JPS59178027A - Mobile radio communication system - Google Patents

Abstract

PURPOSE:To decrease the interference between radio zones without causing call loss by grouping a mobile station, dividing a transmission time of a call signal to the mobile station of each group at each group and retrieving a radio zone of an object zone at a time other than a call time of the own group. CONSTITUTION:A base station is arranged respectively at positions marked X and a radio zone is set at the surrounding of each base station. Each base station communicates as a rule with a mobile station in the own radio zone. The frequency for simultaneous call used for each base station to call a mobile station is assigned to a frequency different from simultaneous call areas A1, A2 and A3. Further, the simultaneous call is performed at the same time in common to the areas A1, A2 and A3. Moreover, the mobile station is divided into plural number of groups. The simultaneous call is performed while being added with a group number respectively at a time different from each group.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to a mobile radio communication system that is similar to an automobile radio communication system, and is a mobile radio communication system that automatically selects an optimal base station with which a mobile station should communicate. Regarding the method of

[Description of prior art]

A Zahis area is defined within the range in which a large number of mobile stations can move, a large number of base stations are placed within that service area, a wireless zone is set up for each base station, and communication is performed with mobile stations within that wireless zone. Is it known how the system is structured? In order to move from a base station and send out a station, perform a paging at the paging frequency assigned to each base station, and then
The system is configured to specify the number of a specific mobile station in a general paging and prompt that mobile station to respond. - In principle, the same paging frequency is assigned to multiple adjacent base stations (1), and which base station to communicate with among the multiple adjacent base stations is determined based on the response from the mobile station. The base station determines and sets based on the signal.

The mobile station automatically selects a group of base stations with which it should communicate by determining the magnitude of the reception level of the paging frequency. In a specific example, when a mobile station turns on the power, it sequentially switches and receives all paging frequencies and detects the reception level.
Identify the paging frequency that is received at the highest level,
It is determined that there is one in the paging area of a group of base stations using that frequency.

In this method, if the mobile station moves beyond the paging area after power is turned on, other measures are required. For example,
If the level of the received paging frequency falls below the specified value, it is determined that the mobile stations are moving out of their respective paging areas, and at that point all The system sequentially receives the broadcast paging frequencies, selects the broadcast paging frequency that is received at the highest interrogation level, and resets the base station with which to communicate.

Although this method is generally good, imperfect operation may occur due to facing, which is unique to mobile communications. For this reason, if the specified value for level judgment is set high, the level will frequently be judged to be below the specified value when entering the zone from the periphery of the zone, and as a result, all paging frequencies will be below the specified value. This may result in an erroneous determination that there is no base station to communicate with, or the search time for a paging frequency may become longer.

In this case, the mobile station becomes uncontrollable from the base station, and incoming and outgoing calls during this time have the drawback of being lost. In order to avoid this, the above-mentioned drawbacks can be solved by lowering the specified value for level judgment, or conversely, it is determined that there is no level deterioration even though the mobile station is in a regionally different paging area. Misidentification may occur if the user is located in the previous paging area. In this case, the paging areas actually overlap, and if a mobile station is located within one area of the overlap, the actual location of the mobile station and the registered area of the base station will be different. In addition to the second problem of "services", interference with other areas increases, and frequency allocation cannot be carried out effectively.

As an example of other countermeasures, is there a method to search for all broadcast paging frequencies at regular intervals regardless of the reception level of the broadcast paging frequencies? In this case, too, the search time is long, which is a drawback that could lead to call loss. There is.

[Purpose of the invention]

The present invention solves these drawbacks, and aims to provide a mobile radio communication system that does not cause calls 11 and has little interference between radio zones.

[Features of the invention]

In the present invention, mobile stations are divided into a plurality of groups in advance from the time of joining, and the base station performs the above-mentioned simultaneous paging by assigning a group number to each group at a different time. When a general paging of a group to which the mobile station belongs is performed, the mobile station detects whether or not its own number is included in the general paging, or detects whether or not the mobile station's own number is included in the general paging, or calls a group other than the group to which the mobile station belongs. Since the control device is idle during the time when paging is being carried out for each paging frequency, the control device uses this time to determine the optimal base station or base station to communicate with by detecting the reception level for each paging frequency. It is characterized in that it is configured to select a base station group.

[Explanation based on examples]

FIG. 1 is a conceptual diagram of a service area S in which the mobile radio communication system of the present invention is implemented. A base station is placed at each position indicated by X in FIG. 1, and a wireless zone Z is set up around each base station. In principle, each base station communicates with mobile stations within its own wireless zone. A base station performs paging to call mobile stations. - Broadcast paging is performed using the mass paging frequency, but if the mass paging frequency is
Different frequencies are assigned to each of A1, A2, and A3.

What's more, this is the simultaneous call area: A1, A2, A
3. Do this at the same time.

The first feature of the present invention is that each mobile station is divided into a plurality of n groups. The group to which a mobile station belongs is fixedly set from the time the mobile station joins this mobile radio communication system, and cannot be changed over time or as the area moves within the service area. do not have.

The second feature of the present invention is that - simultaneous calling is performed for each group at different times, with group numbers assigned to each group.

Furthermore, the third feature lies in the configuration of mobile stations; when each mobile station receives a paging, when the paging of the group to which the mobile station belongs is being carried out, the mobile station is It detects whether the mobile station number is included or not and prepares for a call response for its own station, but at the time when a group other than the group to which the mobile station belongs is being called, - general paging is performed. The paging frequency of each base station is sequentially selected and received, and the reception level of the paging frequency is detected. Then, the base station or base station group transmitting the broadcast paging frequency that can best be received is selected as the base station or base station group with which communication should be set up next.

For example, when a mobile station is in paging area Δ1, the base station in this example controls which base station to communicate with. Zunai, -
When the mobile station detects that its own number is included in the paging signal transmitted by the base station in paging area A1, the mobile station responds according to a predetermined procedure, or this response signal is received simultaneously by multiple base stations. Detect the reception level of the response signal. The levels received by each base station are compared with each other via wired lines, and the base station that detects the highest reception level establishes communication with the mobile station, assuming that the mobile station is in its own wireless zone.

FIG. 2 is a signal time chart 1- transmitted on the paging frequency according to the embodiment of the present invention. At time T1, paging signals 10 to 12 for mobile stations in the first phase are transmitted. At time T2, paging signals 13 to 15 for mobile stations in the second group are transmitted. paging signals 16 to 18 are transmitted to the mobile stations of the n-th group.This is repeated.FIG.
) shows a configuration example of the timeout. Calling (No. g has a configuration including Scoot No. 3 No. 19, Group No. 20, and Mobile Station No. 2I.

The mobile station receives all broadcast paging frequencies with hl11 switching during times other than when paging for its own group is being performed, and detects and stores the reception level.

Select the paging frequency with the highest level.

If this paging frequency is the same as the paging frequency received before the start of switching, the next self-group paging signal is received at the original paging frequency after waiting for the timer to time out. If this is the same as the paging frequency before switching, it switches to the paging frequency that was received at the highest level, and registers the location to the base station that it is in the wireless zone that uses that paging frequency. From then on, standby calls will be received on this paging frequency.

FIG. 4 is a flowchart 1- showing the control procedure of the mobile station.

The time τ is selected to be equal to or smaller than the time T2+T3+...+Tn in FIG. If there is a difference in the ringing time of each group between different paging frequencies, the mobile station needs to detect the period of its own group paging when switching the paging frequency. Wait until a calling signal can be received, and if it is received, repeat the above operation.

FIG. 6 is a diagram showing an example of the configuration of a portion related to simultaneous paging of the base station apparatus according to the embodiment of the present invention. The main control unit 25 in the central control station 22 sends and receives control signals to and from mobile stations and executes control. The paging signal from the main control unit 25 is distributed by a distributor 26 to a number equal to the number n of groups of mobile stations. The decoder 27 decodes the group number of each paging signal, and if it is a signal of the first group, then
is opened and the signal is input into the waiting circuit 29 and stored. As shown below by dotted lines in the figure, the paging signal for the second group is stored in the waiting circuit 29 of the second column, and the paging signal of the first group is stored in the waiting circuit 29 of the r)th column.

The timing generation circuit 30 is shown in FIG. A pulse is supplied to the waiting circuit 29 of the first column, and the first
While the queue queuing circuit 29 is being supplied with pulses,
The stored paging signal is sent to the signal synthesis circuit 3j. If there is no stored paging signal, no signal is sent. Similarly, the waiting circuit 29 in the second column is supplied with the pulse at time T2 (=this pulse), and the waiting circuit 29 in the last n-th column is supplied with a pulse at Tn. The waiting circuit 29 sends out the stored paging signal to the signal synthesis circuit 31 in the same manner as above while the pulse is being supplied.

In this way, the output of the signal synthesis circuit 31 is a signal aligned to the unique transmission timing for each group of mobile stations, and a paging signal shown in FIG. 2 is obtained.

The output of the signal combining circuit 31 is further distributed by a distributor 32 to a number equal to the number of wireless base stations Q, and is distributed to the wireless base stations 23 to 23.
24. At the radio base station, the paging channel transmitter 33, duplexer 34, and antenna 35 transmit this signal to the mobile station. An antenna 35 and a duplexer 34 for responding to a paging signal from a mobile station.
The signal is then received and demodulated by the paging frequency receiver 36 and transmitted to the central control station 22.

FIG. 6 is a diagram showing an example of the configuration of a mobile station according to an embodiment of the present invention. The signal from the base station is transmitted through the antenna 37 and the duplexer 3.
8. The signal is supplied to the control unit 42 via the receiver 39. The local oscillator signal for receiver 39 is supplied from synthesizer 40 . The oscillation frequency of the synthesizer 40 is specified by the control unit 42. When transmitting a signal from the mobile station, the signal from the control unit 42 is modulated by the transmitter 41 and transmitted to the base station via the duplexer 38 and the antenna 37. Transmitter 4
One local oscillation signal is supplied from a synthesizer 40 .

The control unit 42 stores the control procedure for the mobile station, and decodes all received signals and encodes all transmitted signals. The control unit 42 is composed of a processor, a memory for continuous output, and a continuous write memory, and stores control procedures in the memory for continuous output, and also records the reception level. = etc. are performed by reading/writing memory.

The reception level is detected by envelope detection of the intermediate frequency signal from the receiver 39 by a detector 44, and the detected signal is supplied to the control section 42. The control unit 42 can be configured to perform memory and average ring operations for each channel.

In the example shown in Fig. 4, all paging frequencies are sequentially switched while only those in the group other than the own group are being called, and the paging frequency with the highest reception level is determined. Receive multiple cycles in which calls are being made from groups other than your own group, perform the level detection described above for each of these multiple times, calculate the average of the reception levels for each of the multiple call frequencies, and find the best one. The paging frequency that can be received in the state of l,''12,'-f'+x・
・It is. During the first cycle of 1.21 to 1.pi.1, all paging frequencies are sequentially switched, and their levels are received, detected, and stored. - The number of general calling frequencies is M, and the receiving bells of each - general calling frequency are ■, 11, L2.
1...L? Let it be rL1. The next cycle T22~T
Similarly, during the nz period, the paging frequency is sequentially switched and the level is memorized, and this is sent to l512, L22...I-m.
Set it to 2.

The mobile station repeats this three times, for example, and receives 1/3 (L1'l+L12+L13) and 1/3 (L1'l+L12+L13) for each paging channel.
21+L22+L23), 1/3 (L7) (I
+LH2+Lm3), the maximum one is specified, and the paging frequency having the maximum value is selected, and for standby, the receiving frequency is switched to this base station and the location is registered.

In the above example, all paging frequencies are sequentially switched during one cycle, and levels are detected for all frequencies. A method may also be adopted in which the levels are detected by sequentially switching the frequencies, and by using a plurality of cycles, all paging frequencies are switched and received, and the levels are detected.

In addition, although the explanation has been given using the case where a plurality of wireless zones exist in the paging area, the present invention can be applied even if the paging area includes only a single wireless zone, that is, the wireless zone and the paging area coincide. Is possible.

The present invention is applicable even if the paging frequency matches the communication channel.

Furthermore, in the above example, the frequency at which mobile stations are paged within the paging area, that is, the general paging frequency is described as a single frequency, but it is also possible, for example, that the general paging frequency is different for each radio zone.

In this case, the paging frequency is newly specified each time the radio zone is changed, but the only difference is that the location registration is performed only when changing the area, and the present invention can be similarly applied. Possible. In this case, the present invention is also applicable to the case where there is only one paging area within the service area.

[Explanation of effects]

As explained above, the mobile stations are divided into sections, the time for sending out paging signals to the mobile stations in each group is divided into groups, and the wireless zone in which the mobile station is located is searched for at a time other than the paging time of the own group, so the mobile station can be controlled. The device operates efficiently. Therefore, call losses are less likely to occur, and it is possible to detect the wireless zone in which the mobile phone is located more frequently.

In addition, since radio frequency detection is performed more frequently, the overlap of designated frequency areas becomes shallower, making it possible to correctly detect increases in locations close to the boundaries of regular radio zones, which improves frequency utilization efficiency. There is.

[Brief explanation of drawings]

FIG. 1 is a shield diagram of a service area in which the present invention will be implemented. FIG. 2 is a time chart showing an example of sending out a paging signal at a paging frequency. FIG. 3 is a diagram showing an example of the format of a calling signal. FIG. 4 is a flowchart showing the control operation of the mobile station. FIG. 5 is a block diagram of a part related to simultaneous paging of a base station according to an embodiment of the present invention. FIG. 6 is a diagram showing the configuration of a mobile station according to an embodiment of the present invention. FIG. 7 is a time chart showing another example of sending out a paging signal at the paging frequency. 10-18... Calling signal, 19... Start code,
2o...Group number of the calling mobile station, 2]...Number of the calling mobile station, 22...Central control station, 23.24...Radio base station, 25...Main control unit, 26. ...Distributor, 27
... Decoder, 28 ... Kate, 29 ... Queue circuit, 30 ... Timing generation circuit, 31 ... Combiner, 32 ... Distributor, 33 ... - General paging channel transmitter , 34... Transmitter/receiver duplexer, 35... Antenna,
36... - paging channel receiver, 37... antenna, 38... duplexer, 39... receiver, 40...
...Synthesizer, 41...Transmitter, 42...Control unit, 43...Telephone, 44...Detector. Patent Applicant Nippon Telegraph and Telephone Public Corporation Agent Patent Attorney Takaatsu Ide 1 Figure □ Erase time? Figure 9 3 Figure

Claims (1)

[Claims] (1) A plurality of base stations are installed within the movable range of a large number of mobile stations, a wireless zone is set up for each base station within a range where good communication can be established with the mobile stations, and each of one or more of the base stations is A unique paging frequency is assigned to each mobile station, and mobile stations simultaneously paging multiple base stations in adjacent wireless zones. In a mobile radio communication system in which each mobile station selects a paging frequency that can be strongly received in the area in which it is moving, and selects a base station with which the mobile station should communicate, the mobile station is It is divided into multiple groups in advance, and the base station performs the above-mentioned simultaneous paging by assigning a group number to each group at a different time, and the mobile station performs the simultaneous paging for groups other than the group to which the mobile station belongs. 1. A mobile radio communication system characterized in that the optimum base station with which to communicate is selected by detecting the reception level for each general paging 1i,'] wave number during the time when the mobile radio communication system selects the optimum base station with which to communicate.