JP2002353859A - Frequency control method for w-cdma communication system and mobile station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an initial cell search method to realize a circuit of a 3-stage cell search system and a circuit for an initial cell search. SOLUTION: The cell search circuit is provided with a matched filter MF and a sliding correlator section SC receiving a reception signal Sin, the matched filter MF conducts a correlation arithmetic operation between the received signal Sin and a 1st synchronous code PSC, a memory MEM1 stores its output Spsc and the output is processed by a timing detection section TDP. The sliding correlator section SC comprises sliding correlators SC1-SCz, and after the outputs A [1]-A [z] are stored by a memory MEM2, these are processed by a timing group specification section TG1. A final output or a midway output of the matched filter MF is outputted to a phase error detection section FC and a phase error is outputted to a frequency control section AFC.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct spread code division multiple access (DS-CDMA) communication system, and more particularly to a frequency control for reducing the influence of a frequency deviation between a mobile station and a base station in an initial cell search process. The present invention relates to a method and its receiving device.

[0002]

2. Description of the Related Art In recent years, wide-band direct spreading code division multiple access (W-CDM) has attracted attention in the field of mobile communications.
A) In the communication method, the initial cell search requires a lot of time since it performs arithmetic processing for initial synchronization and base station identification in the initial cell search. Therefore, a three-stage cell search scheme has been proposed in which scramble codes for specifying a base station are divided into groups, a second synchronization code (search code) for specifying the group is set, and the initial cell search is speeded up (“W -Analysis of Cell Search Characteristics in CDMA Cellular System ", IEICE Transactions, Vol.
B, No. 9, pp1245-1257).

[0003] In the initial cell search, since the frequency synchronization between the base station and the mobile station is not performed, there is a possibility that the frequency deviation between the two is relatively large. In this regard, Y. Wang and T.W. Ottoson's dissertation "CELL SEARCHALGOLITHMAN"
D OPTIMIZATION IN W-CDM
A ", IEEE Vehicle Technology
gy Conference 2000 Spring
g, Tokyo). When the frequency deviation is large, the accuracy of the correlation detection in each stage of the initial cell search decreases, and the erroneous detection rate of the cell search increases.
To solve this problem, the same paper proposes a method using partial correlation within one symbol only in the initial cell search. However, in this method, the original spreading gain of the system cannot be sufficiently utilized, and the S / N ratio cannot be increased.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and a frequency control method capable of preventing erroneous detection due to a frequency deviation in a three-stage cell search system. And a receiving device.

[0005]

According to the present invention, a first synchronization code (search code) common to all base stations and a scrambling code specifying a base station are set, and these scrambling codes are set to a plurality of scrambling codes. A group is set, a combination of a second synchronization code (search code) for specifying each scramble code group is set, and a first synchronization channel (search channel) and a second synchronization channel composed of the first synchronization code are set from the base station. A second synchronization channel (search channel) composed of a synchronization code is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, and performs a first reception based on the correlation operation result. A first step of detecting timing (slot synchronization) and generating a despread signal of the received signal; Second by the first reception timing
Performing a correlation operation using the synchronization code, detecting a second reception timing (frame synchronization) based on the correlation operation result, and specifying a scramble code group, and a second step for specifying the scramble code group A correlation operation using a scramble code is performed, and an initial cell search is performed by a third step of specifying one scramble code, whereby a mobile station specifies a base station from which a signal is to be received. W-CD for communication between mobile station and base station
In the frequency control method for a mobile station in the MA communication system, after completion of the first step of cell search, a phase error between a plurality of slots as a result of a correlation operation using a first synchronization code is detected, and a frequency deviation corresponding to the phase error is detected. The local oscillation frequency of the mobile station is adjusted so as to eliminate it. This enables early frequency adjustment.

According to the present invention, a first synchronization code (search code) common to all base stations and a scramble code for specifying a base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying a code group is set, and the base station configures a first synchronization channel (search channel) composed of the first synchronization code and a second synchronization code. A second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, cyclically integrates the correlation operation result, and based on the cyclic integration result. First reception timing (slot synchronization)
And a first step of generating a despread signal of the received signal, and performing a correlation operation on the received signal at the first reception timing using a second synchronization code, based on the result of the correlation operation. A second step of detecting a second reception timing (frame synchronization) and specifying a scramble code group, and performing a correlation operation using a scramble code included in the specified scramble code group to specify one scramble code The third step performs an initial cell search, whereby the mobile station specifies a base station to receive a signal, and then performs mobile communication in the W-CDMA communication system in which communication between the mobile station and the base station is performed using a plurality of channels. In the frequency control method of the station, before detecting the first reception timing in the first step of the cell search, The peak of the signal power of the correlation operation result is detected, the phase error of the correlation output is detected at a plurality of peak positions at the timing of the peak, and the local oscillation of the mobile station is canceled so as to eliminate the frequency deviation corresponding to the phase error. Adjust the frequency. This allows the frequency adjustment to be performed earlier.

According to the present invention, a first synchronization code (search code) common to all base stations and a scramble code for specifying the base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code is set. A combination of a second synchronization code (search code) for specifying a code group is set, and the base station configures a first synchronization channel (search channel) composed of the first synchronization code and a second synchronization code. A second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, cyclically integrates the correlation operation result, and based on the cyclic integration result. First reception timing (slot synchronization)
And a first step of generating a despread signal of the received signal, and performing a correlation operation on the received signal at the first reception timing using a second synchronization code, based on the result of the correlation operation. A second step of detecting a second reception timing (frame synchronization) and specifying a scramble code group, and performing a correlation operation using a scramble code included in the specified scramble code group to specify one scramble code The third step performs an initial cell search, whereby the mobile station specifies a base station to receive a signal, and then performs mobile communication in the W-CDMA communication system in which communication between the mobile station and the base station is performed using a plurality of channels. In the frequency control method of the station, the correlation calculation in the first step of the cell search is performed by serially connecting a plurality of layers. It is performed hierarchically by a matched filter, and detects a signal power peak of a correlation operation result (hereinafter, referred to as “partial correlation”) before the last layer of the matched filter before detecting the first reception timing in the first step; At the timing of this peak, the phase error of the partial correlation at a plurality of peak positions is detected, and the local oscillation frequency of the mobile station is adjusted so as to eliminate the frequency deviation corresponding to the phase error. Thereby, the timing of frequency adjustment can be further advanced.

According to the present invention, a first synchronization code (search code) common to all base stations and a scramble code specifying a base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying a code group is set, and the base station configures a first synchronization channel (search channel) composed of the first synchronization code and a second synchronization code. A second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, cyclically integrates the correlation operation result, and based on the cyclic integration result. First reception timing (slot synchronization)
And a first step of generating a despread signal of the received signal, and performing a correlation operation on the received signal at the first reception timing using a second synchronization code, based on the result of the correlation operation. A second step of detecting a second reception timing (frame synchronization) and specifying a scramble code group, and performing a correlation operation using a scramble code included in the specified scramble code group to specify one scramble code The third step performs an initial cell search, whereby the mobile station specifies a base station to receive a signal, and then performs mobile communication in the W-CDMA communication system in which communication between the mobile station and the base station is performed using a plurality of channels. In the frequency control method of the station, the correlation calculation in the first step of the cell search is performed by serially connecting a plurality of layers. It is executed hierarchically by a matched filter, and before the first reception timing is detected in the first step, the peak of the signal power of the correlation operation result (hereinafter, referred to as “partial correlation”) in the last layer or before the last layer of the matched filter is determined. Detect and detect the phase error of the correlation output or the phase error of the partial correlation at multiple peak positions at the timing of this peak, and adjust the local oscillation frequency of the mobile station so as to eliminate the frequency deviation corresponding to this phase error I do. Thereby, the frequency detection accuracy and the frequency adjustment timing can be optimized according to the operation status of the mobile station.

The phase error is calculated by, for example, differential detection.

According to the present invention, a first synchronization code (search code) common to all base stations and a scramble code specifying a base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying a code group is set, and the base station configures a first synchronization channel (search channel) composed of the first synchronization code and a second synchronization code. The second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, and determines a first reception timing (slot synchronization) based on the correlation operation result. A first step of detecting and generating a despread signal of the received signal; A second step of performing a correlation operation using a second synchronization code in the imaging, detecting a second reception timing (frame synchronization) based on the result of the correlation operation, and specifying a scramble code group; Performing a correlation operation using the scrambling codes included in the group, and performing a third step of identifying one scrambling code to perform an initial cell search, thereby identifying a base station from which the mobile station should receive a signal, Thereafter, in a mobile station in the W-CDMA communication system in which communication between the mobile station and the base station is performed using a plurality of channels, a matched filter for executing a correlation operation in a first step of cell search, and a correlation to which an output of the matched filter is input. A power calculator, an adder to which an output of the correlation power calculator is input, Is output to a memory that holds the output of the adder in the slot cycle, and the output of the memory is fed back to the adder, thereby accumulating the correlation power by the adder. A timing detection unit for detecting a reception timing, and a first reception timing detected by the timing detection unit, for capturing a plurality of outputs of the matched filter and detecting a phase error of a correlation calculation output over a plurality of slots. An error detection unit; and a frequency control unit that controls a local oscillation frequency of the mobile station so as to eliminate a frequency deviation detected by the phase error detection unit and corresponding to the phase error.

According to the present invention, a first synchronization code (search code) common to all base stations and a scrambling code for specifying the base station are set, and these scrambling codes are divided into a plurality of scrambling code groups, and each scrambling code is set. A combination of a second synchronization code (search code) for specifying a code group is set, and the base station configures a first synchronization channel (search channel) composed of the first synchronization code and a second synchronization code. The second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, and determines a first reception timing (slot synchronization) based on the correlation operation result. A first step of detecting and generating a despread signal of the received signal; A second step of performing a correlation operation using a second synchronization code in the imaging, detecting a second reception timing (frame synchronization) based on the result of the correlation operation, and specifying a scramble code group; Performing a correlation operation using the scrambling codes included in the group, and performing a third step of identifying one scrambling code to perform an initial cell search, thereby identifying a base station from which the mobile station should receive a signal, Thereafter, in the mobile station in the W-CDMA communication system in which communication between the mobile station and the base station is performed by a plurality of channels, a matched filter for executing a correlation operation in the first step of cell search, and an output of the matched filter are input. Correlation power calculator for calculating correlation power, and output of the correlation power calculator An adder input, is input to the memory for holding the output of the adder at the slot cycle, the output of the memory is fed back to the adder,
Accordingly, a memory for accumulating the correlation power by the adder, a timing detection unit for detecting a first reception timing based on an output of the memory, and a correlation power for receiving the output of the matched filter and calculating the correlation power A calculating section, a peak detecting section for detecting a peak position of the correlation power calculated by the correlation power calculating section, and a plurality of outputs of the matched filter at a timing of the peak position detected by the peak detecting section; A frequency control unit including a phase error detection unit for detecting a phase error of a correlation calculation output over a slot, and a frequency deviation corresponding to a phase error detected by the phase error detection unit of the frequency control unit. And a frequency controller for controlling the local oscillation frequency of the mobile station.

According to the present invention, a first synchronization code (search code) common to all base stations and a scramble code for specifying the base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code is set. A combination of a second synchronization code (search code) for specifying a code group is set, and the base station configures a first synchronization channel (search channel) composed of the first synchronization code and a second synchronization code. The second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, and determines a first reception timing (slot synchronization) based on the correlation operation result. A first step of detecting and generating a despread signal of the received signal; A second step of performing a correlation operation using a second synchronization code in the imaging, detecting a second reception timing (frame synchronization) based on the result of the correlation operation, and specifying a scramble code group; Performing a correlation operation using the scrambling codes included in the group, and performing a third step of identifying one scrambling code to perform an initial cell search, thereby identifying a base station from which the mobile station should receive a signal, After that, in a mobile station in the W-CDMA communication system in which communication between the mobile station and the base station is performed by a plurality of channels, a multi-layer serial matched filter for executing a correlation operation of the first step, and a final layer of these matched filters Correlation wattmeter that receives matched filter output and calculates its correlation power , An adder to which the output of the correlation power calculator is input, and a memory that holds the output of the adder in a slot cycle, and the output of the memory is fed back to the adder, whereby the adder A memory for accumulating the correlation power according to the above, a timing detection unit for detecting a first reception timing based on an output of the memory, and an output of a matched filter before the last layer (hereinafter, referred to as “partial correlation”); A correlation power calculator for calculating the correlation power, a peak detector for detecting a peak position of the correlation power calculated by the correlation power calculator, and a plurality of parts at the timing of the peak position detected by the peak detector. A frequency control unit including a phase error detection unit for capturing a correlation and detecting a phase error between partial correlation outputs at a plurality of peak positions; And a frequency control unit for controlling the local oscillator frequency of the mobile station so as to eliminate the frequency deviation corresponding to the phase error detected by the difference detection unit.

According to the present invention, a first synchronization code (search code) common to all base stations and a scramble code for specifying the base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code is set. A combination of a second synchronization code (search code) for specifying a code group is set, and a combination of a first synchronization channel (search channel) including the first synchronization code and a second synchronization code is provided from the base station. The second synchronization channel (search channel) is transmitted, and the mobile station performs a correlation operation on the received signal using the first synchronization code, and determines a first reception timing (slot synchronization) based on the correlation operation result. A first step of detecting and generating a despread signal of the received signal; A second step of performing a correlation operation using a second synchronization code in the imaging, detecting a second reception timing (frame synchronization) based on the result of the correlation operation, and specifying a scramble code group; Performing a correlation operation using the scrambling codes included in the group, and performing a third step of identifying one scrambling code to perform an initial cell search, thereby identifying a base station from which the mobile station should receive a signal, Thereafter, in a mobile station in the W-CDMA communication system in which communication between the mobile station and the base station is performed by a plurality of channels, a multi-layer serial matched filter for executing a correlation operation of a first step, and a final layer of these matched filters Matched filter output and matched filter output before the last layer And a multiplexer for selectively outputting these outputs, an output of the matched filter of the last layer is input, a correlation power calculator for calculating the correlation power, and an output of the correlation power calculator are input. An adder, an output of the adder is output to a memory that holds the output at the slot period, and an output of the memory is fed back to the adder, whereby the memory that accumulates the correlation power by the adder; and an output of the memory. A timing detection unit that detects a first reception timing based on the first reception timing;
A multiplexer to which the output of the matched filter of the last layer and the output of the matched filter before the last layer (hereinafter referred to as "partial correlation") are selectively output, and a correlation power of the output of the multiplexer. , A peak detector for detecting the peak position of the correlation power calculated by the correlation power calculator, and a plurality of outputs of the multiplexer at the timing of the peak position detected by the peak detector. And a phase control unit including a phase error detection unit for detecting a phase error of the correlation output at a plurality of peak positions, and a frequency deviation corresponding to the phase error detected by the phase error detection unit of the frequency control unit. And a frequency control unit for controlling the local oscillation frequency of the mobile station so as to eliminate the problem.

In the mobile station according to the present invention, the phase error detector calculates the phase error by, for example, differential detection.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of a frequency control method and a receiving apparatus for a W-CDMA communication system according to the present invention will be described with reference to the drawings.

FIG. 15 shows a general transmission frame configuration of a three-stage cell search system.

In the three-stage cell search system, a common pilot channel CPICH, a first synchronization (search) channel P-SCH, and a second synchronization (search) channel S-SC
H is provided. Common pilot channel CPICH
Uses a pilot pattern, and a first synchronization (search) channel P-SCH uses a first synchronization code PSC common to all base stations.

The base station receives the scramble code GC [i,
j] (i = 1 to p, j = 1 to q), and these scramble codes GC [i, j] are classified into a plurality of scramble code groups SCMG [i] (i = 1 to p).

In the second synchronization channel S-SCH, the second
Synchronization code (search code) SSC [i] (i = 1 to
z) is used, and one scrambling code group SCMG [i] is specified by the combination of the second synchronization codes.

In FIG. 15, the length of one frame is n
[Slot / 1 frame] × N [symbol / 1 slot] × M [chip / 1 symbol], and the correlation operation using the first synchronization code PSC and the second synchronization code SSC [i] is performed for n (slots) in one frame. (Equivalent to the number).

The modulation method of the transmission signal is QPSK (Quad
ratture Phase Shift Keyin
g), and the transmission signal is composed of an in-phase component (I component) and a quadrature component (Q component). [First Embodiment] FIG. 1 is a block diagram showing a mobile station according to a first embodiment of the present invention.

The mobile station includes an antenna 200 and a transmission / reception switch (duplexer) 21 connected to the antenna 200.
0, the transmission / reception switch (duplexer) 210
Are connected to the transmission unit 220 and the reception unit 230. The transmission / reception switch (duplexer) 210 separates the current of the transmission unit 220 and the current of the reception unit 230 to prevent interference.

The transmitting section 220 has a spread modulator 2201 for spreading a digital signal to be transmitted, and a spread modulator 22
The digital / analog converters 2202 and 2203 convert the in-phase component (I component) and the quadrature component (Q component) of the digital output 01 into analog signals. Outputs of the digital / analog converters 2202 and 2203 are subjected to noise removal by low-pass filters 2204 and 2205, respectively.

The outputs of the low-pass filters 2204 and 2205 are input to a quadrature modulator 2206, and the in-phase component (I component) and the quadrature component (Q component) of the signal to be transmitted are converted into one QP.
SK (Quadrature phase shift)
keying) into a modulated signal.

A transmission frequency synthesizer 2207 is connected to the quadrature modulator 2206, and a transmission frequency for QPSK modulation is set.

After the output of the quadrature modulator 2206 is amplified by the variable gain amplifier 2208, the bandpass filter 2209 removes signals other than the predetermined frequency.
The output of the bandpass filter 2209 is input to the mixer 2210 together with the output of the transmission frequency synthesizer 2207, and is modulated. After that, the bandpass filter 221
1, extraction of a predetermined frequency component, variable gain amplifier 22
The signal is input to a transmission / reception switch (duplexer) 210 after being amplified by the power amplifier 12 and the power amplifier 2213.

The receiving section 230 includes a low-noise amplifier 2301 connected to a transmission / reception switch (duplexer) 210, and a band-pass filter 2302 for removing a signal other than a predetermined frequency from the output of the low-noise amplifier 2301.

The output of the band pass filter 2302 is supplied to the mixer 23 to which the reception frequency synthesizer 2304 is connected.
03 and converted to an intermediate frequency signal. The output of the mixer 2303 is subjected to extraction of a predetermined frequency component by a band-pass filter 2305, amplification by a variable gain amplifier 2306, and then quadrature detection by a quadrature detection unit 2307. A reception frequency synthesizer 2304 is connected to the quadrature detector 2307.

A quadrature detector 2307 extracts an in-phase component (I component) and a quadrature component (Q component) of the received signal, and after removing noise by low-pass filters 2308 and 2309, respectively, analog-to-digital converters 2310 and 2311.
Are converted into digital signals.

Analog-to-digital converters 2310, 23
The output of 11 is input to the despreading demodulation unit 2312 and despread.

Further, despreading demodulation section 2312 obtains a frequency deviation between the received signal and the local oscillation frequency of the mobile station, so that phase error PE of the received signal at different reception timings is obtained.
Is calculated and input to the frequency control unit 240. Frequency control section 240 outputs a control signal to temperature-compensated crystal oscillator 250 to adjust the oscillation frequency. The system clock generator 260 is connected to the temperature-compensated crystal oscillator 250, and generates a system clock by dividing the oscillation frequency of the temperature-compensated crystal oscillator 250. The transmission frequency synthesizer 2207 and the reception frequency synthesizer 2304 are connected to the temperature compensated crystal oscillator 250 and generate a signal based on the oscillation frequency of the temperature compensated crystal oscillator 250. Further, the output of the temperature-compensated crystal oscillator 250 is input to the system clock generator 260, and the system clock C of the mobile station is output.
Used to generate LK0.

Normally, the despread demodulator 2312 performs cell search,
It is composed of blocks for path search, synchronous detection, rake combining, channel decoder, RF control and the like. FIG. 2 is a block diagram of the cell search block therein, and the cell search block, FC block (described later) and AFC of the present invention.
It shows the connection relationship with the block.

The cell search block contains the received signal Si
A matched filter MF to which n is input and a sliding correlator SC are provided. Here, the received signal Sin is complex data including an in-phase component (I component) SinI and a quadrature component (Q component) SinQ.

The matched filter MF performs a correlation operation between the received signal Sin and the first synchronization code PSC, and outputs the signal Sin.
The psc is input to the correlation power calculator PW, outputs the signal power value (absolute value) of the correlation operation result, and is stored in the memory MEM1 and then processed by the timing detector TDP. The memory MEM1 has a capacity for one slot, and accumulatively adds the signal power value (absolute value) of the correlation operation result in slot units together with the adder ADD at the preceding stage. As a result, cyclic integration is performed. The output Spsc is complex data composed of an I component SpscI and a Q component SpscQ.

The sliding correlator section SC comprises a plurality of sliding correlators SC1 to SCz (see FIG. 17). The output A [i] (i = 1 to z) is stored in the memory MEM2, and then the timing group is specified. Processed by the section TGI.

The memory MEM1 sets the output of the adder ADD to 1
After holding for the number of slots and holding the correlation power for one slot period in the initial state, it returns to the adder ADD. afterwards,
The adder ADD sequentially adds the correlation power of one slot period to the addition result. Thus, the adder ADD cumulatively adds the correlation power in one slot period. The cumulative addition period is 1
It is a slot (two correlation powers of one slot cycle) or a plurality of slot periods.

The correlation power is subjected to threshold processing by the judgment unit JP1 of the timing detection unit TDP, and a peak is detected.
The first reception timing Tp1 is detected. This first reception timing Tp1 gives the starting point of one slot in FIG.
Slot synchronization will be detected.

The first reception timing Tp1 is input to the sliding correlator SC, and the reception timings of the sliding correlators SC1 to SCz are set. Each of the sliding correlators SC1 to SCz is the second
Synchronization codes SSC [1] to SSC [z] and received signal Si
The correlation operation with n is performed over one frame, and the outputs A [1] to A [z] are output from the matrix AM [i, j] (i = 1
To z; j = 1 to n) are stored in the memory MEM2.
Note that the matrix AM [i, j] is an I component AMI [i, j].
j] and Q component AMQ [i, j].

The timing detector TDP generates a clock CLK1 corresponding to the first reception timing TP1, and inputs this clock CLK1 to the phase error detector FC connected to the output of the matched filter MF. The phase error detection unit FC detects a phase error for calculating a frequency deviation between the frequency of the received signal Sin and the local oscillation frequency of the mobile station, and inputs the phase error to the frequency control unit 240 in FIG. 1 to adjust the local oscillation frequency. I do.

The timing group specifying unit TGI converts each element of the matrix AM [i, j] (i = 1 to z; j = 1 to n) into each scramble code group SCMG.
Default combination pattern PG representing [1] to SCMG [p]
C [i, j, k] (i = 1 to z; j = 1 to n, k = 1 to n) are subjected to in-phase addition by the in-phase addition unit CAP, and based on the in-phase addition result, the correlation power average unit PWA performs the in-phase addition. The average value of the signal power (absolute value) is calculated. By performing a threshold process on the average value of the signal power (absolute value), the determination unit JP
2 is one scramble code group SCMG [g]
Is specified, and the second reception timing Tp2 is specified. The second reception timing gives the start point of the frame, and the frame synchronization is detected.

The timing group specifying unit TGI
Then, the in-phase addition processing of the above-mentioned in-phase addition unit CAP is omitted, and the matrix AM [i, j] (i = 1 to z; j = 1 to
n), the signal power (absolute value) is obtained from each element, and a predetermined combination pattern GC [i, j, k] (i = 1 to p;
It is also possible to perform accumulation processing on j = 1 to z and k = 1 to n) and perform threshold processing on the result.

Next scramble code group SC
The scramble code GC [i, included in MG [i]
j] (i = 1 to p, j = 1 to q), a correlation operation between the received signal Sin, the scramble code and the channelization code of the common pilot channel is performed by the sliding correlator unit SCA. This correlation operation result (Sth [1], Sth [2],..., Sth
[K]), the in-phase component (I component) and the quadrature component (Q
Memory circuit (MEM31, MEM32, ..., MEM3) over one symbol or a plurality of symbols for each component).
9) and cumulative addition by a pre-stage addition circuit of each memory circuit,
Each memory circuit (MEM31, MEM32, ..., ME
M39) calculates the average value of the signal power (absolute value) by a circuit connected to the subsequent stage, and calculates the average value of the signal power (absolute value).
Of the scramble codes GC [i, 1] to GC [i, q]
Identify one.

FIG. 3 is a block diagram showing the phase error detector FC together with the matched filter MF.

The phase error detector FC is a two-stage sample-and-hold 30 to which the matched filter output Spsc is input.
0, 310, and these sample and hold circuits 30
0 and 310 are clocks CLK of the timing detection unit TDP.
The output Spsc is held in synchronization with 1. The outputs of the sample and hold circuits 300 and 310 are input to the inter-slot phase error detection section 320. The clock CLK1 gives the peak position of the correlation output for each slot, and one output Sps
c is the slot-timing sample-and-hold circuit 300
, And transferred to the sample and hold circuit 310 at the next slot timing, and hold the correlation output Spsc at the new slot timing. Accordingly, the sample hold circuit 310 outputs the correlation output Spsc one slot after the sample hold circuit 300 to the inter-slot phase error detection unit 320.

Thus, the inter-slot phase error detector 3
The correlation output at the peak position of two consecutive slots is input to 20 in parallel.

Assuming that the in-phase component of the correlation output Spsc is Di, the quadrature component is Dq, the amplitude thereof is B, the deviation between the carrier frequency and the local oscillation frequency of the mobile station is Δf, the time t, and the base of the natural logarithm is e. The relationship is represented by equation (1).

[0047]

(Equation 1) After the slot synchronization, the inter-slot phase error detecting section 320
The calculations of equations (2) and (3) are performed on the correlation outputs of two consecutive slots to perform delay detection. Equation (2),
Tslot in (3) is a slot cycle.

[0048]

(Equation 2) By extracting only the imaginary part of Expression (3), Expression (4) is obtained. If this is used as a reference signal for the frequency control unit 240 (FIG. 1), the frequency deviation can be eliminated.

[0049]

(Equation 3) The inter-slot phase error detection section 320 inputs the reference signal of Equation (4) to the frequency control section 240 (FIG. 1), and the frequency control section 240 uses the temperature compensation crystal oscillator 250 (FIG. 1) based on the inter-slot phase error. A control signal is generated, and the local oscillation frequency of the mobile station is adjusted so as to eliminate the frequency deviation.
This can prevent erroneous cell detection due to frequency deviation.

FIG. 4 is a flowchart showing the processing of the first embodiment.

In the initial cell search, as a first step, slot synchronization is performed by detecting the first reception timing TP1 (step S401), and based on the slot synchronization result, the phase error detector FC performs P-SCH.
The phase error between the slots of the channel is detected, and the frequency control is executed (step S404).

The second stage of the initial cell search (step S4)
02), the frame synchronization and the identification of the scramble code group are executed, and the third step (step S40) is performed.
In 3), a scramble code is specified.

After specifying the scramble code, frequency control based on the common pilot channel CPICH is executed (step S405), and thereafter, transmission / reception processing with a better local oscillation frequency is executed (step S40).
6). In the frequency control method based on the common pilot channel CPICH, a phase error of a received signal between symbols or slots between CPICH channels is obtained, and the result is output to the frequency control unit 240 in FIG. 1 to perform frequency control. . Note that the common pilot channel CP
Instead of ICH, other common control channels may be based.

Here, conventional initial cell search processing and frequency control will be described with reference to FIG. In the initial cell search, a first step similar to the first embodiment (step S18)
01), the second step (step S1802), and the third step (step S1803) were performed. After the initial cell search was completed, frequency control based on the common pilot channel CPICH was performed, and transmission / reception processing was performed. That is, conventionally, the frequency cannot be controlled unless the initial cell search is completed.

On the other hand, in the first embodiment, the frequency control can be started at the completion of the first stage of the initial cell search, and by performing this in parallel with the second stage, the cell erroneous detection rate of the initial cell search can be reduced. In addition to the reduction, the frequency can be adjusted immediately upon completion of the initial cell search. This can be called real-time frequency adaptive control.

FIG. 16 is a block diagram showing the matched filter MF. The matched filter MF is “Fast Correlation of Hierarchical Correlation Sequence”
nof hierarchical correlat
ion sequence), and the product-sum operation is executed hierarchically to obtain the desired product-sum operation result. The matched filter MF of FIG. 16 includes a first-layer matched filter MF1 and a second-layer MF2 connected in series. However, it is also possible to connect more matched filters hierarchically in series.

The matched filter MF1 includes m multiplication circuits M11 to M1m and delay circuits D11 to D1, which sequentially delay the reception signal Sin and input to the multiplication circuits M12 to M1m.
m-1 and an adder ADD1 for summing the outputs of the multipliers M11 to M1m.

On the other hand, the matched filter MF2 includes m multiplying circuits M21 to M2m, delay circuits D21 to D2, m-1 for sequentially delaying the output of the matched filter MF1 and inputting them to the multiplying circuits M22 to M2m. M21-M2m
And an adder circuit ADD2 for summing the outputs of.

If the received signal Sin is expressed as Sin (i) as a discrete time-series signal, the output Spsc [i] of the matched filter MF is expressed by equation (5). Here, the first synchronization code PSC is a hierarchical correlation sequence, and includes a sequence P [j] (j = 0 to m−1) and a sequence C
[J] (j = 0 to m−1). Although the sequence P [j] and the sequence C [j] have been described as having the same period, they may have different periods.

[0060]

(Equation 4) In the present embodiment, a hierarchical configuration has been described as an example, but a matched filter having any other configuration may be used.

FIG. 17 shows a sliding correlator section SC.
And a plurality of sliding correlators SC1 to SCz are connected in parallel to the received signal Sin. Each sliding correlator SC1
In SCz, the second synchronization (search) code SSC
[1], SSC [2],. . . , SSC [z] and the received signal Sin.

FIG. 18 shows one sliding correlator SC1 as a representative. Sliding correlator SC
1 performs a correlation operation on each of the in-phase component SinI and the quadrature component SinQ of the received signal.

The sliding correlator SC1 has a multiplication circuit MI1 and a multiplication circuit MI2 for the I component SinI of the received signal.
nI and multiplications of the respective I components SSCI [1] to SSCI [z] of the second synchronization codes SSC [1] to SSC [z] are sequentially performed, and the multiplication circuit MI2 performs a time-series reception signal S
The multiplication of inI and the respective Q components SSCQ [1] to SSCQ [z] of the second synchronization codes SSC [1] to SSC [z] is sequentially performed.

Further, the sliding correlator SC1
Is a multiplier MQ1 for the Q component SinQ of the received signal.
And a multiplication circuit MQ2. The multiplication circuit MQ1 includes a time-series reception signal SinQ and second synchronization codes SSC [1] to SSC.
Q component SSCQ [1] to SSCQ of each of [z]
The multiplication circuit MQ2 sequentially executes the multiplication with [z], and the multiplication circuit MQ2 outputs the time-series reception signal SinQ and the second synchronization codes SSC [1] to SSC [
Each I component SSCI [1] to SSC of SC [z]
The multiplication with I [z] is sequentially performed. The output of the multiplication circuit MI1 and the output of the multiplication circuit MQ1 are added by the addition circuit ADDI, and the output is input to the integration / dump circuit INDI to calculate the correlation operation result AI [1]. The outputs of the multiplication circuits MQ2 and MI2 are subtracted by a subtraction circuit ADDQ, and the output is input to an integration / dump circuit INDQ to calculate a correlation operation result AQ [1].

The second synchronization code is a spread code generation circuit SC
G is generated.

[Second Embodiment]

FIG. 5 shows the cell search and operation in the second embodiment.
FIG. 3 is a block diagram showing a block and a connection relationship among a cell search block, an FC block, and an AFC block according to the present invention. The overall configuration of the mobile station (FIG. 1) is the same as that of the first embodiment, and includes a cell search block, an FC block, and an AFC.
Only the connection relationship with the blocks differs from the first embodiment.

In FIG. 5, only the connection between the cell search block and the phase error detector FC differs from the first embodiment, and the other parts are the same. Therefore, parts other than the phase error detection unit FC are denoted by the same reference numerals as in FIG. 1, and description thereof will be omitted.

The phase error detector FC is a matched filter M
It is connected only to the output of F and the output of the correlation power calculation unit PW, and is not connected to the timing detection unit TDP.

FIG. 6 shows a phase error detector FC according to the second embodiment.
FIG. 7 is a block diagram showing a matched filter MF and a correlation power calculator PW.

The phase error detection section FC has a peak detection section 610 to which the output of the correlation power calculation section PW for obtaining the correlation power (signal power) of the matched filter output Spsc is inputted. The peak detection section 610 is a correlation power calculation section. The correlation power calculated by PW is subjected to threshold processing to detect the peak position. This peak position is substantially equal to the first reception timing detected by the timing detection unit TDP.

The output of the peak detector 610 is input to the clock generator 620, and the clock generator 620 continuously generates the clock CLK2 at the timing of the peak position. Clock CLK2 is substantially equal to clock CLK1.

The phase error detecting section FC further has two-stage sample-hold circuits 630 and 640, and these sample-hold circuits 630 and 640 hold the matched filter output Spsc in synchronization with the clock CLK2. The outputs of the sample and hold circuits 630 and 640 are input to the inter-slot phase error detector 650.

One output Spsc is held in the sample and hold circuit 630 at the slot timing, transferred to the sample and hold circuit 640 at the next slot timing, and the correlation output Sps is output at the new slot timing.
Hold c.

Therefore, the sample hold circuit 640 outputs the correlation output S one slot after the sample hold circuit 630.
psc is output to inter-slot phase error detection section 650.

Thus, the inter-slot phase error detecting section 6
Correlation outputs at the peak positions of two consecutive slots are input in parallel to 50.

The inter-slot phase error detecting section 650 detects a phase error by differential detection similarly to the inter-slot phase error detecting section 320 of the first embodiment, and inputs a reference signal to the frequency control section 240. Frequency control section 240 generates a control signal for temperature-compensated crystal oscillator 250 (FIG. 1) based on the reference signal, and adjusts the local oscillation frequency of the mobile station so as to eliminate the frequency deviation corresponding to the phase error.

If the peak position is detected without using the timing detection unit TDP as described above, the first cell search in the initial cell search can be performed.
Frequency control can be started before the stage (slot synchronization) is completed, and the frequency can be adjusted earlier. This can prevent erroneous cell detection due to frequency deviation.

FIG. 7 is a flowchart showing the processing of the second embodiment.

In the initial cell search, the first stage (slot synchronization: step S701) and the second stage (frame synchronization and identification of scramble code group: step S701)
702), the third stage (scramble code identification: step S703) is sequentially executed, and a peak is detected for the matched filter output for each slot in the middle of the first stage (step S704). The phase error between the slots is detected for the signal after despreading of the detected peak point, and frequency control is performed (step S705).

After specifying the scramble code, frequency control based on the common pilot channel CPICH is executed (step S706), and thereafter, transmission / reception processing with a better local oscillation frequency is executed (step S70).
7). Note that, instead of the common pilot channel CPICH, another common control channel may be used as a base. [Third embodiment]

FIG. 8 is a block diagram showing a cell search block according to the third embodiment and the connection relationship between the cell search block, FC block and AFC block. The overall configuration of the mobile station (FIG. 1) is the same as in the first embodiment, and the connection relationship between the cell search block and the FC block is different from the first embodiment.

In FIG. 8, the connection relationship between the cell search block and the phase error detector FC differs from that of the first embodiment.
Other parts are the same. Therefore, parts other than the phase error detection unit FC are denoted by the same reference numerals as in FIG. 1, and description thereof will be omitted.

The phase error detector FC is a matched filter M
F of the first layer matched filter MF1 (“Spc”)
Is assigned. ), And the timing detector T
Not connected to DP.

FIG. 9 shows a phase error detector FC according to the third embodiment.
FIG. 7 is a block diagram showing a matched filter MF.

The phase error detector FC has a correlation power calculator 900 to which the output Spc of the first layer matched filter MF1 is input, and a peak detector 910 to which the output of the correlation power calculator 900 is input. , Correlated power calculator 900
Calculates the signal power (absolute value) of the output Spc to determine the correlation power. The peak detecting section 910 is provided for the correlation power calculating section 90.
The correlation power calculated at 0 is subjected to threshold processing to detect the peak position.

In FIG. 10, matched filter MF1
Is the number of taps of m, the peak interval Tslot1 of the output Spc of the matched filter MF1 is equal to (Tslot / m).

The output of the peak detector 910 is input to the clock generator 920, and the clock generator 920 continuously generates the clock CLK3 at the timing of the peak position.

As shown in FIG. 10, a plurality (m) of correlation peaks can be detected from the MF1 output Spc within one symbol period of the first synchronization channel P-SCH, and the interval (Tslot1) between the correlation peaks is one. Since it is within the symbol, it is called a sub-symbol here.

The phase error detecting section FC further has two stages of sample and hold circuits 930 and 940, and these sample and hold circuits 930 and 940 hold the output Spc in synchronization with the clock CLK3. The outputs of the sample and hold circuits 930 and 940 are input to the inter-subsymbol phase error detection section 950.

One output Spc is held in the sample hold circuit 930 at the subsymbol timing, transferred to the sample hold circuit 940 at the next subsymbol timing, and holds the correlation output Spc at the new subsymbol timing.

Accordingly, the sample and hold circuit 940 outputs the correlation output Spc after one subsymbol of the sample and hold circuit 300 to the inter-symbol phase error detection section 950.

As a result, the correlation output at the peak position of two consecutive sub-symbols is input to the inter-sub-symbol phase error detection section 950 in parallel.

The inter-symbol phase error detecting section 950 detects a phase error by differential detection similarly to the inter-slot phase error detecting section 320 of the first embodiment, and inputs a reference signal to the frequency control section 240. Frequency control section 240 generates a control signal for temperature-compensated crystal oscillator 250 based on the reference signal, and adjusts the local oscillation frequency of the mobile station so as to eliminate the frequency deviation. Here, the sub-symbol is within one symbol, and one sub-symbol is selected from a plurality of sub-symbols.
It also includes phase error detection between sub-symbols, where some sub-symbols are thinned.

As described above, the output Sp of the first layer matched filter MF1 is not used without using the timing detection unit TDP.
If the peak position of c is detected, the frequency can be adjusted earlier than in the second embodiment. This can prevent erroneous cell detection due to frequency deviation.

Further, since the period Tslot1 is short (1 / m) of Tslot, the detected phase error is smaller than in the first and second embodiments based on the matched filter output Spsc and falls within the adjustment range. Probability is high. Therefore, frequency adjustment is easy. The frequency adjustment range is usually within the phase difference (± π / 4), and beyond this range, a separate parameter is required to determine the adjustment direction.

Generally, there is a high possibility that the frequency deviation becomes large immediately after the mobile station starts receiving, and it is often preferable to perform frequency control by the output Spc of the first layer matched filter MF1 of the third embodiment.

If the calculation by correlation power calculation section 900 is performed by correlation power calculation section PW, correlation power calculation section 900 can be omitted.

FIG. 11 is a flowchart showing the processing of the third embodiment.

In the initial cell search, a first stage (slot synchronization: step S1001), a second stage (frame synchronization and identification of a scramble code group: step S1002), and a third stage (identification of a scramble code:
Step S1003) is sequentially executed, and in the middle of the first stage, a correlation output is extracted from the output of the matched filter MF1 (step S1004), and a correlation peak of the MF1 for each slot is detected (step S100).
5). Here, a phase error between a plurality of correlation peaks in one symbol is detected, and frequency control is performed (step S100).
6).

After specifying the scramble code, frequency control based on the common pilot channel CPICH is executed (step S1007), and transmission / reception processing with a better local oscillation frequency is executed thereafter (step S1).
008). Note that the common pilot channel CPICH
Alternatively, it may be based on another common control channel.

In the third embodiment, the output of MF1 is simply used. However, MF2 is further divided into a plurality of partial correlation matched filters, and the output (excluding the final output of MF2) is used. Similarly, it is also possible to detect a phase error between sub-symbol correlation (partial correlation) outputs and make a frequency judgment based on the phase error. Fourth Embodiment FIG. 12 is a block diagram showing a cell search block and a connection relationship between a cell search block, an FC block, and an AFC block in a fourth embodiment. The overall configuration of the mobile station (FIG. 1) is the same as that of the first embodiment, and the connection between the cell search block and the FC block is different from that of the first embodiment.

In FIG. 12, the connection relationship between the cell search block and the phase error detector FC is different from that of the first embodiment, and the other parts are the same. Therefore, the phase error detection unit F
Portions other than C are denoted by the same reference numerals as in FIG. 1 and description thereof is omitted.

The phase error detector FC is connected to the output Spc of the first layer matched filter MF1 of the matched filter MF and the output Spsc of the matched filter MF, and is not connected to the timing detector TDP.

The fourth embodiment has a configuration for selectively implementing the second and third embodiments.

FIG. 13 shows a phase error detector F of the fourth embodiment.
FIG. 4 is a block diagram showing C together with a matched filter MF.

The phase error detector FC outputs the output Spc of the first layer matched filter MF1 and the matched filter MF
Of the multiplexer 1210 to which the output Spsc is input, and the output of the multiplexer 1210 is input to the correlation power calculator 1220. That is, the correlation power calculator 1
An output Spsc or Spc is selectively input to 220. The correlation power calculator 1220 outputs the output Spsc or S
The signal power (absolute value) of pc is calculated to obtain the correlation power. Note that, inside the correlation power calculation unit 1220, the same calculation as that of the correlation power calculation unit PW is performed.

The output of the correlation power calculator 1220 is input to a peak detector 1230. The peak detector 1230 performs threshold processing on the correlation power calculated by the correlation power calculator 1220, and detects the peak position.

The output of the peak detector 1230 is input to the clock generator 1240, and the clock generator 1240 continuously generates the clock CLK4 at the timing of the peak position. Clock CLK4 is equal to clock CLK2 or CLK3.

The phase error detecting section FC further has two stages of sample and hold circuits 1250 and 1260, and these sample and hold circuits 1250 and 1260
The output Spsc or Spc is held in synchronization with K4. The outputs of the sample and hold circuits 1250 and 1260 are output from the
Input to 0.

When the output Spsc is selected for the multiplexer 1210, the clock generator 1240 generates the clock CLK4 (CLK
2), and when the output Spc is selected, Tslot
A clock CLK4 having a period of 1 = (Tslot / m) is generated.

The output of the multiplexer is sampled and held 1250 at slot or subsymbol timing.
, And transferred to the sample and hold circuit 1260 at the next slot or sub-symbol timing, and hold the correlation output Spsc or Spc at the new slot or sub-symbol timing. Therefore, the sample and hold circuit 1260 outputs the correlation output Spsc or Spc after one slot or sub-symbol of the sample and hold circuit 1250 to the inter-slot or inter-symbol phase error detection unit 1270.

Thus, correlation outputs at two consecutive peak positions are input in parallel to inter-slot or inter-symbol phase error detection section 1270.

The inter-slot or inter-symbol phase error detection section 1270 detects a phase error by differential detection similarly to the inter-slot phase error detection section 320 of the first embodiment, and inputs a reference signal to the frequency control section 240. Frequency control section 240 generates a control signal for temperature-compensated crystal oscillator 250 (FIG. 1) based on the reference signal, and adjusts the local oscillation frequency of the mobile station so as to eliminate the frequency deviation corresponding to the phase error.

As described above, if the outputs Spsc and Spc are selectively used for frequency control, optimal frequency control according to the situation can be realized. For example, immediately after the start of transmission / reception of the mobile station, the frequency deviation becomes relatively large, so the output Spc is used, and thereafter, the control is switched to the control using the output Spsc. This can prevent erroneous cell detection due to frequency deviation.

FIG. 14 is a flowchart showing the processing of the fourth embodiment.

In the initial cell search, the first stage (slot synchronization: step S1301), the second stage (frame synchronization and identification of a scramble code group: step S1302), and the third stage (identification of a scramble code:
Step S1303) is sequentially executed, and in the middle of the first stage, a selection process (step S1304) is executed.
From here, step S130 which is the processing of the second embodiment
5, S1306, or selectively proceed to steps S1307, S1308, and S1309, which are the processes of the third embodiment.

In the processing of the second embodiment, first, a peak is detected for the matched filter output for each slot (step S1305), and a phase error between slots is detected for the signal after despreading of the detected peak point. Frequency control is performed (step S1306).

On the other hand, in the processing of the third embodiment, a correlation output is extracted from the output of the matched filter MF1 (step S1307), and a correlation peak of the MF1 for each slot is detected (step S1308). Here, a phase error between a plurality of correlation peaks is detected, and frequency control is performed (step S1309).

Next, one of the processing result of the second embodiment and the processing result of the third embodiment is selected (step S13).
10).

After specifying the scramble code, frequency control based on the common pilot channel CPICH is executed (step S1311), and transmission / reception processing with a better local oscillation frequency is executed thereafter (step S1).
312). Note that the common pilot channel CPICH
Alternatively, it may be based on another common control channel.

In the above embodiment, a phase error is detected by differential detection to generate a frequency control reference signal. However, other phase error detection methods and frequency control methods, such as Y. Wang and T.W. Ottoson's paper "INITIAL FREQNCY ACQ"
UISATION IN W-CDMA "(IEEEV
vehicle Technology Conference
nce 1999).

[0123]

According to the present invention, erroneous cell detection due to a frequency deviation can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall block diagram showing a first embodiment of a mobile station in a W-CDMA communication system according to the present invention.

FIG. 2 is a block diagram illustrating a connection relationship between a cell search block and an AFC block in FIG. 1;

FIG. 3 is a block diagram illustrating a phase error detection unit of FIG. 2;

FIG. 4 is a flowchart illustrating a first embodiment of a frequency control method according to the present invention.

FIG. 5 is a block diagram showing a connection relationship between a cell search block and an AFC block in a second embodiment of the mobile station.

FIG. 6 is a block diagram illustrating a phase error detection unit of FIG. 5;

FIG. 7 is a flowchart showing a second embodiment of the frequency control method according to the present invention.

FIG. 8 is a block diagram illustrating a connection relationship between a cell search block and an AFC block in a third embodiment of the mobile station.

FIG. 9 is a block diagram illustrating a phase error detection unit of FIG. 8;

FIG. 10 is a graph showing a comparison between the output Spsc of the matched filter MF and the output Spc of the first-layer matched filter MF1.

FIG. 11 is a flowchart showing a third embodiment of the frequency control method according to the present invention.

FIG. 12 is a block diagram showing a connection relationship between a cell search block and an AFC block in a fourth embodiment of the mobile station.

FIG. 13 is a block diagram illustrating a phase error detection unit of FIG. 12;

FIG. 14 is a flowchart illustrating a frequency control method according to a fourth embodiment of the present invention.

FIG. 15 is a conceptual diagram showing a general transmission signal frame configuration of a three-stage cell search method.

FIG. 16 is a block diagram showing the matched filter of FIG. 2;

FIG. 17 is a block diagram illustrating a sliding correlator unit of FIG. 2;

FIG. 18 is a block diagram illustrating one sliding correlator in FIG. 17;

FIG. 19 is a flowchart showing a conventional frequency control method.

[Explanation of symbols]

CLK1, CLK2, CLK3, CLK4 Clock GC [i, j] Scramble code PSC First synchronization code SSC [i] Second synchronization code MF Matched filter SC Sliding correlator AFC Frequency controller FC Phase error detector TDP Timing detector 1210 Multiplexers 600, 900, 1220 Correlation power calculator 2312 Despread demodulator 610, 910, 1230 Peak detector 620, 920, 1240 Clock generator 300, 310, 630, 640, 930, 940, 1
250, 1260 Sample and hold circuit 320, 650 Inter-slot phase error detector 950 Inter-subsymbol phase error detector 1270 Inter-slot or inter-symbol phase error detector

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (10)

[Claims] 1. A first synchronization code (search code) common to all base stations and a scrambling code specifying a base station are set, and these scrambling codes are divided into a plurality of scrambling code groups, and each scrambling code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code and a second synchronization code composed of the first synchronization channel (search channel) and the second synchronization code are set by the base station. The mobile station transmits a synchronization channel (search channel), performs a correlation operation on the received signal using a first synchronization code, and detects a first reception timing (slot synchronization) based on the result of the correlation operation. Together with a first step of generating a despread signal of the received signal;
Performing a correlation operation using a second synchronization code at the first reception timing, detecting a second reception timing (frame synchronization) based on the correlation operation result, and specifying a scramble code group; A correlation operation is performed using a plurality of scrambling codes included in the determined scrambling code group, and a third step of specifying one scrambling code is performed to perform an initial cell search, whereby the mobile station should receive a signal. In a frequency control method for a mobile station in a W-CDMA communication system in which a base station is specified and then communication between the mobile station and the base station is performed using a plurality of channels, after completion of the first step, a correlation calculation result based on a first synchronization code is obtained. It detects the phase error between the slots and eliminates the frequency deviation corresponding to this phase error. Frequency control method characterized by adjusting the local oscillator frequency of the mobile station. 2. A first synchronization code (search code) common to all base stations and a scrambling code specifying a base station are set, and these scrambling codes are divided into a plurality of scrambling code groups, and each scrambling code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code (search channel) composed of the first synchronization code and a second synchronization code composed of the second synchronization code is set by the base station. A synchronization channel (search channel) is transmitted. The mobile station performs a correlation operation on the received signal using the first synchronization code, cyclically integrates the signal power of the correlation operation result, and based on the cyclic integration result. A first step of detecting a first reception timing (slot synchronization) and generating a despread signal of the received signal; Performing a correlation operation on the received signal using the second synchronization code at the first reception timing;
A second step of detecting a second reception timing (frame synchronization) based on the result of the correlation operation and specifying a scramble code group, and performing a correlation operation using a plurality of scramble codes included in the specified scramble code group. And performing the initial cell search by the third step of specifying one scrambling code, thereby specifying the base station from which the mobile station should receive the signal, and then performing communication between the mobile station and the base station using a plurality of channels. In the frequency control method of a mobile station in the W-CDMA communication system, a peak of signal power of the correlation operation result is detected before detecting a first reception timing in a first step of cell search, and a plurality of peaks are detected at the timing of the peak. Detects the phase error of the correlation output at the peak position and responds to this phase error Frequency control method characterized by adjusting the local oscillator frequency of the mobile station so as to eliminate the frequency deviation that. 3. A first synchronization code (search code) common to all base stations and a scrambling code specifying a base station are set, and these scrambling codes are divided into a plurality of scrambling code groups, and each scrambling code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code and a second synchronization code composed of the first synchronization channel (search channel) and the second synchronization code are set by the base station. A synchronization channel (search channel) is transmitted. The mobile station performs a correlation operation on the received signal using the first synchronization code, cyclically integrates the signal power of the correlation operation result, and based on the cyclic integration result. A first step of detecting a first reception timing (slot synchronization) and generating a despread signal of the received signal; Performing a correlation operation on the received signal using the second synchronization code at the first reception timing;
A second step of detecting a second reception timing (frame synchronization) based on the result of the correlation operation and specifying a scramble code group, and performing a correlation operation using a plurality of scramble codes included in the specified scramble code group. And performing the initial cell search by the third step of specifying one scrambling code, thereby specifying the base station from which the mobile station should receive the signal, and then performing communication between the mobile station and the base station using a plurality of channels. In the frequency control method for a mobile station in the W-CDMA communication system, the correlation calculation in the first step is performed hierarchically by a series of matched filters in a plurality of layers, and the first reception timing detection in the first step of the cell search is performed. Before, the result of the correlation operation before the last layer of the matched filter (hereinafter referred to as “part The mobile station detects a peak of signal power of "correlation"), detects a phase error between partial correlations at a plurality of peak positions at the timing of the peak, and eliminates a frequency deviation corresponding to the phase error. A frequency control method comprising: adjusting a local oscillation frequency of the control signal. 4. A first synchronization code (search code) common to all base stations and a scramble code specifying a base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code (search channel) composed of the first synchronization code and a second synchronization code composed of the second synchronization code is set by the base station. A synchronization channel (search channel) is transmitted. The mobile station performs a correlation operation on the received signal using the first synchronization code, cyclically integrates the signal power of the correlation operation result, and based on the cyclic integration result. A first step of detecting a first reception timing (slot synchronization) and generating a despread signal of the received signal; Performing a correlation operation on the received signal using the second synchronization code at the first reception timing;
A second step of detecting a second reception timing (frame synchronization) based on the result of the correlation operation and specifying a scramble code group, and performing a correlation operation using a plurality of scramble codes included in the specified scramble code group. And performing the initial cell search by the third step of specifying one scrambling code, thereby specifying the base station from which the mobile station should receive the signal, and then performing communication between the mobile station and the base station using a plurality of channels. In the frequency control method of the mobile station in the W-CDMA communication system, the correlation operation of the first step is performed hierarchically by a series of matched filters of a plurality of layers, and the first step of the first step is performed.
Before detecting the reception timing, the peak of the signal power of the last layer of the matched filter (hereinafter, referred to as “all correlation”) or the correlation operation result before the last layer (hereinafter, referred to as “partial correlation”) is detected. Frequency control for selectively detecting a phase error of a total correlation or a phase error of a partial correlation at a plurality of peak positions and adjusting a local oscillation frequency of a mobile station so as to eliminate a frequency deviation corresponding to the phase error. Method. 5. The frequency control method according to claim 1, wherein the phase error is calculated by differential detection. 6. A first synchronization code (search code) common to all base stations and a scrambling code specifying a base station are set, and these scrambling codes are divided into a plurality of scrambling code groups, and each scrambling code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code (search channel) composed of the first synchronization code and a second synchronization code composed of the second synchronization code is set by the base station. The mobile station transmits a synchronization channel (search channel), performs a correlation operation on the received signal using a first synchronization code, and detects a first reception timing (slot synchronization) based on the result of the correlation operation. Together with a first step of generating a despread signal of the received signal;
Performing a correlation operation using a second synchronization code at the first reception timing, detecting a second reception timing (frame synchronization) based on the correlation operation result, and specifying a scramble code group; A correlation operation is performed using a plurality of scrambling codes included in the determined scrambling code group, and a third step of specifying one scrambling code is performed to perform an initial cell search, whereby the mobile station should receive a signal. In a mobile station in the W-CDMA communication system in which a base station is specified and then communication between the mobile station and the base station is performed using a plurality of channels, a matched filter that executes a first-step correlation operation, and an output of the matched filter are input. And a correlation power calculator for calculating the correlation power. An adder to which the output of the section is input; and a memory that inputs the output of the adder to a memory that holds the output at a slot cycle, and that output is fed back to the adder, whereby the correlation power is accumulated by the adder. A timing detection unit for detecting a first reception timing based on an output of the memory; a plurality of outputs of the matched filter are taken in at the first reception timing detected by the timing detection unit; A phase error detection unit that detects a phase error, and a frequency control unit that controls a local oscillation frequency of the mobile station so as to eliminate a frequency deviation corresponding to the phase error detected by the phase error detection unit. A mobile station, characterized in that: 7. A first synchronization code (search code) common to all base stations and a scramble code specifying a base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code and a second synchronization code composed of the first synchronization channel (search channel) and the second synchronization code are set by the base station. The mobile station transmits a synchronization channel (search channel), performs a correlation operation on the received signal using a first synchronization code, and detects a first reception timing (slot synchronization) based on the result of the correlation operation. Together with a first step of generating a despread signal of the received signal;
Performing a correlation operation using a second synchronization code at the first reception timing, detecting a second reception timing (frame synchronization) based on the correlation operation result, and specifying a scramble code group; A correlation operation is performed using a plurality of scrambling codes included in the determined scrambling code group, and a third step of specifying one scrambling code is performed to perform an initial cell search, whereby the mobile station should receive a signal. In a mobile station in the W-CDMA communication system in which a base station is specified and then communication between the mobile station and the base station is performed using a plurality of channels, a matched filter that executes a first-step correlation operation, and an output of the matched filter are input. And a correlation power calculator for calculating the correlation power. An adder to which the output of the section is input; and a memory that inputs the output of the adder to a memory that holds the output at a slot cycle, and that output is fed back to the adder, whereby the correlation power is accumulated by the adder. A timing detector for detecting a first reception timing based on an output of the memory; a correlation power calculator for receiving an output of the matched filter and calculating a correlation power; and a correlation calculated by the correlation power calculator. A peak detector that detects a peak position of power, and a plurality of outputs of the matched filter are captured at timing of the peak position detected by the peak detector,
A frequency control unit including a phase error detection unit that detects a phase error of a correlation calculation result of a plurality of slots; and a frequency deviation corresponding to the phase error detected by the phase error detection unit of the frequency control unit. And a frequency control unit for controlling a local oscillation frequency of the mobile station. 8. A first synchronization code (search code) common to all base stations and a scramble code for specifying the base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code and a second synchronization code composed of the first synchronization channel (search channel) and the second synchronization code are set by the base station. The mobile station transmits a synchronization channel (search channel), performs a correlation operation on the received signal using a first synchronization code, and detects a first reception timing (slot synchronization) based on the result of the correlation operation. Together with a first step of generating a despread signal of the received signal;
Performing a correlation operation using a second synchronization code at the first reception timing, detecting a second reception timing (frame synchronization) based on the correlation operation result, and specifying a scramble code group; A correlation operation is performed using a plurality of scrambling codes included in the determined scrambling code group, and a third step of specifying one scrambling code is performed to perform an initial cell search, whereby the mobile station should receive a signal. A mobile station in a W-CDMA communication system in which a base station is specified, and thereafter the mobile station and the base station communicate with each other through a plurality of channels; The matched filter output of the last layer of the matched filter is input and its correlation power A correlation power calculator for calculating, an adder to which the output of the correlation power calculator is input, and an input to a memory holding the output of the adder in a slot cycle, and the output is fed back to the adder, whereby A memory for accumulating the correlation power by the adder; a timing detector for detecting a first reception timing based on an output of the memory; and an output of a matched filter before the last layer (hereinafter, referred to as “partial correlation”). A correlation power calculator for calculating the correlation power which is input, a peak detector for detecting a peak position of the correlation power calculated by the correlation power calculator, and a timing of the peak position detected by the peak detector. A frequency control unit including a plurality of partial correlations and detecting a phase error between partial correlations at a plurality of peak positions; A mobile station, comprising: a frequency control unit that controls a local oscillation frequency of the mobile station so as to eliminate a frequency deviation corresponding to a phase error detected by a phase error detection unit of the control unit. 9. A first synchronization code (search code) common to all base stations and a scramble code specifying a base station are set, and these scramble codes are divided into a plurality of scramble code groups, and each scramble code group is set. A combination of a second synchronization code (search code) for specifying the first synchronization code and a second synchronization code composed of the first synchronization channel (search channel) and the second synchronization code are set by the base station. The mobile station transmits a synchronization channel (search channel), performs a correlation operation on the received signal using a first synchronization code, and detects a first reception timing (slot synchronization) based on the result of the correlation operation. Together with a first step of generating a despread signal of the received signal;
Performing a correlation operation using a second synchronization code at the first reception timing, detecting a second reception timing (frame synchronization) based on the correlation operation result, and specifying a scramble code group; A correlation operation is performed using a plurality of scrambling codes included in the determined scrambling code group, and a third step of specifying one scrambling code is performed to perform an initial cell search, whereby the mobile station should receive a signal. A mobile station in a W-CDMA communication system in which a base station is specified, and thereafter, communication between the mobile station and the base station is performed using a plurality of channels, a multi-layer serial matched filter that executes a first-step correlation operation; The matched filter output of the last layer of the matched filter and the A multiplexer that receives the output of the pseudo-filter and selectively outputs these outputs; a correlation power calculator that receives the output of the matched filter of the last layer and calculates the correlation power; and an output of the correlation power calculator. An input adder, a memory for holding an output of the adder in a slot cycle, the output of which is fed back to the adder, whereby the correlation power is accumulated by the adder; and an output of the memory. A timing detection unit that detects a first reception timing based on the output of the matched filter of the last layer (hereinafter, “all correlations”).
That. ) And the output of the matched filter before the last layer (hereinafter, referred to as “partial correlation”), and a multiplexer for selectively outputting these outputs, and a correlation power calculator for calculating the correlation power of the output of the multiplexer. When,
A peak detector for detecting a peak position of the correlation power calculated by the correlation power calculator; and a plurality of outputs of the multiplexer at a timing of the peak position detected by the peak detector. A frequency control unit having a phase error detection unit for detecting a phase error; and a local oscillation frequency of the mobile station so as to eliminate a frequency deviation corresponding to the phase error detected by the phase error detection unit of the frequency control unit. And a frequency control unit for controlling the mobile station. 10. The mobile station according to claim 6, wherein the phase error detection unit calculates the phase error by delay detection.