JPH0211028A - System for deciding travel of mobile station among radio zones - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a control zone in which one control zone is configured by N wireless zones by N wireless base stations (N is an integer of 1 or more). The present invention relates to a mobile station inter-wireless zone transition determination method in which a mobile station detects and determines that a mobile station within the wireless zone has transitioned from one wireless zone to another wireless zone.

[Conventional technology]

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

In other words, there are N wireless base stations Ri (i=1.2...N) within one control zone as a service area, such as a car phone service, and the small radio base stations belonging to each base station Ri are The control zone is constituted by a collection of wireless zones. Each radio base station Ri is connected to a common radio control station l by a fixed transmission path.

The radio control station 1 is connected to a general telephone network via a mobile station (automobile) switching center (not shown).

In addition, the size of the small wireless zone belonging to each wireless base station Ri is determined to be wide enough to enable communication between the mobile station and the wireless base station based on the transmission power of the mobile station within the zone. It is being

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

In the figure, the signal configuration is composed of N radio base stations (R1 to R
N time slots S which are simultaneously transmitted by N ) and N time slots St which each radio base station transmits individually and sequentially.
(i=1.2...N) constitutes one frame, and such a frame is continuously repeated (hereinafter referred to as multiple station simultaneous/individual sequential transmission).

That is, in time slot S, each radio base station calls the mobile station at the same time in order to find out whether or not the mobile station is within the control zone, and when the mobile station responds, it indicates that the mobile station is within the control zone. If this is determined, it is determined which small radio zone the mobile station is in, and communication is performed between the radio base station and the mobile station that belong to the small radio zone.

A mobile station within the control zone that receives such a control channel detects the reception level of each individual time slot and finds the maximum reception level in each time slot that is above a certain value. It is known in which radio zone Rj (j is an integer from 1 to N) the mobile station is located. Knowing the individual transmission time slot in this way allows information on which radio zone the mobile station is in to be obtained from that slot, so it is no longer necessary to receive other individual transmission slots; In order to reduce power consumption, after detecting the time slot with the maximum reception level from among the N individual transmission time slots, the mobile station detects the time slot (S) in which N radio base stations simultaneously transmit and the maximum reception level. Only one time slot of individual transmissions indicating the level is intermittently received, and reception is not performed during unnecessary (N-1) individual transmission time slots, and some power in the mobile station is reduced accordingly. Just turn it off.

When a mobile station performing intermittent reception moves from one wireless zone to another, conventionally the determination of whether the transition has occurred is based on the individual transmission time slot being received. This was done by detecting that the reception level fell below a certain set value. but,
The reception level of individual transmission slots at zone boundaries is set as a target value at the time of system design, but it is greatly influenced by actual geographical conditions, building layout, etc., and is not constant, and the level at zone boundaries varies depending on the location. .

Therefore, if the setting level for determining that a transition has occurred (hereinafter sometimes simply referred to as transition determination) is set to a low boundary level, if a transition occurs between wireless zones with a high boundary level. Sometimes, the start of wireless zone reselection is delayed, and when a call is made or received, the wrong zone is used, which has a disadvantage that the system is adversely affected and the call is unsuccessful. Conversely, if the setting level is set to a high boundary level, when transitioning between wireless zones with a low boundary level, the zone transition judgment will occur significantly before reaching the zone boundary.
The zone is reselected, the previous wireless zone is reselected, the intermittent reception operation resumes, but the zone transition is immediately determined again, and the above operation is repeated, frequently comparing the reception levels of all individual slots. The disadvantage is that the power consumption of the mobile station increases.

The present invention has been made in order to eliminate the drawbacks of the prior art as described above, and therefore, an object of the present invention is to provide a movement system that prevents omissions in zone transition determination and eliminates wasteful power consumption. An object of the present invention is to provide a method for determining the transition between wireless zones of a mobile station in communication.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a single wireless zone with N wireless base stations (N is an integer greater than or equal to 1).
A control channel for paging is set between mobile stations and radio base stations within the control zone, and the signal configuration of the control channel is such that all radio base stations within the control zone A movement within a control zone in a situation consisting of a repetition of a first time slot in which simultaneous transmissions are made and a total of N time slots in which each radio base station transmits individually and sequentially. In the mobile station inter-wireless zone transition determination method, in which the mobile station detects and determines that the mobile station has transitioned from one wireless zone to another, all wireless base stations transmit at the same time. Measure the signal reception level in the first time slot and the signal reception level in the time slot corresponding to the wireless zone where the mobile station currently exists out of a total of N time slots in which transmission is performed individually and sequentially. However, it is determined that the mobile station has made a transition between wireless zones depending on the difference between the two levels.

[Effect]

The present invention determines whether a mobile station is moving between wireless zones in a system that employs simultaneous/sequential transmission from multiple stations as described above. This system compares the reception level of the time slots that are transmitted individually by the wireless base station that the station determines is in its area, and if the difference between the two times exceeds a certain value, it is determined that the station has moved between zones. , this is the most important feature. In conventional technology, the transition between zones is determined based on the absolute value of the reception level of the time slots that are transmitted sequentially by the radio base stations that are determined to be in the area of the mobile station. The difference is that the determination is made based on a value relative to the reception level in the time slot in which transmission is being performed.

〔Example〕

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

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

Although many signal lines are actually input/output to the input/output section 71 of the control section, only the signal lines for receiving data, receiving level, and power on/off pulse necessary for explaining the present invention are shown in this diagram. It is.

The functional operation of the mobile station is determined by a program stored in ROM 73. A program that implements the flowcharts described below is stored in the ROM 73. Furthermore, although it is related to the explanation below, the signal reception level determined by the mobile station is sent from the control unit 7 to the synthesizer unit 6.
The channel number of the paging control channel (P-ch) set between the mobile station and the radio base station is specified, and the reception level output from the receiving unit 4 is determined by the channel number. In addition, generation of timing depending on the data sequence of the control channel P-ch for multi-station transmission level measurement, individual transmission level measurement, intermittent reception, etc. By decoding, the timer 75 is started and generated.

FIG. 7 is an explanatory diagram showing an example of an incoming call control channel that employs time/individual sequential transmission between multiple 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 within the control zone simultaneously transmit radio waves, and 31 to SN are individual sequential transmission slots in which each base station individually and sequentially transmits radio waves. After receiving this incoming call control channel, the mobile station determines which base station it is visiting by comparing the reception levels of S1 to SN.

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 multi-station simultaneous transmission portion of S and the level of the individual transmission portion of Sj are compared.

The reception level where two wireless zones are in contact is shown in Figure 8.
As shown in the figure. Regarding the electric field level between base stations A and B, the level for the individual transmission part is a solid line, and the level for the multi-station transmission part is a combination thereof, as shown by a broken line.

At the zone boundary portion, the difference between the multiple station simultaneous transmission portion and the individual sequential transmission portion is 3 dB. Even if the reception level at the border is low (or high) due to the base station's overall transmission output being small or large, or due to geographical conditions, it may be difficult to reach the border under complex propagation conditions with terrain and buildings. This level difference is preserved even when the level is not constant.

As shown in FIG. 9, even if there is a difference in transmission output between radio base stations, the same conditions hold at boundaries a and b. Under such radio wave conditions, in a mobile station moving from base station A to B in Figure 8, the level of individual sequential transmission slots of base station A and the simultaneous transmission part of multiple stations are determined according to the flow in Figure 1. When the level difference is monitored, when the mobile station crosses the boundary C between base stations A and B, the level difference is 3.
dB, and by setting the determination threshold "L" to 3 dB, it is possible to quickly determine zone transition under various conditions as described above. When transferring between base stations C2D and E in FIG. 9, it is possible to determine transfer between base stations with different transmission outputs in exactly the same way.

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 in which N radio base stations simultaneously transmit, and Si (where i=1 to 6) is a time slot in which radio base station Ri transmits. When a mobile station is present at radio base station Ri, Si is most strongly affected in the slot of the individual transmission part. In FIG. 2, it will be observed that the most strongly affected St is just S3. In addition, 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 between ■ and ■ when the overall reception level is high, but the overall reception level is low. It will be recognized that the difference δ2 between the times ■ and ■ also hardly changes, but the absolute value of the reception level changes greatly between the cases ■ and ■.

To explain further, as shown in FIG. 2, the reception level changes slowly as the mobile station moves. Since the absolute level of the individual sequential transmission portions (slots ■ and ■ in the diagram) of the zone in which the user is located varies greatly, it takes time to improve measurement accuracy. However, in the method of the present invention, the multiple station simultaneous transmission part and the individual sequential transmission part are
, ■ slots or ■, ■ slots are measured almost simultaneously, so it is possible to accurately measure the level difference between the simultaneous transmission part of multiple stations and the individual sequential transmission part without being affected by fluctuations in the overall reception level. It is possible to obtain accurate measurements in a short measurement time, and it is possible to determine zone transition in a short time. In the example shown in the figure, the P-ch configuration is arranged so that a multi-station simultaneous transmission portion and an individual sequential transmission portion alternately exist for the most effect.

The above explanation was given for the case where two zones are in contact, but as shown in Figure 3, there is no difference in level at the point where three zones overlap, except that the level difference is about 4.8 dB (=101 og 3). The same can be said.

Furthermore, if the level difference is 10 logIIldB at a point where a plurality of zones (m-zones) overlap, it can be considered in exactly the same way.

〔Effect of the invention〕

As explained above, the present invention is a system that determines wireless zone transition based on the difference between the reception level of the simultaneous transmission part of multiple stations and the reception level of the individual transmission part. It is possible to judge transitions between zones without being affected by zone boundary levels that differ greatly depending on conditions such as transmission output, and has the advantage of improving the accuracy of transition judgments between zones. Since it is possible to reduce the number of times the reception levels of slots are compared and the radio zone is selected, this has the advantage of preventing an increase in power consumption in a mobile station that performs intermittent reception.

In addition, the level measurement of the simultaneous part of multiple stations and the simultaneous part of individual stations is as follows.
Since these are performed almost simultaneously, the level difference can be measured without being affected by the slow effects and zinc caused by the movement of the mobile station, which has the advantage of increasing the accuracy of zone transition judgment compared to the conventional method. Furthermore, since the number of operations for selecting a wireless zone can be reduced, there is an advantage in preventing an increase in power consumption in a mobile station that performs intermittent reception.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing the operation of an embodiment of the present invention, Fig. 2 is an explanatory diagram showing how the data reception level fluctuates as the mobile station moves, and Fig. 3 shows the three wireless zones. FIG. 4 is a conceptual diagram showing the configuration of a wireless zone in mobile communication; FIG. 5 is an explanatory diagram showing the signal configuration of a control channel for one frame in mobile communication; FIG. Figure 7 is a block diagram showing the circuit configuration of a mobile station, Figure 7 is an explanatory diagram of the signal configuration of a control channel in mobile communication and the related intermittent reception method, and Figure 8 shows the electric field level when two zones are in contact. Explanatory diagram, No. 9
The figure is an explanatory diagram of the electric field level when three base stations with different transmission outputs are lined up in a straight line. Explanation of symbols 1... Wireless base station, 2... Transmitting/receiving antenna, 3...
・Transmitter/receiver duplexer, 4...receiving section, 5...transmitting section, 6.
...Synthesizer Department, 7...Control Department Agent Patent Attorney Akio Namiki

Claims (1)

[Claims] 1) One control zone is composed of N radio zones with N radio base stations (N is an integer of 1 or more), and mobile stations and radio base stations within the control zone During this period, a control channel for paging is set up, and the signal configuration of the control channel consists of a first time slot in which all radio base stations within the control zone transmit simultaneously, and a first time slot in which each radio base station transmits individually and sequentially. Under a situation consisting of a total of N time slots in which transmission is performed, and the repetition of In the mobile station inter-zone transition determination method, the mobile station detects and determines the signal reception level in the first time slot in which all the radio base stations transmit simultaneously and the total N in which they transmit individually and sequentially. The signal reception level in the time slot corresponding to the radio zone in which the mobile station currently exists is measured, and the signal reception level in the time slot corresponding to the radio zone in which the mobile station currently exists is measured. A mobile station inter-wireless zone transition determination method characterized by determining that a transition has occurred.