JPH0683136B2 - Mobile station wireless zone transition determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention configures one control zone by N wireless zones of N wireless base stations (N is an integer of 1 or more) The present invention relates to a mobile station wireless zone transition determination method in which a mobile station inside the mobile station detects that the mobile station has transitioned from a certain wireless zone to another wireless zone.

[Conventional technology]

FIG. 4 is a conceptual diagram showing a configuration of a wireless zone in mobile communication such as a car telephone.

That is, for example, N radio base stations are provided in one control zone as a service area such as a car telephone service.
Ri (i = 1, 2 ... N), and the control zone is constituted by a set of small radio zones belonging to each base station Ri. Each radio base station Ri is connected to the common radio control station 1 by a fixed transmission path.

The radio control station 1 is connected to a general telephone line network through a mobile station (automobile) switching station (not shown). Also, the size of the small radio zone belonging to each radio base station Ri is determined to be a size that enables sufficient communication between the mobile station and the radio base station due to the transmission power of the mobile station in the zone. Has been.

FIG. 5 is an explanatory view showing the signal structure of a control channel for calling a mobile station in mobile communication for one frame.

In the figure, the signal structure of the N radio base stations (R1~R _N)
Are simultaneously transmitted by the wireless base station and N time slots Si (i = 1,2 ...
... N) is defined as one frame, and such a frame is continuously repeated (hereinafter, multiple stations simultaneously /
Individually called sequential transmission).

That is, in the time slot S, each radio base station calls the mobile station at the same time in order to know whether or not there is a mobile station in the control zone, and there is a response from the mobile station to stay in the control zone. If this is known, it is checked which small wireless zone the mobile station is in, and communication is performed between the wireless base station and the mobile station belonging to the small wireless zone.

A mobile station within the control zone that receives such a control channel shall detect the reception level of each individual time slot and find the maximum reception level of each time slot above a certain value. The radio zone Rj (j is an integer not less than 1 and not more than N) in which the own mobile station is known is known. By knowing the time slot for individual transmission in this way, information about which radio zone the mobile station is in can be obtained from that slot, so it is no longer necessary to receive other slots for individual transmission, and the mobile station After detecting the time slot of the maximum reception level from the time slots of the N individual transmissions to reduce the power consumption, the mobile station receives the time slot S simultaneously transmitted by the N radio base stations and the maximum reception level. Only one time slot of individual transmission indicating the level is intermittently received, and no unnecessary (N-1) time slots of individual transmission are received, and a part of the power supply in the mobile station is reduced by that amount. Just turn it off.

When a mobile station performing such an intermittent reception operation shifts from a certain wireless zone to another wireless zone, conventionally, the determination that the shift has been made is determined by the received individual transmission time slot. It was performed by detecting that the reception level fell below a certain set value. However, the reception level of the individual transmission slot at the zone boundary is set to a certain value at the time of system design, but it is not constant because it is greatly influenced by the actual geographical conditions, the layout of buildings, etc. Depends on

For this reason, when the set level for determining that the transition has been performed (hereinafter, may be simply referred to as transition determination) is set to the low boundary level, the wireless zones that have the high boundary level are transitioned. Sometimes, when the start of reselection of a wireless zone is delayed and an incoming / outgoing call is made, the wrong zone is used, and the system is adversely affected, and the outgoing / incoming call fails. Conversely, when the setting level is set to a high boundary level, and when moving between wireless zones with a low boundary level, the zone transition judgment occurs significantly before reaching the zone boundary, and the zone reselection is performed and the previous wireless zone is reached. Then, the intermittent reception operation is performed again, but the zone transition is determined again immediately, and the above operation is repeated, and the operation of comparing the reception level with all individual slots is performed in a complicated manner, and the power consumption of the mobile station is reduced. There are increasing drawbacks.

The present invention has been made to eliminate the above-mentioned drawbacks of the prior art. Therefore, an object of the present invention is to prevent leakage of zone transition determination and to reduce waste of power consumption. An object of the present invention is to provide a method for judging the transition between wireless zones of mobile stations in communication.

[Means for Solving the Problems]

To achieve the above object, in the present invention, one N wireless zone is used by N wireless base stations (N is an integer of 1 or more).
A control channel for calling is set between the mobile station and the radio base station in the control zone, and the signal configuration of the control channel is set by all radio base stations in the control zone. A mobile station within a control zone under the condition that it is configured by repeating a first time slot for transmitting at the same time and a total of N time slots for sequentially transmitting individually by each radio base station. In the mobile station wireless zone transition determination method in which the mobile station detects that the mobile station has moved from one wireless zone to another wireless zone, all wireless base stations of the mobile station transmit simultaneously. The signal reception level in the first time slot and the time slot corresponding to the radio zone in which the mobile station is currently located, out of a total of N time slots that are individually and sequentially transmitted. And the signal reception level of each mobile station are measured, and it is decided that the mobile station has made the transition between the radio zones depending on the difference between the two levels.

[Action]

The present invention provides a determination of the transition between radio zones of a mobile station in a system that employs the above-described simultaneous / individual multiple station transmission, the reception level of the multiple station simultaneous transmission portion of the incoming control channel being received, and the mobile station. Is compared with the reception level of the time slots that are sequentially transmitted by the wireless base stations that are determined to be in the range, and if the difference exceeds a certain value, it is determined that the zone transition has been made. This is the main feature. In the conventional technology, the transition between zones is determined by the absolute value of the reception level of the time slots that are sequentially transmitted by the wireless base stations that the mobile station determines to be in the service area. The difference is that the determination is made based on the relative value to the reception level in the time slot in which transmission is performed.

〔Example〕

First, the circuit configuration of the mobile station used in the present invention will be described.

FIG. 6 is a block diagram showing a circuit configuration of such a mobile station. As is clear from the figure, the mobile station is the transmitter 5,
Receiving unit 4, synthesizer unit 6, antenna 2, duplexer 3,
The control unit 7 includes a CPU 72, a ROM 73,
It is composed of a RAM 74, a timer 75, an input / output unit 71, and a clock generator 76.

Although many signal lines are actually input / output to / from the input / output unit 71 of the control unit, in this figure, the received data necessary for explaining the present invention,
Only the signal lines for the reception level and the power on / off pulse are shown.

The functional operation of the mobile station is determined by the program stored in the ROM 73. A program that realizes a flowchart described below is stored in the ROM 73. Further, although related to the description below, the signal reception level determined by the mobile station is transmitted from the control unit 7 to the synthesizer unit 6 to the paging control channel (set between the mobile station and the radio base station). This is the reception level output from the receiving unit 4 by designating the channel number of P-ch). Further, for generation of timing depending on the data sequence of the control channel (P-ch) such as multi-station transmission partial level measurement, individual transmission partial level measurement, and intermittent reception, the reception data output from the reception unit 4 is used for the control unit 7. By deciphering in, the timer 75 is activated and generated.

FIG. 7 is an explanatory diagram showing an example of an incoming call control channel adopting simultaneous / individual sequential transmission of a plurality of stations which is a premise of the present invention. In the figure, S is a multi-station simultaneous transmission slot in which all base stations in the control zone simultaneously transmit radio waves, and S1 to SN are individual sequential transmission slots in which each base station individually and sequentially transmits radio waves. After receiving the incoming control channel, the mobile station compares the reception levels of S1 to SN to determine the base station in which it is located. After that, intermittent reception as shown in the figure is possible. In this example, it is determined that the reception level of Sj is the highest.

In this intermittent reception, the reception level of the S multi-station simultaneous transmission part of S and the level of the individual transmission part of Sj are compared.

No. 8 shows the reception level where two wireless zones are in contact
Shown in the figure. As for the electric field level between base stations A and B, the level of the individual transmission part becomes a solid line, and the transmission part of multiple stations becomes a combination of them.
It is as shown by the broken line. At the zone boundary, the difference between the multiple station simultaneous transmission part and the individual sequential transmission part is 3 dB. Even if the transmission output of the base station is small or large as a whole, or if the reception level at the boundary is low or high due to geographical conditions, etc., the boundary level is high in complex propagation conditions with topography and buildings. This level difference is preserved even when V is not constant.

As shown in FIG. 9, even when there is a difference in transmission output between radio base stations, the same conditions are satisfied at boundaries a and b. Under such radio wave conditions, base stations A to B in FIG.
In the mobile station moving to, according to the flow of FIG.
If the level of the individual sequential transmission slot of the base station A and the simultaneous transmission part of multiple stations are determined and the level difference is monitored, when the mobile station crosses the boundary C between the base stations A and B, the level difference becomes 3 dB, and If the threshold value "L" is set to 3 dB, zone transition can be promptly determined under the various conditions described above. When the base stations C, D, E shown in FIG. 9 are transferred, the transfer determination between the base stations having different transmission outputs can be performed in the same manner.

FIG. 2 is an explanatory diagram showing how the data reception level fluctuates as the mobile station moves.

In the figure, S is a time slot transmitted by N wireless base stations at the same time, and Si (where i = 1 to 6) is a time slot transmitted by the wireless base station Ri. When the mobile station exists in the radio base station Ri, Si receives the strongest in the slot of the individual transmission part. It can be seen in Figure 2 that the most strongly received Si is just S3. The difference between the data reception level of the multi-station simultaneous transmission part S and the data reception level of the individual transmission part S3 is the difference δ1 when the reception level is high overall, and the difference δ1 when the reception level is low overall. It will be appreciated that the difference δ2 between the two signals is almost the same, but the absolute value of the reception level is significantly different between the two signals.

Further adding the explanation, as shown in FIG. 2, the reception level slowly changes as the mobile station moves. Since the absolute level of the individual sequential transmission part (slot in the figure) of the existing zone changes greatly, it takes time to improve the measurement accuracy. However, in the system of the present invention, the multiple station simultaneous transmission part and the individual sequential transmission part are measured almost at the same time as the slot of or the slot of in the figure, and therefore are affected by the fluctuation of the overall reception level. It is possible to accurately determine the level difference between the multiple station simultaneous transmission portion and the individual sequential transmission portion with high accuracy, and it is possible to determine the zone shift in a short time. In the example in the figure, the P-ch configuration is arranged so that the multiple station simultaneous transmission part and the individual sequential transmission part are alternately present so as to be most effective.

The above explanation has been made on the case where the two zones are in contact with each other, but it is exactly the same except that the level difference is about 4.8 dB (= 10 log 3) at the point where the three zones overlap as shown in FIG. Conceivable.

Furthermore, even at a point where multiple zones (m zones) overlap, if the level difference is 10 logm dB, it can be considered exactly the same.

〔The invention's effect〕

As described above, the present invention is a method of determining the transition of the wireless zone based on the difference between the reception level of the multi-station simultaneous transmission part and the reception level of the individual transmission part. Depending on the conditions such as the transmission output, it is possible to judge the transition between zones without being affected by the zone boundary levels that are greatly different, and there is an advantage that the accuracy of the transition judgment between zones can be improved. Since it is possible to reduce the number of times of performing the operation of selecting the radio zone by comparing the reception levels of the slots, there is an advantage of preventing an increase in power consumption in a mobile station performing intermittent reception.

In addition, the level measurement of multiple stations simultaneous part and individual simultaneous part,
Since they are performed almost at the same time, the level difference can be measured without being affected by the slow fading caused by the movement of the mobile station, which has the advantage of improving the accuracy of zone transition determination more than before, and also selects the wireless zone. Since the number of operations to be performed can be reduced, there is an advantage of preventing an increase in power consumption in a mobile station performing intermittent reception.

[Brief description of drawings]

FIG. 1 is a flowchart showing the operation of one embodiment of the present invention, FIG. 2 is an explanatory view showing how the reception level of data fluctuates as the mobile station moves, and FIG. 3 shows three wireless zones. FIG. 4 is a plan view of the arrangement of wireless zones in contact with each other, FIG. 4 is a conceptual diagram showing a configuration of a wireless zone in mobile communication, FIG. 5 is an explanatory diagram showing a signal configuration of a control channel in mobile communication for one frame, and FIG. FIG. 7 is a block diagram showing a circuit configuration of a mobile station, FIG. 7 is an explanatory diagram of a signal configuration of a control channel in mobile communication and an intermittent reception system related thereto, and FIG. 8 is an explanatory diagram of an electric field level when two zones are in contact with each other. , FIG. 9 is an explanatory diagram of an electric field level when three base stations having different transmission outputs are arranged in a straight line. Explanation of reference numerals 1 ... Radio base station, 2 ... Transmission / reception antenna, 3 ... Transceiver, 4 ... Reception unit, 5 ... Transmission unit, 6 ... Synthesizer unit, 7 ... Control unit

Claims (1)

[Claims] 1. A control zone is constituted by N radio zones of N radio base stations (N is an integer of 1 or more), and between a mobile station and a radio base station in the control zone. A control channel for calling is set, and the signal configuration of the control channel is such that the first time slot in which all the radio base stations in the control zone simultaneously transmit, and each radio base station individually and sequentially transmits. Under the condition that it is configured by repeating N timeslots in total, a mobile station in the control zone detects that the mobile station has moved from one radio zone to another radio zone. In the mobile station wireless zone transition determination method, the mobile station concerned receives the signal reception level in the first time slot in which all the wireless base stations transmit at the same time, and the total of sequentially transmitting individually. The signal reception level in the time slot corresponding to the radio zone in which the mobile station currently exists among the N time slots and the signal reception level are measured, respectively, and the mobile station is dependent on the difference between the levels, and The mobile station wireless zone transfer determination method characterized by determining that the transfer has been performed.