JP2006253963A - Phase-estimating device, phase-estimating method and receiving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance reception performance, when the diversity transmission pattern of a common pilot channel is received. <P>SOLUTION: In a phase-estimating device, a control part 109 changes the magnitude of a summing average section, in response to the timing difference (frame offset) between a data channel and the common pilot channel. A phase-estimating part 105 computes the phase estimation value in the changed summing average section and supplies it to a synchronization detection part 106. Since it is possible to avoid the occurrence of the case, where a past and future symbol in a pilot channel section used for a phase estimation are not symmetric with respect to data symbol section, the reception performance can be enhanced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a phase estimation device, a phase estimation method, and a reception device used in a base station and a mobile station in a mobile communication system using a code division multiple access (hereinafter referred to as “CDMA”) system.

  A base station and a mobile station in a mobile communication system using the direct spreading CDMA system realizes highly efficient synchronous detection reception using a phase estimation method. That is, in a mobile communication environment, amplitude fluctuation and reception fluctuation due to Rayleigh fading accompanying relative movement between the mobile station and the base station occur. Therefore, when decoding received data, a value that gives a decoding criterion is required.

  The value giving the decoding criterion is obtained by estimating the phase being received from the phase value of the received decoded value of the common pilot channel (CPICH) that is known data. A method of correcting the correlation value with the data channel (Dedicated Physical Channel: DPCH) in the received signal using the phase estimation value and performing RAKE (rake) synthesis is employed.

  Here, several techniques for improving the performance of the phase estimation method for obtaining a value that gives a decoding criterion have been proposed. For example, Patent Document 1 proposes a phase estimation method that divides a data symbol in a slot into a plurality of data symbols and selects a pilot appropriate for calculating a phase estimation value in each data symbol section.

  Patent Document 2 proposes a method of averaging while changing the addition average interval of phase estimation depending on the frequency error.

  Further, in Patent Document 3, when a transmission pattern of a common pilot channel CPICH transmitted from each antenna that performs transmission diversity is determined in accordance with the mobile communication standard 3GPP TS25.211, reception of a slot of one symbol past is received. There has been proposed a method for estimating the phase using 9 symbols of the symbol and the symbol of the current slot. In addition, the diversity transmission pattern of the common pilot channel defined in the mobile communication standard 3GPP TS25.211 is as shown in FIG.

In FIG. 9, one frame is composed of two slot sections as shown in frame # (i-1), and each slot section is composed of ten symbols. From antenna # 1, a symbol A is inserted into each slot and transmitted. On the other hand, from antenna # 2, basically, symbols A and A and inverted symbols -A and -A are alternately inserted and transmitted every two slots.
International Publication No. 00/060761 Pamphlet Japanese Patent Laid-Open No. 2002-217783 JP 2003-218741 A

  However, when the diversity transmission pattern of the common pilot channel compliant with the mobile communication standard 3GPP TS25.211 is used, if the conventional phase estimation method is used, the past in the common pilot channel section used for phase estimation for the data symbol period And future symbols may not be symmetrical, and there is a problem that the characteristics deteriorate.

  The present invention has been made in view of the above points, and a phase estimation device capable of improving reception performance when a diversity pilot transmission pattern of a common pilot channel compliant with the mobile communication standard 3GPP TS25.211 is used. An object is to provide an estimation method and a receiving apparatus.

  In order to solve this problem, a phase estimation device according to the present invention includes a control unit that changes the size of an addition average interval for each radio link, and a phase estimation unit that calculates a phase estimation value in the changed addition average interval. The structure which comprises is taken.

  According to this configuration, when the diversity transmission pattern of the common pilot channel compliant with the mobile communication standard 3GPP TS25.211 is used, the past and future symbols in the pilot channel section used for phase estimation with respect to the data symbol section Since it is possible to avoid the occurrence of a case where it is not symmetrical, it is possible to improve reception performance.

  In the above-described invention, the phase estimation apparatus according to the present invention employs a configuration in which the control means changes the size of the addition average interval according to the timing difference between the data channel and the pilot channel.

  According to this configuration, it is possible to avoid the case where the past and future symbols in the pilot channel section used for phase estimation are not symmetric with respect to the data symbol section.

  The phase estimation apparatus according to the present invention includes a control unit that generates channel information of a received data channel, and a phase that uses the channel information and uses different addition average sections for various data in the received data channel. A configuration including phase estimation means for calculating estimated values, respectively.

  According to this configuration, an appropriate phase estimation value can be obtained for each of various types of data in the data channel.

  The receiving apparatus according to the present invention includes a control unit that generates channel information of a data channel being received, and an addition averaging period in which phase estimation values for various types of data in the received data channel are received based on the channel information. A phase estimation unit that calculates each of the phase estimation values, and a synchronous detection that receives the channel information and selects a phase estimation value to be used according to data to be synchronously detected from a plurality of phase estimation values calculated by the phase estimation unit The structure which comprises a means is taken.

  According to this configuration, the phase estimation value is separately obtained for each region in the data channel and synchronous detection is performed, so that reception performance can be improved.

  In the receiving apparatus according to the present invention, in the above invention, the phase estimation unit calculates a phase estimation value for TPC in the received data channel, and the synchronous detection unit demodulates the TPC in the received data channel. In this case, the TPC phase estimation value calculated by the phase estimation means is used.

  According to this configuration, the TPC reception performance can be improved.

  The phase estimation method according to the present invention includes a control step of changing and controlling the size of the addition average interval for each radio link, and a phase estimation step of calculating a phase estimation value in the changed addition average interval. did.

  According to this method, when the diversity transmission pattern of the common pilot channel compliant with the mobile communication standard 3GPP TS25.211 is used, the past and future symbols in the pilot channel section used for phase estimation with respect to the data symbol section Since it is possible to avoid the occurrence of a case where it is not symmetrical, it is possible to improve reception performance.

  In the phase estimation method according to the present invention, in the above invention, in the control step, the size of the addition average interval is changed according to a timing difference between the data channel and the pilot channel.

  According to this method, it is possible to avoid the case where the past and future symbols in the pilot channel section used for phase estimation are not symmetric with respect to the data symbol section.

  The phase estimation method according to the present invention differs from a control step of generating channel information of a received data channel and a phase estimation value for various data in the received data channel in response to the channel information. And a phase estimation step for calculating each using the addition average interval.

  According to this method, an appropriate phase estimation value can be obtained for each of various types of data in the data channel.

  According to the present invention, it is possible to provide a phase estimation device, a phase estimation method, and a reception device capable of improving reception performance when a diversity pilot transmission pattern of a common pilot channel compliant with the mobile communication standard 3GPP TS25.211 is used. Can do.

  The essence of the present invention is that, when receiving a diversity transmission pattern of a common pilot channel compliant with the mobile communication standard 3GPP TS25.211, an average of calculating a phase estimation value according to a timing difference between the common pilot channel and the data channel The size of the section is changed so that a symbol that is not symmetric is not generated in the pilot channel section used for phase estimation with respect to the data symbol section. In addition, the phase estimation value for TPC section demodulation and the data section demodulation Obtaining the phase estimation value separately and separately performing synchronous detection.

  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 configuration of a receiving apparatus including the phase estimation apparatus according to Embodiment 1 of the present invention. 1 includes an antenna 101, a radio reception unit 102, a plurality of despreading units 103 for a common pilot channel CPICH, a plurality of despreading units 104 for a data channel DPCH, and phase estimation. A plurality of units 105, a plurality of synchronous detection units 106, a RAKE combining unit 107, a decoding unit 108, and a control unit 109 are provided.

  In FIG. 1, a radio reception unit 102 performs predetermined radio processing (down-conversion, demodulation processing, A / D conversion, etc.) on a signal received by an antenna 101, and a plurality of units connected in parallel. This is given to the despreading units 103 and 104.

  The plurality of despreading sections 103 and 104 are provided corresponding to a plurality of downlink signals from a plurality of radio base stations, and each perform despreading processing using different despreading codes.

  Specifically, each of the plurality of despreading sections 103 reproduces the CPICH signal using a despread code corresponding to the despread code of the corresponding radio base station. On the other hand, each of the plurality of despreading sections 104 reproduces transmission data included in the DPCH transmitted from the corresponding radio base station using a despread code corresponding to the despread code of the corresponding radio base station. .

  The result of despreading the CPICH signal in the plurality of despreading units 103 is given to the corresponding one of the plurality of phase estimation units 105. The plurality of phase estimation units 105 performs addition averaging according to the addition average interval input from the control unit 109 to obtain a phase estimation value of the signal after despreading, and gives it to the corresponding ones of the plurality of synchronous detection units 106 . Further, the despreading results of DPCH signals in the plurality of despreading sections 104 are given to the corresponding ones of the plurality of synchronous detection sections 106.

  The synchronous detection unit 106 performs synchronous detection by multiplying the DPCH despread code by the complex conjugate of the phase estimation value calculated by the phase estimation unit 105. The synchronous detection results of the plurality of synchronous detection units 106 are output to the RAKE combining unit 107.

  The RAKE combining unit 107 obtains the sum of the respective synchronous detection outputs and provides the sum to the decoding unit 108. The decoding unit 108 performs error correction decoding on the RAKE composite signal.

  The control unit 109 monitors the timing difference (frame offset) between the common pilot channel CPICH and the data channel DPCH of each radio link transmitted from the base station apparatus, and determines the addition average interval given to the phase estimation unit 105 for each radio link. Change control. This frame offset may have a timing difference between even and odd symbols.

  Next, the principle of the phase estimation method according to the first embodiment will be described with reference to FIGS. FIG. 2A is a diagram illustrating a 4-symbol phase estimation period when transmission diversity is present (when the frame offset is an odd number). FIG. 2-2 is a diagram illustrating a four-symbol phase estimation period when transmission diversity is present (when the frame offset is an even number). FIG. 3 is a diagram for explaining the principle of characteristic deterioration when the addition average interval is not symmetric. FIG. 3A shows a case where the frame offset is an odd number, and FIG. 3B shows a case where the frame offset is an even number. is there. FIG. 4A is a diagram illustrating a 6-symbol phase estimation period when transmission diversity is present (when the frame offset is an odd number). FIG. 4B is a diagram illustrating a 6-symbol phase estimation period when transmission diversity is present (when the frame offset is an even number).

  FIG. 2A shows a case where the frame offset of DPCH with respect to CPICH is 1 symbol = 256 chips. FIG. 2-2 shows a case where the DPCH frame offset with respect to CPICH is 2 symbols = 2 × 256 chips. In FIGS. 2-1 and 2-2, the addition average interval is 4 symbols = 4 × 256 chips.

  At the time of transmission diversity reception, it is necessary to obtain phase estimation values of antenna # 1 and antenna # 2 shown in FIG. Here, as an example, a method of obtaining the phase estimation values of antenna # 1 and antenna # 2 using the received data of the 0th symbol and the received data of the next 1st symbol in the first slot section of one frame will be described.

The results of despreading the received data of the 0th symbol and the received data of the 1st symbol are respectively
D _plus = α ₁ ATs + α ₂ ATs + N ₁ (1)
_Dminus = α ₁ ATs−α ₂ ATs + N ₂ (2)
And

In equations (1) and (2), α ₁ and α ₂ are channel estimation coefficients of antenna # 1 and antenna # 2, respectively. A is a symbol (complex number), N ₁ and N ₂ are noise, and Ts is a symbol time.

Adding Expression (1) and Expression (2) yields 2α ₁ ATs + N ₁ + N _2, and therefore channel estimation coefficient α ₁ of antenna # ₁ is obtained by α ₁ = Expression (1) + Expression (2) be able to. Similarly, subtracting equation (1) from equation (2) yields 2α ₂ ATs + N ₁ −N _2, and therefore channel estimation coefficient α ₂ of antenna # ₂ is expressed as α ₂ = expression (1) −expression ( 2).

  Then, as shown in FIG. 9, since antenna # 2 transmits a combination of symbol A and symbol-A, the section in which antenna # 2 transmits symbol A is adapted to equation (1), and antenna # 2 The interval in which symbol-A is transmitted is adapted to equation (2), and the phase estimation values of antenna # 1 and antenna # 2 are obtained using the symbol by the combination of symbol A and symbol-A transmitted by antenna # 2.

  Specifically, for example, as shown in FIGS. 2A and 2B, the instantaneous phase estimation values of the antenna # 1 and the antenna # 2 are obtained using a pair of even and odd symbols of the common pilot channel CPICH. Then, the values are averaged for each antenna to obtain a phase estimation value. The phase estimation value is applied to the corresponding symbol of the data channel DPCH to perform phase correction, and then synchronous detection of the data channel DPCH is performed.

  By the way, as shown in FIG. 2-2, when the frame offset is an even number, it can be seen that the addition average section used for phase estimation is not symmetric between the past and the future with respect to the symmetric data channel DPCH. On the other hand, when the frame offset is an odd number as shown in FIG. 2A, it can be seen that the addition average interval used for phase estimation is symmetric with respect to the symmetric data channel DPCH.

  Even if the number of additions is the same, comparing the case where the addition average interval is symmetric and the case where the addition average interval is not symmetric, the characteristics deteriorate as shown in FIG. In FIG. 3, when the frame offset is an odd number (FIG. 3A), the phase estimated value 304 obtained by averaging the instantaneous phase estimated values 302 and 303 with respect to the phase estimated value 301 to be obtained is the same direction. Since the vector is suitable for, the performance is good.

  On the other hand, when the frame offset is an even number (FIG. 3B), the phase estimation value 314 obtained by adding and averaging the instantaneous phase estimation values 312 and 313 to the phase estimation value 311 to be obtained is the same. Since the direction vector is not used, the characteristics deteriorate.

  Next, FIG. 4A shows a case where the DPCH frame offset with respect to CPICH is 1 symbol = 256 chips. FIG. 4B illustrates a case where the DPCH frame offset with respect to CPICH is 2 symbols = 2 × 256 chips. In FIGS. 4A and 4B, the addition average interval is 6 symbols = 6 × 256 chips.

  As shown in FIG. 4B, when the frame offset is an even number, the addition average section used for phase estimation is symmetric with respect to the data channel DPCH, so that the characteristics are good. On the other hand, as shown in FIG. 4-1, when the frame offset is an odd number, the addition average section used for phase estimation is not symmetric with respect to the data channel DPCH. To do.

  Therefore, in this example, when the frame offset is an even number, the control unit 109 gives an addition average interval of 6 × 256 chips to the phase estimation unit 105, and when the frame offset is an odd number, an addition average interval of 4 × 256 chips. To the phase estimation unit 105.

  As described above, since the addition average interval of phase estimation is changed according to the timing difference (frame offset) between the common pilot channel CPICH and the data channel DPCH, the data symbol interval is symmetrical in the pilot channel interval used for phase estimation. It is possible to prevent the occurrence of a symbol that does not become necessary, and the reception performance can be improved.

(Embodiment 2)
FIG. 5 is a block diagram showing a configuration of a reception apparatus including the phase estimation apparatus according to Embodiment 2 of the present invention. In FIG. 5, the same reference numerals are given to components that are the same as or equivalent to the components shown in FIG. 1 (Embodiment 1). Here, the description will be focused on the portion related to the second embodiment.

  As shown in FIG. 5, a receiving device 500 including the phase estimation device according to the second embodiment has a configuration shown in FIG. 1 (Embodiment 1), in which the phase estimation unit 501 is replaced with the phase estimation unit 105. A synchronous detection unit 502 is provided instead of the synchronous detection unit 106, and a control unit 503 is provided instead of the control unit 109.

  The control unit 503 gives the channel information of the currently received data channel DPCH to the phase estimation unit 501 and the synchronous detection unit 502.

  The phase estimation unit 501 calculates a plurality of addition average values and phase estimation values of the addition average section according to the channel information of the currently received data channel DPCH output from the control unit 503, and provides it to the synchronous detection unit 502 .

  The synchronous detection unit 502 performs synchronous detection while switching the phase estimation value to be used according to the channel information of the data channel DPCH that is currently received.

  FIG. 6 is a block diagram illustrating a configuration example of the phase estimation unit 501 and the synchronous detection unit 502. As shown in FIG. 6, the phase estimation unit 501 includes a TPC phase estimation unit 601 that calculates a phase estimation value in an addition average section for TPC, and data (Data) as a configuration related to the second embodiment. And a data phase estimator 602 for calculating a phase estimation value in the addition average interval.

  The synchronous detection unit 502 includes a control unit 611, a switch (SW) 612, and a complex multiplication unit 613 as a configuration related to the second embodiment.

  As shown in FIG. 7, the slot format of the downlink data channel DPCH includes a pilot (Pilot) unit 701, a TPC (Transmission Power Control) unit 702, a data (Data) unit 703, and a pilot (Pilot) unit 704. Composed. The control unit 611 controls the switch (SW) 612 according to the channel information of the currently received data channel DPCH. That is, if the channel information of the currently received data channel DPCH is the TPC unit 702, the switch (SW) 612 is controlled to select the output of the TPC phase estimation unit 601, and the data (Data) unit 703 If there is, the switch (SW) 612 is controlled so as to select the output of the data phase estimation unit 602, and the phase estimation value used for synchronous detection is switched.

  The complex multiplier 613 corrects the TPC and data (Data) input from the DPCH despreading unit 104 using the phase estimation value selected and output by the switch (SW) 612. The detection result is output to the RAKE combining unit 107.

  Next, a phase estimation method for the TPC part and data (Data) part in the data channel DPCH will be described with reference to FIG. FIG. 8 is a diagram for explaining phase estimation sections for TPC and Data.

  In FIG. 7, when the downlink TPC section 702 is demodulated, it is necessary to reflect the uplink transmission power based on the result of TPC demodulation at the leading timing of the uplink slot after 512 chips. Therefore, when TPC demodulation is performed, it is difficult to perform phase estimation using the future common pilot channel CPICH because it is not in time to reflect the uplink transmission power. Therefore, the phase estimation section for TPC is as shown in FIG.

  On the other hand, in the demodulation of the data (Data) unit 703, the time regulation is not strict as in the TPC unit 702, so that phase estimation can be performed using the future common pilot channel CPICH, and the demodulation characteristic can be improved. . Therefore, the phase estimation section for data (Data) is a period longer than the phase estimation section for TPC (FIG. 8A), as shown in FIG. 8B.

  As described above, in the second embodiment, the phase estimation value for TPC demodulation and the phase estimation value for data demodulation can be obtained separately and synchronously detected separately, so that reception characteristics can be improved. it can.

  In each of the embodiments described above, DPCH is shown as the data channel, but other channels such as SCCPCH may be used.

  INDUSTRIAL APPLICABILITY The present invention is useful as a phase estimation device, a phase estimation method, and a reception device that improve reception performance when receiving a diversity pilot transmission pattern of a common pilot channel that conforms to the mobile communication standard 3GPP TS25.211.

The block diagram which shows the structure of a receiver provided with the phase estimation apparatus which concerns on Embodiment 1 of this invention. A diagram showing a 4-symbol phase estimation period with transmit diversity (when frame offset is odd) A diagram showing a 4-symbol phase estimation period with transmit diversity (when the frame offset is an even number) The figure explaining the characteristic deterioration principle when the addition average section is not symmetrical Diagram showing 6 symbol phase estimation period with transmit diversity (when frame offset is odd) Diagram showing 6-symbol phase estimation period with transmit diversity (when frame offset is even) The block diagram which shows the structure of a receiver provided with the phase estimation apparatus which concerns on Embodiment 2 of this invention. The block diagram which shows the structural example of the phase estimation part and synchronous detection part which are shown in FIG. The figure explaining TPC demodulation and uplink timing The figure explaining the phase estimation area for TPC and Data The figure which shows the diversity transmission pattern of the common pilot channel defined by the mobile communication standard 3GPP TS25.211

Explanation of symbols

100, 500 Receiving device including phase estimation device 101 Antenna 102 Radio receiving unit 103 CPICH despreading unit 104 DPCH despreading unit 105, 501 Phase estimation unit 106, 502 Synchronous detection unit 107 RAKE combining unit 108 Decoding unit 109 , 503 Control unit 601 TPC phase estimation unit 602 Data phase estimation unit 611 Control unit 612 Switch (SW)
613 Complex multiplier

Claims (8)

  A phase estimation apparatus comprising: control means for changing a size of an addition average section for each radio link; and phase estimation means for calculating a phase estimation value in the changed addition average section.   2. The phase estimation apparatus according to claim 1, wherein the control means changes the size of the addition average interval according to a timing difference between a data channel and a pilot channel.   Control means for generating channel information of the data channel being received, and phase estimation means for receiving the channel information and calculating phase estimation values for each of the various data in the data channel to be received using different averaging intervals And a phase estimation apparatus.   Control means for generating channel information of the data channel being received, and phase estimation that receives the channel information and calculates phase estimation values for various data in the data channel to be received using different addition average sections And a synchronous detection means that receives the channel information and selects a phase estimation value to be used according to data to be synchronously detected from a plurality of phase estimation values calculated by the phase estimation means. A receiving device.   The phase estimation means calculates a phase estimation value for TPC in the received data channel, and the synchronous detection means calculates the TPC phase calculated by the phase estimation means when demodulating the TPC in the received data channel. The receiving apparatus according to claim 4, wherein an estimated value is used.   A phase estimation method comprising: a control step of changing and controlling the size of an addition average interval for each radio link; and a phase estimation step of calculating a phase estimation value in the changed addition average interval.   7. The phase estimation method according to claim 6, wherein, in the control step, the size of the addition average interval is changed according to a timing difference between the data channel and the pilot channel.   A control step for generating channel information of the data channel being received, and receiving the channel information, and calculating phase estimation values for various types of data in the data channel being received using different addition average intervals, respectively. A phase estimation step.

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