JP3208605B2 - Mobile communication system and radio base station - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system for allocating a radio channel to a mobile station such as a mobile phone or a mobile phone.
The present invention relates to a system and a radio base station . 2. Description of the Related Art In a mobile communication system including a radio base station and a mobile station such as a mobile phone or a mobile phone, a radio channel is assigned to the mobile station every time a call is generated. A call is made using a channel. In this case, since the number of wireless channels is finite, the wireless channels can be used effectively.
In order to be able, it is necessary to perform assignment of radio channels.

[0002]

2. Description of the Related Art As a radio channel allocation control system in a mobile communication system, for example, a fixed channel allocation system, a dynamic channel allocation system and the like are known. In the fixed channel assignment method, radio channels are arranged so as to reduce mutual interference corresponding to radio base stations, and each radio base station assigns a radio channel to a mobile station in its own zone. In addition, the dynamic channel assignment method, because the traffic fluctuates temporally and regionally,
The radio channels are rearranged in accordance with the fluctuation. In this case, there are a system for rearranging all the radio channels and a system for rearranging some radio channels.

The essence of this dynamic channel allocation method is to improve the time efficiency per channel, and to spatially efficiently arrange radio channels to increase the number of radio channels per unit area. Of the two. The temporal effect is, for example, a large-group effect obtained by setting all wireless channels common to all wireless base stations as search targets at the time of channel assignment. However, when the number of wireless channels to be relocated increases, the amount of relocation processing increases, and it becomes difficult to obtain an optimal relocation solution for minimizing the amount of interference. The spatial effect depends on how efficiently the radio channels are spatially packed. That is, it depends on whether the same wireless channel can be repeatedly allocated at short intervals.

As a means for improving the spatial effect, the following concept is known separately from the above-described dynamic channel allocation method. One is to increase the number of wireless channels per unit area by making the cell smaller. However, there is a limit in reducing the size of a cell, and a radio channel needs to be switched when a mobile station passes between cells. Since the switching of the radio channel occurs frequently, the processing load on the mobile communication system is reduced. growing.

As another one, for example, a reuse partitioning (hereinafter abbreviated as RUP) system is known. In the RUP method, a radio channel group is set according to the distance between the radio base station and the mobile station. For example, as shown in FIG. carrier power to interference power ratio (CIR) radio channel group F ₁ so increases, F _2, F ₃ are arranged, is at the communication between the mobile station 52 ₁ and the radio base station 51, desired mutual distance from the signal level is high is determined that the short, allocating assignable radio channel from the radio channel group F _1. The mobile station 52 ₂ and the radio base station 5
In communication with the wireless channel group F ₃ , it is determined that the distance between them is long because the desired signal level is small.
Allocatable wireless channels are assigned from

[0006] In this RUP system, a radio channel group F ₃ arranged in a zone far from the radio base station 51 has the same repetitive cell interval as in the fixed channel allocation system. radio channel group F ₁ which distance is arranged to close the zone, since interference from other wireless base station 51 decreases, it is possible to shorten the repeat cell interval. Therefore, it is possible to increase the number of radio channels that can be allocated per cell as an average of the entire system.

[0007]

SUMMARY OF THE INVENTION A mobile station in a mobile communication system communicates with a high-speed mobile station, such as a car phone, which talks while the car is running, while walking or stopping and talking. And mobile stations that move slowly. Also, a mobile phone is a mobile station that moves at a high speed when talking on a car or a train while riding, and a mobile station that moves at a low speed when talking on a car phone while the car is stopped. When such mobile stations having greatly different moving speeds coexist, the above-mentioned RU is used.
When the P method is applied, the following problem occurs.

[0008] In the RUP method shown in FIG. 5 described above, the radio channel is allocated from the radio channel group F ₃ to the mobile station 52 _2. If the mobile station 52 ₂ is slightly moved during the call as shown by a dotted line arrow, or when the moving distance is zero, need not switch the radio channel, at a relatively high speed during a call as shown by the solid line arrows When the mobile communication system moves, the mobile communication system passes through the assigned zone of the wireless channel groups F ₃ , F ₂ , F ₁ , F ₂ , and F ₃ , and the wireless channels are frequently switched. There is a disadvantage that the processing load increases. Alternatively, if the switching process cannot be performed in time, the call is continued using a wireless channel that causes large interference, and there is a disadvantage that the CIR deteriorates. An object of the present invention is to optimize the assignment of a radio channel in consideration of the moving speed of a mobile station.

[0009]

SUMMARY OF THE INVENTION A mobile communication system according to the present invention is provided.
Installations, substitute Referring to FIG. 1, divided a mobile communication system including a wireless base station 1 and mobile station 2, the radio channel to a plurality of radio channel group corresponding to the moving speed of the mobile station 2 and detects the moving speed of the mobile station 2 selects a radio channel group corresponding to the moving speed of the transfer <br/> Dokyoku 2,
From among the radio channel group and means for assigning a radio channel to the mobile station 2, no corresponding to the moving speed of the mobile station 2
Moving speed different from this moving speed when there is no line channel
Radio channels in the radio channel group corresponding to
Means for allocating files.

[0010] Also, the radio channel is set to correspond to the moving speed of the mobile station 2.
Divided into a plurality of radio channel groups corresponding to
The mobile station 2 detects the wireless communication speed corresponding to the moving speed of the mobile station 2.
Select a channel group and select
Means for allocating a radio channel to the mobile station 2;
No wireless channel corresponding to the moving speed of 2
Of the wireless channels corresponding to the moving speed different from the speed
When an assignable radio channel is assigned, the mobile station 2 moves
Allocatable wireless channels in the wireless channel group corresponding to the speed
As soon as a channel is created,
It has.

Also, the radio base station of the present invention provides a
Speed and distance from your own station
In the case of speed, it corresponds to the distance of this mobile station from its own station.
Allocate or move a wireless channel from a group of wireless channels
When the moving speed of the station is the maximum speed, the cell radius is the largest.
Radio that allocates a radio channel from a group of radio channels
A channel assignment control unit is provided.

[0012]

The mobile station 2 is divided into a plurality of radio channel groups corresponding to the moving speed of the mobile station 2. When the moving speed of the mobile station 2 is divided into, for example, a high speed and a low speed, the radio channel group F for the low speed movement is used. divided into ₁ and a radio channel group F ₂ for high-speed movement, is at 1, the wireless channel group F ₁ for slow-moving
Further shows a case of dividing disposed F ₁₁ to F ₁₃ corresponds to the distance from the radio base station 1, when the mobile station 2 moves at a high speed as indicated by a solid line arrow, by detecting the moving speed allocates assignable radio channel in the radio channel group F ₂ for high-speed movement. For the mobile station 2 moving at a low speed including a stop state as indicated by a dotted arrow, the radio base station 2
Corresponds to the distance or the like from allocating assignable radio channel in the radio channel group F ₁₁ to F _13. For example, allocating assignable radio channels in the mobile station 2 for the low-speed movement is assigned to a position to present wireless channel group F _13. Therefore, the wireless channel group for low-speed movement can increase the number of assignable wireless channels per cell. Further, the mobile station 2 moving at a high speed does not need to switch the radio channel in the same cell.

If there is no allocable radio channel in the radio channel group F ₂ for the high-speed mobile station 2 because there is no free radio channel in the radio channel group F ₂ , for example, allocating assignable radio channel in the radio channel group F ₁₃ for low speed movement. Further Conversely, by not idle wireless channel is present in the radio channel group F _13, the mobile station 2 of the slow moving, if assignable radio channel in the radio channel group F ₁₃ does not exist, for example, Wireless channel group F ₂ for high-speed movement
Are assigned to allocatable wireless channels. Therefore, the number of call losses can be reduced.

As described above, when there is no radio channel that can be assigned to a radio channel group corresponding to the moving speed and an allocatable radio channel of another radio channel group is assigned to the mobile station, When a vacant radio channel is generated in the set of radio channels, immediately by allocating a vacant radio channel to the mobile station, especially a high-speed mobile station, after switching to a high-speed mobile radio channel, Switching between radio channels is not required by movement within the cell.

[0015]

FIG. 2 is an explanatory view of an embodiment of the present invention.
Is a transmission / reception unit, 12 is a radio channel assignment control unit, 13 is a propagation loss detection unit, 14 is a moving speed detection unit, 15 is a radio channel state management unit, 16 is an assignment channel determination control unit, 17
Is an antenna, 20 is a mobile station, and 21 is an antenna.

The mobile communication system has a configuration including a radio base station and a mobile station 20. The plurality of radio base stations are connected to, for example, a higher-order mobile communication switching center. It is configured to be connected to a public network exchange. The transmitting / receiving unit 11 and the antenna 17 in FIG. 2 constitute at least a radio base station, and the radio channel assignment control unit 12 has a configuration arranged in the radio base station, or a mobile communication switching center or a higher order A configuration in which they are arranged in a central control station can be adopted. In addition, the propagation loss detecting unit 13, the moving speed detecting unit 14, the radio channel state managing unit 15, and the allocated channel determining control unit 16 are distributed and arranged in a radio base station, a mobile communication switching center, an upper centralized control station, and the like, respectively. Is also possible.

The radio channel group in the cell includes, for example, a radio channel group F ₂ for high-speed movement, as shown in FIG.
Divided into a radio channel group F ₁ for low speed movement, the radio channel group F ₁ for the slow moving further can be divided into groups F ₁₁ to F _13. Incidentally, it can be further divided into three groups F ₁ , F ₂ , F ₃ including a wireless channel group for medium-speed movement or more groups. Also, a wireless channel group F for low-speed movement
₁₁ to F _13, as shown in the case of arranging in the cell is divided into three, it is also possible to arrange the radio channel group is divided bisected or even a large number. When a wireless channel group for medium-speed movement is arranged, a wireless channel group F for low-speed movement is arranged.
It is also possible to divide and arrange the inside of the cell with a number smaller than the number of divisions in _one cell. Looking at all the low-speed moving channel groups, it can be seen that the number of radio channels that can be allocated in a cell can be increased as compared to the fixed channel allocation method, as in the above-described RUP method.

The propagation loss detecting unit 13 of the radio channel assignment control unit 12 detects the propagation loss between the radio base station and the mobile station 20 by detecting the level of the received signal received and processed by the transmitting and receiving unit 11 and the like. The propagation loss information is added to the assigned channel determination control unit 16. This propagation loss increases as the distance between the wireless base station and the mobile station 20 increases. Therefore, the current position (distance) of the mobile station 20 with respect to the wireless base station can be estimated.

The moving speed detector 14 detects the moving speed of the mobile station 20 based on the received signal.
Since fading occurs in accordance with the movement of the mobile station 20, the fading cycle becomes shorter in the case of a high-speed mobile station, and the fading cycle becomes longer in the case of a low-speed mobile station including a stopped state. , The moving speed of the mobile station 20 can be detected. Also, the moving speed of the mobile station 20 can be detected by detecting the Doppler frequency. Therefore,
The moving speed detecting unit 14 can be easily realized by a configuration having an arithmetic function such as a microprocessor. Further, as a received signal for detecting the moving speed, a control signal such as a wireless channel allocation request accompanying a call can be used. When the mobile station 20 has a function of transmitting the moving speed information, it is possible to easily determine whether the mobile station 20 is moving at a high speed or a low speed by using the moving speed information. No, therefore, as described above, the moving speed is detected by the radio base station or the mobile communication switching center.

When provided in a radio base station, the radio channel state management unit 15 manages the allocation state of radio channels in the cells of the radio base station. , Which manages the allocation status of the radio channels in the cell corresponding to each radio base station. The allocation channel determination control unit 16 transmits the radio channel allocation status information managed by the radio channel status management unit 15, The propagation loss information from the loss detector 13 and the moving speed detector 14
, A wireless channel group is determined on the basis of the moving speed information of the mobile station 20, and the presence or absence of an empty wireless channel in the wireless channel group is determined. The transmission / reception unit 11 notifies the mobile station 20 as a channel number.

FIG. 3 is a flow chart of one embodiment of the present invention, in which a mobile station is divided into a high-speed mobile station and a low-speed mobile station, and a radio channel is allocated. (A) As described above, the moving speed of the mobile station is detected by the moving speed detector 14 (b). The allocation channel determination control unit 16 determines the allocation of the wireless channel group according to the moving speed of the mobile station (c).

[0022] When the moving speed of the mobile station is high, allocates a radio channel group F _2, to assign channel selection in the radio channel group F ₂ (d). That is, the wireless channel group F
_The wireless channel status management unit 1 assigns the free wireless channel in
The search is performed based on the allocation state information of No. 5, and if there is no free wireless channel, it means that there is no wireless channel that can be allocated. If there are a plurality of available wireless channels, one of them is set and a wireless channel is assigned as an assigned wireless channel number (e). The allocated radio channel does not need to be switched even if the mobile station moves within one cell, and therefore, the processing load on the mobile communication system does not increase.

[0023] When the mobile station 20 is moving at low speed, it allocates a radio channel group F _1, allocates channel setting in the wireless channel group F ₁ (f). In that case, as shown in FIG. 1, the wireless channel groups F ₁₁ , F ₁₂ , F
₁₃ , the distance from the radio base station is determined based on the propagation loss information from the propagation loss detector 13. For example, if the propagation loss is large, a radio channel group F ₁₃ is assigned, searches the available radio channels in the state management unit 15 radio channel group F ₁₃ allocation status information based on from, if the available radio channel does not exist, a call loss (h). If there are multiple free wireless channels,
One of the wireless channels is set, and a wireless channel is assigned as an assigned wireless channel number (g). In this case, the mobile station moves at a low speed, but when the call moves to a zone of another wireless channel group for a long time, the mobile station is controlled to switch to a wireless channel in the wireless channel group.

FIG. 4 is a flow chart of another embodiment of the present invention, when the above-described embodiment is that clearly divide the radio channel group F ₁ of the radio channel group F ₂ and low-speed movement for high-speed movement In this embodiment, if there is no radio channel that can be allocated to one of the radio channel groups, it is determined whether there is a radio channel that can be allocated to the other radio channel group. If there is, the wireless channel is allocated, and the allocation of the wireless channel is made flexible.

The channel allocation request (1),
The steps of moving speed detection (2) and assignment channel group determination (3) are the same as in the above-described embodiment. When the moving speed of the mobile station is high, the process proceeds to step (4), assignable radio channel in the radio channel group F ₂ for high-speed movement is selected, the radio channel assignment is performed (5). Similarly, when the moving speed of the mobile station is low, the process proceeds to step (6), is selected the assignable radio channel in the radio channel group F ₁ for low speed movement, radio channel assignment is performed ( 7)

In the assignment channel selection (4) and (6), if there is no assignable radio channel, it is determined whether or not it is a priority group (8). Priority group is assigned channel group judgment
The wireless channel group determined in (3) is shown. If there is no assignable wireless channel and the wireless channel group is the priority group, another group search is performed (9). That, in the determination allocation channel group, assigned the radio channel group F ₂ for high-speed movement, if the assignable radio channel in the radio channel group F ₂ does not exist, the process proceeds to step (6) Te performs assignment channel selection for radio channel group F ₁ for low speed movement, also at the determined allocation channel group, assigned the radio channel group F ₁ for low speed movement, in that the radio channel group F ₁ If assignable radio channel does not exist, the processing proceeds to step (4), and performs allocation channel selection for radio channel group F ₂ for high-speed movement. In any case, if there is no radio channel to be allocated, in step (8), it is not a priority group, and in that case, a call is lost (10).

If there is a radio channel that can be allocated by another group search and the radio channel is allocated to a mobile station, if an allocatable radio channel occurs in a radio channel group that should be allocated, Since the allocation channel determination control unit 16 can make the determination based on the allocation state information of the wireless channel state management unit 15, it instructs the mobile station to switch to the wireless channel to be originally allocated. As a result, the wireless channel that has been accommodated from one wireless channel group to the other wireless channel group is returned, and the assignment of the wireless channel corresponding to the moving speed of the mobile station can be returned to the optimal state.

In the above-described embodiment, the inside of the cell is divided into three, and the low-speed moving radio channel group F ₁ is further divided and arranged into F _{11 to} F ₁₃ , and the high-speed moving radio channel group F ₂ is arranged. Shows a case where the radio channel group is arranged without dividing the cell, but the division and arrangement of the radio channel group can be variously changed without being limited to this embodiment. For example, the radio channel group for low-speed movement the radio channel group F ₁₁ to F ₁₃ in F ₁ as dynamic channel allocation scheme, it is also possible to rearrange dynamically.

[0029]

As described above, according to the present invention, a plurality of radio channel groups (for example,
For example , the mobile station 2 is divided into F ₁ , F ₂ ) , the moving speed of the mobile station 2 is detected, a radio channel group corresponding to the moving speed of the mobile station 2 is selected, and the radio channel group can be assigned from the radio channel group. The means for allocating the radio channel and the moving speed of the mobile station 2
When there is no corresponding radio channel,
Assignable radio channels from the set of allocated radio channels
For example, when the mobile station 2 includes a stopped state,
In the case of the lowest speed, as in the case of the RUP method,
Cell is divided into multiple cells according to the distance
By allocating radio channels from the line channel group
To shorten the repetitive cell interval of the same radio channel,
The number of assignable wireless channels can be increased. or
When the moving speed of the mobile station 2 is the highest speed,
Select an allocatable wireless channel from the
Select and assign the frequency of wireless channel switching.
Mobile communication system or radio base station.
There is an advantage that the processing burden can be reduced. Moving speed
Wireless channels that can be assigned to wireless channel groups corresponding to
If not, assign to other moving speed compatible wireless channels
If there is a possible radio channel, that radio channel
To reduce the probability of call loss
There are advantages that can be.

If there is no available wireless channel in the wireless channel group corresponding to the moving speed, and if there is an assignable wireless channel in another wireless channel group, the call channel is allocated by flexibly assigning the wireless channel. Loss can be reduced. Further, in this case, when an empty wireless channel is generated in the original wireless channel group, control is performed to switch from the wireless channel allocated and allocated to the original wireless channel, and the wireless channel group corresponding to the moving speed is changed. Can be used for communication.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of the present invention.

FIG. 3 is a flowchart of one embodiment of the present invention.

FIG. 4 is a flowchart of another embodiment of the present invention.

FIG. 5 is an explanatory diagram of the RUP method.

[Explanation of symbols]

 1 wireless base station 2 mobile station

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-234740 (JP, A) JP-A-4-65996 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 7/24-7/26 102 H04Q 7/00-7/38

Claims (3)

(57) [Claims] We claim: 1. In a mobile communication system including a radio base station and the mobile station divides a radio channel to a plurality of radio channel group corresponding to the moving speed of the mobile station, a moving speed of the mobile station Means for detecting and selecting a radio channel group corresponding to the moving speed of the mobile station , and allocating a radio channel to the mobile station from the radio channel group; and a radio channel corresponding to the moving speed of the mobile station. When not
Wireless channel corresponding to a moving speed different from the moving speed.
And means for assigning the assignable radio channels in the Le group
A mobile communication system comprising: 2. Mobile communication including a radio base station and a mobile station.
In the system, a plurality of wireless channels corresponding to the moving speed of the mobile station are set.
Divide into wireless channels and detect the moving speed of the mobile station
And a radio channel group corresponding to the moving speed of the mobile station
Radio station to the mobile station from the radio channel group.
Means for allocating a channel, and no wireless channel corresponding to the moving speed of the mobile station,
Wireless channel group corresponding to a moving speed different from the moving speed
When an allocatable wireless channel in
Assignable within the wireless channel group corresponding to the moving speed of the station
Switch to this radio channel as soon as it is generated
Mobile communication system characterized by having means. 3. The moving speed of the mobile station and the distance from the own station are determined.
If the moving speed is the lowest speed,
Among the radio channels corresponding to the distance of the mobile station
Radio channel, and the moving speed of the mobile station is the highest.
In the case of speed, the wireless channel group with the largest cell radius
Radio channel allocation control unit that allocates radio channels from inside
Radio base station, comprising the.