JPWO2006098301A1 - Multi-carrier signal receiver and multi-carrier signal receiving method - Google Patents

Abstract

Provided are a multicarrier signal receiver and a multicarrier signal reception method capable of realizing an increase in maximum throughput by accurately obtaining noise power and performing appropriate weighting even when propagation path fluctuations are fast. Using a pilot channel, a propagation path estimation unit that calculates a propagation path estimation value from a reception signal and a reference signal, a propagation path estimation value calculated by the propagation path estimation unit, a reception signal included in a small time interval, and a reference signal A multi-carrier signal receiver and a multi-carrier signal receiving method, comprising: a noise power estimation unit that calculates a noise power estimation value.

Description

The present invention relates to a multicarrier signal receiver and a multicarrier signal receiving method for receiving radio waves transmitted using a multicarrier system.
This application claims priority to Japanese Patent Application No. 2005-071579 filed on Mar. 14, 2005, the contents of which are incorporated herein by reference.

2. Description of the Related Art Recently, in a CDMA (Code Division Multiple Access) type multi-carrier signal receiver, weighting is performed for each carrier (hereinafter, also referred to as “subcarrier”), and demodulation is performed to maximize. A receiver capable of realizing an increase in transmission speed (maximum throughput) has been studied. As the method of weighting, MMSE for obtaining weighting coefficients _{w m} from the channel estimation value _{h m} and the noise power estimate N: method (Minimum Mean Square Error minimum mean square error) combining is to be obtained the good characteristics .
A CDMA multi-carrier signal receiver using the MMSE combining method is described in Non-Patent Document 1.

In addition, a frame configuration in which not only the pilot channel PICH is inserted before and after the frame but also the PICH is inserted at the center of the frame has been proposed (Non-Patent Document 2).
"Science Technical Report RCS2001-166" published by The Institute of Electronics, Information and Communication Engineers October 2001 “Science Technical Report RCS2002-85” The Institute of Electronics, Information and Communication Engineers issued in June 2002

However, the conventional method cannot accurately determine the effective weighting factor w _m because noise cannot be accurately determined, and therefore cannot increase the maximum throughput as expected. was there.
In other words, the time interval between frames is usually designed so that the fluctuation of the propagation path becomes sufficiently small even when the fluctuation of the propagation path is fast (the maximum Doppler frequency is large). There is a slight monotonous change before and after this, but this does not adversely affect the demodulation of the received signal. However, the difference between the actual channel and the channel estimation value h _m is, while the very small at the midpoint vicinity of the frame, caused a slight difference before and after the frame, increases the difference in the noise power estimate interest It becomes the cause of bringing about the said fault. In addition, when the power of the pilot channel PICH is increased compared to the power of the data traffic channel DTCH, the channel fluctuation component is proportional to the power of the PICH, whereas the noise power is independent of the power of the PICH. The channel fluctuation component is observed to be enlarged as compared with the noise component, which causes the above-mentioned defect.

  The present invention has been made in view of the above circumstances, and an object thereof is to realize an increase in maximum throughput by accurately obtaining noise power and performing appropriate weighting even when the propagation path changes rapidly. To provide a multicarrier signal receiver and a multicarrier signal reception method.

  A multicarrier signal receiver according to a first aspect of the present invention includes a propagation path estimation unit that calculates a propagation path estimated value from a received signal and a reference signal using a pilot channel included in a first time interval, and the propagation Noise power from the received signal and the reference signal located near the midpoint of the first time interval among the propagation path estimated value calculated by the path estimation unit and the signal included in the first time interval. A multicarrier signal receiver having a noise power estimation unit for calculating an estimated value.

  The multicarrier signal receiver according to the second aspect of the present invention uses a pilot channel included in the first time interval to calculate a demodulation channel estimation value from the received signal and the reference signal. A propagation path estimation unit that calculates a propagation path estimation value for replica creation from a received signal and a reference signal using a pilot channel included in a small time interval in the first time interval. Noise power estimation for calculating a noise power estimation value from the replica generation channel estimation value calculated by the replica generation channel estimation unit and the received signal and the reference signal included in the small time interval And a multi-carrier signal receiver.

  The multicarrier signal receiver according to the third aspect of the present invention uses a pilot channel included in the first time interval to calculate a demodulation channel estimation value from a received signal and a reference signal. Propagation for replica creation that calculates a channel estimation value for replica creation from the received signal and the reference signal by using an estimation unit and pilot channels included in a plurality of small time intervals in the first time interval. A plurality of small times based on the received signal and the reference signal included in the plurality of small time intervals, and the replica creating channel estimation values calculated by the replica estimating channel estimating unit; A multi-carrier having a noise power estimation unit that calculates a noise power estimation value by calculating a noise power component at each interval and calculating an average of the noise power component Is the No. receiver.

Further, in the multicarrier signal receiver according to the first aspect of the present invention, the noise power estimation unit determines the range of the received signal and the reference signal located near the intermediate point depending on a fluctuation speed of a propagation path. Alternatively, the estimated noise power value may be calculated.
In the multicarrier signal receiver according to the second or third aspect of the present invention, the replica creation propagation path estimation unit and the noise power estimation unit may change the range of each small time interval to a propagation path fluctuation speed. Alternatively, the replica creation propagation path estimation value and the noise power estimation value may be calculated.
In the multicarrier signal receiver according to the first to third aspects of the present invention, the first time interval may be a time interval of one frame.

  Also, in the multicarrier signal reception method according to the first aspect of the present invention, the propagation path estimation unit calculates the propagation path estimation value from the received signal and the reference signal using the pilot channel included in the first time interval. Of the signal included in the first time interval and the propagation path estimated value calculated in the first step by the noise power estimator and the vicinity of the intermediate point of the first time interval And a second step of calculating a noise power estimation value from the received signal and the reference signal.

  Also, in the multicarrier signal reception method according to the second aspect of the present invention, the demodulation channel estimation unit estimates the demodulation channel from the received signal and the reference signal using the pilot channel included in the first time interval. A replica is created from the received signal and the reference signal by using a pilot channel included in a small time interval in the first time interval by a first step of calculating a value and a replica creation propagation path estimation unit A second step of calculating a propagation path estimation value, a noise power estimation unit, the replica generation propagation path estimation value calculated in the second step, and the received signal included in the small time interval; And a third step of calculating a noise power estimation value from the reference signal.

  Also, in the multicarrier signal reception method according to the third aspect of the present invention, the demodulation channel estimation unit estimates the demodulation channel from the received signal and the reference signal using the pilot channel included in the first time interval. A first step of calculating a value and a replica creation propagation path estimator, using pilot channels included in a plurality of small time intervals in the first time interval, from the received signal and the reference signal The replica creation propagation path estimation value is included in the second step of calculating the replica creation propagation path estimation value, and the noise power estimation unit includes the replica creation propagation path estimation value calculated in the second step, and the plurality of small time intervals. A noise power component is obtained for each of the plurality of small time intervals from the received signal and the reference signal, and an average of the noise power component is obtained to calculate a noise power estimated value. It is a multicarrier signal receiving method characterized by having a step.

In the multicarrier signal receiving method according to the first aspect of the present invention, in the second step, the range of the received signal and the reference signal located in the vicinity of the intermediate point depends on a fluctuation speed of a propagation path. Alternatively, the estimated noise power value may be calculated.
Further, in the multicarrier signal receiving method according to the second or third aspect of the present invention, in the second step and the third step, the range of each small time interval depends on the fluctuation speed of the propagation path. Alternatively, the replica creation propagation path estimation value and the noise power estimation value may be calculated.
In the multicarrier signal receiving method according to the first to third aspects of the present invention, the first time interval may be a time interval of one frame.

  According to the present invention, in a multicarrier signal receiver, noise power can be accurately obtained, so that appropriate weighting can be performed and an increase in maximum throughput can be realized.

It is a figure which expand | deploys and shows the structure of the flame | frame received by a multicarrier signal receiver in the three-axis directions of time, a frequency, and a code | cord | chord. It is a figure which shows the structure of the flame | frame received by a multicarrier signal receiver in detail in a time-axis direction. It is a block diagram which shows the basic composition of a multicarrier signal receiver. It is a block diagram which shows the structure of a baseband signal processing part. It is a block diagram which shows the structure of the channel estimation part in 1st Embodiment. It is a block diagram which shows the structure of the propagation path estimation part in 1st Embodiment. It is a block diagram which shows the structure of the noise power estimation part in 1st Embodiment. It is a figure for demonstrating the effect of 1st Embodiment. It is a figure for demonstrating the effect of 1st Embodiment. It is a figure which shows the structure of the flame | frame received by the multicarrier signal receiver in the modification of 1st Embodiment in detail in a time-axis direction. It is a figure which shows the structure of the flame | frame received by the multicarrier signal receiver in 2nd Embodiment in detail in a time-axis direction. It is a block diagram which shows the structure of the channel estimation part in 2nd Embodiment. It is a figure which shows the structure of the flame | frame received by the multicarrier signal receiver in the modification of 2nd Embodiment in detail in a time-axis direction. It is a figure which shows the structure of the flame | frame received by the multicarrier signal receiver in 3rd Embodiment in detail in a time-axis direction. It is a block diagram which shows the structure of the channel estimation part in 3rd Embodiment. It is a block diagram which shows the structure of the propagation path estimation part for replica production in 3rd Embodiment. It is a block diagram which shows the structure of the noise power estimation part in 3rd Embodiment. It is a figure.

Explanation of symbols

14, 14a ... channel estimation unit,
16, 16a ... demodulation channel estimation unit,
17, 17a ... noise power estimation unit,
18, 18a ... code multiplexing number estimation unit,
19, 19a ... propagation path estimation unit for replica creation,
171a, 171b ... signal selection unit,
172a, 172b ... averaging unit,
191 ... Signal selection unit,
192c-1 to 192c-3 ... averaging unit,
31 ... Signal selection unit,
32-33 ... multiplier,
34: Averaging unit,
41, 42... Multiplier
43 ... subtractor,
44 ... squarer,
221, 222... Multiplier
301 ... antenna part,
302 ... Radio frequency converter,
303 ... Baseband signal processing unit,
304: Media access control unit,
305... A / D converter,
306: Filter unit,
307 ... GI removal unit,
308: Fast Fourier transform unit,
309 ... despreading part,
310 ... weighting unit,
311 ... Adder,
312 ... P / S converter,
313: Decoder unit,
314 ... Channel estimation unit,
315 ... Weighting coefficient calculation unit,
316 ... propagation path estimation unit,
317: Noise power estimation unit,
318: Code multiplex number estimation unit

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of a frame received by a multicarrier signal receiver. In the figure, pilot channel PICH for channel estimation is time-multiplexed before and after one frame and in the vicinity of the middle (that is, PICH (1) of the first symbol, 26th symbol, 27th symbol, 52nd symbol) PICH (26), PICH (27), and PICH (52)), and a data traffic channel DTCH for transmitting data exists between them (that is, DTCH (2) to 2-25th symbol, 28th to 51st symbol) DTCH (25), DTCH (28) to DTCH (51)). This point is shown in the time axis direction of FIG. A plurality of subcarriers are arranged in the frequency axis direction. A plurality of data traffic channels DTCH are transmitted at the same frequency and the same time using different orthogonal codes. This point is shown in the code axis direction orthogonal to the time axis direction and the frequency axis direction.

FIG. 2 shows the frame configuration of FIG. As described above, using all the pilot channels PICH (that is, PICH (1), PICH (26), PICH (27), and PICH (52)) included in one frame including the first time interval t1, deriving a channel estimation value _{h m,} also, the time interval which is located near the midpoint of the time interval t1 t'1, i.e., a pilot channel PICH (i.e., PICH (26), PICH ( 27)) using the noise A power estimation value N is derived. In the present specification, the vicinity of the intermediate point refers to a small time interval including the intermediate point of the first time interval t1. The small time interval is a time in a frame and is a time interval that is small enough to ignore a channel fluctuation component during the time. For example, when the length of one frame corresponds to 52 symbols, the length is about 2 to 10 symbols.

FIG. 3 is a block diagram showing a schematic configuration of the multicarrier signal receiver. This multicarrier signal receiver includes an antenna unit 301, a radio frequency conversion unit 302, a baseband signal processing unit 303, and a media access control unit 304. The radio frequency conversion unit 302 performs frequency conversion of the signal input from the antenna unit 301 to the radio frequency conversion unit 302, and the baseband signal processing unit 303 performs the baseband signal output from the radio frequency conversion unit 302. Received signal data is extracted by performing a numerical calculation process. The media access control unit 304 can determine whether the received signal data extracted from the baseband signal processing unit 303 is a control channel or transmission data such as an audio signal, and can receive an appropriate signal. The transmission data is transferred to the upper layer.
FIG. 4 is a block diagram illustrating a configuration of the baseband signal processing unit 303 in FIG. An A / D (Analog / Digital) conversion unit 305 converts the reception signal output from the radio frequency conversion unit 302 (FIG. 2) into a digital signal. The filter unit 306 extracts only a signal in a desired band from the signal output from the A / D (Analog / Digital) conversion unit 305. A GI (Guard Interval) removing unit 307 removes GI from the signal output from the filter unit 306. A fast Fourier transform (FFT) unit 308 performs frequency conversion on the signal output from the GI removal unit 307 and demultiplexes and extracts the signal component y _m (i) of each subcarrier. Despreading section 309, the signal output from the fast Fourier transform unit 308 performs the multiplication of spreading codes s _m for each subcarrier. The weighting unit 310 multiplies the signal output from the despreading unit 309 by a weighting coefficient w _m for each subcarrier. Adder 311 adds the signals output from weighting section 310 for each subcarrier. A P / S (Parallel / Serial) conversion unit 312 performs parallel-serial conversion on the signal output from the addition unit 311. The decoder unit 313 performs demodulation and error correction decoding on the signal output from the P / S conversion unit 312 and outputs demodulated data.
Further, the channel estimation unit 314 uses the output y _m (i) of the fast Fourier transform unit 308 and the reference signal d _m (i) to estimate the propagation path estimation value h _m , noise power estimation value N, and code multiplexing number C _mux. Estimate The weighting coefficient calculation unit 315 calculates the weighting coefficient w _m based on the information _{hm ,} N, and C _mux output from the channel estimation unit 314 and outputs the weighting coefficient w _m to the weighting unit 310.
As an example, the weighting coefficient w _m is expressed by the following equation.
w _m = h _m ^* / (C _mux · h _m ² + N)
The subscript m (m is a positive integer) is a subcarrier number, and i is a symbol number of a received frame. Therefore, for example, y _m (i) indicates the received signal of the m-th subcarrier in the i-th symbol in the received frame. The superscript * indicates conjugate.

FIG. 5 is a block diagram showing the configuration of channel estimation section 314 (FIG. 4). The channel estimation unit 314 includes a propagation path estimation unit 316, a noise power estimation unit 317, and a code multiplexing number estimation unit 318. Channel estimation unit 316 obtains a channel estimation value _{h m} by using a reference signal _d m (i) and the received signal _y m (i). Reference signal d _m (i) indicates a known pilot channel PICH symbol before multiplication by the i-th scrambling code _cm in the frame and the m-th subcarrier. The noise power estimation unit 317 obtains the noise power estimation value N using the channel estimation value h _m , the reference signal d _m (i), and the reception signal y _m (i) output from the channel estimation unit 316. Also, the code multiplex number estimation unit 318 estimates the code multiplex number C _mux using the noise power estimation value N and the received signal y _m (i). The code multiplexing number C _mux may be notified from the transmitter using a control signal without being estimated by the code multiplexing number estimating unit 318.

FIG. 6 is a block diagram showing a configuration of the propagation path estimation unit 316 (FIG. 5). The propagation path estimation unit 316 includes a signal selection unit 31, multipliers 32 and 33, and an averaging unit 34. Signal selecting section 31, the received signal _y m (i) and the reference signal _d from the m _d ^m * is the conjugate of (i) (i), 1,26,27,52-th symbol corresponding to the entire pilot channel PICH Take out only. Therefore, d _m ^* (i) that is a conjugate of the reference signal d _m (i), which is a known sequence, is input to the signal selection unit 31, and only a signal corresponding to the PICH is output to the multiplier 32. Here, all of the reference signal _{d m (1), d m} (26), d m (27), d m conjugation _d ^m of ^{_{(52) * (1),}} d m * (26), d m * ( ^{_{27), d m * (52}} ) is outputted to the multiplier 32. The multiplier 32 multiplies the signal output from the signal selection unit 31 and _cm ^* that is a conjugate of the scrambling code _cm . In addition, the signal selection unit 31, the received signal _y m (i) is input, a signal corresponding to the pilot channel PICH in the received signal _y m (i) is outputted to the multiplier 33.
That is, for the multiplier 33 from the signal selection unit 31, the received signal _{y m (1), y m} (26), y m (27), signals y m (52) is outputted. Therefore, signals of c _m ^* · d _m ^* (i) · y _m (i) are output from the multiplier 33 to the averaging unit 34.
In the averaging unit 34, an average value is obtained and output as a propagation channel estimated value h _m = Σc _m ^* · d _m ^* (i) · y _m (i) / Np. Here, four symbols are averaged for each subcarrier, and therefore Np = 4. Therefore, channel estimation value _{h m (h m = (h} m (1) -h m (26) + h m (27) + h m (52)) / 4) is obtained.

FIG. 7 is a block diagram showing the configuration of the noise power estimation unit 317 (FIG. 5). The noise power estimation unit 317 includes a signal selection unit 171a, multipliers 41 and 42, a subtracter 43, a squarer 44, and an averaging unit 172a. The signal selection unit 171a extracts only the 26th and 27th symbols located in the vicinity of the midpoint of the pilot channel PICH from the received signal y _m (i) and the reference signal d _m (i). Therefore, the reference signal d _m (i), which is a known sequence, is input to the signal selection unit 171a, and only the signal corresponding to the PICH located near the midpoint of the frame is output to the multiplier 41. Here, the reference signals d _m (26) and d _m (27) are output from the signal selection unit 171a to the multiplier 41.
The multiplier 41 multiplies the above-mentioned signal output from the signal selection unit 171a by the scrambling code _cm . The multiplier 42 generates a replica signal by multiplying the signal output from the multiplier 41, the channel estimation value h _m estimated by the channel estimation unit 316. This replica signal indicates an ideal received signal to be received in a noise-free propagation state.
The subtractor 43 uses the replica signal output from the multiplier 42 from the signal corresponding to the pilot channel PICH located near the midpoint of the frame in the received signal y _m (i) output from the signal selection unit 171a. subtraction _to, calculates the _{y m (i) -h m ·} c m · d m (i). Here, y _m (26) and y _m (27) are output from the signal selection unit 171a to the subtractor 43.
The squarer 44 squares the signal output from the subtracter 43 and outputs a signal (y _m (i) −h _m · c _m · d _m (i)) ² to the averaging unit 172a. Averager 172a obtains the signal output from squarer 44 for each subcarrier, and then multiplies the number of PICH symbols (2 in FIG. 7) selected by signal selector 171a by the number of subcarriers Nc. in calculating the noise power per subcarrier by averaging, the noise power estimate _{N = Σ (y m (i} ) -h m · c m · d m (i)) output as 2 / (2Nc) To do.

In this way, the PICH corresponding to the positions before and after the frame (that is, the PICH of the first symbol and the 52nd symbol) is not used, and the PICH (that is, the 26th and 27th symbols) located near the midpoint of the frame is used. By estimating the noise power using PICH), the noise power can be estimated more accurately, and the weighting coefficient w _m used at the time of demodulation can be accurately obtained.
8A and 8B are diagrams for schematically explaining the operational effects of the present embodiment. 8A and 8B, the horizontal axis (I axis) represents the signal intensity of the received signal modulated by the cosine wave, and the vertical axis (Q axis) represents the signal intensity modulated by the sine wave. In addition, the signal power of the data traffic channel DTCH is shown superimposed on the corresponding signal strength position by a circle indicated by a dotted line. Besides this, the reception signal of the pilot channel PICH _(y m _(i)) is indicated by + signs indicates the replica signal of the pilot channel _{PICH (h m · c m ·} d m (i)) in × symbol. To determine the channel estimation value h _m more accurately, the PICH, since allocated a larger transmission power than the DTCH, in FIG., The + symbol, the position of the × symbol, the origin than dotted circles Located further away from Further, as shown in the figure, when the PICH corresponding to the positions before and after the frame (that is, the PICH of the first symbol and the 52nd symbol) is used (see FIG. 8A), the channel fluctuation component is expanded. There is a drawback that a noise power estimation value N that is apparently larger than the original noise power is obtained. On the other hand, when the PICH located near the midpoint of the frame (that is, the 26th and 27th symbol PICH) is used (see FIG. 8B), the channel fluctuation component is hardly included, and the noise power is small. For the most part, the noise power estimation value N is accurately obtained.

As a result, when the multicarrier signal receiver according to the present embodiment is used, the PICH power can be increased due to the fact that it can cope with the time variation of the propagation path as compared with the conventional method. It becomes possible to calculate the correct weighting coefficient w _m , and as expected, an increase in the maximum transmission rate (maximum throughput) can be realized. Note that to increase the power of the pilot channel PICH As mentioned previously, effectively act in determining the propagation channel estimation value h _m correctly.

(Modification of the first embodiment)
Then, the signal of the frame structure shown in FIG. 2 is subsequently received two frames are shown for the case of obtaining the channel estimation value h _m using the pilot channel PICH contained in the two frames.
FIG. 9 is a diagram showing a frame configuration in the above case. Here, as shown in FIG. 9, using all of the pilot channel PICH contained in the two frames made of the first time interval t2, to derive the channel estimation value h _m, also, the midpoint of the time interval t2 The case where the noise power estimation value N is derived using the small time interval t′2 located in the vicinity, that is, the PICH (that is, PICH (1, 52), PICH (2, 1)) will be described. Note that PICH (i, j) in the figure indicates the pilot channel of the jth symbol of the i frame. In the following _description, h m (i, j) is the channel estimation value _h m of the m-th subcarrier derived from the j th symbol of the i th _frame, d m (i, j) is i-th frame The reference signal of the m-th subcarrier in the j-th symbol, d _m ^* (i, j) is the conjugate of the reference signal d _m (i, j), and y _m (i, j) is the j-th symbol in the i frame. The received signal of the mth subcarrier in FIG.
The configuration of the receiver of this modification is the same as that of FIGS. 3 and 4, and includes the antenna unit, radio frequency conversion unit, baseband signal processing unit, media access control unit and their interconnections shown in FIG.

  Further, the configuration of the baseband signal processing unit of this modification is the same as that of FIG. 4, and the A / D conversion unit, filter unit, GI removal unit, fast Fourier transform unit, despreading unit, weighting unit shown in FIG. An adder, a P / S converter, a decoder, a channel estimator, a weighting coefficient calculator, and their interconnections.

  Next, the configuration of the channel estimator is the same as that shown in FIG. 5, and includes the channel estimator, noise power estimator, code multiplex number estimator and their interconnections shown in FIG.

The configuration of the propagation path estimation unit is the same as that in FIG. 6, and includes the signal selection unit, two multipliers, an averaging unit, and their interconnections shown in FIG. 6. However, for the reference signal d _m (i), the signal selection unit conjugates all reference signals d _m ^* (1,1), d _m ^* (1,26), d _m ^* (1,27), ^{_{d m * (1,52), d}} m * (2,1), d m * (2,26), d m * (2,27), and outputs the d m * (2,52). Further, the signal selection unit, the received signal _y m (i), the signal of all of the pilot channel _{y m (1,1), y m} (1,26), y m (1,27), y m ( _{1,52), y m (2,1)} , y m (2,26), y m (2,27), and outputs a y m (2,52). Therefore, the averaging unit calculates the average of the propagation path estimated values for the symbols corresponding to all pilot channels for 8 symbols as the propagation path estimated value h _m (h _m = Σc _m ^* d _m ^* (i) y _m ( i) Output as / N _p ). That is, N _p = 8.

The configuration of the noise power estimation unit is the same as that shown in FIG. 7, and includes a signal selection unit, two multipliers, a subtracter, a squarer, an averaging unit and their interconnections shown in FIG. However, for the reference signal d _m (i), the signal selection unit refers to the reference signals d _m (1,52), d _m (2,1) of the 52nd symbol of the first frame and the first symbol of the second frame. ) Is output. Further, the signal selection unit receives the received signals y _m (1,52) and y _m (2,1) of the 52nd symbol of the first frame and the first symbol of the second frame for the received signal y _m (i). ) Is output. Therefore, the averaging unit obtains the square of the difference between the received signal and the replica signal for each subcarrier, and then averages the value by multiplying the number of PICH symbols (2 in this modification) and the number of subcarriers Nc. 1 per subcarrier noise power _{N (N = Σ (y m} (i) -h m · c m · d m (i)) 2 / (2N c)) to output a.

In this way, PICH other than the PICH located near the midpoint of the two frames is not used, and the PICH located near the midpoint of the two frames (that is, the 52nd symbol of the first frame and the first symbol of the second frame) Is used to estimate the noise power estimation value N, so that the noise power can be estimated more accurately, and the weighting coefficient w _m used at the time of demodulation can be accurately obtained.

  In the above description, two consecutive frames have been described as an example. However, in this case, the same processing as described above can be performed in consecutive n frames (n is an integer of 2 or more).

  In the above description, the noise power estimation value N is obtained using two consecutive symbols of PICH. However, when the channel fluctuation is small, the noise power estimation value N is calculated using more PICHs. Since the noise power estimated value N can be obtained more accurately by obtaining, the range of the pilot channel PICH for obtaining the noise power estimated value N may be changed depending on the fluctuation speed of the propagation path.

  Further, by comparing the noise power estimation value N obtained using the conventional method and the noise power estimation value N obtained using the method of the present embodiment, if the difference between these is large, it is determined that the channel fluctuation is fast. For example, the speed of channel fluctuation may be estimated.

In the embodiment described above, the noise power estimate N, the plurality of pilot channels to be used for calculating the channel estimation value h _m case has been described are continuous, but is not limited thereto . If a pilot channel located near the midpoint of the frame is used, a plurality of discontinuous pilot channels can be used.

(Second Embodiment)
FIG. 10 is a diagram illustrating a configuration of a frame received by the multicarrier signal receiver according to the second embodiment of the present invention. Here, using all of the pilot channel PICH contained in one frame consisting of a first time interval t1, to derive a channel estimation value h _m demodulation, also small time interval t in the time interval t1 ' A case where the replica creation propagation path estimation value h _m ′ and the noise power estimation value N are derived using the continuous pilot channels PICH (for example, PICH (1), PICH (2)) included in FIG. The small time interval is the same as that described above in the description of the first embodiment.

  The configuration of the CDMA multi-carrier signal receiver of this embodiment is the same as that of FIG. 3, and the antenna unit, radio frequency conversion unit, baseband signal processing unit, media access control unit shown in FIG. Have

  Further, the configuration of the baseband signal processing unit of this embodiment is the same as that of FIG. 4, and the A / D conversion unit, filter unit, GI removal unit, fast Fourier transform unit, despreading unit, weighting unit shown in FIG. An adder, a P / S converter, a decoder, a channel estimator, a weighting coefficient calculator, and their interconnections.

However, the channel estimation unit of the present embodiment has a configuration different from that of the first embodiment, and this is shown in a block diagram as a channel estimation unit 14 in FIG. The channel estimation unit 14 includes a demodulation channel estimation unit 16, a noise power estimation unit 17, a replica creation channel estimation unit 19, and a code multiplexing number estimation unit 18. The demodulation channel estimator 16 uses the reference signal d _m (i) and the received signal y _m (i) related to all pilot channels included in one frame having the first time interval t1 to estimate the demodulation channel. obtaining a value h _m (this demodulation channel estimation value h _m is delivered directly to the weighting coefficient calculating unit (weighting coefficient calculating unit 315 of FIG. 4).). The replica creation channel estimation unit 19 obtains a replica creation channel estimation value h _m ′ by using a part of the reference signal d _m (i) and the received signal y _m (i) in the frame. Here, d _m (1), d _m (2), y _m (1), and y _m (2) corresponding to the first symbol and the second symbol are input to the replica creation propagation path estimation unit 19. The
The noise power estimation unit 17 uses the replica generation channel estimation value h _m ′ output from the replica generation channel estimation unit 19, the reference signal d _m (i), and the received signal y _m (i) to generate noise. The power estimated value N is obtained. The code multiplex number estimation unit 18 estimates the code multiplex number C _mux using the noise power estimation value N output from the noise power estimation unit 17 and the received signal y _m (i).
Incidentally, the demodulation channel estimation unit 16, noise power estimation unit 17, the replica creation channel estimator 19, each channel estimation value h _m and noise for demodulation using the signal of the corresponding symbol PICH in the frame The power estimation value N and the replica creation propagation path estimation value h _m ′ are obtained. The code multiplexing number C _mux may be notified from the transmitter using a control signal.

Next, the configuration of the demodulation channel estimation unit 16 will be described in detail. The configuration of the demodulation channel estimation unit 16 is the same as that of the channel estimation unit 316 (see FIG. 6) according to the first embodiment. The signal selection unit, two multipliers, and the averaging unit shown in FIG. Interconnects. However, for the reference signal d _m (i), the signal selection unit d _m ^* (1), d _m ^* (2), d _m ^* (27), d _m ^* ( ^{_{28), d m * (53}} ), and outputs the ^d m * (54). Further, the signal selection unit, the received signal _y m (i), the signal _y m of all pilot channels _{(1), y m (2} ), y m (27), y m (28), y m ( 53) and y _m (54) are output. Therefore, the averaging unit calculates the average of the propagation path estimation values for the symbols corresponding to all pilot channels for 6 symbols as the propagation path estimation value h _m (h _m = Σc _m ^* d _m ^* (i) y _m ( i) Output as / N _p ).

The configuration of the replica creation propagation path estimation unit 19 (FIG. 11) will be described. The configuration of the replica creation propagation path estimation unit 19 is the same as the propagation path estimation unit 316 (see FIG. 6) according to the first embodiment, and includes a signal selection unit, two multipliers, an averaging unit illustrated in FIG. With its interconnection. However, the signal selecting unit, for the reference signal _d m (i), from the _d ^m * is the conjugate of the reference signal is a known sequence _{d m (i) (i)} , d m * (1), d m ^* Output only (2). Further, the signal selection unit outputs only the signals y _m (1) and y _m (2) corresponding to the PICH in the received signal y _m (i) for the received signal y _m (i). Accordingly, the averaging unit outputs the signal that the channel estimation value ^{_{h m '= Σc m * ·}} d m * (i) · y m (i) / 2. That is, two symbols are averaged for each subcarrier, and a replica creation propagation path estimation value h _m ′ = (h _m ′ (1) + h _m ′ (2)) / 2 is obtained.

The configuration of the noise power estimation unit 17 is the same as that in FIG. 7, and includes a signal selection unit, two multipliers, a subtracter, a squarer, an averaging unit and their interconnections shown in FIG. However, the signal selecting unit, for the reference signal _d m (i), from the reference signal is a known sequence _d m (i), the signal _{d m} corresponding to the first symbol and the second symbol of the pilot channel PICH frame (1) and d _m (2) are output. Further, the signal selection unit outputs signals y _m (1) and y _m (2) corresponding to the pilot channel PICH included in the first symbol and the second symbol of the frame for the received signal y _m (i). . Therefore, the averaging unit obtains the square of the difference between the received signal and the replica signal for each subcarrier, and then averages the value by multiplying the number of PICH symbols (2 in this embodiment) and the number of subcarriers Nc. 1 outputs a per subcarrier noise power _{N (N = Σ (y m} (i) -h m '· c m · d m (i)) 2 / (2N c)).

In this way, the pilot channel PICH included in a part of the frame (that is, the PICH of the first symbol and the second symbol) is used to estimate the propagation path estimation value h _m ′ for replica creation and the noise power estimation value N. By doing so, it is possible to estimate the noise power more accurately, and to accurately determine the weighting coefficient w _m used at the time of demodulation.
That is, as in the prior art, obtains a propagation path estimated value h _m from the pilot channel PICH of the entire frame, when estimating the noise power from the PICH for the entire frame, small variations of the propagation path affect the noise power estimation However, as in this embodiment, the PICH included in a part of the frame (that is, the PICH of the first symbol and the second symbol) is used to create a replica. When the propagation path estimation value h _m ′ and the noise power estimation value N are obtained, the channel fluctuation component is hardly included, and the noise power becomes most. Further, as the weighting factor w _m = h _m ^* / (C _mux · h _m ² + N) h _m and its conjugate h _m ^* , the demodulation channel coefficient h _m as an average value for all the above-described pilot channels. And its conjugate h _m ^* , the weighting coefficient w _m can be obtained more accurately.

As a result, when the multicarrier signal receiver according to the present embodiment is used, it is more resistant to time fluctuations of the propagation path than that according to the prior art, and is correct even if the power of the pilot channel PICH is increased. w _m can be calculated. Note that to increase the power of the PICH as described previously, effectively act in determining the propagation channel estimation value h _m correctly.

(Modification of the second embodiment)
Then, the signal of the frame structure shown in FIG. 10 described above are subsequently received two frames, a case of obtaining the channel estimation value h _m for demodulation using the PICH contained in two frames.
FIG. 12 is a diagram illustrating a configuration of a frame received by the multicarrier signal receiver according to the present modification. Here, as shown in FIG, using all PICH contained in the two frames made of the first time interval t2, to derive the channel estimation value h _m demodulation, also small in the time interval t2 For creating a replica using a continuous pilot channel PICH (for example, PICH (1, 53), PICH (1, 54), PICH (2, 1), PICH (2, 2))) included in the time interval t′3 A case where the channel estimation value h _m ′ and the noise power estimation value N are derived will be described.

  The configuration of the CDMA multi-carrier signal receiver of this modification is the same as that of FIG. 3, and the antenna unit, radio frequency conversion unit, baseband signal processing unit, media access control unit shown in FIG. Have

  Further, the configuration of the baseband signal processing unit of this embodiment is the same as that of FIG. 4, and the A / D conversion unit, filter unit, GI removal unit, fast Fourier transform unit, despreading unit, weighting unit shown in FIG. An adder, a P / S converter, a decoder, a channel estimator, a weighting coefficient calculator, and their interconnections.

  The configuration of the channel estimation unit is the same as that in FIG. 11, and includes the demodulation channel estimation unit, replica creation channel estimation unit, noise power estimation unit, code multiplex number estimation unit and their interconnections shown in FIG. . However, the following points are different.

First, the configuration of the demodulation channel estimation unit is the same as that of FIG. 6 and includes the signal selection unit, two multipliers, an averaging unit and their interconnections shown in FIG. for the reference signal _d m (i), all the reference signal _{d m (1,1), d m} (1,2), d m (1,27), d m (1,28), d m ( _{1,53), d m (1,54)} , d m (2,1), d m (2,2), d m (2,27), d m (2,28), d m (2, 53) and conjugate of d _m (2,54) are output. Further, the signal selection unit, for the received signal y _m (i), y _m (1,1), y _m (1,2), y _m (1,27), y _m (1) of all pilot channels. _{, 28), y m (1,53} ), y m (1,54), y m (2,1), y m (2,2), y m (2,27), y m (2,28 ), Y _m (2,53), y _m (2,54) are output. Therefore, the averaging unit calculates an average of 12 symbols of propagation path estimation values for symbols corresponding to all pilot channels as a propagation path estimation value h _m (h _m = Σc _m ^* d _m ^* (i) y _m ( i) Output as / N _p ). However, N _p = 12.

The configuration of the replica creation propagation path estimator is the same as that of the propagation path estimator 316 (see FIG. 6) according to the first embodiment. The signal selector, two multipliers, and the averaging section shown in FIG. has an interconnect, however, the signal selecting unit, for the reference signal _d m (i), from the _d ^m * (i) is the conjugate of the reference signal is a known sequence _{d m} (i), _d m ^{_{* (1,53), d m *}} (1,54), d m * (2,1), and it outputs the d m * (2,2). Further, the signal selection unit, the received signal _y m (i) is the received signal _y m signal corresponds to PICH of _{(i) y m (1,53)} , y m (1,54), y m ( 2, 1) and y _m (2, 2) are output. Therefore, the averaging unit outputs a signal of propagation path estimation value h _m ′ = Σc _m ^* · d _m ^* (i) · y _m (i) / 4. That is, four symbols are averaged for each frame, and the propagation path estimated value h _m ′ = (h _m ′ (1,53) + h _m ′ (1,54) + h _m ′ (2,1) + h _m ′ (2 , 2)) / 4.

The configuration of the noise power estimator is the same as that shown in FIG. 7 and includes the signal selector shown in FIG. 7, two multipliers, a subtracter, a squarer, an averager, and their interconnections. parts are, for the reference signal d _{m (i),} from the reference signal is a known sequence d _{m (i),} 1 frame of 53 th symbol and 54 th symbol, the first symbol of the second frame and the second symbol The signals d _m (1,53), d _m (1,54), d _m (2,1), d _m (2,2) corresponding to the pilot channel PICH are output. Further, the signal selection unit, for the received signal y _m (i), is a signal corresponding to the pilot channel PICH included in the 53rd and 54th symbols of the first frame and the 1st and 2nd symbols of the 2nd frame. y _m (1,53), y _m (1,54), y _m (2,1), y _m (2,2) are output. Therefore, the averaging unit obtains the square of the difference between the received signal and the replica signal for each subcarrier, and then averages the value by multiplying the number of PICH symbols (4 in this modification) by the number of subcarriers Nc. outputting a per subcarrier noise power _{N = Σ (y m (i} ) -h m '· c m · d m (i)) 2 / (4Nc).

In this way, using the PICH included in a part of the frame (that is, the 53rd and 54th symbols in the first frame and the 1st and 2nd symbol PICHs in the second frame), propagation for replica creation is performed. By estimating the path estimation value h _m ′ and the noise power estimation value N, more accurate noise power can be estimated, and the weighting coefficient w _m used at the time of demodulation can be accurately obtained.
Obtains channel estimation value h _m from the whole frame PICH as described in the prior art description, when estimating the noise power from the PICH for the entire frame, small variations in the propagation path effects on the noise power estimation However, the correct noise power could not be obtained, but the PICH (that is, the 53rd and 54th symbols of the first frame and the 1st of the second frame) matched to a part of the frame as in the present modification. When the replica creation propagation path estimation value h _m ′ and the noise power estimation value N are obtained using the symbolic and second symbol PICHs), the channel fluctuation component is hardly included, and the noise power is mostly It becomes.

As a result, when the multicarrier signal receiver of the present modification is used, the weighting factor w _m is calculated more accurately even when the power of the PICH is increased, because it is stronger against time fluctuations of the propagation path than the conventional technique. It becomes possible to do. Note that to increase the power of the PICH as described previously, effectively act in determining the propagation channel estimation value h _m correctly.

In the above description, the case of two consecutive frames has been described. However, the present invention is not limited to such a configuration, and can be applied to the case of consecutive n frames (n is an integer of 2 or more).
Further, as apparent from the second embodiment, the temporal position of the PICH for performing the replica creation propagation path estimation and the noise power estimation may be at any position in the frame. That is, it may be located at a small time interval near the leading edge of the frame, at a small time interval near the middle point of the frame, or at a small time interval near the trailing edge of the frame.

In the above-described embodiment, the replica creation propagation path estimation value h _m ′ and the noise power estimation value N are obtained using the continuous 2-symbol or 4-symbol pilot channel PICH, but the propagation path fluctuation is small. In this case, the replica creation channel estimation value h _m ′ is obtained more accurately (without being affected by noise) by obtaining the replica creation channel estimation value h _m ′ using more PICHs. Depending on the fluctuation speed of the propagation path, the PICH range for obtaining the replica creation propagation path estimation value h _m ′ and the noise power estimation value N can be changed.

In the above-described embodiment, a plurality of noise power estimation values N, demodulation channel estimation values h _m , demodulation channel estimation values h _m , and replica creation channel estimation values h _m ′ are used. However, the present invention is not limited to this, and a plurality of non-continuous pilot channels can be used.

(Third embodiment)
FIG. 13 is a diagram illustrating a frame configuration according to the third embodiment of the present invention. Here, using all PICH included in one frame consisting of a first time interval t1, to derive a channel estimation value h _m demodulation, also, a plurality of small time interval t in the time interval t1 ' 4, t′5 and t′6 include consecutive PICHs (eg, PICH (1) and PICH (2), PICH (27) and PICH (28), PICH (53) and PICH (54))), respectively. A case where the replica creation propagation path estimation values h _m ′, h _m ″, h _m ′ ″ and the noise power estimation value N are derived will be described. The small time interval is the same as that described above in the explanation of the first embodiment.

The configuration of the CDMA multi-carrier signal receiver of this embodiment is the same as that of FIG. 3, and the antenna unit, radio frequency conversion unit, baseband signal processing unit, media access control unit shown in FIG. Have
The configuration of the baseband signal processing unit of the CDMA multicarrier signal receiver of the present embodiment is the same as that of FIG. 4, and the A / D conversion unit, filter unit, GI removal unit, high speed shown in FIG. A Fourier transform unit, a despreading unit, a weighting unit, an addition unit, a P / S conversion unit, a decoder unit, a channel estimation unit, a weighting coefficient calculation unit and their interconnections

However, the channel estimation unit has the configuration shown in FIG. That is, FIG. 14 is a block diagram showing the configuration of the channel estimation unit 14a according to this embodiment. The channel estimation unit 14a includes a demodulation channel estimation unit 16a, a noise power estimation unit 17a, a replica creation channel estimation unit 19a, and a code multiplexing number estimation unit 18a. Demodulation channel estimation unit 16a obtains a channel estimation value _{h m} for demodulation using the reference signal _d m (i) and the received signal _y m (i). Replica creation channel estimator 19a, a part of the reference signal in the frame _d m (i) and the received signal _y m (i) replica creation propagation path estimated value from _{h m ', h m''} , h m '''Is obtained and output to the noise power estimation unit 17a. Here the propagation path estimation unit 19a for replica creation, the first symbol, 2 _d ^m * ₍₁₎ corresponding to th _symbol, ^{d m} * (2) and _y m _(1), and _y m (2), 27 th symbol, _d ^m * ₍₂₇₎ corresponding to the 28 th ^{symbol, d} m * (28) and _y m _(27), and y m (28), 53 th symbol, _d corresponds to the first 54 symbols ^{m * _{(53), d m * (}} 54) and _y m _{(53), y} m channel estimation value for the replica created using _{(54) h m ', h} m'', seek h _m'''.
Noise power estimation unit 17a, a replica creation propagation path estimated value determined by the replica creation channel estimation unit _{19a h m ', h m'} ', h m''', the reference signal _d m (i) and the received signal The noise power estimation value N is obtained using y _m (i). The code multiplex number estimation unit 18a estimates the code multiplex number C _mux using the noise power estimation value N and the received signal y _m (i).
Note that the demodulation channel estimation unit 16a and the noise power estimation unit 17a obtain the channel estimation value h _m and the noise power estimation value N using a signal of a symbol corresponding to the PICH in the frame.
The code multiplexing number C _mux may be notified from the transmitter using a control signal.

The configuration of the demodulation channel estimation unit 16a is the same as that in FIG. 6, and includes the signal selection unit, two multipliers, an averaging unit, and their interconnections shown in FIG. However, for the conjugate d _m ^* (i) of the reference signal, the signal selection unit conjugates d _m ^* (1), d _m ^* (2), d _m ^* (27), d _m ^{* of} all the reference signals ^{. _{(28), d m * (}} 53), and outputs the ^d m * (54). Further, the signal selection unit, the received signal _y m (i) is _y m ₍₁₎ for all of the pilot _{channel, y m (2), y} m (27), y m (28), y m (53 ), Y _m (54). Therefore, the averaging unit calculates the average of the propagation path estimated values for the symbols corresponding to all pilot channels for 6 symbols as the propagation path estimated value h _m = (h _m (1) + h _m (2) + h _m (27 ) + H _m (28) + h _m (53) + h _m (54)) / 6.

FIG. 15 is a block diagram illustrating a configuration of the replica creation propagation path estimation unit 19a according to the present embodiment. The replica creation propagation path estimation unit 19a includes a signal selection unit 191, multipliers 221, 222, and averaging units 192c-1, 192c-2, 192c-3. The signal selection unit 191 outputs only a signal corresponding to the PICH to the multiplier 221 from d _m ^* (i) which is a conjugate of the reference signal d _m (i) which is a known sequence. Here, with respect to the signal selecting unit 191 to the multiplier ^{_{221, d m * (1)}} , d m * (2), d m * (27), d m * (28), d m * (53), d _m ^* (54) is output. The multiplier 221 multiplies the signal output from the signal selection unit 191 by _cm ^* that is a conjugate of the scrambling code _cm .
Further, the signal selection unit 191 outputs a signal corresponding to the PICH among the reception signals y _m (i) to the multiplier 222. Here, with respect to the signal selecting unit 191 to the multiplier _{222, y m (1),} y m (2), y m (27), y m (28), y m (53), y m (54) Is output.
The multiplier 222 includes a signal output from the signal selection section 191 multiplies the signal output from the multiplier 221 _to calculate the ^{_{c m * · d m * (}} i) · y m (i). Among these c _m ^* · d _m ^* (i) · y _m (i), the signals i = 1 and 2 are output to the averaging unit 192c-1, and the signals i = 27 and 28 are output to the averaging unit 192c. -2, and i = 53 and 54 are output to the averaging unit 192c-3.
The averaging unit 192c-1 averages the signal output from the multiplier 222, and obtains the replica creation propagation path estimated value h _m ′ = Σc _m ^* · d _m ^* (i) · y _m (i) / 2. Output. However, i = 1,2.
The averaging unit 192c-2 averages the signal output from the multiplier 222, and the replica creation propagation path estimation value h _m ″ = Σc _m ^* · d _m ^* (i) · y _m (i). / 2 is output.
However, i = 27,28.
Further, the averaging unit 192c-3 averages the signal output from the multiplier 222, and the replica creation propagation path estimation value h _m ′ ″ = Σc _m ^* · d _m ^* (i) · y _m (i ) / 2 is output. However, i = 53, 54.

FIG. 16 is a block diagram showing the configuration of the noise power estimation unit 17a according to this embodiment. The noise power estimation unit 17a includes a signal selection unit 171b, multipliers 2311, 2312, 2321, 2322, 2331, 2332, subtractors 2313, 2323, 2333, squarers 2314, 2324, 2334, and an averaging unit 172b.
The signal selection unit 171b outputs only a signal corresponding to the PICH included in the first section t′4 of the frame to the multiplier 2311 from the reference signal d _m (i) that is a known sequence. Here, d _m (1) and d _m (2) are output from the signal selection unit 171b to the multiplier 2311.
The multiplier 2311 multiplies the signal output from the signal selection unit 171b by the scrambling code _cm . Multiplier 2312 to the signal output from the multiplier 2311, to create a replica signal by multiplying replica creation channel estimation value h _{m 'estimated} by the replica creation channel estimation unit 19a.
In addition, the signal selection unit 171b subtracts a signal (here, y _m (1), y _m (2)) corresponding to the PICH included in the first interval t′4 from the received signal y _m (i). 2313 is output. The subtracter 2313 subtracts the signal output from the multiplier 2312 from the signal output from the signal selection unit 171b, and squares the signal y _m (i) −h _m ′ · c _m · d _m (i). Output to the device 2314. Squarer 2314 squares the signal output from the subtractor _2313, and outputs the same to the averaging unit 172b a signal that _{(y m (i) -h m} '· c m · d m (i)) 2 .
The same processing as the processing in the first interval t′4 described above is performed in the second interval t′5 (reference signals d _m (27), d _m (28) and replica creation propagation path estimation value h _m ″. And reception signals y _m (27) and y _m (28) are used). In addition, the same processing as the processing in the first section described above is performed in the third section t′6 (reference signals d _m (53), d _m (54) and replica creation propagation path estimation value h _m ″ ″). And the received signals y _m (53) and y _m (54) are used).
The averaging unit 172b obtains the signals output from the squarers 2314, 2324, and 2334 for each subcarrier, and then sets the number of subcarriers Nc to the number of PICH symbols (6 in FIG. 16) selected by the signal selection unit 171b. A noise power estimation value N per subcarrier is calculated by averaging with the multiplied value.

In this way, by using the PICH included in a part of the frame, the replica creation propagation path estimation values h _m ′, h _m ″, h _m ′ ″ and the noise power estimation value N are obtained more accurately. Noise power can be estimated, and the weighting coefficient w _m used at the time of demodulation can be accurately obtained.

As a result, when the multicarrier signal receiver according to the present embodiment is used, the weighting factor w _m is increased even if the power of the PICH is increased, even if the power of the PICH is increased, as compared with the conventional technique. It is possible to calculate. Note that to increase the power of the PICH as described previously, effectively act in determining the propagation channel estimation value h _m correctly.
Furthermore, since the noise power estimation value N is obtained using a plurality of discrete PICHs as compared with the second embodiment, a more accurate value can be obtained and a correct weighting coefficient w _m can be calculated. This leads to improved characteristics.

In the above-described embodiment, the noise power estimation value N, the demodulation propagation path estimation value h _m , and the replica creation propagation path estimation values h _m ′, h _m ″, h _m ″ ″ are used. Although a case where a plurality of pilot channels are continuous has been described, the present invention is not limited to this.

  In the embodiment described above, a program for realizing functions such as a propagation path estimation unit, a noise power estimation unit, and a replica creation propagation path estimation unit is recorded on a computer-readable recording medium. The multi-carrier signal receiver may be controlled by causing the computer system to read and execute the program recorded on the computer. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system. Further, the “computer-readable recording medium” dynamically holds a program for a short time, like a communication line in the case of transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, it is also assumed that a server that holds a program for a certain time, such as a volatile memory inside a computer system that serves as a server or client. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope not departing from the gist of the present invention.

  The present invention relates to a multicarrier signal receiver and a multicarrier signal receiving method for receiving radio waves transmitted using a multicarrier system, and is applied to a mobile phone or the like. According to the present invention, in a multicarrier signal receiver, noise power can be accurately obtained, so that appropriate weighting can be performed and an increase in maximum throughput can be realized.

Claims (12)

A propagation path estimator that calculates a propagation path estimated value from a received signal and a reference signal using a pilot channel included in the first time interval;
Of the propagation path estimated value calculated by the propagation path estimation unit and the signal included in the first time interval, the received signal and the reference signal located near the midpoint of the first time interval A noise power estimation unit for calculating a noise power estimation value;
A multicarrier signal receiver comprising: A demodulation channel estimation unit that calculates a demodulation channel estimation value from the received signal and the reference signal using a pilot channel included in the first time interval;
A replica creation channel estimation unit that calculates a replica creation channel estimation value from the received signal and the reference signal using a pilot channel included in a small time interval in the first time interval;
A noise power estimation unit that calculates a noise power estimation value from the received signal and the reference signal included in the small time interval, and the replica generation channel estimation value calculated by the replica generation channel estimation unit; ,
A multicarrier signal receiver comprising: A demodulation channel estimation unit that calculates a demodulation channel estimation value from the received signal and the reference signal using a pilot channel included in the first time interval;
A replica creation channel estimation unit that calculates a replica creation channel estimation value from the received signal and the reference signal using pilot channels included in a plurality of small time intervals in the first time interval; ,
From the replica creation propagation path estimation value calculated by the replica creation propagation path estimation unit and the received signal and the reference signal included in the plurality of small time intervals, noise power is obtained for each of the plurality of small time intervals. A noise power estimation unit that calculates a noise power estimated value by calculating a component and calculating an average of the noise power component;
A multicarrier signal receiver comprising:   The noise power estimation unit calculates the noise power estimation value by changing a range of the reception signal and the reference signal located near the intermediate point depending on a fluctuation speed of a propagation path. Item 4. The multicarrier signal receiver according to Item 1.   The replica creation propagation path estimation unit and the noise power estimation unit change the range of each small time interval depending on the fluctuation speed of the propagation path, and the replica creation propagation path estimation value and the noise power estimation value. The multicarrier signal receiver according to claim 2, wherein the multicarrier signal receiver is calculated.   The multicarrier signal receiver according to any one of claims 1 to 3, wherein the first time interval is a time interval of one frame. A first step of calculating a channel estimation value from the received signal and the reference signal by using the pilot channel included in the first time interval by the channel estimating unit;
Of the signal included in the propagation path estimated value calculated in the first step and the first time interval by the noise power estimation unit, the reception is located near an intermediate point of the first time interval. A second step of calculating a noise power estimate from the signal and the reference signal;
A multicarrier signal reception method comprising: A first step of calculating a demodulation channel estimation value from the received signal and the reference signal by using the pilot channel included in the first time interval by the demodulation channel estimating unit;
A replica creation propagation path estimation unit calculates a replica creation propagation path estimation value from the received signal and the reference signal by using a pilot channel included in a small time interval in the first time interval. And the steps
A noise power estimation unit calculates a noise power estimated value from the replica creation propagation path estimated value calculated in the second step and the received signal and the reference signal included in the small time interval. And the steps
A multicarrier signal reception method comprising: A first step of calculating a demodulation channel estimation value from the received signal and the reference signal by using the pilot channel included in the first time interval by the demodulation channel estimating unit;
A replica creation propagation path estimation unit calculates a replica creation propagation path estimated value from the received signal and the reference signal using pilot channels included in a plurality of small time intervals in the first time interval. A second step;
By the noise power estimation unit, the replica creation propagation path estimated value calculated in the second step and the received signal and the reference signal included in the plurality of small time intervals, for each of the plurality of small time intervals. Determining a noise power component, and calculating a noise power estimate by calculating an average of the noise power component;
A multicarrier signal reception method comprising:   The noise power estimation value is calculated in the second step by changing a range of the received signal and the reference signal located near the intermediate point depending on a fluctuation speed of a propagation path. Item 8. The multicarrier signal reception method according to Item 7.   In the second step and the third step, the replica creation propagation path estimation value and the noise power estimation value are calculated by changing the range of each small time interval depending on the propagation speed of the propagation path. The multicarrier signal receiving method according to claim 8 or 9, wherein   The multicarrier signal reception method according to claim 7, wherein the first time interval is a time interval of one frame.

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