JPS62101135A - Composite radio zone mobile communication system - Google Patents

Abstract

PURPOSE:To simplify and economize a controller by providing plural large/small radio zones superposedly in a service area, installing a base station to each zone and using a difference base station to be accessed in response to the moving speed of a mobile station. CONSTITUTION:Plural kinds of radio base stations are provided, the 1st radio base station 2 constitutes a radio zone and the 2nd radio radio base station 3 constitutes a small radio zone. When the mobile station 1 communicates with the base station 2 or 3 and the mobile station is an on-vehicle station on an automobile or a train, since the mobile speed is large, the mobile station 1 makes communication with the base station 2. When the mobile station 1 is carried at speed such as walking speed as a portable ratio equipment or used while being stopped, since the moving speed is small, the mobile station 1 makes communication with the base station 3. Thus, the probability of channel changeover during communication is small, the processing quality of the controller is decreased and the control method is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mobile communication system that aims to reduce the amount of control processing and utilize frequencies effectively.

(Conventional technology) In mobile communication systems, in order to increase subscriber capacity and expand the service area, the service area is divided into several wireless zones, and a base station is installed to cover each wireless zone. A cell system is adopted in which the same frequency is repeatedly used between base stations where interference does not occur. In order to further increase subscriber capacity and make more effective use of frequencies, it is necessary to make the wireless zone smaller. As the size of the wireless zone is made smaller, the distance over which the same frequency can be used repeatedly becomes shorter, as shown in FIG. 5, and when the wireless zone radius ar<aR, the repetition distance r<R. This increases the number of times the same frequency can be used repeatedly within a service area, thereby increasing subscriber capacity and making effective use of frequencies.

(Problems to be Solved by the Invention) In mobile communication systems, processes such as mobile station location registration and channel switching during communication are required in order to improve the efficiency of calls and ensure continuity of calls. As the wireless zone becomes smaller, the probability of passing through the wireless zone boundary during communication increases as the mobile station moves, and it becomes necessary to switch channels to continue communication. This probability largely depends on the moving speed of the mobile station, and as shown in Figure 6, if the moving speed is small,
The probability decreases even if the wireless zone is small, but if the moving speed of a mobile station such as a car phone is high, the probability becomes extremely large as the wireless zone becomes smaller. This channel switching requires complex control, and as shown in Figure 7, as the probability of channel switching increases, the amount of processing increases, many processing devices are required, and signals between processing devices are The speed also increases and the economy suffers. On the other hand, when the processing capacity is the same, there is a drawback that the subscriber accommodating capacity becomes smaller.

The purpose of the present invention is to overcome these drawbacks.

The purpose of this invention is to provide a plurality of sizes of radio zones and provide them in an overlapping manner, thereby simplifying the control device and making it more economical, as well as making effective use of frequencies.

(Means for Solving the Problems) As shown in FIG. 1, the present invention provides overlapping radio zones of different sizes within a certain service area, and installs a intelligence station in each zone. The most important feature is to access different base stations depending on the speed of movement.

Conventionally, the wireless zone configuration was the same regardless of the mobile station's moving speed, which complicated channel switching processing control during communication, and there was a limit to reducing the radius of the wireless zone, as well as limiting subscriber capacity. will be done.

(Function) When the speed of the mobile station is slow, it connects to a base station that makes up a small wireless zone, and when the speed of the mobile station is fast, it connects to a base station that makes up a large wireless zone. Therefore, regardless of the speed of the mobile station, the number of times base station switching can be reduced and frequencies can be used effectively.

(Example) FIG. 2 is a diagram explaining the first example of the present invention,
1 is a mobile station, 2 is a base station that covers a large wireless zone 2', and 3 is a base station that covers a small wireless zone 3°. In this figure, mobile station 1 is connected to base station 2 or 3.
Consider the case of communicating with In this case, when the mobile station is mounted on a car, train, etc., its moving speed increases, so mobile station 1 communicates with base station 2. The mobile station 1 communicates with the base station 3 when the mobile station 1 is moving at a walking speed or when it is used while stationary because its moving speed is low.

With this configuration, since the mobile station 1 with a high moving speed is in a large wireless zone, the probability of crossing the wireless zone boundary becomes small, and the mobile station 1 with a low moving speed
is a small wireless zone, but its movement is slow, so the probability of crossing the wireless zone boundary is also small. This reduces the possibility of channel switching during communication, reduces the processing amount of the control device, and simplifies the control method. In addition, this makes it possible to configure a very small wireless zone without increasing the load on the control device, increasing the number of frequency repetitions, making it possible to use frequencies effectively, and increasing subscriber capacity. is possible.

In this case, when the mobile station 1 accesses the base station 2 or 3, it is necessary to make its transmission power variable.

FIG. 3 is a diagram illustrating a second embodiment of the present invention,
1 is a mobile station, 2 is a base station that covers a large wireless zone 2゛, 3 is a base station that covers a small wireless zone 3゛,
4 is a transmission line connecting base stations 2 and 3; Among these, the base station 3 is a reception-only station that has only a receiver. In this configuration, the mobile station 1 with a high moving speed is connected to the base station 2.
Mobile station 1, which moves at a low speed, communicates with base station 3 on the uplink from the mobile station to the base station, and with base station 2 on the downlink from the base station to the mobile station. As a result, as in the first embodiment, the subscriber capacity can be increased without increasing the processing amount of the control device or the capacity of control signals. Furthermore, this embodiment has the advantage that the number of transmitters, which are relatively expensive compared to receivers, can be reduced and the system can be realized economically.

As a method for detecting the speed of a mobile device, for example, a) the mobile device detects the fading speed included in the received wave of the broadcast control channel (the incoming call control channel for current car telephones), and Including the detected speed information in the response signal; (a) Sending the speedometer information of the mobile to the mobile device and including that information in the calling signal, etc.; (d) Including the wave of the control channel such as the calling signal. A conceivable method is that the base station that receives the signal detects it based on the fading speed, transmits the information to the control station, and the control station selects the optimal base station.

(Effects of the Invention) As explained above, the present invention can realize a very small wireless zone without increasing the load on the control device, effectively utilize frequencies, increase subscriber capacity, and improve system It has the advantage that it can be realized economically.

[Brief explanation of drawings]

Figure 1 is a wireless zone configuration diagram which is the basis of the present invention, Figure 2 is a diagram showing the first embodiment of the invention, Figure 3 is a diagram showing the second embodiment of the invention, and Figure 4. Figure 5 is a conceptual diagram showing the frequency repetition usage, Figure 6 is a conceptual diagram showing the relationship between mobile station speed and the number of channel switching times, and Figure 7 is the number of channel switching times and control device processing. FIG. 2 is a conceptual diagram showing the relationship between quantities. 1...Mobile station, 2...Base station constituting a large wireless zone, 2...
・Large wireless zone, 3...Base stations forming the small wireless zone, 3'...
・Small wireless zone, 4...Transmission path between base stations.

Claims (2)

[Claims] (1) In a mobile communication system that communicates with mobile stations within a service area consisting of a radio base station arranged in each radio zone and a set of the radio zones, a plurality of types of radio base stations are provided, The first wireless base station constitutes a large wireless zone, the second known wireless station constitutes a small wireless zone, and the same area of the service area is configured with the two types of wireless zones mutually overlapping, and When the speed of the mobile station is faster than a predetermined value, it communicates with the first wireless base station, and when the speed of the mobile station is slow, it communicates with the second wireless base station. A composite wireless zone mobile communication system. (2) The first radio base station and the second radio base station are connected via a fixed transmission path, the second radio base station is a reception-only station, and if the speed of the mobile station is faster than a predetermined value, When a mobile station is connected to the first wireless base station, and the speed of the mobile station is slow, the uplink from the mobile station to the wireless base station is connected to the second wireless base station, and from the wireless base station 2. The composite radio zone mobile communication system according to claim 1, wherein a downlink to a mobile station is connected to said first radio base station.