JP4009516B2 - Mobile communication system, mobile communication method, and control station - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cellular mobile communication system, a mobile communication method, a control station, and a base station in which a base station (BS) to which directional beam transmission / reception is applied and a base station to which directional beam transmission / reception is not applied are mixed. And the mobile station.
[0002]
[Prior art]
Conventionally, in a mobile communication system, a cellular system that covers a service area by arranging a plurality of base stations in a cell shape is applied. In this cellular system, a sector cell configuration is used in which one cell is further divided into a plurality of sectors and a base station antenna is installed in each sector to form a service area. In current mobile communication services, a three-sector or six-sector configuration is generally applied as shown in FIGS.
[0003]
In the conventional mobile communication system as described above, as a technique for suppressing interference power from other users, there is a directional beam transmission / reception technique using an adaptive antenna array. This uses a plurality of antennas to transmit / receive, assigns an appropriate weight to each antenna's input signal, and synthesizes according to this weight, using an independent directional beam for each user. Directional transmission / reception is performed to reduce interference power from other users.
[0004]
For example, the document “Pilot symbol-assisted decision-directed coherent adaptive array diversity for DS-CDMA mobile radio reverse link,” (S. Tanaka, M. Sawahashi, and F. Adachi: IEICE Trans. Fundamentals, vol. E80-A, pp. 2445-2454, Dec. 1997.) Proposed coherent adaptive antenna array (CAAAD) reception method using pilot symbols in DS-CDMA (Direct Sequence Code Division Multiple Access) radio access system Has been.
[0005]
Also, instead of generating an antenna weight for each user and performing beam forming, reception is performed using a plurality of beams of a fixed antenna weight defined in advance, and the received signal power of each beam is measured to maximize the received signal power. There is also a multi-beam transmission / reception system in which transmission / reception is performed using a beam antenna weight.
[0006]
Multi-beam reception can reduce the amount of signal processing for generating antenna weights compared to the case of generating antenna weights for each user and receiving directivity, but especially when the user is located at the boundary between two beams. In this case, the beam directivity error becomes large, and the interference reduction effect becomes small.
[0007]
Also, reference "Comparison of Adaptive Antenna Array Diversity Reception and Multi-beam Reception in W-CDMA Uplink," (Nanami, Tanaka, Ihara, Sawahashi: IEICE Technical Report, RCS2000-132, pp.29-36, Oct. .2000.), When receiving a random access signal such as RACH, the signal length of the random access signal is relatively short. Therefore, the directional beam reception that generates the antenna weight for each user described above is sufficient. As a result, it has been reported that multi-beam reception is more suitable.
[0008]
Also in the downlink, the document "Adaptive antenna array transmit diversity in FDD forward link for WCDMA and broadband packet wireless access," (H.Taoka, S. Tanaka, T.Ihara, and M.Sawahashi; IEEE Wireless Communications, pp. 2-10, April 2002), there is an adaptive antenna array transmission method that performs directional beam transmission after compensating for amplitude and phase fluctuations generated in a radio circuit for a beam pattern formed in the uplink. By applying directional beam transmission in the downlink, it is possible to reduce other user interference power in the same sector and other user interference power from other cells and other sectors, and thus increase communication capacity.
[0009]
The channel configuration in the downlink is roughly divided into an individual channel for transmitting individual information data of each user and a common channel for transmitting control data common to all users. FIGS. 10A and 10B show examples of transmission beam patterns of the dedicated channel and the common channel in the downlink in the base station BS to which directional beam transmission / reception by the adaptive antenna array is applied.
[0010]
As shown in FIG. 5A, by transmitting the individual channel of each user through beam patterns BP1 and BP2 in which the beam is narrowed by directional beam transmission, the interference power between users can be reduced. On the other hand, the common channel for transmitting control information is transmitted by an omnidirectional beam so that all users in the sector can receive it, as shown in FIG.
[0011]
[Non-Patent Document 1]
S. Tanaka, M. Sawahashi, and F. Adachi: IEICE Trans. Fundamentals, vol. E80-A, pp. 2445-2454, Dec. 1997.
[0012]
[Non-Patent Document 2]
Nakanami, Tanaka, Ihara, Sawahashi: IEICE Technical Report, RCS2000-132, pp.29-36, Oct.2000.
[0013]
[Non-Patent Document 3]
H. Taoka, S. Tanaka, T. Ihara, and M. Sawahashi; IEEE Wireless Communications, pp. 2-10, April 2002.
[0014]
[Problems to be solved by the invention]
However, in the conventional base station transmission method, as shown in FIG. 11, when a base station BS1 to which directional beam transmission / reception is applied is adjacent to a base station BS2 to which directional beam transmission / reception is not applied, a common channel is set. Transmission was performed with the same transmission power, and the areas of the service areas A1 and A2 of each BS were approximately the same.
[0015]
Here, as a method of transmitting and receiving a directional beam, for example, the antenna weight is adaptively controlled for each user by adaptive antenna array reception in the uplink to receive the directional beam, and the uplink antenna weight is used in the downlink. Adaptive antenna array transmission / reception method for transmitting directional beams, or receiving in advance using a plurality of directional beams with fixed antenna weights in the uplink, selecting the beam with the highest received signal power, and receiving the directional beam. In the link, a multi-beam transmission / reception method in which a directional beam is transmitted using a beam selected in uplink reception is used.
[0016]
In this case, in the service area A1 of the base station BS1 to which the directional beam transmission / reception is applied, the communication capacity can be increased by the interference suppression effect by the beam forming, but the service of the base station BS2 to which the directional beam transmission / reception is not applied. In the area A2, the communication capacity does not increase.
[0017]
Here, for example, consider a case where a new user transmits in the base station BS2 area when the communication traffic increases and the traffic amount of the base station BS2 reaches the capacity limit. In this case, even when the traffic volume of the base station BS1 does not reach the capacity limit, the base station BS2 cannot connect to a new user.
[0018]
Therefore, in the conventional base station transmission method, there is a bias in the user distribution for each area, the demand for communication traffic of the base station BS1 to which directional beam transmission / reception is applied is small, and the base station BS2 to which directional beam transmission / reception is not applied. When the demand for communication traffic is large, there is a problem that the communication traffic in the base station BS2 to which directional beam transmission / reception is not applied is limited due to the limitation of the communication capacity.
[0019]
The present invention solves the above problems, and a mobile communication system capable of efficiently connecting a user in both a base station to which directional beam transmission / reception is applied and a base station to which directional beam transmission / reception is not applied, The object is to provide a mobile communication method, a control station, a base station, and a mobile station.
[0020]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is directed to performing mobile communication in an area where a first base station to which directional beam transmission / reception is applied and a second base station to which directional beam transmission / reception is not applied are adjacent to each other. In addition, by expanding the service area of the first base station or reducing the service area of the second base station, the service area of the first base station is made wider than the service area of the second base station. Set.
[0021]
In the above invention, in the directional beam transmission / reception, a directional beam pattern unique to each mobile station is generated based on a weight given to each mobile station, and a signal is transmitted / received via the directional beam pattern. It is preferable to use an adaptive antenna array.
[0022]
In the above invention, the service area of the first base station is expanded by expanding the service area of the first base station or reducing the service area of the second base station. It is preferable to overlap the original area.
[0023]
ADVANTAGE OF THE INVENTION According to this invention, a part of user in the area of the base station which does not apply directional beam transmission / reception can be distributed and connected to the base station to which directional beam transmission / reception is applied, and directional beam transmission / reception is applied. Therefore, it is possible to efficiently connect users in both the base station that performs this and the base station that does not apply directional beam transmission / reception.
[0024]
In the above invention, the transmission power of the downlink common channel transmitted by each base station is controlled according to the area set by the area setting means, and the reception quality based on the controlled transmission power of the downlink common channel is controlled on the mobile station side. It is preferable to select an area to be connected according to the above. In this case, by changing the transmission power in the downlink, the base station to which the mobile station is connected can be controlled on the base station or control station side, and the setting of the service area described above can be controlled by the base station or control. It can be managed on the station side.
[0025]
In the above invention, the report value of the transmission power of the downlink common channel to be notified to each mobile station is controlled, and the mobile station receives the downlink common channel reception quality value from each base station and the notified downlink common channel transmission. It is preferable to calculate a propagation loss based on the reported power value and select an area to be connected according to the calculated propagation loss. In this case, the base station to which the mobile station is connected can be controlled on the base station or control station side by changing the report value in the downlink, and the setting of the service area described above can be controlled by the base station or the control station. It can be managed on the station side.
[0026]
In the above invention, when setting the service area, it is preferable to control the transmission power of the downlink common channel based on the traffic amount in each base station and the type of each base station. In this case, the service area can be set in consideration of communication load such as the traffic amount of each base station and information such as whether or not directional beam transmission / reception is applied.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a mobile communication system according to an embodiment of the present invention.
[0028]
As shown in the figure, the mobile communication system according to the present embodiment is based on, for example, a DS-CDMA mobile communication system, and includes mobile stations MS1 to 6, base stations BS1 to BS4, and mobile stations MS1 to MS6. And a radio network controller (RNC) 1 that controls the entire mobile communication system, such as connection control of radio links between the base stations BS1 to BS4.
[0029]
The wireless network control device 1 is a device that manages and controls communication processing of each of the base stations BS1 to BS4, and is connected to the plurality of base stations BS1 to BS4 through a wired transmission path. Specifically, as shown in FIG. 2, the wireless network control device 1 includes area setting means and a transmission power notification unit 14.
[0030]
The area setting means expands the service area A1 of the base station BS1 to which directional beam transmission / reception is applied, or reduces the service area A2 of the base station BS2 to which directional beam transmission / reception is not applied, thereby This module sets the service area A1 wider than the service area A2 of the base station BS2. In this embodiment, the common channel transmission power determination unit 11, the traffic amount measurement unit 13, and the base station (BS) information storage unit 12 It consists of.
[0031]
The base station information storage unit 12 is a database that stores information related to the communication method of each of the base stations BS1 to BS4. For example, each base station applies or does not apply directional beam transmission / reception. The BS type information for identifying the information is held. The base station information storage unit 12 reads information of each base station in response to a request from the common channel transmission power determination unit 11.
[0032]
The traffic volume measuring unit 13 is a module that measures the traffic volume in each of the base stations BS1 to BS4. In this embodiment, the traffic volume measuring unit 13 outputs the traffic volume of each base station in response to a request from the common channel transmission power determining unit 11. .
[0033]
The common channel transmission power determination unit 11 is a module that determines the transmission power of the downlink common channel transmitted by each of the base stations BS1 to BS4. In the present embodiment, the common channel transmission power determining unit 11 is a BS related to the traffic volume in each of the base stations BS1 to BS4 measured by the traffic volume measuring unit 13 and the type of each base station stored in the base station information storage unit 12. The transmission power of the downlink common channel is set based on the information.
[0034]
The transmission power notification unit 14 is a communication device that notifies the transmission power determined by the common channel transmission power determination unit 11 to the transmission power change unit 21 of the corresponding base stations BS1 to BS4. In the present embodiment, the transmission power notifying unit 14 and the transmission power changing unit 21 of the wireless network control device 1 constitute transmission power control means.
[0035]
The plurality of base stations BS1 to BS4 are relay base stations that form a service area by a cellular configuration, and in the present embodiment, each mobile station MS1 is based on a weight assigned to each mobile station MS1 to MS6. A directional beam pattern unique to the MS 6 is generated, and an adaptive antenna array 22 that transmits and receives signals through the directional beam pattern is provided.
[0036]
Each of the base stations BS1 to BS4 includes a transmission power changing unit 21 that changes the transmission power of the downlink common channel based on the transmission power notification notified from the transmission power notification unit 14 of the radio network control device 1. . The transmission power changing unit 21 adjusts the transmission power of the adaptive antenna array 22.
[0037]
Further, the mobile stations MS1 to MS6 each have a receiving unit 33 that receives the transmission power of the downlink common channel controlled so that the service area A1 of the base station BS1 is wider than the service area A2 of the base station BS2, and the received downlink A reception quality calculation unit 31 that calculates reception quality based on the transmission power of the common channel and an area selection unit 32 that selects an area to be connected according to the calculated reception quality are provided.
[0038]
(Service area setting)
FIG. 3 is an explanatory diagram showing an example of the configuration of the service area according to the present embodiment. In the present embodiment, a case where area determination is performed based on the reception quality value of the downlink common channel in the mobile stations MS1 to MS6 will be described as an example.
[0039]
In the present embodiment, the service area A1 of the base station BS1 is reduced by expanding the service area A1 of the base station BS1 or reducing the service area A2 of the base station BS2 by the area setting means of the control station. It is superimposed on the original service area A2 ′.
[0040]
More specifically, in this embodiment, by increasing the transmission power of the P-CPICH of the base station BS1, the reception quality value (RSCP or Ec) of the common channel calculated by the reception quality calculation unit 31 of the mobile stations MS1 to MS6. / NO) is increased to expand the service area. Further, by reducing the transmission power of the P-CPICH of the base station BS2, the reception quality value (RSCP or Ec / NO) of the common channel calculated by the reception quality calculation unit 31 of the mobile stations MS1 to MS6 is reduced, thereby reducing the service area. Is shrinking.
[0041]
As a result, the base station BS1 can cover a part of the service area of the base station BS2. In this case, a part of the traffic in the service area of the original base station BS2 can be accommodated by the base station BS1 having a large communication capacity.
[0042]
Thus, for new users occurring in the service area of the original base station BS2, for the users in the new service area of the base station BS1, the base station BS1 and for users in the new service area of the base station BS2 It can be accommodated by BS2.
[0043]
As the reception quality value of the downlink common channel in each service area, for example, the received signal power RSCP (Received Signal Code Power) of P-CPICH (Primary Common PLlot Channel) can be used, or Ec / NO (1 The received signal power to noise power density ratio per chip) can also be used. In the W-CDMA system, area determination based on Ec / NO of P-CPICH can be used as an area determination method when waiting for communication.
[0044]
(Mobile communication method using mobile communication system)
Next, a mobile communication method using the above-described mobile communication system will be described. FIG. 4 is a diagram illustrating an example of a flowchart of cell area selection in the present embodiment.
[0045]
First, the traffic volume measuring unit 13 of the radio network controller 1 measures the traffic volume in each of the base stations BS1 to BS4 (S101). Then, based on the BS information of each of the base stations BS1 to BS4 held in the base station information storage unit 12 and the measurement value of the traffic amount measurement unit 13, the common channel transmission power determination unit 11 of the radio network controller 1 The transmission power of the P-CPICH of the station BS is determined (S102).
[0046]
The wireless network control device 1 notifies the base station BS1 to BS4 of information on the transmission power value of the P-CPICH through the transmission power notification unit 14 (S103), and the base station BS transmits the transmission power notification unit 14 to the base station BS. Thus, based on the notified value, the P-CPICH is transmitted through the adaptive antenna array 22 (S104).
[0047]
In the mobile stations MS1 to MS6, the reception quality calculation unit 31 calculates the reception quality value (RSCP or Ec / NO) of the P-CPICH of each base station BS, and selects an area based on the calculated reception quality value. The unit 32 performs cell area selection (S106).
[0048]
(Action / Effect)
As described above, the service area is controlled by adaptively changing the transmission power of the P-CPICH of each base station BS according to the traffic volume that changes with time, so that even when the traffic distribution fluctuates, it is efficient. Can accommodate users, and part of the benefit of increased capacity by applying directional beam transmission / reception can be distributed to neighboring base stations BS that do not apply directional beam transmission / reception. It becomes possible to accommodate users efficiently in the station BS.
[0049]
(Example of change)
In the present embodiment, the wireless network control device 1 measures the traffic volume in each of the base stations BS1 to BS4, and transmits the P-CPICH based on the base station type information of each of the base stations BS1 to BS4 and the traffic measurement result. Although the power is adaptively controlled at a fixed period, the setting of the transmission power of the P-CPICH is fixedly set to a value determined in advance by the type information of each base station BS1 to BS4 (for example, directional beam transmission / reception is performed). For the base station BS1 to be applied, the downlink common channel transmission power may be set to a value larger by X dB).
[0050]
[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, area determination is performed based on the propagation loss value obtained from the difference between the common channel reception quality value from each base station BS in the mobile station and the report value of the common channel transmission power broadcast by broadcast information.
[0051]
(Configuration of mobile communication system)
Similarly to the first embodiment described above, the mobile communication system according to the second embodiment also includes mobile stations MS1 to 6, base stations BS1 to 4, and radio stations between the mobile stations MS1 to MS6 and the base stations BS1 to BS4. A radio network controller (RNC: Radio Network Controller) 1 that controls the entire mobile communication system, such as link connection control, is provided.
[0052]
In the present embodiment, the wireless network control device 1 includes area setting means and a report value notification unit 43 as shown in FIG. In this embodiment, the area setting unit includes a report value determination unit 41, a traffic amount measurement unit 13, and a base station (BS) information storage unit 12.
[0053]
The base station information storage unit 12 is a database that stores information related to the communication method of each of the base stations BS1 to BS4. For example, each base station applies or does not apply directional beam transmission / reception. The BS type information for identifying the information is held. The traffic amount measuring unit 13 is a module that measures the traffic amount in each of the base stations BS1 to BS4.
[0054]
The report value determining unit 41 is a module that determines a report value of the transmission power of the downlink common channel to be notified to the mobile stations MS1 to MS6. In this embodiment, each base station BS1 measured by the traffic amount measuring unit 13 is used. Based on the traffic amount in BS4 and the BS information related to the type of each base station stored in the base station information storage unit 12, the report value of the transmission power of the downlink common channel is determined. Note that the report value in this embodiment is determined according to the offset processing by the offset unit 42. This offset processing will be described later.
[0055]
The report value notification unit 43 is a communication unit that notifies the mobile station MS1 to MS6 of the report value determined by the report value determination unit 41 via the notification unit 51 of the corresponding base station.
[0056]
The plurality of base stations BS1 to BS4 are relay base stations that form a service area by a cellular configuration, and in the present embodiment, each mobile station MS1 is based on a weight assigned to each mobile station MS1 to MS6. A directional beam pattern unique to the MS 6 is generated, and an adaptive antenna array 22 that transmits and receives signals through the directional beam pattern is provided. In the present embodiment, the transmission power of the adaptive antenna array 22 is a fixed value notified from the wireless network control device 1.
[0057]
Each base station BS1 to BS4 includes a notification unit 51 that notifies the mobile stations MS1 to MS6 of the report value notified from the transmission power notification unit 14 of the radio network control device 1.
[0058]
Further, the mobile stations MS1 to MS6 were notified of the notification information from the notification unit 51, the reception unit 33 that receives signals from the adaptive antenna array 22, and the reception quality value of the downlink common channel from each base station. Based on the report value of the downlink common channel transmission power, a propagation loss calculation unit 61 that calculates a propagation loss and an area selection unit 62 that selects an area to be connected according to the calculated propagation loss are provided.
[0059]
(Service area configuration)
FIG. 7 is an explanatory diagram showing an example of a service area configuration according to the present embodiment. In the present embodiment, by controlling the report value transmitted to each base station, the service area A1 of the base station BS1 is expanded, or the service area A2 of the base station BS2 is contracted, whereby the service of the base station BS1 The area A1 is superimposed on the original service area A2 ′ of the base station BS2.
[0060]
More specifically, in the W-CDMA system, area determination using a propagation loss is used as an area determination method for handover during communication. In mobile communication, the received power of a radio signal transmitted from a base station at the mobile station decreases as the distance from the base station increases due to a propagation loss. Therefore, the mobile station connects to the base station with the best propagation environment by selecting a base station with a small propagation loss. As an example, the received signal quality is measured using P-CPICH as a downlink common channel, and the report value of the P-CPICH transmission power in each base station is calculated using the broadcast channel (BCH). Notify
[0061]
Specifically, as shown in FIGS. 5A and 5B, the offset unit 42 subtracts the offset value from the actual P-CPICH transmission power value to obtain a P-CPICH transmission power report value. As a result, the apparent propagation loss value can be reduced. In addition, the offset unit 42 can increase the apparent propagation loss value by adding the offset value to the actual transmission power value of the P-CPICH to obtain the report value of the P-CPICH transmission power. The mobile station MS performs cell area selection based on the propagation loss of each base station BS.
[0062]
As a result, the base station BS1 can cover a part of the service area of the base station BS2. Therefore, as in the case of the first embodiment, both of the benefits of increased capacity by applying directional beam transmission / reception are also distributed to adjacent base stations BS to which directional beam transmission / reception is not applied. It becomes possible to accommodate users efficiently in the base station BS.
[0063]
(Mobile communication method using mobile communication system)
FIG. 8 is a diagram illustrating an example of a cell area selection flow in the second embodiment.
[0064]
First, the traffic volume measuring unit 13 of the radio network controller 1 measures the traffic volume in each of the base stations BS1 to BS4 (S201). Then, based on the base station information of each base station BS1 to BS4 and the measured value of traffic volume, the report value determination unit 41 of the radio network controller 1 determines the report value of the P-CPICH transmission power of each base station BS1 to BS4. (S202).
[0065]
The wireless network control device 1 notifies the base stations BS1 to BS4 of the report value of the transmission power of the P-CPICH by the report value notification unit 43 (S203). In the base station BS, P-CPICH is transmitted with a predetermined transmission power (S204), and the reporting unit 51 notifies the mobile stations MS1 to MS6 of the report value of the P-CPICH transmission power through the broadcast channel. (S205).
[0066]
In the mobile stations MS1 to MS6, the propagation loss calculation unit 61 calculates the propagation loss from the difference between the RSCP of the P-CPICH and the reported value of the P-CPICH transmission power notified by the broadcast channel (S206). According to the result, the area selection unit 62 performs cell area selection (S207).
[0067]
(Action / Effect)
As described above, even when the traffic distribution varies by controlling the service area by adaptively changing the report value of the P-CPICH transmission power of each base station BS according to the traffic volume that changes with time. It becomes possible to accommodate users efficiently.
[0068]
(Example of change)
In this embodiment, the setting of the P-CPICH transmission power report value is fixedly set to a value predetermined by the type information of each base station BS1 to BS4 (for example, a base station to which directional beam transmission / reception is applied). For the station BS, the report value of the downlink common channel transmission power is set to a value smaller by the offset value YdB). For example, the radio network control device 1 measures the traffic volume in each base station BS, and each base station BS The report value of the P-CPICH transmission power may be adaptively controlled at a constant period based on the base station BS type information and the traffic measurement result.
[0069]
For example, when the traffic volume of the base station BS2 to which omnidirectional beam transmission / reception is not applied is large, the report value of the P-CPICH transmission power of the base station BS1 is set to a value smaller than the actual value, and the base station BS2 The base station BS1 covers a part of the service area of the base station BS2 by setting the report value of the P-CPICH transmission power to a value larger than the actual value.
[0070]
【The invention's effect】
According to the mobile communication system, mobile communication method, control station, base station, and mobile station of the present invention, the base station area to which directional beam transmission / reception is not applied by expanding the service area of the base station to which directional beam transmission / reception is applied Are distributed and connected to base stations to which directional beam transmission / reception is applied, so that both base stations to which directional beam transmission / reception is applied and base stations to which directional beam transmission / reception is not applied can be efficiently performed. Users can be connected.
[0071]
In addition, by controlling the service area adaptively according to the traffic volume, it is possible to connect users efficiently even when the traffic distribution varies.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a mobile communication system in a first embodiment.
FIG. 2 is a block diagram illustrating a configuration example of a radio network control device, a base station, and a mobile station according to the first embodiment.
FIG. 3 is an explanatory diagram showing an example of a service area configuration in the first embodiment.
FIG. 4 is a flowchart showing a procedure of a mobile communication method according to the first embodiment.
FIG. 5 is a graph showing an example of propagation loss in the second embodiment.
FIG. 6 is a block diagram illustrating a configuration example of a radio network controller, a base station, and a mobile station according to the second embodiment.
FIG. 7 is an explanatory diagram showing an example of a service area configuration in the second embodiment.
FIG. 8 is a flowchart showing a procedure of a mobile communication method according to the second embodiment.
FIG. 9 is an explanatory diagram showing a sector cell configuration in the prior art.
FIGS. 10A and 10B are diagrams illustrating an example of a transmission beam pattern in a downlink in the related art, where FIG. 10A is a case of an individual channel, and FIG. 10B is a case of a common channel.
FIG. 11 is an explanatory diagram showing an example of a conventional service area configuration.
[Explanation of symbols]
A1, A2 ... Service area
BS1 to BS4 ... Base station
MS1 to MS6 ... Mobile station
1 ... Wireless network control device
11: Common channel transmission power determination unit
12 ... Base station information storage unit
13. Traffic volume measurement unit
14: Transmission power notification unit
21 ... Transmission power changing unit
22 ... Adaptive antenna array
31. Reception quality calculation section
32 ... Area selection section
33 ... Receiver
41 ... Report value determination section
42 ... Offset part
43: Report value notification section
51. Notification section
61: Propagation loss calculation unit
62 ... Area selection section

Claims (18)

A first base station applying directional beam transmission and reception;
Adjacent to the first base station, a second base station not applying the directional beam transmission and reception,
The service area of the first base station is expanded by expanding the service area of the first base station from the original service area of the first base station according to the traffic amount of the second base station. And area setting means for setting a wider than the service area of the second base station,
The directional beam transmission / reception uses an adaptive antenna array that generates a directional beam pattern unique to each mobile station based on a weight given to each mobile station and transmits / receives a signal via the directional beam pattern. A mobile communication system.   The area setting means reduces the service area of the second base station from the original service area of the second base station according to the traffic volume of the second base station. Item 4. The mobile communication system according to Item 1. The mobile communication system according to claim 1 or 2 , wherein the area setting unit superimposes a service area of the first base station on an original service area of the second base station . Transmission power control means for controlling the transmission power of the downlink common channel transmitted by each base station according to the area set by the area setting means,
The mobile communication system according to any one of claims 1 to 3 , further comprising: an area selection unit that selects an area to be connected according to reception quality based on transmission power of the downlink common channel. According to the area set by the area setting means, a report value control means for controlling the report value of the transmission power of the downlink common channel to be notified to each mobile station,
A propagation loss is calculated based on the reception quality value of the downlink common channel from each base station and the reported value of the downlink common channel transmission power that has been broadcast, and connection should be made according to the calculated propagation loss. the mobile communication system according to any one of claims 1 to 3, characterized in that it has a area selection unit for selecting an area. Traffic volume measuring means for measuring traffic volume at each base station;
A base station information storage unit for storing information on the communication method of each base station,
The said area setting part controls the transmission power or report value of the said downlink common channel based on the traffic amount in each base station, and the kind of each base station, The one of the Claims 1 thru | or 5 characterized by the above-mentioned. The mobile communication system according to 1. A first base station to apply a directional beam transmission and reception, a mobile communication method in the area of the second base station adjacent not to apply the directional beam transmission and reception,
The service area of the first base station is expanded by expanding the service area of the first base station from the original service area of the first base station according to the traffic amount of the second base station. Setting step A wider than the service area of the second base station,
The directional beam transmission / reception uses an adaptive antenna array that generates a directional beam pattern unique to each mobile station based on a weight given to each mobile station and transmits / receives a signal via the directional beam pattern. A mobile communication method characterized by the above.   The step A includes reducing the service area of the second base station from the original service area of the second base station in accordance with the traffic volume of the second base station. 8. The mobile communication method according to 7. The mobile communication method according to claim 7 or 8, wherein in step A, the service area of the first base station is superimposed on the original service area of the second base station . According to the area set in step A, the transmission power of the downlink common channel transmitted by each base station is controlled,
In the mobile station side, controlled according to the reception quality based on the transmission power of the downlink common channel, the mobile communication method according to any one of claims 7 to 9, wherein selecting the area to be connected. Control the transmission value of the downlink common channel to be reported to each mobile station,
In the mobile station, a propagation loss is calculated based on the reception quality value of the downlink common channel from each base station and the reported report value of the downlink common channel transmission power, and according to the calculated propagation loss the mobile communication method according to any one of claims 7 to 9, wherein selecting the area to be connected. The movement according to any one of claims 7 to 11 , wherein, in step A, transmission power of the downlink common channel is controlled based on a traffic amount in each base station and a type of each base station. Communication method. A control station connected to a first base station that applies directional beam transmission and reception and a second base station that is adjacent to the first base station and does not apply directional beam transmission and reception;
The service area of the first base station is expanded by expanding the service area of the first base station from the original service area of the first base station according to the traffic amount of the second base station. And area setting means for setting a wider than the service area of the second base station ,
The directional beam transmission / reception uses an adaptive antenna array that generates a directional beam pattern unique to each mobile station based on a weight given to each mobile station and transmits / receives a signal via the directional beam pattern. A control station characterized by that.   The area setting means reduces the service area of the second base station from the original service area of the second base station according to the traffic volume of the second base station. Item 14. The control station according to Item 13. The control station according to claim 13 or 14, wherein the area setting means superimposes a service area of the first base station on an original service area of the second base station. A transmission power determining unit that determines the transmission power of the downlink common channel transmitted by each base station;
The control station according to any one of claims 13 to 15 , further comprising: a transmission power notification unit that notifies the corresponding base station of the transmission power determined by the transmission power determination unit. A report value determining unit for determining a report value of transmission power of the downlink common channel to be broadcast to each mobile station;
The control station according to any one of claims 13 to 15 , further comprising: a report value notification unit that reports a report value determined by the report value determination unit to a mobile station via a corresponding base station. A traffic volume measurement unit for measuring the traffic volume at each base station;
A base station information storage unit for storing information on the communication method of each base station,
The area setting unit, a traffic volume at each base station, based on the type of each base station, according to any one of claims 13 to 17 and sets the transmission power of the downlink common channel Control station.

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