a spreading code index k for orthogonally spreading these signals together with dI and dQ. At this time, if the signal (2 SYMBOL) dI and dQ inputted to the orthogonal code spreader is expressed as a complex value, it becomes dI + jdQ, which is multiplied by the complex Walsh orthogonal code Wk + jWk, so that XI + jXQ = ( dI + jdQ) * (Wk + jWk) is output by the number N of orthogonal codes.

Therefore, in the case of FIG. 2, the channel transmitter orthogonally spreads the input signal by the QPSK modulation method, and the multiplexer 200 multiplexes the input signal a by aI and aQ and outputs the multiplier.

FIG. 3 is a diagram illustrating a configuration in which a forward channel receiver receives a signal output from a channel transmitter of a forward link as shown in FIG. 2 and de-spreads a channel in a QPSK scheme and then demodulates it.

Referring to FIG. 3, the mixer 311 mixes a carrier cos2? Fct with the received signal, and the mixer 313 mixes the carrier sin2? Fct with the received signal and outputs the mixed signal. The baseband filter 315 filters the signal output from the mixer 311 into the baseband, and the baseband filter 317 filters and outputs the signal output from the mixer 313 into the baseband.

The PEN code generator 318 generates PEN codes PNI and PNQ for despreading the received spread signal. The PNA masking unit 319 generates despread signals XI and XQ by multiplying YI and YQ output from the baseband filters 315 and 317 with the PEN code PNI and PNQ, respectively. [XI + XQ = (PNI-jPNQ) * (YI + YQ)].

The orthogonal code despreader 321 is assigned a demodulation mode (BPSK OR QPSK) for orthogonal despreading by a control signal output from a controller (not shown) in the terminal, and Walsh corresponding to the despread signals XI and XQ. Enter the orthogonal index k. At this time, the orthogonal code despreader 321 generates a spreading code of a real component and a imaginary spreading component corresponding to the spreading code index k. The signals XI and XQ input according to the designated demodulation mode are multiplied by the spreading codes corresponding to the real and imaginary components, respectively, to generate channel despread signals dI and dQ. In this case, the orthogonal despread result may be expressed as [2 * (dI + jdQ) = Σ (XI + jXQ) * (Wk-jWk)].

The signal converter 323 converts +1 to 0 and -1 to 1 in dI output from the orthogonal code despreader 321 and outputs the result. The signal converter 325 converts +1 to 0 and -1 to 1 in dQ output from the orthogonal code despreader 321. The signals output from the signal converters 323 and 325 are applied to the multiplexer 300, and the multiplexer 200 controls the output of the demodulation signals aI and aQ signals output from the signal converters 323 and 325 by the control signal SEL of the controller. do. That is, in the QPSK mode, the multiplexer 300 multiplexes the aI and aQ signals and outputs the multiplexed signals. The signal output from the multiplexer 300 is applied to the combiner of the rear stage and used as a channel estimation signal.

In FIG. 3, the P & N masking unit 319 and the orthogonal code despreader 321 illustrate a single finger configuration, and the P & M masking unit 319 and the orthogonal code despreader 321 are used to estimate a channel in the terminal. A plurality of fingers are provided.

Looking at the despreading process of the terminal, the signals XI and XQ output from the PNS masking unit 319 are first input to the orthogonal code despreader 321, and the spreading code indices k1 and k2 are input. At this time, the spreading code index k is known in advance between the terminal and the base station. It is assumed here that the spreading code is Walsh orthogonal code. When the signals XI and XQ inputted to the orthogonal code despreader 321 are expressed as complex values, XI + jXQ is a complex conjugate of Wk + jWk, which is a Walsh orthogonal code on a complex, and Wk-jWk. Multiply. If the above operation value is accumulated while operating such an operation for N times, twice the input value of the modulation process of FIG. 2 is obtained. Therefore, the despreader outputs the accumulated values. When N is 1 in the demodulation process, a relation between an input value and an output value is expressed by Equation 1 above.

4 is a diagram illustrating a configuration of a channel transmitter having a channel spreading structure using a BPSK modulation scheme in a code division multiple access communication system. The configuration of the channel transmitter of the base station as shown in FIG. 4 has the same configuration as that of FIG. 2 except for the configuration of the orthogonal code spreader 400. That is, the orthogonal code spreader 400 performs a channel spread function in a BPSK structure. In this case, the mode controller 600 outputs control signals for operating in the BPSK mode to the multiplexer 402 and the quadrature spreader 400, respectively.

Referring to FIG. 4, first, a signal applied to the demultiplexer 402 becomes a signal after channel coding, rate matching, and interleaving are performed. When the mode multiplexer 402 outputs a signal for selecting the BPSK mode, that is, when 1X and IS-95 are compatible, all of the input signals a are input to the signal converter 211 and the signal converter 213 is used. Do not input any signal. Accordingly, a having a value of 0 and 1 output from the demultiplexer 402 is input to the signal converter 211 to output a signal dI having a value of +1 and -1 and dQ having a value of 0, and the quadrature spreader 400 is The BPSK modulation mode is designated by the mode control signal, and after inputting a spreading code index k for orthogonal spreading together with the signals dI and dQ, a corresponding spreading code is generated and orthogonally spread by the BPSK scheme. In this case, when the signals dI and dQ inputted to the quadrature code spreader 400 are expressed as complex values, it becomes dI + jdQ, and this value is multiplied by the complex Walsh orthogonal code Wk so that XI + jXQ (= (dI + jdQ). ) X Wk) is output N times.

FIG. 5 is a diagram illustrating a configuration in which a terminal receives and demodulates a spread signal output from a transmitter of a base station having an orthogonal spreader having a BPSK structure as shown in FIG. 4. Here, the receiver of FIG. 5 and the terminal have the same configuration as that of FIG. 3 except for an orthogonal code despreader 500. That is, the orthogonal code despreader 500 performs a channel despreading function of the BPSK structure. Herein, it is assumed that the mode control signal applied to the orthogonal code despreader 500 of FIG. 5 designates a BPSK demodulation mode, and the multiplexer 502 is configured to select an aQ signal output from the signal converter 325 in the BPSK demodulation mode by the selection signal sel. Shut off the output.

Referring to FIG. 5, the signals XI and XQ output from the PNS mask 319 are input to an orthogonal code despreader 500, and a spread code index k is input at the same time. At this time, the Walsh index k is information that the terminal knows in advance with the base station. Then, the orthogonal code despreader 500 is designated as a BPSK demodulation mode by a control signal outputted from a controller (not shown) of the terminal, and generates a spread code corresponding to the spread code index k to despread the input orthogonal spread signal. do. In this case, when the signals XI and XQ are expressed as complex values, XI + jXQ is multiplied by the same Walsh code Wk. When the operation is accumulated for N times and the calculated value is accumulated, the input value of the modulation process of FIG. 4 is obtained. Therefore, the orthogonal code despreader 500 outputs the accumulated values. When N is 1 in the demodulation process, the relation between the input value and the output value is expressed by Equation 2 above.

In the CDMA communication system performing channel spreading and despreading function using Walsh orthogonal code as described above, the IS-95 system uses the orthogonal spreading method of the BPSK structure and the IMT-2000 system uses the orthogonal spreading method of the QPSK structure. Can be. In this case, the base station of the IMT-2000 system and the terminal of the IS-95 system or the base station of the IS-95 system and the terminal of the IMT-2000 system cannot perform a communication function.

As described above, when the channel transmitters and the channel receivers of the forward link are configured as described above, for example, when the IS-95 terminal appears in the IMT-2000 base station, the base station is a spread structure of the common channels such as the pilot and the sync channel. In Fig. 4 showing the BPSK structure, the demultiplexer inputs all the signals after channel coding, rate matching, and interleaving to the signal converter 211, and the signal converter 213. After inputting no signal, the above process is performed and is compatible with IS-95 terminal so that the IS-95 terminal can receive the signal sent by the base station, and the IS-95 terminal can try to make a call. When the access message including the message indicating the terminal is transmitted to the base station, the base station receives the message and confirms that the type of the terminal is IS-95. All signals sent to the terminal are sent in the same manner as described above.

In addition, when the IMT-2000 terminal appears in the IS-95 base station, the terminal first operates the spreading structure in the BPSK mode to receive common channels such as a pilot channel and a sink channel. In FIG. 5 illustrating the BPSK structure, the multiplexer inputs only the signal output from the signal converter 323 among the signals after despreading and signal conversion and outputs the same, and then performs the decoding process. It is compatible with the IS-95 base station so that the IS-95 base station can receive the signal sent to the terminal, and when the terminal sends an access message to the base station to attempt a call, the base station receives the message and the type of base station When a channel assignment message including a message indicating that the base station is an IS-95 is transmitted, the terminal determines that the type of the base station is the base station IS-95 and receives all subsequent signals in the same manner as described above.

8 and 9 illustrate a quadrature spreader structure of the BPSK and QPSK modulation schemes. Therefore, each channel transmitter according to an embodiment of the present invention should be able to perform orthogonal code spreading of two modulation schemes as shown in FIGS. 8 and 9. The orthogonal code spreading method includes two or more spreaders as shown in FIGS. 8 and 9 and selects a corresponding orthogonal code spreader according to a designated mode. After the configuration, the BPSK and QPSK schemes can be selectively controlled by controlling the diffusion code of the imaginary component. In the embodiment of the present invention, it is assumed that the orthogonal diffusion function is performed based on the latter method.

First, FIG. 8 shows a configuration of an orthogonal spreading PN spreading in the BPSK mode. FIG. 8 illustrates a configuration of an orthogonal code spreader 400 of FIG.

Referring to FIG. 8, the spreading code generator 811 includes a spreading code table. When the spreading code index k is input, the spreading code generator 811 selects and generates a spreading code corresponding to the index k. Multiplier 813 multiplies the input signal dI by the spreading code to generate an orthogonally spread I-channel signal XI. Multiplier 815 multiplies the input signal dQ by the spread signal to generate an orthogonally spread Q channel signal XQ.

Referring to FIG. 8, the operation of the orthogonal code spreader 400 of the BPSK modulation scheme is described. First, the input signals dI and dQ are input to the multipliers 813 and 815. At the same time, if a spreading code index k for which spreading code is to be input to the spreading code generator 811, the spreading code generator 811 generates a spreading code corresponding to the spreading index index k and applies it to the multipliers 813 and 815. At this time, the multiplier 813 multiplies the input signal dI by the spreading code to output the output signal XI, and the multiplier 830 multiplies the input signal dQ by the spreading code to generate the output signal XQ.

Fig. 2 shows the structure of a transmitter in QPSK mode. FIG. 9 shows a configuration of an orthogonal code spreader 215 in the structure of the QPSK transmitter as shown in FIG.

Referring to FIG. 9, the first spreading code generator 911 and the second spreading code generator 913 input a spreading code index k and generate a first spreading code and a second spreading code corresponding to the spreading code index k, respectively. . Here, the first spreading code and the second spreading code generated by the first spreading code generator 911 and the second spreading code generator 913 become a spreading code of the I component and a spreading code of the Q component, respectively. The multiplier 915 multiplies the input signal dI by a spread code generated by the first spreading code generator 911 and outputs the multiplied signal. The multiplier 917 multiplies the input signal dQ by the spreading code generated by the first spreading code generator 911 to output the multiplier. It can be seen that the structure of the first spreading code generator 911 and the multipliers 915 and 917 is the same as the structure of the orthogonal code spreader of the BPSK scheme as shown in FIG. 8. The multiplier 919 multiplies the second spreading code output from the second spreading code generator 913 and the input signal dI and outputs the multiplier. The multiplier 921 multiplies the second spreading code output from the second spreading code generator 913 and the input signal dQ to output the multiplier. An adder 923 subtracts the output of the multiplier 921 from the output of the multiplier 915 to generate an output signal XI. The adder 925 adds the output of the multiplier 919 and the output of the multiplier 917 to generate an output signal XQ.

Referring to the operation of the QPSK quadrature code spreader as shown in FIG. 9, first, input signals XI are input to multipliers 915 and 919, and input signals XQ are input to multipliers 917 and 921. FIG. At the same time, the spreading code index k for which spreading code to use is input to the I-component spreading code generator 900 and the Q-component spreading code generator 905, respectively, and outputs the I-component and Q-component spreading codes corresponding to the spreading-code index. Then, the output I component spreading codes are input to the multipliers 915 and 917, and the multiplier 915 multiplies the input I component input signals XI and the I component spreading codes and applies them to the adder 923. The multiplier 917 multiplies the input Q component input signal XI with the I component spreading code and applies it to the adder 925. At this time, the output Q component diffusion codes are input to the multipliers 919 and 921, and the multiplier 919 multiplies the input I component input signals XI and Q component diffusion codes and applies them to the adder 925. The adder 925 adds the output signal of the multiplier 919 to the signal output from the multiplier 917 to output the output signal SQ. At the same time, the multiplier 921 multiplies the input Q component input signal XQ by the Q component diffusion code and applies it to the adder 923. The adder 923 subtracts the output signal of the multiplier 921 from the signal output from the multiplier 915 to generate a signal SI.

FIG. 10 is a diagram showing the configuration of a spreading code generator in the configuration of an orthogonal code spreader as shown in FIGS. 8 and 9 above.

Herein, the structure and generation method of the quasi-orthogonal code are disclosed in detail in Korean Patent Application No. 97-47457 filed with the applicant. However, the pre-patent patent is for non-escaping modulation, in which the sequences of the patent are odd powers of length 2 in the correlation characteristics of the sequences. The correlation for to be. In addition, a complex quasi-orthogonal function for QPSK modulation is disclosed in detail in Korean Patent Application No. 98-37453 filed by the applicant. The complex quasi-orthogonal sequence of Patent Application No. 98-37453 has an odd power of length 2 which is a problem of the quasi-orthogonal sequence for the BP modulation. Correlation for Has Therefore, it can be said that it has very excellent property from a correlation degree point of view.

Referring to FIG. 10, the controller 1011 calculates and outputs a mask index and a Walsh orthogonal code index for generating a quasi-orthogonal code corresponding to the spread code index when the spread code index k is input. The mask generator 1013 includes a mask index table, and selects and outputs a quasi-orthogonal code mask corresponding to the mask index from the table. The Walsh orthogonal code generator 1015 includes a Walsh orthogonal code table, and generates a Walsh orthogonal code corresponding to the Walsh orthogonal code index from the table. Multiplier 1017 multiplies the quasi-orthogonal code mask with the Walsh orthogonal code to generate a spreading code. If the mask index is not selected, the mask generator 1013 does not generate the quasi-orthogonal code mask, and the multiplier 1017 outputs a Walsh orthogonal code output from the Walsh orthogonal code generator 1015 as a spread code. When the mask generator 1013 outputs a quasi-orthogonal code mask, the diffusion code output by the multiplier 1017 becomes a quasi-orthogonal code.

At this time, in FIG. 9, the diffusion code generator includes a diffusion code generator of I component representing a real code diffusion code and a Q component diffusion code representing an imaginary component diffusion code. In the complex quasi-orthogonal sequence having the structure as follows, the spreading index index input to each of the spreading code generators, the mask index input to the mask index in the spreading code generator, the Walsh orthogonal code index input to the Walsh orthogonal code generator, The Walsh orthogonal code, which is the output value for the input of the wall start code index, is the same, while the mask value, that is, the mask value of the I component diffusion code and the Q component diffusion code, may be different from each other. Since the mask values of the I component mask generator 1013 and the mask values of the Q component mask generator 1013 have different memories, the I component mask output and the Q component mask output are different even when the same mask index is received. In the implementation, the memory having the mask value may be implemented by hardware generating mask values according to indes.

Referring to FIG. 10, when the spreading code index is input to the controller 1011, the controller 1011 calculates and outputs a mask index and a Walsh code index corresponding to the spreading code index. The mask index is input to the mask generator 1013 and the Walsh orthogonal code index is input to the Walsh orthogonal code generator 1015. At this time, the mask generator 1013 generates a mask signal represented by 1 and -1 and outputs the mask signal represented by 1 and -1 to the multiplier 1017, and the Walsh orthogonal code generator 1017 generates and outputs a Walsh orthogonal code represented by 1 and -1. To apply. The multiplier 1017 multiplies the quasi-orthogonal code mask with the Walsh orthogonal code and outputs a diffusion code. The diffusion code may be a Walsh orthogonal code or a quasi-orthogonal code. At this time, the structure of the diffusion code generator is a structure when the mask value output from the mask generator and the Walsh orthogonal code output from the Walsh orthogonal code generator are output as values of 1 and -1. If the mask value output from the mask generator and the Walsh orthogonal code output from the Walsh orthogonal code generator are output as 0 and 1, an adder is used instead of the multiplier 1017 to add the two output values and then add the values 1 and -1. It may be made of a structure that outputs after converting the signal.

FIG. 15 illustrates a mask index table of a quasi-orthogonal code and an index table of the Walsh orthogonal code according to the spreading code index k in the spreading code generator having the configuration as shown in FIG. 10. Referring to the operation of generating the Walsh orthogonal code in the diffusion code generator having the structure as shown in FIG. 10, the mask index is set to 0, which is a specific value (the specific value may be changed by a system variable), and the mask The generator 1013 receives this index and always sends a signal of 1. Accordingly, the Walsh orthogonal code generator generates Walsh orthogonal code corresponding to the Walsh orthogonal code index generated by the Walsh orthogonal code generator 1015 and outputs the spreading code. In addition, referring to the operation of generating a quasi-orthogonal code in the spreading code generator having the structure as shown in FIG. 10, when the spreading code index k is input, the controller 1011 generates a mask index and a Walsh orthogonal code index for generating a desired quasi-orthogonal code. Then, the mask generator 1013 selects and outputs a mask corresponding to the mask index from the mask index table as shown in FIG. 15, and the Walsh orthogonal code generator 1015 generates a Walsh orthogonal code corresponding to the Walsh orthogonal code index. Selective output. Then, the mask of the quasi-orthogonal code and the Walsh orthogonal code are mixed in a multiplier 1017 to generate a quasi-orthogonal code.

In the channel structure of FIG. 6, each channel should be able to support the above two spreading structures (BPSK and QPSK modulation modes). In this way, two hardware structures are required. Alternatively, we can think of a structure where the structure can be changed according to the mode designation command with one piece of hardware. In the following second embodiment, a structure of an orthogonal code spreader capable of performing an orthogonal spreading function in two modulation modes (BPSK and QPSK) will be described.

Second embodiment

11 to 14 are diagrams for a method having a BPSK or QPSK structure by using a switch or adjusting power of an input signal according to a position to block or connect a Q component spread signal.

First, referring to FIG. 11, except for the configuration for selecting the BPSK path and the QPSK path according to the mode control signal of the mode controller 600, the configuration of the orthogonal code spreader of the QPSK modulation method shown in FIG. 9 is the same. That is, FIG. 11 further shows a switch 1111 connected between the multiplier 919 and the adder 925 and switching controlled by the mode control signal, and a switch 1113 connected between the multiplier 921 and the adder 923 and controlled by the mode control signal. Equipped. At this time, the switches 1111 and 1113 are controlled simultaneously.

Referring to the operation of the orthogonal code spreader as shown in FIG. 11, if the channel spreading structure is BPSK, the Q component spreading code is applied to the signal dI output from the multiplier 919 and the signal dQ output from the multiplier 921 by disconnecting the switches 1111 and 1113, respectively. The output signals after multiplying are not applied to the adder 925 and the adder 923. Thus, the adder 925 and adder 923 subtracts and adds zeros instead of the spread signals of the Q component, respectively. Therefore, when the output signals XI and XQ are output, signals output from the same structure as the BPSK structure are output, thereby generating an orthogonal spreading signal of the BPSK modulation scheme having the structure shown in FIG. 9.

If the channel diffusion structure is QPSK, the switches 1111 and 1113 connect the multiplier 919 and the adder 925, and the multiplier 921 and the adder 923, respectively, so that the signal output from the multiplier 919 is output from the multiplier 919. The output signals after multiplying the Q component diffusion codes by dQ are applied to the adder 925 and the adder 923, respectively. Therefore, as shown in FIG. 9, an orthogonal spread signal of the QPSK modulation method is generated.

Secondly, referring to FIG. 12, except for the configuration for selecting the BPSK path and the QPSK path according to the mode control signal of the mode controller 600, the configuration of the orthogonal code spreader of the QPSK modulation scheme as shown in FIG. 9 is the same. That is, referring to the configuration of the orthogonal code spreader as shown in FIG. 12, the gain controller 1211 generates the first gain control signal in the BPSK mode and the second control signal in the QPSK mode according to the mode control signal output from the mode controller 600. Occurs. A multiplier 1213 is connected between the multiplier 919 and the adder 925, the gain is controlled by the gain control signal to control the output gain of the multiplier 919. A multiplier 1215 is connected between the multiplier 921 and the adder 923 to control the output gain of the multiplier 921 by the gain control signal. In this case, the gain control signals applied to the multipliers 1213 and 1215 have the same value. The first gain control signal is set to 0 to block the spread of the Q component from being applied to the adders 925 and the adder 923, and the second gain control signal is set to 1 so that the spreading signal of the Q components is added to the adders 925 and adders 923. It can be applied as it is.

Referring to the operation of the orthogonal code spreader as shown in FIG. 12, if the channel spreading structure is BPSK, a mode control signal indicating that the spreading structure is BPSK is applied to the gain controller 1211. In this case, the gain controller 1211 has a first value having a zero value. The gain control signal will continue to output 0. Then, 0, which is a value for controlling the gain, is input to the multipliers 1213 and 1215 and multiplied, respectively, so that the multipliers 1270 and 1272 both output 0. Therefore, since 0 is output from the multipliers 1213 and 1215, the adders 925 and adders 923 subtract and add 0 and the spread signals of the corresponding I component, respectively. Therefore, in the following output signal, the signal output from the same structure as that of the BPSK structure is output, resulting in an orthogonal spreading signal having the BPSK structure as shown in FIG.

In addition, if the channel diffusion structure is QPSK, a mode control signal indicating that the diffusion structure is QPSK is applied to the gain controller 1211. In this case, the gain controller 1211 continuously outputs 1, which is a second gain control signal, and the gain controller Values of 1 output from 1211 are input to multipliers 1213 and 1215, respectively. Then, after the Q component spreading codes are multiplied by the signal dI output from the multiplier 919 and the signal dQ output from the multiplier 921, the output signals are multiplied by a gain control value of 1 in the multipliers 1213 and 1215, respectively. The losing values have the same value as the output signals of multipliers 919 and 921. Therefore, the output value of the multiplier 1213 is applied to the adder 925, and the output value of the multiplier 1215 is input to the adder 923, respectively. Accordingly, the adder 923 subtracts the output of the multiplier 921 from the output of the multiplier 915 to output the quadrature spread signal XI, and the adder 925 adds the output of the multiplier 917 and the output of the multiplier 919 to output the quadrature spread signal XQ. Therefore, the output orthogonal spread signal is outputted with the same spread signal as the QPSK spread structure shown in FIG. 9.

Thirdly, referring to FIG. 13, except for the configuration for selecting the BPSK path and the QPSK path according to the mode control signal of the mode controller 600, the configuration of the orthogonal code spreader of the QPSK modulation method as shown in FIG. That is, FIG. 13 is connected between the output terminal of the second spreading code generator 913 and the multipliers 919 and 921 and further comprises a switch 1311 for switching control by the mode control signal to control the output of the second spreading code of the Q component. Equipped.

Referring to the operation of the orthogonal code spreader having the configuration as shown in FIG. 13, if the channel spreading structure is BPSK, the switch 1311 is switched off to generate the second spreading code of the Q component in the multipliers 919 and 921. The passage is blocked. As a result, the multiplier 919 outputs 0 by multiplying the input signal dI by 0, and the output values of 0 are added to the adder 925, so that the adder 923 equals the output value of the multiplier 917. Will print. In addition, the multiplier 921 also outputs a value of 0 by multiplying the input signal dQ by 0, and the zero values thus output are further subtracted to the adder 923, so that the adder outputs the same value as the output value of the multiplier 915. . Thus, the final output values to the operation will be the same as the output values in the BPSK.

When the diffusion structure of the channel is QPSK, the switch 1311 is connected, and the second spreading code of the Q component generated by the second spreading code generator 913 is normally applied to the multipliers 919 and 921 by the connection of the switch 1311. Subsequently, the subsequent operation is the same as that of FIG. 9 to generate an orthogonal spreading signal of QPSK modulation.

Fourth, referring to FIG. 14, the configuration is the same as that of the QPSK modulation scheme orthogonal code spreader as shown in FIG. 9 except for the configuration for selecting the BPSK path and the QPSK path according to the mode control signal of the mode controller 600. That is, FIG. 14 is connected between a gain controller 1211 for generating a gain control signal according to a mode control signal, an output terminal of the second spreading code generator 913, and multipliers 919 and 921, and the Q component by the gain control signal. And a multiplier 1411 for controlling the output of the second spreading code.

Referring to the operation of the orthogonal code spreader having the configuration as shown in FIG. 14, if the channel spreading structure is BPSK, the gain controller 1211 generates a first gain control signal having a value of zero by the mode control signal. The multiplier 1411 multiplies the output of the second spreading code generator 913 by 0, thereby blocking the output passage of the spreading code generator 913 which generates the second spreading code of the Q component in the multipliers 919 and 921. As a result, the multiplier 919 outputs 0 by multiplying the input signal dI by 0, and the output values of 0 are added to the adder 925, so that the adder 925 is equal to the output value of the multiplier 917. Will print. In addition, the multiplier 921 also outputs a value of 0 by multiplying the input signal dQ by 0, and the zero values thus output are added to the adder 923, so that the adder outputs the same value as the output value of the multiplier 915. . Thus, the final output values to the operation will be the same as the output values in the BPSK.

If the channel diffusion structure is QPSK, the gain controller 1211 generates a second gain control signal having a value of 1 by the QPSK mode control signal. The multiplier 1411 multiplies the output of the second spreading code generator 913 by 1, and the multipliers 919 and 921 input the second spreading code of the Q component generated by the second spreading code generator 913. Subsequently, the subsequent operation is the same as that of FIG. 9 to generate an orthogonal spreading signal of QPSK modulation.

11 to 14 are four orthogonal codes having a BPSK or QPSK structure by controlling a spreading code of a Q component by using a switch or controlling a gain of an input signal (ie, adjusting transmission power) according to a position. It shows how to spread it. In the following, the diffusion structure is different from that described above in FIG. 9, and a method of selectively using the BPSK and QPSK structures using the diffusion code index is provided.

FIG. 16 shows an I component mask index, a Q component mask index, and a Walsh code index according to the spread code index as shown in FIG. If the BPSK structure is designated as the mode designation, the value I between (N + 1) * 128 and (N + 2) * 127 in FIG. Inputs to generator 911 and second spreading code generator 913 of Q components. At this time, referring to Figure 10 for the operation of the Q component orthogonal code spreader, first, the input spread code index is input to the controller 1011, the controller 1011 is a mask index T and Walsh orthogonal code according to the spread code index P The index is calculated and the mask index T is input into the mask generator 1013, and the Walsh orthogonal code index is input into the Walsh orthogonal code generator 1015. In this case, the mask index T causes the mask generator 1013 to output a mask having all zero mask values, thereby multiplying the multiplier 1017 by zero. Therefore, since the output of the first spreading code generator 913 of the Q component becomes 0, it becomes the same as the BPSK process in the subsequent process of the spreading code generator in FIG.

17 to 21 illustrate examples of orthogonal spreading in a BPSK and QPSK scheme in a manner different from those of FIGS. 11 to 14. 17 to 21 illustrate a structure in which orthogonal code spreads using a BPSK or QPSK modulation scheme by controlling the output of a spreading code generator. 17 to 21 control the output of the diffusion code by controlling the output of the mask generator 1013 or the Walsh orthogonal code generator 1015, and this configuration becomes the structure of the second spreading code generator 913. That is, in the orthogonal code spreader having the structure as shown in FIG. 9, the first spreading code generator 911 has the structure as shown in FIG. 10, and the second spreading code generator 913 has the structure as shown in FIGS. 17 to 21.

17-21 has a structure similar to that of FIG. 10, and controls the output of the second spreading code generator 913 by a mode control signal output from the mode controller 600, thereby providing a QPSK mode control signal. At this time, the output of the second spreading code generator 913 is normally output, and when the BPSK mode control signal is output, the output of the second spreading code generator 913 is blocked.

FIG. 17 further includes a switch 1711 between the mask generator 1013 and the multiplier 1017 in the configuration of the diffusion code generator as shown in FIG. 10. Accordingly, when the BPSK mode control signal is generated, the switch 1711 is turned off, and a value of 0 is applied to the multiplier 1017 to output a diffusion code of zero. Accordingly, the outputs of the multipliers 919 and 921 of FIG. 9 become 0 to perform the orthogonal diffusion operation in the BPSK mode. However, when the QPSK mode control signal is generated, since the switch 1711 is turned on, the output of the mask generator 1013 is applied to the multiplier 1017. Therefore, the output of the Walsh orthogonal code generator 1015 and the quasi orthogonal code mask are multiplied to generate a spread code. Therefore, the orthogonal diffusion operation of the BPSK mode and the QPSK mode can be selectively performed.

FIG. 18 further includes a switch 1811 between the Walsh orthogonal code generator 1015 and the multiplier 1017 in the configuration of the spreading code generator shown in FIG. 10. Therefore, when the BPSK mode control signal is generated, the switch 1811 is turned off, and a value of 0 is applied to the multiplier 1017 to output a diffusion code of zero. Accordingly, the outputs of the multipliers 919 and 921 of FIG. 9 become 0 to perform the orthogonal diffusion operation in the BPSK mode. However, when the QPSK mode control signal is generated, since the switch 1811 is turned on, the output of the Walsh orthogonal code generator 1015 is applied to the multiplier 1017. Therefore, the output of the Walsh orthogonal code generator 1015 and the quasi orthogonal code mask are multiplied to generate a spread code. Therefore, the orthogonal diffusion operation of the BPSK mode and the QPSK mode can be selectively performed.

FIG. 19 illustrates a multiplier 1911 connected between a mask generator 1013 and a multiplier 1017 and a gain controller 1211 that analyzes the mode control signal and outputs a gain control signal to the multiplier 1911 in the configuration of the diffusion code generator as shown in FIG. 10. It is further provided. Therefore, when the BPSK mode control signal is generated, the gain controller 1211 outputs a value of 0, and thus the output of the multiplier 1911 is also 0. Thus, a value of 0 is applied to the multiplier 1017 to output a diffusion code of zero. Accordingly, the outputs of the multipliers 919 and 921 of FIG. 9 become 0 to perform the orthogonal diffusion operation in the BPSK mode. However, when the QPSK mode control signal is generated, the gain controller 1211 outputs 1, which causes the multiplier 1911 to apply a quasi-orthogonal code mask output from the mask generator 1013 to the multiplier 1017. Therefore, the output of the Walsh orthogonal code generator 1015 and the quasi orthogonal code mask are multiplied to generate a spread code. Therefore, the orthogonal diffusion operation of the BPSK mode and the QPSK mode can be selectively performed.

20 is a multiplier 2011 connected between a Walsh orthogonal code generator 1015 and a multiplier 1017 in the configuration of a spreading code generator as shown in FIG. 10, and a gain controller for analyzing a mode control signal and outputting a gain control signal to the multiplier 2011. 1211 is further provided. Therefore, when the BPSK mode control signal is generated, the gain controller 1211 outputs a value of 0, so that the multiplier 2011 also outputs a value of 0. Thus, a value of 0 is applied to the multiplier 1017 to output a diffusion code of zero. Accordingly, the outputs of the multipliers 919 and 921 of FIG. 9 become 0 to perform the orthogonal diffusion operation in the BPSK mode. However, when the QPSK mode control signal is generated, the gain controller 1211 outputs a value of 1, which causes the multiplier 2011 to apply the output of the Walsh orthogonal code generator 1015 to the multiplier 1017. Therefore, the output of the Walsh orthogonal code generator 1015 and the quasi orthogonal code mask are multiplied to generate a spread code. Therefore, the orthogonal diffusion operation of the BPSK mode and the QPSK mode can be selectively performed.

21 further includes a gain controller 1211 for analyzing the mode control signal and outputting a gain control signal to the multiplier 1017 in the configuration of the spreading code generator as shown in FIG. Accordingly, since the gain controller 1211 outputs a value of 0 when the BPSK mode control signal is generated, the output of the multiplier 1017 is also 0, and thus, the spreading code that is output is also 0. Accordingly, the outputs of the multipliers 919 and 921 of FIG. 9 become 0 to perform the orthogonal diffusion operation in the BPSK mode. However, when the QPSK mode control signal is generated, the gain controller 2011 outputs a value of 1. As a result, the multiplier 1017 multiplies the output of the Walsh orthogonal code generator 1015 and the quasi-orthogonal code mask to generate a spread code. Therefore, the orthogonal diffusion operation of the BPSK mode and the QPSK mode can be selectively performed.

12, 14, 19, 20, and 21 performing the orthogonal spreading function of the QPSK mode and the BPSK modulation mode using the gain controller and the multiplier in the above configuration, the mode controller 600 is configured in the BPSK mode. When generating a mode control signal having a value of 0 and generating a mode control signal having a value of 1 in the QPSK mode, it is not necessary to use separate gain controllers. That is, when the mode control signal is directly applied to the corresponding multiplier, a BPSK path or a QPSK path may be formed according to the corresponding mode.

FIG. 22 illustrates a configuration of an orthogonal code despreader 500 of FIG.

Referring to FIG. 22, the spreading code generator 2211 includes a spreading code table. When the spreading code index k is input, the spreading code generator 2211 selects and generates a spreading code corresponding to the index k. Multiplier 2213 multiplies the orthogonally spread input signal XI by the spreading code to generate an orthogonal despread I-channel signal dI. Multiplier 2215 multiplies the orthogonally spread input signal XQ by the spread signal to generate an orthogonal despread Q channel signal dQ.

Referring to FIG. 22, the operation of the orthogonal code spreader 500 of the BPSK demodulation method is described. First, the input signals XI and XQ are input to the multipliers 2213 and 2215. At the same time, if a spreading code index k for which spreading code to write is input to the spreading code generator 2211, the spreading code generator 2211 generates a spreading code corresponding to the spreading index index k and applies it to the multipliers 2213 and 2215. At this time, the multiplier 2213 multiplies the despread input signal dI and the spreading code to output the despread output signal dI, and the multiplier 2215 multiplies the input signal XQ with the spreading code to generate the despread output signal dQ. .

FIG. 23 illustrates a configuration of an orthogonal code despreader 321 in the structure of the QPSK receiver as shown in FIG. 3, and the structure is almost the same as that of the diffuser, and the difference is only in the adder 2325 and the adder 2323, and the operation is the same.

Referring to FIG. 23, the first spreading code generator 2311 and the second spreading code generator 2313 input a spreading code index k and generate a first spreading code and a second spreading code corresponding to the spreading code index k, respectively. . Here, the first spreading code and the second spreading code generated by the first spreading code generator 2311 and the second spreading code generator 2313 become the diffusion code of the I component and the diffusion code of the Q component, respectively. The multiplier 2315 multiplies the input quadrature spreading signal XI and the spreading code generated by the first spreading code generator 2311 to output the multiplier. The multiplier 2317 multiplies the input signal XQ by a spreading code generated by the first spreading code generator 2311 and outputs the multiplier. It can be seen that the structure of the first spreading code generator 2313 and the multipliers 2315 and 2317 is the same as the structure of the orthogonal despreader of the BPSK scheme. The multiplier 2319 multiplies the second spreading code output from the second spreading code generator 2313 and the input signal XI to output the multiplier. The multiplier 2321 multiplies the second spreading code output from the second spreading code generator 2313 and the input signal XQ and outputs the multiplier. An adder 2323 adds the output of the multiplier 2315 and the output of the multiplier 2321 to generate an orthogonal despread output signal dI. The adder 2325 subtracts the output of the multiplier 2319 from the output of the multiplier 2317 to generate an orthogonal despread output signal dQ.

24 to 27 are diagrams illustrating a despreading structure in a receiver for a method having a BPSK or QPSK structure by using a switch or adjusting power of an input signal to block or connect a Q component spread signal.

First, referring to FIG. 24, except for a configuration for selecting a BPSK path and a QPSK path according to a mode control signal transmitted as a channel assignment message transmitted from a base station, the orthogonal code despreader of the QPSK demodulation method as shown in FIG. That is, FIG. 24 is connected between a multiplier 2319 and an adder 2325 and switched between the multiplier and the mode control signal, and is connected between the multiplier 2321 and the adder 2323 and switched by the mode control signal. A switch 2413 is further provided. At this time, the switches 2411 and 2413 are controlled simultaneously.

Referring to the operation of the orthogonal code spreader as shown in FIG. 24, if the channel spreading structure is BPSK, Q is applied to the orthogonally spread XI component output from the multiplier 2319 and the XQ signal output from the multiplier 2321 by blocking the connection of the switches 2411 and 2413. The output signals after the component diffusion code is multiplied are not applied to the adder 2325 and the adder 2323. Therefore, the adders 2325 and 2323 add and subtract 0s instead of the spread signals of the Q component, respectively. Therefore, the output signals XI and XQ described later output signals output in the same structure as the BPSK structure, resulting in an orthogonal despread signal of the BPSK demodulation method.

Also, if the channel diffusion structure is QPSK, the switches 2411 and 2413 connect the multiplier 2319 and the adder 2325, respectively, and the multiplier 2321 and the adder 2323, respectively, so that the signal XI and the signal output from the multiplier 2321 are output. The output signals after the Q component spreading codes are multiplied by XQ are respectively applied to the adders 2325 and the adders 2323, respectively. Accordingly, as shown in FIG. 23, an orthogonal despread signal of the QPSK demodulation method is generated.

Secondly, referring to FIG. 25, except for a configuration for selecting a BPSK path and a QPSK path according to a mode control signal transmitted with a channel assignment message transmitted from a base station, the orthogonal code of the QPSK demodulation method as shown in FIG. Same as the despreader configuration.

Referring to the configuration of the orthogonal code spreader as shown in FIG. 25, the gain controller 2511 generates the first gain control signal in the BPSK mode and the second control in the QPSK mode according to the mode control signal transmitted with the channel assignment message transmitted from the base station. Generate a signal. A multiplier 2513 is connected between the multiplier 2319 and the adder 2325 and the gain is controlled by the gain control signal to control the output gain of the multiplier 2319. A multiplier 2515 is connected between the multiplier 2321 and the adder 2323 to control the output gain of the multiplier 2321 by the gain control signal. In this case, the gain control signals applied to the multipliers 2513 and 2515 have the same value. The first gain control signal is set to 0 to block the spreading of the Q component from being applied to the adders 2325 and the adder 2323, and the second gain control signal is set to 1 so that the spreading signal of the Q components is added to the adders 2325 and the adder 2323. It can be applied as it is.

Referring to the operation of the orthogonal despreader as shown in FIG. 25, if the channel diffusion structure is BPSK, a mode control signal indicating that the diffusion structure is BPSK is applied to the gain controller 2511. In this case, the gain controller 2511 has a first value having a zero value. The gain control signal will continue to output 0. Then, 0, which is a value for controlling the gain, is input to the multipliers 2513 and 2515 and multiplied, respectively, so that both the multipliers 2513 and 2515 output 0. Accordingly, since 0 is output from the multipliers 2513 and 2515, the adders 2325 and the adders 2323 respectively add and subtract the corresponding despread signals and zeros. Therefore, in the following output signal, by outputting a signal output in the same structure as the BPSK structure, the quadrature despread signal having the BPSK structure as shown in FIG. 22 is generated.

In addition, if the channel diffusion structure is QPSK, a mode control signal indicating that the diffusion structure is QPSK is applied to the gain controller 2411. In this case, the gain controller 2511 continuously outputs 1, which is the second gain control signal, and the gain controller Values of 1 output from 2511 are input to multipliers 2513 and 2515, respectively. Then, after the Q component despreading code is multiplied by the signal XI output from the multiplier 2319 and the signal XQ output from the multiplier 2321, respectively, the output signals are multiplied by a gain control value of 1 in the multipliers 2513 and 2515, respectively. The desired values have the same values as the output signals of the multipliers 2319 and 2321. Therefore, the output value of the multiplier 2513 is applied to the adder 2325 and the output value of the multiplier 2515 is input to the adder 2323, respectively. Accordingly, the adder 2323 adds the output of the multiplier 2315 and the output of the multiplier 2321 to output the orthogonal despread signal dI, and the adder 2325 subtracts the output of the multiplier 2319 from the output of the multiplier 2317 to output the orthogonal spread signal dQ. Accordingly, the output orthogonal spread signal is outputted with the same despread signal as the QPSK spread structure shown in FIG. 23.

Third, referring to FIG. 26, except for a configuration for selecting a BPSK path and a QPSK path according to a mode control signal transmitted with a channel assignment message transmitted from a base station, the orthogonal code of the QPSK demodulation method as shown in FIG. Same as the despreader configuration. That is, FIG. 26 is connected between the output terminal of the second spreading code generator 2313 and the multipliers 2319 and 2321. The switch 2611 is further controlled by the mode control signal to control the output of the second spreading code of the Q component. Equipped.

Referring to the operation of the orthogonal code spreader having the configuration as shown in FIG. 26, if the channel spreading structure is BPSK, the switch 2611 is switched off to generate the second spreading code of the Q components in the multipliers 2319 and 2321. The passage is blocked. Accordingly, the multiplier 2319 outputs 0 by multiplying the input signal XI by 0, and the output values of 0 are added to the adder 2325, so that the adder 2323 equals the output value of the multiplier 2317. Will print. In addition, the multiplier 2321 also outputs a value of 0 by multiplying the input signal XQ by 0, and the zero values thus output are added to the adder 2323, so that the adder outputs the same value as the output value of the multiplier 2315. . Therefore, the final output values to the operation are the same as the output values of the BPSK demodulator having the structure as shown in FIG.

When the channel diffusion structure is QPSK, the switch 2611 is connected, and the second spreading code of the Q component generated by the second spreading code generator 2313 is normally applied to the multipliers 2319 and 2321 by the connection of the switch 2611. Subsequently, the subsequent operation is the same as that of Fig. 23, and generates an orthogonal despread signal of the QPSK demodulation method.

Fourth, referring to FIG. 27, except for the configuration for selecting the BPSK path and the QPSK path according to the mode control signal transmitted with the channel assignment message transmitted from the base station, the orthogonal code of the QPSK demodulation method as shown in FIG. Same as the despreader configuration. That is, FIG. 27 is connected between a gain controller 2511 for generating a gain control signal according to a mode control signal, an output terminal of the second spreading code generator 2313 and multipliers 2319 and 2321, and the Q component by the gain control signal. And a multiplier 2711 for controlling the output of the second spreading code.

Referring to the operation of the orthogonal code despreader having the configuration as shown in FIG. 27, if the channel diffusion structure is BPSK, the gain controller 2511 generates a first gain control signal having a value of zero by the mode control signal. The multiplier 1411 multiplies the output of the second spreading code generator 2313 by 0, thereby blocking the output passage of the spreading code generator 2313 which generates the second spreading code of the Q components in the multipliers 2319 and 2321. As a result, the multiplier 2319 outputs 0 by multiplying the input signal XI by 0, and the output values of 0 are further subtracted to the adder 2325, so that the adder 2325 equals the output value of the multiplier 2317. Will print. In addition, the multiplier 2321 also outputs a value of 0 by multiplying the input signal XQ by 0, and the zero values thus output are added to the adder 2323, so that the adder outputs the same value as the output value of the multiplier 2315. . Thus, the final output values to the operation will be the same as the output values in the BPSK.

If the channel diffusion structure is QPSK, the gain controller 2511 generates a second gain control signal having a value of 1 by the QPSK mode control signal. The multiplier 2711 multiplies the output of the second spreading code generator 2313 by 1, and the multipliers 2319 and 2321 normally input the second spreading code of the Q component generated by the second spreading code generator 2313. Subsequently, the subsequent operation is the same as that of FIG. 23, and generates an orthogonal despread signal of the QPSK demodulation method.

23 to 27, the first spreading code generators 2311 and 2313 may be implemented in the same structure as that of FIG. 10. That is, the spreading code generators 2311 and 2313 each have a quasi-orthogonal code mask index table for generating a quasi-orthogonal code and a Walsh orthogonal index table for generating a Walsh orthogonal code, which are under the control of a controller not shown. Walsh orthogonal or quasi-orthogonal code. In the despreader structure of the BPSK mode, only the Walsh orthogonal code is generated as the spreading code. In the despreader structure of the QPSK mode, the controller may generate the Walsh orthogonal code or the quasi-orthogonal code as the spreading code. The diffusion code generators 2311 and 2313 are provided with tables having the structures as shown in FIGS. 15 and 16 as described above.

In addition, in the structure of the orthogonal despreading apparatus as shown in FIGS. 23 to 27, the despreading function is performed by selecting a modulation method of the BPSK mode and the QPSK mode in the modulator. That is, the orthogonal despreading apparatus of FIGS. 23 to 27 blocks the path of the diffuse code of the imaginary component output from the second spreading code generator 2313 in the BPSK mode and spreads the real component output from the first spreading code generator 2311. Only sign paths are formed. In the QPSK mode, orthogonal-spreaded input signals are despread using the spreading codes of real and imaginary components generated by the first spreading code generator 2311 and the second spreading code generator 2313.

Therefore, controlling the output of the second spreading code generator 2313 has the same effect. Therefore, when the second spreading code generator 2313 is configured with FIGS. 17 to 21, it can be seen that the orthogonal despreader has the same effect in performing the orthogonal despreading operation of the BPSK mode and the QPSK mode.

Also, in the configurations of the orthogonal despreader, in case of FIGS. 25 and 27 and 19, 20, and 21 performing the orthogonal spreading function of the QPSK mode and the BPSK modulation mode using a gain controller and a multiplier, When the mode controller (not shown) generates a mode control signal having a value of 0 in the BPSK mode and a mode control signal having a value of 1 in the QPSK mode, it is not necessary to use separate gain controllers. That is, when the mode control signal is directly applied to the corresponding multiplier, a BPSK path or a QPSK path may be formed according to the corresponding mode.

As described above, when the orthogonal spreading schemes are different from each other in the code division multiple access communication system, the orthogonal spreading modes corresponding to the orthogonal spreading units can be accommodated, and the orthogonal spreading according to the corresponding mode during the orthogonal spreading. You can choose the method. In particular, both the channels orthogonally spread in the BPSK mode in the conventional IS-95 system and the channels orthogonally spread in the QPSK mode in the next generation IMT-2000 system can be serviced. In addition, in the IMT-2000 system, both the QPSK mode and the BPSK mode channels can be serviced, and even in the case of the channel using the QPSK mode, there is an advantage in that both the spreading in the Walsh orthogonal code or the quasi-orthogonal code can be provided.

Claims (17)

A channel spreading apparatus using a plurality of different modulation modes in a transmitter of a code division multiple access communication system and sharing channels commonly required in the different plurality of modulation modes, A mode controller for generating a mode control signal and a channel spreading code index according to a modulation mode to be used and a channel to be provided through an access message from a receiving device; A spreading code generator for inputting the channel spreading code index and generating a spreading code of a real component and an imaginary spreading component corresponding to the input channel spreading index; The mode control signal is inputted, and when the input mode control signal is a BPSK modulation mode, generation of a spreading code of the imaginary component from the spreading code of the real component and the spreading code of the imaginary component from the spreading code generator is performed. Cut off circuit, And a complex multiplier for inputting a channel signal and complex multiplying the input channel signal with the spreading codes provided through the blocking circuit to spread the channel. The method of claim 1, wherein the spreading code generator, A controller for generating a quasi-orthogonal code mask index and a Walsh orthogonal code index corresponding to the designated channel spreading code index; Generating a mask of the quasi-orthogonal code of the real component corresponding to the quasi-orthogonal code mask index, generating a Walsh orthogonal code of the real component corresponding to the Walsh orthogonal code index, the quasi-orthogonal code mask of the real component and the Walsh A real-time spreading code generator for multiplying orthogonal codes to generate a channel spreading code of a real component, A mask of an imaginary orthogonal code corresponding to the quasi-orthogonal code mask index is generated, a Walsh orthogonal code of an imaginary component corresponding to the Walsh orthogonal code index is generated, and the quasi-orthogonal code mask of the imaginary component and the Walsh orthogonal code are generated. A channel spreading apparatus of a code division multiple access communication system, comprising a imaginary spreading code generator that multiplies a code to generate an imaginary spreading channel code. 3. The channel spreading apparatus of claim 2, wherein the controller does not generate the quasi-orthogonal code mask index when the controller inputs a channel spread code index that designates a Walsh orthogonal code. 3. A channel spreading apparatus according to claim 2, wherein a circuit for turning off generation of an imaginary component channel spreading code is connected to an output terminal of said imaginary component spreading code generator. 3. The code division multiple access communication system according to claim 2, wherein a circuit for turning off the generation of the imaginary component channel spreading code is located at an output terminal of the multipliers in which the imaginary channel spreading code multiplies the channel signal inside the complex multiplier. Channel diffuser. 3. A channel spreading apparatus according to claim 2, wherein a circuit for turning off the generation of the imaginary component channel spreading code is located inside the imaginary component spreading code generator. A channel despreading apparatus using a plurality of different modulation modes in a receiving apparatus of a code division multiple access communication system and sharing channels commonly required in the different plurality of modulation modes, A controller for generating a mode control signal according to a modulation mode to be used and a channel spreading code index corresponding to a channel to be used among the plurality of different modulation modes; A spreading code generator for inputting the channel spreading code index and generating a spreading code of a real component and an imaginary spreading component corresponding to the input channel spreading index; The mode control signal is input, and when the input mode control signal is a BPSK modulation mode, the generation of the spreading code of the imaginary component among the spreading code of the real component and the spreading code of the imaginary component from the spreading code generator is performed. Cut off circuit, A channel despreading apparatus of a code division multiple access communication system comprising a complex multiplier which inputs a channel signal and complex multiplies and despreads the input channel signal and the spreading codes provided through the blocking circuit. A channel transmitting apparatus of a code division multiple access communication system, Inputs a mode control signal as a selection signal, outputs the channel symbols input only when the input mode control signal is a BPSK mode control signal to one path, and transmits the input channel symbols to the one path and the other path when the QPSK mode control signal is used. A demultiplexer for outputting separately, A spreading code generator for generating a spreading code of a real component corresponding to a specified channel spreading code index and a spreading code of an imaginary component, and inputting a mode control signal and the imaginary component of the imaginary component when the input mode control signal is a BPSK modulation mode. A channel spreader comprising a circuit for turning off generation of a spreading code, a complex multiplier for inputting a channel signal, and multiplying and spreading the input channel signal and the spreading code; And a band spreader for multiplying and spreading the channel spread signal by the PEN code of real and imaginary components. A channel receiving apparatus of a code division multiple access communication system, A band despreader for inputting a channel signal transmitted from a channel transmitter, and multiplying the input signal by pien codes of real and imaginary components to despread the band; A spreading code generator for generating a spreading code of a real component corresponding to a specified channel spreading code index and a spreading code of an imaginary component, and inputting a mode control signal and the imaginary component of the imaginary component when the input mode control signal is a BPSK modulation mode. A channel despreader comprising a circuit for turning off generation of a spreading code, a complex multiplier for inputting the band despread signal, and complex multiplying the input signal and the spreading code to despread it; A code division multiple access communication system comprising a multiplexer for inputting a mode control signal as a selection signal and multiplexing and outputting the input channel symbols to the one path and the other path when the input mode control signal is a QPSK mode control signal. Channel receiver. A plurality of different modulation modes are used in a transmission apparatus of a code division multiple access communication system having a spreading code generator for generating spreading codes of real and imaginary components corresponding to a predetermined channel spreading code index. In the channel spreading method to share the channels commonly required in the modulation modes, Generating a mode control signal according to a modulation mode used in the receiving device determined as an access message from the receiving device, and generating the predetermined channel spreading code index by the channel to be used; Blocking the generation of the imaginary component spreading code when the mode control signal is a BPSK modulation mode, multiplying the channel signal to be transmitted by the spreading code of the real component; Channel spreading in a code division multiple access communication system comprising: spreading a channel signal to be transmitted when the mode control signal is a QPSK modulation mode by complex multiplying each of the spreading code of the real component and the spreading code of the imaginary component Way. A plurality of different modulation modes are used in a receiving apparatus of a code division multiple access communication system having a spreading code generator for generating spreading codes of real and imaginary components corresponding to a predetermined channel spreading code index. A channel despreading method for sharing channels commonly required in modulation modes, Generating a predetermined channel spreading code index corresponding to a mode control signal according to a modulation mode to be used and a channel to be used among the plurality of different modulation modes; Blocking the generation of the imaginary component spreading code when the mode control signal is a BPSK modulation mode, and multiplying the channel signal received through the channel to be used by the spreading code of the real component to despread the channel; In the QPSK modulation mode, the code division multiple access communication is performed by demultiplexing a channel signal received through the channel to be used by multiplying each of the real-signal spreading code and the imaginary-spreading spreading code. Channel despreading method of system. A channel transmission method in a transmission apparatus of a code division multiple access communication system having a spreading code generator for generating spreading codes of real and imaginary components, Inputs a mode control signal as a selection signal, outputs the channel symbols input only when the input mode control signal is a BPSK mode control signal to one path, and transmits the input channel symbols to the one path and the other path when the QPSK mode control signal is used. Process of outputting separately, When the BPSK mode control signal is generated, the generation of the imaginary component spreading signal is turned off, and the received channel signal is multiplied by the spreading code of the real component, and the channel signal is spread when the QPSK mode control signal is generated. Channel spreading by complex multiplication with a spreading code of a sign and an imaginary component, And multiplying the channel spread signal by a PEN code of a real component and an imaginary component to spread the spectrum. A channel receiving method in a receiving apparatus of a code division multiple access communication system having a spreading code generator for generating spreading codes of real and imaginary components, Inputting a channel signal transmitted from a transmitter, complex-multiplying the input signal by a pien code of a real component and an imaginary component; When the BPSK mode control signal is generated, the generation of the spreading code of the imaginary component is turned off, and the received channel signal is multiplied by the spreading code of the real component to despread the channel. Despreading the channel by complex multiplication with a spreading code of a spreading code and an imaginary component Receiving a code division multiple access communication system comprising inputting a mode control signal as a selection signal and multiplexing the input channel symbols to the one path and the other path when the input mode control signal is a QPSK mode control signal. Channel reception method in the device. In the channel spreading method of a code division multiple access communication system, Generating, by a receiving device, an access channel message including information on a channel spreading mode that can be serviced, and transmitting the same through an access channel; When the transmitter receives the access channel message, the transmitter determines a channel spreading mode that can be serviced by the transmitter according to the channel spreading mode of the receiver, and sends a call channel message including channel spreading information according to the determined channel spreading mode. To generate and transmit, And transmitting and assigning a dedicated channel according to the determined channel spreading mode and channel spreading information by the transmitting apparatus and the receiving apparatus. 15. The code division multiple access communication of claim 14, wherein the receiver can spread a channel using BPSK and QPSK modulation, and perform channel spreading using a BPSK or QPSK modulation according to a channel spreading scheme designated by the transmitter. Channel spreading method of the system. In the channel spreading method of a code division multiple access communication system, Generating, by the transmitting device, a call channel message including information on a channel spreading mode available for service, and transmitting the call channel message through a call channel; A receiving device determines a channel spreading mode that can be served by the receiving device according to the received channel spreading mode of the transmitting device, and includes channel spreading information according to the determined channel spreading mode according to the received channel spreading mode message; Creating a message and transmitting it through an access channel; Generating, by the transmitter, a call channel message including channel spread information according to a channel spread mode serviceable by the receiver when the access channel message is received; And transmitting and assigning a dedicated channel according to the designated channel spreading mode and channel spreading information by the transmitting apparatus and the receiving apparatus. 17. The code division multiplexing method of claim 16, wherein the transmitter is capable of spreading channels in BPSK and QPSK modulation schemes, and performs channel spreading in BPSK or QPSK modulation schemes according to channel spreading schemes that can be serviced by the receiver. Channel spreading method in a connected communication system.