JP2009077224A - Radio communications equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain high-reliability radio communication by avoiding interference due to the arrival of disturbance wave. <P>SOLUTION: A control part 23 of radio communications equipment 1-1 detects received field intensity from radio signals received by each of a plurality of radio-frequency channels, respectively, and stores the detected received field intensity of each radio-frequency channel in an interference wave table 241 as interference wave levels by means of an interference wave determining part 25. The control part 23 sets priority in an order from a radio-frequency channel whose received field intensity is equal to or higher than a predetermined threshold for receiving desired wave, and whose received field intensity is low, as the candidates for channels for communication by means of a frequency selection part 26 to create a priority table 242. The control part 23 selects a radio-frequency channel with high priority from among the plurality of radio-frequency channels in accordance with the priority table 242, and establishes a communication path with radio communications equipment at a partner by using the selected radio-frequency channel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radio communication apparatus that performs transmission / reception selectively using a plurality of radio frequency channels.

  When direct communication is performed between wireless communication devices, there is a possibility that communication quality may deteriorate due to interference due to the presence of various jamming waves that arrive due to the surrounding environment. As the interference source, for example, noise emission from an electronic device installed in the vicinity of the wireless communication device, interference due to an external incoming wave whose generation source cannot be specified, and the like can be considered.

  Normally, wireless communication devices have selectivity characteristics that attenuate interference waves other than the desired signal using a filter inside the radio. Therefore, if the interference signal has a frequency different from that of the desired signal, it can withstand a certain level of interference interference. Has the ability to However, if the corresponding interference wave is the same as the frequency of the desired wave, this problem can no longer be solved by the conventional radio, and the weak radio signal can be removed by removing the electronic equipment that is the noise radiation source or by using the relay amplifier. There is no choice but to communicate at a desired wave level that exceeds the interference wave level so that relay communication operation is performed by amplifying the signal.

In addition, in a multi-channel access wireless communication system, a technique for accurately detecting a received electric field strength has been disclosed in order to determine a coverage area (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-247075

  As described above, in the wireless communication apparatus, when the reception frequency of the desired wave and the reception frequency of the interference wave are the same, and it is difficult to remove the interference wave source or to make a capital investment using a relay amplifier, the communication quality is reduced, There is a possibility that the communication connection becomes unstable or the communication connection itself becomes impossible. In actual operation, it is difficult to completely grasp a complicated radio wave environment, and the communication quality may deteriorate due to the radio wave environment that changes every moment.

  The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide a wireless communication apparatus capable of performing highly reliable wireless communication while avoiding interference due to arrival of jamming waves. .

  In order to achieve the above object, the present invention is a wireless communication apparatus that is provided in each of a plurality of mobile stations and transmits / receives a radio signal to / from other mobile stations within a communication range via a plurality of radio frequency channels. A means for detecting a received electric field strength from radio signals received by each of the plurality of radio frequency channels, and a level of an interference wave based on the detected received electric field strength of each radio frequency channel. Means for determining whether or not the value exceeds a value, and when it is determined that the level of the disturbing wave exceeds a predetermined value, the received electric field strength is greater than or equal to a predetermined threshold for receiving the desired wave. And a means for setting priorities as candidates for communication channels in order from the radio frequency channel with the lowest received electric field strength, and the plurality of radios according to the set priorities Means for selecting a radio frequency channel having a higher priority from wave number channels, and means for establishing a communication path with the other mobile station using the selected radio frequency channel. And

  In the above configuration, in a wireless communication system of the multi-channel access method, the received input electric field strength is detected for each radio frequency channel, and this is used as a judgment material for estimating the superiority or inferiority of the surrounding radio wave environment. The frequency channel is automatically selected for communication. That is, by assuming that all the received inputs other than the desired wave are jamming waves, the wireless communication device detects the level of the jamming wave existing in the surrounding environment when detecting a high received electric field strength other than the desired wave. It is determined that the radio frequency channel is high, and the radio frequency channel is not selected because the communication quality is degraded or impossible. When a received electric field strength at a low level is detected, it is determined that the interference wave level existing in the surrounding environment is low, and the radio frequency channel is preferentially used.

  Therefore, according to the present invention, it is possible to provide a wireless communication apparatus that can avoid interference due to the arrival of jamming waves and perform highly reliable wireless communication.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a configuration example showing an embodiment of a wireless communication system using a wireless communication apparatus according to the present invention and interference sources existing in the vicinity.
In FIG. 1, wireless communication is performed between a wireless communication device 1-1 and a wireless communication device 1-2 via a transmission / reception wave 2. At this time, the electromagnetic noise 4 emitted from the electronic device 3 existing in the vicinity, the noise 5 coming from the outside where the source is unknown, or the electromagnetic wave 7 emitted by the wireless communication device 6 belonging to the same wireless communication system is transmitted. For the wireless communication device 1-1 and the wireless communication device 1-2, which are target systems, the interference wave causes a deterioration in communication quality. Since the wireless communication device 1-1 and the wireless communication device 1-2 have the same configuration, the wireless communication device 1-1 will be described below as an example.

  FIG. 2 is a block diagram illustrating a configuration of the wireless communication device 1-1. The wireless communication device 1-1 includes an antenna 21, a transmission / reception unit 22, a control unit 23, a storage unit 24, an interference wave determination unit 25, and a frequency selection unit 26. The transmission / reception unit 22 transmits / receives a radio signal to / from the communication partner radio communication device 1-2 by selectively using a plurality of radio frequency channels under the control of the control unit 23. The storage unit 24 stores an interference wave table 241 and a priority table 242.

  The interference wave determination unit 25 detects a received signal strength indication signal (RSSI: Received Signal Strength Indicator) representing the received electric field strength for each radio frequency channel with respect to all radio frequency channels or necessary radio frequency channels. The received electric field intensity obtained as a result of the detection is tabulated as an interference wave level and stored in the interference wave table 241. The interference wave determination unit 25 determines the superiority or inferiority of the surrounding radio wave environment based on the interference wave table 241. FIG. 3 shows an example of a correspondence relationship between the radio frequency channel and the received electric field strength represented by RSSI. The interference wave determination unit 25 assumes that all reception inputs other than the desired wave are interference waves, and thus detects the interference wave level existing in the surrounding environment when detecting a high-level received input electric field strength other than the desired wave. It is determined that the radio frequency channel is high and communication quality is deteriorated or communication is impossible. On the other hand, when the received input electric field strength at a low level is detected, it is determined that the interference wave level existing in the surrounding environment is low.

  The frequency selection unit 26 creates a priority table 242 for selecting an optimum reception frequency channel based on the created interference wave table 241. For example, in FIG. 3, when selecting a radio frequency channel, L1, L3, L2,... In the order of channels that are equal to or higher than a predetermined threshold L0 for receiving a desired wave and have a lower level of interference. Priorities are set as reception frequency channel candidates in order, and stored in the priority table 242. The frequency selection unit 26 selects a radio frequency channel having a high priority from a plurality of radio frequency channels according to the priority table 242 and uses the selected radio frequency channel to communicate with the radio communication device 1 of the communication partner. -2 is established.

Next, the operation of the wireless communication device 1-1 configured as described above will be described.
(Interference wave table update processing)
FIG. 4 is a flowchart showing the procedure and contents of the interference wave table update process.
The control unit 23 of the wireless communication apparatus 1-1 uses the interference wave determination unit 25 to determine the interference wave level for all radio frequency channels or necessary radio frequency channels. In FIG. 4, the control unit 23 detects the received electric field strength based on the RSSI (step S4a). Then, it is determined whether or not synchronization can be established according to a protocol specific to the own communication system (step S4b). In this determination, when synchronization is established, it is determined as a desired wave, and the process proceeds to the next channel (step S4c). In the above determination, if synchronization is not achieved, it is determined as an interference wave (step S4d). When it is determined as an interference wave, the value of the received electric field strength of the radio frequency channel is updated in the interference wave table 241 (step S4e).

(Frequency channel selection process)
FIG. 5 is a flowchart showing the frequency channel selection processing procedure and its contents. Here, a case where three frequency channels are used as reception frequency channel candidates is shown.
The control unit 23 uses the frequency selection unit 26 to create a priority table 242 that is a candidate for three reception frequency channels (f1 to f3) from the interference wave table 241 (step S5a). Next, the created priority order table 242 is transmitted to the wireless communication device 1-2 that is the communication partner (step S4b). The wireless communication device 1-2 that is the communication partner selects a radio frequency channel having a higher priority from a plurality of radio frequency channels as a transmission frequency channel according to the priority table 242, and transmits the transmission source of the priority table 242. A wireless signal is transmitted to the wireless communication apparatus 1-1 for a certain period of time.

  Similarly, the wireless communication device 1-1 that has transmitted the priority table 242 selects a radio frequency channel as a reception frequency channel in descending order of priority according to the priority table 242, and sequentially performs reception processing. It is determined whether or not synchronization has been achieved according to a protocol unique to the communication system (steps S5c to 5e). In the above determination, the synchronized channel is set as the reception frequency channel (steps S5f to 5i). This frequency setting is notified to the wireless communication device 1-2 that is the communication partner (step S5j), and the communication frequency is established by determining the transmission frequency channel. Thereafter, communication is performed with the wireless communication device 1-2 as the communication partner using the set frequency channel until the frequency selection process is performed again (step S5k).

  At this time, the same processing as described above is performed for the wireless communication device 1-2 that is the communication partner, so that both wireless communication devices 1-1 and 1-2 can adaptively establish a communication path with higher quality. It becomes possible to select.

  As described above, in the above-described embodiment, the control unit 23 of the wireless communication device 1-1 detects the received electric field strength from the radio signals received by each of the plurality of radio frequency channels by the interference wave determination unit 25, respectively. The detected reception field strength of each radio frequency channel is stored in the interference wave table 241 as the interference wave level. The control unit 23 uses the frequency selection unit 26 as communication channel candidates in order from a radio frequency channel whose reception field strength is equal to or higher than a predetermined threshold for receiving a desired wave and whose reception field strength is low. Priorities are set and a priority table 242 is created. The control unit 23 selects a radio frequency channel having a higher priority from a plurality of radio frequency channels according to the priority table 242 and uses the selected radio frequency channel to communicate with the partner radio communication apparatus. Establish a communication path.

  That is, assuming that all the received inputs other than the desired wave are interference waves, the wireless communication device 1-1 can detect the interference existing in the surrounding environment when detecting a high-level received electric field strength other than the desired wave. It is determined that the wave level is high, and the radio frequency channel is not selected because the communication quality is degraded or impossible. On the other hand, when a low received electric field strength is detected, it is determined that the interference wave level present in the surrounding environment is low, and the radio frequency channel is preferentially used.

  In this way, since the wireless communication device 1-1 continues to select a higher-quality radio frequency channel, even in a situation where it is assumed that the radio wave environment changes every time and communication quality is deteriorated, interference is also caused. Interference due to the arrival of waves can be avoided and highly reliable wireless communication can be performed.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

The figure which shows the structural example which shows one Embodiment of the radio | wireless communications system using the radio | wireless communication apparatus which concerns on this invention, and the interference source which exists around. 1 is a block diagram illustrating a configuration of a wireless communication device. The figure which shows an example of the correspondence of a radio frequency channel and an interference wave level. The flowchart which shows the procedure of the update process of an interference wave table, and its content. The flowchart which shows the procedure of the selection process of a frequency channel, and its content.

Explanation of symbols

  1-1, 1-2 ... wireless communication device, 2 ... wireless communication, 3 ... electronic device, 4 ... interference wave emitted from electronic device, 5 ... foreign incoming interference wave, 6 ... other wireless communication device, 7 ... other Radio wave transmitted from the wireless communication device, 21 ... antenna, 22 ... transmission / reception unit, 23 ... control unit, 24 ... storage unit, 241 ... interference wave table, 242 ... priority table, 25 ... interference wave determination unit, 26 ... Frequency selector.

Claims (1)

A wireless communication device that is provided in each of a plurality of mobile stations and transmits / receives a radio signal to / from other mobile stations within a communication range via a plurality of radio frequency channels,
Means for detecting received field strength from radio signals received by each of the plurality of radio frequency channels;
Means for determining whether the level of the jamming wave exceeds a predetermined value based on the detected received field strength of each radio frequency channel;
A radio frequency channel in which the received electric field strength is equal to or higher than a predetermined threshold for receiving a desired wave and the received electric field strength is low when it is determined that the level of the disturbing wave exceeds a predetermined value Means for setting priorities as communication channel candidates in order,
Means for selecting a radio frequency channel having a higher priority from the plurality of radio frequency channels according to the set priority;
Means for establishing a communication path with the other mobile station using the selected radio frequency channel.

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