JP3014275B2 - Mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system in which a plurality of radio base stations form a radio zone, and a plurality of mobile stations move within and between radio zones to communicate with the base station. More specifically, the present invention relates to a mobile communication system in which a radio base station measures radio wave conditions of peripheral radio base stations and performs radio wave monitoring to determine which frequency is being used.

[0002]

2. Description of the Related Art In a mobile communication system in which a plurality of radio base stations form a radio zone and a plurality of mobile stations move within the radio zone and between radio zones to communicate with the base station, the radio base station is Radio waves including information for notifying the mobile station of the existence of the service area are constantly emitted during driving.

[0003] In mobile communication, when wireless areas are adjacent to each other, if the same frequency is used in that area, interference occurs and communication becomes impossible. Therefore, in order to avoid such a situation, conventionally, all humans manage the frequency of the radio wave emitted from the radio base station in relation to the location and the like of the radio base station, and the frequency of the radio wave emitted at each radio base station is controlled. Is set as a parameter.

Further, since the adjacency between the radio base stations changes daily depending on the surrounding environment and the new radio base station, radio waves emitted from the radio base stations are artificially managed as described above, and each radio base station is controlled. The station is changing settings as parameters.

[0005] There is also a method of receiving and monitoring a frequency used in a peripheral radio base station by a receiver. In this case, it is difficult to receive frequencies in the same band including the emission frequency during emission of radio waves. Conventionally, since it is impossible with a normal wireless receiver, it is conventionally performed using a dedicated receiver.

[0006]

As described above, conventionally, radio waves emitted from a radio base station are artificially managed, or a frequency used by a peripheral radio base station by using a dedicated receiver. The method of monitoring the reception is used, but the method of artificially managing the information is complicated, and in some cases, there is a problem that there is a mistake, and the method of using the dedicated receiver is expensive. However, there is a problem that an installation place is required.

[0007] The present invention has been made in view of the above,
It is an object of the present invention to provide a mobile communication system capable of economically and autonomously measuring the radio wave condition of peripheral wireless base stations without using a dedicated receiver.

[0008]

In order to achieve the above-mentioned object, according to the mobile communication system of the present invention, a plurality of radio base stations each constitute a radio zone, and a plurality of mobile stations communicate within a radio zone and between radio zones. A mobile communication system which moves and communicates with a base station, and wherein the radio base station constantly emits radio waves including information for notifying the mobile station of the existence of the service area during operation, the radio base station comprising: The station monitors traffic in the wireless area, detects traffic off-hours detecting means for detecting off-time of traffic, and the traffic off-time detecting means detects off-time of traffic. Means for stopping radio waves, a frequency information table in which frequencies that can be emitted from the radio base station are uniformly stored, and a reception table for receiving downlink radio waves from peripheral radio base stations. Means, when the emission of the radio wave is stopped for a predetermined time by the radio wave stopping means, during the predetermined radio wave stop time, the frequencies stored in the frequency information table are sequentially read, and the sequentially read frequencies are read out. Determining means for sequentially supplying to the receiving means and sequentially determining, for each frequency stored in the frequency information table, whether a radio wave of the same frequency as the frequency is used as a downlink radio wave from a peripheral radio base station; The gist is to have

Further, according to the mobile communication system of the present invention, the mobile station detects receiving means for receiving radio waves from the radio base station, and detects that the radio base station stops emitting the radio waves by the receiving means. Radio wave stop detecting means, a timer means for counting a time longer than the predetermined radio wave stop time when the radio wave stop detecting means detects that the emission of the radio wave is stopped, and the timer means continues the counting operation. While the operation is being performed, there is provided a stopover for in-service area transition that stops the in-service area transfer operation, and a release means for canceling the stop of the in-service area transfer operation by expiration of the timer means or re-reception of radio waves by the reception means. That is the gist.

[0010]

According to the mobile communication system of the present invention, when a traffic off time period is detected in the radio base station, the emission of radio waves is stopped for a predetermined time, and the radio wave is stored in the frequency information table during the predetermined radio stop time. Frequency is sequentially read out, and the sequentially read out frequency is sequentially supplied to the receiving means, and whether or not a radio wave having the same frequency as the frequency is used as a downlink radio wave from the peripheral radio base station is stored in the frequency information table. The determination is sequentially performed for each frequency set.

In the mobile communication system of the present invention, when the mobile station detects that the radio base station has stopped emitting radio waves by the receiving means, the timer means counts a time longer than the radio wave stop time, and While the timer means continues the counting operation, the in-service area transition operation is stopped, and the stop of the in-service area transfer operation is canceled by expiration of the timer means or re-reception of the radio wave by the receiving means.

[0012]

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

FIG. 1 is a block diagram showing a configuration of a radio base station 20 and a mobile station 21 which implement a mobile communication system according to one embodiment of the present invention. In FIG. 1, the radio base station 20 has a storage device 4, and the storage device 4 stores a peripheral search frequency information table 1 in which peripheral search frequencies are stored. Specifically, this peripheral search frequency information table 1 includes 1, 2,.
The radio frequency (channel code) is stored corresponding to an index number such as 0.

In the base station 20 shown in FIG.
The storage device 4 is connected to a data transmission bus line 7, to which a transceiver 2 having a frequency search reception function, a processing device 3, and a timer 5 are further connected.

The transceiver 2 has a reception function for frequency search, and is connected to the antenna 6 so that it can receive downlink radio waves from peripheral radio base stations. Is transmitted at all times during the operation, including radio wave information including information for notifying the mobile station 21 of the mobile station 21. This radio wave is transmitted as indicated by the arrow 13 in FIG. The information is transmitted from the base station 20 to the mobile station 21 as downlink notification information.

Further, the processing device 3 analyzes the traffic situation, and thereby determines the traffic off time zone. FIG. 4 shows an example of a traffic state in the wireless area measured by the processing device 3. In the case shown in FIG. 4, the traffic off time zone occurs around midnight between 12:00 and 12:00. Therefore, FIG.
In the example shown in FIG. 5, the traffic off time is shown as the implementation time zone, and as described later, the emission of the radio wave is stopped during the implementation time that is the traffic off time zone, and during this stop time, The radio wave condition of the peripheral wireless base station is measured.

The timer 5 is also used for analyzing the traffic situation in the processing unit 3 and also for detecting the above-mentioned traffic off-time period temporally, and for measuring the radio wave condition of the peripheral base station. Is temporarily stopped for a predetermined time, but also has a function for measuring the predetermined radio wave stop time.

On the other hand, the mobile station 21 has a receiving unit 8, a processing unit 9, and a timer 10 to which an antenna 11 is connected so as to receive radio waves from the base station 20, and these units are connected to a data transmission bus line 12. Connected to each other.

The processing section 9 monitors the downlink notification information radio wave from the base station 20 via the reception section 8 and detects the stop of the radio wave. When the radio wave stops, the mobile station 21 normally determines that the radio wave in its own area has dropped, and tries to start a relocation operation in which the mobile station 21 shifts to another area. When the stop of the radio wave is detected, the timer 10 is started. The timer 10 is set so as to perform a counting operation for a longer time than a predetermined radio suspension time for measuring the radio wave state of the peripheral base station in the base station 20. While the operation is continued, the mobile station 21 stops moving to the service area. Then, the mobile station 21 releases the suspension of the in-service area transition operation by expiration of the timer 10 or re-receiving the radio wave from the base station 20.

Next, the operation will be described with reference to the flowchart shown in FIG.

When the base station 20 starts operating, the base station 20 transmits a radio wave as shown in FIG. 3A including broadcast information for reporting the existence of the service area to the mobile station 21 via the antenna 6. From 2 as shown by the arrow 13 in FIG. 1, during operation, it is constantly fired, thereby notifying the mobile station 21 of the existence of the wireless area. The signal that sends this information includes
The mobile station also sends out necessary signals such as synchronization signals necessary for signal reception and battery saving.
The mobile station 21 receives the broadcast information in the receiving unit 8 via the antenna 11, waits in the area by the processing of the processing unit 9, waits for an incoming signal from the base station 20, and thereby, in the wireless area. Get outgoing and incoming services.

In such a state, the processing device 3 of the base station 20 observes the traffic situation in its own radio area after the start of operation, accumulates the observation results along the time axis using the timer 5, and A traffic off time zone is calculated in a typical manner, and the occurrence of a traffic off time zone is detected (steps 110 and 120 in FIG. 2).

When the base station 20 detects the occurrence of the traffic off time zone, it sequentially reads out the peripheral search frequencies from the peripheral search frequency information table 1 stored in the storage device 4 (step 130). At the same time, a predetermined radio stop time for stopping the emission of the radio wave, that is, a stop time is set in the timer 5 (step 140), and the stop of the radio wave is started. (Step 150). That is, the base station 20 stops the radio wave itself emitting the broadcast information.

Then, during this radio stop time, the transceiver 2 is switched to receive radio waves downstream from the base station, and the frequencies sequentially read out from the peripheral search frequency information table 1 are supplied to the transceiver 2, whereby the electric field corresponding to the frequency is changed. Instruct the transceiver 2 to measure the intensity (step 1
60). Then, the measured value from the transceiver 2 is received, and the value of the electric field management table for each frequency is updated based on the measured value, whereby it is determined whether or not the frequency is used in the peripheral base station (step). 17
0). When all the measurements for each frequency stored in the peripheral search frequency information table 1 have been completed and the timer 5 has expired, the base station 20 starts emitting radio waves again via the transceiver 2 and transmits the broadcast information. Start (step 180).

The period during which the emission of radio waves is stopped is defined as one unit of one cycle of the synchronization signal included with the broadcast information, and the unit of time required for radio wave measurement is stopped.

As described above, when the base station 20 stops emitting radio waves and the base station 20 monitors the radio waves during this suspension period, the radio waves from the base station 20 to the mobile station 21 are transmitted as shown in FIG. As shown in), the period is interrupted, the mobile station 21 enters the non-reception state, and attempts to perform the in-service switching operation. However, the timer 10 stops the in-service switching operation during the radio suspension period as described above. I have to.

That is, in the mobile station 21, when the base station 20 stops emitting radio waves, the processing unit 9 detects the stop of the broadcast information from the base station 20 based on the signal from the receiving unit 8, and the emission of the radio waves is stopped. Since the stop is identified, the processing unit 9 sets a waiting time for the re-receiving of the in-zone notification information in the timer 10 and starts the counting operation of the time. While the timer 10 continues the counting operation, the mobile station 21 stops the in-service switching operation, and the mobile station 21 monitors re-reception of the broadcast information. The mobile station 21 has a timer 1
When 0 expires or the radio wave stop operation in the base station 20 is canceled, the radio wave of the broadcast information is retransmitted from the base station 20. When the mobile station 21 receives the radio wave again, the mobile station 21 stops transmitting. The suspension of the zone transfer operation is released.

The period during which the mobile station 21 stops moving to the service area by the timer 10 may be longer than the time required for the base station 20 to perform the measurement.

Further, in the above embodiment, since the measurement of the radio wave condition of the peripheral base station is performed during the off-hours of traffic, the transmission from the mobile station 21 and the reception to the mobile station 21 hardly occur. Even if it occurs, it has a low impact on the service because it is low in probability.

[0030]

As described above, according to the present invention,
In the radio base station, the emission of radio waves is stopped for a predetermined time during the traffic off hours, the frequencies stored in the frequency information table are sequentially read during the predetermined radio stop time, and the sequentially read frequencies are sequentially transmitted to the receiving means. The frequency is supplied, and it is sequentially determined for each frequency whether or not a radio wave of the same frequency is used as a downstream radio wave from a peripheral radio base station. It is possible to accurately grasp the usage status of frequencies in peripheral base stations without requiring a mobile station, to be able to respond to changes in the situation adjacent to the base station autonomously, and to reduce the cost and size of the base station While being able to
Since it is performed during off-peak hours, there is little impact on services.

Further, according to the present invention, when the mobile station detects that the radio base station has stopped emitting radio waves, it activates the timer means, and during the counting operation of the timer means, stops the in-location switching operation. Since the suspension of the in-service area transition operation is canceled by expiration of the timer means or re-reception of the radio wave, the existing in-service area sequence can be used, and the hardware of the mobile station does not need to be changed, which is economical. Along with
Since it is performed during off-peak hours, there is little impact on services.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating configurations of a radio base station and a mobile station that implement a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment shown in FIG.

FIG. 3 is a diagram showing downlink broadcast information from a base station and a mobile station receiving operation for explaining a synchronous relationship between the base station and the mobile station during normal operation and electric field monitoring control in the embodiment shown in FIG. 1; is there.

FIG. 4 is a diagram illustrating an example of a traffic state in a wireless area.

[Explanation of symbols]

 1 Peripheral search frequency information table 2 Transceiver 3 Processing unit 4 Storage device 5, 10 Timer 8 Receiving unit 9 Processing unit 20 Base station 21 Mobile station

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-222596 (JP, A) JP-A-60-261233 (JP, A) JP-A-57-17246 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04B ⁷ /24-7/26 113 H04Q 7/06-7/38

Claims (2)

(57) [Claims] A plurality of wireless base stations form a wireless zone, and a plurality of mobile stations move within and between wireless zones to communicate with the base station, and the wireless base station communicates with its service area. A mobile communication system which constantly emits radio waves including information for notifying a mobile station of its presence while driving, wherein the wireless base station monitors traffic in a wireless area and detects a traffic off time zone. Traffic light off time detecting means, when the traffic light off time detecting means detects the traffic light off time zone, radio wave stopping means for stopping emission of the radio wave for a predetermined time, and uniformly radiating frequencies that can be emitted from the radio base station. A stored frequency information table, a receiving unit for receiving a downlink radio wave from a peripheral radio base station, and the emission of the radio wave is stopped for a predetermined time by the radio wave stopping unit. Then, during this predetermined radio wave suspension time, the frequencies stored in the frequency information table are sequentially read out, and the sequentially read out frequencies are sequentially supplied to the receiving means, and the radio waves having the same frequency as the frequency are read out. And a determination unit for sequentially determining whether or not is used as a downlink radio wave from a peripheral wireless base station for each frequency stored in the frequency information table. 2. The mobile station comprises: receiving means for receiving a radio wave from the radio base station; radio stop detection means for detecting that the radio base station has stopped emitting the radio wave by the receiving means; When the radio wave stop detecting means detects that the emission of the radio wave is stopped, a timer means for counting a time longer than the predetermined radio wave stop time; and while the timer means continues the counting operation, 2. The apparatus according to claim 1, further comprising: a stopover unit that stops the transfer operation, and a release unit that releases the stoppage of the transfer operation by expiring the timer unit or re-receiving the radio wave by the receiving unit. Mobile communication system as described.