WO1999034627A1

WO1999034627A1 - Radio communication device

Info

Publication number: WO1999034627A1
Application number: PCT/JP1997/004792
Authority: WO
Inventors: Atsuya Kume
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 1997-12-24
Filing date: 1997-12-24
Publication date: 1999-07-08
Also published as: GB9919781D0; GB2337184B; GB2337184A

Abstract

The speech quality of radio communication device for communication with a base station in a communication area through a portable radio terminal is improved by reducing the frequency of hand-over by changing the starting condition under which hand-over is started in accordance with the history of hand-over.

Description

Description Wireless communication device Technical field

The present invention relates to a wireless communication device that performs wireless communication with a base station in a communication area using a portable wireless terminal. Background art

FIG. 1 is a configuration diagram showing a wireless communication device using a portable wireless terminal. In the figure, a central base station 3 between a base station 1 in a communication area E 1 and a base station 2 in a communication area E 2 is illustrated. Connected via. The mobile wireless terminal 4 in the communication area E1 communicates with the base station 1 by, for example, frequency multiple access (FDMA) or time division multiple access (TDMA). FIG. 2 is a block diagram showing the configuration of the portable wireless terminal. In the figure, 10 is a transmitting / receiving antenna, 11 is a radio section, 12 and 13 are an audio processing section and a central control section (hereinafter, CPU). ), 14 and 15 are a microphone and a speaker connected to the audio processing unit 12, 16 is a ROM that stores a control program, and 17 is a memory that temporarily stores the program processing data. RAM, 18 stores the local telephone number and the telephone number of the other party. RAM, 19 is a display unit, 20 is an operation unit. These are ROM 16, RAM I 7, 18 The display unit 19 and the operation unit 20 are connected to the CPU 13.

Next, the operation will be described.

Now, in the communication area Ε1 of the base station 1, when the ten keys or the shortening buttons of the operation unit 20 of the portable wireless terminal 4 are operated, the CPU 13 which has inputted the operation signal receives R ΟΜ16, RAM I 7, Between 1 8 and de overnight The communication is performed, and the destination telephone number is transmitted via the radio section 11 and the transmitting / receiving antenna 10.

The base station 1 receiving this transmission signal sends a transmission signal to the other party's base station 2 through the central base station 3 and sends the transmission signal from the base station 2 to the other's portable wireless terminal 5, and the two portable wireless terminals 4, 5 Connect to a call-enabled state. After connection, the audio is converted to an electric signal by the microphone 14, processed by the audio processing unit 12, and transmitted via the radio unit 11 and the transmitting / receiving antenna 10. The transmission signal from the other party is input to the audio processing unit 12 via the transmission / reception antenna 10 and the radio unit 11, processed by the audio processing unit 12, and then output as sound from the speaker 15. Make a call.

At the time of the above call, the radio wave from the base station 1 received by the transmitting / receiving antenna 10 is input to the radio unit 11 to measure the electric field level and the line quality. CP 13 compares the electric field level and line quality measured by radio section 11 with a certain threshold. According to the Second Generation Cordless Telephone System Standards, First Edition (RCRSTD-28) issued by Radio System Development Center Yuichi and January 1993, the threshold value was determined by the base station Is notified in advance.

If the CPU 13 determines that the electric field level or the line quality is below the threshold value as a result of the comparison, it issues a handover instruction, and the radio unit 11 starts handover according to the instruction.

Since the conventional wireless communication device is configured as described above, even if there is no base station that should be handed over, if the received radio wave deteriorates and falls below the threshold, for example, Since the handover operation is performed at intervals of 5 seconds, the handover causes a two-second break in the voice, resulting in a problem that the call quality is significantly deteriorated.

The present invention has been made to solve the above-described problems, and a When there are no base stations to be overhung, the purpose is to improve the communication quality by reducing the frequency of handover operations. Disclosure of the invention

The invention relates to a radio unit connected to a transmitting / receiving antenna, and comparing one or both of the electric field level and the line quality measured by the radio unit with a threshold value. By providing a handover instruction to the radio unit and a control unit for lowering the threshold when handover by the handover instruction fails, unnecessary handover is reduced and communication quality is reduced. improves.

Further, the present invention includes a selection device for selecting whether to change the handover condition according to the handover failure or to keep the handover condition fixed irrespective of the handover failure. In addition, it is possible to prevent unnecessary change of the handover condition in the area where the communication condition is good.

Further, according to the present invention, by changing the time during which the next handover can be started according to the handover failure, unnecessary handover is reduced and communication quality is improved.

In addition, the present invention sets the time at which the next handover can be started in response to the handover failure, and / or the threshold for comparing the electric field level and the line quality measured by the radio unit. By changing, unnecessary handover is reduced and communication quality is improved.

In addition, the present invention sets the time when the next handover can be started in response to the success of the handover, and / or the threshold for comparing the electric field level and the line quality measured by the radio unit. By changing, it is possible to prevent unnecessary change of the handover condition in the area where the communication condition is good.

Also, the present invention provides a radio unit connected to a transmitting / receiving antenna, If one or both of the electric field level and the line quality measured by the radio communication unit are equal to or less than the threshold value, a handover instruction is output to the radio unit, and a handover by the handover instruction is performed. A control unit for lowering the threshold value when a failure has occurred, and a handover execution unit capable of forcibly executing a handover regardless of the electric field level and / or the line quality. Thus, handover can be forcibly executed according to the user's will.

Further, the present invention provides a radio unit connected to a transmitting / receiving antenna, and comparing one or both of the electric field level and the line quality measured by the radio unit with a threshold value, A handover instruction is output to the radio unit, and when the handover by the handover instruction fails, the control unit lowers the threshold value, and the control unit reduces the threshold value, regardless of the electric field level and / or the line quality. And handover prohibition means to prevent handover from being performed, the handover can be prohibited by the user's will, reducing unnecessary handover and improving communication quality. Can be improved. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram showing a wireless communication system using a mobile wireless terminal, FIG. 2 is a block diagram showing a configuration of a mobile wireless terminal, and FIG. 3 is a diagram of a wireless communication device according to a first embodiment of the present invention. FIG. 4 is a flowchart showing the operation, FIG. 4 is a flowchart showing the operation of the wireless communication apparatus according to the second embodiment of the present invention, and FIG. 5 is an operation of the wireless communication apparatus according to the third embodiment of the present invention. FIG. 6 is a flowchart showing the operation of the wireless communication apparatus according to Embodiment 4 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiment 1

The configurations of the wireless communication device and the portable wireless terminal according to the present invention are the same as those shown in FIGS. 1 and 2, and the wireless section 11, the CPU 13, and the operating section 2 which are the constituent elements of the portable wireless terminal. 0 is a new function.

FIG. 3 is a flowchart showing the operation of the wireless communication apparatus according to Embodiment 1 of the present invention. When the operation is started, a threshold value is set to a default value (TH.) In step ST1.

Next, as shown in FIG. 2, the radio unit 11 measures one or both of the received electric field level and the line quality, and inputs the measured value to the CPU 13. The CPU 13 compares one or both of the electric field level and the line quality with the threshold value (step ST 2) to determine whether the threshold value has been exceeded (step ST 3). Are repeated, and if YES, a handover instruction is output to the radio section 11 (step ST4).

Thereafter, the radio section 11 executes the handover based on the handover instruction and determines whether the handover is successful (step ST5). If the handover fails, the threshold value is set to the default value TH. Set it to a smaller value (step ST 6). Therefore, the next handover starts handover when the value falls below the newly set threshold. Therefore, when the electric field level and the line quality are the same, the repetition of handover is reduced.

On the other hand, as a result of the determination in step ST5 above, it is determined that handover was successful. The default value based on the threshold value. It is to return to.

Embodiment 2

FIG. 4 is a flowchart showing the operation of the wireless communication apparatus according to Embodiment 2 of the present invention, in which the threshold value is changed stepwise according to the number of handover failures.

Hereinafter, a specific description will be given. When the operation starts, the default value (Τ Η) is set to the threshold value in step SΤ11, and the number of handover failures η = 0 is set in step SΤ12.

Next, one or both of the electric field level and the line quality received by the radio unit 11 are measured and input to the CPU 13. The CPU 13 compares one or both of the electric field level and the line quality with the threshold value (step ST 13), determines whether the value has fallen below the threshold value (step ST 14), and sets N 0. If so, the above determination is repeated, and if YES, a handover instruction is output to radio section 11 (step ST15).

Thereafter, the radio section 11 performs the handover based on the handover instruction and determines whether the handover is successful (step ST16), and if the handover fails, increases the number n of handover failures by one (step ST16). ST 17), the threshold is lowered and set to the default value (TH «) (step ST 18). For example, if handover fails two consecutive times, the threshold is further reduced by setting n = 2.

On the other hand, if the handover is successful, the number n of handover failures is returned to 0 (step ST19), and the threshold value is set to the default value TH. (Step ST 20). That is, it returns to the initial setting state all at once.

Embodiment 3. In Embodiment 2 described above, once the handover fails, the threshold is lowered, and when the handover succeeds, the threshold is returned to the original state. However, the operation unit determines whether or not to perform this operation. FIG. 5 is a flowchart showing the operation of the wireless communication apparatus according to the third embodiment of the present invention.

Hereinafter, a specific description will be given. When the operation starts, the threshold value is set as a default value (TH) in step ST21.

Next, one or both of the electric field level and the line quality received by radio section 11 are measured and input to CPU 13. The CPU 13 compares one or both of the electric field level and the line quality with a threshold value (step ST22), determines whether the threshold value has been exceeded (step ST23), and sets N0. If so, repeat the above determination. If YES, wireless section 11 outputs a handover instruction and executes handover (step ST 24

) o

Thereafter, it is determined whether the handover is successful (step ST25), and if the handover fails, it is determined whether the input is fixed (step ST26). If so, the threshold is changed (step ST27). If it is determined in step ST25 that the handover is successful, it is determined whether the input is fixed (step ST28). Return the threshold to the default value (step ST29) o Embodiment 4.

In the first embodiment, when the handover fails, the threshold value is lowered, and when the handover succeeds, the threshold is restored.However, when the handover fails, the next handover may not be performed for a certain period of time. Fig. 6 shows the invention When the operation, which is a flowchart showing the operation of the wireless communication apparatus according to the fourth embodiment, is started, the handover inhibition time is set to a default value (step ST31). Next, one or both of the electric field level and the line quality received by the radio unit 11 are measured and input to the CPU 13. The CPU 13 compares one or both of the electric field level and the line quality with the threshold value (step ST32), determines whether or not the threshold value has been exceeded (step ST33), and determines whether the answer is NO. If so, repeat the above determination. If YES, determine whether handover is prohibited (step ST34). If YES, return to step ST32. If NO, perform handover. Step ST 35 5).

Thereafter, it is determined whether the handover is successful (step ST36). If the handover is successful, the prohibition time is restored (step ST37), and if the handover fails, the prohibition time is changed (step ST37). Step ST38) returns to step ST32, and repeats the above operation.

Therefore, the next handover starts a handover after the newly set prohibition time. For this reason, repetition of handover is reduced. Embodiment 5

In the fourth embodiment, when the handover fails, the next handover is not performed for a certain period of time.However, the time until the next handover can be started is changed stepwise according to the number of failures. Is also good. For example, in the case of two consecutive failures, the time for starting the next handover may be further extended. Also, the prohibition time when handover fails may be changed according to how many times handover has failed. Embodiment 6

In the fourth embodiment, when the handover fails, the next handover is not performed for a certain period of time.However, the operation unit 20 may be provided with a selection unit for selecting whether to perform the operation or not. Good. Embodiment 7

In Embodiments 1 to 3, the threshold is changed when handover fails, and in Embodiments 4 to 6, the time at which the next handover can be started when handover fails is changed. Although shown, both may be changed simultaneously. Embodiment 8

Embodiments 1 to 7 show that the condition of the handover is changed when the handover fails, but the condition of the handover may be changed by the success of the handover. For example, if the handover frequency is constantly monitored and the handover frequency becomes higher than a certain value, the threshold value may be changed or the handover start time may be changed. Good. Embodiment 9

Embodiments 1 to 8 show that handover is started based on the electric field level and line quality output from radio section 11, but regardless of output from radio section 11, The handover may be started or not performed by a request, that is, by a request signal input from the operation unit 3. Industrial applicability

As described above, the wireless communication apparatus according to the present invention is configured to lower the handover threshold value when handover fails, so that unnecessary handover without a handover destination is prevented. Prevent and improve communication quality.

Claims

The scope of the claims

1. If the radio unit connected to the transmitting / receiving antenna and one or both of the electric field level and the line quality measured by this radio unit are compared with a threshold value and are lower than the threshold value, the radio unit is connected to the radio unit. A wireless communication device comprising: a control unit that outputs a handover instruction and, when the handover by the handover instruction fails, decreases the threshold.

2. The claim 1 further comprising a selection device for selecting whether to change the handover condition according to the handover failure or to keep the handover condition fixed regardless of the handover failure. Wireless communication device.

3. The wireless communication according to claim 1, wherein the time at which the next handover can be started is changed according to the failure of the handover.

4. In response to the handover failure, the time at which the next handover can be started and / or the threshold for comparing the electric field level measured by the radio unit and the line quality are changed. The wireless communication device according to claim 1, wherein

5. According to the success of the handover, the time to start the next handover and / or the threshold for comparing the electric field level and the line quality measured by the radio unit are changed. 2. The wireless communication device according to claim 1, wherein

6. If the radio unit connected to the transmitting / receiving antenna and one or both of the electric field level and the line quality measured by this radio unit are less than the threshold value, and are below the threshold value, the radio unit will hang. A handover instruction is output, and when the handover by the handover instruction fails, the control unit for lowering the threshold value and the handover regardless of either or both of the electric field level and the line quality. A wireless communication device comprising: a handover executing means for forcibly executing a handover.

7. If the radio unit connected to the transmitting / receiving antenna and one or both of the electric field level and the line quality measured by the radio unit are compared with the threshold value and are lower than the threshold value, the radio unit is connected to the radio unit. A handover instruction is output, and when the handover by the handover instruction fails, the control unit for lowering the threshold value and the handover regardless of either or both of the electric field level and the line quality. A wireless communication device having a handover prohibiting means for preventing handover.