JP3789013B2 - Communication apparatus and communication method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication device and a communication method.
[0002]
[Prior art]
Conventionally, under the condition that the width of the transmission band is constant, it has been possible to realize high-speed data transmission without lowering the spreading factor of spread modulation by using a multiplex communication method by code division.
[0003]
The spread spectrum communication method using the direct spread method uses a spread code sequence such as a pseudo noise code (PN code) from the baseband signal of a digital signal that is normally transmitted, and has a very wide bandwidth compared to the original data. Generate a baseband signal. Further, modulation such as PSK (phase shift keying), FSK (frequency shift keying), etc. is performed, converted into an RF (radio frequency) signal and transmitted. On the receiving side, despreading that correlates with the received signal is performed using the same spreading code as that on the transmitting side, and the received signal is converted into a narrowband signal having a bandwidth corresponding to the original data. Subsequently, normal data demodulation is performed to reproduce the original data.
[0004]
In this way, in the spread spectrum communication method, the transmission bandwidth is extremely wide compared to the information bandwidth, so that under a condition where the transmission bandwidth is constant, only a very low transmission rate can be realized compared to the normal narrowband modulation method. It becomes. In order to solve such a problem, there is a method called code division multiplexing. In this method, a high-speed information signal is converted into low-speed parallel data, spread-modulated with different spreading code sequences, added, and then converted into an RF signal for transmission.
[0005]
As a result, high-speed data transmission can be performed without reducing the spreading factor of the spread modulation even under the condition that the transmission bandwidth is constant.
[0006]
FIG. 5 is a block diagram showing a configuration of a transmission unit of a conventional spread spectrum communication apparatus using the above method.
[0007]
In FIG. 5, 501 is a serial-parallel converter, 502-1 to n are multipliers, 503 is a spread code generator, 504 is an adder, 505 is a radio frequency (RF) converter for converting to a transmission frequency signal, Reference numeral 506 denotes a transmission antenna.
[0008]
The operation of the transmission unit of the spread spectrum communication apparatus configured as described above will be described below.
[0009]
The input data is converted into n parallel data by the serial-parallel converter 501. Each of the converted data is multiplied by n different spread code outputs from the spread code generator 503 in n multipliers 502-1 to 502-1 to be converted into n-channel wideband spread signals. Next, the outputs of the multipliers are added by the adder 504 and output to the RF converter 505. The baseband wideband spread signal added by the RF converter 505 is converted into a transmission frequency signal having an appropriate center frequency and transmitted from the transmission antenna 506.
[0010]
FIG. 6 is a block diagram showing a configuration of a receiving unit of a conventional spread spectrum communication apparatus.
[0011]
In FIG. 6, 601 is a receiving antenna, 602 is a radio frequency (RF) converter, 603-1 to n are correlators, 604-1 to n are spread code generators, 605-1 to n are synchronization circuits, and 606- 1 to n are demodulators, and 607 is a parallel-serial converter.
[0012]
The operation of the receiving unit of the spread spectrum communication apparatus configured as described above will be described below.
[0013]
The transmission signal received by the reception antenna 601 is appropriately filtered and amplified by the RF converter 602 and converted into an intermediate frequency signal. The intermediate frequency signal is distributed to channels corresponding to n spread codes connected in parallel. In each channel, the correlators 603-1 to 60-n detect the correlation between the outputs of the spread code generators 604-1 to 60-n corresponding to the respective channels, and the synchronization circuits 605-1 to 60-n establish synchronization for each channel. Then, the code phases and clocks of the respective spread code generators 805-1 to 80-n are matched, and the demodulator 606-1 to 606-1n demodulates and reproduces data. Further, the reproduced data is converted into serial data by a parallel / serial converter 607 and is reproduced as original data.
[0014]
[Problems to be solved by the invention]
However, the conventional spread spectrum communication apparatus described above has the following drawbacks.
[0015]
For example, as code division is performed and the number of channels is increased, a phenomenon called multipath fading is more likely to occur. This phenomenon is a phenomenon in which the level of the synthesized wave is lowered because the phase of the direct wave and the reflected wave is different, which causes a drawback that an error due to communication failure or communication interruption is likely to occur.
[0016]
SUMMARY An advantage of some aspects of the invention is that it provides a communication device and a communication method capable of performing good data transmission.
[0017]
[Means for Solving the Problems]
The communication apparatus according to the present invention includes , for example, an imaging unit that generates an image signal using a lens and an imaging device, and a control signal indicating the state of the imaging unit using one or more spreading codes, or the imaging unit. a modulating means for modulating the generated image signals, and transmitting means for transmitting the control signal or the images signals modulated by the modulation means, said modulation means is used to modulate the control signal spreading The number of codes is smaller than the number of spreading codes used for modulating the image signal.
[0018]
The communication method according to the present invention is , for example, a communication method of a communication apparatus having an image pickup unit that generates an image signal using a lens and an image pickup device, and the state of the image pickup unit using one or more spreading codes a control signal or modulation step of modulating the image signal generated by the imaging device showing a, and a transmission step of transmitting the control signal or the images signals modulated by the modulation step, the modulation process, The number of spreading codes used for modulating the control signal is made smaller than the number of spreading codes used for modulating the image signal.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail by taking a wireless communication apparatus using a spread spectrum communication system as an example.
[0028]
(First embodiment)
1 and 2 are block diagrams showing a wireless communication apparatus A and a wireless communication apparatus B using a spread spectrum communication system according to a first embodiment of the present invention. The wireless communication apparatus A in FIG. 1 and the wireless communication apparatus B in FIG. 2 perform wireless transmission in both directions.
[0029]
In FIG. 1, 101 is a lens that captures a subject, 102 is a drive circuit that changes the magnification of the lens, 103 is an image sensor that converts the captured subject into an image signal, and 104 samples and holds the image signal to obtain an appropriate signal level. CDS / AGC, 105 is a digital signal processing circuit for A / D converting the analog image signal from the CDS / AGC and performing digital signal processing, 106 is an image compression circuit / frame dropping circuit, 107 is a digital image signal A communication protocol unit that performs control for conversion to digital image data suitable for transmission using a spread spectrum communication system, 108 is a microcomputer, 109 is a spread spectrum transmission / reception unit, 110 is an antenna, and 111 is the importance of data. An importance level discrimination circuit for discrimination, 112 is an importance level discrimination circuit Multiplex number control unit for changing the number of multiplexed transmission data in accordance with the output of 11, 113 denotes a setting circuit for setting the importance the user according to the data.
[0030]
Next, in FIG. 2, 201 is an antenna, 202 is a spread spectrum transmission / reception unit for detecting a transmission signal received from the antenna 201, 203 is an image expansion circuit for expanding image signal data, and 204 is a digital signal for detecting the detected signal. A communication protocol unit for controlling the conversion to, an NTSC encoder 205 for outputting a digital image signal to the monitor 206, a monitor 206, a zoom key 207 for controlling the zoom of the lens 101, a microcomputer 208, and an important data 209 An importance level discriminating circuit for discriminating the degree, 210 a multiplexing number control unit that changes the number of multiplexed transmission data according to the output of the importance level discriminating circuit 209, and 211 a setting circuit for the user to set the importance level according to the data Show.
[0031]
Below, operation | movement of the radio | wireless communication apparatus A and the radio | wireless communication apparatus B which were comprised as mentioned above is demonstrated.
[0032]
The subject captured by the lens 101 of the wireless communication apparatus A is converted into a digital image signal through the image sensor 103, the CDS / AGS 104, and the digital signal processing circuit 105. The digital image signal is subjected to image compression or frame reduction processing by the image compression circuit / frame dropping circuit 106 in order to reduce the amount of data, and the communication protocol unit 107 converts the digital image data into a spread spectrum communication system. It is converted into digital image data suitable for transmission. The digital image data is input to the spread spectrum transmission / reception unit 109, converted into a transmission form of the spread spectrum communication system, and wirelessly transmitted through the antenna 110.
[0033]
The data transmitted from the wireless communication device A is an image signal, an audio signal, a control signal, etc., and depending on the data content, it is desired to transmit reliably without error or to transmit more data even if some errors occur. There is a case. In order to realize good data transmission based on such various situations, it is necessary to set the importance according to the content and type of transmission data.
[0034]
For the importance, a value set in advance according to the content or type of transmission data or a value arbitrarily set by the user using the setting circuit 113 is used. For example, when a reliable transmission such as a control signal is required, the importance is set high. In such a case, the content or type of the data to be transmitted is first determined by the microcomputer 108, and the determination result is output to the importance determination circuit 111. The importance determination circuit 111 determines the importance corresponding to the transmission data based on a value set in advance or a value arbitrarily set by the user using the setting circuit 113, and a multiplexing number control unit according to the determination result. 112 is controlled.
[0035]
Note that the control signal transmitted from the above-described wireless communication device A is transmitted as a signal for controlling communication between the wireless communication device A and the wireless communication device B, and a signal indicating the state of the lens 101 that is the imaging unit. For example, a signal indicating data-specific information such as data content, type, and compression rate. In addition, since the control signal is desired to be transmitted reliably unlike the image signal and the audio signal, the multiplex number control is performed so that the data with high importance is transmitted with a smaller multiplex number than the image signal and the audio signal. Controlled by unit 210.
[0036]
The radio wave received by the antenna 201 of the wireless communication apparatus B is despread modulated by the spread spectrum transmission / reception unit 202 and converted into digital image data by the communication protocol unit 204. Since the digital image data is compressed, it is expanded by the image expansion circuit 203 and output to the monitor 206 through the NTSC encoder 205. That is, the video signal and audio signal captured by the lens 101 of the wireless communication apparatus A in FIG. 1 are transmitted by the spread spectrum communication method, received by the wireless communication apparatus B, and then output by the monitor 206.
[0037]
The wireless communication device B not only receives information signals such as video signals or audio signals from the wireless communication device A, but also wirelessly communicates control signals for controlling the operation of the imaging unit of the wireless communication device A such as zoom / focus. To device A.
[0038]
When the photographer performs zooming with the tele / wide zoom key 207, the control signal is input to the spread spectrum transmission / reception unit 202 via the microcomputer 208 and the communication protocol unit 204. The control signal spread-modulated by the spread spectrum transmission / reception unit 202 is transmitted from the antenna 201 to the wireless communication apparatus A. The transmitted control signal is received by the antenna 110 of the wireless communication apparatus A, despread modulated by the spread spectrum transmission / reception unit 109, and input to the microcomputer 108 via the communication protocol unit 107. Further, the control signal output from the microcomputer 108 is sent to the drive circuit 102 to drive the zoom of the lens 101 so that the photographer wants to control it.
[0039]
That is, the above description shows that it is possible to drive the zoom of the lens 101 by transmitting a control signal (for example, a zooming signal) from the wireless communication apparatus B to the wireless communication apparatus A. That is, if the wireless communication device B is used, the camera function of the wireless communication device A can be controlled from a remote place.
[0040]
In the present embodiment, as in the case of the wireless communication device A, when transmitting an information signal from the wireless communication device B, the transmitted data is a value set in advance by the importance determination circuit 209 or the user by the setting circuit 211. It is possible to determine the degree of importance based on an arbitrarily set value, and to control the multiplex number control unit 210 according to the determination result. Here, since the control signal is desired to be transmitted reliably, unlike the image signal and the audio signal, it is determined as highly important data, and the multiplex number control is performed so that the control signal is transmitted with a multiplex number smaller than at least the image signal. Controlled by the unit 210.
[0041]
3 is a detailed block diagram of the transmission unit of the spread spectrum transmission / reception units 109 and 202, and FIG. 4 is a detailed block diagram of the reception unit of the spread spectrum transmission / reception units 109 and 202.
[0042]
In FIG. 3, reference numeral 301 denotes a serial-parallel converter that divides input data input in series in predetermined block units into m parallel data and converts the data into n parallel data including m parallel data, and 302 denotes a multiplex. A parallel number control circuit 303 that calculates the division multiplexing number m based on the outputs from the number control units 112 and 210 and controls the series-parallel converter 301, the selection signal generation circuit 306, and the gain control circuit 309 according to the calculation result. A spreading code generator for generating n different spreading codes and a synchronization spreading code, 304-1 to n are multipliers for multiplying each of n parallel data and n spreading codes, and 305 is a multiplication A switch for selecting (n-1) outputs of the units 304-2 to 30-n, a selection signal generating circuit 306 for controlling the switch 305, and a reference numeral 307 for the synchronization dedicated spreading code PN0 and the outputs of the multipliers 304-1 to 30-n. 308 is a radio frequency (RF) converter for converting the output of the adder 307 into a radio transmission frequency, and 309 controls the transmission output of the RF converter 308 according to the code division multiplexing number m. A gain control circuit 310 is an antenna.
[0043]
In FIG. 4, 401 is an antenna, 402 is a radio frequency (RF) converter, 403 is a synchronization circuit that supplements and maintains synchronization with a spreading code and a clock on the transmission side, and 404 is a code input by the synchronization circuit 403. A spreading code generator for generating the same spreading code as the spreading code on the transmission side by the synchronization and clock signals; 405, a carrier recovery circuit for recovering a carrier signal by a carrier recovery spreading code output from the spreading code generator 404; 406 is a despreading modulator that performs despreading modulation processing on m parallel data subjected to spread modulation, 407 is a channel number detection circuit that detects the number of channels based on the output of the despreading modulator 406, and 408 is channel number detection. A parallel number control circuit that controls the serial-to-parallel converter 409 based on the output of the circuit 407. 409 corresponds to the output of the parallel number control circuit 408. Selects the m parallel data from the n pieces of parallel data output from the despreading modulator 406, a parallel to serial converter for converting a serial data string.
[0044]
Hereinafter, operations of the transmission unit and the reception unit of the spread spectrum transmission / reception units 109 and 202 configured as described above will be described.
[0045]
In FIG. 3, the parallel number control circuit 302 divides the multiplex number output from the multiplex number control units 112 and 210 and determines the code division multiplex number m of the input data based on the control signal. The serial / parallel converter 301 divides input data input in series in predetermined block units into m parallel data, and converts the data into n parallel data including m parallel data.
[0046]
The spreading code generator 303 generates (n + 1) spreading codes PN0 to PNn having the same code period and different from each other. Of these, PN0 is dedicated to synchronization and carrier reproduction and is directly input to the adder 307. Further, the remaining n spread code sequences PN0 to PNn are subjected to spread modulation by n parallel data output from the serial-parallel converter 301 and n multipliers 304-1 to n.
[0047]
Of the n spread-modulated data, only m is necessary, and therefore the selection signal generation circuit 306 performs selection control through the switch 305. The selected m signals are input to the adder 307 together with the synchronization dedicated signal PN0.
[0048]
The adder 301 linearly adds the input (m + 1) signals (m spread-modulated signals and the synchronization dedicated signal PN0), outputs a baseband signal, and inputs the baseband signal to the RF converter 308. The RF converter 308 converts the baseband signal into a high-frequency signal having an appropriate center frequency and transmits the signal through the antenna 310.
[0049]
In FIG. 4, a transmission signal received by an antenna 401 is appropriately filtered and amplified by an RF converter 402, converted into an appropriate intermediate frequency band signal, and output. The received signal is input to the synchronization circuit 403, which establishes spreading code synchronization and clock synchronization with respect to the transmission signal, and outputs the code synchronization and clock signal to the spreading code generator 404.
[0050]
After synchronization is established by the synchronization circuit 403, the spreading code generator 404 generates a plurality of spreading codes whose clocks and spreading code phases coincide with the plurality of spreading codes on the transmission side. Of the plurality of spreading codes, a synchronization spreading code PN0 is input to the carrier recovery circuit 405. The carrier regeneration circuit 405 regenerates the carrier wave in the intermediate frequency band that is the output of the RF converter 402 by using the synchronization dedicated spreading code PN0.
[0051]
The regenerated carrier wave is input to the despreading modulator 406 together with the output of the RF converter 402 to generate a baseband signal. The baseband signal is despread for each spreading code by n spreading codes PN1 to PNn generated from the spreading code generator 404 to obtain n parallel data. In addition, the despreading modulator 406 stores a correlation value of a product of the received signal for one period of each of the n spreading codes in the channel number detection circuit 407.
[0052]
When the absolute value of the correlation value of each channel is equal to or less than a certain value, the channel number detection circuit 407 determines that the channel is not transmitting. That is, the number of channels whose correlation value is greater than or equal to a certain value is counted, and this number is output to the parallel number control circuit 408 as a multiplexing number. The parallel number control circuit 408 controls the parallel number of the parallel-serial converter 409 according to the input multiplex number. The parallel-serial converter 409 sets the parallel number by the parallel number control circuit 408, converts only m effective data among the n parallel data demodulated by the despreading modulator 406 into serial data, and reproduces the data. Output as.
[0053]
As described above, in the first embodiment of the present invention, the code division multiplexing number can be controlled according to the content of the information signal to be transmitted. For example, it is possible to perform good wireless communication resistant to multipath fading by setting to transmit on multiple channels when transmitting an image signal and transmitting at least a channel smaller than the image signal when transmitting a control signal. it can.
[0054]
(Second embodiment)
7 and 8 are block diagrams showing a wireless communication apparatus A and a wireless communication apparatus B using the spread spectrum communication system according to the second embodiment of the present invention. The wireless communication device A of FIG. 7 and the wireless communication device B of FIG. 8 perform wireless transmission in both directions.
[0055]
In the following, the same reference numerals are used for members that are the same as or equivalent to those of the first embodiment, and a detailed description thereof is omitted.
[0056]
In FIG. 7, reference numeral 701 denotes a multiplexing number selection unit, and 702 denotes a multiplexing number control unit.
[0057]
In FIG. 8, reference numeral 801 denotes a multiplex number selection unit, and 802 denotes a multiplex number control unit.
[0058]
Below, operation | movement of the radio | wireless communication apparatus A and the radio | wireless communication apparatus B which were comprised as mentioned above is demonstrated.
[0059]
In this embodiment, in addition to the same function as the first embodiment that automatically controls the number of multiplexed information signals to be transmitted in accordance with the set importance, the user directly controls the number of multiplexed signals manually. This is a wireless communication device having the function of
[0060]
As in the first embodiment, information signals such as video signals, audio signals, and control signals are transmitted from the spread spectrum transmission / reception unit 109 of the wireless communication apparatus A via the antenna 110.
[0061]
Here, as in the first embodiment, the control signal transmitted from the above-described wireless communication device A is a signal for controlling communication between the wireless communication device A and the wireless communication device B, and the lens 101 which is an imaging unit. A signal indicating a state, a signal indicating data-specific information such as the content, type, and compression rate of transmitted data. In addition, since the control signal is desired to be transmitted reliably, unlike the image signal and the audio signal, the number of multiplexed signals is such that the data of high importance is transmitted with a smaller number of multiplexing than at least the image signal and the audio signal. It is controlled by the control unit 210.
[0062]
The transmitted information signal is received by the antenna 201 of the wireless communication apparatus B and input to the spread spectrum transmission / reception unit 202. Here, as described in the first embodiment, the received signal is demodulated, subjected to various processing in the image expansion circuit 203, the communication protocol unit 204, and the NTSC encoder 205, and is output to the monitor 206.
[0063]
Further, as in the first embodiment, the wireless communication device B not only receives an information signal such as a video signal or an audio signal from the wireless communication device A, but also controls the imaging unit of the wireless communication device A such as zoom / focus. The control signal to be transmitted is transmitted to the wireless communication apparatus A.
[0064]
These various information signals (information signals transmitted between the wireless communication device A and the wireless communication device B) have a multiplexing number based on the importance set in each wireless communication device, as in the first embodiment. It is controlled. Here, the degree of importance is a set value set in advance or arbitrarily set by the user using the setting circuits 113 and 211.
[0065]
Multiplex selection units 701 and 801 are external switches, and the user can control the number of multiplexed information signals by operating the multiple number selection units 701 and 801 based on their own judgment. That is, the multiplex number control units 702 and 802 process the multiplex number set based on the multiplex number selection units 701 and 801 with higher priority than the multiplex number automatically determined by the importance determination circuits 111 and 209. Control based on the judgment of the user can be performed. For example, when the content of the data to be transmitted is important and the user determines that the data is to be transmitted reliably, the multiplex number can be controlled to be reduced as much as possible. Further, if the user decides to transmit as much data as possible even if some errors occur, it is possible to control so that the number of multiplexing is as large as possible.
[0066]
As described above, in the second embodiment of the present invention, by providing an external switch such as the multiplex number selection units 701 and 801 so that better wireless transmission can be performed in various transmission environments, the user can It is possible to provide a wireless transmission device that can be controlled by itself and that is easier for the user to use.
[0067]
The present invention can be implemented in various forms without departing from the spirit or main features thereof. For example, in the present embodiment, the case of performing wireless communication between two wireless communication devices has been described, but wireless communication having the same function can be performed between a plurality of wireless communication devices. Accordingly, the above-described embodiments are merely examples in all respects, and should not be interpreted in a limited manner.
[0068]
【The invention's effect】
According to the communication apparatus and communication method of the present invention, good data transmission is possible.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a wireless communication apparatus A according to a first embodiment.
FIG. 2 is a block diagram illustrating a configuration of a wireless communication apparatus B according to the first embodiment.
FIG. 3 is a block diagram illustrating in detail the configuration of the transmission units of the spread spectrum transmission / reception units 109 and 202 according to the first embodiment.
FIG. 4 is a block diagram illustrating in detail the configuration of the receiving units of the spread spectrum transmitting / receiving units 109 and 202 according to the first embodiment.
FIG. 5 is a block diagram illustrating a configuration of a transmission unit in a conventional spread spectrum communication apparatus.
FIG. 6 is a block diagram illustrating a configuration of a receiving unit in a conventional spread spectrum communication apparatus.
FIG. 7 is a block diagram illustrating a configuration of a wireless communication apparatus A according to a second embodiment.
FIG. 8 is a block diagram illustrating a configuration of a wireless communication apparatus B according to a second embodiment.

Claims (6)

Imaging means for generating an image signal using a lens and an imaging element;
Modulation means for modulating a control signal indicating the state of the imaging means or an image signal generated by the imaging means using one or more spreading codes;
And a transmitting means for transmitting the control signal or the images signals modulated by the modulation means,
The communication device according to claim 1, wherein the modulation means makes the number of spreading codes used for modulating the control signal smaller than the number of spreading codes used for modulating the image signal.   2. The communication apparatus according to claim 1, wherein the modulation unit makes the number of spreading codes used for modulating the control signal smaller than the number of spreading codes used for modulating the audio signal. Receiving means for controlling the operation of the imaging means, and receiving a control signal modulated with a smaller number of spreading codes than the number of spreading codes used for modulating the image signal;
Demodulating means for demodulating the control signal received by the receiving means,
The communication apparatus according to claim 1, wherein an operation of the imaging unit is controlled using a control signal demodulated by the demodulation unit. A communication method of a communication apparatus having an imaging means for generating an image signal using a lens and an imaging element,
A modulation step of modulating a control signal indicating the state of the imaging means or an image signal generated by the imaging means, using one or more spreading codes;
And a transmission step of transmitting the control signal or the images signals modulated by the modulation step,
The communication method according to claim 1, wherein the modulation step makes the number of spreading codes used for modulating the control signal smaller than the number of spreading codes used for modulating the image signal.   5. The communication method according to claim 4, wherein in the modulation step, the number of spreading codes used for modulating the control signal is made smaller than the number of spreading codes used for modulating the audio signal. A receiving step for controlling the operation of the imaging means, and receiving a control signal modulated with a smaller number of spreading codes than the number of spreading codes used for modulating the image signal;
A demodulation step of demodulating the control signal received in the reception step;
The communication method according to claim 4, further comprising a control step of controlling an operation of the imaging unit using the control signal demodulated in the demodulation step.

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