JPH0336456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to countermeasures against radio interference for a control wireless channel in a wireless communication system. In particular, the present invention relates to countermeasures against radio interference suitable for a mobile radio communication system in which the communication zone is divided into small zones, a small number of radio channels are commonly used by a large number of mobile stations, and automatic call responses are performed. [Prior Art] If interference radio waves occur in a control wireless channel, communication control becomes impossible. The cause of this interference radio wave is, for example, when a mobile device malfunctions and continues to transmit radio waves to the control channel, or when illegal radio waves are transmitted. Although the output of such jamming radio waves is small and the range of influence thereof is local, in a wireless communication system composed of small zones, communication control in that zone becomes impossible. As a countermeasure for this, when interference waves occur on the control wireless channel, a method is used to remove the effect of the interference waves by temporarily changing the frequency to a frequency that is not assigned to the control wireless channel. . [Problem to be Solved by the Invention] According to this method, the frequency to be used when interference waves are generated must be prepared in advance, so the frequency is not used effectively. The present invention solves the above-mentioned drawbacks, and satisfies the required same-channel interference protection ratio for control radio channels, and also establishes control radio channels between radio zones within a service area so as to eliminate the influence of jamming radio waves. To provide a jamming wave countermeasure method capable of effectively utilizing frequencies by performing frequency rearrangement by exchanging the frequencies of jamming waves, so that the influence of jamming waves can be removed without specifying a frequency to be used when generating jamming waves. With the goal. [Means for Solving the Problems] The present invention provides a system in which a plurality of adjacent zones are set,
A radio base station is located in each of the zones, each radio base station is coupled to one central control station by a communication line, and the radio stations within each zone communicate with the radio base station in that zone on a control channel frequency. The radio base station is controlled to start communication and set the communication channel frequency, and the control channel is assigned different frequencies to adjacent zones, and each radio base station changes its control channel frequency under control from the central control station. The radio stations in each zone are provided with means for changing the control channel frequency under control from the radio base station in that zone, and each radio base station is provided with means for changing the control channel frequency used by that radio base station. comprising means for detecting interference, and means for transmitting interference information to the central control station when the means detects interference of a predetermined level or higher, the central control station comprising:
Upon receiving the interference information from one radio base station, means for changing and resetting the control channel frequency allocation of the radio base station, and means for transmitting the changed and reset control channel frequency to each radio base station. In a wireless communication system in which each radio base station and each radio station within a zone are controlled to communicate using a control channel frequency transmitted from the central control station as a new control channel frequency, the central control station The means for changing and reconfiguring the control channel frequency allocation of the wireless base station of the station is configured to control at least the wireless base station that transmitted the interference information and the wireless base station in the zone adjacent to the zone of the wireless base station where the interference occurred. The present invention is characterized in that it includes means for changing and resetting the control channel frequency so that the channel frequency is not allocated. [Embodiments] The present invention will be explained with reference to block diagrams of embodiments in the accompanying drawings. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. Radio base stations 1 to N are each coupled to a central control station 100 via a communication network. Each of the radio base stations 1 to N has an antenna input terminal connected to a control channel receiver 25, and its output is connected to a reception control unit 2.
2 and the interference wave detection section 23. The outputs of the reception control section 22 and the jamming wave detection section 23 are input to the radio base station control section 20. The radio base station control section 20 is coupled to the central control station 100, and one output thereof is input to the control channel transmitter 24 via the transmission control section 21. Other outputs of the radio base station control section 20 are input to both the control channel transmitter and receiver. Each of the radio base stations 1 to N exchanges transmission data, reception data, etc. with the central control station 100 through a data line. The radio base stations 1 to N are controlled by a control section 20, and transmission data is transmitted from a transmitter 24 under the control of a transmission control section 21. The received data is demodulated by the receiver 25 and received by the reception control section 22. The interference radio wave detection unit 23 receives the squelch signal and demodulated reception data from the receiver 25, and determines that interference radio waves have been detected if the reception data continues to be not detected even though radio waves are being received. Then, the wireless base station controller 20 notifies the central control station 100 of this fact. Here, the feature of the present invention is that when the central control station 100 receives a notification of the detection of jamming waves, the central control station 100 detects that interference has occurred in the radio base station where the jamming radio waves were detected and the radio base stations in the zone adjacent to the radio base station where the jamming radio waves were detected. The control channel frequency is used to satisfy a required interference protection ratio by rearranging frequencies so as not to allocate the same frequency. This frequency relocation method will be explained. The service area of a mobile communication system with a small zone configuration is composed of a plurality of radio zones, and for effective frequency use, the same frequency is repeatedly used in a plurality of radio zones separated by a distance that satisfies a required value of so-called interference protection ratio. As an example, when using 12 frequencies repeatedly, as shown in Figure 2, frequencies 1, 2, ...12 are assigned as one group to 12 wireless zones, and for example, the arrows in Figure 2 are used.
The wireless zone pattern configured in a spiral in the direction of Ar is repeated to cover the entire service area. For example, if the service area is made up of 36 wireless zones, the entire service area can be covered with 12 frequencies by repeating the pattern shown in Figure 2 three times as shown in Figure 3. Let us now consider a case where the control channel of the shaded radio zone 11 (frequency number 11) receives radio wave interference in the frequency arrangement shown in FIG. At this time, frequency number 11 corresponds to the jamming wave generation zone and its six adjacent wireless zones 7 , 8 , 5 , 10 ,
Frequency number 1 may be assigned to this jamming wave generation zone so that it is not placed in areas 3 and 12 , and frequencies may be assigned to other radio zones by repeating the pattern shown in FIG. By rearranging the frequencies at least one zone apart in this manner, it is possible to eliminate the influence of the above-mentioned illegal radio waves and interference radio waves that affect about one zone due to malfunctions of mobile devices. The central control station 100 notifies all wireless base stations of the relocated frequency through the data line, and the control unit of each wireless base station receives the information and transmits the channel to the transmitter and receiver through the transmission control unit and reception control unit, respectively. Specify. At this time, channel numbers 11 and 12 with interference waves are zones far from the shaded zone, and the interference protection ratio is satisfied. In this way, all control channel transmitters and receivers are set to the rearranged frequency, and the influence of jamming waves can be removed while satisfying the required co-channel interference protection ratio, respectively. [Effects of the Invention] As explained above, the present invention, when a jamming wave is detected, satisfies the same channel interference protection ratio and eliminates the influence of the jamming wave over the entire service area. By rearranging the frequencies, it becomes unnecessary to use frequencies other than those allocated in advance, and frequencies can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a method for preventing radio interference according to an embodiment of the present invention. FIG. 2 is a wireless zone layout diagram according to an embodiment of the present invention. FIG. 3 is a wireless zone layout diagram showing sources of interference radio waves. FIG. 4 is a wireless zone layout diagram of an embodiment of the present invention configured to remove interfering radio waves. 1, 2...N... Radio base station, 20... Radio base station control unit, 21... Transmission control unit, 22... Reception control unit, 23... Jamming radio wave detection unit, 24... Control channel transmitter , 25...control channel receiver, 1-12...wireless zones in frequency number order,
Ar...Arrow indicating frequency number order, 100...Central control station.

Claims (1)

[Claims] 1. A plurality of adjacent zones are set, a wireless base station is placed in each of the zones, each wireless base station is connected to one central control station via a communication line, and wireless communication within each zone is established. The station is controlled to communicate with the radio base station in its zone using the control channel frequency, start communication, and set the communication channel frequency. The stations are provided with means for changing their control channel frequencies under control from the central control station, the radio stations in each zone are provided with means for changing their control channel frequencies under control from the radio base station of that zone, and each radio The base station includes a means for detecting interference on the control channel frequency used by the wireless base station, and when the means detects interference of a predetermined level or higher, transmits interference information to the central control station. means for changing and resetting the control channel frequency allocation of the wireless base station when the central control station receives the interference information from one wireless base station; means for transmitting the control channel frequency to each radio base station, and each radio base station and each radio station within the zone performs communication using the control channel frequency transmitted from the central control station as a new control channel frequency. In a wireless communication system controlled by 1. A control channel allocation method for a wireless communication system, comprising means for changing and resetting a control channel frequency so that a control channel frequency where interference occurs is not allocated to a wireless base station in a zone.