JPH11177528A - Hierarchical delay multiplex spread spectrum communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the communication equipment that conducts transmission reception by the hierarchical transmission system in the spread spectrum communication adopting delay multiplex. SOLUTION: Transmission data are given to a hierarchical circuit 1, where a data string m1 is converted into two stages of layers with higher importance than m2, each data string is differential coded at differential coding circuits 2, 3, where I1, Q1 and I2, Q2 having provision for QPSK are generated. The data are spread by spread sections 5-8 by using the Barker code from a spread code generating circuit 4, data obtained spreading the string m2 are given to delay sections 9, 10, where a delay by 3 tips is given. Data at the same time are multiplexed by multiplexer.sections 11, 12, the multiplexed data are modulated by guadrature modulation section 13, the frequency is converted into a prescribed frequency at a frequency converter 14 and the converted frequency signal is sent from an antenna 15. In the case of a delay by 3 tips, the string m1 has 8 chips and the string m2 has 3 tips in the delay interval from a preceding multiplexed wave, and then the string m1 is more stably demodulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless communication or wired communication using spread spectrum, and more particularly, to a spread spectrum communication system disclosed in Japanese Patent Application Laid-Open No. 9-55714 (hereinafter referred to as "delay multiplexing"). The present invention relates to a system capable of flexibly transmitting hierarchical information and a transmission / reception device thereof.

[0002]

2. Description of the Related Art In recent years, a spread spectrum communication system has attracted attention as a new communication system. The modulation system used for general data communication is a narrow band modulation system, which can be realized with a relatively small circuit. However, for indoor (office, factory, etc.), multipath or narrow band colored noise It has the problem of being weak. On the other hand, the spread spectrum communication method has an advantage that these problems can be solved because the data spectrum is spread by a spread code and transmitted in a wide band.

However, on the other hand, high-speed data transmission has been difficult because a wide band is required for the data transmission speed. For example, by spreading with an 11-chip spreading code, Q
Considering the case of transmitting by PSK (Quadrature Phase Shift Keying) modulation, a 22 MHz band is required for 2 Mbps data transmission. When transmitting 10 Mbps data, a 110 MHz band is required. However, since the band that can be transmitted wirelessly is limited, high-speed data transmission has been difficult.

Therefore, as a means for performing high-speed transmission in a limited band, a method of delaying and multiplexing a spread signal (hereinafter, referred to as a delay multiplexing method) has been proposed (Japanese Patent Laid-Open No. Hei 9 (1994)).
-55714, reference). By using this method, high-speed transmission can be performed in a limited band. In the above example (11 chip spreading code, QPSK modulation)
When this delay multiplexing method is used, 2 multiplexing results in 4 Mbps.
When 5 data are multiplexed, 10 Mbps data can be communicated.

FIG. 11 shows an example of the transmission system of the delay multiplex system. However, in order to simplify the explanation, the modulation method is BPS
K (Binary Phase Shift Keying). Less than,
The configuration will be described with reference to FIG. FIG. 11 shows an example in which a multiplier and a delay element are added one by one in parallel to the example shown in JP-A-9-55714, and the number of multiplexes is five. The data generated by the data generating unit 201 is converted into a differential signal by a differential encoding unit 202, and then parallel-converted by a serial / parallel converting unit 203 (hereinafter referred to as an S / P converting unit) into a number to be multiplexed.

Thereafter, the multipliers 205 to 209 spread the PN code generated by the PN generator 204 over each data. Next, each signal is delayed by the delay elements 210 to 214, further multiplexed by the multiplexer 215, modulated by the multi-valued digital signal by the modulator 216, and transmitted by the frequency converter 217. , And transmitted by the antenna 218.

Here, as an example, a PN code generation circuit 4
Let us consider a case in which an 11-chip Barker code is prepared and the data is multiplexed five times. The Barker code is (10110111)
000). In the delay unit, considering that 11 chips are divided into five multiplexes, four are delays of two chips and one is delay of three chips. Here, suppose that the delay difference between the chips is 2,
Assuming that each chip is 2, 2, 2, or 3 chips, the first delay element 210 has a delay of 0 chip or less (that is, no delay) and the delay elements 211 to 214 have delay times of 2, 4, 6, and 8 chips, respectively. Will have.

FIG. 12 shows an example of the configuration of a receiver for receiving a signal thus delayed and multiplexed. The signal received by the antenna 231 is frequency-converted by the RF / IF converter 232 and the IF / BB converter 233 to be converted into a baseband signal, and then correlated by the correlator 232. This correlation output is output to the correlation synchronization circuit 235 and the latch unit 236. The latch unit 236 latches the correlation output at the timing obtained by the correlation synchronization circuit 235 (in the case of this example, the correlation synchronization circuit has two chips, two chips, two chips, two chips,
A signal is generated at a timing of three chips), and the canceller unit 237 cancels the influence of the multiplex wave. afterwards,
The differential demodulation unit 238 performs differential demodulation, and the discrimination unit 239 discriminates and demodulates.

In the canceller section, a canceller that has already been filed by the same applicant as Japanese Patent Application No. 8-209917 is used. Here, the effect will be briefly described. In the case of such a system with five delay multiplexes, if the absolute value of the correlation output in the case of no multiplexing is 11, the correlation output is 7, 9, 11, 13,.
Fifteen. However, by adding the influencing correlation value, dividing by 8, and adding to the data to be demodulated, the correlation output converges to 10.5,
Variations are eliminated, and the error rate characteristics are improved. In the example of five-multiplexing shown here, the eight data before and after the data to be demodulated overlap on the time axis, which seems to have an effect. In fact, four of them are that the overlapping chip portions are orthogonal. And only four multiplexes will have an effect.

This is proved by an equation for an arbitrary multiplex number as follows. However, in the following proof, it is assumed that the number of delay chips is not composed of only odd chips (it is assumed that the delay of even chips is always included), and the spreading code is a Barker code of 11 chips. I have. In the case of an m-multiplex system, a certain n-th correlation value is affected by m-1 multiplex waves before and after due to the characteristics of the Barker codes before and after. Therefore, assuming that the original correlation value of the n-th data (value not affected by the multiplex wave) is Cn, the odd correlation and even correlation of the Barker code are ± 1, and
Correlation value Cn 'obtained in receiver affected by multiplex wave
Is

[0011]

(Equation 1)

## EQU1 ## In order to cancel the influence of the delayed wave, it is desired to demodulate by adding the correlation value of the multiplexed waves of 1 / B (B differs depending on the number of multiplexing, and B can be canceled by setting B to an appropriate value). The data correlation value Cn ″ is

[0013]

(Equation 2)

In the above equation (4), it is understood that the influence of the multiplex wave can be canceled by appropriately setting the value of B according to the number of multiplexes and setting the coefficient of the second term of the equation (4) to 0.

On the other hand, various schemes for performing hierarchical transmission have been proposed. For example, Japanese Patent Application Laid-Open No. 5-276221 discloses a method for implementing hierarchical transmission by modulating the distance of a code in a signal space at unequal intervals so as to change the probability of occurrence of errors with respect to noise. Is disclosed. In recent years, for the OFDM (orthogonal frequency division multiplexing) method which is considered to be suitable for mobile communication transmission, for example, Japanese Patent Application Laid-Open No. 7-321765 describes a layered transmission method. This system utilizes multi-carrier transmission, and realizes stable hierarchical transmission by changing the modulation system depending on the carrier.

[0016]

As described above, in conventional spread spectrum communication, high-speed transmission is difficult when a limited band is used. Is essential. On the other hand, applications such as image transmission become possible when the transmission speed is improved.However, when digital image data is transmitted with a uniform error rate characteristic, if an error occurs in an important data portion, the image quality becomes remarkably high. There is a problem of deterioration. Also, from the viewpoint of multimedia communication, there is an increasing demand for simultaneous transmission of images, sounds, and even data. In the case of such communication, error rate characteristics required for transmission are different from each other.

Although the present invention recognizes that high-speed data communication and hierarchical communication of data are indispensable in delay-multiplexed spread-spectrum communication, there has been no solution to this point. In view of the above situation, it is an object of the present invention to provide a communication apparatus that performs transmission and reception by a hierarchical transmission scheme in spread spectrum communication using delay multiplexing.

[0018]

According to a first aspect of the present invention, there is provided a serial / parallel converter for performing serial / parallel conversion of a transmission data sequence into n stages (n is an integer of 2 or more and a number of diffusion chips or less) in accordance with allocation of a multiplex number. Means for spreading the transmission data of the n stages converted by the serial / parallel conversion means with the same spreading code; and spreading the data spread by the spreading means with a predetermined number of chips (an integer of 1 or more). ), Multiplexing means for multiplexing each data delayed by the delay means, and transmission means for performing a predetermined modulation process on the multiplexed data from the multiplexing means and transmitting the multiplexed data at a predetermined transmission frequency. A communication apparatus based on a delay multiplex spread spectrum communication system, wherein the transmission data sequence is provided m stages (m is Above, comprising a layered means for layering the n an integer), among the layered data in m stages by hierarchical layering means, as more importance is high hierarchical data,
The delay interval set by the delay means is increased. According to the first aspect of the present invention, the transmission data sequence is hierarchized in two or more stages (m stages), and when these data are transmitted using the delay multiplexing method, the data of the hierarchy having higher importance is delayed. By increasing the delay interval (the number of delay chips) of multiplexing (m stages or more), the effect of delay waves is reduced, and by selecting a layer according to the nature of data, the multiplexing communication suitable for multimedia can be performed. to enable.

According to a second aspect of the present invention, there is provided a multiplex number assigning means for assigning a multiplex number to a transmission data string, and the transmission data string is assigned n according to the multiplex number assignment by the multiplex number assignment means.
Serial / parallel conversion means for serial / parallel conversion into stages (n is an integer of 2 or more and the number of spreading chips or less), and spreads each of the n stages of transmission data converted by the serial / parallel conversion means with the same spreading code. Spreading means, delay means for delaying the data spread by the spreading means by a predetermined number of chips (an integer of 1 or more), multiplexing means for multiplexing each data delayed by the delay means, A communication apparatus based on a delay multiplex spread spectrum communication system having a transmission means for performing a predetermined modulation process on multiplexed data from the means and transmitting the multiplexed data at a predetermined transmission frequency, wherein the transmission data is provided before the serial / parallel conversion means. A layering means for layering the column into m stages (m is an integer of 2 or more and n or less) in accordance with the degree of importance; Among the data, as the more importance is low hierarchical data, in which to assign a number to multiplex number by the multiplex number allocating means. According to the second aspect of the present invention, the transmission data sequence is hierarchized in two or more stages (m stages), and when these data are transmitted using the delay multiplexing method, the data of the hierarchy having higher importance is delayed. The error rate characteristic is improved by reducing the number of multiplexes (m or more stages), and the multiplex communication suitable for multimedia is enabled by selecting a layer according to the nature of data.

According to a third aspect of the present invention, in the first or second aspect, there is provided means for multiplexing and transmitting information relating to hierarchization as a control signal. According to the third aspect of the present invention, in addition to the system of the first or second aspect, the transmitting side includes, as multiplexed information, a delay interval (number of delay chips), a multiplexed number, a data length, etc. Format, multiplexes the data into a transmission data sequence, and transmits the data. The receiving side demodulates the multiplexed information and generates a control signal based on the multiplexed information, thereby demodulating the transmission data according to the transmission method. To be able to do.

According to a fourth aspect of the present invention, there is provided a serial / parallel conversion means for serially / parallel converting a transmission data sequence into n stages (n is an integer of 2 or more and the number of diffusion chips or less) according to allocation of a multiplex number, and Spreading means for spreading each of the n-stage transmission data converted by the parallel conversion means with the same spreading code, and delay means for delaying the data spread by the spreading means by a predetermined number of chips (an integer of 1 or more). Multiplying means for multiplying each data delayed by the delay means by a predetermined coefficient; multiplexing means for multiplexing each data from the multiplying means; and performing a predetermined modulation process on the multiplexed data from the multiplexing means. A communication device using a delay multiplex spread spectrum communication system having a transmitting means for performing transmission at a predetermined transmission frequency, wherein the transmitting means is provided at a stage prior to the serial / parallel converting means. There is provided a layering means for layering the data sequence into m levels (m is an integer of 2 or more and n or less) in accordance with the degree of importance. Of the data hierarchized into m levels by the layering means, The higher the level of the data, the larger the coefficient to be multiplied by the multiplication means.
According to the fourth aspect of the present invention, when the transmission data sequence is hierarchized by two or more stages (m stages), and then when these data are transmitted by using a delay multiplexing method in which delay multiplexing is assigned by m stages or more, For data of a layer of high importance, the error rate characteristics are improved by increasing the amplitude of the multiplexed wave (increase of transmission power), and by selecting the layer according to the characteristics of the data, it is suitable for multimedia. Enable multiplex communication.

[0022]

FIG. 1 is a block diagram of a transmitter according to a first embodiment of the present invention. In order to simplify the description, the present embodiment describes a case where two multiplexing is used as the delay multiplexing method. As a spread code, an 11-chip Barker code is used as in the conventional example. The processing and operation of this embodiment will be described with reference to FIG.
First, the transmission data is converted by the layering circuit 1 into two layers. In this example, it is assumed that the data string m1 has higher importance than the data string m2. The respective data strings are differentially encoded by the differential encoding circuits 2 and 3, respectively. In this embodiment, QPSK is assumed, so that I1, Q1 and I1
2, Q2.

The differentially encoded data is spread by the spreading units 5 to 8 using the Barker code generated by the spreading code generation circuit 4. Of the data, the data after spreading of the data string m2 is input to the delay units 9 and 10. In the delay unit, for example, 3
A chip delay is provided. And multiplexing units 11 and 12
At the same time, data at the same time is multiplexed, modulated by the quadrature modulator 13, converted to a predetermined frequency by the frequency converter 14, and transmitted through the antenna 15.

FIG. 2 is a block diagram showing the configuration of the receiver according to this embodiment. The processing and operation of this embodiment will be described with reference to FIG. The signal received by the antenna 21 is frequency-converted to an IF by a frequency conversion circuit 22 and is converted to a baseband frequency by a quadrature demodulation unit 23. The converted reception signals are converted into analog / digital converters 24 and 25 (hereinafter, referred to as “analog / digital converters”).
A / D converter) converts the signal into a digital signal,
Correlations are taken at 6,27. This correlator output is input to the correlation synchronization circuit 28 to obtain synchronization. The correlation value is latched by the latch units 29 and 30 based on the output of the correlation synchronization circuit.

Thereafter, the canceller sections 31 and 3 respectively
2 to remove the effect of the multiplex wave. Then, this canceller output is subjected to serial / parallel conversion by the S / P converter 34, and is converted into two series of a reception data string relating to the data string m1 and a reception data string relating to the data string m2. Then, they are decoded by the differential decoding circuits 35 and 36, respectively.
In the information data reconstructing unit 37, the original information data is restored.

The reason why this configuration causes a difference in the error rate characteristics of the data strings m1 and m2 will be described. For example, in wireless communication in a room, a delay wave exists, and the propagation environment changes due to movement of a person or the like. 4 shows an example of a delay profile in a room in FIG. 3. In FIG. 3, the horizontal axis represents time, and the vertical axis represents power. When the delay multiplexing method is used in such an environment, when the delay time for multiplexing (that is, the number of delay chips × the time of one chip = Ts) approaches T1 in FIG. When the influence starts to occur and reaches T2, the error rate cannot be completely ignored, and the error rate characteristic deteriorates. This is largely due to the fact that the delayed wave of the multiplex wave has a correlation when the correlation of the desired wave to be demodulated is detected. Therefore, the influence of the delay wave of the multiplex wave becomes more difficult as the number of delay chips increases. In the embodiment shown here, the number of delay chips given to the data string m1 is 0 and the number of delay chips given to m2 is 3, so that the number of delay chips from the previous multiplex wave is the data string m1 This means that 8 chips (11-3) and the data string m2 are 3 chips, and it can be seen that m1 can perform more stable demodulation. Therefore, in this embodiment, layered transmission of transmission data for a delayed wave can be performed.

FIG. 7 shows an example in which hierarchical information is temporally multiplexed on transmission data. This embodiment shows an example in which the multiplexed information of the first embodiment, that is, the number of delay chips is inserted into the layered information of the header. By doing so, the receiver can read the layered information from the header and feed it back to the receiver, and can perform layered transmission according to the propagation environment. In addition, the number of delay chips can be changed in the middle, and the hierarchical structure can be realized in multiple sequences.

FIG. 5 shows a block diagram of a transmitter according to the second embodiment of the present invention. In the present embodiment, a case where one to three multiplexes are used as the delay multiplex system is described. The delay interval is a repetition of 5 chips and 6 chips in the case of two multiplexes, and is a repetition of 4 chips, 4 chips and 3 chips in the case of three multiplexes. As the spreading code, an 11-chip Barker code is used as in the conventional example. The transmission data is converted by the layering circuit 41 into three layers m1 to m3. Where m
The importance is assumed to be higher in the order of 1, m2, and m3. In the present embodiment, the transmission data sequence is transmitted with a frame as one unit. For example, 1/3 of the frame is single (no multiplexing),
The next 1/3 is transmitted by 2 multiplexing, and the remaining 1/3 is transmitted by 3 multiplexing (see FIG. 4).

Accordingly, the layering circuit 41 temporarily stores one frame to be transmitted in a buffer and outputs the frames in the order of layers. First, the data string m1, then m2, and finally m3
Output in the order of When the data sequence m1 is output, the data sequence is differentially encoded by the differential encoding circuit 42,
In this embodiment, since QPSK is assumed, I, Q
Is output. Since m1 is single, the S / P converters 43 and 44 are passed through, that is, I
Only 1, Q1 is used. Using the Barker code generated by the spreading code generation circuit 45, the data is spread by the spreading units 46 and 49 and input to the multiplexing units 56 and 57. When single, no operation is actually performed in the multiplexing units 56 and 57.
Then, the signal is modulated by the quadrature modulator 58 and the frequency converter 59
Is converted to a predetermined frequency and transmitted through the antenna 60.

When the data string m2 is output, the data string is differentially encoded by the differential encoding circuit 42, and the I, Q
Is output. In the case of m2, since there are two multiplexes, the S / P converters 43 and 44 perform S / P conversion to two outputs, that is, I1, I2, Q1, and Q2 are used. Using the Barker code generated by the spreading code generation circuit 45, the spreading units 46, 47, 49, and 50 spread the data, and the delay units 52 and 54 add a 5-chip delay to the data after I2 and Q2 spreading. And input to the multiplexing units 56 and 57. Thereafter, the signal is modulated by the quadrature modulator 58, converted to a predetermined frequency by the frequency converter 59, and transmitted through the antenna 60.

When the data string m3 is output, the data string is differentially encoded by the differential encoding circuit 42, and the I, Q
Is output. In the case of m3, since there are three multiplexes, the S / P converters 43 and 44 perform S / P conversion to three outputs, that is, all of I1 to I3 and Q1 to Q3 are used.
Using the Barker code generated by the spreading code generation circuit 45, the data is spread by the spreading units 46 to 48 and 49 to 51,
The data after spreading I2 and Q2 has a delay of 4 chips,
The data after the spreading of Q3 and Q3 are delayed by 8 chips and input to the multiplexing units 56 and 57. Thereafter, the signal is modulated by the quadrature modulator 58, converted to a predetermined frequency by the frequency converter 59, and transmitted through the antenna 60. The quadrature modulator 58 controls the transmission power to be constant for an arbitrary number of multiplexes.

FIG. 6 shows a transmitter according to the second embodiment.
FIG. 3 is a block diagram illustrating a configuration of a receiver. The signal received by the antenna 71 is frequency-converted to an IF by a frequency conversion circuit 72, and is converted to a baseband frequency by a quadrature demodulation unit 73. The converted received signal is converted into a digital signal by analog / digital converters 74 and 75,
At 77 a correlation is taken. The correlation outputs of the correlators 76 and 77 are input to a correlation synchronization circuit 78 and synchronized. Then, the latches 79 and 80 are output from the correlation synchronization circuit.
, The correlation value is latched. Thereafter, the latched correlation values are input to canceller units 81 and 82, respectively, to remove the influence of the multiplex wave. The information is decoded by the differential decoding circuit 83, and the original information data is restored by the information data reconstruction unit 84.

The reason why the error rate characteristics of the data strings m1 to m3 are different due to this configuration will be described. Although shown in the configuration of the transmitter, in the present embodiment, control is performed so that the transmission average power is constant regardless of the number of multiplexes transmitted. As a result, the power per wave decreases as the number of multiplexes increases. For example, based on the power of one wave, the power per one wave is reduced by 3.0 dB in the case of two multiplexing, 4.7 dB in the case of three waves, and so on.
Down by 6.0 dB for 4 waves and 7.0 dB for 5 waves. In the present embodiment, since an example of 1 to 3 multiplex is given, m1 and m
In the data string of No. 3, a difference of 4.7 dB appears in the C / N characteristic. Also, of course, the effect of the delayed wave is less likely to be exerted on the one-multiplex part than on the three-multiplex part.

FIG. 8 shows an example in which hierarchical information is temporally multiplexed with transmission data. In the present embodiment, an example is shown in which the multiplex information of the second embodiment, that is, data relating to the number of multiplexes and the data length is inserted into the hierarchical information of the header. By doing so, the receiver can read the layered information from the header and feed it back to the receiver, and can perform layered transmission according to the propagation environment. In addition, since the data length of each multiplexed wave can be arbitrarily selected on the transmission side, the total number of transmission bits included in the frame can be varied, making it possible to make a configuration more suitable for multimedia communication of images, voice, data, etc. Become.

FIG. 9 shows a block diagram of a transmitter according to the third embodiment of the present invention. In the present embodiment, in order to simplify the description, a case where three multiplexing is used as the delay multiplexing method is described. The delay interval is a repetition of 4 chips, 4 chips, and 3 chips. As the spreading code, an 11-chip Barker code is used as in the conventional example.
The transmission data is converted by the layering circuit 91 into three layers m1 to m3. However, the importance is assumed to be higher in the order of m1, m2, and m3.

The data sequence m1 is differentially encoded by the differential encoding circuit 92 and output as two streams I1 and Q1. These data are spread by the spreading units 95 and 98, respectively, using the Barker code generated by the spreading code generation circuit 101. Similarly, the data sequence m2 is differentially encoded by the differential encoding circuit 93, and outputs I2 and Q2, and is spread by the spreading units 96 and 99.
The delay units 102 and 104 provide a 4-chip delay.
The data sequence m3 is also differentially encoded by the differential encoding circuit 94, and outputs I3 and Q3. The data sequence m3 is spread by the spreading units 97 and 100, and the delay units 103 and 105 provide a delay of 8 chips.

Amplitude coefficient multiplication circuits 106 to 108, 109
At ~ 111, the data strings m1-m3 are multiplied by a predetermined amplitude coefficient. For example, let each amplitude coefficient be A1,
Assuming that A2 and A3, the assignment may be performed so that A1>A2> A3. After that, the multiplexing unit 112 for each of I and Q,
These data are multiplexed at 113, modulated by a quadrature modulator 114, converted to a predetermined frequency by a frequency converter 115,
Transmitted via antenna 116.

FIG. 10 is a block diagram showing a configuration of a receiver for the transmitter according to the third embodiment. Antenna 1
The signal received at 21 is frequency-converted to an IF by a frequency conversion circuit 122, and is converted to a baseband frequency by a quadrature demodulation unit 123. The converted reception signals I and Q are analog /
The signals are converted into digital signals by digital converters 124 and 125, and are correlated by correlators 126 and 127. Correlation outputs from the correlators 126 and 127 are output to the correlation synchronization circuit 1
28 and synchronized. The correlation value is latched by the latch units 129 and 130 based on the output of the correlation synchronization circuit.

Thereafter, the latched correlation values are input to canceller units 131 and 132, respectively, to remove the influence of the multiplex wave. In the case of the present embodiment, the amplitude ratios of the respective multiplexed waves are different. This is because the terms of the respective amplitude ratios are substituted for Cn in the proof equations (1) to (4) shown as the conventional example, and Cn = An It can be seen that the influence of the multiplex wave can be similarly canceled by using × Cn. Thereafter, the signals are output to the three systems by the S / P converters 133 and 134, are respectively decoded by the differential decoding circuits 135 to 137, and the original information data is restored by the information data reconstruction unit 138.

According to this configuration, each multiplexed wave is weighted by the amplitude coefficient to give a difference in the error rate characteristic, and the layers can be hierarchized. This corresponds to Embodiment 1 or 2.
This is advantageous in that a hierarchical structure can be freely provided, and the receiver is not affected at all. Further, in the above embodiment, the case where the number m of layered data and the number n of delay multiplexes are the same is shown. However, if n> m, the required transmission rate of each layer of data to be layered is required. Are used when the numbers are different. For example,
If m = 2 and the required transmission rate ratio between the upper layer (higher importance data) and the lower layer (low importance data) is 1: 2,
By setting n = 3 and allocating one wave to the upper layer and the remaining two waves to the lower layer of the data to be delayed and multiplexed, it is possible to cope with the case where the transmission rates between the layers are different.

[0041]

According to the first aspect of the present invention, in a spread spectrum communication system using a delay multiplexing system, a transmission data sequence is hierarchized into m stages (two or more stages) on the transmission side, and these are further divided into n stages (m stages). (More than one stage), the more important the transmission data, the longer the delay interval (the number of delay chips) during delay multiplexing, thereby reducing the effect of the delay wave and increasing the difference in the error rate characteristics. By providing this, layered transmission suitable for image communication or multimedia communication is realized.

According to a second aspect of the present invention, in a spread spectrum communication system using a delay multiplexing system, a transmission data sequence is hierarchized into m stages (two or more stages) on the transmitting side, and further, they are divided into n stages (m stages or more). ), The transmission data having a higher importance is assigned to the delay wave, and the number of multiplexing, ie, n, is reduced in the delay multiplexing so that the error rate characteristics are different. Realize suitable hierarchical transmission.

According to the third aspect of the present invention, in addition to the effect of the first aspect, the delay interval information (the number of delay chips) set in accordance with the hierarchy as multiplexed information formatted in a header portion including transmission data is provided. The receiving apparatus inserts and receives the data of the number of delay chips extracted and restored from the transmission data block as a control signal to perform reception processing, thereby automatically receiving the hierarchical transmission signal corresponding to a change in transmission conditions. Can be done Further, in addition to the effect of the second aspect, information of the number of multiplexes and the data length set according to the layering is inserted as multiplexed information formatted in the bed part accompanying the transmission data, and the transmission data block By performing reception processing using the number of multiplexes and the data length extracted and restored from the control signal as a control signal, it is possible to automatically receive the hierarchical transmission signal that can respond to changes in transmission conditions.

According to a fourth aspect of the present invention, in a spread spectrum communication system using a delay multiplexing system, transmission data is hierarchized into m stages (two or more stages) on the transmitting side, and further, they are n stages (m stages or more). The transmission data of higher importance is assigned to the delay wave of the delay wave, and the transmission power is increased during the delay multiplexing, so that the error rate characteristics are made different, so that the transmission data is more suitable for image communication or multimedia communication. Achieve hierarchical transmission.

[Brief description of the drawings]

FIG. 1 shows a block diagram of a transmitter according to a first embodiment of the present invention.

FIG. 2 shows a block diagram of a receiver for a delayed multiplex transmission signal by the transmitter of FIG.

FIG. 3 shows a power-time profile due to a delay wave in indoor wireless communication.

FIG. 4 shows an example of a multiplexing configuration of a transmission frame.

FIG. 5 shows a block diagram of a transmitter according to a second embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a receiver of a delay multiplex transmission signal by the transmitter of the embodiment of FIG. 5;

FIG. 7 shows an example in which hierarchical information is temporally multiplexed on transmission data.

FIG. 8 shows another example of temporally multiplexing hierarchical information on transmission data.

FIG. 9 shows a block diagram of a transmitter according to a third embodiment of the present invention.

FIG. 10 is a block diagram illustrating a configuration of a receiver of a delay multiplex transmission signal by the transmitter of the embodiment of FIG. 9;

FIG. 11 is a block diagram illustrating a conventional delay multiplex transmission system.

12 is a block diagram illustrating a receiving system of the delay multiplexed signal by the transmitting system of FIG. 11;

[Explanation of symbols]

1, 41, 91 ... hierarchical circuit, 2, 3, 42, 92, 9
3, 94... Differential encoding circuit, 4, 45, 101... Spreading code generation circuit, 5, 6, 7, 8, 46, 47, 48, 4
9,50,51,95,96,97,98,99,10
0: diffusion part, 9, 10, 52, 53, 54, 55, 10
2, 103, 104, 105 ... delay unit, 11, 12, 5
6, 57, 112, 113... Multiplexer, 13, 58, 11
4. Quadrature modulator, 14, 59, 115, 217 Frequency converter, 15, 21, 60, 71, 116, 121, 2
18, 231 ... antenna, 22, 72, 122 ... frequency conversion circuit, 23, 73, 123 ... quadrature demodulator, 24, 2
5, 74, 75, 124, 125 ... A / D converter, 2
6, 27, 76, 77, 126, 127, 234... Correlators, 28, 78, 128, 235.
9, 30, 79, 80, 129, 130, 236 latch part, 31, 32, 81, 82, 131, 132, 23
7. Canceller section, 33, 34, 43, 44, 13
3,134 ... S / P converter, 35,36,83,13
5,136,137 ... differential decoding circuit, 37,84,9
4,138 ... information data reconstructing unit, 106,107,1
08, 109, 110, 111 ... amplitude coefficient multiplication circuit, 2
01: Data generation unit, 202: Differential encoding unit, 203:
S / P converter, 204 ... PN generator, 205, 206,
207, 208, 209 Multiplier, 210, 211,
12, 213, 214: delay element, 215: multiplexer, 2
16: Modulation unit, 232: RF / IF conversion unit, 233: I
F / BB converter, 238... Differential demodulator, 239.

Claims (4)

[Claims] 1. A serial / parallel conversion means for serially / parallel converting a transmission data sequence into n stages (n is an integer of 2 or more and a number of diffusion chips or less) according to allocation of a multiplex number, and a serial / parallel conversion means. Spreading means for spreading each of the n-stage transmission data with the same spreading code; delay means for delaying the data spread by the spreading means by a predetermined number of chips (an integer of 1 or more); A multiplexing means for multiplexing each data delayed by the above, and a transmission means for performing a predetermined modulation process on the multiplexed data from the multiplexing means and transmitting the multiplexed data at a predetermined transmission frequency. The transmission data sequence is hierarchized into m stages (m is an integer of 2 or more and n or less) in accordance with the degree of importance before the serial / parallel conversion means. The data having a higher degree of importance among the data hierarchized in the m levels by the hierarchical means, the delay interval set by the delay means is made larger. Hierarchical delay multiplex spread spectrum communication device. 2. A multiplex number allocating means for allocating a multiplex number to a transmission data sequence, and the transmission data sequence is divided into n stages (n is an integer of 2 or more and the number of spreading chips or less) in accordance with the multiplex number allocation by the multiplex number allocating means. Serial / parallel conversion means for performing serial / parallel conversion; spreading means for spreading each of the n-stage transmission data converted by the serial / parallel conversion means with the same spreading code; and data spread by the spreading means. Delay means for delaying by a predetermined number of chips (an integer of 1 or more); multiplexing means for multiplexing each data delayed by the delay means; predetermined modulation processing for the multiplexed data from the multiplexing means; A communication device based on a delay multiplex spread spectrum communication system having a transmission means for transmitting at a transmission frequency of: A hierarchical means for hierarchizing the transmission data sequence into m stages (m is an integer of 2 or more and n or less) in accordance with the degree of importance; A hierarchical delay multiplex spread spectrum communication apparatus characterized in that the higher the number of layers, the more the number of multiplexes is allocated by the multiplex number allocating means to the data of the layer having lower importance. 3. The layered delay multiplex spread spectrum communication apparatus according to claim 1, further comprising means for multiplexing and transmitting information related to layering as a control signal. 4. A serial / parallel converter for serially / parallel-converting a transmission data sequence into n stages (n is an integer of 2 or more and a number of diffusion chips or less) according to allocation of a multiplex number, and the serial / parallel converter. Spreading means for spreading each of the n-stage transmission data with the same spreading code; delay means for delaying the data spread by the spreading means by a predetermined number of chips (an integer of 1 or more); Multiplying means for multiplying each data delayed by the above by a predetermined coefficient; multiplexing means for multiplexing each data from the multiplying means; performing a predetermined modulation process on the multiplexed data from the multiplexing means to a predetermined transmission frequency A communication device based on a delay multiplex spread spectrum communication system having a transmitting means for transmitting the transmission data string in a stage preceding the serial / parallel converting means. Hierarchization means for hierarchizing the data into m levels (m is an integer of 2 or more and n or less) in accordance with the degree of importance of the data. A hierarchical delay multiplex spread spectrum communication apparatus, wherein a coefficient to be multiplied by the multiplying means is increased for hierarchical data.