JPH114182A - Radio communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device which can attain a communication system that has a large circuit capacity and also can secure the privacy. SOLUTION: A radio communication device 10 has two spread spectrum communication devices of the same occupied frequency bands of FH(frequency hopping) and DS(direct spread) systems and selects one of both communication devices that has a smaller error rate when the communication is started. Then a receiving circuit of the FH system includes an S/N enhancer 14 which uses an magnetostatic wave device and is placed at the preceding stage of an FH inverse diffuser 15. Meanwhile, a receiving circuit of the DS system includes a threshold filter 16 which uses a magnetostatic wave device and is placed at the preceding stage of a DS inverse diffuser 17. Thus, it's possible to secure the privacy, to increase the number of circuits and to decrease the interference between both systems for improvement of the circuit quality by using simultaneously two spread spectrum communication systems under the condition where the occupied frequency bands are overlapping with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication apparatus, and more particularly to a radio communication apparatus in a radio communication system in which two spread spectrum communications of a frequency hopping scheme and a direct spread scheme are simultaneously used in the same occupied frequency band.

[0002]

2. Description of the Related Art Conventionally, there are spread spectrum communication systems of a frequency hopping system and a direct spread system for the purpose of increasing confidentiality and line capacity. Further, in order to further increase the frequency use efficiency, a communication system in which two communication systems, a spread spectrum communication system and a non-spread spectrum communication system, are used simultaneously in the same occupied frequency band is being studied.

[0003]

However, when two communication systems, that is, a spread spectrum communication system and a non-spread spectrum communication system are used at the same time, there is a problem that the non-spread spectrum communication system cannot realize sufficient privacy. is there.

Accordingly, the present invention provides a radio communication apparatus for realizing a communication system having a large line capacity and securing secrecy.

[0005]

In order to achieve the above object, a wireless communication apparatus according to the present invention is provided with two spread spectrum communication apparatuses having the same occupied frequency band of a frequency hopping scheme and a direct spread scheme at the start of communication. It is characterized by having a control circuit for selecting the spread spectrum communication apparatus of a scheme with a small error rate.

Further, in the radio communication apparatus according to the present invention, the frequency hopping type spread spectrum communication apparatus is characterized in that an S / N enhancer using a magnetostatic wave device is provided in front of a despreader on a receiving side. I do.

Further, the radio communication apparatus according to the present invention is characterized in that the direct spread type spread spectrum communication apparatus is provided with a threshold filter using a magnetostatic wave device in front of a despreader on the receiving side. .

[0008]

FIG. 1 shows an example of a wireless communication system using a wireless communication apparatus of the present invention. In FIG.
1 represents a base station, and 2 to 6 represent mobile stations.
Wireless communication is performed between the base station 1 and the mobile stations 2 to 6. As a method of wireless communication, frequency hopping (Frequency Hop) is performed in the same occupied frequency band.
ping, hereinafter abbreviated as FH), and direct diffusion (Di)
(Rect Sequence, hereinafter abbreviated as DS). FIG.
Represents a communication situation at a certain moment. Communication between the base station 1 and the mobile stations 2, 4 and 5 is performed by the FH method, and communication between the base station 1 and the mobile stations 3 and 6 is performed by the DS method. Is being done.

In general, in a spread spectrum communication system, a signal on one line becomes noise on all other lines existing in the same occupied frequency band. If the total number of lines is small, the adverse effects of other lines (interference)
Is small, but as the total number of lines increases, the energy density of noise increases and interference cannot be ignored.

[0010] Here, in the case of the spectrum distribution in the DS system, the level near the center frequency is the highest in the occupied frequency band, and the levels on both sides are relatively low. Therefore, the presence of noise on both sides of the occupied frequency band does not significantly affect communication. On the other hand, in the case of the FH system, the spectrum distribution has a substantially uniform level over the entire occupied frequency band. Therefore, even if the two methods are mixed, near the center frequency of the occupied frequency band,
The DS system has a higher energy density than the FH system, and conversely, on both sides, the FH system has a higher energy density than the DS system. Therefore, rather than increasing the number of DS system lines and increasing the local energy density to increase interference between the lines, it is possible to reduce interference by mixing both systems and lowering the overall energy density. . And the number of lines can be increased as compared with the case where only one method is used.

[0011] When communication is started between the base station and one mobile station, which of the two spread spectrum communication systems is adopted depends on the communication situation of the two systems at that time. In other words, check the status of the communication line in advance, determine which method is the one with the lower error rate of the communication data, select the method that is determined to have the lower error rate at that point, set the line, and perform communication. Start.

Thus, the occupied frequency bands are the same,
By performing communication by selecting two spread spectrum communication systems, the FH system and the DS system, according to the situation, either one of the spread spectrum communication systems is adopted, or the spread spectrum communication system and the non-spread spectrum communication method are used. Compared with the case where the methods are combined, secrecy can be secured, the number of lines can be increased, and the quality of the lines can be improved.

FIG. 2 shows an embodiment of the wireless communication apparatus according to the present invention. FIG. 2 is a block diagram illustrating a circuit on the receiving side of the base station or the mobile station. In FIG. 2, the wireless communication device 1
0 is the antenna 11, amplifier 12, switch 13, S /
N enhancer 14, FH despreader 15, threshold filter 16, DS despreader 17, switch 18, demodulator 1
9. It is composed of a control circuit 20. Here, the antenna 11 is connected to the switch 13 via the amplifier 12. One of the two outputs of the switch 13 is connected to one input of a switch 18 via an S / N enhancer 14 and an FH despreader 15 in order, and the other output is a threshold filter 16 and a DS despreader. Switch 1 through 17 in order
8 is connected to another input. The output of the switch 18 is connected via a demodulator 19 to a signal processing circuit (not shown). Then, the control circuit 20 controls the switch 13
And 18 control terminals. Here, the circuit on the transmission side is omitted.

In the wireless communication apparatus 10 configured as described above, a signal received by the antenna 11 is amplified by the amplifier 12 and input to the switch 13. The switch 13 is switched by the control circuit 20 according to the communication method of the signal to be received, and the signal input to the switch 13 is sent to the S / N enhancer 14 when the signal to be received is an FH signal, The case is input to the threshold filter 16. At this time, the received signal includes a plurality of signals of the FH system and the DS system in addition to the signal to be received.

Here, the power of each FH signal is concentrated on a specific frequency when a certain moment is captured, and the level thereof is controlled by the system so as to be larger than the sum of the DS signals at that frequency. . Note that DS
If the signal also captures a very short moment, power concentrates on a specific frequency like the FH signal, but the frequency change speed is sufficiently faster than the FH signal, so the FH signal concentrates on the specific frequency. It appears to be diffused within a certain amount of time. FIG. 3 shows the spectrum distribution of the signal output from the amplifier 12 at a certain moment. In FIG. 3, the horizontal axis represents frequency, the vertical axis represents signal level, and h represents FH.
And d represents a DS signal. Here, s represents a threshold level of the S / N enhancer 14 and the threshold filter 16 described later.

First, when the signal to be received is an FH signal,
The signal amplified by the amplifier 12 is transmitted through the switch 13 to S
/ N is input to the enhancer 14. S / N enhancer 1
4, a magnetostatic wave device is used, and a signal having a level lower than the threshold value s is suppressed. S / N
FIG. 4 shows the spectrum distribution of the signal output from the enhancer 14. As shown in FIG. 4, the level of the DS signal d2 lower than the threshold s is suppressed, and the level difference between the FH signal h and the DS signal d2 is widened. The signal whose DS signal level has been suppressed by the S / N enhancer 14 is FH
The signal is despread by the despreader 15. At this time, since the level of the DS signal is suppressed by the S / N enhancer 14, the S / N ratio of the signal to be received after despreading is improved. The signal despread by the FH despreader 15 is input to a demodulator 19 via a switch 18, demodulated, and input to a signal processing circuit (not shown). The switch 18
Is controlled by the control circuit 20 so as to be linked with the switch 13.

Conversely, when the signal to be received is a DS signal,
The signal amplified by the amplifier 12 is input to the threshold filter 16 via the switch 13. Threshold filter 1
6, a magnetostatic wave device is used, and a signal whose level is higher than the threshold s is limited to the level of the threshold s. The state is shown in FIG. As shown in FIG. 5, the level of the FH signal h2 higher than the threshold s is limited to the level of the threshold s, and the level difference between the FH signal h2 and the DS signal d is reduced. The signal whose FH signal level is limited by the threshold filter 16 is D
It is despread by the S despreader 17. At this time, since the level of the FH signal is limited by the threshold filter 16, the S / N ratio of the signal to be received after despreading is improved. The signal despread by the DS despreader 17 is input to a demodulator 19 via a switch 18, demodulated, and input to a signal processing circuit (not shown).

As described above, according to the radio communication apparatus 10, the S / N enhancer using the magnetostatic wave device is provided in the front stage of the FH despreader in the FH receiving circuit,
By providing a threshold filter using a magnetostatic wave device in the preceding stage of the DS despreader in the receiving circuit of the system,
Regardless of whether the signal to be received is an FH signal or a DS signal, mutual interference can be reduced and reception with a good S / N ratio can be performed.

[0019]

According to the radio communication apparatus of the present invention, one of the two spread spectrum communication systems of the same occupied frequency band of the FH system and the DS system is selected according to the situation and communication is performed. Securing confidentiality, increasing the number of lines,
The quality of the line can be improved.

In the FH receiving circuit of the radio communication apparatus, an S / N enhancer using a magnetostatic wave device is provided in front of the FH despreader, and in the DS receiving circuit, a magnetostatic wave is provided in front of the DS despreader. By providing a threshold filter using a device, even if a signal to be received is an FH signal or a DS signal, mutual interference can be reduced and reception with a good S / N ratio can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a wireless communication system using a wireless communication device of the present invention.

FIG. 2 is a block diagram showing one embodiment of a wireless communication device of the present invention.

FIG. 3 is a diagram illustrating a spectrum distribution of a signal output from an amplifier in the wireless communication device of the present invention.

FIG. 4 is a diagram illustrating a spectrum distribution of a signal output from an S / N enhancer in the wireless communication device of the present invention.

FIG. 5 is a diagram illustrating a spectrum distribution of a signal output from a threshold filter of the wireless communication device of the present invention.

[Description of Signs] 1 ... Base station 2, 3, 4, 5, 6 ... Mobile station 10 ... Wireless communication device 11 ... Antenna 12 ... Amplifier 13 and 18 ... Switch 14 ... S / N enhancer 15 ... FH despreader 16 Threshold filter 17 DS despreader 19 Demodulator 20 Control circuit

Claims (3)

[Claims] 1. An apparatus comprising: two spread spectrum communication apparatuses having the same occupied frequency band of a frequency hopping scheme and a direct spread scheme; and a control circuit for selecting the spread spectrum communication apparatus of a scheme having a low error rate at the start of communication. A wireless communication device characterized by the following. 2. The frequency hopping spread spectrum communication apparatus according to claim 1, wherein an S / N enhancer using a magnetostatic wave device is provided at a stage preceding a despreader on the receiving side. Wireless communication device. 3. The radio according to claim 1, wherein the direct spread type spread spectrum communication apparatus is provided with a threshold filter using a magnetostatic wave device in front of a despreader on the receiving side. Communication device.