KR101360659B1 - Method and apparatus for sensing multi-path spectrum of cognitive radio system and cognitive radio system using these - Google Patents

Abstract

Multipath spectrum detection apparatus for a cognitive radio system according to an embodiment of the present invention is a spectrum detector for detecting at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter, And a processor determining an occupation state of a channel corresponding to the at least one spectrum.

Description

METHOD AND APPARATUS FOR SENSING MULTI-PATH SPECTRUM OF COGNITIVE RADIO SYSTEM AND COGNITIVE RADIO SYSTEM USING THESE}

The present invention relates to an apparatus and method for spectrum detection, and more particularly, to an apparatus and method for multipath spectrum detection for a cognitive radio system.

The present invention is derived from the research conducted as part of the IT original technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunication Research and Development. [Task management number: 2005-S-002-05, Title: Cognitive radio for improving spectrum use efficiency Technology development].

Recently, due to the development of mobile communication technology and the increase of the frequency demand, the exhaustion of the frequency resource is getting serious. Therefore, the technology for the efficient use of such frequency resources has attracted attention. Among them, Cognitive Radio (CR) technology using the TV white-space band is the most applicable technology, and active research and standardization are in progress recently.

A cognitive radio (CR) system allows the use of wireless devices in unlicensed bands, so it is necessary to monitor the availability of frequency bands in real time in order not to interfere with existing users.

Thus, cognitive radio (CR) devices must be able to detect various signals, such as wireless microphones, TV signals, etc. operating in the TV band.

An embodiment of the present invention is to provide a multi-path spectrum detection apparatus and method capable of detecting signals of very low level using a multi-band path and at the same time distinguishing the types of signals.

Another object of the present invention is to provide a multipath spectrum detection apparatus and method capable of excellent spectrum sensing by increasing a signal-to-noise ratio (SNR) for a specific spectrum of a signal being used in a band.

Another object of the present invention is to provide an apparatus and method for multipath spectrum detection capable of maximizing the performance of a sensing algorithm used to recognize a surrounding wireless environment.

Multipath spectrum detection apparatus for a cognitive radio system according to an embodiment of the present invention includes a spectrum detector for detecting at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter; And a processor determining an occupation state of a channel corresponding to the at least one spectrum.

A cognitive radio system according to an embodiment of the present invention is a multi-path spectrum detection device for determining the occupancy state of a channel, a MAC module for allocating at least one available spectrum band based on the occupancy state of the channel, and the allocated And a PHY module for establishing a channel according to at least one spectrum band.

In the multi-path spectrum detection method for a cognitive radio system according to an embodiment of the present invention, detecting at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter, and the Determining an occupation state of a channel corresponding to the at least one spectrum.

According to an embodiment of the present invention, the signal-to-noise ratio (SNR) of a specific spectrum of a signal being used in a band can be increased, and a spectrum sensing result superior to the existing detection level of the spectrum sensing algorithm can be obtained.

1 is a block diagram of a multi-path spectrum detection apparatus for a cognitive radio system according to a first embodiment of the present invention.
2 is a block diagram of a multi-path spectrum detection apparatus for a cognitive radio system according to a second embodiment of the present invention.
3 is a block diagram of a multi-path spectrum detection apparatus for a cognitive radio system according to a third embodiment of the present invention.
4 is a block diagram of a cognitive radio system including a multi-path spectrum detection apparatus according to an embodiment of the present invention.
5 is a flowchart of a multi-path spectrum detection apparatus for a cognitive radio system according to an embodiment of the present invention.

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

1 is a block diagram of a multi-path spectrum detection apparatus for a cognitive radio system according to a first embodiment of the present invention, Figure 2 is a multi-path spectrum detection apparatus for a cognitive radio system according to a second embodiment of the present invention It is a block diagram.

Referring to FIG. 1, an apparatus for detecting a multipath spectrum for a cognitive radio system includes an antenna 110, a spectrum detector 130, and a processor 150.

The antenna 110 receives a radio frequency (RF) input signal and provides it to the spectrum detector 130. Here, the antenna 110 may be a broadband antenna operating in a wide frequency band ranging from several MHz to several hundred GHz.

The spectrum detector 130 includes at least one of a wideband filter and a narrowband filter, and receives the radio frequency (RF) received through the antenna 110 using the wideband filter 131 and the narrowband filter 133. Detect at least one spectrum from the input signal.

Here, the broadband filter 131 may have a band equal to a band usable by the cognitive radio system as the filtering band.

The narrowband filter 133 is designed to filter well-known signals, such as, for example, pilot signals, and may have a predetermined filtering band.

In addition, the narrowband filter 133 may be composed of at least one, that is, one or more narrowband filters, and the center frequency and bandwidth of the narrowband filter may be variably adjusted.

The spectrum detector 130 senses the entire band (broadband) of the signal to be detected by using multiple paths (a wide band and a plurality of narrow bands) and at the same time detects a point where a specific spectrum is expected as a narrow band. The time required for detecting can be reduced.

In addition, the detection of the narrow band can significantly reduce the requirement of the digital filter tab implemented in the sensing algorithm performed by the processor 150.

In addition, the spectrum detector 130 may include a plurality of narrowband filters 233, 235, and 237 as shown in FIG. 2.

The sensing algorithm used in the multipath spectrum detection apparatus according to an embodiment of the present invention mainly uses spectral components of a specific position among signals in a frequency band, so that a narrowband filter corresponding to the specific position may have a plurality of narrowband filters. have.

As such, one or more narrowband filters may be added in addition to the wideband filter to find signals that are not detected through the wideband filter.

The description of the remaining components in FIG. 2 is the same as the description of the components having the same names as in FIG. 1 and the description of the corresponding parts will be referred to.

The spectrum detector 130 passes the radio frequency (RF) input signal received through the antenna 110 through each of the wideband filter 131 and the narrowband filter 133, thereby transmitting the radio frequency (RF) input signal from the radio frequency (RF) input signal. At least one spectrum can be detected.

The processor 150 determines an occupation state of a channel corresponding to at least one spectrum detected by the spectrum detector 130.

Here, the processor 150 may determine the occupancy state of the channel and the type of the channel by a cyclo-stationary algorithm. Cyclo-stationary algorithm is a kind of sensing algorithm used to recognize the surrounding wireless environment.

In the case of using the cyclo-stationary algorithm, the power spectral value for the cyclic frequency of the signal to be detected is calculated, and the optimal statistic is calculated from the calculated power spectral value according to the optimal statistics. The signal can be detected.

In general, the sensing algorithm detects a signal-to-noise ratio (-SNR) signal, so it is very important to reduce the noise floor as much as possible. The narrower the frequency bandwidth, the lower the noise floor.

The multipath spectrum detection apparatus according to an embodiment of the present invention can increase the signal-to-noise ratio of a specific spectrum being used in a band by using a narrowband filter, thereby obtaining a spectrum detection result superior to the existing detection level of a sensing algorithm. have.

3 is a block diagram of a multi-path spectrum detection apparatus for a cognitive radio system according to a third embodiment of the present invention.

Referring to FIG. 3, the spectrum detector 330 of the multipath spectrum detection apparatus 300 for a cognitive radio system includes a variable narrowband filter 333, and the processor 350 includes a control signal generator 355. can do.

Since the description of the antenna 310, the broadband filter 331, and the processor 350 is the same as the description of the corresponding component of FIG. 1, the corresponding part will be referred to.

The variable narrowband filter 333 is a narrowband filter capable of adjusting the center frequency and the bandwidth of the narrowband filter, and the center of the narrowband filter according to the control signal received by the spectrum detector 330 from the processor 350. By adjusting the frequency and bandwidth, it is possible to operate as a variable narrowband filter.

In addition, a variable narrowband filter 333 capable of adjusting the center frequency and the bandwidth according to the spectral characteristics of the signal to be monitored may find a signal not found during wideband sensing.

To this end, the processor 350 may include a control signal generator 355 for generating a control signal to adaptively adjust the center frequency and bandwidth of the narrowband filter (ie, the variable narrowband filter 333). have.

The center frequency and bandwidth of the narrowband filter can be adjusted according to the characteristics of the signal to be monitored by the control signal.

4 is a block diagram of a cognitive radio system including a multi-path spectrum detection apparatus according to an embodiment of the present invention.

Referring to FIG. 4, a cognitive radio system according to an embodiment of the present invention includes a multipath spectrum detection device 410, a MAC module 420, and a PHY module 430.

In addition, the cognitive radio system according to an embodiment of the present invention may further include a data signal processing module 440, a transmission / reception switch 450, and an antenna 460.

The multipath spectrum detection device 410 determines the occupation state of the channel.

In addition, the multi-path spectrum detection device 410, the spectrum detector 415 for detecting at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter, and at least one The processor 417 may determine an occupation state of a channel corresponding to the spectrum.

In addition, since the functions and operations of the multipath spectrum detection apparatus 140 are the same as those of the multipath spectrum detection apparatus 100 of FIG. 1, the description of the corresponding part will be referred to.

The MAC module 420 receives information received from the multipath spectrum detection device 410 (e.g., channel occupancy status, RSSI, frequency type, signal) to allocate an unoccupied or interference-free spectrum available for communication. Type).

MAC module 420, more precisely cognitive engine 425, allocates at least one available spectral band based on the occupied state of the channel.

In addition, the MAC module 420 may set the priority of the channel based on the occupancy state of the channel and allocate at least one spectrum band according to the priority.

The PHY module 430 sets up a channel according to at least one spectrum band allocated by the MAC module 420.

In addition, the PHY module 430 may be operable to reset the data signal processing module 440 including the data transmitter and the data receiver based on at least a portion of the available spectrum. For example, the PHY module 430 may adjust transmission power control for the data transmitter of the data signal processing module 440 or tune a filter for the data receiver such that the data receiver operates within a specific frequency range.

The transmit / receive switch 450 switches to transmit or receive data of the data signal processing module 440 when transmitting or receiving data through the antenna 460.

5 is a flowchart of a multi-path spectrum detection apparatus for a cognitive radio system according to an embodiment of the present invention.

4 and 5, while the data signal processing module 440 of the cognitive radio system of FIG. 4 is operated, a radio frequency (RF) input signal is received by the antenna 413 that senses spectrum (501). ) May be provided to the spectrum detector 415.

The spectrum detector 415 then detects at least one spectrum by passing a radio frequency (RF) input signal through the filter using at least one of a wideband filter and a narrowband filter (503).

In this case, the RF signal may be passed through each of the wideband filter and the at least one narrowband filter to detect at least one spectrum.

Here, the filtering band of the broadband filter may be the same as the band usable by the cognitive radio system.

In addition, the narrowband filter is designed to filter well-known signals, such as, for example, pilot signals, and may have a predetermined filtering band.

In addition, the narrowband filter may be composed of at least one, that is, one or a plurality of narrowband filters, and the center frequency and bandwidth of the narrowband filter may be variably adjusted. Prior to step 503, the processor 417 may include generating a control signal to adaptively adjust the center frequency and bandwidth of the narrowband filter. Accordingly, when detecting at least one spectrum of step 503, the at least one spectrum may be detected by adjusting the center frequency and the bandwidth of the narrowband filter according to the control signal.

In this case, if at least one spectrum is not detected, the spectrum detector 415 passes the received RF input signal back through the filters to continuously perform spectrum detection (505).

If at least one spectrum is detected in operation 505, the processor 417 determines an occupation state of a channel corresponding to the at least one spectrum (507).

The cognitive engine 425 of the MAC module 420 then allocates at least one available spectral band based on the occupied state of the channel received from the multipath spectrum detection device 410.

The multipath spectrum detection method according to an embodiment of the present invention described with reference to FIG. 5 may include steps processed in time series in the multipath spectrum detection apparatus and the cognitive radio system described with reference to FIGS. 1 to 4. .

Therefore, although omitted below, the contents described above with respect to the contents related to the multipath spectrum detection apparatus and the cognitive radio system described with reference to FIGS. 1 to 4 also apply to the multipath spectrum detection method according to an embodiment of the present invention. Apply.

The methods according to the present invention can be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be construed as being limited to the embodiments described, but should be determined by equivalents to the appended claims, as well as the appended claims.

110: antenna
130: spectrum detection unit
131: wideband filter
133: narrowband filter
150: processor

Claims (20)

In the multi-path spectrum detection apparatus for a cognitive radio system,
A spectrum detector for sensing at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter; And
A processor for determining an occupation state of a channel corresponding to the at least one spectrum
Lt; / RTI >
The spectrum detector,
Passing the radio frequency (RF) input signal through each of the wideband filter and the narrowband filter to sense the at least one spectrum from the radio frequency (RF) input signal,
If the at least one spectrum is not detected, a cognitive radio system for passing the radio frequency (RF) input signal back through each of the wideband and narrowband filters to continuously detect the at least one spectrum. Multipath Spectrum Detection Device. delete The method of claim 1,
The filtering band of the broadband filter is,
And a multipath spectrum detection device for a cognitive radio system equal to a band usable by the cognitive radio system. The method of claim 1,
The narrowband filter,
Multipath spectrum detection apparatus for a cognitive radio system that can be configured with at least one, the center frequency and the bandwidth is variable. The method of claim 1,
The processor comprising:
Control signal generator for generating a control signal based on the result of the adaptive spectrum detection algorithm to adaptively adjust the center frequency and bandwidth of the narrowband filter
Lt; / RTI >
The adaptive spectrum detection algorithm,
And multipath spectrum detection apparatus for a cognitive radio system for repeatedly passing the radio frequency (RF) input signal through at least one of the wideband filter and the narrowband filter. 6. The method of claim 5,
The spectrum detector,
Multipath spectrum detection apparatus for a cognitive radio system for adjusting the center frequency and bandwidth of the narrowband filter in accordance with a control signal received from the processor. The method of claim 1,
The processor comprising:
Multipath spectrum detection apparatus for a cognitive radio system for determining the occupied state of the channel and the type of the channel by a cyclo-stationary algorithm. A multipath spectrum detection device for determining an occupation state of a channel;
A MAC module for allocating at least one usable spectrum band based on the occupied state of the channel; And
PHY module for establishing a channel according to the at least one assigned spectral band
Cognitive wireless system comprising a. 9. The method of claim 8,
The multipath spectrum detection device,
A spectrum detector for sensing at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter; And
A processor determining an occupation state of the channel corresponding to the at least one spectrum
Cognitive wireless system comprising a. 10. The method of claim 9,
The spectrum detector,
A cognitive radio system for sensing the at least one spectrum from the radio frequency (RF) input signal by passing the radio frequency (RF) input signal through each of the wideband filter and the narrowband filter. 10. The method of claim 9,
The narrowband filter,
A cognitive radio system designed to filter well-known signals and having a predetermined filtering band. 10. The method of claim 9,
The processor comprising:
Control signal generator for generating a control signal for adaptively adjusting the center frequency and bandwidth of the narrowband filter
Cognitive wireless system comprising a. The method of claim 12,
The spectrum detector,
Cognitive radio system for adjusting the center frequency and bandwidth of the narrowband filter in accordance with a control signal received from the processor. 9. The method of claim 8,
The MAC module,
A cognitive radio system for setting the priority of the channel based on the occupancy state of the channel and allocating the at least one spectrum band according to the priority. In the multi-path spectrum detection method for a cognitive radio system,
Sensing at least one spectrum from a radio frequency (RF) input signal using at least one of a wideband filter and a narrowband filter; And
Determining an occupation state of a channel corresponding to the at least one spectrum
Lt; / RTI >
Sensing the at least one spectrum comprises:
Sensing the at least one spectrum from the radio frequency (RF) input signal by passing the radio frequency (RF) input signal through each of the wideband filter and the narrowband filter; And
If the at least one spectrum is not detected, passing the radio frequency (RF) input signal back through the respective wideband and narrowband filters to continuously detect the at least one spectrum
Multipath spectrum detection method for a cognitive radio system comprising a. delete 16. The method of claim 15,
The filtering band of the broadband filter is,
Multipath spectrum detection method for a cognitive radio system equal to a band usable by the cognitive radio system. 16. The method of claim 15,
The narrowband filter,
A multipath spectrum detection method for a cognitive radio system, wherein the center frequency and bandwidth are variable, and may be configured as at least one. 16. The method of claim 15,
Generating a control signal to adaptively adjust the center frequency and bandwidth of the narrowband filter
Multipath spectrum detection method for a cognitive radio system further comprising. 20. The method of claim 19,
Sensing the at least one spectrum comprises:
And detecting the at least one spectrum by adjusting a center frequency and a bandwidth of the narrowband filter according to the control signal.

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