KR100790123B1 - Wireless transmitter and receiver for use in an ultra-wideband direct spread pulse communication system - Google Patents

Abstract

According to the present invention, in the ultra-wideband direct spread pulse communication method in which two series of data are transmitted and received using different spread pulse sequences, the D / U (Desired / Unwanted) ratio of the correlation output is improved without increasing the number of data. To this end, the spreading codes used in the matching filter of the radio transmitter according to the present invention are the (2 * N-2) th and (2 * N) th values of the cross-correlation signal between the first spreading code and the second spreading code. Is greater than or equal to 0, the (2 * N-3) th value and the (2 * N + 1) th value of the autocorrelation signal of the first spreading code are less than or equal to 0, and the (2 *) of the autocorrelation signal of the second spreading code N-3) th value and (2 * N + 1) th value is 0 or less. As a result, it is not necessary to reduce the peak value of the cross-correlation signal and to increase the value other than the peak value, so that the D / U ratio becomes good.

Ultra-wideband direct spread pulse communication, wireless transmitter, wireless receiver, matched filter

Description

WIRELESS TRANSMITTER AND RECEIVER FOR USE IN AN ULTRA-WIDEBAND DIRECT SPREAD PULSE COMMUNICATION SYSTEM}

1A and 1B are explanatory diagrams showing a test system for evaluating autocorrelation characteristics and cross-correlation characteristics;

2 is an explanatory diagram showing autocorrelation characteristics and cross-correlation characteristics of a Braker code of 7 chips;

3 is an explanatory diagram showing calculation of mutual signals;

4A and 4B are explanatory diagrams showing a test system for evaluating autocorrelation characteristics and cross-correlation characteristics;

5 is an explanatory diagram showing a case where the code of FIG. 2 is evaluated by the evaluation system for the ultra-wideband direct spread pulse communication method;

6 is an explanatory diagram showing amplitude modulation of a transmission pulse signal sequence;

7 is an explanatory diagram showing autocorrelation characteristics and cross-correlation characteristics of a spreading code according to an embodiment of the present invention;

FIG. 8 is an explanatory diagram showing a case where the code of FIG. 7 is evaluated by an evaluation system for an ultra-wideband direct spread pulse communication method; FIG.

9 is an explanatory diagram showing a spreading code according to an embodiment of the present invention;

10 is an explanatory diagram showing a case where the code of FIG. 9 is evaluated by the evaluation system for the ultra-wideband direct spread pulse communication method;

FIG. 11 is an explanatory diagram showing a case where the code of FIG. 9 is evaluated by the evaluation system for the ultra-wideband direct spread pulse communication method; FIG.

12 is an explanatory diagram showing an ultra-wideband radio system;

13 is an explanatory diagram showing a matching filter on the transmitter side;

14 is an explanatory diagram showing a matching filter on the receiver side;

15 is an explanatory diagram showing autocorrelation characteristics;

16 is an explanatory diagram showing an ultra-wideband direct spread pulse communication method;

17 is an explanatory diagram showing cross-correlation characteristics;

18 is an explanatory diagram showing cross-correlation characteristics;

The present invention relates to a wireless transmitter and a wireless receiver, and more particularly, to a wireless transmitter and a wireless receiver using an ultra-wideband direct spread pulse communication method in which two sets of data are transmitted and received through different spread pulse sequences.

As a new data communication method of spread spectrum communication, an ultra-wideband wireless communication method that spreads data in a very wide frequency band of several GHz and superimposes data on a pulse without using a carrier wave to transmit and receive is attracting attention. The ultra wideband wireless communication system is, for example, "Characteristic Evaluation of Internally Turbo-Coded Ultra Wideband-Impulse Radio (ITU-UWB-IR)" (YAMAMOTO Yoshitake, Otsuki Tomoaki, Electronics Co., Ltd.) See Technical Report of IEICE, pp. 25-30, RCS 2002-55 (2002-05). In the ultra-wideband wireless communication method, since data transmitted to each frequency band has only a noise level, interference with wireless devices using the same frequency band does not cause interference, and power consumption is small. As a prior art to which this ultra-wideband radio system is applied, there is disclosed in Japanese Patent No. 3564468 (name: ultra-wideband radio transmitter and ultra-wideband radio receiver and ultra-wideband radio communication method) (hereinafter referred to as "Patent Document 1").

Hereinafter, the ultra-wideband radio system disclosed in Patent Document 1 will be described with reference to FIG. 12. FIG. 12 shows the configuration of the transmitter side shown in FIG. 1 of Patent Document 1 and the configuration of the receiver side shown in FIG. In FIG. 12, the delay time controller 2 of the transmitter generates a monocycle pulse based on the data signal to be transmitted, and outputs the output signals K1 to K3 with matched filters 1-1 to 1-3. Print each. An example of a detailed configuration of the matched filters 1-1 to 1-3 is as shown in FIG. For example, when sending digital data "0", K1 and K2 are output, and when sending digital data "1", K1 and K3 are output.

When the output signal K1 is transmitted from the delay time controller 2, the matched filter 1-1 outputs a reference pulse string signal P1 serving as a reference for data determination spread with the spread code PN0. The matching filter 1-2 receives the output signal K2 and outputs the data pulse string signal P2 spread by the spreading code PN1 slower by a predetermined time T than the reference signal. The matching filter 1-3 receives the output signal K3 and outputs the data pulse string signal P3 spread by the spreading code PN1 faster than the reference signal by a predetermined time T. Here, the spreading codes PN0 and PN1 have an orthogonal relationship with each other. These are added by the adder 3, amplified by a power amplifier (PA) 4, and then radiated through the antenna 6 as a pulse train signal P0.

In the receiver, the pulse train signal P0 received through the antenna 5 is amplified by a low noise amplifier (LNA) 7 and then output to the matching filters 8-1 and 8-2. An example of the matched filters 8-1 and 8-2 is shown in FIG. When the matching filter 8-1 corresponding to the spreading code PN0 detects the reference signal and the matching filter 8-2 corresponding to the spreading code PN1 detects the data signal, it outputs the correlated output signals S1 and S2, respectively. The delay time measuring device 9 detects which of the output correlation signals S1 and S2 is input first. The data determiner 10 demodulates the data signal based on the detection result of the delay time measurer 9. In this case, when the correlation output signal S2 is slow with respect to the correlation output signal S1, the data is "0". When the correlation output signal S2 is fast with respect to the correlation output signal S1, the data is "1".

By using the above technique, since the high speed band synchronization digital circuit is not required in the ultra wide band wireless communication system, the ultra wide band wireless communication can be performed by the low speed digital circuit with low power consumption and the influence of multipath. Can be suppressed.

However, when the large-capacity data such as a video signal is to be transmitted by using the ultra-wideband direct spread pulse communication method, it is necessary to speed up the data transfer rate per unit time. In order to make the transfer rate higher, it is necessary to shorten the pulse chip interval of the transmitted pulse train and to reduce the number of pulse chips, thereby shortening the time length of the transmitted pulse train P0.

However, in order to speed up the transmission rate, when the number of chips is reduced, the correlation outputs S1 and S2 of the matching filters 8-1 and 8-2 of the pulse string P0 in the receiver are mutually related to the spread pulse string signal of the other side. Because the correlation is not small enough, the D / U (Desired / Unwanted) ratio is deteriorated under the influence, the dynamic range at the time of 1-bit analog-to-digital (A / D) conversion is reduced, and BER (Bit Error) Problems that cause deterioration of the rate) occur.

Next, in order to clearly show this problem, the case of the Barker code (PN0: 1011000, PN1: 0001101) of 7 chips with a small number of chips well known and having good autocorrelation characteristics will be described. As shown in Fig. 15, the seven-chip Barker code has a large D / U ratio of 7 to 1 in autocorrelation characteristics. However, the ultra-wideband direct spread pulse communication method as shown in FIG. 16 is used for the seven-chip Barker code (components having substantially the same functional configuration as those in FIG. 12 are denoted by the same reference numerals, and redundant description is omitted. ), Since the cross-correlation property between the spreading codes PN0 and PN1 is not good, the D / U ratio deteriorates to 7 to 3 as shown in FIGS. 17 and 18. In order to improve the D / U ratio, it is necessary to improve the cross-correlation characteristics and use a long spreading code. However, in this case, it is difficult to realize a high data transfer rate.

Accordingly, the present invention provides a wireless transmitter using a spreading code having a good D / U ratio of a correlated output without increasing the number of chips in an ultra-wideband direct spread pulse communication method in which two series of data are transmitted and received using different spreading pulse sequences. Provide a wireless receiver.

The present invention for this purpose provides a wireless transmitter using an ultra-wideband direct spread pulse communication method. The wireless transmitter to which the present invention is applied generates a periodic pulse and outputs it to the first matching filter, and outputs the periodic pulse to the second matching filter when the transmission data is the first level of the two-value logic level. A delay time controller for outputting the periodic pulse to a third matching filter when the transmission data is at the second level of the two-value logic level, and if the periodic pulse is input, a first spreading code of chip number (2 * N-1) The first matched filter for outputting a reference signal as a reference for data determination and a second spreading code having a number of chips (2 * N-1) for a predetermined time from the reference signal when the periodic pulse is input. The second matched filter for quickly outputting the first data signal; and the third matched filter for outputting the second data signal slower than the reference signal by a predetermined time using the second spreading code when the periodic pulse is input. Equipped.

The (2 * N-2) th value and the (2 * N) th value of the cross-correlation signal between the first spreading code and the second spreading code are equal to or greater than 0, and the autocorrelation signal of the first spreading code The (2 * N-3) th value and the (2 * N + 1) th value are 0 or less, and the (2 * N-3) th value and (2 * N + 1) of the autocorrelation signal of the second spreading code ) Th value is 0 or less.

According to such a wireless transmitter, in an ultra-wideband direct spread pulse communication method in which two series of data are transmitted and received using different spreading code sequences, it is desirable to provide a spreading code having a good D / U ratio of a correlation output without increasing the number of chips. It is possible.

That is, when the first and second spreading codes of the present invention are used, the (2 * N-2) th and (2 * N) th values of the cross correlation signal between the first spreading code and the second spreading code are 0. From the above, when evaluating with the evaluation system for the ultra-wideband direct spread pulse communication method, the (2 * N-1) th value (also referred to as the value of D / U ratio of D / U ratio) of the cross-correlation signal is at least. It does not become small.

Also, since the (2 * N-3) th and (2 * N + 1) th values of the autocorrelation signals of the first and second spreading codes are 0 or less, the evaluation system for the ultra wideband direct spread pulse communication method is evaluated. In this case, the (2 * N-3) th value and the (2 * N + 1) th value (the value relating to U of the D / U ratio) of the cross-correlation signal do not at least become large. In addition, the detail of a correlation signal is mentioned later.

If the (2 * N-2) th value and the (2 * N) th value (the value relating to D of the D / U ratio) of the cross-correlation signal are 0 or more, at least the D / U ratio is not reduced. In particular, if it is 1 or more, the D / U ratio can be increased. Moreover, if it is two or more, it is more practical. Similarly, if the (2 * N-3) th value and the (2 * N + 1) th value (the value of U of the D / U ratio) of the autocorrelation signal of the first and second spreading codes are 0 or less, Although at least the D / U ratio is not reduced, in particular, if it is -1 or less, the D / U ratio can be increased, which is effective. In addition, below -2, it is more practical.

Various applications are possible in the radio transmitter which concerns on this invention. For example, the first to third matching filters can be a surface acoustic wave (SAW) filter. If the matching filter is composed of a surface acoustic wave device, signal processing can be performed without using complicated digital circuits, which is advantageous in terms of power consumption.

In addition, the diffusion code of the present invention has a large effect at N = 15 or less (2 * N-1 = 2 * 15-1 = 29 or less as the number of chips) which is difficult to obtain good cross-correlation characteristics.

In one example of the spreading code of the present invention, the first spreading code is “1, 1, 0, 0, -1, 1, 0, 1, 0, 0, 1, 0, -1”, or reverses it. One is "-1, 0, 1, 0, 0, 1, 0, 1, -1, 0, 0, 1, 1", and the second spreading code is "1, 1, 0, 0, 0, 0, 1, -1, 1, 0, -1, 0, 1 ”, or the reversed“ 1, 0, -1, 0, 1, -1, 1, 0, 0, 0, 0, 1, 1 ” to be. According to such a spreading code, it is possible to set the D / U ratio to a good value of 9: 2 or 10: 2. This point is mentioned later.

In addition, as another example of the spreading code of the present invention, the first spreading code may be “0, 1, 0, -1, 0, 1, 1, 0, 0, 0, -1, 1, -1”, or Inverted “-1, 1, -1, 0, 0, 0, 1, 1, 0, -1, 0, 1, 0”, and the second spreading code is “0, 1, 0, 0, 1, 1, 1, 0, -1, 0, 0, -1, 1 ”, or the reversed“ 1, -1, 0, 0, -1, 0, 1, 1, 1, 0, 0, 1, 0 ”. According to this spreading code, it is possible to set the D / U ratio to a good value of 9: 2 or 10: 2. This point is mentioned later.

According to another aspect of the present invention, there is provided a wireless receiver using an ultra-wideband direct spread pulse communication method. The radio receiver of the present invention receives an electric wave signal and outputs the antenna unit to the first matching filter and the second matching filter, and receives the signal from the antenna unit and detects a reference signal as a reference for data determination. The first matched filter for outputting the first output signal using the first spreading code of (2 * N-1) and the number of chips (2 * N-1) The second matching filter for outputting the second output signal using the second spreading code of?) And which one of the first output signal and the second output signal are first output from the first and second matching filters. A delay time measuring unit for detecting and outputting the detection result, and a data determination unit for receiving the detection result and determining whether the data signal is a first level or a second level of a two-value logic level.

The (2 * N-2) th value and the (2 * N) th value of the cross-correlation signal between the first spreading code and the second spreading code are equal to or greater than 0, and the autocorrelation signal of the first spreading code The (2 * N-3) th value and the (2 * N + 1) th value are 0 or less, and the (2 * N-3) th value and (2 * N + 1) of the autocorrelation signal of the second spreading code ) Th value is 0 or less.

According to such a wireless receiver, in the ultra-wideband direct spread pulse communication method in which two series of data are transmitted and received using different spreading pulse sequences, it is possible to provide a spreading code having a good D / U ratio of correlation output without increasing the number of chips. .

That is, when the first and second spreading codes of the present invention are used, the (2 * N-2) th and (2 * N) th values of the cross correlation signal between the first spreading code and the second spreading code are 0. From the above, when evaluating with the evaluation system for the ultra-wideband direct spread pulse communication method, the (2 * N-1) th value (also referred to as the value of D / U ratio of D / U ratio) of the cross-correlation signal is at least. It does not become small. The details of the correlation signal will be described later.

Also, since the (2 * N-3) th and (2 * N + 1) th values of the autocorrelation signals of the first and second spreading codes are 0 or less, the evaluation system for the ultra wideband direct spread pulse communication method is evaluated. In this case, the (2 * N-3) th value and the (2 * N + 1) th value (the value relating to U of the D / U ratio) of the cross-correlation signal do not become large at least.

If the (2 * N-2) th value and the (2 * N) th value (the value relating to D of the D / U ratio) of the cross-correlation signal are 0 or more, at least the D / U ratio is not reduced. Especially 1 or more can increase the D / U ratio, which is effective. Moreover, if it is two or more, it is more practical. Similarly, if the (2 * N-3) th value and the (2 * N + 1) th value (the value of U of the D / U ratio) of the autocorrelation signal of the first and second spreading codes are 0 or less, Although at least the D / U ratio is not reduced, especially -1 or less, it is effective because the D / U ratio can be increased. In addition, below -2, it is more practical.

In the radio receiver according to the present invention, various applications are possible. For example, the first and second matched filters can be a surface acoustic wave device. If the matching filter is composed of a surface acoustic wave device, signal processing can be performed without using complicated digital circuits, which is advantageous in terms of power consumption.

In addition, the diffusion code of the present invention has a large effect at N = 15 or less (2 * N-1 = 2 * 15-1 = 29 or less as the number of chips) which is difficult to obtain good cross-correlation characteristics.

As an example of the spreading code of the present invention, the first spreading code is “-1, 0, 1, 0, 0, 1, 0, 1, -1, 0, 0, 1, 1”, or “1 inverted”. , 1, 0, 0, -1, 1, 0, 1, 0, 0, 1, 0, -1 ”, and the second spreading code is“ 1, 0, -1, 0, 1, -1, 1 , 0, 0, 0, 0, 1, 1 ”, or inverted“ 1, 1, 0, 0, 0, 0, 1, -1, 1, 0, -1, 0, 1 ”. According to such a spreading code, it is possible to set the D / U ratio to a good value of 9: 2 or 10: 2. This point is mentioned later.

In addition, as another example of the spreading code of the present invention, the first spreading code is “-1, 1, -1, 0, 0, 0, 1, 1, 0, -1, 0, 1, 0”, or the inversion thereof. One is “0, 1, 0, -1, 0, 1, 1, 0, 0, 0, -1, 1, -1”, and the second spreading code is “1, -1, 0, 0, -1 , 0, 1, 1, 1, 0, 0, 1, 0 ”, or the reversed“ 0, 1, 0, 0, 1, 1, 1, 0, -1, 0, 0, -1, 1 "to be. According to such a spreading code, it is possible to set the D / U ratio to a good value of 9: 2 or 10: 2. This point is mentioned later.

According to another aspect of the present invention, there is provided a program for causing a computer to function as a radio transmitter or radio receiver according to the present invention, and a computer-readable recording medium on which the program is recorded. Here, the program may be described in any program language. As the recording medium, for example, a CD-ROM, a DVD-ROM, a flexible disk, or the like can be used as a recording medium which can be used for recording a program.

Hereinafter, a preferred embodiment of a radio transmitter and a radio receiver according to the present invention will be described with reference to the accompanying drawings. In the following description, since the overall device configuration is the same as that shown in Fig. 12 or 16, the redundant description will be omitted, and the description will be mainly focused on the difference from the background art. In addition, in this specification and drawing, duplication description is abbreviate | omitted by attaching | subjecting the same number about the component which has substantially the same functional structure.

In the case of a conventionally used diffusion code such as a Barker code or a Gold code, as shown in Fig. 16, the pulse string signal P1 generated by the diffusion code PN0 by the matching filter 1-1 and the matching filter 1-2 are shown. Is arranged so that each chip interval of the pulse string signal P2 generated by the spreading code PN1 and the pulse string signal P3 generated by the spreading code PN1 by the matching filter 1-3 is T '. The transmission pulse train signal P0 is transmitted with each chip of the pulse train signal P2 or P3 arranged between the chips of the pulse train signal P1.

In this case, since the correlation signal obtained by the receiver is output such that the correlation signal for P1 and the correlation signal of P2 or P3 are arranged between the chips of each other, the correlation signals of each other do not affect. Therefore, even if the autocorrelation property is good, the side lobe of the finally obtained correlation signal is determined as the cross-correlation signal level if the cross-correlation property is bad, resulting in deterioration of the D / U ratio compared to the auto-correlation property. If the number of chips is long, there is a code having good cross-correlation characteristics, but if the number of chips is limited, the communication quality will be deteriorated.

1A and 1B are explanatory diagrams showing an example of a test system for evaluating autocorrelation characteristics and cross-correlation characteristics. In Fig. 1A, the matching filter 1-1 on the transmitter side corresponds to the spreading code PN0. In Fig. 1B, matching filters 1-2 or 1-3 on the transmitter side correspond to spreading code PN1.

Fig. 2 shows autocorrelation characteristics and cross-correlation characteristics when a seven-chip Barker code (PN0: 1011000, PN1: 0001101) is evaluated by the test system of Fig. 1. Fig. 2A shows the autocorrelation signal S1-1 of the diffusion code PN0 in the matching filter 8-1. 2 (b) shows the cross-correlation signal S1-2 of the spreading codes PN0 and PN1 in the matching filter 8-1. Fig. 2C shows the cross-correlation signal S2-1 of the spreading codes PN0 and PN1 in the matching filter 8-2. 2 (d) shows the autocorrelation signal S2-2 of the spreading code PN1 in the matched filter 8-2. As shown in Fig. 2, the autocorrelation property has a good D / U ratio of 7: 1, but the cross-correlation property becomes 3 at the peak value.

3 is an explanatory diagram showing a method of calculating the correlation signal shown in FIG. In FIG. 3, the case of FIG. 2A will be described as an example. If REF (PN0) is input to the matching filter PN0 by one chip in one row, the correlation becomes -1 with 1 * (-1) = -1. In the second row, when REF (PN0) is input to the matching filter PN0 by two chips, the correlation becomes 0 with 1 * (-1) + (-1) * (-1) = 0. In the same way, when the correlation is calculated, in the seventh row, if REF (PN0) is input to the matching filter PN0 by seven chips, (-1) * (-1) + (-1) * (-1) + (-1) * (-1) + 1 * 1 + 1 * 1 + (-1) * (-1) + 1 * 1 = 7 and the correlation is 7. In this way, the correlation signals "-1, 0, -1, 0, -1, 0, 7, 0, -1, 0, -1, 0, -1" are calculated. In the following description, the calculation of the correlation signal is performed in the same manner as the method shown in Fig. 3, and the description of the details of the calculation is omitted.

4A and 4B are explanatory diagrams showing an example of an evaluation system for an ultra-wideband direct spread pulse communication method in an evaluation system for evaluating autocorrelation characteristics and cross-correlation characteristics. In Fig. 4A, the matching filter 1-2 at the transmitter side corresponds to the delay time [+ T]. In Fig. 4B, the matching filter 1-3 on the transmitter side corresponds to the delay time [-T].

FIG. 5 shows autocorrelation characteristics and cross-correlation characteristics when the seven chip number Barker codes are evaluated by the evaluation system for the ultra-wideband direct spread pulse communication method of FIG. 4. Fig. 5A shows the transmission pulse train signal P0 [+ T] of the delay time [+ T]. Fig. 5 (b) shows the transmission pulse train signal P0 [-T] of the delay time [-T]. Fig. 5C shows the correlation signal S1-3 between the transmission pulse string signal P0 [+ T] and the matching filter 8-1 of the spreading code PN0. Fig. 5 (d) shows the correlation signal S2-3 between the transmission pulse string signal P0 [+ T] and the matching filter 8-2 of the spreading code PN1. Fig. 5E shows the correlation signal S1-4 between the transmission pulse string signal P0 [-T] and the matching filter 8-1 of the spreading code PN0. Fig. 5 (f) shows the correlation signal S2-4 between the transmission pulse string signal P0 [-T] and the matching filter 8-2 of the spreading code PN1.

In FIG. 5, the underlined numbers indicate signals resulting from the reference pulse train signal P1 (REF). Otherwise, it corresponds to the data pulse string signal P2 or P3. As such, the final correlation signal is inserted between the autocorrelation pulse chips independently. Therefore, if the cross-correlation property is bad, the D / U ratio of the correlation signal deteriorates by that much.

In the present embodiment, as shown in Fig. 6, in the ultra-wideband direct spread pulse communication system, when each chip of the transmission pulse train signal P0 is arranged at the same interval at chip interval T (T '= 2 * T) Is adapted to Therefore, the delay time for data determination is T equal to the chip interval. In the conventional system, the pulse string signals P1 to P3 constituted by the chip interval T '= 2T and the number N of chips are extended to the pulse string signals of the chip interval T and the number of chips (2 * N-1). Since the added transmit pulse string signal P0 is the same number of chips, the data transfer rate is not degraded. In addition, the code value of each chip is selected from 3 values of -1, 0, 1. As a result, the reference pulse train signal P1 and the data pulse train signal P2 or P3 are not listed in the same period, respectively, so that the added transmit pulse train signal P0 has 5 values of -2, -1, 0, 1, 2, respectively. This results in amplitude modulation.

In the receiver, the correlation signal for the pulse train signal P1 and the correlation signal for P2 or P3 are not generated at positions independent of each other, because each chip is not arranged in the same period. Therefore, the correlation signals of each other affect. In this embodiment, this effect is achieved by actively accepting this effect.

In the two spreading codes PN0 'and PN1' of the number of chips (2 * N-1) according to the present embodiment, the (2 * N-2) th and (2 * N) th of the output cross-correlation signals have a value of 2 or more. Have The (2 * N-3) th and (2 * N + 1) th values of the autocorrelation signal of the spreading code PN0 'are 0 or less, and the (2 * N-3) th and ( The 2 * N + 1) th is also 0 or less.

As a result, the reference pulse string signal P1 'serving as a reference for the data determination spread by the matching filter 1-1 to the diffusion code PN0' is converted to the diffusion code PN1 'by the matching filter 1-2 or 1-3. Since each chip of the spread data pulse string signal P2 'or P3' is spaced apart by ± T, the peak value in the (2 * N-1) th position of the autocorrelation signal is (2 * N-2) The (th) or (2 * N) th values (two or more) are added to each other to increase the peak value of the correlation signal.

In addition, the (2 * N-1) th value of the autocorrelation signal and the (2 * N-2) th or (2 * N) th value of the cross-correlation signal of one side not added are the (2 * N-) th values of the autocorrelation signal. It is added with the 3) th and (2 * N + 1) th values, but this value becomes small because it is a value of 0 or less. By using the spread codes PN0 'and PN1' as described above, the peak value of the correlation signal can be increased without deteriorating the value of the side lobe of the correlation signal. Therefore, the D / U ratio can be increased, and the data transfer rate can be increased while maintaining the communication quality.

Taking the case where N = 7, the spreading code of the transmission / reception system according to the present embodiment will be described. Autocorrelation characteristics and cross-correlation characteristics when evaluated by the test system of FIG. 1 are shown in FIG. Fig. 7A shows the autocorrelation signal S1-1 of the diffusion code PN0 'in the matched filter 8-1. Fig. 7 (b) shows the cross-correlation signal S1-2 of the spreading codes PN0 'and PN1' in the matching filter 8-1. Fig. 7C shows the cross-correlation signal S2-1 of the spreading codes PN0 'and PN1' in the matched filter 8-2. Fig. 7 (d) shows the autocorrelation signals S2-2 of the diffusion codes PN0 'and PN1' in the matched filter 8-2.

FIG. 8 shows the results of evaluation by the evaluation system for the ultra-wideband direct spread pulse communication method shown in FIG. 4. Fig. 8A shows the transmission pulse train signal P0 [+ T] of the delay time [+ T]. Fig. 8B shows the transmission pulse string signal P0 [-T] of the delay time [-T]. Fig. 8C shows a correlation signal S1-3 between the transmission pulse string signal P0 [+ T] and the matching filter 8-1 of the spreading code PN0 '. Fig. 8 (d) shows the correlation signal S2-3 between the transmission pulse string signal P0 [+ T] and the matching filter 8-2 of the spreading code PN1 '. Fig. 8E shows the correlation signal S1-4 between the transmission pulse string signal P0 [-T] and the matching filter 8-1 of the spreading code PN0 '. Fig. 8F shows a correlation signal S2-4 between the transmission pulse string signal P0 [-T] and the matching filter 8-2 of the spreading code PN1 '.

In Figs. 7 and 8, numerals in " " are emphasized for easy combination of peak value portions of the final correlation output signal. In an embodiment of the present invention, the "correlation signal S1-1 and the cross-correlation signal S1-2", the "correlation signal S1-1 and the cross-correlation signal S2-1", and the "correlation of the self-correlation signal S2-2" Correlation output signals of four types of combinations of signals S1-2 ", " self-correlation signal S2-2 and cross-correlation signal S2-1 " are output from the matching filter. However, the resulting peak value 9 (or 10) is obtained by adding 7 and 2 (or 7 and 3) of each autocorrelation and cross-correlation.

As shown in Fig. 8, the D / U ratio in the case of P0 [+ T] is 9: 2 (in this system, the side lobe signal in the slow time range can be ignored) and P0 [-T] is The D / U ratio in this case was 10: 2, showing good values. Therefore, by using the spreading code according to the present embodiment, a remarkable improvement can be achieved as compared with the case of using a spreading code known in the art.

In practice, a spreading code having autocorrelation characteristics satisfying the above-described conditions is calculated for N determined from the required data transfer rate, and two of them are selected to extract a combination that satisfies the above cross-correlation characteristics.

9 shows an example of another spreading code. 9 (a) shows spreading codes PN0 (TX) and PN1 (TX) applied to the matching filter on the transmitter side. 9 (b) shows spreading codes PN0 (RX) and PN1 (RX) applied to the matching filter on the receiver side. Alternatively, a reversed spread code shown in FIG. 9 may be used. For example, for PN0 (TX) = “0, 1, 0, -1, 0, 1, 1, 0, 0, 0, -1, 1, -1”, the inverted code is “- 1, 1, -1, 0, 0, 0, 1, 1, 0, -1, 0, 1, 0 ”may be used. The code inverting this corresponds to PN0 (RX).

10 and 11 show the results of evaluating the spreading code of FIG. 9 with the evaluation system for the ultra-wideband direct spread pulse communication method shown in FIG. 4. As shown in Fig. 10, the D / U ratio in the case of P0 [+ T] is 10: 2 (in this system, the side lobe signal in the slow time range can be ignored), and P0 [-T] As shown in FIG. 11, the D / U ratio in this case was 9: 2, and all showed favorable values. Therefore, by using the spreading code shown in Fig. 9, a remarkable improvement can be achieved as compared with the case of using a spreading code known in the prior art.

While the preferred embodiments of the radio transmitter and radio receiver according to the present invention have been described with reference to the accompanying drawings, the present invention is not limited to these examples. Those skilled in the art will understand that various changes or modifications can be made within the scope of the technical idea described in the claims, and those of course belong to the technical scope of the present invention.

For example, in the above embodiment, the (2 * N-2) th value and the (2 * N) th value of the cross correlation signal between the first spreading code PN0 'and the second spreading code PN1'. Although the case where this is 0 or more was demonstrated, you may make a (2 * N-3) th value and a (2 * N + 1) th value 0 or more. Alternatively, the (2 * N-4) th value and the (2 * N + 2) th value may be equal to or greater than zero. In other words, it is possible to set any value of the left-right symmetry (the position spaced ± T apart) to 0 or more, centering on the (2 * N-1) th value (peak value) for determining D of the D / U ratio. . In this way, the delay time T can be shifted and the data can be multiplexed further.

In the above embodiment, a configuration in which only two matching filters (1-2 and 1-3) for providing a delay time is provided on the transmitter side has been described, but more matching filters may be provided. In this case, the spreading code can be appropriately optimized according to the number of matching filters, the delay time, or the like.

In the above embodiment, the two spreading codes PN0 'and PN1' having the number of chips (2 * N-1) are the (2 * N-2) th and (2 * N) th of the output cross correlation signals. Although the case which has the above value was demonstrated, this invention is not limited to this. If it is 0 or more, at least D / U ratio is not reduced. Moreover, if it is 1 or more, it is effective because a D / U ratio can be enlarged.

In the above embodiment, the two spreading codes PN0 'and PN1' of the number of chips (2 * N-1) are the (2 * N-3) th and (2 * N + 1) of the autocorrelation signal of the spreading code PN0 '. Although the () th value is 0 or less, and the (2 * N-3) th and (2 * N + 1) th of the autocorrelation signal of the spreading code PN1 'are also 0 or less, the present invention is not limited thereto. Do not. If it is less than -1, it is effective because D / U ratio can be increased. Moreover, if it is -2 or less, it is more practical.

In addition, the wireless transmitter or the wireless receiver described in the above embodiment can combine the computer program for realizing the above functions in the computer, and can make the computer function as the wireless transmitter or the wireless receiver. Such a computer program can be distributed to the market in a form recorded on a predetermined recording medium (for example, CD-ROM) or in a download form through an electronic network.

According to the present invention as described above, in the ultra-wideband direct spread pulse communication method in which two series of data are transmitted and received using different spreading pulse sequences, the D / U ratio of the correlation output can be improved without increasing the number of chips. There is an advantage to that.

Claims (10)

In the ultra-wideband direct spread pulse communication wireless transmitter, Generates a periodic pulse and outputs it to the first matched filter, and outputs the periodic pulse to the second matched filter when the transmission data is at the first level of the two-value logic level, and transmits the data to the second matched logic level. A delay time controller for outputting the periodic pulse to a third matched filter when the level is 2; The first matched filter for outputting a reference signal as a reference for data determination by using a first spreading code having a number of chips (2 * N-1) when the periodic pulse is inputted; The second matched filter outputting the first data signal faster by the predetermined time than the reference signal by using the second spreading code having the number of chips (2 * N-1) when the periodic pulse is input; And a third matched filter for outputting a second data signal by a predetermined time later than the reference signal by using the second spreading code when the periodic pulse is input, The (2 * N-2) th value and the (2 * N) th value of the cross-correlation signal between the first spreading code and the second spreading code are 0 or more, (2 * N-3) th value and (2 * N + 1) th value of the autocorrelation signal of the first spreading code are 0 or less, And the (2 * N-3) th value and the (2 * N + 1) th value of the autocorrelation signal of the second spreading code are zero or less. The method of claim 1, The first spreading code is “1, 1, 0, 0, -1, 1, 0, 1, 0, 0, 1, 0, -1”, or “-1, 0, 1, 0 inverting it”. , 0, 1, 0, 1, -1, 0, 0, 1, 1 ”, The second spreading code is “1, 1, 0, 0, 0, 0, 1, -1, 1, 0, -1, 0, 1”, or “1, 0, -1, 0 inverting it”. , 1, -1, 1, 0, 0, 0, 0, 1, 1 ”. The method of claim 1, The first spreading code is “0, 1, 0, -1, 0, 1, 1, 0, 0, 0, -1, 1, -1”, or “-1, 1, -1 inverting it”. , 0, 0, 0, 1, 1, 0, -1, 0, 1, 0 ”, The second spreading code is “0, 1, 0, 0, 1, 1, 1, 0, -1, 0, 0, -1, 1”, or “1, -1, 0, 0 inverting it”. , -1, 0, 1, 1, 1, 0, 0, 1, 0 ”. The radio transmitter of claim 1, wherein N is 15 or less. The radio transmitter according to any one of claims 1 to 4, wherein the first to third matching filters are surface acoustic wave devices. In the ultra-wideband direct spread pulse communication wireless receiver, An antenna unit for receiving a radio signal and outputting the first matching filter and the second matching filter; The first signal outputting the first correlation output signal using the first spreading code of the number of chips (2 * N-1) when receiving a signal from the antenna unit and detecting a reference signal as a reference for data determination. Matching filter, Receiving the signal from the antenna unit and detecting a data signal, outputting a second correlation output signal using a second spreading code having a number of chips (2 * N-1); A delay time measuring unit for detecting which of the first correlation output signal and the second correlation output signal are first output from the first and second matching filters, and outputting the detection result; A data determination unit which receives the detection result and determines whether the data signal is a first level or a second level of a two-value logic level, The (2 * N-2) th value and the (2 * N) th value of the cross-correlation signal between the first spreading code and the second spreading code are 0 or more, (2 * N-3) th value and (2 * N + 1) th value of the autocorrelation signal of the first spreading code are 0 or less, And the (2 * N-3) th value and the (2 * N + 1) th value of the autocorrelation signal of the second spreading code are zero or less. The method of claim 6, The first spreading code is “-1, 0, 1, 0, 0, 1, 0, 1, -1, 0, 0, 1, 1”, or “1, 1, 0, 0, -1, 1, 0, 1, 0, 0, 1, 0, -1 ”, The second spreading code is “1, 0, -1, 0, 1, -1, 1, 0, 0, 0, 0, 1, 1”, or “1, 1, 0, 0, 0, 0, 1, -1, 1, 0, -1, 0, 1 ”. The method of claim 6, The first spreading code is “-1, 1, -1, 0, 0, 0, 1, 1, 0, -1, 0, 1, 0”, or “0, 1, 0,-inverted thereof”. 1, 0, 1, 1, 0, 0, 0, -1, 1, -1 ”, The second spreading code is “1, -1, 0, 0, -1, 0, 1, 1, 1, 0, 0, 1, 0”, or “0, 1, 0, 0, 1, 1, 1, 0, -1, 0, 0, -1, 1 ”. 7. The radio receiver of claim 6 wherein N is 15 or less. The wireless receiver according to any one of claims 6 to 9, wherein the first to second matching filters are surface acoustic wave devices.

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