JP4319656B2 - Receiver, radio frame channel determination method, and radio frame channel determination program - Google Patents

Description

  The present invention relates to a receiver, a radio frame channel determination method, and a radio frame channel determination program, and in particular, a receiver that receives a plurality of radio frames having different frequency bands, a radio frame channel determination method, and a radio frame The present invention relates to a channel determination program.

  Conventionally, “IEEE802.11a wireless communication system” and “IEEE802.11g wireless communication system” have been used as wireless LAN standards. In these wireless communication systems, communication is performed using a plurality of channels having a certain frequency bandwidth. Hereinafter, this constant frequency bandwidth is referred to as a first frequency bandwidth, a plurality of channels are referred to as first channels 1 to n, and a mode in which communication is performed using one of the first channels 1 to n is referred to as a mode. This is referred to as a first communication mode. In other words, it can be said that the “IEEE802.11a wireless communication system” and the “IEEE802.11g wireless communication system” communicate in the first communication mode.

  However, since communication traffic increases with the further spread of wireless LAN in the future and an increase in the amount of communication data, a wireless communication system (hereinafter referred to as wireless communication system A) that performs communication in the first communication mode. An effective throughput higher than the effective throughput is required.

  Therefore, a second communication mode that can realize an effective throughput higher than the effective throughput of the first communication mode is newly provided, and a wireless communication system that performs communication using both the first communication mode and the second communication mode (hereinafter referred to as wireless communication). Called communication system B). The second communication mode used in the radio communication system B is a plurality of channels (hereinafter referred to as second frequency modes) having a frequency bandwidth (hereinafter referred to as second frequency bandwidth) that is twice the first frequency bandwidth. A communication mode in which communication is performed using a channel).

  As described above, in the wireless communication system B, communication with a high effective throughput is achieved by using the second channel having a frequency bandwidth twice that of the first channels 1 to n for communication.

  However, in the radio communication system B using both the second communication mode and the first communication mode, radio frames having different frequency bands are arbitrarily used for communication. Therefore, a receiver using this new radio communication system identifies whether the received radio frame is in the first communication mode or the second communication mode, and in which channel of each communication mode it has been transmitted. The radio frame must be demodulated with a demodulation method suitable for the identified communication mode and channel.

  In such a case, the conventional receiver demodulates the communication mode identifier inserted into the radio frame and identifies the communication mode of the received radio frame. Therefore, it is impossible to identify which communication mode is used until the communication mode identifier is demodulated. Therefore, in the conventional receiver, it is necessary to prepare reception circuits corresponding to the first and second communication modes, respectively, and to demodulate the communication mode identifier in each reception circuit. Therefore, the conventional receiver has to have a receiving circuit for each communication mode, and there is a problem that the circuit scale of the entire receiver is enlarged.

Therefore, the receiver shown in Patent Document 1 multiplies the received signal by a matched filter coefficient for each sample, and then performs phase rotation calculation to detect timing for each of the first channels 1 to n, and to determine by peak detection. Is used to identify the first channels 1 to n. Even when the first communication mode and the second communication mode are used in combination, the timing detection unit identifies the signal with reference to the received signal level, so that either the first communication mode or the second communication mode is used. And which channel of each communication mode is used for transmission. As a result, the receiver does not need to have a receiving circuit for each communication mode, and the circuit scale can be reduced.
JP-A-2005-72872 (page 8, page 9, FIG. 2)

  However, as in the invention of Patent Document 1, when identifying the communication mode and channel, simply determining the signal level of the received radio frame identifies the channel accurately in an environment where an interference signal arrives. It is difficult. Therefore, there is a problem that the accuracy of identifying the communication mode and the channel is poor.

  Therefore, in the present invention, whether the received radio frame is in the first communication mode or the second communication mode, and in which channel of the first channels 1 to n is transmitted in the first communication mode. An object of the present invention is to provide a receiver capable of accurately identifying, a radio frame channel determination method, and a radio frame channel determination program.

  To achieve the above object, the receiver of the present invention includes a channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or the channel an antenna that receives a radio frame transmitted in one of channels c having a second frequency bandwidth that is a combination of the frequency bandwidth of a and the channel b, and a frequency conversion that converts the frequency of the radio frame received by the antenna Based on the digital signal output from the A / D converter, the A / D converter that converts the radio frame output from the frequency converter from an analog signal to a digital signal, A detection unit for detecting a head position and a channel used for transmission of the radio frame; and a head position of the radio frame detected by the detection unit; A demodulator that demodulates the radio frame based on a channel used for transmitting the radio frame, and the detector outputs a first correlation power value from the known signal information of the received radio frame A first matched filter; a second matched filter that outputs a second correlation power value from the known signal information of the received radio frame; and adding the first correlation power value and the second correlation power value The subtracter for subtracting the second correlation power value from the first correlation power value, the timing of the peak value included in the addition signal output from the adder, and the start position of the radio frame. Timing detection means for detecting; a divider for calculating a power ratio between the addition signal from the adder and the subtraction signal from the subtractor; timing of the peak value; the subtraction signal; Based on power ratio, wherein the radio frame the receiving channel a, characterized in that it comprises a communication channel detecting means for detecting one in whether the transmission of the channel b, or the channel c.

  Further, the receiver of the present invention includes a channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or the channel a and the channel b. An antenna that receives a radio frame transmitted through one of the channels c having the second frequency bandwidth combined with the frequency bandwidth, a frequency converter that converts the frequency of the radio frame received by the antenna, and the frequency conversion An A / D converter for converting a radio frame output from the analog signal into a digital signal, and a start position of the radio frame and the radio frame based on the digital signal output from the A / D converter A detection unit for detecting a channel used for transmission of the radio frame, a start position of the radio frame detected by the detection unit, and transmission of the radio frame And a demodulator that demodulates the radio frame based on the channel used for the calculation, and the detector calculates a first correlation power value and a first phase value from known signal information of the received radio frame A first matched filter, a second matched filter that calculates a second correlated power value and a second phase value from known signal information of the received radio frame, the first correlated power value, and the first An adder that adds two correlation power values, a subtracter that subtracts the second correlation power value from the first correlation power value, the addition signal from the adder, and the subtraction signal from the subtractor A divider for calculating a power ratio, a phase value subtractor for calculating a phase difference between the first phase value and the second phase value, and timing of a peak value included in an addition signal output from the adder And the beginning of the radio frame The received radio frame is transmitted by any one of the channel a, the channel b, and the channel c based on the timing detection means for detecting the position and the timing of the peak value, the power ratio, and the phase difference. The communication mode detecting means for detecting whether or not the communication mode is detected.

  The radio frame channel determination method of the present invention includes a channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or the channel a. A method of determining the channel of a radio frame transmitted by any one of channels c having a second frequency bandwidth combined with the frequency bandwidth of the channel b, the radio channel received by a first matched filter A first correlation power value is calculated from the known signal information, a second correlation power value is calculated from the known signal information of the received radio frame by a second matched filter, and the first correlation power value and the first correlation power value are calculated. 2 is added to calculate the addition signal, the second correlation power value is subtracted from the first correlation power value to calculate a subtraction signal, and the addition is performed. When the power ratio is equal to or greater than a certain value at the timing of the peak value detected from the addition signal, the power ratio is determined to be a radio frame of the channel c, and the power ratio is constant. If it is less than a value and the subtraction signal is greater than or equal to a certain value, it is determined that the channel a is a radio frame, the power ratio is less than or equal to a certain value, and the subtraction signal is less than or equal to a certain value , It is determined that it is a radio frame of the channel b.

  The radio frame channel determination method of the present invention includes a channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or the channel a. A method of determining the channel of a radio frame transmitted by any one of channels c having a second frequency bandwidth combined with the frequency bandwidth of the channel b, the radio channel received by a first matched filter The first correlation power value and the first phase value are calculated from the known signal information, and the second correlation power value and the second phase value are calculated from the known signal information of the received radio frame by the second matched filter. And adding the first correlation power value and the second correlation power value to calculate an added signal, and subtracting the second correlation power value from the first correlation power value. Calculating a subtraction signal, calculating a power ratio between the addition signal and the subtraction signal, calculating a phase difference between the first phase value and the second phase value, and calculating a peak value detected from the addition signal. When the power ratio is equal to or greater than a certain value at the timing and the phase difference is a certain value, it is determined that the channel c is a radio frame, and the power ratio is equal to or less than the certain value or the phase difference is If it is not a constant value and the subtraction signal is greater than or equal to a certain value, it is determined that the channel a is a radio frame, and the power ratio is less than or equal to a certain value or the phase difference is not a certain value, and When the subtracted signal is equal to or less than a predetermined value, it is determined that the frame is a radio frame of the channel b.

  The channel determination program for a radio frame according to the present invention includes a channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and adjacent to the channel a, or the channel a. The first matched filter and the second matched filter calculate from the known signal information of the radio frame transmitted in any one of the channels c having the second frequency bandwidth combined with the frequency bandwidth of the channel b. A program for determining the channel based on a correlation power value and a second correlation power value, and a function of calculating an addition signal by adding the first correlation power value and the second correlation power value A function of subtracting the second correlation power value from the first correlation power value to calculate a subtraction signal, a function of calculating a power ratio of the addition signal and the subtraction signal, If the power ratio is greater than or equal to a certain value at the timing of the peak value detected from the arithmetic signal, it is determined that the channel c is a radio frame, the power ratio is less than or equal to the certain value, and the subtraction signal is a certain value. If it is above, it is determined that the frame is a radio frame of channel a, and if the power ratio is equal to or less than a certain value and the subtraction signal is equal to or less than a certain value, it is determined to be a radio frame of channel b. It is characterized by having a function.

  The channel determination program for a radio frame according to the present invention includes a channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and adjacent to the channel a, or the channel a. The first matched filter and the second matched filter calculate from the known signal information of the radio frame transmitted in any one of the channels c having the second frequency bandwidth combined with the frequency bandwidth of the channel b. A program for determining the channel based on a correlation power value, a first phase value, a second correlation power value, and a second phase value, wherein the first correlation power value and the second correlation power value A function of adding a correlation power value to calculate an addition signal; a function of subtracting the second correlation power value from the first correlation power value to calculate a subtraction signal; and the addition signal and the subtraction signal In the function for calculating the power ratio, the function for calculating the phase difference between the first phase value and the second phase value, and the timing of the peak value detected from the addition signal, the power ratio is a certain value or more. If the phase difference is a constant value, it is determined that the frame is a radio frame of the channel c, the power ratio is equal to or less than a constant value, or the phase difference is not a constant value, and the subtraction signal is When it is greater than or equal to a certain value, it is determined that the frame is a radio frame of channel a, and the power ratio is less than or equal to a certain value or the phase difference is not a certain value and the subtraction signal is less than or equal to a certain value And a function of determining that the frame is a radio frame of the channel b.

  The receiver according to the present invention transmits the received radio frame in any one of the first communication mode or the second communication mode, and in which channel of the first channels 1 to n when the received radio frame is the first communication mode. Can be accurately identified.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a radio frame transmitted and received in the first communication mode will be described with reference to FIG. The radio frame in the first communication mode is transmitted / received using the first channels 1 to n. FIG. 1 shows radio frames transmitted and received using the first channel 1 and the first channel 2, but the radio frame configurations of the first channels 1 to n are the same. A configuration of a radio frame using channel 1 will be described. Here, of the first channels 1 and 2, the lower frequency is the first channel 1 and the higher frequency is the first channel 2.

  The radio frames transmitted and received on the first channel 1 shown in FIG. 1 are, in order from the beginning, the “known symbol for the first channel 1” frame 111, the “control information for the first channel 1” frame 112, and the “data for the first channel 1”. The frame 113 is composed of three subframes. Among these, the “known symbol for the first channel 1” frame 111 is a frame used for frame synchronization detection, gain adjustment, frequency offset compensation, and propagation path estimation. The “first channel 1 control information” frame 112 includes control information such as a data modulation scheme, coding rate, and data frame length, and also includes a communication mode identifier. The last “first channel 1 data” frame 113 is composed of a data string to be transmitted.

  Next, radio frames transmitted and received in the second communication mode will be described using FIG. In the second communication mode, transmission / reception is performed using a combination of two channels having adjacent frequencies among the first channels 1 to n as the second channel. Since the radio frame configuration in the second communication mode is the same regardless of which of the two channels, the first channel 1 to n, the channel obtained by combining the first channel 1 and the first channel 2 is the second channel here. A configuration of a radio frame using the second channel A will be described.

  The radio frame shown in FIG. 2 has a “first channel 1 known symbol” frame 111 transmitted at the beginning at the first channel 1 and a “first channel 2 known” transmitted at the first channel 2 in parallel therewith. It has a “symbol” frame 121. Behind these “known symbols for first channels 1 and 2” frames 111 and 121 are “control information for first channel 1” frame 112 and “control information for first channel 2” transmitted on the respective channels. A frame 122 follows, followed by a “second channel known symbol” frame 211 and a “second channel data” frame 212 transmitted on the second channel A.

  First, “known symbols for first channels 1 and 2” frames 111 and 121 and “control information for first channels 1 and 2” frames 112 and 121 are used in radio frames transmitted and received in the first communication mode. It is a subframe of the same configuration. As described above, since the radio channel of the second channel A includes the known symbol frame for the first channel and the control information frame for the first channel, even if the receiving circuit can receive only the first communication mode, By demodulating the subframe, the radio frame of the second channel A can be recognized without being determined as an interference signal.

  Next, the “second channel known symbol” frame 211 is a frame used for gain adjustment, frequency offset compensation, and propagation path estimation of a radio frame transmitted and received in the second communication mode. The subsequent “second channel control information” frame 212 includes control information such as the modulation method, coding rate, and data frame length of the second channel data. The last “second channel data” frame 213 is composed of a data string to be transmitted.

  The present invention relates to a receiver for identifying a channel of a first communication mode, a second communication mode, and a first communication mode, and in each of the following embodiments, a first communication mode using the first channel 1 (hereinafter referred to as a first communication mode). , Referred to as the first communication mode 1), the first communication mode using the first channel 2 (hereinafter referred to as the first communication mode 2), and the second communication mode using the second channel A. A receiver that detects the communication mode used for the received radio frame from the communication modes will be described.

  Next, the receiver according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows a schematic configuration of the receiver according to the first embodiment.

  The receiver shown in FIG. 3 includes an antenna 10 that receives a high-frequency radio signal, a frequency converter 20 that converts a signal received by the antenna 10 into an intermediate frequency signal, and an analog signal that is output from the frequency converter 20. A / D converter 30 for converting from a digital signal to a digital signal, detection unit 40 for detecting the timing and communication mode of the digital signal output from the A / D converter 30, and detection results and A / D conversion of the detector 40 A demodulator 50 that demodulates received data based on the digital signal output from the unit 30 is provided. The present invention relates to communication mode detection executed in the detection unit 40 of the receiver described above. Therefore, the configuration and operation of the detection unit 40 will be described in detail below.

  FIG. 4 shows a configuration of the detection unit 40 according to the first embodiment. The detection unit 40 adds the correlation power values SIG1 and SIG2 output from the first channel 1 matched filter 1, the first channel 2 matched filter 2, and the first channels 1 and 2 matched filters 1 and 2. The adder 3 and the subtracter 4 to be subtracted, the time synchronization circuit 5 for detecting the timing of the received frame from the addition result of the adder 3, and the communication mode based on the timing output from the time synchronization circuit 5 and the addition / subtraction result A communication mode detection unit 6 that performs identification is provided. The communication mode detection unit 6 includes a divider 61 described later and a communication mode determination circuit 62 that determines a communication mode. Then, the timing output from the time synchronization circuit 5 and the detection result of the communication mode detector 6 are output to the demodulator 50 at the subsequent stage.

  Next, the configuration of the detection unit 40 will be described in detail with reference to FIGS. 4 to 6. First, the first channel 1 matched filter 1 shown in FIG. 4 has a complex amplitude value of a time synchronization symbol or a propagation path estimation symbol included in the “first channel 1 known symbol” frame 111 as a coefficient. Then, correlation processing with the signal input from the preceding A / D conversion unit 30 is performed, and a correlation power value SIG1 is output. Similarly to the matched filter 1 for the first channel 1, the matched filter 2 for the first channel 2 is also a time synchronization symbol or a propagation path estimation symbol included in the “known symbol for the first channel 2” frame 121. Of the complex amplitude value is used as a coefficient, and correlation processing with a signal input from the preceding A / D conversion unit 30 is performed, and as a result, a correlation power value SIG2 is output.

  In the following, a frame synchronization timing detection method using a matched filter having a complex amplitude value of a symbol for time synchronization as a coefficient will be described. In the “known symbol for first channel 1” frame 111, for example, time synchronization symbols having frequency components as shown in FIG. 5 are periodically inserted 10 times. On the other hand, in the “known symbol for first channel 2” frame 121, for example, time synchronization symbols having frequency components as shown in FIG. 6 are periodically inserted 10 times. Therefore, the radio frame transmitted in the first communication mode 1 periodically has 10 time synchronization symbols having the frequency components shown in FIG. 5, and the radio frame transmitted in the first communication mode 2 is the same as that shown in FIG. 10 time synchronization symbols having the frequency components shown in FIG.

  Therefore, when a radio frame transmitted in the first communication mode 1 is received, only the correlation power value SIG1 that is the output of the first channel 1 matched filter 1 periodically includes a peak value 10 times. When a radio frame transmitted in the first communication mode 2 is received, the peak value is periodically included 10 times only in the correlation power value SIG2 that is the output of the first channel 2 matched filter 2.

  Also, the radio frame transmitted in the second communication mode periodically has 10 time synchronization symbols having the frequency components of the first channel 1 and the first channel 2 as shown in FIG. Accordingly, when a radio frame transmitted in the second communication mode is received, the correlation power values SIG1 and SIG2 that are the outputs of the matched filters 1 and 2 for the first channel 1 and the first channel 2 are periodically displayed. The 10th peak value is included.

  Next, the adder 3 adds the correlation power values SIG1 and SIG2, and outputs this addition signal SIG3 to the time synchronization circuit 5 and the communication mode detection unit 6. The subtractor 4 subtracts SIG2 from the correlation power value SIG1 and outputs this subtraction signal SIG4 to the communication mode detection unit 6.

  The time synchronization circuit 5 to which the addition signal SIG3 is input, based on the addition signal SIG3, the start position of the radio frame (hereinafter referred to as frame synchronization timing) and the peak value timing (hereinafter referred to as peak timing). ) To detect the frame synchronization timing to the demodulator 50 and the peak timing to the communication mode detector 6.

  In order to detect the frame synchronization timing, the time synchronization circuit 5 first detects the maximum power value (peak value) within one cycle in which the time synchronization symbol is inserted, and based on this, determines the threshold value TH1. calculate. This threshold value TH1 may be about 80% of the peak value, or may be 80% of the average value of power for several cycles. Next, the power value of the addition signal SIG3 is compared with the threshold value TH1, and the timing at which the power value of the addition signal SIG3 is equal to or greater than the threshold value TH1 is detected. This timing is the peak timing. Since the time synchronization symbol is periodically inserted into the known symbols 111 and 121 ten times, this peak timing is detected ten times. The time synchronization circuit 5 detects the frame synchronization timing based on the peak timing and the period in which the time synchronization symbol is inserted. Here, the peak timing of the output of the matched filter having the complex amplitude value of the symbol for time synchronization as a coefficient is detected to detect the frame synchronization timing, but the matched filters 1 and 2 for the first channels 1 and 2 are detected. In other words, a method other than those described above may be used, for example, a matched filter having a complex amplitude value of a propagation path estimation symbol as a coefficient. The time synchronization circuit 5 notifies the communication mode detection unit 6 of the peak timing, but may instead notify the frame synchronization timing.

  Next, the communication mode detection unit 6 will be described. The communication mode detection unit 6 includes a divider 61 and a communication mode determination circuit 62 that determines a communication mode. First, to the divider 61, the addition signal SIG3 is input from the adder 3, and the subtraction signal SIG4 is input from the subtractor 4. The divider 61 calculates a division signal SIG5 that is a power ratio between the addition signal SIG3 and the subtraction signal SIG4, and outputs it to the communication mode determination circuit 62. The communication mode determination circuit 62 receives the division signal SIG5 from the divider 61, the subtraction signal SIG4 from the subtractor 4, and the peak timing from the time synchronization circuit 5. The communication mode determination circuit 62 holds a threshold value TH2 set in advance based on experimental results and the like, and compares the division signal SIG5 with the threshold value TH2 at the peak timing. Moreover, the positive / negative determination of the subtraction signal SIG4 is also performed, and the communication mode is determined based on the comparison result and the positive / negative determination result. A detailed determination procedure of the communication mode will be described later.

Next, the operation of the detection unit 40 will be described with reference to FIGS. 4 and 8 to 10.
First, operation | movement of the detection part 40 is demonstrated using FIG. When the radio frame converted into the digital signal by the A / D conversion unit 30 is input to the first channel 1 matched filter 1 and the first channel 2 matched filter 2, each matched first channel 1 and 2 matched filter is used. The filters 1 and 2 perform correlation processing on the input radio frame and output the correlation power values SIG1 and SIG2 to the adder 3 and the subtractor 4. The adder 3 to which the correlation power values SIG1 and SIG2 are input adds these signals and outputs the addition signal SIG3 to the time synchronization circuit 5 and the communication mode detection unit 6. Further, the subtractor 4 to which the correlation power values SIG1 and SIG2 are input subtracts SIG2 from SIG1, and outputs a subtraction signal SIG4 to the communication mode detection unit 6.

  Next, the time synchronization circuit 5 to which the addition signal SIG3 is input detects the frame synchronization timing and the peak timing based on the threshold determination, outputs the frame synchronization timing to the demodulation unit 50, and outputs the peak timing to the communication mode detection unit 6. Output. When the addition signal SIG3, the subtraction signal SIG4, and the peak timing are input to the communication mode detection unit 6, first, in the divider 61 in the communication mode detection unit 6, the addition signal SIG3 is divided from the subtraction signal SIG4, and the resulting division signal SIG 5 is input to communication mode determination circuit 62. The communication mode determination circuit 62 receives the subtraction signal SIG4 and the peak timing together with the division signal SIG5. The communication mode determination circuit 62 determines whether the division signal SIG5 and the threshold value TH2 are compared and whether the subtraction signal SIG4 is positive or negative. Determine the communication mode.

  Hereinafter, the determination of the communication mode will be described with reference to FIGS. FIG. 8 is a diagram illustrating waveforms of input / output signals of the adder 3, the subtracter 4, and the divider 61 when a radio frame in the second communication mode is received. FIG. 9 is a diagram illustrating waveforms of input / output signals of the adder 3, the subtracter 4, and the divider 61 when a radio frame in the first communication mode 1 is received. Here, first, the signal waveform when the second communication mode radio frame is received will be described with reference to FIG. 8, and then the signal waveform when the first communication mode 1 radio frame is received will be described with reference to FIG. Finally, the procedure for determining the communication mode based on these signal waveforms will be described.

  First, a case where a radio frame in the second communication mode is received will be described with reference to FIG. When a radio frame in the second communication mode is input to the detection unit 40, the matched filter 1 having the time synchronization symbol of the first channel 1 in the complex amplitude value and the time synchronization symbol of the first channel 2 are converted to the complex amplitude value. The matched filter 2 has a correlation process on the input radio frame and outputs correlation power values SIG1 and SIG2. At this time, both of the correlation power values SIG1 and SIG2 periodically have a peak value 10 times.

  The adder 3 adds the correlation power values SIG1 and SIG2 and outputs the resultant addition signal SIG3 to the divider 61. In this case, the addition signal SIG3 has a value obtained by adding the peak value of the correlation power value SIG1 and the peak value of the correlation power value SIG2 as a peak value, and is a signal in which this peak value is periodically inserted 10 times. The subtractor 4 subtracts SIG2 from the correlation power value SIG1 and outputs the resulting subtraction signal SIG4 to the divider 61 of the communication mode detection unit 6. In this case, since the correlation power value SIG1 and the correlation power value SIG2 have substantially the same peak value at substantially the same peak timing, the subtraction signal SIG4 is a substantially flat signal having no peak value.

  Next, the divider 61 calculates a division signal SIG5 that is a power ratio between the input addition signal SIG3 and the subtraction signal SIG4, and outputs it to the communication mode determination circuit 62. In this case, since the addition signal SIG3 periodically has a peak value of 10 times and the subtraction signal SIG4 is a substantially flat signal, the calculated division signal SIG5 has a peak value of 10 times for each same period as the addition signal SIG3. It becomes a signal with.

  Next, a case where a radio frame in the first communication mode 1 is received will be described using FIG. When the first communication mode 1 radio frame is input, the first channel 1 matched filter 1 and the first channel 2 matched filter 2 output correlation power values SIG1 and SIG2. At this time, the correlation power value SIG1 output from the first channel 1 matched filter 1 periodically has a peak value 10 times, but the correlation power value SIG2 output from the first channel 2 matched filter 2 is The signal is almost flat.

  The adder 3 adds the correlation power values SIG1 and SIG2 and outputs the resultant addition signal SIG3 to the divider 61. In this case, since the adder 3 periodically adds the correlation power value SIG1 having the peak value 10 times and the substantially flat correlation power value SIG2, the addition signal SIG3 has a waveform substantially the same as the correlation power value SIG1. It becomes a signal with. The subtractor 4 subtracts SIG2 from the correlation power value SIG1 and outputs the resulting subtraction signal SIG4 to the divider 61 of the communication mode detection unit 6. In this case, since the subtracter 4 subtracts the substantially flat correlation power value SIG2 from the correlation power value SIG1 having a peak value 10 times periodically, the subtraction signal SIG4 also has a waveform substantially the same as the correlation power value SIG1. It becomes a signal with.

  Next, the divider 61 calculates a division signal SIG5, which is a power ratio between the input addition signal SIG3 and the subtraction signal SIG4, and outputs it to the comparator. In this case, since the addition signal SIG3 and the subtraction signal SIG4 are substantially the same waveform signals as the correlation power value SIG1, the calculated division signal SIG5 is a substantially flat signal.

  Next, the procedure for determining the communication mode will be described using the flowchart of FIG. The communication mode determination circuit 62 starts determining the communication mode when the division signal SIG5 is input from the divider 61, the subtraction signal SIG4 is input from the subtractor 4, and the peak timing is input from the time synchronization circuit 5.

  First, the communication mode determination circuit 62 compares the division signal SIG5 with the threshold value TH2 at the peak timing (step 101). As described above, when the radio frame in the first communication mode 1 or 2 is received, the division signal SIG5 is a substantially flat signal (see FIG. 9), and when the radio frame in the second communication mode is received, the division signal SIG5 is a signal having a peak value of 10 times (see FIG. 8). Therefore, if the division signal SIG5 is greater than the threshold value TH2 as a result of comparison between the division signal SIG5 and the threshold value TH2, the communication mode determination circuit 62 determines that the radio frame has been transmitted in the second communication mode and notifies the demodulator 50.

  On the other hand, when the division signal SIG5 is smaller than the threshold value TH2, the communication mode determination circuit 62 determines that the wireless frame has been transmitted in the first communication mode, and further transmitted in the first communication mode 1 or in the first communication mode 2. Determine if it was sent. Therefore, the sign of the subtraction signal SIG4 is determined at the peak timing (step 102). When a radio frame in the first communication mode 1 is received, the subtraction signal SIG4 has a positive peak value (see FIG. 9). On the other hand, when the radio frame of the first communication mode 2 is received, the subtraction signal SIG4 has a negative peak because the order of subtraction performed by the subtracter 4 is reversed from that when the radio frame of the first communication mode 1 is received. Has a value. Accordingly, the communication mode determination circuit 62 determines that the radio frame is transmitted in the first communication mode 1 if the subtraction signal SIG4 has a positive peak value, and determines that the radio frame is transmitted in the first communication mode 2 if it has a negative peak value. Judge that it was sent. The communication mode detection unit 6 detects the communication mode of the received radio frame according to the above-described procedure, and notifies the demodulation unit 50 of the result.

  As described above, according to the first embodiment, the threshold value determination of the division signal SIG5 that is the power ratio of the addition signal SIG3 and the subtraction signal SIG4 is performed at the peak timing, so that even in an environment where an interference signal arrives, the threshold value is high. The communication mode can be detected with high accuracy. Further, since the communication mode can be detected without demodulating the control frame including the communication mode identifier, there is no plurality of demodulation circuits for each communication mode, and the circuit scale can be reduced and the power consumption can be suppressed. . Furthermore, since the “first channel 1 and 2 known symbols” frames 111 and 121 at the head of the radio frame are used for communication mode detection, the communication mode can be quickly identified.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In order to reduce the PAPR (Peak to Average Power Ratio) of the radio signal, the “known symbol for the first channel 1” frame 111 and the “known symbol for the first channel 2” frame 121 of the radio frame transmitted and received in the second communication mode. In some cases, an arbitrary phase difference is given. In this embodiment, a receiver in a radio communication system that transmits and receives radio frames in the second communication mode in which an arbitrary phase difference is given between the “first channel 1 and 2 known symbols” frames 111 and 121 in this way. explain. In the following, for simplification of description, the phase difference between the “first channel 1 and 2 known symbols” frames 111 and 121 is 90 degrees.

  In the receiver according to the present embodiment, the detection unit 40 uses the phase difference between the “first channel 1 and 2 known symbols” frames 111 and 121 to detect the communication mode. Since it is the same as an example, the same code | symbol is attached | subjected to the same component and description is abbreviate | omitted.

  FIG. 11 shows the configuration of the detection unit 40 according to the second embodiment. The detection unit 40 includes a point that each of the matched filters 1 and 2 for the first channels 1 and 2 outputs the phase value of the input signal, and a new phase value subtractor 7 that subtracts each phase value. The communication mode determination circuit 62 uses the phase value to determine the communication mode, but the rest of the configuration is the same as that of the detection unit 40 shown in FIG.

  The matched filter 1 for the first channel 1 and the matched filter 2 for the first channel 2 shown in FIG. 11 have substantially the same configuration as the matched filter shown in FIG. 4, but when the radio frame is input, the power values SIG1 and SIG2 are obtained. The difference is that the signals are output to the adder 3 and the subtracter 4 and the phase values SIG6 and SIG7 are output to the phase value subtracter 4 described later.

  Next, the phase value subtracter 7 provided in the detection unit 40 receives the phase value SIG7 output from the first channel 2 matched filter 2 from the phase value SIG6 input from the first channel 1 matched filter 1. And the absolute value of the obtained phase difference is output to the communication mode determination circuit 62 as a phase subtraction value SIG8 as a subtraction result.

  The communication mode determination circuit 62 performs threshold determination of the division signal SIG5 input from the divider 61 and positive / negative determination of the subtraction signal SIG4 input from the subtractor 4, and uses the phase subtraction value SIG8 based on experiments and the like in advance. By comparing with the determined threshold values TH3 and TH4 (threshold value TH3 <threshold value TH4), it is determined whether or not the phase difference between the phase value SIG6 and the phase value SIG7 is 90 degrees. Hereinafter, this determination is referred to as phase 90 degree determination.

  In order to perform this phase 90 degree determination, the communication mode determination circuit 62 first subtracts 90 degrees from the phase subtraction value SIG8. Here, since the phase difference between the “first channel 1 and 2 known symbols” frames 111 and 121 is 90 degrees, 90 degrees is subtracted from the phase subtraction value SIG8, but the phase difference is N degrees. In some cases, N degrees of the phase difference is subtracted.

  Next, the communication mode determination circuit 62 compares the value obtained by subtracting 90 degrees from the phase subtraction value SIG8 with the threshold value TH3 and the threshold value TH4, and determines whether this value is within the range of the threshold value TH3 and the threshold value TH4. . When the value obtained by subtracting 90 degrees from the phase subtraction value SIG8 is within the above range, the communication mode determination circuit 62 determines that the phase difference between the phase value SIG6 and the phase value SIG7, that is, the phase subtraction value SIG8 is 90 degrees, When it is out of the above range, it is determined that the phase subtraction value SIG8 is not 90 degrees. The communication mode determination circuit 62 determines the communication mode used for transmission of the radio frame based on the determination result of the phase 90 degrees, the threshold determination of the division signal SIG5, and the positive / negative determination of the subtraction signal SIG4, and the result is Output to demodulator 50.

Next, operation | movement of the detection part 40 which concerns on a present Example is demonstrated using FIG.11 and FIG.12.
First, operation | movement of the detection part 40 is demonstrated using FIG. When the radio frame converted into the digital signal by the A / D conversion unit 30 is input to the first channel 1 matched filter 1 and the first channel 2 matched filter 2, each matched first channel 1 and 2 matched filter is used. Filters 1 and 2 perform correlation processing on the input radio frame, output correlation power values SIG1 and SIG2 to adder 3 and subtractor 4, and output phase values SIG6 and SIG7 to phase subtractor 4. To do.

  The adder 3 to which the correlation power values SIG1 and SIG2 are input adds these signals and outputs the addition signal SIG3 to the time synchronization circuit 5 and the communication mode detection unit 6. On the other hand, the subtractor 4 to which the correlation power values SIG1 and SIG2 are input subtracts SIG2 from SIG1 and outputs a subtraction signal SIG4 to the communication mode detection unit 6. The phase subtractor 4 to which the phase values SIG6 and SIG7 are input subtracts SIG7 from SIG6 and outputs a phase subtraction value SIG8, which is an absolute value of the obtained phase difference, to the communication mode detection unit 6.

  The time synchronization circuit 5 to which the addition signal SIG3 is input detects the frame synchronization timing and the peak timing based on the threshold determination, outputs the frame synchronization timing to the demodulation unit 50, and outputs the peak timing to the communication mode detection unit 6.

  When the addition signal SIG3, the subtraction signal SIG4, the phase subtraction value SIG8, and the peak timing are input to the communication mode detection unit 6, first, in the divider 61 in the communication mode detection unit 6, the addition signal SIG3 and the subtraction signal SIG4 are divided. The resulting division signal SIG5 is input to the communication mode determination circuit 62. The communication mode determination circuit 62 to which the subtraction signal SIG4, the phase subtraction value SIG8, and the peak timing are input together with the division signal SIG5 is based on the threshold determination of the division signal SIG5, the positive / negative determination of the subtraction signal SIG4, and the phase 90 degree determination. Determine the communication mode.

  Next, the procedure for determining the communication mode will be described using the flowchart of FIG.

  First, the communication mode determination circuit 62 compares the division signal SIG5 with the threshold value TH2 at the peak timing (step 101). As a result of the comparison, if the division signal SIG5 is larger than the threshold value TH2, the process proceeds to the next step, and the phase subtraction value SIG8 is determined whether or not the phase subtraction value SIG8 is 90 degrees using the threshold values TH3 and TH4 as described above. (Step 103). When it is determined that the phase subtraction value SIG8 is within the range between the threshold TH3 and the threshold TH4 (that is, 90 degrees) (Yes in step S103), it is determined that the radio frame is transmitted in the second communication mode, and the demodulator 50 is notified.

  When the division signal SIG5 is smaller than the threshold value TH2 (No in step S101) or the phase subtraction value SIG8 is not 90 degrees (No in step S103), the communication mode determination circuit 62 determines that the radio frame is in the first communication mode. It is determined that it has been transmitted, and it is further determined whether it has been transmitted in the first communication mode 1 or the first communication mode 2. Then, whether the subtraction signal SIG4 at the peak timing is positive or negative is determined (step 102). If the subtraction signal SIG4 has a positive peak value, it is determined that the radio frame has been transmitted in the first communication mode 1, and if it has a negative peak value, it is determined that it has been transmitted in the first communication mode 2. The communication mode detection unit 6 detects the communication mode of the received radio frame according to this procedure, and notifies the demodulation unit 50 of the result.

  As described above, according to the second embodiment, since the communication mode is detected using not only the power value but also the phase value, the erroneous detection is more compared with the communication mode detection using only the power value. Less highly accurate communication mode detection can be performed. Further, since the communication mode can be detected without demodulating the control frame including the communication mode identifier, there is no plurality of demodulation circuits for each communication mode, and the circuit scale can be reduced and the power consumption can be suppressed. . Furthermore, since the “first channel 1 and 2 known symbols” frames 111 and 121 at the head of the radio frame are used for communication mode detection, the communication mode can be quickly identified.

  In addition, this invention is not limited to the said Example as it is, A component can be deform | transformed and embodied in the range which does not deviate from the summary in an implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure which shows the structure of the radio | wireless frame transmitted / received in 1st communication mode. The figure which shows the structure of the radio | wireless frame transmitted / received in 2nd communication mode. The block diagram which shows the structure of the receiver which concerns on 1st Example of this invention. The block diagram which shows the structure of the detection part which concerns on 1st Example of this invention. The figure which shows the frequency component of the symbol for time synchronization SP contained in the known symbol for 1st channels. The figure which shows the frequency component of the symbol SP for time synchronization contained in the known symbol for 1st channels. The figure which shows the frequency component of the symbol SP for time synchronization contained in the radio | wireless frame of the 2nd channel A. FIG. The figure which showed the waveform of the signal input / output by the adder 3, the subtractor 4, and the divider 61, when the radio | wireless frame of a 2nd communication mode is received. The figure which showed the waveform of the signal input / output by the adder 3, the subtractor 4, and the divider 61, when the radio | wireless frame of 1st communication mode 1 is received. The flowchart which shows operation | movement of the 1st Example of this invention. The block diagram which shows the structure of the detection part which concerns on the 2nd Example of this invention. The flowchart which shows operation | movement of the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Matched filter 3 ... Adder 4 ... Subtractor 5 ... Time synchronization circuit 6 ... Communication mode detection part 61 ... Divider 62 ... Communication mode determination circuit 7 ... Subtractor for phase value 10 ... Antenna 20 ... Frequency converter 30 ... A / D converter 40 ... Detector 50 ... Demodulators 111, 121, 211 ... Known Symbol frame 112, 122 ... Control information frame 113, 123, 213 ... Data frame SP ... Time synchronization symbol SIG1, SIG2 ... Correlated power value SIG3 ... Addition signal SIG4 ... Subtraction signal SIG5 ... division signal SIG6, SIG7 ... phase value SIG8 ... phase subtraction value

Claims (9)

A channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or a second frequency obtained by combining the frequency bandwidths of the channel a and the channel b An antenna for receiving a radio frame transmitted on one of the channels c having bandwidth;
A frequency converter that converts the frequency of the radio frame received by the antenna;
An A / D converter that converts a radio frame output from the frequency converter from an analog signal to a digital signal;
Based on a digital signal output from the A / D conversion unit, a detection unit that detects a head position of the radio frame and a channel used for transmission of the radio frame;
A demodulation unit that demodulates the radio frame based on a start position of the radio frame detected by the detection unit and a channel used for transmission of the radio frame;
The detector is
A first matched filter that outputs a first correlation power value from the known signal information of the received radio frame;
A second matched filter that outputs a second correlation power value from the known signal information of the received radio frame;
An adder for adding the first correlation power value and the second correlation power value;
A subtractor for subtracting the second correlation power value from the first correlation power value;
Timing detection means for detecting the timing of the peak value included in the addition signal output by the adder and the start position of the radio frame;
A divider for calculating a power ratio of the addition signal from the adder and the subtraction signal from the subtractor;
Communication channel detection means for detecting whether the received radio frame is transmitted in the channel a, the channel b, or the channel c based on the timing of the peak value, the subtraction signal, and the power ratio; A receiver comprising: When the communication channel detection means detects that the power ratio from the divider is equal to or greater than a certain value at the timing of the peak value, the communication channel detection means determines that the channel is a radio frame of the channel c,
When it is detected that the power ratio is less than or equal to a certain value and the subtraction signal is greater than or equal to a certain value, it is determined that the radio frame is the channel a,
2. The receiver according to claim 1, wherein when it is detected that the power ratio is equal to or lower than a predetermined value and the subtracted signal is equal to or lower than a predetermined value, it is determined as a radio frame of the channel b. . A channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or a second frequency obtained by combining the frequency bandwidths of the channel a and the channel b An antenna for receiving a radio frame transmitted on one of the channels c having bandwidth;
A frequency converter that converts the frequency of the radio frame received by the antenna;
An A / D converter that converts a radio frame output from the frequency converter from an analog signal to a digital signal;
Based on a digital signal output from the A / D conversion unit, a detection unit that detects a head position of the radio frame and a channel used for transmission of the radio frame;
A demodulation unit that demodulates the radio frame based on a start position of the radio frame detected by the detection unit and a channel used for transmission of the radio frame;
The detector is
A first matched filter that calculates a first correlation power value and a first phase value from known signal information of the received radio frame;
A second matched filter that calculates a second correlation power value and a second phase value from the known signal information of the received radio frame;
An adder for adding the first correlation power value and the second correlation power value;
A subtractor for subtracting the second correlation power value from the first correlation power value;
A divider for calculating a power ratio of the addition signal from the adder and the subtraction signal from the subtractor;
A phase value subtractor for calculating a phase difference between the first phase value and the second phase value;
Timing detection means for detecting the timing of the peak value included in the addition signal output by the adder and the start position of the radio frame;
The communication mode detecting means for detecting whether the received radio frame is transmitted in the channel a, the channel b, or the channel c based on the timing of the peak value, the power ratio, and the phase difference. And a receiver. When the communication mode detection unit detects that the power ratio from the divider is equal to or greater than a certain value and the phase difference is a certain value at the timing of the peak value, Judge that there is
If the power ratio is less than a certain value or the phase difference is not a certain value and it is detected that the subtraction signal is more than a certain value, it is determined that it is a radio frame of the channel a,
When it is detected that the power ratio is less than a certain value or the phase difference is not a certain value and the subtraction signal is less than a certain value, it is determined that the frame is a radio frame of the channel b. The receiver according to claim 3. The first and second matched filters are:
A complex amplitude value of a time synchronization symbol or a propagation path estimation symbol included in the known signal information is used as a coefficient, and correlation processing with a signal input from the A / D conversion unit is performed to perform the first and second The receiver according to claim 1 or 3, wherein a correlation power value is output. A channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or a second frequency obtained by combining the frequency bandwidths of the channel a and the channel b A method of determining the channel of a radio frame transmitted on one of channels c having bandwidth,
Calculating a first correlation power value from the known signal information of the radio frame received by the first matched filter;
Calculating a second correlation power value from the known signal information of the received radio frame by a second matched filter;
Adding the first correlation power value and the second correlation power value to calculate an added signal;
Subtracting the second correlation power value from the first correlation power value to calculate a subtraction signal;
Calculating a power ratio of the addition signal and the subtraction signal;
If the power ratio is a certain value or more at the timing of the peak value detected from the added signal, it is determined that the radio frame is the channel c,
If the power ratio is less than a certain value and the subtraction signal is more than a certain value, it is determined that it is a radio frame of the channel a,
A radio frame channel determination method, wherein when the power ratio is equal to or less than a predetermined value and the subtraction signal is equal to or less than a predetermined value, the radio frame is determined to be a radio frame of the channel b. A channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or a second frequency obtained by combining the frequency bandwidths of the channel a and the channel b A method of determining the channel of a radio frame transmitted on one of channels c having bandwidth,
Calculating a first correlation power value and a first phase value from the known signal information of the radio frame received by the first matched filter;
Calculating a second correlation power value and a second phase value from the known signal information of the received radio frame by a second matched filter;
Adding the first correlation power value and the second correlation power value to calculate an added signal;
Subtracting the second correlation power value from the first correlation power value to calculate a subtraction signal;
Calculating a power ratio of the addition signal and the subtraction signal;
Calculating a phase difference between the first phase value and the second phase value;
If the power ratio is equal to or greater than a certain value at the timing of the peak value detected from the addition signal and the phase difference is a certain value, it is determined that the radio frame is the channel c,
If the power ratio is less than or equal to a certain value or the phase difference is not a certain value and the subtraction signal is greater than or equal to a certain value, it is determined to be a radio frame of the channel a;
A radio frame characterized in that if the power ratio is less than a certain value or the phase difference is not a certain value and the subtraction signal is less than a certain value, the radio frame is determined to be a radio frame of the channel b. Channel judgment method. A channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or a second frequency obtained by combining the frequency bandwidths of the channel a and the channel b Based on the first correlated power value and the second correlated power value calculated by the first matched filter and the second matched filter from the known signal information of the radio frame transmitted in any of the channels c having the bandwidth A program for determining the channel,
A function of calculating the sum signal by adding the first correlation power value and the second correlation power value;
A function of subtracting the second correlation power value from the first correlation power value to calculate a subtraction signal;
A function of calculating a power ratio of the addition signal and the subtraction signal;
If the power ratio is equal to or higher than a certain value at the timing of the peak value detected from the addition signal, it is determined that the channel c is a radio frame, the power ratio is equal to or less than a certain value, and the subtraction signal is constant. If it is greater than or equal to the value, it is determined that the frame is a radio frame of the channel a, and if the power ratio is less than or equal to a certain value and the subtraction signal is less than or equal to a certain value, it is determined that the radio frame is the channel b And a radio frame channel determination program. A channel a having a first frequency bandwidth, a channel b having the first frequency bandwidth and having a frequency band adjacent to the channel a, or a second frequency obtained by combining the frequency bandwidths of the channel a and the channel b A first correlated power value, a first phase value, a second phase value calculated by the first matched filter and the second matched filter from the known signal information of the radio frame transmitted in any one of the channels c having a bandwidth; A program for determining the channel based on a correlation power value and a second phase value,
A function of calculating the sum signal by adding the first correlation power value and the second correlation power value;
A function of subtracting the second correlation power value from the first correlation power value to calculate a subtraction signal;
A function of calculating a power ratio of the addition signal and the subtraction signal;
A function of calculating a phase difference between the first phase value and the second phase value;
When the power ratio is equal to or greater than a certain value at the timing of the peak value detected from the added signal and the phase difference is a certain value, it is determined that the channel c is a radio frame, and the power ratio is Or when the phase difference is not a constant value and the subtraction signal is a certain value or more, it is determined that the channel a is a radio frame, and the power ratio is a certain value or less A radio frame channel determination program, comprising: a function of determining that the channel b is a radio frame when the phase difference is not a constant value and the subtracted signal is a predetermined value or less.

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