JP2008011231A - Wireless communication method and base station device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a mobile station device to be improved in accuracy in receiving paging signals. <P>SOLUTION: In a wireless communication method by the mobile station device 100 and a base station device 10 equipped with an adaptive array antenna 20 used for exchanging signals with the mobile station device 100, the base station device 10 receives location registering signals transmitted from the mobile station device 100 for registering its location, calculates the weight of each antenna element of the adaptive array antenna 20 on the basis of the received location registering signals, and transmits the paging signals according to the calculated weight to the mobile station device 100 through the adaptive array antenna 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for transmitting a paging signal by a base station apparatus.

The incoming call to the mobile station apparatus is transmitted by a paging signal transmitted from the base station apparatus. The paging signal is transmitted all at once from not only the base station device in which the position of the mobile station device is registered, but also the base station devices in the vicinity thereof. In order to suppress the reception power of the paging signal of the mobile station device, it is desirable that the transmission interval of the paging signal is long, and the necessity of a communication technique that can reliably receive one paging signal is increasing. Conventionally, a technique has been proposed in which a base station apparatus including an adaptive array antenna transmits a paging signal with a predetermined plurality of radiation patterns via the adaptive array antenna to increase the reception probability of the paging signal (Patent Document 1). reference).
JP 2001-127681 A

  However, in the above prior art, since the paging signal is transmitted without considering the position of the mobile station apparatus, the reception probability of the paging signal may not always improve.

  The present invention has been made in view of the above problems, and an object of the present invention is to transmit a paging signal with a directivity pattern reflecting the position of the mobile station apparatus, and improve the reception accuracy of the paging signal in the mobile station apparatus. To provide a wireless communication method and a base station apparatus.

  In order to solve the above problems, a radio communication method according to the present invention is a radio communication method using a mobile station apparatus and a base station apparatus provided with an adaptive array antenna that transmits and receives signals to and from the mobile station apparatus, A receiving step in which the base station device receives a location registration signal for location registration of the mobile station device transmitted by the mobile station device; and the base station device adds a location registration signal received in the receiving step. A weight calculation step for calculating a weight of each antenna element of the adaptive array antenna, and the base station device sends a paging signal to the mobile station via the adaptive array antenna by the weight calculated in the weight calculation step. And a paging signal transmission step for transmitting to the apparatus.

  The base station apparatus according to the present invention is a base station apparatus including an adaptive array antenna that transmits and receives signals to and from the mobile station apparatus, and is used for position registration of the mobile station apparatus transmitted by the mobile station apparatus. Calculated by a receiving means for receiving a position registration signal, a weight calculating means for calculating the weight of each antenna element of the adaptive array antenna based on the position registration signal received by the receiving means, and the weight calculating means Transmitting means for transmitting a paging signal to the mobile station apparatus via the adaptive array antenna by weighting.

  In the present invention, the base station apparatus includes an adaptive array antenna. And a base station apparatus receives the position registration signal transmitted from a mobile station apparatus by an adaptive array antenna. Then, the weight of each antenna element of the adaptive array antenna is calculated based on the received position registration signal. Then, the paging signal for the mobile station is transmitted with a weight calculated based on the position registration signal.

  According to the present invention, a base station apparatus having an adaptive array antenna transmits a paging signal with a directivity pattern reflecting the position of the mobile station apparatus based on the position registration signal received from the mobile station apparatus. It is possible to improve the receiving accuracy of the paging signal.

  In the aspect of the invention, the calculation step calculates a plurality of weights based on the location registration signal, and the paging signal transmission step varies depending on each of the plurality of weights calculated by the calculation step. The paging signal is transmitted at a timing. As a result, the possibility that the null of the paging signal overlaps in the direction of the mobile station apparatus can be reduced, and the reception accuracy of the paging signal in the mobile station apparatus can be improved.

  In the aspect of the invention, the calculating step may calculate the weight of each antenna element so that a directivity pattern in which a beam is directed in the arrival direction of the position registration signal is formed. . As a result, when transmitting a paging signal, the beam can be directed in the direction of arrival of the location registration signal transmitted by the mobile station apparatus, and the receiving accuracy of the paging signal in the mobile station apparatus can be improved.

  Further, in one aspect of the present invention, the calculating step calculates the weight of each antenna element so that a directivity pattern in which a null is directed toward an arrival direction of an interference wave of the position registration signal is formed. Features. As a result, when transmitting a paging signal, it is possible to improve the reception accuracy of the paging signal in the mobile station apparatus by directing null in the arrival direction of the interference wave of the location registration signal transmitted by the mobile station apparatus.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.

  FIG. 1 shows an example of cell arrangement of a mobile communication system according to this embodiment. As shown in FIG. 1, base station apparatuses 10A, 10B, and 10C are arranged in cells 200A, 200B, and 200C, respectively. Each of the base station devices 10 is a base station device that includes an adaptive array antenna and performs wireless communication with the mobile station device 100. Hereinafter, the base station devices 10A, 10B, and 10C are referred to as the base station device 10 when generalized.

  The mobile station device 100 is located in the cell 200A and is registered in the base station device 10A. In the mobile communication system, in order to transmit a call to the mobile station apparatus 100 that can move freely, the position is registered in the base station apparatus 10 that is close to the current position of the mobile station apparatus 100. The mobile station device 100 transmits a location registration signal to the nearby base station device 10 in order to perform location registration. Then, the base station device 10 that has received the location registration signal transmitted by the mobile station device 100 acquires the identifier of the mobile station device 100 included in the location registration signal, and moves the mobile station device 100 to the location registration database of the mobile communication system. The identifier of the station device is registered in association with its own identifier. When the location registration of the mobile station device 100 is performed in the location registration database, the base station device 10 that performed the location registration returns a response signal of the location registration signal to the mobile station device 100.

  In the present embodiment, it is assumed that the cells 200A, 200B, and 200C form one paging area. As shown in FIG. 1, when transmitting a call to the mobile station apparatus 100, not only the base station apparatus 10A in which the mobile station apparatus 100 registers a position, but also base station apparatuses 10B in the same paging area, A paging signal is also transmitted simultaneously from 10C.

  FIG. 2 shows a system configuration diagram of a VoIP (Voice over IP) system including the base station device 10 and the mobile station device 100. As shown in FIG. 2, the VoIP system includes a SIP (Session Initiation Protocol) server 300, an IP network 400 such as the Internet, a base station device 10, and a mobile station device 100.

  The SIP server 300 is a server that controls a VoIP communication call. When the SIP server 300 receives a call request to the mobile station device 100 via the IP network 400, the SIP server 300 inquires of the location registration database, and the base station device 10 (where the mobile station device 100 is registered) In this example, the base station apparatus 10A) is specified. Then, the SIP server transmits an INVITE signal to the identified base station apparatus 10. The INVITE signal is a signal requesting establishment of a VoIP communication session. Receiving the INVITE signal, the base station apparatus 10 also transmits a paging signal transmission request to other base station apparatuses 10 included in the same paging area. Each base station apparatus 10 (base station apparatuses 10A, 10B, and 10C in the above example) transmits a paging signal to the mobile station apparatus 100 all at once.

  FIG. 3 shows an example of a structural unit of a transmission frame including a slot in which a paging signal is transmitted. In the present embodiment, it is assumed that the paging signal is transmitted by a time division method using two channels. FIG. 3 shows a frame configuration of two channels, where the upper side is a first channel and the lower side is a second channel. The frequency used is different between the first channel and the second channel, but the basic structure of the frame is the same, and the unit frame (5 ms) is allocated to each of the upstream signal and the downstream signal by 3 slots. It consists of a total of 6 slots. In this embodiment, the paging signal is time-divided with the first half of slot 2 in the transmission slot of the first channel as the main slot and the second half of slot 2 in the transmission slot of the second channel as the subslot. Sent by method.

  In the present invention, the paging signal is transmitted with a directivity pattern formed by an adaptive array antenna. The directivity pattern is formed by weighting a signal transmitted by each antenna element of the adaptive array antenna. The present invention is characterized in that a weight for transmitting a paging signal is calculated based on a location registration signal received from the mobile station apparatus 100.

  In FIG. 4, the directivity pattern of the paging signal transmitted by each of the base station apparatuses 10 is shown. In FIG. 4, the solid line indicates the directivity pattern of the main slot, and the broken line indicates the directivity pattern of the subslot. As shown in FIG. 4, different directivity patterns are formed in the main slot and the subslot by using different weighting calculation methods based on the position registration signal received from the mobile station device 100. . If the paging signal is transmitted by forming different directivity patterns in the main slot and the subslot as described above, the possibility that nulls are directed toward the mobile station apparatus 100 in both the main slot and the subslot is reduced. Reception accuracy is improved.

  In order to realize the above processing, the configuration of the base station apparatus of the present invention will be described below.

  FIG. 5 is a block diagram illustrating a configuration of the base station apparatus 10. As illustrated in FIG. 5, the base station apparatus 10 includes an adaptive array antenna 20, a wireless communication unit 22, an adaptive array processing unit 24, a control unit 26, and a communication unit 30.

  The adaptive array antenna 20 has a plurality of antenna elements 20-1, 20-2, 20-3,... 20-n arranged in an array so that the directivity can be dynamically changed according to changes in the radio wave environment. Antenna system. The radio communication unit 22 controls the adaptive array antenna 20 in a time division manner to switch between transmission and reception processing. The adaptive array processing unit 24 adjusts the weighting of each antenna element of the adaptive array antenna 20. The control unit 26 includes a processor, a memory, and the like, and controls each unit of the base station apparatus 10. In addition, the control unit 26 includes a weighting storage unit 28 realized by a storage unit such as a memory. The communication unit 30 is a network interface that transmits and receives signals to and from the SIP server 300 and a location registration database server (not shown).

  Details of processing performed in each configuration of the base station apparatus 10 will be described below with reference to FIGS. 6 and 7.

[Weighting calculation process]
In base station apparatus 10, the weight of adaptive array antenna 20 for the paging signal transmitted to mobile station apparatus 100 is calculated based on the position registration signal received from mobile station apparatus 100. The location registration signal is transmitted when the mobile station device 100 moves from the cell 200. For example, the mobile station apparatus 100 transmits a location registration signal when the base station apparatus 10 that transmits a signal having the highest reception level changes based on the reception levels of control signals received from a plurality of base station apparatuses 10. It is good to do.

  FIG. 6 is a flowchart relating to processing when the base station apparatus 10 calculates the weight of the adaptive array antenna of the paging signal transmitted to the mobile station apparatus 100.

  Each base station apparatus 10 receives the location registration signal transmitted by the mobile station apparatus 100 via the adaptive array antenna 20 (S101). Then, in each base station device 10, the received location registration signal is analyzed by the processor of the control unit 26, and the identifier of the mobile station device 100 included in the location registration signal is acquired (S102).

  The adaptive array processing unit 24 calculates a weight vector for each antenna element according to a predetermined weight calculation algorithm based on the received position registration signal (S103). The weight calculation algorithm may be a known algorithm for realizing beam forming and null steering. For example, for beam forming, MMSE (Minimum Mean Square Error), CMA (Constant Modulus Algorithm), etc., for null steering, in addition to these, MSN (Maximum Signal-to-Noise Ratio), DCMP (Directional Constrained Minimization of Power) ), PI (Power Inversion) and the like may be used.

  In the present embodiment, two weighting vectors are calculated using different weighting calculation algorithms for the main slot and subslot based on the position registration signal. Then, the two calculated weighting vectors are stored in the weighting storage unit in association with the identifier of the mobile station apparatus 100 acquired from the position registration signal (S104).

[Paging signal transmission processing]
FIG. 7 is a sequence diagram regarding paging signal transmission processing performed by the SIP server 300, the base station apparatus 10, and the mobile station apparatus 100.

  When the SIP server 300 receives a request for VoIP communication designating the mobile station device 100 (S201), the SIP server 300 inquires of the location registration database and registers the base station device 10 in which the mobile station device 100 is registered (in this case, the base station device 10A). ) Is specified (S202). Then, the SIP server 300 transmits an INVITE signal to the identified base station apparatus 10 (S203). The INVITE signal includes information designating the mobile station device 100 as destination information for VoIP communication.

  When the base station apparatus 10A receives the INVITE signal, the base station apparatus 10A requests the mobile station apparatus 100 to transmit a paging signal to the base station apparatuses 10B and 10C in the same paging area (S204). Then, in base station apparatuses 10A, 10B, and 10C, a weighting vector for transmitting a paging signal stored in association with mobile station apparatus 100 is read from the memory (S205). In the present embodiment, different weighting vectors for the main slot and for the subslot are read, and these are hereinafter referred to as W1 and W2. In each base station apparatus 10, in the main slot, the paging signal is transmitted after being multiplied by the weighting vector W1. In the subslot, the paging signal is transmitted after being multiplied by the weighting vector W2 (S206).

  And the mobile station apparatus 100 will connect with one of the base station apparatuses 10, if the paging signal in which directivity was formed is received (S207). In the present embodiment, the connection is made to the base station device 10A, but it may be connected to another base station device 10. In that case, when the location registration is not performed in the connected base station apparatus 10, a handover is performed. Then, the mobile station apparatus 100 receives the VoIP INVITE signal transmitted from the accessed base station apparatus 10 (S207).

  According to the radio communication method according to the embodiment of the present invention described above, the position of the mobile station apparatus according to the weight calculated based on the position registration signal received from the mobile station apparatus by the base station apparatus including the adaptive array antenna. The paging signal can be transmitted with the directivity pattern reflecting the above, and the receiving accuracy of the paging signal in the mobile station apparatus can be improved.

  In addition, this invention is not limited to said embodiment.

  In the above embodiment, the paging signal is time-division transmitted using two channels, but may be sequentially transmitted with different weights on one channel.

  In the above embodiment, for convenience of explanation, the description is made using only one mobile station apparatus. However, the technique of the present invention is naturally applicable even when a plurality of mobile station apparatuses exist. In that case, the weighting vector calculated based on the position registration signal received from each mobile station apparatus may be stored in association with the identifier of each mobile station apparatus.

It is a figure which shows an example of the cell arrangement | positioning of a mobile communication system. It is a system configuration figure of a VoIP system. It is a figure which shows an example of the structural unit of a transmission frame. It is a figure which shows the directivity pattern of the paging signal transmitted by each base station apparatus. It is a block diagram which shows the structure of a base station apparatus. It is a flowchart of a weight calculation process. It is a sequence diagram of the transmission process of a paging signal.

Explanation of symbols

  10A, 10B, 10C Base station apparatus, 20 adaptive array antenna, 20-1, 20-2, 20-3, ..., 20-n antenna element, 22 wireless communication unit, 24 adaptive array processing unit, 26 control unit , 28 Weight storage unit, 30 communication unit, 100 mobile station device, 200A, 200B, 200C cell, 300 SIP server, 400 IP network.

Claims (5)

A wireless communication method using a mobile station device and a base station device including an adaptive array antenna that transmits and receives signals to and from the mobile station device,
The base station device receives a location registration signal for location registration of the mobile station device transmitted by the mobile station device; and
The base station apparatus calculates a weight of each antenna element of the adaptive array antenna based on the position registration signal received in the reception step;
A paging signal transmission step in which the base station device transmits a paging signal to the mobile station device via the adaptive array antenna with the weight calculated in the weight calculation step;
A wireless communication method comprising: The wireless communication method according to claim 1,
The calculating step includes:
Calculating a plurality of weights based on the location registration signal;
The paging signal transmission step includes:
Transmitting the paging signal at a different timing depending on each of the plurality of weights calculated in the calculating step;
A wireless communication method. The wireless communication method according to claim 1 or 2,
The calculating step includes:
Calculating a weight of each antenna element so as to form a directivity pattern in which a beam is directed in the direction of arrival of the position registration signal;
A wireless communication method. The wireless communication method according to any one of claims 1 to 3,
The calculating step includes:
Calculating the weight of each antenna element so that a directivity pattern in which nulls are directed in the direction of arrival of the interference wave of the position registration signal is formed;
A wireless communication method. A base station device comprising an adaptive array antenna that transmits and receives signals to and from a mobile station device,
Receiving means for receiving a location registration signal for location registration of the mobile station device transmitted by the mobile station device;
A weight calculating means for calculating a weight of each antenna element of the adaptive array antenna based on the position registration signal received by the receiving means;
Transmitting means for transmitting a paging signal to the mobile station apparatus via the adaptive array antenna by the weight calculated by the weight calculating means;
A base station apparatus comprising:

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