JPH10126331A - Mobile communication system and its equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve propagation path estimate accuracy in the interpolation pilot system for the direct sequence-code division multiple access (DS-CDMA) system, with respect to the mobile communication system and its equipment. SOLUTION: In the mobile communication system in which a mobile equipment MS estimates a propagation path, based on a known pilot signal PS interpolated to an outgoing frame of a communication channel TCH by a base station BS, a BS1 transmits each outgoing frame to which the PS is interpolated, while the phase of each frame is deviated for each TCH and MS1/MS3 sample in time series interpolated PS1, PS3 to each TCH to use the result for distortion compensation demodulation of the data signal. The base station sends each outgoing transmission frame in phase and spreads each PS by using only a code CC in common to all channels and spreads data parts by using only codes C1-Cn specific to each channel. The MS1/MS3 use the common PS whose signal power (reception Eb/Io, that is, S/N of the inverse spread signal) is increased to conduct distortion compensation demodulation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system and a mobile communication system, and more particularly, to a base station apparatus and a mobile terminal apparatus in which a DS-CDMA (Direct Sequence Code Divi) is used.
The present invention relates to a mobile communication system and a mobile communication system in which a mobile terminal device estimates signal propagation path characteristics based on a known pilot signal interpolated in a downlink frame of a communication channel by a base station device connected by a sion multiple access method.

2. Description of the Related Art In recent years, in mobile communication systems such as car phones and mobile phones, a conventional TDMA (Time Division Multipl
e Access) method, instead of the DS-CDMA method (hereinafter referred to as the “DS-CDMA method”), which is superior in fading measures and can accommodate more subscribers
Research and development for practical use of a mobile communication system based on a CDMA system have been actively conducted. The present invention particularly relates to improving the accuracy of signal propagation path estimation using an interpolation pilot scheme.

[0003]

2. Description of the Related Art FIGS. 19 to 22 are diagrams (1) to (4) for explaining a conventional technique. Hereinafter, the background art will be described. C
In a DMA cellular system, it has been proposed to use a combination of a short spreading code and a long spreading code so that an infinite number of spreading codes can be generated in order to avoid the trouble of arranging and rearranging spreading codes. However, in addition to using the same frequency for each cell, it is necessary to perform initial synchronization to capture a timing error between a spread code of a received signal and a replica of the spread code within a half chip cycle during cell search or handover. The time required for this synchronization is problematic.

In this respect, the conventional two-stage high-speed initial synchronization method of long code in the asynchronous cellular system between DS-CDMA base stations (IEICE Technical Report of IEICE.
19, RCS96-12 (1996-05), P27-P32) are known. This method first performs a first-stage synchronization with a short code common to each cell (base station), and uses this information to perform a second-stage synchronization of a long code different for each cell. It is. The outline will be described below.

FIG. 19A shows a partial configuration of a base station transmission system, and FIG. 19B shows a partial configuration of a mobile station synchronization system. FIG. 20 shows a timing chart of the two-stage high-speed initial synchronization. In the base station transmission system of FIG. 19A, SCG is a short code generator, LCG is a long code generator, MIX is a mixer (signal multiplying circuit), and +
Is a signal multiplexing circuit, and TCONT is a timing control unit.

The control channel of the base station BS1 is spread with a short code SC common to each cell, while the communication channels 1 to n are short codes S1 to Sn unique to each channel.
Is spread by. Each spread signal is synthesized by a multiplexing circuit and further double-spread with a long code L1 unique to BS1.
However, one symbol of this control channel is preliminarily spread by a long code / L1 which is a complex conjugate of the I and Q components of the long code L1, thereby masking (cancelling) the spreading by the subsequent L1. ing. Other BS
2, BS3 and the like. Accordingly, for the control channel, the one symbol spread with the short code SC common to each cell is obtained.

In the mobile station synchronization system shown in FIG.
W is a reception signal changeover switch, MF is a matched filter (Mat
MEM, MEM is a memory, MAXSEL is a correlation output maximum value selector, and CMP is a comparator. Mobile device MS
The received signal of No. 1 is first input to the long code synchronization timing detector, where the matched filter MF detects the correlation with the short code SC. The correlation is amplitude squared detected and stored in the MEM. In this case, in order to capture the control channel with the highest average received power in the cellular mobile device, correlation detection of multiple frames is performed, and the effects of inter-channel interference and fading in the mobile device environment are averaged. I do. Then, the timing at which the maximum correlation square value (the maximum correlation peak value) is obtained is defined as the long code synchronization timing T.

After detecting the long code synchronization timing T, the received signal is input to a long code identification unit.
Here, the code SC + L1 synchronized with the long code synchronization timing T is not used as the replica code, the correlation with the data portion is integrated for one symbol period by the sliding correlator, squared detection is performed, and the sum of the M symbol sections thus obtained is obtained. To M
The threshold is determined based on the threshold TH determined according to the maximum correlation peak value of AXSEL. Correlation value is threshold T
If it does not exceed H, the long code is changed and the above operation is repeated. If the correlation value exceeds the threshold value TH, the cell search (initial synchronization) is completed via the confirmation mode.

The operation of the initial synchronization will be specifically described with reference to the timing chart of FIG. MS1 has BS1 to BS
Same frequency from 3, long code period 10ms, BS
Each control channel signal that is asynchronous between is simultaneously received. M
In the code timing detection phase of S1 (the section indicated by the dotted line in the figure), the maximum correlation is obtained between the timings of the one symbol of the BS3. Therefore, the time T from the reference timing (dotted line) of the MS1 is the long code synchronization timing T
Becomes

[0010] In the subsequent long code identification phase, in the case of the initial cell search, the long code group of the neighboring cell notified from BS1 is selected from among the long code group defined by the system or in the case of the neighboring cell search at the time of handover. From among them, replica codes of SC + Li (i = 1, 2,..., M) are sequentially generated, and correlation detection is performed. In this example, SC +
Identification of BS3 is obtained by detecting the correlation of L3. Thus, it is reported that the 90% detection time of cell search by this method has been reduced to about 350 ms to 850 ms under various mobile environment.

In a CDMA cellular system, pilot symbols are used to reduce the required E _b / I _o (ratio of signal power to interference power and background noise power density per information bit) and increase cell capacity. Synchronous detection,
It has also been proposed to estimate and compensate for fading distortion. The propagation path estimation method using the pilot signal includes an extrapolation pilot method (US Pat. No. 5,166,955).
1) and interpolation pilot method ("16Q for land mobile communication"
AM Fading Compensation Method ”IEICE Transactions on Electronics, B-II V _OL J72-B-II N _O. 1PP.7-15 January 1989)
Etc. are known.

FIG. 21 shows an outline of the extrapolation pilot method. The figure shows a downlink from the base station to the mobile station. In the extrapolation pilot method, a communication channel (control channel CCH, communication channels TCHI1 to TCH1) is used.
A channel PCH dedicated to pilot signals is provided separately from n), and transmission of pilot signals is exclusively performed. The mobile station can always directly perform channel estimation and compensation using this pilot signal. However, there is a problem that a pilot signal channel PCH is required for each frequency, and the channel use efficiency of the system is reduced.

FIG. 22 shows an outline of the interpolation pilot method. In this method, fading distortion is estimated from known pilot symbols periodically inserted, and the time series is interpolated to estimate fading distortion in all information symbols to perform distortion compensation. FIG. 22A shows the format of the interpolation pilot system.

One transmission path measurement pilot symbol PS is inserted for every N-1 information symbols IS. As the pilot symbol PS, points A to D having the maximum amplitude are suitable as shown in the insertion diagram (a). Here, point A (3 + j3) is used. FIG. 22B shows the configuration of the fading distortion estimation / compensation unit of the receiver. Although the illustration of the preceding stage of the receiving unit is omitted, the received signal is band-limited by the BPF,
After the received signal level is properly set by GC and the offset frequency is roughly adjusted by AFC, quasi-synchronous detection is performed by the local oscillation signal. Further, the band of the detected baseband signal is limited by the LPF, and out-of-band noise and adjacent channel interference are suppressed, and then input to the fading distortion estimation / compensation unit.

The input received complex baseband signal u (t)
U (t) = c (t) z (t) + n (t) where c (t): fading distortion signal z (t): equivalent to transmission complex baseband signal n (t): white Gaussian noise Can be expressed. In order to remove the distortion due to c (t) from u (t), an estimated value C (t) of c (t) is obtained from the received signal u (t), and further, the optimal gain, h (t) = 1 / C (t) may be calculated and multiplied by u (t).

In the figure, a frame synchronizing unit detects a frame timing (period T) from an input baseband signal u (t).
_F ), and the clock synchronization section reproduces the clock timing (period T _S ) from u (t). Frame length is N
When the timing of each _{symbol, t = kT F + (m} / N) T F (k = 0,1,2, ..., m = 0,1,2, ..., N-
1). The timing of the pilot symbols PS are the case of m = 0, _{i.e., t = kT F (k =} 0,1,2, ...) become.

[0017] t = kT reception in _F complex baseband signal u (k) is expressed as u (k) = c (k ) (3 + j3) + n (k). Here, assuming that the estimated value C (k) of c (k) is C (k) = u (k) / (3 + j3), C (k) = c (k) + n (k) / (3 + j3) can get. Further, by interpolating the time series of C (k), it is possible to estimate fading distortion in each information symbol. An example of interpolation using the second-order Gaussian formula will be described below.

In the fading distortion estimator, t =
(K-1) T_F, T = kT_F, T = (k + 1) T_FGet in
The estimated values of the obtained fading distortions are respectively denoted by C (k−
1), C (k), C (k + 1), a certain symbol
Time t = kT_F+ (M / N) T _FFading in
The variation C (k + (m / N)) is C (k + (m / N)) = Q_-1(M / N) C (k-1) +
Q₀(M / N) C (k) + Q₁(M / N) C (k + 1) where Q_-1(M / N) = ｛(m / N)^Two− (M / N)｝
/ 2 Q₀(M / N) = 1− (m / N)^Two Q₁(M / N) = ｛(m / N)^Two+ (M / N)｝ / 2.

In the fading distortion compensating section, the optimum gain = 1 / C (k + (m / N)) is further obtained, and this is multiplied with the input signal delayed by T _F sec in the delay section to obtain the fading distortion. , A complex output baseband signal Z (k + (m / N)) is obtained. It should be noted that, if the first-order interpolation is used instead of the second-order interpolation, the interval between pilot symbols is estimated by a straight line. If the interpolation is of the 0th order, the estimated value of the pilot symbol is held for one frame.

Accordingly, a dedicated pilot signal channel PCH as in the extrapolation pilot method is not required, and the channel use efficiency of the system is improved.

[0021]

However, according to the interpolation pilot method described above, there is a disadvantage that a propagation path estimation error in each information symbol becomes large due to an interpolation error. Also, when the number of users (mobile devices) that communicate simultaneously increases,
The interpolation pilot signal itself is degraded in quality (graceful degr
Therefore, the accuracy of the channel estimation value of the pilot symbol, which is the basis of the interpolation, cannot be obtained.

It is an object of the present invention to provide a mobile communication system and an apparatus thereof with improved channel estimation accuracy in an interpolation pilot system.

[0023]

The above-mentioned problem is solved, for example, by referring to FIG.
The problem is solved by the configuration of (A). That is, the mobile communication system of the present invention (1) includes a base station apparatus BS and a mobile terminal apparatus M
S is connected by the DS-CDMA method, and the mobile terminal apparatus MS estimates signal propagation path characteristics based on a known pilot signal PS inserted by the base station apparatus BS in a downlink frame of the communication channel TCH. In the communication system, the base station apparatus BS1 transmits a common pilot signal P
Each downlink frame obtained by interpolating S1 and PS3 in a common format is at least an interpolation pilot signal PS for each of the communication channels TCH1 and TCH3 used by one or more mobile terminal devices MS1 and MS3. The mobile terminal MS1 / MS1 /
MS3 is an interpolation pilot signal PS of each downlink frame.
1, for estimating signal propagation path characteristics based on the time series of PS3.

Therefore, according to the present invention (1), each mobile terminal device MS1 / MS3 has its own interpolated pilot signal PS.
Not only 1 / PS3 but also other busy channels TCH3 / T
The interpolated pilot signal PS3 / PS1 of CH1 can also be used in time series (without duplication) for the purpose of channel estimation. Therefore,
It has excellent followability to fading fluctuations and the like, and the accuracy (quality) of channel estimation is significantly improved. Moreover, the effect of the accuracy improvement increases with an increase in the number of connections of the mobile terminal device MS,
If all communication channels TCH1 to TH of the base station device BS1
n is in use, a dedicated pilot signal channel P
Without providing a CH, a fading distortion compensation effect similar to that of the conventional extrapolation pilot method and, consequently, an effect of improving synchronization in synchronous detection can be obtained.

In the illustrated example, the communication channel TCH2
Is not in use. In this case, the base station apparatus BS1 transmits frame transmission of the communicating channel TCH3 to the communication channel TC.
You may transmit by the phase of H2. The above problem is solved by, for example, the structure of FIG. That is, in the mobile communication system according to the present invention (2), in the mobile communication system based on the above-described premise, the base station apparatus BS1 has each downlink frame in which one or more common pilot signals PS1 and PS3 are interpolated in a common format. Is transmitted in the same phase to each of the communication channels TCH1 and TCH3 used by one or more mobile terminal devices MS1 and MS3, and the interpolated pilot signals PS1 and PS3 of each of the downlink frames are transmitted to all the communication stations. Channels TCH1 to TCHn are spread by a common code CC, and mobile terminal devices MS1 / MS3 transmit interpolation pilot signals PS1, PS1 of the spread downstream frames.
PS3 is despread with a code CC common to all the communication channels.

According to the present invention (2), the base station apparatus BS1
Spreads each of the interpolation pilot signals PS1 and PS3 with a common code CC for all communication channels TCH1 to TCHn, so that the code multiplex transmission power of the interpolation pilot signals PS1 and PS3 is increased by increasing the number of mobile stations during a call. It will be strengthened accordingly. On the other hand, the mobile stations MS1 / MS3 despread the received pilot signals PS1 and PS3 with the code CC common to all the communication channels, so that the SN ratio of the despread signal (that is, E _b / I _o ). Is improved as the number of mobile devices during a call increases. Therefore, even if the number of users (mobile devices) communicating at the same time increases, the graceful degradation of the interpolation pilot signal itself is reduced, and thus the propagation path estimation of the pilot signal PS as a basis for interpolation and the like is performed. High accuracy is obtained for the values.

Preferably, in the present invention (3), in the present invention (2), as shown in FIG. 8, for example, the base station apparatus transmits the interpolated pilot signal PS of each downlink frame to all communication channels of its own station. Are spread only with the common long code L1, and the other signals in each frame are double-spread with the long code L1 and the short codes S1 to Sn unique to the communication channels TCH1 to TCHn.

Therefore, the same effect as that of the present invention (2) can be obtained. In addition, in the CDMA cellular system, the long code L1 is normally used for color-coding each base station device (cell). Therefore, it is not necessary to assign a special code to realize this function from a finite code group. The existing long code L1 can be utilized. In addition, matching with the spreading method of the data portion is achieved, so that the configurations of the base station apparatus and the mobile terminal apparatus are simplified.

Preferably, in the present invention (4), in the above-mentioned present invention (2), as shown in FIG. 10, for example, the base station apparatus transmits the interpolated pilot signal PS of each downlink frame to all of its own stations. Only the first short code SC common to the channels is spread, and the other intra-frame signals are spread by the long code L1 common to all communication channels of the own station and the second codes unique to the communication channels TCH1 to TCHn. Double-spread with short codes S1 to Sn.

Therefore, the same effects as those of the present invention (2) can be obtained. Moreover, since the interpolation pilot signal PS is spread only by the first short code SC common to all the communication channels TCH1 to TCHn of the base station device, the signal level of the spread code replica per symbol is fixed to any one. Don't worry. That is, this interpolated pilot signal PS is sufficiently spread in spectrum and despread in a mobile terminal device with high correlation. In addition, matching with the spreading method of the data portion is achieved, so that the configurations of the base station apparatus and the mobile terminal apparatus are simplified.

Preferably, in the present invention (5), in the above-mentioned present invention (2), as shown in FIG. 12, for example, the base station apparatus transmits the interpolated pilot signal PS of each downlink frame to all of its own stations. The channel is double-spread with a first short code SC common to the channels and a long code L1 common to all communication channels of the own station, and other signals in each frame are transmitted to the long code L1 and each communication channel TCH1.
To TCHn are double-spread with the second short codes S1 to Sn unique to TCHn.

Therefore, the same effect as that of the present invention (2) can be obtained. Moreover, the interpolation pilot signal PS is the first short code SC common to all communication channels of the base station apparatus.
Also, since the signal is double-spread with the long code L1, the inter-cell interference of the interpolated pilot signal PS is sufficiently suppressed. Also, it is consistent with the diffusion method of the data part,
Therefore, the configurations of the base station device and the mobile terminal device are simplified.

Preferably, in the present invention (6), in the above-mentioned present invention (3), as shown in FIG. 14, for example, as shown in FIG. A control channel for transmitting a downlink frame having a substantially common format in the same phase as the communication channel, wherein at least one leading symbol of the downlink frame of the control channel is spread only by a short code S0 common to the system, and Of the communication channel TCH of the own station.
And the other intraframe signals are double-spread with a short code S0 common to the system and a long code L1 common to all communication channels of the own station.

Therefore, the same effects as those of the present invention (2) can be obtained. In addition, in this example, even in the control channel CCH which is always used, the remaining interpolated pilot signals PS are spread only by the common long code L1 to all the communication channels TCH of the own station. Even if the number of mobile units during communication is one, each interpolation pilot signal P
There is an effect that the reception SN of S is improved.

Since at least one leading symbol of the downlink frame of the control channel is spread only by the short code S0 common to the system (each cell), the leading one symbol is turned on by the mobile terminal device in the cell. Can be used as a symbol for synchronization acquisition at the time of handover or handover. Also preferably, in the present invention (7), in the above-mentioned present invention (5), for example, as shown in FIG. 17, the base station apparatus has a format common or substantially common to its own communication channel with respect to the interpolation pilot signal PS. And a control channel CCH for transmitting a downlink frame having the same phase as the communication channel, and a first short code SC common to all communication channels of the own station in the present invention (5). Short code S0 of 1
At least one leading symbol of the downlink frame of the control channel is spread only by the first short code S0 (preferably one symbol length), and the other intra-frame signals are transmitted to all communication channels of the own station. Double spreading is performed with a common long code L1 and the first short code S0.

Therefore, the same effect as that of the present invention (6) can be obtained. In addition, since each interpolation pilot signal PS is double-spread with the code S0 + L1, any of the interpolation pilot signals PS is sufficiently spectrum-spread by using the short code S0 together. Also preferably, in the present invention (8), in the above inventions (2) to (5), the base station apparatus changes the transmission power of the interpolated pilot signal PS of each communicating channel according to an increase in the number of communicating channels. And make it smaller.

On the side of the base station apparatus, for example, the transmission power of each interpolated pilot signal PS is 1 / (the number of mobile terminal apparatuses during a call).
, The signal power of the interpolated pilot signal PS despread on the mobile terminal apparatus side becomes the same as the signal power obtained by despreading the data part of the channel during communication. Therefore, signal processing on the mobile terminal device side is facilitated. Also, in this case, the base station device can reduce interference given to another base station device (cell) by lowering the transmission power of the interpolated pilot signal PS.

In the mobile terminal of the present invention (9), the base station and the mobile terminal are connected by a DS-CDMA system, and the base station has a known pilot inserted into a downlink frame of a communication channel. In the mobile terminal device of the mobile communication system in which the mobile terminal device estimates a signal propagation path characteristic based on a signal, the base station device is common to each communicating channel used by one or more mobile terminal devices. A distortion compensation unit for despreading and demodulating a common interpolation pilot signal spread in phase with the code to obtain a distortion compensation coefficient of a signal propagation path,
A data demodulation unit that despreads the data signal, which the base station apparatus has spread with a unique code for a specific communication channel, with the unique code, and demodulates the data signal using the distortion compensation coefficient. It is.

Therefore, such a distortion compensating section is provided with the SN
It is possible to determine a highly accurate distortion compensation coefficient based on the interpolated pilot signal with improved (ie, E _b / I _O ).

[0040]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the same reference numerals indicate the same or corresponding parts throughout the drawings. FIGS. 2 to 4 are diagrams (1) to (3) for explaining the mobile communication system according to the first embodiment, in which the base station shifts the transmission phase of the PS interpolation frame for each channel, and A case where interpolation PS of a channel during communication is used in time series is shown.

FIG. 2 shows a partial configuration of the base station transmission system. The base station has a maximum of n communication channels TCH1 to TCHn. Although there is another control channel CCH (not shown), attention is focused on the communication channel here. In TCH1, the frame buffer FB1 stores the interpolation pilot symbols PS (for example, each one symbol) and the data symbols IS for one transmission frame in a predetermined (FIG. 3) format. The frame information of FB1 is a frame pulse signal FP1.
The signal is read out in synchronization with (corresponding to the frame pulse signal FP of the base station) and primary-modulated by the modulation unit MOD such as QPSK. On the other hand, the short code generation unit SCG1 is triggered in synchronization with the FP1, and generates a spread code replica (PN signal or the like) corresponding to the unique short code S1 set in advance for TCH1 with one symbol length of information as a period. It has occurred repeatedly. The mixer MIX1 performs spectrum spreading (secondary modulation) on the primary modulation signal from the MOD using a spreading code replica of the short code S1. The spread signal is multiplexed with another spread signal by a signal multiplexing circuit (addition circuit) + and transmitted to the downlink for the mobile station. Other T
The same applies to CH2 to TCHn.

However, in this base station, the transmission phases FP1 to FPn of each TCH frame are determined by the timing control unit TCON.
The timing is shifted by the number of interpolation PSs (2 PS in this example) by the timing control of T. That is, in TCONT, the counter CTR synchronizes with the frame pulse signal FP of the base station (control channel) and outputs the symbol clock signal S
The counting cycle for one transmission frame is repeated by CK. The timing decoder DEC generates transmission timing signals FP1 to FPn for each of TCH1 to TCHn based on the count output Q of the CTR.

FIG. 3 shows a timing chart of the downlink. One frame of each TCH includes m slots of a predetermined length, and one PS is interpolated before and after each slot. The rest are data symbols. It should be noted that this slot may be considered to have a meaning that indicates the PS insertion interval. The signal of TCH1 (FB1) is read out in synchronization with FP1, and is continuously transmitted for one frame. Also TC
The H2 signal is read out in synchronization with FP2 which is delayed by 2 PS from FP1, and is transmitted continuously for one frame. Thereafter, the signal of TCHn is given by 2 × (n
-1) The data is read out in synchronization with FPn delayed by PS and transmitted continuously for one frame. And in this example, TC
When the first PS of Hn is transmitted, the next symbol timing is the second PS of TCH1 (the rear end of slot 1).
Are transmitted. Therefore, if all the TCs of the base station
When H1 to TCHn are communicating, PS exists in any TCH at any symbol timing of one frame.

However, this base station performs frame transmission (frame multiplexing) only on the communication channel in use, and does not perform frame transmission (frame multiplexing) on the communication channel not in use. Therefore, the use state of each TCH dynamically changes in response to a call connection / disconnection request of a large number of mobile stations. For example, at one time, TCH1 to TCH5 are used at the same time, and at another time, only TCH3 and TCHn are used. Used at the same time.

FIG. 4A shows a partial configuration of a mobile terminal receiving system. Here, a despreading / demodulating unit and a distortion compensating unit are shown. The synchronization system of the mobile device is shown in FIG.
The same one as the synchronous system described in 9 (B) can be adopted. Also, the description will be made assuming that this mobile device is connected to TCH1. In the despreading / demodulation unit, the short code generation unit SCGa is triggered in synchronization with FP1, and repeatedly generates a despread code replica corresponding to the short code S1 specified in advance by the base station at a symbol period. FP1
Has already been obtained at the time of connection to the control channel (or TCH1) of the base station by a not-shown synchronization system {similar to that described in FIG. 19B}. The input code multiplex reception signal MSRX is first converted into S by the mixer MIXa.
Despreading by CGa despreading code replica (secondary demodulation)
Is done. Various cases are conceivable for the delay amount of the delay circuit DL, which will be described later. The mixer MIXb multiplies the input secondary demodulated signal by a compensation coefficient CS from a distortion compensator described later. The distortion-compensated secondary demodulated signal is primarily demodulated by a primary demodulation unit DEM using QPSK or the like, and becomes TCH1 reception data.

In the distortion compensator, SCGA is FP
1, each short code Si (i = 1 to 1) cyclically shifted by a code shift register CSR described later.
n) A corresponding despread code replica is sequentially generated in each symbol period. The code multiplex reception signal MSRX is output from the mixer MI.
In XA, each short code Si is sequentially despread by a despread code replica (secondary demodulation), and similarly primary demodulated by a primary demodulation unit DEM using QPSK or the like.

The coefficient determination unit estimates distortion due to fading or the like from each received pilot symbol PS in the same manner as described with reference to FIG. 22B, for example, and determines an optimal distortion compensation coefficient CS. This distortion compensation coefficient CS is, for example, as shown in the inset (a), a deviation of the reception complex baseband signal RXP from the transmission complex baseband signal TXP (in this example, the known code point A (1 + j1) of the transmission PS). Compensation may be performed on the rectangular coordinates I and Q, or the displacement may be calculated using the polar coordinates CS-r and C as shown in FIG.
The compensation may be performed by decomposing the component into S-θ components. However,
The distortion compensation coefficient CS in the latter case is added to the DEM.

The code shift register CSR stores short code information of up to n communication channels (two per communication channel) notified in advance by broadcast information or the like from the base station, and synchronizes them with the FP1. In addition, a cyclic shift is performed by the symbol clock signal SCK. Preferably, when each of the short codes S1 to Sn used in the base station is unique (fixed) to each of the communication channels TCH1 to TCHn, regardless of whether or not each base station uses each TCH, the mobile station side uses all TCHs. Are stored in advance. Such storage may be performed once based on broadcast information or the like when the mobile station connects to the base station.

CSR when mobile unit is connected to TCH1
Are stored in a phase pattern synchronized with FP1. That is, as shown in FIG. 4A, the CSR stores the phase pattern of “S1, S2, S2,..., Sn, Sn, S1”. Incidentally, when the mobile station is connected to TCH2, the storage of S1 to Sn in the CSR is performed in a phase pattern synchronized with FP2. That is, "S2, S3,
S3,..., Sn, Sn, S1, S1, S2 ". This phase pattern corresponds to the TC shown in FIG.
It can be easily understood from the phase relationship of H2. Further, this phase pattern can be easily obtained by simply cyclically shifting the phase pattern in the case where the mobile station is connected to TCH1 by 2SCK in advance in the direction of the arrow.

Therefore, in general, any TCHi (i = 1 to 1)
Even when connecting to n), the FP1
All short codes S1 to Sn with a phase pattern synchronized with
Are temporarily stored in the CSR as they are, and then these are cyclically shifted by 2 × (communication channel number −1) times according to the information (number) of the communication channel to which the own station is connected. Can be easily obtained.

The timing shift register TSR stores timing information for n communication channels (two per channel) previously notified by broadcast information or the like from the base station (bit information 1/0 for use / non-use for all TCHs). ) Are stored, and these are cyclically shifted in synchronization with the FP1 and by the symbol clock signal SCK. This bit information 1
The contents of / 0 change dynamically (in frame units) according to the state of call connection / disconnection of each mobile station. The concept of the phase pattern of the bit information may be the same as that for the code information.

FIG. 4B shows the timing shift register T
An example of an SR storage pattern is shown. Here, a case is shown where one slot is composed of 12 symbols. TCH
This corresponds to six TCH1 to TCH6. When only TCH1 is being used (only the own station is connected), the storage bit pattern of TSR is “1000,0000,0001” of TSR (1) in the figure. In this case, the base station transmits a frame using only TCH1 (frame multiplexing).
And the other TCHs 2 to n do not perform frame transmission (frame multiplexing). Therefore, the PS available in the system (cell) is the PS interpolated before and after each slot of TCH1.
Only (1) and (12).

In the mobile station, at the timing of FP1, the bit of the TSR = 1 and the SGC of the distortion compensation unit
The A, DEM, and coefficient determination units are simultaneously activated. Thus, despreading of the received PS (1) by the short code S1, first-order demodulation, and determination of the distortion compensation coefficient CS (1) are performed. In this case, the delay amount of the delay circuit DL is, for example, 0 symbols. That is, the DL is deleted. As a result, the next first data symbol I
At the timing when S (2) is demodulated, distortion compensation is performed using the distortion compensation coefficient CS (1) determined immediately before. Thereby, data symbol IS (2) can be properly demodulated.

On the other hand, the first data symbol IS
At the timing when (2) is demodulated, the contents of CSR and TSR are both cyclically shifted by SCK by one, and C
The output of SR = S2 and the output of TSR = 0. As a result, the SGCA, DEM and the coefficient determining unit of the distortion compensating unit are simultaneously deenergized, and the coefficient determining unit holds the distortion compensation coefficient CS (1) obtained immediately before. Hereinafter, up to the tenth data symbol IS (11) is demodulated using the held distortion compensation coefficient CS (1). At the next twelfth timing, the content of CSR = S1, the content of TSR = It becomes 1. Thus, despreading of the received PS (12) by the short code S1, first-order demodulation, and redetermination of the distortion compensation coefficient CS (12) are performed.

Next, at the same time as the above-mentioned TCH1,
When H3 and H6 are being used, the storage bit pattern of TSR is “1001, 1000, 011” of TSR (3) in the figure.
1 ". In this case, the base station performs frame transmission (frame multiplexing) only on TCHs 1, 3, and 6, and transmits the other TCHs.
Frame transmission (frame multiplexing) is not performed for 2, 4, and 5. Therefore, the PS available in the system (cell)
Is each P interpolated before and after each slot of TCH1,3,6
S (1), (4), (5), (10) to (12).

In the mobile station, the operation from the timing of FP1 until the third data symbol IS (4) is demodulated may be the same as described above. However, the timing at which the third data symbol IS (4) is received is determined by another TC.
PS (4) has been transmitted to H3. In the distortion compensating unit in this case, SGCA, D
The EM and the coefficient determiner are simultaneously energized again. Thus, despreading of the received PS (4) by the short code S3, first-order demodulation, and redetermination of the distortion compensation coefficient CS (4) are performed. As a result, the next data symbol I
At the timing when S (5) is demodulated, distortion compensation is performed using the distortion compensation coefficient CS (4) determined immediately before. As a result, the data symbol IS (5) can be properly demodulated. The next data symbol IS
At the timing when (6) is demodulated, the distortion compensation coefficient CS (5) ｛or CS (4) and CS (4) determined immediately before are demodulated.
(5) The distortion is compensated by the average value｝ or the like. Thereafter, the CS (5) is held until the next PS analysis result is obtained. The same applies hereinafter. The above description of this mobile device is the same for other mobile devices, except that the initial storage patterns of CSR and TSR are different.

As described above, according to the first embodiment, the mobile station can use not only its own station but also the PS portions of other TCHs (mobile stations) in a time series without duplication. Therefore, the accuracy (quality) of channel estimation is significantly improved. The effect of this accuracy improvement increases with an increase in the number of mobile terminals connected, and if all TCHs of the base station are in use, the fading distortion compensation effect similar to that of the conventional extrapolation pilot method and, consequently, the synchronous detection. The effect of improving synchronization is obtained.

In the first embodiment, the case where distortion compensation of the next data symbol IS is performed based on the immediately preceding PS analysis result (or average value) is described. However, the present invention is not limited to this. For example, in the same manner as described with reference to FIG. 22, the time series of the distortion compensation coefficient CS may be interpolated based on a plurality of PS analysis results before and after to perform distortion compensation for each data symbol IS. Alternatively, the compensation coefficient CS may be averaged based on the PS analysis results before and after the data symbol. Even in this case,
Since the number (interval) of available PSs increases (decreases) as the number of mobile terminals increases, the quality of propagation path estimation is significantly improved. In this case, the delay amount of the delay circuit DL is appropriately selected according to the design.

In the first embodiment, the short codes S1 to Sn are replaced by the TCH1 to TCH in the base station.
Although the case of fixing to CHn has been described, the present invention is not limited to this. The base station can set an arbitrary short code S for each of TCH1 to TCHn. Further, the base station may notify the mobile device of one or more pieces of code information, timing information (frame transmission timing information) at which the code is used, and the like.

In the first embodiment, the case of spreading / de-spreading using a short code has been described.
Signal is double spread with short code and long code.
It may be despread. FIGS. 5 and 6 are diagrams (1) and (2) for explaining the mobile communication system according to the second embodiment.
The base station transmits the transmission frames of all the communication channels in the same phase, spreads each interpolation PS with only the code CC common to all the communication channels, and makes the data portion unique to each communication channel (a meaning different from each other). ) Codes C1 to Cn
In this case, each mobile station compensates for fading distortion or the like using an interpolated PS common to all communication channels (that is, the same code multiplexed signal of the PS).

FIG. 5A shows a partial configuration of the base station transmission system. The base station includes code generators CG1 to CG for spreading each communication channel signal with codes C1 to Cn (long code or short code) unique to each communication channel.
n and a multiplex signal CC common to all communication channels.
(Preferably a short code). The DEC of TCONT is
As shown in FIG. 6, in synchronization with the frame pulse signal FP of the base station, a timing signal TS1 such that output = 1 only in the data portion of each transmission slot, and a timing signal TS1 of each transmission slot
Timing signal TS2 such that output = 1 only in S part
And generate

TS1 is added to the code generators CG1 to CGn. In the section where TS1 = 1, each code C1 to Cn
Is spread only by the spreading code replica (preferably having a symbol period to a slot period).
On the other hand, TS2 is added to the code generator CGC,
In the section of = 1, the spreading of the PS unit is performed only by the spreading code replica of the code CC (preferably having one symbol long period).

FIG. 6 is a timing chart of the downlink. In each data section, a transmission multiplex signal MSTX spread with codes C1 to Cn unique to each communication channel is obtained. In each PS section, a transmission multiplex signal MS spread with a code CC common to all communication channels.
TX is obtained. FIG. 5B shows a partial configuration of the mobile terminal receiving system.

As described above, since the frame transmission phases of all communication channels of the base station are uniform, the configuration of CSR and TSR in FIG. 4A is deleted from the distortion compensator of the mobile station. For example, a code C1 is previously given to the CGa of the despreading / demodulating unit from the connection base station, and a common code CC is given to the CGA of the distortion compensating unit in advance for all communication channels. In addition, as in the case of the base station, the DEC of TCONT is synchronized with the frame pulse signal FP of the mobile station (corresponding to the frame pulse signal FP of the base station), and output = 1 only in the data portion of each receiving slot. And the PS of each slot received.
A timing signal TS2 is generated such that the output becomes 1 only in the portion.

TS1 is applied to the despreading / demodulating unit,
In the section of S1 = 1, the received data IS is demodulated by performing distortion compensation using the distortion compensation coefficient CS at each time point. On the other hand, TS2 is added to the distortion compensator and the TS2
In the section where = 1, a distortion compensation coefficient (or an average value thereof) CS is obtained based on the received PS, and the value is held during the subsequent data section. Alternatively, in the same manner as described in FIG. 22, the distortion compensation coefficient CS
Is interpolated.

As described above, according to the second embodiment, each PS portion is spread with only a common code CC for all communication channels, so that the code multiplex transmission power of each PS portion is equal to the number of mobile units during a call. Increased as the increase. On the other hand, on each mobile station side, the SN ratio of the despread PS (ie, E _b / I _o ) improves as the number of mobile stations during a call increases, and these PSs are improved.
It is possible to more accurately estimate a propagation path by fading or the like using a signal.

FIGS. 7 and 8 are diagrams (1) and (2) for explaining the mobile communication system according to the third embodiment, in which the base station spreads the PS portion only with the long code L1 unique to the base station. Then, the data portion is double-spread with the short codes S1 to Sn unique to each communication channel and the long code L1, and the mobile station compensates for fading distortion and the like using the PS portion common to all communication channels. Shows the case.

FIG. 7A shows a partial configuration of the base station transmission system. The base station includes a short code generator SCG1 to SCGn for spreading each downlink frame with a short code S1 to Sn unique to each communication channel, and a short code generator SCG1 to spread a multiplexed signal with a long code L1 unique to the base station. A long code generator LCG1. TCONT D
As shown in FIG. 8, the EC generates a timing signal TS1 such that the output becomes 1 only in the data portion of each transmission slot in synchronization with the frame pulse signal FP of the base station.

TS1 is an all short code generator SCG1
To SCGn, and in the section of TS1 = 1, the spreading of each transmission frame by the spreading code replica (preferably having a symbol period) of each of the short codes S1 to Sn is simultaneously energized. On the other hand, the long code generator LCG1 is always energized, and repeats spreading of the long code L1 by a spreading code replica (preferably having a frame period) in synchronization with the frame pulse signal FP.

FIG. 8 shows a downlink timing chart. In each data section, a transmission multiplexed signal MSTX double-spread by a short code S1 to Sn unique to each communication channel and a long code L1 unique to a base station is obtained by TS1 = 1. In each PS section, a transmission multiplex signal MSTX spread by only a common long code L1 for all communication channels of the base station is obtained by TS1 = 0.

FIG. 7B shows a partial configuration of the mobile station receiving system. The despreading / demodulating unit of the mobile station further includes a double despreading unit using a long code, and a long code L1 unique to the base station is previously given to the LCGc from the connected base station. For example, a short code S1 unique to the communication channel is provided. The long code L1 is given to the LCGA of the distortion compensator.
Further, the DEC of TCONT generates a timing signal TS1 such that the output becomes 1 only in the data portion of each reception slot in synchronization with the frame pulse signal FP of the mobile station, as in the case of the base station.

TS1 is applied to the despreading / demodulating unit,
Each received data IS in the section of 1 = 1 is demodulated by performing distortion compensation based on the distortion compensation coefficient CS at each time point.
On the other hand, the inverted signal / TS1 of TS1 is added to the distortion compensating section, and each distortion compensation coefficient (or their average value) CS is obtained based on each PS in the section of / TS1 = 1, and the value is calculated for the subsequent data section. Hold for a while. Or, in the same manner as described with reference to FIG.
The time series of the distortion compensation coefficient CS is interpolated.

As described above, according to the third embodiment, each PS portion is spread with the long code L1 unique to the base station, so that the code multiplex transmission power of the PS portion increases as the number of mobile stations during a call increases. It will be strengthened accordingly. On the other hand, on the mobile device side, the SN ratio of the despread PS is improved in accordance with the increase in the number of mobile devices during a call, and the propagation path can be more accurately estimated by fading or the like using these PS signals.

Further, in the CDMA cellular system, since this kind of long code L1 is usually used for color coding of each base station (cell), a special code for realizing this function is used from a finite code group. Needless to assign, the long code L1 can be utilized. 9 and 1
0 is a diagram (1) or (2) for explaining the mobile communication system according to the fourth embodiment, in which the base station spreads the PS portion with a short code SC common to all communication channels and the data portion communicates with each communication channel. Short codes S1 to S unique to each channel
n and a long code L1 unique to the base station.
The figure shows a case where the mobile station uses a common PS part to compensate for fading distortion and the like.

FIG. 9A shows a partial configuration of the base station transmission system. The base station includes a long code generator LCG1 unique to the base station, a short code generator SCGC common to all communication channels, and a switch SW for selecting these spread code replicas. Further, the timing signal T
S1 is also added to the switch unit SW, and the switch unit SW
Is connected to the a side when TS1 = 0, and is connected to the b side when TS1 = 1.

FIG. 10 shows a timing chart of the downlink. In each data section, TS1 = 1
Short codes S1 to Sn unique to each communication channel;
A transmission multiplex signal MSTX that is double-spread with the long code L1 unique to the base station is obtained. In the section of each PS, a transmission multiplex signal MSTX spread by only a short code SC (preferably having a symbol period) common to all communication channels is obtained by TS1 = 0.

FIG. 9B shows a partial configuration of the mobile terminal receiving system. A short code SC common to all communication channels (all mobile stations) is given in advance to the SCGA of the distortion compensator from the connected base station. The despreading / demodulating unit demodulates the received data IS unique to the mobile station in the section of TS1 = 1 by performing distortion compensation based on the distortion compensation coefficient CS at each time point. On the other hand, the distortion compensating unit obtains each distortion compensation coefficient (or their average value) CS based on the PS common to each mobile station in the section of / TS1 = 1, and holds the value for the subsequent data section. Alternatively, in the same manner as described in FIG. 22, the distortion compensation coefficient CS
Is interpolated.

As described above, according to the fourth embodiment, each PS portion is provided with a short code SC common to all communication channels.
Therefore, the code multiplex transmission power of the PS portion is increased as the number of mobile stations during a call increases. On the other hand, on the mobile device side, the SN ratio of the despread PS is improved in accordance with the increase in the number of mobile devices during a call, and the propagation path can be more accurately estimated by fading or the like using these PS signals.

Moreover, each PS part is a short code SC
Therefore, there is no worry that the signal level of the spread code replica is fixed to either one within one symbol section. FIGS. 11 and 12 are diagrams (1) and (2) illustrating a mobile communication system according to the fifth embodiment. The base station uses a short code SC common to all communication channels for the PS portion.
And double spreading with a long code L1 unique to the base station,
And a data portion is double-spread with a short code S1 to Sn unique to each communication channel and the long code L1,
Each mobile device uses a common PS portion to compensate for fading distortion and the like.

FIG. 11A shows a partial configuration of the base station transmission system. This base station includes a short code generator SCGC for spreading a multiplex signal with a short code SC common to all communication channels. Further, an inverted signal / TS1 of the timing signal TS1 is added to this SCGC, so that it is energized only when TS = 0.

FIG. 12 shows a timing chart of the downlink. In each data section, TS1 = 1
A transmission multiplex signal MSTX that is double-spread with a short code S1 to Sn unique to each communication channel and a long code L1 unique to the base station is obtained. In the section of each PS,
Since TS1 = 0, the transmission multiplex signal MSTX double-spread with the short code SC (preferably having a symbol period) common to all communication channels and the long code L1
Is obtained.

FIG. 11B shows a partial configuration of the mobile terminal receiving system. The configuration of this mobile device is basically the same as that of FIG. However, a short code SC common to all communication channels (all connected mobile devices) is given in advance to the SCGA of the distortion compensator from the connected base station. The despreading / demodulating unit demodulates the received data IS unique to each mobile station in the section of TS1 = 1 by performing distortion compensation based on the distortion compensation coefficient CS at each time point. On the other hand, the distortion compensator
Each distortion compensation coefficient (or their average value) CS is obtained based on PS common to each mobile station in the section of S1 = 1,
The value is held for the following data section. Alternatively, in the same manner as described with reference to FIG. 22, the time series of the distortion compensation coefficient CS is interpolated based on a plurality of PS analysis results before and after.

As described above, according to the fifth embodiment, each PS portion is provided with the short code SC common to all communication channels.
And a long code L1 unique to the base station.
The code multiplex transmission power of the PS portion is increased as the number of mobile stations during a call increases. On the other hand, the despreading P
The S / N ratio of S is improved according to the increase in the number of mobile stations during a call,
Using these PS signals, it is possible to more accurately estimate a propagation path due to fading or the like.

Further, since each PS portion is double-spread with the short code SC common to all communication channels and the long code L1 unique to the base station, each mobile station connected to the base station has another base station. There is no need to worry about interference from the PS part from the station. FIGS. 13 to 15 are diagrams (1) to (3) illustrating a mobile communication system according to the sixth embodiment.
Thus, the case where the base station spreads the first symbol of the downlink frame of the control channel with only the short code S0 common to the system (each cell) and spreads each of the other PSs with only the long code L1 unique to the base station. Is shown.

Here, a mobile communication system in which the control channel according to the present embodiment and the communication channel according to the third embodiment are combined will be described.
It is not limited to this combination. FIG. 13 shows a partial configuration of the base station transmission system. The basic configuration of the base station is the same as that of FIG.
Is added. This control channel is composed of a short code generator SCG0 for spreading a downlink transmission frame of the control channel with a short code S0 (preferably one symbol in length) common to the system, and a long code generator LCG1 at the subsequent stage. A long code generator LCG2 for canceling (masking) a part of the diffusion. The principle of masking a part of the double diffusion is shown in FIG.
This may be the same as that described in (A). The DEC of TCONT generates a timing signal TS3 such that the output becomes 1 only in the first symbol of the frame. And S
CG0 receives a logically ORed signal of TS1 and TS3, and LCG2 receives TS3.

FIG. 14 shows a timing chart of the downlink. The spreading pattern of all communication channels is the same as in FIG. Here, it is assumed that a plurality of pilot symbols PS are included in each hatched portion. Then, in the control channel CCH, one symbol at the head of the frame is spread with only the short code S0 common to the system by TS3 = 1. The data portion is double-spread with a short code S0 and a long code L1 unique to the base station. Then, the remaining PS portion is spread only by the long code L1. In this way, the first symbol of the control channel frame is spread by only the short code S0 common to the system, so that this one symbol can be transmitted when the power of the mobile device in the zone is turned on or when the mobile device handing over to the own zone is performed. Can be used for the synchronization capture symbol.

The first symbol of the control channel frame may be a symbol having the same code as the pilot symbol PS or a symbol representing another arbitrary code. Since the mobile station uses a perch as the base station having the highest received power, the spread code S0
As long as they match, the contents (signs) of the symbols do not matter. Therefore, preferably, one symbol at the head of the frame can have the same code as pilot symbol PS. In this case, the first symbol of the frame can also be used for propagation path estimation.

However, depending on the system, the first symbol of the frame may be a code other than the pilot symbol PS. In the present embodiment, a case where the code of the first symbol of the frame is different from the code of pilot symbol PS will be described. FIG. 15 shows a partial configuration of the mobile terminal receiving system. The code timing detection / identification unit detects long code synchronization timing by detecting the maximum correlation between the short code S0 common to the system and the first symbol of the frame, and subsequently identifies the base station. Also, during communication, synchronization with the communication channel is maintained. The details of the configuration and control of the code timing detection / identification unit can be considered in the same manner as those described with reference to FIGS. Then, TCONT generates timing signals TS1 and TS3 similar to those of the base station in synchronization with the frame pulse signal FP that has been established in synchronization.

In the despreading / demodulation unit, when receiving a control channel, a short code S0 common to the system is set in SCGa by a mobile unit control unit (not shown). The received multiplex signal MSRX at this time is in the section of TS1 = 1,
Each data part of the control channel is despread by the short code S0 and double despread by the long code L1. At the time of receiving a communication channel, for example, a short code S1 specified by a base station is set in SCGa. At this time, the received multiplexed signal MSRX has a short code S in each section of the communication channel in the section of TS1 = 1.
1 and are doubly despread by the long code L1.

In the distortion compensation section, A is an AND gate circuit, and NO is a NOR gate circuit. When the control channel is received (CCHC = 1), the code of the first symbol of the frame is different from the code of pilot symbol PS.
It is not used for channel estimation. LCGA, DEM at this time
And the operation of the coefficient determination unit is such that even if TS1 = 0, CC
Deactivated by HC = 1 * TS3 = 1. Other T
In the section of S1 = 0, the received multiplex signal MSRX is despread only by the long code L1. However, since this long code L1 is common to each downlink channel during communication of the base station, the PS portion of each channel during communication is also despread at the same time. Therefore, even at the time of receiving the control channel, the SN ratio of the despread PS increases according to the increase in the number of mobile stations during communication.

When receiving a communication channel, each TS1
In the section of = 0, each PS portion of each communication channel of the base station is despread from the received multiplexed signal MSRX only by the long code L1. Therefore, as described above, when receiving a communication channel, the SN ratio of the despread PS increases with an increase in the number of mobile stations during communication. However, in this example, since each PS portion excluding the first symbol from the control channel that is always used is despread only by the long code L1, even if the number of mobile units during communication is one, the PS portion is not used. There is an effect that the reception SN is improved.

FIGS. 16 to 18 are diagrams (1) to (3) for explaining the mobile communication system according to the seventh embodiment, in which the base station sets the first symbol of the control channel frame to the short code S0 common to the system. In addition to the case where only the PS is spread, the other PSs are spread with the short code S0 and the long code L1 unique to the base station. Here, a mobile communication system in which the control channel according to the present embodiment is used together with the communication channel according to the fifth embodiment will be described, but the present invention is not limited to this. For example, it may be used together with the communication channel according to the fourth embodiment. In this embodiment, a case will be described in which the code of the first symbol of the frame is the same as the code of pilot symbol PS.

FIG. 16 shows a partial configuration of the base station transmission system.
SCG0 of the control channel CCH spreads each data portion in the section of TS1 = 1 with the short code S0 common to the system (preferably of one symbol period), and SCGC of the multiplex channel sets each PS in the section of TS1 = 0. The part is spread with the short code S0. Therefore, the frame of the control channel is continuously spread by the short code S0. The multiplex channel LCG1 is always energized, and the control channel frame is double-spread with the long code L1. However, if LCG2 of the control channel is TS
Since it is activated at the timing of 3, double spreading by the long code L1 of the first symbol of the control channel frame (= PS in this example) is masked.

FIG. 17 shows a downlink timing chart. The spreading pattern of all communication channels is the same as in FIG. However, also here, it is assumed that a plurality of pilot symbols PS are included in each hatched portion. As for the control channel CCH, the first symbol (= PS) at the beginning of the frame is spread by only the short code S0 common to the system by TS3 = 1. Remaining data part and PS
The part is doubly spread with a short code S0 and a long code L1 unique to the base station. In this way, by spreading one symbol at the head of the control channel frame with only the short code S0 common to the system, this one symbol can be transmitted when the power of the mobile device in the zone is turned on or when the mobile device handing over to the own zone is performed. Can be used for the synchronization capture symbol.

FIG. 18 shows a partial configuration of the mobile station receiving system.
The configurations of the code timing detection / identification unit and the despread / demodulation unit may be the same as those in FIG. On the other hand, the configuration of the distortion compensator is slightly different since the first symbol (= PS) of the control channel frame can be used for channel estimation. The operations of the SCGA, LCGA, DEM, and coefficient determination unit are energized in each section of TS1 = 0. However, when the control channel is received (CCHC = 1), the first symbol (= PS) of the control channel is spread only with the short code S0 common to the system. * By TS3 = 1, the switch SWA is connected to the contact b side. As a result, only the first symbol of the control channel is despread with only the short code S0. Otherwise, switch SWA is contact a
To the side. As a result, the remaining PS portion of the control channel and each PS portion of the communication channel are double-spread with the short code S0 and the long code L1.

Needless to say, the seventh embodiment can provide the same functions and effects as those of the sixth embodiment. Further, since each PS is spread solely or doubly, any PS signal is sufficiently spread spectrum by the short code S0. By the way, in each of the second to fifth embodiments, the frame transmission phases of all communication channels are uniform, and the spreading pattern of each PS portion is common to all communication channels. Therefore, the base station performs control such that the transmission power before or after code multiplexing of the PS portion is reduced according to the increase in the number of mobile stations during a call.

Since the number of mobile units during a call is known at the base station, the base station can optimally obtain the transmission power of the PS signal at that time. For example, if the transmission power of the PS part is controlled to 1 / (the number of mobile units during a call), the P received by the mobile unit
The despread signal power of the S signal is the same as the despread signal power of the data part of the channel during communication. Therefore, no special level adjustment is required in the distortion compensator.

On the other hand, the base station in this case can reduce the transmission power of the PS section, thereby saving the transmission power and reducing the interference of the PS section with another base station (cell).
In the above embodiments, the operation at a single frequency has been described, but the present invention can also be applied to a case where each base station has a plurality of code channels at a plurality of frequencies.

Although the preferred embodiments of the present invention have been described, it is to be understood that various changes can be made in the structure and control of each unit and various combinations thereof without departing from the spirit of the present invention. Not even.

[0100]

As described above, according to the present invention, it is possible to greatly improve the propagation path estimation accuracy in the interpolation pilot system with a simple configuration, thereby contributing to the improvement of the communication service quality of the DS-CDMA mobile communication system. large.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram (1) illustrating a mobile communication system according to the first embodiment.

FIG. 3 is a diagram (2) illustrating the mobile communication system according to the first embodiment.

FIG. 4 is a diagram (3) illustrating the mobile communication system according to the first embodiment.

FIG. 5 is a diagram (1) illustrating a mobile communication system according to a second embodiment.

FIG. 6 is a diagram (2) illustrating the mobile communication system according to the second embodiment.

FIG. 7 is a diagram (1) illustrating a mobile communication system according to a third embodiment.

FIG. 8 is a diagram (2) illustrating a mobile communication system according to a third embodiment.

FIG. 9 is a diagram (1) illustrating a mobile communication system according to a fourth embodiment.

FIG. 10 is a diagram (2) illustrating a mobile communication system according to a fourth embodiment.

FIG. 11 is a diagram (1) illustrating a mobile communication system according to a fifth embodiment.

FIG. 12 is a diagram (2) illustrating a mobile communication system according to a fifth embodiment.

FIG. 13 is a diagram (1) illustrating a mobile communication system according to a sixth embodiment.

FIG. 14 is a diagram (2) illustrating a mobile communication system according to a sixth embodiment.

FIG. 15 is a diagram (3) illustrating a mobile communication system according to a sixth embodiment.

FIG. 16 is a diagram (1) illustrating a mobile communication system according to a seventh embodiment.

FIG. 17 is a diagram (2) illustrating a mobile communication system according to a seventh embodiment.

FIG. 18 is a diagram (3) illustrating a mobile communication system according to a seventh embodiment.

FIG. 19 is a diagram (1) illustrating a conventional technique.

FIG. 20 is a diagram (2) explaining a conventional technique.

FIG. 21 is a diagram (3) illustrating a conventional technique.

FIG. 22 is a diagram (4) explaining a conventional technique.

[Explanation of symbols]

 BS base station CCG common code generator CG code generator CSR code shift register CTR counter DEC timing decoder DEM primary demodulator DL delay circuit FB frame buffer LCG long code generator MOD primary modulator MIX mixer (multiplying circuit) MS Mobile device SCG Short code generator TCONT Timing controller TSR Timing shift register + Signal multiplexing circuit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuo Kawabata 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Kazuo Obuchi 4 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture 1-1 1-1 Fujitsu Co., Ltd. (72) Inventor Hiroaki Iwamoto 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Co., Ltd. (72) Inventor Yoshiharu Tajima 4 Ueodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 1-1 1-1 Fujitsu Limited (72) Inventor Kenji Suda 4-1-1 1-1 Kamiodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yasuyuki Oishi 4 Ueodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Koji Matsuyama 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fuji The Corporation

Claims (9)

[Claims] 1. A base station apparatus and a mobile terminal apparatus, each of which has a DS-C
In a mobile communication system in which the mobile terminal device estimates a signal propagation path characteristic based on a known pilot signal interpolated in a downlink frame of a communication channel by the base station device, wherein the base station device is connected by a DMA method, Each downlink frame in which a common pilot signal is interpolated in a common format is transmitted by shifting the transmission timing by at least the interpolated pilot signal for each of the communication channels used by one or more mobile terminal devices. A mobile communication system, wherein the mobile terminal device estimates a signal propagation path characteristic based on a time series of an interpolation pilot signal of each downlink frame. 2. A base station apparatus and a mobile terminal apparatus, each of which has a DS-C
In a mobile communication system in which the mobile terminal device estimates a signal propagation path characteristic based on a known pilot signal interpolated in a downlink frame of a communication channel by the base station device, wherein the base station device is connected by a DMA method, Each downlink frame in which one or more common pilot signals are interpolated in a common format is transmitted in the same phase to each communication channel used by one or more mobile terminal devices, and each downlink frame is transmitted. The mobile terminal device despreads the interpolated pilot signal of each of the spread downlink frames with a code common to the all communication channels. A mobile communication system, comprising: 3. The base station apparatus spreads an interpolated pilot signal of each downlink frame with only a common long code in all communication channels of the base station, and transmits other intraframe signals with the long code and each communication signal. 3. The mobile communication system according to claim 2, wherein double spreading is performed with a short code unique to a channel. 4. The base station apparatus spreads an interpolated pilot signal of each downlink frame with only a first short code common to all communication channels of its own station, and spreads other intra-frame signals of all its own frames. 3. The mobile communication system according to claim 2, wherein double spreading is performed with a long code common to communication channels and a second short code unique to each channel during communication. 5. The base station apparatus double-spreads an interpolated pilot signal of each downlink frame with a first short code common to all communication channels of its own station and a long code common to all communication channels of its own station. 3. The mobile communication system according to claim 2, wherein the other intra-frame signals are double-spread with the long code and a second short code unique to each channel during communication. 6. The base station apparatus further comprises a control channel for transmitting a downlink frame having a format common or substantially common to the communication channel of the base station with respect to the interpolation pilot signal in the same phase as the communication channel. At least one leading symbol of the downstream frame is spread only with a short code common to the system, and the remaining interpolated pilot signals are spread only with a long code common to all communication channels of the own station.
4. The mobile communication system according to claim 3, wherein other intra-frame signals are double-spread with a short code common to the system and a long code common to all communication channels of the own station. 7. The base station apparatus further includes a control channel for transmitting a downlink frame having a format common or substantially common to a communication channel of the base station with respect to an interpolation pilot signal in the same phase as the communication channel. A first short code common to all communication channels of the control channel is defined as a first short code common to the system, and at least one leading symbol of a downlink frame of the control channel is spread only by the first short code, and 6. The mobile communication system according to claim 5, wherein intra-frame signals other than the above are double-spread with a long code common to all communication channels of the own station and the first short code. 8. The base station apparatus according to claim 2, wherein the base station apparatus reduces the transmission power of the interpolated pilot signal of each communicating channel according to an increase in the number of communicating channels. Mobile communication system. 9. The base station apparatus and the mobile terminal apparatus are provided with a DS-C
The mobile terminal device of the mobile communication system, wherein the mobile terminal device is connected by a DMA system and the base station device estimates a signal propagation path characteristic based on a known pilot signal interpolated in a downlink frame of a communication channel, The base station apparatus despreads and demodulates a common interpolated pilot signal spread in the same phase with a common code for each communication channel used by one or more mobile terminal apparatuses, using the common code. A distortion compensating unit for calculating a distortion compensation coefficient of a signal propagation path, and the base station apparatus despreads a data signal spread with a unique code for a specific communication channel with the unique code, and uses the distortion compensation coefficient. A data demodulation unit for demodulating a data signal by using a mobile terminal device.