JP2794860B2 - How to search for wireless channels - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mobile phone system, in which a user having a higher priority is given priority during high traffic by changing a search start time of an available wireless channel according to a user class. The present invention relates to a search method that enables a wireless line to be connected.

[Prior Art] There is a high demand for a mobile phone service that can move anywhere within a service area to make and receive calls. Japan Calling Telephone Corporation (MTT) has developed a small portable device using the wireless switching network of the car phone system to provide a wide area mobile phone service.

On the other hand, with the spread of cordless telephones, the cordless telephone system has been expanded, and a private mobile telephone system in a limited area can be realized as a system cordless telephone as shown in FIG. It uses frequencies in the 250/380 MHz band, has 89 channels including control channels, and has a service radius of 50 m for duplex using a small antenna power of 10 mW.
It is of the small zone type (micro zone type). As shown in FIG. 1, this system comprises, for example, a radio system controller 10, fixed radio stations A to N, and mobile phones a to n. Each element of this configuration will be briefly described.

* Mobile phone: has the function of accessing a fixed wireless station wirelessly and automatically performing location registration with the fixed wireless station or the wireless system controller. It has a function of registering a location with another fixed wireless station or a radio system controller as the mobile phone moves, and changing the location registration. The outgoing / incoming call operation can be performed from any place in the service area.

* Fixed radio station: An incoming call and a call can be made by converting a downlink signal from a radio system control device into a radio signal and transmitting it to a mobile phone. On the other hand, a transmission operation and a communication by transmission can be performed by receiving and demodulating an uplink wireless signal from a mobile phone and transmitting the signal to a wireless system control device by wire. Also, it sends out a notification signal necessary for location registration.

* Radio system controller: The radio system controller connects a fixed radio station that covers the radio wave zone where the mobile phone is located and the extension of the private branch exchange PABX, which has a one-to-one relationship with the mobile phone, when making and receiving calls. This is a device that forms a communication path. In some systems, the radio system controller itself has an exchange function.

In this way, a mobile phone system can be realized at hand. These systems have not yet been provided with a nationwide Internet service, but have been actively used in limited areas such as limited buildings. When a large number of people start using a mobile phone at the same time in a limited area, wireless traffic naturally increases, and a situation arises in which connection is difficult. The content of a call on a mobile phone varies from person to person, but can be broadly divided into those that require urgency and those that do not need to be immediate. There are emergency calls related to maintenance in the building and wired calls such as VIP persons, which can be classified as general calls.

Apart from general calls other than emergency or VIP calls, it is desirable for these calls to be able to be connected immediately when needed due to their importance. Conventionally, in order to respond to this type of request, a fixed wireless station forcibly disconnects a general call that has been connected when a receiver dedicated to the control channel detects a call request of VIP during a call with a general mobile phone, The method of setting the line in response to a VIP call request was taken. Although this method clearly satisfies the requirements of VIP, there is also a problem in use, such as dissatisfaction because the general public is forcibly disconnected.

[Object of the Invention] In order to solve these drawbacks, the present invention divides available radio channels into groups according to a service class of a mobile phone, and changes the start time of searching for an empty channel according to the service class. By urging users of low-volume mobile phones to abandon calls and minimizing the use of wireless channels to secure available channels and enable high-ranking users to preferentially connect to wireless lines during high traffic. The purpose is to do.

[Description of Configuration and Operation of the Invention] The configuration of the present invention includes a fixed radio station connected linearly or indirectly to a wired line,
In a mobile phone system including a plurality of mobile phones capable of wirelessly communicating with the fixed wireless station and each having a service class, a wireless channel used in the mobile phone system is divided into arbitrary plural groups, When the fixed radio station has made an access for calling to the fixed radio station, the fixed radio station identifies the service class of the mobile phone, and the available radio channel group can be used according to the service class of the mobile phone. When a wireless channel group is specified, and all the wireless channels of the specified wireless channel group are used, a search is performed including a wireless channel group corresponding to a service class of another mobile phone after a lapse of a predetermined time, This is a wireless channel search method characterized by setting a wireless line.

 Hereinafter, the present invention will be described in detail.

FIG. 2 shows the grouping of wireless channels by service class and the search time for each group. FIG. 3A and FIG. 3B show an example of the flow at this time.

 This will be described below with reference to the drawings.

In FIG. 3, the service classes are classified into urgent or high-priority classes by (c), the general classes are (b),
The middle is (b). Wireless channels are divided into C, D, and E groups in the general (a) class, for example. In this state, when a general portable telephone of class (a) attempts to make a call, the fixed wireless station first determines the service class of the caller. It is simple to make this determination using, for example, an individual telephone number assigned to the mobile phone. Next, the fixed wireless station tries to find an empty channel from the wireless group of C according to the service class. But,
When all the radio channels of the group C have been used, there is no radio channel to be assigned, so a first special warning sound or voice announcement is made to the mobile phone. The mobile phone listens to this warning sound or voice announcement, and determines here whether to temporarily give up or wait a little longer. When receiving this signal, the mobile phone and the fixed wireless station mutually cut off the radio wave of the control channel,
The control channel occupation time may be short.

When the caller of the mobile phone hears the warning sound or the voice announcement unless otherwise urgent, the caller gives up the temporary connection and turns off the mobile phone.

If you want to make a quick call even after hearing the warning sound or voice announcement, wait for about one minute, for example, and the fixed wireless station searches for a free channel in the next wireless group D and re-connects with the mobile phone and the control channel. Is set, and if a vacant channel is found, this is communicated to the mobile phone. The mobile phone receives this signal and dials it to set up a line and make a call.
Since the wireless group of D is more likely to be free than the wireless group of C, the connection probability increases.

However, if the wireless group D is also closed, the fixed wireless station issues a second warning sound or an announcement to notify the mobile phone user. Similarly, the user of the mobile phone hears this warning sound or audio announcement,
At this point, it is determined whether to give up the call temporarily or wait a little longer. Unless you are in a hurry, the caller of your mobile phone will hang up when you hear this beep or voice announcement
Press the button to give up the temporary connection. As a result, the wireless channel group E is kept unused and unused. If the user wants to make a quick call even after hearing the warning sound or voice announcement, the fixed wireless station searches for an available channel of the next wireless group E after waiting for a certain period of time, for example, about one minute. If a vacant channel is found, a line is set up and a call can be made. Since the radio group E is more likely to be free than the radio group D, the connection probability is further increased.

However, if the wireless group is also closed, the fixed wireless station makes a third warning sound or voice announcement and notifies the mobile phone user. Any further processing is impossible because all wireless channels are blocked.

In the case of the service class (b), the state is slightly different from that of the general (a), and the wireless channel B, which is a combination of C and D, which is generally used, is searched from the beginning. Therefore, since a general person searches for a wider wireless channel than when trying to make a call first, the probability of finding a free channel from the beginning is high.

In the case of the service class (c), the situation is largely different from that of the general (a), and from the beginning, all wireless channels A including C, D, and E generally referred to are searched. Therefore, the probability of finding a vacant channel from the beginning is higher because the general public is searching for a wider radio channel than when trying to make a call.

FIG. 4A and FIG. 4B show other control examples of these controls. The difference from FIG. 3 is that, for example, after a call is made by a person of the service class (a) and the radio channel group C is occupied and the first warning sound or voice announcement is sent out, the fixed radio station transmits During a timer period until a vacant channel of the radio group D is searched, the vacant radio channel group is checked again for vacancies, and if there is vacancy, the line is connected. As a result, if a wireless D group is available, connection can be made earlier without waiting for a timer, and since the next wireless D group need not be used, the probability of leaving the D group is increased, and the use of equipment of another service class is increased. Can be connected more preferentially.

[Explanation of effects] As described in the above description, mobile phones are divided into groups and used, so there is a group in the wireless channel group for VIPs or emergency personnel that takes a long time to connect. And a wireless channel group with a high probability of “vacancy” can be secured. On the other hand, for VIPs or emergency persons, all channels are freely searched, so that line setting can be performed from among the wireless channel groups having a high probability of "vacancy".

For this reason, VIPs or emergency personnel were able to increase the line supplement rate compared to the general public. Another advantage is that even if it is an ordinary person, if it waits for time, it has the same connection probability as a VIP or emergency person. This kind of dissatisfaction has been completely resolved, as no longer is forced to disconnect the line during a call.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of a mobile phone system in a limited area configured as a "system cordless phone". FIG. 2 is a diagram showing the allocation and opening of wireless channels according to the (service) class of the user of the mobile phone. Diagram showing waiting time until channel search, FIGS. 3A and 3B show (service) of user of mobile phone
FIG. 4A is a diagram showing a search flow of an empty channel according to a class, and FIGS. 4A and 4B are diagrams showing a search flow according to another embodiment in which a part of FIG. 3 is modified. A to N: fixed radio stations, an: mobile phone 10: radio system controller, 20: private branch exchange,

Claims (1)

(57) [Claims] 1. A portable telephone system comprising a fixed wireless station connected linearly or indirectly to a wired line and a plurality of mobile phones capable of communicating with the fixed wireless station wirelessly and each having a service class. The wireless channels used in the telephone system are divided into arbitrary groups, and when the mobile phone accesses the fixed wireless station for calling, the fixed wireless station changes the service class of the mobile phone. Identifying a usable radio channel group corresponding to the service class of the mobile phone among the radio channel groups, and when all the radio channels of the specified radio channel group have been used, After the elapse, search including the wireless channel group corresponding to the service class of other mobile phones, and set up the wireless line. A wireless channel search method characterized by specifying