JP3163527B2 - Location registration method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a location registration method for mobile communication.

[0002]

2. Description of the Related Art Numerous systems have been proposed as conventional location registration control methods in mobile communication. For example, JP
3-131131 (Japanese Patent Application No. 01-268273). This is because the mobile station collects the history of the radio cells in the area, performs statistical processing on the history, and stores an individual location registration area composed of radio cells having a high probability that the mobile station is in the area.
131131 is a method for setting a high-probability area. Hereinafter, this position registration method will be described with reference to the drawings.

FIG. 1 shows a configuration example of a location registration area in the above-mentioned conventional method. M1 is a mobile station, A1 to A8 are radio cells, and B1 to B8 are radio base stations corresponding to the radio cells. PA1 is an individual location registration area of the mobile station M1,
The mobile station M1 is composed of a predetermined number of wireless cells having a high probability of being located. The individual location registration area PA1 can be used only by the mobile station M1, and other mobile stations cannot be used as the location registration area. On the other hand, SA1 and SA2 are common location registration areas. This is available for all mobile stations. When the mobile station M1 is located in the individual location registration area PA1, the mobile station M1 sets the individual location registration area PA1 as the located location registration area.
Is registered, and when the mobile phone exits from the individual location registration area PA1, the location registration is performed for the common location registration area in which the user is located.

The operation of the location registration will be described with reference to FIG. Hereinafter, a location registration area registered as a location registration area in which the area is located will be referred to as a registration area.

[0005] For example, it is assumed that a mobile station M1 located in the radio cell A1 and having the individual location registration area PA1 as a registration area has moved to the radio cell A2. The mobile station M1 has a registration area P
Location registration is not performed because the user is located in A1. Next, it is assumed that the mobile station M1 has moved to the wireless cell A7 via the wireless cell A6. Also in this case, since the mobile station M1 remains in the registration area PA1, the location registration is not performed. Thereafter, assuming that the mobile station M1 has moved to the radio cell A8,
Is outside the area of the registration area PA1, the mobile station M1 performs location registration. When the mobile station leaves the individual location registration area, the location registration of the common location registration area where the mobile station is located is performed. In this example, the common location registration area SA2 is registered.
Thereafter, it is assumed that the mobile station M1 has returned to the wireless cell A7. At this time, since the mobile station M1 is again located in the individual location registration area PA1, the mobile station M1 registers the location of the individual location registration area PA1.

When the above-described method is used, the mobile station is located in the individual location registration area with a high probability, and the probability that the mobile station enters and exits the individual location registration area and performs location registration is reduced.
For this reason, location registration traffic is reduced.

[0007]

However, in one day,
The time period during which movement (= location registration) peaks and the time period during which calls (incoming call traffic and call traffic) peak generally differ, and a separate means for efficiently accommodating each peak in the system is required. Becomes

It is an object of the present invention to efficiently accommodate location registration signal traffic and incoming call traffic, which typically peak at different times of day, in a system.

[0009]

A feature of the present invention resides in that a location registration area is adaptively set according to a ratio of location registration signal traffic to incoming call traffic or call traffic.

The prior art focuses on the difference between the time zones of the peaks of the location registration traffic and the call traffic. The location registration area is wide at the peak of the location registration traffic, and the location registration traffic is narrow at the peak of the call traffic. And the purpose is to efficiently accommodate the two traffic peaks in the system.

[0011]

【Example】

(Embodiment 1) FIG. 2 is a configuration diagram of a radio cell / location registration area of a mobile communication system embodying the present invention. Each wireless base station will be described as having an incoming call control channel and a location registration channel, but these may use other control channels and communication channels.

According to the flowchart shown in FIG. 3, the central control station 2-a assigns a location registration code to each radio cell (2-b, 2-c), and each radio station is assigned by a broadcast channel. The position registration code is transmitted as a position registration area change signal in the format shown in FIG.

The mobile station (2-d) under the control of the radio cell rewrites the location registration code in the memory in accordance with the transmitted location registration area change signal.

In normal times (when the location registration area setting is not changed), each radio base station periodically transmits a location registration code on the broadcast channel in the format shown in FIG. The mobile station transmits a position registration request signal to the radio base station only when the value of the position registration code in the memory differs from the value of the received position registration code.
As described above, the present system operates so that the consistency of the location registration control is not lost by the location registration change.

Next, a description will be given of the algorithm for changing the setting of the location registration area shown in FIG.

The present algorithm starts from the state of wireless cell = location registration area (FIG. 6) and adjusts the size of the location registration area adaptively.

The central control station operates each location registration area (1 <i
For <n), the number of incoming call channels in the location registration area (depending on the number of cells in the location registration area) = A _{i The} number of channels for location registration request signals in the location registration area (depending on the number of cells in the location registration area) ) = B _i Calling traffic in the location registration area = C _i Location registration request traffic in the location registration area = D _i , incoming call loss rate for each location registration area = E _i Location registration request signal loss rate for each location registration area = F _i Is calculated (10).

For a location registration area i, E _i <F
_{If i} (12), the adjacent location registration area (1 <
j <n), the area j in which the value of E _j / F _j is 1 or less and the smallest is selected, and the incoming call loss rate E and the position registration request signal loss rate of the virtual location registration area when both are merged. F is the number of incoming call channels in the location registration area (depending on the number of cells in the location registration area) = A _i + A _{j the} number of channels for the location registration request signal in the location registration area (dependent on the number of cells in the location registration area) = B _i + B _j Call traffic in location registration area = C _i + C _j Location registration request traffic in location registration area = D ′ (≦ D
_i + D _j ), F becomes small because D ′ becomes small, and E /
F is larger than E _i / F _i or E _j / F _j , but E / F
(16) (FIG. 7. The state before the merge is stored in the memory of the central control station. It is only necessary to manage the correspondence table between each cell and the position registration code. ). FIG. 8 shows the memory format.

If E _i > F _i and the location registration area is formed by a plurality of cells,
If necessary, return the location registration area to the state before fusion (that is,
The process is repeated until there are no more combinations of location registration areas that can be merged.

The conditions for merging (separating) location registration areas are as follows:
E _i / F _i > α (constant value).

Second Embodiment In the description of the first embodiment, the location registration area forming algorithm shown in FIG.
Instead of the call loss rate of the incoming call signal, the number of communication channels in the location registration area (depending on the number of cells in the location registration area) = G _i The communication traffic in the location registration area = _Hi is calculated in the location registration area. configured to operate based on the call loss probability = I _i are also possible. I _i is the loss rate for both outgoing and incoming calls.

Further, the condition for merging (separating) the location registration areas may be set to E _i / I _i > α (constant value).

(Embodiment 3) FIG.
The algorithm for forming the location registration area shown in the above is periodically applied to the number of incoming call channels in the wireless cell of the wireless cell i (1 <i <n) = a _{i The} number of channels for the location registration request signal in the wireless cell = b from _i radio cell call traffic = c _i radio cell location registration request traffic = d _i, incoming call blocking probability = e _i obtain the position registration request signal blocking probability = f _i for each radio cell (20) for each radio cell, adjacent E _j / f from all the radio cells
_It is changed that the location registration area is formed around the wireless cell (9-a in FIG. 9) having a small value of _j .

"E _j / f _j from all adjacent radio cells
Is small (22), and among the wireless cells (1 <j <n) adjacent to the location registration area to be newly formed, e is selected.
_The number of incoming call channels in the location registration area after absorption (in the number of cells in the location registration area in the location registration area after absorption) in the order of smaller values of e _j / f _j in the radio cells having a value of _j / f _j of 1 or less. dependent) = a _'k location registration area location registration request signal for the channel number (depending on the number of the cell location registration area) = B' _k location registration area call traffic = C _'k location registration area location registration request traffic = D _'k is calculated from the estimated incoming call loss probability = E for each location area' _k location registration each area estimated position registration request signal blocking probability = F '
_{As long as k} is E ′ _k <F ′ _k , absorption is performed (9-
2) (24).

When the absorption becomes impossible, another radio cell which satisfies the condition "the value of e _j / f _j is smaller than all adjacent radio cells" is selected and the above processing is performed.

From all adjacent radio cells e _j
When the above processing is performed for the wireless cell having a small value of / f _j , the process is terminated (28). FIG. 10 shows a flowchart.

The conditions for merging the location registration areas are E ' _i /
F _i > α and e _i / f _i > α (constant value).

(Embodiment 4) In Embodiment 3 described above, instead of the terminating call loss rate for each radio cell = e _i , the terminating call loss rate for each location registration area = E _i , the call loss rate in the radio cell = _ii location registration merger conditions call loss probability = I _i location registration area in the _{area, E 'i / F' i} > α and e _i / f _i> α may be (a constant value).

[0029]

The present invention focuses on the fact that the incoming (call) traffic and the movement (= position registration signal) generally peak in different time zones.

If the incoming (call) traffic is relatively small during the peak period of the movement, the location registration area is expanded to suppress the traffic of the location registration request signal and to receive the call, Only when necessary (mainly when the power is turned on), the location registration request signal can be transmitted.

In the method of performing a paging call in the location registration area at the time of an incoming call, if the location registration area is widened, the incoming traffic increases. However, if the incoming traffic is relatively small, it can be accommodated without any problem.

Conversely, in the time zone when the incoming traffic is at its peak, by setting the location registration area narrow, incoming call traffic can be suppressed and accommodated, and the location registration request traffic increases. However, if the location registration request traffic is relatively small, there is no problem in accommodation.

As an example, the capacity of the channel for the location registration request signal and the capacity of the channel for the paging signal are T erlangs in each cell, and the number of location registration requests per one hour per subscription at the peak of the location registration request signal traffic. To y
Times, the number of incoming call signals is z times, the number of location registration requests per one hour per subscription at the peak of incoming call traffic is u times,
Let the number of incoming call signals be v.

The time during which the control channel is occupied by one location registration and one incoming call is assumed to be w seconds.

Hereinafter, it is assumed that max (a, b) represents the larger value of a and b.

Assuming that the position registration area is composed of 10 cells in the conventional method of fixing the position registration area, when the position registration request traffic peaks, 10 × T ÷
At the peak of (y × w / 3600) subscription and incoming request traffic, only T ÷ (10 × v × w / 3600) subscription can be accommodated (per cell). One location registration area during peak hours
Assuming that the location registration area is composed of 00 cells and 1 cell at the peak of incoming call traffic, 100 × T ÷ (y × w / 3) at the peak of location registration request traffic.
600) T ÷ at the peak of subscription and incoming request traffic
(V × w / 3600) subscriptions can be accommodated. (10 each
Doubled)

According to the present invention, incoming call traffic and location registration traffic can be efficiently accommodated in the system as described above.

[Brief description of the drawings]

FIG. 1 is a configuration example of a location registration area in a conventional method.

FIG. 2 is a configuration example of a wireless cell / location registration area according to the first embodiment of the present invention.

FIG. 3 is a flowchart of a location registration area forming algorithm according to the first embodiment.

FIG. 4 is a format diagram of a position registration code change signal.

FIG. 5 is a format diagram of a position registration code notification signal.

FIG. 6 is an initial state diagram when the first embodiment is performed.

FIG. 7 is a diagram in which the wireless cell is merged into the location registration area according to the first embodiment.

FIG. 8 is a format diagram of a location registration code management table in the central control station.

FIG. 9 is a diagram in which a wireless cell is merged into a location registration area according to the third embodiment.

FIG. 10 is a flowchart of a location registration area forming algorithm according to the third embodiment.

[Explanation of symbols]

 A1 to A8 Wireless cell B1 to B8 Wireless base station M1, M2 Mobile station SA1, SA2 Common location registration area PA1, PA2 Individual location registration area

Claims (4)

(57) [Claims] 1. A wireless communication system comprising: a plurality of radio base stations and a plurality of mobile stations, wherein a radio cell is allocated to each of the base stations, a location registration area in which a plurality of the radio cells are combined is defined, The station registers the location registration area in which the station is currently located, and when an incoming call to the mobile station occurs, the location of the mobile station is determined within the radio cell configuring the location registration area registered. In a location registration control method of mobile communication for performing an incoming call, a first call blocking rate is calculated from an incoming call traffic in the location registration area and the number of channels for an incoming call, and a location registration request traffic and a location in the location registration area are calculated. Calculating a second loss probability from the number of registration request signal channels, and configuring the location registration area according to whether the ratio between the first loss probability and the second loss probability is greater or less than a predetermined value. A location registration method characterized by changing the location. 2. A configuration change of a location registration area is performed by merging / separation of adjacent location registration areas, and a ratio of the first blocking loss rate and the second blocking loss rate of the location registration area is less than one. When there is a certain location registration area, the location registration area to be merged has a ratio of the first blocking loss rate and the second blocking loss rate of each location registration area of 1 or less from a plurality of adjacent location registration areas. And the location registration area having the smallest value is selected, and when the ratio between the first loss probability and the second loss probability when it is assumed that the selected location registration areas are merged is less than one, The location registration method according to claim 1, wherein the location registration method is performed. 3. The change of the configuration of the location registration area is performed by merging / separation of adjacent radio cells, and a ratio of the first blocking loss rate and the second blocking loss rate of the location registration area is smaller than 1. In this case, it is determined that the radio cells are to be merged, and the ratio of the first loss probability and the second loss probability for each radio cell is 1 or less and the most Selecting a radio cell with a smaller value, and actually merging when the ratio between the first loss probability and the second loss probability when the selected radio cells are merged is smaller than 1. The location registration method according to claim 1, wherein 4. The location registration method according to claim 2, wherein said first call loss rate is calculated from outgoing / incoming call traffic and a call channel.