JPH09312590A - Spread spectrum communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deal with many kinds of information speeds. SOLUTION: Inputted information signals 811 are encoded at an encoder 813 by an information speed signal 812 and additionally sorted to plural groups to be a common speed from an information signal recomposing device 814. Then, signals ion each group are spread by a spread code in which the generating timing and the period are changed according to the signal 812. Then the spread groups on each group are added to make it a transmission signal 818.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can efficiently handle information signals of different transmission speeds, such as voice data and computer data, large-capacity information such as moving images, or real-time and large-capacity high-speed data. The present invention relates to a spread spectrum communication device.

[0002]

2. Description of the Related Art In the field of wired communication, it is possible to provide computer data and the like at different information rates by using packet communication technology. For this reason, in the field of wireless communication, measures are required for wireless LAN and the like. In order to solve this, conventionally, data is transmitted at different information transmission speeds by a method of adding speed information to a pilot signal.

In recent years, IS-95 standardized in the United States performs decoding processing at all variable information rates until the encoded signal can be decoded without adding speed information to the pilot signal. Accordingly, a method of determining the information speed is adopted. However, since the IS-95 system is mainly for communication such as voice, the information speed is 10kb.
It is intended for communication up to about ps (bits per second), and does not consider speeding up to about 10 Mbps, which is an information rate required for real-time transmission of moving images and the like.

[0004] Here, schematic configurations of a spread spectrum (SS) transmitter and a spread spectrum (SS) receiver in the IS-95 system are shown in FIGS. 11 and 12, respectively.
In the SS transmitter shown in FIG. 11, an information signal 411 having a different information rate depending on a data source is input to an encoding and information signal reconstructor 413. In the coding and information signal reconstructor 413, the information signal 411 is coded by the information rate signal 412. Further, according to the information rate signal 412, the information signal 411 of any information rate is obtained.
Even in this case, the information rate is added to the control bit for each coding period, and the common information rate is changed to the maximum information rate or more that the information signal 411 can take. Then, the information modulator 4
15, for example, QPSK-modulated, and further spread-spectrum-spread in a spread modulator 416 by a spread code generated by a spread code generator 414, and
17 is set.

In the SS receiver shown in FIG.
The spread spectrum received signal 421 is input to a despreading modulator 423 and is multiplied by the same spreading code as that of the SS transmitter generated by the despreading signal generator 422 to perform despreading processing. Next, the information demodulator 4
At 24, for example, the signal is QPSK demodulated, and is input to the decoding and information rate determiner 425. In order to determine the information rate of the information signal to be decoded, the decoding and information rate determiner 425 determines the information rate by repeating decoding corresponding to all information rates.
Then, decoding according to the determined information rate is performed. As a result, the original information signal can be obtained as the demodulated information signal 426.

Note that the received signal 421 is originally distributed to, for example, four circuits in order to perform RAKE reception, and each path of the received signal is inverted by the same spreading code having a different generation timing according to the delay time of the path. After the information is spread and demodulated, it is synthesized, but the configuration is not shown. Further, in order to cope with fading, two-branch antenna diversity is performed, but the illustration is also omitted. Further, illustration of the band limiting and high frequency (RF) units is also omitted.

[0007]

In the conventional SS transmitter, in order to cope with the information speed up to about 10 Mbps, the information modulator 415 always needs to modulate the information at about 10 Mbps. Further, in the SS receiver, in order to determine the information rate of the information signal to be decoded in the decoding and the information rate determination unit 425, decoding corresponding to all information rates is repeated to determine the information rate. I have to. Therefore, when the information rate that can be taken increases, the number of repetitions for determining the information rate in the decoder increases, and the decoding process becomes difficult. In addition, 10Mbps
In order to cope with the information speed up to about 10 Mbps, it is necessary to always demodulate at about 10 Mbps in the information demodulator 424 as well as the information modulator 415 on the transmission side.

In other words, in such an SS transmitter, a common control bit is added for each encoding cycle at the time of encoding, and at all information rates, the common information that is higher than the maximum information rate that can be obtained is obtained. Need to change to speed. Therefore, when the maximum possible information rate increases, the information modulator always needs to perform high-speed modulation. Also, in the SS receiver, when the maximum information rate that can be taken increases, the information demodulator 424 needs to always demodulate at a high speed, like the information modulator 415. Further, when the types of information rates that can be taken increase, the processing time in the decoder increases due to the decoding performed repeatedly to determine the information rate. Therefore, this method has a problem that it is not suitable for providing a service capable of obtaining various kinds of information speeds at high speed.

Further, the IS-95 system uses the
Since partial correlation is performed, deterioration due to cross-correlation can be considered, and a circuit load due to an increase in types of data rates that can be taken is large. Therefore, due to these effects, the requirements for the encoding unit and the decoding unit become strict. Further, in the case of a cyclic code evaluated as an ordinary PN code using an M-sequence, since there are very few types of spreading codes with respect to the number of spreading codes, a CDMA (CODE) having a high user bit rate of about 10 Mbps in indoor and outdoor environments. DIVISION MULTIPLE
ACCESS) It can be said that an inappropriate spreading code is used for communication.

Therefore, according to the present invention, it is not necessary to perform high-speed modulation / demodulation even when the information signal speed becomes high, and information can be transmitted with high quality when the information speed becomes low,
Still another object of the present invention is to provide a spectrum communication device that can perform a decoding process in a decoder only at a desired information rate. Further, the present invention provides a spectrum communication device capable of separating delayed waves and further combining them, and enabling unspecified large numbers of users to perform high-speed communication without unnecessarily increasing the chip rate. Has other purposes.

[0011]

In order to achieve the above object, a spread spectrum communication apparatus on the transmitting side of the present invention sets an input information signal to a predetermined speed by using an information speed signal of the input information signal. Information signal reconstructor for allocating to a plurality of streams, a code generator whose timing and period of spreading code generation are changed according to the information rate signal, and the same code generated by the code generator A spread modulator that spreads each signal on the plurality of sequences by spread codes having the same code length and different speeds, and means for adding and transmitting a plurality of outputs from the spread modulator. ing.

According to another aspect of the present invention, there is provided a receiving-side spread-spectrum communication apparatus for distributing a spread-spectrum received signal to a plurality of streams, and the same means provided for each of the plurality of streams. A plurality of matched filters configured to perform a despreading process with different spreading codes of the same code length at a code rate, and an information rate determination for determining a rate of an information signal to be demodulated based on output information of the matched filter; And a demodulated signal reconstructor for reconstructing the demodulated signals on the plurality of streams into the original information signals, demodulated according to the information rate obtained from the information rate determiner.
Furthermore, the spread spectrum communication apparatus according to the present invention may include both the above-described transmitting unit and the receiving unit.

According to the present invention, in the transmitter of the spread spectrum communication apparatus, the input information signal is divided into a plurality of streams having a predetermined speed by the speed information signal of the information signal, and the same information is transmitted. Since the signals on the respective sequences are spread with different spreading codes of the same code length at the code rate, it is not necessary to add a common control bit for each coding cycle, and the information modulator Since it is not necessary to perform modulation at a rate higher than the maximum possible information rate, the information modulation rate of the information modulator can be reduced and the circuit of the information modulator can be simplified. In addition, it becomes possible to transmit information with high quality when the information speed decreases.

In a spread spectrum receiver,
The received signal is divided into a plurality of streams, and each stream is despread with the same code rate and different despreading codes having the same code length. The speed of the information signal to be demodulated is determined instantaneously, and the demodulated signals on multiple sequences are reconstructed on the same sequence based on the obtained speed information. In addition, since it is not necessary to determine the speed information in the decoder, the information demodulation speed of the information demodulator is reduced, and the decoding time in the decoder is shortened. The circuits of the demodulator and the decoder can be simplified. In addition, it becomes possible to decode information with high quality when the information speed becomes low.

Further, in order to achieve the above-mentioned other object,
Another spread-spectrum communication device on the transmitting side of the present invention is to input the input information signal into a plurality of streams according to both or either of the information transmission rate of the input information signal and the radio propagation environment. The information signal reconstructor to be distributed, a code generator having a means for changing the timing and period of spreading code generation, the same code rate generated by the code generator, and different spreading codes of the same code length, A spread modulator that spreads each signal on a plurality of streams and a transmission unit that adds and outputs the outputs of a plurality of streams output from the spread modulator are provided.
Furthermore, in the other spread spectrum communication apparatus on the transmitting side of the present invention, at the time of initial transmission and the time of transmission of the input information thereafter, the number and / or period of the sequence of the spreading code to be used is changed. You may make it. Still further, in another spread spectrum communication apparatus on the transmission side according to the present invention, the code generator has a spreading code of the same code length and a spreading code type of about the Gold code, or a spreading code of the same code length than the M sequence. A large number of spreading sequences may be generated.

According to another aspect of the present invention, there is provided another spread-spectrum communication apparatus on the receiving side which achieves the above-mentioned other object, includes means for distributing a spread-spectrum received signal into a plurality of streams, and a means for distributing signals having the same code rate and code length. A matched filter provided for each of the plurality of streams, and information for determining a speed of an information signal to be demodulated based on output information of the matched filter. A speed determiner, comprising a demodulated signal reconstructor for demodulating the demodulated signals on the plurality of streams into an original information signal, demodulated according to the information rate obtained from the information rate determiner; At the time of standby and at the time of data reception, both or one of the number and the cycle of the sequence of the despreading code to be used is changed.

Further, in the other spread spectrum communication apparatus on the receiving side according to the present invention, at the time of data reception, at least one adjacent spreading code is different in units of one cycle of the spreading code on each of the plurality of sequences. To perform a despreading process by circulating a spreading code group,
The despreading code at this time may be a spreading code sequence of the same code length and a spreading code type of about the Gold code, or a spreading sequence of the same code length and a larger spreading code type than the M sequence.
In another spread spectrum communication apparatus of the present invention, both the above-mentioned transmitting side means and receiving side means may be provided.

According to another aspect of the present invention, there is provided a CD which can be used in a propagation environment in which a delayed wave is generated, and which can improve the initial synchronization probability at the time of reception.
A spread spectrum communication apparatus suitable for MA communication can be realized. Also, using one cycle of the spreading code as a unit,
By spreading adjacent spreading codes so as to be different spreading codes, it is possible to separate and further combine delayed waves exceeding one cycle of the spreading code, and furthermore, the spreading code has the same code length and a spreading code type of about the Gold code. A spread spectrum communication device suitable for CDMA communication that can be used by an unspecified number of users in a propagation environment in which a delayed wave is generated by using a spread sequence of the same code length or a spread sequence having more types of spread codes than the M sequence Can be realized.

[0019]

Next, a first embodiment of a spread spectrum communication apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is an example showing a configuration of a spread spectrum transmitter according to a first embodiment of the spread spectrum communication apparatus of the present invention. In this figure, the information signal 8
11 is encoded in the encoder 813 by the information rate signal 812. The encoded information signal 811 is
The information rate signal 81 inputted to the information signal reconstructor 814
After being converted into an information signal of the same speed by 2, the signal is distributed to k plural streams. The allocated information signal is input to the spread modulator 817, and the information rate signal 81
The spreading code PN generated by the spreading code generator 816 in which the timing and cycle of generation of the spreading code are changed by 2
By multiplying each information signal by 1-PNk,
The spectrum is spread. In this case, the spreading codes PN1 to PN1
The code speed (chip rate) of PNk is the same, and different spreading codes of the same code length are used. Here, k is a positive integer.

The k information signals spread in spectrum by the spread modulator 817 are modulated in the information modulator 815 by DBPSK modulation, QPSK modulation, offset QPSK modulation, or the like according to a predetermined modulation method. . That is, modulation is performed in units of u bits. Here, u is a positive integer, which is 1 for BPSK modulation and 2 for QPSK modulation. Then, the k signals modulated by the information modulator 815 are added by an adder to become a transmission signal 818.

FIG. 2A shows the signal form of the information signal 811 whose information rate is changed according to the data source, and FIG. 2B shows the signal form of the transmission signal 818 in the spread spectrum transmitter configured as described above. It is shown in b). However, here, for convenience of explanation, the modulation method of the information modulator 815 is BP
SK modulation method, that is, u = 1, and the spread code generator 8
It is assumed that sixteen spreading codes PN1 to PNk generated are of three types, that is, spreading codes PN1, PN2, and PN3. The period of the spreading codes PN1, PN2, PN3 is set to τ (sec.). The information signal ai is a 1 (bit) information signal because the modulation scheme is BPSK modulation. Here, i is a positive integer.

In FIG. 2A, state 1 indicates a case where the information signals a1, a2,... A17, a18 are set to the maximum information speed 3 / τ (bps) of an image signal or the like. In this case, since the speed of the input information signal is set to be three times the information speed allocated by the information signal reconstructor 814, the information signal is allocated to three systems. In this distribution, i of the information signal ai is 3m + 1 (where m is 0,
1, 2, .... ) Information signals a1, a4, a7
Are the first stream, the information signals a2, a5, a8 whose i of the information signal ai are 3m + 2 are the second stream, and the information signals a3, a6, whose i of the information signal ai are 3 (m + 1). a9 ・
Are assigned to the third series. Note that the speed of each of the sorted three information signals is 1/3, which is 1/3.
τ (bps).

As described above, the information signals distributed to the three systems in the information signal reconstructor 814 are
At 17, spread spectrum processing is performed, and the information modulator 815 performs BPSK modulation. In the spread modulator 817, the first sequence information signal a
, A4, a7,... Are subjected to a spread spectrum process by the spreading code PN1, and the second series of information signals a2, a5, a
Are spread-spectrum processed by the spreading code PN2, and the information signals a3, a6, a9,... Of the third sequence are spread-spectrum processed by the spreading code PN3. As a result, three series of transmission signals as shown in state 1 in FIG. 2B can be obtained. The three series of transmission signals are added and transmitted as a transmission signal 818.

State 2 is the information signals a1, a2, a3, a4
.. Show the case where the information rate is 2 / τ (bps). In this case, since the speed of the information signal is twice as high as the information speed assigned by the information signal reconstructor 814, the signal is divided into two systems and assigned. .., And the second series of information signals a2, a4, a6, in which the i of the information signal ai is an even number, and the first series of information signals a1, a3, a5,. And sorted out. The speed of the sorted two-sequence information signal is set to a common speed of 1 / τ (bps), which is half the speed.

As described above, the two-sequence information signals distributed in the information signal reconstructor 814 are
At 17, spread spectrum processing is performed, and the information modulator 815 performs BPSK modulation. In the spread modulator 817, the first sequence information signal a
, A3, a5... Are subjected to a spread spectrum process by the spreading code PN1, and the second series of information signals a2, a4, a
Are spread-spectrum processed by the spreading code PN2. In this case, the spreading code PN3 is not used. As a result, two series of transmission signals as shown in state 2 of FIG. 2B can be obtained. The two series of transmission signals are added and transmitted as a transmission signal 818.

State 3 is the information signals a1, a2, a3, a4
.. Indicate a case where the information rate is 1 / τ (bps). In this case, since the speed of the information signal is equal to the speed output by the information signal reconstructor 814, the information signal is output as it is as a series of information signals. The information signal of the first stream from the information signal reconstructor 814 is subjected to spread spectrum processing in the spread modulator 817 and is BPSK modulated by the information modulator 815. In the spread modulator 817, the first sequence information signals a1, a2, a3
Are spread-spectrum processed by the spreading code PN1. In this case, the spreading codes PN2 and PN3 are not used. As a result, a series of transmission signals as shown in state 3 in FIG. 2B can be obtained and transmitted as the transmission signal 818.

State 4 includes information signals a1, a2, a3,.
Indicates that the information rate is 1 / 2τ (bps). In this case, since the information speed is set to の of the speed of the information signal output from the information signal reconstructor 814, the information signal ai is output as the first sequence in the odd-numbered period of each τ. At the same time, the data is output as a second sequence in an even-numbered period for each τ. The output information signals ai having the same contents of the first and second streams are respectively spread-spectrum processed by spreading modulator 817 and BPSK-modulated by information modulator 815. Note that the speed of the two-sequence information signal output from the information signal reconstructor 814 is a common speed of 1 / τ (bps), which is twice the original information signal.

In the spread modulator 817, the information signals a1, a2, a3,.
1 are spread, and the information signals a1, a2, a3,... Of the second stream are spread by the spreading code PN2. In this case, the spreading code PN3
Is not used. As a result, two series of transmission signals as shown in state 4 of FIG. 2B can be obtained. The two series of transmission signals are added and transmitted as a transmission signal 818. Thus, the transmission signal 818 has the spreading code P
By N1 and spreading code PN2, each is 2τ (se
c. ) Interval, the signals are spread with a time difference of τ (sec.), That is, a time difference of one cycle of the spreading code, and these two sequences are added.

In state 5, the information signals a1, a2,.
This shows a case where the information rate is 1 / 3τ (bps). In this case, the information rate is the information signal reconstructor 814
, The information signal ai is output as a first series in the first τ period of the 3τ period, and the information signal ai is output in the second τ period of the 3τ period. The signal ai is output as a second stream, and 3
In the last τ period of the τ period, the information signal ai is output as a third sequence. The output three-sequence information signal ai having the same contents of the first to third streams is applied to the spread modulator 81.
7 is subjected to spread spectrum processing, and information modulator 815 carries out BPSK modulation. Note that the speed of the three series of information signals output from the information signal reconstructor 114 is 1 / τ, which is three times the original information signal.
(Bps).

In the spread modulator 817, the information signals a1, a2, a3,.
, And the second series of information signals a1, a2, a3,... Are spread by the spreading code PN2 and the third series of information signals a1,
are subjected to spread spectrum processing by the spreading code PN3. As a result, three series of transmission signals as shown in state 5 of FIG. 2B can be obtained. The three series of transmission signals are added and transmitted as a transmission signal 818. Thus, the transmission signal 818 has the spreading code P
With N1, spreading code PN2, and spreading code PN3,
Each is spread at an interval of 3τ (sec.) With a time difference of τ (sec.), That is, with a time difference of one cycle of the spreading code, and these three sequences are added.

As described above, by using three types of spreading codes composed of mutually different codes having the same code rate (chip rate) and the same code length, spread spectrum transmission of information signals of five different rates can be performed. It becomes possible.
Also, here, the case of three types of spreading codes has been described. However, in the case of k types, information signals of (2k-1) types of speeds can be transmitted in the same manner. Here, k is an integer of 2 or more. In this case, when the speed of the information signal from the input data source is high, the information speed is reduced and the signals are transmitted in parallel using a plurality of streams. If the speed of the information signal from the input data source is low, the information speed is increased so that information signals of the same content are transmitted in parallel using a plurality of streams. Therefore, it is possible to transmit from high-speed information to low-speed information using the transmission path of the same band, and in the case of low-speed information, high quality information can be transmitted.

Next, FIG. 3 shows an example of the configuration of the spread spectrum receiver in the spread spectrum communication apparatus of the present invention. In this figure, a received signal 821 is input to a despreading modulator 822 and subjected to despreading processing. In this case, the despreading modulator 822 performs despreading processing in k matched filters 1 to k that perform despreading processing corresponding to a plurality of sequences of spreading codes at the time of transmission. The matched filters 1 to k here are SAW (Surf
ace Acoustic Wave) It is assumed that the output can be obtained instantaneously asynchronously such as a matched filter or a digital matched filter.

The despreading received signals of a plurality of sequences from the despreading modulator 822 are input to the information signal speed decision unit 823 and the speed of the received signal is decided. The rate information signal 824 determined by the information signal rate determiner 823 is supplied to the information demodulator 825, the decoded signal reconstructor 826, and the decoder 827. In the information demodulator 825, demodulation corresponding to the modulation method used in the information modulator 815 of the transmitter is performed on the sequence in which the signal to be demodulated exists, in accordance with the speed information signal 824. This demodulated signal is input to the demodulated signal reconstructor 826 as a temporary demodulated signal 1, a temporary demodulated signal 2,... In demodulated signal reconstructor 826, k sequences of temporarily demodulated signals are reconstructed on the same sequence based on speed information signal 824. Next, in the decoder 827,
Decoding is performed based on the speed information signal 824.

FIG. 4 is a timing chart showing the operation of the spread spectrum receiver configured as described above. FIG. 4 shows a timing chart under the same conditions as those in FIG. Further, since there are three types of spread codes on the transmission side, three types of matched filters (matched filter 1, matched filter 2, matched filter 3) are also used.

State 1 is the highest information rate of 3 / τ (bps).
Is transmitted. A despread signal is output from matched filter 1 at intervals of τ (sec.), Which is one cycle of the spread code, and despread signals are output from matched filter 2 and matched filter 3 at the same time. As described above, by inputting the despread signals output in three series at the same time to the information signal rate determiner 823, it is instantaneously determined that the information rate is 3 / τ (bps). The three sequences of despread signals output from the despread modulator 822 are:
BPSK demodulation is performed based on the information rate signal 824 that is input to the information demodulator 825 and determined. 3 demodulated
The temporary demodulated signals 1, 2, 3 of the series are
6, the temporary demodulation signal 1, the temporary demodulation signal 2, and the temporary demodulation signal 3 are arranged in this order at a τ / 3 (sec.) Interval on a single time series, and the information rate is 3 / τ (bps). The information signal is demodulated.

Thus, the information signals transmitted in a plurality of streams are rearranged in the order of ai, ai + 1,... The demodulated signal rearranged into one system is subjected to a decoding process in a decoder 827 based on the information rate signal 824, and the original information signal is reproduced as a demodulated information signal 828.

State 2 shows a case where an information signal having an information rate of 2 / τ (bps) is transmitted. Matched filter 1
Output a despread signal at intervals of τ (sec.), And the matched filter 2 outputs a despread signal at the same time. However, nothing is output from the matched filter 3.
In this way, the despread signal output in two sequences at the same time is
By inputting to the information signal speed determiner 823, it is determined instantaneously that the information speed is 2 / τ (bps).
The two-sequence despread signal output from despread modulator 822 is input to information demodulator 825, and BPSK demodulated based on determined information rate signal 824. The demodulated two series of temporary demodulated signals 1 and 2 are demodulated signal reconstructor 82.
6, the temporary demodulated signal 1 and the temporary demodulated signal 2 are arranged in order on a single time series at an interval of τ / 2 (sec.), And an information signal having an information rate of 2 / τ (bps) is demodulated. You.

Thus, the information signals transmitted in a plurality of streams are rearranged in the order of ai, ai + 1,... The demodulated signal rearranged into one system is subjected to a decoding process in a decoder 827 based on the information rate signal 824, and the original information signal is reproduced as a demodulated information signal 828.

State 3 shows a case where an information signal having an information rate of 1 / τ (bps) is transmitted. A despread signal is output from the matched filter 1 at intervals of τ (sec.).
Nothing is output from the matched filters 2 and 3. As described above, by inputting the despread signal output only for one series to the information signal rate determiner 823, it is instantaneously determined that the information rate is 1 / τ (bps). The one-series despread signal output from despread modulator 822 is input to information demodulator 825, and is subjected to BPSK demodulation based on determined information rate signal 824.
The demodulated temporary demodulated signal 1 of one series is input to the demodulated signal reconstructor 826 and output as it is,
An information signal having an information rate of 1 / τ (bps) is demodulated.
This demodulated signal is subjected to a decoding process in a decoder 827 based on the information rate signal 824, and the demodulated information signal 8
As 28, the original information signal is reproduced.

State 4 indicates a case where an information signal having an information rate of 1 / 2τ (bps) is transmitted. Matched filter 1
Outputs despread signals at 2τ (sec.) Intervals,
The matched filter 2 is offset by τ (sec.) And outputs a despread signal at an interval of 2τ (sec.).
However, nothing is output from the matched filter 3. By inputting the output despread signal to the information signal rate determiner 823 in this way, the information rate becomes 1 / 2τ (b
ps).

The two series of despread signals output from the despreading modulator 822 are input to the information demodulator 825, and based on the determined information rate signal 824, BPSK is calculated.
Demodulated. The two demodulated tentative demodulated signals 1, 2 are
The information rate is input to the demodulated signal reconstructor 826, and the information rate is 1 / 2τ (bp)
The information signal of s) is demodulated. The synthesized demodulated signal is
Decoding is performed in the decoder 827 based on the information rate signal 824, and the original information signal is reproduced as the demodulated information signal 828.

State 5 shows a case where an information signal having an information rate of 1 / 3τ (bps) is transmitted. Matched filter 1
Outputs despread signals at 3τ (sec.) Intervals,
The matched filter 2 is offset by τ (sec.) And outputs a despread signal at an interval of 3 τ (sec.).
Further, the matched filter 3 is further offset by τ (sec.), And outputs a despread signal at an interval of 3 τ (sec.). Thus, by inputting the output despread signal to the information signal rate determiner 823, it is determined that the information rate is 1 / 3τ (bps).

The three-sequence despread signals output from the despread modulator 822 are input to an information demodulator 825, and based on the determined information rate signal 824, BPSK is used.
Demodulated. The demodulated three series of provisionally demodulated signals 1, 2, 3
Is input to the demodulated signal reconstructor 826 and the information rate is reduced to 1 / 3τ by combining the three provisional demodulated signals.
(Bps) information signal is demodulated. This combined demodulated signal is decoded by an information rate signal 824 in a decoder 827.
, And the original information signal is reproduced as the demodulated information signal 828. As described above, by using three types of matched filters 1, 2, and 3, it is possible to demodulate information signals of five different information rates. Similarly, by using k kinds of matched filters, information signals of 2k-1 kinds of information speeds can be received. Here, k is an integer of 2 or more.

As described above, by configuring the spread spectrum transmitter and the spread spectrum receiver in the spread spectrum communication apparatus, an information signal that can take different information rates can be transmitted without transmitting the rate information as a pilot signal. In addition, the information modulator and the information demodulator do not process information at a speed equal to or higher than the maximum information speed that can be obtained, and further, the decoder performs decoding while determining the information speed without performing spectrum decoding. Spread communication can be enabled.

The spread spectrum communication apparatus described above is intended mainly for high-speed spread spectrum communication in an indoor environment, and increases a reference information rate (hereinafter referred to as a reference information rate) or is used outdoors. In this case, a large delayed wave may arrive over one period of the spreading code. This case will be described with reference to FIG. 5, but for simplification of the description, the case of the state 5 shown in FIG. 4 which is least affected by the delay wave will be described as an example. . When there is no influence of the delayed wave, an output is generated in the matched filter at the transmitted interval as in state 5. However, since a multipath actually exists, when the reference information rate is low, a plurality of outputs are generated as shown in A in consideration of the delay wave in FIG. In this case, since the delayed waves are within one period τ (sec.) Of the spreading code, it is possible to separate and combine the respective delayed waves.

Next, when the speed of the reference information signal is high,
Alternatively, FIG. 5 shows a case where a large delayed wave arrives over one period τ (sec.) Of the spreading code due to outdoor use.
Is shown as B when multipath is considered. In this case, the delayed wave arrives over one period τ (sec.) Of the spread code, but the delayed wave is within 3τ (sec.). Can be separated and synthesized because they do not overlap. However, a large delay wave causes one period of the spreading code τ (se
c. In a radio propagation environment where the delay time exceeds the threshold value, the delay wave overlaps with the next information signal in the state 1 to the state 3 shown in FIG. In addition, a large delayed wave is 2τ (sec.).
, The separation becomes impossible even in the state 4, and the separation becomes impossible in all the states when the time exceeds 3τ (sec.). (Hereinafter, the transmission method from state 1 to state 3 shown in FIG. 4 is called simple parallel transmission, and the transmission method in state 4 and state 5 is called retransmission type transmission.)

A method for solving such a problem has been disclosed in the 1996 Spring National Convention A-217 and the like. In this method, in order to enable separation of a delayed wave exceeding one cycle of the spreading code, a PN code is changed every one cycle of the spreading code and circulated every N periods, thereby enabling separation of the delayed wave. Advocates click sign. This makes it possible to separate delayed waves at the time of high-speed transmission. However, when an M sequence that is a general PN code and an orthogonal M sequence are used, even when a 13th-order sequence is used, about 630 types of spreading codes are used. Thus, a sufficient spreading code type cannot be obtained for application to the CDMA system. Also, when a 17th-order sequence is used, 77
About 10 types of spreading codes can be obtained, and the code length is 1
In order to realize a user rate of 10 Mbps, it is necessary to increase the code rate so that it is impractical, or to adopt a sliding correlator that is difficult to output instantaneously instead of a matched filter in terms of circuit scale. Must.

When the number of division multiplexes is increased in order to suppress the code speed, a large number of types of spreading codes are required, and in order to secure enough types of spreading codes for practical use, the circuit scale becomes enormous. High-speed processing will be required. As described above, in order to use not only indoors but also outdoor environments, any PN code may be used, and it is indispensable to use a spreading code suitable for CDMA communication indoors and outdoors. Further, in the retransmission type transmission, since a spreading code is not transmitted in each sequence in each cycle, there is a problem that the detection probability at the time of initial synchronization detection is deteriorated.

Therefore, in the second embodiment of the spread spectrum communication apparatus according to the present invention, the spread code is changed every cycle and circulated every N cycles. The above-mentioned problem is solved by changing the processing after the information signal reconstructing unit according to the environment. In addition, it is possible to change either or both of the number of spreading codes and the cycle at the start of transmission and at the time of data transmission. This allows
Even when a large delay occurs, it can be used, and the initial synchronization probability at the time of reception can be improved. Further, in the second embodiment of the spread spectrum communication apparatus according to the present invention, the spread code is obtained by rearranging a Gold code, an orthogonal Gold code, a bulk code, an orthogonal bulk code, or a two-dimensional shift register or a sequence having a long cycle. A spreading sequence having the same code length and the same spreading code type as the Gold code, or a spreading sequence having the same code length and a larger spreading code type than the M sequence, such as a code of each column of the M plane, which is a two-dimensional linear cyclic code configured. Thus, the present invention is suitable for CDMA communication that can be used by an unspecified number of users in an outdoor environment.

Next, a second embodiment of the spread spectrum communication apparatus of the present invention will be described with reference to FIGS. FIG. 6 is an example of a block diagram showing a configuration of a spread spectrum transmitter in the spread spectrum communication apparatus of the present invention, and FIG. 7 is a circuit diagram showing an example of a configuration of a spread code generator for generating a Gold code. , FIG.
FIG. 9 is a circuit diagram showing an example of a configuration of a spread code generator for generating an orthogonal Gold code, FIG. 9 is a diagram showing a form of a transmission signal for an input information signal, and FIG. 10 is a spread spectrum communication of the present invention. FIG. 2 is an example of a block diagram illustrating a configuration of a spread spectrum receiver in the device.

In FIG. 1, an information signal 111 is input to an information signal reconstructor 114, and the input information signal 11
1 is distributed to k multiple sequences according to the information rate and / or the radio propagation environment. The speed of the information signal in each stream is the same reference information speed. Here, each of the information signals distributed from the sequence 1 to the sequence k is encoded by the encoder 115. Next, in the spread modulator 117, the information signal of each stream is converted by the information rate signal 112 and the initial communication signal 113 into the code rate generated from the spread code generator 116 having changing means for changing the generation timing and cycle ( (Chip rate) is the same, and spectrum spreading is performed by spreading codes PN1 to PNk having the same code length and different from each other. Here, k is a positive integer.

The information signal subjected to the spread spectrum is subjected to DBPSK modulation, QPS
Modulation is performed in units of u bits by a predetermined modulation method based on K modulation, offset QPSK modulation, or the like. Where u is a positive integer and BPSK
The value is 1 in the case of modulation and 2 in the case of QPSK modulation. Note that the encoder 115 may be provided in front of the information signal reconstructor 114 to perform encoding in consideration of the reconstruction of the information signal.

By the way, at the start of transmission, the information signal reconstructing section 114 and the encoding section 11 are designed to improve the initial synchronization probability.
5. The processing of the spreading code generator 116, the information modulation section 118, and the like is different from the processing at the time of data transmission. A signal for making this change is the initial communication signal 113, and the initial communication signal 113 may be an initial communication signal on the side of the spread spectrum receiver provided together with the spread spectrum transmitter. Good. Further, an initial communication signal transmitted together with the information signal may be used, or an initial communication signal generated on the transmitter side. Furthermore, the change at the start of transmission may be performed by a signal obtained by adding the state of radio propagation detected on the receiver side to the initial communication signal. The initial communication signal can also be inserted between successive information signals if it is determined in advance. In this case, the receiving side is changed in the same manner as in the reception standby state.

The spreading code generator 116 rearranges a gold code, an orthogonal gold code, a bulk code, an orthogonal bulk code, or a two-dimensional shift register or a sequence having a long cycle, which have relatively good autocorrelation and cross-correlation. A spreading sequence of the same code length and the same spreading code type as the Gold code, or a spreading sequence having the same code length and a larger spreading code type than the M sequence, such as a code of each sequence on the M plane, which is a two-dimensional linear cyclic code composed of Signs are generated. The circuit shown in FIG. 7 is a general Gold code generation circuit, and as shown in FIG. 7, a modulo-2 circuit for adding two sets of shift registers SR1 and SR2 and predetermined tap outputs of the respective shift registers SR1 and SR2. Adders MOD-1, MOD
-2. These two sets of shift registers SR
1 and SR2, different M-sequence codes are generated, and the generated M-sequence codes are
The gold code is generated by the addition by D-3.

FIG. 8 shows an example of a circuit for generating an orthogonal Gold sequence. This orthogonal Gold sequence generation circuit causes two PN sequence generators 1 and 2 each having a shift register for generating an M sequence to have a data hold function, and a first timing signal (Timing) 1 Data is held for one chip time every 2n cycles. The output sequences of the two PN sequence generators 1 and 2 undergo modulo 2 addition in an exclusive OR (XOR1), and further, a second timing signal (Timing) in an AND circuit (AND1).
According to 2), the data held portion is output. As a result, the Gold code having a code length of 2n-1 is changed to 2
An orthogonal Gold code having a code length of n can be used. Note that the circuits shown in FIGS. 7 and 8 are examples, and the present invention is not limited to this. Also, bulk codes or orthogonal bulk codes generated by using three shift registers instead of two sets have relatively good cross-correlation and auto-correlation, and the number of code types can be further increased. it can.

It is to be noted that in the case of the M sequence and the orthogonal M sequence, 15
Even when the next sequence is used, only 1800 types of sequences can be obtained, and the code length is 32767, which is a long code length. For this reason, when the user rate increases, it is necessary to increase the code rate. Therefore, in order to secure code types sufficient for practical use, the circuit scale becomes enormous and high-speed processing is required. On the other hand, for example, when a Gold code or an orthogonal Gold code is used, 2047 kinds of codes can be generated in an 11th-order sequence. Further, when a bulk code, an orthogonal bulk code, or the like is used, the code length can be used without increasing the code length. The number of possible code types can be increased. As a result, an excellent effect that the circuit scale can be reduced can be obtained.

Further, the spread spectrum transmitter suitable for CDMA can be used both indoors and outdoors. Further, in the second embodiment of the spread spectrum communication apparatus according to the present invention, a plurality of spread codes are used while circulating on one sequence in order to enable separation of delayed waves as described later. Therefore, many spreading codes are required. Also in this case, since the code type of the above-mentioned spreading code is a sufficient number, it is a suitable spreading code.

Next, in the spread spectrum transmitter shown in FIG. 6, the signal form of information signal 111 whose information rate is changed according to the radio propagation environment and the data source is shown in FIG.
FIG. 9A shows the signal form of the transmission signal 119 in FIG.
(B). However, here, for convenience of explanation, when there are three types of spreading codes k (k = 3) and τ (sec.) Is one cycle of the spreading code, it is possible to separate up to 3τ (sec.) Delayed waves. It is a signal form diagram showing that Further, the modulation scheme of the information modulator 118 is BPSK modulation scheme, that is, each information signal ai has 1 (bi
It is assumed that the data of t) is included. Here, i is a positive integer. Further, here, a large delayed wave is 2τ
.About.3.tau. (Sec.), The radio propagation environment mentioned here indicates, for example, fading other than the influence of multipath, interference from other stations, and the like.

State 1 shown in FIG. 9A is the maximum information rate 3 / τ (bp (bp) that the input information signal 111 can take.
s) and / or if the radio propagation environment is very good. However, here, only 18 information signals ai to 18 are shown. When the state is set to 1, the input information signal 111 is sequentially divided into three streams, and the spread modulator 117 spreads each spectrum. That is, when i in the information signal ai is 3m + 1, the signal is distributed to the first stream, and the spreading code PN10, the spreading code PN11, and the spreading code PN12 are circulated and used sequentially. Thus, the information signal ai at the time of i = 3m + 1 is spread. That is, the information signal a1 is based on the spreading code PN10, the information signal a4 is based on the spreading code PN11, the information signal a7 is based on the spreading code PN12, the information signal a10 is based on the spreading code PN10, and the information signal a13 is the spreading code PN1.
1, the information signal a16 is converted by the spreading code PN12 into
Each will be spread spectrum.

When i is 3m + 2, the signal is distributed to the second stream, and the spreading codes PN20, PN21 and PN22 are circulated and used sequentially. Thereby, the information signal ai at the time of i = 3m + 2 is spread. That is, the information signal a2 is based on the spreading code PN20, the information signal a5 is based on the spreading code PN21, the information signal a8 is based on the spreading code PN22, the information signal a11 is based on the spreading code PN20, and the information signal a14 is based on the spreading code PN.
21 allows the information signal a17 to be spread spectrum by the spread code PN22. Furthermore, when i is 3 (m + 1), it is distributed to the third series,
Spreading code PN30, spreading code PN31 and spreading code PN3
2 are circulated and used sequentially. Thus, i = 3
The information signal ai at (m + 1) is spread spectrum. That is, the information signal a3 is the spreading code PN30, the information signal a6 is the spreading code PN31, the information signal a9 is the spreading code PN32, the information signal a12 is the spreading code PN30, and the information signal a15 is the spreading code PN3.
1, the information signal a18 is spread by the spreading code PN32.
Each will be spread spectrum. However,
m is 0 or a positive integer.

The distribution of information signals into the first to third sequences in spread modulator 117 is performed in information signal reconstructor 114. At this time, the information rate on each sequence is 1 / 1 / τ, 3 times the common speed
(Bps). Therefore, the spread transmission signal has a signal form as shown in state 1 in FIG. 9B. As a result, the information signal spread by the same spreading code appears every 3τ (sec.) As shown in FIG.
(Sec.) Or more, the delay waves are separated and combined even in a deteriorated radio propagation environment in which a large delay wave is generated as shown as B when the multipath in FIG. 5 is considered. It becomes possible.

Next, a state 2 shown in FIG. 9A indicates a case where the information speed of the input information signal 111 is 2 / τ (bps) and / or a case where the radio propagation environment is relatively good. Show. However, here, i in the information signal ai
Indicate from 1 to 12. When i in the information signal ai is 2m + 1, the signal is distributed to the first stream, and the spreading code PN10, the spreading code PN11, and the spreading code PN12 are circulated and used sequentially. Thus, the information signal ai at the time of i = 2m + 1 is spread. That is,
The information signal a1 is converted to the information signal a3 by the spreading code PN10.
Is the spread code PN11 and the information signal a5 is the spread code P
By N12, the information signal a7 is spread by the spreading code PN10, the information signal a9 is spread by the spreading code PN11, and the information signal a11 is spread by the spreading code PN12.

When i is 2 (m + 1), the signal is distributed to the second stream, and the spreading codes PN20, PN21 and PN22 are circulated and used sequentially. Thus, the information signal ai at the time of i = 2 (m + 1) is spread. That is, the information signal a2 has the spreading code PN
20, the information signal a4 is spread by the spreading code PN21.
The information signal a6 is converted to the information signal a8 by the spread code PN22.
Are spread by the spread code PN20, the information signal a10 is spread by the spread code PN21, and the information signal a12 is spread by the spread code PN22. However, m is 0 or a positive integer.

In this case, two sequences of the spreading modulator 117 are used, and there is no information signal of the sequence spread by the spreading code PN30 system. The distribution of the information signal into the first sequence and the second sequence in the spread modulator 117 is performed in the information signal reconstructor 114. At that time, the information speed on each stream was set to a common speed of 1/2 times 1 /
τ (bps). Therefore, the spread transmission signal has a signal form as shown in state 2 in FIG. 9B. As a result, the information signal spread by the same spreading code appears every 3τ (sec.) As shown in FIG.
Since the interval is longer than τ (sec.), even in the case of a deteriorated radio propagation environment in which a large delay wave is generated as shown as B in consideration of the multipath in FIG. 5, each delay wave is separated and synthesized. It is possible to do.

State 3 shown in FIG. 9A shows a case where the information rate of the input information signal 111 is 1 / τ (bps) and / or a case where the radio propagation environment is relatively good. However, here, i in the information signal ai is illustrated from 1 to 6. The information signal ai is allotted to the first stream, and the spreading code PN10, the spreading code PN11, and the spreading code PN12 are circulated and used sequentially, and the information signal ai is spread. That is, the information signal a1 is based on the spreading code PN10, the information signal a2 is based on the spreading code PN11, the information signal a3 is based on the spreading code PN12, and the information signal a4 is the spreading code PN1.
Due to 0, the information signal a5 is spread by the spreading code PN11 and the information signal a6 is spread by the spreading code PN12.

In this case, one sequence of the spreading modulator 117 is used, and a spreading code PN20 system and a spreading code PN3
There is no sequence information signal spread by the 0 system. In addition,
The distribution of the information signal into the first stream in the spread modulator 117 is performed in the information signal reconstructor 114. In this case, the information speed on the stream is determined by the input information signal 111.
1 / τ (bps), which is the same as the transmission speed of the transmission speed. Therefore, the transmission signal after spreading has a signal form as in state 3 in FIG. 9B. Thereby, the information signal spread by the same spreading code becomes 3τ as shown in the figure.
(Sec.), And 3τ (sec.
c. ), The delay waves can be separated and combined even in a deteriorated radio propagation environment in which a large delay wave is generated as shown as B when the multipath in FIG. 5 is considered. Becomes

Further, in state 4 shown in FIG. 9A, the information speed of the input information signal 111 is 1 / 2τ (bp
s) and / or the case where the radio propagation environment is relatively poor. Here, i in the information signal ai is shown from 1 to 3. The information signal ai is divided into a first stream, and a spreading code PN10 and a spreading code P
N11 is used sequentially so as to circulate, and 2τ (i−1)
The spectrum is spread every (sec.). Also, the same information signal ai is offset by one cycle of the spreading code and
And the spreading codes PN20 and PN21.
Are sequentially used to circulate, and 2τ (i−1) + τ (s
ec. ) Is spread spectrum.

The distribution of the information signal ai is performed by the information signal reconstructor 114. At this time, the information rate on each stream is twice the information rate 1 / τ (bp
s). Therefore, the transmission signal is the spreading code PN1.
0, the first sequence using the spreading code PN11 and the second sequence using the spreading code PN20 and PN21, the spreading code of each sequence is alternately spread at a period of 2τ (sec.). Further, there is a time difference of τ (sec.) Between the streams. In this case, in each stream, the same information signal is multiplied by a spreading code. At this time, there is no information signal spread by the PN30 system.
Therefore, the signal form is as shown in state 4 in FIG.
As a result, the information signals spread by the same spreading code appear every 4τ (sec.) As shown in the figure, and the interval is 3τ (sec.) Or more. Therefore, the multipath shown in FIG. 5 is considered. Even in the case of a deteriorated radio propagation environment in which a large delayed wave occurs as shown in case B, it is possible to separate and combine the delayed waves. Furthermore, high quality transmission can be performed.

State 5 shown in FIG. 9A indicates a case where the information rate is 1/3 τ (bps) and / or a case where the radio propagation environment is very poor. Here, a case where i in the information signal ai is 1 and 2 is illustrated. In this case, the information signal ai is distributed to the first stream, and 3τ (i−1) (se
c. ) Is spread spectrum. In addition, the same information signal ai is offset by one period of the spreading code and distributed to the second sequence, and 3τ (i−
1) The spectrum is spread every + τ (sec.). Further, the same information signal ai is offset by two periods of the spreading code and distributed to the third sequence, and is spread by the spreading code PN30 every 3τ (i−1) + 2τ (sec.).

In this case, the distribution of the information signal ai is as follows.
This is performed by the information signal reconstructor 114. At this time, the information rate on each stream is tripled as the common information rate 1 /
τ (bps). Therefore, the spreading code PN10
The transmission signal that has been spread by the spread code PN20 and the spread code PN30 is 3 in each sequence.
τ (sec.) period, each of which is τ
(Sec.). Therefore, the transmission signal after spreading has a signal form as in state 5 shown in FIG. 9B. As a result, information signals spread by the same spreading code appear every 3τ (sec.). As a result, the information signals spread by the same spreading code appear every 3τ (sec.) As shown in the figure, and have an interval of 3τ (sec.) Or more.
Even in the case of a degraded radio propagation environment in which a large delay wave shown as B when considering the multipath of FIG.
Each of the delayed waves can be separated and combined. Furthermore, high quality transmission can be performed.

As described above, by using at most three different spreading codes of the same code length (chip rate) and the same code length in one sequence, information of five different information rates can be transmitted. Further, it is possible to transmit a transmission signal capable of separating a delayed wave that does not exceed three periods. Although the above description is for the case where three spreading codes are used, if four or more spreading codes are used, it is possible to transmit information signals at more various information rates. Further, four or more types can be circulated on the same stream according to the delay wave. Furthermore, if the initial communication signal is used, it is easy to change the type of spreading code on the same sequence in accordance with the prediction of the arrival time of a large delayed wave. In addition, it is understood that if the arrival side of the delayed wave is grasped on the receiving side and an appropriate cyclic period is set on the transmitting side, the spread spectrum transmitter is optimal for CDMA communication in high-speed transmission. . Furthermore, although the spreading code is simply circulated, the present invention is not limited to this, and if both the transmitter and the receiver have previously recognized the changing method, there is no need to simply circulate. , Any patrol method may be used.

Next, a configuration example of a spread spectrum receiver according to a second embodiment of the spread spectrum communication apparatus of the present invention will be described with reference to FIG. FIG.
, The received signal 121 is distributed by the despreading modulator 122 from the matched filter 1 composed of mutually different despreading codes having the same code rate and the same code length to the matched filter k on each stream. Then, the output signal subjected to the despreading process is supplied to the information demodulator 126 and the initial communication signal and information signal speed determiner 123.

Then, when the initial reception is performed, the information rate signal 124 and the initial communication signal 125 are output from the initial communication signal / information rate signal determiner 123 and the information demodulator 1
26, the decoder 127 and the demodulated signal reconstructor 128 so that they start operating. As a result, the information demodulator 126 outputs the temporary demodulated signals 1 to k to each stream so that the output signal from the despread modulator 122 is demodulated. These temporary demodulated signals 1 to k are decoded by a decoder 127 for performing a decoding process.
Is supplied to a demodulated signal reconstructor 128 that reconstructs a demodulated signal according to the information rate signal 124. The demodulated signal reconstructor 128 rearranges and combines the signal group supplied from the decoder 127 based on the information rate signal 124, thereby converting the original demodulated information signal to the demodulated information signal 1.
29 is output.

From the viewpoint of reproducing FIG. 9B to FIG. 9A, the initial communication signal and information rate signal judging unit 123 is a matched filter constituting the despread modulator 122. From the output modes of 1 to k, it is determined which of the states 1 to 5 shown in FIG. 9B has been transmitted, and an information demodulator 126, a decoder 127, and Demodulated signal reconstructor 12
It outputs to 8. Each unit to which the information speed signal 124 is supplied is in the supplied state 1 to state 5 shown in FIG. 9B.
A received signal in the same mode as any of the transmitted signals,
By performing reconstruction and synthesis, a demodulated signal having the original information rate as shown in FIG. 9A is reproduced.

Further, it is possible to determine the radio propagation environment such as multipath, fading, interference from other stations, etc. appearing in the output from the matched filter constituting the despread modulator 122. Communication signal 125
And supplied to the information demodulator 126, the decoder 127, and the demodulated information signal reconstructor 128. The information on the wireless propagation environment may be included in the initial communication signal 113 on the transmitting side. Further, at the time of initial transmission or reception standby, by changing the number of spreading sequences to be used and / or one of the spreading periods, the initial synchronization probability can be increased mainly at the time of retransmission-type transmission, and the efficiency can be improved. Good reception. Further, the timing chart showing the operation of the spread spectrum receiver in the above-mentioned states 1 to 5 shown in FIG. 10 is the same as the timing chart shown in FIG.

[0076]

According to the first embodiment of the present invention, as described above, in a transmitter of a spread spectrum communication apparatus, an input information signal is set to a common speed by a speed information signal of an information signal. With different spreading codes of the same code length and the same code length.
Since the signals on each sequence are spread, it is not necessary to add a common control bit for each coding cycle, and it is necessary to perform modulation at the information modulator at a rate higher than the maximum possible information rate. Therefore, the information modulation speed of the information modulator is reduced, and the circuit of the information modulator can be simplified. In addition, it becomes possible to transmit information with high quality when the information speed decreases.

In a spread spectrum receiver,
The received signal is divided into a plurality of streams, and each stream is despread with the same code rate and different despreading codes having the same code length. The speed of the information signal to be demodulated is determined instantaneously, and the demodulated signals on multiple sequences are reconstructed on the same sequence based on the obtained speed information. In addition, since it is not necessary to determine the speed information in the decoder, the information demodulation speed of the information demodulator is reduced, and the decoding time in the decoder is shortened. The circuits of the demodulator and the decoder can be simplified. In addition, it becomes possible to decode information with high quality when the information speed becomes low.

Further, by having both a spread spectrum transmitter and a spread spectrum receiver,
In the information modulator, the information modulation speed can be reduced, and the configuration can be simplified. On the reception side, the information demodulation speed can be reduced in the demodulation modulator, and the configuration can be reduced. It can be simplified. In addition, the information speed judging device can judge the speed information instantaneously, and the judgment of the speed information in the decoder can be dispensed with, and various kinds of high speed information speed information signals can be selectively transmitted. It is possible to simply realize a communication method that can be performed.

Further, in the second embodiment of the present invention, in addition, it is easy to change the communication mode according to the radio propagation environment, and further, it can be used in a propagation environment in which a delayed wave is generated. Thus, it is possible to realize a spread spectrum communication apparatus suitable for CDMA communication that can improve the initial synchronization probability at the time of reception. Also, by using one cycle of the spreading code as a unit, by circulating so that adjacent spreading codes become different spreading codes, it is possible to separate and further combine delayed waves exceeding one cycle of the spreading code. By using a spreading sequence of the same code length and a spreading code type similar to a Gold code, or a spreading sequence with the same code length and a larger spreading code type than the M sequence, it can be used by an unspecified number of users in a propagation environment where delayed waves occur. Possible C
A spread spectrum communication apparatus suitable for DMA communication can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an example of a configuration of a spread spectrum transmitter according to a first embodiment of a spread spectrum communication apparatus of the present invention.

FIG. 2 shows the spread spectrum transmitter shown in FIG.
FIG. 4 is a diagram showing an output timing chart.

FIG. 3 is a block diagram illustrating an example of a configuration of a spread spectrum receiver according to the first embodiment of the spread spectrum communication apparatus of the present invention.

FIG. 4 shows the spread spectrum receiver shown in FIG.
FIG. 4 is a diagram showing an output timing chart.

FIG. 5 is a signal form diagram illustrating a state in which synthesis / removal is possible when a delayed wave occurs in the first embodiment of the spread spectrum communication apparatus of the present invention.

FIG. 6 is a block diagram illustrating an example of a configuration of a spread spectrum transmitter according to a second embodiment of the spread spectrum communication apparatus of the present invention.

FIG. 7 is a diagram illustrating an example of a configuration of a gold code generation circuit used in a spread code generator and the like.

FIG. 8 is a diagram illustrating an example of a configuration of an orthogonal Gold code generation circuit used in a spread code generator and the like.

FIG. 9 is a block diagram of the spread spectrum transmitter shown in FIG. 6;
FIG. 4 is a diagram showing an output timing chart.

FIG. 10 is a block diagram illustrating an example of a configuration of a spread spectrum receiver according to a second embodiment of the spread spectrum communication apparatus of the present invention.

FIG. 11 is a block diagram showing a schematic configuration of a transmitter of the conventional spread spectrum communication system.

FIG. 12 is a block diagram showing a schematic configuration of a conventional spread spectrum communication system receiver.

[Explanation of symbols]

111, 411, 811 Information signal 112, 124, 412, 812, 824 Information rate signal 113, 125 Initial communication signal 114, 814 Information signal reconstructor 115, 813 Encoder 116, 414, 816 Spread code generator 117 , 416, 817 Spreading modulator 118, 415, 815 Information modulator 119, 417, 818 Transmission signal 121, 421, 821 Reception signal 122, 423, 822 Despreading modulator 123 Initial communication signal and information rate signal judging device 126 , 424, 825 Information demodulator 127, 827 Decoder 128, 826 Demodulated signal reconstructor 129, 426, 828 Demodulated information signal 413 Encoding and information signal reconstructor 422 Despread signal generator 425 Decoding and information rate Judgment device 823 Information signal speed judgment device

Claims (11)

[Claims] 1. An information signal reconstructor for dividing an input information signal into a plurality of streams having a predetermined speed according to an information speed signal of the input information signal, and an information signal reconstructor according to the information speed signal. A code generator in which the timing and cycle of spreading code generation are changed, and the respective signals on the plurality of sequences are generated by different spreading codes with the same code rate and the same code length generated by the code generator. A spread spectrum communication device comprising a spread spectrum modulator for spread spectrum and means for adding and transmitting outputs of a plurality of sequences from the spread modulator. 2. A means for distributing a spread spectrum received signal to a plurality of streams, and a despreading process provided by each of the plurality of streams and having a same code rate and a same code length and different spreading codes. A plurality of matched filters, an information rate determiner for determining a rate of an information signal to be demodulated based on output information of the matched filter, and an information rate obtained from the information rate determiner. A spread spectrum communication apparatus comprising a demodulated signal reconstructor for reconstructing demodulated demodulated signals on the plurality of streams into an original information signal. 3. An information signal reconstructor for allocating the input information signal to a plurality of streams having a predetermined speed according to the information speed signal of the input information signal, and in accordance with the information speed signal. A code generator in which the timing and cycle of spreading code generation are changed, and the respective signals on the plurality of sequences are generated by different spreading codes with the same code rate and the same code length generated by the code generator. Transmitting means having a spread spectrum modulator for spread spectrum and means for adding and transmitting outputs of a plurality of sequences from the spread modulator, and means for distributing a spread spectrum received signal to a plurality of sequences And a plurality of matched filters provided in each of the plurality of streams and configured to perform despreading processing with different spreading codes having the same code length and the same code length, and the matching filter. An information rate determiner for determining the rate of the information signal to be demodulated based on the output information of the filter, and demodulated signals on the plurality of streams demodulated according to the information rate obtained from the information rate determiner. A spread spectrum communication device, comprising: a receiving unit having a demodulation signal reconstructor for reconstructing an original information signal. 4. An information transmission rate of an input information signal,
Depending on the radio propagation environment and / or
An information signal reconstructor that distributes the input information signal into a plurality of streams, a code generator having a means for changing the timing and period of spreading code generation, and the same code rate generated by the code generator. Spreading modulators that spread spectrum each signal on the plurality of sequences by using spreading codes having different code lengths, and transmission means that adds and transmits the outputs of the plurality of sequences output from the spreading modulators. A spread spectrum communication device comprising: 5. The method according to claim 4, wherein at least one of the number of sequences and the period of the spread code to be used can be changed between the initial transmission and the transmission of the input information thereafter.
A spread-spectrum communication device as described. 6. A spreading process is performed by circulating a spreading code group so that at least adjacent spreading codes are different in units of one cycle of the spreading code on each sequence of the plurality of sequences. 5. The code generator according to claim 4, wherein the code generator generates a spreading sequence of the same code length and a spreading code type of about the Gold code, or a spreading sequence of the same code length and a larger number of spreading code types than the M sequence. 6. The spread spectrum communication apparatus according to 5. 7. A means for distributing a spread-spectrum received signal into a plurality of sequences, and despreading the plurality of sequences configured to perform despreading processing using mutually different despreading codes having the same code rate and the same code length. A matched filter provided for each, an information rate determiner for determining a speed of an information signal to be demodulated based on output information of the matched filter, and a demodulated signal according to the information rate obtained from the information rate determiner. A demodulated signal reconstructor for reconstructing the demodulated signals on the plurality of sequences into an original information signal. A spread spectrum communication apparatus characterized in that both or one of them is changed. 8. When data is received, a despreading process is performed by circulating a spread code group on each of the plurality of sequences so that at least adjacent spread codes are different in units of one cycle of the spread code. Wherein the despreading code at this time is a spreading sequence of the same code length and a spreading code type of about the Gold code, or a spreading sequence of the same code length and having more spreading code types than the M sequence. Item 9. A spread spectrum communication device according to item 7. 9. An information transmission rate of an input information signal,
Depending on the radio propagation environment and / or
An information signal reconstructor that distributes the input information signal into a plurality of streams, a code generator that has means for changing the timing and period of spreading code generation, and the same code rate generated by the code generator. A spread modulator that spreads each signal on each of the plurality of sequences by using spread codes having different code lengths, and a transmission unit that adds and transmits the outputs of the plurality of sequences output from the spread modulator. A means for distributing the spread spectrum received signal to a plurality of sequences, and means provided for each of the plurality of sequences configured to perform despreading processing by mutually different despreading codes having the same code rate and the same code length. A matched filter, an information rate determiner that determines the rate of the information signal to be demodulated based on the output information of the matched filter, and an information rate that is obtained from the information rate determiner. And a demodulated signal reconstructor for reconstructing the demodulated signals on the plurality of sequences into the original information signal, and the sequence of the despreading code to be used during reception standby and data reception. It is characterized in that it is provided with a receiving side changing means for changing either or both of the number and the period, and that the original information signal is reproduced from the spread spectrum signal transmitted from the transmitting side. Spread spectrum communication device. 10. A transmitting-side changing means for changing at least one of a sequence number and a cycle of a spreading code to be used at the time of initial transmission and at the time of transmission of the input information thereafter. The spread spectrum communication apparatus according to claim 9, wherein: 11. The code generator according to claim 1, wherein the code generator generates a spreading sequence of the same code length and a spreading code type of about the Gold code, or a spreading sequence of the same code length and a larger spreading code type than the M sequence. In the spreading modulator, on the plurality of sequences, the spreading code group generated in the code generator is circulated so that at least adjacent spreading codes are different at least in units of one cycle of the spreading code, thereby performing spreading processing and despreading. 11. The spread spectrum communication apparatus according to claim 9, wherein processing is performed.