JPS60178732A - Busy channel switching system - Google Patents

Abstract

PURPOSE:To enable a base station to measure the reception field intensity or S/N in a fixed cycle by providing a means to a mobile station to give a periodical rise to a transmitter for a fixed period of time in case the mobile station has discontinuous transmissions. CONSTITUTION:A mobile station gives a rise to a transmitter at least for a period T2 and every cycle T1 regardless of the presence or absence of a sound signal. In other words, the mobile station gives immediately the first rise to the transmitter with a talking channel and thereafter performs the rise of transmitter every cycle T1. Therefore it is always possible for a base station to measure the reception field intensity with the same cycle and period as the rise of the transmitter at the mobile station. In other words, the base station designates a talking channel to the mobile station and then waits for and detects the first rise of the transmitter while measuring said reception field intensity. Hereafter the base station performs measurement for a period T2 every cycle T1. Then the base station monitors the reception field intensity through each measurement and switches the talking channel in case said field intensity is less than the threshold value.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a mobile telephone system that performs tracking exchange, and in particular, to channel switching during a call to smoothly continue a call when a mobile station performs discontinuous transmission. Regarding the method.

[Prior art]

Mobile telephone systems are used not only for specialized applications such as taxi radios, but also for communications aimed at the general public, such as ship telephones and train telephones.

Since mobile equipment does not have a fixed accommodation location with respect to the exchange, it is necessary to handle mobile equipment in a fixed manner for each service area for switching control, but since calls cannot be interrupted, the tracking exchange function I try to keep the call going continuously. Now, in order to effectively use radio frequencies and effectively increase the number of call lines, there is a method to make the wireless zones that make up the service area smaller and to repeatedly use the same wireless channels/channels regionally. However, as a result of this, there is a tendency to move across the boundaries of the wireless zone during a call, and the electric field strength changes rapidly near the boundaries of the wireless zone. Switching will be necessary. Conventionally, channel switching during a call for a mobile station that does not perform discontinuous transmission is activated by detecting deterioration in the received field strength or signal-to-noise ratio at the base station of radio waves transmitted from the mobile station, and after this activation, the base station The received field strength or signal-to-noise ratio is measured at base stations in multiple wireless zones adjacent to the wireless zone in which the station is communicating, and the best received field strength or signal-to-noise ratio is obtained. When it is determined that the mobile station has moved to the wireless zone, a busy channel switching signal is sent to the mobile station to switch to the conversation channel of the wireless zone to which the mobile station has moved, thereby executing the busy channel switching. Furthermore, since the base station must measure the received field strength or signal-to-noise ratio for a mobile station that performs discontinuous transmission, it transmits a control signal that causes the mobile station to start up its transmitter. Then, the mobile station is configured to receive this control signal and transmit a response control signal in response to this signal, so the base station measures the electric field strength or signal-to-noise ratio of the response control signal and performs the above-mentioned method. During a call, channel switching is performed in the same way as for mobile stations that do not perform discontinuous transmission.

Therefore, in this conventional busy channel reassignment method for mobile stations that perform discontinuous transmission, the received field strength or signal-to-noise ratio is measured by the base station when the mobile station's transmitter is not turned on. Since a control signal is sent and received every time a call is made, the mobile station has the disadvantage that the control signal reaches the caller's ears as noise from the beginning of the control signal until the control signal is detected and the communication path is disconnected. There was a thunderstorm.

[Summary of the invention]

The present invention is applicable to a mobile telephone system that performs tracking exchange, in which a mobile station continuously transmits cine depending on the presence or absence of voice, etc.
Regardless of the presence or absence of this audio, the transmitter is configured to turn on for a certain period of time at a predetermined period during a call.
The base station measures the received field strength or signal-to-noise ratio at this period.

〔Example〕

Now, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a transmitting section of a mobile station that performs discontinuous transmission in response to the presence or absence of voice, and shows one embodiment of the present invention.

1 is a large terminal for audio signals, 2 is an input terminal for control signals, 3
is an output terminal for the amplified signal. Reference numeral 10 denotes an audio detection section that detects an audio signal, 11 an audio signal modulation section, 12 a power amplification section for the modulated audio signal, and 13 an OR section that receives the detection signal 101 and the control signal 102 as inputs. That is, the audio signal supplied to the input terminal 1 is transmitted to the audio detection section 10.
and is inputted to the modulation section 11. The detection signal 101 detected by the voice detection section 10 is passed through the logical sum section 13 as a signal 103 to operate the power amplification section 12, so that the modulated voice signal is amplified and sent out from the output terminal 3. On the other hand, a control signal 103 supplied to the input terminal 2 from a control section of a mobile device (not shown) passes through an OR section 13 and operates the power amplification section 12 as a signal 103. Therefore, the operation of the power amplifying section 12 is largely controlled by the logical sum of the audio signal and the control signal. FIG. 2 is a time chart illustrating the operation of one embodiment configured as described above. (5) indicates a signal 101.03 outputted from the voice detection section 10, a signal 102 supplied from a control section of a mobile device (not shown), and a signal 103 outputted from the disjunction section 13 (C). The power amplifying section 12 operates when the signal 103 is at the "1" level, and stops operating when the signal 103 is at the "0" level. (6
), @ indicate the control of adjacent base stations, the horizontal axis indicates the time corresponding to the above, ω), (Q, and the vertical axis indicates the received electric field strength measured at each base station. The dotted line in the figure indicates the fluctuation in received field strength that would be obtained at each base station when the mobile station transmits continuously1, and the dashed line indicates whether to activate channel switching during a call. It is activated when the received field strength becomes lower than this threshold.

Here, the operation of this embodiment will be explained with reference to FIG. The mobile station starts up its transmitter for at least 12 hours every period T1, regardless of the presence or absence of a voice signal. That is, when the mobile station moves to a communication channel, it immediately starts up its transmitter for the first time, and thereafter starts up its transmitter every cycle T1. (Period T of the signal shown in (4)
I, time T2).

Therefore, the base station can always measure the received electric field strength in the same period of one hour.

That is, after specifying a telephone channel to a mobile station, the base station detects the first start-up of the transmitter by waiting while measuring the received field strength.

(Time to of the signal shown in (6)). After that, measurements are performed for 12 hours every cycle T1.

The base station monitors the received field strength through each measurement, and when it is determined that it is below the threshold value, activates channel switching during a call. (Time h of the signal shown in (2)). In other words, a base station that connects a mobile station to a communication channel and detects a deterioration in received field strength notifies the control station, which is a higher-level station, to that effect. issues a command to measure the received electric field strength. The base station that receives this command starts measurement after receiving this command, but if it detects a received field strength that is higher than a predetermined value, it will calculate the average value of the received field strength over the next 12 hours. Report to control station. (Time T2 of the signal shown in (6)). Therefore, the control station compares the measured values reported from the plurality of base stations, determines the wireless zone to which the mobile station will migrate, and at the same time sends a busy channel switching signal to the mobile station through the base station before migration. The destination base station also starts measuring the received field strength on the new communication channel.

When the mobile station receives this busy channel switching signal and moves to a new call channel, it immediately starts up its transmitter at cycle T1, and the base station to which the transfer is made starts the first mobile station transmitter on the new call channel. It is detected by waiting while measuring the received electric field strength. (Time ts of the signal shown in (6)).

Thereafter, measurements are performed for 12 hours every period Tl to obtain the received electric field strength.

〔Effect of the invention〕

In a mobile telephone system that performs tracking exchange, the present invention enables the transmitter of a mobile station that performs discontinuous communication to start up at a predetermined period, and does not use a control signal. Furthermore, it is now possible to know the measurement timing of the received field strength or signal-to-noise ratio at the base station without using a control signal.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a transmitter showing an embodiment of the present invention, and FIG. 2 is a time chart showing the operation of this embodiment. 1.2...-input terminal, 3... bone/output terminal, 10...
...Audio detection section, 11...Modulation section, 12...
Power amplification section, 13 φ... logical sum section. Patent Applicant NEC Corporation Agent Masaki Yamakawa (and 2 others) Figures 1 and 2

Claims (1)

[Claims] When a mobile station moves during a call between multiple radio zones that make up a service area, the tracking exchange function allows the mobile station to continue talking continuously. A channel switching system during a call is characterized in that, when transmitting, a means is provided to periodically turn on a transmitter for a certain period of time during a call to a mobile station.