KR100260445B1 - Spread signal generating apparatus in spread spectrum communication system - Google Patents

Abstract

PURPOSE: A spread signal generating apparatus in a spread spectrum communication system is provided so that it is compatible with a general system, resultant amplitude variations are reduced, and an on/off frequency of a transmission signal is lowered, by supporting first to third spread methods. CONSTITUTION: The first selecting unit(240) and the second selecting unit(250) respectively select one of I-arm spread signals and the Q-arm spread signals from the first spread unit(210), the second spread unit(220) and the third spread unit(230) according to a control signal. The first spread unit(210) receives an orthogonal code information signal, and generates I-arm spread signal and Q-arm spread signal. The second spread unit(220) receives the orthogonal code information signal, and generates I-arm spread signal and Q-arm spread signal. The third spread unit(230) receives the orthogonal code information signal, and generates I-arm spread signal and Q-arm spread signal. The generated I-arm signals are applied to input terminals of the first selecting unit(240), and the generated Q-arm signals are applied to input terminals of the second selecting unit(250), respectively. The first selecting unit(240) selects one of the I-arm spread signals according to the control signal, and outputs the selected signal through an output terminal. The second selecting unit(250) selects one of the Q-arm spread signals according to the control signal, and outputs the selected signal through the output terminal.

Description

Direct Spread Signal Generator in Spread Spectrum Communication System

The present invention relates to a spread spectrum communication system, and more particularly, to an apparatus for generating an information signal to be transmitted as a spread signal according to a direct spreading method.

Spread Spectrum Communication refers to a method of communicating with a signal having a transmission bandwidth wider than that of an information signal to be transmitted. The spread spectrum communication method is classified into a direct sequence (DS) method, a frequency hopping (FH) method, a time hopping (TH) method, and the like according to how the information signal is spread. The methods that are mainly studied are direct spreading and frequency hopping. These methods are Truncked Radio System (TRS), Code Division Multiple Access (CDMA), Digital Cellular System, Personal It can be widely applied in fields such as personal communication system (PCS) and satellite communication.

In general, a transmitter of a direct spread / code division multiple access (DS / CDMA) communication system that spreads an information signal according to direct spread and transmits the spread signal is configured as shown in FIG.

1, information signals d1 (t), d2 (t),... dN (t) is multiplied by the orthogonal codes w1 (t) to wN (t) generated by the orthogonal code generators 101 to 103, respectively, and the multipliers 111 to 113, respectively. The spreaders 141 to 143 are an I-arm pseudo noise (PN) coded by the I_PN code generator 120 and the Q_PN code generator 130 and the Q-arm PN code pQ (t). The I-arm spread signals s1I (t) to sNI (t) and the Q-arm spread signals s1Q (t) to sNQ (t) which are respectively spread by multiplying the multiplied result signals c1 (t) to cN (t) using To generate as: The I arm spread signals s1I (t) to sNI (t) thus generated are added by the adder 151 to generate the I arm combined signal xI (t), and the Q arm spread signals s1Q (t) to sNQ (t) are the adders. It is added by 152 and generated as Q-arm combined signal xQ (t). Mixer 161 is a carrier wave of the I-arm coupled signal xI (t) and in-phase components cos ωct Is mixed to output an I-arm modulated signal, and the mixer 162 is a carrier of quadrature-phase component with the Q-arm combined signal xQ (t). sin ωct Mixed to output a Q-arm modulated signal. The output I-arm modulated signal and Q-arm modulated signal are added by the adder 170 to generate the transmission signal s (t). The generated transmission signal s (t) is processed through band pass filtering and power amplification and then radiated into the air through an antenna (not shown).

Diffusers 141 to 143 in FIG. 1 are implemented as multipliers 2 and 4, as shown in FIG. In this case, the multiplier 2 multiplies the orthogonal coded information signal c (t) output after being multiplied by the multipliers 111 to 113 of the previous step and the I-arm PN code pI (t) generated by the I_PN code generator 120 to spread the I-arm. Generate the signal sI (t). The multiplier 4 multiplies the orthogonal resultant signal c (t) output after being multiplied by the multipliers 111 to 113 in the previous step and the Q arm PN code pQ (t) generated by the Q_PN code generator 130 to spread the Q arm. Generate the signal sQ (t).

As shown in FIG. 2, a method of generating a spread signal by multiplying an I-arm PN code and a Q-arm PN code by an orthogonal coded I-arm information signal and a Q-arm information signal, respectively, is described in US Patent No. 5,416,797 entitled "System and Method for Generating Signal Waveforms in a CDMA Celluar Telephone System. However, this spreading signal generation method uses the I-arm PN code and the Q-arm PN code as they are without any modification (multiply the I-arm PN code and the Q-arm PN code by the I-arm orthogonal code information signal and the Q-arm orthogonal code information signal). In order to spread the information signal, the amplitude variation of the I-arm combined signal and the Q-arm combined signal, and consequently the transmission signal s (t), is increased, and the frequency at which the information signal is turned on / off increases. . This phenomenon requires a high linearity characteristic of the power amplifier when amplifying a transmission signal at the transmitter, and makes it difficult to recover the clock and the signal at the receiver.

As a technique for solving such a problem, there is a Korean Patent No. 128918 entitled "Data Transmitter and Receiver in a Spread Spectrum Communication System Using a Pilot Channel", which was filed and filed by the present applicant on November 22, 1994. . This patent No. 128918 was filed with the U.S. Patent and Trademark Office on November 22, 1995, and was granted patentability on January 27, 1998 as patent number 5,712,869. Another technique is Korean Patent Application No. 95-42989 entitled "Direct Diffusion / Code Division Multiple Access Communication System Using Pilot Channel" filed on November 22, 1995 by the applicant of the present application.

On the other hand, in generating a spread signal of a spread spectrum communication system, each device disclosed in the aforementioned patents is fixed in any one structure, which is not suitable for a system requiring various spreading structures. For example, in implementing a DS / CDMA communication system, a spreading signal generation scheme may vary depending on which region (country) the system is installed in. In addition, the system manufacturer needs to satisfy the requirements of the spreading signal generation method required in each region rather than implementing each system according to the region in which the system is installed. In other words, it is desirable that the DS / CDMA communication system be designed to support various spreading signal generation methods.

In addition, if a system other than the one adopting a certain signal generation method is implemented, the system needs to be compatible with the existing system for the time being. Therefore, in this case, it would be desirable for the newly implemented system to be designed to be compatible with the existing system.

Accordingly, an object of the present invention is to provide an apparatus for generating spread signals according to direct spread in various ways in a spread spectrum communication system.

Another object of the present invention is to provide an apparatus for ensuring compatibility between a conventional signal generation method and a new signal generation method newly implemented in a spread spectrum communication system.

It is another object of the present invention to provide a transmitter for generating a spread signal according to various spreading schemes in a spread spectrum communication system and converting the spread signal into a transmission signal.

Diffusion apparatus according to the present invention for achieving these objects comprises a first diffusion unit, a second diffusion unit, and a third diffusion unit, each of the first diffusion method, the second diffusion method, and the third Support diffusion methods. The first spreader multiplies the encoded information signal by an I arm PN code and a Q arm PN code, respectively, to generate an I arm spread signal and a Q arm spread signal. The second spreader inverts one of the Q-arm PN code and the I-arm PN code, multiplies the encoded information signal by the Q-arm PN code or the inverted Q-arm PN code to generate an I-arm spread signal, and encodes the coded information signal. The Q-arm spread signal is generated by multiplying the information signal by the I-arm PN code or the inverted I-arm PN code. The third spreader is configured to include a first spreader and a second spreader for inputting an encoded information signal, and adds spread signals generated by the spreaders to generate an I-arm spread signal and a Q-arm spread signal. . The diffusion apparatus according to the present invention further includes a selection unit for selectively outputting the I-arm spread signal and the Q-arm spread signal generated by the first spreader, the second spreader, or the third spreader according to the spreading method determination signal applied. It is made to include.

The diffusion device according to the present invention ensures compatibility with the existing system through the first diffusion unit, and alternately arrange the first diffusion unit and the second diffusion unit alternately for each channel, or the first diffusion unit, the second diffusion unit, and the third diffusion unit. By distributing the diffusion unit, the amplitude variation degree and the on / off frequency of the transmission signal can be reduced.

1 is a diagram illustrating a transmitter configuration of a general direct spread / code division multiple access communication system (DS / CDMA) to which the present invention is applied.

2 is a view showing the configuration of a diffuser according to the prior art shown in FIG.

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

4 is a view showing the configuration of a cross-control diffuser according to the present invention shown in FIG.

5 is a view illustrating a configuration of a first diffusion unit illustrated in FIG. 4.

6A and 6B are views illustrating a configuration of the second diffusion unit illustrated in FIG. 4.

FIG. 7 is a view showing a modified example of the second diffusion unit shown in FIGS. 6A and 6B.

8 is a view illustrating a configuration of a third diffusion unit illustrated in FIG. 4.

9 is a diagram showing that the cross-control diffuser according to the present invention can be selectively determined by the spread method decision signal.

10 is a view showing the configuration of a diffuser according to a first embodiment of the present invention.

11 is a view showing the configuration of a diffuser according to a second embodiment of the present invention.

12 is a view showing the configuration of a diffuser according to a third embodiment of the present invention.

13 is a view showing the configuration of a diffuser according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or chip designer, and the definitions should be made based on the contents throughout the present specification.

3 is a diagram illustrating a configuration of a transmitter of a DS / CDMA communication system according to the present invention. Unlike the spreaders 141 to 143 shown in FIG. 1, the transmitter is a cross control diffuser 201 controlled by control signals CCQS1 to CCQSN, respectively. It comprises -203. The control signals CCQS1 to CCQSN are signals for determining the generation method of the spread signal by the spreaders 201 to 203. The cross-control spreaders 201 to 203 convert the orthogonal encoding information signal into the I-arm spread signal and the Q-arm spread signal by using the I-arm PN code and the Q-arm PN code according to the first spreading scheme of the structure shown in FIG. When generating, the I-arm PN code may be used to generate the I-arm spread signal and the Q-arm PN code may be used to generate the Q-arm spread signal as in the conventional method.

In addition, the cross-control spreaders 201 to 203 use the I-arm PN code and the Q-arm PN code as the I-arm spread signal and the Q-arm PN code according to the second spreading scheme having the structure shown in FIGS. 6A and 6B. When generated as a cancer spreading signal, the I-arm PN code and the Q-arm PN code are supplied in an intersecting form. That is, the cross-control spreaders 201 to 203 may use a Q-arm PN code to generate an I-arm spread signal, and use an I-arm PN code to generate a Q-arm spread signal. At this time, the sign of any one of the I-arm PN code and the Q-arm PN code is reversed and supplied.

In addition, the cross-control spreaders 201 to 203 may generate an I-arm spread signal and a Q-arm spread signal according to the third spreading scheme having the structure shown in FIG. 8. The third diffusion method has a structure in which both the first diffusion method and the second diffusion method are used. The third diffusion method generates an I-arm spread signal and a Q-arm spread signal generated in accordance with the second diffusion method, respectively. The added result is added to the I arm spread signal and the Q arm spread signal to generate the added result as an I arm spread signal and a Q arm spread signal, respectively.

As such, the cross control diffusers 201 to 203 are structured to support the first diffusion method, the second diffusion method, or the third method. The cross control diffusers 201 to 203 may have a structure of a first diffusion method, which maintains compatibility with the existing diffusers as shown in FIG. 1. When the cross-control spreaders 201 to 203 use the second spreading method together with the first spreading method, the amplitude variation of the transmission signal can be alleviated and the frequency of on / off of the transmission signal can be reduced. The third spreading method accommodates the first spreading method and the second spreading method in one channel, and this structure can alleviate the amplitude variation of the transmission signal and reduce the on / off frequency of the transmission signal.

Referring to FIG. 3, the first information signal d1 (t) to be transmitted is multiplied by the first orthogonal code w1 (t) generated by the first orthogonal code generator 101 and the multiplier 111 and then the first orthogonal coded information signal c1. generated by (t) The first cross-control spreader 201 uses the I-arm PN code pI (t) generated by the I_PN code generator 120 and the Q-arm PN code pQ (t) generated by the Q_PN code generator 130 to generate the first orthogonal encoding information signal c1. (t) is generated as the first I arm spread signal s1I (t) and the first Q arm spread signal s1Q (t). The second information signal d2 (t) to be transmitted is multiplied by the second orthogonal code w2 (t) generated by the second orthogonal code generator 102 and the multiplier 112 and then generated as the second orthogonal coded information signal c2 (t). . The second cross-control spreader 202 uses the I-arm PN code pI (t) generated by the I_PN code generator 120 and the Q-arm PN code pQ (t) generated by the Q_PN code generator 130 to generate the second orthogonal encoding information signal c2. (t) is generated as the second I arm spread signal s2I (t) and the second Q arm spread signal s2Q (t). In the same way, the Nth information signal dN (t) is multiplied by the Nth orthogonal code wN (t) generated by the Nth orthogonal code generator 103 and the multiplier 113 and then generated as the Nth orthogonal coded information signal cN (t). . The Nth crossover control spreader 203 uses the N-arm PN code pI (t) generated by the I_PN code generator 120 and the Q-arm PN code pQ (t) generated by the Q_PN code generator 130 to generate the Nth orthogonal encoding information signal cN. (t) is generated as the NI-arm spread signal sNI (t) and the N-Q arm spread signal sNQ (t).

The generated I arm spread signals s1I (t) to sNI (t) are added by the adder 151 to generate the I arm combined signal xI (t), and the Q arm spread signals s1Q (t) to sNQ (t). Is added by adder 152 to generate as Q-arm combined signal xQ (t). The I-arm combined signal xI (t) is a carrier of in phase component by the mixer 161. cos ωct Mixed with and generated as an I-arm modulated signal, and the Q-arm combined signal xQ (t) is a carrier of quadrature phase component by mixer 162. sin ωct Mixed with and generated as a Q-arm modulated signal. The I-arm modulated signal and the Q-arm modulated signal output from the mixers 161 and 162 are added by the adder 170 and then generated as the transmission signal s (t). This transmission signal s (t) is bandpass filtered by a band pass filter (not shown), and amplified by a power amplifier (not shown), and then an antenna (not shown). It is radiated into the air through).

The orthogonal code generators 101 to 103 may be implemented as Walsh code generators. The cross control spreaders 201 to 203 are controlled by the control signals CCQS1 to CCQSN, which are spreading type determination signals, as shown in FIG. 4 to generate spreading signals in accordance with the corresponding scheme.

Referring to FIG. 4, as described above, the cross control diffusers 201 to 203 may include a first diffusion unit 210 supporting the first diffusion method, a second diffusion unit 220 supporting the second diffusion method, and a first diffusion method. And a third diffusion unit 230 that supports the third diffusion method according to the combination of the second diffusion methods, and further includes a first selector 240 and a second selector 250. The first selector 240 and the second selector 250 may include the I-arm spread signal and the Q-arm spread signal generated by the first spreader 210, the second spreader 220, and the third spreader 230 according to the control signal CCQS. Selects and outputs either the I-arm spread signal and the Q-arm spread signal of?

The first spreader 210 inputs an orthogonal encoding information signal c (t), and uses the input orthogonal encoding information signal c (t) using the I-arm PN code pI (t) and the Q-arm PN code pQ (t). It is generated by the I arm spread signal saI (t) and the Q arm spread signal saQ (t). The second spreader 220 inputs the orthogonal encoding information signal c (t), and uses the input orthogonal encoding information signal c (t) using the I-arm PN code pI (t) and the Q-arm PN code pQ (t). It is generated by the I arm spread signal sbI (t) and the Q arm spread signal sbQ (t). The third spreader 230 inputs the orthogonal encoding information signal c (t), and uses the input orthogonal encoding information signal c (t) using the I-arm PN code pI (t) and the Q-arm PN code pQ (t). It is generated by the I arm spread signal scI (t) and the Q arm spread signal scQ (t). The generated I arm spread signals saI (t), sbI (t), and scI (t) are applied to the signal input terminals A, B, and C of the first selector 240, respectively. The generated Q-arm spread signal is applied to the signal input terminals A, B, and C of the second selector 250, saQ (t), sbQ (t), and scQ (t), respectively. The first selector 240 selects any one of the I arm spread signals saI (t), sbI (t), and scI (t) in response to the control signal CCQS applied to the selection signal input terminal SEL to output the output terminal ( OUT is outputted as an I arm spread signal sI (t). The second selector 250 selects one of the Q-arm spread signals saQ (t), sbQ (t), and scQ (t) in response to the control signal CCQS applied to the selection signal input terminal SEL to output the output terminal ( OUT is output as the Q-arm spread signal sQ (t).

The first diffusion unit 210, the second diffusion unit 220, and the third diffusion unit 230 may be implemented as shown in FIGS. 5, 6A (or 6B) and 8, respectively.

Referring to FIG. 5, the first spreader 210 includes multipliers 211 and 212. The multiplier 211 multiplies the orthogonal encoding information signal c (t) by the I-arm PN code pI (t) to generate the I-arm spread signal saI (t). The multiplier 212 multiplies the orthogonal encoding information signal c (t) by the Q-arm PN code pQ (t) to generate a Q-arm spread signal saQ (t). As described above, the first spreader 210 generates an I-arm spread signal using the I-arm PN code pI (t), and generates a Q-arm spread signal using the Q-arm PN code pQ (t). That is, in the spread signal generation operation by the first spreader 210, the I-arm PN code pI (t) is directly applied to the I-arm, and the Q-arm PN code pQ (t) is directly applied to the Q-arm. Operation of the first diffusion unit 210 is represented by Equation 1 below.

saI (t) = c (t) pI (t)

saQ (t) = c (t) pQ (t)

Referring to FIG. 6A, the second spreader 220 includes multipliers 211, 212, and 213. The multiplier 211 multiplies the orthogonal encoding information signal c (t) by the Q-inverted Q-arm PN code to generate an I-arm spread signal sbI (t). The multiplier 212 multiplies the orthogonal encoding information signal c (t) by the I-arm PN code pI (t) to generate the Q-arm spread signal sbQ (t). The multiplier 213 multiplies the Q-arm PN code pQ (t) by the value of "-1" to generate a Q-inverted Q-arm PN code. As such, the second spreader 220 generates an I-arm spread signal using the Q-inverted Q-arm PN code, and generates a Q-arm spread signal using the I-arm PN code pI (t). That is, in the spread signal generation operation by the second spreader 220, the Q-arm PN code whose sign is inverted is applied to the I-arm, and the I-arm PN code pI (t) is applied to the Q-arm. The operation of the second diffusion unit 220 is represented by Equation 2 below.

sbI (t) =-c (t) pQ (t)

sbQ (t) = c (t) pI (t)

The second spreader 220 for generating the I-arm spread signal and the Q-arm spread signal represented by Equation 2 may be configured as shown in FIG. 6B.

Referring to FIG. 6B, the second spreader 220 includes multipliers 211, 212, and 214. The multiplier 211 multiplies the orthogonal encoding information signal c (t) by the Q-arm PN code pQ (t) to generate the I-arm spread signal sbI (t). Multiplier 212 multiplies the orthogonal encoding information signal c (t) by the inverted I-arm PN code to generate the Q-arm spread signal sbQ (t). Multiplier 214 multiplies the value of I arm PN code pI (t) by the value of "-1" to generate an I-arm PN code inverted. As described above, the second spreader 220 generates the Q-arm spread signal using the sign-inverted I-arm PN code, and generates the I-arm spread signal using the Q-arm PN code pQ (t). That is, in the spread signal generation operation by the second spreader 220, the Q-arm PN code is applied to the I-arm and the inverted I-arm PN code is applied to the I-arm. Operation of the second diffusion unit 220 is represented by Equation 3 below.

sbI (t) = c (t) pQ (t)

sbQ (t) =-c (t) pI (t)

The second diffusion unit 220 may be structured as shown in FIG. 6A to generate a spread signal having the form as shown in Equation 2, or to generate the spread signal having the form as shown in Equation 3. It may be structured as shown in FIG. 6B. At this time, the diffusion part of the structure shown in FIG. 6a and the diffusion part of the structure shown in FIG. 6b generate different types of diffusion signals as shown in Equation 2 and Equation 3, respectively. However, it should be noted that they have the same effect. Here, the effect obtained by the second diffusion unit 220 means that some channels of the N channels use the first diffusion method and some channels of the N channels at a predetermined ratio compared to the case where all N channels use the first diffusion unit 210. With the structure using the second diffusion method, it is possible to mitigate the amplitude variation of the transmission signal and to prevent the frequency of the transmission signal on / off. The fact that the second diffusion unit 220 is configured as shown in FIG. 6A or as shown in FIG. 6B has the same effect will be apparent from the following description.

7 is a view illustrating various modifications of the second diffusion unit 220 having the configuration as shown in FIGS. 6A and 6B. In the case of the second diffusion unit 220 illustrated in FIG. 6A, an operation of inverting the Q-arm PN code pQ (t) by multiplying the value of "-1" by the Q-arm PN code pQ (t) is performed by the inverter 221. . In the case of the second diffusion unit 220 illustrated in FIG. 6B, an operation of inverting the I-arm PN code pI (t) by multiplying the value of “I” by the I-arm PN code pI (t) is performed by the inverter 222. . The operation of inverting the Q-arm PN code pQ (t) may be performed in the case of using the inverters 223 and 225 instead of the inverter 221. This is because even if the operation of inverting the Q-arm PN code pQ (t) is performed by any one of the inverters 221, 223, and 225, the resulting spread signal has the form as shown in Equation 2 above. The operation of inverting the I-arm PN code pI (t) may be performed in the same manner when the inverters 224 and 226 are used instead of the inverter 222. This is because even if the operation of inverting the I-arm PN code pI (t) is performed by any one of the inverters 222, 224, 226, the resulting spread signal has the form as shown in Equation 3 above.

Referring to FIG. 8, the third spreader 230 includes a first diffuser 210, a second diffuser 220, and adders 231 and 232. That is, the third diffusion unit 230 has a structure in which the first diffusion unit 210 and the second diffusion unit 220 are the same, and is a combination of a diffusion method by the first diffusion unit 210 and a diffusion method by the second diffusion unit 220. The third diffusion unit 230 is configured according to the combination of the first diffusion unit 210 and the second diffusion unit 220 to mitigate the amplitude variation of the transmission signal and to turn on / off the transmission signal as compared with the case where only the first diffusion unit 210 is used. It is to prevent the frequency.

In FIG. 8, the orthogonal encoding information signal c (t), which is an input signal, is input to the x-arm and y-arm to form the x-arm orthogonal encoding information signal cx (t) and the y-arm orthogonal encoding information signal cy (t). In x-arm, the first spreader 210 spreads the orthogonal coded information signal cx (t) according to the first spreading method by using the I-arm PN code pI (t) and the Q-arm PN code pQ (t). The I arm spread signal sxI (t) and the Q arm spread signal sxQ (t) are output. In y-arm, the second spreader 220 spreads the orthogonal coded information signal cy (t) according to the second spreading method by using the I-arm PN code pI (t) and the Q-arm PN code pQ (t). The I arm spread signal sxI (t) and the Q arm spread signal sxQ (t) are output. The I arm spread signal sxI (t) in the x-arm and the I arm spread signal syI (t) in the y-arm are added by the adder 231 and then generated as the I arm spread signal scI (t). The Q arm spread signal sxQ (t) in the x-arm and the Q arm spread signal syQ (t) in the y-arm are added by the adder 232 and then generated as the Q arm spread signal scQ (t). That is, the adder 231 combines the I-arm spread signals from the spread signals generated by the first spreader 210 and the second spreader 220 to generate an I-arm spread signal scI (t) according to the third spreading method. 232 combines the Q-arm spread signals from the spread signals generated by the first spreader 210 and the second spreader 220 to generate a Q-arm spread signal scQ (t) according to the third spreading method.

In FIG. 8, the adders 231 and 232 are included in the third spreader 230, but the adders 231 and 232 may be connected to the outside of the third spreader 230 to perform the same function. In addition, the first diffusion unit 210 configured in the third diffusion unit 230 has the same structure as shown in FIG. 5, and the second diffusion unit 220 has the same structure as shown in FIG. 6A or 6B. If the third diffusion unit 230 is implemented as a structure including the first diffusion unit 210 having the structure shown in FIG. 5 and the second diffusion unit 220 shown in FIG. 6A, the diffusion operation by the third diffusion unit 230 is as follows. Equation (4). If the third diffusion unit 230 is implemented as a structure including the first diffusion unit 210 having the structure shown in FIG. 5 and the second diffusion unit 220 shown in FIG. 6B, the diffusion operation by the third diffusion unit 230 is as follows. Equation 5

scI (t) = sxI (t) + syI (t)

= cx (t) pI (t)-cy (t) pQ (t) = c (t) · [pI (t)-pQ (t)]

scQ (t) = sxQ (t) + syQ (t)

= cx (t) pQ (t) + cy (t) pI (t) = c (t) · [pI (t) + pQ (t)]

scI (t) = sxI (t) + syI (t)

= cx (t) pI (t) + cy (t) pQ (t) = c (t) · [pI (t) + pQ (t)]

scQ (t) = sxQ (t) + syQ (t)

= cx (t) pQ (t)-cy (t) pI (t) = c (t) · [pQ (t)-pI (t)]

3, each of the cross control spreaders 201 to 203 of the N channels is structured as shown in Figs. 5, 6A (or 6B) or 8 according to the spreading mode determination signals CCQS1 to CCQSN. For example, if " CCQS1 = 1 (01) ", the cross control diffuser 201 is constructed in a first spreading manner as shown in FIG. 5, and if " CCQS1 = 2 (10) ", the cross control diffuser 201 is shown in FIG. 6A (or FIG. 6B). As shown in FIG. 2, the cross-control diffuser 201 may be configured to have a third spreading scheme as shown in FIG. 8 when "CCQS1 = 3 (11)". If the spreading mode decision signals CCQS1 to CCQSN of N channels are all the same value, the cross control spreaders 201 to 203 will all have the same spreading structure. The diffusers 201-203 will have different diffusion structures.

If the spreading mode determination signals CCQS1 to CCQSN are all set to a value of "1", the spreader of FIG. 3 will be the same as the spreader structure of the conventional DS / CDMA communication system shown in FIG. Since the spreader having such a structure increases the amplitude of the transmission signal or increases the on / off frequency of the signal, it is preferable to use the diffuser only when maintaining compatibility with the existing system.

Therefore, in the present invention, instead of the values of the spreading mode determination signals CCQS1 to CCQSN all being "1", the values are appropriately "1", "2" or "3". By doing so, it is possible to mitigate the amplitude variation of the transmission signal and to reduce the frequency of the transmission signal on / off while ensuring compatibility with the existing system. For the operation of the present invention, each of the plurality of spreaders receives the spread method decision signals CCQS1 to CCQSN as shown in FIG. 9, and performs the spread operation according to the spread structure determined by the input spread method decision signals CCQS1 to CCQSN. It will be implemented as a cross-control diffuser.

10 to 13 is a view showing an embodiment of the operation according to the present invention, that is, the spreader structure to reduce the amplitude of the transmission signal on / off and to reduce the amplitude variation of the transmission signal while ensuring compatibility with the existing system.

Referring to FIG. 10, the spreader according to the first embodiment of the present invention generates a first signal as a first spreading signal according to a first spreading method, and converts a second signal into a second spreading signal according to a second spreading method. Generate a third signal as a third spreading signal according to the first spreading method, generate a fourth signal as a fourth spreading signal according to the second spreading method,. … The N th signal is generated as the N th spread signal according to the second spreading method. That is, the spreader according to the first embodiment of the present invention has a structure in which the first diffusion method and the second diffusion method are alternately arranged for each channel.

Referring to FIG. 11, a spreader according to a second embodiment of the present invention generates a first signal as a first spreading signal according to a first spreading method, and converts a second signal into a second spreading signal according to a second spreading method. Generate a third signal as a third spreading signal according to a third spreading method, generate a fourth signal as a fourth spreading signal according to a first spreading method, and generate a fifth signal according to the second spreading method. Generating a fifth spreading signal and generating a sixth spreading signal according to the third spreading method; … The N th signal is generated as the N th spread signal according to the third spreading method. That is, the spreader according to the second embodiment of the present invention has a structure in which the first diffusion method, the second diffusion method, and the third diffusion method are alternately arranged for each channel.

Referring to FIG. 12, a spreader according to a third embodiment of the present invention generates a first signal as a first spreading signal according to a first spreading method, and converts a second signal into a second spreading signal according to a first spreading method. Generate a third signal as a third spreading signal according to the first spreading method, generate a fourth signal as a fourth spreading signal according to the second spreading method, and generate a fifth signal according to the second spreading method. Generating a fifth spreading signal, and generating a sixth spreading signal as a sixth spreading signal according to the second spreading method; … The N th signal is generated as the N th spread signal according to the second spreading method. That is, the spreader according to the third embodiment of the present invention has a structure in which the first diffusion method and the second diffusion method are alternately arranged several times for each channel.

Referring to FIG. 13, a spreader according to a fourth embodiment of the present invention generates a first signal as a first spreading signal according to a first spreading method, and converts a second signal into a second spreading signal according to a second spreading method. Generate a third signal as a third spreading signal according to the first spreading method, generate a fourth signal as a fourth spreading signal according to the second spreading method, and generate a fifth signal according to the first spreading method. Generating a fifth spreading signal, and generating a sixth spreading signal as a sixth spreading signal according to the second spreading method; … The N th signal is generated as the N th spread signal according to the third spreading method. That is, the spreader according to the fourth embodiment of the present invention has a structure in which the first diffusion method and the second diffusion method are alternately arranged for each channel, and an arbitrary channel is arranged in the third diffusion method.

10 to 13, the spreader according to the embodiment of the present invention, instead of being structured according to any one method, at least a first diffusion unit supporting the first diffusion method and a second diffusion method supporting the second diffusion method And a third diffusion unit supporting the first diffusion unit, the second diffusion unit, and the third diffusion method. In this case, the first diffusion unit, the second diffusion unit, and the third diffusion unit are configured to be alternately arranged for each channel or alternately arranged for several channels. As described above, the spreader configured to have such a structure includes a first spreader to ensure compatibility with an existing system, while reducing the amplitude variation of the transmission signal by connecting the first spreader and the second spreader to each other. It is to reduce the on / off frequency of the transmission signal.

Now, assuming that the diffuser according to the present invention is implemented as shown in FIG. 10, the structure of the cross control diffuser 201 of FIG. 3 supports the first spreading scheme and the cross control spreader 202 supports the second spreading scheme. Will be. At this time, the cross control spreader 201 inputs the first channel orthogonal coding information signal c1 (t) and then uses the input I channel PN code pI (t) and the Q arm PN code pQ (t) to input the first channel orthogonal coding information. The signal c1 (t) is spread to generate a first channel I arm spread signal s1I (t) and a first channel Q arm spread signal s1Q (t). The cross control spreader 202 inputs the second channel orthogonal encoding information signal c2 (t) and then uses the input I channel PN code pI (t) and the Q arm PN code pQ (t) to input the second channel orthogonal encoding information signal. c2 (t) is diffused to generate a second channel I arm spread signal s2I (t) and a second channel Q arm spread signal s2Q (t). The adder 151 adds the first channel I arm spread signal s1I (t) and the second channel I arm spread signal s2I (t) to generate the I arm combined signal xI (t), and the adder 152 adds the first channel Q arm spread. The signal s1Q (t) and the second channel Q-arm spread signal s2Q (t) are added to generate a Q-arm combined signal xI (t). The mixer 161 mixes the I-arm combined signal xI (t) and the carrier cosωct of the in-phase component to output the I-arm modulated signal, and the mixer 162 mixes the Q-arm combined signal xQ (t) and the carrier sinωct of the quadrature component to Q-arm. Output the modulated signal. The I-arm modulated signal and the Q-arm modulated signal output from the mixers 161 and 162 are added by the adder 170 and then generated as the transmission signal s (t). In this case, the amplitude variation of the transmission signal s (t) is alleviated, which means that the amplitude variation of the I arm combined signal xI (t) and the Q arm combined signal xQ (t) is alleviated. Reducing means that the I-arm combined signal x1I (t) and the Q-arm combined signal xQ (t) do not become zero at the same time. This effect will be clearly seen from Table 1 below.

c1 (t) c2 (t) pI (t) pQ (t) xI1 (t) xQ1 (t) xI2 (t) xQ2 (t) xI3 (t) xQ3 (t) 0 0 0 0 2 2 0 2 2 0 0 0 0 One 2 -2 2 0 0 -2 0 0 One 0 -2 2 -2 0 0 2 0 0 One One -2 -2 0 -2 -2 0 0 One 0 0 0 0 2 0 0 2 0 One 0 One 0 0 0 -2 2 0 0 One One 0 0 0 0 2 -2 0 0 One One One 0 0 -2 0 0 -2 One 0 0 0 0 0 -2 0 0 -2 One 0 0 One 0 0 0 2 -2 0 One 0 One 0 0 0 0 -2 2 0 One 0 One One 0 0 2 0 0 2 One One 0 0 -2 -2 0 -2 -2 0 One One 0 One -2 2 -2 0 0 2 One One One 0 2 -2 2 0 0 -2 One One One One 2 2 0 2 2 0

In Table 1, c1 (t) and c2 (t) are a first channel orthogonal encoding information signal and a second channel orthogonal encoding information signal, pI (t) is an I-arm PN code, and pQ (t) is Q-arm PN code. The xI1 (t) and xQ1 (t) are the I-arm combined signal and the Q-arm combined signal generated when the cross-control diffusers 201 and 202 of FIG. 3 are all structured according to the first diffusion method. The xI2 (t), xQ2 (t), xI3 (t), and xQ3 (t) are structured according to the first diffusion scheme of the cross control diffuser 201 of FIG. 3, and the cross control diffuser 202 is shown in FIGS. 6A and 6B. The I-arm combined signal and the Q-arm combined signal generated in the structure according to the second diffusion method as described above. Among them, xI2 (t) and xQ2 (t) are the I-arm combined signal and the Q-arm combined signal generated when the cross-control diffuser 202 is structured according to the second diffusion scheme as shown in FIG. 6A. That is, the cross-control spreader 202 generates an I-arm spread signal and a Q-arm spread signal by using an inverted Q-arm PN code applied to the I-arm and an I-arm PN code applied to the Q-arm when generating an orthogonal coded information signal as a spread signal. Create In contrast, xI3 (t) and xQ3 (t) are the I-arm combined signal and the Q-arm combined signal generated when the cross-control diffuser 202 is constructed according to the second diffusion method as shown in FIG. 6B. That is, the cross-control spreader 202 generates the I-arm spread signal and the Q-arm spread signal by using the Q-arm PN code applied to the I-arm and the inverted I-arm PN code applied to the Q-arm when generating the orthogonal coded information signal as the spread signal. Create The combined signals obtained in Table 1 are constructed when the channel is 2, that is, when the orthogonal encoding information signals c1 (t) and c2 (t) are applied. The combined signals of the I arm spread signal and the Q arm spread signals generated by the cross-control spreader 202 structured according to the spread method are taken as an example.

The final I-arm combined signal xI1 (t) and Q-arm combined signal xQ1 (t) generated by the cross control diffusers 201 and 202 structured according to the first diffusion scheme are represented by Equation 6 below. In calculating the values of the I-arm combined signal and the Q-arm combined signal, a value represented by "0" represents a value of "+1" and a value represented by "1" represents a value of "-1".

xI1 (t) = s1I (t) + s2I (t) = c1 (t) pI (t) + c2 (t) pI (t)

xQ1 (t) = s1Q (t) + s2Q (t) = c1 (t) pQ (t) + c2 (t) pQ (t)

The final I arm combined signal xI2 (t) and Q arm generated by the cross control diffuser 201 structured according to the first spreading method and the cross control diffuser 202 structured according to the second spreading method as shown in FIG. 6A. The combined signal xQ2 (t) is represented by Equation 7 below. In calculating the values of the I-arm combined signal and the Q-arm combined signal, a value represented by "0" represents a value of "+1" and a value represented by "1" represents a value of "-1".

xI2 (t) = s1I (t) + s2I (t) = c1 (t) pI (t)-c2 (t) pQ (t)

xQ2 (t) = s1Q (t) + s2Q (t) = c1 (t) pQ (t) + c2 (t) pI (t)

I-arm combined signal xI3 (t) and Q-arm combined signal generated by the cross control diffuser 201 structured according to the first spreading method and the cross control diffuser 202 structured according to the second spreading method as shown in FIG. 6B. xQ3 (t) is shown in Equation 8 below. In calculating the values of the I-arm combined signal and the Q-arm combined signal, a value represented by "0" represents a value of "+1" and a value represented by "1" represents a value of "-1".

xI3 (t) = s1I (t) + s2I (t) = c1 (t) pI (t) + c2 (t) pQ (t)

xQ3 (t) = s1Q (t) + s2Q (t) = c1 (t) pQ (t)-c2 (t) pI (t)

When the I-arm combined signal and the Q-arm combined signal represented by Equations 6 to 8 are obtained, the magnitude value and power of the transmission signal s (t) finally generated by the adder 170 of FIG. The values are shown in Table 2 below.

xI1 (t) xQ1 (t) Vrms1 Power 1 xI2 (t) xQ2 (t) xI3 (t) xQ3 (t) Vrms2 Power2 2 2 8 0 2 2 0 2 2 -2 8 2 0 0 -2 2 -2 2 8 -2 0 0 2 2 -2 -2 8 0 -2 -2 0 2 0 0 0 0 2 0 0 2 2 0 0 0 0 0 -2 2 0 2 0 0 0 0 0 2 -2 0 2 0 0 0 0 -2 0 0 -2 2 0 0 0 0 -2 0 0 -2 2 0 0 0 0 0 2 -2 0 2 0 0 0 0 0 -2 2 0 2 0 0 0 0 2 0 0 2 2 -2 -2 8 0 -2 -2 0 2 -2 2 8 -2 0 0 2 2 2 -2 8 2 0 0 -2 2 2 2 8 0 2 2 0 2

In Table 2, Vrms1 and power1 represent Vrms values and power values of the transmission signal generated when the cross-control diffusers 201 and 202 of FIG. 3 are all structured according to the first spreading scheme. In contrast, Vrms2 and power2 represent the Vrms value and the power value of the transmission signal generated when the cross-control diffuser 201 of FIG. 3 is constructed according to the first spreading scheme and the cross-control spreader 202 is constructed according to the second spreading scheme. . It can be seen that the Vrms value and the power value of the transmission signal generated when the cross control diffusers 201 and 202 are all structured in the first spreading method have a large amplitude variation and a large on / off frequency. At this time, the power value of the transmission signal has a large amplitude variation such as "8" and "0", and the power value of the transmission signal is turned on / off as 8 → 0, 0 → 8.

On the contrary, the Vrms value of the transmission signal generated when the cross-control diffuser 201 of FIG. 3 is constructed in the first diffusion scheme and the cross-control diffuser 202 is constructed in the second diffusion scheme as shown in FIG. 6A or 6B and The power value is a constant value (" "," 2 "), and there is no phenomenon of turning on / off.

Therefore, when structuring the spreader according to the present invention in the form as shown in Figs. 10 to 13, it is possible to prevent the amplitude variation and the on / off frequency of the transmission signal caused by the conventional spreader structure as shown in Fig. Will be. In other words, the spreader according to the present invention is structured in one of the diffusion methods by alternately structuring the first diffusion method and the second diffusion method for each channel or alternately structuring the first diffusion method, the second diffusion method, and the third diffusion method for each channel. There is an effect of eliminating the problems caused when using a diffuser. It should be noted that this effect can be obtained equally even when structuring the diffuser in any of the forms shown in FIGS. 10 to 13 as described above.

As described above, the present invention spreads the information signal for each channel in various spreading methods such as the first spreading method, the second spreading method, and the third spreading method in the DS / CDMA communication system, and converts the spreaded signal into a transmission signal. send. Since the present invention supports not only the first spreading method but also the second spreading method or the third spreading method, it is possible to alleviate the amplitude variation of the transmission signal caused by using the existing system while ensuring compatibility with the existing system. Therefore, there is an advantage in that the frequency with which the transmission signal is turned on / off can be reduced.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. For example, a specific embodiment of the present invention has been described for an example applied to a direct spread / code division multiple access (DS / CDMA) communication system. However, it should be noted that the present invention can be used not only for code division multiple access communication systems but also for other spread spectrum communication systems. In addition, although a specific embodiment of the present invention has been described with respect to an apparatus for generating an orthogonal coded information signal as a spread signal, it can be equally applied to an apparatus for generating an information signal encoded according to a method other than orthogonal coding as a spread signal. have. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims (14)

A spreading signal generating device of a spread spectrum communication system, An I-arm PN code generator for generating a child (I) cancer pseudo noise (PN) code, A Q-arm PN code generator for generating a queue (Q) arm PN code, A first spreader for generating a first I-arm spread signal and a first Q-arm spread signal by multiplying the encoded information signal by the I-arm PN code and the Q-arm PN code; Inverts any one of the Q-arm PN code and the I-arm PN code, and multiplies the encoded information signal by the Q-arm PN code or the inverted Q-arm PN code to generate a second I-arm spread signal. A second spreader for generating a second Q-arm spread signal by multiplying the encoded information signal by the I-arm PN code or the inverted I-arm PN code; The first diffuser and the second diffuser are configured to have a structure including the structures of the first diffuser and the second diffuser, and input the coded information signal. Generate a cancer spread signal, add the first I cancer spread signal and the second I cancer spread signal to generate a third I cancer spread signal, and add the first Q cancer spread signal and the second Q cancer spread signal to form a third Q cancer spread. A third spreader generating a spread signal; And at least a selector for selecting and outputting an I-arm spread signal and a Q-arm spread signal generated by the first spreader, the second spreader or the third spreader according to an applied spreading mode determination signal. Diffusion signal generating device characterized in that. The method of claim 1, wherein the selection unit, A first selector which selects and outputs an I-arm spread signal from among the I-arm spread signals generated by the first spreader, the second spreader or the third spreader according to the spreading mode determination signal; And a second selector configured to select and output any one of the Q arm spread signals generated by the first spreader, the second spreader, or the third spreader according to the spreading mode determination signal. Spreading signal generating device. The method of claim 1, wherein the first diffusion unit, A first multiplier for generating the first I arm spread signal by multiplying the encoded information signal by the I arm PN code; And a second multiplier for multiplying the encoded information signal by the Q-arm PN code to generate the first Q-arm spread signal. The method of claim 1, wherein the second diffusion unit, An inverter for inverting the Q-arm PN code, A first multiplier for multiplying the coded information signal by the inverted Q-arm PN code to generate the multiplication result as the second I-arm spread signal; And a second multiplier for multiplying the encoded information signal by the I-arm PN code to generate the multiplication result as the second Q-arm spread signal. The method of claim 1, wherein the second diffusion unit, An inverter for inverting the I-arm PN code, A first multiplier for multiplying the encoded information signal by the Q-arm PN code to generate the multiplication result as the second I-arm spread signal; And a second multiplier configured to multiply the encoded information signal by the inverted I-arm PN code to generate the multiplication result as the second Q-arm spread signal. 6. The spreading signal generating apparatus according to claim 4 or 5, wherein the inverter is a multiplier that multiplies the Q arm PN code or the I arm PN code by a value of "-1". The method of claim 1, wherein the third diffusion unit, A first generation unit having the same structure as the first spreading unit and generating the first I arm spreading signal and the first Q arm spreading signal by inputting the encoded information signal; A second generation unit having the same structure as that of the second diffusion unit and configured to generate the second I arm spread signal and the second Q arm spread signal by inputting the encoded information signal; A first adder configured to add the first I cancer spread signal generated by the first generator and the first Q cancer spread signal generated by the second generator to output the third I cancer spread signal; And a second adder configured to output the third Q cancer spread signal by adding the second I cancer spread signal generated by the first generator and the second Q cancer spread signal generated by the second generator. Diffusion signal generator. In the transmitter of a spread spectrum communication system, A plurality of orthogonal code generators each generating orthogonal codes for each channel, A plurality of multipliers for multiplying the orthogonal codes generated by the orthogonal code generators and the respective channel information signals and outputting channel-specific eye (I) arm coded information signals and cue (Q) arm coded information signals; An I cancer PN code generator for generating an I cancer pseudo noise (PN) code, A Q cancer PN code generator for generating a Q cancer pseudo noise (PN) code, Each of the I-arm PN code and the Q-arm PN code is directly multiplied by the I-arm coded information signal and the Q-arm coded information signal according to a spreading method determination signal applied to each of the multipliers, or the I-arm. A plurality of intersections in which a PN code and one of the Q arm PN codes are inverted and then crossed to multiply the Q arm coded information signal and the I arm coded information signal to output an I arm spread signal and a Q arm spread signal. With controlled diffuser, A first adder for generating an I arm combined signal by adding I arm spread signals output from the cross control spreaders; A second adder generating a Q arm combined signal by adding Q arm spread signals output from the cross control spreaders; A first mixer for generating an I arm modulated signal by mixing a first carrier signal with the I arm combined signal; A second mixer for generating a Q arm modulated signal by mixing a second carrier signal with the Q arm combined signal; And an adder which adds the I-arm modulated signal and the Q-arm modulated signal and outputs them as a transmission signal. The method of claim 8, wherein each cross-control diffuser, A first spreader configured to generate a first I-arm spread signal by multiplying the I-arm coded information signal by the I-arm PN code, and generate a first Q-arm spread signal by multiplying the Q-arm coded information signal by the Q-arm PN code Wow, Inverts any one of the Q-arm PN code and the I-arm PN code, and multiplies the I-arm encoded information signal by the Q-arm PN code or the inverted Q-arm PN code to generate a second I-arm spread signal. A second spreader for generating a second Q-arm spread signal by multiplying the I-arm PN code or the inverted I-arm PN code by the Q-arm coded information signal; The first diffuser and the second diffuser have a structure including a structure including the structures of the first and second spreaders, wherein the I-arm coded information signal and the Q-arm coded information signal are inputted. A 2I arm spread signal and the 2Q arm spread signal are generated, and the first I arm spread signal and the 2I arm spread signal are added to generate a 3I arm spread signal and the 1Q arm spread signal and the 2Q arm spread. A third spreader for adding a spread signal to generate a third Q dark spread signal; And a selector which selects and outputs an I arm spread signal and a Q arm spread signal generated by the first spreader, the second spreader or the third spreader according to the spreading mode determination signal. . The method of claim 9, wherein the first diffusion unit, A first multiplier for generating the first I arm spread signal by multiplying the I arm code information signal by the I arm PN code; And a second multiplier for generating the first Q arm spread signal by multiplying the Q arm coded information signal by the Q arm PN code. The method of claim 9, wherein the second diffusion unit, An inverter for inverting the Q-arm PN code, A first multiplier which multiplies the inverted Q-arm PN code by the I-arm encoded information signal and generates the multiplication result as the second I-arm spread signal; And a second multiplier configured to multiply the Q-arm coded information signal by the I-arm PN code to generate the multiplication result as the second Q-arm spread signal. The method of claim 9, wherein the second diffusion unit, An inverter for inverting the I-arm PN code, A first multiplier for multiplying the I-arm coded information signal by the Q-arm PN code to generate the multiplication result as the second I-arm spread signal; And a second multiplier configured to multiply the Q-arm coded information signal by the inverted I-arm PN code to generate the multiplication result as the second Q-arm spread signal. The transmitter of claim 11 or 12, wherein the inverter is a multiplier that multiplies the Q arm PN code or the I arm PN code by a value of "-1". The method of claim 9, wherein the third diffusion unit, A first generation unit having the same structure as that of the first spreading unit and generating the first I dark spread signal and the first Q dark spread signal by inputting the I dark encoded information signal and the Q dark encoded information signal; A second generation unit having the same structure as that of the second diffusion unit and configured to generate the second I arm spread signal and the second Q arm spread signal by inputting the I arm coded information signal and the Q arm coded information signal; A first adder configured to add the first I cancer spread signal generated by the first generator and the first Q cancer spread signal generated by the second generator to output the third I cancer spread signal; And a second adder configured to output the third Q cancer spread signal by adding the second I cancer spread signal generated by the first generator and the second Q cancer spread signal generated by the second generator. transmitter.