JP3079895B2 - Mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to zone control in mobile communication such as a digital mobile communication system.

[0002]

2. Description of the Related Art For example, in the "traffic distribution method by radio base station output control" disclosed in Japanese Patent Laid-Open No. 05-063635, as a conventional example, an EIA which is a specification of a cellular mobile radio communication system is generally used. Departure /
The incoming call procedure (call connection control) is explained, and its drawbacks are pointed out. The contents are shown below. FIG. 29 is a diagram showing an example of each service area of a plurality of radio base stations constituting the cellular mobile communication system.

[0003] When a mobile telephone terminal (hereinafter referred to as ML) performs an outgoing or incoming call response operation, a radio base station 50 is called.
If there is a communication channel (hereinafter, referred to as Sch) owned by the ML (hereinafter, referred to as FB50), the ML can allocate a Sch in the FB and realize a communication service. Empty Sch
Does not exist, the FB 50 directs the ML to the ML on a downlink control channel (hereinafter referred to as Cch).
Send a Retry signal, which causes the ML to send FB5
Non-zero tunable FBs 51, 52, 53, 54, 5
After re-capturing and tuning any of the downstream Cchs broadcasted by the broadcast receivers 5 and 56, the re-selected F is retransmitted by resending a call request or an incoming call response on the re-selected upstream Cch.
The call service is realized by assigning Sch of B.

[0004] In addition to the technique disclosed in Japanese Patent Application Laid-Open No. 5-63635, there are techniques shown in FIGS. 30 to 34 as a prior art. The prior art will be described below. In FIG. 30, 1 is a mobile switching center (hereinafter referred to as CC) and 2 is ML
(Basically the same as the conventional mobile terminal), 50 to 5
2 is an FB (basically the same as a conventional base station),
500 to 520 are service areas, which indicate control zone areas of FBs 50 to 52.

Next, the operation will be described. Normally, the CC controls a plurality of FBs, executes an outgoing / incoming call sequence on the Cch to the ML located in the zone, and gives the Sch of the zone to start a call. The ML in the zone normally receives the downlink Cch transmitted from the FB of the zone. Downstream Cch is a flow of package information in which a frame is cut and a frame number is added to the beginning. One frame is composed of "signal type" indicating what meaning it has, "zone number" indicating FB number, and control information such as incoming call, call response, and call channel instruction.

In this downlink Cch, it is assumed that the number of the Cch in the zone around the zone is periodically transmitted as a notification signal in advance as information. As a result, the ML captures the Cch of the zone, establishes frame synchronization, and
The Cch information of the peripheral zone can be obtained as a code indicating the frequency of the Cch used in the peripheral zone from the broadcast signal in which the information of the channel can be read, and the Cch of the peripheral zone can be known in advance. it can.

[0007] In addition, in the incoming call signal that is sent to the downstream Cch when calling the ML located in the zone, in addition to the number of the ML to be called, it is simultaneously determined whether the Sch of the zone is currently usable or not. Shall be shown. This allows the ML to know whether there is a Sch in the zone when receiving an incoming call.

FIG. 31 shows an example of an algorithm in which the ML fetches the Cch information of the peripheral zone reported on the above-mentioned downlink Cch. The ML captures the downlink Cch (S31
1) After the frame is synchronized and the information can be read (S312), the notified peripheral Cch information is fetched (S313). After the data has been completely captured, the current Cch is temporarily removed, and the information of the captured Cch is sequentially measured to determine in which zone the downlink Cch can be received and at what electric field (S314). C in the surrounding zone
After the measurement of the channel is completed, the result is rearranged inside the ML in the order of easy reception (in the order of strong electric field) from the result. This rearranged list of downlink Cch is called a best list.
After the creation of the best list (S315), the Cch that has been initially captured, that is, captured first, and the Cch that has received the neighboring Cch information is captured,
It enters a normal operation state (S317). In addition, if the ML moves and cannot receive the downlink Cch of the zone,
Alternatively, if there is no Sch in the zone at the time of outgoing / incoming call, the Cch acquisition operation is performed from the one that is easy to receive based on the best list (that is, from the best 2) (S316).

In the algorithm of FIG. 31, a best list is created when Cch is first acquired. Therefore, M
Depending on the moving situation of L, for example, Cc
h is likely to expire, so the best 2 Cch is captured according to the best list. However, in practice, if the Cch below the 2 best can be better received by movement during that time, the actual Strongest (best)
A situation occurs in which Cch cannot be received. In order to solve the problem, a method shown in FIG. 32 can be considered. Switch Cch according to the best list and select Cc around
After capturing the h information (S323), when measuring the electric field of the peripheral Cch, it is checked whether there is any Cch that can be received with an electric field stronger than the first switched Cch (S325). Otherwise, the best list is created as shown in FIG. 31 as it is (S327), or if there is a Cch that can be received better, the Cch is switched to the stronger Cch (S326), and the fetching of neighboring Cch is performed again. By taking a measurement,
This is to capture Cch, which has the strongest electric field in reality.

Next, a sequence showing how the ML actually located in the congested state receives an incoming call and leads to a call will be described with reference to FIG. When calling the ML in the congestion zone, the CC transmits an incoming call signal together with the ML number in the incoming call frame, indicating whether or not there is a Sch in the zone. Upon receiving this, the ML recognizes that there is no Sch in the zone, searches for a Cch that can be captured from the internal best list, and calls the incoming call in this zone on the upstream Cch of the Cch that has been captured. Request to CC. The CC again sends an incoming call signal in the zone receiving the incoming call request. If there is a Sch, the ML returns an incoming call response and the CC
Is given Sch and leads to a call. After the end of the call, the ML enters the Cch reception state of the zone, and the C
The channel information is fetched, and the best Cch is captured again by the algorithm shown in FIG.

[0011]

In the call connection procedure according to the above-mentioned conventional example, at the time of an incoming call, first, "calling" of a downlink Cch is performed.
ML has an incoming call response, and Dir
A signal called “ectedRetry” is transmitted to the downlink Cch, and in response to this, the ML performs control from Cch reselection to retry. Therefore, there are the following specific problems. a. In the algorithm as shown in FIG. 31 and FIG. 32, the ML separates the Cch currently acquired and performs a search operation of the reception level of the electric field of the downstream Cch in another zone.
During this search period, the CC and the ML cannot communicate. b. Until the time until the retry of the ML, there is no guarantee that the connection is always established, but the caller is put on hold (time when connection is possible or uncertain or uncertain). c. Further, a complicated sequence as shown in FIG.
Increase the traffic of ch. Further, for example, there is a restriction on the number of bits and the number of frames on a signal frame (format) on the Cch in advance, and congestion cannot be notified at the time of information on an adjacent Cch or an incoming call, or a unit of an incoming call for a plurality of zones. In this case, the congestion zone processing is executed when the zone that has received a response from the ML by receiving an incoming call to a plurality of zones once, and the sequence between the ML and the ML increases, thereby increasing the traffic. The above a. ~ C. In addition to the problems described above, the prior art has not been able to adequately grasp the position information of the moving object, suppress repetition of the handover operation, and the like. As described above, the conventional technology has a problem that smooth and efficient operation cannot be sufficiently achieved.

The present invention has been made to solve the above problems, and has as its object to provide a mobile communication system capable of performing smooth and efficient operation.

[0013]

According to the first aspect of the present invention,
When the mobile switching center sends an incoming call within the congestion zone,
The mobile unit performs an operation of avoiding the congestion zone, and the mobile switching center notifies the calling party that the zone switching is being performed by the notification unit.

According to a second aspect of the present invention, in addition to the first aspect, an electric field of a control channel in a peripheral zone is measured based on information on the peripheral control channel, and a list of control channels is prepared based on the measurement result. It is intended to be created.

According to a third aspect of the present invention, in addition to the first aspect of the present invention, a control channel having an electric field stronger than that of the control channel initially captured is re-captured, and peripheral control channel information is read from the control channel. It is intended to be performed again.

According to a fourth aspect of the present invention, before the mobile switching center transmits an incoming call within the congestion zone, the mobile station exchanges the electric field of the uplink control channel of the congestion zone with a base station in a zone surrounding the zone in advance. By instructing measurement and measuring the electric field of an incoming call response transmitted to the uplink control channel of the mobile unit with respect to the incoming call, the surrounding area where a call can be made
The communication channel of the zone is instructed to the mobile unit .

According to a fifth aspect of the present invention, an uplink electric field of a mobile unit during a call in a congested zone is measured by a base station in a surrounding zone, and an instruction to shift to another zone based on the measurement result after the call is completed. It is something to do.

According to a sixth aspect of the present invention, there is provided a data table for managing a moving object, wherein the data table includes:
It has a traffic level determined based on the number of outgoing / incoming calls per unit time and the time when each mobile body last made or received a call as a parameter .
From inside, the traffic on the above mobile management data table
Articles registered in advance from the level and last access time
It is obtained as to extract a particular mobile in the matter.

According to a seventh aspect of the present invention, in addition to the sixth aspect of the present invention, the mobile unit that instructs the extracted mobile unit to shift to the surrounding zone, and switches the extracted mobile unit when the mobile unit receives the shift instruction. The control channel is switched to a control channel of a possible peripheral zone.

[0020] The invention according to claim 8 is the invention according to claim 6, wherein the extracted uplink electric field of the moving object is measured by a base station in a zone around the extracted moving object, and the measured result is added to the measurement result after a call is terminated. <br/> Ru Oh in what was to indicate the transition to the peripheral zone based.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. In the call connection sequence as shown in FIGS. 30 to 33, in order to process a call to the ML located in the congestion zone, it is necessary to process the call as a single call processing. When moving, a Cch acquisition operation is performed, but during this time, it is not possible to communicate with the CC, and it is uncertain how long the so-called “screaming” state will continue until communication with the CC is possible again.
During this time, the caller is simply put on hold. It is not very desirable in terms of serviceability that the surrounding zones are also congested, that the Cch acquisition operation takes too long, and that the caller is kept on hold for a long time without connection guarantee.

[0022] Example 1 configured as shown in FIG. 1, it is similar to the configuration basically in FIG. 30 described above, bets on CC
Key trunk TT is connected,
In rank 100 , two types of talkies, a talkie 1 and a talkie 2, are incorporated as audio files, which are indicated by T1 and T2 in FIG.

The operation of the first embodiment will be described below with reference to FIG. In the first embodiment, in the incoming call connection sequence, the ML receives the incoming call (there is no Sch empty) and searches for Cch from the best list. It provides a talkie service to the effect. In FIG. 2, the CC sends an incoming call (without Sch empty) to the ML, and at the same time, uses the talkie 1 to call the caller. "Since the ML zone is currently congested, the ML is performing a zone switch. . "
We perform talkie service of contents. If the ML has not successfully captured Cch in another zone even after a certain period of time has elapsed, a talkie service is provided by the talkie 2 which states "Please call again after a while." The caller hears this and disconnects,
Call back again. On the other hand, if the ML immediately executes the Cch switching operation during this time and can switch to another zone, the CC stops the talkie 1 and plays a ringing tone (RBT) to the calling party, thereby allowing the calling party to switch to the ML. Recognizing that the call was successful, if the telephone is held as it is, the call will be made soon. When the caller who has been disconnected once again calls again, the ML can talk in the switched zone in terms of time. The best list is created by the ML based on, for example, the algorithm shown in FIG. 31 or FIG.

Embodiment 2 FIG. In the above-described first embodiment, an example is shown in which the mobile station leaves the congestion zone by the ML Cch acquisition operation.
By the control of the (FB) side, a call is reached in a manner similar to a general incoming call operation without the ML Cch capturing operation. Hereinafter, description will be made with reference to FIGS. FIG. 3 is a schematic diagram showing a state in which the ML2 located in the congestion zone FB50 receives an incoming call and returns an incoming response to the FB50. The electric field of this upward Cch of the ML2 also reaches the FB51 and the FB52. Is represented. The sequence of the one shown in FIG. 3 will be described below with reference to FIG. When an incoming call is to be made to the ML located in the congestion zone, the CC first instructs the surrounding zones FB51 and FB52 of the zone FB50 to measure the electric field of the upward Cch of the FB50 (S41). An incoming call is made from the FB 50 whose location is currently registered to the ML. The ML returns an incoming call response on the upstream Cch of the FB 50.
1. The FB 52 performs measurement and notifies the CC of the measurement result of the uplink electric field level. CC is based on this result (S42),
The Sch of the zone where the electric field was the most other than the congestion zone was F
The ML is instructed on the downlink Cch of B50 (S43). ML
Shifts to the instructed Sch (S45), leading to a call.
The series of operations shown in FIG. 4 is a general incoming call operation for the ML. This operation returns a response to an incoming call, is instructed by a Sch which can talk, and leads to a call on the Sch. It does not come off.

Embodiment 3 FIG. In the second embodiment, an example in which the electric field of the upstream Cch of the ML is measured has been described. When focusing on one telephone terminal, it can be said that the probability of using the telephone terminal immediately after one call is high. For example, there is a case where a call is received and then another place is called this time depending on the contents of the call. In the third embodiment, in consideration of the above points, the ML during a call in the congestion zone is shifted to the surrounding zone at the end of the call, so that even if a call is continuously made, the calling is performed from the surrounding zone. will want to call, the zone is one that was so as to avoid things like return immediately or congestion zone. Originally, to perform handover processing, F
It is common that B has a device for measuring the uplink electric field of the ML during a call. FIG. 5 shows an example in which a zone is switched after a call based on a measurement result of an uplink electric field of a ML during a call.
Shown in The CC instructs the surrounding FBs to measure the uplink electric field of the ML (the number of Schs is present because of congestion) during a call in the congestion zone (S51). In a general handover process, when the uplink electric field of the ML during a call in the zone falls below a certain threshold value, the measurement of the electric field of the ML is started in the surrounding zone in order to shift to the surrounding zone while the call is in progress. However, here, the measurement is instructed to the surrounding zones even if the threshold value is exceeded. The FB in each peripheral zone notifies the result of the measurement of the uplink electric field of the plurality of MLs to the CC order. The CC executes a call termination sequence with the ML that has ended the call first in the zone, and finally instructs the shift to the zone with the highest electric field based on the measurement result (S52). The ML that has received the transfer instruction transfers to the designated zone and performs location registration.

The shifted ML may or may not continue to make a call. However, even if a call is made, the operation from the call to the call in the surrounding zone is performed.
The original zone does not immediately return to the congestion zone again. Also, even if another ML originates / receives a call and the original zone is congested, the M
Since the upstream electric field in the peripheral zone of L has already been measured, only the upstream electric field of the ML that is newly talking needs to be measured in the peripheral zone as described above. In this way, the ML during a call in the congestion zone is shifted to the surrounding zone after the end of the call to reduce the probability that the ML may be re-entered in the congestion zone.

Embodiment 4 FIG. As a conventional example, there is a configuration in which the ML performs Cch switching to a peripheral zone by reporting a congestion state on a downlink Cch. Such a configuration has the following problems. a. All MLs located in the zone are almost all
Channel switching → Cc of peripheral zone to execute location registration
h Traffic rises at one point. b. Once congestion occurs, in that zone, all MLs other than during the call move to the surrounding zone, and even if the congestion is released, the distribution of the MLs becomes unbalanced. In the fourth embodiment, the above problem is solved.
The CC has a data table for managing the ML as shown in FIG. 6, and selects only a specific ML from the table, and causes the ML to execute zone switching.

The features of the table shown in FIG. 6 are that it has, as parameters, the last access time when each ML originated / received the call and the traffic level calculated based on the number of accesses during a certain period. It is. For example, if the number of outgoing / incoming calls for three days is set as the traffic level, the level of the traffic level indicates the high usage rate during the past 72 hours. Also, the last access time is a measure of recent usage. Even if the traffic level is the same, if no access has been made during the past 24 o'clock, it is estimated that the usage peak has passed, and if it has recently been used, it is estimated that the peak is approaching.

The above a. ML located in the zone
Operation of extracting b. An operation of arranging the extracted MLs in the descending order of the usage rate based on the traffic level and the access time, c. A series of operations such as an operation for estimating a peak are executed by software. Then, a. ,
b. The number of devices to be extracted and arrayed is registered in advance in the form of "data setting (registration)" as a system parameter.

FIG. 7 shows a sequence in which the traffic level of each ML is calculated in the manner described above and a specific ML is shifted to the surrounding zone. When the zone of the FB 50 becomes congested, the CC searches the ML data table shown in FIG. 6 to find out the ML located in the zone. As described above, among the MLs located in the zone, a process is performed to extract an ML that has a high traffic level and is likely to have a high usage rate at the present time, such as a recently used one (S71). In this case, a transfer instruction for the ML is sent in a specific frame of the downlink Cch of the FB 50. The ML that has received this searches for the neighboring Cch in the best list, registers the location in the peripheral zone, and moves to the peripheral zone (S72). As a result, when the ML performs outgoing / incoming calls, it is avoided from the congestion zone. It is assumed that the ML has created the best list based on, for example, the procedure shown in the algorithm in either FIG. 31 or FIG.

Embodiment 5 FIG. Fourth Embodiment In the fourth embodiment, although no call is made at the present time, an example is shown in which the CC identifies an ML with high traffic and performs zone switching, but an ML already in a call state may have a high traffic at that time. Because of the large number, it may be desirable to shift the ML to a peripheral zone with lower traffic after a call. In the fifth embodiment, when the ML during a call ends the call, it is shifted to a peripheral zone, as shown in FIG. For the ML during a call in the congestion zone, the CC extracts the traffic level described in the fourth embodiment from the table (S81). In particular, as described in the third embodiment, if it is considered that the ML in a call state has a high probability of continuing to make / receive a call even after the end of a call, the traffic level does not need to be extracted and the ML is terminated as in the third embodiment. The transition may be forcibly made after the talk. However, if it is determined that the traffic level is the same as other MLs based on the traffic level, it is determined whether the traffic level is the high traffic level by the method described in the fourth embodiment. Judge. When the ML to be shifted is busy, the peripheral zone is instructed to measure the Sch-up electric field of the corresponding ML as in the third embodiment (S8).
2). In this case, there is no need to measure the uplink electric field of all MLs that are talking in the congestion zone, and only the target ML is measured, which is different from the third embodiment. Each peripheral zone notifies the CC of the result of the measurement of the uplink electric field. C
C executes a transition instruction to the ML after executing the call termination sequence based on the measurement result (S83). The ML that has received the transfer instruction executes switching to the instructed peripheral zone and performs position registration (S84).

When the MLs move to the peripheral zone all at once, the Cch traffic in the peripheral zone may suddenly rise. In this case, in reality, even if there is an empty space in the Sch, the outgoing / incoming signal is difficult to pass due to the signal congestion on the Cch, so that the operation is close to the congestion where it is difficult to communicate. Specifically, a failure occurs in the Cch of the zone or a case where maintenance is performed corresponds to the case, and the zone cannot be used. What avoids this
Is shown in FIG. In the peripheral zone, when the ML suddenly moves and a position registration sequence is performed, one Sch is temporarily used exclusively for position registration.
This avoids giving a traffic-like impact to the operation of the normal Cch. FB5
0 indicates failure or Cch in maintenance
Stop, the ML20 located in the zone,
21 needs to switch to the peripheral zone. ML
Detects the degradation of the electric field of the downlink Cch (or receives a signal indicating that the downlink electric field is emitted and the zone becomes unusable because it enters the maintenance state), and the number of channels of the receiver is switched to change the electric field of the electric field. A certain channel is searched, and a receivable channel is selected.

On the other hand, in the CC, when a failure (or maintenance) of the FB 50 occurs, control is performed such that one Sch is used as a temporary Cch exclusively for the position registration sequence for peripheral zones such as the FBs 51 and 52. The ML that has switched the zone performs location registration in the S1ch of the FBs 51 and 52, and after the location registration sequence ends, the normal Cc of that zone.
h Entering the capture state. In CC, a certain time (ie, F
After a lapse of a sufficient time until the ML at B50 moves to the peripheral zone), the S1ch of the FBs 51 and 52 is returned to the normal S1ch (call channel) operation.

As described above, ML is the temporary Cc of the peripheral zone.
When h (Sch) is acquired and location registration is performed, if a frame pattern different from the frame pattern used in the normal downlink Cch is used when the temporary Cch is used,
When the ML captures a Cch, the ML can recognize whether it is a normal Cch or a temporary Cch. FIG. 10 shows a frame pattern of the downlink Cch.
Show. The situation as described above, that is, Cch of a certain FB
In the case where a failure (or maintenance) occurs in the zone and the Cch of the zone is stopped, the basic operation of temporarily using the Sch of the peripheral zone as the second Cch is as described above.
Same as the example . At this time, as shown in FIG.
A frame pattern (Fa, Fb, Fc...) different from the ch frame pattern (F0, F1, F2...) is used for the temporary Cch (S1ch).

FIG. 11 shows the ML Cch acquisition algorithm. When moving between zones in an ML that is operating (moving) normally, the reception electric field level of the downlink Cch gradually deteriorates (before the Cch is separated, a certain reception electric field level before the Cch is separated). Deterioration is detected.) However, since the failure occurs suddenly, the received electric field disappears suddenly. Alternatively, the frame pattern suddenly disappears. At the time of maintenance, it is also possible to notify in advance that maintenance is to be performed to all MLs in the zone in the downlink Cch, and to issue a notification prompting the transition to the ML to the surrounding zone. When the descending Cch disappears suddenly or when a simultaneous shift command or the like is received (S11),
When the electric field is searched (S12) and the electric field of Sch is detected, a frame synchronization pull-in (synchronization detection) operation is performed (S14). The frame synchronization detection is performed on the frame patterns (Fa, Fb, Fc...) Used in the temporary Cch, and the synchronization detection is not performed on the different frame patterns. Recognize that it is used for the call, and
To skip. If there is an electric field and the frame pattern also captures the Sch for the temporary Cch, the ML performs position registration (S15). When the surrounding Sch cannot be captured due to the electric field state, there is a high possibility that the Cch in the normal operation cannot be captured, but the normal Cch capturing operation is executed as the operation (S16).

Next, a specific example of a mechanism for detecting frame synchronization will be described with reference to FIGS. 12, 13 and 14. FIG. This frame synchronization detection method can simultaneously perform detection processing of two or more different frame patterns. FIG. 12 shows the configuration of the frame synchronization detection circuit, and the cpu or LS
It comprises a frame synchronization detection processing module 7 (hereinafter referred to as FDET) comprising a group of logic circuits converted into I, and a data storage RAM 8 (hereinafter referred to as RAM) accessed by the FDET. The FDET 7 monitors a digital signal on a wireless channel called Sch or Cch, is started (START / STOP) from the outside, and outputs presence / absence of establishment of frame synchronization, frame timing, a reception frame number, and the like. FIG. 13 shows an algorithm for detecting frame synchronization. FDET7 is activated (S131).
Thereafter, the RAM: 8 is cleared (S132), and the monitored signal is received and analyzed one bit at a time. When 1 bit is received, it is checked whether the past 8 bits match any of the frame patterns (S1331). When the frame pattern is not a frame pattern, 8-bit data having a data structure as shown in FIG. 14, that is, a bit indicating OK or NO in the frame pattern check is set to 0: NG and a frame pattern type and a frame number are set to "0". Write to RAM8. If it matches the frame pattern, the check bit is set to 1 (OK) and written into the RAM 8 together with the type of the pattern and the frame number (the first half of S1334 so far). In the case of a true frame pattern, the number immediately before the frame type must have been received just one frame before, so this data is read out (the latter half of S1334) and checked. When the temporary Cch frame pattern must be detected at the time, it is determined that the frame pattern is not the temporary Cch frame pattern (Yes in S1335).
Therefore, the past frame pattern withdrawal check is stopped. When several frames of the temporary Cch frame pattern are received (S1336) and the frame synchronization probability condition (whether or how many frames can be received as a frame pattern) is satisfied (S1337), frame synchronization is established for the first time. With this, when a normal Cch electric field is captured and captured, at the time of bringing in frame synchronization (that is, when only one or two frames are received), it is determined to be a normal Cch, and a channel having another electric field is searched. Can be performed.

Once the frame synchronization is established, even if the data is switched to the new frame synchronization data until the frame synchronization loss condition (whether or not which frame does not match the frame pattern) is satisfied. The old frame is protected. Here, an example is shown in which even during the protection of the old frame , the frame synchronization timing can be switched earlier by an algorithm that switches when a new frame is received. FIG. 15 shows an algorithm when frame synchronization is being established (missing monitoring mode).
The process of checking whether or not the past 8 bits match the frame pattern each time 1 bit is received (S151) and the data configuration when storing the result in the RAM 8 are the same as in the eighth embodiment. If not coincident with the frame pattern, it is checked whether or not it is time to receive the frame pattern (S152).
At that timing, it means that one frame pattern that is currently being synchronized does not match, so it is determined whether or not the out-of-synchronization condition is satisfied (S15).
3). (If they are satisfied, the synchronization is lost (S154)). If it matches the frame pattern, it is checked whether it is received at the timing when synchronization is established (S155). If it matches, the data is simply stored as the frame pattern as it is (S155). S15
6). If it is not the timing, the data received in the past at the timing received now is reviewed, and it is checked whether or not the number of frames satisfying the frame synchronization establishment condition has been received (S157). If the frame synchronization establishment condition is satisfied, furthermore, in the frame synchronization currently being established, although the frame pattern of some recent frames does not match, the synchronization mode is still not satisfied and the protection mode is not satisfied. It is checked whether or not (S158). In the protection mode, by switching to the timing of the new frame synchronization at this point, it is possible to switch to the new frame synchronization earlier by the number of protection frames under the out-of-sync condition (S159).

In the above-described example, when the Cch of the FB 50 has a failure (or maintenance), the ML of the zone moves to the surrounding zone. In FB50,
When only the Cch is faulty and another Sch can be used, or during maintenance, it is normal and the Sch is normal.
Should be usable. In such a case, FIG. 16 shows an example in which the Sch in the maintenance zone is used when the congestion occurs in the surrounding zone. An outline of the sequence shown in FIG. 16 will be described below with reference to FIG. FB
50 Cch in maintenance state, and FB50
FB5 when the other Sch is ready for normal use.
2 becomes congested (S171), then the FB 52
In the case where a call is made / received to ML2, CC becomes FB5
The ML 2 is instructed to talk on the FB 50 Sch on the downstream Cch 2. Depending on the position in the zone of ML2, FB5
In some cases, the radio wave does not reach 0 and the call cannot be reached, but if it does, the ML 2 shifts to the instructed Sch (S172), and the call can be made even if the original zone FB52 is congested (S172). S173).

In the above-described third embodiment, an example has been described in which the upward electric field of the ML during a call is measured in the peripheral zone. Generally, in a mobile communication system, the position of an ML is managed,
As one of the maintenance and operation services, there is a service that provides ML location information to an operator, and the location information is in units of zones based on location registration information. Here, an example in which the approximate position in the zone is grasped based on the electric field measurement result in the peripheral zone as described in the third embodiment will be described. FIG. 18 graphically shows the results of measuring the electric field of the upstream electric field of the ML that is talking in zone A among the zones shown in FIG. Here, the electric field level is set to 10 levels, the level at which a sufficient electric field can be obtained in the zone is set to 8 or more, and in FIG. 18b showing the concept of the electric field level, a further upward electric field is measured within a dotted line. The vicinity of the boundary of the area is about level 5, and below this level, it may be considered that the CC performs the handover (zone movement during call) process. Now, if the electric field measurement result as shown in FIG. 18 is obtained, since it is level 6 in A which is the communication zone, it is presumed that ML exists near the boundary near the boundary. And the surrounding zone B
Looking at the levels H to H, since the zones B and G have the highest electric field of level 5, it can be inferred that the ML is located in the hatched area S in FIG. 18A. As described above, it is possible to grasp the position of the ML by dividing the circle representing one zone into areas divided by the number of surrounding zones.

In the above-described example, only the upstream electric field of the ML is used as a criterion. However, reliable information may not always be obtained depending on the radio wave condition, for example, when the ML enters a shadow of a building. Here, an example of observing the bit delay of the ML uplink signal will be described. FIG. 19 shows the bi of the ML upstream signal.
4 shows an image of a t delay. The FB always has a master frame timing in order to generate Cch and Sch frame timings. Normally, it is synchronized with the transmission network between CC and FB, and all FBs are synchronized with the entire system at the same timing. Now, by looking at how much the upstream frame timing of the talking ML is delayed with respect to the master frame timing in the talking zone and the surrounding zones, the relative number of delay bits indicates that the approximate We can grasp position.

In the above-described example, an example in which the approximate position in the zone is grasped has been described . Here, an example in which the position information obtained in the above-described example is displayed is shown in FIG. In FIG.
For example, in the personal computer 3 (hereinafter, PC), a zone and a division within the zone are displayed as image information in advance.
Alternatively, the map may be of a high function type in which the map is registered as image information and the area is displayed thereon. The CC 1 may simply address the position information to the PC 3 (for example, by area call or coordinate values) and provide the PC 3 with a display format. In this case, RS-232C which is a general PC interface can be sufficiently realized. PC3
Even if the function is not so sophisticated, a map such as MAP4 is created and a lamp such as an LED is provided at a location corresponding to the area position, and this lamp is turned on according to the address notified from CC1. Thus, a simpler display device can be obtained.

Incidentally, with respect to a general Cch capturing operation, for example, the following situation may occur. M
Normally, L once captures Cch, then captures Cc
Until the state where h cannot be received occurs, the Cch acquisition operation is not performed. Since there is an overlap of serviceable areas usually called overreach between zones, even if ML moves between zones, Cch does not switch immediately,
Continue capturing Cch as it is. In general, in terms of device configuration and performance, FB
The transmission power of the downlink radio wave is stronger, and the transmission radio wave of the ML is already F
Even if you move to a place where you cannot reach B, Cc
In some cases, the situation where h is continuously captured occurs. Next, FIG. 21 shows an example in which a mobile switch for performing the Cch acquisition algorithm is provided in the ML, and FIG. 22 shows the operation. Normally, the ML has a function of visually displaying the electric field level of the reception Cch on an LCD or the like. However, when the user determines that the electric field level currently being received is low, the Cch search manual operation on the operation button of the ML is performed. The switch 10 is pressed (S221). The ML whose switch is pressed searches for Cch as shown in FIG. 31 or 32 (S222). When a different Cch is captured, location registration is performed. As shown in FIG. 21, the switches 10 and 11 are located at the uppermost part of the plurality of switch groups, and another function switch is located between the switches 10 and 11.

Also, the ML is automatically set to C instead of the switch.
FIG. 23 shows an example of performing a channel search. In general, the descending Cc
As described above, the Cch search is started only after a state in which h cannot be received.
The electric field measurement is performed in a fixed time unit, and the Cch search is activated before the downlink Cch cannot be received. If the ML moves out of the zone normally,
Should gradually become weaker. Even if the electric field distribution fluctuates, the electric field measurement values within a certain time are averaged,
If the average value is sampled at regular intervals, it can be easily determined whether or not the electric field is deteriorating. The operations from the averaging of the electric field measurement values to the judgment of the electric field deterioration state are executed by so-called software processing. This electric field deterioration level is set slightly higher than the electric field level at which Cch cannot be completely received, and when the electric field deterioration level continues for a certain period of time (S231) in the processing for each elapsed time, for example, based on the algorithm of FIG. It is configured to start a Cch search (S232), and based on the start of the Cch search, the ML automatically captures an optimal Cch before falling into a level that cannot be received even when moving between zones.

In the above-mentioned example , the overreach between zones and the imbalance between the up / down electric fields have been described, but this also applies to the ML during a call. For example, as shown in FIG. 24, ML2 which is at substantially the same distance from FB51 and FB52,
Calls can be made using the Sch in either zone. Depending on the state of the electric field, for example, when a user crosses the shadow of a building or points an antenna at a shield, a handover (hereinafter referred to as HO) is activated depending on the timing. O returns to the original zone. H. O is a function of continuing the call state, but the call path is switched, so that an instantaneous interruption is always required. It is desirable that O does not occur.
In the case as shown in FIG. The O-suppression switch 11 is provided on the operation button of the ML so that the user can use the H.264 switch during a call. In a case where it is recognized that O is repeated and the user feels discomfort, this switch is depressed, and the ML issues an H.O to the CC. An O suppression request shall be made. The upstream signal of the ML during a call is a digital voice signal which is framed. For example, as shown in FIG. By applying the control signal to the O-suppression, the CC is transmitted from the upstream Sch on the H. O. Inhibition request is learned, and H. O processing is thereafter suppressed.
Note that in the frame format shown in FIG. 9 shows a control frame requesting suppression of O. Generally, a control frame is often transmitted continuously for 2 to 4 frames in consideration of a bit error on a wireless transmission path. Only one control frame for O suppression request is shown.

In the above-described example, the ML is operated by the manual switch.
To H. Although the example in which the O suppression request is raised has been described, the ML is replaced with the H.264 switch instead of the switch. The number of repetitions of O.O. When O repeat occurs, H.O. FIG. 27 shows an example of raising the O suppression request. In the ML during a call, H.264 switches the call zone from the CC. When the O process is performed, the H.O. Whether O was performed is stored together with the received electric field level at that time. H. between same zones In the case where O is performed a plurality of times, the ML notifies the CC of H. H request for the ML by making the O.Suppression request. O is suppressed.

In the above example, ML to H.264 are used. Although the example in which the O suppression request is raised has been described, an example in which the CC determines and suppresses the request is shown in FIG. In a state as shown in FIG. 24, ML2 is H. between FB50 and FB51. When repeating O, the CC transfers the call from any zone to any zone. O is managed, and the same ML H.O. When the O process has been performed a specified number of times or more (S281), the call (M
H. for L). Control for suppressing the O processing is performed (S282). It is more effective if the deterrence is performed in stages. For example, H. In case O makes one round trip between the zones and returns to the original zone, H.0 from the current zone is used as suppression stage 1. Make O difficult. That is, H. Decrease the criterion of the upstream electric field deterioration level of the ML during a call in the zone where the O process is activated. Then, the last time If the H.O. Since the O processing is not started, it is somewhat suppressed. In this way, H. H.O. If the criterion for starting O is lowered, H.O. O is deterred.

Although an example has been shown in which the above-described first to fifth embodiments are applied to so-called digital mobile communication, the present invention is also applicable to analog mobile communication.

[0048]

Claim 1 according to the present invention, in the third invention, since simultaneously CC and to the ML congestion zone avoidance operation notifies effect of "congestion" to the calling party, it is the service bi utility. According to the invention of claim 4 , since the CC (FB) side controls, the ML does not perform the Cch acquisition operation and can perform the same incoming call operation regardless of the presence / absence of congestion. Claim 5
In the invention of CC, the CC measures the uplink electric field of the ML during a call,
Since the shift instruction is performed outside the congestion zone, the ML does not need to perform the Cch capturing operation again after the end of the call. Claim 6,
In the inventions of 7 and 8, the CC at the time of congestion is not a zone unit,
Since managing the traffic state of the individual ML, it is not necessary to perform the switching large number of ML zones at once, Cch traffic is also not as high load.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a mobile communication system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a sequence of an incoming call in a congestion zone according to the first embodiment.

FIG. 3 is a diagram illustrating an upward Cch electric field of an ML according to a second embodiment.

FIG. 4 is a diagram showing a sequence of an incoming call in a congestion zone according to the second embodiment.

FIG. 5 is a diagram showing an ML transition sequence from a congestion zone in the third embodiment.

FIG. 6 is a diagram illustrating a data table regarding MLs possessed by a CC according to the fourth embodiment.

FIG. 7 is a diagram showing an ML transition sequence from a congestion zone in the fourth embodiment.

FIG. 8 is a diagram illustrating an ML transition sequence from a congestion zone according to the fifth embodiment.

FIG. 9: Avoidance of sudden Cch traffic in surrounding zones
The figure which shows the example which performs.

FIG. 10 is a diagram showing a downlink Cch frame pattern.

FIG. 11 is a diagram showing a procedure for acquiring a ML Cch.

FIG. 12 is a diagram illustrating a configuration of a frame synchronization detection circuit.

FIG. 13 is a diagram showing a frame synchronization detection procedure.

FIG. 14 shows data stored in a data storage RAM .
The figure which shows a structure .

FIG. 15 is a diagram showing a frame synchronization detection procedure.

FIG. 16 is a diagram showing a call in a maintenance zone.

FIG. 17 is a diagram showing a sequence.

FIG. 18 shows an uplink electric field measurement level of a ML during a call;
FIG.

FIG. 19 is a diagram showing a bit delay of a ML during a call;

FIG. 20 is a diagram showing a display example of ML position information.

FIG. 21 is a diagram showing an outline of the operation of the ML shape.

FIG. 22 is a diagram showing an outline of the operation of the ML.

FIG. 23 is a view showing an outline of the operation of the ML.

FIG. 24 is a diagram showing an outline of a call state of the ML.

FIG. 25. H. from ML . The figure which shows O suppression request.

[26] H. Signal format for O suppression request
FIG.

[Figure 27] H. FIG. 7 is a sequence diagram showing an example of O suppression.

[28] H. FIG. 7 is a sequence diagram showing an example of O suppression.

FIG. 29 is a diagram showing a configuration of a conventional mobile communication system.

FIG. 30 is a diagram showing an outline of another conventional mobile communication system.

FIG. 31 is a diagram showing a procedure for creating an example of a Cch best list in the one shown in FIG. 30;

FIG. 32 is an exemplary view showing a procedure for creating another example of the Cch best list in the one shown in FIG. 30;

FIG. 33 is a diagram showing an incoming call sequence of a congestion zone in the mobile communication system shown in FIG. 30;

[Explanation of symbols]

1 CC (Mobile Switching Center), 2 ML (Mobile), 50
-52: FB (wireless base station), 500-520: service area, 100 TT (talkie trunk).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 H04Q ⁷ /06-7/38

Claims (8)

(57) [Claims] A mobile communication system comprising: a service area constructed by a plurality of radio base stations; one zone having a control channel for performing call connection control for a mobile body in the zone and a communication channel; In the body communication system, the server
When one zone of the service area is a congestion zone, when the mobile switching center transmits an incoming call within the congestion zone,
Mobile communication system mobile switching center with the mobile performs avoidance operation from the congestion zone and notifies the notification means that is in switching zone to the calling party. 2. When a mobile unit located in a zone captures a control channel of the zone, the mobile unit measures an electric field of the control channel of the peripheral zone based on information of the peripheral control channel that is broadcast, and based on the measurement result. 2. The mobile communication system according to claim 1, wherein a list of control channels is created. 3. When a control channel having an electric field stronger than that of the control channel initially captured exists during the measurement of the electric field of the control channel in the peripheral zone, the control channel is re-captured, and the control channel is re-established from the control channel. 2. The mobile communication system according to claim 1, wherein information reading is performed again. 4. A mobile area in which a service area is constructed by a plurality of radio base stations, and one zone is provided with a control channel for performing call connection control for a mobile unit in the zone and a communication channel. In the body communication system, the server
If one of the zones Bisueria is congestion zone, within this <br/> congestion zone before the incoming call call mobile switching center sends, of the congestion zones for advance base station of the peripheral zone of the zone By instructing the measurement of the electric field of the uplink control channel, and measuring the electric field of the incoming call response transmitted to the uplink control channel of the mobile in response to the incoming call, the communication channel of the peripheral zone where the communication is possible is shifted.
A mobile communication system, wherein a mobile body is instructed to make a call within the congestion zone . 5. A mobile area in which a service area is constructed by a plurality of radio base stations, and one zone is provided with a control channel for performing call connection control for a mobile unit in the zone and a communication channel. In the body communication system, the server
If one zone of the service area is a congestion zone, the uplink electric field of the mobile unit that is talking in the congestion zone is measured by a base station in the surrounding zone, and after the call is terminated, the other station is transferred to another zone based on the measurement result. A mobile communication system characterized by instructing a shift of the mobile communication system. 6. A mobile area in which a service area is constructed by a plurality of radio base stations, and one zone is provided with a control channel for performing call connection control for a mobile unit in the zone and a communication channel. The mobile communication system has a data table for managing mobile units, and in the data table, a traffic level determined based on the number of outgoing / incoming calls per unit time, and each mobile unit performs outgoing / incoming calls last. Located in the congestion zone
From among the mobile units, select the
Register in advance from traffic level and last access time
A mobile communication system , wherein a specific mobile is extracted under specified conditions . 7. The extracted mobile unit is instructed to shift to a peripheral zone, and the mobile unit that has received the shift instruction switches to a control channel of a switchable peripheral zone. 7. The mobile communication system according to claim 6. 8. When a moving object during a call is extracted, an uplink electric field of the moving object is measured by a base station in a surrounding zone, and after a call is ended, transition to a surrounding zone is performed based on the measurement result. 7. The mobile communication system according to claim 6, wherein an instruction is given.