WO2008010283A1 - Signal detecting apparatus - Google Patents

Abstract

A signal detecting apparatus for detecting a desired OFDM modulated signal from among received signals. The signal detecting apparatus comprises an FFT part that converts received signals to first frequency domain signals of the respective carriers; a preamble pattern generating part (51) that generates second frequency domain information of the respective carriers, based on signals which include predetermined known information, have different frequencies and different initial phases and which are obtained by multiplexing signals of a plurality of carriers; complex conjugators (52) that generate complex conjugates of the second frequency domain information for the respective carriers; complex multipliers (53) that multiply the first frequency domain signals of the respective carriers by the complex conjugates of the respective carriers generated by the complex conjugators; a complex summing amplifier (54) that adds together a part or all of multiplication outputs from the multiplying means; and a signal detecting means (an absolute value calculating part (55), a carrier detecting/determining part (56)) that calculates an absolute value of an addition result or calculates a square value of the addition result and uses a predetermined threshold value to detect/determine a desired signal.

Description

Specification

Signal detection apparatus

Technical field

[0001] The present invention relates to signal detection apparatus performs detection of the desired signal at a receiver constituting the communication device, in particular, the detection and the detection of the symbol timing of the desired signal using a known signal it relates to a signal detection apparatus for performing.

BACKGROUND

[0002] In a communication system using a CSMA (Carrier Sense Multiple Access) scheme, transmits given the known signal waveform before the signal sending data, communication devices belonging to the communication system, this known signal waveform constantly monitors whether power is present on the transmission line. Their to communication device, when detecting the presence of a known signal waveform, even without transmission if there is transmission data, and to perform the receiving operation. Further, in the case of a communication system using TDMA (Time Division Multip le Access) scheme, so that it can be synchronized with the underlying periodic contact and timing of the terminal is time division, the base station transmits a known signal waveform periodically end end in some cases, such as for synchronization by detecting the known signal waveforms. Signal waveform of such previously known is referred to as preamble, be referred to as an operation signal of the communication system of its own device to detect whether the force not be present on the transmission line carrier detection, or the carrier sense, etc. is there.

[0003] In the conventional carrier detection, communication devices simply received signal power (RSSI: Received Signal

Strength Indicator) to measure, were ヽ to determine whether based, Te signals on the measurement result. Specifically, compared with a certain threshold the measurement result of RSSI, determines that the measured value of RSSI is the signal is present is larger than the threshold value, low measured value of the RSSI is below the threshold V, the Do and signal exists, it is determined that things were the case.

[0004] Further, the signal waveform of the transmission line, constantly monitors the correlation value between the preamble signal waveform is a known waveform, determines that the signal is present if the threshold is greater than with this correlation value, whereas, by correlation value is determined that there is no signal when less than the threshold value, there a method of to detect the presence of a signal of a communication system of interest more reliably (e.g., Patent documents 1).

[0005] Furthermore, in the communication system using OFDM (Orthogonal Frequency Division Multiplexing) as the modulation method, inverse fast Fourier transform on the transmitting side (IFFT: Inverse Fast Fouri er Transform) time carrying different information to a plurality of frequency using the generates a waveform, the fast Fourier transform in the receiver side (FFT: fast Fourier transform) process for separating the information of the individual frequency by is performed. Bale processing unit calls and the like symbols in this IFFTZFFT, the FFT processing upon reception cut out a received signal using the appropriate symbol timing, it is necessary to FFT input. This also detected symbol timing preamble signal is used, the correlation values ​​of the aforementioned carrier detection as well as the received waveform at the receiving end, based on the timing of the peak position where the correlation value is maximized, the symbol timing method of detecting is used (for example, non-Patent Document 1).

[0006] Patent Document 1: JP 2005- 295085 Patent Publication (tert-page 6, Figure 1)

Non-Patent Document 1: Masahiro Moriya Shuji Kubota supervision "revised version 802.11 high-speed wireless LAN textbook" Corporation Impress, January 1, 2005, P206-212

Disclosure of the Invention

Problems that the Invention is to you'll solve

While [0007] is the force, in the detection determination by the conventional RSSI, since it is detected based only on the power, even power, such as signal and noise on other systems, career if it exceeds the threshold value detection and thus determines, that problem is likely to perform erroneous detection there ivy o

[0008] In addition, there is a method using cross-correlation and methods of using the self-correlation method using the correlation value, the autocorrelation, targeting signal is repeatedly transmitted, it multiplies the signal delayed by repetition period obtaining a correlation value by integrating the result. In contrast, the cross-correlation, determine the correlation value by integrating the multiplication results of the respective samples of the preamble signal waveform and the reception waveform already known. Generally, the detection accuracy of the multiplier circuit power Tsude good but obtained only slow and force peak timing is autocorrelation inferior cross correlation. Although it is necessary to sample number only multiplying circuit for obtaining a correlation in the cross-correlation is high detection accuracy of the timing for steep peak is obtained. Note that the autocorrelation, cross-correlation in both the, the integration requires a summing circuit for obtaining the sum of the number of samples of the multiplication result, while the detection accuracy as a longer period to obtain the correlation value becomes higher in any case , there has been a problem that the circuit scale is increased.

[0009] The present invention was made in view of the above, an object of the present invention to provide a signal detecting device that realize highly accurate carrier detection and timing detection.

Means for Solving the Problems

[0010] To solve the above problems and achieve the object, the signal detecting apparatus according to the present invention, there is provided a signal detection apparatus for detecting a desired signal modulated by Churyoku OFDM system of the received signal , a signal conversion means for converting the received signal into a frequency domain information for each carrier (the first frequency-domain signal), a predetermined known information contains and frequency and the initial phase are different, signals of a plurality of carriers multiplexed based on the coded signal, and the known frequency information generating means for generating a frequency-domain information of each carrier (the second frequency-domain information), the complex of the second frequency region information outputted from said known frequency information generating means complex conjugate generation means for generating a conjugate for each carrier, a first and a frequency domain signal, the complex conjugate and the complex conjugate every carrier generated by the generating means, the same frequency for each of the carrier Multiplication means for multiplying in frequency each other, and adding means for adding a part or all of the multiplication output by said multiplying means, then calculates a square value of the absolute values ​​or the sum of the addition result, the calculation result and previously and wherein further comprising a signal detecting means for detecting the determination of the desired signal using a defined predetermined threshold, the.

Effect of the invention

[0011] According to the present invention, it converts the preamble signal received in the frequency domain information by FFT, using the results obtained with the converted information by multiplying each complex conjugate value of the known preamble pattern Te. Thus performs carrier detection and timing determined by determining the class similarity between the received preamble signal and preamble patterns, as compared with the case of performing carrier detection, etc. using only power that used traditional , suppress the occurrence frequency with the erroneous detection, it is possible to increase the carrier detection accuracy, an effect that.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [FIG 1] FIG 1 is a diagram showing a configuration example of a side of a communication device that sends data to the communication device having a signal detection apparatus according to the present invention (transmitter). FIG. 2 is a diagram showing a configuration example of a shape state first embodiment of a communication apparatus having a signal detection apparatus according to the present invention (the receiver).

Figure [3] 3, FIG. 4 is a diagram illustrating a configuration example of a carrier detection timing determination unit of the first embodiment, showing a configuration example of a carrier detection timing judgment unit of the second embodiment in a FIG. 5 is an example of the relationship between the preamble signal head position and Θ with respect to FFT input range

Z

Is a diagram illustrating a.

FIG. 6 is a diagram showing an example of a structure of a receiver of the fourth embodiment.

[7] FIG. 7 is a diagram showing an example of a structure of a receiver of the fifth embodiment.

[8] FIG. 8 is a diagram showing a configuration example of a carrier detection timing judgment unit of the sixth embodiment

[9] FIG. 9 is a diagram showing another configuration example of a carrier detection timing judgment unit of the sixth embodiment.

DESCRIPTION OF SYMBOLS

1 transmitter

2 transmission line

3,3b, 3c receiver

10 Submit information

11 modulation unit

12 IFFT 咅

13 digital Z-analog converter (DZA)

14 transmission signal

30 received information

31 demodulator

32 FFT 咅

33 analog Z-digital converter (AZD)

34 received signal 35 hours signal averaging unit

36 frequency information averaging section

40 The preamble generator

50, 50a, 50d, 50e carrier detection timing judgment unit

51 preamble pattern generator

52 complex conjugate unit

53 complex multiplier

54 Total b ^

55 absolute value calculator

56 Carrier detection determining unit

57 phase calculation unit

58 timing determination unit

59 hours averaging unit

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, the theory is bright in detail with reference to the embodiment of the signal detection apparatus according to the present invention with reference to the accompanying drawings. It should be understood that the invention is not limited by these embodiments.

[0015] Embodiment 1.

Figure 1 is a diagram illustrating an exemplary configuration of a communication apparatus (transmitter) for transmitting data to a communication apparatus provided with a signal detection apparatus according to the present invention the OFDM modulation to, 1 indicates the transmitter. The transmitter 1 receives transmission information 10 becomes bit column force, a modulation unit 11 for outputting the modulation results, the IFFT unit 12 for converting the frequency domain power also to the time domain the output of the modulation unit 11, I FFT the output of section 12 digital Z-analog converter for converting into analog form and (D / a) 13, a known signal for carrier detection and timing determination (hereinafter, preamble and hump) when generating its original It includes a preamble generator 40 which generates a preamble pattern to be a. Incidentally, 14 is a transmission signal to analog converter, 2 is a transmission line.

[0016] Further, FIG. 2 is a diagram illustrating a configuration example of a first embodiment of a communication apparatus having a signal detection apparatus according to the present invention (the receiver), 3 indicates the receiver. The receiver 3 converts the received signal 34 from the transmission side analog Z-digital converter (A / D) 33 which converts the digital format, the output of the A ZD conversion unit 33 into the time domain mosquito ゝ Luo frequency domain an FFT unit 32, the FFT unit 3 2 of the output demodulates bit string force is also a demodulating unit 31 for generating reception information 30 of the carrier detection timing judgment unit which performs carrier detection and timing detection based on the output of the FFT unit 32 It includes a 50, a. The two are the same transmission path as that shown in FIG. 1, the transmitter 1 and the receiver 3 forming the communication system exchanges signals via the transmission line 2.

[0017] Subsequently, the detailed operation of the transmitter 1 and the receiver 3 of the structure described above. Here, the transmitter 1 generates a transmission signal based on transmission information 10 is received by the receiver 3 to the generated signal, to recover the (transmission information 10 to generate a received signal 30 by performing the demodulation ) for explaining the operation.

[0018] First, the transmitter 1 includes a transmission of the preamble signal, it will be described with reference signal transmission operation in FIG. When transmitting a preamble signal, the preamble generation unit 40 generates a known preamble pattern determined in advance. This preamble pattern is as called M-sequence For example the other is a pseudo random pattern comprising a bit string of '0' and '1'. The generated preamble pattern is input to the modulator 11, modulator 11, for example, BPSK (Binary Phase Shift Keying) or QPSK (Quadrate Phase Shift Keying), according to a modulation scheme, such as Q AM (Quadrate Amplitude Modulation) divides the Apulian emissions Bull pattern input (bit string) for each subcarrier, it mapped to more complex plane. For example, if you shall BPSK modulating the preamble patterns, divides the bit string input also preamble generator 40 force by Lbit, if '0' "- l + 0j", if "1" "1 + Oj and so ", and converts the complex data representing the two points on the complex plane.

[0019] complex data generated by the modulation unit 11 is input to the I FFT unit 12 as the information in the frequency domain for each subcarrier. IFFT unit 12 converts the information entered into the time domain information, and outputs the digital time waveform information equal to the composite wave obtained by combining the waveform of each sub-carrier. Furthermore, digital time waveform information, digital Z-analog converter by (hereinafter, DZA called a converting unit) 13 is converted into a signal in analog form, issued sent to the transmission path 2 as the transmission signal 14.

[0020] In addition, the preamble pattern be assigned to all subcarriers, good be allocated a portion of Sabukiyari Anomi Te use ヽ. [0021] Furthermore, when transmitting the transmission information 10, the point at which any transmission information bit sequence in place of the known patterns inputted to the modulator 11 is input from the preamble generator 40 (transmission information 10) only different, the basic operation of the modulation unit 11, IFFT unit 12 and the DZA converter 13 is similar to the operation of the preamble signal transmission as described above. However, the modulation method of the transmission information but it may also use the same necessary Nag other modulation scheme is a modulation scheme of the preamble.

[0022] Note that the method of realizing the preamble generator 40, a method of generating a preamble pattern using a shift register and XOR operation circuit if pseudo random sequence such as M sequence, because Ji roughness force as a memory preamble and a method allowed to store the pattern. Also, when the preamble generator 40 and the memory configuration, may be stored the digital time between waveform information of the preamble signal. In this case, the output of the preamble generator 40 is input directly to the DZA converter 13.

[0023] Next, the receiver 3 will be described operation when a signal is received (received signal 34) via the transmission path 2. When receiving data in, when there is an input of the received signal 34, analog-Z-digital converter (hereinafter, referred to as AZD conversion unit) 33 converts it into digital time waveform information. FFT unit 32 that corresponds to the signal conversion means, by converting the input from AZD converter 33 into frequency domain to generate a complex data as a frequency-domain information for each subcarrier. Demodulation unit 31, for example, BPSK, QPSK, in accordance with the predetermined et demodulation scheme such as QAM, the input from AZD converter 33, and de-maps the bit string for each sub-carrier, as a continuous bit string to generate the received information 30.

[0024] Tsu to the reception processing of the preamble signal, also, FFT unit 32, until the operation for converting into time domain force frequency domain AZD converter 33 input is the same as reception processing of the data. At the time of the preamble signal reception, the complex data of each subcarrier generated by the FFT unit 32 is inputted to the carrier detection timing judgment unit 50, the carrier detection timing-format tough 50 performs detection and timing determination carrier.

[0025] Subsequently, the operation of carrier detection timing detection unit 50. Figure 3 is a diagram illustrating a configuration example of a carrier detection timing determination unit 50 included in the receiver of the present embodiment. The carrier detection timing detection unit 50 converts a preamplifier Le pattern generation unit 51 that generates frequency information for each subcarrier of the same known signal shall be transmitted (a preamble signal) from the transmitter 1, the complex the complex conjugate value a complex conjugate unit 52 which, with the complex multipliers 53, the complex summer 54 to calculate the sum of the plurality of complex numbers, the absolute value calculator 55 for leaving calculate the absolute value of a complex number, the absolute of the calculated complex number compared with predetermined threshold values ​​comprises an absolute value and Canon rear detection determining unit 56 determines that the carrier is detected in the case of more than the threshold value, the.

[0026] complex number information for each subcarrier inputted from the FFT unit 32 to the carrier detection timing detection unit 50 and X (i is the subcarrier number). In carrier detection timing detection unit 50, a preamble pattern generator 51 corresponding to the known frequency information generating means (the i subcarrier number) complex information P for each subcarrier in the preamble signal to generate them complex conjugate generator complex conjugate unit 52 which corresponds to means for converting the complex conjugate P *. Then, complex multiplier 53, which corresponds to the multiplication means to obtain a Y by multiplying the complex number information X of the received signal the P *. In addition, the complex summator 54 which corresponds to the adding means for calculating the sum Z of Y. Thus obtained Z can be expressed by the following equation (1).

[0027] [number 1]

i = 0 i = 0

••• (1)

[0028] Then, the absolute value calculator 55 calculates the absolute value of the sum value Z complex summer 54 output. Z is also a complex number, if it was a "Z = A + Bj", the absolute value of which is represented by the following formula (2).

[0029] [number 2]

^{| Z | = VA 2 + B} 2

••• (2)

[0030] Further, instead of the absolute values ​​shown in the above equation (2) (corresponds to the amplitude), the absolute value calculating the square value (corresponding to power) of the total sum value Z as shown in the following equation (3) the like parts 55 is calculated, the carrier detection-format tough 56 may perform a carrier detection using the square value of the sum Z. ^{Z 2 = A 2 + B 2} - - (3)

[0031] A sum value of all the _subcarriers; use a (multiplication result Y obtained by adding all) V, Runode the Tsu only some of the subcarriers Nag, the sum of the hand (the multiplication result _Y; it may be to calculate the added values) for that selected part to execute the subsequent processing using the addition result from the. The absolute value calculating section 55 and the carrier detection unit 56 constitutes a signal detecting hand stage.

[0032] Here, the above equation (2) or (3) capable of carrier detection reasons using is described. By multiplying the complex conjugate P complex information X and a preamble pattern of the received signal *, it multiplied if the received signal is a preamble signal results Y, how subcarriers also "iota + Oj" becomes, the total sum value " k + Oj ", the absolute value of the sum value is k. On the other hand, if the received signal is different from the preamble signal signal _Y; becomes a different value for each sub-carrier, the absolute value of the total sum value becomes smaller than k. If using a pseudo-random pattern, such as M-sequence as a preamble pattern, the more the number of subcarriers is large, the absolute value of the sum values ​​in the case of receiving the non-preamble signal approaches 0 (zero).

[0033] In the real environment for performing communication, even when receiving the preamble signal for amplitude and phase changes due to channel characteristics, although not necessarily the absolute value is k, the multiple sub by taking the sum of the carrier, and when receiving the preamble signal, it will produce a clear difference in the absolute value in the case of receiving the other signal. Therefore, Kiyari § detection determining unit 56, the absolute value, it is possible to determine that carrier detection when the threshold is exceeded for signal detection determining predetermined in consideration of channel characteristics, It can detect the timing at which preamble signals are present. Where a preamble pattern you BPSK modulation has been described as an example, but the same applies when using other modulation schemes.

[0034] signal detection determination threshold, the absolute value and the absolute value of the based! /, Te decision on the relationship of the sum value when receiving a non-preamble signals of the summation values ​​in the case of receiving the preamble signal to. For example, the bit pattern to be used as a preamble pattern, the compared time carrier detection determination (LV, "absolute value" of the sum value as a target to be compared with the value, whether to use "square value of the absolute value"), type of information to be added when calculating the sum (what process the information obtained by Do to Caro calculated with respect to the input X to Kiyari § detection timing judgment unit), when calculating the sum the addition target number (number of information to be added), is determined in consideration of. Incidentally, from among a plurality of thresholds had been determined in advance in consideration of the channel characteristics, also good V ヽ as selected and used as appropriate optimal threshold value depending on the channel characteristics, Choi previously determined by per cent ヽ Tashiki ヽ values ​​in the so that use with appropriately adjusted according to the channel characteristics.

[0035] Thus, in this embodiment, the sender, to a plurality of frequencies determined because Ji roughness force, transmits those assigned a rough mosquitoes ゝ Ji because defined preamble pattern respectively as a preamble signal. On the other hand, on the receiving side, the preamble signal reception also separates the information for each frequency using FFT as in the case of data demodulation, using the results obtained by multiplying them with double prime conjugate value of the preamble patterns respectively Te, and to perform carrier detection and timing determined by determining the similarity between the received preamble signal and flop Lian Bull pattern. Thus, as compared with the case of performing carrier detection, etc. using only power that has been used conventionally, it is possible to reduce the possibility of performing erroneous detection.

[0036] Further, the FFT unit 32 Ya complex multiplier 53, so typical OFDM receiver is a circuit that includes normal for data reception, the demodulation of carrier detection and data do not need to perform simultaneously, it is possible to use the same circuit to detect a carrier. That is, it is possible as compared to the carrier detection by the correlation between the conventional time region, to realize a receiver as described above with a small circuit scale.

[0037] Embodiment 2.

Subsequently, a description will be given signal detection apparatus of the second embodiment. In the first embodiment described above, Oite the FFT result is obtained to perform the determination of the carrier detection by using the sum of complex multiplication results forces the embodiment of the conjugate complex value of a preamble pattern of the received signal the complex multiplication result of the complex conjugate values ​​of the preamble pattern further 2 Tsunosa subcarrier between using the result of the conjugate complex multiplication, determined in a minute unit than the time interval inputted preamble signal reception timing in the FFT a case will be described in which.

[0038] The transmitter of the present embodiment has the same configuration as the transmitter of the first embodiment described above (see Figure 1). The receiver is the same configuration as the receiver of the first embodiment (see FIG. 2), different detailed structure of the carrier detection timing judgment unit part. Therefore, in the present embodiment, portions other than the carrier detection timing judgment unit, the description is omitted, the operation of the timing detection determining unit (a timing detection determining unit 50a in this embodiment) only Description I do.

[0039] FIG. 4 is a diagram illustrating a configuration example of a carrier detection timing determination unit 50a of the second embodiment. The carrier detection timing judgment unit 50a, to the carrier detection timing-format tough 50 of the first embodiment, further downstream of the complex multiplier 53 (the second) (the second) complex conjugate 52 and the complex multiplier vessel is added, also, a configuration of the phase calculating unit 57 and the timing determination unit 58 is additionally Caro. Note that, the other parts, and a description thereof will be omitted given the same reference numerals and the carrier detection timing judgment unit 50.

[0040] In the carrier detection timing determination unit 50a configured as described above, subsequent complex conjugate 52, except Y of the preceding complex multiplier 53 output (i.e. Y, Y, · · ·, Y) of the complex conjugate ( k 1 2 k-1

Y *, Y *, to conversion and ..., to Y *). Subsequent complex multiplier 53, exits the rear stage of the complex conjugator 52

1 2 k-1

Force (Y *, Y *, · ··, Y *) preceding other than Y of the complex multiplier 53 output (i.e. Y, Y, · · ·,

1 2 k-1 1 2 3

Y) is multiplied by each. The complex summer 54, the sum value Z k of the subsequent complex multiplier 53 outputs

It is calculated. Here, the complex multiplier 53 outputs a subsequent and Y ', the sum value Z, the following equation (

i- (il)

It can be represented by 4).

[0041] [Equation 3] z = ΣY '-. (Ii) = Σ Y = Σ (x) · (Xi-i · Pi- i = li = li = l Γ) *

•••(Four)

[0042] Here, a description Te reason Nitsu ヽ added a later stage of the complex conjugator 52 and the rear stage of the complex multiplier 53. If the input range when inputting the received preamble signal to the FFT unit 32 does not match the output range at the time of generation of the transmit side, the complex conjugate value P * of the multiplication result of complex information X and flop Lian Bull pattern of the preamble signal Y produces a phase rotation corresponding to the shift amount and frequency of each subcarrier of the input range of the FFT unit 32 outputs the range and at the time of reception when the IFFT unit 12 as viewed as a vector. As a result, when it is complex adding the respective Y, components cancel each other by the phase difference in occurs. Therefore, obtained by further complex multiplication of Y with respect to the complex conjugate of the neighboring Sabukiyari § Y * Y 'is the subcarrier

i-1 i iG-1) becomes a vector having a phase rotation amount corresponding to the interval frequency, if there is one Jode subcarrier spacing frequency and vector (complex information) between any sub-carrier having the same phase.

The output of [0043] the complex summer 54 is input to an absolute value calculator 55 and the phase calculation unit 57. Processing in the absolute value calculating section 55 and the carrier detection judging section 56 is the same as the first embodiment described above. However, the threshold value of the signal detection judging the carrier detection judging section 56 is used is different from that used in the first embodiment. That is, the carrier detection judging unit 5 6, for example, information of type (complex conjugate combination 52 and complex multiplier 53 complex summer 54 adds when calculating the total sum value to the input X of the carrier detection timing judgment unit taking into account the one) is added to information obtained by executing processing such as etc. up vs. use those obtained by deformation of the threshold using Te embodiment 1 smell embodiment.

[0044] In the first embodiment, the carrier detection judgment 56, the input value (output of the absolute value calculating section 55) had a detection timing of the preamble signal when the threshold is exceeded. However Na husk, time waveform input to the FFT unit 32 has a width of the time intervals corresponding to the input range of the FFT unit 32, the timing information over the time interval can not be obtained (impossible to increase the detection accuracy) . Therefore, in the present embodiment, because that obtain a more detailed timing, phase calculator 57 first is to determine the phase of the sum Z by using the following equation (5).

[0045] [Expression ^{4] tan _1 (B / A} ) (if Α> 0)

tan one ^{1 (Β / Α) + π} ( field A <0 & B≥0)

^{ί3η _1 (Β / Α) -} π (if A <0 & B <0)

•••(Five)

Further, FIG. 5, one relationship preamble signal head position and 0 for FFT input range

Z

Is a diagram illustrating an example. As described above, if the input range of the FFT unit 32 upon receiving the output range of the IFFT unit 12 in the preamble signal generated does not match, Y input range of the FFT unit 32

i- (il)

It becomes generated phase rotation corresponding to the displacement amount and the subcarrier spacing frequency of circumference. Therefore, the timing determination unit 58, using the following equation (6) calculates the shift amount ΔΤ head position of the received signal input ranges and preamble to the current FFT unit 32, reception timing using ΔΤ

FFT FFT

The judges. Where T is the time corresponding to the input range of the FFT unit 32. Incidentally, _c the phase calculation unit 57 and the timing determination unit 58 constitute a timing decision unit Equation 5

(Field _θ ζ> 0)

2π

^ ^ FFT

FFT

^{1 FFT + ^ 7 X (θ} ζ <0)

2π

••• (6)

[0048] By adjusting the reception timing based on the .DELTA..tau, receiver, more accurate

FFT

It is possible to demodulate the data at the timing.

[0049] In this embodiment, Y between adjacent subcarriers may be obtained 'seek, Y between its so that there use the sum force any subcarriers'. Or it may be used only some of the subcarriers. However, Y 'when asked Mel the can, Y according to the frequency spacing between the subcarriers' between any sub-carrier also force the phase of a value corresponding to the phase rotation in the frequency interval between 1 subcarriers compensation is needed, such as calculating the sum Zeta.

[0050] Thus, in this embodiment, the sender, to a plurality of frequencies determined because Ji roughness force, transmits those assigned a rough mosquitoes ゝ Ji because defined preamble pattern respectively as a preamble signal. On the other hand, on the receiving side, the preamble signal reception also separates the information for each frequency using FFT as in the case of data demodulation, using the results obtained by multiplying them with double prime conjugate value of the preamble patterns respectively Te, and to perform carrier detection and timing determined by determining the similarity between the received preamble signal and flop Lian Bull pattern. Thus, as compared with the case of performing carrier detection, etc. using only power that has been used conventionally, it is possible to reduce the possibility of performing erroneous detection.

[0051] Further, the FFT unit 32 Ya complex multiplier 53, so typical OFDM receiver is a circuit that includes normal for data reception, the demodulation of carrier detection and data do not need to perform simultaneously, it is possible to use the same circuit to detect a carrier. That is, it is possible as compared to the carrier detection by the correlation between the conventional time region, to realize a receiver as described above with a small circuit scale.

[0052] Further, paying attention to the phase rotation of the FFT output when the input range of the FFT unit 32 output range at the time of reception of the preamble signal generation when the IFFT unit 12 do not match, position phase deviation force FFT section between subcarriers at any timing within the time of the input range of the 32 it is possible to know whether it has received the beginning of the preamplifier Le signal.

[0053] Embodiment 3.

Subsequently, a description will be given signal detection apparatus of the third embodiment. Above embodiment, Do repetition of, although those described for the case of using a preamplifier Le signal generated from a known preamble pattern determined in advance, in the present embodiment, a continuous plurality of times preamble pattern It described carrier detection and timing determination when using Briar tumble signal generated based on what was repeated.

[0054] The transmitter of the present embodiment, taking the same configuration as the transmitter of the first embodiment described above (see Fig. 1), the only difference generation operation of the preamble signal in the first embodiment. Also, the receiver takes the same configuration as the receiver of the first embodiment (see FIG. 2), different only carrier determination operation in the first embodiment. Incidentally, the configuration of the carrier detection timing judgment unit that the receiver comprises may be similar to that of the second embodiment. The operation of the transmitter and receiver will be described focusing on differences from the first exemplary embodiment.

[0055] The transmitter, the transmission operation of the preamble signal, the same preamble pattern generates a repetitive signal continuously multiple times, the point to be transmitted is different from the transmitter of the first embodiment of this as a preamble signal. It is to be noted that the number of repetitions of the preamble pattern and L times. Other operations are the same as in the first embodiment.

[0056] On the other hand, in the receiver, the carrier detection determining unit 56, by successive FFT processing result of one alone to determine immediately the carrier detection when the threshold is exceeded the nag M times (M≤L) of Z absolute value of (output of the complex summer 54) (or square value of the absolute value), it is determined that the carrier detection when exceeded N times (N≤ M) threshold.

[0057] The configuration of the carrier detection timing judgment unit the receiver provided in the case of the same as in the receiver shown in the second embodiment, the timing determination unit 58, Chi caries M consecutive FFT processing result, the average of Z phase Θ when the carrier detection determining unit 56 has exceeded a threshold

Z

Determine the value. When the carrier detection determining unit 56 determines that the carrier detection, theta

Z

Calculating a ΔΤ using the average value to determine the reception timing. Or the timing-format tough 58 of Z when the carrier detection determining unit 56 has exceeded a threshold phase Θ

Z

Seeking .DELTA..tau from further obtains the average value of .DELTA..tau. Then, the carrier detection judging section 56

FFT FFT

Determining reception timing but when it is determined that the carrier detection, using the average value of ΔΤ

FFT

Choi so as to.

[0058] Thus, in this embodiment, the sender, to a plurality of frequencies determined because Ji rough force, use a continuous transmission multiple times by assigning predetermined preamble pattern respectively as a preamble signal to. On the other hand, on the receiving side, the preamble signal received also separates the information for each frequency using an FFT similar to the demodulation of the data, using the results obtained by multiplying them with the complex conjugate of the preamble pattern Te, and to perform carrier detection and timing determined by determining a plurality of times similarity between the received preamble signal and preamble patterns. Accordingly, and when performing wire carrier rear detection only power that has been used conventionally, as compared with the case where carrier detection or the like based on the only the determination result once shown in Embodiment 1, the second embodiment, erroneous as possible out to reduce the possibility of detecting.

[0059] Further, the FFT unit 32 Ya complex multiplier 53, so typical OFDM receiver is a circuit that includes normal for data reception, the demodulation of carrier detection and data do not need to perform simultaneously, it is possible to use the same circuit to detect a carrier. That is, it is possible as compared to the carrier detection by the correlation between the conventional time region, to realize a receiver as described above with a small circuit scale.

[0060] Furthermore, in the case structure of the carrier detection timing determination unit 50 is configured as shown in FIG. 4 (if the configuration of a receiver similar to the receiver Embodiment 2), IF FT of the preamble signal generating input range of the output range and the reception time of the FFT portion 32 of the part 12 is focused on the phase rotation FFT output of Otherwise, any timing in the time of the input range of the phase deviation force FFT portion 32 between subcarriers it is possible to know whether it has received the beginning of the preamble signal in.

[0061] Embodiment 4.

Subsequently, a description will be given signal detection apparatus of the fourth embodiment. In the third embodiment described above, but a preamble signal transmitter transmits has been described with the carrier detection and timing determination when it is generated based on a repeat multiple times in succession a preamble pattern, the present embodiment in averages the received time waveform, the case of determining the carrier detect therewith.

[0062] The transmitter of the present embodiment, taking the same configuration as the transmitter of the first embodiment described above differ only generation operations of the preamble signal in the first embodiment. The transmitter, you!, The transmission operation of the preamplifier Le signal Te, the same preamble pattern generates a plurality of times continuously repeating signal, which transmitter of the first point to be transmitted is implemented as a preamble signal different. It is to be noted that the number of repetitions of the preamble pattern and L times. Other operations are the same as in the first embodiment.

[0063] FIG. 6 is a diagram showing an example of a structure of a receiver of the fourth embodiment. Receiver of the present embodiment takes a configuration in which the time signal averaging unit 35 to the receiver of the first embodiment described above is added. Since the other portions are the same as the receiver according to the first embodiment, description thereof will be omitted given the same reference numerals. This will hereinafter be described receiver of the present embodiment and the receiver 3b.

[0064] To explain the operation of the receiver 3b with reference to FIG. First, when receiving the data, the receiver 3b performs the same operation as the receiver 3 of the first embodiment. That is, when there is the input of the received signal 34, AZD converter 33 converts it to a digital time waveform information, and inputs the received signal after conversion to the FFT unit 32. The subsequent operation is the same as the operation shown Te you! / ヽ to the first embodiment.

[0065] Next, receiving a preamble signal, when performing a carrier detection and timing determination, the time signal averaging unit 35, each input range minute of time of the FFT unit 32 the output of AZD converter 33 parts once immediately before the (1≤L) minute time waveform averaging, and outputs the AZD converter 33 parts output after averaging with respect to the FFT unit 32.

[0066] Contact time t, Te of AZD input range fraction of the FFT unit 32 obtained from the conversion section 33 time T

FFT

If minute digital time waveform information expressed by the following equation (7) as S (t), the output S from the time signal averaging unit 35 at time t (t) is be represented by the following formula (8) it can.

avr

[0067] [6]

_{S (t) = {s 0} (t), S l (t), s 2 (t), - - -, s TFFT (t)} • (7)

[0068] [Equation 7]

••• (8)

[0069] FFT unit 32, the frequency domain information averaged time waveform S (t) represented by the above formula (8)

avr

Converted to, and output the carrier detection timing judgment unit 50. The subsequent operation is the same operation as that shown in the first embodiment.

[0070] Incidentally, you!, Te in this embodiment has been described as a configuration obtained by adding a time signal averaging unit 35 to the receiver of the first embodiment is not limited thereto, exemplary it may be configured to add a time signal averaging unit 35 with respect to the embodiment 2 receiver. Further, in the detection and timing determination carrier, as described in the third embodiment, based on the plurality of determine the constant results, be performed carrier detection, and the like Te Yo,.

[0071] Thus, in this embodiment, the sender, to a plurality of frequencies determined because Ji rough force, use a continuous transmission multiple times by assigning predetermined preamble pattern respectively as a preamble signal to. On the other hand, on the receiving side, if the preamble signal reception, after averaging the received time waveform, separates the information for each frequency using FFT as in the case of data demodulation, and the complex conjugate value thereof preamble pattern using the results obtained by multiplying respectively, to perform the carrier sensing and timing determined by determining the similarity between the received preamble signal and preamble patterns. This ensures, or when performing carrier detection only power that has been conventionally used, indicated in the embodiment described above, as compared with the case of performing carrier detection, etc., without averaging the time waveform, the false detection it is possible to reduce the possibility of performing.

[0072] Further, the FFT unit 32 Ya complex multiplier 53, so typical OFDM receiver is a circuit that includes normal for data reception, the demodulation of carrier detection and data do not need to perform simultaneously, it is possible to use the same circuit to detect a carrier. That is, it is possible as compared to the carrier detection by the correlation between the conventional time region, to realize a receiver as described above with a small circuit scale.

[0073] Furthermore, in the case structure of the carrier detection timing determination unit 50 is configured as shown in FIG. 4 (if the configuration of a receiver similar to the receiver Embodiment 2), IF FT of the preamble signal generating input range of the output range and the reception time of the FFT portion 32 of the part 12 is focused on the phase rotation FFT output of Otherwise, any timing in the time of the input range of the phase deviation force FFT portion 32 between subcarriers it is possible to know whether it has received the beginning of the preamble signal in.

[0074] Embodiment 5.

Subsequently, a description will be given signal detection apparatus of the fifth embodiment. In Embodiment 4 described above, although the received time waveform had to perform the determination of the averaged carrier detection, in this embodiment, to average the frequency information after the FFT processing by using the key It will be described for determining the Yaria detection.

[0075] The transmitter of the present embodiment, taking the same configuration as the transmitter of the first embodiment described above differ only generation operations of the preamble signal in the first embodiment. The transmitter, you!, The transmission operation of the preamplifier Le signal Te, the same preamble pattern generates a plurality of times continuously repeating signal, which transmitter of the first point to be transmitted is implemented as a preamble signal different. It is to be noted that the number of repetitions of the preamble pattern and L times. Other operations are the same as in the first embodiment.

[0076] FIG. 7 is a diagram showing an example of a structure of a receiver of the fifth embodiment. Receiver of the present embodiment has a configuration in which frequency information averaging unit 36 ​​is added to the receiver of the first embodiment described above. Since the other portions are the same as the receiver according to the first embodiment, the description of those same reference numerals will be omitted. This will hereinafter be described receiver of the present embodiment and the receiver 3c.

[0077] To explain the operation of the receiver 3c with reference to FIG. First, when receiving the data, the receiver 3c performs the same operation as the receiver 3 of the first embodiment.

[0078] Next, receiving a preamble signal, when performing a carrier detection and timing determination, complex data of each subcarrier is output from the FFT unit 32 is input to the frequency information averaging portion 36. Frequency information averaging portion 36, once immediately before each frequency band of the output range component of the FFT unit 32 (1≤L) in the frequency information (complex data) averaging, frequency information after averaging carrier detection and it outputs the timing determination unit 50.

[0079] frequency band F of the output range component of the FFT unit 32 obtained from the FFT unit 32 at time t min

FFT

If the frequency information expressed as D (t) as in the following equation (9), the output D of the FFT portion 32 or et at time t (t) can be expressed by the following equation (10).

avr

[0080] [number 8]

_{D (t) - (d 0} (t), d, (t), d 2 (t), -, d FFFi (t)

••• (9)

[0081] [number 9]

1-1 1 1-1 1-1

_{Xd 0 (t-iF FFT)} - iF FFr) J d 2 (t-iF FFT) Σα Ρρρτ (t-iF FFT) i-0 i = 0 i-0 i = 0

D _avr (t):

••• do)

[0082] Carrier detection timing judgment unit 50 performs carrier detection and timing determined based on the averaged frequency information represented by the above formula (10) D (t). The carrier detection dynamic avr

Create and timing determination operation is the same as that you showed Te in the first embodiment.

[0083] In the present embodiment has been described as a configuration obtained by adding the frequency information averaging unit 36 ​​to the receiver of the first embodiment is not limited thereto, the reception of the second embodiment it may be configured to add the frequency information averaging unit 36 ​​with respect to the machine. Further, Yo in performing carrier detection and timing determination, as described in the third embodiment, based on a plurality of determination results, be performed carrier detection like Te.

[0084] Thus, in this embodiment, the sender, to a plurality of frequencies determined because Ji rough force, use a continuous transmission multiple times by assigning predetermined preamble pattern respectively as a preamble signal to. On the other hand, on the receiving side, if the preamble signal received, it separates the information for each frequency using FFT, further information after the separation respectively averaging the complex conjugate of the preamble pattern information after averaging and multiplication, respectively using the results obtained by, and to perform carrier detection and timing determined by determining the class similarity between the received preamble signal and preamble patterns. More thereto, and when performing carrier detection only power that has been conventionally used, indicated in the embodiment described above, as compared with the case of performing carrier detection, etc., without averaging the frequency information, the false detection it is possible to reduce the possibility of performing.

[0085] Further, the FFT unit 32 Ya complex multiplier 53, so typical OFDM receiver is a circuit that includes normal for data reception, the demodulation of carrier detection and data do not need to perform simultaneously, it is possible to use the same circuit to detect a carrier. That is, it is possible as compared to the carrier detection by the correlation between the conventional time region, to realize a receiver as described above with a small circuit scale.

[0086] Furthermore, in the case structure of the carrier detection timing determination unit 50 is configured as shown in FIG. 4 (if the configuration of a receiver similar to the receiver Embodiment 2), IF FT of the preamble signal generating input range of the output range and the reception time of the FFT portion 32 of the part 12 is focused on the phase rotation FFT output of Otherwise, any timing in the time of the input range of the phase deviation force FFT portion 32 between subcarriers it is possible to know whether it has received the beginning of the preamble signal in.

[0087] Embodiment 6.

Subsequently, a description will be given signal detection apparatus of the sixth embodiment. In the fourth and fifth embodiments described above, respectively, in the averaging to form the To have force present as a determination of carrier detection frequency information after the received time waveform and FFT is just before the carrier detection and the information just before timing determination averaged, the case of performing Kiyari § detection and timing determination therewith.

[0088] The transmitter of the present embodiment, taking the same configuration as the transmitter of the first embodiment described above differ only generation operations of the preamble signal in the first embodiment. The transmitter, you!, The transmission operation of the preamplifier Le signal Te, the same preamble pattern generates a plurality of times continuously repeating signal, which transmitter of the first point to be transmitted is implemented as a preamble signal different. It is to be noted that the number of repetitions of the preamble pattern and L times. Other operations are the same as in the first embodiment.

[0089] The configuration of the receiver is similar to the receiver according to the first embodiment, different detailed configuration of the carrier detection timing judgment unit part. Therefore, in the present embodiment, portions other than the carrier detection timing judgment unit, the description is omitted, a description only the operation of the timing detection-size tough.

[0090] FIG. 8 is a diagram illustrating a configuration example of a carrier detection timing judgment unit of the sixth embodiment, the carrier detection timing judgment unit 50 according to Embodiment 1 of implementation (see FIG. 3), the carrier it is obtained by adding a time-averaging unit 59 for averaging the information immediately before the discovery. Note that in the explanation of operation will be described later, it describes a carrier detection timing judgment unit of this configuration the carrier detection timing judgment unit 50d. Further, portions other than the time averaging unit 59, the description thereof is omitted the same reference numerals and the carrier detection timing judgment unit 50.

[0091] Further, FIG. 9 is a diagram showing another configuration example of the carrier detection timing judgment unit of the sixth embodiment, with respect to the carrier detection timing judgment unit 50a according to the second embodiment (see FIG. 4) Te is obtained by adding a time averaging unit 59 for averaging the information immediately before the carrier detection. Note that in the explanation of operation will be described later, it describes a carrier detection timing judgment unit of this configuration the carrier detection timing judgment unit 50e. Also, For the parts other than the time averaging unit 59, you not be described are denoted by the same reference numerals and the carrier detection timing judgment unit 50.

[0092] Carrier detection timing judgment unit 50d, and 50e, contact the deviation, even, time-averaging unit 59 which corresponds to the sum averaging unit, once the output of the complex summer 54 just before (1≤L ) partial frequency information by averaging the output. Incidentally, the summation value obtained at time t and Z (t), the input range fraction of the time of the FFT unit 32 when T, the from the time averaging unit 59 at time t

FFT

Information output Z (t) can be expressed by the following equation (11).

avr

[0093] [number 10]

_{Z avr (t Z (t -} iT FFT)

i = 0

••• (11)

[0094] In any of the carrier detection timing judgment unit 50d, and 50e also the absolute value calculating unit 5 5 and the phase calculation unit 57 based on the output from the time averaging unit 59, shown in the first or second embodiment described above processing the execution was. The carrier detection unit 56, timing determination section 58, contact each output from the absolute value calculating section 55, Te based! /, The output from the phase calculating unit 57, to the first or second embodiment described above executes the process shown Te.

[0095] In the present embodiment, not limited to this force and adding the time-averaging unit 59 with respect to the carrier detection timing judgment unit included in the receiver the first or second embodiment, the embodiment Yo ヽ be additionally time averaging unit 59 with respect to the carrier detection timing judgment unit which performs the operation described in embodiment 3.

[0096] Thus, in this embodiment, the sender, to a plurality of frequencies determined because Ji rough force, use a continuous transmission multiple times by assigning predetermined preamble pattern respectively as a preamble signal to. On the other hand, on the receiving side, if the preamble signal receiving, the information used in performing carrier detection and timing detected time-averaged, and to perform carrier detection and timing determined using the results. This Ri by the, or when performing carrier detection only power that has been conventionally used, as shown at the embodiment described above, carrier information used in performing carrier detection and timing detection without averaging compared to the case of detecting the like, it is possible to reduce the possibility of performing erroneous detection.

[0097] Further, the FFT unit 32 Ya complex multiplier 53, so typical OFDM receiver is a circuit that includes normal for data reception, the demodulation of carrier detection and data do not need to perform simultaneously, it is possible to use the same circuit to detect a carrier. That is, it is possible as compared to the carrier detection by the correlation between the conventional time region, to realize a receiver as described above with a small circuit scale.

[0098] Furthermore, in the receiver with carrier detection timing judgment unit 50e, the phase rotation of the FFT output if the input range of the FFT unit 32 upon receiving the output range of the IFFT unit 12 in the preamble signal generated does not match focusing on, it is possible to know the mosquitoes ゝ that has received the beginning of the preamble signal at any timing within the time of the input range of the phase deviation force even FFT portion 32 between the sub-carrier.

Industrial Applicability

[0099] As described above, the force Cal signal detection apparatus in the present invention are useful in communications systems, in particular, on the basis of a known signal, a communication apparatus for detecting with high precision with a small circuit scale of the desired signal and the symbol timing It is suitable for the receiver is provided.

Claims

The scope of the claims

[1] A signal detection device for detecting the modulated desired signal OFDM (Orthogonal Frequency Division Multiplexing) scheme from the received signal,

A signal conversion means for converting the received signal into a frequency domain information for each carrier (the first frequency-domain signal),

It is known that certain known information contains and frequency and the initial phase are different, signals of a plurality of carriers based on multiplexed signal Te, and generates the frequency area information of each carrier (the second frequency-domain information) and the frequency information generating means,

Complex conjugate generation means for generating the complex conjugate of the second frequency region information outputted from said known frequency information generating means for each carrier,

A first frequency-domain signal for each of the carrier, the complex conjugate every carrier generated by the complex conjugate generation means, and multiplying means for multiplying at the same frequency domain between a portion of the multiplication output by said multiplication means or adding means for adding all, the addition absolute value or calculates the square value of the addition result of the results, detection determination of the desired signal using a predetermined threshold value, which is predefined and Contact the calculation result a signal detecting means for performing,

Signal detecting apparatus comprising: a.

[2] the multiplication means,

Select two or more multiplication results from said multiplication result, and generates the complex conjugate of the selected multiplication results for each complex conjugate thus generated, the multiplication of the frequency domain separated by a predetermined distance the results are multiplied, respectively,

It said adding means, the signal detection apparatus according to 請 Motomeko 1, characterized in adding some or all of the multiplication results.

[3] In addition,

Wherein when the signal detecting means detects the desired signal, calculating a phase of the addition result, based on the obtained phase, Te timing determining means for determining the exact timing of receiving the desired signal,

Signal detection apparatus according to claim 2, characterized in that it comprises a.

[4] If a repetition of the bit string of a specific pattern of the predetermined known information,

Said signal detecting means, said desired signal detection determination processing executed multiple times within a range that does not exceed the repetition times the number of the bit string, the plurality of times of execution result final the detected force assimilate the desired signal based on signal detection apparatus according to claim 1, 2 or 3, characterized in that to determine.

[5] the signal detecting means, claims, characterized in that it is determined that the number of times of detection of the desired signal in the plurality of times of execution results when a stipulated number of times or more, to eventually detect the desired signal signal detection apparatus according to 4.

[6] In addition,

If a repetitive bit sequence of a specific pattern of said predetermined known information, the received signal in the time domain, for each section in which the bit string has been placed, the number of repetitions of the bit sequence acquired a plurality of times at exceed no range, time signal averaging means for averaging the obtained signal,

Equipped with a,

Said signal conversion means, the signal detection apparatus according to claim 1, 2 or 3, characterized in that to convert the frequency domain information output of the time signal averaging means.

[7] In addition,

If a repetitive bit sequence of a specific pattern of said predetermined known information, each output of said signal conversion means obtains Te Watatsu multiple times within a range that does not exceed the number of repetitions of the bit sequence, the output the acquired frequency information averaging means for averaging for each carrier comprises,

Said multiplying means, the signal in place of the conversion output uses an averaging output for each wire carrier rear of said frequency information averaging means, said each averaging output, the complex of each carrier generated by the complex conjugate generation means multiplying the conjugate, with the same frequency domain between the signal detection apparatus according to claim 1, 2 or 3, feature a.

[8] In addition,

If a repetitive bit sequence of a specific pattern of the predetermined known information, the addition Tokushi preparative added output of the hands-stage multiple times within a range that does not exceed the number of repetitions of the bit sequence, averaging the sum output the acquired addition result averaging means,

Equipped with a,

Said signal detecting means, said addition result was or absolute value of the averaged result of the averaging means calculates the square value of the averaged result, the calculation result and Ki above !, use values, Te of the desired signal signal detection equipment according to claim 1 or 2, characterized in that the detection decision.

[9] In addition,

If a repetitive bit sequence of a specific pattern of the predetermined known information, the addition Tokushi preparative added output of the hands-stage multiple times within a range that does not exceed the number of repetitions of the bit sequence, averaging the sum output the acquired addition result averaging means,

Equipped with a,

Said signal detecting means, said addition result was or absolute value of the averaged result of the averaging means calculates the square value of the averaged result, the calculation result and Ki above !, use values, Te of the desired signal It performs detection judgment,

It said timing determination means, wherein the calculating the averaged result of phase in the addition result averaging means, to claim 3, characterized that you determine accurate reception timing of the desired signal based on the obtained phase signal detection apparatus according.

[10] The predetermined threshold?, The value, the bit pattern to form a predetermined known information, the contents of processing said multiplication means executes, and the number of multiplications output adding means is an adder target, on the basis determining signal detection apparatus according to any one of claims 1-9, characterized in that.