JP4458901B2 - Base station apparatus and transmission source identification method - Google Patents

Description

  The present invention relates to a base station apparatus and a transmission source identification method.

  For example, in a base station apparatus used in a mobile communication system such as a PHS system using an SDMA (Space Division Multiple Access) system, a UW (Unique Word, synchronization) that is different for each mobile station apparatus that is a transmission source. Word) may be used to separate signals from each mobile station apparatus. Further, even in a base station apparatus used in a mobile communication system such as CDMA2000 or wireless LAN that uses a spread spectrum system, a signal from each apparatus is used by using a different spreading code for each mobile station apparatus or computer apparatus as a transmission source. May be separated.

  As described above, in a mobile communication system that superimposes a plurality of transmission sources on electromagnetic waves of the same frequency, there are cases where separation of mobile station devices and the like in the base station device is performed by using different transmission source identification information. Conventionally, mobile station apparatuses that communicate with one base station apparatus are identified by using different transmission source identification information for each base station apparatus.

Patent Document 1 discloses an invention relating to a method of assigning a user to the same information channel or speech channel as other users by spatial multiplexing in an SDMA communication system.
JP 2002-271446 A

  However, in the above conventional method, it is possible to separate a signal from a mobile station apparatus communicating with the base station apparatus, but for transmission from a mobile station apparatus communicating with another base station apparatus. Such a transmission source cannot be separated by the transmission source identification information. In particular, the influence on communication due to the inability to separate signals from mobile station devices communicating with base station devices in the geographical vicinity of the other base station devices is significant.

  The present invention has been made in view of the above-described problems, and its object is to provide a base station apparatus and transmission source identification that enable identification of a transmission source by transmission source identification information for a communication apparatus that communicates with another base station apparatus. It is to provide a method.

The present invention for solving the above-described problems is a wireless communication system including a plurality of base station devices connected via a network and a plurality of mobile station devices each wirelessly communicating with one of the plurality of base station devices. Wireless communication between any one of the plurality of base station devices used in the wireless communication system, and another base station device in the wireless communication system and a first mobile station device in the wireless communication system And at least a transmission source from a radio signal wirelessly transmitted between the other base station apparatus and the first mobile station apparatus and receiving the radio signal transmitted by radio in the receiver an acquisition unit that acquires first sender identification information used is included in the radio signals in order to identify, in a wireless communication with the second mobile station apparatus in the wireless communication system, at least the sender A storage unit for storing candidate identification information group candidate identification second is a candidate of the transmission source identification information used is included in the radio signal to another is more conserved, said acquired by the acquisition unit A selection unit that selects second transmission source identification information having an inner product with the first transmission source identification information that is smaller than a threshold value from the candidate identification information group of the storage unit, and the second transmission source that is selected by the selection unit And a transmitter that wirelessly transmits identification information to the second mobile station device .

In the base station apparatus of the present invention, the selection unit selects the second transmission source identification information based on reception power of the first transmission source identification information received by the reception unit. it can.

Further, in the base station apparatus of the present invention, the candidate identification information group stored in the storage unit is created based on a sum of inner products of the candidate identification information included in the candidate identification information group. can do.

The communication method of the present invention is used in a wireless communication system including a plurality of base station devices connected via a network and a plurality of mobile station devices each communicating wirelessly with any of the plurality of base station devices. A communication method of any one of the plurality of base station devices , wherein the base station device is in radio communication between another base station device in the radio communication system and a first mobile station device in the radio communication system. A reception step of receiving a radio signal transmitted by radio , and at least a transmission source is identified from the radio signal transmitted between the other base station device and the first mobile station device and received in the reception step an acquisition step of acquiring first sender identification information used is included in the radio signals to, in a wireless communication with the second mobile station apparatus in the wireless communication system, at least the sender The second candidate identification information is a candidate of the transmission source identification information from among the candidate identification information group contained more, the acquired first transmission source identification by the acquisition process used is included in the radio signals in order to identify A selection step of selecting second transmission source identification information whose inner product with information is smaller than a threshold value, and a transmission step of wirelessly transmitting the second transmission source identification information selected in the selection step to the second mobile station device ; a communication method comprising a.

  Embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, mobile communication system 4 according to the present embodiment includes a plurality of mobile station apparatuses 1, a plurality of base station apparatuses 2 and a communication network 3. The base station device 2 communicates with the normal communication network 3 and the mobile station device 1.

  As shown in FIG. 2, the mobile station device 1 includes a control unit 11, a communication unit 12, a storage unit 13, an operation unit 14, and a display unit 15. The control unit 11 controls each unit of the mobile station device 1 and executes processing related to a call and data communication. The communication unit 12 includes an aerial line, and in accordance with an instruction input from the control unit 11, modulates a voice signal, a communication packet, and the like and outputs the modulated signal or the voice signal arriving at the aerial line. A process of receiving and demodulating and outputting to the control unit 11 is performed. The storage unit 13 operates as a work memory for the control unit 12. The storage unit 13 holds programs and parameters related to various processes performed by the control unit 12. The operation unit 14 is, for example, a numeric keypad, and receives a telephone number or character string input from a user and outputs it to the control unit 12. The display unit 15 includes a liquid crystal display device, for example, and displays and outputs information according to a signal input from the control unit 12.

  Next, as shown in FIG. 3, the base station device 2 includes a control unit 21, a network interface unit 22, a wireless communication unit 23, and a storage unit 24. The control unit 21 controls each unit of the base station apparatus 2 and executes processing related to telephone calls and data communication. The network interface unit 22 is connected to the communication network 3 and receives an audio signal, a communication packet, and the like from the communication network 3 and outputs them to the control unit 21, or according to an instruction from the control unit 21. A packet or the like is transmitted to the communication network 3. The wireless communication unit 23 includes an antenna, receives and demodulates a voice signal, a communication packet, and the like from the mobile station apparatus 1 and outputs them to the control unit 21 or according to an instruction input from the control unit 21. Processing such as modulating an audio signal or a communication packet input from the unit 21 and outputting it via an antenna is performed. The storage unit 24 operates as a work memory for the control unit 21. Further, the storage unit 24 holds programs and parameters related to various processes performed by the control unit 21.

  In the mobile communication system 4, the communication area of the base station device 2 is a range where the base station device 2 and the mobile station device 1 can communicate. And the area where each base station apparatus 2 can communicate with the mobile station apparatus 1 usually overlaps in many cases. An example is shown in FIG. In FIG. 4, the communication area 2-1 of the base station apparatus 2-1 and the communication area 2-2 of the base station apparatus 2-2 overlap. For this reason, when the mobile station apparatus 1-1 and the mobile station apparatus 1-2 are in the overlapping area, it is possible to communicate with both the base station apparatus 2-1 and the base station apparatus 2-2. Further, even when the mobile station device 1-1 and the mobile station device 1-2 are not in the overlapping area, it is usually possible that the electromagnetic waves from each mobile station device 1 reach the base station device 2 that is not communicating. For this reason, even when the mobile station apparatus 1-1 communicates with the base station apparatus 2-1, and the mobile station apparatus 1-2 communicates with the base station apparatus 2-2, the mobile station apparatus 2-1 moves in the base station apparatus 2-1. The electromagnetic wave from the station apparatus 1-2 is also received, and the base station apparatus 2-2 may also receive the electromagnetic wave from the mobile station apparatus 1-1.

  In such a case, it is necessary for each base station device 2 to separate signals from electromagnetic waves from the mobile station device 1-1 and the mobile station device 1-2. As one of the methods for separating the signals due to the electromagnetic waves from the respective mobile station devices 1, there is a method of separating the signals by setting individual transmission source identification information for each mobile station device 1. For example, in the SDMA system, UW is used as transmission source identification information. In the CDMA system, a PN code is used. In the conventional PHS, the UW is a unique bit string for each base station device 2, and the mobile station device 1 with which the communicating base station device 2 is different may use the same UW. Cannot separate signals from each mobile station apparatus 1.

  FIG. 5 is a specific example of UW used in PHS. In PHS, the number of UW bits differs between the control channel and the communication channel. Specifically, it is 32 bits for the control channel and 16 bits for the communication channel. If the UW is different, the signal from each mobile station device 1 can be separated.

  And in this invention, it is possible to isolate | separate the signal by the electromagnetic waves from the mobile station apparatus 1 which is communicating with the different base station apparatus 2 using the method mentioned later.

  FIG. 6 is a functional block diagram of base station apparatus 2 used in the present embodiment. The base station apparatus 2 is functionally configured to include a reception unit 30, an acquisition unit 32, a selection unit 34, a storage unit 36, and a transmission unit 38.

  The receiving unit 30 receives electromagnetic waves from other base station devices 2 and outputs them to the acquiring unit 32. Specifically, a broadcast channel transmitted by another base station device 2 may be received, or an electromagnetic wave for communication with the mobile station device 1 may be received. The target to be received may be the base station device 2 in a range where the electromagnetic waves from the base station device 2 can reach, or receive the electromagnetic waves from the mobile station device 1 communicating with the base station device 2. Also good. The receiving unit 30 receives an electromagnetic wave from another base station device 2 in order to acquire transmission source identification information used by the other base station device 2 in the acquiring unit 32. Therefore, the method is not limited to the method of receiving the electromagnetic wave from the other base station device 2 as long as it can acquire the transmission source identification information used by the other base station device 2, for example, other base station device 2 It is good also as receiving the electromagnetic waves from the mobile station apparatus 1 which is communicating with the station apparatus 2, or receiving the electromagnetic waves containing the transmission source identification information which another base station apparatus 2 uses via the communication network 3. It is good to do. In this case, the transmission source identification information can be managed by a server or the like provided in the communication network 3. Then, processing such as demodulation of the received electromagnetic wave is performed, and a signal included in the electromagnetic wave is output to the acquisition unit 32.

  Then, the acquisition unit 32 acquires the transmission source identification information from the electromagnetic wave input from the reception unit 30. When the sender identification information is UW, for example, it may be 32 bits as described above, or it may be 16 bits. Therefore, the receiving unit 30 receives the electromagnetic wave including each, and the acquiring unit 32 Is preferably extracted. Each electromagnetic wave contains a different UW. FIG. 7 is an image of UW that is transmission source identification information included in the received electromagnetic wave. Then, the acquisition unit 32 outputs the acquired transmission source identification information to the selection unit 34.

  The receiving unit 30 may acquire RSSI (Receive Signal Strength Identifier, received power) of the received electromagnetic wave, output the signal to the acquiring unit 32, and output the RSSI. The RSSI is used in the selection unit 34 described later.

  The selection unit 34 selects transmission source identification information used in the base station apparatus 2 based on the transmission source identification information input from the acquisition unit 32. In the selection, RSSI can also be considered. A specific selection method will be described below.

  First, the case where the transmission source identification information is managed as a transmission source identification information group and the case where it is not the case are considered. When not managing as a transmission source identification information group, for example, transmission source identification information different from the transmission source identification information acquired by the acquisition unit 32 can be selected. When selecting the transmission source identification information, it is preferable to determine the transmission source identification information to be selected according to the similarity to the transmission source identification information acquired by the acquisition unit 32. This is because, if the degree of similarity is low, there is a high possibility that identification is possible even when a bit error or the like occurs when identifying the transmission source of the electromagnetic wave by the transmission source identification information. Specifically, for example, the similarity can be determined by the orthogonality between the transmission source identification information. The orthogonality is determined by the inner product of the transmission source identification information. Hereinafter, an example of a method for obtaining the inner product will be described by taking a 16-bit UW used in the four-phase phase modulation method in which the transmission source identification information is used in PHS as an example.

  In the four-phase phase modulation method, the 2-bit information S is expressed as shown in Equation (1). Here, e is a Napier number, j is an imaginary number, f is a phase, and f takes a numerical value of π / 4, 3π / 4, 5π / 4, 7π / 4 to express 2-bit information. ing.

  A 16-bit UW is an array of 8 S's. The inner product of the two UWs is as follows. Note that the phase of one UW is f1i (i = 1 to 8), and the phase of the other UW is f2i (i = 1 to 8). * Represents a complex conjugate.

  The smaller the inner product represented by the above formula (2), the higher the orthogonality between the two UWs. That is, the similarity is low. For this reason, when selecting the transmission source identification information, the selection unit 34 preferably selects the one whose inner product with the transmission source identification information acquired by the acquisition unit 32 is equal to or less than a predetermined threshold. Of course, it is more preferable that the inner product is zero.

  For example, the same transmission source identification information as the transmission source identification information acquired by the acquisition unit 32 may be selected. In this case, for example, it is desirable to select one having orthogonality equal to or less than a predetermined threshold as described above. For example, the acquisition unit 32 outputs the RSSI input from the reception unit 30 to the selection unit 34. And the selection part 34 can memorize | store this RSSI with transmission origin identification information, and can also select from transmission origin identification information which the base station apparatus 2 with low RSSI uses. The low RSSI means that the electromagnetic wave received by the base station apparatus 2 is weak, and it is considered that the influence on the communication due to the fact that the signal cannot be separated is small.

  Next, the case where it manages as a transmission source identification information group is demonstrated.

  In the storage unit 36, the transmission source identification information is stored and managed as a transmission source identification information group. FIG. 8 is an example of a table stored at this time. In the figure, a UW group that is a group of M transmission source identification information and a pattern of N transmission source identification information are stored in each group. Each source identification information group is preferably stored so that the degree of similarity is low. In other words, it is preferable to store such that the orthogonality is high. The orthogonality between the transmission source identification information groups can be represented by the sum of the inner products of the elements of the direct product set of the transmission source identification information included in each transmission source identification information group. Specifically, taking UW group 1 and UW group 2 in FIG. 8 as an example, equation (3) is obtained.

  Based on the transmission source identification information acquired from the acquisition unit 32, the selection unit 34 acquires the transmission source identification information group used by at least a part of the other base station device 2 by reading from the storage unit 36. . That is, the transmission source identification information group including the transmission source identification information acquired from the acquisition unit 32 is acquired by reading from the storage unit 36. Then, transmission source identification information to be selected is determined based on the transmission source identification information group. Specifically, it is preferable to select a transmission source identification information group having a low similarity to the transmission source identification information group. When the transmission source identification information acquired from the acquisition unit 32 is not included in the storage unit 36, a transmission source identification information group having a low degree of similarity to the transmission source identification information may be selected. The similarity in this case can also be determined by the sum of inner products of the transmission source identification information and the transmission source identification information included in the transmission source identification information group. Then, the transmission source identification information included in the transmission source identification information group is read and determined as transmission source identification information to be selected.

  Also in this case, for example, the same transmission source identification information group as the transmission source identification information group including the transmission source identification information acquired by the acquisition unit 32 can be selected. In this case, as described above, it is desirable to select, for example, those in which the orthogonality between the transmission source identification information groups is equal to or less than a predetermined threshold. The RSSI is output to the selection unit 34, and the selection unit 34 stores the RSSI together with the transmission source identification information, and selects from the transmission source identification information group including the transmission source identification information used by the base station apparatus 2 having a low RSSI. It can also be.

  The above process will be described more specifically with reference to a flowchart.

  FIG. 9 is an example of a flow diagram showing a flow of processing for acquiring a UW of another base station apparatus 2 in the PHS.

  First, it is determined whether it is within a predetermined time (S100). The predetermined time represents a limit on the elapsed time from the start of the processing shown in the flowchart. If the elapsed time is within the predetermined time, it is determined whether or not an electromagnetic wave from another base station apparatus is received (S102). If the electromagnetic wave is received, it is the transmission source identification information included in the electromagnetic wave. UW, RSSI, and CSID (Cell Station Identification, base station identification number) are read and stored in association with each other as a neighboring base station information list (S103). This process is repeated until a predetermined time has elapsed.

  And if predetermined time passes, the process which determines UW used with the said base station apparatus 2 will be performed. An example of this processing is shown in FIG.

  FIG. 10 is an example of processing for selecting a UW so as not to select a UW having the maximum RSSI. First, the neighboring base station information list is sorted in descending order of RSSI (S120). Then, another base station busy UW registration table is created (S122). In the other base station busy UW registration table, UW, RSSI, and CSID are stored in association with each other. Then, the neighboring base station information list is selected in descending order of RSSI (S130), and is registered in the other base station busy UW registration table (S132). At this time, it may be deleted from the neighboring base station information list. Then, it is determined whether there is no remaining in the neighboring base station information list (S124). Alternatively, it is determined whether the maximum number that can be registered in the other base station in-use UW registration table is registered (S126). When there is no remaining in the neighboring base station information list or when the maximum number (UW registration threshold) that can be registered in the other base station in-use UW registration table is registered, it is registered in the other base station in-use UW registration table. An unselected UW pattern, that is, transmission source identification information is selected. When there is a remaining in the neighboring base station information list and the maximum number that can be registered in the other base station in-use UW registration table is not registered, the processes of S130 and S132 are repeated. In this way, the transmission source identification information can be selected so that the transmission source identification information used by the base station apparatus 2 having a high RSSI is not used.

  As described above, the transmission source identification information selected by the selection unit 34 is output to the transmission unit 38. Then, the transmission unit 38 notifies the mobile station apparatus 1 of the transmission source identification information. Since the transmission source identification information is preferably different for each mobile station apparatus 1, the selection unit 34 preferably selects different transmission source identification information for each mobile station apparatus 1 and outputs it to the transmission unit 38. It is.

  Although not shown, the mobile station apparatus 1 notified of the transmission source identification information can communicate using the transmission source identification information. In this way, the base station device 2 includes not only the mobile station device 1 communicating with the base station device 2 but also the mobile station device 1 communicating with other base station devices 2. Each mobile station apparatus 1 can receive a signal including different transmission source identification information. For this reason, it becomes possible to identify the transmission source by the transmission source identification information for the communication device that communicates with other base station devices.

  The present invention is not limited to the above embodiment. For example, the transmission source identification information may have candidates stored in advance, and may be selected from the stored transmission source identification information, or a transmission source having high orthogonality with the transmission source identification information acquired by the acquisition unit 32 You may select by calculating identification information. Further, although the above embodiment has been described by taking the SDMA PHS as an example, a transmission source having a plurality of base station apparatuses such as a mobile communication system using the CDMA method and using different transmission source identification information The present invention is applicable to any radio communication system as long as the radio communication system needs to be separated. The source identification information is used not only for uplink communication (communication from the mobile station apparatus to the base station apparatus) but also for downlink communication (communication from the base station apparatus to the mobile station apparatus). Different transmission source identification information can be used for the transmission source identification information for each base station apparatus selected by the present invention. Moreover, the process demonstrated by the said embodiment can also be performed by the exchange and server which are installed on the communication network 3, for example.

1 is a configuration diagram of a mobile communication system according to an embodiment of the present invention. FIG. 2 is a configuration block diagram of a mobile station apparatus according to an embodiment of the present invention. It is a block diagram of the configuration of a base station apparatus according to an embodiment of the present invention. It is explanatory drawing of the communication area which concerns on embodiment of this invention. It is a signal format figure of the signal used by PHS. It is a functional block diagram of the base station apparatus which concerns on embodiment of this invention. It is explanatory drawing of the transmission source identification information contained in the received electromagnetic wave which concerns on embodiment of this invention. It is a figure which shows the table which memorize | stores the transmission source identification information which concerns on embodiment of this invention as a transmission source identification information group. It is a flowchart of the process which concerns on embodiment of this invention. It is a flowchart of the process which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile station apparatus, 2 Base station apparatus, 3 Communication network, 4 Mobile communication system, 11, 21 Control part, 12 Communication part, 13, 24, 36 Storage part, 14 Operation part, 15 Display part, 22 Network interface part , 23 Wireless communication unit, 30 reception unit, 32 acquisition unit, 34 selection unit, 38 transmission unit.

Claims (4)

A plurality of base station devices used in a wireless communication system including a plurality of base station devices connected via a network and a plurality of mobile station devices each communicating wirelessly with any of the plurality of base station devices; One of the base station devices,
A receiving unit for receiving a radio signal transmitted by radio in radio communication between another base station apparatus in the radio communication system and the first mobile station apparatus in the radio communication system;
A first wireless signal that is wirelessly transmitted between the other base station device and the first mobile station device and is included in the wireless signal to identify at least a transmission source from the wireless signal received by the receiving unit. An acquisition unit for acquiring transmission source identification information;
In wireless communication with the second mobile station apparatus in the wireless communication system, at least a plurality of candidate identification information that are candidates for second transmission source identification information used in a wireless signal for identifying the transmission source are stored. A storage unit for storing the candidate identification information group,
A selection unit that selects , from the group of candidate identification information in the storage unit, second transmission source identification information whose inner product with the first transmission source identification information acquired by the acquisition unit is smaller than a threshold ;
A base station apparatus comprising: a transmission unit that wirelessly transmits the second transmission source identification information selected by the selection unit to the second mobile station device. The base station apparatus according to claim 1, wherein the selection unit selects the second transmission source identification information based on reception power of the first transmission source identification information received by the reception unit. . The candidate identification information group stored in the storage unit is created based on a sum of inner products of the candidate identification information included in the candidate identification information group. The base station apparatus as described. A plurality of base station devices used in a wireless communication system including a plurality of base station devices connected via a network and a plurality of mobile station devices each communicating wirelessly with any of the plurality of base station devices; A communication method of any of the base station devices,
A receiving step of receiving a radio signal transmitted by radio in radio communication between another base station apparatus in the radio communication system and a first mobile station apparatus in the radio communication system;
Wherein the wireless transmission with another base station apparatus and the first mobile station, from the radio signal received at the reception step, a first used is included in the radio signal to identify at least the sender An acquisition step of acquiring source identification information;
In wireless communication with the second mobile station apparatus in the wireless communication system, at least a plurality of candidate identification information which are candidates for second transmission source identification information used in a wireless signal for identifying the transmission source are included. A selection step of selecting second transmission source identification information whose inner product with the first transmission source identification information acquired by the acquisition step is smaller than a threshold value from among candidate identification information groups ;
A transmission step of wirelessly transmitting the second transmission source identification information selected in the selection step to the second mobile station device .

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