JP2000156661A - Mobile radio station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption without deteriorating cell re-selection performance. SOLUTION: A mobile radio station is provided with a received electric field strength comparison section 51 that compares the reception electric field strength of its own cell measured by a reception electric field strength measurement section 41 with a predetermined threshold value, a reception electric field strength deterioration rate calculation section 52 that calculates the reduction rate of the reception electric field strength of its own cell on the basis of the measurement result in the reception electric field strength measurement section 41, a reception electric field strength reduction rate comparator section 53 that compares the reduction rate of the reception electric field strength of its own cell calculated by the reception electric field strength deterioration rate calculation section 52 with a predetermined threshold value, and a mode changeover section 54 that selects a mode of the reception electric field strength measurement section 41 on the basis of the comparison result by the reception electric field strength reduction rate comparator section 53. The number of radio base stations whose reception electric field strength is to be measured is controlled according to the reception electric field strength of its own cell and the reduction rate of the reception electric field strength of its own cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a GSM (Global S
The present invention relates to a mobile radio station such as a mobile phone, and more particularly to monitoring control of a radio base station in a mobile radio station.

[0002]

2. Description of the Related Art Conventionally, in a GSM system, four TDMA frames are reserved for every n multiplex frames as a paging channel in each radio base station. The value of n can be set to any one of 2 to 9 for a specific wireless base station. Also,
A single block paging channel frame is used by a mobile radio station to confirm an incoming call from the radio base station with which it is currently communicating or to receive signals transmitted from two adjacent radio base stations within each frame. It is long enough to measure the electric field strength.

[0003] Thereby, the mobile radio station can measure the received electric field strength of the signal transmitted from eight adjacent radio base stations for every n multiplex frames.

[0004]

However, in the conventional mobile radio station as described above, when two monitoring operations are performed for each paging channel TDMA frame, for example, handoff to an adjacent radio base station is urgently performed. However, when a mobile radio station exists at a position that does not need to be performed at the center of the cell, a considerable amount of power is wasted.

[0005] Further, when a relatively small number of monitor operations are set to reduce power consumption, there is a problem that the cell reselection performance is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been developed in order to reduce power consumption without deteriorating cell reselection performance. It is an object of the present invention to provide a mobile radio station capable of reducing the frequency of monitoring the station.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention measures a received electric field strength of a signal transmitted from a predetermined maximum number of adjacent radio base stations. It comprises two modes: a full monitoring mode, and a simplified monitoring mode for measuring the reception electric field strength of signals transmitted from a smaller number of radio base stations than the number in the full monitoring mode among the adjacent radio base stations. Measuring means for periodically measuring the reception electric field strength of signals transmitted from a plurality of adjacent radio base stations and the reception electric field strength of the own cell in one of the two modes; Calculating means for calculating the rate of decrease of the received electric field strength of the own cell measured by the means, and the rate of decrease of the received electric field strength of the own cell calculated by the calculating means is predetermined. A first comparison means for comparing have value,
If the result of the comparison by the first comparing means is that the rate of decrease of the received electric field strength of the own cell calculated by the calculating means exceeds the threshold value, the mode of the measuring means is changed to the full monitoring mode. And setting the mode of the measuring means to the simplified monitoring mode when the rate of decrease of the received electric field strength of the own cell calculated by the calculating means is equal to or less than the threshold value. Means.

[0008] Further, there is provided second comparing means for comparing the received electric field strength of the own cell measured by the measuring means with a predetermined threshold value, wherein the calculating means comprises the second comparing means. The result of the comparison is that only when the received electric field strength of the own cell measured by the measuring means is less than the threshold value, the decrease rate of the received electric field strength of the own cell is calculated. And

[0009] The measuring means may receive an instruction about the frequency of a time slot available for measuring the received electric field strength from the radio base station.

[0010] The measuring means can measure the received electric field strength of signals transmitted from a plurality of adjacent radio base stations in one time slot.

Further, the measurement means performs an operation of measuring a maximum number of received electric field strengths in an available TDMA frame in the full monitoring mode.

Further, the measuring means performs one measurement operation of the received electric field strength in one TDMA frame from available TDMA frames in the simplified monitoring mode.

[0013] Further, the measuring means performs the measurement operation of the received electric field strength in a specific slot among available time slots in the simplified monitoring mode.

[0014] Further, the selection of the number of time slots for measuring the received electric field strength is determined by an instruction of the frequency of available time slots.

(Operation) In the present invention configured as described above, the received electric field strength of signals transmitted from the own cell and a plurality of adjacent radio base stations is measured, and the received electric field strength of the own cell is measured. When the value is less than the predetermined threshold, the decrease rate of the reception electric field strength of the own cell is calculated, and the decrease rate of the reception electric field strength of the own cell exceeds the predetermined threshold value. In the case, among the adjacent radio base stations, the reception electric field strength of a signal transmitted from a predetermined maximum number of radio base stations is measured, and the reception electric field strength of the own cell is equal to or more than a predetermined threshold value. Or, if the decrease rate of the received electric field strength of the own cell is equal to or less than a predetermined threshold, among the adjacent radio base stations, transmission is performed from a smaller number of radio base stations than the maximum number. The received field strength of the signal It is constant.

As described above, the number of radio base stations for measuring the received electric field strength is controlled based on the received electric field strength of the own cell and the reduction rate of the received electric field strength of the own cell. Without reducing the power consumption, the power consumption can be reduced.

[0017]

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

FIG. 1 is a diagram showing a configuration example of a cellular radio communication network in which a mobile radio station according to the present invention is used.

As shown in FIG. 1, in the present configuration example, radio base stations 20-1 to 20-n are provided in the service area with cells 10-1 to 10-n as service areas, respectively. Cell 10 with multiple service areas
-1 to 10-n. Also, cell 10-6
The mobile radio station 30 is located within.

Although only one mobile radio station 30 is shown in FIG. 1, there are a plurality of mobile radio stations in the service area.

FIG. 2 is a block diagram showing an embodiment of the mobile radio station 30 shown in FIG.

In this embodiment, as shown in FIG.
An antenna 31 and an RF stage 32 for transmitting and receiving data and control signals to and from 0-1 to 20-n;
1 and means for temporarily converting the signal received via the RF stage 32 to a digital signal and means for temporarily storing the signal converted to a digital signal, and are in charge of many of the basic logical operations in the mobile radio station 30. A digital signal processing unit 33, a RAM 35, and a ROM 36. The digital signal processing unit 33 processes a signal converted into a digital signal, and receives a user's input from a keypad (not shown) of the mobile radio station 30. CPU3 that receives instructions
4 and a SIM module 37 connected to the CPU 34 and communicating with the CPU 34 in a known manner.

Here, the digital signal processing unit 33 measures the received electric field strength of the signal transmitted from the radio base station currently communicating and the received electric field strength of the signal transmitted from the adjacent radio base station. Receiving electric field strength measuring section 4
1, a full monitoring mode for measuring the reception electric field strength of a signal transmitted from a predetermined maximum number of radio base stations among the adjacent radio base stations, and a measurement mode for the adjacent radio base stations. One of the simple monitoring modes in which the reception electric field strengths of the signals transmitted from the wireless base stations smaller than the maximum number in the full monitoring mode among the base stations are set.

The CPU 34 also includes a reception electric field strength comparison section 51 as a second comparison means for comparing the reception electric field strength of the own cell measured by the reception electric field strength measurement section 41 with a predetermined threshold value. A reception field strength reduction rate calculation section 52 for calculating a reduction rate of the reception field strength of the own cell based on the measurement result in the reception field strength measurement section 41; Based on a comparison result of the reception electric field strength reduction rate comparing section 53 as the first comparing means for comparing the reduction rate of the reception electric field strength of the cell with a predetermined threshold value, and the reception electric field strength reduction rate comparing section 53 A mode switching unit 54 for switching the mode of the reception electric field strength measurement unit 41 is provided.
The CPU 34 holds a BA list including a list of adjacent wireless base station IDs and a frequency at which the control channel is operating, which is added to data transmitted from 1 to 20-n.

The latest received electric field intensity measured by the received electric field intensity measuring section 41 is held in the CPU 34.

From the radio base stations 20-1 to 20-n, a period for separating a paging channel (PCH) TDMA frame is specified as a numeral 2 to 9 representing a period relating to the number of GSM multiplex frames generated in the period. Data is provided. When the number (bs_pa_mfrms) is 2, there is one PCH frame for every other multiplex frame, and when the number is 9, eight multiplexes are performed between multiplex frames having one PCH frame. There is a frame.

FIG. 3 is a diagram showing the separation of PCH TDMA frames.

Further, data for specifying the position of the PCH frame in the multiplex frame is provided from the radio base stations 20-1 to 20-n, but is not described here because it is not related to the present invention.

Conventionally, when the mobile radio station 30 is in an idle mode in which a call is not performed, the digital signal processing unit 3
In 3, the received electric field strength of the signal transmitted from the adjacent radio base station is measured, and the measurement is performed twice for each PCH frame.

In this manner, the data on the received field strength of the signal transmitted from the adjacent radio base station is kept as up-to-date as possible, and when a handoff is requested, the mobile radio station 30 transmits the data to the BA list. , A new radio base station is selected, and all data necessary to start handoff are prepared.

In this embodiment, the frequency of measurement of the received electric field strength of a signal transmitted from an adjacent radio base station is reduced during normal operation, thereby excluding the case where handoff is determined to be urgently needed. The power used for measuring the received electric field strength is reduced.

The operation of measuring the received electric field intensity in the above-mentioned mobile radio station will be described below.

FIG. 4 is a flowchart for determining the measurement frequency of the received electric field strength in mobile radio station 30 shown in FIG.

First, the variable n_mons is set to 1 and the variable mon_n_in_5pch is set to the parameter bs_pa
The value is set to a value obtained according to the value of _mfrms (step S1).

As shown in FIG. 4, mon_n_in_
The value of 5pch is set to an integer part of 5/9 of bs_pa_mfrms plus 0.5. Thereby, mon_n_in_5pch becomes bs_pa_mf
If rms has the minimum value (2), it becomes 1 and bs
When _pa_mfrms has the maximum value (9), it becomes 5, which fluctuates within that range.

Next, in the received electric field strength comparing section 51,
Received electric field strength serv_l of the signal transmitted from the radio base station of the own cell, measured by received electric field strength measuring section 41
Evel is compared with a predetermined threshold thresh (for example, -90 dbm) (step S2).

If the result of the comparison in step S2 is that the reception electric field strength of the own cell measured by the reception electric field intensity measuring section 41 is smaller than the threshold value, Is calculated using the following equation (step S3).

Delta_eff = delta_ser
v × n_neigh / 4 × 5 / mon_n_in_5p
ch where delta_serv is the actual decrease in signal strength since the previous received field strength measurement, and n_
"neigh" is the number of wireless base stations listed in the BA list.

Next, the reception electric field intensity reduction rate comparing section 53 sets the maximum permissible signal intensity between monitors at which the reduction rate of the reception electric field intensity of the own cell calculated in step S3 becomes a predetermined threshold value. Value step indicating effective decrease
(For example, 12 dB) (step S4).

If the comparison result in step S4 indicates that the rate of decrease of the received electric field strength of the own cell calculated by the received electric field strength decrease rate calculating section 52 exceeds the threshold value,
The value of n_mons is set to 2 (maximum value)
The value of n_in_5pch is set to 5 (maximum value) (step S5).

The comparison result in step S2 is as follows:
When the received electric field intensity of the own cell measured by the received electric field intensity measuring unit 41 is equal to or more than the threshold value, or the comparison result in step S4 is calculated by the received electric field intensity decrease rate calculating unit 52. If the rate of decrease of the received electric field strength of the own cell is equal to or less than the threshold value, the process ends.

Thereafter, the values of the multiplex frame count and the pch frame count used by the DSP to determine whether or not to perform monitoring on a specific PCH frame are reset (step S6).

In the mode switching unit 54 in the CPU 34, the variables n_mons and mon_n_in_5pch
Is used to switch the mode of the reception electric field strength measurement unit 41.

FIG. 5 is a diagram showing the measurement timing of the reception electric field intensity in the reception electric field intensity measurement section 41 shown in FIG. 2. FIG. 5 (a) shows the timing when the measurement is performed twice in one PCH frame. FIG. 3B is a diagram illustrating timing when one measurement is performed in one PCH frame.

Under the control of the mode switching unit 54, n_m
When ons is set to 2, the mode of the reception electric field strength measurement unit 41 is set to one P as shown in FIG.
The mode is set to perform two measurements in the CH frame, and n
When _mons is set to 1, the mode of the received electric field strength measurement unit 41 is set to a mode in which one measurement is performed with one PCH frame as shown in FIG. 5B.

FIG. 6 is a timing chart showing a method of distributing the monitoring operation among the available PCH TDMA frames when the mode of the received electric field strength measuring section 41 shown in FIG. 2 is set to the simplified monitoring mode. FIG.

As shown in FIG. 6, mon_n_in_5
If the value of pch is set to 1, the received field strength measurement is performed using only the first possible PCH block of the five PCH blocks, and the received field strength is measured in the other four PCH blocks. No measurement is made.

When the value of mon_n_in_5pch is set to 2, the reception field strength is measured using the first two PCH blocks, and
That continues until the value of in_5pch is 5.

In the CPU 34, multiple frames and P
Separate counts are maintained for the CH frames and they are reset periodically, thereby controlling the received field strength measurements to be kept synchronized at all times.
These counts are reset by the CPU 34 when the full monitoring mode starts.

In the above embodiment, the variable mon_n_in_5pch is set to the parameter bs_pa
_Mfrms is determined according to the value of
The n_in_5pch value can also be obtained from the look-up table.

[0051]

As described above, in the present invention,
Since the number of radio base stations for measuring the received electric field strength is controlled based on the received electric field strength of the signal transmitted from the radio base station of the own cell and the reduction rate of the received electric field strength of the own cell, the cell reselection performance Power consumption can be reduced without reducing power consumption.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a cellular radio communication network in which a mobile radio station according to the present invention is used.

FIG. 2 is a block diagram showing an embodiment of the mobile radio station shown in FIG.

FIG. 3 is a diagram illustrating separation of a PCH TDMA frame.

FIG. 4 is a flowchart for determining a measurement frequency of a received electric field strength in the mobile radio station shown in FIG. 2;

5A and 5B are diagrams showing measurement timings of the reception electric field intensity in the reception electric field intensity measurement section shown in FIG.
FIG. 7B is a diagram illustrating timing when two measurements are performed in one PCH frame, and FIG. 7B is a diagram illustrating timing when performing one measurement in one PCH frame.

FIG. 6 shows the mode of the reception electric field strength measurement unit shown in FIG.
FIG. 7 is a timing diagram illustrating a method of distributing monitoring operations among available PCH TDMA frames when set to a simplified monitoring mode.

[Explanation of symbols]

 10-1 to 10-n cell 20-1 to 20-n radio base station 30 mobile radio station 31 antenna 32 RF stage 33 digital signal processing unit 34 CPU 35 RAM 36 ROM 37 SIM module 41 reception electric field strength measurement unit 51 reception electric field Intensity comparator 52 Received electric field strength reduction rate calculator 53 Received electric field strength decrease rate comparator 54 Mode switching part

Claims (8)

[Claims] 1. A full monitoring mode for measuring a received electric field strength of a signal transmitted from a predetermined maximum number of radio base stations among adjacent radio base stations, and a full monitoring mode among adjacent radio base stations. It comprises two modes: a simplified monitoring mode for measuring the received field strength of a signal transmitted from a smaller number of radio base stations than the number in the monitoring mode, and in one of the two modes, Measuring means for periodically measuring the received electric field strength of signals transmitted from a plurality of adjacent radio base stations and the received electric field strength of the own cell; and a decrease rate of the received electric field strength of the own cell measured by the measuring means. Calculation means for calculating the first comparison means, a first comparison means for comparing the rate of decrease of the received electric field strength of the own cell calculated by the calculation means with a predetermined threshold value, If the comparison result in the stage is such that the reduction rate of the reception electric field strength of the own cell calculated by the calculation means exceeds the threshold value, the mode of the measurement means is set to the full monitoring mode, When the rate of decrease of the reception electric field strength of the own cell calculated by the calculation means is equal to or less than the threshold value, switching means for setting the mode of the measurement means to the simplified monitoring mode. A mobile radio station characterized by the following. 2. The mobile radio station according to claim 1, further comprising: a second comparing unit that compares the reception electric field strength of the own cell measured by the measuring unit with a predetermined threshold value. The calculating means receives the own cell only when the comparison result of the second comparing means indicates that the received electric field strength of the own cell measured by the measuring means is less than the threshold value. A mobile radio station for calculating a reduction rate of an electric field strength. 3. The mobile radio station according to claim 1, wherein the measuring unit issues an instruction from the radio base station on a frequency of a time slot available for measuring the received electric field strength. A mobile radio station characterized by receiving. 4. The mobile radio station according to claim 3, wherein said measuring means can measure a received electric field strength of a signal transmitted from a plurality of adjacent radio base stations in one time slot. A mobile radio station, comprising: 5. The mobile radio station according to claim 4, wherein the measuring unit performs a measurement operation of a maximum number of received electric field strengths in an available TDMA frame in the full monitoring mode. Mobile radio station. 6. The mobile radio station according to claim 5, wherein the measuring unit measures the received field strength once in one TDMA frame from available TDMA frames in the simplified monitoring mode. A mobile radio station that performs an operation. 7. The mobile radio station according to claim 6, wherein the measuring unit performs the measurement operation of the received electric field strength in a specific slot among available time slots in the simplified monitoring mode. Mobile radio station. 8. The mobile radio station according to claim 7, wherein the selection of the number of time slots for measuring the received electric field strength is determined by an instruction of the frequency of available time slots. Radio station.