JP2000059286A - Mobile station equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make mobile station equipment able to efficiently measure the noise (interference signal) power of the present station without reserving a specified spread code for interference power measurement in a system. SOLUTION: In this mobile station equipment of a mobile communication system for which a base station and plural mobile stations inside the service area are connected by a DS-CDMA (direct spread-code division multiple access) system, transmission signals from the base station are spread by mutually orthogonal codes and all transmission timings are synchronized, a signal power measurement part for measuring signal power around the center frequency for signals for which the reception signals r(t) of the present station are inversely spread by a specified spread code Ci is provided. Further, a measurement control part for successively measuring each corresponding signal power (p) through the signal power measurement part for all the spread codes c1-cN usable inside the service area and judging that the spread code Ck corresponding to minimum signal power among the obtained signal power is in nonuse inside the service area is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a mobile station device,
More specifically, a base station and a plurality of mobile stations within its service area are connected by the DS-CDMA system, transmission signals from the base station are spread by mutually orthogonal codes, and all transmission timings are synchronized. The present invention relates to a mobile station device of a mobile communication system.

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), DS-CDMA (Direct Spre) which is superior in fading countermeasure and can accommodate more subscribers.
Ad-Code Division Multiple Access) mobile communication systems have been actively researched and developed.
The present invention is suitable for application to a DS-CDMA mobile station apparatus.

[0003]

2. Description of the Related Art FIGS. 10 to 12 are diagrams (1) to (3) for explaining the prior art, and FIG. 10 shows a communication model of the DS-CDMA system. In the figure, transmission data a ₁ (t) of a mobile station (MS1) is subjected to primary modulation (for example, BPSK modulation) by a primary modulator to become a primary modulated signal b ₁ (t),
Further, the secondary modulation (code spreading) is performed by the secondary modulator with the PN spread signal c ₁ (t) corresponding to the spread code C ₁ to become the secondary modulated signal s ₁ (t), which is transmitted from the antenna.

On the other hand, in the antenna of the base station (BS), in addition to the reception wave s ₁ (t) from the MS ₁ , the reception waves s ₂ (t) to s s from the other MS 2 to MSm during simultaneous communication.
_m (t) is multiplexed and received, and the thermal noise n
(T) is added to become a received input signal r (t). This reception input signal r (t) can be expressed by the following equation.

[0005]

(Equation 1) Here, P is the average power, a center frequency of f _c is a primary modulation signal, θ _i (t) is the transmitted data _{a 1 (t) = 0/} 1 on a corresponding phase (0 / [pi), the phi _i 0 It is a random phase uniformly distributed to ２2π.

Further, the received input signal r (t) is secondarily demodulated (code despread) by a secondary demodulator using a PN spread signal c ₁ (t) corresponding to the same spread code C ₁ as described above.
It becomes the secondary demodulated signal x (t). This secondary demodulated signal x
(T) can be expressed by the following equation.

[0007]

(Equation 2) Here, the first term on the right side of x (t) is a desired signal component, the second term is an interference (non-desired) signal component, and the third term is c.
₁ Thermal noise diffused at (t). Further, the secondary demodulated signal x (t) is subjected to primary demodulation (BPSK demodulation) by a primary demodulator to become received data y (t).

[0008] When a large number of subscriber calls are simultaneously made by such a DS-CDMA system, a difference in the distance between the BS and each MS becomes a problem. FIG. 11 shows DS-
This is a diagram for explaining a so-called near-far problem in the CDMA system, and is specifically described below.

[0009] In FIG. 11 (A), MS1~MS3 is respectively from BS at a distance d ₁ to d _3, wherein, d
₁ <and d ₂ <d _3.

In FIG. 11 (B), BSs are MS1-M
Spread by a unique code C ₁ -C ₃ each primary modulation signal addressed S3 b ₁ (f) ~b ₃ and (f) respectively, resulting secondary modulated signal s ₁ (f) ~s ₃ ( f) at the same time. At this time, it is assumed that the transmission powers of the secondary modulation signals s ₁ (f) to s ₃ (f) are equal. On the other hand, in MS1, the reception input signal r
₁ (f) to r ₃ (f) are despread by code C ₁ to obtain 2
A next demodulated signal x ₁ (f) is generated. In addition to the desired signal component r ₁ (f), r ₂ (f), r
₃ (f) the interference signal is component is also included, these interfering signal components because not despread by the code C _1, the final reception data y ₁ (t) can be correctly reproduced. Similarly, MS2 in the received data y ₂ (t) can correctly reproduce, also correctly reproduces the received data y ₃ In MS3 (t).

In FIG. 11C, the MS ₃ spreads the primary modulation signal b ₃ (f) addressed to the BS with the code C ₃ and transmits the obtained secondary modulation signal s ₃ (f). Although not shown, each of the secondary modulated signals s
₁ (f) and s ₂ (f) are transmitted simultaneously. Now, MS1
Assuming that each transmission power of MS3 is equal, M
Since there is a relation of d ₁ <d ₂ <d ₃ for each distance from S1 to MS3, each reception input signal in the BS has a relation of r ₁ (f)> r ₂ > r ₃ (f). Therefore, sufficient amplitude (power) cannot be obtained in the secondary demodulated signal x ₃ (f) from the distant MS 3, so that the received data y ₃ (t) may not be correctly reproduced finally.

Therefore, conventionally, in order to solve such a near-far problem, the BS monitors each received input (desired signal power) from MS1 to MS3, and sets the MS1 so that each received input in the BS becomes uniform. ＭＳMS3 are remotely controlled. On the other hand, in each of MS1 to MS3, BS
, And remotely controls the transmission power of the BS so that a sufficient reception input can be obtained in each of the MS1 to MS3. In particular, DS-C
In the DMA system, it is necessary to accurately perform the above-described remote control of the transmission power in order to increase the number of simultaneous calls in a cell. For this purpose, it is necessary to separate the desired signal power from the reception input of the own station.

Further, in the DS-CDMA system, a fading countermeasure is performed by performing maximum ratio combining in consideration of interference signal power by diversity combining or RAKE combining. FIG. 12 is a diagram illustrating an example of fading countermeasures.

In FIG. 12A, in the mobile communication system, radio waves from the BS are input to the MS 1 in various phases by being reflected directly and on the ground or a building, so that it is necessary to take measures against fading. In the DS-CDMA system, fading countermeasures can be efficiently realized using a matched filter and a transversal filter.

FIG. 12B shows an example of the configuration of a secondary demodulation unit. In the figure, reference numeral 29a denotes a matched filter,
29b is a transversal filter. In matched filter 29a, receives the input signal r (t) with the input to the delay line, PN spread signal (+1 output signal of each tap provided at intervals of chip period △ t which corresponds to the code C _i , -1), and their respective output signals are multiplexed and input to the filter F matched to the chip period Δt.

In such a configuration, when the received input signal r (t) spread with the code C _i just enters the full delay line, a peak despread with the code C _i appears at the combined output. In this case, since the direct wave and the reflected wave are actually input to the delay line with different phases, the peak of the combined output also appears according to the input phase of each signal. Thus, for example the timing t ₀ the direct wave peak, the t ₁ a first reflected wave peak, the t ₂ a second reflected wave peak, the peak of the t ₃ a third reflected wave respectively emerge.

In the transversal filter 29b, the output signal of the filter F is input to the delay line, and the output signal of each tap is added to the weighting coefficient vector A.
(A ₀ , 0, a _1, etc.). The coefficient vector A is determined based on a signal power to noise (interference signal) power ratio for each tap signal based on a channel measurement signal (sounder) transmitted in advance or separately transmitted. You. Further, each multiplied output is added by an adder. In this way, the received input wave components of each phase are collected (diversity combined), and a secondary demodulated signal x (t) with an improved S / N ratio is obtained at the output of the transversal filter 29b.

As described above, when performing diversity combining or rake combining, it is necessary to accurately determine the signal power to interference power ratio (SIR). For this purpose, the desired signal power is separated from the reception input of the own station. There is a need.

Conventionally, in order to estimate accurate noise (interference signal) power, the reception input of the own station is despread with a spreading code not used for data communication to obtain an interference signal component. I have. That is, when the reception input r (T) of the own station is secondarily demodulated by the code C _k which is not used in the cell, 2
The next demodulated signal x (t) can be expressed by the following equation.

[0020]

(Equation 3) Here, the desired signal power does not appear, the first term on the right side of x (t) is an interference (unwanted) signal component, and the second term is thermal noise.

Conventionally, one spreading code has been reserved in the system in advance for measuring interference power, and each MS has measured the interference signal power using this reserved code.

[0022]

However, if one spreading code is reserved in the system for measuring the interference power, the number of spreading codes used for data communication is reduced by one.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to reduce the noise (interference) of the own station even if the system does not reserve a specific spreading code for measuring interference power. It is an object of the present invention to provide a mobile station device capable of efficiently measuring (signal) power.

[0024]

The above-mentioned problem is solved, for example, by referring to FIG.
Is solved. That is, in the mobile station device of (1) of the present invention, the base station is connected to a plurality of mobile stations in the service area by the DS-CDMA system, and the transmission signal from the base station is spread by mutually orthogonal codes. It is, and the mobile station apparatus in a mobile communication system in which all the transmission timing is synchronized, measure the signal power in the vicinity of the center frequency per signal despread received signal r of the own station (t) at the specified spreading codes C _i And a corresponding signal power p is sequentially measured via the signal power measurement unit for all spread codes C _{1 to} C _N that can be used in the service area, and among the obtained signal powers, minimum spreading code C _K corresponding to the signal power within the service area in which and a determining measurement control unit and during non-use.

According to the present invention (1), since the mobile station apparatus can detect a spreading code that is not being used in the service area by searching for itself, the system (or cell) reserves a specific spreading code in advance. This is not necessary, and the entire spreading code of the system (or cell) is effectively used.
Further, if an unused spreading code is found in the service area, the interference signal power of the own station can be accurately measured, and thus the desired signal power can be accurately separated from the reception input of the own station.

Preferably, in the present invention (2), in the above-mentioned present invention (1), the measurement control unit further determines a signal power of each of the obtained signal powers which is lower than a predetermined reference value as a minimum value determination target. And According to the present invention (2), the reliability of the process of detecting an unused spreading code in the service area is improved by further setting a value smaller than the predetermined reference value as a minimum value determination target.

Preferably, in the present invention (3), in the above-mentioned present invention (2), the measurement control unit obtains an average value of each signal power below a predetermined reference value, and calculates an average value of the interference power of the own station. Power (including thermal noise). Therefore, the reliability of the interference signal power of the own station is improved.

Further, in the mobile station apparatus according to the present invention (4), the base station and a plurality of mobile stations within the service area are connected to the DS-CD.
In a mobile station apparatus of a mobile communication system connected by the MA system, in which a transmission signal from a base station is spread by a code orthogonal to each other and all transmission timings are synchronized, a reception signal r (t) of the own station is transmitted. A signal power measuring unit for measuring the signal power near the center frequency of the signal despread with the designated spreading code C _i , and a signal power measuring unit for all the spreading codes C _{1 to} C _N that can be used in the service area The corresponding signal powers p are sequentially measured, and the subsequent measurement of the signal power is stopped when the signal power below the predetermined reference value is measured, and the spreading code C corresponding to the signal power below the predetermined reference value is stopped. And a measurement control unit that determines that _K is not being used in the service area.

According to the present invention (4), when a signal power below a predetermined reference value is measured, the corresponding spreading code is not only likely to be unused in the service area, but also thereafter. Since the measurement of the signal power (that is, the search for the unused code) is terminated, the search for the unused code can be performed efficiently.

Preferably, in the present invention (5), in the above-mentioned present inventions (2) to (4), the predetermined reference value is a spreading code used by the own station or another station. This is a value determined based on the signal power around the center frequency obtained for the despread signal. Here, the value determined based on the signal power near the center frequency is, for example, a value that is １ ／ of the signal power near the center frequency. Therefore, when a signal power below such a predetermined reference value is measured, there is a high possibility that the corresponding spreading code is unused in the service area.

The predetermined reference value in the present invention (2) to (4) is not limited to the predetermined reference value according to the present invention (5), but may be a predetermined (fixed) reference value predetermined by a system or the like. It may be.

Further, in the mobile station apparatus according to the present invention (6), the base station and a plurality of mobile stations in the service area are connected to the DS-CD.
In a mobile station apparatus of a mobile communication system connected by the MA system, in which a transmission signal from a base station is spread by a code orthogonal to each other and all transmission timings are synchronized, a reception signal r (t) of the own station is transmitted. , A spreading code C not used in the service area searched by the own station or notified by the base station.
_A first signal power measuring unit for measuring a _first signal power p ₁ near the center frequency from the signal despread by _K ;
The received signal r (t) of the own station is used as the spreading code C used by the own station.
a second signal power measuring unit for measuring a _second signal power p ₂ near the center frequency from the signal despread by _i ;
Remote control of the base station transmission power and notifies the transmission power control information determined based on a desired signal power of the own station obtained from the second signal power p ₂ by subtracting the first signal power p ₁ to the base station Unit.

According to the present invention (6), the spreading code C _{K which} is not used in the service area is searched for by the own station or notified from the base station, so that all spreading codes can be utilized.
The remote control unit may use the spreading code C _K in unused second signal power using the spreading code C _i in use from p ₂ (total received signal power of the own station) within the service area in the own station the first signal power by subtracting the p ₁ (interference signal power of the own station), along with the desired signal power of the own station is obtained precisely, the transmission power control information determined from the desired signal power and interference power of the local station By appropriately notifying the base station (for example, ± α dB is required from the present time), the transmission power of the base station to its own station can be accurately and remotely controlled.

Further, in the mobile station apparatus according to the present invention (7), the base station and a plurality of mobile stations in the service area are connected to the DS-CD.
In a mobile station apparatus of a mobile communication system connected by the MA system, in which a transmission signal from a base station is spread by a code orthogonal to each other and all transmission timings are synchronized, a reception signal r (t) of the own station is transmitted. , A spreading code C not used in the service area searched by the own station or notified by the base station.
_A first signal power measuring unit for measuring a _first signal power p ₁ near the center frequency from the signal despread by _K ;
The received signal r (t) of the own station is used as the spreading code C used by the own station.
a second signal power measuring unit for measuring a _second signal power p ₂ near the center frequency from the signal despread by _i ;
And a secondary demodulation unit for obtaining each tap coefficient for diversity combining the received signal of the own station based on the first and second signal powers p ₁ and p ₂ and performing diversity combining.

According to the present invention (7), the spreading code C _{K which} is not used in the service area is searched for by the own station or notified by the base station, so that all spreading codes can be utilized.
Further, the secondary demodulation unit uses the spreading code C _K which is not used in the service area and the first and second signal powers p ₁ and p ₂ using the spreading code C _i which is being used by the own station, to control the local station. It is possible to accurately determine each tap coefficient for diversity combining the received signals of the above, and thus to appropriately perform diversity combining.

[0036]

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.

FIG. 2 is a diagram showing a configuration of the mobile communication system according to the embodiment. In the drawing, reference numeral 10 denotes a mobile station (MS).
1) and 11 are speakers (S), 12 is a microphone (M), 1
3 is a baseband processing unit (BBP), 14 is a codec (CODEC), 15 is a CDMA control unit for performing timing control and format conversion by DS-CDMA, 16 is a primary modulation unit by BPSK, for example, 17
Is a code signal generator (CG) for generating a PN spread signal corresponding to the spread code C _i ′, 18 is a secondary modulator (code spreader), 19 is an attenuator (ATT), and 20 is D / D
A converter (D / A), 21 is a frequency converter (FCV),
22 is a transmission amplifier (TXA), 23 is a transmission / reception switch (C), 24 is an antenna, 25 is an RF amplifier (RF
A) and 26 are frequency converters (FCV), 27 is a synchronization detector for detecting and maintaining the DS-CDMA signal synchronization using a matched filter or the like, and 28 is a code signal generator (C
G) and 29 are secondary demodulation units (code despreading units), and 30 is a primary demodulation unit based on, for example, the BPSK method.

Further, reference numeral 31 denotes a main control (including transmission power control using the ATT 19) and various processing (call processing, unused code detection processing to be described later), base station control (not shown) including a CPU and a memory (not shown). Terminal control unit for performing remote control processing of station transmission power), a console unit 32 having a keyboard unit such as an LCD display unit and dial keys (not shown), a code signal generation unit (CG) 33, and a reception input signal 34 Is a common bus of the terminal control unit (CPU).

Further, 40 is a base station (BS), 41 is a communication control unit for controlling communication between the network side and the radio channels CH _{1 to} CH _n , and 42 _{1 to} 42 _n are primary modulation units and secondary modulation units. (Code spreading unit), 43 ₁ to 43 _n are despreading demodulation units including a secondary demodulation unit (code despreading unit) and a primary demodulation unit, 44 is a transmission / reception sharing unit, and 45 is an antenna. ,
Reference numeral 50 denotes an office line connected to a mobile switching center (not shown).

In the MS 1, the audio signal from the microphone 12 is converted into a PCM signal by the BBP 13 and
At 14, it is converted to a voice code, converted to a transmission format by a CDMA control unit 15, BPSK modulated by a primary modulation unit 16, code-spread by an uplink code C _i ′ by a secondary modulation unit 18, and transmitted by an ATT 19. The power is adjusted,
The signal is converted to an RF frequency by the FCV 21, amplified by the TXA 22, and transmitted from the antenna 24 via the C.

At the BS, reception R from antenna 45
F signal, pre-processing by the transmission and reception common unit 44 (RF amplification, frequency conversion, etc.) are secondary demodulated by the code C _i 'for uplink despreading demodulator 43 _i (code despreading) and the primary demodulating The format is converted by the communication control unit 41 and transmitted to the other party (not shown) via the office line 50.

On the other hand, in the BS, the received signal from the other party is converted in format by the communication control unit 41, and the like.
Modulation and spreading section 42 codes for primary modulation and downlink in _i C _i
Are subjected to secondary modulation (code spreading) by the
Is converted to transmission power control and radio frequency by the antenna 4
5 is transmitted.

In the MS 1 again, the RF signal received from the antenna 24 is transmitted to the RFA 25 by the RFA 25 via the C 23.
Amplified, converted into IF frequency FCV26, by the code C _i for the downlink in the secondary demodulator 29 are secondary demodulation (code despreading), the primary demodulating the primary demodulation unit 30, CD
The format is converted by the MA control unit 15 and CODEC
The signal is converted to a PCM signal at 14, converted to an audio signal at BBP 13, and output to the speaker 11.

Although not shown, a BS is arranged in each cell under the cellular system, and the BS is in charge of a radio service in its own cell (service area). The synchronization between the BSs is asynchronous, for example, and the MS in the cell synchronizes with the nearest (signal power maximum) BS.

FIG. 3 is a diagram illustrating a communication format of the mobile communication system according to the embodiment. This BS is 1
One control channel CCH and up to N-1 communication channels TCH1 to TCHN-1 can be accommodated.
It required traffic channel according to the S number (i.e., code C ₂ ~
C _N ). 1 frame (e.g. 10 ms) is divided into m time slots TS1～TSm, also all codes C ₁ -C _N are orthogonal to each other.

The top portion of the downlink control channel CCH-D (hatched portion), a mobile communication system (i.e., all the cells) is spread only with a common short code C _1, the thus same in the BS for each MS which cell It can synchronize with a short code C ₁ of. The rest of the downlink control channel CCH-D, although not shown, is spread doubly with a unique long code L ₁ to the BS by a known method. Accordingly, each MS can identify each BS (cell) by the combination long code L _1. On the other hand, with respect to the uplink control channel CCH-U, all of one frame is double-spread with the short code C ₁ ′ and the long code L ₁ .

The downlink traffic channel TCH1-D short codes every one frame of C ₂ and long code L ₁
And the uplink traffic channel TCH1-U
Is double-spread with the short code C ₂ ′ and the long code L ₁ in one frame. Other call channel T
The same applies to CH2 to TCHN-1.

In the following description, for example, the code C ₁
In this case, the uplink and downlink codes C ₁ ′ and C ₁ are included. Also, the above communication format is an example,
Various other communication formats can be adopted.

FIG. 4 is a diagram for explaining a power measuring unit according to the embodiment. FIG. 4A shows the configuration of the power measuring unit 34. In the figure, 71 is despreader (multiplier) 72 band-pass filter that passes the vicinity of the center frequency f _c of the despread signal x (t) (BPF), 73 is detected to envelope detection output signal of BPF72 74, an A / D converter (A / D), 75, an adder, 76, a register (RE
G) and 77 are dividers (DIV).

The received signal r (t) is despread by the despread signal c (t) corresponding to the code C _k, the signal component in the vicinity of the center frequency f _c in BPF72 than its output signal is extracted, its output signal The envelope is detected by the detector 73. Although this detection output is in the dimension of voltage, it is referred to as power for convenience of explanation. Further, this detection output is supplied to the A / D converter 74.
, And the output signal is cumulatively added (integrated) to the REG 76 via the adder 75. The cumulative addition section is set to, for example, one or two or more frame sections, one or two or more time stop sections, or one or two or more symbol sections by a timing controller (not shown). Then, the accumulated output of the REG 76 is divided by the number of symbols in the corresponding section by the DIV 77, and thus the average power p per symbol is output.

[0051] FIG. 4 (B) shows a case where the despreading code C _i in using the received signal r (t). Since the despread signal x (t) in this case has a sufficient signal power (desired signal power) near f _C , its detection output is also large, which is substantially equal to the desired signal power (including the interference signal power) p. It corresponds to _i .

FIG. 4C shows a case where the received signal r (t) is despread by a code C _k which is not used in the cell. Since the despread signal x (t) in this case does not have sufficient signal power (desired signal power) near f _C (that is, the desired signal remains spread), its detection output is also small, which is approximately the same. It corresponds to the interference signal power p _k.

Therefore, the desired signal power (not including the interference signal power) is obtained by the calculation of p _i -p _k , and the signal power to noise (interference signal) power ratio is (p _i -p _k ) /
determined by the calculation of p _k.

Although the power measuring section 34 of the above-described example has been described, the power measuring section 34 can be variously configured by, for example, a high-speed firmware calculation using a DSP.

FIG. 5 shows the configuration of the secondary demodulation unit according to the embodiment. The operations of the matched filter 29a and the transversal filter 29b may be the same as those described with reference to FIG. Here will be described operation of the tap coefficients a _0. As described above, at the timing of t ₀ , the peak of the despread output is obtained for the direct wave component. This was extracted band component (around f _c) at BPF81, and detected by the detection unit 82, to A / D conversion timing of t _0.
Then, the tap coefficient computing unit 84 (including thermal noise) interference signal power power measuring unit 34 has measured the p _1, timing the A / D-converted direct wave signal power (the desired signal of the t _0, interference determine a signal and a thermal noise) signal power to noise based on the p ₂ (interference signal) power ratio, to determine the tap coefficients a ₀ on this basis.

Although not shown, preferably, the above A
A / D converter 83 and a tap coefficient calculator 84 are provided in parallel for the number of taps, the first reflected wave component is A / D-converted at the timing of t ₁ , and the second reflected wave component is converted at the timing of t _2. The wave components are A / D converted, and the tap coefficients a ₁ ,
a ₂ is because in parallel, are respectively updated. Hereinafter, the same applies.

[0057] Figure 6 is a flow chart of unused code detection processing according to the first embodiment, the code when the secondary demodulation power in the vicinity of the center frequency f _c is minimized shows a case where determined that the non-use I have. In step S1, the index register I is initialized to 0, and the maximum value _pmax is set in the minimum value register _PMIN for holding the minimum value of the secondary demodulation power. In step S2, the code C (I) is read from the address indexed by the register I of the code table.

The code table is shown in the inset (a). I
N codes C _{1 to} C _N (including uplink and downlink) that are likely to be used in the mobile communication system or the service area of the BS are stored in addresses = 0 to N−1. All these codes are stored in advance in the ROM or the like of the MS 1 or are notified from the BS when the MS 1 enters the service area of the BS and stored in the RAM or the like.

In step S3, the code C (I) is set in the PN signal generator 33. The CG 33 having received the code C (I) in synchronization with the trigger signal TG of the synchronization control unit 27
Generates a despread signal c (t) corresponding to The power measuring unit 34 converts the received input signal r (t) into a despread signal c (t).
To obtain a secondary demodulated signal x (t).

At this time, if the code C (I) is being used in the service area of the BS, the secondary demodulated signal x (t) described in the above [Equation 2] is obtained, and the signal x (t) is obtained. ) is the peak voltage corresponding to the desired signal component in the vicinity of the center frequency f _c is detected. Preferably, the detection signal is averaged for one or more frames, slots, or symbols to determine a secondary demodulation power p. At this time, if the code C (I) is not used in the service area of the BS, the secondary demodulated signal x (t) described in the above [Equation 3] is obtained, and this is the interference signal power ( Thermal noise).

In step S4, the end of the measurement is waited. When the measurement is completed, the measured power p is obtained in step S5. In step S7, it is determined whether or not p <P _MIN . p
If <P _MIN , set p to P _MIN in step S7 and save it in code C (I). If p <P _MIN is not satisfied, the process of step S7 is skipped.

In step S8, +1 is added to the register I.
In step S9, it is determined whether or not I ≧ N, and if not, the process returns to step S2 to acquire the next spreading code and perform the same processing as described above. Thus, step S9
When it is determined that I ≧ N, the secondary demodulated signal has been obtained for all spread codes, and this processing is terminated. At this time, the minimum value of the measured power p is stored in the minimum value register P _MIN , and the corresponding code C (I) is stored in the memory.

[0063] Figure 7 is a flow chart of unused code detection processing according to the second embodiment, the code when the secondary demodulation power in the vicinity of the center frequency f _c is the smallest among those Ru below the predetermined reference value not The case where it is determined that the device is in use is shown.

In step S11, the own station (other stations may be used)
In the code C _i in use is set to CG33, to measure the secondary demodulation power. In step S12, the measurement is waited for, and
When the measurement is completed, the measured power p
To get. Since the measured power p is obtained by subjecting a signal addressed to the own station (or another station) to secondary demodulation, the measured power p includes a signal component and has a value corresponding thereto. In step S14, the measured power p is stored in the reference value register P _REF .

Since the processing after step S1 is the same as that in FIG. 6, the same step numbers are assigned and the description is omitted. However, it is determined whether or not the step S15, p <P _REF, p <P running minimum value detection process and the minimum value update processing with Step S6, S7 when the _REF, step S6 otherwise, S7 Skip the process. Therefore, when this process is completed, the code C corresponding to the minimum p among those satisfying p <P _REF is not used, and
Is used as the interference signal power.

[0066] Figure 8 is a flow chart of unused code detection processing according to the third embodiment, the center frequency f 2 primary demodulating power near _c is when below a predetermined threshold value (reference value), the code C (I at that time ) Is determined as an unused code, and the subsequent search is terminated. The processing is basically the same as in FIG. However, if p <P _{REF in} the determination in step S15, the process proceeds to step S7, where p is set in the register P _MIN and the code C
(I) is stored in the memory.

If all the codes are in use, the determination in step S15 is not satisfied, and the process is terminated by satisfying I ≧ N in step S9. Such a state can be identified by P _MIN = p _max .

[0068] Figure 9 is an average value per one in the flow chart of unused code detection process according to the fourth embodiment, the secondary demodulation power in the vicinity of the center frequency f _c is lower than a predetermined reference value, the interference it The case where it is used as signal power is shown.

[0069] At step S21 using code C _i in use in the local station obtains the secondary demodulation power p. Step S ₂₂
Then, p is stored in the reference value register P _REF . Step S
At 23, both index registers I and J are initialized to "0", and the maximum value _pmax is set in the minimum value register _PMIN . In step S24, the code C (I) is obtained from the code table, and in step S25, the code C (I) is obtained.
To measure the secondary demodulated power.

[0070] determines whether step S26 the p <P _REF, in the case of p <P _REF stores p in the table TBL (J) for storing measured power in step S27.
In step S28, +1 is added to J. Step S
If p <P _REF is not satisfied in the determination at step 26, the above step S2
7, the processing of S28 is skipped. In step S29, the value of the register I is incremented by one. In step S30, it is determined whether or not I ≧ N. If I ≧ N, the flow returns to step S24, and the same processing as described above is performed for the next code C (I).
When I ≧ N is determined in step S30, the process proceeds to step S31, where the average value of all the interference signal powers stored in the table TBL is obtained, and the process ends.

In each of the above embodiments, the primary modulation (B
Secondary modulation (spread spectrum) of the signal after PS modulation
And an example in which the signal after secondary demodulation (spectrum despreading) is subjected to primary demodulation (such as BPS demodulation) has been described.
The present invention performs primary modulation (such as BPS modulation) on a signal after secondary modulation (spread spectrum) and primary demodulation (such as BPS demodulation).
The present invention can also be applied to the case where the subsequent signal is subjected to secondary demodulation (spectrum despreading).

Although a plurality of preferred embodiments of the present invention have been described, it is needless to say that various changes can be made in the configuration, control, and combination of these components without departing from the spirit of the present invention. Not even.

[0073]

As described above, according to the present invention, even if the system (or cell) does not reserve a specific spreading code for measuring interference power, the mobile station can detect an unused code by itself, Alternatively, the noise (interference signal) power at the own station can be efficiently measured by being notified from the base station, and this can be effectively used for remote control of transmission power to the base station, diversity combining of the received signal of the own station, and the like. .

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a configuration of a mobile communication system according to an embodiment.

FIG. 3 is a diagram illustrating a communication format of the mobile communication system according to the embodiment.

FIG. 4 is a diagram illustrating a power measurement unit according to the embodiment.

FIG. 5 is a diagram showing a configuration of a secondary demodulation unit according to the embodiment.

FIG. 6 is a flowchart of an unused code detection process according to the first embodiment.

FIG. 7 is a flowchart of an unused code detection process according to the second embodiment.

FIG. 8 is a flowchart of an unused code detection process according to the third embodiment.

FIG. 9 is a flowchart of an unused code detection process according to a fourth embodiment.

FIG. 10 is a diagram (1) for explaining a conventional technique.

FIG. 11 is a diagram (2) explaining a conventional technique.

FIG. 12 is a diagram (3) illustrating a conventional technique.

[Explanation of symbols]

 Reference Signs List 10 mobile station (MS1) 11 speaker (S) 12 microphone (M) 13 baseband processing unit (BBP) 14 codec (CODEC) 15 CDMA control unit 16 primary modulation unit 17 code signal generation unit (CG) 18 secondary modulation Section (code spreading section) 19 attenuator (ATT) 20 D / A converter (D / A) 21 frequency conversion section (FCV) 22 transmission amplifier (TXA) 23 transmission / reception switch (C) 24 antenna 25 RF amplifier ( RFA) 26 Frequency conversion unit (FCV) 27 Synchronization detection unit 28 Code signal generation unit (CG) 29 Secondary demodulation unit (code despreading unit) 30 Primary demodulation unit 31 Terminal control unit 32 Console unit 33 Code signal generation unit ( CG) 34 Power measurement unit 35 Common bus 40 Base station (BS)

Claims (7)

[Claims] 1. A base station and a plurality of mobile stations within its service area are connected by a DS-CDMA system, transmission signals from the base station are spread by mutually orthogonal codes, and all transmission timings are synchronized. A mobile station device of a mobile communication system, comprising: a signal power measuring unit for measuring a signal power near a center frequency of a signal obtained by despreading a received signal of the own station with a designated spreading code; The measurement of each spread code corresponding to the minimum signal power among the obtained signal powers is sequentially determined via the signal power measurement unit to determine that the spread code corresponding to the minimum signal power is not used in the service area. A mobile station device comprising: a control unit. 2. The mobile station apparatus according to claim 1, wherein the measurement control unit sets a signal power that is lower than a predetermined reference value among the obtained signal powers as a minimum value determination target. 3. The mobile station apparatus according to claim 2, wherein the measurement control unit obtains an average value of each signal power lower than a predetermined reference value and uses the average value as an interference signal power of the own station. 4. A base station and a plurality of mobile stations within its service area are connected by a DS-CDMA system, transmission signals from the base station are spread by mutually orthogonal codes, and all transmission timings are synchronized. A mobile station device of a mobile communication system, comprising: a signal power measuring unit for measuring a signal power near a center frequency of a signal obtained by despreading a received signal of the own station with a designated spreading code; The respective signal powers corresponding to the spread codes are sequentially measured via the signal power measurement unit, and the subsequent measurement of the signal power is terminated when the signal power below the predetermined reference value is measured, and the predetermined reference value is changed. A mobile station device, comprising: a measurement control unit that determines that a spreading code corresponding to a signal power lower than that is used in a service area. 5. The predetermined reference value is a value determined based on signal power near a center frequency obtained for a signal obtained by despreading a received signal of the own station with a spreading code used by the own station or another station. The mobile station device according to any one of claims 2 to 4, wherein: 6. A base station and a plurality of mobile stations within its service area are connected by a DS-CDMA system, transmission signals from the base station are spread by mutually orthogonal codes, and all transmission timings are synchronized. In the mobile station device of the mobile communication system, a signal received by the own station is searched for by the own station, or a signal despread with an unused spreading code in a service area notified by the base station, from a signal near its center frequency. A first signal power measuring unit for measuring the first signal power in the above, and a second signal power near the center frequency of a signal obtained by despreading a received signal of the own station with a spreading code used in the own station. A second signal power measuring unit that performs transmission power control information determined based on a desired signal power of the own station obtained by subtracting the first signal power from the second signal power to the base station. A mobile station device comprising: a base station transmission power remote control unit. 7. A base station and a plurality of mobile stations within its service area are connected by a DS-CDMA system, transmission signals from the base station are spread by mutually orthogonal codes, and all transmission timings are synchronized. In the mobile station device of the mobile communication system, a signal received by the own station is searched for by the own station or a signal despread with an unused spreading code in a service area notified by the base station from a signal near its center frequency. A first signal power measuring unit for measuring the first signal power in the above, and measuring a second signal power near the center frequency from a signal obtained by despreading a received signal of the own station with a spreading code used in the own station. A second signal power measuring unit that performs the diversity combining of the received signals of the own station based on the first and second signal powers, and performs a diversity combining. A mobile station device comprising: