JP2008141747A - Receiver for ultra wideband communications, method of generating reproduction data for ultra wideband communications, and ultra wideband communications system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultra wideband communications technology, namely, a receiver for ultra wideband communications, method of generating reproduction data for ultra wideband communications, and ultra wideband communications system, wherein a modulation and demodulation technique of constantly transmitting a plurality of carriers in a wide frequency bandwidth is employed for a baseband communication using an ultra wideband and an automatic gain control amplifier having a wide dynamic range is set after a despread demodulation operation is performed, so as to reduce negative influence to other radio waves. <P>SOLUTION: They are provided with: a low-gain amplifier for reception which performs low-gain amplification on a received despread demodulation signal; a despread demodulator for demodulating the signal on which the low-gain amplification has been performed; a high-pass filter which blocks only an information signal band before spreading at an input terminal of the despread demodulator; a low-pass filter which passes only an information signal band before spreading at an output terminal of the despread demodulator; an automatic gain control amplifier which has a wide dynamic range and amplifies a signal demodulated by the despread demodulator to a signal having a constant amplitude level; and a determiner for determining the amplified signal to reproduce data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a receiver for ultra-wideband communication applied to an ultra-wideband communication system, a reproduction data generation method for ultra-wideband communication, and an ultra-wideband communication system.

  In general, traditional communication techniques have been designed to effectively use limited frequency resources by limiting the frequency bandwidth used as much as possible (that is, by narrowing the bandwidth). However, as the frequency bandwidth is narrowed, noise resistance (durability against communication channel noise), interference resistance (resistance to signal distortion due to signals of other channels, etc.) and the like deteriorate. As a result, there arises an inconvenience that an extra bandwidth of the communication path is consumed due to data retransmission or the like.

  In order to eliminate this inconvenience, an ultra wide band communication method using an ultra wide band baseband signal is known. In this communication system, communication is performed via a wireless communication path or a transmission path having a large attenuation such as an ADSL (Asymmetric Digital Subscriber Line).

  In the ultra-wideband communication system, data is transmitted and received by spreading data in a frequency band of about 1 GHz, for example. In a system using an ultra-wideband communication system, the spectrum is distributed over a very wide band (usually having a bandwidth of several hundreds KHz to several MHz), but the spectrum density is much smaller and other communications in the same frequency band. Even if it is done, it is almost unaffected. Even if the frequency bands collide, error correction is performed with a powerful error correction code added to the data.

  In the ultra-wideband communication method, since a weak spectrum is distributed over a wide frequency band, (1) many communications can be performed simultaneously on the same band, and (2) there is little influence on other stations (almost no ), (3) It is hardly affected by noise and other nodes, and (4) It is difficult to track and detect the signal contents, so that it has high secrecy.

  One of the typical ultra-wideband communication methods is the direct diffusion method. The direct spreading method is a method of multiplying the frequency band of the data string itself by multiplying the signal data with a pseudo-random number sequence having a bandwidth, modulating it, and transmitting it.

  That is, in this method, a digital signal having a narrow bandwidth and a high power density is modulated into a signal having a low power density and a wide bandwidth by adding a spreading code having a high bit rate to the digital signal. The receiver can extract only the signal having the same bit string as the pseudo-noise code from the received radio wave by the correlator and restore it to information data.

Among ultra-wideband communication systems, there is a communication system that uses impulses that are easy to realize a circuit (see Patent Document 1). The impulse is an instantaneous signal and the frequency spectrum is extremely wide, so that the influence on other bands can be reduced.
Japanese National Patent Publication No. 11-504480

  However, in Patent Document 1, since a high-power signal is output at the moment when an impulse is generated, other signals are affected.

  The present invention has been made in view of such circumstances, adopting a modulation / demodulation method in which a large number of carriers are continuously transmitted in ultra-wideband baseband communication, and having a high dynamic range after despreading demodulation processing. An ultra-wideband communication technology capable of reducing the influence on other radio waves by providing an automatic gain control amplifier, that is, a receiver for ultra-wideband communication, a reproduction data generation method for ultra-wideband communication, and an ultra-wideband communication system It is intended to provide.

  The present invention relates to a low gain amplifier that amplifies the received spread modulation signal by low gain, a despread demodulator that demodulates a signal that has been low gain amplified by the low gain amplifier, and between the low gain amplifier and the despread demodulator. A high-pass filter that blocks only the information signal band before spreading, a low-pass filter that is provided at the output terminal of the despread demodulator and passes only the information signal band before spreading, and the inverse filter A wide dynamic range automatic gain control amplifier that amplifies the signal demodulated by the spread demodulator to a signal having a constant level, and a determination unit that determines the signal amplified by the automatic gain control amplifier and reproduces the data. It is a receiver for ultra-wideband communication.

  Further, the received spread modulation signal is amplified by low gain, and the low gain amplified signal is subjected to high-pass filter processing that blocks only the information signal band before spreading, and the signal after this late-pass filter processing is demodulated, The demodulated signal is subjected to a low-pass filter process that passes only the information signal band before spreading, and the signal after the low-pass filter process is amplified to a signal having a certain level of amplitude. The reproduction data generation method for ultra-wideband communication is characterized in that data reproduction is performed from above.

  Also, a spread modulator that spreads and modulates transmission data into a wideband signal of a format in which a large number of carriers are transmitted continuously in time, and a transmission amplifier that amplifies the spread modulation signal spread and modulated by the spread modulator A transmitter for ultra wideband communication characterized in that the signal amplified by the transmission amplifier is transmitted as a baseband signal by wire or wireless, and a low gain amplifier for low gain amplification of the received spread modulation signal, A despreading demodulator that demodulates a signal gain-amplified by the low-gain amplifier, and a high-pass filter that is provided between the low-gain amplifier and the despreading demodulator and blocks only the information signal band before spreading And a low-pass filter provided at the output terminal of the despread demodulator for passing only the information signal band before spreading, and a signal demodulated by the despread demodulator at a constant level. A wide dynamic range automatic gain control amplifier that amplifies the signal to a signal having a signal amplitude and a determination unit that performs data reproduction by determining the signal amplified by the automatic gain control amplifier. An ultra-wideband communication system comprising a communication receiver.

  Therefore, according to the present invention, on the receiving side, it is possible to remove the influence of noise mixed in by the low gain amplifier and to obtain the effect that the receiving sensitivity can be improved.

  In addition, in the case of impulse communication, a modulation / demodulation method in which a large number of carriers are transmitted in time is adopted for ultra-wideband baseband communication, and an automatic gain control amplifier with a high dynamic range is provided after despread demodulation processing. Compared to the above, there is an effect that the influence on other radio waves can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a basic system configuration diagram showing an embodiment of the first aspect.

In the communication system of FIG. 1, the transmitter 11 includes a spread modulator 111 to which transmission data is input, and a transmission amplifier 112.

  The receiver 12 includes a low gain amplifier 121, a despread demodulator 122, an automatic gain control amplifier (AGC amplifier) 123, a level detector 124, and a determination unit 125 that outputs reproduction data.

  The transmitter 11 and the receiver 12 are connected via a transmission path / propagation path P.

  On the transmitter 11 side, the spread modulator 111 spread-modulates transmission data into a wideband signal in a format in which a large number of carriers are transmitted continuously in time. The transmission amplifier 112 amplifies the spread-modulated signal and performs wired or wireless transmission with the baseband signal.

  On the receiver 12 side, the reception low gain amplifier 121 receives the spread modulation signal and amplifies the signal so as not to degrade the SN. Thereafter, the signal is demodulated by the despreading demodulator 122, and the demodulated signal is amplified to a signal having a constant amplitude by the automatic gain control amplifier 123 having a wide dynamic range. To do. The received signal is only amplified by the low gain amplifier 121 for reception to the extent that SN is not degraded. Further, the despreading demodulator 122 despreads the interference signal mixed in the transmission path, and then amplifies it by the wide dynamic range automatic gain control amplifier 123. Therefore, compared with a system in which an automatic gain control amplifier is placed before the despreading demodulator, the demodulated signal is not distorted by the interference signal, and reception sensitivity is improved.

  FIG. 2 shows a system with further improved sensitivity in the communication system of FIG. In FIG. 2, a high-pass filter (hereinafter referred to as “HPF”) 411 that blocks only the information signal band before spreading is provided in the upstream or downstream of the transmission amplifier 112 on the transmitter 11 side. In FIG. 2, an HPF 421 that blocks only the information signal band before spreading is provided at the input terminal of the despreading demodulator 122 on the receiver 12 side, and the information signal band before spreading is provided at the output terminal of the despreading demodulator 122. A low-pass filter (LPF) that passes only the filter is provided.

  In the communication system of FIG. 2, by providing the HPF 411 as described above, the region where the input / output signal spectrum of the despreading demodulator 122 overlaps is eliminated. For this reason, noise mixing due to signal leakage in the despreading demodulator 122 can be considerably reduced, and the receiving sensitivity can be further greatly improved.

  FIG. 3 is an operation explanatory diagram of the communication system of FIGS. 1 and 2. 3 (a-1), (a-2), (a-3), (a-4) and FIGS. 3 (b-1), (b-2), (b-3), (b- In 4), the horizontal axis represents frequency and the vertical axis represents power density.

  3A-1 shows a signal spectrum at the output end of the transmission amplifier 112 of the transmitter 11, FIG. 3A-2 shows a signal spectrum at the input end of the despreading demodulator 122, and FIG. 3) shows the reference spread signal spectrum in the despread demodulator 122, and (a-4) shows the signal spectrum at the output end of the despread demodulator 122.

  3B-1 shows the signal spectrum at the output end (output end of the HPF 411) of the transmission amplifier 112 of the communication system with improved sensitivity shown in FIG. 2, and FIG. 3B-2 shows the despread demodulator 122. 3 (b-3) shows the signal spectrum of the reference spread signal in the despread demodulator 122, and FIG. 3 (b-4) shows the output of the despread demodulator 122. The signal spectrum at the end is shown.

  3 (a-1) to 3 (a-4), that is, in the communication system of FIG. 1, the transmitter 11 spreads a narrowband data signal and transmits it as a transmission signal. Various interference waves and noise are mixed in addition to the waves. Therefore, as shown in FIG. 3A-4, the correlation output with the reference spread signal is such that the received signal level and the reference spread signal leak directly to the output end in addition to the original desired correlation output. If it is low, a sufficient SN ratio cannot be obtained, and the communication quality may be greatly deteriorated.

  3 (b-1) to 3 (b-4), that is, in the communication system of FIG. 2, since the output of the transmitter 11 passes through the HPF 411, the signal of the desired correlation signal band is removed from the transmission signal itself, and reception is performed. Also on the side, the signal in the desired correlation signal band and the interference signal and noise from the other are removed again by the HPF 421 before the despreading demodulator 122. For this reason, interference signals and noise do not affect the correlation output.

  Also, with respect to the reference spread signal to the correlator in the despread demodulator 122, since the component of the desired correlation signal band is removed through the HPF 421, this does not leak and affect the correlation output. As a result, the correlation output is clearly divided into a desired correlation output and a noise component that circulates in a higher frequency range, so that only the desired correlation signal can be extracted by the subsequent LPF 423. Thereafter, by amplifying only the desired signal with the automatic gain control amplifier 123, a signal with greatly reduced noise can be reproduced, so that reception sensitivity can be greatly improved and communication quality is also improved. Since the HPF 421 is provided on the reception side, the HPF 411 on the transmission side is not essential.

  FIG. 4 is a basic system configuration diagram showing an embodiment of the second aspect. In the second embodiment, diffusion modulation is performed by a direct diffusion method. In other words, by multiplying the signal data by a pseudo-random number sequence having a bandwidth to widen the frequency band of the data sequence itself, and modulating and transmitting it, a digital signal with a narrow bandwidth and high power density is obtained. It can be changed to one with low power density and wide bandwidth.

  In the communication system of FIG. 4, the transmitter 21 includes a pseudo noise code generator 211 to which transmission data is input, a multiplier 212, and a transmission amplifier 213, and the receiver 22 includes a low gain amplifier 221, The clock recovery circuit 222 includes a pseudo noise code generator 223, a correlator 224, an automatic gain control amplifier 225, a level detector 226, and a determiner 227.

  On the transmitter 21 side, a pseudo noise code generator (PNG) 211 inputs a predetermined clock to generate a pseudo noise code, and the pseudo noise code and transmission data are multiplied by a multiplier 212 to generate a spread demodulated signal. Generate. Then, the spread modulation signal is amplified by the transmission amplifier 213 and transmitted by wire or wireless as the baseband signal.

  On the receiver 22 side, the low gain amplifier 221 receives the spread modulation signal and amplifies the signal so as not to degrade the SN. Then, after the clock is recovered from the amplified signal by the clock recovery circuit 222, a pseudo noise code generator 223 is used to generate a pseudo noise code. Then, the amplified reception signal from the low gain amplifier 221 is demodulated by the correlator 224 using the pseudo noise code. The wide dynamic range automatic gain control amplifier 225 amplifies the demodulated signal into a signal having a constant amplitude with a wide dynamic range, and the decision unit 227 determines this to reproduce data.

  FIG. 5 shows a system with further improved sensitivity in the communication system of FIG. In FIG. 5, an HPF 511 that blocks only the information signal band before spreading is provided after the transmission amplifier 213 on the transmitter 21 side.

  Also, an HPF 521 that blocks only the information signal band before spreading is provided at the input terminal of the low gain amplified signal for reception of the correlator 224 on the receiver 22 side. An HPF 522 that blocks only the information signal band is also provided at the input terminal of the pseudo-noise code of the correlator 224. Furthermore, an LPF 523 that passes only the information signal band before spreading is provided at the output terminal of the correlator 224.

  In the communication system of FIG. 5, by providing a filter as described above, it is possible to considerably reduce noise mixing, and it is possible to further significantly improve reception sensitivity.

  FIG. 6 is a basic system configuration diagram showing an embodiment of the third aspect. Also in the third embodiment, diffusion modulation is performed by the direct diffusion method.

  In the communication system of FIG. 6, the transmitter 31 divides a predetermined clock, and a first pseudo-noise code generation that generates a first pseudo-noise code using the frequency-divided clock from the frequency-divider 311. Generator (PNG) 3121, a second pseudo-noise code generator (PNG) 3122 for generating a second pseudo-noise code by the predetermined clock, transmission data and first pseudo-noise code generator (PNG) 3121 The first multiplier 3131 that multiplies the first pseudo-noise code to be generated, the second pseudo-noise code generated by the second pseudo-noise code generator 3122, and the signal from the first multiplier 3131 are multiplied. It comprises a second multiplier 3132 and a transmission amplifier 314.

  The receiver 32 also includes a low gain amplifier 321, a clock recovery circuit 322, a frequency divider 323 that divides the clock from the clock recovery circuit 322, and a first pseudo that operates according to the clock from the clock recovery circuit 322. A noise code generator 3241, a second pseudo noise code generator 3242 that operates according to the divided clock from the frequency divider 323, an amplified received signal from the low gain amplifier 321, and a first pseudo noise code generator 3241. A first correlator 3251 that receives a pseudo-noise code from the first automatic gain control amplifier 3261 that receives a signal from the first correlator 3251 and a signal from the first automatic gain control amplifier 3261 A second correlator 3252 that inputs a signal from the second pseudo-noise code generator 3242 and a second self-input that receives a signal from the second correlator 3252. A gain control amplifier 3262 consists determiner 328 Metropolitan which inputs a signal from the second automatic gain control amplifier 3262 outputs the reproduced data.

  On the transmitter 31 side, a frequency divider 311 that inputs a predetermined clock sends a frequency-divided signal to a first pseudo noise code generator (PNG) 3121. The first pseudo-noise code generator (PNG) 3121 generates a first pseudo-noise code from the divided clock, and multiplies the pseudo-noise code and transmission data by a multiplier 3131 to generate a primary spread demodulated signal. To do. On the other hand, a second pseudo-noise code generator (PNG) 3122 receives the predetermined clock, generates a second pseudo-noise code from this clock, and a primary spread demodulated signal from the pseudo-noise code and the multiplier 3131. To generate a second spread modulation signal, which is amplified by the transmission amplifier 314 and transmitted by wire or wireless as the baseband signal.

  On the receiver 32 side, the low gain amplifier 321 amplifies the received spread modulation signal to such an extent that the spread modulation signal is received and the SN is not deteriorated. Then, after the clock is regenerated from the amplified signal by the clock regenerating circuit 322, a pseudo noise code is generated by the first pseudo noise code generator 3241 using this, and the first correlator is generated by using this pseudo noise code. The received signal amplified by the low gain amplifier 321 is first spread demodulated by 3251 and amplified by the first automatic gain control amplifier 3261. On the other hand, the frequency divider 323 generates a pseudo noise code by the second pseudo noise code generator 3242 using the predetermined clock, and an automatic gain control amplifier 3262 by the second correlator 3252 using the pseudo noise code. The received signal amplified in step (2) is second-order spread demodulated and amplified by a second automatic gain control amplifier 3262 to a signal having a constant level with a wide dynamic range. A signal from the second automatic gain control amplifier 3262 is input to the determiner 328, and the determiner 328 outputs reproduction data.

  FIG. 7 shows a system with further improved sensitivity in the communication system of FIG. In FIG. 7, an HPF 611 that blocks only the information signal band before spreading is provided after the transmission amplifier 314 on the transmitter 31 side.

  An HPF 621 that blocks only the information signal band before spreading is provided at the input terminal of the low gain amplified signal for reception of the first correlator 3251 on the receiver 32 side. In addition, an HPF 622 that blocks only the information signal band is also provided at the pseudo noise code input terminal of the first correlator 3251. Furthermore, the output terminal of the first correlator 3251 is provided with an LPF 625 that passes only the information signal band before spreading.

  An HPF 623 that blocks only the information signal band before spreading is provided at the input terminal of the low gain amplified signal for reception of the second correlator 3252. An HPF 624 that blocks only the information signal band is also provided at the pseudo noise code input terminal of the second correlator 3252. Furthermore, an LPF 626 that passes only the information signal band before spreading is provided at the output terminal of the second correlator 3252.

  As described above, in the present invention, a modulation / demodulation method in which a large number of carriers are transmitted continuously in time is adopted for ultra-wideband baseband communication, and an automatic gain control amplifier with a high dynamic range is provided after despreading demodulation processing. Therefore, the influence on other radio waves can be reduced as compared with the case of impulse communication.

  In addition, the received signal is amplified to the extent that SN is not degraded by the low gain amplifier at the first stage, and after despreading the interference signal mixed in the transmission line by the despreading demodulator, it is amplified by the automatic gain control amplifier with a high dynamic range. Therefore, compared with the case where an automatic gain control amplifier is placed in front of the despreading demodulator, the demodulated signal is not distorted by the interference signal, and the reception sensitivity is improved.

  In addition, by providing an HPF at the input of the despreading demodulator, it is possible to considerably reduce noise mixing due to signal leakage in the despreading demodulator and to greatly improve reception sensitivity.

  Further, it is possible to employ direct diffusion type diffusion modulation in which the PN signal from the pseudo noise generator is simply multiplied to the data signal for the diffusion modulation. In this case, it is possible to realize a broadband signal in which a large number of carriers are transmitted continuously in time with a simple circuit at a low cost, and the influence of interference on others compared to an impulse-based ultra-wideband communication system. Can be reduced.

  Further, the spread modulation and despread demodulation processes are processed in two stages, and the automatic gain control amplifier is also divided in two stages. That is, if the gain is too high at one stage and oscillation due to noise occurs, the gain can be divided by using two stages. As a result, a lower level signal can be demodulated stably and the sensitivity is improved. In this case, sensitivity can be improved by adding a filter before and after each of the two stages of correlation processing.

  It should be noted that sensitivity can be further improved by setting the spread modulation, despread demodulation processing, or automatic gain control to three or more stages.

FIG. 1 is a basic system configuration diagram showing an embodiment of the first aspect. It is a figure which shows the system which further improved the sensitivity in the communication system of FIG. FIG. 3 is an operation explanatory diagram of the communication system of FIG. 1 and FIG. 2, and (a-1) to (a-4) and (b-1) to (b-4) are diagrams illustrating the spectrum of each part. FIG. 2 is a system configuration diagram showing an embodiment in which the spread modulator and the despread demodulator in FIG. 1 are replaced with a direct spread type modulator and a demodulator, respectively. It is a figure which shows the system which further improved the sensitivity in the communication system of FIG. FIG. 5 is a system configuration diagram showing an embodiment in which the spread modulation and despread demodulation processes in FIG. 4 are changed to be processed in two stages. It is a figure which shows the system which further improved the sensitivity in the communication system of FIG.

Explanation of symbols

11, 21, 31 Transmitter 12, 22, 32 Receiver 111 Spread modulator 112, 213, 314 Transmit amplifier 121, 221, 321 Low gain amplifier 122 Despread demodulator 123, 225, 3261, 3262 Automatic gain control amplifier

Claims (3)

A low gain amplifier for amplifying the received spread modulation signal with low gain;
A despreading demodulator that demodulates a signal gain-amplified by the low-gain amplifier;
A high pass filter provided between the low gain amplifier and the despreading demodulator and blocking only the information signal band before spreading;
A low-pass filter that is provided at the output terminal of the despreading demodulator and passes only the information signal band before spreading;
A wide dynamic range automatic gain control amplifier that amplifies the signal demodulated by the despreading demodulator into a signal having a constant level of amplitude;
A determination unit for determining the signal amplified by the automatic gain control amplifier and performing data reproduction;
A receiver for ultra-wideband communication, comprising: Low gain amplification of received spread modulation signal,
For this low gain amplified signal, perform high-pass filter processing to block only the information signal band before spreading,
Demodulate the signal after this high-pass filter processing,
Perform a low-pass filter process that passes only the information signal band before spreading for this demodulated signal,
Amplify the signal after this low-pass filter processing to a signal with a certain level of amplitude,
Data reproduction is performed from this constant level amplitude signal.
A reproduction data generation method for ultra-wideband communication. A spread modulator that spreads and modulates transmission data into a wideband signal of a format in which a large number of carriers are transmitted continuously in time, and a transmission amplifier that amplifies the spread modulation signal spread and modulated by the spread modulator A transmitter for ultra wideband communication, wherein the signal amplified by the transmission amplifier is transmitted as a baseband signal by wire or wirelessly;
A low gain amplifier for low gain amplification of the received spread modulation signal, a despread demodulator for demodulating a signal low amplified by the low gain amplifier, and provided between the low gain amplifier and the despread demodulator, A high-pass filter that blocks only the information signal band before spreading, a low-pass filter that is provided at the output terminal of the despreading demodulator and passes only the information signal band before spreading, and the despreading demodulator A wide dynamic range automatic gain control amplifier that amplifies the demodulated signal to a signal having a constant level amplitude, and a determination unit that determines the signal amplified by the automatic gain control amplifier and reproduces the data. A receiver for ultra-wideband communication,
An ultra-wideband communication system comprising:

Images