JPH0667008B2 - Mobile station position detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention measures the reception level of a transmission wave of a mobile station at each base station in a mobile communication system having a small radio zone configuration in which the same frequency is repeatedly used. , When determining the wireless zone where the mobile station is located, to prevent erroneous reception level measurement caused by interlaced propagation from other wireless zones using the same channel, the channel voice band in use for each repeated zone The present invention relates to a mobile station position detection method for transmitting an identification code outside.

[Prior Art] FIG. 1 is a diagram showing a concept of a wireless zone configuration in a mobile wireless system.

In FIG. 1, 1 is a service area, which can be a nationwide scale in public mobile radio. 2A-2C
(Hereinafter generally referred to as “2”) is a repetitive zone, and the service area 1 is an area relatively close to the same radio frequency in order to effectively use the radio frequency and economic efficiency of the system. It is covered by the repeat zone 2 which is repeatedly used in. Each repeating zone 2 is composed of a plurality of wireless zones 3, and each wireless zone 3 is determined to have a sufficient communication area by the transmission power of the mobile station. One or a plurality of channels (radio frequencies for communication) are arranged in each radio zone 3.

Reference numeral 4 denotes a base station installed in each wireless zone 3, 5 a control station installed in each repeating zone 2, and the control station 5 collectively controls the inside of the repeating zone 2. Are usually connected by a fixed line.

In some cases, unlike the model shown in FIG. 1, a plurality of repeating zones may be collectively controlled, or the control station may be arranged so that the repeating zones are divided and controlled.

Next, the arrangement of channels in each wireless zone will be described.

In principle, different channels are arranged in each wireless zone 3. However, in order to effectively use the radio frequency, the same radio frequency is repeatedly used. For example, in the model of FIG. ₁ , all the channels used in a plurality of wireless zones 3 (identified by the symbols A ₁ , A ₂ , and A ₃ in the figure) in a specific repeating zone 2A are different. ,
In many cases, the channel used in the wireless zone of A _{1 and} the wireless zone belonging to another repeating zone, for example, the channels used in B ₁ and C ₁ are the same.

In addition, A ₂ , B ₂ , and C ₂ wireless zones and A ₃ and B
_The channels used in the wireless zones _{3 3} and C ₃ are often the same.

Thus, in general, each repeating zone 2 is composed of a plurality of radio zones 3 in which the same channel is arranged for each repeating zone, and by repeatedly using this repeating zone, It usually covers the service area 1.

Next, a general example of processing when a mobile station in a call moves to a wireless zone will be described.

Since the channels used are different between adjacent wireless zones, when the mobile station moves to another wireless zone during a call, it is necessary for the base station to detect this and switch to the new wireless zone. .

If this channel switching is not performed correctly and the wireless channel is used outside the original zone, the propagation loss will increase and the quality of the call will deteriorate. It will give interference. A conventional mobile station position detecting method for detecting the time when this switching is performed, that is, the mobile station has moved to the wireless zone will be described below.

FIG. 2 is a diagram for explaining the processing of the conventional mobile station position detection system, and focuses on the wireless zones A ₁ , A ₂ , A ₃ and B ₁ of FIG.

As described above, different channels are used for A ₁ , A ₂ , and A ₃ , but the same channel is used for A ₁ and B ₁ .

As shown in FIG. 2, the mobile station 6A is now in the wireless zones A ₁ to A.
Consider the case of traveling to ₃ . Mobile station 6A initially communicates with the base station of A ₁ . The reception level of the channel ₁ used by the mobile station 6A is measured at each base station in the radio zones A ₁ , A ₂ , and A ₃ , and the levels are compared by the control station 5 to the reception level of the base station of A _1. When the reception level of the base station of A ₃ becomes higher than that of the mobile station 6 A, it is determined that the mobile station 6 A has moved from the wireless zone A ₁ to A ₃ , and the channel used by the mobile station 6 A is allocated to the wireless zone A _1. Channel
Channel ₃ arranged from ₁ to the radio zone A ₃
Then, the mobile station 6A starts communication with the A ₃ base station. By such control, the mobile station 6A can always continue communication with the closest base station.

[Problems to be solved by the invention]

In the conventional mobile communication system as described above, monitoring is performed by measuring only the reception level of the channel used by the mobile station at each base station, so that, for example, in the wireless zone B ₁ as shown in FIG. Same channel as A _1
If there is a mobile station 6B that uses ₁ and receives ₁ at the boundary with the wireless zone A ₂ , the base station of A ₂ receives the reception level of channel ₁ transmitted by the mobile station 6B and the mobile station 6A. However, there is a problem in that the control station 5 may erroneously determine that the mobile station 6A is moving to the wireless zone A ₂ because it cannot distinguish the reception level of the channel ₂ transmitted by the mobile station 6A.

In view of such conventional problems, the present invention provides a mobile station position detection method that does not affect reception level measurement at other base stations between radio zones that use channels of the same frequency. Has an aim.

[Means for solving problems]

According to the invention, the above object is achieved by means of the patent claims.

That is, the present invention is characterized mainly in that the mobile station transmits the identification code of the repetitive zone outside the voice band of the used channel during communication, and the conventional technique is the measurement channel of the base station. Even if the reception level is high, if the identification code received outside the voice band is different from the identification signal of the channel used by the mobile station being measured, the reception level is invalid and only if the identification codes match. The difference is that the measured reception level is valid.

[Embodiment] FIG. 3 is a diagram for explaining the processing of the mobile station position detection system according to an embodiment of the present invention. As with FIG. 2, the mobile station 6A shifts from the wireless zone A ₁ to A ₃ . It shows the case.

In the embodiment of the present invention, the mobile station transmits the identification code of the repeating zone to which the base station in communication outside the voice band of the transmitting channel belongs. (Mobile station calling or called or the location registration, it is possible to know the repetitive radio zone serving self by the information of the control channel during such channel switching) the mobile station 6A of Figure 3 is the radio zone A ₁ outside voiceband channel ₁ since the communication with the base station identification code
(a) has been sent. In addition, the mobile station 6B communicating with the base station in the wireless zone B _{1 having} a different repeating zone is
The same channel ₁ as 6A is used, but a different identification code (b) is transmitted.

Also, when measuring the reception level of channel ₁ , the base station simultaneously receives the identification code transmitted outside the voice band,
In addition to the value of the reception level, the control station 5 is also notified of the identification code. The control station 5 determines the position of the mobile station 6A by comparing the magnitudes of the reception levels related to the channel ₁ notified from each base station. At this time, it is added to the reception level. When the identification code is different from that of the channel in which the mobile station 6A is currently communicating, the reception level is ignored.

By performing such processing, for example, in the base station of the wireless zone A _{2 in} FIG.
Even if the channel ₁ (b) of B is received and notified to the control station 5, the control station 5 can know from the identification code that this reception level is due to another mobile station.
Since the channels of the same frequency are not assigned to different mobile stations within the same repetition zone, correct mobile station position detection can be performed.

Here, a method of signal transmission outside the voice band will be described.

FIG. 4 shows an example of the distribution of the used frequency band of the wireless channel, where 8 is a communication voice band and 7 or 9 is a band for transmitting an identification code.

A control signal can be transmitted even during a call by providing a signal transmission band above or below the voice band as shown in the figure, and separating each by a filter on the receiving side.

FIG. 5 shows an example of a time chart of control signal transmission outside the voice band, in which 10 is an identification code and 11 is another control signal. As shown in the figure, it is not necessary to transmit the identification signal all the time, and it is sufficient that at least one identification signal can be received within the measurement unit time of the reception level.

As another embodiment of the present invention, instead of the identification code by the digital signal in the above embodiment, the communication voice band 8 as shown in the channel use frequency band distribution diagram of FIG. 6 is used.
Besides, as the identification code 12, tones a, b having different frequencies,
It is also possible to adopt a method of arranging c ... And assigning it to each repeating zone and performing the same processing as in the above-mentioned embodiment.

〔The invention's effect〕

As described above, according to the method of the present invention, the identification code for each repetitive zone is added to the outside of the voice band of each channel, so that the repetitive zone used in the channel of the same frequency can be identified. . Since the same frequency channel is not assigned to different mobile stations within the repetitive zone, when the position of the mobile station is determined by the reception level, the reception levels of other mobile stations are not mistakenly used. There is an advantage that an accurate position detection can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a concept of a wireless zone configuration in a mobile radio system, FIG. 2 is a diagram for explaining processing of a conventional mobile station position detection system, and FIG. 3 is a mobile station position detection of one embodiment of the present invention. FIG. 4 is a diagram for explaining the processing of the method, FIG. 4 is a diagram showing an example of a distribution of frequency bands used in a radio channel, FIG. 5 is a diagram showing an example of a time chart of control signal transmission outside the voice band,
FIG. 6 is a distribution diagram of frequency bands used by channels according to another embodiment of the present invention. 1 ... Service area, 2A-2C ... Repeating zone, 3 ... Wireless zone, 4 ... Base station, 5 ... Control station,
6A, 6B ... Mobile station, 7, 9 ... Identification code transmission band, 8 ... Communication voice band, 10 ... Identification code, 11 ...
… Control signal, 12 …… Identification signal

Claims (1)

[Claims] 1. A service area is divided into a plurality of repetitive zones, and the repetitive zone is further divided into a plurality of wireless zones. Channels with different radio frequencies are placed in each wireless zone so that they do not interfere with each other, and the same channel is repeatedly used in the wireless zones that do not interfere with each other between different repeating zones. In a mobile radio system in which the reception level of a channel transmitted by a station is measured and the radio zone of the base station with the highest level is determined to be the radio zone in which the mobile station is located, the mobile station uses the channel in use to move outside the voice band. Repeatedly sends a unique identification code for each zone, and when determining the wireless zone where the mobile station is located, the channel at which the base station measured the reception level is used. If the identification code of the channel matches the identification code transmitted by the mobile station to be determined, it is validated. On the other hand, if it does not match, the received level measurement value of the channel is considered invalid. Mobile station position detection method characterized by.