KR20070017899A - Radar detection apparatus and method thereof - Google Patents

Abstract

The wireless network device includes a signal receiving module and a signal processing module for receiving a radio frequency (RF) signal, the signal processing module including an automatic gain control (AGC) module, the gain of the AGC module being directed to the RF signal. Generate control signals when changed on the basis. The network device selectively controls N time intervals between one of adjacent control signals and non-adjacent control signals and selectively determines that the RF signal is a radar signal when the N time intervals are substantially equal. Module, wherein N is an integer greater than one.

Radar detection, network devices, RF signals, AGC modules, control signals

Description

Radar detection device and its method {RADAR DETECTION APPARATUS AND METHOD THEREOF}

1 illustrates radar carrier modulation and radar parameters according to the prior art.

2 shows different types of radar signals.

3A is a functional block diagram of an exemplary radar detection system in a wireless network device in accordance with the present invention.

3B is a functional block diagram of an exemplary radar detection system in a wireless access point in accordance with the present invention.

3C is a functional block diagram of an exemplary radar detection system in a wireless client station in accordance with the present invention.

3D is a functional block diagram of an example infrastructure network.

3E is a functional block diagram of an ad hoc network.

4A is a graph of AGC gain as a function of time, illustrating the drop in AGC gain when the baseband processor receives a wireless data packet.

4B is a graph of AGC gain as a function of time, illustrating the drop in AGC gain when the baseband processor receives a radar signal.

4C is a graph of AGC gain as a function of time, illustrating the drop in AGC gain when the baseband processor receives a spike-shaped noise pulse.

4D is a graph of AGC gain as a function of time, illustrating the drop in AGC gain when the baseband processor receives a random noise signal.

5 is a flowchart of an exemplary radar detection method in accordance with the present invention.

6A is a functional block diagram of a hard disk drive.

6B is a functional block diagram of a digital versatile disc (DVD).

6C is a functional block diagram of a high definition television.

6D is a functional block diagram of a vehicle control system.

6E is a functional block diagram of a cellular phone.

6F is a functional block diagram of a set top box.

6G is a functional block diagram of a media player.

Related Applications

This application claims the priority of US Provisional Application No. 60 / 706,388, filed August 8, 2005, the entire disclosure of which is incorporated herein by reference.

The present invention relates to radar systems, and more particularly to radar detection algorithms.

Radar is an acronym of Radio Detection and Ranging. The term "radio" refers to the use of radio frequency (RF) waves. The detection and ranging portion of the acronym is made by timing the delay between the transmission of the RF pulse and its subsequent return. If the time delay is Δt, the range can be determined by a simple formula:

R = cΔt / 2

Where c is the luminous flux and c = 3 × 10 ⁸ m / s. In this formula, a factor of 2 represents a return trip.

1 illustrates a common radar carrier modulation or pulse train and other radar parameters. Pulse width PW is the duration of the radar pulse. The reset time RT is the interval between pulses. Pulse repetition time (PRT) is the interval between the start of one pulse and the start of a subsequent pulse. PRT is the sum of PW and RT. That is, PRT = PW + RT. The pulse repetition frequency (PRF) is the number of pulses transmitted per second, which is the inverse of the PRT. Radio frequency (RF) is the frequency of the carrier that is modulated to form a pulse train.

Military organizations use radar communication systems. Until recently, military radar communication systems had almost no interference communication. Recently, however, wireless network communications have increased dramatically. As a result, wireless network signals interfere with military radar communications. Interference between publicly available wireless networks and military radar systems is undesirable for security reasons.

Based on the disclosure by the military organization, the IEEE has defined the IEEE 802.11h specification, which is incorporated herein by reference. IEEE 802.11h attempts to limit wireless networks and wireless network devices from interfering with radar systems. To avoid interference with military radar, support for IEEE 802.11h is required at all access points and client stations that conform to IEEE 802.11a. IEEE 802.11h reduces radio interference by using two techniques: dynamic frequency selection (DFS) and transmit power control (TPC).

If a device using DFS detects other devices on the same wireless channel, the device is switched to another channel as needed. Typically, the AP sends beacons to inform client stations that the AP uses DFS. If the client stations detect radar on the channel, the client stations notify the AP. Based on this information, the AP uses DFS to select the best channel for wireless communications that will not interfere with the radar.

TPC reduces interference by limiting the transmit power of network devices to the minimum level needed to reach the furthest client station. The maximum power limit can be set in the AP and enforced on the client stations associated with that AP. By limiting the transmit power of the client stations, the TPC can limit interference with the radar.

Once the wireless network device detects the radar, the network should stop using that channel within a predetermined time, such as 10 seconds. Communication on that channel may be blocked for subsequent time periods, such as 30 minutes. Some network devices may falsely detect radar on a channel. For example, a network device may incorrectly conclude that noise, such as a signal generated by a microwave instrument or other device, is a radar signal. Despite the fact that the detected signal is not a radar signal, the network will unnecessarily block the channel. As false detections increase, additional channels will be blocked, so fewer channels will be available for network communication. This can significantly degrade network performance.

A wireless network device of the present invention includes a signal receiving module for receiving a radio frequency (RF) signal; A signal processing module comprising an automatic gain control (AGC) module, the control module generating control signals when the gain of the AGC module is changed based on the RF signal; And a control module for selectively measuring N time intervals between one of adjacent control signals and non-adjacent control signals, and selectively determining that the RF signal is a radar signal when the N time intervals are substantially equal. And N is an integer greater than one.

In another aspect, the BBP has a magnitude in which the gain of the AGC module is changed from a first size to a predetermined value and a second size less than the first size, and within a predetermined period, the size greater than the predetermined value from the second size. When changed to, generates one of the control signals. The BBP selectively generates one of the control signals when the gain of the AGC module is changed M times within the predetermined period, where M is an integer greater than one.

In another feature, when the Nth time interval is not substantially equal to the (N + 1) th time interval, the control module determines that the RF signal is not a radar signal. The N time intervals differ by some amount less than 5% of the period of the radar signal. The radar signal has a predetermined pulse width and a predetermined pulse repetition frequency. The RF signal is received on a channel and the control module generates a radar detection signal when the radar signal is detected on the channel. The control module selectively transmits the radar detection signal to other network devices when the radar signal is detected on the channel.

In another aspect, the client station includes a network device, the client station operating in one of an infrastructure mode and an ad hoc mode. The access point includes the network device. The network device includes a media access control (MAC) module, wherein the control module is optionally implemented by a MAC module. The signal receiving module includes one of an RF receiver and an RF transceiver, and the signal processing module includes a baseband processor.

A computer program executed by the processor receives an RF signal; Generating control signals when a gain of an automatic gain control (AGC) module is changed based on the RF signal; And selectively measuring N time intervals between one of adjacent control signals and non-adjacent control signals, and selectively determining that the RF signal is a radar signal when the N time intervals are substantially equal, N is an integer greater than one.

In another aspect, the computer program changes the gain of the AGC module from a first size to a predetermined value and to a second size less than the first size, and within a predetermined period, from the second size to more than the predetermined value. Generating one of the control signals when changed to a large magnitude.

In another aspect, the computer program further comprises selectively generating one of the control signals when the gain of the AGC module is changed M times within the predetermined period, wherein M is greater than one. Is an integer. The computer program further includes determining that the RF signal is not a radar signal when the Nth time interval is not substantially equal to the (N + 1) th time interval. The N time intervals differ by some amount less than 5% of the period of the radar signal. The radar signal has a predetermined pulse width and a predetermined pulse repetition frequency. The computer program further includes receiving an RF signal on a channel and generating a radar detection signal when the radar signal is detected on the channel. The computer program further includes selectively transmitting the radar detection signal to a network device when the radar signal is detected on the channel. The computer program further includes executing the computer program at a client station operating in one of an infrastructure mode and an ad hoc mode. The computer program further includes executing the computer program at the access point. The computer program further includes executing the computer program in a media access control (MAC) module.

In yet another aspect, the systems and methods described above are implemented by a computer program executed by one or more processors. The computer program may reside on computer readable media, such as, but not limited to, memory, nonvolatile data storage, and / or other suitable tangible media.

Other areas in which the present invention may be applied will become apparent from the detailed description provided below. It is to be understood that the detailed description and specific examples representing the preferred embodiments of the present invention are by way of illustration only and are not intended to limit the scope of the present invention.

The invention will be more fully understood from the detailed description and the accompanying drawings.

The following description of the preferred embodiment (s) is merely illustrative and is not intended to limit the invention, its application or use. For clarity, like reference numerals in the drawings indicate like elements. As used herein, the term module, circuit and / or device is an application specific integrated circuit (ASIC), an electronic circuit that executes one or more software or firmware programs, combined logic circuits and / or other suitable components that provide the desired functionality. , Represents a processor and memory (shared, dedicated, or grouped). As used herein, the phrase at least one of A, B and C should be interpreted to mean logic (A or B or C) using non-exclusive logic. As will be appreciated, the steps of the method may be executed in a different order without changing the principles of the present invention.

Referring to FIG. 2, exemplary types of radar signals are shown. Type 1 radar signals include a burst of 18 pulses with a PW of 1 Hz and an RT of 700 Hz. The type 2 radar signal includes a burst of 10 pulses with a PW of 1 Hz and an RT of 330 Hz. The type 3 radar signal includes a burst of 70 pulses with a PW of 2 Hz and an RT of 3 ms. Regardless of the type of radar signal, radar pulses occur in a constant sequence. Spurious noise, such as spikes in electromagnetic radiation generated by microwave instruments and other devices, prevents the detection of radar pulses. However, this noise is random. Thus, despite the random noise, radar sequences can be detected.

3A shows a system 50 for detecting radar. System 50 may include a wireless network device. Radio frequency (RF) transceiver 52 receives RF signals and communicates with baseband processor (BBP) 54. BBP 54 filters, demodulates, and digitizes the RF signals. BBP 54 includes an automatic gain control (AGC) module 56. The gain of the AGC module varies based on the characteristics of the received signal. If the AGC gain falls below the threshold, BBP 54 generates an interrupt signal.

The control module 58 analyzes the interrupts received from the BBP 54 to determine whether the received signal is a radar signal. The control module 58 may be integrated with and / or executed by a media access control (MAC) module. The control module 58 uses a pulse counter 60 that counts interrupts and a time stamp register 62 that records the time of each interrupt. If a predetermined number of adjacent interrupts and / or non-adjacent interrupts occur at substantially the same time interval, control module 58 identifies the signal as a radar signal.

The RF transceiver 52 receives signals, radar signals, and / or noise signals that may include a packet of wireless network data. When the signal is received, the gain of the automatic gain control (AGC) module 56 is changed from a normal value to a lower value. However, after some time period, the gain returns to its normal value. The amount by which the gain is changed and the time the gain returns to its normal value depend on the characteristics of the signal.

3B-3E illustrate various example implementations. In FIG. 3B, an exemplary radar detection system is presented at a wireless access point 63. In FIG. 3C, an exemplary radar detection system is presented at a wireless client station 64. In FIG. 3D, an infrastructure network with wireless client stations 64-1, 64-2,..., And 64-X communicating with an access point 63 is shown. The access point 63 can communicate with the router 65. Modem 66 may provide access to a dedicated communications system (DCS) 67, such as the Internet, wide area network (WAN), and / or local area network (LAN). In FIG. 3E, client stations 64-1, 64-2, ..., and 64-X are configured in ad hoc mode.

Referring to FIG. 4A, if the received signal is a wireless network data packet of at least 100 ms wide, the gain drops to zero and returns to normal after at least 200 ms. On the other hand, if the received signal is a 2 kW wide radar pulse (eg, radar type 3 of FIG. 2), as shown in FIG. 4B, the gain drops to 0 and then returns to a normal value at most 4 kW after. Thus, it is possible to predict the response of the gain to the radio network data packet and / or radar signal.

However, the gain responds differently to the noise signals than the radio network data packet and / or radar signal. For example, if the received signal is a spike-shaped noise pulse, as shown in FIG. 4C, the gain only slightly drops depending on the amplitude and width of the noise and then quickly returns to its normal value. On the other hand, when the received signal is a random noise pulse, as shown in Fig. 4D, the gain drops to zero, but returns to a normal value at 4 dB or more and less than 200 Hz.

Thus, BBP 54 may be programmed to generate an interrupt only if the AGC gain falls below a predetermined threshold X and the gain returns to its normal value within a predetermined time. The predetermined time may be twice the pulse width of the widest radar pulse (eg 4 ms for detecting all radar types in FIG. 2). Specifically, the BBP 54 may be programmed to not generate an interrupt for the situations shown in FIGS. 4C and 4D. With this optional interrupt generation technique, false radar detection can be avoided. In addition, this technology conserves resources such as processing power, memory, and power of the wireless network device.

When the control module 58 receives the interrupt, the pulse counter 60 is triggered to count the interrupt. Each interrupt represents a pulse that is received by the system 50 and can be a radar pulse. The time stamp register 62 records the time stamp for each interrupt. To determine whether the received signal is actually a radar signal, the control module 58 compares the time difference between a predetermined number of consecutive time stamps. If the time stamps occur at substantially the same time intervals, the control module 58 concludes that the received signal is a radar signal.

Specifically, the control module 58 calculates the time difference between a predetermined number of consecutive time stamps. For example, if interrupt 1 is detected at time t ₁ , interrupt 2 is detected at time t ₂ , interrupt 3 is detected at time t ₃ , and so on, the control module 58 may execute the time difference ( t ₂ -t ₁ ), (t ₃ -t ₂ ), etc. The control module 58 then determines whether the time differences are substantially the same. If the time differences are substantially the same, the control module 58 concludes that the detected signal is a radar signal.

In use, if a stream of radar pulses is received by the RF transceiver 52, the AGC gain falls similar to the drop shown in FIG. 4B for each pulse. BBP 54 generates an interrupt for each pulse. Upon receiving each interrupt, control module 58 triggers pulse counter 60. The pulse counter 60 counts each interrupt. The time stamp register 62 records the time stamp for each interrupt. The control module 58 calculates the time difference between the N consecutive time stamps, and then generates (N-1) time difference values. If the (N-1) time differences are substantially the same within a predetermined tolerance, the control module 58 concludes that the received signal is a radar signal.

Further optimization can be used for faster convergence and faster determination of false signals. The control module 58 calculates the time difference between the incoming pulse and the pulse immediately preceding the pulse, and then compares this time difference with the previous time difference. Specifically, the control module 58 compares whether (t _i -t _i-1 ) and (t _i-1 -t _i-2 ) are within a predetermined tolerance of each other. If within tolerance, control module 58 continues with further checking. If not within the tolerance, the control module 58 resets the pulse counter 60 and then starts checking again. If the received signal is a noise signal, the control module 58 determines that the received signal is not a radar signal, without waiting to obtain N signals.

Clearly, radar pulses occur at regular time intervals, but noise pulses generally occur randomly. As a result, the time difference between the radar pulses is substantially the same, but the time difference between the noise pulses is not the same. Thus, simply calculating and comparing the time differences between approximately five pulses is sufficient to determine whether the received signal is a radar signal.

)가 각 시간차에 부가된다. 이에 따라, 시간차들 (t₂-t₁),(t₃-t₂) 등은

만큼 다를 수 있다. 일반적으로,

는 레이더 신호의 주기의 5% 미만이 될 수 있다. 예를 들어, 타입 1 및 타입 2 레이더에 대해,

는 15㎲가 될 수 있고, 타입 3 레이더에 대해,

는 30㎲가 될 수 있다. Even if the radar pulses have a finite frequency, the time difference between successive pulses may not be exactly the same. This is because the RT between radar pulses may not always be constant. In addition, signal processing times such as interrupt generation, pulse counting, etc. cause an aggregate time delay, which should be taken into account when comparing time differences. Therefore, narrow tolerance in time difference (

) Is added to each time difference. Accordingly, the time differences t ₂ -t ₁ , t ₃ -t ₂ , etc.

Can be as different. Generally,

May be less than 5% of the period of the radar signal. For example, for type 1 and type 2 radars,

Can be 15㎲, for Type 3 radar,

May be 30 ms.

When a client station detects a radar, the station informs other client stations (in ad hoc mode) or the associated AP (in infrastructure mode). In infrastructure mode, the AP broadcasts beacons to inform stations that they will use another channel without radar instead of the current channel. Certain regulations require that the total time of all broadcast transmissions not exceed a predetermined period, such as 200 ms. Therefore, fast and accurate radar detection is important.

Obviously, the system 50 for detecting radar recognizes that detecting a radar signal is sufficient because the channel is not available once any type of radar is detected, regardless of the type of radar. Thus, once the radar is detected, the system 50 does not necessarily need to determine the type of radar. Instead, the system 50 only needs to check whether a predetermined number of consecutive pulses have occurred at substantially the same time intervals, to determine only whether the received signal is a radar signal.

Also, by measuring the time difference between all P pulses instead of consecutive pulses, the radar can be effectively detected, where P is an integer greater than one. In another variation, the BBP 54 may be programmed to generate an interrupt for the control module 58 only after the AGC gain has dropped below the threshold X a predetermined number of times within a predetermined period. This allows the control module 58 to perform other functions and make better use of resources such as processing power for a time that is not interrupted by the BBP 54.

Pulse counter 60 and time stamp register 62 are shown separately for purposes of illustration, which may be implemented within control module 58. In addition, all or part of the system 50 for detecting the radar may be implemented by firmware.

Next, FIG. 5 shows a method 100 for detecting a radar. The method 100 begins at 102. In step 103, the pulse counter 60 is reset (i = 0). In step 104, the BBP 54 determines whether the signal received by the RF transceiver 52 drops the gain of the AGC module 56 below a predetermined threshold X. If the gain does not fall below the threshold X, at step 106 the signal is ignored as noise and the method 100 returns to step 104.

If the gain falls below the threshold X, at step 108, the BBP 54 determines whether the gain has returned to its normal value for less than a maximum of 4 dB. If the gain returns to normal for more than 4 dB, then at step 110, BBP 54 determines whether the gain has returned to normal for more than 200 dB. If the gain returns to a normal value for less than 200 Hz, then at step 106 the signal is ignored as noise and the method 100 returns to step 102. If the gain has returned to normal for more than 200 dB, then at step 112 the signal is considered a normal wireless network data packet and the method 100 returns to step 104.

However, if the gain returns to normal for less than 4 dB in step 108, the signal may be radar or noise. In this case, BBP 54 generates an interrupt at step 114. Control module 58 triggers pulse counter 60 to increment pulse count i at step 116. In step 118, the time stamp register 62 writes a time stamp t _i for the detected pulse.

In step 119, the control module 58 determines whether the time differences t _i -t _i-1 and t _i-1 -t _i-2 are equal within a predetermined tolerance. If the time differences are not equal, then at step 125, the control module 58 determines that the signal is not a radar, and the method 100 returns to step 103. If the time differences are equal, then at step 120, the control module 58 determines whether the pulse count i is less than a predetermined number N, where N is an integer greater than one. If the pulse count i is less than N, the method 100 returns to step 104. If the pulse count (i) is N, then the control module 58 at step 122, (t ₂ -t ₁ ), (t ₃ -t ₂ ), ..., (t _N -t _N-1 ) Measure the time difference between the time stamps of the N consecutive pulses.

) 내에서 거의 같으면, 단계(126)에서, 제어 모듈(58)은 검출된 신호가 레이더 신호임을 결정한다. 시간차들이 같지 않으면, 단계(125)에서, 제어 모듈(58)은 검출된 신호가 레이더 신호가 아님을 결정하 고, 방법(100)은 단계(103)로 돌아간다. 도 2에 나타낸 레이더 신호들에 있어서,

는 타입 1 및 타입 2 레이더 신호들에 대해서는 15㎲이고, 타입 3 레이더 신호에 대해서는 30㎲이다. In step 124, the control module 58 compares the time difference between successive time stamps. For example, the control module 58 compares whether (t ₃ -t ₂ ) is approximately equal to (t ₂ -t ₁ ), and the like. The time differences may have some tolerance (

If approximately equal), then at step 126, control module 58 determines that the detected signal is a radar signal. If the time differences are not equal, at step 125, control module 58 determines that the detected signal is not a radar signal and the method 100 returns to step 103. In the radar signals shown in Figure 2,

Is 15 ms for Type 1 and Type 2 radar signals and 30 ms for Type 3 radar signals.

If the detected signal is confirmed as a radar signal, the client station detecting the radar transmits information on the network that it has detected the radar through the channel. This client station sends information to the associated AP if the network is operating in infrastructure mode, or to other stations in the network if the network is operating in ad hoc mode. Then, in step 128, the AP (in infrastructure mode) broadcasts information about the new channel that can be used for communication to all client stations in the network. The method 100 ends at 130.

The present invention is quite scalable in contrast to conventional attempts that are very specific to certain types of radar pulses. For successful radar determination, the present invention utilizes the periodic and time invariant characteristics of the radar pulses and the random characteristics of the noise signals. Since countries introduce their radar pulse determination requirements, the number of types of radar pulses that a wireless network device needs to determine increases. The scheme of the present invention provides a single integrated method for identifying radar pulses that may be introduced in the future.

6A-6G illustrate various exemplary implementations of the invention. Referring to FIG. 6A, the present invention may be implemented in a hard disk drive 400. The invention may be implemented in either or both of the signal processing and / or control circuits, generally indicated at 402 in FIG. 6A. In some implementations, signal processing and / or control circuitry 402 and / or other circuitry (not shown) in HDD 400 may process data, code and / or encrypt, perform calculations, and / or Or format the data output to and / or received from the magnetic storage medium 406.

The HDD 400 may be a host device (not shown), such as a computer, a personal digital assistant, a mobile phone, a media or MP3 player, or the like, via one or more wired or wireless communication links 408. Communicate with the devices. The HDD 400 may be coupled to read only memory (ROM), low latency nonvolatile memory such as flash memory, memory 409 such as random access memory (RAM), and / or other suitable electronic data storage devices.

Referring to FIG. 6B, the present invention can be implemented in a digital versatile disc (DVD) drive 410. The present invention may be implemented in either or both of the signal processing and / or control circuitry 412 of the DVD drive 410 and the mass data storage device 418. Signal processing and / or control circuitry 412 and / or other circuitry (not shown) within DVD 410 may process data, code and / or encrypt data, perform calculations, and / or magnetic storage media 416. Format the data being read from and / or written to). In some implementations, the signal processing and / or control circuitry 412 and / or other circuitry (not shown) within the DVD 410 may encode and / or decode and / or any other signal processing functions associated with the DVD drive. I can do it.

DVD drive 410 may communicate with an output device (not shown), such as a computer, television, or other device, through one or more wired or wireless communication links 417. The DVD 410 may communicate with a mass data storage device 418 that stores data in a nonvolatile manner. The mass data storage device 418 can include a hard disk drive (HDD). The HDD may have the configuration shown in FIG. 6A. The HDD may be a mini HDD including one or more platters having a diameter smaller than about 1.8 ". The DVD 410 may be a low latency nonvolatile memory such as flash memory, RAM, ROM, or the like. Memory 419 and / or other suitable electronic data storage device.

With reference to FIG. 6C, the present invention can be implemented in a high definition television (HDTV) 420. The present invention may be implemented in either or both of the signal processing and / or control circuitry 422 of the HDTV 420 and the mass data storage device 427. HDTV 420 receives HDTV input signals in either a wired or wireless format and then generates HDTV output signals for display 426. In some implementations, the signal processing circuitry and / or control circuitry 422 and / or other circuitry (not shown) of the HDTV 420 can process data, code and / or encrypt, perform calculations, and Format and / or perform any other type of HDTV processing as required.

HDTV 420 may communicate with mass data storage 427, which stores data in a non-volatile manner, such as optical and / or magnetic storage. At least one HDD may have the configuration shown in FIG. 6A, and / or at least one DVD may have the configuration shown in FIG. 6B. The HDD may be a mini HDD including one or more platters having a diameter less than about 1.8 ". HDTV 420 may include low latency nonvolatile memory such as flash memory, memory 428 such as RAM, ROM, and the like. And / or other suitable electronic data storage device, HDTV 420 may also support connection with a WLAN via WLAN network interface 429.

Referring to FIG. 6D, the present invention may be implemented in the control system of the vehicle 430 and the mass data storage device 446 of the vehicle control system 430. In some implementations, the present invention receives inputs from one or more sensors, such as a temperature sensor, pressure sensor, rotation sensor, airflow sensor and / or any other suitable sensor, and / or engine operating parameters, A powertrain control system 432 may be implemented that generates one or more output control signals, such as transmission operating parameters and / or other control signals.

In addition, the present invention may be implemented in other control system 440 of vehicle 430. Control system 440 may also receive signals from input sensors 442 and / or output control signals to one or more output devices 444. In some implementations, the control system 440 can be an anti-lock brake system (ABS), navigation system, telematics system, vehicle telematics system, lane departure warning system, adaptive cruise control. The system can be part of a car entertainment system such as stereo, DVD, and compact discs. Other implementations are also contemplated.

The powertrain control system 432 can communicate with a mass data storage device 446 that stores data in a nonvolatile manner. Mass data storage 446 may include, for example, optical and / or magnetic storage devices, such as a hard disk drive (HDD) and / or a DVD. At least one HDD may have the configuration shown in FIG. 6A, and / or at least one DVD may have the configuration shown in FIG. 6B. The HDD may be a mini HDD including one or more platters having a diameter smaller than about 1.8 ". The powertrain control system 432 may be a low latency nonvolatile memory such as flash memory, a memory such as RAM, ROM, or the like. 447) and / or other suitable electronic data storage device .. The powertrain control system 432 may also support connection with a WLAN via a WLAN network interface 448. The control system 440 may also be capable of mass communication. It may include a data storage device, a memory and / or a WLAN interface (all of which are not shown).

With reference to FIG. 6E, the present invention may be implemented in a cellular phone 450 that may include a cellular antenna 451. The present invention may be implemented and / or implemented in either or both of the signal processing and / or control circuitry 452 and the mass data storage device 464 of the cellular phone 450. In some implementations, cellular phone 450 may include a microphone 456, audio output 458 such as a speaker and / or audio output jack, display 460, and / or a keypad, pointing device, voice actuation. And / or an input device 462, such as other input device. Signal processing and / or control circuitry 452 and / or other circuitry (not shown) of the cellular phone 450 may process, code and / or encrypt data, perform calculations, format data, and And / or other cellular phone functions.

The cellular phone 450 may include a mass data storage device 464 that stores data in a non-volatile manner, such as, for example, a hard disk drive (HDD) and / or optical and / or magnetic storage devices such as a DVD. Can communicate. At least one HDD may have the configuration shown in FIG. 6A, and / or at least one DVD may have the configuration shown in FIG. 6B. The HDD may be a mini HDD including one or more platters having a diameter smaller than about 1.8 ". Cellular phone 450 may include low latency nonvolatile memory such as flash memory, memory 466 such as RAM, ROM, or the like. And / or other suitable electronic data storage device The cellular phone 450 may also support connection with a WLAN via a WLAN network interface 468.

Referring to FIG. 6F, the present invention may be implemented in the set top box 480. The present invention may be implemented in either or both of the signal processing and / or control circuitry 484 of the set top box 480 and the mass data storage device 490. Set top box 480 receives signals from a source, such as a broadband source, and is standard and / or high definition audio / video suitable for display 488, such as televisions and / or monitors and / or other video and / or audio output devices. Output signals. The signal processing and / or control circuitry 484 and / or other circuitry (not shown) of the set-top box 480 processes the data, performs coding and / or encryption, performs calculations, formats the data, And / or any other set top box function.

The set top box 480 may communicate with a mass data storage device 490 that stores data in a non-volatile manner. Mass data storage device 490 may include optical and / or magnetic storage devices such as, for example, hard disk drives (HDDs) and / or DVDs. At least one HDD may have the configuration shown in FIG. 6A, and / or at least one DVD may have the configuration shown in FIG. 6B. The HDD may be a mini HDD including one or more platters having a diameter smaller than about 1.8 ". The set top box 480 may be a memory 494 such as low latency nonvolatile memory such as flash memory, RAM, ROM, or the like. And / or other suitable electronic data storage device Set-top box 480 may also support connection with a WLAN via a WLAN network interface 496.

Referring to FIG. 6G, the present invention may be implemented in a media player 500. The present invention may be implemented in either or both of the signal processing and / or control circuitry 504 of the media player 500 and the mass data storage device 510. In some implementations, the media player 500 includes a display 507 and / or user input 508 such as a keypad, touchpad, or the like. In some implementations, the media player 500 typically displays menus, drop down menus, icons and / or point and click interfaces via the display 507 and / or user input 508. a graphical user interface (GUI) using the interface. The media player 500 further includes an audio output 509, such as a speaker and / or an audio output jack. Signal processing and / or control circuitry 504 and / or other circuitry (not shown) of the media player 500 may process, code and / or encrypt data, perform calculations, format the data, and And / or any other media player function.

The media player 500 can communicate with a mass data storage device 510 that stores data, such as compressed audio and / or video content, in a nonvolatile manner. In some implementations, compressed audio files include files that follow the MP3 format or other suitable compressed audio and / or video formats. Mass data storage devices may include optical and / or magnetic storage devices such as, for example, hard disk drives (HDDs) and / or DVDs. At least one HDD may have the configuration shown in FIG. 6A, and / or at least one DVD may have the configuration shown in FIG. 6B. The HDD may be a mini HDD including one or more platters having a diameter less than about 1.8 ". The media player 500 may include a low latency nonvolatile memory such as flash memory, memory 514 such as RAM, ROM, or the like. And / or to other suitable electronic data storage device Media Player 500 may also support connection with a WLAN via WLAN network interface 516. Other implementations in addition to those described above may be contemplated. .

From the above description, those skilled in the art will recognize that the teachings of the present invention can be implemented in various forms. Thus, while the invention has been described in connection with specific examples, other modifications will become apparent to those skilled in the art upon examination of the drawings, specification and claims that follow, and the true scope of the invention is not limited to the disclosed form.

As described above, the present invention utilizes the periodic and time-invariant characteristics of the radar pulses and the random characteristics of the noise signals, i.e., using the characteristics that the time difference between radar pulses is substantially the same but the time difference between the noise pulses is not equal By calculating and comparing the time difference between the predetermined number of pulses received, it is possible to reliably determine whether the signal is a radar signal. That is, the present invention provides a single integrated method that can identify radar pulses in response to the increasing types of radar pulses as each country introduces its radar pulse determination requirements.

Claims (18)

A signal receiving module for receiving a radio frequency (RF) signal; A signal processing module comprising an automatic gain control (AGC) module, the control module generating control signals when the gain of the AGC module is changed based on the RF signal; And A control module for selectively measuring N time intervals between one of adjacent control signals and non-adjacent control signals, and selectively determining that the RF signal is a radar signal when the N time intervals are substantially equal; And N is an integer greater than one. The method of claim 1, The signal processing module is configured such that the gain of the AGC module is changed from a first size to a predetermined value and a second size smaller than the first size, and within a predetermined time period, from the second size to a size larger than the predetermined value. When generated, generate one of the control signals. The method of claim 2, The signal processing module selectively generates one of the control signals when the gain of the AGC module is changed by M times within the predetermined period, wherein M is an integer greater than one. . The method of claim 1, And when the Nth time interval is not substantially equal to the (N + 1) th time interval, the control module determines that the RF signal is not a radar signal. The method of claim 1, Wherein said N time intervals differ by a predetermined magnitude less than 5% of the period of a radar signal. The method of claim 1, And the radar signal has a predetermined pulse width and a predetermined pulse repetition frequency. The method of claim 1, The RF signal is received on a channel, and the control module generates a radar detection signal when the radar signal is detected on the channel. The method of claim 7, wherein And the control module selectively transmits the radar detection signal to other network devices when the radar signal is detected on the channel. The method of claim 1, The client station operating in one of an infrastructure mode and an ad hoc mode. An access point comprising the wireless network device of claim 1. Receiving a radio frequency (RF) signal; Generating control signals when a gain of an automatic gain control (AGC) module is changed based on the RF signal; And Selectively measuring N time intervals between one of adjacent control signals and non-adjacent control signals, and selectively determining that the RF signal is a radar signal when the N time intervals are substantially equal, N is an integer greater than 1, the radar detection method. The method of claim 11, The control when the gain of the AGC module is changed from a first size to a predetermined value and a second size smaller than the first size, and within a predetermined period, to change from the second size to a size larger than the predetermined value. Generating one of the signals. The method of claim 12, Selectively generating one of the control signals when the gain of the AGC module is changed by M times within the predetermined time period, wherein M is an integer greater than one. The method of claim 11, And determining that the RF signal is not a radar signal when the Nth time interval is not substantially equal to the (N + 1) th time interval. The method of claim 11, And the N time intervals differ by a predetermined magnitude less than 5% of the period of the radar signal. The method of claim 11, And the radar signal has a predetermined pulse width and a predetermined pulse repetition frequency. The method of claim 11, Receiving the RF signal on a channel; And Generating a radar detection signal when the radar signal is detected on the channel. The method of claim 17, Selectively transmitting the radar detection signal to other network devices when the radar signal is detected on the channel.

Images