JP3158821B2 - CDMA mobile communication system and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a code division multiple access (CDMA: Code Div.) Using spread spectrum communication.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and particularly to a CDM excellent in throughput of a traffic channel (communication channel for data transmission).
A mobile communication system, a base station, and a mobile station device.

[0002]

2. Description of the Related Art In a CDMA cellular mobile radio communication system using spread spectrum, for example, as shown in FIG.
It manages all the mobile stations 101 to 106 existing in 15 and 16 and performs communication between the mobile stations via the base station. The radio network controller 17 is connected as an upper layer of the base station, and performs exchange control between the mobile station that has requested communication and the partner station. In a communication line (forward link) from a base station to a mobile station, a pilot signal is constantly transmitted. The pilot signal is an important reference signal for the mobile station, and the mobile station uses this as a reference signal to perform data demodulation, power control, handoff, and the like.

[0003] For example, in the case of the mobile station 103 located near the cell boundary in FIG.
This is realized by comparing the received power of the pilot signal from the base station 11 having jurisdiction over the received power of the pilot signal from the base station 12 having jurisdiction over the adjacent cell 15 and switching the connection to the larger base station. .

FIG. 2 shows a general configuration of a base station transmitting section and a mobile station receiving section. The pilot signal is a data (generally all “0” or all “1”) generated by the pilot data generator 21 in the pilot channel.
Is generated by performing digital phase modulation on the known digital sequence of the

In the traffic channel, the data signals output from the data generation unit 27 and addressed to the mobile stations 1 to n are phase-modulated by the phase modulation unit 22 and then spread in spectrum in synchronization with the pilot signal. The synchronization channel is a dedicated channel for frame synchronization. Synchronization with the pilot channel, synchronization channel data is generated by the synchronization channel data unit 25, and this is phase-modulated by the phase modulation unit 22.
In the synchronization channel, the synchronization channel data is transmitted as a frame configuration having a unique word as a header.

[0006] The unique word is a special digital sequence, and the receiving side captures the unique word by frame synchronization processing in the demodulation section, and correctly detects the head of the frame from the header phase at the time of capture, so that the data is transmitted at an appropriate timing. Can be demodulated.

The output of each channel is supplied to a spread spectrum unit 2
3 and are multiplexed by the multiplexing unit 24. In each of the spread spectrum units 23, pilot, traffic, and synchronization channels are distinguished by using an orthogonal code (a pseudo random code multiplied by a Walsh code). The signal after the spread spectrum is carrier-modulated by the carrier modulation unit 28 and transmitted wirelessly via the antenna 29.

On the other hand, the mobile station receives a radio signal from the base station via the antenna 30 and demodulates the signal by the carrier demodulation section 31. Then, the spectrum despreading section 32 has the same phase as that of the base station and the phase is synchronized. Despreading is performed using orthogonal codes. In this despreading, by using the orthogonal code assigned to the base station, the pilot, synchronization and traffic channels can be easily selected and extracted. The output (pilot channel, traffic channel, synchronization channel) of each channel after spectrum despreading is two-dimensional baseband signals I and Q. Data demodulation is performed by the quasi-synchronous detection demodulation unit 3
3, by realizing synchronous demodulation of the traffic channel with reference to the phase of the pilot signal.

In general, a mobile station needs to know the absolute phase of a pilot signal when demodulating data. The quasi-synchronous detection demodulation is a useful means for realizing this purpose, and uses a PLL (Phase Locked Loop) to reproduce a frequency and a phase synchronized with a received signal and perform detection demodulation. In the frame synchronization unit 34, the quasi-synchronous detection and demodulation unit 3
3 to output a frame head detection signal by searching for a unique word from the synchronous channel after the phase correction output from 3. With the frame head detection signal, the quasi-synchronous detection demodulation can restore received data at a correct timing.

The prior art relating to this type of apparatus includes, for example, US Patent QUALCOMM: System and Method for Generating Signal Waveforms in a CDM Cellular Telephone System (SYSTEM ANDMETHOD).
FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULA
R TELEPHONE SYSTEM, USPATENT NO.5103459, AP
R. 7, 1992).

[0011]

However, in the prior art, as shown in FIG. 2, since the frame synchronization channel occupies one traffic channel, the loss of the number of simultaneous calls and the throughput are reduced. Causes a decrease in

The above problem can be solved by a method of inserting a unique word only into a pilot channel in a base station transmitter, as will be described in detail in an embodiment of the present invention. In this case, if the pilot signal contains data whose phase changes irregularly like a unique word, a phase error larger than the actual one is output as described below, and the PLL characteristic is degraded. Problems occur.

FIG. 3 shows an example of a pilot frame structure in which a unique word is inserted. Here, pilot signals I and Q each constitute a frame consisting of 960 bits, of which a unique word as a special sequence is allocated to the first 32 bits, and pilot data is allocated to the rest.

For a frame having such a configuration,
For example, when the QPSK modulation shown in FIG. 4 is performed, pilot data (all “0”) is transmitted as signal point A, and a unique word is transmitted as signal point A or C. Therefore, when a unique word is received, as shown in FIG. 4, the reception points after normalization are P for "0" and P 'for "1".

Here, the reason why the reception point does not completely coincide with the signal point A or C is that the transmission path noise, fading, PL
This is due to the influence of a deterioration factor due to a phase control error of L or the like.
That is, P ′ is a reception point that is not originally expected as pilot data, and the phase error of the reception point P ′ with respect to the reference signal point A becomes close to 180 degrees. This is PLL
May cause malfunction.

In the prior art, the above problem can be solved to some extent by making the time constant of the loop filter sufficiently long and slowing down the followability to a sudden phase change, but the effect of the phase error is completely eliminated. It cannot be eliminated.
For this reason, the decoding error rate characteristic deteriorates, and if the time constant is made too long, the followability to the phase fluctuation of the received signal becomes poor. That is, the conventional quasi-synchronous detection and demodulation device has a problem that it is weak to a large phase fluctuation and it is difficult to optimally set a PLL parameter.

An object of the present invention is to provide a CDMA mobile communication system in which a decrease in throughput of a traffic channel is prevented.

[0018] Another object of the present invention is to provide a mobile station that can receive a large amount of phase fluctuation even if there is a large phase variation in the received signal.
An object of the present invention is to provide a CDMA mobile communication system free from LL malfunction and characteristic deterioration.

Another object of the present invention is to provide a novel configuration of a base station and a mobile station in a CDMA mobile communication system.

[0020]

In order to achieve the above object, in a CDMA mobile communication system according to the present invention, a base station inserts a unique word for frame synchronization into a pilot serving as a reference signal for each frame period. The pilot signal and the data of the traffic channel are phase-modulated and spectrum-spread, respectively, multiplexed, and transmitted in the air. On the other hand, each mobile station extracts a frame synchronization signal from a pilot channel received signal and demodulates data from a traffic channel received signal based on the frame synchronization signal.

More specifically, the receiving section of each mobile station includes a quasi-synchronous detection and demodulation device including a synchronization state monitoring means, a switching control means, and a phase error determination means. Whether or not the frequency and phase between the received signals are synchronized is constantly monitored, and appropriate phase difference correction is performed according to the state.

When the phase difference between the received signal and the reference signal in the apparatus is equal to or greater than a set value, the synchronization state monitoring means considers the state to be an error state and sets the average error rate to be smaller than a preset allowable value. If it is smaller, it is determined to be synchronous, otherwise it is determined to be asynchronous. In the synchronous state, the switching control means determines whether or not the phase difference between the received signal and the internal reference signal is equal to or greater than a set value by the phase error determining means. PLL after inverting the phase of the received signal
Is operated, and if not, a mode in which normal processing is performed by using the phase difference as an input to the PLL is selected. on the other hand,
When in the asynchronous state, the switching control means selects the normal pull-in operation mode until the state is again synchronized.

[0023]

According to the structure of the present invention, in the transmitting section of the base station, it is sufficient to insert a unique word only in the pilot channel, so that a synchronization channel is not required, and as a result, the throughput can be improved. In the receiving section of the mobile station,
Higher transmit power than the traffic channel (typically 10d
B or more), frame synchronization can be achieved using a pilot channel output at a higher S / N than before.
Data demodulation can be performed by (signal-to-noise power ratio).

[0024]

Embodiments of a CDMA mobile communication system according to the present invention will be described below with reference to the drawings.

FIG. 5 shows a configuration of a transmitting section of a base station and a receiving section of a mobile station, which are main parts of a CDMA mobile communication system according to the present invention. In the figure, the transmitting unit of the base station inserts the unique word generated by the unique word inserting unit 26 into the pilot data generated from the data generating unit 21 for each frame cycle in the pilot channel (see FIG. 3). Thereafter, the circuits 22 and 23 perform phase modulation and spectrum spreading. The traffic channel is the same as that of the conventional system. The data generator 27 generates data addressed to each of the mobile stations 1 to n, and the circuits 22 and 23 perform phase modulation and spread spectrum. The output of the pilot channel and the output of the traffic channel are synchronously multiplexed by a multiplexing circuit 24. The multiplexed signal is carrier-modulated by a modulation circuit 28, and then transmitted as a radio signal from an antenna 29. .

According to the present invention, the transmitting section of the base station has a frame structure in which a unique word is inserted into a pilot, so that there is no need to prepare a channel dedicated to frame synchronization unlike the conventional system. For this reason, each mobile station can acquire frame synchronization with the pilot, and as a result, it is possible to eliminate loss of the traffic channel.

In the receiving section of the mobile station, the radio signal transmitted from the base station is received by the antenna 30, carrier-demodulated by the demodulation circuit 31, and then despread by the spectrum despreading circuit 32. The despread output is a two-dimensional baseband signal I, Q
And each channel (pilot ch, traffic c)
h) can be easily selected and extracted by orthogonal codes. The output of each channel is a quasi-synchronous detection demodulation unit 33a.
Is input to The frame synchronization circuit 34 searches for a unique word by using the pilot channel whose phase has been corrected by the quasi-synchronous detection and demodulation unit 33a, and outputs a frame head detection signal to the quasi-synchronous detection and demodulation unit 33a at an appropriate timing. Demodulate the received data.

As described above, in the CDMA modulation and demodulation, since the unique word is mixed in the pilot transmitted by the base station, the quasi-synchronous detection and demodulation on the mobile station side is performed for each frame period caused by the unique word. A large phase change causes a malfunction. This problem can be solved by, for example, configuring the quasi-synchronous detection and demodulation unit 33a as follows.

FIG. 6 shows an example of the configuration of the quasi-coherent detection and demodulation unit. In the figure, Xi and Xq are the spectrum despread outputs of the pilot signal (in which the unique word is inserted), and represent the in-phase component I and the quadrature component Q of the baseband, respectively (see FIG. 5). Pilot despread output Xi, X
q is phase-rotated by the phase correction unit 1 and corrected to Yi and Yq. The amount of phase rotation is determined by the VCO (Voltage Control
lled Oscillator) 7 outputs a value φn (n is a time), more specifically, a signal (COSφ)
n, SINφn).

The outputs Yi and Yq after the phase correction are sent to the amplitude normalizing section 2 as pilot demodulated signals, and the amplitude normalizing section 2 calculates Yi and Yq respectively as the square root of their sum of squares (that is, the distance from the origin). ), The output Y
i ′ and Yq ′ are obtained.

In the present invention, Yi and Yq are input to the frame synchronization 34, and a frame head detection signal is obtained from a pilot signal. Here, the frame head detection signal is a 1-bit width rectangular pulse signal output every time the head bit of the frame arrives, and is input to the data demodulation unit 9. In the phase difference calculating section 3, the amplitude normalized output Y
Calculate the phase difference Δφn between i ′, Yq ′ and the reference signal 4,
Output. Here, the reference signal is a signal expected as an ideal pilot reception signal (a digital sequence of all “0” or all “1”, but it is assumed here that it is all “0”). This corresponds to signal point A. That is, Δφn corresponds to the phase of the reception point P (Yi ′, Yq ′) after normalization with respect to the reference signal point A. As a modulation method, QPSK (Qu
FIG. 4 shows the signal point arrangement.

In the present embodiment, the mobile station includes a synchronization state monitoring unit 10, a switching control unit 11, a phase difference determination unit 12, and a phase difference correction 2 (51). Synchronization status monitor 1
At 0, as will be described in detail later, the value of the phase error is constantly monitored, and the average probability of synchronization (hereinafter, referred to as “synchronization rate”) is estimated based on the value. The determination of synchronous or asynchronous is performed as follows.

That is, if the synchronization rate is equal to or less than a preset allowable value, it is determined that the apparatus is in a synchronous state. Conversely, if the synchronization rate continuously exceeds the allowable value for a certain monitoring period, the apparatus is switched to the asynchronous state. to decide. The out-of-synchronization state usually occurs when an apparatus is initially turned on immediately after being turned on or when synchronization is lost for some reason.

In the synchronous state, the switch is connected to the b side by the switching control unit 11 and the phase difference Δφn signal is input to the phase difference determination unit 12. The phase difference determination unit 12 compares the absolute value of the phase error (Δφn) with π / 2. The phase difference correction circuit 51 sets the phase error to 0 if the absolute value is π / 2 or more.
(Δφn ′ = 0), and otherwise output the original value of the phase error (Δφn ′ = Δφn). By the above-described phase difference determination and correction processing, even if the signal phase is inverted (FIG. 3) due to the unique word (FIG. 5) periodically inserted into the pilot signal, this is forcibly set to 0. In addition, malfunction of the loop filter can be completely prevented. When the absolute value of the phase error is π / 2 or more, the phase difference correction 51
(Δφn ′ = Δφn−180 if Δφn> 0)
Degrees, otherwise Δφn ′ = Δφn + 180 degrees),
Otherwise, the original value of the phase error may be output as it is (Δφn ′ = Δφn). Even in this case, the same effect as above can be obtained. In this case, the reference signal 4 (FIG. 2) equivalently has a unique word inserted for each frame period, and has an advantage that PLL processing can be effectively performed on all data.

On the other hand, in the asynchronous state, the switch is connected to the a side by the switching control unit 11, and the phase error (Δφn) is input to the phase difference correction circuit 5. In this case, the phase difference determination process is not performed, and the normal pull-in process is performed until the synchronization state is established. That is, the processing when the switch is connected to the a side is the same as the conventional processing.

The phase difference correction circuit 5 performs a correction for preventing the reverse control of the PLL. Specifically, as shown in FIG. 7, the value of the phase difference always has the same sign according to the phase rotation direction (positive or negative). by this,
The phase control direction of the PLL can be made the same, and the reverse control can be prevented. For example, when the phase is rotating in the positive direction, Δφn
Is in the range of 0 to 2π, Δφ if rotating in the negative direction
Let n be in the range of 0 to −2π.

The phase error Δφn ′ corrected by the phase difference correction circuit 5 or 51 is input to the loop filter 6. The loop filter 6 is a low-pass filter for removing noise used in an ordinary well-known second-order PLL. The detailed description thereof will be omitted, but the loop filter 6 is unnecessary for a sudden change in phase due to noise or the like. P not to follow
This is for adjusting the response speed of LL. The output of the loop filter is integrated by the VCO 7, whereby a phase rotation amount φn is obtained.

The sine wave generator 8 is for generating COS φn and SIN φn according to the phase rotation amount φn. These signals are used to correct the phase of the despread output of the received pilot signal, as described above. This phase correction is also made to the data despread output of the traffic channel signal. In spread spectrum communication, data is always multiplexed in synchronization with a pilot signal. Therefore, if the phase of the pilot is known, the phase of the data can be known. Therefore, if synchronization is established with respect to the pilot signal, the data signal can be easily demodulated with the same phase. The traffic channel output after the phase correction is demodulated in the data demodulation unit 9 at the timing of the frame head detection signal, and is restored to the received data.

Next, the synchronization status monitor (see FIG. 6) according to the present invention will be described.

As described above, the synchronization state monitoring unit constantly monitors the value of the phase error Δφn, estimates the synchronization rate based on the value, and if the synchronization rate is equal to or less than a preset allowable value, the synchronization state is monitored. If the synchronization rate is continuously higher than the allowable value for a certain monitoring period, the state is determined to be asynchronous.

FIG. 8 shows the specific algorithm. After inputting the phase difference Δφn, it is determined whether or not its absolute value is larger than π / 2.
The input value of (LowPass Filter) is set to “1”, otherwise, the input value of LPF is set to “0”.

Here, the averaging LPF is a well-known first-order digital filter as shown in FIG.
It comprises a multiplier 81, an adder 82, and a delay element 83.
α indicates a gain that determines the response speed of the filter.

By the above operation, for example, when Δφn becomes abnormally large without the PLL being synchronized, the LPF output X
Means that the average value increases with time (it can be estimated that the synchronization rate is small). LPF when PLL is synchronized
The output stays near 0 on average (it can be estimated that the synchronization rate is large). Therefore, when the LPF output value X is equal to or less than the allowable value X0 (X0> 0), the synchronization rate is sufficiently high, and P
When it is determined that the LL is in the synchronous state, the value of the counter provided in the synchronous state monitoring unit is reset to 0, and switching control for the synchronous state is performed (the switch in FIG. 1 is connected to the a side).

On the other hand, when X> X0, the synchronization rate is low,
Since there is a high possibility that the PLL is out of synchronization, it is monitored using a pulse counter whether this state continues for a certain period or more. That is, if X> X0, the counter value i is increased by “1” by counting up, and it is determined whether or not the count result has become larger than the observation period M (bit). If the counter value i is larger than M, it is determined that the state is asynchronous,
The switch (FIG. 1) is connected to the a side by the switching control.

According to the present invention, it is possible to automatically observe the synchronous / asynchronous state in the apparatus according to the present invention.
The values of X0 and M are determined, for example, as follows.

In the asynchronous state, the decoding error rate is statistically 0.
It is considered that the state is "5", and whether the state is "1" or "0" is unknown.
Therefore, it is determined that the possibility of asynchronous operation is high for a half of this value, that is, a value exceeding 0.25, and X0 =
0.25. Also, the parameter α =
0.98. This corresponds to a time constant of 1.59 ms (about 50 bits) at 32 kHz sampling. Here, at least 1 / 0.25 = 4 bits of averaging time is required, which is sufficient. On the other hand, M satisfies the following expression.

[0047]

(Equation 1)

Here, the expected value of the LPF input when the unique word arrives is set to 0.5. N = 0 to 31 correspond to 32 bits of the unique word.

According to the configuration of the above embodiment, the phase difference determination processing is not performed until the synchronization state is determined in the initial PLL pull-in processing.
The LPF input when receiving a unique word is disturbed. Therefore, if the LPF output after observing only M from this point becomes sufficiently smaller than 0.25, it may be determined that the PLL is synchronized. This means that over the observation period M,
If the LPF output exceeds 0.25, it means that it can be determined that the state is asynchronous. The value of M is, for example, 50. It can be easily confirmed that M = 50 sufficiently satisfies the above expression.

FIGS. 9 and 10 show simulation results of the phase pull-in characteristic of the PLL according to the present invention. Each figure shows a time transition of the PLL phase control error when the response speed (rise time) of the PLL is 0.17 ms and 2 ms, and the upper side shows the characteristics of the conventional system and the lower side shows the characteristics of the system of the present invention. I have. Here, Δf = 5 kHz is assumed as the frequency offset. PLL
The phase control error (unit: rad) is the VCO in FIG.
The difference between the output and its theoretical value. Data rate is 32k
One bps and one frame (= 960 bits) corresponds to 30 ms. It is assumed that data is received at the time 0 from the beginning (unique word) of the frame.

As is clear from the figure, in the conventional method, P
It can be seen that a large phase change occurs at the time of re-receiving the unique word after the LL pull-in (the 961th bit and thereafter), which significantly degrades the characteristics of the PLL. On the other hand, in the method of the present invention, even if a unique word is received at the same time, it is not affected by the phase fluctuation, and there is no malfunction of the PLL. This is because abnormally large phase fluctuations are removed by the synchronization state monitoring means and the phase difference determination means.

In the conventional method, the effect of the phase fluctuation is reduced by reducing the response speed of the PLL. However, as can be seen from FIG.
It is not possible to completely eliminate the effects of phase fluctuations caused by unique words. On the other hand, according to the method of the present invention, the PLL operates normally without being affected by the phase fluctuation even when the unique word arrives.

In the above description, the quasi-synchronous detection demodulation, that is, the method of compensating for the deviation by the baseband processing of the receiving unit when the carrier frequency and the phase between transmission and reception are slightly different, is premised. The present invention is also applicable to synchronous detection demodulation, that is, a method of compensating a carrier frequency and a phase shift between transmission and reception in a carrier band.

[0054]

As is apparent from the above description, according to the present invention, the base station only needs to insert a unique word into the pilot channel, and does not need to provide a synchronization channel. Can be improved. Further, in the mobile station, since the receiving section performs frame synchronization using a pilot channel output with higher transmission power (usually about 10 dB or more) than the traffic channel, higher S / S than before is achieved.
N can demodulate the data.

Further, by providing the quasi-synchronous detection and demodulation device with a synchronization state monitoring means, a switching control means, and a phase error determination means, a synchronous / asynchronous state is automatically observed and an appropriate position according to the state is provided. It is possible to switch to the phase difference correction processing. Further, even if the pilot signal includes data (unique word) whose phase changes irregularly, it is possible to eliminate the influence of a large phase fluctuation caused by the data and prevent malfunction of the PLL.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a CDMA mobile communication system.

FIG. 2 is a diagram showing a configuration of a base station transmitting unit and a mobile station receiving unit in a conventional CDMA modem.

FIG. 3 is a diagram showing an example of a frame configuration of a pilot signal. ,

FIG. 4 is a diagram showing an example of signal point arrangement and reception points by QPSK modulation.

FIG. 5 is a diagram showing a configuration of a base station transmitting unit and a mobile station receiving unit in the CDMA mobile communication system of the present invention.

FIG. 6 is a diagram showing a configuration of a quasi-synchronous detection and demodulation device according to the present invention.

FIG. 7 is a view for explaining phase difference correction for preventing reverse control of the phase by the PLL.

FIG. 8 is an explanatory diagram of a synchronization state monitoring unit.

FIG. 9 is a diagram illustrating an example of a simulation result of a PLL pull-in characteristic in the quasi-synchronous detection and demodulation device.

FIG. 10 is a diagram illustrating another example of the simulation result of the PLL pull-in characteristic in the quasi-synchronous detection and demodulation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Phase correction part, 2 ... Amplitude normalization part, 3 ... Phase difference calculation part, 4 ... Reference signal, 5 ... Phase difference correction 1, 51 ... Phase difference correction 2, 6 ... Loop filter, 7 ... VCO, 8 ... Sine wave generator, 9: data demodulator, 10: synchronization state monitor, 11
... Switching control unit, 12 ... Phase difference determination unit, 11-13 ... Base station, 14-16 ... Cell, 17 ... Radio channel control station, 21 ...
Pilot data generation unit, 22: phase modulation unit, 23: spread spectrum unit, 24: multiplexing unit, 25: synchronization channel data generation unit, 26: unique word insertion unit, 27: mobile station data generation unit, 28: carrier Modulation unit, 29: base station antenna, 30: mobile station antenna, 31: carrier demodulation unit, 32: spectrum despreading unit, 33, 33a: quasi-synchronous detection demodulation unit, 34: frame synchronization unit, 81: multiplier, 82 ... Adder, 83 ... Delay element, 101-106 ...
Mobile station.

Continuation of the front page (56) References JP-A-3-289831 (JP, A) US Patent 5,103,459 (US, A) Salmasi, A .; and Gio housen K. S. "On the System Design Aspects of Code Division Multiple Accesses (CDMA) Applied to Digital Cellular Communications and International Communications Technology." Gateway to the Future Technology in Motion. , 41st IEEE, pages 57-62 (58) Fields studied (Int. Cl. ⁷ , DB name) H04B ^7/ 24-7/26 102 H04Q 7/00-7/38 H04J 13/00

Claims (7)

(57) [Claims] 1. A base station periodically inserts a frame sync signal to the pilot signal, and sends the air to the pilot signal and the signal of the traffic channel addressed to each mobile station spread spectrum respectively, each mobile station but, CDMA mobile communication system, characterized in that extracting the frame synchronization signal from the pilot signal <br/>, demodulates the data based on the frame sync signal from the received signal of the traffic channel. 2. A means for generating a pilot signal into which a unique word is inserted for each frame period, means for phase-modulating the pilot signal, and synchronizing data addressed to a plurality of mobile stations with the phase-modulated pilot signal. Means for performing phase modulation, means for spectrum-spreading the phase-modulated pilot signal and data, means for multiplexing the plurality of spectrum-spread signals, and carrier-modulating the multiplexed output for transmission. A base station apparatus for a CDMA mobile communication system, comprising: a transmission unit comprising: 3. A means for carrier demodulating a received spread spectrum signal, a means for spectrum despreading the demodulated output and outputting as a pilot signal and a data signal, and a means for despreading the pilot signal and the data signal, respectively. The means for correcting the phase and the frame synchronization signal
The frame for the inserted pilot signal after the phase correction
Means for performing frame synchronization and quasi-coherent detection by chromatography beam synchronization signal, the mobile station of the CDMA mobile communication system comprising: a receiver comprising a means for demodulating in synchronization with the data after the phase correction to the pilot signal . 4. The receiving unit according to claim 1, wherein the frame synchronization signal is inserted.
The said frame same from the pilot signal after the phase correction
Means for detecting the start of a frame based on the phase signal, means for demodulating the data signal after the phase correction at the output timing of the signal for detecting the start of the frame, and means for normalizing the amplitude of the pilot output after the phase correction Means for calculating a phase difference between the normalized pilot signal and the reference signal; means for monitoring a phase synchronization state based on the magnitude of the phase difference; and signal switching control based on the synchronization state or the asynchronous state. Means for correcting the phase difference according to the output of the switching control means, a loop filter for removing a noise component of the corrected phase difference, means for integrating the output of the loop filter, and the integration result 4. A means for generating a sine wave having a phase corresponding to the phase of the pilot signal, wherein the phase correction means rotationally corrects the phase of the pilot signal using the sine wave. The mobile station of the CDMA mobile communication system. 5. A periodically inserts a frame sync signal to the pilot signal, the base station apparatus for transmitting in the air said pilot signal and the signal of the traffic channel addressed to each mobile station by spread spectrum, respectively. 6. The base station apparatus according to claim 5, wherein said frame synchronization signal is inserted at the beginning of a frame. 7. A mobile station extracting a frame synchronization signal from a pilot signal into which a frame synchronization signal is periodically inserted, and demodulating data from a received signal of a traffic channel based on the frame synchronization signal. .