JP2003244096A - Wireless reception circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless reception circuit capable of efficiently correcting a phase of user information with high accuracy. <P>SOLUTION: The wireless reception circuit respectively demodulates known pilot information transmitted from different physical communication channels and individual user information sent through any of the physical communication channels, respectively calculates the reception power of respective demodulated pilot information items, and respectively stores a time when the respective pilot information items are demodulated and a time when the user information is demodulated. Then the wireless reception circuit selects one of all the demodulated pilot information items on the basis of the reception power of the respective pilot information items and temporal closeness between the time when the respective pilot information items are demodulated and the time when the user information is demodulated and corrects the phase of the user information by using the selected pilot information. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiving circuit used in a mobile communication system using a spread spectrum technique as a communication system. 2. Description of the Related Art In a communication system using a spread spectrum technique, data (signal) modulated and spread is transmitted from a transmitting side, and data received at a receiving side is despread and demodulated to transmit and receive data. . In a communication system using spread spectrum technology, the frequency spectrum of data is spread over a wide band, so it is excellent in interference resistance and communication confidentiality, and many users can share the same frequency band channel. In recent years, it has been widely used in mobile communication systems such as mobile phones. A communication system using the spread spectrum technique includes, for example, a CDMA (code division multiple access) system. In a mobile communication system, radio communication is performed between a base station and a mobile station by radio waves. At this time,
The radio wave is transmitted at a predetermined transmission power from the transmission side, attenuates before being received by the reception side, and the reception power decreases. Also, due to the effects of fading, a plurality of signals transmitted through a plurality of paths (multipaths) and having different time differences (phase differences) at different transmission distances interfere with each other to strengthen or weaken the signals. Or Therefore, in a mobile communication system using the spread spectrum technique, the transmitting side transmits individual user information (data symbol) different for each user, and a known signal serving as a reference signal when performing phase correction. On the receiving side, performs channel estimation (estimation of phase shift) using the known pilot information, and performs phase correction of individual user information based on the estimation result. Has been done. [0006] The pilot information is transmitted, for example, in a time-division manner on a physical communication channel (DPCH: dedicated physical channel) through which individual user information is transmitted, or via a physical communication channel dedicated to pilot information (CPICH: common pilot channel). Has been sent. In a conventional mobile communication system, phase correction is performed using pilot information transmitted via one or both of the DPCH and the CPICH. For example, when performing phase correction of user information using pilot information of CPICH, as shown in an example of FIG. 3 (a), the user uses predetermined pilot information CP0 of pilot information of CPICH. Information DAT
A1 phase correction is performed. On the other hand, when the phase correction of the user information is performed using the pilot information of the DPCH, the phase correction of DATA1 is performed using the pilot information P0, as shown in an example in FIG. Generally, in the DPCH, power control (closed loop power control) is performed between a base station and a mobile station by monitoring each other's reception status in order to realize an optimum reception environment. Normally, the transmission power of the CPICH is higher than that of the DPCH, but the transmission power of the DPCH may be higher due to the power control described above. In particular, in the case of the DPCH having a small spreading factor, the transmission power is set to be large from the beginning to secure the gain, so that this tendency becomes remarkable. [0009] Specifications of next-generation mobile phones (3G specifications)
In the compressed mode (mode for switching to a different frequency band when the line capacity of the used frequency band becomes tight) required for inter-frequency handover specified in Transmission of individual user information is stopped for a certain period of time (data is thinned out as a result). In this case, the transmission power of the DPCH may be made larger than usual in order to compensate for the energy of the thinned data. When performing phase correction, it is more advantageous that the energy of known pilot information serving as a reference signal is large. Further, since the radio wave condition changes every moment, it is desirable to perform phase correction using pilot information transmitted at a time close to the transmission time of the correction target data. Therefore, if only one of the CPICH and the DPCH is fixedly used, as described above, the efficiency is poor when the magnitude relation of the transmission power is reversed or when the phase correction value update timing is reversed, and the accuracy is low. There is a problem that phase correction cannot be performed well.
On the other hand, if both CPICH and DPCH are always used, there is a problem that the number of processes in the circuit increases, the power consumption in the mobile device increases, and the driving time is shortened. SUMMARY OF THE INVENTION An object of the present invention is to provide a radio receiving circuit which can solve the problems based on the prior art and can efficiently and accurately correct the phase of user information. It is in. [0012] In order to achieve the above object, the present invention provides a method for transmitting known pilot information transmitted through different physical communication channels and one of the known pilot information. Demodulating means for respectively demodulating individual user information transmitted via the demodulator, calculating means for calculating received power of each of the pilot information demodulated by the demodulating means, and each of the pilots by the demodulating means. Storage means for storing the time at which the information was demodulated and the time at which the user information was demodulated, respectively, the reception power of each of the pilot information calculated by the calculation means, and the respective ones stored by the storage means The time when the pilot information was demodulated and the time when the user information was demodulated Selecting means for selecting one of all the pilot information transmitted via the different physical communication channels demodulated by the demodulating means, based on a temporal proximity between Correction means for correcting the phase of the user information by using the obtained pilot information. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a radio receiving circuit according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings. FIG. 1 is a schematic diagram showing the configuration of an embodiment of a radio receiving circuit according to the present invention. The wireless receiving circuit 10 shown in FIG.
Using one of the pilot information (pilot symbols) transmitted through two physical communication channels, DPCH (dedicated physical channel) and CPICH (common pilot channel), the signal is transmitted via the DPCH. This is to correct the phase of individual user information (data symbols). Here, the data (signal) transmitted via the DPCH is, for example, as shown in FIG. 2, an example of known symbol information P which is known in advance on the receiving side. , And individual user information DATA that is different for each user. DPC
In H, the symbol information is inserted in a time division manner between the user information and the user information every predetermined symbol period.
On the other hand, all data transmitted via the CPICH is known symbol information CP. The radio receiving circuit 10 is used in a mobile communication system. As shown in FIG. 1, a DPCH despreading unit 12, a CPICH despreading unit 14, reception power calculation circuits 16 and 18, and a DPCH Channel estimation update timer 20 and CPICH channel estimation update timer 2
2, a DPCH symbol timer 24, a channel estimation value selection signal generation circuit 26, a selector 28, and a channel estimation unit (not shown). First, the DPCH despreading unit 12
The known pilot information and the individual user information transmitted via the CDMA are despread and demodulated respectively. Also,
CPICH despreading section 14 despreads and demodulates known pilot information transmitted via CPICH.
Both the data demodulated by the DPCH despreading unit 12 and the data demodulated by the CPICH despreading unit 14 are supplied to a selector 28 and received power calculation circuits 16 and 18 respectively.
Is input to Note that the user information demodulated by the DPCH despreading unit 12 is input to a channel estimation unit (not shown). Subsequently, the reception power calculation circuits 16, 18
The reception power of each pilot information demodulated by the DPCH despreading unit 12 and the CPICH despreading unit 14 is calculated. All pieces of received power information of the respective pilot information calculated by the received power calculation circuits 16 and 18 are input to the channel estimation value selection signal generation circuit 26. Subsequently, the DPCH channel estimation value update timer 20 and the CPICH channel estimation value update timer 22 store the time when the respective pilot information is demodulated by the DPCH despreading unit 12 and the CPICH despreading unit 14. DPCH channel estimation value update timer 2
0 and the time information stored in the CPICH channel estimation value update timer 22 are both input to the channel estimation value selection signal generation circuit 26. Also, the DPCH symbol timer 24
The individual user information transmitted via the DPCH is D
The time demodulated by the PCH despreading unit 12 is stored. The time information stored in the DPCH symbol timer 24 is also input to the channel estimation value selection signal generation circuit 26. The channel estimation value selection signal generation circuit 26
The difference between the received power of each pilot information and the closeness (time difference) between the time when each pilot information is demodulated and the time when the user information stored by the DPCH symbol timer 24 is demodulated. Based on this, it outputs a selection signal for selecting one of the pilot information transmitted via DPCH or CPICH. This selection signal is input to the selector 28. Finally, the selector 28 selects the DPCH despreading unit 12 and the CPICH despreading unit 1 according to the selection signal supplied from the channel estimation value selection signal generation circuit 26.
4, one of the demodulated symbol information is selectively output as a channel estimation value. This channel estimation value is input to a channel estimation unit (not shown). Next, the operation of the radio receiving circuit 10 will be described. In the illustrated radio receiving circuit 10, the DPCH
The individual user information is sequentially despread and restored by the despreading unit 12, and the time when the user information is demodulated is represented by DP.
It is stored in the CH symbol timer 24. The symbol information inserted between the user information and the user information every predetermined symbol period is despread and restored, and the time when the pilot information is demodulated is stored in the DPCH channel estimation value update timer 20. Is done. Similarly, the CPICH despreading unit 14
The symbol information is despread and restored at every predetermined symbol period, and the time when this pilot information is demodulated is determined by the CPI.
It is stored in the CH channel estimation value update timer 22. In this embodiment, for the sake of simplicity, the symbol period is set to a predetermined symbol period. However, the period in which the symbol information of CPICH is used may not be constant, or may be constant as in this embodiment. In that case, the period is not limited at all. Subsequently, the reception power calculation circuits 16 and 18 use the DPCH despreading unit 12 and the CPICH despreading unit 1
4, the received power of each piece of pilot information demodulated is calculated. Thereafter, the channel estimation value selection signal generation circuit 26 generates a difference between the reception powers of the pilot information of the DPCH and the CPICH and the DPCH and the CPICH.
The DPCH despreading unit 12 or the CPCH despreading unit 12 or CP is used based on both the temporal proximity between the time at which the pilot information of each PICH is demodulated and the time at which the user information is demodulated.
A selection signal for selecting one of the pilot information demodulated by the ICH despreading unit 14 is output. Here, the difference between the received powers of the pilot information of the DPCH and the CPICH, and the DPCH
It is possible to arbitrarily set how to determine both the temporal proximity between the time at which the pilot information of each of the CPICH and CPICH is demodulated and the time at which the user information is demodulated to determine the selection signal. . For example, the reception powers of the pilot information of DPCH and CPICH are 12 dB and 15 dB, respectively.
B, and the time difference between the time when the pilot information of each DPCH and CPICH is demodulated and the time when the user information is demodulated are 10 chips and 100 chips, respectively. In this case, if it is determined only by the magnitude relation of the received power, a selection signal for outputting the CPICH pilot information as a channel estimation value is output. On the other hand, if the condition is set such that the difference between the received powers of 5 dB or less is ignored, the difference between the two received powers is ignored, and the time when the pilot information is demodulated and the time when the user information is demodulated. D with small time difference between
A selection signal for outputting the PCH pilot information as a channel estimation value is output. As described above, the criterion for determining the selection signal can be arbitrarily set, and may be determined as needed. Subsequently, according to the selection signal output from the channel estimation value selection signal generation circuit 26, the selector 28
Thus, one of the symbol information demodulated by the DPCH despreading unit 12 and the CPICH despreading unit 14 is selectively output as a channel estimation value. Then, the channel estimation unit performs phase correction of the user information based on the channel estimation value. For example, in the example shown in FIG. 2, according to the difference in received power, DPICH is used by using symbol information CP0 of CPICH.
The ATA1 phase is corrected. After that, the mode is switched to the compressed mode, and the communication between them is cut off. When communication is resumed, phase correction of the first half of DATA2 is performed using the symbol information P1 of the DPCH in accordance with the difference in received power, but phase correction of the second half of DATA2 is performed according to the closeness of time. Using the symbol information CP1. As described above, in the radio receiving circuit 10 of the present invention, the difference between the received powers of the respective pilot information and the time between the time when the respective pilot information is demodulated and the time when the user information is demodulated. Using the DPCH despreading unit 12 or the CPIC
Since one of the pilot information demodulated by the H despreading unit 14 is used as the channel estimation value, the received power is always large, and the phase correction of the user information is accurately performed using the pilot information that is close in time. be able to. In the above embodiment, the DPCH and the CPICH have been described as examples of the physical communication channels. However, the present invention is not limited to this, and the number of physical communication channels and the data format thereof are not limited at all. It is not done. The wireless receiving circuit of the present invention is basically as described above. As described above, the wireless receiving circuit of the present invention has been described in detail. However, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. is there. As described above in detail, the radio receiving circuit according to the present invention is capable of demodulating the received power of pilot information transmitted through each physical communication channel and demodulating each pilot information. One of all demodulated pilot information is selected based on the temporal proximity between the demodulated time and the time at which the user information is demodulated, and the user information is selected using the selected pilot information. Is corrected in phase. As a result, according to the wireless reception circuit of the present invention, it is possible to accurately correct the phase of user information using pilot information that always has a large received power and is close in time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of one embodiment of a wireless receiving circuit of the present invention. FIG. 2 is a conceptual diagram of one embodiment showing an operation of the wireless reception circuit of the present invention. FIGS. 3A and 3B are conceptual diagrams illustrating an example of an operation of a conventional wireless receiving circuit. [Description of Code] 10 Radio receiving circuit 12 DPCH despreading unit 14 CPICH despreading unit 16, 18 Received power calculation circuit 20 DPCH channel estimation value update timer 22 CPICH channel estimation value update timer 24 DPCH symbol timer 26 Channel estimation value selection signal Generation circuit 28 Selector

Claims (1)

Claims 1. Known pilot information transmitted via different physical communication channels and individual user information transmitted via one of said physical communication channels are respectively Demodulating means for demodulating; calculating means for calculating received power of each of the pilot information demodulated by the demodulating means; and a time at which the pilot information is demodulated by the demodulating means and the user information are demodulated. Storage means for storing the received times, the received power of each of the pilot information calculated by the calculation means, and the time and the user information at which each of the pilot information stored by the storage means was demodulated. Based on the temporal proximity to the demodulated time, the demodulation means Therefore, selecting means for selecting one of all the pilot information transmitted via the different physical communication channels demodulated, and performing phase correction of the user information using the selected pilot information. A wireless receiving circuit, comprising: a correction unit.