JP2000224104A - Mobile radio communication terminal, mobile communication system and radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly dudge communication quality, even when transmission power control is adopted by providing a communication quality value calculating means for calculating communication quality value based on the maximum transmission possible power value, transmission power value and reception power value. SOLUTION: The received power value of a required channel in a receiver 12a is detected by a reception power value detecting part 12d, and the detection value is given to a mobile terminal control unit 16. A mobile terminal control unit 16 controls the operations of a communication unit 12 and a signal processing unit 13 and also exchanges control data with a radio base station. A communication quality value calculating means 16a is included as a control means provided with the unit 16, in addition to general means for designating an exchange frequency concerning the receiver 12b and a transmission 12c and for controlling call connection or the like. The means 16a calculates the communication quality value by considering how much margin exists between the present transmission power value and the maximum transmission possible power value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile radio communication terminal, a mobile communication system, and a radio base station for performing communication via a radio channel, and more particularly to a communication quality evaluation function.

[0002]

2. Description of the Related Art In mobile communication, the reception level of a radio channel greatly fluctuates with time as a terminal moves. Generally, fading occurs due to interference of so-called multiplex waves passing through a plurality of paths. Also,
Produced by shielding radio waves by buildings, etc.
There is a variation called so-called shadowing. Further, the average reception level varies according to the distance between the base station and the terminal. And, as described above, when the reception level fluctuates greatly, the communication quality also fluctuates.

It is important for a user of a mobile radio communication terminal to know whether communication with good quality is possible before starting communication or during communication.

That is, when the communication quality is not good,
The caller may be inconvenienced by poor quality, so if the caller is an important caller, communication may be attempted after the quality is restored, or conversely, calls to family members, etc. Then, even if the quality is poor, it is conceivable to make a call regardless of the willingness to do so.

[0005] Further, in the case of data communication, if the quality deteriorates during the communication and the line is disconnected, the data communication will not be completed. If the quality is not good, the start of the data communication may be postponed. Can be

As described above, quality display to the user is an important issue.

Therefore, conventionally, in a portable telephone or the like, the communication quality is detected and displayed based on the level of the average reception level within a predetermined time. This quality indication, of course, represents the current actual communication quality, but is also effective in determining how much the quality may be degraded due to a change in the reception level after the start of communication.

[0008] It is important for the system to grasp the communication quality in addition to displaying the communication quality to the user.

That is, at the start of communication, the quality is measured and measured.
It is necessary to detect and determine whether the quality is communicable. If the quality cannot satisfy the specified value, it is necessary to reject the call connection. Further, if the quality is significantly deteriorated during communication, it is impossible to continue the communication any more, so it is necessary to forcibly disconnect the call. In any of these cases, accurate detection of communication quality is required.

On the other hand, the communication quality during standby is detected based on the reception level of the control signal.

[0011] That is, in order to control and provide information to a waiting terminal, a control signal normally transmitted at a constant power through a control channel to which a dedicated spreading code is allocated in the CDMA system is set. It receives and determines the serving cell. Therefore, there has been a method of detecting and displaying the communication quality in the terminal in standby mode by receiving the control signal, detecting the reception level thereof, and performing the detection in accordance with the magnitude.

Alternatively, in a slightly advanced system, the interference level at the terminal is measured in the same manner as the base station, and the signal-to-interference wave power ratio (CI
R), and the communication quality is detected and displayed based on the result.

However, generally, the quality of base reception (uplink) is lower than that of terminal reception (downlink). For this reason, originally, the communication quality should be detected and displayed based on the reception level at the wireless base station.

By the way, in mobile communication, especially in a system called a cellular system, so-called transmission power control for controlling transmission power to a necessary minimum value may be adopted in order to reduce co-frequency interference.

In the CDMA (code division multiple access) mobile communication system, in order to solve the so-called near-far problem, the transmission level of the terminal is controlled so that the reception level at the base station becomes a constant value. In a more advanced system, there is a method of measuring the interference level at the base station and controlling the transmission power of the terminal so that the signal-to-interference-wave power ratio becomes a constant value.

When implementing such transmission power control,
There are so-called open-loop control for controlling transmission power according to the level of its own reception level, and so-called closed-loop control for controlling transmission power according to the level of reception at the partner station. In any case, the maximum transmittable power is absolutely limited by the characteristics of the wireless device of the terminal. Further, there is a case where the maximum transmittable power is specified for each cell from the control of the cell size and the consideration of interference with other cells. In some cases, the maximum transmittable power is determined for each type of terminal such as a portable device or a vehicle-mounted device.

When such transmission power control is performed,
If the transmission power control operates ideally, the reception level at the radio base station is always a constant value, so that the reception level at the radio base station cannot accurately represent the communication quality.

[0018]

As described above, conventionally,
Since the communication quality in the mobile radio communication terminal has been determined based on its own reception level, it has not taken into account the communication quality in the worse condition uplink channel,
The correct communication quality could not be determined.

Therefore, it is conceivable to determine the communication quality based on the reception level at the radio base station. However, in the case of a system that performs transmission power control, the reception level at the radio base station is controlled to be constant. There was a problem that the quality could not be determined.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a mobile radio communication system capable of correctly determining communication quality even when transmission power control is employed. A terminal, a mobile communication system, and a wireless base station are provided.

[0021]

According to the present invention, when performing transmission power control, the communication quality can be kept constant as long as the transmission power can be changed. The amount of margin between the power value and the maximum transmittable power value indicates the difficulty of quality degradation, and is considered to be a communication quality value that matches the user's feeling, and communication based on such information is considered. This is to determine the quality.

Based on such a concept, the present invention changes the transmission power within a range not exceeding a predetermined maximum transmittable power value according to the reception power value of the radio signal transmitted from the radio base station. The mobile radio communication terminal includes a communication quality value calculating unit that calculates a communication quality value based on the maximum transmittable power value, the transmission power value, and the reception power value.

[0023] Also, the present invention provides a mobile radio communication terminal, wherein the radio base station transmits predetermined notification information relating to a power difference between a received power value relating to a radio signal transmitted from the mobile radio communication terminal and a predetermined set received power value. Used in a mobile communication system in which the mobile radio communication terminal changes a transmission power value within a range not exceeding a predetermined maximum transmittable power value according to the power difference determined based on the notification information. In the mobile radio communication terminal to be determined, the received power value at the radio base station is determined based on the notification information, and a communication quality value is calculated based on the received power value, the maximum transmittable power value, and the transmission power value. Communication quality value calculating means.

Further, according to the present invention, the radio base station transmits predetermined notification information relating to a power difference between a received power value relating to a radio signal transmitted from a mobile radio communication terminal and a predetermined set received power value to the mobile station. Notify the wireless communication terminal, and the mobile wireless communication terminal, the transmission power value, according to the power difference determined based on the notification information, the received power value in a range not exceeding a predetermined maximum transmittable power value In a mobile radio communication terminal used in a mobile communication system that changes the received power value to the set received power value, a communication quality value calculation unit that calculates a communication quality value based on the maximum transmittable power value and the transmission power value. Equipped.

According to the present invention, the mobile radio communication terminal can perform mobile communication by transmitting and receiving a spread spectrum modulated radio signal between the radio base station and the mobile radio communication terminal. A radio base station notifies the mobile radio communication terminal of predetermined notification information related to a signal-to-interference-wave power ratio of a radio signal transmitted from the mobile radio communication terminal, and the mobile radio communication terminal has a transmission power value. In the mobile radio communication terminal used in a mobile communication system that changes within a range not exceeding a predetermined maximum transmittable power value according to the signal-to-interference wave power ratio determined based on the notification information, The signal-to-interference wave power ratio is determined based on information, and a communication quality value is calculated based on the signal-to-interference wave power ratio, the maximum transmittable power value, and the transmission power value. With a quality value calculation means.

By taking the means of each of the above inventions,
A more appropriate communication quality value is calculated in consideration of the ratio between the maximum transmittable power value and the transmission power value, which is information indicating the difficulty of quality degradation.

According to the present invention, there is provided a mobile radio communication terminal for changing transmission power within a range not exceeding a predetermined maximum transmittable power value according to a reception power value of a radio signal transmitted from a radio base station. A control channel power value measuring means for measuring a reception power value of a control channel transmitted from the radio base station; and a reception power value measured by the control channel power value measurement means and a maximum value of the mobile radio communication terminal. Communication quality value calculating means for calculating a communication quality value based on the transmittable power value.

According to the present invention, there is provided a mobile communication system which enables mobile communication by the mobile radio communication terminal by transmitting and receiving a spread spectrum modulated radio signal between the radio base station and the mobile radio communication terminal. The radio base station includes: a total reception power value measuring unit for measuring a total reception power value for all radio bands allocated to the radio base station; and a control channel for transmitting the total reception power value measured by the total reception power value measurement unit. The mobile radio communication terminal further comprises: a control channel power value measurement unit that measures a reception power value related to the control channel. The received power value measured by the control channel power value measuring means, the maximum transmittable power value of the mobile radio communication terminal, and the total value reported on the control channel. Equipped with a communication quality value calculating means for calculating a communication quality value based on the transmission power value.

By taking the means of these two inventions, the ratio between the transmittable power value and the transmit power value cannot be obtained because no transmission is performed during standby.
The magnitude of the transmittable power value is the magnitude of the variable range of the transmit power value, which is information indicating the likelihood of quality degradation when communication is started. By taking this into account, a more appropriate communication quality value can be obtained. Is calculated.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a main configuration of a mobile radio communication terminal according to the present embodiment.

This mobile radio communication terminal has an antenna 11,
Communication unit 12, signal processing unit 13, operation unit 1
4, a display unit 15 and a mobile terminal control unit 16.

The communication unit 12 has a duplexer (DU)
P) 12a, a receiver 12b, a transmitter 12c, and a received power value detector 12d.

The radio signal received by the antenna 11 is separated by the duplexer 12a, input to the receiver 12b, and demodulated. The signal demodulated by the receiver 12b is input to the signal processing unit 13.

The signal processing unit 13 is a well-known device for implementing any of various communication functions such as a telephone function, an interface function of a facsimile terminal, and an interface function of a data communication terminal such as a personal computer. Perform processing.

The signal output from the signal processing unit 13 is provided to a transmitter 12c and modulated to be a radio signal. The wireless signal is supplied to the antenna 11 via the duplexer 12a and transmitted.

The received power value detector 12d detects the received power value of the required channel at the receiver 12b, and the detected value is given to the mobile terminal control unit 16.

The operation unit 14 includes, for example, a key group, a touch panel, and the like, and receives various instruction inputs from the user to the mobile terminal control unit 16.

The display unit 15 has, for example, a liquid crystal display, and performs a display for notifying the user of various information under the control of the mobile terminal control unit 16.

The mobile terminal control unit 16 controls the operation of the communication unit 12 and the signal processing unit 13, and realizes the operation as a mobile radio communication terminal by exchanging control data with a radio base station. .

The mobile terminal control unit 16 is mainly composed of a microcomputer, for example, and realizes various control means by software processing. The control means of the mobile terminal control unit 16 includes, for example, a communication quality value in addition to well-known general means such as designation of a transmission / reception frequency for the receiver 12b and the transmitter 12c and call connection control. Calculation means 16a
Contains.

The communication quality value calculating means 16a calculates the communication quality value in consideration of the margin between the current transmission power value and the maximum transmittable power value by several methods described later. Perform the calculation.

(First Embodiment) The operation of the mobile radio communication terminal having the above-described configuration according to the first embodiment of the present invention will be described below.

The operation of the mobile radio communication terminal according to the present embodiment is characterized by the process of calculating the communication quality value, and the other processes are the same as those of the known mobile radio communication terminal. The transmission power control processing including the processing will be described.

The mobile terminal control unit 16 repeatedly executes a transmission power control process as shown in FIG. 2 at a predetermined cycle when a communication path is established and in a communication state.

In the transmission power control process, the mobile terminal control unit 16 first receives the reception power value R [dB] detected by the reception power value detection unit 12d, that is, the reception related to the traffic channel allocated to the mobile radio communication terminal. The power value R is taken in (step ST1).

Subsequently, the mobile terminal control unit 16 adds a transmission power correction value obtained as a difference (R−Rs) from a predetermined set value Rs [dB] to the current transmission power value T [W]. Is determined to be not less than the maximum transmittable power value Tm [W] (step ST2).

Here, if T + (R−Rs) is lower than the maximum transmittable power value Tm, the transmission power correction value (R
-Rs), even if the transmission power value T is corrected as it is, the corrected transmission power value does not exceed the maximum transmittable power value Tm.
Is changed to a value obtained by adding the transmission power correction value (R-Rs) to the current transmission power value T (step ST3).

However, if T + (R−Rs) becomes equal to or more than the maximum transmittable power value Tm, the transmission power value T is directly corrected by the transmission power correction value (R−Rs), and the corrected transmission power value becomes Since the maximum transmittable power value Tm is equal to or greater than the maximum transmittable power value Tm, the mobile terminal control unit 16 sets the transmitter 12 to change the transmit power value T to the maximum transmittable power value Tm.
c (step ST4).

When the change of the transmission power value T is completed as described above, the mobile terminal control unit 16
Calculates the communication quality value by the communication quality value calculation means 16a according to the formula of R + 10 × log (Tm / T) (step ST
5).

Then, the mobile terminal control unit 16 displays the communication quality displayed on the display unit 15 in step ST5.
Is updated to match the newly calculated communication quality value (step ST6).

The communication quality is displayed by displaying an image indicating the ratio of the communication quality value to the communication quality value range, for example, as indicated by reference numeral I in FIG.

Thus, according to the present embodiment, both the received power value R as the communication quality of the downlink channel and the ratio of the maximum transmittable power value Tm and the transmission power value T as the communication quality of the uplink channel are considered. Since the communication quality value is calculated by the calculation, it is possible to obtain an appropriate communication quality value that enables more accurate determination of whether or not the state is suitable for performing communication.

In this embodiment, the communication quality value can be calculated from the values that can be obtained by the mobile radio communication terminal alone, such as the received power value R, the transmitted power value T, and the maximum transmittable power value Tm. It is suitable for a mobile communication system that performs transmission frequency control by control.

In this embodiment, transmission power control is performed to determine its own transmission power value T based on the reception power value R.
When the frequencies of transmission and reception (uplink channel and downlink channel) are distant, the correlation between the propagation loss values of the uplink channel and downlink channel as seen instantaneously decreases, and thus the error in transmission power control increases. However, it is effective in a TDD (Time Division Duplex) system in which transmission and reception are performed in the same frequency by time division.

Further, in the case of wideband signal transmission, Rayleigh fading which has occurred in the case of narrowband transmission is eliminated, and instantaneous fluctuation itself is greatly reduced.

(Second Embodiment) Hereinafter, the operation of the mobile radio communication terminal having the above-described configuration according to the second embodiment of the present invention will be described.

The operation of the mobile radio communication terminal according to the present embodiment is characterized by a process of calculating a communication quality value, and the other processes are the same as those of a known mobile radio communication terminal. The transmission power control processing including the processing will be described.

Also, the present invention provides a mobile communication system in which a radio base station notifies a mobile radio communication terminal of a transmission power control amount so that its reception level becomes constant, and performs transmission power control by closed loop control. Shall apply.

That is, the radio base station of the mobile communication system using the mobile radio communication terminal of the present embodiment measures the individual received power values Rbs [dB] of the channels under its control. Then, a difference ΔR from a preset reception power set value Rbss [dB] = Rbs−Rbss [d
B] is calculated, and this ΔR is notified as a transmission power control amount to the mobile radio communication terminal to which each channel is assigned.

The transmission power control amount ΔR is notified from the radio base station to the mobile radio communication terminal while being included in the control signal.

That is, for example, in the case of the three-channel TDMA system, the time slots TS11, TS21, TS31,... Of each channel are set in order as shown in FIG. In each time slot, a frame synchronization signal F, a control signal C, and a communication signal S such as coded voice are inserted. Therefore, the transmission power control amount ΔR is shown in the control signal C in the time slot allocated to the mobile radio communication terminal of the notification destination. In the present embodiment, the radio base station also indicates the received power value Rbs in the control signal C and notifies the mobile radio communication terminal.

When the communication path has been established and the mobile terminal is in the communication state, the mobile terminal control unit 16 repeatedly executes the transmission power control processing as shown in FIG. 5 at a predetermined cycle.

In the transmission power control process, the mobile terminal control unit 16 first recognizes the control channel and determines the transmission power control amount ΔR and the received power value Rbs notified from the radio base station as described above (step ST1).
1).

Subsequently, the mobile terminal control unit 16 calculates the value obtained by adding the transmission power control amount ΔR to the current transmission power value T,
It is determined whether or not the maximum transmittable power value Tm or more is reached (step ST12).

Here, T + ΔR is the maximum transmittable power value T
m, if the transmission power value T is directly modified by the transmission power control amount ΔR, the corrected transmission power value does not exceed the maximum transmittable power value Tm. 16 instructs the transmitter 12c to change the transmission power value T to a value obtained by adding the transmission power control amount ΔR to the current transmission power value T (step ST13).

However, if T + (R−Rs) is equal to or greater than the maximum transmittable power value Tm, the transmission power control amount Δ
If the transmission power value T is corrected as it is in R, the corrected transmission power value becomes greater than or equal to the maximum transmittable power value Tm. Therefore, the mobile terminal control unit 16 changes the transmission power value T to the maximum transmittable power value Tm. It instructs the transmitter 12c to do so (step ST14).

When the transmission power value T has been changed as described above, the mobile terminal control unit 16
Calculates the communication quality value by the communication quality value calculation means 16a according to the formula of Rbs + 10 × log (Tm / T) (step ST1).
5).

Then, the mobile terminal control unit 16 displays the communication quality displayed on the display unit 15 in step ST5.
Is updated to match the newly calculated communication quality value (step ST16).

Thus, according to the present embodiment, the communication quality value is calculated in consideration of both the received power value Rbs at the radio base station and the ratio between the maximum transmittable power value Tm and the transmit power value T. It is possible to obtain an appropriate communication quality value that enables more accurate determination of whether the state is suitable for performing communication.

Further, according to the present embodiment, since the received power value Rbs at the radio base station is taken into consideration, even in a system in which the received power set value Rbss is changed according to, for example, traffic congestion, etc. It is possible to always obtain an appropriate communication quality value.

(Third Embodiment) In the above-described second embodiment, the reception power value Rbs at the radio base station is considered in order to adapt to the case where the reception power setting value Rbss fluctuates. In the case of a mobile radio communication terminal used in a mobile communication system in which the reception power setting value Rbss is unchanged, the reception power value Rbs is controlled to be constant and can be ignored.

Hereinafter, an embodiment in which the received power value Rbs is not used for calculating the communication quality value will be described.

In this case, the radio base station notifies the mobile radio communication terminal of the control signal by including only the transmission power control amount ΔR, and does not report the received power value Rbs.

When the communication path is established and the mobile terminal control unit 16 is in the communication state, the mobile terminal control unit 16 repeatedly executes the transmission power control processing as shown in FIG. 6 at a predetermined cycle.

In the transmission power control process, the mobile terminal control unit 16 first recognizes the control channel and determines the transmission power control amount ΔR notified from the radio base station as described above (step ST21).

Subsequently, the mobile terminal control unit 16 calculates the value obtained by adding the transmission power control amount ΔR to the current transmission power value T,
It is determined whether or not the maximum transmittable power value Tm or more is reached (step ST22).

Here, T + ΔR is the maximum transmittable power value T
m, if the transmission power value T is directly modified by the transmission power control amount ΔR, the corrected transmission power value does not exceed the maximum transmittable power value Tm. 16 instructs the transmitter 12c to change the transmission power value T to a value obtained by adding the transmission power control amount ΔR to the current transmission power value T (step ST23).

However, if T + (R−Rs) is equal to or more than the maximum transmittable power value Tm, the transmission power control amount Δ
If the transmission power value T is corrected as it is in R, the corrected transmission power value becomes greater than or equal to the maximum transmittable power value Tm. Therefore, the mobile terminal control unit 16 changes the transmission power value T to the maximum transmittable power value Tm. Instruct the transmitter 12c to do so (step ST24).

When the change of the transmission power value T is completed as described above, the mobile terminal control unit 16
Calculates the communication quality value from the communication quality value calculation means 16a by the formula of 10 × log (Tm / T) (step ST2).
5).

Then, the mobile terminal control unit 16 displays the communication quality displayed on the display unit 15 in step ST2.
The communication quality value is updated to match the newly calculated communication quality value in step 5 (step ST26).

(Fourth Embodiment) The operation of the mobile radio communication terminal having the above-described configuration according to the fourth embodiment of the present invention will be described below.

The operation of the mobile radio communication terminal according to the present embodiment is characterized by a process of calculating a communication quality value, and other processes are the same as those of a known mobile radio communication terminal. The transmission power control processing including the processing will be described.

Further, according to the present invention, a CDMA system is used as a multiple access system in a radio line, and a radio base station uses a CIR (signal-to-interference-wave power ratio) of each mobile radio communication terminal during communication for each mobile radio communication terminal. To the mobile communication system that performs transmission power control by closed-loop control based on the CIR.

That is, the radio base station of the mobile communication system using the mobile radio communication terminal of the present embodiment has a configuration as shown in FIG.

As shown in this figure, the radio base station includes an antenna 21, a duplexer (DUP) 22, and a receiver 23 (23-1).
To 23-n), a transmitter 24 (24-1 to 24-n), a control signal transceiver 25, a power detection unit 26, and a base station control unit 2.
7.

[0086] The mobile radio communication terminal transmits and arrives,
The radio signal received by the antenna 21 is transmitted to the duplexer 22
Is input to each of the n receivers 23 (23-1 to 23-n), the control signal transceiver 25, and the power detector 26.

The receiver 23 has a despreading circuit 23a, a spreading code generating circuit 23b and a signal level detecting circuit 23c as shown in FIG.

The radio signal provided from the duplexer 22 is input to the despreading circuit 23a. Despreading circuit 2
3a, a spreading code for a traffic channel corresponding to the receiver 23 generated by the spreading code generating circuit 23b is given. Therefore, the despreading circuit 23a despreads the radio signal using the spreading code given from the spreading code generating circuit 23b, and returns to a baseband code. The baseband code obtained by the receiver 23 is transferred to the exchange via the base station control unit 27.

The signal level detection circuit 23c, based on the output from the despreading circuit 23a, receives the reception power value Lm for the traffic channel corresponding to the receiver 23.
(S) is detected, and this is notified to the base station control unit 27.

On the other hand, the signal provided from the exchange to the mobile radio communication terminal is supplied by the base station control unit 27 to the transmitter 24 corresponding to the traffic channel assigned to each destination mobile radio communication terminal.

The transmitter 24 spreads the signal provided from the base station control unit 27 using the spreading code of the traffic channel corresponding to the signal, and converts the signal into a radio signal of a frequency band for a downlink channel.

[0093] The radio signal obtained by the transmitter 24 is supplied to the antenna 21 via the duplexer 22 and transmitted to the mobile radio communication terminal.

The control signal transceiver 25 is a duplexer
2 is despread using the spreading code of the control channel to return to the baseband code. Then, the baseband code obtained by the control signal transceiver 25 is
It is provided to the base station control unit 27.

The power detection unit 26 detects the total received power value Lm (i) for the uplink channel and notifies the base station control unit 27 of it.

The base station control unit 27 controls the operation of each unit constituting the radio base station, and exchanges control data with mobile radio communication terminals and exchanges to operate as a radio base station. Realize. The base station control unit 27 mainly includes, for example, a microcomputer, and realizes various control means by software processing.

The base station control unit 27 also has an interface function for exchanging signals with the exchange.

Now, the total received power value Lm (i) detected by the power detection unit 26 is the sum of the signal from the target mobile radio communication terminal and the signal (interference signal) from the non-target mobile radio communication terminal. This is the received power value. Since the transmission power of the signal from the mobile radio communication terminal is controlled, if the signal level from one mobile radio communication terminal is L and the number of terminals transmitting simultaneously is k, Lm (i) = k × L + N. N is another noise / interference component.

By the way, the despread signal includes, in addition to the signal from the target mobile radio communication terminal, interference from a non-target mobile radio communication terminal or the like without being despread. Assuming that the level of the target signal after despreading is Ls and the level of the interference wave component is Li, Ls is obtained by despreading L, and the power is directly used as baseband power. That is, Ls = L.

On the other hand, since the interference wave component is not despread, the spread band remains as it is, and after passing through the baseband filter, the power is the spread gain, that is, the chip rate Bc [cps] of the spread code is equal to the bit rate of the baseband code. It is reduced to the reciprocal multiple of the value obtained by dividing by Bb [bps].

That is, Li = {(k−1) × L + N} × (Bb / Bc).

The signal-to-interference wave power ratio CIR is as follows: CIR = Ls / Li = (Bc / Bb) / {(k−1) + N / L}

Lm (s) is the sum of the power of Ls and Li. In a normal case where good communication is possible, Ls> Li, and Lm (s) ≒ Ls can be approximated. In the case of a normal CDMA mobile communication system having a spread bandwidth of 1 MHz or more, k is a number of 10 or more.
k-1 と k.

Therefore, Lm (s) / Lm (i) = (Ls + Li) / (k × L + N) {L / {(k−1) × L + N)}. Therefore, (Lm (s) / Lm (i)) × (Bc / Bb) {(Bc / Bb) / {(k−1) + N / L}, and Lm (s) / Lm (i) × (Bc / Bb) approximately equals the CIR.

Therefore, the base station control unit 27 determines the total received power Lm (i) detected by the power detector 26.
And the received power value Lm of each traffic channel detected by the signal level detection circuit 23c of each receiver 23, respectively.
From (s), the CIR is calculated for each traffic channel by the above equation. And the base station control unit 27
Causes the control signal transceiver 25 to transmit the calculated CIR in a control signal addressed to each mobile radio communication terminal.

Now, in the mobile radio communication terminal, the mobile terminal control unit 16 repeatedly executes a transmission power control process as shown in FIG. 9 at a predetermined cycle when a communication path is established and in a communication state.

In this transmission power control process, the mobile terminal control unit 16 first recognizes a control signal arriving via the control channel and directed to its own terminal, and determines the CIR notified from the radio base station as described above ( Step ST3
1).

Subsequently, the mobile terminal control unit 16 sets the CI
A transmission power correction value ΔT required to set R to a predetermined required minimum value is calculated (step ST32).
Then, the mobile terminal control unit 16 determines whether or not a value obtained by adding the calculated transmission power correction value ΔT to the current transmission power value T [W] is equal to or greater than the maximum transmittable power value Tm [W]. (Step ST33).

Here, T + ΔT is the maximum transmittable power value T
m, if the transmission power value T is corrected as it is with the transmission power correction value ΔT, the corrected transmission power value does not exceed the maximum transmittable power value Tm. 16 instructs the transmitter 12c to change the transmission power value T to a value obtained by adding the transmission power correction value ΔT to the current transmission power value T (step ST34).

However, if T + ΔT is equal to or greater than the maximum transmittable power value Tm, if the transmit power value T is directly modified with the transmit power correction value ΔT, the corrected transmit power value becomes equal to or greater than the maximum transmittable power value Tm. Therefore, the mobile terminal control unit 16 instructs the transmitter 12c to change the transmission power value T to the maximum transmittable power value Tm (step ST35).

When the change of the transmission power value T is completed as described above, the mobile terminal control unit 16
Calculates the communication quality value by the communication quality value calculation means 16a by the formula of 10 × log (CIR) + 10 × log (Tm / T) (step ST3).
6).

Then, the mobile terminal control unit 16 displays the communication quality displayed on the display unit 15 in step ST3.
The communication quality is updated to match the newly calculated communication quality value in step 6 (step ST37).

Thus, according to the present embodiment, the communication quality value is calculated by taking into account both the signal-to-interference-wave power ratio CIR at the radio base station and the ratio between the maximum transmittable power value Tm and the transmit power value T. Therefore, it is possible to obtain an appropriate communication quality value that can more accurately determine whether or not the state is suitable for performing communication.

(Fifth Embodiment) In each of the above embodiments, only the communication quality value in the communication state can be calculated.

Therefore, an embodiment for calculating the communication quality value during standby will be described below.

When in the standby state, the mobile terminal control unit 16 repeatedly executes a communication quality value display process as shown in FIG. 10 at a predetermined cycle.

In the communication quality value display process, the mobile terminal control unit 16 first receives the control power from the control channel, while the receiver 12b receives the control channel. The power value Rc [dB] is captured (step ST41).

Subsequently, the mobile terminal control unit 16 calculates the communication quality value by the communication quality value calculation means 16a by the formula of 10 × log (Rc) + 10 × log (Tm) (step ST4).
2).

Then, the mobile terminal control unit 16 displays the communication quality displayed on the display unit 15 in step ST4.
The communication quality is updated to match the newly calculated communication quality value in step 2 (step ST43).

Thus, according to the present embodiment, the communication quality value is calculated in consideration of both the received power value Rc as the communication quality of the downlink channel and the maximum transmittable power value Tm as the communication quality of the uplink channel. In addition, it is possible to obtain an appropriate communication quality value that can more accurately determine whether or not the state is suitable for performing communication.

Note that the maximum transmittable power value Tm is not information that directly indicates communication quality, but is a value that indicates a control range of the transmit power value T after starting communication, and therefore has a large value. The better the communication quality is, the longer the possibility of maintaining good communication quality is, and it can be said that it represents the communication quality as a margin until the communication quality deteriorates.

(Sixth Embodiment) In the fifth embodiment, the communication quality value is calculated based on a value that can be independently obtained by the mobile radio communication terminal. The communication quality value is calculated in consideration of the reception situation at the station, and is realized by a mobile communication system including a mobile radio communication terminal having the configuration shown in FIG. 1 and a radio base station as shown in FIG.

FIG. 11 is a block diagram showing a main configuration of a radio base station according to this embodiment. The same parts as those in FIG. 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in this figure, the radio base station comprises an antenna 21, a duplexer (DUP) 22, and a receiver 23 (23-1).
To 23-n), a transmitter 24 (24-1 to 24-n), a control signal transceiver 25, a power detection unit 26, and a base station control unit 2.
Eight.

That is, the radio base station according to the present embodiment is provided with a base station control unit 28 instead of the base station control unit 27 in the general radio base station shown in FIG.

The base station control unit 28 controls the operation of each unit constituting the radio base station, and transmits and receives control data to and from a mobile radio communication terminal and an exchange, thereby operating as a radio base station. Realize. The base station control unit 28 also has an interface function for exchanging signals with the exchange.

The base station control unit 28 is mainly composed of, for example, a microcomputer.
Various control means are realized by software processing.
The control means of the base station control unit 28 includes a control means for realizing a well-known general function in the radio base station and a total received power value notifying means 28a.
have.

The total received power value notifying means 28a performs a process of notifying the standby mobile radio communication terminal of the total received power value Lm (i) detected by the power detector 26 via the control channel.

Now, in the radio base station having such a configuration,
The base station control unit 28 transmits the total received power value informing means 28a.
Thus, the entire received power value notification processing as shown in FIG. 12 is repeatedly executed at a predetermined cycle.

In the total received power value notifying process, first, the base station control unit 28 fetches the total received power value Lm (i) detected by the power detector 26 (step ST).
51).

Then, the base station control unit 28 includes the total received power value Lm (i) fetched in step ST51 in a control signal common to each mobile radio communication terminal, and causes the control signal transceiver 25 to transmit it (step ST51). ST52).

On the other hand, when the mobile terminal control unit 16 in the mobile radio communication terminal is in the standby state,
The communication quality value display processing shown in FIG.

In the communication quality value display processing, the mobile terminal control unit 16 first recognizes a control signal common to each mobile radio communication terminal arriving via the control channel, and is notified from the radio base station as described above. Total received power value Lm
(I) is determined (step ST61).

Subsequently, the mobile terminal control unit 16 fetches the received power value detected by the received power value detector 12d while the receiver 12b receives the control channel, that is, the received power value Rc related to the control channel (see FIG. 4). Step ST62).

Subsequently, the mobile terminal control unit 16 The communication quality value is calculated by the following equation (step ST6).
3).

Then, the mobile terminal control unit 16 displays the communication quality displayed on the display unit 15 in step ST6.
The communication quality is updated to match the communication quality value newly calculated in step 3 (step ST64).

Thus, according to the present embodiment, the communication quality value is calculated in consideration of the total received power value Lm (i) at the radio base station. Here, for the mobile radio communication terminal in the standby state, all radio signals transmitted by other mobile radio communication terminals that are currently communicating become interference waves when transmission starts.

As described in the fourth embodiment, in the CDMA mobile communication system, the transmission power value T of the mobile radio communication terminal is determined by the CIR according to the level of the interference wave in the reception at the radio base station. Determined to be satisfied. This means that the uplink communication quality is not only the control channel reception level at the waiting mobile radio communication terminal,
This means that it largely depends on the interference level at the radio base station.

Therefore, by taking into account the total received power value Lm (i), that is, the interference level when starting communication, as in the present embodiment, it is determined whether or not the state is suitable for communication. It is possible to obtain an appropriate communication quality value that makes it possible to make a more accurate determination.

The present invention is not limited to the above embodiments. For example, in each of the above-described embodiments, the calculated communication quality value is used for notification to the user. However, the communication quality value can be used for another purpose such as control of outgoing / incoming calls or control of forced disconnection of communication. . Note that the calculation timing of the communication quality value is not limited to being repeatedly performed at predetermined intervals as in the above-described embodiments, and the communication quality value is calculated at a timing required for each application according to the application of the communication quality value. The quality value may be calculated.

Further, the equation for calculating the communication quality value is not limited to the one described in each of the above embodiments, and may be changed, for example, by arbitrarily multiplying by a coefficient as needed.

In the second embodiment, the transmission power control amount ΔR and the received power value Rbs are notified from the radio base station to the mobile radio communication terminal. The mobile radio communication terminal may notify the Rbss to calculate the received power value Rbs, or the mobile radio communication terminal may notify the received power value Rbs and the received power set value Rbss to calculate the transmission power control amount ΔR. good. Note that the reception power set value Rbss
Is a common value for each mobile radio communication terminal, so it is not necessary to individually notify the received power set value Rbss, and the received power set value Rbss can be reported collectively using a common control channel or the like.

In the fourth embodiment, the CIR is obtained by the radio base station and notified to the mobile radio communication terminal. However, since the chip rate Bc and bit rate Bb are known in the mobile radio communication terminal, Lm (S) and Lm
(I) from the radio base station to the mobile radio communication terminal,
The CIR may be calculated by the mobile radio communication terminal.

In addition, various modifications can be made without departing from the gist of the present invention.

[0145]

According to the present invention, during communication in a mobile radio communication terminal, the ratio between the current transmission power value and the maximum transmittable power value is taken into account, and further, according to the applied mobile communication system,
The communication quality value is calculated by taking into account the received power value measured by the terminal itself and the signal-to-interference-wave power ratio detected and notified by the radio base station as necessary.

When the mobile radio communication terminal is in standby mode, the maximum transmittable power value is taken into account, and the received power value of the control channel measured by the terminal itself or detected by the radio base station according to the applied system. The communication quality value is calculated by taking into account the total received power value notified as required.

Thus, even when the transmission power control is employed, it is possible to correctly determine the communication quality. Then, it is possible to appropriately determine whether or not communication by the user is possible, based on the appropriate communication quality suitable for the user's feeling. In addition, even when the communication availability is automatically determined, it is possible to make a determination according to the user's feeling, and it is possible to prevent the user from feeling uncomfortable.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a mobile radio communication terminal according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of transmission power control processing executed by the mobile terminal control unit 16 in the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of a communication quality display.

FIG. 4 is a diagram showing an example of a time slot arrangement in the case of a three-channel TDMA system.

FIG. 5 is a flowchart showing a procedure of a transmission power control process executed by a mobile terminal control unit 16 according to the second embodiment of the present invention.

FIG. 6 is a flowchart showing a procedure of a transmission power control process executed by a mobile terminal control unit 16 according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration example of a main part of a radio base station used in a mobile communication system that controls a CIR to a required minimum value by a closed loop.

FIG. 8 is a block diagram showing a main configuration of a receiver 23 in FIG. 7;

FIG. 9 is a flowchart showing a processing procedure of transmission power control processing executed by the mobile terminal control unit 16 in the fourth embodiment of the present invention.

FIG. 10 is a flowchart showing a processing procedure of communication quality value display processing executed by the mobile terminal control unit 16 according to the fifth embodiment of the present invention.

FIG. 11 is a block diagram showing a main configuration of a radio base station included in a mobile communication system according to a sixth embodiment of the present invention.

FIG. 12 is a flowchart showing a processing procedure of a total received power value notification process executed by a base station control unit in a sixth embodiment of the present invention.

FIG. 13 is a flowchart showing a processing procedure of a communication quality value display process executed by the mobile terminal control unit 16 in the sixth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 antenna 12 communication unit 12a duplexer (DUP) 12b receiver 12c transmitter 12d received power detection unit 13 signal processing unit 14 operation unit 15 display unit 16 mobile terminal control unit 16a ... Communication quality value calculation means 21 ... Antenna 22 ... Duplexer (DUP) 23 (23-1 to 23-n) ... Receiver 23a ... Despreading circuit 23b ... Spreading code generation circuit 23c ... Signal level detection circuit 24 (24 -1 to 24-n) transmitter 25 control signal transmitter / receiver 26 power detector 27, 28 base station control unit 28a total received power value notification means

Claims (8)

[Claims] 1. A mobile radio communication terminal for changing transmission power within a range not exceeding a predetermined maximum transmittable power value according to a received power value of a radio signal transmitted from a radio base station, A mobile radio communication terminal, comprising: a communication quality value calculation unit that calculates a communication quality value based on a power value, a transmission power value, and the reception power value. 2. A radio base station notifies said mobile radio communication terminal of predetermined notification information relating to a power difference between a reception power value relating to a radio signal transmitted from a mobile radio communication terminal and a predetermined setting reception power value. And wherein the mobile radio communication terminal changes a transmission power value within a range not exceeding a predetermined maximum transmittable power value according to the power difference determined based on the notification information. In the wireless communication terminal, a communication that determines a reception power value at the wireless base station based on the notification information, and calculates a communication quality value based on the reception power value, the maximum transmittable power value, and the transmission power value. A mobile radio communication terminal comprising quality value calculation means. 3. The mobile radio communication terminal on the transmitting side, wherein the radio base station transmits predetermined notification information regarding a power difference between a reception power value regarding a radio signal transmitted from the mobile radio communication terminal and a predetermined set reception power value. And the mobile radio communication terminal sets the reception power value within a range that does not exceed a predetermined maximum transmittable power value, according to the power difference determined based on the notification information. A mobile radio communication terminal used in a mobile communication system that changes the received power value so as to have a received power value, comprising: a communication quality value calculating unit that calculates a communication quality value by a ratio between the maximum transmittable power value and the transmission power value. A mobile wireless communication terminal characterized by the above-mentioned. 4. A mobile base station and a mobile radio communication terminal which transmit and receive a spread-spectrum modulated radio signal to enable mobile communication by the mobile radio communication terminal. Notifies the mobile radio communication terminal of predetermined notification information regarding a signal-to-interference-wave power ratio of a radio signal transmitted from the mobile radio communication terminal,
The mobile radio communication terminal is used in a mobile communication system that changes a transmission power value within a range that does not exceed a predetermined maximum transmittable power value according to the signal-to-interference-wave power ratio determined based on the notification information. In the mobile radio communication terminal to be determined, the signal-to-interference wave power ratio is determined based on the notification information, a communication quality value based on the signal-to-interference wave power ratio, the maximum transmittable power value, and the transmission power value A mobile radio communication terminal, comprising: a communication quality value calculating means for calculating a value. 5. A mobile radio communication terminal that changes transmission power within a range not exceeding a predetermined maximum transmittable power value according to a reception power value of a radio signal transmitted from a radio base station, Control channel power value measuring means for measuring a received power value of a control channel transmitted from the radio base station, based on the received power value measured by the control channel power value measuring means and the maximum transmittable power value A mobile radio communication terminal comprising: a communication quality value calculating unit that calculates a communication quality value. 6. A mobile communication system which enables mobile communication by a mobile radio communication terminal by transmitting and receiving a spread spectrum modulated radio signal between a radio base station and a mobile radio communication terminal. The base station has a total received power value measuring means for measuring a total received power value for all radio bands allocated to the base station, and transmits the total received power value measured by the total received power value measuring means on a control channel. A control channel power value measuring means for measuring a received power value related to the control channel, comprising: a total received power value notifying means for notifying the mobile radio communication terminal; Before the reception power value measured by the channel power value measurement means, the maximum transmittable power value of the mobile radio communication terminal and the notification on the control channel. A mobile communication system comprising: a communication quality value calculating unit that calculates a communication quality value based on the total received power value. 7. A mobile communication system which enables mobile communication by a mobile radio communication terminal by transmitting and receiving a spread spectrum modulated radio signal between a radio base station and a mobile radio communication terminal, The mobile radio communication terminal includes: a control channel power value measurement unit that measures a reception power value related to a control channel; and the reception power value measured by the control channel power value measurement unit and a maximum transmittable power of the mobile radio communication terminal. In a radio base station used in a mobile communication system, one having communication quality value calculating means for calculating a communication quality value based on the value and the total received power value broadcast on the control channel, Total received power value measuring means for measuring all received power values for all radio bands allocated to the mobile terminal; and Radio base station, characterized by comprising a total received power value informing means for informing the total received power value toward the mobile wireless communication terminal over the control channel. 8. A mobile communication system that enables mobile communication by the mobile radio communication terminal by transmitting and receiving a spread spectrum modulated radio signal between a radio base station and the mobile radio communication terminal, The radio base station includes: a total reception power value measuring unit that measures a total reception power value for all radio bands assigned to the radio base station; anda control unit that transmits the total reception power value measured by the total reception power value measurement unit on a control channel. In a mobile radio communication terminal used in a mobile communication system in which the mobile radio communication terminal is provided with a total reception power value notifying means for notifying the mobile radio communication terminal, a reception power value for the control channel is measured. Control channel power value measurement means; and the reception power value measured by the control channel power value measurement means and the maximum transmittable power of the mobile radio communication terminal. Mobile radio communication terminal, characterized by comprising a communication quality value calculating means for calculating a communication quality value based on the notification has been the total reception power value value and on said control channel.