JPH03108916A - Mobile communication control system - Google Patents

Abstract

PURPOSE:To evade a state of disabled control channel when one control channel goes to out of order by switching the control channel used specifically or due to notice into a prescribed control channel. CONSTITUTION:When a deciding means 3 decides it that consecutive use of a control channel CH in use is not possible based on its reception state, a notice means 4 informs it to an opposite station. A control channel switching means 5 selects a prescribed control channel in a station making the decision based on the decision. Moreover, the opposite station receiving the notice uses a channel switching means 5 to select a prescribed control channel CH. From the standpoint of communication between a base station 1 and a mobile station 2, the new control channel CH selected by the control channel switching means 5 in each station has the same frequency. Thus, the state of the control channel not in use is evaded and the normal communication state is always maintained.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a mobile communication IJt adopted by automatic IJ telephone customers.
[l system, specifically, it consists of a base station and a mobile station under the base station, and the base station and mobile station are:
The mobile communication (Ffmll fit system) is equipped with multiple bi-directional control channels for setting up communication channels.

[Conventional technology]

In mobile communication systems, a wireless zone is set up around one base station in which it can effectively communicate with mobile stations, and this base station and mobile stations within the wireless zone communicate by specifying a channel. Multi-channel access methods are common. In such a system, a control channel is often provided in addition to a communication channel in order to select a large number of communication channels.

On the other hand, in mobile communication systems that provide services over a wide area, a small zone system is adopted in which wireless zones are subdivided from the standpoint of efficient use of radio frequencies, and the same radio frequency is repeatedly used regionally.

As control methods using 'IIIgO channels, there are an individual zone vJ u method, which uses a different control channel for each wireless zone, and a multi-station control method, which uses a common υ+m channel in multiple wireless zones.

Focusing on the Bie station, the state of mobile io8 has two states: receiving and communicating, and the state transition from receiving to communicating is i+1l111 of either call origination or incoming call.
It is done through a process. In contrast to the random access format υ[1 that is nvhed from the mobile station side,
The latter is a simultaneous paging format initiated from the base station side.
+ Go. These control processes are divided into a process leading to communication channel allocation and a process leading to communication connection after confirming that separate allocation has been performed. The former is performed through a common control channel (incoming control and outgoing control channel) provided exclusively, whereas the latter is performed through a communication channel assigned to each mobile station.
As the number of subscribers increases, a plurality of common υJ@ channels are required.

Here, the control channel in the paging format initiated from the base station side is defined as P-CI~(, and the ft131m channel in random access format initiated from the mobile station side is defined as A-CI~).
It is written as 4.

The base station transmits to the mobile device via P-OH the usable A-CH*ff1 (frequency information) and an empty line signal (information on idle timing) to avoid signal collision when making a call. It is sent as a notification signal. The mobile station receives a broadcast signal from the base station when there is no communication, and obtains information on the channel (frequency) for making a call and the idle timing when making a call. In addition, mobile vJ8 has multiple channels set in advance as P-CH, and P-CH is set in advance in a predetermined order.
-C to select a channel higher than the specified level, and when there is no communication, the selected P-CH is always in the portable state.

On the other hand, the integrated service digital network (ISD), which integrates electronics networks, data networks, and image networks, provides complex services.
N), two types of channels are prepared: B-CH (communication channel) and D-CH (control channel). These channels are used for connection subsections and information transmission. Considering the case of a packet switching service, which is an example of a usage type, there are a B channel packet using a B channel and a D channel packet using an O channel. In recent years, there has been a growing trend to provide this I5DN service in mobile communication networks, but when implementing D-CH packets in mobile communication, the A-CH upstream (upstream: mobile A possible method is the 7J method, which uses (from the station to the base station).

[Problem to be Solved by the Invention] As mentioned above, communication lines are controlled by υI using a common control channel.
II), the 51fJ frequency is assigned so that the common vstill channel does not interfere with the communication channel, but in reality there is beneficial interference and interference to the common vstill channel. ,
I couldn't deal with it. For example, if the downlink (downlink: from base station to mobile station) control channel becomes abnormal, the receiving mobile station will not be able to recognize the abnormality in the channel, and if the uplink control channel becomes abnormal, the receiving Although the base station on the other side recognizes the abnormality in the channel, it simply does not take any action against the abnormality.

Therefore, if the control channel becomes abnormal due to interference waves or the like, the abnormal channel state will be maintained.

In addition, when the A-CH traffic temporarily increases as described above and the processing Ill exceeds the specified value, or when the A-CH traffic
When a packet signal with a good signal length is sent by H,
Other mobile stations will be unable to use the A-CH for a long time.

As mentioned above, the conventional mobile communication 1IJtll system can
The state of the channel was maintained and no measures were taken to avoid it.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a mobile communication control system that can avoid a situation in which a control channel of either a base station or a mobile station becomes unsuitable for use.

[Means for Solving the Problems] As shown in FIG. 1, the present invention consists of a base station 1 and a mobile station 2 under the base station 1.
2. Multiple bidirectional υ to set up a communication channel
) I11 channel C) Iyi is based on a mobile communication υ1111 system equipped with l, and the mobile communication 1131m
In the system, the technical means for solving the above problem is that the base station 1 and the mobile station 2 determine whether or not the control channel Cl-1 in use can be continuously used based on the reception state. and notification means 4 for notifying the partner station when the determination means 3 determines that continued use is not possible; A control channel switching means 5 is provided for switching the control channel CH to be used to a predetermined Ill tit channel Ct-t based on the determination or notification when there is a notification from the means 4.

The criterion for determining whether or not the control channel CH can be continuously used in the determination means 3 is the reception level of the interference wave, reception! jfl
It is determined based on the condition to be avoided determined within the system, such as the number of errors in the ll signal and traffic. Further, the ill level is determined based on the level of power required of the system.

The fulvolism of channel switching in the 11111 channel switching means 5 is determined in advance to be suitable for the system. In particular, in a system in which a situation unsuitable for continuous use may occur at the same time in a plurality of f, IJW channels C1 with a relatively high probability, from the viewpoint of preventing unnecessary channel switching, the vltE channel switching means 5:
It is preferable that the switching to the control channel CH is performed after confirming that the control channel to be switched is usable.

[For n]

In one station (base station 1 or mobile station 2), the determining means 3 determines which control channel C(-1
If it is determined that continued use is not possible, the notification means 4 notifies the partner station to that effect. Then, in the station that has made the determination, the control channel switching means 5 switches to the predetermined control channel C)-1 due to the determination. Also,
In the partner station that receives the above notification, the channel switching means 5 switches to a predetermined false channel CH due to the notification.

From the standpoint of communication between the base station 1 and the mobile station 2, the new control channel CH to be switched by the control channel switching means 5 at each station has the same frequency.

(Example〕 Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a block diagram showing an example of the basic configuration of a base station.

An incoming vl charge transmitting/receiving head 11, an outgoing $1til transmitting/receiving device 12, and a plurality of communication transmitting/receiving devices 13(1) to 13(
i) are connected in parallel to a central processing unit (CPtJ) 10 via a data line 14 and an input/output device 15.

The incoming vl rabbit transmitting/receiving device 11 is the above-mentioned P-CI-1.
Accordingly, the transmission/reception device 12 for control is
H is used to perform control communication with the mobile station. In addition, each communication transmitter/receiver fiH13(1) to 13(
+) communicates with the mobile station using a pre-assigned frequency.

FIG. 3 is a block diagram showing an example of the basic configuration of a mobile station.

This mobile station uses a control frequency in the receiving section 22 . The transmitter 23 is configured to perform various communications with the base station described above via the antenna 21.

Communication control when an error occurs in the control signal between the base 81 and the 8vJ inlet 2 will be explained with reference to the flowcharts shown in FIGS. 4 and 5.

This control signal error may occur due to interference from malicious interference and interference from other channels, or when the base station 1.
The failure of the mobile station 2 (this may be due to a failure of the i-device, etc.).

In the case of downlink tIl1111 channel abnormality, Figure 4 shows downlink i.
ll@0-chart showing communication control in case of channel abnormality.

On the mobile device 182 side, the CPU 20 constantly monitors the P-CH interrogation signal received by the receiver 22 via the antenna 21, and the l! Since the child signal of the III signal has a specific pattern, the number of errors of the 11111 signal is measured from scratch (step 101), and when the measurement result exceeds a predetermined level (step 102)
, it is determined that the downlink P-CH cannot be used normally. Then,
Based on the command from the CPU 20, the frequency tAm unit 24 performs the frequency υ1 corresponding to the specified A-C)-1, and the transmitter 23 transmits the downstream P by this upstream A-CS-4.
-C) The base station 1 is notified that the usage status of l is abnormal (step 103). Here, when the downlink P-CH is abnormal as described above, the mobile wJ station 2 notifies the base station 1 of the abnormality on the A-CH uplink, but in this case, each mobile station 2 The notification will be sent to station 1 all at once, so leave it as it is and go to 1. Collision of i signals may occur. In order to avoid this, in this example, the time at which the mobile station 2 notifies the base station 1 of an abnormality has a certain width. For example, move! Packet collisions are avoided by dividing the LJ station 2 into several groups and changing the delay spacing to the middle of the groups. .

Note that measures to avoid the above-mentioned signal collision can also be taken as follows. That is, first, the 1IlltI channel for notifying the abnormality is connected to A-CI-1 upstream and P-C
Avoid packet collisions by using both I and 1 uplink III control channels. Second, to notify the base station 1 of an abnormality, a communication channel is used instead of a control channel. In this case, the 8D station 2 records in advance the communication channel used for abnormality response using broadcast information,
The base station 1 constantly monitors the mobile station 2 through a communication channel broadcast to the mobile station 2.

When notifying the base 81 that the transfer *82 is abnormal, this is done after confirming that the communication channel is not in use.

While the above-mentioned processing is being carried out on the mobile side 1o82, the base 81 normally leaves the station (step 200), but the outgoing tIIJ! 211 transmitter/receiver! F1
2 receives the notification of the above abnormality on the uplink A-CH, and the fact is transferred to the CPU 20 (step 201), C
The PU 10 issues a downlink P-CH switching command. Having received this switching command, the transmitting/receiving device 12 for transmitting IIIJllll transmits the P-CH to the mobile station 2 on the downlink A-CH.
A downlink switching command is transmitted (step 202). Further, receiving the switching command from the CPLj 10, the incoming call control transmitting/receiving device 11 switches the downlink P-CH to a new frequency (step 203), and from now on, this switched downlink P-CH)! The 1lJlall signal is transmitted to the mobile station 2.

In the mobile station 2, the receiving unit 22 receives the switching command from the base station 1 on the downlink A-OH, and this fact is sent to CPtJ2.
0 (step 104), the CPU 20 issues a downlink P-CH switching command. Then, the frequency word tll Ff! 24 switches the downlink P-CH with the abnormality to a new frequency (step 105).

If the downlink P-CH becomes abnormal as a result of the above processing, that state is avoided and a normal communication state is maintained.

Note that in the above process, the downlink P −
The CH switching is performed by a switching command from the base station 1, and this switching command is caused by an abnormality determination in the transfer 1113ji2. In the end, the switching of the downlink P-C)l in the mobile 82 is caused by an abnormality determination at the mobile station.

In the case of an abnormality in the uplink control channel FIG. 5 is a flowchart 1 showing communication υ control in the case of an abnormality in the uplink υ1 channel.

On the base station 1 side, the transmission control transmitting/receiving device 12 always sends the upstream A-CI-1 control signal to V? monitors and transfers its status to CPUO. The CPU 10 measures the number of errors in the lung suppression signal based on the self-illumination of a predetermined specific pattern of the control signal (step 205), and when the measurement result exceeds a predetermined level (step 205).
06), it is determined that the upstream A-CH cannot be used normally. Then, an uplink A-CH switching command is issued from the cpuio. Upon receiving this switching command, the incoming call control transmitting/receiving device 11 transmits a control number 4n according to the no-one as shown in FIG. 6, for example, on the downlink P-CH to the mobile station 2 (step 207). The signal shown in FIG. 6 includes a common control information portion C that broadcasts information common to mobile stations;
an incoming call information part PI-PN for controlling an incoming call signal;
Furthermore, tIIJ for switching the control channel of the mobile station.
It consists of a channel switching command part S. In addition, the transmitting/receiving device 12 for the originating Ill IEI that received the switching command from the CPLIIO switches the upstream Δ-CH to a new frequency (step 208), and thereafter receives reception from the mobile 82 on this switched upstream A-CH. Do this.

Transfer station 2 is in a normal holding state (step 1oo)
, in this state, the base station 1
1lJ12I of Noornts 1~ shown in Figure 6 from the side!
The receiving unit 22 receives the signal, and the information is transferred to the CPU 20. Then, when the CPIJ 20 recognizes the control channel switching command S (step 110), this CP
Starting from tJ20, a 1-CH switching command is issued. Then, the frequency control unit 24 switches the uplink A-CH to a new frequency (step 111).

Through the above processing, even if the upstream Δ-CI-1 becomes abnormal, that state is avoided and a normal communication state is maintained.

In addition, in the above process, the switching command from base station 1 to mobile station 2 corresponds to a notification of uplink A-CH abnormality determination, and the switching command from base station 1 to mobile station 2 corresponds to a notification of abnormality determination of uplink A-CH, and it Then, the movement 82 switches the uplink A-CI.

In addition, in the above processing, channels are switched based on interference waves and the number of errors in control signals caused by equipment abnormalities.In particular, we pay attention to interference waves, measure the reception level of interference waves, and It is also possible to switch channels based on the measured level.

Next, packet communication υ-bis in ISDN includes:
There is a B-CI-1 packet using B-Cth packets and a D-CH packet using DO8. D in mobile communications
As an h method for realizing -C11 packets, there is a method using the A-CH upstream, which is a control channel for mobile communication. In packet communication services, the signal length of packet signals can be varied, so there are cases where a mobile station sends out a packet signal with a long signal length. In this case, calls and packet signals from other mobile stations cause signal collisions at the base station. A method to avoid this will be explained below.

FIG. 7 shows communication 1111 in case of uplink control channel abnormality.
It is a flowchart which shows j. This control is also performed in the same way as described above. For both mobile stations 2 and 2, this is carried out by each department in charge based on instructions from CPL Jlo, 20.

The base station constantly monitors the upstream A-CH traffic (step 210), and when a packet signal with a long signal length is sent by A-C1-1, or A-C)l
When the traffic of 'F]11g1 increases temporarily and the processing amount exceeds the specified value, normal use is disabled (Step 2).
11). Then, the base station checks the A-CH that can be switched based on the traffic and other conditions regarding other channels (Step 212), and uses the empty P-CH to switch the A-CH.
The A-CH switching instruction is issued to the mobile station only during JFfE when the amount of processing exceeds the specified value (step 21).
3). The mobile station is in a normal holding state (step 100).
), upon receiving a switching instruction from the base station side (step 11o), the uplink A-CI.
Switch 1.

After instructing the mobile station to switch A-CH as described above, the base station switches to the upstream A-CH, which has also been confirmed to be normal at its own station (up 214).
).

By the above processing, when the packet signal length on the uplink A-CH becomes longer or the traffic increases and becomes unsuitable for use as it is, this situation is avoided, and i
[Normal communication status is maintained.]

Note that in the above processing, there is a relatively high probability that an increase in traffic will occur on other channels as well, so step 2 is particularly
At step 12, the normality of the uplink A-CH to be switched is confirmed. This prevents unnecessary channel switching.

[Efficacy of invention Song Dynasty]

As explained above, according to the present invention, even if the control channel of either the mobile station or the base station cannot be used normally, if the control channel cannot be used normally, the control channel can be switched to another control channel. Therefore, it is possible to avoid a situation where the v1wJ channel cannot be used normally, and a normal communication state can be maintained at all times.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the principle configuration of the present invention, FIG. 2 is a block diagram showing an example of the basic configuration of a base station, FIG. 3 is a block diagram showing an example of the basic configuration of a mobile station, and FIGS. FIG. 5 is a 20-chart showing an example of communication fI11m, FIG. 6 is a diagram showing an example of the P-CI' upstream signal format, and FIG. 7 is a noro-chart showing another example of communication i control. be. 1... Base station, 2... Mobile station, 3... Determination means,
4... Notification means, 5... Channel switching means, 1
1... Transmitting/receiving device for incoming subwoofer, 12... Outgoing ♂11
Sr transmitting and receiving device, 13(1) to 13(i)...Communication transmitting and receiving device, 10.20...Central processing unit (CPL)
I), 22...receiving section, 23...transmission (8 copies, 24...
...Frequency control section. Basic configuration of base station 11 ML5 - Block diagram showing FIG. 2 0 Principle configuration diagram of the present invention FIG. 1 Block diagram showing an example of basic configuration of a mobile station FIG. 3 Flowchart showing -13'lJk of mobile station base station communication control P -CH
FIG. 6 shows an example of a downlink signal format. A flow chart shows an example of mobile station base station communication control. FIG. 6 shows a flow chart showing an example of mobile station base station communication control.

Claims (2)

[Claims] (1) In a mobile communication control system consisting of a base station and a mobile station under the base station, the base station and mobile station each have a plurality of bidirectional control channels for setting communication channels. The station and the mobile station have a determination means for determining whether the control channel in use can be continuously used based on the reception state, and a means for notifying the partner station of this fact when the determination means determines that the control channel cannot be continuously used. and a notification means for controlling the control channel to be used in a predetermined manner based on the determination or notification when the determination means determines that continued use is not possible or when there is a notification from the notification means on the partner station side. 1. A mobile communication control system comprising: control channel switching means for switching between channels. (2) The mobile communication control system according to claim 1, wherein the control channel switching means switches to the control channel after confirming that the control channel to be switched is usable.