JP2013046388A - Radio relay device and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio relay device capable of estimating radio wave intensity from a radio base station to suspend a communication function with a radio terminal according to the radio wave field intensity.SOLUTION: A radio relay device includes: a base station controller 24 for acquiring first electric field intensity of a radio wave from a terminal communication unit 32 at a base station communication unit 22, and for acquiring transmission power information of the terminal communication unit 32; and a terminal controller 34. From the base station communication unit 22, the base station controller 24 acquires second electric field intensity of a radio wave from the radio base station at the base station communication unit 22. Based on the first electric field intensity and the transmission power information, the terminal controller 34 calculates a propagation loss, and from the second electric field intensity and the propagation loss, estimates third electric field intensity of the radio wave from the radio base station at the terminal communication unit 32, and suspends the operation of the terminal communication unit 32 if the third electric field intensity is greater than a predetermined threshold.

Description

  The present invention relates to a wireless relay device and a wireless communication method.

  In order for a wireless terminal to communicate with a wireless base station, the wireless terminal needs to be located in a range (service area) where wireless radio waves from the wireless base station can reach. However, there are areas where it is difficult for radio waves to reach because there are many obstacles in urban areas where mountainous areas and high-rise buildings are lined up. In addition, there are many areas (for example, the inside of a building and the basement) where radio waves do not reach from radio base stations installed outdoors. In particular, in a high-speed wireless communication system such as WiMAX (registered trademark) (WiMAX: Worldwide Interoperability for Microwave Access) standardized based on the IEEE standard 802.16e, a frequency band of 2.5 GHz or more is used. Such radio waves in a high frequency band are highly influenced by obstacles because they have a high degree of straightness and a weak property of going around obstacles. In order to cover such a region where radio waves do not reach, a radio relay device (repeater) that relays radio waves between the radio base station and the radio terminal is required.

  In the initial stage of service, radio base stations are often installed only at major bases, and there are many areas where radio waves do not reach.Therefore, by installing radio relay devices in areas where radio waves do not reach, It is preferable to enlarge. However, when the service reaches maturity, the service area that can be covered by the radio base station is expanded by adding the radio base station. As a result, there are cases where a wireless terminal existing in the area of the wireless relay device can communicate with the wireless base station without using an existing wireless relay device.

JP 2007-13763 A

  If the wireless terminal in the wireless relay device area can communicate with the wireless base station without using the wireless relay device, the power consumed by the wireless relay device is useless, so this power consumption can be reduced. preferable.

  For example, as a method of reducing the power consumption of a radio base station, a method of reducing the power consumption by detecting the signal quality of a received signal and suppressing the transmission output when the signal quality is good is known ( Patent Document 1).

  However, since the method described in Patent Document 1 only suppresses the transmission output, it can only reduce the power consumption of the portion directly related to the transmission output by the suppression amount of the transmission output, and the effect of reducing the power consumption is Limited.

  Accordingly, an object of the present invention made in view of such a point is to estimate the electric field strength in the service unit of the radio wave from the radio base station and stop the communication function with the wireless terminal based on the electric field strength. An object of the present invention is to provide a wireless relay device and a wireless communication method.

The invention of the wireless relay device according to the first aspect of achieving the above object is as follows:
A wireless relay device that relays radio waves transmitted and received between a wireless base station and a wireless terminal,
A base station side communication unit that transmits and receives radio waves to and from the wireless base station;
A terminal-side communication unit that transmits and receives radio waves to and from the wireless terminal;
A first electric field strength in the base station side communication unit of radio waves from the terminal side communication unit, and a base station side control unit for obtaining transmission power information of the terminal side communication unit;
A terminal side control unit for controlling the operation of the terminal side communication unit,
The base station side control unit obtains, from the base station side communication unit, a second electric field strength in the base station side communication unit of radio waves from the radio base station,
The terminal side control unit
Propagating from the terminal side communication unit to the base station side communication unit based on the first field strength and transmission power information, acquiring the first field strength and the transmission power information from the base station side control unit Calculate the loss,
From the second electric field strength and the propagation loss, the third electric field strength in the terminal side communication unit of the radio wave from the radio base station is estimated,
When the third electric field strength is greater than a predetermined threshold, the operation of the terminal side communication unit is stopped.

  The invention according to a second aspect is the wireless relay device according to the first aspect, wherein the terminal control unit calculates the propagation loss from a difference between the first electric field strength and the transmission power information, and The third electric field strength is estimated by subtracting the propagation loss from the second electric field strength.

  The invention according to a third aspect is the wireless relay device according to the first or second aspect, wherein the terminal-side control unit automatically calculates the propagation loss at startup, and periodically performs the third The electric field strength is estimated.

  As described above, the solution of the present invention has been described as an apparatus. However, the present invention can be realized as a method, a program, and a storage medium storing the program, which are substantially equivalent to these. It should be understood that these are also included.

For example, the invention of the wireless communication method according to the fourth aspect of realizing the present invention as a method is as follows:
A wireless communication method of a wireless relay device that relays data transmitted and received between a wireless base station and a wireless terminal, the wireless relay device comprising:
A base station side communication unit that transmits and receives radio waves to and from the wireless base station;
A terminal-side communication unit that transmits and receives radio waves with the wireless terminal;
Obtaining a first electric field strength in the base station side communication unit of radio waves from the terminal side communication unit;
Obtaining transmission power information of the terminal-side communication unit;
Calculating a propagation loss from the terminal side communication unit to the base station side communication unit based on the first electric field strength and the transmission power information;
Obtaining a second electric field strength in the base station side communication unit of radio waves from the radio base station;
Estimating a third electric field strength in the terminal-side communication unit of radio waves from the radio base station from the second electric field strength and the propagation loss;
And a step of stopping the operation of the terminal side communication unit when the third electric field strength is larger than a predetermined threshold value.

  According to the present invention, there is provided a radio relay apparatus and a radio communication method capable of estimating an electric field strength in a service unit of radio waves from a radio base station and stopping a communication function with a radio terminal based on the electric field strength. Can be provided.

1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention. It is a functional block diagram which shows schematic structure of the radio relay apparatus which concerns on one Embodiment of this invention. It is a figure which shows the mode of the propagation loss between the service node and donor node of the radio relay apparatus concerning one Embodiment of this invention. It is a flowchart which shows the process which calculates the propagation loss between a service node and a donor node in the radio relay apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the process which determines whether the communication function of a service node is stopped in the radio relay apparatus concerning one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention. The wireless communication system includes a wireless base station, a wireless terminal, and a wireless relay device 10. The wireless relay device 10 relays data transmitted and received between the wireless base station and the wireless terminal.

  FIG. 2 is a functional block diagram showing a schematic configuration of the wireless relay device according to the embodiment of the present invention. The wireless relay device 10 includes a donor node 20 and a service node 30.

  First, functional blocks of the donor node 20 will be described. The donor node 20 includes a base station side communication unit 22 and a base station side control unit 24.

  The base station side communication unit 22 transmits and receives data to and from the radio base station via an antenna. The base station side communication unit 22 receives radio waves from the radio base station, down-converts them, converts them into baseband signals, and outputs them to the terminal side communication unit 32. In addition, the base station side communication unit 22 receives uplink data as a baseband signal from the terminal side communication unit 32, up-converts the converted data into a radio signal, and transmits the radio signal to the radio base station.

  In addition, the base station side communication unit 22 receives radio waves from surrounding radio base stations and its own service node 30 at the time of startup, search, and the like.

  The base station side control unit 24 controls the entire operation of the donor node 20 including the base station side communication unit 22. The base station side control unit 24 is configured as software executed on an arbitrary suitable processor such as a CPU (Central Processing Unit), or a dedicated processor specialized for each process (for example, DSP (Digital Signal Processor)). Can also be configured.

  The base station side control unit 24 acquires the electric field strength Pd at the donor node 20 of the radio base station that is establishing communication from the radio wave from the radio base station received by the base station side communication unit 22.

  The base station side control unit 24 acquires the base station ID of the service node 30 from the terminal side control unit 34 at the time of search or the like. Based on the base station ID, the base station side control unit 24 acquires the electric field strength at the donor node 20 of the radio wave from the service node 30 from the signals received by the base station side communication unit 22. Also, the base station side control unit 24 acquires downlink radio wave information (DCD: Downlink Channel Descriptor) of the service node 30 from the radio waves received by the base station side communication unit 22 based on the base station ID. The downlink radio wave information includes transmission power information of the service node 30 and the like.

  Subsequently, functional blocks of the service node 30 will be described. The service node 30 includes a terminal side communication unit 32 and a terminal side control unit 34.

  The terminal side communication unit 32 transmits / receives data to / from the wireless terminal via the antenna. The terminal-side communication unit 32 receives downlink data as a baseband signal from the base station-side communication unit 22, up-converts it, converts it into a radio signal, and transmits it to the radio terminal. The terminal-side communication unit 32 receives radio waves from the wireless terminals, down-converts them, converts them into baseband signals, and outputs them to the base station-side communication unit 22.

  The terminal side control unit 34 controls the overall operation of the service node 30 including the terminal side communication unit 32. The terminal-side control unit 34 can be configured as software executed on any suitable processor such as a CPU, or can be configured by a dedicated processor (for example, DSP) specialized for each process. In this embodiment, each of the donor node 20 and the service node 30 includes a control unit such that the donor node 20 includes the base station side control unit 24 and the service node 30 includes the terminal side control unit 34. Although described as a configuration, the present invention is not limited to this configuration. For example, the donor node 20 and the service node 30 can be controlled by a single control unit.

  The terminal-side control unit 34 acquires the electric field strength at the donor node 20 of the radio wave from the service node 30 from the base station-side control unit 24 at the time of search or the like. Further, the terminal-side control unit 34 acquires the transmission power information of the service node 30 included in the signal received from the service node 30 by the base station-side communication unit 22 from the base station-side control unit 24.

From the service node 30 to the donor node 20, the terminal-side control unit 34 acquires the electric field strength at the donor node 20 of the radio wave from the service node 30 and the transmission power information of the service node 30 acquired from the base station side control unit 24. The propagation loss L of the path is calculated. The propagation loss is a propagation loss in the path from the service node 30 to the donor node 20 as shown in FIG. The terminal-side control unit 34 calculates the propagation loss L by using the following formula, for example.
Propagation loss L = (transmission power information of service node 30) − (electric field strength at donor node 20 of radio wave from service node 30)

The terminal-side control unit 34 acquires, from the base station-side control unit 24, the electric field strength Pd at the donor node 20 of radio waves from the radio base station that is establishing communication. Based on the propagation loss L and the electric field strength Pd, the terminal-side control unit 34 estimates the electric field strength Ps at the service node 30 of the radio wave from the radio base station. The terminal-side control unit 34 calculates the electric field strength Ps by the following formula, for example.
Electrification strength Ps = field strength Pd−propagation loss L

  When the electric field strength Ps is larger than a predetermined threshold value, the terminal-side control unit 34 determines that the wireless terminal can communicate with the wireless base station without relaying by the wireless relay device 10. Then, the communication function of the service node 30 is stopped by stopping the terminal side communication unit 32. Thereby, the radio relay apparatus 10 can reduce the power consumption that the terminal-side communication unit 32 uses.

  Further, when the field strength Ps is equal to or less than a predetermined threshold value, the terminal-side control unit 34 determines that the wireless terminal cannot communicate with the wireless base station without relaying by the wireless relay device 10, and the terminal The side communication unit 32 is operated as it is, and the communication function of the service node 30 is continued.

  A process in which the wireless relay device 10 calculates a propagation loss between the service node 30 and the donor node 20 will be described with reference to the flowchart of FIG. For example, the wireless relay device 10 automatically executes the process shown in FIG.

  The wireless relay device 10 searches for nearby wireless base stations and the like, and the base station side communication unit 22 receives radio waves from the nearby wireless base stations and its service node 30 (step S101). The base station side control unit 24 acquires the base station ID of the service node 30 from the terminal side control unit 34 (step S102).

  Based on the base station ID of the service node 30, the base station side control unit 24 acquires the electric field strength at the donor node 20 of the radio wave from the service node 30 from the signal received by the base station side communication unit 22. (Step S103). Based on the base station ID, the base station side control unit 24 acquires transmission output information of the service node 30 included in the radio wave from the base station side communication unit 22 (step S104).

  The terminal-side control unit 34 acquires the electric field strength at the donor node 20 of the radio wave from the service node 30 and the transmission power information of the service node 30 from the base station-side control unit 24, and the service node 30 to the donor node 20 Is calculated (step S105).

  Next, a process for determining whether or not the wireless relay device 10 stops the communication function of the service node 30 will be described with reference to the flowchart of FIG. The wireless relay device 10 automatically executes the process shown in FIG. 5 periodically.

  The base station side communication unit 22 receives radio waves from the radio base station (step S201). The base station control unit 24 acquires the electric field strength Pd at the donor node 20 of the wireless base station that is establishing communication from the received radio wave (step S202).

  The terminal-side control unit 34 acquires, from the base station-side control unit 24, the electric field strength Pd at the donor node 20 of the radio wave from the radio base station that is establishing communication. The terminal-side control unit 34 estimates the electric field strength Ps at the service node 30 from the electric field strength Pd and the propagation loss L calculated from the processing according to the flowchart of FIG. 4 (step S203).

  The terminal-side control unit 34 determines whether or not the estimated electric field strength Ps at the service node 30 is at a level at which the wireless terminal can communicate with the wireless base station without relaying by the wireless relay device 10. The electric field strength Ps is compared with a predetermined threshold value (step S204).

  When the electric field strength Ps in the service node 30 is greater than the predetermined threshold, the terminal side control unit 34 stops the terminal side communication unit 32 and stops the communication function of the service node 30 (step S205). When the electric field strength Ps in the service node 30 is equal to or less than the predetermined threshold, the terminal side control unit 34 continues the communication function of the service node 30 without stopping the terminal side communication unit 32 (step S205).

  Thus, according to the present embodiment, the radio relay apparatus 10 stops the communication function of the service node 30 when the radio terminal can communicate with the radio base station without relaying by the radio relay apparatus 10. Therefore, power consumption can be reduced.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, functions included in each member, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. Is possible.

  In the description of the present embodiment, the propagation loss between the service node 30 and the donor node 20 is calculated by receiving the radio wave from the service node 30 at the donor node 20, but the radio wave from the donor node 20 is calculated. The service node 30 may receive and calculate.

DESCRIPTION OF SYMBOLS 10 Radio relay apparatus 20 Donor node 22 Base station side communication part 24 Base station side control part 30 Service node 32 Terminal side communication part 34 Terminal side control part

Claims (4)

A wireless relay device that relays radio waves transmitted and received between a wireless base station and a wireless terminal,
A base station side communication unit that transmits and receives radio waves to and from the wireless base station;
A terminal-side communication unit that transmits and receives radio waves to and from the wireless terminal;
A first electric field strength in the base station side communication unit of radio waves from the terminal side communication unit, and a base station side control unit for obtaining transmission power information of the terminal side communication unit;
A terminal side control unit for controlling the operation of the terminal side communication unit,
The base station side control unit obtains, from the base station side communication unit, a second electric field strength in the base station side communication unit of radio waves from the radio base station,
The terminal side control unit
Propagating from the terminal side communication unit to the base station side communication unit based on the first field strength and transmission power information, acquiring the first field strength and the transmission power information from the base station side control unit Calculate the loss,
From the second electric field strength and the propagation loss, the third electric field strength in the terminal side communication unit of the radio wave from the radio base station is estimated,
The wireless relay device, wherein when the third electric field strength is greater than a predetermined threshold, the operation of the terminal side communication unit is stopped.   2. The radio relay apparatus according to claim 1, wherein the terminal control unit calculates the propagation loss from a difference between the first electric field strength and the transmission power information, and calculates the propagation loss from the second electric field strength. Then, the wireless relay device is characterized by estimating the third electric field strength.   3. The radio relay device according to claim 1, wherein the terminal-side control unit automatically calculates the propagation loss at startup and periodically estimates the third electric field strength. Wireless relay device. A wireless communication method of a wireless relay device that relays data transmitted and received between a wireless base station and a wireless terminal, the wireless relay device comprising:
A base station side communication unit that transmits and receives radio waves to and from the wireless base station;
A terminal-side communication unit that transmits and receives radio waves with the wireless terminal;
Obtaining a first electric field strength in the base station side communication unit of radio waves from the terminal side communication unit;
Obtaining transmission power information of the terminal-side communication unit;
Calculating a propagation loss from the terminal side communication unit to the base station side communication unit based on the first electric field strength and the transmission power information;
Obtaining a second electric field strength in the base station side communication unit of radio waves from the radio base station;
Estimating a third electric field strength in the terminal-side communication unit of radio waves from the radio base station from the second electric field strength and the propagation loss;
And a step of stopping the operation of the terminal side communication unit when the third electric field strength is larger than a predetermined threshold.

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