JPH0637762A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To realize the radio communication system newly by implementing radio communication without giving adverse effect such as interference or disturbance onto an inside of a radio area of an existing radio system and utilizing a desired frequency band. CONSTITUTION:A radio communication terminal equipment TU is provided with a 1st carrier detection circuit 32, a radar operation discrimination section 23c, a 2nd carrier detection circuit 33 and a radar interference discrimination section 23d in addition to a 3rd carrier detection circuit 34 required for transmission of a radio packet according to the CSMA system, the 1st carrier detection circuit 32 and the radar operation discrimination section 23c are used to discriminate whether or not a radar system RSM uses a radio channel, and the 2nd carrier detection circuit 33 and the radar interference discrimination section 23d are used to discriminate whether or not there is any possibility of giving cross modulation to the radar system RSM and the use of the radio channel is controlled based on the discrimination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a wireless LAN (local ar
wireless communication device used in a wireless communication system such as an ea netwoak) system, and in particular, a wireless system used to perform wireless communication by sharing the wireless channel within the wireless area of an existing wireless system such as a radar system. Regarding a communication device.

[0002]

2. Description of the Related Art In recent years, various wireless communication systems have been proposed with the increase of communication needs and the development of wireless communication technology, and one of them is a wireless LAN system. This wireless L
The AN system wirelessly transmits data between terminal devices such as a host computer, a personal computer, a printer, and an electronic file device in a relatively limited service area such as an office building or an office.

Incidentally, the data transmission rate of this type of system is, for example, IEEE802.3 CSMA /
As represented by the CD system, a speed of 10 Mbps or more is desired, and several tens of M is required to realize this transmission speed.
A bandwidth of Hz or higher is required. Also, this type of wireless L
The frequency band for realizing the AN system is 3 GHz or less because the free space loss is small to reduce the power consumption of the wireless device and the silicon device can be used to reduce the cost of the wireless device. The quasi-microwave band of is preferred. However, in the quasi-microwave band, most of the frequencies have already been allocated to other existing systems, and there is no room for newly allocating a band of several tens of MHz or more for the wireless LAN system.

[0004]

As described above, the wireless LA
Even if an attempt is made to implement a new wireless communication system such as the N system, there is currently no suitable frequency band available, which makes it difficult to realize a new wireless communication system.

The present invention has been made in view of the above circumstances, and an object thereof is to enable wireless communication without adversely affecting an existing wireless system such as interference and cross modulation. Thus, it is possible to provide a wireless communication device capable of realizing a new wireless communication system by using a desired frequency band.

[0006]

In order to achieve the above object, the wireless communication apparatus of the present invention comprises a first judging means and a second judging means for knowing the state of the wireless channel, and the first judging means. The means receives the radio signal transmitted through the radio channel, determines the usage state of the radio channel by the existing first radio system based on the reception result, and further determines the second determination means by the second determination means. Even when the wireless signal transmitted via the wireless channel is received and the wireless signal is transmitted using the wireless channel other than the wireless channel based on the reception result, the wireless signal is mixed with the first wireless system. It is determined whether there is a possibility of applying modulation. Then, when the radio channel use control means determines that the radio channel is in a state in which it can be considered to be in use by the first determination means, the use of the radio channel is avoided, and the second determination means. By the first
When it is determined that cross-modulation may be applied to the wireless system, the processing for avoiding the use of all wireless channels is executed.

Further, according to the present invention, in the first judging means,
Comparing the signal level of the radio signal transmitted through the selected radio channel with a predetermined first threshold level by the comparing means, and comparing the signal length of the transmitted radio signal and the periodicity of the signal. Of at least one of the signal levels detected by the detection means and selectively using the comparison result of the signal levels by the comparison means and the detection result of the signal length or the periodicity of the signal by the detection means, It is also characterized by determining whether or not the wireless channel is used.

At this time, the first threshold level is set so that the radio signal transmitted by the device itself is received with a predetermined margin with respect to the minimum reception sensitivity level assumed in the first radio system. Good to do.

Further, according to the present invention, in the second judging means, the signal level of the radio signal transmitted via the selected radio channel is set to a predetermined second threshold different from the first threshold level. While comparing with the value level by the comparing means, at least one of the signal length and the periodicity of the signal of the transmitted wireless signal is detected by the detecting means, and the comparison result of the signal level by the comparing means and the detecting means are detected. It is also characterized in that the signal length or the detection result of the periodicity of the signal is selectively used to determine whether or not there is a possibility of giving cross modulation to the first wireless system.

In this case, the second threshold level has a predetermined margin with respect to the minimum received signal level at which it is assumed that the radio signal transmitted by the device itself will undergo intermodulation in the first radio system. It is recommended to set it so that it is received with.

[0011]

As a result, according to the present invention, as a result of judging the use state of the wireless channel by the first judging means, the existing first
If it can be considered that this wireless system is using this wireless channel, wireless communication using this wireless channel is avoided. Therefore, despite using the common wireless channel in the common wireless area with the existing wireless system, the new second wireless system is operated without adversely affecting the existing wireless system such as interference. It becomes possible.

Further, even when it is determined that the first wireless system is not using the wireless channel, the self-device is the first
When the wireless communication device of the first wireless system is located in the vicinity of the wireless communication device, the wireless transmission of the device itself may cause interference due to intermodulation in the wireless communication device of the first wireless system. However, according to the present invention, as a result of determining the state of the wireless channel by the second determining unit, even when the wireless signal is transmitted using a wireless channel other than the wireless channel, the first wireless system is subjected to cross modulation. , The use of all radio channels is avoided. Therefore, it is possible to surely prevent the defect that causes the interference interference due to the intermodulation in the existing first wireless system.

Therefore, according to the present invention, a new wireless communication system such as a wireless LAN system can be easily realized by utilizing a frequency band such as a quasi-microwave band in which a new frequency cannot be assigned. It will be possible.

Further, according to the present invention, when determining whether or not the first wireless system can regard the wireless channel as being in use, and whether there is a possibility of giving cross modulation to the first wireless system. In determining the reception level of the wireless signal, at least one of the signal length and the periodicity is detected, and the reception level determination result and the detection result of the signal length or the periodicity are selectively detected. Is used to make a determination. Therefore, the first wireless system sends a wireless signal having a high peak output level like a wide area radar system, and a device for sending a wireless signal other than the first wireless system exists at a close range. If not, it is possible to determine the usage state of the wireless channel by the first wireless system based only on the received signal level of the wireless signal. In addition, even when there is a device that transmits a radio signal other than the first radio system in a close range, by detecting the signal length or periodicity of the radio signal, the radio signal of the system other than the first radio system can be detected. The influence is reduced, which makes it possible to more stably and reliably determine the usage state of the wireless channel by the first wireless system without causing an erroneous determination.

[0015]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 shows a wireless L according to an embodiment of the present invention.
It is the schematic which shows the arrangement | positioning relationship of an AN system and the existing radar system.

The radar system RSM has one radar base station RBS, and a radar radio area ER corresponding to the transmission power of the radar base station RBS is formed in a predetermined area centered on the radar base station RBS. . In this radar radio area ER, a plurality of wireless LAN systems (in the figure, 3
System) LSM1 to LSM3 are installed. These wireless LAN systems LSM1 to LSM3 are so-called evenly distributed wireless LAN systems, and each has a plurality of wireless communication terminal devices TU11 to TU14, T.
It houses U21 to TU23 and TU31 to TU34. The evenly distributed wireless LAN system does not have a centralized control station in the system, and each wireless communication terminal device autonomously performs control for communication so that direct wireless data communication is performed between the wireless communication terminal devices. It is a system to do. The connection between the respective wireless LAN systems LSM1 to LSM3 is performed by any wireless communication terminal device TU14, TU23,
This is performed by connecting the TU 31 via the wire line WL.

By the way, each of the wireless communication terminal units TU11 to TU11
TU14, TU21 to TU23, TU31 to TU34
(Hereinafter referred to as TU) is, for example, a host computer,
A personal computer, a printer, or an electronic file device is used as a terminal device body, and is configured as follows. FIG. 2 is a circuit block diagram showing the configuration of the main part thereof. That is, the wireless communication terminal unit TU includes a terminal device body 10 and a wireless LAN attached to the terminal device body 10.
It is composed of an adapter 20. The terminal body 10 is a CP
It has a configuration necessary for creating and storing packet data such as U11 and memory 12.

The wireless LAN adapter 20 is provided with a bus interface (I / F) 21 for transferring packet data to and from the terminal device body 10 and transfers from the terminal device body 10 via the bus interface 21. The transmitted transmission packet data is temporarily stored in the buffer memory 22 and then input to the transmission control unit 23a of the access controller 23. When the transmission packet data TD is input, the transmission controller 23a of the access controller 23 supplies the transmission packet data TD and the transmission clock TCK to the modulation circuit (MOD) 24 together with the carrier switch signal CSW.

The modulation circuit 24 first performs an error correction coding process on the transmission packet data SD. And
The error correction coded transmission packet data TD is set to 3
Divide and input to three different modulators. These modulators modulate three carrier waves f1 to f3 having different frequencies according to the transmission packet data divided into three parts. The modulation circuit 24 also generates parity information based on the transmission packet data divided into three parts, and inputs this parity information to another modulator. The modulator modulates the fourth carrier f4 according to the parity information. These 4
The modulated carrier signals output from the two modulators are combined and then input to the transmission power amplifier 26. The transmission power amplifier 25 amplifies the four-wave combined modulated carrier signal to a transmission level defined by the system. At this time, the transmission level is set to 2.5 mW / carrier, for example. Therefore, the modulated carrier signal obtained by combining the four waves as described above has a total output of 10 mW. The four-wave combined modulated carrier signal output from the transmission power amplifier 25 is supplied to an antenna 27 via a circulator 26, and from this antenna 27, another wireless communication terminal device T in the system.
Wirelessly transmitted to U. The carrier switch signal CSW is a signal for blocking the output of the modulated carrier wave signal from the modulation circuit 24 during the period when the carrier wave need not be transmitted.

On the other hand, the four-wave combined modulated carrier signal received by the antenna 27 is sequentially input to the low noise amplifier 29 and the band pass filter 30 after passing through the circulator 26 and the high frequency switch (SW) 28. The low noise amplifier 29 amplifies the received radio signal to a signal level required for demodulation processing. In the band pass filter 30,
Only the radio frequency component in the predetermined band is extracted. The high-frequency switch 28 is provided to prevent the transmission radio signal reflected by the antenna 27 from sneaking into the reception system during transmission, and conducts only during the reception period according to the control signal output from the access controller 23.

The four-wave synthesized modulated carrier signal output from the band pass filter 30 is demodulated by the demodulation circuit (DEM) 3
1, the first carrier detection circuit (CS1) 32, the second carrier detection circuit (CS2) 33, and the third carrier detection circuit (CS3) 34, respectively. The demodulation circuit 31 first separates the four-wave combined modulated carrier signal into carrier waves and demodulates them. Then, the four received baseband signals obtained by this demodulation are subjected to error correction decoding processing to reproduce the received packet data, and
Correct reception packet data RD is reproduced by combining these four reception packet data and performing error detection / correction calculation such as parity calculation. Further, the reception clock RCK is reproduced in the process of reproducing the reception packet data RD. Then, the demodulation circuit 31 supplies the regenerated reception packet data RD and the reception clock RCK to the reception control unit 23b of the access controller 23. The reception controller 23b of the access controller 23 generates reception packet data to be transferred to the terminal device body 10 based on the reception packet data RD and the reception clock RCK. Then, the received packet data is transferred to the terminal device body 10 via the bus interface 21.

The first carrier detection circuit 32 detects the radar pulse signal transmitted from the radar base station RBS of the radar system RSM in order to determine whether or not the radio channel is used by the radar system, and the received carrier wave. The level of the signal is compared with the preset first carrier detection level CSL1. Then, during the period in which the received carrier signal having a level higher than the first carrier detection level CSL1 is detected, the first detection signal CSS is detected.
1 is generated and supplied to the access controller 23.

Here, the first carrier detection level C
SL1 is set as follows, for example. That is, suppose that the transmission output of the radar base station RBS is 500 kW to 20
00 kW (+87 dBm to +93 dBm),
In addition, the interference wave arrival level for the radar base station RBS not to receive interference from the wireless LAN system is -130 dBm, and the wireless communication terminal device T of the wireless LAN system is also used.
If the transmission power of U is 2.5 mW (+4 dBm) / carrier, the transmission line loss for not interfering with the radar base station RBS is +4 dBm-(-130 dBm) = 134 dB. Therefore, the reception level of the radar pulse signal in the wireless communication terminal unit TU of the wireless LAN system under the condition that the transmission path loss exists is 87 dBm-134 dBm = -47 dBm.

Here, if the transmission path loss of the transmission path from the wireless communication terminal unit TU to the radar base station RBS is equal to the transmission path loss of the transmission path from the radar base station RBS to the wireless communication terminal unit TU, The reception level of the radar pulse signal in the wireless communication terminal unit TU is -47 dB above.
When m, the reception level at the radar base station RBS of the radio signal transmitted from the radio communication terminal unit TU is also -4.
It becomes 7 dBm. That is, in the wireless communication terminal unit TU, the reception level of the radar pulse signal is -47 dBm.
When it is less than, the reception level of the radio transmission signal of the radio communication terminal unit TU in the radar base station RBS is also -47.
Even if the wireless communication terminal unit TU transmits a wireless carrier signal with a transmission power of 2.5 mW (+4 dBm) in this state, the received signal level at the radar base station RBS becomes -130 dBm or less. No interference to the radar system RSM will occur. Therefore, the above-47 dBm is set to the first carrier detection level CS.
It is sufficient to set L1 and detect the radar pulse signal in accordance with this detection level CSL1.

In an actual device, a margin of several dB is expected, and the first carrier detection level CS
L1 may be set to, for example, -50 dBm.

On the other hand, in the radar system RSM, depending on the bandwidth and the dynamic range of the front end (preamplifier) of the receiving system, a radio signal is transmitted via a radio channel other than the radio channel used for transmitting / receiving the radar wave. Even when the signal comes, there may be interference due to intermodulation. The second carrier detection circuit 33 is for determining whether or not there is a possibility of giving interference due to this cross modulation to the radar system RSM.
The received signal level of the radar pulse signal transmitted from the SM radar base station RBS is compared with a preset second carrier detection level CSL2. And this second
Of the second detection signal CSS during a period in which a reception signal having a level higher than the carrier detection level CSL2 of is detected.
2 is generated and supplied to the access controller 23.

By the way, the second carrier detection level CSL2 is set as follows, for example. That is, although the radio channel frequency is different from the radio channel being used by the radar system RSM, the received power P of the near frequency by the wireless LAN system received by the radar base station RBS.
Is calculated as follows. ΔP = p ₀ (Δ / 4πL) ² · G · Dtr · Lθ · ΔL where p ₀ is the transmission signal level of the wireless LAN system in the radar reception band, L is the distance from the radar base station RBS, and G is the radar. The gain of the antenna, θ is the beam width of the radar antenna, and Dtr is the traffic density (time rate / unit area) of the wireless LAN system RSM.

[0029]

[Equation 1] However, ln () is the natural logarithm. Specific numerical examples are shown below. G = 3000 (= 34.8 dB) θ = (4π / G) ^1/2 Therefore Gθ = (4πG) ^1/2 = 1.94e2 Dtr = 5e-6 However, the installation density of the wireless LAN system is 1e-4 / m
² (that is, the density of one system per 100 m square on average), 1
Average traffic (time rate) per system is 5e-2
(About 1/10 of the maximum throughput of the evenly distributed wireless LAN system).

Then, the received power P becomes P (dBm) = p ₀ (dBm) −64.2 + 10 · log (ln (Lmax / Lmin)). However, log () is the common logarithm. If the transmission output of the wireless LAN system operating on another wireless channel is 10 dBm, that is, p ₀ = 10 dBm, then P = 54.2 + 10 · log (ln (Lmax / Lmin)) (dBm). Here, if the out-of-band allowable input level for preventing cross modulation in the radar front end is -50 dB, Lmax / Lmin is 13.9. If the maximum reach of radar waves due to the roundness of the earth is 100 km,
Lmin is 7.2 km. Free space loss in the 1.2 GHz band is 111.2 dB, and if the minimum output level (peak) of the radar pulse signal is +87 dBm, the antenna gain of the radar is 35 dB, and the receiving antenna gain of the wireless LAN system is 0 dB, The reception level of the radar pulse signal at the distance of Lmin is +10.8 dBm. Of course, the out-of-band allowable input level is the wireless L
This is due to the specifications of the radar system in which the AN system tries to share the radio channel.

+ 10.8d obtained by the above numerical calculation
If Bm is set as the second carrier detection level CSL2, a wireless LAN using a wireless channel close to the wireless channel used by the radar system RSM.
It is possible to avoid radio signals from the system causing interference due to intermodulation at the front end of the radar base station RBS. It is needless to say that an appropriate margin is set based on the setting accuracy of the second carrier detection level CSL2 and the like when actually mounted on the wireless communication device. Specifically, for example, when a margin of 3 dB is expected, the second carrier detection level CSL2 is +7.
It becomes 8 dBm.

On the other hand, the third carrier detection circuit 34 is
The carrier signal is a received carrier signal for detecting a modulated carrier signal transmitted from another wireless communication terminal unit TU in a wireless LAN system for wirelessly transmitting packet data by an MA (carrier sense multiple access) method. Is compared with a preset third carrier detection level CSL3. Then, the third detection signal CSS3 is generated and supplied to the access controller 23 during a period in which a reception carrier signal having a level higher than the third carrier detection level CSL3 is detected.

Here, the third carrier detection level C
SL3 is set as follows. That is, it is assumed that the frequency band used is 1.2 GHz band, the free space loss (distance 40 m) is 60 dBm, and the received power (distance 4).
0 m) is set to -62 dBm. Further, the band width B is set to 2.
If the noise figure F is 5 Mbaud and the noise figure F is 6 dB, the thermal noise is k * T * B * F = -104 dBm. However, k is Boltzmann's constant and T is temperature. From the above conditions, the carrier detection level CSL2 for detecting a radio signal coming from another radio communication terminal unit TU in the radio LAN system does not malfunction due to thermal noise, and other radio communication is performed even if fading occurs. In order to detect the presence of a radio signal from the device as much as possible, it is set to, for example, -84 dBm (thermal noise +20 dBm). By the way, the access controller 23 includes a radar use determination unit 23c and a radar interference determination unit 23c.
d and a wireless access control unit 23e are provided.
The radar use determination unit 23c, based on the first detection signal CSS1 output from the first carrier detection circuit 32,
It is for detecting whether or not the radar system RSM is operating.

In this wireless LAN system,
When the distance between the wireless communication devices is very short, for example, when there are two wireless communication devices of the own system at an interval of 1 m, the free space loss is 34 dB. The level is -30 dBm
Becomes In this case, since it exceeds the set value of the first carrier detection level CSL1 described above, it is erroneously determined as a radar pulse signal.

Therefore, in order to more accurately determine whether or not the radar pulse signal has arrived, the access controller 2
The radar determination unit 23c of No. 3 is configured as shown in FIG.
That is, the first detection signal CSS1 output from the first carrier detection circuit 32 is input to the first selector 44, the second selector 46, and the pulse length determination circuit 42 via the buffer amplifier 41, respectively. The pulse length determination circuit 42 generally has a signal length of the radar pulse signal of 1 to 1
Paying attention to the fact that the packet data length is 50 μsec at the shortest, while the packet data length is as short as 0 μsec.
The detection signal CSS1 of 1 determines whether the packet data is detected or the radar pulse signal is detected, and is composed of, for example, a counter and a determination unit. The counter detects the pulse width T of the first detection signal CSS1. The determination unit compares the pulse width T detected by the counter with the maximum packet data length Tmax and the shortest packet data length Tmin stored in advance in the registers 43a and 43b. Then, a determination signal PSS indicating whether the comparison result satisfies the condition of T <Tmin or T> Tmax is output.

The first selector 44 selects one of the first detection signal CSS1 and the pulse length detection signal output from the pulse length determination circuit 42 according to the select instruction information stored in the register 45. The detection signal thus selectively output is the periodic signal detection circuit 5
Input to 0. The periodic signal detection circuit 50 generally has no periodicity because packet data is transmitted at random, while the periodic signal detection circuit 50 has clear periodicity for a radar pulse signal. Determines whether the packet data is detected or the radar pulse signal is detected. The determination signal ISS indicating the presence / absence of periodicity output from the periodic signal detection circuit 50 is input to the second selector 46. To be done.

In the second selector 46, according to the select instruction information stored in the register 47, the first detection signal C output from the first carrier detection circuit 32 is output.
SS1, the pulse length determination signal PSS output from the pulse length determination circuit 42, and the periodicity determination signal IS output from the periodic signal detection circuit 50 indicating the presence or absence of the periodicity.
One of S and S is selected and supplied to the stage number protection circuit 48.

In the stage number protection circuit 48, the output frequency of the detection signal CSS1 or the determination signal ISS selectively output from the second selector 46 is counted at regular intervals, and this count value is stored in the register 49a. If the number of protections is exceeded, detection information indicating that the radar system RSM has started using the radio channels f1 to f4 is generated. Further, during the radar use detection, detection information indicating that the radar system RSM has stopped using the wireless channels f1 to f4 is generated when the count value is less than the number of forward protection stored in the register 49b. To be done. The detection flag register 51 sets / resets a detection flag indicating the usage state of the radio channels f1 to f4 by the radar system RSM according to the above detection information.

The radar interference determination section 23d is provided with a second detection signal CS output from the second carrier detection circuit 33.
Based on S2, it is determined whether or not there is a possibility of causing interference due to cross modulation on the radar system RSM. Then, the determination result is supplied to the wireless access control unit 23e.

The radio access control section 23e finally determines whether or not the radio channel is used, based on the judgment result by the radar use judgment section 23c and the judgment result by the radar interference judgment section 23d. Then, in a state where it is determined that the wireless channel can be used without causing interference of the same wireless channel and cross modulation by different wireless channels to the radar system RSM, the CPU 11 of the terminal device body 10 requests the transmission of the data packet. When the signal arrives, the wireless channel is accessed according to the CSMA method based on the third detection signal CSS3 output from the third carrier detection circuit 34, and packet data is transmitted and received.

Next, the operation of the apparatus configured as described above will be described. When the wireless LAN system starts its operation, each wireless communication device declares that its own device is a temporary master station after the power is turned on and after a preset time has been set for each device. Signal is sent to another wireless communication device in the system. Further, each wireless communication device monitors the arrival of a declaration signal from another wireless communication device within the time until the declaration signal is transmitted, and the declaration signal from the other device is sent before the own device transmits the declaration signal. When it arrives, the wireless communication device that has transmitted this declaration signal is recognized as a temporary master station, and the instructions of this temporary master station are followed. In other words, the wireless communication device that sends the declaration signal earliest becomes the temporary master station.

Now, the wireless communication unit TU that has become the temporary master station
First, it sequentially searches a plurality of wireless channels available in its system and receives the wireless signals, and thereby determines for each wireless channel whether the radar system RSM is using this wireless channel. .

That is, the radio carrier signal transmitted by each radio channel is received by the antenna 27 and then input to the first carrier detection circuit 32 via the low noise amplifier 29 and the band pass filter 30. In the first carrier detection circuit 32, the reception level of the wireless carrier signal is the first carrier detection value CS set in advance.
It is detected whether it is L1 (-47 dBm) or more, and the detection signal is input to the radar use determination unit 23c of the access controller 23.

Now, suppose that the radar use determination mode is set to the determination mode using only the first detection signal CSS1. Then, the radar use determination unit 23c
At the second selector 46, the first selector signal C
Since the SS1 is set to be selectively output, the stage number protection circuit 48 receives the first detection signal CSS1. In the stage number protection circuit 48, the first detection signal CS
It is determined whether or not the number of occurrences of S1 exceeds the preset number of backward protections within a certain period.

In this state, for example, the radar system R
It is assumed that the SM performs a radar search using the wireless channels f1 to f4. Then, the first carrier detection circuit 32 outputs the first detection signal CSS1 each time the radar pulse signal transmitted from the radar base station RBS is received. Therefore, the first detection signal C
The number of times SS1 is generated exceeds the number of backward protections within a certain period. As a result, the detection information indicating that the radar is in use is output from the stage number protection circuit 48, and the detection flag of the register 51 is set. It

On the other hand, it is assumed that the radar system RSM is performing a radar search using radio channels other than the radio channels f1 to f4. In this case, since the radar pulse signal is not received in the radio channels f1 to f4, the first detection signal CSS1 is not output from the first carrier detection circuit 32. Therefore, in the stage number protection circuit 48 of the radar use determination unit 23c, the number of times the first detection signal CSS1 is generated does not exceed the number of backward protections within a certain period, and therefore the detection flag of the register 51 holds the reset state. .

When the radar system RSM switches the use channel from the radio channels f1 to f4 to another radio channel, the output of the first detection signal CSS1 from the first carrier detection circuit 32 is interrupted. For this reason,
In the stage number protection circuit 48 of the radar use determination unit 23c,
The number of times the detection signal CSS1 is generated falls below the number of forward protections within a certain period, and as a result, the stage number protection circuit 48 outputs detection information indicating that the radar system RSM is not using the radio channels f1 to f4. As a result, the detection flag of the register 51 is reset.

Further, the wireless communication device T which has become the temporary master station.
U determines whether or not each wireless channel is used by the radar system RSM, and when the wireless transmission is performed using the adjacent wireless channel, the radar system RS
It is determined whether M causes interference due to cross modulation.

That is, the radio carrier signal transmitted by each radio channel is received by the antenna 27 and then input to the second carrier detection circuit 33 via the low noise amplifier 29 and the band pass filter 30. In the second carrier detection circuit 33, the reception level of the wireless carrier signal is the second carrier detection value CS set in advance.
It is detected whether or not L2 (+10.8 dBm) or more, and the detection signal is input to the radar interference determination unit 23d of the access controller 23. Radar interference determination unit 23
At d, it is determined whether or not there is a risk of causing interference due to intermodulation on the radar system RSM according to the detection signal CSS2, and the determination result is supplied to the radio access control unit 23e. The radio access control unit 23e detects a radio channel that is not used by the radar system RSM and, even if radio transmission is performed by another radio channel adjacent to this radio channel, the radio system RS
When it is determined that there is no risk of causing M to cause interference due to intermodulation, the wireless channel is instructed to each wireless communication device in the system as a used channel.

Now, in this state, it is assumed that the operator inputs a packet data transmission instruction in the terminal device body 10. Then, the CPU 11 of the terminal device body 10
First, the radar use determination unit 23 of the access controller 23
The state of the detection flag 51 in c is determined. And
When it is confirmed that the detection flag 51 is in the reset state, that is, the radar system RSM is not using the wireless channels f1 to f4, the bus interface 21 is set in the buffer memory 22 of the wireless LAN adapter 20. The transmission packet data is written via this, and the access controller 23 is instructed to transmit packet data.

In response to this instruction, the access controller 2
First, in the wireless access control unit 23d, based on the detection signal CSS2 of the second carrier detection circuit 33, another wireless communication terminal device TU of the wireless LAN system uses the wireless channels f1 to f4 to send packet data 3 It is determined whether or not transmission is being performed. If it is determined by this determination that no wireless communication terminal unit TU is transmitting, then the transmission control unit 23a transmits the transmission packet data TD and the transmission clock TCK to the modulation circuit 24, and the carrier switch signal CSW. Is sent. Therefore, the modulation circuit 24 becomes ready to output the carrier wave signal, and thereafter starts transmitting four modulated carrier wave signals modulated by the transmission packet data TD. In the wireless access control unit 23d, the wireless channel f1
If it is determined that ~ f4 is already used by another wireless communication terminal device TU, the wireless access control unit 23
No transmission permission is given from the d to the transmission control unit 23a, and as a result, the transmission packet data is not transmitted.

On the other hand, the radar use determining section 23c
When the detection flag 51 is set, that is, the radar system RSM indicates that the radio channels f1 to f4 are being used, the radio access control unit 23d does not use the radar system RSM. Other radio channels are searched. When another wireless channel is found, control is performed to change (handoff) the wireless channel to be used to this wireless channel. This handoff control is performed by, for example, wireless LAN
An arbitrary wireless communication terminal unit TU in the system temporarily becomes a temporary master station, and this temporary master station sends a handoff command to another wireless communication terminal unit TU in the system.

On the other hand, it is assumed that the radar system RSM switches the wireless channel to the wireless channels f1 to f4 used by the wireless LAN system while the wireless communication terminal unit TU is transmitting packet data. Then,
In this case, according to the reception of the radar pulse signal transmitted from the radar base station RBS, the first carrier detection circuit 3
2 outputs the first detection signal CS1. Then, when the cumulative value of the number of times of generation of the first detection signal CSS1 exceeds the number of backward protection within a certain period, the detection flag register 51 of the radar use determination unit 23c changes to the set state at that time. That is, the detection flag is the radar system RS.
The state of M indicates that the wireless channels f1 to f4 are in use. The change in the detection flag 51 is detected by the wireless access control unit 23d, and accordingly, the transmission control unit 23a immediately stops the transmission of the packet data.
Therefore, the interference of the radar system RSM by the wireless LAN system is prevented. Note that the wireless communication terminal unit TU may perform the handoff control described above after this transmission is stopped.

By the way, during the period when the radio communication terminal unit TU is transmitting packet data, the radio carrier signal cannot be detected for some reason and other radio communication terminals arranged relatively close to each other. It is assumed that the device TU starts transmitting packet data. In this case, the wireless communication terminal unit TU that is transmitting the packet data has -57 dB.
Since the wireless carrier wave signal of m or more is received, the first carrier detection circuit 32 outputs the first detection signal CSS1. That is, the detection signal indicating that the radar pulse signal has been detected is generated although the wireless carrier wave signal of the transmission packet data is received instead of the radar pulse signal. Therefore, the radar use determination unit 23c determines that the use of the radio channels f1 to f4 has been started by the radar system RSM, and accordingly, the transmission control unit 23a stops transmitting the packet data. That is, although it is not necessary to stop the transmission of the packet data, the transmission will be stopped.

In order to avoid such a situation, the terminal device main body 10 rewrites the select instruction information in the register 47 of the radar use determining section 23c, so that the second selector 46 outputs the pulse length determining circuit 42. The selected pulse length determination signal PSS is selected.
Then, the pulse length determination circuit 4 is included in the stage number protection circuit 48.
The determination signal PSS output from the signal No. 2 is supplied, whereby the stage number protection circuit 48 changes the state of the detection flag 51 based on the number of times the determination signal PSS is generated. Here, the pulse length determination circuit 42 determines that the pulse width of the first detection signal CSS1 is the shortest packet data length (5
The determination signal PSS is output only when it is shorter than 0 μsec or longer than the longest packet data length. Therefore, even if the first detection signal CSS1 is generated from the first carrier detection circuit 32, if the pulse width thereof corresponds to the packet data length, the determination signal PSS is not output and the radar pulse signal (pulse When the pulse signal length is shorter than the shortest packet data length (1 to 10 μsec), the determination signal PSS is output. Therefore, in the stage number protection circuit 48, the radar system RSM operates the radio channels f1 to f1 according to the number of times the pulse length determination signal PSS is generated.
The detection flag 51 indicating whether or not f4 is being used is controlled. Therefore, it is possible to avoid a situation in which packet data having a high reception level is erroneously recognized as a radar pulse signal and transmission of the packet data is stopped.

On the other hand, in the above description, the carrier detection level CSL1 set in the first carrier detection circuit 32 is set to -5.
Although it is set to 7 dBm, if such a high detection level is obtained, the wireless LAN system will certainly change from the radar system RS.
Although interference with M is prevented, interference from the radar system RSM with the wireless LAN system is not prevented. That is, even if the reception level of the radar pulse signal is less than -57 dm, there is a sufficient possibility that the reception level will interfere with the reception packet data depending on the reception level. In order to reduce this problem, the first carrier detection level CS
L1 may be set to a smaller value, for example, about thermal noise +10 dBm (−94 dBm). However, in this case, not only the radar pulse signal but also the wireless signal coming from the other adjacent wireless LAN system will be detected, and the radar pulse signal is discriminated from the wireless signal from the other wireless LAN system. Need to be detected.

As the detecting means, it is effective to use the above-mentioned pulse length judging circuit 42. However, if the signal length of the radar pulse signal and the shortest packet data length are substantially the same or there is a difference but not a large difference, it becomes difficult for the pulse length determination circuit 42 to make an accurate determination.

Therefore, in order to deal with such a case, it is effective to use the periodic signal detecting circuit 50 provided in the radar use determining section 23c. In other words, the terminal device body 10 rewrites the select instruction information in the register 47 of the radar use determining unit 23c, so that the second selector 46 is set to select the determination signal ISS output from the periodic signal detection circuit 50. To do. Then, the determination signal ISS output from the periodic signal detection circuit 50 is supplied to the stage number protection circuit 48, and the stage number protection circuit 48 changes the state of the detection flag 51 based on the determination signal ISS of the periodic signal. I will let you. Here, as described above, in general, packet data is transmitted randomly, and thus has no periodicity, whereas radar pulse signals have clear periodicity. Then, paying attention to this point, the periodic signal detection circuit 50 determines whether the first detection signal CSS1 or the determination signal PSS of the pulse length determination circuit 42 detects packet data or a radar pulse signal. Is being determined. Therefore, even if the first detection signal CSS1 is generated from the first carrier detection circuit 32, the pulse length determination circuit 4
Even if the determination signal PSS is generated from 2, if the detection signal CSS1 or the determination signal PSS is not a signal having a periodicity, the periodic signal detection circuit 50 does not generate the determination signal ISS. Therefore, in the stage number protection circuit 48, the radar system RSM sets the radio channel f1 to the radio channel f1 in accordance with the number of times of generation of the determination signal ISS output from the periodic signal detection circuit 50, that is, the determination signal that more clearly indicates that it is a radar pulse signal. The detection flag 51 indicating whether or not f4 is being used is controlled. For this reason,
The problem of erroneously determining packet data of another wireless LAN system having a reception level and a signal length that are substantially equal to the radar pulse signal as a radar pulse signal is reduced, which enables stable packet data transmission.

As described above, in the present embodiment, the third carrier detection circuit 3 necessary for the wireless communication terminal unit TU to perform wireless packet transmission according to the CSMA method.
In addition to 4, the first carrier detection circuit 32 and the radar use determination unit 23c are provided, and the first carrier detection circuit 32
Detects a radio carrier signal having a reception level higher than the carrier detection level CSL1 and detects the detection signal CS.
Based on S1, the radar use determination unit 23c determines whether the radar system RSM is using a wireless channel. When the radar system RSM determines that the wireless channel is in use, the packet data is not transmitted through this wireless channel.

In the radio communication unit TU of this embodiment, the second carrier detection circuit 33 and the radar interference judgment section 23 are also provided.
Whether or not there is a possibility of giving cross modulation to the radar system RSM by these circuits even if the own system transmits a radio signal using a radio channel other than the radio channel being used. The use of all radio channels is prohibited when there is a possibility that cross modulation will be given. Therefore, the radar system R
It is possible to surely prevent the trouble of giving interference interference due to cross modulation to the SM.

Therefore, according to the present embodiment, although the packet data is wirelessly transmitted using the same radio channel within the radio area of the existing laser system, the laser system RSM is adversely affected, such as interference. It is possible to operate the wireless LAN system without the need. That is, the wireless LAN system can be operated even in a frequency band such as a quasi-microwave band in which there is no frequency that can be assigned to a new wireless communication system.

Further, in this embodiment, the radar system RSM is used.
As a means for determining whether or not the wireless channel is used by the pulse length determining circuit 42, a pulse length determining circuit 42 is provided in addition to the first carrier detecting circuit 32 for determining the reception level. Based on this, it is possible to determine whether or not the radar system RSM is using a wireless channel. Therefore, the problem of erroneously recognizing the received packet data having a high reception level as a radar pulse signal is reduced, and the situation of unnecessarily stopping the packet data transmission is avoided.

Further, in this embodiment, the radar system RS
As a means for determining whether or not the wireless channel is used by M, a periodic signal detection circuit 50 is newly provided, and the detection signal CSS1 of the first carrier detection circuit 32 for determining the reception level or the pulse length determination circuit 42 Judgment signal PS
S is input to the periodic signal detection circuit 50 to determine the presence / absence of its periodicity, and based on this determination signal ISS, the presence / absence of use of a wireless channel by the radar system RSM can be determined. Therefore, for example, when the detection level CSL1 of the first carrier detection circuit 32 is set low, or when there is no clear difference between the signal length of the radar pulse signal and the shortest packet data length, Even when it is difficult to determine the laser pulse signal based on the pulse length, it is possible to accurately determine whether the radar system RSM uses the wireless channel.

The present invention is not limited to the above embodiment. For example, in the above embodiment, as a mode for determining whether or not the wireless channel is used by the radar system RSM, a. A mode in which the determination is made based only on the reception level detection signal CSS1. b. A mode in which determination is performed based on the reception level detection signal CSS1 and the pulse length determination signal PSS. c. The reception level detection signal CSS1 or the pulse length determination signal PSS and the determination signal IS indicating the presence or absence of its periodicity
A mode that determines based on S and. The case of using is described. However, as the other modes, d. A mode in which only the pulse length determination signal PSS is used for determination. e. A mode in which only the judgment signal ISS indicating the presence or absence of periodicity is used for judgment. May be used.

Further, the above-described determination method for selectively using each mode may be applied to determine whether or not there is a possibility of causing interference due to intermodulation in the radar system. In addition, the determination result is sent to the wireless communication device, for example, as L
You may comprise so that it may display using ED or LCD.

Further, in the above embodiment, the radar system R
The case where the wireless LAN system is configured to be shared by sharing the SM wireless channel has been described as an example. However, in addition to the cellular car / cell phone system, the selective call communication system, the MCA system, the indoor mobile wireless communication system, etc. The channels may be shared to construct a wireless LAN system.

In addition, the type and configuration of the second wireless system, the type and configuration of the wireless communication device, the configurations of the first and second determination means, the configuration and control procedure of the wireless channel use control means, and transmission of transmission packet data. The procedure and the like can be modified in various ways without departing from the scope of the invention.

[0068]

As described above in detail, the wireless communication device of the present invention comprises the first judging means and the second judging means for knowing the state of the wireless channel, and the first judging means
The wireless signal transmitted through the wireless channel is received, and the usage state of the wireless channel by the existing first wireless system is determined based on the reception result.
Even when the wireless signal transmitted via the wireless channel is received by the determining means and the wireless signal is transmitted using the wireless channel other than the wireless channel based on the reception result, It is determined whether or not there is a possibility of giving cross modulation to the wireless system. Then, when the radio channel use control means determines that the radio channel is in a state in which it can be considered to be in use by the first determination means, the use of the radio channel is avoided, and the second determination means. By this, when it is determined that cross modulation may be given to the first wireless system, processing for avoiding use of all wireless channels is executed.

Therefore, according to the present invention, it is possible to perform wireless communication within the wireless area of the existing wireless system without adverse effects such as interference and cross modulation.
As a result, it is possible to provide a wireless communication device that can realize a new wireless communication system by using a desired frequency band.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a wireless communication terminal device of the system shown in FIG.

FIG. 3 is a circuit block diagram showing a configuration of a radar use determination unit of the wireless communication terminal device shown in FIG.

[Explanation of symbols]

RSM ... Radar system RBS ... Radar base station LSM1 to LSM3 ... Wireless LAN system TU11 to TU34 ... Wireless communication terminal device 10 ... Terminal device body 11 ... CPU 12 ... Memory 20 ... Wireless LAN
Adapter 21 ... Bus interface section 22 ... Buffer memory 23 ... Access controller 23a ... Transmission control section 23b ... Reception control section 23c ... Radar use determination section 23d ... Radar interference determination section 23e ... Radio access control section 24 ... Modulation circuit (MOD) 25 ... Transmitter power amplifier 26 ... Circulator 27 ... Antenna 28 ... High frequency switch 29 ... Low noise amplifier 30 ... Band pass filter 31 ... Demodulation circuit 32 ... First carrier detection circuit 33 ... Second carrier detection circuit 34 ... Third Carrier detection circuit 41 ... Buffer amplifier 42 ... Pulse length determination circuit 43a, 43b ...
Register 44 ... First selector 45, 47 ... Select instruction register 46 ... Second selector 48 ... Stage number protection circuit 49a, 49b ... Protection number register 50 ... Period signal detection circuit 51 ... Detection flag register (detection flag)

Claims (5)

[Claims] 1. A wireless communication device used in a second wireless system that performs wireless communication by sharing a wireless channel with a first wireless system that selectively uses a specific wireless channel from a plurality of wireless channels. In receiving a wireless signal transmitted through a selected wireless channel among the plurality of wireless channels, and determining a use state of the wireless channel by the first wireless system based on the reception result. A first determination means and a case where a wireless signal transmitted via the selected wireless channel is received and a wireless signal is transmitted using a wireless channel other than the wireless channel based on the reception result. Even if there is, there is a second judging means for judging whether or not there is a possibility of giving cross modulation to the first wireless system, and the selection is made by the first judging means. When the determined wireless channel is determined to be in use by the first wireless system, the use of the wireless channel is avoided, and the second determination means determines the first wireless channel.
Wireless channel use control means for executing processing for avoiding use of all the wireless channels when it is determined that cross-modulation may be given to the wireless system. Communication device. 2. The first judging means compares the signal level of the radio signal transmitted via the selected radio channel with a predetermined first threshold level, and the transmitted radio signal. Detection means for detecting at least one of the signal length of the signal and the periodicity of the signal, the comparison result of the signal level by the comparison means, and the detection result of the signal length or the periodicity of the signal by the detection means are selectively. The wireless communication device according to claim 1, further comprising means for determining whether or not the wireless channel is used by the first wireless system. 3. The first determination means has, as a first threshold level, a predetermined margin with respect to a minimum reception sensitivity level of a wireless signal transmitted by the device itself, which is assumed in the first wireless system. The wireless communication device of claim 2, having a threshold level set to be received. 4. The second determining means sets the signal level of the wireless signal transmitted via the selected wireless channel to a predetermined second threshold level different from the first threshold level. Comparing means for comparing, detecting means for detecting at least one of the signal length and signal periodicity of the transmitted wireless signal, comparison result of signal levels by the comparing means, and signal length or signal by the detecting means And a means for determining whether or not there is a possibility that cross modulation will be given to the first wireless system, by selectively using the detection result of the periodicity of 1. The wireless communication device according to. 5. The second determination means sets, as the second threshold level, a minimum reception signal level at which it is assumed that a radio signal transmitted by the device itself will undergo intermodulation in the first radio system. The wireless communication device according to claim 4, wherein the wireless communication device has a threshold level set to be received with a predetermined margin.