JP2016072911A - Data communication device, data communication method, transmitter, and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a code spread system that enables RAKE reception to receive a signal through multi-paths while improving burst errors.SOLUTION: A data communication device 10 for converting a one-bit transmission signal into L pieces of code data and transmitting them comprises a spread processing unit 100 for transmitting a spread signal in which the L pieces of code data are arranged per space of L+1. An inverse spread processing unit 200 receives the spread signal and outputs an inverse spread signal obtained by decoding the L pieces of code data to a RAKE reception unit 300.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a data communication device, and more particularly to a data communication device, a data communication method, a transmitter, and a receiver that perform communication by a code spread communication method.

  As one of communication methods, a code spread communication method is known in which an n-bit transmission signal is converted into a code consisting of L bits and transmitted. The code spread communication method is generally used in a transmission line with a lot of noise. In the code spread communication system, the transmission side transmits a signal (spread signal) converted into a code consisting of L bits. On the other hand, the reception side restores the original transmission signal by detecting the correlation of the received spread signal. This processing on the receiving side is called despreading processing.

  Patent Document 2 describes a technique for improving a burst error of a code spread communication system.

  On the other hand, the RAKE reception method is used as one of fading and multipath countermeasures of the code spread communication method. RAKE means a rake and is a reception method that improves reception accuracy by collecting signals scattered in time on a transmission path.

JP-A-63-184427 (FIG. 2)

  FIG. 5 is an arrangement diagram of spread signals generated in Patent Document 1, specifically, an arrangement diagram of spread signals when m transmission signals are spread with a spread code having a code length L. The spread signal 1 is a spread signal of the transmission signal D1, and is arranged at intervals of m-1 in the order of D1-1, D1-2, ..., D1-L in order from the first spread code. Similarly, the transmission signal D2 to the transmission signal Dm are arranged at an interval of m-1. The m transmission signals are spread and arranged at intervals of m−1 symbols. The spread signal spread at an interval of m−1 symbols is D1-1 to D1-L for the first transmission signal, D2-1 to D2-L for the second transmission signal, and Dm− for the mth transmission signal. 1 to Dm-3 are arranged with a delay of one symbol at a time. Finally, the m transmission signals are arranged in a spread signal 4 sequence.

  With regard to the spread signal arrangement, paying attention to the spreading code number, the first code is arranged in m symbols continuously, the second code is arranged in m symbols continuously, and arranged in the same relationship up to the Lth. It can be understood from FIG. This means that if a delay due to multipath occurs even for one symbol, the delayed signal interferes with a signal obtained by spreading the next transmission signal.

  That is, the technique of Patent Document 1 can improve burst errors, but it is extremely difficult to adopt the RAKE reception method in a multipath environment.

  The present invention has been made in order to solve the above-described problem, and in a code spread communication system, data communication that can employ RAKE reception for receiving a multipath signal while improving a burst error. An object is to provide an apparatus, a data communication method, a transmitter, and a receiver.

  The data communication apparatus of the present invention is a data communication apparatus that converts a 1-bit transmission signal into L code data and transmits the code signal, and transmits a spread signal in which L code data are arranged at intervals L + 1. A diffusion processing means is provided.

  The data communication method of the present invention is a data communication method for transmitting a 1-bit transmission signal after converting it into L code data, and transmits a spread signal in which L code data are arranged at intervals L + 1. A diffusion processing step is provided.

  The transmitter according to the present invention is a transmitter that converts a 1-bit transmission signal into L code data and transmits the spread signal, and performs spreading processing for transmitting a spread signal in which L code data are arranged at intervals L + 1. Means.

  The receiver of the present invention receives a spread signal in which L pieces of code data are arranged at intervals L + 1 from a transmitter that converts a 1-bit transmission signal into L pieces of code data, and transmits L pieces of code data. Despreading processing means for outputting a despread signal in which the code data is combined is provided.

  According to the present invention, it is possible to employ RAKE reception for receiving a multipath signal while improving burst errors in a code spread communication system.

It is a block diagram which shows the structural example of the data communication apparatus which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the switch switching operation | movement in the spreading | diffusion processing part shown in FIG. It is a figure which shows the example of the spreading | diffusion signal produced | generated by the spreading | diffusion process part shown in FIG. It is a block diagram which shows the structural example of the de-spreading process part which concerns on the 2nd Embodiment of this invention. FIG. 10 is a layout diagram of spread signals generated in Patent Document 1.

[First Embodiment]
(Description of configuration)
FIG. 1 is a block diagram showing a configuration example of a data communication apparatus 10 according to the first embodiment of the present invention. In the following description, L represents a spreading code length.

  The data communication apparatus 10 includes a diffusion processing unit 100 (diffusion processing unit), a despreading processing unit 200 (despreading processing unit), and a RAKE receiving unit 300 (RAKE receiving unit).

  The spread processing unit 100 includes a spread code 101, a register 102, a multiplier 103, and a switch 104.

  The spreading code 101 is a code such as a PN (Pseudo Noise) code, for example. The register 102 is a register having a length of 1. The multiplier 103 multiplies the transmission signal or the transmission signal delayed by the register 102 by the spreading code 101. The switch 104 switches the result of multiplication and outputs a spread signal (Tx). The spread signal (Rx) is a signal obtained by converting the spread signal (Tx) to the baseband frequency after passing through the transmission circuit, the transmission path, and the reception circuit.

  The despreading processing unit 200 includes a spreading code 201, a shift register 202, a multiplier 203, and an adder 204. As the spreading code 201, the same spreading code as the spreading code 101 used in the spreading processing unit 100 is used. The shift register 202 is a length L shift register. The multiplier 203 multiplies the spread code 201 by the spread signal (Rx) or the spread signal (Rx) signal delayed by the shift register 202. The adder 204 adds all the results calculated by the L multipliers 203.

The RAKE receiving unit 300 receives the despread signal output from the despreading processing unit 200, converts it into a received signal, and outputs it.
(Description of operation)
Hereinafter, the operation of the data communication apparatus 10 will be described with reference to FIGS. In FIG. 1, the frequency of the transmission signal is represented by F. The register 102 operates at the frequency F. The switch 104 operates at a frequency F × L.

  FIG. 2 is a diagram for explaining the switching operation of the switch 104 in the diffusion processing unit 100. Specifically, FIG. 2 shows the relationship between the transmission signal and the terminal number selected in the switch 104.

  The switch 104 first selects the terminal number 1 at the timing when the transmission signal is input to the diffusion processing unit 100. Thereafter, the switch 104 switches the terminals in the order of terminal number 2, terminal number 3,.

  FIG. 3 is a diagram illustrating an example of a spread signal generated by the spread processing unit 100. Specifically, FIG. 3 shows the relationship between the transmission signal and the spread signal when L = 7 {−1, 1, −1, −1, 1, 1, 1}. The diffusion processing unit 100 operates in the same manner as an interpolation filter that inserts L = 7 zeros. That is, when an impulse that changes at the frequency F is input, the impulse response is a signal that changes at a frequency of F × L by interpolating L = 7 zeros.

  The despreading processing unit 200 serves as a matched filter for diffusion processing. In the despreading processing unit 200, the multiplier 203 multiplies the spread signal (Rx) or the spread signal (Rx) signal delayed by the shift register 202 by the spread code 201. The adder 204 adds all the results calculated by the L multipliers 203 and outputs a despread signal.

  The RAKE receiving unit 300 receives the despread signal output from the despreading processing unit 200, converts it into a received signal, and outputs it.

In the first embodiment described above, the spread time length is expanded by interpolating L = 7 zeros in the transmission signal. Further, since burst noise is distributed to a plurality of despread signals at the time of despreading, the influence of noise is reduced.
(Explanation of effect)
In the first embodiment described above, the diffusion time length is expanded as shown in FIG. Therefore, even if L / 2 continuous burst errors occur in the spread signal, the continuous burst errors are spread to a plurality of received signals during despreading. Therefore, the first embodiment can avoid a specific received signal from being erroneous due to burst noise.

  Furthermore, in the first embodiment described above, in the case of an ideal transmission path without multipath, a signal having a high correlation is output as a despread signal every L time similarly to a general code spread communication system. The That is, in the case of a transmission path with multipath, a signal that appears from the despread signal at time L-1 can be regarded as a multipath component. Therefore, the first embodiment can employ the RAKE reception method in a multipath environment, although the spreading time length is extended.

  In summary, the first embodiment can employ RAKE reception for receiving a multipath signal while improving burst errors.

  1 illustrates a state in which the data communication device 10 includes all of the spread processing unit 100, the despreading processing unit 200, and the RAKE receiving unit 300. However, the data communication device 10 includes only the spread processing unit 100. Even if it is comprised by, the effect equivalent to the effect mentioned above is achieved.

Further, in FIG. 1, a transmitter having only the spread processing unit 100 is referred to as a “transmitter”, and a receiver having only the despreading processing unit 200 (the RAKE receiving unit 300 may be included in some cases) is “received”. Machine ".
[Second Embodiment]
FIG. 4 is a block diagram illustrating a configuration example of the despreading processing unit 301 according to the second embodiment of the present invention.

  The despreading processing unit 301 includes N−1 registers 302 and N matched filters 304. Matched filter 304 includes downsampling 400, register 402, spreading code 404, multiplier 406, and adder 408.

  The register 302 gives a delay of frequency F × L to the input spread signal (Rx).

  The downsampling 400 performs decimation of a spread signal having a frequency F × L and converts it into a signal having a frequency F. The register 302 is a register having a length of 1.

  The despread signals # 1 to #N, which are the outputs of the matched filter 304, are multipath components having a frequency F × L, and are equivalent to the signal for N hours of the despread signal in FIG.

  By configuring as in the second embodiment described above, the same effect as in the first embodiment can be obtained.

  As mentioned above, although this invention was demonstrated using each embodiment, the technical scope of this invention is not limited to description of said each embodiment. It is obvious to those skilled in the art that various modifications or improvements can be added to the above embodiments. Therefore, it is needless to say that embodiments with such changes or improvements are also included in the technical scope of the present invention. The numerical values and names of the components used in the embodiments described above are illustrative and can be changed as appropriate.

DESCRIPTION OF SYMBOLS 10 Data communication apparatus 100 Spreading process part 101 Spreading code 102 Register 103 Multiplier 104 Switch 200 Despreading process part 201 Spreading code 202 Shift register 203 Multiplier 204 Adder 300 RAKE receiving part 301 Despreading process part 302 Register 304 Matched filter 400 Downsampling 402 Register 404 Spreading code 406 Multiplier 408 Adder

Claims (9)

A data communication apparatus that converts a 1-bit transmission signal into L pieces of code data and transmits the code data,
A data communication apparatus comprising: a spread processing means for transmitting a spread signal in which L pieces of code data are arranged at intervals of L + 1.   2. The data communication apparatus according to claim 1, further comprising despreading processing means for receiving the spread signal and outputting a despread signal obtained by combining the L pieces of code data.   3. The data communication apparatus according to claim 2, further comprising RAKE receiving means for inputting the despread signal, converting the despread signal into a received signal, and outputting the received signal. A data communication method for converting a 1-bit transmission signal into L pieces of code data and transmitting the code data,
A data communication method comprising: a spread processing step of transmitting a spread signal in which L pieces of code data are arranged at intervals of L + 1.   5. The data communication method according to claim 4, further comprising a despreading process step of receiving the spread signal and outputting a despread signal obtained by combining the L pieces of code data.   6. The data communication method according to claim 5, further comprising a RAKE receiving step of inputting the despread signal, converting it into a received signal and outputting the received signal. A transmitter that converts a 1-bit transmission signal into L pieces of code data and transmits the data.
A transmitter comprising: spread processing means for transmitting a spread signal in which L pieces of code data are arranged at intervals of L + 1.   A spread signal in which L pieces of code data are arranged at intervals L + 1 is received from a transmitter which converts a 1-bit transmission signal into L pieces of code data, and is an inverse combination of L pieces of code data. A receiver comprising despreading processing means for outputting a spread signal.   9. The receiver according to claim 8, further comprising RAKE receiving means for inputting the despread signal, converting the despread signal into a received signal, and outputting the received signal.

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