JPH02244831A - Radio communication system - Google Patents

Abstract

PURPOSE:To enhance communication efficiency by proving a re-call control means which performs a connecting operation with a radio base station not being set at a congested state out of another radio base stations capable of performing radio communication in the case of receiving congestion information from the radio base station with each terminal station at the time of performing the connecting operation. CONSTITUTION:The re-call control means 27 is provided on each terminal station C, and the connecting operation is interrupted in the case of receiving the congestion information from the radio base station B by the re-call control means 27 at the time performing the connecting operation, and also, the radio base station B not being set at the congested state out of another radio base stations B capable of performing the radio communication is found out, then, the connecting operation is performed with the radio base station B. Therefore, a call operation can be performed without awaiting until the congestion is dissolved even when the congested state occurs in the radio base station B. Thereby, the communication efficiency can be enhanced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides data transmission between a central control station and a plurality of terminal stations via a wireless base station, such as a teleterminal system. The present invention relates to a wireless communication method applied to a wireless communication system that performs transmission, etc.

(Prior Art) In recent years, various wireless communication systems have been developed with the development of communication technology and the diversification of communication needs, one of which is a teleterminal system.

This type of system includes, for example, a central control station A having a host computer, and a central control station A as shown in FIG.
A plurality of wireless base stations 81 to 81 to Bm are respectively connected to each other via line lines, and a plurality of terminal stations 01 to 01 to 81 to Bm are connected to each other via wire lines, and a plurality of terminal stations 01 to 81 to Bm are connected to each other via wire lines, and a plurality of terminal stations 01 to 81 to Bm include, for example, a mobile station mounted on a vehicle or a fixed station installed in a store.
It is composed of Cn. Of these, each wireless base station B1-B
m constitutes a wireless zone as shown by the broken line in the figure, for example, according to the small wireless zone method. Each of the terminal stations 01 to Cn is connected via a wireless line to the wireless base station of the wireless zone in which it is located among these wireless zones, and is further connected to the central control station A via this wireless base station. data is transmitted between the central control station A and the central control station A.

By the way, in this type of system, for example, when communications are concentrated on one radio base station, this radio base station may fall into a state of congestion. For this reason, in the past, wireless base stations 81 to B
M is provided with a congestion notification means, and when a congestion state occurs, the radio base stations 2a to 2m send control information containing information indicating that the congestion state has occurred to each terminal station C1 to Cn, and thereby initiate a call. The desired terminal station is set to a call standby state.

(Problem to be solved by the invention) However, in such a conventional system, wireless base stations B1 to
Since the terminal stations 01 to Cn are forced to wait until the congestion state of Bm is resolved, there is a problem in that the call waiting time of the terminal stations C1 to Cn becomes extremely long depending on the degree of congestion.

Therefore, the present invention focuses on the above points, and even if a wireless base station becomes congested, it is possible to perform a call operation without waiting until the congestion is resolved, thereby improving communication efficiency. Its purpose is to provide a communication method.

Another object of the present invention is to provide a wireless communication system that increases the probability of selecting a wireless base station with a high reception field strength and thereby allows data transmission with good transmission quality.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a central control station and a plurality of wireless stations connected to the central control station via communication lines and each forming a predetermined wireless zone. It consists of a base station and a plurality of terminal stations that are selectively connected to these wireless base stations via wireless lines within their wireless zones, and the appropriate communication between these terminal stations and the central control station is In a wireless communication system that performs communication via a wireless base station, each terminal station is provided with a re-calling control means, and when a congestion notification is received from the wireless base station during a connection operation, the re-calling control means In addition to canceling the connection operation, the system searches for a wireless base station that is not in a congested state among other wireless base stations that can communicate wirelessly, and performs a connection operation with this wireless base station. be.

Another aspect of the present invention is a non-congestion system that does not fall into a congestion state. il
When searching for a base station, the received field strength of a control channel sent from a wireless base station is monitored, and wireless base stations that are not in a congested state are searched in descending order of received field strength.

(Function) As a result, according to the present invention, if a congestion @ notification is sent from a wireless base station during a connection operation, it is possible to determine whether or not another wireless base station capable of wireless communication is in a congestion state. This is determined, and a connection operation for making a call is performed with a wireless base station that is not in a congested state. Therefore, it is possible to automatically and immediately select another radio base station to which a call request can be made and perform a call connection operation without waiting until the congestion of the radio base station is resolved. Therefore, the call waiting time of the terminal station is shortened, thereby improving communication efficiency.

According to another aspect of the present invention, since the presence or absence of congestion is determined in order from the radio base station with the highest received field strength, the probability of selecting a radio base station with good radio communication quality is increased, and thereby the transmission It becomes possible to perform data transmission with fewer errors.

(Embodiment) Next, a wireless communication system in an embodiment of the present invention will be described. FIG. 1 is a functional block diagram showing the configuration of a wireless communication system to which a wireless communication method according to an embodiment of the present invention is applied. For convenience of explanation, only the terminal station C4 and the radio base stations B1 and B4 are shown among the terminal stations C1 to Cn and the radio base stations 81 to Bm shown in FIG. 5, for convenience of explanation.

First, the wireless base stations B1 and B4 include a transmitting/receiving device 13 including a transmitting/receiving section 11 for a control channel and a transmitting/receiving section 12 for a communication channel, an antenna duplexer 15, and an antenna 16.
These devices connect terminal stations C1 to Cn.
It is now possible to send and receive signals between the two via wireless lines.

The radio base stations Bl and B4 also include a control unit 14, which controls the transfer of signals to the central control station A, and also controls the transmission of signals to the central control station A, and also controls the transmission of signals to the terminal stations 01 to Cn. It performs signal transmission and reception control, N-wall monitoring, IW@ notification control, etc. with terminal stations existing in the B1 and B4 wireless zones.

On the other hand, the terminal station C4 has a transmitter (TX) 21 and a receiver (
RX) 22 and a synthesizer section 23 that specifies transmission and reception channels for these transmitting section 21 and receiving section 22, and these circuits transmit signals to the radio line via the antenna duplexer 24 and the antenna 25. It sends and receives data.

Furthermore, the terminal station C4 of this embodiment has a control section 26 whose main control circuit is, for example, a microcomputer. This control unit 26 controls the transmission and reception of signals over the wireless line,
In addition to means for controlling the transfer of signals to the data terminal 28, a re-calling control means 27 is provided. This re-calling control means 27 operates when the wheel axle information is inserted into the control information received from the radio base station during the connection operation, and performs the following control operation. That is, when the arrival of wheel set information is detected, first, the connection operation with the wireless base station is stopped, and the received electric field strength of each control channel coming from another adjacent wireless base station is detected.

Then, the wireless base stations are selected in descending order of received field strength and their control information is received, and when a wireless base station is found that does not have congestion information inserted in the received information, a predetermined communication is established between the wireless base station and this wireless base station. Performs call connection operations.

Next, the wireless communication system of this embodiment will be explained based on the above configuration. Assuming that the terminal station C4 is located within the wireless zone of the wireless base station B1 as shown in FIG. 3, the terminal station C4 receives the control channel from the wireless base station B1 as shown in FIG. Control information is constantly being sent via the communication channel, and in parallel, polling information is being sent via the communication channel.

In this state, when the terminal station C4 sends data to the central control station, it first checks the operating state of the wireless base station B1 based on the control information. As a result of this confirmation, if it is confirmed that the radio base station B1 is now operating normally, the terminal station c4 sends a call request to the radio base station B1 according to the polling information. Radio base station B1 then accepts this call request, sets up a wireless communication channel with terminal station C4, and transfers the call request to central control station A. When this call request is transferred, the central control station A sets up a communication line with the terminal station c4 that is the calling source, and thereafter enters a data receiving state. However, terminal station C4
sends the output data from the data terminal 28,
This data is the communication channel of the wireless line, wireless base station B1
and are transmitted to the central control station A via the line and received by the central control station A.

On the other hand, suppose now that the wireless base station B1 is in a wheel set state, and accordingly, wheel set information is inserted into the control information sent from the wireless base station B1 as shown in FIG. Then, when the terminal station c4 detects the congestion information from the control information at the start of the connection operation, it first detects the congestion information from the wireless base station B.
The connection operation by 1 is canceled. Next, as shown in FIG. 3, control channel signals from other surrounding wireless zones are received, and the control channel with the highest received field strength is selected from among them. For example, if the reception level of the control channel from radio base station B4 is now the highest, this control channel is selected. Then, the control information arriving via the control channel of this radio base station B4 is transmitted to the third
The information is received as shown in the figure, and the operating status of the wireless base station B4 is confirmed from the contents.

Assuming that the operating state of this wireless base station B4 is normal and the width w1f'r1 information is not inserted in the control information, the terminal station C4 selects the wireless base station B4 and communicates via that communication channel. A call request is sent to the wireless base station B4 in accordance with the polling information sent. Then, the radio base station B1 accepts the call request and sets up a wireless communication channel with the terminal station C4, as in the case of the radio base station B1, and also sends the call request to the central control station A. Forward. When this call request is transferred, the central control station A sets up a communication line with the terminal station C4, which is the calling source, and thereafter enters a data receiving state.

On the other hand, if the radio base station B4 is in a wheel set state, and therefore, the set wheel information is also inserted into the control information sent from the radio base station B4, the terminal station C4 detects the received field strength Based on the results, the wireless base station B2 with the second highest received field strength of the control channel is selected.

And, as shown in Figure 4, this nothingness! jjl When control information sent from base station B2 is received, and wheel set information is not inserted in this control information, a call is made to wireless base station B2 according to polling information sent from this wireless base station B2 via a communication channel. Send a call request.

In this case, the terminal station C4 becomes capable of data communication with the central control station A via the wireless base station B2.

If the radio base station B2 is also in a wheel-wheel state, the radio base station with the third largest received field strength of the control channel is selected, and the occurrence of congestion is determined based on the control information sent from this radio base station. The presence or absence of is determined. If this wireless base station is normal, each of the wireless base stations B4. B2
Similarly to the case described above, a call request is sent from the terminal station C4 to the radio base station, whereby the terminal station C4 is connected to the central control station A and data communication becomes possible. However, the wireless base station B4. If the control channel cannot be received at all from a wireless base station other than B2, or even if the control channel can be received but the received field strength is below the specified level, the terminal station C4 enters the call standby state and periodically The control operation for calling as described above is repeated.

As described above, in this embodiment, the re-calling control means 27 is provided in the terminal stations 01 to Cn, and when the wheel axle notification is inserted in the control information sent from the wireless base station B1 at the time of connection operation, - the above-mentioned The re-calling control means 27 cancels the connection operation, receives the control channels of each surrounding wireless zone, detects the received electric field strength of each, selects the wireless base stations from among them in order of the received electric field strength. Since wireless base stations that are not in a congested state are detected and call connection control is performed, even if wireless base station B1 is in a wheel-centered state during connection operation, the congestion of wireless base station B1 is prevented. Without waiting until the cancellation is resolved, a call connection is made to another wireless base station capable of wireless communication, thereby making it possible to perform data communication with the central control station A. Therefore, the call waiting time of the terminal station is shortened, thereby improving communication efficiency. Furthermore, in this embodiment, when searching for another wireless base station that is not in the wide range state,
The received field strength of the control channel of each wireless base station is detected, and the presence or absence of the 1iil state is determined in order from the wireless base station with the highest received field strength.
The probability of selecting a radio base station with good radio quality is increased, and thereby data transmission with fewer transmission errors can be performed. In addition, in this embodiment, connection control is not performed for wireless base stations whose received field strength of the control channel is below a specified level, so there are many transmission errors in data communication after connection, and data transmission is actually not performed. There is no need to worry about problems such as the inability to do so.

It should be noted that the present invention is not limited to the above-mentioned tablets. For example, in the above embodiment, when the wireless base station B1 is in a congestion state, another wireless base station B4. B2 is sequentially selected to determine whether or not it is in the wheel axle state, but as a result of this determination of the wheel axle state, all wireless base stations B4. If it is determined that B2 is in the axle state, after the determination is completed and before transitioning to the call standby state, the J two-legged wireless base station B1
The convergence state may be determined again. In this way, if the congestion of the wireless base station B is resolved during the determination of the congestion state of the wireless base station B4゜B2, it is possible to make a call and connect to this wireless base station B1. can. In addition, the configuration of the wireless zone by each wireless base station, the communication procedure and signal system between the terminal station and the wireless base station, the configuration and control procedure of the re-calling control means, the control contents, etc. also deviate from the gist of the present invention. It can be implemented with various modifications within the scope.

[Effects of the Invention] As detailed above, according to the present invention, each terminal station is provided with a tU call control means, and when a tU call control means is received from the radio base station during a connection operation, the above-mentioned re-call is performed. The control means cancels the connection operation, and searches for a wireless base station that is not in a wheel spindle state among other wireless base stations capable of wireless communication dI, and performs a connection operation with this wireless base station. By doing so, even if a wireless base station becomes in a spindle state, it is possible to perform a call operation without waiting until the spindle is removed, thereby providing a wireless communication system that can greatly improve communication efficiency. be able to.

According to another aspect of the present invention, when searching for a wireless base station that is not in a congested state, the received electric field strength of the control channel sent from the wireless base station is monitored, and the received electric field strength is determined in descending order of the received electric field strength. There is nothing! By searching for 91 base stations, it is possible to increase the probability of selecting a wireless base station with a high reception field strength, thereby providing a wireless communication system that can perform data transmission with good transmission quality.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing the main parts of a wireless communication system to which a wireless communication method according to an embodiment of the present invention is applied, and FIGS. FIG. 5, which is a diagram showing a signal transmission procedure, is a schematic diagram showing an example of the configuration of a teleterminal system. A...Central control station, 81-Bm...Radio base station, C
1 to Cn...terminal station, 11...transmission/reception unit for control channel, 12...transmission/reception unit for communication channel, 13.
...Transmission/reception device, 14...Control unit of wireless base station, 15
24... Antenna duplexer, 16. 25... Antenna, 21... Transmission section, 22... Receiving section, 23... Synthesizerizer section, 26... Terminal station control section, 27 ...
Recall control means, 28...data terminal. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) A central control station, a plurality of wireless base stations each connected to the central control station via communication lines and each forming a predetermined wireless zone, and a wireless base station for these wireless base stations within the wireless zone. In a wireless communication system consisting of a plurality of terminal stations that are selectively connected via a line, and in which communication is performed between these terminal stations and the central control station via an appropriate wireless base station, each of the above-mentioned When a terminal station receives a congestion notification from a wireless base station during a connection operation, it cancels the connection operation and searches for a wireless base station that is not in a congested state among other wireless base stations with which wireless communication is possible. A wireless communication system characterized by comprising re-calling control means for performing a connection operation with a wireless base station. (2) Claim characterized in that the re-calling control means monitors the received electric field strength of the control channel sent from the wireless base station, and searches for wireless base stations that are not in a congested state in the order of the received electric field strength. (1) Wireless communication method described.