JP4033967B2 - Symbol identification point detection apparatus and method, and mobile radio apparatus including the apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile radio apparatus such as a mobile phone, a simple mobile phone, and a commercial digital communication phone.
[0002]
[Prior art]
First, a conventional symbol identification point detection apparatus will be described with reference to FIGS. 21 and 2 to 5.
[0003]
FIG. 21 is a block diagram of a conventional symbol identification point detection apparatus for a mobile radio apparatus.
[0004]
In FIG. 21, an input 101 of the I-side quadrature detection result and an input 102 of the Q-side quadrature detection result of the radio unit are input to A / D converters 103 and 104, respectively.
[0005]
Based on the sampling data input from the A / D converters 103 and 104, the symbol discrimination point detection means 105 detects the symbol discrimination point.
[0006]
Next, the operation of the conventional symbol discrimination point detection apparatus configured as shown in FIG. 21 will be described.
[0007]
The I-side quadrature detection result 101 and the Q-side quadrature detection result 102 have predetermined waveforms that are continuous with respect to time t as shown in FIGS. 2 and 3, respectively. The I-side quadrature detection result 101 is input to the A / D converter 103, and the input waveform is oversampled at M times the symbol rate and converted into discrete sampling data as shown in FIG. In FIG. 4, T is a symbol interval, Ts is a sampling interval, Sn (n = 0, 1,..., M−1) is a sample at a sample position number n, and in FIG. It is.
[0008]
On the other hand, the Q-side quadrature detection result 102 is input to the A / D converter 104, and the input waveform is oversampled at M times the symbol rate and converted into discrete sampling data as shown in FIG. . In FIG. 5, T is a symbol interval, Ts is a sampling interval, Sn (n = 0, 1,..., M−1) is a sample at a sample position number n, and in FIG. It is.
[0009]
Next, L-sampling data of I-side sampling data and Q-side sampling data output from the A / D converter 103 and A / D converter 104, that is, data of L × M samples on each of the I-side and the Q-side, is obtained. The symbol identification point detection unit 105 inputs the symbol identification point, and the symbol identification point detection unit 105 detects the symbol identification point, and the sample position number of the symbol identification point, that is, the n number of Sn is obtained as symbol identification point information.
[0010]
Here, the operation of the conventional symbol discrimination point detection apparatus will be described in more detail using a specific example.
[0011]
As an example, consider symbol identification point detection when the mobile radio apparatus receives a radio format as shown in FIG. In FIG. 22, the blacked out portion is an unmodulated wave that is not modulated, and is a section used for training on the transmitting side of a base station or the like, and an arbitrary waveform with a band limited is transmitted. It is a section to be done. By the way, a symbol identification point cannot be detected with an arbitrary unmodulated wave.
[0012]
Further, in FIG. 22, the part other than the blacked-out part is a modulated wave, and is a section in which a waveform subjected to some modulation is transmitted, and the detection of the symbol identification point is the property of the modulated wave in this section. It is done using. In addition, the part enclosed by the ellipse is assumed to be the vicinity of the boundary line inside and outside the service area, the section where the received electric field level is low due to low speed fading or shadow wing, etc., and the received electric field level of other parts is sufficiently high Assume that
[0013]
In FIG. 22, the sections indicated by A, B, C, and D are the first, second, third, and third examples of the operation of the conventional symbol identification point detection apparatus described below. 4 corresponds to the example of 4 and shows a section of sampling data used for symbol identification point detection. Here, each section is not synchronized with the frame timing of the radio format. This is because the mobile radio apparatus cannot know the frame timing at the time of symbol identification point detection. A symbol identification point is detected from the sampling data for the symbol.
[0014]
First, as a first example, sampling data for ¼ of one frame time, that is, sampling data for L symbols is used for symbol identification point detection when one frame is 4L symbols. The operation of the conventional symbol discrimination point detection apparatus when symbol discrimination point detection is performed in the section indicated by A will be described.
[0015]
In the symbol identification point detection in this case, since the section where the reception electric field level of section A is sufficiently large is used and the section of the modulated wave is used, the symbol identification point detection unit 105 performs the symbol identification point detection with good performance. Done in
[0016]
Next, as a second example, sampling data for ¼ time of one frame time, that is, sampling data for L symbols is used for symbol identification point detection when one frame is 4L symbols. The operation of the conventional symbol discrimination point detection apparatus when symbol discrimination point detection is performed in the section indicated by B will be described.
[0017]
In the symbol identification point detection in this case, since the received electric field level in the section B is small, the symbol identification point detecting means 105 can operate normally even though the section B is a modulated wave. And the performance of symbol discrimination point detection deteriorates.
[0018]
Next, as a third example, sampling data for ¼ time of one frame time, that is, sampling data for L symbols is used for symbol identification point detection when one frame is 4L symbols. The operation of the conventional symbol discrimination point detection apparatus when symbol discrimination point detection is performed in the section indicated by C will be described.
[0019]
In the symbol identification point detection in this case, a section in which the reception electric field level in section C is sufficiently large is used. However, since this section C includes both modulated waves and non-modulated waves, symbol identification point detection is performed using non-modulated waves. The possibility that the means 105 operates normally is reduced, and the performance of symbol discrimination point detection is significantly degraded.
[0020]
Next, as a fourth example, sampling data for 3/4 time of one frame time, that is, sampling data for L symbols is used for symbol identification point detection when one frame is 4L / 3 symbols. The operation of the conventional symbol identification point detection apparatus when the symbol identification point detection is performed in the section indicated by 22D will be described.
[0021]
In the symbol identification point detection in this case, since the modulated wave and the non-modulated wave are mixed in the section D, the time in which the modulated wave is included in the section D is longer than the time in which the non-modulated wave is included. Regardless, in this case as well, as in the third example, the possibility of the symbol discrimination point detection means 105 operating normally by the non-modulated wave is reduced, and the performance of symbol discrimination point detection deteriorates.
[0022]
[Problems to be solved by the invention]
In the conventional symbol discrimination point detection device as described above, since the symbol discrimination point is detected only once using the sampling data for L symbols, the second example of the conventional symbol discrimination point detection device described above is used. As shown, when the received electric field level is low due to the vicinity of the boundary line inside and outside the service area, low-speed fading, shadow wing, or the like, the performance of symbol discrimination point detection deteriorates.
[0023]
Further, since symbol discrimination point detection cannot be performed for any non-modulated wave that is not modulated, symbol discrimination point detection is performed as shown in the third example of the conventional symbol discrimination point detection device. When the modulation wave and the non-modulation wave are mixed in the sampling data used in the above, the possibility that the symbol discrimination point detection unit 105 operates normally by the non-modulation wave is reduced, and the performance of the symbol discrimination point detection is Deteriorates significantly.
[0024]
Also, as shown in the fourth example of the conventional symbol discrimination point detection device, the time when the modulation wave is used for symbol discrimination point detection is longer than the time when the non-modulation wave is used However, the degradation of the performance is small compared to the third example of the conventional symbol discrimination point detection device described above, but depending on the pattern of the unmodulated wave, no matter how large L is used, only erroneous symbol discrimination point detection can be detected. It may not be possible.
[0025]
The present invention solves the above-mentioned problem, and in a system in which a modulation wave and a non-modulation wave are mixed, it is possible to detect a symbol identification point with higher performance compared to the conventional case when the reception electric field level is low. Another object of the present invention is to provide a symbol discrimination point detection apparatus that can detect symbol discrimination points with high performance.
[0026]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a symbol identification point detected from a sampling sequence for L symbols according to the prior art is set as a temporary identification point, and this is repeated N times in succession, and N number of points obtained thereby are obtained. The true symbol identification point is selected from the frequency distribution of the sample position numbers of the temporary symbol identification points. If it is difficult to select a true symbol identification point from the frequency distribution of the first sample position number, the frame timing assumed in the first consecutive N temporary symbol identification point detections The second consecutive N temporary symbol identification points are detected in the shifted time zone, and the true position is obtained from the frequency distribution of the sample position numbers of the new N temporary symbol identification points obtained thereby. Select a symbol identification point.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, a temporary symbol identification point is detected from a sampling sequence of L symbols (L: natural number) of a received baseband signal oversampled by M times (M: natural number). And a storage means for storing a sample position number of the symbol identification point when the temporary symbol identification point is detected N times (N: natural number) continuously by the temporary symbol identification point detection means. And the frequency for each sample position number of the N temporary symbol identification points stored in the storage means is aggregated, and the sample position number having the highest frequency is determined as the sample position number of the true symbol identification point. The symbol identification point detecting means is provided.
[0028]
According to the above configuration, the true symbol identification point detecting means uses the symbol identification points detected from the sampling sequence for L symbols as temporary identification points, and N temporary symbol identifications obtained by repeating this N times. A point having the highest frequency of the sample position numbers of points is determined as a true symbol identification point. This suppresses the deterioration of the symbol discrimination point detection performance when using a section with a low received electric field level, and improves the symbol discrimination point detection performance.
[0029]
According to a second aspect of the present invention, the true symbol identification point detecting means detects the first consecutive N times (N: natural number) of temporary symbol identification when there are a plurality of largest sample position numbers. The second consecutive N temporary symbol identification points are detected in a time zone shifted from the frame timing assumed in the point detection, and the sample positions of the new N temporary symbol identification points stored thereby The frequency for each number may be aggregated and the sample position number with the highest frequency may be determined as the sample position number of the true symbol identification point.
[0030]
According to the above configuration, even if it may be difficult to identify the true symbol identification point from the frequency of each sample position number of the first symbol identification point, the second consecutive N temporary symbols Identification point detection is performed, and symbol identification points are determined from the frequency distribution of the sample position numbers of the new N temporary symbol identification points obtained thereby. As a result, the symbol identification point can be detected with high performance even in communication in which modulated waves and non-modulated waves are mixed.
[0031]
Further, as described in claim 3, the true symbol identification point detecting means of claim 2 repeats the processing of claim 2 as many times as specified in advance when there are a plurality of largest sample position numbers. It may be determined as the sample position number of the true symbol identification point. When it is difficult to determine the symbol identification point in this way, it becomes possible to detect the symbol identification point by detecting N temporary symbol identification points in succession a plurality of times.
[0032]
Claim 4 of the present invention provides a temporary symbol identification check for detecting a temporary symbol identification point from a sampling sequence of L symbols (L: natural number) of the received baseband signal oversampled by M times (M: natural number). Output means; storage means for storing a sample position number of the symbol identification point when the temporary symbol identification point is detected N times (N: natural number) continuously by the temporary symbol identification point detection means; The frequency distribution of the sample position numbers of the N temporary symbol identification points stored in the means is created, and an optimum sample position number is selected based on the distribution bias in the vicinity of a specific consecutive sample position number. And a true symbol discrimination point detecting means for determining the sample location number of the symbol discrimination point.
[0033]
According to the above configuration, the temporary symbol identification point detection means can calculate not only the sample position number of the true symbol identification point but also the sample position number slightly deviated from the sample position number of the true symbol identification point. High nature. However, in order to determine the sample position number of the most likely symbol identification point in the vicinity where the frequency distribution of the sample position number of the obtained N temporary symbol identification points is biased using this property, the symbol identification point Can be detected with better performance.
[0034]
According to the symbol identification point detection apparatus of claim 5, the true symbol identification point detection means is configured to perform the first consecutive N times (when the distribution is biased near a plurality of consecutive sample position numbers). (N: natural number) for the second consecutive N temporary symbol identification points detected in the time zone shifted from the frame timing assumed in the detection of the temporary symbol identification points (N), and the new N number stored Creates a frequency distribution of sample position numbers for the temporary symbol identification points of and selects the optimal sample position number based on the distribution bias near a specific consecutive sample position number to select the true symbol identification point sample position Determine as a number.
[0035]
According to the above configuration, even if it is difficult to select the true symbol identification point from the deviation of the frequency distribution of each sample position number of the first symbol identification point, the first consecutive N times The N consecutive temporary symbol identification points are detected for the second time in a time zone shifted from the frame timing assumed for the temporary symbol identification point detection, and new N temporary symbols obtained thereby are detected. The symbol identification point can be detected from the deviation of the frequency distribution of each sample position number of the identification point. In addition, since the symbol identification point is determined not from the frequency but from the frequency distribution bias, the symbol identification point can be detected with higher performance even in communication in which modulated waves and non-modulated waves are mixed.
[0036]
Further, as described in claim 6, the true symbol identification point detecting means according to claim 5 is the same as the number of times designated in advance when the distribution is biased near a plurality of consecutive sample position numbers. The processing described in Item 5 may be repeated to determine the sample position number of the true symbol identification point. When it is difficult to determine the symbol identification point in this way, it becomes possible to detect the symbol identification point by detecting N temporary symbol identification points in succession a plurality of times.
[0037]
The mobile radio apparatus according to claim 7, wherein the I-side and Q-side quadrature detection input terminals and the I-side and Q-side quadrature detection results are oversampled at a symbol rate M times (M: natural number), and sampling data 7. An A / D converter that outputs a signal, and a processing unit that detects a symbol identification point based on a conversion output of the A / D converter, wherein the processing unit detects the symbol identification point according to claim 1. It is characterized by comprising an apparatus. According to such a configuration, the symbol identification point can be accurately detected only by adding a simple configuration in which the symbol identification point detecting means is added to the basic configuration of the mobile radio apparatus. It is possible to detect the symbol identification point with good performance even when the reception electric field level at the time of wireless reception is low.
[0038]
In addition, the symbol discrimination point detection method of the present invention is a provisional method based on a sampling sequence of L symbols (L: natural number) of the received baseband signal oversampled by M times (M: natural number). A symbol identification point is detected, and when the temporary symbol identification point is detected N times (N: natural number) continuously, a sample position number of the symbol identification point is stored, and the stored N temporary symbol identifications are stored. The frequency for each sample position number of the points is tabulated, and the sample position number having the highest frequency is determined as the sample position number of the true symbol identification point.
[0039]
According to such a configuration, the symbol identification point can be accurately detected by a simple procedure, and the configuration of the apparatus can be simplified.
[0040]
According to a ninth aspect of the present invention, a temporary symbol identification point is detected from a sampling sequence of L symbols (L: natural number) of a received baseband signal oversampled by M times (M: natural number), and the temporary symbol identification point is detected. When the symbol identification point is detected N times (N: natural number) continuously, the sample position number of this symbol identification point is stored, and the frequency distribution of the stored sample position numbers of the N temporary symbol identification points is stored. And generating a sample position number that is most likely in the vicinity of the specific consecutive sample position number, and determining the sample position number as a true symbol identification point. And
[0041]
According to the above configuration, the symbol identification point can be detected more accurately with a simple procedure, and the symbol identification point can be detected with a simple configuration without significantly changing the configuration of the apparatus.
[0042]
(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0043]
First, the symbol identification point detection apparatus of the present invention will be described with reference to FIGS.
[0044]
FIG. 1 is a block diagram of a symbol identification point detection apparatus for a mobile radio apparatus according to the present invention.
[0045]
In FIG. 1, an input 1 of the I-side quadrature detection result and an input 2 of the Q-side quadrature detection result of the radio unit are input to the A / D converters 3 and 4, respectively.
[0046]
The temporary symbol identification point detection means 5 detects a temporary symbol identification point from the sampling data input from the A / D converters 3 and 4.
[0047]
The storage means 6 stores sample position numbers of N temporary symbol identification points detected N times consecutively.
[0048]
The true symbol identification point selection means 7 uses the method described in the following first to fourth embodiments to sample positions of the N temporary symbol identification points detected by the temporary symbol identification point detection means 5. The sample position number of the true symbol identification point is selected and determined from the numbers.
[0049]
Next, with regard to the operation of the symbol discrimination point detection apparatus of the present invention configured as shown in FIG. 1, the operation common to the respective embodiments will be described first.
[0050]
The I-side quadrature detection result 1 and the Q-side quadrature detection result 2 are continuous waveforms with respect to time t as shown in FIGS. 2 and 3, respectively. The I-side quadrature detection result is input to the A / D converter 3, and the input waveform is oversampled at M times the symbol rate and converted into discrete sampling data as shown in FIG.
[0051]
4, T is a symbol interval, Ts is a sampling interval, Sn (n = 0, 1,..., M−1) is a sample at sample position number n, and FIG. 4 is an example in which the oversampling rate is M = 8. is there.
[0052]
On the other hand, the Q-side quadrature detection result 2 is input to the A / D converter 4, and the input waveform is oversampled at M times the symbol rate and converted into discrete sampling data as shown in FIG.
[0053]
5, T is a symbol interval, Ts is a sampling interval, Sn (n = 0, 1,..., M−1) is a sample at sample position number n, and FIG. 5 is an example in which the oversampling rate is M = 8. is there.
[0054]
Next, the I-side sampling data and the Q-side sampling data for L symbols output from the A / D converter 3 and the A / D converter 4, that is, L × M sample data on the I side and the Q side, respectively. The temporary symbol identification point detection means 5 is operated once based on the data input to the temporary symbol identification point detection means 5.
[0055]
After this, since the operation differs between the first to fourth embodiments, each embodiment will be described in detail.
[0056]
(Embodiment 1)
First, the operation of the symbol discrimination point detection apparatus according to the first embodiment of the present invention will be described using the flowchart of FIG.
[0057]
In FIG. 6, step S102 corresponds to the operation of the temporary symbol identification point detection means 5 in FIG. 1, and step S103 corresponds to the operation of the storage means 6 in FIG. Steps S105 to S108 correspond to the operation of the true symbol identification point selection means 7 in FIG.
[0058]
First, when i = 1 in step S101, L-symbols of the I-side sampling data and the Q-side sampling data output from the A / D converter 3 and the A / D converter 4 are detected as temporary identification points. The sample position number of the first temporary symbol identification point input to the means 5 is selected from 0 to M-1 (step S102). The sample position number of the selected temporary symbol identification point is input to the storage means 6 and stored in Sp [1] (step S103), and the first detection of the temporary symbol identification point is completed (step S104). ).
[0059]
Further, for i = 2 to i = N, the operations from step S101 to step S104 are performed in the same manner as described above. Finally, the sample position numbers of the N temporary symbol identification points are Sp [1] to Sp. [N].
[0060]
Next, the sample position numbers Sp [1] to Sp [N] of the N temporary symbol identification points are input to the true symbol identification point selection means 7 and stored in Sp [1] to Sp [N]. Among the sample position numbers 0 to M-1, the one with the highest frequency is searched for (step S105).
[0061]
In step S106, it is confirmed whether or not the sample position number having the maximum frequency is one. If it is one, the process proceeds to step S107. If there are more than one, the process proceeds to step S108.
[0062]
In step S107, only one sample position number having the highest frequency is output as symbol identification point information.
[0063]
In step S108, a true symbol identification point is randomly selected from a plurality of sample position numbers having the highest frequency, and used as symbol identification point information.
[0064]
Next, an operation example of the first embodiment will be described using specific numerical values.
[0065]
Assume that the mobile radio apparatus receives a radio format as shown in FIG. In FIG. 7, all received waves are modulated waves, and a waveform subjected to some modulation is transmitted. In addition, it is assumed that the part enclosed by the ellipse is near the boundary line inside and outside the service area, the section where the received electric field level is low due to low speed fading or shadow wing, etc., and the other parts have sufficiently high received electric field level Assume that
[0066]
Further, it is assumed that the oversampling rate of the A / D converters 3 and 4 is M = 8, and the sample position number of the true symbol identification point at this time is 4.
[0067]
At this time, sampling data for ¼ time of one frame time, that is, sampling data for L symbols is used for one temporary symbol identification point detection when one frame is 4L symbols. Suppose that temporary symbol identification point detection is performed four times (N = 4) from the section A1 to the section A4 (steps S101 to S104).
[0068]
If the sample position numbers Sp [1] to Sp [4] of the four temporary symbol identification points in this case are obtained by the temporary symbol identification point detection means 5 as shown in FIG. Since the frequency of 4 is only one maximum, the true symbol discrimination point selection means 7 outputs the sample position number 4 as symbol discrimination point information (step S105 to step S107).
[0069]
If the sample position numbers Sp [1] to Sp [4] of the four temporary symbol identification points in this case are obtained by the temporary symbol identification point detection means 5 as shown in FIG. Since there are a plurality (0 and 4) of sample position numbers with the maximum value, the true symbol discrimination point selection means 7 outputs sample location numbers 0 or 4 as symbol discrimination point information. (Step S105, Step S106 and Step S108).
[0070]
Now, the sample position number of the true symbol identification point is 4, but in FIG. 8 used for the description in the above specific numerical example, only Sp [1] out of Sp [1] to Sp [4] is included. Incorrect sample position number (0). This is because the first temporary symbol identification point detection is performed using a section with a small received electric field level in section A1 in FIG.
[0071]
However, according to the first embodiment, the temporary symbol identification point detection is performed four times, and the true symbol identification point is determined by the sample position number having the highest frequency. The number (4) will be selected.
[0072]
In the conventional symbol identification point detection apparatus, the symbol identification point is detected only once using the sampling data for L symbols. However, if the conventional symbol identification point detection apparatus detects the symbol identification point in FIG. If a section with a small received electric field level in section A1 is used, an incorrect sample position number (0) is detected.
[0073]
(Embodiment 2)
Next, the operation of the second embodiment of the symbol discrimination point detection apparatus of the present invention will be described using the flowchart of FIG.
[0074]
10, step S202 corresponds to the operation of the temporary symbol identification point detection means 5 in FIG. 1, and step S203 corresponds to the operation of the storage means 6 in FIG. Steps S205 to S210 correspond to the operation of the true symbol identification point selection means 7 in FIG.
[0075]
First, when i = 1 in step S201, the L side sampling data and the Q side sampling data output from the A / D converter 3 and the A / D converter 4 detect provisional discrimination points. The sample position number of the first temporary symbol identification point input to the means 5 is selected from 0 to M-1 (step S202). The sample position number of the selected temporary symbol identification point is input to the storage means 6 and stored in Sp [1] (step S203), and the first detection of the temporary symbol identification point is completed (step S204). ).
[0076]
Further, for i = 2 to i = N, the operations from step S201 to step S204 are performed in the same manner as described above. Finally, the sample position numbers of the N temporary symbol identification points are Sp [1] to Sp. [N].
[0077]
Next, the sample position numbers Sp [1] to Sp [N] of the N temporary symbol identification points are input to the true symbol identification point selection means 7 and stored in Sp [1] to Sp [N]. Among the sample position numbers 0 to M-1, the one with the highest frequency is searched for (step S205).
[0078]
In step S206, it is confirmed whether or not there is one sample position number having the maximum frequency. If there is one, the process proceeds to step S207. If there are more than one, the process proceeds to step S208.
[0079]
In step S207, only one sample position number having the highest frequency is output as symbol identification point information.
[0080]
Step S208 is processing for determining whether or not to repeat Step S201 to Step S205 again when there are a plurality of sample position numbers having the maximum frequency. If the number of times designated in advance has already been completed, Step S208 is performed. In S209, if the number of times designated in advance is not completed, the process proceeds to step S201.
[0081]
In step S209, a true symbol identification point is randomly selected from a plurality of sample position numbers having the highest frequency, and is output as symbol identification point information.
[0082]
In step S210, the start time of the next consecutive N temporary symbol identification point detections is adjusted. As the start time, a start time shifted from the frame timing assumed in the previous N consecutive temporary symbol identification point detections is selected. The selected start time information is transferred to the temporary symbol identification point detection means 5.
[0083]
In S201 transferred from Step S210, N consecutive temporary symbol identification point detections are performed again based on the start time information selected in Step S210 (from Step S201 to Step S204). Repeated.
[0084]
Next, an operation example of the second embodiment will be described using specific numerical values.
[0085]
Assume that the mobile radio apparatus receives a radio format as shown in FIG. In FIG. 11, the blacked out portion is a non-modulated wave that has not been modulated, and is a section used for transmission side training or the like of a base station or the like, and an arbitrary waveform whose band is limited is transmitted. This is a section.
[0086]
Further, in FIG. 11, the portion other than the portion painted in black is a modulated wave, and is a section in which a waveform subjected to some modulation is transmitted.
[0087]
At this time, sampling data for ¼ time of one frame time, that is, when one frame is 4L symbols, sampling data for L symbols is used for one temporary symbol identification point detection. It is assumed that provisional symbol identification point detection is performed four times (N = 4) from the section B1 to the section B4. In addition, when there are a plurality of sample position numbers having the highest frequency, the number of times designated in advance (used in step S208) is two as the number of repetitions of N consecutive temporary symbol identification point detections.
[0088]
Further, it is assumed that the oversampling rate of the A / D converters 3 and 4 is M = 8, and the sample position number of the true symbol identification point at this time is 4.
[0089]
If the sample position numbers Sp [1] to Sp [4] of the four temporary symbol identification points in this case are obtained as shown in FIG. 12 by the temporary symbol identification point detection means 5 (from step S201) In step S204), since there are a plurality of sample position numbers (0 and 4) having the highest frequency, the process proceeds from step S206 to step S208.
[0090]
In step S208, since the number of times designated in advance is 2, since the temporary symbol identification point in the continuous four times is performed only once, the process proceeds to step S210.
[0091]
In step S210, the frame timing assumed in detecting the symbol identification point is shifted, and the process proceeds to step S201.
[0092]
As a result of Step S201 to Step 205, the sample position numbers Sp [1] to Sp [4] by the second consecutive four temporary symbol identification point detection are obtained by the symbol identification point detection means 5 as shown in FIG. Suppose that it was obtained. In this case, since the frequency of the sample position number 4 is the largest, the sample position number 4 is output as the symbol identification point information (step S207).
[0093]
In the specific numerical example described above, the sample position numbers Sp [1] to Sp [4] of the temporary symbol identification points are different between the first four consecutive temporary symbol identification point detections and the second time. This is because, for the first time, B3 and B4 in the section from B1 to B4 in FIG. 11 perform temporary symbol identification points in the section where the modulated wave and the non-modulated wave are mixed. The discriminating point is likely to be wrong, and the remaining two sections are likely to be correct. On the other hand, the second time, only the section C3 in the section from C1 to C4 in FIG. 11 performs the temporary symbol identification point detection in the section where the modulated wave and the non-modulated wave are mixed. This is because there is a high possibility that the provisional symbol identification point is erroneous, and the remaining three sections are likely to be correct.
[0094]
For example, when the operation of the first embodiment described above is applied to the wireless format of FIG. 11, if the first time is as shown in FIG. 12, the wrong sample position number 0 or the correct sample position number 4 is selected. On the other hand, in the second embodiment, since the correct sample position number 4 is selected as described above, the symbol discrimination point detection performance is improved as compared with the first aspect.
[0095]
(Embodiment 3)
Next, the operation of the symbol identification point detection apparatus according to the third embodiment of the present invention will be described using the flowchart of FIG.
[0096]
14, step S302 corresponds to the operation of the temporary symbol identification point detection means 5 in FIG. 1, and step S303 corresponds to the operation of the storage means 6 in FIG. Steps S305 to S308 correspond to the operation of the true symbol identification point selection means 7 in FIG.
[0097]
First, when i = 1 in step S301, L-symbols of I-side sampling data and Q-side sampling data output from the A / D converter 3 and the A / D converter 4 are detected as temporary identification points. The sample position number of the first temporary symbol identification point input to the means 5 is selected from 0 to M−1 (step S302). The sample position number of the selected temporary symbol identification point is input to the storage means 6 and stored in Sp [1] (step S303), and the first detection of the temporary symbol identification point is completed (step S304). ).
[0098]
Further, for i = 2 to i = N, the operations from step S301 to step S304 are performed in the same manner as described above. Finally, the sample position numbers of the N temporary symbol identification points are Sp [1] to Sp. [N].
[0099]
Next, the sample position numbers Sp [1] to Sp [N] of the N temporary symbol identification points are input to the true symbol identification point selection means 7 and stored in Sp [1] to Sp [N]. A frequency distribution of sample position numbers 0 to M−1 is created. Further, it is searched whether the frequency distribution is biased near a certain continuous sample position number (step S305).
[0100]
In step S306, it is confirmed whether or not there is one portion where the frequency distribution is biased. If there is one, the flow proceeds to step S307. If there are more than one, the process proceeds to step S308.
[0101]
In step S307, the most likely sample position number is output as symbol identification point information from the vicinity of the sample position number where one frequency distribution is biased.
[0102]
In step S308, the most likely sample position number is selected from each of the vicinity of the sample position numbers where the plurality of frequency distributions are biased, and a true symbol identification point is selected at random from these sample position numbers. Are output as symbol identification point information.
[0103]
Next, the operation of the true symbol identification point selection means 7 in Embodiment 3 will be described using specific numerical values.
[0104]
Now, it is assumed that the oversampling rate of the A / D converters 3 and 4 is M = 8, and the sample position number of the true symbol identification point at this time is 4.
[0105]
At this time, one temporary symbol identification point detection is performed from the sampling data for L symbols, and 10 temporary symbol identification point samples obtained by performing this 10 times (N = 10) continuously. Assume that the frequency distribution of the position numbers is as shown in FIG.
[0106]
In this case, the frequency distribution of the sample position numbers of the temporary symbol identification points is clearly biased in the vicinity of the sample position numbers 4 and 5. Comparing the frequencies of sample position numbers 4 and 5, since the frequency of sample position number 4 is larger, the most likely sample position number is 4, and sample position number 4 is output as symbol identification point information.
[0107]
Further, it is assumed that the frequency distribution of the sample position numbers of ten temporary symbol identification points is as shown in FIG. 16 under the same conditions.
In this case, the frequency distribution of the sample position numbers of the temporary symbol identification points is biased in the vicinity of the sample position numbers 3 to 5. Comparing the frequencies of sample position numbers 3 to 5, the frequency of sample position number 4 is the largest, so the most likely sample position number is 4, and sample position number 4 is output as symbol identification point information.
[0108]
Further, it is assumed that the frequency distribution of the sample position numbers of the ten temporary symbol identification points is as shown in FIG. 17 under the same conditions.
[0109]
In this case, the frequency distribution of the sample position numbers of the temporary symbol identification points is biased near the sample position numbers 0 and 1 and near the sample position numbers 4 and 5. Comparing the frequencies of sample position numbers 0 and 1, since the frequency of sample position number 0 is larger, the most likely sample position number selected from the vicinity of sample position numbers 0 and 1 is 0.
[0110]
On the other hand, when the frequencies of the sample position numbers 4 and 5 are compared, the frequency of the sample position number 4 is larger, so the most likely sample position number selected from the vicinity of the sample position numbers 4 and 5 is 4. Therefore, sample position number 0 or 4 is selected at random and output as symbol identification point information.
[0111]
By the way, if the method of the first embodiment is applied to FIG. 16, the sample position number with the highest frequency is selected, so that the wrong sample position number 0 or the correct sample position number 4 is randomly selected. Will end up. However, according to the third embodiment, the correct sample position number 4 is selected.
[0112]
This is because reception performance deteriorates so much even when the received signal is demodulated using a sample position number (3 or 5 in this case) slightly deviated from the sample position number (4 in this case) of the true symbol identification point. In fact, the provisional symbol identification point detection means 5 utilizes the property that the sample position number slightly deviated from the sample position number of the true symbol identification point is likely to be calculated. As a result, it is possible to detect a symbol discrimination point with better performance than the symbol discrimination point detection apparatus described in the first embodiment.
[0113]
(Embodiment 4)
Next, the operation of Embodiment 4 of the symbol discrimination point detection apparatus of the present invention will be described using the flowchart of FIG.
[0114]
18, step S402 corresponds to the operation of the temporary symbol identification point detection means 5 in FIG. 1, and step S403 corresponds to the operation of the storage means 6 in FIG. Steps S405 to S410 correspond to the operation of the true symbol identification point selection means 7 in FIG.
[0115]
First, when i = 1 in step S401, L-symbols of I-side sampling data and Q-side sampling data output from the A / D converter 3 and the A / D converter 4 are detected as temporary identification points. The sample position number of the first temporary symbol identification point input to the means 5 is selected from 0 to M-1 (step S402). The sample position number of the selected temporary symbol identification point is input to the storage means 6 and stored in Sp [1] (step S403), and the first detection of the temporary symbol identification point is completed (step S404). ).
[0116]
Further, for i = 2 to i = N, the operations from step S401 to step S404 are performed in the same manner as described above. Finally, the sample position numbers of the N temporary symbol identification points are Sp [1] to Sp. [N].
[0117]
Next, the sample position numbers Sp [1] to Sp [N] of the N temporary symbol identification points are input to the true symbol identification point selection means 7 and stored in Sp [1] to Sp [N]. A frequency distribution of sample position numbers 0 to M−1 is created. Further, it is searched whether or not the frequency distribution is biased near a certain continuous sample position number (step S405).
[0118]
In step S406, it is confirmed whether or not there is one portion where the frequency distribution is biased. If there is one, the flow proceeds to step S407. If there are more than one, the process proceeds to step S408.
[0119]
In step S407, the most likely sample position number is output as symbol identification point information from the vicinity of the sample position number where one frequency distribution is biased.
[0120]
Step S408 is a process for determining whether or not to repeat step S401 to step S405 again when there are a plurality of locations where the frequency distribution is biased. If the number of times designated in advance has already been completed, step S408 is performed. If the predetermined number of times has not ended, the process proceeds to step S410.
[0121]
In step 409, the most likely sample position number is selected from each of the vicinity of the sample position numbers where the frequency distribution is biased, and the true symbol identification point is randomly selected from these sample position numbers. Are output as symbol identification point information.
[0122]
In step S410, the start time of the next consecutive N temporary symbol identification point detections is adjusted. As the start time, a start time shifted from the frame timing assumed in the previous N consecutive temporary symbol identification point detections is selected. The selected start time information is transferred to the temporary symbol identification point detection means 5.
[0123]
In step S401 transferred from step S410, based on the start time information selected in step S410, the N-th consecutive temporary symbol identification point detection is performed again, and step S401 to step S404). Thereafter, step S405 and subsequent steps are repeated. It is.
[0124]
Next, the operation of the true symbol identification point selection means 7 in Embodiment 4 will be described using specific numerical values.
[0125]
Now, it is assumed that the oversampling rate of the A / D converters 3 and 4 is M = 8, and the sample position number of the true symbol identification point at this time is 4. In addition, when there are a plurality of places where the frequency distribution is biased, the number of times of pre-designated N-number of temporary symbol identification point detections that is designated in advance (used in step S408) is two.
[0126]
At this time, one temporary symbol identification point detection is performed from the sampling data for L symbols, and 10 temporary symbol identification point samples obtained by performing this 10 times (N = 10) continuously. Assume that the frequency distribution of position numbers is as shown in FIG.
[0127]
In this case, the frequency distribution of the sample position numbers of the temporary symbol identification points is biased near the sample position numbers 0 and 1 and near the sample position numbers 4 and 5. That is, since there are a plurality of locations where the frequency distribution is biased, the process proceeds from step S406 to step S408.
[0128]
In step S408, since the number of times designated in advance is 2, ten temporary symbol identification point detections are currently performed only once, and the process proceeds to step S410.
[0129]
In step S410, the frame timing assumed in detecting the symbol identification point is shifted, and the process proceeds to step S401.
[0130]
As a result of step S401 to step S405, it is assumed that the frequency distribution of the sample position numbers by the second consecutive ten temporary symbol identification point detections is as shown in FIG. In this case, the sample position number 4 is output as the symbol identification point information for the same reason as described in FIG. 16 in the third embodiment (step S407).
[0131]
【The invention's effect】
According to the symbol identification point detection apparatus of the first aspect of the present invention, the symbol identification points detected from the sampling sequence for L symbols are used as temporary identification points, and N temporary symbols obtained by repeating this N times are obtained. In order to determine that the frequency of the sample position number of the identification point is the maximum as a true symbol identification point, it is possible to suppress deterioration of the symbol identification point detection performance when using a section with a low received electric field level, which has been a problem in the past, There is an effect that the symbol discrimination point detection performance can be improved.
[0132]
According to the symbol identification point detection apparatus of claim 2, even if it may be difficult to identify the true symbol identification point from the frequency of each sample position number of the first symbol identification point, In order to determine the symbol identification point from the frequency distribution of the sample position numbers of the new N temporary symbol identification points obtained by detecting N consecutive temporary symbol identification points in succession, the modulated wave and the non-modulation Symbol communication points can be detected with good performance even in communication with mixed waves.
[0133]
According to the symbol identification point detection apparatus of claim 4, the reception performance is not degraded even when the received signal is demodulated using the sample position numbers before and after the sample position number of the true symbol identification point. The provisional symbol identification point detecting means has a high probability that not only the sample position number of the true symbol identification point but also the sample position number slightly deviated from the sample position number of the true symbol identification point is calculated. In order to determine the sample position number of the most likely symbol identification point in the vicinity where the frequency distribution of the sample position numbers of the N temporary symbol identification points obtained is biased, It will be possible to perform well.
[0134]
According to the symbol identification point detection device of claim 5, even if it is difficult to select a true symbol identification point from the bias of the frequency distribution of each sample position number of the first symbol identification point, The second consecutive N temporary symbol identification points were detected in the time zone shifted from the frame timing assumed in the first consecutive N temporary symbol identification point detection, and thus obtained. The symbol identification point can be detected from the deviation of the frequency distribution of each sample position number of the new N temporary symbol identification points. In addition, since the symbol identification point is determined not from the frequency but from the frequency distribution bias, the symbol identification point can be detected with higher performance even in communication in which modulated waves and non-modulated waves are mixed.
[Brief description of the drawings]
FIG. 1 is a block diagram of a symbol discrimination point detection apparatus according to the present invention.
Fig. 2 I-side quadrature detection output
[Figure 3] Q-side quadrature detection output
FIG. 4 shows input sampling data I of symbol discrimination point detection means.
FIG. 5 shows input sampling data Q of symbol discrimination point detection means.
FIG. 6 is an operation flowchart according to the first embodiment.
FIG. 7 is a wireless format for explaining the operation of the first embodiment;
8 is a frequency example (1) of a sample position number of a temporary symbol identification point according to Embodiment 1. FIG.
9 is a frequency example (2) of the sample position number of the temporary symbol identification point according to the first embodiment.
FIG. 10 is an operation flowchart according to the second embodiment.
FIG. 11 is a radio format for explaining the operation of the second embodiment;
12 shows a frequency example of the sample position number of the first temporary symbol identification point in Embodiment 2. FIG.
FIG. 13 shows a frequency example of the sample position number of the second temporary symbol identification point in the second embodiment.
FIG. 14 is an operation flowchart according to the third embodiment.
FIG. 15 is a frequency distribution example (1) of sample position numbers of temporary symbol identification points according to the third embodiment;
FIG. 16 is a frequency distribution example (2) of sample position numbers of temporary symbol identification points according to the third embodiment;
FIG. 17 is a frequency distribution example (3) of sample position numbers of temporary symbol identification points according to the third embodiment;
FIG. 18 is an operation flowchart according to the fourth embodiment.
FIG. 19 shows an example of frequency distribution of sample position numbers of the first temporary symbol identification point according to the fourth embodiment.
20 shows an example of frequency distribution of sample position numbers of a second temporary symbol identification point according to Embodiment 4. FIG.
FIG. 21 is a configuration diagram of a conventional symbol identification point detection apparatus.
FIG. 22 is a radio format for explaining a conventional technique;
[Explanation of symbols]
1 I-side quadrature detection output
2 Q side quadrature detection output
3,4 A / D converter
5 Temporary symbol identification point detection means
6 Memory means
7 True symbol identification point detection means
101 I-side quadrature detection result
102 Q-side quadrature detection result
103,104 A / D converter
105 Symbol discrimination point detection means

Claims (9)

Provisional symbol identification point detection means for detecting a provisional symbol identification point from a sampling sequence of L symbols (L: natural number) of the received baseband signal oversampled by M times (M: natural number);
Storage means for storing a sample position number of the symbol identification point when the temporary symbol identification point is detected N times (N: natural number) continuously by the temporary symbol identification point detection means;
The true symbol which counts the frequency for each sample position number of the N temporary symbol identification points stored in the storage means and determines the sample position number having the highest frequency as the sample position number of the true symbol identification point Discrimination point detection means;
A symbol identification point detection apparatus comprising: The true symbol discrimination point detecting means, when there are a plurality of the largest sample position numbers, is the frame timing assumed in the first consecutive N (N: natural number) temporary symbol discrimination point detection. The second consecutive N temporary symbol identification points are detected in the shifted time zone, and the frequency for each sample position number of the new N temporary symbol identification points stored thereby is tabulated, The symbol identification point detection apparatus according to claim 1, wherein the largest sample position number is determined as a sample position number of a true symbol identification point. The true symbol identification point detection means according to claim 2 repeats the processing according to claim 2 as many times as specified in advance when there are a plurality of largest sample position numbers. A symbol identification point detection apparatus that determines a position number. Provisional symbol identification point detection means for detecting a provisional symbol identification point from a sampling sequence of L symbols (L: natural number) of the received baseband signal oversampled by M times (M: natural number);
Storage means for storing a sample position number of the symbol identification point when the temporary symbol identification point is detected N times (N: natural number) continuously by the temporary symbol identification point detection means;
A frequency distribution of sample position numbers of N temporary symbol identification points stored in the storage means is created, and an optimum sample position number is selected based on the distribution bias in the vicinity of a specific consecutive sample position number. True symbol identification point detecting means for determining the sample position number of the true symbol identification point;
A symbol identification point detection apparatus comprising: The true symbol discrimination point detection means assumes the first consecutive N (N: natural number) temporary symbol discrimination point detection when the distribution is biased near a plurality of consecutive sample position numbers. The second consecutive N tentative symbol identification points are detected in a time zone shifted from the previous frame timing, and the frequency distribution of the sample position numbers of the new N tentative symbol identification points stored thereby is obtained. 5. The processing according to claim 4, wherein an optimum sample position number is selected and determined as a sample position number of a true symbol identification point based on a distribution deviation in the vicinity of a specific consecutive sample position number. Symbol discrimination point detection device. The true symbol identification point detecting means according to claim 5 repeats the processing according to claim 5 by the number of times designated in advance when the distribution is biased near a plurality of consecutive sample position numbers. A symbol identification point detection apparatus that determines a sample position number of a symbol identification point. I-side and Q-side quadrature detection input terminals;
An A / D converter that oversamples the I-side and Q-side quadrature detection results at a symbol rate M times (M: natural number) and outputs sampling data;
Processing means for detecting a symbol identification point based on the conversion output of the A / D converter,
7. The mobile radio apparatus according to claim 1, wherein the processing means comprises the symbol identification point detection apparatus according to any one of claims 1 to 6. A temporary symbol identification point is detected from a sampling string of L symbols (L: natural number) of the received baseband signal oversampled by M times (M: natural number);
When the temporary symbol identification point is detected N times (N: natural number) continuously, the sample position number of this symbol identification point is stored,
The frequency for each sample position number of the stored N temporary symbol identification points is tabulated,
A symbol identification point detection method, wherein the sample position number having the highest frequency is determined as a sample position number of a true symbol identification point. A temporary symbol identification point is detected from a sampling string of L symbols (L: natural number) of the received baseband signal oversampled by M times (M: natural number);
When the temporary symbol identification point is detected N times (N: natural number) continuously, the sample position number of this symbol identification point is stored,
Creating a frequency distribution of sample position numbers of the stored N temporary symbol identification points;
A symbol identification characterized by selecting a sample position number most likely in the vicinity based on a biased distribution state in the vicinity of the specific consecutive sample position numbers and determining a sample position number of a true symbol identification point Point detection method.

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