JP2005073162A - Receiving device and method for estimating amplitude ratio - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve receiving performance by estimating an amplitude ratio of a known signal to an information signal using channel estimation power for each path even if a path with a low receiving level because of fading exists. <P>SOLUTION: Finger parts 110-1 to 110-n obtain channel estimation power from a CPICH symbol (known signal) of each path and synchronously detects an HS-PDSCH symbol (information signal). A path determining part 120 determines a path to be used for amplitude ratio estimation of the known signal to the information signal using the channel estimation power. A rake synthesis part 130 rake-synthesizes the result of synchronous detection of the HS-PDSCH symbol. A fading removing part 140 divides the HS-PDSCH symbol of the path determined by the path determining part 120 by the channel estimation power of this path. An amplitude ratio levelling part 150 levels the absolute value of the division result over a predetermined interval and calculates the amplitude ratio. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus and an amplitude ratio estimation method, and in particular, modulation using a modulation scheme such as 16QAM (16 Quadrature Amplitude Modulation), which requires a transmission level ratio between a known signal and an information signal in order to demodulate a received signal. The present invention relates to a receiving apparatus and an amplitude ratio estimating method for receiving a received signal.

  In recent years, high-speed packet communication such as HSDPA (High Speed Downlink Packet Access) has attracted attention in the wireless communication field. In HSDPA, an adaptive modulation scheme is used for packet transmission from a base station apparatus in order to transmit packets at an optimal transmission rate in accordance with a downlink propagation environment. In the adaptive modulation scheme, a modulation scheme according to the propagation environment is adaptively selected, and the transmission rate is controlled.

  Modulation schemes used for the adaptive modulation scheme include QPSK (Quadrature Phase Shift Keying) and 16QAM. QPSK expresses 2-bit information with one symbol using only the phase component of the waveform, whereas 16QAM expresses 4-bit information with one symbol by putting information on the amplitude component of the waveform. Can do.

  In addition, demodulation of a signal modulated by 16QAM requires a reference signal point arrangement indicating signal point candidates on the IQ plane of symbols modulated by 16QAM. In order to generate this reference signal point constellation, a physical channel (ie, HS-PDSCH (High Speed Physical Downlink Shared CHannel) and CPICH (Common PIlot CHannel) used by the base station apparatus for transmission of information signals (packets) and known signals is used. )), Information on what amplitude ratio is used for transmission is used.

  However, in HSDPA, the amplitude ratio between the information signal and the known signal (hereinafter simply referred to as “amplitude ratio”) is not notified from the base station apparatus, so the mobile station apparatus estimates the amplitude ratio from the received signal, and 16QAM Needs to be generated.

  Hereinafter, an example of a method for estimating the amplitude ratio between HS-PDSCH and CPICH will be described with reference to the description of Non-Patent Document 1, for example.

  Non-Patent Document 1 describes a method for estimating the amplitude ratio described above using a Rake-combined HS-PDSCH signal and channel estimation power obtained from the CPICH signal. In this method, the amplitude ratio is estimated by an apparatus as shown in FIG.

  Specifically, first, channel estimation is performed on the CPICH signal by the channel estimation unit 10, and the obtained channel estimation value is output to the complex conjugate calculation unit 20 and the multiplier 30. Then, the complex conjugate of the channel estimation value is calculated by the complex conjugate calculation unit 20, and the channel estimation value is multiplied by the complex conjugate by the multiplier 30, whereby the channel estimation power is obtained. This channel estimated power is obtained for each finger, and the channel estimated power for each finger is added by the channel estimated power adding unit 50.

  On the other hand, the HS-PDSCH signal is synchronously detected by the synchronous detection unit 40 using the complex conjugate of the channel estimation value. The synchronous detection of the HS-PDSCH signal is performed for each finger, and the result of synchronous detection for each finger is Rake combined by the Rake combining unit 60.

Then, the fading removal unit 70 divides the Rake-combined symbol by the sum value of the channel estimation power, and as a result, the amplitude fluctuation of the HS-PDSCH signal due to fading is removed, and the CPICH signal and the HS-PDSCH signal are transmitted. The amplitude ratio of time is estimated.
3GPP, R1-01-0921 "A Method for Blind Determination of Pilot to Data Power Ratio for QAM Signals", TSG-RAN Working Group 1 meeting # 21 Italy, 27th-31stAugust 2001

  However, since the reception levels of the paths corresponding to the fingers vary with time due to fading, the reception levels of all paths are not necessarily high enough. For a path with a low reception level, the accuracy of channel estimation decreases, and the error included in the channel estimation value increases.

  In the above-described method for estimating the amplitude ratio between the known signal (CPICH signal) and the information signal (HS-PDSCH signal), the synchronous detection result is divided by the sum of the channel estimation power obtained from the channel estimation value of each path. When there is a path with a low level, the ratio of the noise component to the total channel estimated power increases. As a result, there is a problem that an error occurs in the estimated amplitude ratio.

  If a 16QAM reference signal point constellation is generated using an amplitude ratio including a large amount of error, the demodulation accuracy of the information signal is lowered, and the reception performance is degraded.

  The present invention has been made in view of such points, and even when there is a path with a low reception level due to fading, the channel estimation power for each path is used to accurately estimate the amplitude ratio between a known signal and an information signal, An object of the present invention is to provide a receiving apparatus and an amplitude ratio estimating method capable of improving the receiving performance.

  The receiving apparatus of the present invention averages channel estimation power in a predetermined section of a received known signal by receiving means for receiving known signals and information signals transmitted via a plurality of paths, and for each path. A calculating means for calculating an average channel estimated power; a determining means for determining a path to be used for estimating an amplitude ratio between the known signal and the information signal using the calculated average channel estimated power; and an information signal of the determined path And a dividing unit that divides the synchronous detection result by the channel estimation power of the known signal of the path.

  According to this configuration, the average channel estimation power is calculated for each path, the path used for amplitude ratio estimation is determined using the average channel estimation power, and the synchronous detection result of the determined path is divided by the channel estimation power. Therefore, it is possible to perform amplitude ratio estimation after excluding paths with low average channel estimation power and poor reception status, and use channel estimation power for each path even when there are paths with low reception levels due to fading. Thus, it is possible to accurately estimate the amplitude ratio between the known signal and the information signal and improve the reception performance.

  The receiving apparatus of the present invention employs a configuration in which the determining means determines a path having the maximum average channel estimation power as a path to be used for amplitude ratio estimation.

  According to this configuration, since the path having the maximum average channel estimation power is used for the amplitude ratio estimation, the amplitude ratio between the known signal and the information signal of the path that is considered to have the relatively best reception state and little noise. Can be estimated, and the accuracy of estimating the amplitude ratio can be improved.

  The receiving apparatus of the present invention employs a configuration in which the determining means determines a path whose average channel estimation power is equal to or greater than a predetermined threshold as a path used for amplitude ratio estimation.

  According to this configuration, since a path whose average channel estimation power is equal to or greater than a predetermined threshold is used for amplitude ratio estimation, only known signals and information signals of a path whose reception state is considered to be better than a certain reference and less noise are used. Thus, the amplitude ratio can be estimated, and the accuracy of estimating the amplitude ratio can be improved.

  The receiving apparatus of the present invention further includes average noise power calculating means for calculating the average noise power for each path by averaging the noise power of a predetermined section of the noise component included in the received known signal, The determining means adopts a configuration in which a path having a maximum ratio of the average channel estimated power to the average noise power is determined as a path used for amplitude ratio estimation.

  According to this configuration, since the path having the maximum ratio of the average channel estimated power to the average noise power for each path is used for the amplitude ratio estimation, the channel estimated power is the largest compared with the noise power, and the reception state is relatively the most. It is possible to estimate the amplitude ratio between the known signal and the information signal of the path considered to be good, and it is possible to improve the estimation accuracy of the amplitude ratio.

  The receiving apparatus of the present invention further includes average noise power calculating means for calculating the average noise power for each path by averaging the noise power of a predetermined section of the noise component included in the received known signal, The determining means adopts a configuration in which a path whose ratio of the average channel estimated power to the average noise power is equal to or greater than a predetermined threshold is determined as a path used for amplitude ratio estimation.

  According to this configuration, a path whose ratio of average channel estimated power to average noise power for each path is equal to or greater than a predetermined threshold is used for amplitude ratio estimation, so that the channel estimated power satisfies a certain standard compared to noise power. It is possible to estimate the amplitude ratio between only the known signal and the information signal of the path that is considered to have a good reception state, and it is possible to improve the estimation accuracy of the amplitude ratio.

  In the receiving apparatus of the present invention, the determination unit includes a reliability comparison unit that compares the reliability of a path determined for each predetermined section with the reliability of a path determined in another section, and the most reliable A configuration is adopted in which an amplitude ratio estimated from a path determined in a section with a high degree is determined as an amplitude ratio to be used for demodulation of all sections in which reliability is compared.

  According to this configuration, the reliability of the paths determined for each section is compared, and all sections are demodulated using the amplitude ratio estimated from the path of the section with high reliability. Demodulation can be performed using the path with the highest reliability, and the demodulation performance can be further improved.

  The receiving apparatus of the present invention employs a configuration in which the reliability comparison unit compares the reliability of paths determined in a predetermined number of sections with each other.

  According to this configuration, since the reliability of paths determined in a predetermined number of sections is compared with each other, the amplitude ratio can be estimated with high accuracy and the demodulation performance can be further improved.

  The receiving apparatus of the present invention employs a configuration in which the reliability comparison unit compares the reliability of the path determined in the past interval with the reliability of the path determined in the current interval.

  According to this configuration, in order to compare the reliability of the path determined in the past interval with the reliability of the path determined in the current interval, demodulation is started when the amplitude ratio is calculated in the current interval. It is possible to prevent the increase in processing time while improving the demodulation performance.

  The receiving apparatus according to the present invention employs a configuration in which the reliability comparison unit compares the determined average channel estimation power or a ratio of average channel estimation power to average noise power of the determined paths as reliability.

  According to this configuration, since the average channel estimation power of the determined path or the ratio of the average channel estimation power to the average noise power is compared as the reliability, there is no need to calculate the reliability again, thereby preventing an increase in arithmetic processing. can do.

  The mobile terminal device of the present invention employs a configuration having any of the above-described receiving devices.

  According to this configuration, it is possible to achieve the same operational effects as those of the receiving device described above in the mobile terminal device.

  The base station apparatus of the present invention employs a configuration having any of the receiving apparatuses described above.

  According to this configuration, the same function and effect as those of the receiving device described above can be realized in the base station device.

  The amplitude ratio estimation method according to the present invention includes a step of receiving a known signal and an information signal transmitted via a plurality of paths, and averaging channel estimation power in a predetermined section of the received known signal for each path. Calculating an average channel estimated power of the signal, determining a path to be used for estimating an amplitude ratio between the known signal and the information signal using the calculated average channel estimated power, and synchronizing the information signal of the determined path Dividing the detection result by the channel estimation power of the known signal of the path.

  According to this method, the average channel estimation power is calculated for each path, the path to be used for amplitude ratio estimation is determined using the average channel estimation power, and the synchronous detection result of the determined path is divided by the channel estimation power. Therefore, it is possible to perform amplitude ratio estimation after excluding paths with low average channel estimation power and poor reception status, and use channel estimation power for each path even when there are paths with low reception levels due to fading. Thus, it is possible to accurately estimate the amplitude ratio between the known signal and the information signal and improve the reception performance.

  According to the present invention, even when there is a path with a low reception level due to fading, it is possible to accurately estimate the amplitude ratio between a known signal and an information signal using the channel estimation power for each path and improve reception performance. .

  The gist of the present invention is to select a path with high channel estimation power and estimate the amplitude ratio between the known signal and the information signal using only the channel estimation power and the synchronous detection result of this path.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a main configuration of the receiving apparatus according to Embodiment 1 of the present invention. 1 includes a radio reception unit 100, finger units 110-1 to 110-n, a path determination unit 120, a rake combining unit 130, a fading removal unit 140, an amplitude ratio averaging unit 150, and a reference signal point generation unit. 160, a demodulator 170, and a decoder 180.

  Radio receiving section 100 receives a signal modulated by 16QAM via an antenna, and performs predetermined radio reception processing (down-conversion, A / D conversion, etc.) on the received signal.

  The finger units 110-1 to 110-n are provided corresponding to a plurality of paths through which signals are transmitted, and obtain channel estimation power from CPICH symbols (known signals) included in received signals of the respective paths. Synchronously detect the HS-PDSCH symbol (information signal).

  The path determination unit 120 determines a path to be used for amplitude ratio estimation using the channel estimation power obtained by the finger units 110-1 to 110-n. The configurations of the finger units 110-1 to 110-n and the path determination unit 120 will be described in detail later.

  The rake combining unit 130 rake combines the synchronous detection results of the HS-PDSCH symbols output from the finger units 110-1 to 110-n.

  The fading removal unit 140 divides the HS-PDSCH symbol of the path determined by the path determination unit 120 by the channel estimation power obtained from the CPICH symbol of this path.

  The amplitude ratio averaging unit 150 calculates the amplitude ratio between CPICH and HS-PDSCH by averaging the absolute value of the division result in symbol units by the fading removal unit 140 over a predetermined interval such as one slot.

  The reference signal point generation unit 160 generates a reference signal point arrangement indicating signal point candidates of 16QAM symbols using the sum of the channel estimation power of each path and the amplitude ratio.

  The demodulating unit 170 demodulates the Rake combining result by determining which signal point in the reference signal point arrangement corresponds to the Rake combining result of the Rake combining unit 130 and obtaining likelihood information.

  Decoding section 180 decodes the demodulation result using the likelihood information obtained by demodulation section 170 and outputs decoded data.

  FIG. 2 is a block diagram showing an internal configuration of finger unit 110-1 according to the first embodiment. The finger portions 110-1 to 110-n all have the same configuration.

  CPICH despreading section 111 despreads the CPICH signal which is a known signal, and outputs the despread result in symbol units.

  Channel estimation section 112 performs channel estimation from the CPICH despreading result, and calculates a channel estimation value in the path corresponding to finger section 110-1.

  The complex conjugate calculation unit 113 calculates the complex conjugate of the channel estimation value.

  HS-PDSCH despreading section 114 despreads the HS-PDSCH signal, which is an information signal, and outputs the despread result in symbol units.

  The synchronous detection unit 115 performs synchronous detection on the despreading result of the HS-PDSCH using the complex conjugate of the channel estimation value, outputs the synchronous detection result to the path determination unit 120 (this output is assumed to be C), and Rake combining Output to the unit 130.

  Multiplier 116 multiplies the channel estimation value and the complex conjugate of the channel estimation value to calculate channel estimation power indicating the power of CPICH in symbol units. This channel estimation power is output to the path determination unit 120 as it is (this output is A) and also output to the average value calculation unit 117.

  The average value calculation unit 117 averages the channel estimation power over a predetermined interval such as one slot, for example, and outputs the obtained average channel estimation power to the path determination unit 120 (this output is B).

  FIG. 3 is a block diagram illustrating an internal configuration of the path determination unit 120 according to the first embodiment.

  Channel estimation power summation section 121 sums up all n channel estimation powers input as A from finger sections 110-1 to 110-n and outputs the sum value to reference signal point generation section 160. Further, channel estimation power summation section 121 outputs input A corresponding to the path notified from maximum value detection section 122 described later to fading removal section 140.

  Maximum value detector 122 compares n average channel estimated powers input as B from finger units 110-1 to 110-n, respectively, and detects the maximum value. The maximum value detection unit 122 notifies the channel estimation power summation unit 121 and a path selection unit 123 (to be described later) of the path having the maximum average channel estimation power.

  The path selection unit 123 performs fading removal of the synchronous detection result corresponding to the path notified from the maximum value detection unit 122 among the n synchronous detection results input as C from the finger units 110-1 to 110-n, respectively. Output to the unit 140.

  Next, the operation of the receiving apparatus configured as described above will be described.

  First, signals are received from a plurality of paths by the wireless reception unit 100 via an antenna, and predetermined wireless reception processing (down-conversion, A / D conversion, etc.) is performed. This received signal is modulated by 16QAM and includes a CPICH signal that is a known signal and an HS-PDSCH signal that is an information signal. Then, the received signal for each path is input to CPICH despreading section 111 and HS-PDSCH 114 in finger sections 110-1 to 110-n, respectively.

  The signal input to CPICH despreading section 111 is despread with the CPICH spreading code, and the despread result is output to channel estimation section 112 in units of symbols. Then, channel estimation section 112 performs channel estimation from the CPICH despreading result, and the channel estimation value is output to complex conjugate calculation section 113 and multiplier 116. When the channel estimation value is output to complex conjugate calculation section 113, the complex conjugate of the channel estimation value is calculated and multiplied by the channel estimation value by multiplier 116 to obtain channel estimation power in symbol units. This channel estimation power corresponds to the power of the CPICH symbol.

  The channel estimation power is output as an output A to the channel estimation power summation unit 121 in the path determination unit 120, and the average value calculation unit 117 calculates an average channel estimation power over a predetermined section such as one slot, for example. Is output to the maximum value detection unit 122 in the path determination unit 120.

  On the other hand, the signal input to HS-PDSCH despreading section 114 is despread with the despreading code for HS-PDSCH, and the despreading result is output to synchronous detection section 115 on a symbol basis. Then, synchronous detection of the HS-PDSCH symbol is performed by the synchronous detector 115 using the complex conjugate of the channel estimation value. The synchronous detection result is output as an output C to the path selection unit 123 in the path determination unit 120 and to the Rake synthesis unit 130. The synchronous detection results output from the finger units 110-1 to 110-n are Rake combined by the Rake combining unit 130, and the results are output to the demodulation unit 170.

  The outputs A to C are respectively output from the finger units 110-1 to 110-n to the path determination unit 120. In other words, n outputs A to C are input to each processing unit in the path determination unit 120.

  The path determination unit 120 determines a path to be used for calculating the amplitude ratio as follows.

  That is, the maximum value detection unit 122 detects the maximum value of the average channel estimated power as the input B, and the path corresponding to the maximum value of the average channel estimated power is the path used for the amplitude ratio calculation. As described above, the average channel estimated power is obtained by averaging channel estimated power in symbol units over a predetermined section such as one slot. Therefore, by detecting the maximum value of the average channel estimated power, it is possible to exclude a path where the channel estimated power is small when viewed in the short interval average and to select a path with a stable large channel estimated power. it can.

  Then, information on the path with the maximum average channel estimation power is notified to the channel estimation power summation unit 121 and the path selection unit 123. When this information is notified, the input A output from the finger unit corresponding to the path among the n inputs A (channel estimated power in symbol units) is input to the fading removal unit 140 by the channel estimation power summation unit 121. Is output. Also, n inputs A corresponding to all paths are added together by channel estimation power adding section 121 and output to reference signal point generating section 160.

  On the other hand, when information on the path with the maximum average channel estimation power is notified to the path selection unit 123, the path selection unit 123 corresponds to the path among n inputs C (synchronous detection result in symbol units). The input C output from the finger unit is output to the fading removal unit 140.

  As a result, the channel estimation power obtained from the CPICH symbol of the path with a stable and large channel estimation power and the synchronous detection result of the HS-PDSCH symbol of this path are output to the fading removal section 140. That is, the channel estimation power and the synchronous detection result output to fading removal section 140 are based on the channel estimation value of the path with a high reception level, and have high accuracy.

  Then, fading removal section 140 divides the HS-PDSCH symbol synchronous detection result by the channel estimation power, and outputs the division result to amplitude ratio averaging section 150. The absolute value of the division result is averaged over a predetermined interval such as one slot by the amplitude ratio averaging unit 150, and the obtained average value is sent to the reference signal point generation unit 160 as the amplitude ratio between CPICH and HS-PDSCH. Is output.

  Then, when the reference signal point generation unit 160 uses the amplitude ratio and the channel estimation power summation value calculated by the channel estimation power summation unit 121, symbols modulated in 16QAM are arranged on the IQ plane. Further, a reference signal point arrangement indicating 16 signal point candidates that can be signal points is generated. The reference signal point arrangement is notified to the demodulator 170, and the demodulator 170 determines which signal point of the reference signal point arrangement the Rake synthesis result output from the Rake synthesis unit 130 indicates. Thus, demodulation is performed. At this time, the likelihood of the demodulation result is notified to the decoding unit 180 as likelihood information.

  The demodulation result is decoded by the decoding unit 180 using the likelihood information, and decoded data is output.

Next, the calculation of the amplitude ratio according to the present embodiment will be specifically described using mathematical expressions. In the following description, the average amplitude A _p CPICH symbols (known signals), the average amplitude of the HS-PDSCH symbol (information signal) and A _d. In addition, it is assumed that a section in which the average channel estimation power is calculated and averaged by the amplitude ratio averaging unit 150 is one slot, and one slot includes 160 symbols.

First, the channel estimation value for the k-th HS-PDSCH symbol obtained by the channel estimation unit 112 in the finger unit 110-i is assumed to be A _p [α _ik ]. If the complex conjugate of this channel estimation value is A _p [α _ik ] ^* , the synchronous detection result x _ik of the HS-PDSCH symbol output from the synchronous detector 115 in the finger unit 110-i is expressed by the following equation ( It can be expressed as 1).

In Equation (1), S _k represents the HS-PDSCH transmission symbol normalized so that the power is 1, and α _ik represents actual fading. Therefore, the equation (1) is _obtained by calculating the complex conjugate A _p [α _ik ] ^* of the channel estimation value by channel estimation from the received symbol obtained by multiplying the HS-PDSCH symbol A _d S _k actually transmitted by fading α _ik. A state of synchronous detection by multiplication is shown.

Moreover, the average channel estimated power _Pave obtained by the average value calculation unit 117 can be expressed as the following equation (2).

The average channel estimated power P _ave determined in the finger unit 110-i in this way is output to the maximum value detecting unit 122 in the path determining unit 120, and the finger unit 110-i having the largest average channel estimated power P _ave is output. Selected.

Then, the synchronous detection result x _ik of the HS-PDSCH symbol of this finger unit 110-i is output to the fading removal unit 140 and is divided by the corresponding channel estimation power, and the absolute value of this division result is amplitude ratio averaged The unit 150 averages 160 symbols.

Thereby, the amplitude ratio (A _p / A _d ) shown in Expression (3) can be obtained.

  As described above, according to the present embodiment, the power of CPICH symbols in a plurality of paths is averaged over a predetermined section such as one slot, and the channel estimated power corresponding to the path with the maximum average channel estimated power obtained and Since the amplitude ratio between CPICH and HS-PDSCH is calculated using the synchronous detection result of the HS-PDSCH symbol, it is possible to calculate the amplitude ratio after excluding paths with low reception levels and low channel estimation accuracy. Even if there is a path with a low reception level due to fading, it is possible to accurately estimate the amplitude ratio between the known signal and the information signal using the channel estimation power for each path and improve the reception performance.

(Embodiment 2)
A feature of Embodiment 2 of the present invention is that a reference signal point arrangement is generated by applying the most reliable amplitude ratio among amplitude ratios estimated corresponding to a plurality of slots to all slots.

  The overall configuration of the receiving apparatus according to the present embodiment is the same as that of Embodiment 1 (FIG. 1), and only the internal configuration of path determining section 120 is different, and thus the description of the overall configuration is omitted.

  FIG. 4 is a block diagram illustrating an internal configuration of the path determination unit 120 according to the second embodiment. In this figure, the same parts as those in FIG.

  The reliability comparison unit 124 stores the maximum value of the average channel estimated power for one slot detected by the maximum value detection unit 122 as reliability, and compares the reliability of a plurality of slots. Further, the reliability comparison unit 124 notifies the amplitude ratio averaging unit 150 of the slot with the highest reliability. For example, in HSDPA, since the HS-PDSCH is composed of 3 slots, the reliability comparison unit 124 compares the maximum value of the average channel estimated power for 1 slot with respect to 3 slots.

  Next, the operation of the receiving apparatus configured as described above will be described. The operation from when the signal is received until the outputs A to C are input to each processing unit in the path determination unit 120 by the finger units 110-1 to 110-n is the same as in the first embodiment. The description is omitted.

  The path determination unit 120 determines a path to be used for calculating the amplitude ratio as follows.

  That is, the maximum value detection unit 122 detects the maximum value of the average channel estimated power that is the input B, and notifies the path selection unit 123 and the reliability comparison unit 124 of the path corresponding to this maximum value. Further, the detected maximum value is notified to the reliability comparison unit 124. Then, the reliability comparing unit 124 temporarily stores the maximum value notified from the maximum value detecting unit 122 as the reliability, and notifies the channel estimation power summing unit 121 of the path corresponding to the maximum value. The channel estimation power summation unit 121 outputs the channel estimation power of this path to the fading removal unit 140.

  Here, the input B to the maximum value detection unit 122 is an average channel estimated power obtained by averaging the channel estimated power of symbols over one slot. Therefore, the reliability comparison unit 124 stores the reliability corresponding to one slot. Then, the maximum value of the average channel estimated power of the next slot is continuously stored in the reliability comparison unit 124.

  In this way, when the maximum value of the average channel estimated power corresponding to a predetermined number of slots is stored in the reliability comparison unit 124 as reliability, these reliability are compared with each other, and the slot with the highest reliability is obtained. Information is notified to the amplitude ratio averaging unit 150.

  On the other hand, the path corresponding to the maximum value detected by the maximum value detection unit 122 is also notified to the path selection unit 123. Then, the path selection unit 123 outputs the synchronous detection result of the path corresponding to this maximum value to the fading removal unit 140.

  Thereafter, as in Embodiment 1, fading removal section 140 divides the HS-PDSCH symbol synchronous detection result by channel estimation power, and outputs the division result to amplitude ratio averaging section 150. The division result is averaged over one slot by the amplitude ratio averaging unit 150, and the obtained average value becomes the amplitude ratio between CPICH and HS-PDSCH.

  Here, the amplitude ratio is obtained by averaging the division results in slot units. In the present embodiment, the amplitude ratio averaging unit 150 calculates the amplitude ratio corresponding to the slot and temporarily stores it without immediately outputting it to the reference signal point generating unit 160. Then, only the amplitude ratio corresponding to the slot with the highest reliability reported from the reliability comparison unit 124 is output to the reference signal point generation unit 160.

  Specifically, for example, as shown in FIG. 5, the reliability comparison unit 124 compares the reliability L1 to L3 for three slots 1 to 3. In the example shown in FIG. 5, it is assumed that L2 is the largest. Therefore, information on the slot 2 is notified to the amplitude ratio averaging unit 150, and only the R2 among the amplitude ratios R1 to R3 calculated by the amplitude ratio averaging unit 150 averaged for each of the slots 1 to 3 is obtained. This is output to the reference signal point generator 160.

  In this way, by detecting the maximum value of the average channel estimation power and comparing the maximum values for a plurality of slots, it is possible to select a path that is considered to have better channel estimation accuracy. The amplitude ratio output to the point generator 160 is more accurate than in the first embodiment.

  Then, when the reference signal point generation unit 160 uses the amplitude ratio and the channel estimation power summation value calculated by the channel estimation power summation unit 121, symbols modulated in 16QAM are arranged on the IQ plane. Further, a reference signal point arrangement indicating 16 signal point candidates that can be signal points is generated. The reference signal point arrangement is notified to the demodulator 170, and the demodulator 170 determines which signal point of the reference signal point arrangement the Rake synthesis result output from the Rake synthesis unit 130 indicates. Thus, demodulation is performed. At this time, the likelihood of the demodulation result is notified to the decoding unit 180 as likelihood information.

  The demodulation result is decoded by the decoding unit 180 using the likelihood information, and decoded data is output.

  As described above, according to the present embodiment, the maximum value of the average channel estimated power corresponding to a plurality of slots is compared as reliability, and the path with the maximum average channel estimated power in the slot with the highest reliability is supported. Since the demodulation is performed using the amplitude ratio, the amplitude ratio used for generating the reference signal point can be accurately estimated and the demodulation performance can be further improved.

  In this embodiment, the path is selected by comparing the reliability for every predetermined number of slots, but the reliability of the previous slot and the current slot is compared, and the slot for selecting the path is determined each time. You may make it do.

  That is, for example, in FIG. 5, R1 is output as the amplitude ratio for slot 1 and reliability L1 <L2 for slot 2, so R2 is output as amplitude ratio, and reliability L3 <L2 for slot 3. Therefore, R2 is output as the amplitude ratio.

  As a result, demodulation can be started without waiting for the amplitude ratios to be calculated for all the predetermined number of slots, and an increase in processing time can be prevented while improving demodulation performance.

(Embodiment 3)
A feature of the third embodiment of the present invention is that the amplitude ratio is estimated using all paths whose average channel estimation power is equal to or greater than a predetermined threshold.

  The overall configuration of the receiving apparatus according to the present embodiment is the same as that of Embodiment 1 (FIG. 1), and only the internal configuration of path determining section 120 is different, and thus the description of the overall configuration is omitted.

  FIG. 6 is a block diagram illustrating an internal configuration of the path determination unit 120 according to the third embodiment.

  Channel estimation power summation section 125 sums all n channel estimation powers input as A from finger sections 110-1 to 110-n and outputs the sum value to reference signal point generation section 160. Channel estimation power summation section 125 sums up input A corresponding to the path notified from threshold comparison section 126 described later, and outputs the sum value to fading removal section 140.

  The threshold comparison unit 126 compares the n average channel estimated powers input as B from the finger units 110-1 to 110-n, respectively, with a predetermined threshold. The threshold comparison unit 126 notifies the channel estimation power summation unit 125 and a path selection unit 127 described later of a path whose average channel estimation power is greater than or equal to a predetermined threshold.

  The path selection unit 127 includes, as a Rake combining unit, the synchronous detection result corresponding to the path notified from the threshold comparison unit 126 among the n synchronous detection results input as C from the finger units 110-1 to 110-n. Output to 128.

  The Rake combining unit 128 Rake combines the synchronous detection result output from the path selection unit 127 and outputs the Rake combining result to the fading removal unit 140.

  Next, the path determination operation of the path determination unit 120 configured as described above will be described.

  First, the threshold comparison unit 126 compares the average channel estimated power, which is the input B, with a predetermined threshold, and information on paths having average channel estimated power equal to or greater than the predetermined threshold is obtained by the channel estimated power summing unit 125 and the path selection unit 127 is notified. When this information is notified, the channel estimation power summation unit 125 sums the input A (symbol unit channel estimation power) output from the finger unit corresponding to the path, and outputs the sum value to the fading removal unit 140. Is done. Also, n inputs A corresponding to all paths are added together by channel estimation power adding section 125 and output to reference signal point generating section 160.

  On the other hand, when information on a path having an average channel estimation power equal to or greater than a predetermined threshold is notified to the path selection unit 127, the path selection unit 127 inputs the input C (symbol unit) output from the finger unit corresponding to the path. (Synchronous detection result) is output to the Rake combining unit 128. Then, the Rake combining unit 128 performs Rake combining on the synchronous detection result output from the path selecting unit 127 and outputs the Rake combining result to the fading removing unit 140.

  As a result, the sum of the channel estimation power obtained from the CPICH symbols of the path with stable and large channel estimation power and the result of Rake combining the synchronous detection results of the HS-PDSCH symbols of these paths to the fading removal section 140 It is output.

  Hereinafter, as in Embodiment 1, the amplitude ratio between CPICH and HS-PDSCH is obtained, and the HS-PDSCH symbol is demodulated and decoded.

  In the present embodiment, if the average channel estimation power is equal to or greater than a predetermined threshold, a plurality of paths are selected. Therefore, when the reception levels of many paths are good, the average channel estimation power is maximum. Only one path is selected, and information held by another path is not discarded.

  As described above, according to the present embodiment, the sum of channel estimation power corresponding to a path whose average channel estimation power is equal to or greater than a predetermined threshold and the Rake combination result of the HS-PDSCH symbol subjected to synchronous detection are used. In order to calculate the amplitude ratio, it is possible to calculate the amplitude ratio after excluding the paths with low reception level and low channel estimation accuracy, and to effectively use the information that the path has good reception status. The reception performance can be further improved.

  In the present embodiment, the amplitude ratio is estimated by using all paths whose average channel estimation power is equal to or greater than a predetermined threshold. However, when there is no path greater than the predetermined threshold, the embodiment The amplitude ratio may be estimated using a path having a maximum average channel estimation power as in FIG.

(Embodiment 4)
A feature of the fourth embodiment of the present invention is that a path used for estimating an amplitude ratio is determined in consideration of a noise component included in CPICH.

  Since the overall configuration of the receiving apparatus according to this embodiment is the same as that of Embodiment 1 (FIG. 1), description thereof is omitted.

  FIG. 7 is a block diagram showing an internal configuration of finger unit 110-1 according to the fourth embodiment. In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. Further, the finger portions 110-1 to 110-n all have the same configuration.

  The noise extraction unit 118 extracts a noise component from the CPICH despreading result, and outputs the noise power for each symbol to the average value calculation unit 119.

  The average value calculation unit 119 averages the noise power over a predetermined section such as one slot, for example, and outputs the obtained average noise power to the path determination unit 120 (this output is assumed to be D). The average value calculation unit 119 averages the noise power over the same section as the average value calculation unit 117.

  FIG. 8 is a block diagram illustrating an internal configuration of the path determination unit 120 according to the fourth embodiment. In this figure, the same parts as those in FIG.

  The maximum value detection unit 122a compares the division results of the average channel estimation power and the average noise power for each path output from the division unit 129 described later, and detects the maximum value. The maximum value detection unit 122a notifies the channel estimation power summation unit 121 and the path selection unit 123 of the path with the maximum division result.

  The division unit 129 divides n average channel estimation powers and n average noise powers input as B and D from the finger units 110-1 to 110-n, respectively, and obtains n division results obtained. It outputs to the maximum value detection part 122a.

  Next, the operation of the receiving apparatus configured as described above will be described. The operation from when the signal is received until the outputs A to C are input to each processing unit in the path determination unit 120 by the finger units 110-1 to 110-n is the same as in the first embodiment. The description is omitted.

  In the present embodiment, a noise component is extracted from the CPICH symbol by the noise extraction unit 118, and the power of the noise component is averaged over one slot by the average value calculation unit 119. Then, in addition to the above outputs A to C, the average noise power is output as an output D to the division unit 129 in the path determination unit 120.

  The path determination unit 120 determines a path to be used for calculating the amplitude ratio as follows.

  First, the division unit 129 divides the average channel estimation power as the input B and the average noise power as the input D, and outputs the division result for each path to the maximum value detection unit 122a. Then, the maximum value detection unit 122a detects the maximum value from the division result of each path, and the path corresponding to the maximum value of the division result is used as the path used for the amplitude ratio calculation. To the unit 123.

  Thus, by comparing the ratio of the average channel estimated power and the average noise power and selecting the path corresponding to the maximum value, it is possible to select the path having a CPICH symbol component larger than the noise component. In addition, a path having a good reception state can be selected as a path for calculating the amplitude ratio.

  Hereinafter, as in the first embodiment, the channel estimation power and the synchronous detection result of the selected path are output to the fading removal unit 140 and divided, and the absolute value of the division result is averaged by the amplitude ratio averaging unit 150. Thus, the amplitude ratio between CPICH and HS-PDSCH is obtained.

  Thus, according to the present embodiment, since the amplitude ratio is calculated using the channel estimation power and the synchronous detection result corresponding to the path having the maximum ratio of the average channel estimation power and the average noise power, the reception level Amplitude ratio can be calculated after removing paths with low noise ratio and high noise component ratio. Even if there is a path with low reception level due to fading, known signal and information can be obtained using channel estimation power for each path. It is possible to accurately estimate the amplitude ratio with the signal and improve the reception performance.

(Embodiment 5)
A feature of the fifth embodiment of the present invention is that the amplitude ratio is estimated using all paths having an average channel estimation power equal to or greater than a predetermined threshold in consideration of a noise component included in CPICH.

  Since the overall configuration of the receiving apparatus according to this embodiment is the same as that of Embodiment 1 (FIG. 1), description thereof is omitted. Moreover, since the internal structure of the finger parts 110-1 to 110-n according to the present embodiment is the same as that of the fourth embodiment (FIG. 7), the description thereof is omitted.

  FIG. 9 is a block diagram illustrating an internal configuration of the path determination unit 120 according to the fifth embodiment. In the figure, the same parts as those in FIG.

  The threshold comparison unit 126a compares the division result of the average channel estimation power and average noise power for each path output from the division unit 129 with a predetermined threshold. The threshold comparison unit 126a notifies the channel estimation power summation unit 125 and the path selection unit 127 of a path whose division result is equal to or greater than a predetermined threshold.

  Next, the path determination operation of the path determination unit 120 configured as described above will be described.

  First, as in the fourth embodiment, the ratio between the average channel estimated power that is input B and the average noise power that is input D is calculated for each path by division by division unit 129, and the division result is a threshold value. It is output to the comparison unit 126a. Then, the threshold comparison unit 126a compares the division result with a predetermined threshold value, and notifies the channel estimation power summation unit 125 and the path selection unit 127 of information on the path corresponding to the division result equal to or greater than the predetermined threshold value. When this information is notified, the channel estimation power summation unit 125 sums the input A (symbol unit channel estimation power) output from the finger unit corresponding to the path, and outputs the sum value to the fading removal unit 140. Is done. Also, n inputs A corresponding to all paths are added together by channel estimation power adding section 125 and output to reference signal point generating section 160.

  On the other hand, when the path selection unit 127 is notified of the path information corresponding to the division result equal to or greater than the predetermined threshold, the path selection unit 127 outputs the input C (symbol unit synchronization) output from the finger unit corresponding to the path. Detection result) is output to the Rake combining unit 128. Then, the Rake combining unit 128 performs Rake combining on the synchronous detection result output from the path selecting unit 127 and outputs the Rake combining result to the fading removing unit 140.

  As a result, a fading removal unit is obtained by Rake combining the sum of the channel estimation power obtained from the CPICH symbol of the path whose channel estimation power is larger than the noise power and the synchronous detection result of the HS-PDSCH symbol of these paths. It is output to 140.

  Hereinafter, as in Embodiment 1, the amplitude ratio between CPICH and HS-PDSCH is obtained, and the HS-PDSCH symbol is demodulated and decoded.

  As described above, according to the present embodiment, the sum of channel estimation power corresponding to a path whose ratio of average channel estimation power and average noise power is equal to or greater than a predetermined threshold, and the synchronously detected HS-PDSCH symbol Since the amplitude ratio is calculated using the Rake combination result, the amplitude ratio can be calculated after excluding the path having a low reception level and relatively high noise power, and a path having a good reception state can be obtained. The stored information can be used effectively, and reception performance can be further improved.

  In this embodiment, the amplitude ratio is estimated using all the paths whose ratio between the average channel estimated power and the average noise power is equal to or higher than a predetermined threshold, but there is no path higher than the predetermined threshold. In this case, as in the fourth embodiment, the amplitude ratio may be estimated using a path having a maximum ratio between the average channel estimation power and the average noise power.

  In the second embodiment, the maximum value of the average channel estimated power is stored as the reliability and the comparison is made for a plurality of slots. However, the second embodiment may be combined with the third to fifth embodiments. it can.

  That is, when the second embodiment and the third embodiment are combined, the total value of the average channel estimated power of paths whose average channel estimated power is equal to or greater than a predetermined threshold is set as the reliability. Further, when the second embodiment and the fourth embodiment are combined, the maximum value of the ratio between the average channel estimation power and the average noise power is set as the reliability. Similarly, when combining the second embodiment and the fifth embodiment, the average channel estimation power and average noise power of the selected path are combined by Rake, and the average channel estimation power and average noise power after Rake combination are The ratio is the reliability.

  Further, in each of the above embodiments, fading fluctuation is detected from the channel estimation result, and the length of the section in which the channel estimation power or noise power is averaged is changed or the reliability is compared according to the fading fluctuation. The number of slots may be changed.

  Specifically, for example, when fading fluctuation is large, the above section is shortened, and when the fluctuation amount is small, the above section is lengthened. As a result, even when fading fluctuation, which is considered to cause large fluctuations in the channel estimation power for each symbol of each path, the path selection period used for calculating the amplitude ratio is shortened, and the amplitude ratio estimation is always performed from the optimum path. It can be performed.

  The reception apparatus and the amplitude ratio estimation method according to the present invention accurately estimate the amplitude ratio between a known signal and an information signal using channel estimation power for each path even when there is a path with a low reception level due to fading, and receive Receiver for receiving a signal modulated by a modulation scheme such as 16QAM, which can improve performance and requires a ratio of transmission level of known signal to information signal to demodulate received signal, and amplitude ratio estimation method It is useful as such.

The block diagram which shows the principal part structure of the receiver which concerns on embodiment of this invention The block diagram which shows the internal structure of the finger part which concerns on Embodiment 1-3 of this invention. The block diagram which shows the internal structure of the path determination part which concerns on Embodiment 1 of this invention. The block diagram which shows the internal structure of the path determination part which concerns on Embodiment 2 of this invention. The figure for demonstrating the amplitude ratio selection operation | movement which concerns on Embodiment 2. FIG. The block diagram which shows the internal structure of the path determination part which concerns on Embodiment 3 of this invention. The block diagram which shows the internal structure of the finger part which concerns on Embodiment 4, 5 of this invention. The block diagram which shows the internal structure of the path determination part which concerns on Embodiment 4 of this invention. The block diagram which shows the internal structure of the path determination part which concerns on Embodiment 5 of this invention. Block diagram showing a configuration example of a conventional apparatus for estimating an amplitude ratio

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Radio | wireless receiving part 110-1-110-n Finger part 111 CPICH despreading part 112 Channel estimation part 113 Complex conjugate calculation part 114 HS-PDSCH despreading part 115 Synchronous detection part 116 Multiplier 117,119 Average value calculation part 118 Noise Extraction unit 120 Path determination unit 121, 125 Channel estimation power summation unit 122, 122a Maximum value detection unit 123, 127 Path selection unit 124 Reliability comparison unit 126, 126a Threshold comparison unit 128, 130 Rake synthesis unit 129 Division unit 140 Fading removal Unit 150 amplitude ratio averaging unit 160 reference signal point generation unit 170 demodulation unit 180 decoding unit

Claims (12)

Receiving means for receiving known signals and information signals transmitted via a plurality of paths;
Calculating means for calculating an average channel estimated power for each path by averaging the channel estimated power of a predetermined section of the received known signal;
Determining means for determining a path to be used for estimating an amplitude ratio between the known signal and the information signal using the calculated average channel estimation power;
Division means for dividing the synchronous detection result of the information signal of the determined path by the channel estimation power of the known signal of the path;
A receiving apparatus comprising: The determining means includes
The receiving apparatus according to claim 1, wherein a path having the maximum average channel estimation power is determined as a path used for amplitude ratio estimation. The determining means includes
The receiving apparatus according to claim 1, wherein a path whose average channel estimation power is equal to or greater than a predetermined threshold is determined as a path used for amplitude ratio estimation. Average noise power calculating means for calculating the average noise power for each path by averaging the noise power of a predetermined section of the noise component included in the received known signal,
The determining means includes
The receiving apparatus according to claim 1, wherein a path having a maximum ratio of the average channel estimated power to the average noise power is determined as a path to be used for amplitude ratio estimation. Average noise power calculating means for calculating the average noise power for each path by averaging the noise power of a predetermined section of the noise component included in the received known signal,
The determining means includes
The receiving apparatus according to claim 1, wherein a path whose ratio of the average channel estimated power to the average noise power is equal to or greater than a predetermined threshold is determined as a path used for amplitude ratio estimation. The determining means includes
A reliability comparison unit that compares the reliability of a path determined for each predetermined section with the reliability of a path determined in another section;
2. The receiving apparatus according to claim 1, wherein an amplitude ratio estimated from a path determined in a section having the highest reliability is determined as an amplitude ratio used for demodulation of all sections in which reliability is compared. The reliability comparison unit includes:
7. The receiving apparatus according to claim 6, wherein reliability of paths determined in a predetermined number of sections is compared with each other. The reliability comparison unit includes:
7. The receiving apparatus according to claim 6, wherein the reliability of the path determined in the past section is compared with the reliability of the path determined in the current section. The reliability comparison unit includes:
The receiving apparatus according to claim 6, wherein the average channel estimation power of the determined path or a ratio of the average channel estimation power to the average noise power is compared as reliability.   A mobile terminal apparatus comprising the receiving apparatus according to claim 1.   A base station apparatus comprising the receiving apparatus according to claim 1. Receiving known and information signals transmitted via a plurality of paths;
Averaging the channel estimation power of a predetermined section of the received known signal to calculate an average channel estimation power for each path;
Determining a path to be used for amplitude ratio estimation of the known signal and information signal using the calculated average channel estimation power;
Dividing the synchronous detection result of the information signal of the determined path by the channel estimation power of the known signal of the path;
An amplitude ratio estimation method characterized by comprising:

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