JP2007124300A - Wireless communication method, wireless base station device and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication method capable of flexibly distributing traffic loads corresponding to not only wireless traffic but also network traffic and shortening the communication impossible state of the communication terminal of a fault base station area when a fault occurs. <P>SOLUTION: A network I/F 1 periodically measures a network traffic amount. When the measured network traffic amount increases and becomes larger than a threshold, a control part 4 refers to a transmission output level correspondence table stored in a storage part 5 by output from the network I/F 1 and issues an instruction to a wireless I/F 2 to lower a transmission output level, and the wireless I/F 2 lowers the transmission output level. Also, to surrounding base stations, signals indicating the increase of the transmission output level so as to compensate an area range turned out of the communication area of the present station due to the decline of the transmission output level are transmitted simultaneously. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

 The present invention relates to a transmission power control technique for a wireless communication system, and relates to a wireless communication method, a wireless base station apparatus, and a wireless communication system used in a wireless base station apparatus connected to a network.

 In a wireless communication system connected to a network, the communication throughput on the wireless terminal side is also affected by the performance capability and communication traffic of the wireless base station. Regarding the load distribution method for communication traffic in the radio base station, the base stations exchange their transmission rates with each other, and further calculate and compare the temporary transmission rate when the terminal is handed over using the value, There has been proposed a method of using a criterion for invoking handover on a terminal (see, for example, Patent Document 1).

Also, if communication with the server that controls the base station becomes impossible due to some kind of failure, a method may be considered in which the server detects this and transmits a message to that effect to other base stations to control the base station. ing. An instruction to increase downlink transmission power is given to a radio base station that manages a cell adjacent to the cell of the base station in which the failure has occurred, and the cell radius is increased by increasing the cell radius. For example, refer to Patent Document 2 or by transmitting a power-off command from a base station in the vicinity of a base station in which a fault has occurred to a base station in which a fault has occurred to There was a way to turn off. (For example, see Patent Document 3)
JP 2004-297621 A JP 2003-078938 A JP-A-11-146033

 However, the conventional technology focuses on the radio unit, such as predicting and using a variable modulation scheme in communication between a radio base station and a radio terminal for calculation. However, the radio base station has two interfaces on the radio side and the network line side, and the processing capacity of the base station is limited not only by the communication traffic and performance on the radio side, but also by the communication traffic and performance on the network line side. Receive. Also, in reality, the communication traffic on the network line side is expected to fluctuate greatly, and even if the communication state on the wireless side is good, if the network side is not good, the processing capacity at the base station will be reduced, and the system will There was a problem that communication as a whole became unsatisfactory and the traffic load was not necessarily distributed flexibly according to network traffic.

 Further, according to the conventional technology, a failure is detected when communication between the server and the wireless base station is interrupted on the network line side, and the network line side notifies the base station to that effect. Also, even if the failure of the base station is a failure on the network line side of a network device or the like, stop the communication of the base station according to the failure detected by itself, or other base stations in the vicinity The communication of the base station was stopped by the power off command via radio from. However, in the case of failure notification using the network line side, failure notification takes time depending on the network route, and transmission control of other base stations in the vicinity to cover the area of the failed base station is also delayed. As a result, there is a problem that a power loss of the transmission output from the failed base station occurs, and the communication disabled state of the communication terminal in the failed base station area becomes longer.

 The present invention has been made in order to solve such a problem. The present invention performs flexible traffic load distribution according to not only wireless traffic but also network traffic, and shortens the communication disabled state of communication terminals in the failed base station area when a failure occurs. It is an object of the present invention to provide a radio communication method, a radio base station apparatus, and a radio communication system that can be used.

 The present invention has been made to solve the above problems, and the invention according to claim 1 is a wireless communication method in a wireless base station apparatus that is connected to a network and performs wireless communication with a wireless terminal. The first step of detecting the communication state on the network side, the second step of controlling the wireless transmission output based on the detection result of the first step, and the wireless transmission output in the second step A third step of transmitting information necessary for increasing the radio transmission output to the other radio base station apparatus when lowering or changing to zero. A wireless communication method is characterized.

 In the invention according to claim 2, the communication state is communication traffic or a reception level, and the second step is when the communication traffic or reception level detected in the first step is zero, The wireless communication method according to claim 1, wherein the wireless transmission output of the local station is set to zero.

 According to a third aspect of the present invention, the communication state is communication traffic or a reception level, and the second step is a threshold in which the communication traffic or reception level detected in the first step is preset. The wireless communication method according to claim 1, wherein the wireless transmission output of the local station is lowered when the value is greater than or equal to the threshold value.

 According to a fourth aspect of the present invention, in a radio base station apparatus that is connected to a network and performs radio communication with a radio communication terminal, a detection means that detects a communication state on the network side, and the detection And a transmission output control unit that controls a radio transmission output based on a detection result in the unit.

 The invention according to claim 5 is necessary for the other radio base station apparatus to increase the radio transmission output toward the other radio base station apparatus when the transmission output control means lowers the radio transmission output. 5. The radio base station apparatus according to claim 4, further comprising signal transmission means for transmitting various information.

 According to a sixth aspect of the present invention, in the wireless communication system comprising a wireless communication terminal and a wireless base station apparatus connected to a network and performing wireless communication with the wireless terminal, the wireless base station apparatus Detecting means for detecting the communication state on the network side, transmission output control means for controlling the wireless transmission output based on the detection result in the detecting means, and when the transmission output control means lowers the wireless transmission output, A wireless communication system comprising: a signal transmission unit configured to transmit information necessary for the other wireless base station device to increase a wireless transmission output toward the wireless base station device.

 According to the first aspect of the present invention, flexible traffic load distribution according to not only wireless traffic but also network traffic can be performed.

 According to the invention of claim 2, it is possible to shorten the communication disabled state of the communication terminal in the failed base station area when a network line failure occurs.

 According to the invention of claim 3, when the communication traffic increases by a certain amount or more, the traffic load can be distributed smoothly.

 According to the invention of claim 5, it is possible to provide a radio base station apparatus that realizes flexible traffic load distribution according to network traffic.

 According to the invention of claim 6, it is possible to provide a radio communication system that realizes flexible traffic load distribution with a system configuration of a radio base station apparatus and a radio terminal connected to a network.

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a radio base station apparatus according to this embodiment. The radio base station apparatus in FIG. 1 is connected to a network I / F (Interface) 1 (corresponding to a detecting means) connected to a network and a network I / F 1 to perform transmission output control and transmission / reception mode control. Wireless I / F2 (corresponding to signal transmission means), antenna 3 connected to wireless I / F2, and control unit 4 for controlling network I / F1 and wireless I / F2 (corresponding to transmission output control means) And a storage unit 5 in which a transmission output level correspondence table used for transmission output control is stored.

 FIG. 2 is an example of network I / F statistical information used in this embodiment. Here, an example of statistical information by MIB (Management Information Base) 2 is shown. It is assumed that the network I / F 1 has a function for collecting statistical information. As a measure for measuring the amount of network traffic on the network line side of the radio base station, the sum of ifInOctets (number of received octets) and ifOutOctets (number of transmitted octets) is used. The network I / F 1 always recognizes the amount of network traffic transmitted and received within a certain time.

 FIG. 3 is an example of a transmission output level correspondence table stored in the storage unit 5. Here, the network traffic amount is divided into five stages according to the degree of congestion, and the transmission output level of the radio base station is associated with each stage. A predetermined value based on experience or calculation is assigned as a threshold value for dividing each stage. In the stage where the amount of network traffic between threshold 0 and threshold 1 is the smallest, the transmission output level corresponds to the strongest level 1, and in the range of threshold 1 to threshold 2, the transmission output level corresponds to level 2. Set so that the transmission output level decreases as the amount of network traffic increases.

 When there is no network traffic, it is considered that there is an abnormality in the network I / F 1, so it is not included here, and the minimum network traffic during normal operation is set as a threshold value 0. In the present embodiment, five stages are provided as the network traffic volume stages, but the present invention is not limited to this.

 FIG. 4 is a schematic diagram showing an overall configuration of a radio system including the radio base station apparatus according to the present embodiment. FIG. 4 includes radio base stations B1 to B5, routes R1 to R5 that connect the radio base stations B1 to B5 and the network, and a radio communication terminal C1 in the area of the radio base station B4. The circle surrounding each of the radio base stations B1 to B5 schematically represents the communication area covered by each of the radio base stations B1 to B5. The radio base stations B1 to B5 are connected to a network through paths R1 to R5 and perform data communication in the upward and downward directions. The routes R1 to R5 may include a plurality of network devices such as routers and switches.

 Next, the operation of this embodiment will be described. Here, a case will be described in which the network traffic amount of the radio communication base station B4 increases to reach the threshold value and the transmission output level is lowered as shown in FIG. First, the network I / F 1 of the radio communication base station B4 regularly measures the amount of network traffic. Assume that the measured network traffic volume increases and exceeds the threshold.

 Upon receiving the network traffic volume output from the network I / F 1, the control unit 4 refers to the transmission output level correspondence table stored in the storage unit 5, instructs the wireless I / F 2 to lower the transmission output level, and / F2 lowers the transmission output level. At the same time, for the surrounding radio base stations B3 and B5, the transmission output level of the radio base stations B3 and B5 is increased in order to compensate for the area range outside the communication area of the radio base station B4 due to the decrease in the transmission output level. Send a signal to that effect.

 The transmission of a signal for increasing the transmission output to the radio base stations B3 and B5 by the radio base station B4 is performed as follows, for example. That is, in the wireless base station B4, when the network I / F1 measures the amount of network traffic and the measured amount of network traffic increases and becomes larger than the threshold value, the control unit 4 sets the network I / F1. In contrast, control is performed so that communication with the network is interrupted, and further, the wireless I / F 2 is controlled so that the wireless I / F 2 can transmit a signal even at the reception timing of the signal from the wireless communication terminal. To change the transmission / reception mode.

 If there are factors that prevent the surrounding wireless base stations B3 and B5 from increasing the transmission output any more, or if the surrounding wireless base stations B3 and B5 have a large amount of network traffic and cannot handle more network traffic. The transmission output level is not changed. On the contrary, if the network traffic amount of the radio base station B4 decreases and reaches the threshold value, the radio base station B4 increases the transmission output level and requests the surrounding radio base stations B3 and B5 to recover the cover area. And the surrounding radio base stations B3 and B5 that have increased the transmission output level perform processing for restoring the transmission output level.

 In the radio base station apparatus of this embodiment, it is assumed that a failure has occurred in the network line side portion of the radio base station B4 as shown in FIG. When the control unit 4 detects that a failure has occurred in the part of the wireless base station B4 on the network line side, the wireless I / F 2 is directed to the surrounding wireless base stations B3 and B5 via the antenna by an instruction from the control unit 4 Send a signal that a failure has occurred.

 In this case, the radio base station B4 transmits a signal for increasing the transmission output to the radio base stations B3 and B5, for example, as follows. That is, when the control unit 4 detects that a failure has occurred on the network line side, the radio base station B4 causes the control unit 4 to interrupt the network I / F 1 from communicating with the network. In addition, the transmission / reception mode is changed so that the wireless I / F 2 can transmit the signal even at the reception timing of the signal from the wireless communication terminal.

 After the surrounding radio base stations B3 and B5 receive the notification of the occurrence of the failure, if the failed radio base station B4 is an adjacent radio base station, the transmission output level is changed, and the faulty radio base station B4 Raise the transmission output level to complement the communication area. After the communication area is complemented, the control unit 4 of the failed radio base station B4 promptly stops the output by instructing the radio I / F 2 to stop the transmission output, and the radio terminal in its own communication area To prevent miscommunication.

 Similarly, when the faulty radio base station B4 is restored through work such as repair, the restoration notification is promptly sent to the surrounding radio base stations B3 and B5. Note that the restoration notification in this case may be performed by wireless communication or through a network side line.

 The present invention relates to a transmission power control technique for a radio communication system, and is suitable for use in a radio communication method used in a radio base station apparatus connected to a network.

It is a block diagram which shows the structure of the wireless base station apparatus concerning embodiment of this invention. It is a figure which shows the example of network I / F statistical information used with the radio base station apparatus concerning embodiment of this invention. It is a figure which shows the example of the transmission output level corresponding table memorize | stored in the memory | storage part 5 of the wireless base station apparatus concerning embodiment of this invention. It is a schematic diagram which shows the whole structure of the radio | wireless communication network containing the radio base station apparatus concerning embodiment of this invention. It is a figure when the communication traffic of wireless base station apparatus B4 increases in a wireless communication network. FIG. 10 is a diagram when a line failure occurs in the network line of the wireless base station device B4 in the wireless communication network.

Explanation of symbols

1 ... Network I / F (detection means)
2 ... Wireless I / F (signal transmission means)
3 ... Antenna 4 ... Control unit (transmission output control means)
DESCRIPTION OF SYMBOLS 5 ... Memory | storage part B1-B5 ... Wireless base station apparatus C1 ... Wireless terminal

Claims (6)

In a wireless communication method in a wireless base station device that is connected to a network and performs wireless communication with a wireless terminal,
A first step of detecting a communication state on the network side;
A second step of controlling the radio transmission output based on the detection result of the first step;
When the radio transmission output is decreased or changed to zero in the second step, information necessary for the other radio base station apparatus to increase the radio transmission output is transmitted to another radio base station apparatus. A wireless communication method comprising: a third step. The communication state is communication traffic or reception level,
2. The wireless communication according to claim 1, wherein in the second step, when the communication traffic or the reception level detected in the first step is zero, the wireless transmission output of the own station is set to zero. Method. The communication state is communication traffic or reception level,
The second step is characterized in that when the communication traffic or reception level detected in the first step is equal to or higher than a preset threshold value or larger than a threshold value, the radio transmission output of the own station is lowered. Item 2. A wireless communication method according to Item 1. In a radio base station apparatus that is connected to a network and performs radio communication with a radio communication terminal,
Detecting means for detecting a communication state on the network side;
A transmission output control means for controlling a wireless transmission output based on a detection result in the detection means;
A radio base station apparatus comprising:  When the transmission output control means lowers the radio transmission output, further provided is a signal transmission means for transmitting information necessary for the other radio base station apparatus to increase the radio transmission output toward the other radio base station apparatus. The radio base station apparatus according to claim 4, wherein In a wireless communication system comprising a wireless communication terminal and a wireless base station device connected to a network and performing wireless communication with the wireless terminal,
The wireless base station device
Detecting means for detecting a communication state on the network side;
A transmission output control means for controlling a wireless transmission output based on a detection result in the detection means;
When the transmission output control means lowers the radio transmission output, signal transmission means for transmitting information necessary for the other radio base station apparatus to increase the radio transmission output toward the other radio base station apparatus;
A wireless communication system characterized by comprising:

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