JP2005079836A - Receiver and reception method to be used for w-cdma radio communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver of a W-CDMA system by properly judging whether an antenna diversity system has been applied to a received signal from a communication base station and carrying out reception/demodulation processing by a system adapted to the result. <P>SOLUTION: The receiver of the W-CDMA system is provided with: a plurality of CPICH reception parts corresponding to each of a plurality of antennas on a transmission side; a plurality of SCH reception parts for demodulating SCH by using a propagation path estimation value obtained by each CPICH reception part; a judging part for judging whether an STTD system is applied to the CCPCH of the received signal on the basis of the SCH demodulated by the SCH reception parts; and a CCPCH demodulation part which demodulates CCPCH by using a propagation path estimated value obtained by each CPICH reception part and further performs STTD demodulation processing to the CCPCH when judging that the STTD system has been applied to the CCPCH. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus and its receiving method used in a wireless communication system using a W-CDMA (Wideband Code Division Multiple Access) method, and more particularly to a transmission diversity method such as an STTD method or a TSTD method. The present invention relates to a receiving apparatus suitable for used communication and a receiving method thereof.

  CDMA is a wireless communication system that multiplies multiple carriers with different codes and multiplexes them, and then transmits and receives using spread spectrum communication technology of the direct spreading method. It is resistant to multipath fading and noise and has good communication quality. Thus, it has characteristics that frequency utilization efficiency is good, high-speed data communication is possible, and communication confidentiality is high.

  Currently, the CDMA system is used for wireless communication such as mobile phones, and in Japan, it has been put into practical use in NTT DOCOMO's FOMA (registered trademark), and is a standardization project for third-generation mobile communication systems. 3GPP (3rd Generation Partnership Project) is standardized as a global standard in third-generation mobile communication.

In 3GPP, a downlink physical channel is defined in TS25.211 5.3, and TS25.214 Annex C shows an example of a procedure related to cell search. ("TS (Technical Specification)" means technical specifications. The same applies to the following.)
The purpose of the cell search process is to identify the scrambling code of a communicable cell. Cell scrambling codes are divided into code groups, which are described in detail in TS 25.213 5.2.2.

  According to TS25.214 Annex C of 3GPP, cell search is roughly divided into three stages, and slot synchronization is performed as step 1, frame synchronization and code group identification are performed as step 2, and scrambling code identification is performed as step 3. Has been.

  Here, in the downlink, which is transmission from a radio communication base station to a mobile station (radio communication terminal), transmission data has a radio frame structure, and a 10 ms section is divided into one radio frame, and one radio frame is # It is defined to be composed of 15 slots from 0 to # 14.

  In step 1 of the cell search in the mobile station, the correlation start of the primary SCH (Synchronization Channel) inserted at the head of each slot included in the radio frame is performed, and the slot head timing is detected by obtaining the correlation timing. And take slot synchronization. (Primary SCH is hereinafter abbreviated as “P-SCH”.)

  In step 2 of the cell search in the mobile station, a sequence defined in TS25.213 5.2.3 using a secondary SCH (hereinafter abbreviated as “S-SCH”) at the slot head timing obtained in step 1. Is searched for (frame synchronization), and a code group is identified.

  In step 3 of the cell search in the mobile station, a primary CPICH (Common Pilot Channel) is used for each Scramble code assigned to the code group identified in step 2 at the frame head timing obtained in step 2. By performing correlation calculation, the scrambling code of the currently searched cell is identified. (Hereinafter, Primary CPICH is abbreviated as “P-CPICH”.)

  In step 3, primary CCPCH (Common Control Physical Channel: common control physical channel) is demodulated, and CRC is confirmed to confirm the searched scrambling code. (Hereinafter, Primary CCPCH is abbreviated as “P-CCPCH”.)

  By the way, in the downlink, a transmission diversity scheme in which data is transmitted using two antennas is applied. As the transmission diversity method, STTD (Space Time block coding based antenna diversity: Space Time Transmit Diversity), TSTD (Time Switched Transmit Diversity), and closed-loop standardization methods are used.

In the STTD system, the same transmission data is encoded and transmitted from two antennas at the same time, thereby mitigating fluctuations in the level of received data. The details are described in 3GPP TS25.211 5.3.1.1. Stipulated in .2.
The TSTD system switches transmission antennas for each slot of a radio frame, and details thereof are defined in 3GPP TS25.211 5.3.3.5.1.

  Which transmission diversity method is applied to each downlink physical channel is defined in TS 25.211 5.3.1 of 3GPP. This rule is shown in the table below. In the table, the symbol “x” indicates that it is applicable, and the symbol “-” indicates that it is not applicable. In addition, SCH is assumed to include both P-SCH and S-SCH.

  According to 3GPP TS25.211 5.3.3.2.3.1, whether to apply STTD scheme to P-CCPCH is based on indication by higher layer message, demodulated SCH, or both Is to be judged. In the initial cell search immediately after the power is turned on, no upper layer message is received. Therefore, whether to apply the STTD method when demodulating the P-CCPCH in step 3 is determined based on the demodulation result of the SCH. Become.

  Further, according to TS25.211 5.3.3.1, when the transmission diversity scheme is applied in the downlink, different CPICHs are transmitted from antenna 1 and antenna 2, respectively. These two types of CPICHs are multiplied by patterns that are orthogonal as data, similar to OTD (Orthogonal Transmit Diversity).

  Implementing a transmit diversity system can improve performance, but requires two antennas, which increases the installation cost of communication base stations. Therefore, in wireless communication systems, transmit diversity is implemented in all communication base stations. Instead, a configuration may be adopted in which a communication base station that is mounted and a communication base station that is not mounted are mixed.

  As described above, since the upper layer message is not received at the initial cell search immediately after power-on in the mobile station, when demodulating the P-CCPCH in step 3, it is based on the demodulated SCH data. Therefore, it is determined whether to apply the STTD scheme to the P-CCPCH.

  FIG. 9 is a diagram schematically showing a configuration example of an SCH demodulator in a conventional mobile station (wireless communication terminal). In this example, the demodulation method by general TSTD is used for demodulation of SCH. In addition, the demodulation device shown in FIG. 9 is normally configured as a part of a reception processing device of a wireless communication terminal that is a mobile station.

  In FIG. 9, the demodulator includes pilot channel receivers 910 and 920, an SCH receiver 930, a selector 941, a controller 942, and a complex conjugate calculator 943.

  The pilot channel receiving unit is for receiving CPICH, and is installed corresponding to the number of transmitting antennas on the transmitting side (communication base station). In this example, according to the 3GPP standard, two pilot channel receivers 910 and 920 are provided corresponding to two transmitting antennas (transmitting antennas 1 and 2) on the transmitting side.

The operation when a baseband signal is input to the SCH demodulator configured as shown in FIG. 9 will be described below.
In pilot channel receiving section 910, despreading section 911 performs complex despreading by applying a scrambling code to the input signal. Since CPICH is used here, the channelization code No. Since it is “0”, it is not necessary to use it. The signal subjected to complex despreading by the despreading unit 911 is subjected to integration processing for one symbol section and then output to the propagation path estimation unit 912.

  The propagation path estimation unit 912 multiplies the input signal by a symbol pattern assigned to each antenna, and then performs integration processing over several symbols (even number symbols are desirable to maintain orthogonality between antennas). (Averaging process) is performed. The result is analyzed, and a propagation path estimation value obtained by estimating the propagation path of the signal transmitted from the transmission antenna 1 is output to the selection unit 941.

  In pilot channel receiving section 920, despreading section 921 performs complex despreading by applying a scrambling code to the input signal. Since CPICH is used here, the channelization code No. Since it is “0”, it is not necessary to use it. The signal subjected to complex despreading by the despreading unit 921 is subjected to integration processing for one symbol section and then output to the propagation path estimation unit 922.

  In propagation path estimation section 922, the input signal is multiplied by a symbol pattern assigned to each antenna, and then integrated over several symbols (an even number of symbols is desirable to maintain orthogonality between antennas). (Averaging process) is performed. The result is analyzed, and a propagation path estimation value obtained by estimating the propagation path of the signal transmitted from the transmission antenna 2 is output to the selection unit 941.

  In SCH receiving section 930, despreading section 931 performs orthogonal despreading by applying an SCH code to the input signal. According to the 3GPP specification, the scrambling code of the SCH part is masked, and no channelization code is used. Therefore, it is only necessary to multiply the SCH code. The signal despread by the despreading unit 931 is subjected to integration processing for one symbol section and then output to the multiplication unit 932. When both P-SCH and S-SCH are used, the result of adding both the in-phase component and the quadrature component of the quadrature despread results is output.

  The selection unit 941 selects any one of the propagation path estimation values output from the pilot channel reception units 910 and 920 and outputs the selected value to the complex conjugate calculation unit 943. The control unit 942 generates a control signal for selecting the output from the pilot channel receiving units 910 and 920 in the selection unit 941 in units of time switching periods in synchronization with the reference time of the communication base station. Output to.

  In complex conjugate calculation section 943, the complex conjugate value of the propagation path estimation value input from selection section 941 is calculated and output to multiplication section 932. The multiplier 932 multiplies the signal input from the despreader 931 by the complex conjugate value input from the complex conjugate calculator 943 and outputs the result as an output signal of the present demodulator. The synchronous detection is realized by the multiplication processing in the multiplication unit 932.

  Here, the control unit 942 selectively provides the channel estimation values from the pilot channel receiving units 910 and 920 to the SCH receiving unit 930 through the selecting unit 941 based on the clock information synchronized with the communication base station. However, it is assumed that the mobile station acquires a switching pattern, a cycle, and the like according to the 3GPP standard.

  The SCH demodulated signal obtained by the SCH demodulating apparatus is subjected to averaging processing and the like, and then the data on which the SCH is superimposed is determined, and whether or not the STTD scheme is applied to the P-CCPCH is determined. I do.

The details of the transmission diversity method described above are described in “Time Switching Transmission Diversity Device and Method for Mobile Communication System” of Patent Document 1. Patent Document 1 describes a case where OTD is used as a pilot channel, but the same operation can be realized not only by OTD but also by using the above-described CPICH multiplied by a pattern orthogonal to data.
JP 2000-514992 A.

  According to the above-described conventional SCH demodulator, when a transmission diversity scheme such as the TSTD scheme is applied to a transmission signal from a communication base station, the time switching process synchronized with the transmission side is performed appropriately. Can be received.

  However, as described above, the antenna diversity scheme is not implemented in all communication base stations. In addition, the mobile station cannot know in advance whether the antenna diversity scheme is implemented in the communication base station that is to perform communication. For this reason, when performing the SCH demodulation processing, there is no means for determining in advance whether or not the received signal should be processed by the TSTD method.

  The TSTD scheme is a scheme in which a transmission base station having a plurality of antennas performs transmission by switching a transmission antenna for each slot of a radio frame. Therefore, accurate reception processing according to application / non-application of the TSTD scheme must be performed. In this case, the transmitted data cannot be completely received.

For example, in a conventional SCH demodulator supporting the above-described TSTD scheme, if communication is started with a communication base station that does not implement the antenna diversity scheme, the signal from the antenna 1 in the even slot and the signal from the antenna 2 in the odd slot Because of the operation of performing demodulation processing with time switching to receive, the odd-numbered slot will be demodulated at all, and the result will be used for averaging processing, so it is actually transmitted. Only half of the signal of the antenna 1 is used, and a noise component is used for the other half. As a result, the characteristics of the received signal are significantly deteriorated.
As a result, the accuracy of the P-CCPCH determination process application / non-application determination process performed using the SCH demodulation result is also significantly reduced.

  The present invention has been made in view of such a situation, and is a receiving apparatus (mobile station) used for W-CDMA wireless communication, in which an antenna diversity method is applied to a received signal from a communication base station. It is an object of the present invention to provide a receiving apparatus capable of appropriately determining whether or not the data is received and performing the receiving process and the demodulating process using a method adapted to the result.

  The receiving apparatus used for W-CDMA wireless communication according to the present invention is particularly intended to improve the demodulation characteristics of SCH, and to improve the accuracy of subsequent P-CCPCH STTD method application / non-application determination processing. To do.

  As a result of diligent research in view of the above-described problem, the present inventor has provided a plurality of SCH demodulation processing systems in the receiving apparatus, and from among the SCH demodulation processing systems regardless of whether the TSTD scheme is applied to the SCH. It was conceived that the SCH demodulation characteristics can be improved by appropriately selecting the input signal.

  That is, the present invention includes a plurality of CPICH receivers corresponding to each of a plurality of antennas provided on the transmission side, a plurality of SCH receivers that demodulate the SCH using propagation path estimation values obtained in each CPICH receiver, A selection / combination unit that selects and combines one or more of the SCHs demodulated by the plurality of SCH reception units at a predetermined timing, and a CCPCH of the received signal based on the SCH that is combined by the selection / combination unit. An STTD application determining unit that determines whether or not the STTD scheme is applied, and a CCPCH demodulated using a propagation path estimation value obtained in each CPICH receiver, and the STTD scheme is applied to the CCPCH in the STTD application determining unit If it is determined that the CCPCH is STCCP demodulated, the CCPCH There is provided a receiving apparatus of the W-CDMA system, comprising: a tone portion.

  In the W-CDMA reception apparatus of the present invention, the selection / combination unit always uses one SCH among the SCHs demodulated by the plurality of SCH reception units, and selectively uses another SCH. And synthesizing.

  In the W-CDMA receiving apparatus of the present invention, the SCH that is always used in the selection / combination unit is a SCH that is demodulated for a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. It is characterized by that.

  As a result, the communication base station does not fail to receive the transmitted SCH regardless of whether the transmission diversity method is applied or not, and the propagation path used only when the transmission diversity method is applied. By selectively applying, it is possible to prevent even noise components from being demodulated.

In the W-CDMA receiving apparatus of the present invention, the selecting / combining unit selects and combines the SCH for each slot included in the received frame.
In the W-CDMA receiver according to the present invention, the selection / combination unit further selects and combines SCHs depending on whether the received frame is an even-numbered slot or an odd-numbered slot. And

  When the TSTD scheme is applied to the transmission of the SCH from the communication base station, since the transmission antenna is switched for each slot of the radio frame, the transmission is used for each slot in the receiving apparatus in this way. By switching the path, the SCH can be reliably received.

  In the present invention, a plurality of CPICH receiving units corresponding to each of a plurality of antennas provided on the transmitting side and propagation path estimation values obtained in each CPICH receiving unit are selected and combined at a predetermined timing. The selection / combination unit, the SCH reception unit that demodulates the SCH using the propagation path estimation value synthesized in the selection / combination unit, and the CCPCH of the reception signal based on the SCH demodulated in the SCH reception unit An STTD application determination unit that determines whether or not a scheme is applied, and a CCPCH demodulated using a propagation path estimation value obtained in each CPICH receiver, and the STTD scheme is applied to the CCPCH in the STTD application determination unit And a CCPCH demodulator that performs STTD demodulation on the CCPCH, There is provided a receiving apparatus of the W-CDMA system with.

  In the W-CDMA receiving apparatus of the present invention, the selecting / combining unit always uses one propagation path estimated value among the propagation path estimated values obtained in each CPICH receiving section, and performs other propagation path estimation. The composition is performed by selectively using the values.

  In the W-CDMA receiver of the present invention, the propagation path estimation value that is always used in the selection / combination unit is an estimation value of a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. It is characterized by being.

  As a result, the communication base station does not fail to receive the transmitted SCH regardless of whether the transmission diversity method is applied or not, and the propagation path used only when the transmission diversity method is applied. By selectively applying, it is possible to prevent even noise components from being demodulated.

In the W-CDMA receiving apparatus of the present invention, the selecting / combining unit selects and combines the propagation path estimation values for each slot included in the received frame.
In the W-CDMA system receiver of the present invention, the selection / combination unit selects and combines the propagation path estimation values depending on whether the received frame is an even-numbered slot or an odd-numbered slot. Features.

  When the TSTD scheme is applied to the transmission of the SCH from the communication base station, since the transmission antenna is switched for each slot of the radio frame, the transmission is used for each slot in the receiving apparatus in this way. By switching the path, the SCH can be reliably received.

  In the W-CDMA receiver according to the present invention, the CCPCH demodulator starts operating simultaneously with the SCH receiver. Further, the CCPCH demodulation unit performs STTD demodulation processing on the CCPCH until a determination result is obtained by the STTD application determination unit.

  This is because the time required for the cell search is shortened by starting the P-CCPCH demodulation processing without waiting for the P-CCPCH STTD application determination processing by SCH demodulation. Note that while it is unclear whether the STTD scheme is applied to the P-CCPCH, if the P-CCPCH demodulation processing is performed with the setting when the STTD scheme is applied, the degradation can be relatively reduced.

  In the W-CDMA receiving apparatus of the present invention, when the characteristics of the CCPCH demodulated by the CCPCH demodulator do not satisfy a predetermined standard, the CCPCH demodulator extends the demodulation process.

  As a result, if the P-CCPCH demodulation process is performed with an incorrect setting for STTD application without waiting for the P-CCPCH STTD application determination process by SCH demodulation, the corresponding demodulation process is extended. , Performance degradation of P-CCPCH demodulation processing can be compensated.

  The extension of the P-CCPCH demodulation process is the same as the length of the received signal required for the determination process by the STTD application determination unit, or the CCPCH demodulation unit is the same as the time required for the determination process by the STTD application determination unit. , To do.

  In the W-CDMA receiving apparatus of the present invention, if the demodulated CCPCH characteristics do not satisfy a predetermined standard even if the above-described CCPCH demodulation processing is extended, the following measures can be taken. . That is, when the STTD application determining unit determines that the STTD scheme is applied to the CCPCH, the CCPCH demodulating unit demodulates the CCPCH without applying the STTD demodulation process, and the STTD application determining unit performs the CCPCH. When it is determined that the STTD scheme is not applied to the CCPCH, the CCPCH demodulation unit demodulates the CCPCH by applying the STTD demodulation process.

  As a result, if the ST-D application determination process for P-CCPCH by SCH demodulation is incorrect, the P-CCPCH demodulation process is performed again with the correct settings. Time wasted.

The W-CDMA receiving apparatus of the present invention is characterized in that an offset is provided in the determination criterion by the STTD application determination unit.
By appropriately setting this offset amount, it is possible to reduce the amount of degradation caused by an error in the PTDP determination process of P-CCPCH due to SCH demodulation on the P-CCPCH demodulation process.

  In the W-CDMA receiving apparatus of the present invention, the determination reference offset amount is determined based on an SCH received electric field strength, a CPICH received electric field strength, or a CCPCH received electric field strength.

In this way, by adaptively changing the offset amount of the determination criterion according to the propagation path condition, it is possible to further reduce the probability of an error in the ST-D application determination process for P-CCPCH due to SCH demodulation.
In the W-CDMA system receiver of the present invention, the determination reference offset is shifted to the STTD system application side.

  In general, when P-CCPCH demodulation is applied erroneously while STTD scheme is applied rather than when P-CCPCH demodulation is applied when STTD scheme is not applied but erroneously applied. Since the demodulated signal is more deteriorated, it is preferable to offset the threshold of the STTD application determination process to the STTD system application side.

  The present invention is also a method for determining whether or not the STTD scheme is applied to the CCPCH of a received signal in a W-CDMA scheme receiver, wherein each propagation path estimation value of a plurality of antennas provided on the transmission side is determined. A step of calculating using the received CPICH, a step of demodulating the SCH in a plurality of systems using the calculated propagation path estimated values, and selecting one or more of the SCH demodulated in the plurality of systems at a predetermined timing And a step of determining whether the STTD scheme is applied to the CCPCH of the received signal based on the selected and combined SCH.

  In the method of the present invention, in the selecting and combining step, combining one of the SCHs demodulated in the plurality of systems always using one SCH and selectively using another SCH, To do.

  In the method of the present invention, the SCH that is always used in the selecting and combining step is characterized in that the SCH that is always used for transmission is demodulated regardless of the number of transmission antennas provided on the transmission side.

In the method of the present invention, in the selecting and combining step, the SCH is selected and combined for each slot included in the received frame.
In the method of the present invention, in the selecting and combining step, the SCH is selected and combined depending on whether it is an even-numbered slot or an odd-numbered slot in a received frame.

  The present invention is also a method for determining whether or not the STTD scheme is applied to the CCPCH of a received signal in a W-CDMA scheme receiver, wherein each propagation path estimation value of a plurality of antennas provided on the transmission side is determined. A step of calculating using the received CPICH, a step of selecting and combining one or more of the calculated propagation path estimated values at a predetermined timing, and a SCH using the propagation path estimated value selected and combined And a step of determining whether the STTD scheme is applied to the CCPCH of the received signal based on the demodulated SCH.

  In the method of the present invention, in the selecting and combining step, among the calculated propagation path estimated values, one propagation path estimated value is always used, and another propagation path estimated value is selectively used, It is characterized by performing synthesis.

In the method of the present invention, the propagation path estimation value that is always used in the selecting and combining step is an estimation value of a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. To do.
In the method of the present invention, the selecting and synthesizing step is characterized by selecting and synthesizing a propagation path estimated value for each slot included in the received frame.

  In the method of the present invention, in the selecting and combining step, propagation path estimation values are selected and combined depending on whether the slot is an even-numbered slot or an odd-numbered slot in the received frame.

  The present invention also provides a program for determining whether or not the STTD scheme is applied to the CCPCH of a received signal in accordance with the above-described method in a W-CDMA receiver.

  As described above, according to the receiving apparatus used for W-CDMA wireless communication of the present invention, the demodulation characteristics of the SCH are improved regardless of whether the TSTD method is applied to the SCH. The accuracy of the P-CCPCH STTD method application / non-application determination process to be used is improved.

  The best mode for carrying out the apparatus and method of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 8 are diagrams illustrating embodiments of the present invention. In these drawings, the same reference numerals denote the same components, and the basic configuration and operation are the same. To do.

[First embodiment of receiving apparatus]
FIG. 1 is a functional block diagram schematically showing an internal configuration of a demodulation processing mechanism in a first embodiment of a receiving apparatus (mobile station) used for W-CDMA wireless communication according to the present invention.

  The receiving apparatus illustrated in FIG. 1 includes a first CPICH receiving unit 110 that performs propagation path estimation corresponding to the transmission antenna 1 of the communication base station, and a second CPICH reception unit 120 that performs propagation path estimation corresponding to the antenna 2. First SCH receiver 130 that performs synchronous detection of SCH transmitted from antenna 1, Second SCH receiver 140 that performs synchronous detection of SCH transmitted from antenna 2, and P-CCPCH demodulation of the received signal P-CCPCH demodulator 150, complex conjugate calculators 161 and 162 for calculating complex conjugates for the output signals from first and second CPICH receivers 110 and 120, respectively, and second SCH A first selection unit 163 that switches an input signal from the reception unit 140, an input signal from the first SCH reception unit 130, an input signal from the selection unit 163, and A combining unit 164 that combines, an averaging processing unit 165 that performs an averaging process on the input signal from the combining unit 164, and an STTD that determines whether to apply the STTD scheme to the P-CCPCH using the input signal from the averaging processing unit 165 An application determination unit 166, a control unit 167 that controls the first selection unit 163 and the second selection unit 168, and a second selection unit 168 that switches an input signal from one output of the P-CCPCH demodulation unit 150. And an STTD decoding unit 169 that performs STTD decoding of input signals from the P-CCPCH demodulation unit 150 and the second selection unit 168.

  The first CPICH reception unit 110 includes a despreading unit 111 and a propagation path estimation unit 112, and the second CPICH reception unit 120 includes a despreading unit 121 and a propagation path estimation unit 122.

  The first SCH receiver 130 includes a despreader 131 and a multiplier 132 for synchronous detection, and the second SCH receiver 140 includes a despreader 141 and a multiplier 142 for synchronous detection. Contains.

  The P-CCPCH demodulation unit 150 includes two systems of despreading units and multiplication units, that is, a despreading unit 151-a and a multiplication unit 152-a, and a despreading unit 151-b and a multiplication unit 152-b. Yes.

  In FIG. 1, each of the first CPICH receiving unit 110, the second CPICH receiving unit 120, the first SCH receiving unit 130, the second SCH receiving unit 140, and the P-CCPCH demodulating unit 150 is illustrated. It is assumed that a complex signal converted to a baseband from a signal received by an antenna of the present receiving apparatus is input as an input signal.

Next, the operation of demodulating the received signal in the receiving apparatus of the present embodiment will be described in detail.
Here, the STTD scheme application determination is performed after the completion of the Scramble code identification, which is the first half of step 3 of the cell search according to the 3GPP standard described above as the prior art, and the P-CCPCH demodulation is performed. Will be described.

  First, the signals input to the first SCH receiver 130 and the second SCH receiver 140 are despread by the despreaders 131 and 141, respectively. For this despreading process, the P-SCH code used in step 1 of the cell search may be used. Alternatively, since the same data modulation is performed on the S-SCH, the despreading units 131 and 141 may be configured to combine and output the correlation results of both the P-SCH and the S-SCH. Since the cell search step 2 has already been performed, the S-SCH code and timing are already known. Further, this despreading is complex despreading, and a complex signal is output.

  Since the despreading units 131 and 141 are intended for demodulation of the SCH, only the despreading result of the portion related to the SCH in the input signal is output, and the despreading result is output at the timing when the SCH is not included. Shall not be. Further, this function is not necessarily realized by the despreading units 131 and 141, and may be performed by any one of the subsequent processing units.

  Further, since the despreading units 131 and 141 operate with the same reference code and the same timing for the same input signal, the same output is obtained as a result. For this reason, the despreading units 131 and 141 may be unified into one despreading unit, and the output may be distributed to the multipliers 132 and 142 for synchronous detection.

  On the other hand, the signals input to the first CPICH receiving unit 110 and the second CPICH receiving unit 120 are despread by the despreading units 111 and 121 using the reference code corresponding to the CPICH. This despreading is complex despreading, and a complex signal is output.

  Output signals from the despreading units 111 and 121 are input to the propagation path estimation units 112 and 122, respectively, and averaged to estimate the propagation path. Here, the propagation path estimation unit 112 simply performs processing such as addition averaging or exponential weighting averaging, and the propagation path estimation unit 122 uses CPICH transmitted from the antenna 2 of the communication base station, so that symbol pattern correction is performed. After performing the above, processing such as addition averaging or exponential weighting averaging similar to the above is performed. Here, as a matter of course, the roles of the propagation path estimation units 112 and 122 may be interchanged.

  The propagation path estimation value output from the propagation path estimation unit 112 is subjected to a complex conjugate value by the complex conjugate calculation unit 161, and is output to the multiplication units 132 and 152-a. The propagation path estimation value output from the propagation path estimation unit 122 is subjected to a complex conjugate value by the complex conjugate calculation unit 162 and output to the multiplication units 142 and 152-b.

  Again, in first SCH receiving section 130, multiplication section 132 multiplies the input signal from despreading section 131 and the input signal from complex conjugate calculation section 161 to obtain a synchronous detection output. At this time, since the input signal from the complex conjugate arithmetic unit 161 is multiplied while the CPICH amplitude information from the antenna 1 of the communication base station remains, weighting of maximum ratio combining is simply performed. .

  Further, in second SCH receiving section 140, multiplication section 142 multiplies the input signal from despreading section 141 and the input signal from complex conjugate calculation section 162 to obtain a synchronous detection output. At this time, since the input signal from the complex conjugate arithmetic unit 162 is multiplied while the CPICH amplitude information from the antenna 2 of the communication base station remains, weighting of maximum ratio combining is simply performed. .

  An output signal from the multiplication unit 142 is input to the first selection unit 163. The selection unit 163 realizes a switch function for selecting whether to output an input signal to the synthesis unit 164 or not. Whether to output an input signal is determined by the slot number. That is, in the receiving apparatus according to the present embodiment, only the input signal at the timing corresponding to the odd slot number is output among the slot numbers 0 to 14 in the radio frame, and the input signal at the timing corresponding to the even slot number is output. It is supposed not to. Such timing control is controlled by the control unit 167.

  The output signal from the multiplication unit 132 and the output signal from the first selection unit 163 are input to the synthesis unit 164. The synthesizer 164 simply adds these signals. By this addition processing, when it is unclear whether the TSTD scheme is applied, it is possible to cope with an SCH signal in an odd slot in which it is not known which of the two antennas of the communication base station is transmitted.

  The output signal from the synthesis unit 164 is input to the averaging processing unit 165, and the averaging process is performed for a certain time. This averaging process is generally used to improve performance, and any method such as addition average or exponential weighting average may be used.

  An output signal from the averaging processing unit 165 is input to the STTD application determination unit 166. The STTD application determining unit 166 determines whether or not the STTD encoding of P-CCPCH is applied to the input signal. That is, according to the 3GPP standard, data superimposed on the SCH is acquired from the input signal. If this is “+1”, the STTD scheme is applied to the P-CCPCH, and if it is “−1”, the STTD scheme is not applied. It will be. The STTD application determination unit 166 outputs the STTD application determination result to the control unit 167.

  In the receiving apparatus according to the present embodiment, after determining whether the STTD scheme is applied to the P-CCPCH as described above, the P-CCPCH demodulating unit 150 and later perform P-CCPCH demodulation processing. It has become.

  The signal input to the P-CCPCH demodulation unit 150 is subjected to complex despreading processing in the despreading units 151-a and 151-b. It is assumed that the operation start timing information, the scrambling code to be used, and the channelization code information are known by the cell search already performed, and complex despreading processing is performed using these information. (Here, the description of the control path is omitted.) Further, the despreading in the despreading units 151-a and 151-b is complex despreading, and a complex signal is output.

  An output signal from the despreading unit 151-a is input to the multiplication unit 152-a. Multiplication section 152-a multiplies the input signal from despreading section 151-a and the input signal from complex conjugate calculation section 161 to obtain a synchronous detection output. Here, since the input signal from the complex conjugate calculation unit 161 is the complex conjugate value of the propagation path estimation value calculated using the CPICH from the antenna 1 of the communication base station in the first CPICH reception unit 110, Weighting for ratio synthesis will be performed. Note that the processing in the multiplication unit 152-a is the same as the processing in the multiplication unit 132 described above.

  The output signal from the despreading unit 151-b is input to the multiplication unit 152-b. Multiplication section 152-b multiplies the input signal from despreading section 151-b and the input signal from complex conjugate calculation section 162 to obtain a synchronous detection output. Here, since the input signal from the complex conjugate calculation unit 162 is a complex conjugate value of the propagation path estimation value calculated by using the CPICH from the antenna 2 of the communication base station in the second CPICH receiving unit 120, the maximum Weighting for ratio synthesis will be performed. The processing in the multiplication unit 152-b is the same as the processing in the multiplication unit 142 described above.

  Here, multiplication sections 152-a and 152-b use the propagation path estimation results of antenna 1 and antenna 2 obtained in first CPICH reception section 110 and second CPICH reception section 120, respectively. However, you may make it acquire from the CPICH receiving part installed separately instead of these CPICH receiving parts.

  An output signal from the multiplication unit 152-b is input to the second selection unit 168. In accordance with an instruction from the control unit 167, the second selection unit 168 switches between outputting the input signal as it is or outputting “0”. Which is output is determined according to the STTD application determination in the STTD application determination unit 166. That is, the second selection unit 168 outputs the input signal as it is when the STTD method is applied, and outputs “0” when the STTD method is not applied.

  The output signal from the multiplication unit 152-a and the output signal from the second selection unit 168 are input to the STTD decoding unit 169 and subjected to STTD decoding processing. The STTD decoding unit 169 always performs STTD decoding processing on the input signal. When the input signal from the selection unit 168 is “0”, the STTD decoding processing is not performed as a result. Is operating to produce the same output.

  In the above description, the combination of the output from the second selection unit 168 and the STTD decoding unit 169 realizes a function of switching whether to apply the STTD decoding process. The configuration is merely an example, and the receiving apparatus according to the present embodiment can take various apparatus configurations with regard to the switching function to which STTD decoding processing is applied / not applied.

  According to the receiving apparatus of the present embodiment described above, by appropriately determining whether the TSTD scheme is applied to the SCH and appropriately selecting an input signal from the two SCH demodulation processing systems, SCH demodulation characteristics can be improved. As a result, the accuracy of the P-CCPCH STTD method application / non-application determination process using the SCH demodulated data is improved.

[Second embodiment of receiving apparatus]
FIG. 2 is a functional block diagram schematically showing an internal configuration of a demodulation processing mechanism in a second embodiment of a receiving apparatus (mobile station) used for W-CDMA wireless communication according to the present invention.
2 includes a first CPICH receiving unit 110 that performs propagation path estimation corresponding to the transmission antenna 1 of the communication base station, and a second CPICH reception unit 120 that performs propagation path estimation corresponding to the antenna 2. , For the output signals from the SCH receiver 130 that performs synchronous detection of the SCH, the P-CCPCH demodulator 250 that performs P-CCPCH demodulation of the received signal, and the first and second CPICH receivers 110 and 120, The complex conjugate calculation units 161 and 162 for calculating the complex conjugate, the averaging processing unit 165 for averaging the input signal from the SCH receiving unit 130, and the input signal from the averaging processing unit 165, respectively, P -STTD application determination unit 166 that determines whether to apply the STTD method to the CCPCH, and a control unit 167 that controls the first selection unit 263 and the second selection unit 168. The first selection unit 263 that switches the input signal from the complex conjugate calculation unit 162, the input signal from the first CPICH reception unit 110, and the input signal from the first selection unit 263 are combined to generate an SCH. From the combining unit 264 that outputs to the receiving unit 130, the second selection unit 168 that switches an input signal from one output of the P-CCPCH demodulation unit 250, the P-CCPCH demodulation unit 250, and the second selection unit 168 And an STTD decoding unit 169 that performs STTD decoding of the input signal.

  The first CPICH reception unit 110 includes a despreading unit 111 and a propagation path estimation unit 112, and the second CPICH reception unit 120 includes a despreading unit 121 and a propagation path estimation unit 122.

  In addition, the receiving apparatus according to the present embodiment includes a single SCH receiving unit 130, which is different from that of the first embodiment shown in FIG. The multiplication unit 132 is included.

  Furthermore, in the receiving apparatus of this embodiment, the P-CCPCH demodulation unit 250 includes a single despreading unit 151 and multiplication units 152-a and 152-b branched from the despreading unit 151 into two systems. Yes.

  In FIG. 2, each of the first CPICH receiving unit 110, the second CPICH receiving unit 120, the SCH receiving unit 130, and the P-CCPCH demodulating unit 250 receives a base signal from a signal received by an antenna of the receiving device (not shown). It is assumed that a complex signal converted into a band is input as an input signal.

  Note that the components of the receiving apparatus of the present embodiment shown in FIG. 2 that have the same reference numerals as those of the first embodiment shown in FIG. It operates similarly.

Next, the operation of demodulating the received signal in the receiving apparatus of the present embodiment will be described in detail.
Here, as in the first embodiment, the STTD scheme application determination is performed from the state where the first half of the cell search step 3 according to the 3GPP standard described above as the prior art is completed until the scrambling code identification, An operation for performing demodulation of P-CCPCH will be described.

  First, a signal input to the SCH receiving unit 130 is subjected to despreading processing by the despreading unit 131. For this despreading process, the P-SCH code used in step 1 of the cell search may be used. Alternatively, since the same data modulation is performed on the S-SCH, the despreading unit 131 may be configured to synthesize and output the correlation results of both the P-SCH and the S-SCH. Since the cell search step 2 has already been performed, the code and timing of the S-SCH are known. Further, this despreading is complex despreading, and a complex signal is output.

  Since the despreading unit 131 is intended for demodulating the SCH, only the despreading result of the portion related to the SCH in the input signal is output, and the despreading result is not output at the timing when the SCH is not included. And Further, this function is not necessarily realized by the despreading unit 131, and may be performed by any one of the processing units in the subsequent stage.

  On the other hand, the signals input to the first CPICH receiving unit 110 and the second CPICH receiving unit 120 are despread by the despreading units 111 and 121 using the reference code corresponding to the CPICH. This despreading is complex despreading, and a complex signal is output.

  Output signals from the despreading units 111 and 121 are input to the propagation path estimation units 112 and 122, respectively, and averaged to estimate the propagation path. Here, the propagation path estimation unit 111 simply performs processing such as addition averaging or exponential weighting averaging, and the propagation path estimation unit 122 uses CPICH transmitted from the antenna 2 of the communication base station, so that symbol pattern correction is performed. After performing the above, processing such as addition averaging or exponential weighting averaging similar to the above is performed. Here, as a matter of course, the roles of the propagation path estimation units 112 and 122 may be interchanged.

  The propagation path estimation value output from the propagation path estimation unit 112 is subjected to a complex conjugate value by the complex conjugate calculation unit 161, and is output to the first synthesis unit 264 and the multiplication unit 152-a. The propagation path estimation value output from the propagation path estimation unit 122 is taken as a complex conjugate value by the complex conjugate calculation unit 162, and is output to the first selection unit 263 and the multiplication unit 152-b.

  The first selection unit 263 implements a switch function for selecting whether to output the input signal from the complex conjugate calculation unit 162 to the first synthesis unit 264 or not. Whether to output an input signal is determined by the slot number. That is, in the receiving apparatus according to the present embodiment, only the input signal at the timing corresponding to the odd slot number is output among the slot numbers 0 to 14 in the radio frame, and the input signal at the timing corresponding to the even slot number is output. It is supposed not to. Such timing control is controlled by the control unit 167.

  The output signal from the complex conjugate calculation unit 161 and the output signal from the first selection unit 263 are input to the synthesis unit 264. The synthesizer 264 simply adds these signals and outputs the result to the multiplier 132.

  The multiplier 132 multiplies the input signal from the despreader 131 and the input signal from the first combiner 264 to obtain a synchronous detection output. At this time, since the CPICH amplitude information from the communication base station included in the output signal from the complex conjugate arithmetic unit 161 or 162 is multiplied, the weighting of the maximum ratio combining is simply performed. Will be.

  By such processing, when it is unclear whether the TSTD scheme is applied, it is possible to cope with an SCH signal in an odd slot where it is not known which of the two antennas of the communication base station is transmitted. .

  The output signal from the multiplication unit 132 is input to the averaging processing unit 165, and the averaging process is performed for a certain time. This averaging process is generally used to improve performance, and any method such as addition average or exponential weighting average may be used.

  An output signal from the averaging processing unit 165 is input to the STTD application determination unit 166. The STTD application determining unit 166 determines whether or not the STTD encoding of P-CCPCH is applied to the input signal. That is, according to the 3GPP standard, data superimposed on the SCH is acquired from the input signal. If this is “+1”, the STTD scheme is applied to the P-CCPCH, and if it is “−1”, the STTD scheme is not applied. It will be. The STTD application determination unit 166 outputs the STTD application determination result to the control unit 167.

  In the receiving apparatus according to the present embodiment, after determining whether the STTD scheme is applied to the P-CCPCH as described above, the P-CCPCH demodulating unit 250 and later perform P-CCPCH demodulation processing. It has become.

  The signal input to the P-CCPCH demodulation unit 250 is subjected to complex despreading processing in the despreading unit 151. It is assumed that the operation start timing information, the scrambling code to be used, and the channelization code information are known by the cell search already performed, and complex despreading processing is performed using these information. (Description of the control path is omitted here.) Further, the despreading in the despreading unit 151 is complex despreading, and a complex signal is output.

The output signal from the despreading unit 151 is input to the multiplying units 152-a and 152-b.
Multiplier 152-a multiplies the input signal from despreading section 151 and the input signal from complex conjugate calculation section 161 to obtain a synchronous detection output. Here, since the input signal from the complex conjugate calculation unit 161 is the complex conjugate value of the propagation path estimation value calculated using the CPICH from the antenna 1 of the communication base station in the first CPICH reception unit 110, Weighting for ratio synthesis will be performed.

  Multiplier 152-b multiplies the input signal from despreader 151 and the input signal from complex conjugate calculator 162 to obtain a synchronous detection output. Here, since the input signal from the complex conjugate calculation unit 162 is a complex conjugate value of the propagation path estimation value calculated by using the CPICH from the antenna 2 of the communication base station in the second CPICH receiving unit 120, the maximum Weighting for ratio synthesis will be performed.

  Here, multiplication sections 152-a and 152-b use the propagation path estimation results of antenna 1 and antenna 2 obtained in first CPICH reception section 110 and second CPICH reception section 120, respectively. However, you may make it acquire from the CPICH receiving part installed separately instead of these CPICH receiving parts.

  Further, in the receiving apparatus of this embodiment, the P-CCPCH demodulation unit 250 has a simple configuration in which one despreading unit is omitted as compared with the first embodiment. The overall operation of the unit 250 is exactly the same as that of the P-CCPCH demodulation unit 150 of the first embodiment.

  An output signal from the multiplication unit 152-b is input to the second selection unit 168. In accordance with an instruction from the control unit 167, the second selection unit 168 switches between outputting the input signal as it is or outputting “0”. Which is output is determined according to the STTD application determination in the STTD application determination unit 166. That is, the second selection unit 168 outputs the input signal as it is when the STTD method is applied, and outputs “0” when the STTD method is not applied.

  The output signal from the multiplication unit 152-a and the output signal from the second selection unit 168 are input to the STTD decoding unit 169 and subjected to STTD decoding processing. The STTD decoding unit 169 always performs STTD decoding processing on the input signal. When the input signal from the selection unit 168 is “0”, the STTD decoding processing is not performed as a result. Is operating to produce the same output.

  In the above description, the combination of the output from the second selection unit 168 and the STTD decoding unit 169 realizes a function of switching whether to apply the STTD decoding process. The configuration is merely an example, and the receiving apparatus according to the present embodiment can take various apparatus configurations with regard to the switching function to which STTD decoding processing is applied / not applied.

  In the receiving apparatus of the present embodiment described above, the second SCH receiving unit 140 can be omitted as compared with that of the first embodiment, so that the circuit scale is reduced and the apparatus is reduced in size. I can.

[Operation mode of demodulation processing]
Next, an operation mode in which demodulation processing is performed according to steps 1 to 3 of the 3GPP standard cell search in the receiving apparatuses of the first embodiment and the second embodiment described above will be described with reference to flowcharts.

FIG. 3 is a flowchart showing the flow of demodulation processing in the first mode.
In FIG. 3, first, the receiving apparatus starts a cell search operation as an initial detection operation at power-on or as a communication state detection operation (step 301).

  In step 1, slot timing is detected (step 302). Here, in order to simplify the description, it is assumed that only one path (cell) can be detected. This step may be performed by any method, but generally, the correlation value is obtained using P-SCH, and the timing at which a sufficiently large correlation value is obtained by the internal timing management function is set as the slot timing. Can take the way.

  In step 2, frame synchronization and code group identification are performed based on the slot timing detected in step 302 (step 303). This step may be performed by any method, but generally, a correlation value is obtained using S-SCH, a code group is identified by detecting the sequence, and an internal timing management function is provided. In combination, the frame head timing can be detected.

  In step 3, first, a scrambling code identification process is performed (step 304). Although this step may be performed by any method, in general, the correlation value is obtained for all the scrambling code candidates included in the code group identified in step 303, and the maximum correlation value is obtained and sufficiently large. A correlation value obtained can be determined as a scrambling code.

  In step 3, P-CCPCH demodulation processing is subsequently performed. However, the subsequent processing changes depending on whether or not the STTD scheme is applied to the P-CCPCH of the cell corresponding to the scrambling code identified in step 304. come. As described in the first embodiment and the second embodiment, whether the STTD scheme is applied to the P-CCPCH can be determined by SCH demodulation.

  Therefore, in the receiving apparatus of the present invention, for the first 10 ms (for one frame), the P-CCPCH STTD application determination process (step 305) by the SCH demodulation process and the P-CCPCH demodulation process (step 306) are performed simultaneously. . As shown in FIG. 3, here, as an example, it is assumed that the STTD application determination process for P-CCPCH by the SCH demodulation process takes 10 ms. In step 306, P-CCPCH demodulation corresponding to the case where the STTD scheme is applied is performed.

  After the simultaneous processing in steps 305 and 306, the processing branches depending on the result of the STTD application determination in step 305 (step 307). When the STTD method is applied to the P-CCPCH, the setting corresponding to the STTD method is performed (step 308). When the STTD method is not applied to the P-CCPCH, the STTD method is not applied. The setting is made (step 309).

Finally, P-CCPCH demodulation processing is performed according to the above settings (step 310).
Here, since P-CCPCH demodulation processing for one frame has already been performed in step 306, if it is necessary to perform demodulation of x frames in total, in step 310, (x-1) frames (processing) It is only necessary to perform P-CCPCH demodulation processing of time 10 × (x−1) ms).

Alternatively, when it is only necessary to confirm that the CRC determination is OK, for example, if a CRC is added every 2 frames (20 ms), considering the case where the start frame is shifted, 3 It suffices to perform P-CCPCH demodulation processing of a frame (30 ms).
This completes the cell search process (step 311).

  By performing such a demodulation process, the ST-TD application determination process for the P-CCPCH by the SCH demodulation process can be performed in parallel with a part of the P-CCPCH demodulation process, so that the time required for the demodulation process as a whole is reduced. It can be shortened.

  Also, in general, P-CCPCH demodulation is erroneously performed as non-applied even though the STTD scheme is applied, rather than P-CCPCH demodulation when the STTD scheme is not applied but erroneously applied. In this case, the degradation of the demodulated signal becomes larger. For this reason, in the P-CCPCH demodulation processing in step 306, it is possible to suppress the deterioration of the top frame by setting the default setting so that P-CCPCH demodulation is performed with the setting of STTD scheme application.

  FIG. 4 is a flowchart showing the flow of demodulation processing in the second mode. In FIG. 4, steps 301 to 310 are the same as the processing in the first aspect described above, and thus description thereof is omitted here.

  After performing the P-CCPCH demodulation process in step 310, it is determined whether or not the acquired data is correct (step 412). Here, the determination process is performed by checking the CRC added to the acquired data. However, the determination process is not limited to this, and various known methods can be used.

  If it is determined in step 412 that the data is correct by the CRC check, the cell search process is terminated (step 311). In this case, the same processing as in the first aspect is eventually performed.

  On the other hand, if it is determined in step 412 that the data is not correct by the CRC check, the accuracy of the P-CCPCH demodulation processing performed in the default setting in step 306 is not good (that is, the default for applying the STTD scheme). The setting may not have been appropriate. Therefore, the P-CCPCH demodulation process is extended for the time required for the P-CCPCH demodulation process in step 306, that is, 10 ms (step 413). Thereafter, the cell search process is terminated (step 311).

  By performing such demodulation processing, in the same manner as the first aspect, by performing in parallel the STTD application determination processing of P-CCPCH by SCH demodulation processing and a part of P-CCPCH demodulation processing, If it is later determined that the P-CCPCH demodulation process performed by default setting is not an appropriate process while reducing the demodulation process time, the P-CCPCH demodulation process is performed for the time required for the process. By extending, a more accurate demodulation result can be obtained as a whole.

  FIG. 5 is a flowchart showing the flow of demodulation processing in the third mode. In FIG. 5, steps 301 to 310 and steps 412 and 413 are the same as the processes in the first aspect and the second aspect described above, and thus the description thereof is omitted here.

  After the processing in step 412 or 413, it is further determined whether or not the acquired data is correct (step 512). This determination process can be performed in the same manner as the process in step 412. If it is determined that the acquired data is correct, the cell search process is terminated as it is (step 311).

  On the other hand, if it is determined in step 512 that the acquired data is not correct, the P-CCPCH demodulation processing performed in the previous stage (steps 310 and 413) was set to apply STTD method or not applied to STTD method. (Step 513).

  If P-CCPCH demodulation processing is performed in the previous stage with the STTD scheme applied setting, the STTD scheme is not applied (step 514), and the P-CCPCH demodulation processing is performed in the previous stage with the STTD scheme not applied setting. If so, the STTD method is applied (step 515). Thereafter, P-CCPCH demodulation processing for x frames is performed according to the above settings (step 515).

  In step 512, if the acquired data is not correct, it is determined that the STTD application determination by SCH demodulation in step 305 is incorrect, the setting of STTD scheme application / non-application is switched, and P-CCPCH demodulation is performed again. Processing is to be performed.

  By performing such demodulation processing, whether or not there is an error in the result of the STTD application determination processing by SCH demodulation can be detected by checking the finally obtained data, and an error is detected. In such a case, the accuracy of P-CCPCH demodulation can be improved without increasing the processing time by re-starting the P-CCPCH demodulation process from the beginning with appropriate settings.

  Here, the process of determining whether the STTD scheme is applied to the P-CCPCH by SCH demodulation in the receiving apparatuses of the first embodiment and the second embodiment described above will be specifically described. This determination process is performed in the STTD application determination unit 166 of the receiving apparatus, and corresponds to the STTD application determination process (step 305) by the SCH demodulation process shown in FIGS.

  FIG. 6 is a graph showing a probability distribution of data serving as a reference for STTD application determination processing by SCH demodulation. This reference data is transmitted as a parameter “a” superimposed on the SCH. In this embodiment, if a = 1, the STTD method is applied, and if a = −1, the STTD method is not used. It shall represent the application. FIG. 6 shows a probability distribution when the probability of application / non-application of the STTD method is 50%. Further, in this receiving apparatus, as a result of the averaging process by the in-phase addition being performed in the averaging processing unit 165, the probability distribution of the reference data “a” acquired in the STTD application determining unit 166 is a Gaussian distribution.

  As is clear from the probability distribution diagram shown in FIG. 6, the threshold for minimizing the determination error is x = 0, and it is sufficient to determine whether the STTD method is applied or not using a = 0 as a threshold value. .

  However, in the receiving apparatus of the present invention, P-CCPCH demodulation is applied when the STTD scheme is not applied, but P-CCPCH demodulation is applied, but P-CCPCH is erroneously applied when the STTD scheme is applied. Since the degradation of the demodulated signal is larger in the case of CCPCH demodulation, as shown in FIG. 7, the threshold is offset to the negative side, and the probability that the STTD method is not applied is applied when the STTD method is not applied. It is preferable to lower relative to the probability of error. This increases the probability of erroneous application when the STTD method is not applied, but the degradation amount of the demodulation performance in that case is small, and as a result, the characteristics of P-CCPCH demodulation are improved in the entire receiving apparatus. .

  By the way, as shown in FIG. 7, if the amount of offset of the threshold used as a criterion for application / non-application of the STTD method is set to a fixed value, the effect is constant in a mobile communication environment in which the SCH amplitude is likely to fluctuate. Disappear. That is, if the average amplitude of the SCH is relatively large, the effect of offsetting the threshold is not so much, whereas if the average amplitude of the SCH is relatively small, the effect of offsetting the threshold appears more than necessary. . Therefore, it is preferable that the threshold offset amount be adaptively changed according to the propagation path condition.

  FIG. 8 is a flowchart showing a process flow of the fourth operation mode in which the receiving apparatus shown in FIGS. 1 and 2 performs the demodulation process according to steps 1 to 3 of the cell search of the 3GPP standard. In FIG. 8, Step 301, Step 302, Step 304, and Step 307 to Step 311 are the same as the processing in the first aspect described above, and thus the description thereof is omitted here.

  After performing step 1 of the cell search in step 302, in step 801, as normal step 2, the scrambling code group identification process and the frame head timing acquisition process are performed, and the average SCH amplitude is acquired. I do.

  The average amplitude of SCH is calculated from the average received electric field strength of SCH. In general, the received electric field strength of SCH is also used in the scrambling code group identification process and the frame head timing acquisition process, and can be calculated using the same one.

  In step 801, after performing step 2, in step 304, scrambling code identification processing is performed. At the same time, in step 802, the threshold offset for use in the subsequent STTD method application / non-application determination processing is performed. Determine the value.

  The threshold offset value is, for example, the average amplitude value of the SCH obtained in step 801.

と、あらかじめ決められたオフセット係数κとを用いて、以下の数式により与えられるものとすることができる。

And a predetermined offset coefficient κ can be given by the following formula.

尚、実際のオフセット値は、０．１程度である。

The actual offset value is about 0.1.

  After that, in step 803, STTD scheme application / non-application determination processing is performed based on the SCH demodulation result. Here, it is assumed that the offset value determined in step 802 is added to the determination process.

  By performing such demodulation processing, even in a mobile communication environment in which the SCH amplitude is likely to fluctuate, it is possible to adaptively determine whether the STTD method is applied or not according to a change in propagation path conditions. Errors can be reduced.

  In the above, in step 2 of cell search (step 802), the average amplitude value of SCH is calculated from the average received electric field strength of SCH. However, in addition to this method, for example, it is transmitted from a communication base station. When the SCH power offset amount is known with respect to the CPICH transmission power, the average reception electric field strength information of the CPICH is obtained using the CPICH average reception field strength information obtained at the time of identifying the scramble code in step 3 (step 304). The electric field strength may be calculated, and thereby the average amplitude value of SCH may be obtained.

  Similarly, when the SCH power offset amount is known with respect to the P-CCPCH transmission power transmitted from the communication base station, the average received electric field strength of the P-CCPCH is set simultaneously with the P-CCPCH demodulation processing. It is also possible to obtain the SCH average received electric field strength using this, and obtain the SCH average amplitude value.

  In this way, if the CPICH that is constantly transmitted and the P-CCPCH that is transmitted 9 symbols per slot can be used, the SCH can be compared with the case where the SCH that transmits only 1 symbol per slot is used. The average received electric field strength can be estimated with higher accuracy.

  The receiving apparatus used for W-CDMA wireless communication according to the present invention has been described with reference to specific embodiments. However, the present invention is not limited to these. A person skilled in the art can make various changes and improvements to the configurations and functions of the invention according to the above-described embodiments or other embodiments without departing from the gist of the present invention.

  The receiving apparatus used for W-CDMA wireless communication of the present invention can be used in mobile communication such as a mobile phone, and is particularly useful when the transmitting station side uses an antenna diversity system.

1 is a functional block diagram schematically showing an internal configuration of a demodulation processing mechanism in a first embodiment of a receiving apparatus (mobile station) used for W-CDMA wireless communication according to the present invention. It is a functional block diagram which shows roughly the internal structure of the demodulation processing mechanism about 2nd Embodiment of the receiver (mobile station) used for the radio | wireless communication of the W-CDMA system of this invention. 3 is a flowchart showing a flow of processing in a first operation mode in which demodulation processing is performed according to steps 1 to 3 of 3GPP standard cell search in the receiving apparatus shown in FIGS. 1 and 2. 3 is a flowchart showing a processing flow of a second operation mode in which demodulation processing is performed according to steps 1 to 3 of 3GPP standard cell search in the receiving device shown in FIGS. 1 and 2. 3 is a flowchart showing a flow of processing for a third operation mode in which demodulation processing is performed according to steps 1 to 3 of cell search of 3GPP standard in the receiving apparatus shown in FIGS. 1 and 2. It is a graph which shows the probability distribution of the data used as the reference | standard of the STTD application determination process by SCH demodulation. It is a graph which shows the probability distribution of the data used as the reference | standard of the STTD application determination process by SCH demodulation, and shows the threshold value offset to the minus side. 3 is a flowchart showing a processing flow of a fourth operation mode in which demodulation processing is performed according to steps 1 to 3 of 3GPP standard cell search in the receiving device shown in FIGS. 1 and 2. It is a block diagram which shows roughly the structural example of the demodulator of SCH in the conventional mobile station (wireless communication terminal). In the example shown here, it is assumed that a general demodulation method based on TSTD is used.

Explanation of symbols

110, 120 CPICH receiving unit 111, 121 Despreading unit 112, 122 Propagation path estimating unit 130 First SCH receiving unit 131 Despreading unit 132 Multiplying unit 140 Second SCH receiving unit 141 Despreading unit 142 Multiplying unit 150 P- CCPCH demodulation unit 151-a, 151-b Despreading unit 152-a, 152-b Multiplying unit 161, 162 Complex conjugate operation unit 163 Selection unit 164 Combining unit 165 Averaging processing unit 166 STTD application determining unit 167 Control unit 168 Selection Unit 169 STTD decoding unit 250 P-CCPCH demodulating unit 263 selecting unit 264 combining unit 910,920 pilot channel (CPICH) receiving unit 911, 921 despreading unit 912, 922 propagation path estimating unit 930 SCH receiving unit 931 despreading unit 932 multiplication Unit 941 Selection unit 942 Control unit 9 3 complex conjugate calculation unit

Claims (32)

A plurality of CPICH receivers corresponding to each of a plurality of antennas provided on the transmission side;
A plurality of SCH receivers that demodulate the SCH using propagation path estimation values obtained in each CPICH receiver;
A selection / synthesis unit that selects and combines one or more of the SCHs demodulated by the plurality of SCH reception units at a predetermined timing;
An STTD application determination unit that determines whether the STTD scheme is applied to the CCPCH of the received signal based on the SCH combined in the selection / combination unit;
When the CCPCH is demodulated using the propagation path estimation value obtained in each CPICH receiving unit, and the STTD application determining unit determines that the STTD method is applied to the CCPCH, the STTD demodulating process is further performed on the CCPCH. And a CCPCH demodulator for performing W-CDMA reception.   The selection / combination unit performs combining by always using one SCH among the SCHs demodulated by the plurality of SCH reception units and selectively using another SCH. 2. A W-CDMA receiving apparatus according to 1.   The SCH that is always used in the selection / combination unit is a SCH demodulated for a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. W-CDMA receiver.   4. The W-CDMA reception apparatus according to claim 1, wherein the selection / combination unit selects and combines the SCH for each slot included in the reception frame. 5.   5. The W-CDMA reception according to claim 4, wherein the selection / combination unit selects and combines the SCH depending on whether the slot is an even-numbered slot or an odd-numbered slot in a received frame. apparatus. A plurality of CPICH receivers corresponding to each of a plurality of antennas provided on the transmission side;
A selection / synthesis unit that selects and combines one or more of the propagation path estimation values obtained in each CPICH reception unit at a predetermined timing;
An SCH receiving unit that demodulates the SCH using the propagation path estimation value synthesized in the selection / synthesis unit;
An STTD application determining unit that determines whether the STTD scheme is applied to the CCPCH of the received signal based on the SCH demodulated in the SCH receiving unit;
When the CCPCH is demodulated using the propagation path estimation value obtained in each CPICH receiving unit, and the STTD application determining unit determines that the STTD method is applied to the CCPCH, the STTD demodulating process is further performed on the CCPCH. And a CCPCH demodulator for performing W-CDMA reception.   The selection / combination unit performs synthesis by always using one propagation path estimation value among the propagation path estimation values obtained in each CPICH reception unit and selectively using another propagation path estimation value. The W-CDMA receiver according to claim 6.   The propagation path estimation value that is always used in the selection / combination unit is an estimation value of a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. The receiving apparatus of W-CDMA system as described.   The W-CDMA receiving apparatus according to any one of claims 6 to 8, wherein the selecting / combining unit selects and combines the propagation path estimation values for each slot included in the received frame. .   10. The W-CDMA according to claim 9, wherein the selection / combination unit selects and combines the propagation path estimation values depending on whether the slot is an even-numbered slot or an odd-numbered slot in a received frame. Type receiver. The W-CDMA receiver according to any one of claims 1 to 10,
The CCPCH demodulator starts operating simultaneously with the SCH receiver. The W-CDMA receiver according to claim 11,
Until the determination result is obtained by the STTD application determination unit, the CCPCH demodulation unit performs STTD demodulation processing on the CCPCH. The W-CDMA receiver according to claim 11 or 12,
If the characteristics of the CCPCH demodulated by the CCPCH demodulator does not meet a predetermined standard,
A receiving apparatus characterized in that the CCPCH demodulation unit performs demodulation processing in an extended manner. The W-CDMA receiver according to claim 13,
The CCPCH demodulation unit extends the demodulation process by the same length as the length of the reception signal required for the determination process by the STTD application determination unit. The W-CDMA receiver according to claim 13,
The CCPCH demodulation unit extends the demodulation process by the same amount of time as the time required for the determination process by the STTD application determination unit. The W-CDMA receiver according to any one of claims 13 to 15,
Even when the demodulation process is extended in the CCPCH demodulator, the demodulated CCPCH characteristics do not satisfy a predetermined standard.
When the STTD application determining unit determines that the STTD method is applied to the CCPCH, the CCPCH demodulating unit demodulates the CCPCH without applying the STTD demodulation process,
The receiving apparatus, wherein when the STTD application determining unit determines that the STTD scheme is not applied to the CCPCH, the CCPCH demodulating unit applies the STTD demodulation process to demodulate the CCPCH. The W-CDMA receiver according to any one of claims 11 to 16,
A receiving apparatus, wherein an offset is provided in a determination criterion by the STTD application determining unit. The W-CDMA receiver according to claim 17,
The receiving apparatus according to claim 1, wherein the determination reference offset amount is determined based on a received electric field strength of the SCH. The W-CDMA receiver according to claim 17,
The receiving apparatus according to claim 1, wherein the determination reference offset amount is determined based on a CPICH received electric field strength. The W-CDMA receiver according to claim 17,
The receiving apparatus according to claim 1, wherein the determination reference offset amount is determined based on a reception electric field strength of CCPCH. The W-CDMA receiver according to claim 17,
The receiving apparatus according to claim 1, wherein the offset of the criterion is shifted to the STTD system application side. In a W-CDMA receiving apparatus, a method for determining whether the STTD method is applied to the CCPCH of a received signal,
Calculating each channel estimation value of a plurality of antennas provided on the transmission side using the received CPICH;
Demodulating the SCH in a plurality of systems using the calculated propagation path estimated values;
Selecting and synthesizing one or more of the SCHs demodulated by the plurality of systems at a predetermined timing;
Determining whether the STTD scheme is applied to the CCPCH of the received signal based on the selected and combined SCH.   23. The method according to claim 22, wherein in the selecting and combining step, combining is performed by always using one SCH among the SCHs demodulated by the plurality of systems and selectively using another SCH. the method of.   The SCH that is always used in the selecting and combining step is an SCH demodulated for a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. the method of.   The method according to any one of claims 22 to 24, wherein, in the selecting and combining step, the SCH is selected and combined for each slot included in the received frame.   The method according to claim 25, wherein in the selecting and combining step, the SCH is selected and combined depending on whether the slot is an even-numbered slot or an odd-numbered slot in a received frame. In a W-CDMA receiving apparatus, a method for determining whether the STTD method is applied to the CCPCH of a received signal,
Calculating each channel estimation value of a plurality of antennas provided on the transmission side using the received CPICH;
Selecting and synthesizing one or more of the calculated propagation path estimated values at a predetermined timing; and
Demodulating the SCH using the selected and synthesized propagation path estimates;
Determining whether the STTD scheme is applied to the CCPCH of the received signal based on the demodulated SCH.   In the selecting and combining step, combining is performed by always using one propagation path estimation value and selectively using another propagation path estimation value among the calculated propagation path estimation values. The method of claim 27.   29. The propagation path estimation value that is always used in the selecting and combining step is an estimation value of a propagation path that is always used for transmission regardless of the number of transmission antennas provided on the transmission side. The method described in 1.   30. The method according to any one of claims 27 to 29, wherein the selecting and combining step selects and combines a propagation path estimation value for each slot included in the received frame.   The method according to claim 30, wherein the selecting and combining step selects and combines the propagation path estimation values depending on whether the slot is an even-numbered slot or an odd-numbered slot in a received frame.   32. A program for executing the method according to any one of claims 22 to 31 in a W-CDMA receiver.

Images