JP5233512B2 - Propagation path estimation method and apparatus, and radio receiving apparatus - Google Patents

Description

  The present invention relates to a propagation path for performing propagation path correction in a receiving apparatus that receives a radio signal of a multicarrier (for example, OFDM (Orthogonal Frequency Division Multiplexing (including OFDMA)) method. The present invention relates to an estimation method and apparatus and a radio reception apparatus.

  An OFDM radio signal reaching the receiving apparatus is greatly affected by the reception environment of the receiving apparatus. In particular, when the receiver is on the ground that is susceptible to reflected waves from buildings, etc., or when the receiver moves, etc., the time-dependent reception due to frequency-dependent fluctuations or fading due to multipath. The fluctuation of intensity becomes large. For this reason, in order to reliably acquire information from the received signal, a propagation path correction technique that estimates the environment in which the radio signal is propagated and corrects the effects of multipath and fading based on this estimation result is effective. is there.

  For example, in the OFDM scheme, frequency fluctuations and temporal fluctuations of received pilot signals are evaluated using the fact that known pilot signals are regularly arranged. A technique for performing correction processing on a data carrier is known (see Patent Document 1).

  The OFDM method is also adopted as a wireless transmission method of WiMAX (Worldwide Interoperability for Microwave Access).

  In the WiMAX technology, in order to realize a multiple access in which a plurality of users are connected simultaneously, as shown in FIG. 2 (a) or FIG. 4 (a), a subband whose usage band is switched for each symbol (elapsed time) is used. Career placement.

  For example, when the uplink sub-channel usage (UL-PUSC) of IEEE 802.16e is permutation, two transmission diversity modes (STTD: space time transmit diversity) and In one transmission mode, pilot signals are distributed and arranged in units of bands (tiles) shown by a line for each 3 symbols × 4 subcarriers in FIG. 2A or 4A. In the two transmission diversity mode, as shown in FIG. 2A, two pilot signals are arranged at the diagonals of each tile, while in the one transmission mode, pilot signals are arranged at the four corners of the tile.

As described above, in a system to which a carrier arrangement in which pilot signals are irregularly distributed is applied, the above-described propagation path estimation in units of tiles is generally performed based on the distributed pilot signals. .
JP 2007-329626 A

  By applying the technology based on the regularity of pilot signal arrangement in the carrier arrangement as described above, transmission is performed using the entire carrier arrangement of the multicarrier (for example, OFDM, OFDMA) system as in digital terrestrial broadcasting. A highly accurate correction is realized in the receiving apparatus that receives a radio signal.

  However, a propagation path estimation technique similar to that of a terrestrial digital broadcast receiver cannot be applied as it is to a system to which a carrier arrangement in which pilot signals are irregularly distributed is applied as in the WiMAX technique.

  An object of the present invention is to provide a channel estimation method and apparatus that enable channel estimation corresponding to various channel environments in a multiple access system using a multicarrier scheme including OFDM and OFDMA.

  The above-described object can be achieved by a propagation path estimation method or apparatus that discloses a basic configuration below.

This propagation path estimation method or apparatus is characterized in that each region (which may be referred to as a tile in WiMAX) is a region (unit may be referred to as a tile) in which a pilot signal is disposed in a multicarrier (for example, OFDM, OFDMA) carrier arrangement. For two or more pilot signals included in (tile), a procedure (means) for estimating the propagation path based on the corresponding received signal, and a region (tile) based on the propagation path estimation value obtained for the pilot signal. for each data subcarrier belongs to the procedure (means) for obtaining the respective channel estimation values by at least one for the linear interpolation of the plurality of types of interpolation interval is different between a frequency axis direction and time axis direction, obtained by the plurality of types of linear interpolation procedure (means) to be subjected to selective channel compensation process either the propagation path estimated value and a, plurality of types Procedure for obtaining the channel estimation value by the shape interpolation (unit), for each region as a unit pilot signal is arranged, a plurality of which is provided on the reference straight line L _R that connects the pilot signals arranged in a diagonal region A procedure (means) for obtaining an interpolation value at each reference point by interpolation processing based on the propagation path estimation value obtained for the pilot signal, and propagation path estimation for each data subcarrier included in the region based on each interpolation value And a procedure (means) for obtaining a value .

  In the propagation path estimation method or apparatus configured in this way, at least one of the frequency axis direction and the time axis direction is interpolated based on the propagation path estimation value obtained for the pilot signal arranged in each region (tile). A propagation path estimation value for each data subcarrier is obtained by a plurality of types of linear interpolation processing with different intervals. In other words, by switching between multiple types of linear interpolation processing, for example, the interpolation interval in the time axis direction can be reduced to obtain a channel estimation value with high fading resistance, or the interpolation interval in the frequency axis direction can be reduced to achieve multipath. It is possible to acquire a propagation path estimation value having high tolerance.

  Further, the above-described object can be achieved by a wireless reception device that discloses a basic configuration below.

The wireless receiving apparatus is characterized by reference estimation means for performing propagation path estimation for two or more pilot signals included in each area for each area serving as a unit in which pilot signals are arranged in the carrier arrangement of the multicarrier scheme, and a pilot Based on the channel estimation value obtained for the signal, for each data subcarrier belonging to the region, the channel estimation value is obtained by a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. A plurality of carrier estimation means to be obtained and reception data demodulated from a reception signal that has been subjected to propagation path compensation by a propagation path estimation value for each data subcarrier obtained by any of the plurality of carrier estimation means is selectively output. and a selection means, a plurality of carrier estimation means, the pilot signal is arranged For each area to be a unit, the interpolated value at each of a plurality of reference points provided on the reference straight line L _R that connects the pilot signals arranged in a diagonal region, based on the channel estimation value obtained for the pilot signal an interpolation value calculating means for calculating by interpolation, there each interpolation value obtained by the interpolation value calculating means, in that Ru and a application means for applying a channel estimate for each data subcarrier included in the region.

  In the radio reception apparatus configured as described above, propagation for each data subcarrier is performed by a plurality of types of linear interpolation processes as described above based on the propagation path estimation values obtained for the pilot signals arranged in each region. A path estimation value is obtained, and reception data demodulated from the reception signal that has been subjected to propagation path compensation by any of these is selectively output by the selection means. For example, depending on the reception environment, the received signal that has been subjected to propagation path compensation using a propagation path estimation value with high fading resistance is subjected to demodulation processing to obtain reception data, or a propagation path estimation value with high multipath resistance is used. The received signal that has been subjected to propagation path compensation can be subjected to demodulation processing to obtain received data.

  According to the propagation path estimation method and apparatus and the wireless reception apparatus having the basic configuration described above, it is necessary to match the reception environment based on the propagation path estimation value obtained for the pilot signal arranged in each tile. A propagation path estimation value having characteristics can be obtained. As a result, for the data subcarriers belonging to individual regions (tiles) discretely arranged in the carrier arrangement of the multicarrier scheme, a channel estimation value having characteristics required in the reception environment is obtained, and the received signal It can be used for propagation path compensation processing.

  When applied to WiMAX, it is possible to obtain the best received data by adapting to various reception environments in which each wireless reception device receiving the WiMAX service is placed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 shows an embodiment of a wireless reception device.

  In the radio reception apparatus shown in FIG. 1, a radio signal arriving at an antenna is received by a radio reception unit (RF unit) 201 and digitized by an analog-to-digital converter (ADC) 202, and then a guard interval (GI). The data is passed to the Fourier transform unit 204 through the removal unit 203. The propagation path compensation unit 205 shown in FIG. 1 performs propagation path compensation processing on the received signal Fourier-transformed by the Fourier transform unit 204 based on the propagation path estimation value obtained by the propagation path estimation device 210, thereby performing propagation path compensation. The received signal is subjected to processing by the demodulator 206.

In the propagation path estimation apparatus 210 shown in FIG. 1, pilot signals distributed in a multicarrier (OFDM, OFDMA) carrier arrangement are extracted by a pilot (Pilot) extraction unit 211 and transmitted to a propagation path fluctuation estimation unit 212. together passed, it is passed to one of the selection unit 213 via the channel interpolation unit _{214 1,} 214 2, 214 _3.

  The selection unit 213 illustrated in FIG. 1 connects the path between the propagation path interpolation unit 214 selected by the instruction from the control unit 215 and the pilot extraction unit 211, and the propagation path interpolation unit 214 selected the pilot signal. To pass. Further, the propagation path characteristic analysis unit 216 analyzes the Doppler frequency and multipath characteristics of the above-described pilot signal based on the estimation result by the propagation path fluctuation estimation unit 212, and based on the analysis result, the control unit 215 Then, the propagation path interpolation unit 214 that performs an interpolation process suitable for the propagation path characteristics is selected.

Next, a method for realizing propagation path interpolation having different characteristics by the _three propagation path interpolation units 214 ₁ , 214 ₂ , and 214 ₃ shown in FIG. 1 will be described.

  As shown in FIG. 2 (a), when IEEE 802.16e UL-PUSC is used as a permutation, it is composed of 3 symbols × 4 subcarriers in 2 transmission diversity mode (STTD). Two pilot signals (indicated by the shaded circles in FIG. 2) are arranged on the diagonals of each tile, and the other pair of diagonal signals is a null carrier (indicated by the hatched circles in FIG. 2). Is shown). The data subcarriers belonging to each tile are indicated by white circles in FIG.

In each tile shown in FIG. 2 (a), as shown in FIG. 2 (b), the reference straight line L _R connecting the two pilot signals arranged in a diagonal (P _1, P _2), data subcarriers (in FIG. 2 (b), reference numeral C _D are denoted a) one passes the intersection between the carrier straight line L _C that intersects in the frequency axis with a predetermined angle theta (triangles in FIG. 2 (b) code Can be obtained). Then, by linear interpolation of the propagation path estimated value obtained for the pilot signal described above, a propagation path estimated value corresponding to the position of this intersection can be obtained, and this propagation path estimated value is placed on the carrier straight line that gives this intersection. It can be a propagation path estimation value of a certain data carrier.

For example, as shown in FIG. 3, the three channel interpolation unit 214 1, _{214 2,} 214 _3, by performing linear interpolation according to the carrier line intersecting the frequency axis at different angles, the frequency axis direction and A channel estimation value for each data subcarrier can be obtained by applying different interpolation intervals in the time axis direction.

In the example shown in FIG. 3, with carriers crossing straight lines by the propagation path interpolation unit 214 _1, a relatively small angle theta ₁ between a frequency axis _{(e.g., θ 1 = 26.5 (= atan} (0.5))) Thus, linear interpolation processing is performed in which the interpolation density is increased in the time axis direction. Further, the interpolation density in the frequency axis direction by using the carrier straight lines intersecting at a relatively large angle theta ₃ and the frequency axis in the channel interpolation unit 214 _{3 (e.g., θ 3 = 63.5 (= atan} (2))) A raised linear interpolation process is performed. On the other hand, the propagation path interpolation unit 214 ₂ intersects at an angle θ ₂ (for example, θ ₂ = 45 (= atan (1))) having an intermediate size between the two propagation path interpolation units 214 ₁ and 214 ₂ described above. A linear interpolation process having intermediate characteristics is performed using the carrier straight line.

  Here, high fading tolerance can be obtained by obtaining a channel estimation value for each data subcarrier using linear interpolation processing with a higher interpolation density in the time axis direction. Conversely, interpolation is performed in the frequency axis direction. By obtaining a channel estimation value for each data subcarrier using linear interpolation processing with increased density, high multipath tolerance can be obtained.

Therefore, the control unit 215 determines which endurance is more strongly required in the reception environment based on the Doppler frequency and multipath characteristics obtained by the propagation path characteristic analysis unit 216, and corresponds to the determined endurance. The selection unit 213 may be instructed to input the pilot signal to the propagation path interpolation unit 214 to be transmitted. In other words, determination if it is determined that the fading resistance is required, the control unit 215 causes the input pilot signal via the selector 213 to the channel interpolation unit 214 _1, a multi-path resistance is required If it is controls the selection unit 213 so as to input the pilot signal to the channel interpolation unit 214 _3. Further, when both fading tolerance and multipath tolerance is required, the control unit 215 may control the selection unit 213 so as to input the pilot signal to the channel interpolation unit 214 _2.

In this manner, a plurality of channel interpolation unit 214 1 of different characteristics, _{214 2,} 214 ₃ switches the seek propagation path estimation value, subjecting the channel estimation value obtained in the processing of channel compensation unit 205 Thus, it is possible to perform propagation path compensation of the received signal in accordance with various receiving environments. By using the reception signal that has been appropriately subjected to propagation path compensation for the processing of the demodulation unit 206, the probability that the reception data is correctly demodulated can be improved.

Note that a propagation path estimation apparatus may be configured by including four or more propagation path interpolation units 214 having different characteristics. In each channel interpolation unit 214, the angle between the carrier straight line L _C and a frequency axis for obtaining an interpolation value corresponding to each data sub-carrier is not limited to the example described above, the frequency axis at different angles A propagation path interpolation unit 214 that performs linear interpolation processing using a carrier straight line that intersects the line can be provided. For example, in addition to the above-described propagation path interpolation units 214 ₁ , 214 ₂ , and 214 ₃ , the frequency axis intersects at an intermediate angle between the angles θ ₁ and θ ₂ and an intermediate angle between the angles θ ₂ and θ _3. It is also possible to configure a propagation path estimation apparatus by including a propagation path interpolation unit 214 that performs linear interpolation processing using a carrier straight line.

Also, as shown in FIG. 4A, when pilot signals are arranged at the four corners of each tile, as shown in FIG. 4B, a carrier straight line passing through the data subcarriers belonging to the tile (see FIG. 4B). 4 (b) is indicated by a broken line) and passes through other pilot signals P ₃ and P ₄ not connected by the reference straight line described above.

Interpolated values corresponding to the intersections of the pilot signals P ₃ and P _4, the carrier line passing through the data subcarriers, and the reference line (indicated by a square symbol in FIG. 4B) are connected by the reference line. The pilot signals P ₁ and P ₂ obtained by adding the pilot signal (P ₃ or P ₄ ) on the carrier line can be obtained by interpolation processing using the propagation path estimation values obtained for the three pilot signals. .

  In addition, the interpolation value obtained by the interpolation process using the propagation path estimation values obtained for the three pilot signals in this way is used as the intersection of the carrier straight line passing only the data subcarrier and the reference straight line (FIG. 4B). It can also be used to calculate an interpolation value corresponding to (indicated by a triangular symbol in FIG. 5). For example, two points close to the intersection of the carrier line that passes only the data subcarrier and the reference line are selected from two interpolated values obtained using three pilot signals and the two pilot signals connected by the reference line. Then, it can be used to calculate an interpolation value corresponding to the above-described intersection.

In each propagation path interpolation unit 214, based on the angle between the applied carrier straight line and the frequency axis, the reference straight line connecting the two pilot signals P ₁ and P ₂ , the above-described two kinds of intersections, and the intersections between them. The correspondence relationship with the data subcarrier to which the corresponding interpolation value is to be applied can be specified in advance.

Therefore, for example, as illustrated in FIG. 5, the above-described correspondence relationship is held in the arrangement information holding unit 223, and the interpolation value calculation unit 222 obtains the correspondence variation calculation unit 221 based on this correspondence relationship. Interpolation values corresponding to the two types of intersections described above can be calculated using the propagation path estimation values for the pilot signals. For example, the interpolation value calculation unit 222 first obtains an interpolation value corresponding to two intersections indicated by a square symbol in FIG. 4B using three pilot signals. Next, the interpolation value calculation unit 222 uses the two points selected based on the above-described correspondence relationship from the above-described two intersection points and the two pilot signals P ₁ and P ₂ , and assigns a triangle symbol to FIG. Interpolation values corresponding to the two intersections shown are added. The interpolation value corresponding to each intersection obtained in this way is applied as the channel estimation value of each data subcarrier by the estimation value determination unit 224 based on the above-described correspondence relationship. Provided for processing.

  In this way, by switching between the interpolation method using the three pilot signals and the interpolation method using two points selected from the points on the straight line connecting the two pilot signals, it is arranged at the four corners of the tile. By using the pilot signal thus obtained, it is possible to improve the accuracy of the propagation path estimated values having different characteristics obtained by the propagation path interpolation units 214.

  Instead of the interpolation method described above, as shown in FIG. 6, the pilot signals arranged at the four corners of the tile are divided into two sets of diagonals, and interpolation values are obtained for two reference lines connecting them. The channel estimation value for each data subcarrier can also be obtained based on the obtained interpolation value.

For example, two pilot signals P _1, the interpolation value D1 corresponding to the intersection of the carrier straight line passing through the reference line and data subcarriers connecting P ₂ (indicated by symbol C ₁₁ in FIG. 6), the other two pilots based on the value obtained by adding the interpolated value D2 corresponding to the intersection of the carrier line passing through the same data subcarrier C ₁₁ and the reference straight line connecting the signal P _3, P _4, the propagation path of the data sub-carrier C ₁₁ as described above An estimated value can be obtained. In the example shown in FIG. 6, the angle formed by the reference line connecting pilot signals P ₁ and P ₂ and the carrier line passing through data subcarrier C ₁₁ and the same data sub as the reference line connecting pilot signals P ₃ and P ₄ are used. as the carrier line passing through the carrier C ₁₁ and the angle is the same, the carrier linearly are set.

Thus, the estimation accuracy of the propagation path estimation value can be improved by obtaining the propagation path estimation value for each data subcarrier based on the interpolation values obtained for the two reference straight lines.
(Embodiment 2)
FIG. 7 shows another embodiment of the wireless reception device.

  7 that are the same as those shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

In the propagation path estimation apparatus 210 shown in FIG. 7, the pilot signal extracted by the pilot extraction unit 211 is input to all of the _three propagation path interpolation units 214 ₁ , 214 ₂ , 214 ₃ , and these propagation path interpolation units 214 ₁ , 214 ₂ , and 214 ₃ determine propagation path estimated values, respectively. Based on these propagation path estimated values, propagation path compensation processing for the received signal is performed by the corresponding propagation path compensating units 205 ₁ , 205 ₂ , and 205 ₃ provided in the wireless reception device, and the received signal after compensation is performed. The demodulating units 206 ₁ , 206 ₂ , and 206 ₃ respectively perform the demodulating processes.

  Likelihood determination section 207 shown in FIG. 7 calculates likelihood for each of the three systems of received data demodulated as described above, and likelihood processing such as maximum ratio combining based on the obtained likelihood information. To select and output the most likely received data. For example, when an error correction code such as Reed-Solomon or CRC is applied, the likelihood determination unit 207 can calculate the likelihood based on the error rate for each received data.

In this way, one of the received data obtained by demodulating the received signal compensated by using the propagation path estimated value obtained by each propagation path interpolation unit 214 prepared in the propagation path estimating apparatus 210 is selected. In the case of a configuration that outputs automatically, it is possible to select a channel estimation value from which the most likely received data is demodulated.
(Embodiment 3)
FIG. 8 shows another embodiment of the wireless reception device.

  8 that are the same as those shown in FIG. 1 or FIG. 7 are given the same reference numerals, and descriptions thereof are omitted.

In the channel estimation device 210 shown in FIG. 8, the channel estimation values obtained by the _three channel interpolation units 214 ₁ , 214 ₂ , and 214 ₃ are respectively obtained in the same manner as the channel estimation device 210 shown in FIG. The channel compensation units 205 ₁ , 205 ₂ , and 205 ₃ are subjected to channel compensation processing for received signals.

The likelihood determination unit 208 shown in FIG. 8 calculates the likelihood for each of the reception signals compensated by the propagation path compensation units 205 ₁ , 205 ₂ , and 205 ₃ , and the demodulation unit 206 determines the reception signal with the highest likelihood. Used for demodulation processing. The likelihood determination unit 208 is based on, for example, an error between complex data indicating the reception signal compensated by the above-described propagation path compensation units 205 ₁ , 205 ₂ , and 205 ₃ and complex data corresponding to the constellation in the transmission signal. Thus, the likelihood of each received signal can be calculated.

In this way, in the configuration in which any of the received signals compensated using the propagation path estimation values respectively obtained by the respective propagation path interpolation units 214 prepared in the propagation path estimation apparatus 210 is subjected to demodulation processing, It is possible to select a channel estimation value that provides the most likely received signal by compensation based on the channel estimation value.
(Embodiment 4)
FIG. 9 shows another embodiment of the wireless reception device.

  9 that are the same as those shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  In the channel estimation apparatus 210 shown in FIG. 9, the likelihood calculating unit 217 is based on the error rate of the received data demodulated by the demodulating unit 206 in the same way as the likelihood determining unit 207 of the second embodiment described above. Calculate the degree. Based on the likelihood calculated by the likelihood calculation unit 217, the control unit 215 controls the switching operation of the selection unit 213, and switches the propagation path interpolation unit 214 to which the pilot signal is passed from the pilot extraction unit 211.

  For example, when the likelihood received from the likelihood calculation unit 217 is equal to or less than a predetermined threshold, the control unit 215 determines that the propagation path estimation value being applied is no longer suitable for the reception environment. Is switched to the propagation path interpolation unit 214.

  The control unit 215 switches the channel interpolation unit 214 that provides the channel estimation value to the channel compensation unit as described above, and then the likelihood newly calculated by the likelihood calculation unit 217 and the predetermined threshold described above. (Or another threshold) can be compared, and based on the comparison result, it can be determined whether or not to maintain the current selection of the channel interpolation unit 214. For example, when the newly calculated likelihood exceeds the threshold value (or another threshold value) described above, the selection state of the propagation path interpolation unit 214 by the selection unit 213 is maintained, while the likelihood calculation unit 217 is maintained. Can be switched to another channel interpolation unit 214 via the selection unit 213.

Further, a propagation path interpolation unit 214 (propagation path interpolation) other than the propagation path interpolation unit 214 (for example, propagation path interpolation unit 214 ₁ ) selected when it is determined that the applied propagation path estimation value is not suitable for the reception environment. The control unit 215 performs control to sequentially select the units 214 ₂ , 214 ₃ ), and confirms the selection of the propagation path interpolation unit 214 based on the likelihood calculation result for the received data obtained in each case. You can also.

  Thus, based on the likelihood of the reception data demodulated by the demodulator 206, the channel interpolation unit 214 to which the pilot signal is passed through the selector 213 is switched to be provided to the process of the demodulator 206. The propagation path correction value used for propagation path compensation for the received signal can be switched.

(Embodiment 5)
FIG. 10 shows another embodiment of the wireless reception device.

  10 that are equivalent to the components shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  In the propagation path estimation apparatus 210 shown in FIG. 10, the likelihood calculation unit 218 constellation of the received signal that has been subjected to propagation path compensation by the propagation path compensation unit 205, similarly to the likelihood determination unit 208 of the third embodiment described above. Likelihood is calculated based on the deviation from. Based on the likelihood calculated by the likelihood calculation unit 218, the control unit 215 controls the switching operation of the selection unit 213 in the same manner as in the fifth embodiment described above, and a pilot signal is passed from the pilot extraction unit 211. The propagation path interpolation unit 214 to be switched is switched.

  As described above, the propagation path interpolation unit 214 to which the pilot signal is passed through the selection unit 213 is switched based on the likelihood obtained with respect to the reception signal that has been subjected to propagation path compensation. The propagation path correction value used for propagation path compensation for the received signal can be switched.

  Regarding the above description, the following items are further disclosed.

(Supplementary note 1) For each region serving as a unit in which pilot signals are arranged in the carrier arrangement of the multi-carrier scheme, for each of two or more pilot signals included in the region, channel estimation is performed based on the corresponding received signals,
Based on the propagation path estimation value obtained for the pilot signal, the propagation paths for each data subcarrier belonging to the region are each subjected to a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. Find an estimate,
One of the channel estimation values obtained by the plurality of types of linear interpolation is selectively used for channel compensation processing.

(Supplementary Note 2) corresponds to the intersection between the reference straight line L _R that connects the pilot signals arranged in a diagonal of the data sub-carriers belonging to the region and as the frequency axis to the carrier straight line L _C that intersect at different angles the area an interpolation value by the channel estimation value corresponding to the data subcarriers belonging to the region located on the carrier straight line L _C, the propagation of statement 1, characterized in that said plurality of types of linear interpolation Road estimation method.

(Supplementary Note 3) Reference estimation means for performing propagation path estimation for each of two or more pilot signals included in the region for each region serving as a unit in which pilot signals are arranged in the carrier arrangement of the multicarrier scheme,
Based on the propagation path estimation value obtained for the pilot signal, the propagation paths for each data subcarrier belonging to the region are each subjected to a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. A plurality of carrier estimation means for obtaining an estimated value;
A propagation path estimation apparatus comprising: selection means for providing a propagation path estimated value for each data subcarrier obtained by any of the plurality of carrier estimation means to a received signal compensation process.

(Supplementary Note 4) The plurality of carrier estimation means include
The interpolated value at the intersection of the reference straight line L _R that connects the pilot signals arranged in a diagonal of the carrier linearly L _C and each region through the putative target of one or more data subcarriers belonging to the region, on the diagonal Interpolated value calculating means obtained by interpolation processing based on propagation path estimated values for the arranged pilot signals;
An interpolation value obtained by the interpolation value calculating means, and a application means for applying a channel estimation value of the data subcarrier belonging to the region located on the carrier straight line L _C,
Wherein each estimated value calculating means, the propagation of statement 3, wherein the obtaining the channel estimation value at the intersection of the carrier linearly L _C and the reference straight line L _R that intersects the frequency axis direction at different angles from each other Road estimation device.

(Supplementary Note 5) The interpolated value calculating means, when the two sets of pilot signals in an area to be estimated is located, for the reference straight line L _R connecting the corresponding set of pilot signals, one or more belonging to the region includes two sets of intersection calculating means for calculating an interpolation value at the intersection between the carrier straight line L _C through the data sub-carriers,
The application means obtains a channel estimation value corresponding to the data subcarrier from the interpolation value at the intersection obtained by the two sets of intersection calculation means,
The two pairs of intersection calculation means and one set of the reference straight line L _R and the angle between the carrier straight line L _C through the data sub-carrier to be estimated, and the other set of the reference straight line L _R the data subcarriers Supplementary note that for each of the two straight lines passing through the data sub-carrier such as the angle between the carrier straight line L _C match, and obtains an estimate of the intersection of the straight line connecting the corresponding set of pilot signals through 5. The propagation path estimation apparatus according to 4.

(Supplementary Note 6) The interpolation value calculation means includes:
When two sets of pilot signals are arranged in the estimation target area,
When passing through the another pilot signal carrier linear L _C is not connected with the reference straight line L _R that passes through the one or more data subcarriers belonging to the region, and the reference straight line L _R of the carrier linearly L _C Three-point interpolation means for obtaining an interpolation value at an intersection based on three points of two pilot signals connected by the reference signal and the other pilot signal;
If that does not pass through a different pilot signal carrier linear L _C is not connected with the reference straight line L _R that passes through the one or more data subcarriers belonging to the region, and the reference straight line L _R and the carrier straight line L _C Two-point interpolating means for obtaining an interpolation value at the intersection of two points based on two points selected from the two pilot signals connected by the reference signal and the intersection obtained by the three-point interpolating means. The propagation path estimation apparatus according to appendix 4.

(Supplementary Note 7) Reference estimation means for performing channel estimation for each of two or more pilot signals included in the region, for each region serving as a unit in which pilot signals are arranged in the carrier arrangement of the multicarrier scheme,
Based on the propagation path estimation value obtained for the pilot signal, the propagation paths for each data subcarrier belonging to the region are each subjected to a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. A plurality of carrier estimation means for obtaining an estimated value;
Selecting means for selectively outputting received data demodulated from a received signal that has been subjected to propagation path compensation by a propagation path estimated value for each data subcarrier obtained by any of the plurality of carrier estimation means; A wireless receiver characterized by the above.

(Supplementary Note 8) The selection means includes:
A plurality of propagation path compensation means for correcting a corresponding received signal using a propagation path estimated value of each data subcarrier belonging to the region obtained by the corresponding carrier estimation means;
Likelihood calculating means for calculating a likelihood for a correction signal corresponding to each received signal belonging to the region obtained by the plurality of propagation path compensating means;
The wireless reception device according to appendix 7, further comprising: a determination unit that determines a correction signal having the highest likelihood based on the likelihood calculated by the likelihood calculation unit and uses the correction signal for demodulation processing.

(Supplementary Note 9) The selection means includes:
A plurality of propagation path compensation means for correcting a corresponding received signal using a propagation path estimated value of each data subcarrier belonging to the region obtained by the corresponding carrier estimation means;
A plurality of demodulation means for performing demodulation processing based on the correction signal obtained by the corresponding propagation path compensation means;
Likelihood calculating means for calculating likelihood for the received data obtained by the plurality of demodulating means;
The wireless reception device according to appendix 7, further comprising: discrimination means for discriminating and outputting reception data having the highest likelihood based on the likelihood calculated by the likelihood calculation means.

It is a figure which shows one Embodiment of a radio | wireless receiving apparatus. It is a figure explaining a propagation path estimation method. It is a figure explaining the characteristic of each propagation path interpolation part. It is a figure explaining another propagation path estimation method. It is a figure which shows the detailed structural example of a propagation path interpolation part. It is a figure explaining another propagation path interpolation method. It is a figure which shows another embodiment of a radio | wireless receiver. It is a figure which shows another embodiment of a radio | wireless receiver. It is a figure which shows another embodiment of a radio | wireless receiver. It is a figure which shows another embodiment of a radio | wireless receiver.

Explanation of symbols

201 Wireless receiver (RF unit)
202 Analog-to-digital converter (ADC)
203 Guard Interval (GI) Removal Unit 204 Fourier Transform Unit 205 Channel Compensation Unit 206 Demodulation Unit 207 Likelihood Determination Unit 210 Channel Estimation Device 211 Pilot Extraction Unit 212 Channel Variation Estimation Unit 213 Selection Units 214 ₁ , 214 ₂ , 214 ₃ Propagation channel interpolation unit 215 Control unit 216 Propagation channel characteristic analysis unit 217, 218 Likelihood calculation unit 221 Reference fluctuation calculation unit 222 Interpolation value calculation unit 223 Arrangement information holding unit 224 Estimated value determination unit

Claims (5)

For each region serving as a unit in which pilot signals are arranged in the carrier arrangement of the multicarrier scheme, for each of two or more pilot signals included in the region, channel estimation is performed based on the corresponding received signals,
Based on the propagation path estimation value obtained for the pilot signal, the propagation paths for each data subcarrier belonging to the region are each subjected to a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. Find an estimate,
And subjected to selective channel compensation process of any of the plurality of types of propagation path estimated value obtained by linear interpolation,
The process of obtaining the propagation path estimated value by the plurality of types of linear interpolation,
For each area as the unit of the pilot signal is disposed, the interpolated value at each of a plurality of reference points provided on a reference straight line L _R connecting the arranged pilot signals in a diagonal of the area, obtained for the pilot signal Obtained by interpolation based on the estimated propagation path value,
A channel estimation method , wherein the channel estimation value for each data subcarrier included in the region is obtained based on each interpolation value . In the propagation path estimation method according to claim 1,
The resulting interpolated values for the reference point corresponding to the intersection of the carrier line L _C before Symbol reference straight line L _R that intersect at an angle different from street the frequency axis data subcarriers belonging to the region, the carrier line L _A channel estimation method, wherein the plurality of types of linear interpolation are performed by using channel estimation values corresponding to data subcarriers belonging to the region on _C. Reference estimation means for performing channel estimation for each of two or more pilot signals included in the region for each region serving as a unit in which pilot signals are arranged in the carrier arrangement of the multicarrier scheme,
Based on the propagation path estimation value obtained for the pilot signal, the propagation paths for each data subcarrier belonging to the region are each subjected to a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. A plurality of carrier estimation means for obtaining an estimated value;
Selecting means for providing a propagation path estimation value for each data subcarrier obtained by any of the plurality of carrier estimation means for compensation processing of a received signal ;
The plurality of carrier estimation means include
For each area as the unit of the pilot signal is disposed, the interpolated value at each of a plurality of reference points provided on a reference straight line L _R connecting the arranged pilot signals in a diagonal of the area, obtained for the pilot signal Interpolated value calculating means to be obtained by interpolation processing based on the obtained propagation path estimated value;
Applying means for applying each interpolation value obtained by the interpolation value calculation means as a propagation path estimation value of each data subcarrier included in the region.
Channel estimation device characterized by and this. In the propagation path estimation apparatus according to claim 3,
Wherein each interpolation value calculation unit, the intersection of the carrier linearly L _C before Symbol reference straight line L _R that intersects the frequency axis direction one or more data subcarriers belonging to the area to be estimated at different angles Ri through It obtains the interpolated value at the reference point corresponding,
Wherein each application means, channel estimation device characterized in that said interpolation value obtained by the interpolation value calculating means, the channel estimation value of the data subcarrier belonging to the region located on the carrier straight line L _C . Reference estimation means for performing channel estimation for each of two or more pilot signals included in the region for each region serving as a unit in which pilot signals are arranged in the carrier arrangement of the multicarrier scheme,
Based on the propagation path estimation value obtained for the pilot signal, the propagation paths for each data subcarrier belonging to the region are each subjected to a plurality of types of linear interpolation with different interpolation intervals in at least one of the frequency axis direction and the time axis direction. A plurality of carrier estimation means for obtaining an estimated value;
Selecting means for selectively outputting received data demodulated from a received signal subjected to propagation path compensation by a propagation path estimated value for each data subcarrier obtained by any of the plurality of carrier estimation means ;
The plurality of carrier estimation means include
For each area as the unit of the pilot signal is disposed, the interpolated value at each of a plurality of reference points provided on a reference straight line L _R connecting the arranged pilot signals in a diagonal of the area, obtained for the pilot signal Interpolated value calculating means to be obtained by interpolation processing based on the obtained propagation path estimated value;
Applying means for applying each interpolation value obtained by the interpolation value calculation means as a propagation path estimation value of each data subcarrier included in the region.
Wireless receiving device comprising a call.

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