JPH04150532A - Radio communication system - Google Patents

Abstract

PURPOSE:To shorten the selection time for a communication channel, and simultaneously, to prevent disturbing other systems in the course of communication by taking in the selecting function and the determining function of the communication channel for transmitting data of a base station in a mobile station. CONSTITUTION:Each base station 1-1 to 1-n checks the communication channel being not used by other base stations by executing carrier sense, and sends a communication permission signal to the mobile stations 2-1 to 2-n at a definite period by using this communication channel. Each mobile station 2-1 to 2-n receives the communication permission signal, and confirms and stores previously the information of the communicatable base station 1-1 to 1-n and communication channel and a receiving field level, etc. In the case of the execution of the communication, each mobile station 2-1 to 2-n reads out the communicatable base station 1-1 to 1-n and communication channel stored before, and it communicates with this base station 1-1 to 1-n by this communication channel. Thus, each base station 2-1 to 2-n determines quickly the communicatable base station 1-1 to 1-n, and it can start promptly the communication by using the communication channel not to disturb the communication of other mobile stations.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wireless communication system in a wireless communication system consisting of a plurality of base stations and a plurality of mobile stations.

(Prior art) The wireless communication system described above is used in inventory management systems such as warehouses, boss systems, etc. that transmit data in real time between computers installed at head offices, etc., and numerous OA @ terminals scattered around. There is.

FIG. 2 shows a conventional wireless communication system of this type, which adopts a multi-channel access method in which multiple wireless channels are shared by multiple mobile stations 5-1 to 5-m from the viewpoint of effective use of radio frequencies. , each of the mobile stations 5-1 to 5-m uses an available communication channel to transmit data with the base station from which the best wireless communication conditions can be obtained among the base stations 4-1 to 4-n. The determination of a communication channel to be used for data transmission and the selection of a base station are performed using a wireless control channel common to the system under the control of the communication control device 6.

Next, a specific example of a communication procedure for transmitting data from the mobile stations 5-1 to 5-ta to a predetermined partner in the above system will be explained.

(b) The mobile station uses the carrier sense function to check communication channels that are currently not in use.

(b) Next, the mobile station determines the communication channel on which it wishes to communicate, and transmits a connection request including the channel number to the base station using the control channel.

(c) Each base station that has made this connection request adds field strength information and the like to this connection request and transmits it to the communication control device 6.

(d) When the communication control device 6 receives the connection request from the base station, it selects one optimal base station based on the field strength information and transmits a connection permission signal. Note that communication is closed for all base stations other than the selected base station.

(e) The base station that has been granted connection permission uses the control channel to transmit a connection permission signal to the mobile station that has issued the connection request.

(f) The mobile station that receives this connection permission signal transmits data to the base station using the designated communication channel. Note that the data is sent to a predetermined party via the communication control device 6.

(Problem to be Solved by the Invention) However, in the communication procedure in the above wireless communication system, when determining a communication channel for communication between a base station and a mobile station, the mobile station and the base station first transmit necessary information through communication control. The communication controller then determines the optimal base station and notifies the corresponding base station and mobile station, which results in a long processing time (there was a problem that data transmission could not be started quickly). This problem has been difficult to solve simply by improving the processing speed of the hardware.

Additionally, when a mobile station checks for an empty communication channel, it may not be able to detect a communication channel used by another mobile station depending on the positional relationship of the zone configuration, and may mistakenly determine that it is an empty communication channel. There were three points regarding the possibility of interfering with the station's communications.

The present invention has been made to solve the above problems, and includes a function for selecting a base station and a function for determining a communication channel for data transmission in a mobile station, thereby shortening the time for selecting a communication channel. At the same time, it is an object of the present invention to provide an excellent wireless communication method that does not interfere with other systems in communication.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a wireless communication system in which communication is carried out by sharing a plurality of communication channels between a plurality of base stations and a plurality of mobile stations. The base station is equipped with a means for detecting a communication channel that is not used by another base station, and transmitting a connection permission signal to a mobile station at a constant cycle using the detected communication channel, and for each mobile station, receiving the connection permission signal from each base station within the communication range;
Each base station, its communication channel, and received electric field level are stored at the time of reception, and each mobile station transmits the stored communication corresponding to that base station to the base station most suitable as a communication partner at the time of communication. It uses channels to communicate.

(Operation) Each base station performs carrier sense to check for communication channels that are not used by other base stations, and uses the communication channels to transmit connection permission signals to mobile stations at regular intervals.

The base stations with which each mobile station can communicate may change depending on the location of the mobile station. Therefore, each mobile station receives the connection permission signal, confirms and stores information such as the base station with which it can communicate, the communication channel, and the received electric field level.

When communicating, each mobile station reads the already stored base station and communication channel with which it can communicate, and communicates with that base station using that communication channel.

As a result, each mobile station can quickly determine a base station with which it can communicate, and immediately start communication using a communication channel that does not interfere with the communication of other mobile stations.

(Embodiment) FIG. 1 is a configuration diagram showing an embodiment of the present invention, in which a plurality of base stations 1-1 to 1-n, a plurality of mobile stations 2-1 to 2-m2
The communication control device 3 covers one communication area, a so-called small zone.

Each base station 1-1 to 1-n is connected to a plurality of wireless devices that can configure a radio line (communication channel) with a plurality of mobile stations 2-1 to 2-m, and It is composed of a control device (none of which is shown) that performs data transmission between stations, data exchange between communication control devices 3, and other predetermined communication procedures.

Furthermore, the mobile stations 2-1 to 2-m are each base station 1-1 to 1-n.
A wireless device that can configure a wireless line using any channel, and a data terminal that has a data transmission function (none of which are shown).

Then, each mobile station 2-1 to 2-m uses an empty communication channel among the plurality of communication channels to transmit data to the optimal base station, and the data is sent to a predetermined base station via the communication control device 3. transmitted to the other party.

Next, the operation of this embodiment will be explained in detail for base stations and mobile stations based on FIGS. 1 and 3. In addition, the third
The figure is a flowchart showing the operations of the base station and mobile station.

First, the operation of each base station 1-1 to ln will be explained. When the base station is powered on, it automatically starts carrier sensing (100 in FIG. 3) and checks for unused communication channels around the base station (101 in FIG. 3).

Here, each base station is set so that it can reliably confirm the communication channels used by other base stations. Each base station then uses its vacant communication channel to transmit a connection permission signal including its own station ID number etc. for a certain period of time to each mobile station 2-1 to 2-m within the communication area. 102), waits for a response from each mobile station (103 in FIG. 3). In FIG. 1, base station l-1 uses a communication channel at radio frequency ft, and base station 1-2 uses radio frequency f2 A case is shown in which the base station 1-n transmits a connection permission signal to each of the mobile stations 2-1 to 2-m using the communication channel using the radio frequency f7. If each base station does not receive a response from the mobile station within a certain period of time, it retransmits the connection permission signal using the communication channel described above, and repeats this until a response is received (102, 103, 104 in Figure 3). . When each base station receives a response from one of the mobile stations, it immediately stops transmitting the connection permission signal (105 in Figure 3) and establishes a connection with the wireless line (the communication channel described above). 106)
, starts data transmission via the communication channel (third
Figure 107).

After the data transmission is completed, the base station disconnects the wireless line (FIG. 3 (108)), searches for an empty communication channel, transmits a connection permission signal, and prepares for the next communication.

Next, the operation of each mobile station 2-1 to 2-m will be explained. Each mobile station automatically starts carrier sensing when it is powered on (Fig. 3 200), and each base station 1-
A connection permission signal transmitted from 1 to 1-n is detected (201 in FIG. 3). Then, for each connection permission signal detected,
The base station ID number included therein, the electric field strength at the time the connection permission signal was received, and the communication channel are stored in the memory (202 in FIG. 3).
Each mobile station can immediately know all base stations within its communication range. For example, in Figure 1,
Assuming that the mobile station 2-1 is able to receive the connection permission signal transmitted from the base station 1-1゜1-2, it will receive the base station ID number, its communication channel (or radio frequency f+, b), electric field strength, etc. is stored in memory. When each mobile station transmits data to the base station (Fig. 3, 203), it first checks each electric field strength stored in memory, and determines the ID number and communication channel of the base station corresponding to the highest electric field strength. 204 and 205 in FIG. 3.
). If each base station cannot receive the connection permission signal after a certain period of time has elapsed, it selects the base station with the next highest electric field strength and waits for the connection permission signal transmitted on the corresponding communication channel. From now on, if reception is not possible, change the base station one by one in the same way (Fig. 3 205゜206.2
07). When each mobile station receives a connection permission signal from the corresponding base station, it transmits a response signal requesting data transmission to that base station using the communication channel (see Fig. 3.2).
08). As a result, the base station stops transmitting the connection request signal, and a wireless line connection is established between the mobile station and the base station via the communication channel (209 in Figure 3), and the connection between the mobile station and the base station is established. Data transmission is executed in (Fig. 3, 2).
10). When the data transmission is completed, the wireless line is released and can be used by other mobile stations.

(Effects of the Invention) As described above in detail, according to the present invention, a base station has a carrier sense means and a connection permission signal transmitting means, and a mobile station has a means for storing base stations capable of communicating with a plurality of base stations. When communicating with a mobile station or a base station, the optimum base station and communication channel to communicate with can be quickly selected, and communication can be started immediately.

Furthermore, since there is no transmission from mobile stations that cannot receive connection permission signals, there is no interference from other systems using the same communication channel.

Furthermore, since the base station has a carrier sense means, as traffic increases, adding base stations will not affect the system configuration, and the load on the communication control device will be extremely small (can be used from small to large scale). The system can also be easily expanded.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a conventional wireless communication system, and FIG. 3 is a flowchart showing operations of a base station and a mobile station. 1-1 to ln...Base station, 2-1 to 2-m...Mobile station, 3...Communication control device. Patent applicant: Oki Electric Industry Co., Ltd. Dairyoku Sotari configuration diagram Figure 1 Figure 3 Subordinate L'! ! :N, 9 Liangdong I Lu No. 2 5-1 Moving meeting 5-2 Ota power A giving system field 1 collection round i diagram

Claims (1)

[Claims] In a wireless communication system in which a plurality of base stations and a plurality of mobile stations communicate by sharing a plurality of communication channels, each of the base stations is provided with communication that is not used by other base stations. comprising means for detecting a channel and transmitting a connection permission signal to a mobile station at regular intervals using the detected communication channel, the connection permission signal being sent to each mobile station from each base station within a communication range; The mobile station receives the signal and stores information such as each base station and its communication channel at the time of reception, and each mobile station stores information corresponding to the stored base station at the time of communication. A wireless communication method characterized by communication using a communication channel.