JP2013066009A - Area extension system, and area extension device and area extension communication method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid congestion associated with increment of a communication amount generated in an upstream from a base station.SOLUTION: In a master unit 21 connected to a base station 11, in the case that a signal is input from an adjacent master unit 23, communication amount information in a constant time period is acquired to determine whether or not input signals from subordinate slave units 3ik exceeds an allowance amount. In the case that the input signals from the subordinate slave units 3ik exceeds the allowance amount, processing of signals is distributed to the adjacent master unit 22, and in the case that the input signals from the subordinate slave units 3ik do not exceed the allowance amount, whether or not signals from the adjacent master unit 23 exceeds the allowance amount is determined. In the case that the signals from the master unit exceeds the allowance amount, processing of signals is distributed to the adjacent master unit 22, and in the case that the signals do not exceed the allowance amount, the signals are synthesized and transmitted to the base station 11.

Description

  Embodiments described herein relate generally to an area expansion system that avoids congestion associated with an increase in communication volume, an area expansion apparatus and an area expansion communication method used in the system.

  Generally, a wireless communication system includes a plurality of base stations that form an area for wireless communication with a mobile terminal. In these base stations, an area expansion device for expanding the communication area of the base station is often installed. This area expansion device enables a signal transmitted and received by an antenna provided in a base station to be transmitted and received in a wider area, and includes a parent device and a plurality of child devices connected to the parent device. The master unit is connected to the base station, and the plurality of slave units are connected to the master unit and are arranged at arbitrary locations. The master unit receives a radio wave reception signal from each slave unit and transmits it to the base station, and receives a transmission signal from the base station and wirelessly distributes it to each slave unit. By using this area expansion device, it is possible to expand the communication area covered by the base station and reduce the dead zone of radio waves.

  However, since the area expansion device using the parent device and the child device transmits and receives signals transmitted and received in the base station in a wider communication area, the amount of communication allowed in the expanded area is the same as that of the base station. It remains as it is. If the amount of communication in the area exceeds the allowable amount of the base station, congestion will occur frequently in the network layer higher than the base station, thereby making it difficult to establish communication.

JP 2011-49784 A

  As described above, in the conventional area expansion device, when the communication amount in the base station jurisdiction area extended by the slave unit exceeds the allowable amount of the base station, congestion frequently occurs in the network layer higher than the base station. It becomes difficult to connect communication.

  Therefore, the present embodiment has been made in view of the above, and avoids congestion at a higher level than the base station even when the communication amount in the base station jurisdiction area extended by the slave unit exceeds the allowable amount of the base station. It is an object of the present invention to provide an area expansion system, an area expansion device, and an area expansion communication method.

  In order to achieve the above object, an area expansion system according to the present embodiment is an area expansion system including a plurality of base stations that wirelessly communicate with mobile terminals, and a base unit connected to the base station and the parent In an area expansion system that expands the wireless communication area of each of the base stations using a plurality of area expansion devices including a plurality of slave devices connected to the device, a connection for connecting the parent devices between the area expansion devices And a communication amount based on a reception level of each of the plurality of slave units, and compared with a communication allowable amount. If the communication allowable amount is not satisfied, the reception is performed. Send destination to base station connected to base unit, and select destination to send to base unit of other area expansion device connected by the connection means when the communication allowance is exceeded The transmission destination selection means of the area expansion device that has received a received signal from the area expansion device that exceeds the communication allowance exceeds the communication allowance of the base station to which the area expansion device is connected In this mode, the reception signal from the switching source area expansion device is transmitted to an area expansion device different from the switching source area expansion device.

  Further, the area expansion device of the area expansion system according to the present embodiment is used in an area expansion system including a plurality of base stations that wirelessly communicate with mobile terminals, and is connected to the base unit connected to the base station and the base unit. An area expansion device for expanding a wireless communication area of the base station, wherein the parent device is connected to a parent device of another area expansion device; The amount of communication based on the reception level of each of the slave units is detected and compared with the communication allowable amount. If the communication allowable amount is not satisfied, the received signal is sent to the base station to which the base unit is connected, A destination selection means for sending to a master unit of another area expansion device connected by the connection means when the communication allowable amount is exceeded, and receiving a reception signal from the area expansion device exceeding the communication allowable amount If When the destination selection means exceeds the communication allowable capacity of the base station to which the area expansion device is connected, the destination selection means sends the received signal from the area expansion device of the switching source to an area expansion device different from the area expansion device of the switching source. It is assumed that it is sent out.

  The area expansion communication method of the area expansion system according to the present embodiment is an area expansion system including a plurality of base stations that wirelessly communicate with mobile terminals, and includes a base unit connected to the base station and the base unit Applied to an area expansion system that expands the wireless communication area of each of the plurality of base stations using an area expansion device comprising a plurality of slave devices connected, and connects the parent devices between the area expansion devices, In each of the area expansion devices, the communication amount based on the reception level of each of the plurality of slave units is detected and compared with the communication allowable amount. If the communication allowable amount is not satisfied, the reception signal is connected to the parent unit. Area expansion device that is sent to a base station and sent to the base unit of another area expansion device connected by the connection means when the communication allowable amount is exceeded, and exceeds the communication allowable amount When the switching destination area expansion device that has received the received signal exceeds the allowable communication capacity of the base station to which the area expansion device is connected, the switching to the area expansion device different from the switching area expansion device is performed. The reception signal from the original area expansion device is transmitted.

It is a conceptual diagram which shows the structure of the area expansion system which concerns on this embodiment. It is a block diagram which shows the specific structure of the area expansion system shown in FIG. FIG. 3 is a block diagram showing a specific configuration of the parent device shown in FIG. 2. 4 is a flowchart showing the flow of processing when a signal is input from a slave unit in the master unit shown in FIG. 3. 4 is a flowchart showing the flow of processing when a signal is input from an adjacent parent device in the parent device shown in FIG. 3.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a configuration of an area expansion system according to the present embodiment. In this area expansion system, an area expansion device including a base unit and a plurality of slave units is connected to each of a plurality of base stations provided in an area expansion system in which a mobile terminal and a base station (BTS: Base Transceiver Station) communicate wirelessly. The In each area expansion device, as shown in FIG. 1, a master unit is connected to a base station, and a plurality of slave units connected to the master unit are arranged at arbitrary locations away from the base station. A reception signal received by the mobile station is transmitted to the base station through the master unit, and a transmission signal from the base station is distributed to each slave unit through the master unit and wirelessly transmitted from each slave unit to the communication area.

  FIG. 2 is a block diagram showing a specific configuration of the area expansion system shown in FIG. Here, an area expansion device composed of a base unit 2i and a slave unit 3ik (k is 1 to 3) is connected to a base station (hereinafter referred to as BTS) 1i (i is 1 to 3). Is shown. The parent device 2i has a plurality (three in this case) of communication ports #mn for connecting the child device 3ik, an external input port EX-in for inputting a signal from another parent device, and another parent device. Is provided with an external output port EX-out for outputting a signal. In the figure, a communication port for connecting the child device 3ik is denoted by #mn. m is the number of the parent device 2i on which the communication port is mounted (m = i), and n is the communication port identification number (n is 1 to 3). The external output ports EX-out of the parent devices 21, 22, and 23 are cyclically connected to the external input port EX-in of the adjacent parent device.

  FIG. 3 is a block diagram showing a specific configuration of base unit 21 shown in FIG. Since the other master units 22 and 23 have the same configuration as the master unit 21, the description thereof is omitted here.

  In FIG. 3, the base unit 21 includes a first signal conversion unit 211 that converts received signals by optical signals supplied from the slave units 311, 312, and 313 to the communication ports # 11, # 12, and # 13 into electrical signals. A connection interface unit (hereinafter simply referred to as a connection unit) 212 for receiving a reception signal supplied from another parent device through the external input port EX-in, and a reception signal to the other parent device through the external output port EX-out. And a connection unit 213 for sending out the message. Note that communication between the parent device 21 and the child devices 311, 312, and 313 may be performed using electrical signals instead of optical signals. Here, in order to describe the uplink signal, the connection units 212 and 213 are described as the external input port EX-in and the external output port EX-out, but the external input port EX-in and the external output port EX- “out” means an external output and an external input in the case of handling as an upstream signal, and the transmission direction of the signal passing through the connection units 212 and 213 is reversed for the downstream signal.

  The master device 21 includes a determination switching unit 214, a signal processing unit 215, and a second signal conversion unit 216. The determination switching unit 214 obtains communication amount information within a predetermined time for each of the received signals supplied to the first signal conversion unit 211 and the connection unit 212, and the communication amount of each communication port # 11, # 12, # 13. Each of which exceeds a predetermined allowable amount (allocated based on the allowable amount of the BTS 11), and when the signal input does not exceed the allowable amount (NO), the signal is derived to the signal processing unit 215. If the allowable amount is exceeded (YES), the signal is derived to the connection unit 213. The signal processing unit 215 simply synthesizes reception signals from each child device or other parent device derived from the determination switching unit 214. The second signal conversion unit 216 converts the reception signal processed by the signal processing unit 215 into an RF signal and transmits the RF signal to the BTS 11. In the signal processing unit 215, when the signals are combined, if the signal is a digital signal, the signal is combined using an adder, and if the signal is an analog signal, the signal is combined using a combiner.

  Here, the determination criteria of the determination switching unit 214 will be described. In a general area expansion system, when a BTS performs radio communication with a mobile terminal, the BTS monitors the reception level (reception power) of a received signal so that the reception level becomes an appropriate level. Instruct the transmission level (transmission power). For this reason, the area expansion apparatus can grasp to some extent the number of mobile terminals that perform wireless communication via the area expansion apparatus from the reception level received by each of its own slave stations. That is, since the communication amount can be estimated based on the reception level, the determination is performed based on the reception level. However, in the determination based only on the reception level, the accuracy of the determination may be low, for example, the mobile terminal cannot assume the reception level before communication with the BTS is established. For this reason, the degree of change in the reception level within a certain time is also included in the criterion.

  In the above-described embodiment, the determination switching unit 214 acquires the communication amount information within a predetermined time for each of the received signals supplied to the first signal conversion unit 211 and the connection unit 212. The acquisition of the quantity information may be performed by the slave units 311, 312, and 313 and transmitted together with the received signal. Further, instead of the determination processing unit 214, an information acquisition unit may be installed in the parent device 21 to acquire the traffic information. Alternatively, the communication amount may be measured on the slave unit side, and the obtained communication amount information may be notified to the parent device.

  The operation of the area expansion system having the above configuration will be described below.

  First, in the area expansion system according to the above embodiment, a plurality of parent devices 2i are connected to each other, and even if the received signals from the child devices 311, 312, and 313 exceed the allowable amount, The processing of the received signal can be distributed to 23.

  For example, when the reception level of the child device 313 connected to the parent device 21 increases but exceeds the allowable amount, the reception signal of the child device 313 is transmitted to the parent device 22 instead of the BTS 11 and received from the parent device 22 to the BTS 12. Transmit the signal. If the input communication volume from the slave units 321, 322, 323 is too close to the allowable amount of the BTS 12 in the master unit 22, the received signal from the master unit 21 is transmitted to the master unit 23, and the BTS 13 Transmit the received signal to. At this time, the base unit 22 does not process the received signal and transmits the received signal transparently.

  On the other hand, when the area expansion system as described above is small and communication is congested in any of the parent device 2i and the child device 3ik, there is a situation in which signal path switching to the adjacent parent device 2i is repeatedly executed. Occur. In order to prevent this, when route switching is performed, a method is provided in which, apart from the main signal, hop count information (information about how many times the master unit 2i has been passed) is given and transmitted to the adjacent master unit 2i. take. This information is incremented by 1 every time it passes through EX-out, and after setting the upper limit, a signal that reaches the upper limit is terminated and rejected.

  Next, the processing flow of the area expansion system configured as described above will be described with reference to FIGS.

  First, FIG. 4 is a flowchart showing the flow of processing when a reception signal from the slave unit is input in the master unit 21 shown in FIG. Here, as an example, it is assumed that the communication amount of the child device 313 increases, and the reception level of the signal is a constant value (for example, the average value of the total reception level is −40 dBm) as the allowable amount of communication amount of the child device 313. The above description is based on the assumption that the change within a certain time is a certain value (10 dB) or more. That is, as determination materials of the allowable amount of communication amount of the slave unit 313, the allowable value of the signal reception level (hereinafter referred to as the level allowable value) and the allowable value of the change amount of the signal reception level (hereinafter referred to as the amount of change). To be an acceptable value).

  First, input of a reception signal from the slave unit 313 is waited (step S11). When a reception signal is input, it is determined whether the reception level of the reception signal is equal to or higher than a certain value (step S12). . Although the reception level is acquired on the parent device side here, the reception level information may be acquired on the child device side and notified to the parent device.

  Here, in step S12, when the reception level of the received signal becomes a certain value (level allowable value) or more, the transmission destination of the received signal is switched to the adjacent base unit 22 (step S13). Thereafter, the state is maintained for a certain time (step S14), and the latest reception level change information within the certain time is acquired (step S15). It is determined whether or not the reception level change is equal to or greater than a predetermined value (change amount allowable value) (step S16). If the reception level change is equal to or greater than the predetermined value, the process returns to step S14 and the above operation is repeated.

  In step S12, if the reception level of the reception signal does not exceed a certain value, or if the change in the reception level of the reception signal does not exceed a certain value in step S16, the reception signal is transmitted to the signal processing unit 215 and received. The signals are simply combined, and the combined received signal is transmitted to the BTS 11 (step S17). And it waits until receiving level information within the next fixed time is acquired (step S18).

  FIG. 5 is a flowchart showing a processing flow when a signal is input from the adjacent parent device 23 in the parent device 21 shown in FIG.

  First, it waits for a signal input from the adjacent parent device 23 (step S21). When a signal is input from the parent device 23, the communication amount of the input signal from the slave devices 311, 312, and 313 under the control. It is determined whether or not exceeds the allowable amount (step S22). At this time, if the signals input from the slave units 311, 312, and 313 exceed the allowable amount, the transmission destination of the signal from the master unit 23 is switched to the adjacent master unit 22 (step S23), and the process returns to step S21. Repeat the above operation. Here, if the signals input from the child devices 311, 312, 313 do not exceed the allowable amount, it is determined whether or not the received signal input from the adjacent parent device 23 is a certain value (allowable value) or more (step). S24). If the signal exceeds the allowable amount, the signal transmission destination is switched to the adjacent base unit 22 (step S25), the state is maintained for a certain time (step S26), and the reception level change information within the latest certain time is stored. It is acquired (step S27), and it is determined whether or not the change in the reception level is equal to or greater than a certain value (a bell tolerance) (step S28). When the reception level change exceeds a certain value, the process returns to step S26 and the above operation is repeated.

  In steps S22 and S28, if the value does not exceed a certain value, the received signal is transmitted to the signal processing unit 215, the received signal is simply combined, and the combined received signal is transmitted to the BTS 11 (step S29). And it waits until the reception level information within the next fixed time is acquired (step S30).

  That is, in the area expansion system configured as described above, when the received signal of the slave station 313 under the parent device 21 exceeds the allowable amount, the signal path is switched from the parent device 21 to the parent device 22. Thus, a signal from the slave unit 313 under the BTS 11 is transmitted from the master unit 21 to the BTS 12 through the master unit 22, and is sent from the BTS 12 to the host device.

  In the above state, the BTS 12 and the host apparatus determine that the handset 313 has handed over from the BTS 11 to the BTS 12 because the signal path of the handset 313 under the BTS 11 has been switched to the BTS 12, and Deliver the signal to the BTS 12. At this time, the BTS 12 transmits a downstream signal to the subordinate base unit 22, but the transmission destination of the base unit 22 is transmitted to the subordinate subordinate units 321, 322, 323 through the subordinate subordinate units 321, 322, 323. At the same time, a downstream signal is sent to and sent to the adjacent base unit 21 connected by the switching, and transmitted to all the handset units 311, 312, and 313 through the base unit 21. This makes it possible to transmit a downlink signal to mobile terminals in the area of handset 313.

  Note that when determining the allowable amount of traffic, the allowable amount is determined separately for the slave device under the parent device and the slave device under the adjacent parent device. It is possible for the parent device that determines whether or not to determine any child device as a child device under its control without distinguishing between them.

  In addition, when a signal from a slave unit under the control of an adjacent master unit is input to the master unit, the allowable communication amount for the slave unit under the master unit is set to You may make it a different value from the case where the signal from a subunit | mobile_unit is not input.

  As described above, in the area expansion system according to the above-described embodiment, the reception level information within a certain time of the input signal is acquired, the reception signal from the child device 3ik, and the reception signal transmitted from the adjacent parent device 2i. Is determined to exceed the allowable amount of the base station 1i. If the received signal exceeds the allowable amount of the base station 1i, the processing of the received signal is distributed to the other base unit 2i. For this reason, the received signals are not concentrated on one base station 1i, and congestion can be avoided.

  In addition, in order to detect traffic information within a certain period of time, it is basically necessary to know how many users are communicating and how much traffic by looking at the contents of the received signal. In the present embodiment, this processing takes time. However, in this embodiment, the received signal is simply distributed and simply combined by the master unit 2i, and the communication amount is simply determined based on the reception level. It can also be expected that this effort is kept to a minimum and an increase in processing time is suppressed to a minimum.

  Further, in the description of the above embodiment, as the allowable amount of communication, the average value of the signal reception total level is -40 dBm or more for the level allowable value, and the change within a certain time is 10 dB or more for the change allowable value. Although the case has been exemplified, there is no change within a certain time, but a criterion for determining the allowable amount of communication may be provided such that the average value of the total received signal level is, for example, −30 dBm or more.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1i ... Base station (BTS), 2i ... Base unit, 3k ... Slave unit, #mn, EX-in, EX-out ... Communication port, 211 ... First signal conversion unit, 212, 213 ... Connection unit, 214 ... Determination processing unit, 215... Signal processing unit, 216... Second signal conversion unit.

Claims (12)

An area expansion system including a plurality of base stations that communicate wirelessly with a mobile terminal, using a plurality of area expansion apparatuses including a parent device connected to the base station and a plurality of child devices connected to the parent device In the area expansion system for expanding the radio communication area of each base station,
Connection means for connecting the master units between the area expansion devices;
Provided in each of the plurality of area expansion devices, detecting a communication amount based on a reception level of each of the plurality of slave units and comparing the detected communication amount with a communication allowable amount; Sending destination selection means for sending to a base station to which the base unit is connected and sending to the base unit of another area expansion device connected by the connection means when the communication allowance is exceeded. And an area expansion system.   The transmission destination selection means of the area expansion device that has received the received signal from the area expansion device that exceeds the allowable communication amount, if the communication destination of the base station to which the area expansion device is connected exceeds the communication allowable amount, 2. The area expansion system according to claim 1, wherein a reception signal from the switching area expansion device is transmitted to an area expansion device different from the area expansion device.   2. The area expansion system according to claim 1, wherein the transmission destination selection unit determines that the communication amount exceeds an allowable amount when at least an average value of the reception levels is a certain value or more.   The transmission destination selection unit determines that the communication amount exceeds an allowable amount when an average value of the reception levels is a certain value or more and a change in the reception level is a certain value or more. The area expansion system according to 1. Used in an area expansion system including a plurality of base stations that communicate wirelessly with a mobile terminal, comprising a master unit connected to the base station and a plurality of slave units connected to the master unit, An area expansion device for expanding a communication area,
The base unit is
Connection means for connecting to the master unit of another area expansion device;
A communication amount based on the reception level of each of the plurality of slave units is detected and compared with a communication allowable amount. If the communication allowable amount is not satisfied, the received signal is transmitted to a base station to which the parent unit is connected. An area expansion apparatus for an area expansion system, comprising: a destination selection means for transmitting to a master unit of another area expansion apparatus connected by the connection means when the communication allowable amount is exceeded.   When a reception signal is received from an area expansion device that exceeds the allowable communication amount, the transmission destination selection means, if the communication amount of the base station to which the area expansion device is connected exceeds the communication allowable amount, 6. The area expansion apparatus of an area expansion system according to claim 5, wherein a reception signal from the switching area expansion apparatus is transmitted to an area expansion apparatus different from the apparatus.   6. The area expansion apparatus for an area expansion system according to claim 5, wherein the transmission destination selection unit determines that the communication amount exceeds an allowable amount when at least an average value of the reception levels is a certain value or more.   The transmission destination selection unit determines that the communication amount exceeds an allowable amount when an average value of the reception levels is a certain value or more and a change in the reception level is a certain value or more. 5. An area expansion device of the area expansion system according to 5. An area expansion system comprising a plurality of base stations that communicate wirelessly with a mobile terminal, using an area expansion device comprising a master unit connected to the base station and a plurality of slave units connected to the master unit Applied to an area expansion system that expands the wireless communication area of each of a plurality of base stations,
Connect the base units between the area expansion devices,
In each of the area expansion devices, the communication amount based on the reception level of each of the plurality of slave units is detected and compared with the communication allowable amount. If the communication allowable amount is not satisfied, the reception signal is connected to the parent unit. An area expansion communication method for an area expansion system, wherein the area expansion communication method transmits to a previous base station and transmits to a base unit of another area expansion apparatus connected by the connection means when the communication allowable amount is exceeded.   When the switching destination area expansion device that has received a received signal from an area expansion device that exceeds the allowable communication amount exceeds the communication allowable amount of the base station to which the area expansion device is connected, the switching source area expansion device 10. The area expansion communication method of the area expansion system according to claim 9, wherein a reception signal from the switching area expansion device is transmitted to an area expansion device different from the area expansion device.   10. The area expansion communication of the area expansion system according to claim 9, wherein the destination selection process determines that the communication amount exceeds an allowable amount at least when an average value of the reception levels is a certain value or more. Method.   The destination selection processing is characterized in that the communication amount is determined to exceed an allowable amount when an average value of the reception level is a certain value or more and a change in the reception level is a certain value or more. Item 10. An area expansion communication method for an area expansion system according to Item 9.

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