JP2006074609A - Super-wideband radio transmitter, super-wideband radio receiver and super-wideband radio transmission/reception system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device to perform radio transmission/reception in a super-wideband by a simple device. <P>SOLUTION: Transmission data are converted into desired pieces of bit data by a control signal generation part 100 and supplied to a chirp signal generation part 110. The chirp (CHIRP) signal generation part 110 has a data discrimination circuit 111, a lamp signal generation circuit 112 and a frequency control oscillator 113 whose frequency is variable, etc., each piece of bit data is converted into an up chirp signal which changes from a first frequency to a second frequency and a down chirp signal which changes from the first frequency to the second frequency and the chirp signals are transmitted to an antenna via a high frequency amplifier 120. On the receiving side, the chirp signals are separated by a plurality of predetermined band pass filters, detection signals are outputted by every filter and each detection signal is compressed, combined by a plurality of delay circuits having a predetermined delay amount and bit data at the time of transmission are demodulated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultra-wideband radio transmission / reception system that has been attracting attention in the field of digital radio communication systems, and particularly suitable for transmitting or receiving high-density digital information using a very wide frequency band. The present invention relates to a broadband wireless transmission device and an ultra-wideband wireless reception device.

In recent years, the frequency resources of radio waves that can be used by many mobile radios have decreased, and it is extremely difficult to allocate frequencies that are not used by existing radio frequency systems when introducing new radio communication systems. It has become.
Thus, in such a technical field, an ultra-wideband wireless transmission system is attracting attention as a wireless technology for effectively reusing frequency resources.
This ultra-wideband wireless transmission system (Ultra Wideband transmission system, usually called UWB) is a source that converts a data signal into an extremely fine pulse signal and supplies it as a baseband signal to a transmission medium. When the pulse width of the data to be transmitted is set to several nS, the occupied bandwidth occupied by a series of transmission information is several GHz, which is a wide occupied frequency band having almost the carrier frequency.

In such UWB wireless communication, it has become an extremely wide band transmission method compared to the bandwidth used in the existing wireless LAN, the wireless transmission and reception method of this method, the frequency spectrum of the existing wireless transmitter, This overlaps the frequency range used by the wireless receiver.
However, in the case of the UWB wireless transmission / reception system, the transmission power is distributed over a wide frequency band, so the level of the widely distributed frequency spectrum is extremely small at each frequency, and communication is performed in a specific frequency band. It can also be handled as a noise level signal that has little effect on existing wireless communications.
Therefore, much research has been done to be utilized as a new frequency resource in the field of wireless communication.
JP2003-204311 Nikkei Electronics 2003.2.17. (98-121P)

  As described above, in order to realize the UWB communication method, a circuit for processing a signal wave in a very high frequency region is necessary. For example, even if the power handles a small current consumption, an actual circuit Will be realized with high density integrated circuits (LSIs), and advanced technology and high difficulty are required.

For example, in the monopulse UWB wireless communication system, a monopulse signal as shown in FIG. 14A having a pulse width of 1 to several tens of nS modulated by information is transmitted as a radio wave as it is.
For such a monopulse signal waveform, it is conceivable to use a high-density integrated circuit that prepares a ROM table in which data to be a monopulse waveform is stored in advance and reads this ROM table with an ultra-high-speed clock. Yes.
There is also a need for a signal processing semiconductor integrated circuit that can be modulated with transmission data by controlling the read timing.
Furthermore, a modulation method that directly and intermittently transmits high-frequency radio waves transmitted to a transmission medium using high-speed digital data is also being studied. It is extremely difficult to manage to stay within.

  In addition, a circuit system that realizes the conventional DS (direct diffusion) technology in a higher frequency region has been studied. However, in reality, the transmission path parameters including all transmission / reception systems, etc. When considered, there is a problem of high difficulty.

  Furthermore, when a transmission signal wave transmitted as a radio wave with a direct impulse (monopulse) signal is greatly affected by multipath and other influences on the transmission path, there is a problem that the original pulse waveform cannot be left on the receiving side. This is because there is a problem in that uniform group delay characteristics cannot be secured over a wide frequency as a whole transmission / reception system including the transmission path, and the band is limited. There are a plurality of characteristics such as circuit filter characteristics, transmission path multipath, and fading, which are also related to problems to be solved.

  Therefore, if the above-mentioned problems are not solved, even if the signal received on the receiving side is simply analog-digital converted (binarized), the original desired signal shape is optimally set on the receiving side, that is, transmitted. It is difficult to demodulate as a signal similar to the time signal waveform.

According to the regulations of the Radio Law of each country, the following problems occur in the case of UWB wireless transmission / reception systems.
FIG. 14B shows an example of a spectrum template in which the allowable level of electromagnetic wave radiation intensity defined by the US FCC is on the vertical axis and the frequency is on the horizontal axis. In the UWB wireless communication system, the signal energy is inevitably increased. Since it has an ultra-wideband spectrum, it may be difficult to be within the spectrum template that defines the emission limit level of the Radio Law specified in each country.

The ultra-wideband wireless transmission / reception system of the present invention was made to alleviate such problems,
High-density transmission data (pulse signal) is constructed with a chirp waveform that starts from a predetermined first frequency and ends at a predetermined second frequency, and the signal of this chirp waveform is intermittently transmitted by a transmission means. Are transmitted to the wireless section, and the chirp waveform signal is received by the receiving means arranged at a separated position, and the transmission data is demodulated.

  The radio transmission apparatus of the present invention includes a control signal generation unit that modulates transmission data, and a first frequency to a second frequency, or a second frequency to a first frequency based on an output of the control signal generation unit. Frequency generation means for generating a chirp signal waveform that changes in frequency and transmission means for transmitting the output of the frequency generation means are provided.

In the embodiment of the present invention, when the presence of a wireless device that causes interference is confirmed in the UWB wireless transmission / reception area, the frequency that causes interference is changed by changing the sweep characteristic that forms the chirp signal waveform. Signal transmission can be easily prohibited.
Even if this measure for preventing interference is applied, it is possible to prevent the occurrence of transmission data error data.

  The wireless receiver of the present invention includes a receiving unit that receives a radio wave having a chirp signal waveform, a plurality of band-pass filters that detect a chirp signal received by the receiving unit for each predetermined band, and each of the filters. Detecting means for detecting the output envelope, delay means for sequentially delaying and compressing the detection output of the detecting means for a predetermined time, and combining the compressed outputs of the delay means to output a received composite signal It is provided with a synthesis means.

When there is an interference wave in the UWB wireless reception environment, the wireless reception device of the present invention controls so that a part of the signal detected for each predetermined region of the received chirp signal waveform is not output by the switching means, The interference wave signal component can be easily removed, and the demodulated signal is configured by compression / combination, so that the BER (signal error rate) is hardly lowered even by removing the interference wave.
As another embodiment of the present invention, in order to further increase the data transfer rate in the ultra-wideband wireless transmission / reception, the transmission side converts low-speed transmission data into a high-speed pulse rate for ultra-wideband. For example, a code spreading means, and a despreading means for converting the received signal converted into the high-speed pulse rate on the receiving side into low-speed received data can be provided.

  In the present invention, transmission data that is information to be transmitted is constructed with a chirp waveform that continuously changes for a predetermined period in accordance with the bit transmission rate, and therefore a transmission system using a UWB wireless transmission / reception system is employed. In this case, the transmission signal can be realized with a simple circuit configuration, and the power spectrum at the time of transmission can be easily managed in a desired range. Moreover, since it is sufficient to perform signal processing divided for each band at the time of reception, various problems based on a wide group delay characteristic of the transmission path can be reduced.

That is, the S / N ratio can be improved by the delay / compression processing of the signal data, and the BER (Bit error rate) can also be reduced.
In addition, despite the UWB communication method, it is easy to fit the transmission energy within a specified spectrum template.

In the ultra-wideband radio transmission / reception system of the present invention, the voltage variable oscillator and the like are controlled based on transmission data (pulse signal) or high-speed transmission data directly spread by, for example, a PN code sequence, and based on each series of bit data. A chirp (CHIRP) signal is generated that changes with a predetermined characteristic from the first frequency to the second frequency or from the second frequency to the first frequency.
A chirp signal swept in a predetermined range is intermittently transmitted from the radiating means to the radio section based on a predetermined bit transfer rate, and is received by the receiving means arranged at a separated position.
The receiving means compresses the envelope output signal of the filter means by a plurality of filter means for extracting a predetermined frequency of the chirp signal by a delay means for delaying by a predetermined time, converts it to a monopulse waveform, and converts the rate if necessary. The transmission information is decoded by despreading or the like.

FIG. 1 shows an example of a transmission side block diagram for realizing the ultra wideband wireless transmission / reception system of the present invention.
In this figure, reference numeral 100 denotes a control signal generator, and this control signal generator 100 can perform various kinds of signal processing on transmission data obtained by converting transmission information into a digital signal.
In the case of FIG. 1, the transmission data input to the control signal generator 100 is supplied to the arithmetic unit 103, and the spread signal generator (PN) driven by the clock supplied from the synthesizer 101 that generates a predetermined clock frequency. Is converted into a high-speed spreading code by the output of the sequence code generator) 102. For example, a low-speed bit data such as a simple measurement pulse waveform, a sensing signal, various control signals in a factory, or a pulse modulation signal is output. But you can.

A chirp signal generation unit 110 includes a data determination circuit 111, a ramp signal generation circuit 112, and a frequency controlled oscillator 113 whose frequency varies according to an output signal of the ramp signal generation circuit 112.
According to this embodiment, the bit data output from the control signal generation unit 100 is determined as binary data by the data determination circuit 111, and a value “1” or “0” is supplied to the ramp signal generation circuit 112. The The output frequency of the frequency controlled oscillator 113 is controlled based on the ramp signal generated based on the binary data.
Specific examples of the chirp signal waveform and the ramp signal waveform are shown in FIGS.
The chirp signal waveform (a) is a signal whose frequency changes (sweeps) according to the level of the ramp signal waveform (b). For example, in the case of FIG. 2, the period Ts during which the ramp signal is equal to or higher than a predetermined level Vth. So that the alternating signal is swept.
Also, the sweep period is determined by the intermittent signal (114) shown in FIG. 2 (c), and the logic circuit 140 is controlled by this signal as will be described later, so that the radio wave is output only during the sweep period. Can do.

Since the frequency of the alternating signal forming the chirp signal is changed in accordance with the level of the ramp signal waveform, in the sweep period Ts which is a reference of the bit rate, a straight line from the first frequency f1 to the second frequency f2 The next chirp signal is output after a predetermined period TR based on the bit data input next and the next input bit data.
In this embodiment, for example, the data “1” in the periods t1 and t2 is an up-chirp signal wave, and when the ramp signal reaches a predetermined level Vth, the frequency continuously changes from f1 to a higher frequency f2. It is controlled to change.
In addition, when the data becomes “0” as seen in the period t3, the ramp signal has a reverse slope and becomes a down chirp signal wave, which continuously decreases from the higher frequency f2 and decreases to the lower one. Control is performed to reach the frequency f1.
The period TR is determined in relation to the transmission bit rate and is determined by the frequency allowed by the spectrum template.

The chirp signal output from the frequency controlled oscillator (VCO) 113 is radiated from the antenna via the high frequency power amplifier 120.
130 is an interference control circuit. In an environment where ultra-wideband wireless transmission / reception is performed by supplying the output of the interference control circuit 130 to the high-frequency amplifier 120 through the gate circuit 140 and controlling the output, Control can be performed so as not to emit interference waves of a specific frequency given to other wireless devices.
That is, the gate circuit 140 is opened by the signal of the intermittent signal 114 or the signal output of the interference control circuit 130 in the period TR in which the chirp signal is not output and the timing at which the frequency causing the interference described later is output. Control is performed so that the output of the high-frequency power amplifier 120 is turned off.

FIG. 3A shows the change of the sweep frequency in the chirp signal waveform on the frequency axis when the first frequency is f1 and the second frequency is f2, and FIG. Indicates the speed of the signal to sweep.
The time during which the frequency of each chirp signal is swept can be determined based on the rate matching of the control signal generator that determines the transfer rate of information or the actual transmission transfer rate. Generally, if the bit rate increases Also shorten the sweep time of each chirp signal.

For example, when the sweep frequency is changed from f1 to f2, when the bit rate is 50 Mbps, the sweep time is set to T1 = 20 nS or less as shown in A of FIG. 3B, and at 100 Mbps, T2 ( It is necessary to consider the period TR during which the sweep is interrupted.
In addition, the use range (f1 to f2) of the chirp frequency forming the chirp signal waveform is limited by the spectrum template defined by the Radio Law described above, and approximately 4 to 10 GHz when clearing the FCC spectrum mask. Can be adopted.
Further, this chirp signal waveform can be used as two kinds of chirp signals of 4 GHz to 7 GHz and 7 GHz to 10 GHz in consideration of the characteristics of the filter on the receiving side and the case of use as multiplex communication. Band division is also possible.

The chirp signal is controlled so that there is no output between the chirp signal, but the transfer bit rate becomes T = Ts + TR by appropriately selecting the period during which there is no output.
Further, the signal band fbw at the time of wireless communication using the chirp signal can be considered as a frequency | f1-f2 |, though it depends on the bit rate.

FIG. 4 shows a block diagram of a part which is a receiving unit of the ultra-wideband wireless transmission / reception system of the present invention.
In this figure, 201 is a wideband receiving antenna, 202 is a low noise high frequency amplifier for amplifying a wideband signal, and 203 is a distribution circuit for distributing the output of the low noise high frequency sound amplifier 203. In this block diagram, N outputs are output. Distributing.
Each distributed output is, for example, a band pass filter group consisting of N band pass filters BPF1, BPF2, BPF3... BPFn whose bandwidth fBW is set to be slightly larger than (fbw / N). (Hereinafter referred to as a bandpass filter BPF) 204, and the output of each bandpass filter BPF (1.2... N) is supplied to N detectors 205 that detect the envelope of the output signal.

  Reference numerals 206A and 206B denote first and second delay circuit groups each including N delay circuits having predetermined delay characteristics. In the case of the first delay circuit group 206A, (K-1) ts, In the case of the second delay circuit group 206B, the delay amount is set to (n−K) ts, where (K = 1, 2, 3,... N), as seen in the signal waveform shown below. The delay time difference amount is set to be a time ts (ts = Ts / N) obtained by dividing the sweep time Ts of the received chirp signal by N.

The outputs of the first and second delay circuit groups 206A and 206B are input to signal synthesizers 207A and 207B, respectively, and the outputs are supplied to the discrimination circuit 208.
The discriminating circuit 208 compares the output levels of the signal synthesizers 207A and 207B and outputs a significant signal (usually a signal having a higher signal level) as bit data “1” or “0”.
Then, the binarized bit data is supplied to the rate conversion circuit 209 and the decoding circuit 210, and the received transmission information is output.
The rate conversion circuit 119 returns the rate conversion processing operation of the transfer data performed at the time of transmission to the original signal processing rate. For example, when code spreading processing is performed at the time of transmission, the rate conversion circuit 119 is configured by a despreading circuit. This rate conversion circuit 119 is not necessarily required.

Hereinafter, demodulation of received data will be described in the case where the number N of band-pass filters in the receiving circuit is 5.
FIG. 5A shows a signal waveform when the received up-chirp signal waveform is output through, for example, five BPF filters.
In this case, the center frequency of the five BPFs (1.2.3.4.5) is set to be a frequency output when the sweep range of the chirp signal waveform is divided into five, so that each band As shown in the figure, the output of the pass filter BPF (1, 2, 3, 4, 5) is obtained as a signal having five frequencies that are different at time intervals t1, t2, t3, t4, and t5.

The envelope of each signal is obtained by the detector 205 as shown in FIG.
Further, the envelope signal wave Det (1, 2, 3, 4, 5) is sequentially delayed and outputted in each of the delay circuits constituting the next delay circuit group 206A, but the delay amount of the five delay circuits. As shown in FIG. 5C, the delay circuit group 206A is set so as to become sequentially smaller so as to become an integral multiple (d1, d2,... D5) of the time ts as shown by the arrows in the figure. Are collected on the tn time axis.
Then, the output signals gathered on the time axis are compressed and synthesized by the synthesizer 207A and converted into a monopulse waveform as shown in FIG.

For example, the chirp signal waveform is an up-chirp signal indicating bit data “1”. However, when the chirp signal waveform is a down-chirp signal waveform indicating bit data “0”, for example, the first delay circuit group 206A No detection envelope signal is collected on the time axis tn at the output point.
Therefore, when detecting the down-chirp signal waveform, the envelope detection output of each passband filter group 204 is detected by the second delay circuit group 206B.
Hereinafter, a case where a monopulse signal is detected from a down chirp signal waveform by dividing the chirp signal when the bit data is “0” into five will be described with reference to FIG.
In this case, as shown in FIG. 6 (a), the received down chirp signal is the time t (1, 2, 3) that passes through the filter sequentially from the bandpass filter BPF (1, 2.3.4.5). , 4, 5).

As shown in FIG. 6B, this signal is converted into an output waveform Det (1, 2, 3, 4, 5) from which each envelope is extracted in the next detector, and the delay time is the first delay circuit group 206A. 6 is supplied to the delay circuit DL (1, 2, 3, 4, 5) arranged so as to be opposite to the delay amount of each of the delay circuits, so that a signal synthesizer as shown in FIG. In 207B, each envelope signal is compressed and synthesized at a certain time axis tn.
In this case, the detection signal of the up-chirp signal waveform input to the second delay circuit group 206B is delayed in the direction of divergence in the delay circuit group 206B and is not collected on the specific time axis.

  The up-chirp signal received in this way forms a monopulse compressed and synthesized in the signal synthesizer 207A, and the received down-chirp signal forms a monopulse signal compressed and synthesized on the synthesizer 207B side. If the discriminating circuit 208 for comparing the signal components of the units 207A and 207B with each other and discriminating the output to correspond to “1” or “0” of the binary signal is provided, modulation is performed on the transmission side based on the bit data The detected signal can be detected.

In this case, the discrimination circuit 208 can be configured by a simple comparator. However, if a signal of a level higher than the signal synthesizer 207 (A / B) cannot be detected, it is discriminated that there is no received data. It is preferable to do.
Reference numeral 209 denotes a rate conversion circuit including a despreading circuit that despreads data when transmission information is spread by a PN sequence, and 210 is a decoding circuit for restoring transmission information from received data.

FIG. 7 is a block diagram showing a receiving means according to another embodiment of the present invention.
Also in this block diagram, similarly to the receiving means of FIG. 4, a broadband antenna 301, a low-noise, broadband high-frequency amplifier 302, and a distribution circuit 303 for supplying the output to N output terminals are provided.
The output of the distribution circuit 303 is supplied to a frequency conversion circuit 304 that performs N frequency conversions. The frequency conversion circuit 304 converts the chirp signal output from the distribution circuit 303 into a signal including a certain intermediate frequency IF, and the frequency signal received at a timing obtained by dividing the sweep range of the chirp signal by n. A frequency mixer 305 (1, 2, 3,... N) and a local oscillator 306 (1, 2, 3,... N) are provided so as to convert the intermediate frequency IF.

Then, the signal is supplied to a band pass filter circuit group 307 including N band pass filter circuits set so that a signal corresponding to the intermediate frequency IF of the signal output from the synthesizer circuit 304 passes.
Each output signal of the bandpass filter circuit group 307 is input to the detector 308, and the envelope waveform of the signal is detected.
The plurality of envelope detection signals output from each detector 308 indicate the signal level at the timing obtained by dividing the sweep range of the chirp signal waveform into N as shown in FIGS. .
Therefore, this envelope detection waveform is collected on a certain time axis immediately after receiving the chirp signal as described above by inputting to the delay circuit group 309 constituted by the next two sets of N delay circuits. In addition, a monopulse signal compressed and combined at this point can be formed in the signal combining circuits 310 and 311.

  Note that the delay amount of each delay circuit constituting the delay circuit group 309 is set to be substantially an integral multiple of the time ts obtained by dividing the sweep time Ts for forming the chirp signal waveform into n as described above. The delay amount is determined corresponding to the first and second delay circuits 206A and 206B shown in FIG.

That is, this embodiment also shows an arrangement of a first delay circuit group not hatched and another set of second delay circuit groups hatched. Then, a signal synthesizer 310 that synthesizes the output of the first delay circuit group that is not shaded, a signal synthesizer 311 that synthesizes the output of the second delay circuit group that is shaded, and the signal synthesizer 310. A control circuit 312 is provided for discriminating bit data from the output of 311 and performing various types of signal processing.
As described with reference to FIG. 4, the first delay circuit group and the signal synthesizer 310 obtain a combined output of the up chart signal in which the bit data is “1”. Further, as described with reference to FIG. 4, the delay amount of the second delay circuit group is set to be opposite to the arrangement of the first delay circuit group not hatched, and the second delay circuit group When the signal synthesizer 311 for synthesizing the outputs is provided, it is possible to detect a down chirp signal in which the bit data of the chirp signal is “0”.
Thus, by comparing the outputs of the two signal synthesizers 310 and 311 in the control circuit 312 having the discriminating function as described above, for example, bit data “1” which is an up chart signal, For example, it is possible to detect a signal in which bit data is “0”, which is a down chart signal, and to perform various types of signal processing.

  In the case of the ultra-wideband wireless receiver of the present invention shown in FIG. 7, the bandpass filter BPF (if) having the same configuration in which the extraction of the frequency when generating the monopulse from the chirp signal uses the same intermediate frequency as the passband. In addition, by designing the oscillation frequency of each local oscillator 306 (1 to n) to be determined by a synthesizer method, there is an advantage that the semiconductor integrated circuit is easy and the circuit design is suitable for mass production. .

By the way, in the case of the UWB wireless system, there is a problem of interference or interference with other ordinary wireless devices due to the wide frequency band.
That is, the carrier frequency (2, 4 GHz band, 5, 2 GHz band, etc.) in the order of GHz used for, for example, wireless LAN communication networks and satellite communication networks that have been used in the past is within the UWB wireless communication system band. And this carrier frequency becomes an interference frequency on the transmission side and an interfered frequency on the reception side.

FIG. 8 shows an example of a UWB wireless device that prevents the frequency that causes interference with other wireless devices from being output. 510 is an antenna changeover switch, 520 is a sweeper receiver, and 530 is an interference control circuit. Reference numeral 540 denotes a UWB transmitter.
The UWB transmitter 540 is a wireless transmission device that outputs a chirp signal as shown in FIG. 1 of the present invention, and the chirp signal modulated by transmission data via the b-contact of the antenna switch 510 at the time of information transmission. Is output.

In this example, the switch 510 is switched to the a contact when transmitting the radio wave composed of the chirp signal, and the carrier sense within the transmission band is performed by the sweeper receiver.
The RF signal wave received by this carrier sense is detected, and the detected level is supplied to the interference control circuit 530. The interference control circuit 530 includes a spectrum analyzer, a RAM for recording detection data, a control signal generation circuit, and the like, and when the frequency determined by the interference control circuit 530 that interference interference occurs matches the sweep frequency of the chirp signal. Supplies an interference prevention signal to the UWB transmitter 540.

  Since the UWB transmitter 540 includes the chirp signal generator 110 as shown in FIG. 1 of the present invention, the first frequency f1 to the second frequency for forming the chirp signal as shown in FIG. A ramp signal waveform is formed so that no interference frequency occurs during f2.

FIG. 9A shows an example of a ramp signal waveform for preventing an interference. For example, when an interference frequency f3 (5 GHz) is detected, a missing ramp signal is formed before and after the frequency f3. Control is performed so that the voltage controlled oscillator is driven only by the thick line portion.
In the case of FIG. 5B, similarly, when the interference frequency is f3, the sweep time is set to be zero at the timing ti including the frequencies before and after this frequency f3. Drive to be removed from the chirp signal waveform.

Next, a case will be described in which interference prevention control is performed in order to prevent the UWB receiver from being affected by the interference frequency on the receiving side as much as possible.
FIG. 10 shows a part of the block of the receiving apparatus shown in FIG. 4 of the present invention. The received chirp signal waveform is detected by, for example, N frequency units in the band-pass filter group 203 and detected. An envelope signal is formed via the device 204, and each output signal is then subjected to delay compression in a predetermined delay circuit group 205 to form a monopulse.

In the case of this embodiment, a selection switch group 510, a carrier sense circuit 520, and a switch selection circuit 530 are provided so as to be common to each circuit that performs this signal processing.
When the carrier sense circuit 520 detects the frequency of the interfered wave, a signal indicating the frequency is input to the switch selection circuit 530, and the interfered wave frequency corresponds to the sweep frequency of the chirp signal. . A switch SW (k) on the line of the signal processing circuit of the band pass filter corresponding to the frequency, for example, BPF (k), is opened.
Note that the carrier sense circuit 520 does not connect to the antenna input, but takes in the outputs of the N detectors 204 as shown by dotted lines in FIG. The selection circuit 530 may be controlled.
With this configuration, in the UWB wireless reception system of the present invention, the frequency component corresponding to the interfered frequency is removed from the chirp signal frequency band, and the BER can be improved.
In the above-described countermeasure against the interfered wave and the countermeasure against interference, it has been described that the presence of an interfering frequency in the frequency spectrum of the chirp signal of the present invention is detected by a sweeper receiver or a carrier sense circuit. In a communication environment in which the frequency to be obtained is known in advance, the chirp signal generation unit may be designed to perform sweep control so that such a frequency is not output on the transmission side.
Also, when the frequency component that causes interference is known in advance on the receiving side, it is also possible to set the filter characteristics and control the delay circuit characteristics so that the signal of the frequency component is not detected. .

  In the case of the above UWB communication system, it is constructed based on ultra-wideband transmission information, and it is unlikely that multi-station multiplex communication will be performed, but multiple ultra-wideband wireless transmission / reception systems exist in the same area In such a case, there is a possibility that a problem may occur in multi-station multiplex communication composed of broadband spectrum energy. However, in the ultra-wideband wireless transmission / reception system according to the chirp system of the present invention, the frequency spectrum of the transmitted radio wave is relatively easy to control, so that multi-station communication can be facilitated by multiplexing techniques as shown below. Become.

FIG. 11 shows the band setting when constructing an ultra-wideband wireless transmission / reception system using the chirp system of the present invention. The signal band occupied by the chirp signal is, for example, 1 GHz as shown in FIG. In the case of A, only by sweep control of the chirp signal, this can be multiplexed as 500 MHz bands B and C as shown in FIG.
Such frequency division multiplexing can be easily realized by appropriately setting the sweep frequency range of the chirp signal waveform as described above.

FIG. 12 also shows another embodiment for multiplexing channels of the ultra-wideband wireless transmission / reception system. In this embodiment, the sweep time profile of the frequency to be chirped is changed so as to become a specific function for each communication device. For example, in channel 1 (CH1), the sweep characteristic is set to change relatively slowly. Channel 2 (CH2) is set so that the sweep time is shortened.
For each channel, the passband of the bandpass filter and the delay amount of the delay circuit group are set corresponding to this profile, and transmission data of a different profile is detected (compression / accumulation) on the receiving side due to the difference in the delay amount. I can't do it.

In addition, the communication environment between the channels can be set so that a chirp signal waveform is generated in a time division manner as employed in the conventional communication method.
That is, as shown in FIG. 13, in the receiving unit composed of the bandpass filter BPF group 203, the detector group 204, and the delay circuit group 205 shown in the previous receiving circuit, the signal synthesizer that synthesizes the respective detection waveforms A switch group 401 that opens and closes at a predetermined timing is provided, and detection signals received by the switch group 401 are controlled in a time-sharing manner for each channel.

In the case of asynchronous, switching control is difficult before communication is started (until timing is captured). However, once communication is started and timing is captured by, for example, the bit synchronization circuit 402 between transmission and reception, based on the signal. Therefore, the SW control circuit 403 is controlled on the basis of the timing signal, and the switch group 401 is opened and closed at the timing of the own station by the output of the SW control circuit 403. By demodulating, unnecessary interference waves can be eliminated by this, and only the information of the target communication signal can be appropriately extracted.
Note that more advanced multi-station multiplex communication can be realized by applying a technology for performing data communication by shifting the time by a technology called time hopping (performed by spread spectrum communication).

As described above, the ultra-wideband wireless transmission / reception system of the present invention does not need to produce a thin monopulse signal having a pulse width of several tens of pS to several tens of nS, as seen in the conventional UWB wireless transmission / reception system. Since the changed carrier signal only needs to be output continuously, the line spectrum fluctuates in frequency when viewed in the frequency domain.
On the other hand, in the case of the UWB wireless transmission / reception method in which the transmission data is a monopulse method, the energy of the line spectrum is determined by the pulse shape, and when the transmission wave is viewed in the frequency domain, the pulse is Fourier transformed. This is a very marginal state.
In order to fit the result of the Fourier transform into a spectrum template defined by the Radio Law, a very complicated and accurate pulse shape technique is required, but the chirp signal waveform as in the present invention is required. In the case of an ultra-wideband wireless communication system that uses information transmission signals, the line spectrum has only a frequency fluctuation, so it is very easy to keep the radio wave intensity emitted during communication within the specified spectrum. In addition, it is possible to easily construct a radio facility for transmitting information to a frequency band that has already been used.

  Furthermore, since the power measurement method of the UWB wireless transmission / reception method is also measured with a narrow band filter, the power that actually falls in that band does not increase so much. That is, a sufficient radio channel link margin can be obtained by securing transmission power by frequency sweep and obtaining a demodulated signal by an operation of integrating the chirp received signal on the receiving side.

In the present invention, an up-chirp signal and a down-chirp signal are used as a technique for modulating information into a binary signal. However, the sweep range of the first frequency and the second frequency for generating the chirp signal is expressed as data. Bit data may be transmitted / received by setting to the low frequency side when “1” and setting to the high frequency side when the data is “0”.
Further, the sweep speed, which is the sweep profile, is changed in correspondence with “1” and “0” of the bit data, and on the receiving side, the passband characteristics of the bandpass filter and the delay amount of each delay circuit in the delay circuit group are changed. It is also possible to perform modulation / demodulation of transmission data by appropriately setting.

It is a block of the transmitting side apparatus of the ultra wideband wireless transmission / reception system of the present invention. It is a chirp signal waveform and explanatory drawing. It is explanatory drawing which shows the bandwidth of a chirp signal waveform. It is a block diagram of the receiving side apparatus of the ultra wideband wireless transmission / reception system of this invention. It is a signal waveform diagram for obtaining bit data from an up-chirp signal. It is a signal waveform diagram for obtaining bit data from a down chirp signal. It is a block diagram on the receiving side showing another embodiment of the present invention. It is a block diagram of the UWB wireless transmission apparatus which removed the interference wave. It is explanatory drawing of the sweep waveform signal for eliminating an interference frequency. It is a block diagram of a UWB wireless receiver for eliminating the influence of an interfered wave. It is explanatory drawing of the ultra wideband in the case of making this invention a multiplex radio | wireless communication system. It is explanatory drawing of the chirp signal which can be utilized when multiplexing between multiple stations. It is a block diagram which shows one Example of the receiving means which performs multiplex communication. It is explanatory drawing of the template which restrict | limits a monopulse signal waveform and a radiation area | region.

Explanation of symbols

100 control signal generator, 110 chirp signal generator,
120 high frequency amplifier, 203 distribution circuit, 204 filter circuit group, 206 delay circuit group

Claims (10)

  Based on the bit data, a chirp signal waveform that starts from the first frequency and sweeps to end at the second frequency is generated, and the chirp signal waveform is intermittently corresponding to the bit data position forming the digital transmission data. An ultra-wideband wireless transmission / reception system characterized in that a signal having a chirp waveform is received by a receiving means arranged at a remote position, and the digital transmission data is demodulated.   The chirp signal waveform sweeps up from the first frequency in the direction of increasing with time based on the sign of the transmission data, and down chirp swept in the direction of decreasing from the second frequency in time. 2. The ultra-wideband wireless transmission / reception system according to claim 1, wherein the transmission / reception system is formed by a signal waveform.   Control signal generating means for modulating transmission data, and a chirp waveform signal that changes continuously from the first frequency to the second frequency and from the second frequency to the first frequency based on the output of the control signal generating means An ultra-wideband radio transmission apparatus comprising: frequency generation means for generating a signal; and transmission means for transmitting the output of the frequency generation means.   Receiving means for receiving radio waves having a chirp signal waveform, N band-pass filters for dividing the bandwidth of the chirp signal received by the receiving means into N outputs, and outputs of the band-pass filters N detection means for detecting envelopes, delay means for sequentially outputting the detection outputs of the respective detection means by delaying by a predetermined time, and synthesis for combining the outputs of the delay means and outputting a reception composite signal Means and a demodulating means for decoding the output of the synthesizing means.   The chirp signal waveform output from the frequency generating means sweeps from a lower frequency to a higher frequency based on the first bit data to be transmitted, and from a higher frequency based on the second bit data to be transmitted. 4. The ultra wideband wireless transmission apparatus according to claim 3, wherein the apparatus is configured to be swept in a lower direction.   4. The ultra-wideband radio transmission apparatus according to claim 3, wherein the chirp signal waveform output from the frequency generation means is controlled so as not to exist within a range where a specific interference frequency is substantially swept. .   The delay means includes N first delay circuit groups in which a delay amount is set based on a time point when the sweep range of the chirp signal waveform is divided into N, the N first delay circuit groups, and the delay amount. The ultra-wideband radio receiving apparatus according to claim 4, comprising: a second delay circuit group arranged in a reverse direction.   5. The ultra-wideband radio receiving apparatus according to claim 4, wherein a switch group for selecting the outputs of the N delay means is provided, and an output of an interfered frequency is not selected by the switch group.   2. The ultra-wideband wireless transmission / reception system according to claim 1, wherein multiple communication between multiple stations is made possible by limiting a frequency sweep range of a chirp signal waveform transmitted to a transmission medium. In ultra-wideband wireless transmission / reception, code spreading means for converting low-speed transmission data to a high-speed pulse rate for ultra-wideband on the transmission side and low-speed reception of the reception signal converted to the high-speed pulse rate on the reception side An ultra-wideband wireless transmission / reception system comprising despreading means for converting data.

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