Radio relay system

Abstract

To solve the problem that it becomes a communication failure when there is a disturbing radio wave in a relay device or a communication terminal, in a radio relay system that performs a half complex communication system group communication using an objective wave.SOLUTION: Each of a relay device 50 and each communication terminal 60 comprises reception demodulation parts RX02 and RXn2 that search a blank objective wave by performing a patrol scanning of an available channel group with modulation transmission parts TX01 and TXn1 (n=1, 2, and 3) for a transmission and a reception and reception demodulation parts RX01 and RXn1. When there is a disturbing radio wave in the RX01 of the relay device 50, a separation level from a non-blank objective wave in the blank objective wave searched by the RX02 is changed and set to the maximum objective wave, and transmits a channel change request (CCR) from the TX01. A CCR is received by the patrol scanning of the RXn2 in each communication terminal 60, and the objective wave for the transmission and the reception of an own device is changed and set to one corresponded to a reception channel of the CCR. When there is the disturbing radio wave in a communication terminal 60a, the CCR is transmitted to the same terminal 60a → the relay device 50 → the other terminals 60b and 60c sequentially.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a wireless relay system comprising a wireless repeater and a plurality of wireless communication terminals that communicate with each other in a half-duplex manner through the wireless repeater, and automatically changes the currently used pair channel to an available pair channel when there is interfering radio wave to the wireless repeater or the wireless communication terminal.

Background Art

[0002] Conventionally, in group communication using a business wireless communication device which is a specific low-power radio station, a wireless repeater (master station) is often provided for the purpose of expanding the communication area, communicating with multi-story buildings or separate buildings, ensuring calls in areas where radio waves are difficult to reach due to obstacles, etc., and improving the call quality, and a group communication network is configured by wireless communication terminals via the wireless repeater. In addition, in a business wireless communication device which is a radio station (for work communication) of a land mobile service with an antenna power of 1 mW or less, calls between slave stations via a master station are basically used, and the same group communication network as described above is formed.

[0003] In those networks, communication between each wireless communication terminal via a wireless repeater is in a half-duplex manner, and a pair channel (opposite wave) is used for the uplink and downlink waves related to the communication. The available pair channels are determined according to the radio wave type and communication method based on the standards established in the Radio Law Enforcement Regulations and the Radio Equipment Regulations (see Non-Patent Documents 1 and 2 below). When the wireless repeater and each wireless communication terminal correspond to specific low-power radio stations, 27 sets of pair channels in FIG. 3A can be used.

[0004] Here, it is assumed that the group communication network has a schematic configuration consisting of a wireless repeater 100 and two wireless communication terminals 201 and 202 as shown in FIG. 22. The wireless repeater 100 and each wireless communication terminal 201, 202 are in a state of using the paired channel of channel number CH1, and the channels on the L-band side and H-band side of the same paired channel are set for the wireless repeater 100 and each wireless communication terminal 201, 202 in an inverse relationship with respect to transmission and reception. Specifically, the reception demodulation unit RX01 of the wireless repeater 100 is set to the channel on the L-band side of channel number CH1, and the modulation transmission unit TX01 is set to the channel on the H-band side of the same channel number. The reception demodulation units RX11, RX21 of each wireless communication terminal 201, 202 are set to the channel on the H-band side of channel number CH1, and the modulation transmission units TX11, TX21 are set to the channel on the L-band side of the same channel number. Also, the group identification information of this group communication network is set to the code "01", and this code is always included in the signal for transmission during communication, and the detection and confirmation of the same code are performed during reception.

[0005] Therefore, when the wireless communication terminal 201 makes a call to the wireless communication terminal 202 from the standby state shown in FIG. 22 to perform communication, as shown in FIG. 23, the upstream wave from the wireless communication terminal 201 to the wireless repeater 100 becomes the channel on the L-band side of channel number CH1, and the downstream wave becomes the channel on the H-band side of the same channel number. Conversely, in the case of communication where the wireless communication terminal 202 side calls the wireless communication terminal 201, the same channel usage conditions naturally apply, and each wireless communication terminal 201, 202 can intermittently perform communication in a half-duplex mode while the transmission and reception are switched.

[0006] By the way, when the operation of another communication network is started in a location close to the operation area of the group communication network, as shown in FIG. 24, if a wireless communication terminal 301 outside the group (group identification information is the code "02") uses the channel of channel number CH1 for communication during the standby state that is the interval between the above-mentioned communications, the wireless repeater 100 will be occupied, and each wireless communication terminal 201, 202 will be in a busy state as a result of carrier sense because they are specific low-power radio stations. In any case, the communication between each wireless communication terminal 201, 202 will be in an unavailable state. The cause of this communication failure state is not limited to the radio waves of the wireless communication terminal 301 outside the group as described above, but a communication failure state also occurs when there is a strong noise source in the vicinity.

[0007] In that case, group communication can be resumed by waiting until the interfering radio waves on the channel with channel number CH1 end. However, it is also unknown at what timing the interfering radio waves will occur again, and stable communication cannot be expected as long as the paired channel with channel number CH1 is used. Therefore, the optimal countermeasure is to change the current paired channels used in the group communication network to other available paired channels.

[0008] Regarding this problem, Patent Document 1 below proposes a repeater device and a communication terminal that maintain the wireless relay function even when communication becomes impossible due to interfering radio waves, fading, etc. This repeater device includes a control channel repeater and a plurality of communication channel repeaters, which are units that function as repeaters at the transmission and reception frequencies set for each of them. However, here, the so-called control channel is assumed to correspond to the frequency control channel specially provided as channel number 19 in addition to the 27 sets of paired channels in FIG. 3A for the specific low-power radio station. On the other hand, each communication terminal that communicates via the repeater device records transmission failure information indicating that the repeater device did not respond or / and transmission retransmission count information (hereinafter referred to as "transmission failure information") when making a call to the repeater device via the control channel, and adds the transmission failure information to the signal transmitted to the repeater device via the control channel and then transmits it.

[0009] The repeater device, as functional means, includes a control channel state detection means for recording transmission failure information received from the communication terminal side via a control channel, a means for comparing the transmission failure information with preset threshold information, a communication channel idle detection means for detecting whether the communication channel repeater is in an idle state, a control channel switching information generation means for generating information to switch the communication channel repeater in the idle state to the control channel repeater when the transmission failure information exceeds the threshold, and a repeater switching means for transmitting the generated control channel switching information to the communication terminal and switching the corresponding communication channel repeater to the control channel repeater based on the control channel switching information. Thereby, when the communication state of the control channel repeater deteriorates, the function is delegated to a communication channel repeater with a good communication state.

[0010] Therefore, the proposal in Patent Document 1 below is to delegate the function of the control channel repeater to a communication channel repeater in an idle state when interference waves or the like occur in the control channel and the control channel repeater stops functioning. However, in paragraph

[0007] , it is described that "Regarding the communication channel repeater as well, when its communication quality deteriorates, it is possible to maintain a normal relay function by using a normal control channel repeater or a control channel as a communication channel." It is suggested that even when interference waves or the like occur in the communication channel, switching from the communication channel repeater to another communication channel repeater is possible.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Non-Patent Documents

[0012]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0013] As described above, in the proposal of Patent Document 1, in the repeater device, when interference waves or the like occur in the control channel, the function of the control channel repeater is borne by the communication channel repeater. Also, although not specifically disclosed, when interference waves or the like occur in the communication channel, the function is also shifted from the communication channel repeater to other communication channel repeaters or the control channel repeater.

[0014] However, the repeater device is equipped with channel repeaters (a control channel repeater and a plurality of communication channel repeaters) as units for each channel, and each channel repeater is equipped with a reception demodulation unit and a modulation transmission unit with set transmission and reception frequencies (pair channels in the case of a specific low-power radio station). Therefore, if it is a repeater device that can support 27 pairs of channels, the reception demodulation units and modulation transmission units will naturally be incorporated in 28 units each, including the control channel, resulting in an expensive device. In the case of a wireless relay system using the semi-duplex method, a large number of communication channel repeaters in a non-use state will occur, leading to extremely poor utilization efficiency.

[0015] Also, in the repeater device, when interference waves or the like occur in the communication channel during the relay operation, it is acceptable to shift from the communication channel repeater to other communication channel repeaters. However, when notifying the communication terminal side of information related to the change of the communication channel, the control channel repeater will be used. In that case, since the control channel is a channel for transmitting and receiving information for the purpose of frequency control, it tends to be used frequently compared to other communication channels. Therefore, when a similar communication network is operating in the vicinity, the likelihood of the busy state being continuously unavailable increases.

[0016] Also, when interference waves or the like occur in one communication channel repeater and the relay operation is shifted to a communication channel repeater in the idle state, if there are a large number of communication channel repeaters, a large number of communication channel repeaters in the idle state may be detected by the communication channel idle detection means. However, even for a communication channel in the idle state, there may be radio wave interference if a communication channel of an adjacent frequency is being used.

[0017] The present invention was created in consideration of the above problems. In a wireless communication system comprising a wireless repeater and a plurality of wireless communication terminals, in which each wireless communication terminal performs group communication via the wireless repeater using paired channels for the uplink and downlink, when a wireless repeater or a wireless communication terminal detects and confirms that there is interference radio wave with respect to the currently used paired channel, the function of automatically changing the paired channel to another available paired channel is reasonably realized with a relatively simple configuration and without using the control channel.

Means for Solving the Problems

[0018] The first invention comprises a wireless repeater and a plurality of wireless communication terminals forming a group, and selects one pair of channels (hereinafter referred to as "paired channels"), which can be used for the upstream and downstream waves related to the communication between the wireless repeater and each wireless communication terminal in the standard specifications formulated based on the Radio Law Enforcement Regulations and the Radio Equipment Regulations, to perform group communication between the wireless communication terminals by means of a half-duplex system. The wireless repeater includes a reception demodulation unit A, a reception demodulation unit B, a modulation transmission unit C, and a control unit for controlling them. The one paired channel is set for the reception demodulation unit A and the modulation transmission unit C, while the reception demodulation unit B scans the group of channels that can be used as the reception channel of the reception demodulation unit A to search for an available channel. In the standby / reception mode, the reception demodulation unit A and the reception demodulation unit B are in the ON state, and the modulation transmission unit C is in the OFF state. When the group identification information related to the group is detected and confirmed from the demodulation signal of the reception demodulation unit A, it switches to the relay mode. In the relay mode, the modulation transmission unit C is in the ON state, and the carrier wave of the transmission channel is modulated and transmitted with the demodulation signal output by the reception demodulation unit A. In addition, in the standby / reception mode, when the reception demodulation unit A receives radio waves with a certain electric field strength or more for a predetermined time or more and cannot detect and confirm the group identification information from its demodulation signal, the set paired channel of the reception demodulation unit A and the modulation transmission unit C is changed to the paired channel related to the available channel searched by the reception demodulation unit B, and the modulation transmission unit C is set to the ON state to transmit the group identification information and the channel change request information. Each wireless communication terminal includes a reception demodulation unit D, a reception demodulation unit E, a modulation transmission unit F, and a control unit for controlling them. The paired channels set for the reception demodulation unit D and the modulation transmission unit F on the wireless repeater side are set in an inverse relationship for transmission and reception, while the reception demodulation unit E scans the group of channels that can be used as the reception channel of the reception demodulation unit D to search for an available channel. In the standby / reception mode, the reception demodulation unit D and the reception demodulation unit E are in the ON state, and the modulation transmission unit F is in the OFF state, and the demodulation signal output by the reception demodulation unit D is used for voice playback. In the transmission mode, the reception demodulation unit D and the reception demodulation unit E are in the OFF state, and the modulation transmission unit F is in the ON state,The input voice signal modulates and transmits the carrier wave of the transmission channel of the modulation transmission unit F. In addition, in the standby / reception mode, when the reception demodulation unit E receives the group identification information and the channel change request information transmitted by the wireless repeater side during its scanning process, the reception channel and the channel in a paired channel relationship with it are respectively set in the reception demodulation unit D and the modulation transmission unit F. It relates to a wireless relay system characterized by this.

[0019] This first invention relates to a wireless relay system for automatically changing the currently used channel of a group communication network when a wireless repeater receives interfering radio waves. Regarding the determination of interfering radio waves, it is assumed that group identification information cannot be detected and confirmed from the demodulated signal of the reception demodulation unit A, that the radio wave has a certain field strength or more, and that the reception continues for a predetermined time or more. When the radio waves of wireless communication terminals not belonging to the group or other noise sources harm the voice call of the group communication and continue for a certain time, it is determined that there are interfering radio waves. In this invention, the wireless repeater and each wireless communication terminal are each provided with a reception demodulation unit B and a reception demodulation unit E for channel scanning in addition to the reception demodulation unit A and the reception demodulation unit D for original signal reception. In the wireless repeater, by the scanning operation of the reception demodulation unit B in the standby / reception mode, an empty paired channel is searched from the group of channels that can be used as the reception channel of the reception demodulation unit A. In each wireless communication terminal, by the scanning operation of the reception demodulation unit E in the standby / reception mode, the information transmission radio waves from the wireless repeater that cannot be received on the currently set channel of the reception demodulation unit D are received. Then, in the wireless repeater, when there is the interfering radio wave with respect to the reception demodulation unit A, the empty paired channel previously searched by the reception demodulation unit B is changed and set in the reception demodulation unit A and the modulation transmission unit C, and the group identification information and the channel change request information are transmitted from the modulation transmission unit C through the empty channel. On the other hand, on each wireless communication terminal side, when the group identification information and the channel change request information transmitted from the wireless repeater are received during the scanning process of the reception demodulation unit E, the paired channel related to the reception channel is changed and set for the reception demodulation unit D and the modulation transmission unit F. In that case, although the channels reconfigured for the reception demodulation unit A and the modulation transmission unit C on the wireless repeater side and the channels reconfigured for the reception demodulation unit D and the modulation transmission unit F on each wireless communication terminal side are naturally the same available paired channels, the relationship between transmission and reception of the channels is reversed between the wireless repeater side and each wireless communication terminal side. As a result, according to the wireless relay system according to the first invention, when the wireless repeater receives interfering radio waves, it can automatically change the paired channels used for group communication to other available paired channels, enabling half-duplex wireless communication in a good state with a high signal-to-noise ratio free from the influence of interfering radio waves.

[0020] In the wireless repeater of the wireless communication system according to the first invention, when the reception demodulation unit A receives radio waves with a certain field strength or more from which the group identification information cannot be confirmed from its demodulated signal for a predetermined time or more, and a plurality of available paired channels are detected in the one-round scanning process by the reception demodulation unit B immediately before the reception for the predetermined time or more is detected, it is desirable that the available paired channel with the largest frequency separation from the non-available paired channel be reconfigured for the reception demodulation unit A and the modulation transmission unit C, and the modulation transmission unit C be controlled to transmit the group identification information and the channel change request information.

[0021] The paired channels are defined by the standard specifications of the wireless facilities of various wireless stations, and in each standard specification, a number of available paired channels are prepared in ascending order at a predetermined frequency interval. Therefore, depending on conditions such as the installation location of the wireless repeater, a large number of available paired channels are often detected in the one-round scanning process in the reception demodulation unit B. By the way, for example, the frequency interval between each pair of channels in the standard specifications in Non-Patent Document 1 above is 12.5 kHz for channel numbers 1 to 18 and 25.0 kHz for channel numbers 32 to 40 as shown in FIG. 3A. It is assumed that there is no interference between pair channels with different channel numbers. However, if another group's wireless communication system in a neighboring area is operating using channels with adjacent channel numbers, if there is a strong noise source such as a microwave oven in a neighboring restaurant, or if an illegal radio station or the like is operating at a nearby frequency or if abnormal radio wave propagation occurs, etc., even if the channel numbers are different, radio wave interference may occur and it may interfere with call communication. Therefore, in the wireless repeater according to the first invention, when the reception demodulation unit B detects a plurality of available pair channels during its one-round scanning process immediately before the reception of interfering radio waves is detected by the reception demodulation unit A, the available pair channel having the largest frequency separation from the non-available pair channels (including the currently set pair channels) is selected from among these available pair channels and is re-set for the reception demodulation unit A and the modulation transmission unit C, so that an available pair channel that is not affected by radio wave interference as much as possible is selected. Then, the wireless repeater causes the modulation transmission unit C to transmit group identification information and channel change request information through the selected available channel, and also re-sets the transmission and reception channels on each wireless communication terminal side to the available channel. Therefore, it is possible to more effectively eliminate the influence of interfering radio waves and to realize a half-duplex wireless communication with high signal-to-noise ratio without radio wave interference.

[0022] Also, when the wireless repeater of the wireless communication system according to the first invention selects an available pair channel considering the frequency separation from non-available pair channels from among the available pair channels as described above and re-sets the reception demodulation unit A and the modulation transmission unit C, and when it is necessary to perform carrier sense using the reception demodulation unit A prior to the transmission operation of the modulation transmission unit C, it is desirable to control the selection of available pair channels in descending order of the frequency separation from non-available pair channels and perform carrier sense.

[0023] In the wireless repeater, except for those with a transmission antenna power of 1 mW or less, it is necessary to perform carrier sense prior to the transmission operation. However, in order to perform carrier sense on the available paired channel detected in one cycle scan immediately before the reception demodulation unit B detects the reception of interfering radio waves, it should be in an idle state in most cases. However, in a congested network environment, even in a short period until the carrier sense is performed, the result of the carrier sense may be in a busy state for reasons such as another group starting to use the available channel that is the target of the carrier sense. Considering such circumstances, in this wireless repeater, the selection criterion for the available paired channel that is the target of the next carrier sense when the result of the carrier sense becomes unacceptable for transmission is set to be in descending order of the frequency separation degree from the current setting paired channel, so that an available paired channel that is less likely to be affected by interfering radio waves is selected as much as possible.

[0024] The second invention comprises a wireless repeater and a plurality of wireless communication terminals forming a group, and selects one pair channel from a group of two channels (hereinafter referred to as "pair channels") that can be used for the upstream and downstream waves related to the communication between the wireless repeater and each wireless communication terminal in the standard specifications formulated based on the Radio Law Enforcement Regulations and the Radio Equipment Regulations, and performs group communication between the wireless communication terminals by a half-duplex method. The wireless repeater includes a reception demodulation unit A, a reception demodulation unit B, a modulation transmission unit C, and a control unit for controlling them. The one pair channel is set for the reception demodulation unit A and the modulation transmission unit C, while the reception demodulation unit B scans a group of channels that can be used as the reception channel of the reception demodulation unit A. In the standby / reception mode, the reception demodulation unit A and the reception demodulation unit B are in the ON state, and the modulation transmission unit C is in the OFF state. When group identification information related to the group is detected and confirmed from the demodulation signal of the reception demodulation unit A, it switches to the relay mode. In the relay mode, the modulation transmission unit C is turned on, and the carrier wave of the transmission channel is modulated and transmitted with the demodulation signal output by the reception demodulation unit A. In addition, in the standby / reception mode, when the reception demodulation unit B receives the group identification information and the channel change request information transmitted by any of the wireless communication terminals during its scanning process, it sets the reception channel and the channel in a pair channel relationship with it to the reception demodulation unit A and the modulation transmission unit C respectively, and transmits the group identification information and the channel change request information from the modulation transmission unit C. Each wireless communication terminal includes a reception demodulation unit D, a reception demodulation unit E, a modulation transmission unit F, and a control unit for controlling them. The pair channel set for the reception demodulation unit A and the modulation transmission unit C on the wireless repeater side is set for the reception demodulation unit D and the modulation transmission unit F in a reverse relationship for transmission and reception, while the reception demodulation unit E scans a group of channels that can be used as the reception channel of the reception demodulation unit D and searches for an idle channel. In the standby / reception mode, the reception demodulation unit D and the reception demodulation unit E are in the ON state, and the modulation transmission unit F is in the OFF state, and the demodulation signal output by the reception demodulation unit D is used for voice playback. In the transmission mode, the reception demodulation unit D and the reception demodulation unit E are in the OFF state, and the modulation transmission unit F is in the ON state,The input voice signal modulates and transmits the carrier wave of the transmission channel of the modulation transmission unit F. In addition, in the standby / reception mode, when the reception demodulation unit D receives a radio wave with a certain field strength or higher for a predetermined time or longer and cannot detect and confirm the group identification information from its demodulated signal, the reception demodulation unit E searches for the set pair channels of the reception demodulation unit D and the modulation transmission unit F and changes them to the pair channels related to the available channels it has searched. At the same time, the modulation transmission unit F is turned on to transmit the group identification information and the channel change request information. On the other hand, when the reception demodulation unit E receives the group identification information and the channel change request information transmitted by the wireless repeater side during its scanning process, it sets the received channel and the channel in the pair channel relationship with it to the reception demodulation unit D and the modulation transmission unit F respectively. It relates to a wireless relay system characterized by this.

[0025] This second invention relates to a wireless relay system for automatically changing the used channels of a group communication network when a wireless communication terminal, rather than a wireless repeater, receives interfering radio waves. Also in this invention, similar to the first invention, the wireless repeater and each wireless communication terminal are each provided with a reception demodulation unit B and a reception demodulation unit E for channel scanning in addition to the reception demodulation unit A and the reception demodulation unit D for original signal reception. However, in the case of this second invention, the reception of interfering radio waves by the reception demodulation unit D of any one wireless communication terminal is the starting point, and the wireless communication terminal sets the available pair channels searched by the reception demodulation unit E to the reception demodulation unit D and the modulation transmission unit F and transmits the group identification information and the channel change request information. On the other hand, the wireless repeater plays the role of propagating the channel change request to wireless communication terminals other than the one wireless communication terminal. When it receives the group identification information and the channel change request information during the scanning process of the reception demodulation unit B, it changes and sets the pair channel related to the received channel to the reception demodulation unit A and the modulation transmission unit C, and transmits the group identification information and the channel change request information from the modulation transmission unit C. Thereafter, when each wireless communication terminal receives the group identification information and the channel change request information from the wireless repeater during the scanning process of its reception demodulation unit E, similar to the case of the first invention, the reception channel and the channel in a paired channel relationship with it are respectively set in the reception demodulation unit D and the modulation transmission unit F. As a result, both the wireless repeater and each wireless communication terminal can automatically change the paired channels used for group communication from the state with interfering radio waves to other available paired channels, enabling half-duplex wireless communication in a good state with a high signal-to-noise ratio. Note that the group identification information and the channel change request information from the wireless repeater are received by both the reception demodulation unit D and the reception demodulation unit E even in a wireless communication terminal in which the reception demodulation unit D and the modulation transmission unit F have already been set to available paired channels due to receiving interfering radio waves. In that case, the wireless communication terminal may also reset the available paired channels, but it can also be ignored due to the direct reception in the reception demodulation unit D.

[0026] In each wireless communication terminal of the wireless communication system according to the second invention, when the reception demodulation unit D receives radio waves with a certain electric field strength or more for a predetermined time or more and cannot confirm the group identification information from its demodulated signal, and a plurality of available paired channels are detected during one scanning process by the reception demodulation unit E immediately before the reception for the predetermined time or more is detected, it is desirable to change and set the available paired channel with the largest frequency separation from the non-available paired channel in the reception demodulation unit D and the modulation transmission unit F, and to control the modulation transmission unit F to transmit the group identification information and the channel change request information.

[0027] Also, in the wireless communication terminal of the wireless communication system according to the second invention, when performing carrier sense using the reception demodulation unit D prior to the transmission operation of the modulation transmission unit F, it is desirable to control to select available paired channels in descending order of the frequency separation from the non-available paired channel and perform carrier sense.

[0028] The selection method for these available paired channels pertains to the same control as in the case where the wireless repeater in the first invention receives interfering radio waves. It more effectively eliminates the influence of interfering radio waves and realizes wireless communication in a half-duplex mode with a high signal-to-noise ratio without radio wave interference.

Advantages of the Invention

[0029] The present invention comprises a wireless repeater and a plurality of wireless communication terminals constituting a group. In a wireless relay system that selects one paired channel from a group of paired channels that can be used for the uplink and downlink related to communication between the wireless repeater and each wireless communication terminal in a standard specification formulated based on the Radio Law Enforcement Regulations and the Radio Equipment Regulations, and performs group communication between wireless communication terminals in a half-duplex mode, when the wireless repeater or a wireless communication terminal receives interfering radio waves, from among a plurality of available paired channels that have been previously searched by means of a cyclic scan of the paired channel group, the available paired channel with the largest frequency separation from the non-available paired channels (including the currently set paired channel that has received interfering radio waves) is selected and set as a change in place of the currently set paired channel, thereby enabling the more effective elimination of the influence of interfering radio waves and realizing wireless communication in a half-duplex mode with a high signal-to-noise ratio without radio wave interference.

Brief Description of the Drawings

[0030]

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Mode for Carrying Out the Invention

[0031] Hereinafter, embodiments of the wireless relay system according to the present invention will be described in detail with reference to FIGS. 1 to 20. However, in this embodiment, it is assumed that the wireless repeater and the wireless communication terminal comply with the specific low-power wireless station / wireless equipment for wireless telephones according to the above Non-Patent Document 1.

[0032] <Configuration of Wireless Repeater> The wireless repeater 50 according to the embodiment has the configuration shown in FIG. 1. In the figure, 51 is a receiving antenna, RX01 and RX02 are receiving demodulation units, TX01 is a modulation transmission unit, 52 is a transmitting antenna, 53 is a system control unit, 54 is an operation unit, and 55 are various indicator lamps. The operation of the entire wireless repeater 50 is controlled by the system control unit 53. The receiving demodulation unit RX01 and the modulation transmission unit TX01 are respectively controlled and set for the upstream and downstream channels. The receiving demodulation unit RX01 demodulates the signal of the set channel from the received radio wave signal at the receiving antenna 51 and outputs it to the modulation transmission unit TX01. The modulation transmission unit TX01 modulates the carrier signal of the set channel with the demodulated signal input from the receiving demodulation unit RX01, then power-amplifies the modulated signal and emits radio waves from the transmitting antenna 52.

[0033] Here, each channel set in the reception demodulation unit RX01 and the modulation transmission unit TX01 has a relationship of a pair channel related to any one channel number in FIG. 3A. In each of the following embodiments, the channel on the L-band side is set in the reception demodulation unit RX01, and the channel on the H-band side is set in the modulation transmission unit TX01. Therefore, the wireless repeater 50 executes relay communication using a pair channel with the upstream wave as the channel on the L-band side and the downstream wave as the channel on the H-band side.

[0034] On the other hand, the reception demodulation unit RX02 is controlled to scan all the channels on the L-band side (the same band side as the reception demodulation unit RX01) in FIG. 3A in the standby / reception mode. The purpose of using this scanning of the reception demodulation unit RX02 is different in Embodiment 1 and Embodiment 2 below. In Embodiment 1, it is used to check for available pair channels during the scanning process of the L-band group and to update and store the information in the internal memory by the system control unit 53. In Embodiment 2 below, it is used to receive group identification information and channel change request signals transmitted on a channel different from the set channel of the reception demodulation unit RX01 from the wireless communication terminal 60 side.

[0035] Note that from the operation unit 54, operations such as turning the power on / off, selecting the group communication mode, selecting available pair channels, and other setting information can be performed using button operations. Various indicator lamps are lit / flashed / extinguished to indicate the mode setting state, the consumption state of the battery (not shown), etc., and the system control unit 53 also executes the management / control thereof.

[0036] <Configuration of Wireless Communication Terminal> The wireless communication terminal 60 according to the embodiment has the configuration shown in FIG. 2. In the figure, 61 is a transmission / reception antenna, 62 is an antenna switching unit, RXn1 and RXn2 are reception demodulation units, 63 is an amplifier, 64 is a speaker (or earphone), 65 is a microphone, 66 is an amplifier, TXn1 is a modulation transmitter, 67 is a system control unit, 68 is an operation unit, and 69 is a liquid crystal display unit. The operation of the entire wireless communication terminal 60 is controlled by the system control unit 67. Note that the "n" in the symbols of the reception demodulation units RXn1, RXn2 and the modulation transmitter TXn1 is a numerical value (n = 1, 2, 3...) for convenience in distinguishing the reception demodulation units and modulation transmitters in each terminal when performing group communication using a plurality of wireless communication terminals 60.

[0037] In the reception system of the wireless communication terminal 60, the radio wave signal received by the reception antenna 61 is input to the reception demodulation unit RXn1 through the antenna switching unit 62. The reception demodulation unit RXn1 demodulates only the signal related to the set channel, and the demodulated signal is amplified by the amplifier 63 and output as sound from the speaker 64. A pair channel is set for the reception demodulation unit RXn1 and the modulation transmission unit TXn1. Those channels have an inverse relationship with the pair channels set for the reception demodulation unit RX01 and the modulation transmission unit TX01 on the wireless repeater 50 side in terms of transmission and reception. In each of the following embodiments, a channel on the H-band side is set for the reception demodulation unit RXn1, and a channel on the L-band side is set for the modulation transmission unit TXn1.

[0038] On the other hand, the reception demodulation unit RXn2 is controlled to sequentially scan all channels on the H-band side (the same band side as the reception demodulation unit RXn1) in FIG. 3A in the standby / reception mode. The purpose of using the cyclic scanning of this reception demodulation unit RXn2 is different in Embodiment 1 and Embodiment 2 below. In Embodiment 1, it is used to receive group identification information and channel change request signals transmitted on a changed channel different from the set channel of the reception demodulation unit RXn1 from the following wireless repeater 50 side. In Embodiment 2, it is used to check for available paired channels by the cyclic scanning of the H-band group, and the system control unit 67 updates and stores the scanning information in the built-in memory. It is also used for the same purpose as in the case of Embodiment 1.

[0039] In the transmission system of the wireless communication terminal 60, the voice signal input from the microphone 65 is amplified by the amplifier 66, the modulation transmission unit TXn1 modulates the carrier signal of the set channel with the amplified voice signal, power-amplifies the modulated signal, and emits radio waves from the transmission antenna 61 through the antenna switching unit 62.

[0040] Note that it is necessary to switch the connection state of the antenna switching unit 62 between the antenna 61 and the modulation transmission unit TXn1 side or the reception demodulation units RXn1 and RXn2 side according to the change of the transmission / reception mode. Also, the power can be turned on / off, various communication modes can be selected, available paired channels can be selected, and other setting information can be performed by button operations or dial operations on the operation unit 68. The liquid crystal display unit 69 displays the mode setting state, the used channel, the consumption state of the battery (not shown), etc. The system control unit 67 also executes the management and control of these.

[0041] <Communication Frame Format> FIG. 3B is an example of a communication frame format diagram used in group communication in the following embodiment. On the transmission side, a modulated wave modulated by MSK (Minimum Shift Keying) or the like is transmitted by the baseband signal of the voice signal part incorporated in the same format. On the reception side, the received signal related to the modulated wave is demodulated to reproduce the voice signal, while each information signal of the data payload received prior to the voice signal is separated and detected to be used as data for operation control. In the data payload, own device identification information, group identification information, and transmission / reception channel information are set. When interference radio waves are detected in the wireless repeater 50 or the wireless communication terminal 60, a channel change request signal can also be set.

[0042] <Embodiment 1> This Embodiment 1 relates to the operations of each device 50, 60a, 60b, 60c and the system procedure when, in a wireless communication system that constitutes a group communication network in a half-duplex mode using the wireless repeater (hereinafter abbreviated as "repeater") 50 and three wireless communication terminals (hereinafter abbreviated as "communication terminals") 60 (60a, 60b, 60c), when the repeater 50 receives interference radio waves, the pair channel used for group communication is changed to another available pair channel.

[0043] The wireless relay network diagram of FIG. 4 shows the relay communication state via the repeater 50 when the transmission / reception channel for group communication is set to the pair channel CH1, with the communication terminal 60a on the transmission side and the communication terminals 60b, 60c on the reception side. Here, in all wireless relay network diagrams from FIG. 4 onwards (excluding FIGS. 22 to 24), RX01, RX02, and TX01 of the functional blocks included in the repeater 50 indicate the two reception demodulation units and the modulation transmission unit corresponding to those symbols in FIG. 1, and RXn1, RXn2, and TXn1 (n = 1, 2, 3) of the functional blocks included in the communication terminals 60a, 60b, 60c indicate the two reception demodulation units and the modulation transmission unit corresponding to those symbols in FIG. 2. Regarding "CHi-X" (i = 1, 2, X = L, H, SCAN) appended to each of the above symbols related to the reception demodulation unit and the modulation transmission unit via ":", "CHi" corresponds to the channel number related to the pair channel (see FIG. 3A), "L" or "H" indicates whether the channel is in the L band or the H band of the pair channels, and "SCAN" indicates that it is in a scanning state for all channels in the L band group or the H band group of FIG. 3A. In addition, in the functional blocks of the repeater 50 and the communication terminals 60a, 60b, and 60c, those without diagonal lines indicate the ON state, and those with diagonal lines indicate the OFF state.

[0044] In the relay communication state of FIG. 4, this relates to the case where the communication terminal 60a transmits a call voice signal on channel CH1-L with the reception demodulation units RX11 and RX12 in the OFF state and the modulation transmission unit TX11 in the ON state. In the repeater 50, when the radio wave is received and demodulated by the reception demodulation unit RX01, the modulation transmission unit TX01 is switched from the OFF state to the ON state, and a modulated signal obtained by modulating a carrier signal with the demodulated call voice signal is transmitted on channel CH1-H. On the other hand, the communication terminals 60b and 60c in the standby / reception state receive and demodulate the relayed radio wave by the reception demodulation units RX21 and RX31 and reproduce the voice.

[0045] FIG. 4 shows the case where the communication terminal 60a becomes the transmitting terminal. However, no matter which of the communication terminals 60a, 60b, and 60c becomes the transmitting terminal, group communication using a half-duplex system with channel CH1-L as the upstream wave and channel CH1-H as the downstream wave is similarly executed via the repeater 50. However, since it is group communication, the repeater 50 and the communication terminals 60a, 60b, and 60c always include the code "01" as group identification information (hereinafter referred to as "G-ID") in the data payload of the transmission signal and transmit it. Also, after confirming that the G-ID "01" is included in the data payload of the received and demodulated signal, the call voice signal is reproduced. In this embodiment, since it is network communication based on the specific low-power radio station / wireless equipment / standard specification of Non-Patent Document 1 above, the communication terminals 60a, 60b, and 60c and the repeater 50 perform carrier sense prior to transmission and confirm that they are not receiving radio waves with a predetermined field strength or more from other radio stations or the like before transmitting.

[0046] FIG. 5 shows the standby state in the wireless relay network. The communication terminal 60a that became the transmission terminal in FIG. 4 has turned off the modulation transmission unit TX11 and turned on the reception demodulation units RX11 and RX12, similar to the other communication terminals 60b and 60c. Also in the repeater 50, since there is no reception signal in the reception demodulation unit RX01, the modulation transmission unit TX01 has been switched to the OFF state.

[0047] By the way, the reception demodulation unit RX02 of the repeater 50 always scans all 27 channels in the L-band group of FIG. 3A in the standby / reception mode to check whether each channel is available, and the system control unit 53 stores the information for one round of scanning in the built-in memory in a ring buffer manner. Specifically, as described in the article on carrier sense on pages 1-10 of the above Non-Patent Document 1, it is determined whether the value of the received input power becomes -96 dBm or more at the power supply line input point for each channel over 200 msec, and a flag is set for the channels that meet this condition. By performing this operation for all 27 channels in the L-band group of FIG. 3A as one round of scanning, a scanning information table with the channels having the flag down being regarded as available is created and sequentially updated and stored in the built-in memory. In this embodiment, the 27 channels are the scanning targets. However, when the used pair channels in the wireless relay network are limited to those selected from among the 27 channels, naturally only those limited channels (for example, 10 channels) will be the targets of one round of scanning.

[0048] FIG. 6 shows the case where there is interference radio wave in the repeater 50 in the standby state (FIG. 5). Here, it shows the state where the repeater 50 has received the call voice signal from the communication terminal 70 belonging to another group (G-ID "02") by the radio wave of channel CH1-L. In that state, naturally, the signal of the interference radio wave is received and demodulated by the reception demodulation unit RX01 of the repeater 50. However, the system control unit 53 of the repeater 50 executes the procedure shown in the flowchart of FIG. 7 to change the used channel of the wireless relay network.

[0049] First, when the reception demodulation unit RX01 of the repeater 50 receives a radio wave with a predetermined electric field strength or higher in the standby state, the system control unit 53 checks the data payload of the reception demodulation signal obtained from the reception demodulation unit RX01, and determines whether the group code "01" as the G-ID can be detected (S1 to S4). Regarding the electric field strength related to the radio wave reception by the reception demodulation unit RX01 in that case, the level may be determined in consideration of whether it will interfere with voice communication. However, similar to the case of searching for an empty channel by the cyclic scanning in the reception demodulation unit RX02, it may also be based on whether the value of the received input power becomes -96 dBm or higher at the power supply line input point.

[0050] In the steps S1 to S4, when the electric field strength related to the radio wave reception by the reception demodulation unit RX01 is smaller than the reference, it is regarded as not being an interfering radio wave and remains in the standby state (S1, S2: N → S1). Also, when the GID: "01" is detected, since it corresponds to the reception of the transmission radio waves from the communication terminals 60a, 60b, and 60c within the group, the normal relay operation will be executed during the radio wave reception as shown in FIG. 4 (S4: Y → S5 → S1).

[0051] On the other hand, when the GID: "01" is not detected, the built-in interval timer starts timing (S4: N → S6), and it is confirmed whether the reception of the radio wave continues while maintaining the electric field strength (S6, S7). If the reception of the radio wave stops before the preset time set in the interval timer, the timer is reset and returns to the standby state (S7 → S8 → S1). When the timeout occurs, after resetting the timer, it proceeds to the procedure for changing the used channel of the subsequent wireless relay network (S9: Y → S10 to S15).

[0052] Here, the interfering radio wave is regarded as the communication terminal 70 of another group as shown in FIG. 6. However, it does not exclude the interfering radio wave from other radio wave sources. For the purpose of targeting radio wave reception from outside the communication terminals 60a, 60b, and 60c belonging to the group, the determination of the interfering radio wave is only conditional on the fact that "01" is not detected as the G-ID (S4). Also, if the interfering radio wave does not continue for a predetermined time (e.g., 1 sec) or more, the use channel of the wireless relay network is maintained (S9 → S7 → S8 → S1), avoiding frequent repetition of the use channel change operation due to sudden interfering radio waves that do not affect the call much.

[0053] The change of the use channel of the wireless relay network is to change and set the current setting pair channels (CH1-L and CH1-H) of the reception demodulation unit RX01 and the modulation transmission unit TX01 to the available pair channel selected based on the state information of each pair channel obtained by the previous round-robin scan by the reception demodulation unit RX02. That is, among the available pair channels detected by the reception demodulation unit RX02 through one round-robin scan of the L-band group in FIG. 3A immediately before the timeout, the available pair channel with the largest frequency separation from the non-available pair channel (here, the channel number: CH2) is selected, and the current setting pair channels (CH1-L and CH1-H) of the reception demodulation unit RX01 and the modulation transmission unit TX01 are changed and set to the selected pair channel (CH2-L and CH2-H) (S10, S11).

[0054] Specifically, in the last round of scanning just before the timeout, when a scanning information table is created in which OFF empty paired channels and ON non-empty paired channels are detected, such as the interference wave flags in the right column of FIG. 3A, and assuming that the channel number (CH1) of the current setting paired channel of the reception demodulation unit RX01 and the modulation transmission unit TX01 is 6, if there is interference wave in that paired channel, since the empty paired channel with the largest frequency separation from the non-empty paired channel in the scanning information table corresponds to channel number 32 (CH2), the empty paired channel (CH2-L and CH2-H) will be reconfigured for the reception demodulation unit RX01 and the modulation transmission unit TX01.

[0055] The method for obtaining the "empty paired channel with the largest frequency separation from the non-empty paired channel" is as follows. (1) In the column of interference flags, if there are ONs on both sides of OFF or at both ends of a continuous part of OFF, the interval between the channel frequencies related to the ONs on both sides or both ends is obtained. (2) In the column of interference flags, when the flag of channel number 1 is OFF, the interval between the channel frequency of the smallest channel number with the flag ON and the channel frequency of channel number 1 is obtained. (3) In the column of interference flags, when the flag of channel number 40 is OFF, the interval between the channel frequency of channel number 40 and the channel frequency of the largest channel number with the flag ON is obtained. (4) Compare half of the interval obtained in (1), the interval obtained in (2), and the interval obtained in (3). If the value in (1) is the largest, select the paired channel related to the channel with the frequency closest to the arithmetic mean of the paired channels related to the OFF channels sandwiched by ONs or the channel frequencies of the ONs at both ends. If the value in (2) is the largest, select the paired channel of channel number 1. If the value in (3) is the largest, select the paired channel of channel number 40 as the corresponding paired channel. Based on the interference radio wave flag in the right column of FIG. 3A, the corresponding pair channel obtained by the algorithm in (4) becomes channel number 32 (CH2) as described above.

[0056] FIG. 8 shows a state where the reception demodulation unit RX01 and the modulation transmission unit TX01 of the repeater 50 are reconfigured to the available pair channels (CH2-L and CH2-H). The repeater 50 has moved to the pair channel of channel number CH2 and is no longer affected by the interference radio waves from the communication terminal 70. However, on the side of the communication terminals 60a, 60b, and 60c, the channels used in the previous wireless relay network are still set. The repeater 50 needs to send a GID: "01" and a channel change request signal (hereinafter referred to as "CCR") to the communication terminals 60a, 60b, and 60c to set the pair channel of channel number CH2.

[0057] Therefore, the repeater 50 will turn on the modulation transmission unit TX01 reconfigured to CH2-H and send the CCR. However, prior to transmission, it is necessary to perform carrier sense for the pair channel (CH2-L or CH2-H) using the reception demodulation unit RX01 (S12). In that case, since it has been confirmed in the previous round of scanning that the pair channel of channel number CH2 is available, the result of the carrier sense should be almost idle and transmission should be possible. However, if by chance interference radio waves related to the pair channel of channel number CH2 have occurred after the previous round of scanning, the result will be busy and transmission will be impossible.

[0058] Therefore, when the result of the carrier sense becomes busy, the available pair channel with the second largest frequency separation from the non-available pair channel in the scanning information table (channel number 9 in the scanning information table) is selected and the carrier sense is re-executed (S11, S12, S13 → S14 → S12). Note that for the paired channel of the channel number that has become busy, the isolation is compared and determined with the interference wave flag set retroactively, and thereafter, the free paired channel with the m-th largest isolation is selected in the same manner. Generally, it is extremely rare to select from the third or later.

[0059] When the result of the carrier sense of the repeater 50 is in the idle state, the modulation transmission unit TX01 is turned on, and GID: "01" and CCR are transmitted on the channel on the H band side of the changed paired channel (S13 → S15). FIG. 9 shows a state in which the first carrier sense becomes idle at the paired channel (CH2-L or CH2-H) with the largest frequency isolation for the non-free paired channel, and GID: "01" and CCR are transmitted on the channel CH2-H.

[0060] At this stage, the reception demodulation unit RXn1 and the modulation transmission unit TXn1 of each communication terminal 60a, 60b, 60c remain on the previous paired channels (CH1-H and CH1-L), and GID: "01" and CCR transmitted from the repeater 50 are detected during the scanning process of the channel CH2-H in the cyclic scanning of the reception demodulation unit RXn2.

[0061] FIG. 10 shows the procedure for changing the transmission / reception setting channels on the side of each communication terminal 60a, 60b, 60c. First, each of the communication terminals 60a, 60b, 60c cyclically scans the 27 channels in the H band group of FIG. 3A with its respective reception demodulation unit RXn2 in the standby state, and once the scanning is stopped on the received channel when a radio wave with a predetermined field strength or more is received (S21 to S23). Then, the system control unit 53 checks the data payload of the reception demodulation signal obtained from the reception demodulation unit RXn2 and determines whether GID: "01" can be detected (S24, S25).

[0062] Here, when GID: "01" is not detected, the scanning of the reception demodulation unit RXn2 is restarted to return to the standby state (S25 → S26 → S21). However, when GID: "01" is detected, it is further confirmed whether the CCR is detected (S25 → S27). When the CCR is not detected, since GID: "01" is detected, it is reception related to group communication relayed by the repeater 50. The scanning of the reception demodulation unit RXn2 is restarted, and while maintaining the current channels (CH1-H, CH1-L), the reception demodulation unit RXn1 receives and reproduces the call signal, and returns to the standby state when the reception ends (S27 → S28~S30 → S21).

[0063] On the other hand, when the CCR is detected, the amplifier 64 is set to mute, and the channels of the reception demodulation unit RXn1 and the modulation transmission unit TXn1 are changed to the pair channels (CH2-L and CH2-H) related to the scan stop channel of the reception demodulation unit RXn2, and then the mute setting of the amplifier 64 is released to return to the standby state (S27 → S31~S33 → S21). In this standby state, as shown in FIG. 11, for the repeater 50 and each communication terminal 60a, 60b, 60c, the L-band and H-band channels of CH2, which are free pair channels, are set in an inverse relationship for transmission and reception.

[0064] Therefore, as shown in FIG. 12, when any one of the communication terminals 60a, 60b, 60c (communication terminal 60a in FIG. 12) transmits a call voice signal including GID: "01" in the data payload on the upstream channel CH2-L from its modulation transmission unit TXn1, the repeater 50 receives and relays it and transmits it on the downstream channel CH2-H, and each communication terminal 60a, 60b, 60c other than the transmitting terminal (communication terminals 60b, 60c in FIG. 12) receives and demodulates the relayed transmitted radio wave by the reception demodulation unit RXn1 and reproduces the voice.

[0065] As described above, in the standby state of FIG. 5 where the network channel for group communication by the half-duplex system among the communication terminals 60a, 60b, and 60c via the repeater 50 is the pair channel CH1, if there is interfering radio wave to the repeater 50, the network channel is automatically changed to the pair channel CH2 as shown in FIG. 11, enabling group communication not affected by the interfering radio wave.

[0066] <Embodiment 2> This Embodiment 2 relates to a wireless communication system that constitutes a group communication network by the half-duplex system with the repeater 50 and three communication terminals 60 (60a, 60b, 60c) in the same manner as in Embodiment 1. However, when any of the communication terminals 60 receives an interfering radio wave, it relates to the operations of each device 50, 60 and the procedure as a system when changing the pair channel used for group communication to another available pair channel.

[0067] FIG. 13 shows the case where there is an interfering radio wave to the communication terminal 60a in the standby state of FIG. 5, which corresponds to FIG. 6 in Embodiment 1, and shows the state where the communication terminal 60a receives a call voice signal from the communication terminal 70 belonging to another group (G-ID "02") by the radio wave of channel CH1-H. In that state, of course, the signal of the interfering radio wave is received and demodulated by the reception demodulation unit RX11 of the communication terminal 60a, but the system control unit 67 of the communication terminal 60a executes the procedure shown in the flowchart of FIG. 14.

[0068] That procedure is similar to the procedure in the repeater 50 in Embodiment 1 (FIG. 7), except for the part due to the difference between the communication terminal 60 and the repeater 50. First, when the reception demodulation unit RX11 of the communication terminal 60a receives a radio wave with a predetermined field strength or more in the standby state, the system control unit 67 checks the data payload of the reception demodulation signal obtained from the reception demodulation unit RX11 and determines whether GID: "01" can be detected (S41 to S44). Regarding the field strength related to radio wave reception in the reception demodulation unit RX11 in that case, similar to the case of the repeater 50 in Embodiment 1, the level may be determined in consideration of whether it causes interference to voice communication, and it may be based on whether the value of the received input power is -96 dBm or more at the power supply line input point.

[0069] In the steps S41 to S44, when the field strength related to radio wave reception in the reception demodulation unit RX11 is smaller than the reference, it is regarded as not an interfering radio wave and remains in the standby state (S41, S42: N → S42a: in FIG. 20, S81 → S41). Also, when GID: "01" is detected, since it corresponds to the reception of the transmitted radio wave sent from the communication terminals 60a, 60b, 60c in the group via the repeater 50, a call signal is received on the current channel and voice reproduction is executed, and when the reception of the call signal ends, it returns to the standby state (S44: Y → S45, S46 → S41).

[0070] On the other hand, when GID: "01" is not detected, the built-in interval timer starts timing (S44: N → S47), and it is confirmed whether the reception of the radio wave continues while maintaining the field strength (S47, S48). If the reception of the radio wave stops before the predetermined time set in the interval timer is counted, the timer is reset and it returns to the standby state (S48 → S49 → S41). When it times out, after resetting the timer, it proceeds to the procedure for changing the used channel of the subsequent wireless relay network (S50: Y → S51 to S58).

[0071] Regarding the interfering radio wave, not only from the communication terminals 70 of other groups but also for the radio wave reception from other communication terminals 60b, 60c belonging to the group and other than the repeater 50, similar to the case of Embodiment 1, the determination is only conditional on the fact that "01" is not detected as the G-ID (S44). Also, if the interfering radio wave does not continue for a predetermined time (e.g., 1 sec) or more, the use channel of the wireless relay network is maintained, and the frequent repetition of the use channel change operation due to sudden interfering radio waves that do not affect the call too much is avoided, which is the same as in the case of Embodiment 1.

[0072] After the timeout, when changing the use channel of the wireless relay network, first, the current setting pair channels (CH1-L and CH1-H) of the own device (here, the communication terminal 60a) will be changed. However, in order to prevent unnecessary sounds from being reproduced and output when the channel switching of the reception demodulation unit RX11 is performed, the amplifier 63 is set to mute (S51).

[0073] Then, the current setting pair channels (CH1-H and CH1-L) of the reception demodulation unit RX11 and the modulation transmission unit TX11 are changed and set to the available pair channel selected based on the state information of each pair channel obtained by the immediate previous cycle scan by the reception demodulation unit RX12. That is, among the available pair channels detected by the reception demodulation unit RX12 in one cycle scan for the H band group in FIG. 3A immediately before the timeout, the available pair channel with the largest frequency separation from the non-available pair channel (here, CH2-H and CH2-L) is selected, and the current setting pair channels (CH1-H and CH1-L) of the reception demodulation unit RX11 and the modulation transmission unit TX11 are changed and set to the selected pair channels (CH2-H and CH2-L) (S52, S53). Here, the method of selecting the available pair channel with the largest frequency separation from the non-available pair channel is based on the procedures and algorithms described in Embodiment 1, and the description thereof is omitted here.

[0074] FIG. 15 shows a state in which the reception demodulation unit RX11 and the modulation transmission unit TX11 of the communication terminal 60a are reconfigured to the free pair channels (CH2-H and CH2-L). Since the communication terminal 60a has shifted to the pair channel of channel number CH2 and is no longer affected by the interfering radio waves from the communication terminal 70, but the repeater 50 and the communication terminals 60b and 60c still have the previously set used channels of the wireless relay network, the communication terminal 60a transmits the GID: "01" and the CCR to the repeater 50 to set the entire wireless relay network to the pair channel of channel number CH2.

[0075] Therefore, the communication terminal 60a will turn on the modulation transmission unit TX01 reconfigured to CH2-H and transmit the GID: "01" and the CCR. However, prior to transmission, it is necessary to perform carrier sense for the pair channel (CH2-L or CH2-H) using the reception demodulation unit RX01 (S54). In that case, since it has been confirmed in the immediately preceding round of scanning that the pair channel of channel number CH2 is in an idle state, the result of the carrier sense should be in an almost idle state and transmission should be possible. However, if interfering radio waves happen to have occurred in the pair channel of channel number CH2 after the round of scanning, the result will be in a busy state and transmission will be impossible.

[0076] Therefore, when the result of the carrier sense is in a busy state, the free pair channel with the second largest frequency separation from the non-free pair channel in the scan information table (channel number 9 in the scan information table) is selected and the carrier sense is re-executed (S55: N→S56→S53, S54). Note that the isolation degree is compared and determined with the interference radio wave flag set retroactively for the pair channel of the channel number in the busy state, and the free pair channel with the m-th largest isolation degree will be selected in the same way hereafter. However, generally, it is extremely rare to select a channel after the third one.

[0077] When the result of carrier sense is the idle state, as shown in Fig. 16, the communication terminal 60a turns on the modulation transmission unit TX11 and turns off the reception demodulation units RX11 and RX12, and transmits GID: "01" and CCR on the L-band side channel of the channel number CH2 in Fig. 3A that has been changed and set (S55 → S57). Also, by transmitting CCR, the mute setting of the amplifier 64 is released and the system returns to the standby state (S58).

[0078] Here, the transmission radio wave (channel number CH2, L-band group side) of the communication terminal 60a can be received only by the sequential scanning of the reception demodulation unit RX02 of the repeater 50. This is because the reception demodulation unit RX01 of the repeater 50 and the reception demodulation units RX21 and RX31 of the communication terminals 60b and 60c still remain on the channel of channel number CH1 and have different channel numbers, and the reception demodulation units RX22 and RX32 of the communication terminals 60b and 60c are performing a 27-channel sequential scanning, but it is a sequential scanning for the H-band group side channels, and only the reception demodulation unit RX02 of the repeater 50 is sequentially scanning the 27 channels on the L-band group side.

[0079] The execution procedure at that stage in the repeater 50 is shown in Fig. 17. First, in the repeater 50, in the standby state, the reception demodulation unit RX02 sequentially scans the 27 channels of the L-band group in Fig. 3A, and when a radio wave with a predetermined field strength or more is received, the sequential scanning is temporarily stopped on the received channel (S61~S63). Then, the system control unit 67 checks the data payload of the reception demodulation signal obtained from the reception demodulation unit RX02 and determines whether GID: "01" can be detected (S64, S65).

[0080] Here, if GID: "01" is not detected, the sequential scanning of the reception demodulation unit RX02 is restarted and the system returns to the standby state (S65 → S66 → S61), but if GID: "01" is detected, it is further confirmed whether CCR is detected (S65 → S67). When CCR is not detected, since GID: "01" is detected, it is a reception related to group communication from any of the communication terminals 60a, 60b, 60c within the group. Resume the cyclic scanning of the reception demodulation unit RX02, and while maintaining the current relay channels (CH1-L, CH1-H) of the reception demodulation unit RX02 and the modulation transmission unit TX01, switch the modulation transmission unit TX01 to the ON state to execute the relay operation of the voice call signal. When the reception ends, switch the modulation transmission unit TX01 to the OFF state and return to the standby state (S67→S68, S69→S61).

[0081] On the other hand, when GID: "01" is detected and further CCR is detected, change the settings of the channels of the reception demodulation unit RX01 and the modulation transmission unit TX01 to the pair channels (here CH2-L and CH2-H) related to the scan stop channels of the reception demodulation unit RX02 (S65→S67→S70). That is, as shown in FIG. 16, when the repeater 50 receives the CCR from the communication terminal (here 60a), the pair channels (CH2-H and CH2-L) set in the reception demodulation unit RX11 and the modulation transmission unit TX11 on the communication terminal 60a side are changed and set to the reception demodulation unit RX01 and the modulation transmission unit TX01 of the repeater 50 in a reverse relationship for transmission and reception.

[0082] FIG. 18 shows a state where the pair channels (CH2-L and CH2-H) are set in the reception demodulation unit RX01 and the modulation transmission unit TX01 of the repeater 50. At this stage, while the communication terminal 60a and the repeater 50 are set for transmission and reception using the pair channels of channel number CH2, the communication terminals 60b, 60c remain set for transmission and reception using the pair channels of channel number CH1, which is still the channel of the interfering radio wave. Therefore, the system control unit 53 of the repeater 50 causes the reception demodulation unit RX01 to execute carrier sense related to channel number CH2, and if it can be confirmed that it is in the idle state, transmit G-ID: "01" and CCR from the modulation transmission unit TX01 (S71, S72: Y→S73).

[0083] Note that even in the case of carrier sense in this situation, since it has been confirmed by the previous circuit scan by the reception demodulation unit RX12 of the communication terminal 60a that the paired channel of channel number CH2 is in an idle state, it should be in an idle state in most cases. However, if it happens to be in a busy state, the steps S10 to S15 in Embodiment 1 may be executed to perform the change setting of the used paired channel under the leadership of the repeater 50 (S71, S72 → S74).

[0084] FIG. 19 shows a state in which G-ID: "01" and CCR are transmitted from the repeater 50, and the transmission channel is the channel on the H band side of the channel number CH2 changed and set to the modulation transmission unit TX01. In that case, the communication terminal 60a receives those signals by the reception demodulation unit RX11. Since G-ID: "01" is detected from the data payload of the demodulated signal, the procedure proceeds from steps S41 to S44: Y in FIG. 14 to steps S45 and S46 and is processed in the same manner as normal group relay communication. Even if CCR is detected from the data payload, it is ignored, and the reception ends and the standby state is restored (S46 → S41).

[0085] On the other hand, in the communication terminals 60b and 60c, since the respective reception demodulation units RX21 and RX31 remain set to the channel of channel number CH1, they cannot receive the radio wave from the repeater 50 and will receive it during the circuit scan process of the respective reception demodulation units RX22 and RX32. And, in the communication terminal 60, the details of the execution procedure when there is no reception in the reception demodulation unit RXn1 and there is reception of radio waves only during the circuit scan process of the reception demodulation unit RXn2 are shown in FIG. 20 following step S42a in FIG. 14.

[0086] All the execution procedures in FIG. 20 correspond to steps S22 to S33 in FIG. 10 (operations of the wireless communication terminals 60a, 60b, and 60c) in Embodiment 1. When the radio wave transmitted from the repeater 50 is received during the scanning process of the reception demodulation unit RXn2, the scanning is stopped. When GID: "01" and CCR are detected from the data payload of the demodulated signal, each channel of the reception demodulation unit RXn1 and the modulation transmission unit TXn1 is set to be changed to the paired channel corresponding to the scanning stop channel of the reception demodulation unit RXn2 with the amplifier 64 in the mute setting.

[0087] As a result, the set channels of the reception demodulation units RX21 and RX31 and the modulation transmission units TX21 and TX31 in the communication terminals 60b and 60c are changed from the paired channels of channel number CH1 to the paired channels of channel number CH2 as shown in FIG. 21, and the paired channels used by the entire wireless relay network related to group communication are switched to the paired channels of channel number CH2 that are not affected by interfering radio waves.

[0088] Note that the wireless relay system of this Embodiment 2 can also be integrated with the wireless relay system of Embodiment 1, and the change of the used channel against interfering radio waves can be realized more adaptively.

[0089] <Applied paired channels> As the paired channels in each of the above embodiments, although 27 sets of paired channels (Figure 3A) in Table 3-2 and Table 3-4 on pages 1-5 and 1-6 of Part 1 of the above Non-Patent Document 1 are used, 52 sets of paired channels in Table 3-3 and Table 3-4 on pages 2-7 and 2-8 of Part 2 of the same document, 24 channels selected in ascending order and continuously from a total of 72 child unit channels in Table 3-2 on pages 11 to 13 of the above Non-Patent Document 2, and any combination of 24 continuously ascending parent unit (repeater) channels in Table 3-3 on pages 13 to 14, for a total of 24 sets of paired channels, and 10 sets of paired channels described on page 1-19 of Part 1 of "Wireless Equipment / Standard Specifications of Digital Simple Wireless Stations": RCR STD-T98 Version 2.0, 10 sets of paired channels described on page 2-24 of Part 2, 10 sets of paired channels described on page 3-19 of Part 3, etc. are also applicable. Note that since the standard specifications related to the above Non-Patent Document 2 are for wireless stations of land mobile services with an antenna power of 1 mW or less, carrier sense is not required.

Industrial Applicability

[0090] The present invention can be applied to a wireless relay network system using a semi-duplex method with paired channels that can be used in wireless equipment for specific low-power wireless stations / wireless telephones, wireless equipment for wireless stations of land mobile services (for work communication) with an antenna power of 1 mW or less, and wireless equipment of digital simple wireless stations.

Explanation of Signs

[0091] 50…Wireless repeater, 51, 52…Antennas, 53…System control unit, 54…Operation unit, 55…Various indicator lamps, RX01…Receiving and demodulating unit, RX02…Receiving and demodulating unit (channel scanning), TX01…Modulating and transmitting unit, 60 (60a, 60b, 60c)…Wireless communication terminal, 61…Antenna, 62…Antenna switching unit, 63…Amplifier, 64…Speaker (or earphone), 65…Microphone, 67…System control unit, 68…Operation unit, 69…Liquid crystal display unit, RXn1…Receiving and demodulating unit, RXn2…Receiving and demodulating unit (channel scanning), TXn1…Modulating and transmitting unit, 70…Wireless communication terminal belonging to other groups.

Claims

1. A wireless relay system comprising a wireless repeater and a plurality of wireless communication terminals forming a single group, which selects one pair channel from a group of two channels (hereinafter referred to as "pair channels") that can be used for the upstream and downstream waves related to communication between the wireless repeater and each wireless communication terminal in a standard specification formulated based on the Radio Law Enforcement Regulations and the Wireless Equipment Regulations, and performs group communication between the wireless communication terminals in a half-duplex manner, wherein the wireless repeater, is provided with a reception demodulation unit A, a reception demodulation unit B, a modulation transmission unit C, and a control unit for controlling them. The one pair channel is set for the reception demodulation unit A and the modulation transmission unit C, while the reception demodulation unit B scans a group of channels that can be used as the reception channel of the reception demodulation unit A to search for an available channel. In the standby / reception mode, the reception demodulation unit A and the reception demodulation unit B are turned on, and the modulation transmission unit C is turned off. When group identification information related to the group is detected and confirmed from the demodulation signal of the reception demodulation unit A, it switches to the relay mode. In the relay mode, the modulation transmission unit C is turned on, and the carrier wave of the transmission channel is modulated and transmitted with the demodulation signal output by the reception demodulation unit A. In addition, in the standby / reception mode, when the reception demodulation unit A receives radio waves with a certain electric field strength or more for a predetermined time or more and cannot detect and confirm the group identification information from its demodulation signal, the set pair channel of the reception demodulation unit A and the modulation transmission unit C is changed to the pair channel related to the available channel searched by the reception demodulation unit B, and the modulation transmission unit C is turned on to transmit the group identification information and the channel change request information, wherein each wireless communication terminal, It is provided with a reception demodulation unit D, a reception demodulation unit E, a modulation transmission unit F, and a control unit for controlling them. In the reception demodulation unit D and the modulation transmission unit F, the pair channels set in the reception demodulation unit A and the modulation transmission unit C on the wireless repeater side are set in an inverse relationship for transmission and reception. On the other hand, the reception demodulation unit E scans a group of channels that can be used as the reception channels of the reception demodulation unit D to search for an empty channel. In the standby / reception mode, the reception demodulation unit D and the reception demodulation unit E are in the ON state, and the modulation transmission unit F is in the OFF state, and the demodulated signal output by the reception demodulation unit D is voice-played. In the transmission mode, the reception demodulation unit D and the reception demodulation unit E are in the OFF state, and the modulation transmission unit F is in the ON state, and the carrier wave of the transmission channel of the modulation transmission unit F is modulated with the input voice signal and transmitted. In addition, in the standby / reception mode, when the reception demodulation unit E receives the group identification information and the channel change request information transmitted by the wireless repeater side during its scanning process, the reception channel and the channel in a paired channel relationship with it are respectively set in the reception demodulation unit D and the modulation transmission unit F. A wireless relay system characterized by this.

2. In the wireless repeater, when the reception demodulation unit A receives a radio wave with a certain field strength or more from which the group identification information cannot be confirmed from its demodulated signal for a predetermined time or more, and when a plurality of empty paired channels are detected during one scanning process by the reception demodulation unit B immediately before the detection of the reception for the predetermined time or more, the empty paired channel with the largest frequency separation from the non-empty paired channel is re-set in the reception demodulation unit A and the modulation transmission unit C, and the group identification information and the channel change request information are transmitted from the modulation transmission unit C. The wireless relay system according to claim 1.

3. In the wireless repeater, when performing carrier sense using the reception demodulation unit A prior to the transmission operation of the modulation transmission unit C, the empty paired channels are selected in descending order of the frequency separation from the non-empty paired channels to perform carrier sense. The wireless relay system according to claim 2.

4. A wireless relay system comprising a wireless relay device and a plurality of wireless communication terminals forming a group, and selecting one pair of channels (hereinafter referred to as "pair channels"), which are available for the uplink and downlink in the communication between the wireless relay device and each wireless communication terminal in the standard specifications formulated based on the Radio Law Enforcement Regulations and the Radio Equipment Regulations, to perform group communication between the wireless communication terminals in a half-duplex mode. The wireless relay device is provided with a reception demodulation unit A, a reception demodulation unit B, a modulation transmission unit C, and a control unit for controlling them. The one pair of channels is set for the reception demodulation unit A and the modulation transmission unit C, while the reception demodulation unit B scans the channel group available for use as the reception channel of the reception demodulation unit A. In the standby / reception mode, the reception demodulation unit A and the reception demodulation unit B are in the ON state, and the modulation transmission unit C is in the OFF state. When the group identification information related to the group is detected and confirmed from the demodulation signal of the reception demodulation unit A, it switches to the relay mode. In the relay mode, the modulation transmission unit C is turned on, and the carrier wave of the transmission channel is modulated and transmitted with the demodulation signal output by the reception demodulation unit A. In addition, in the standby / reception mode, when the reception demodulation unit B receives the group identification information and the channel change request information transmitted by any of the wireless communication terminals during its scanning process, the reception channel and the channel in the pair channel relationship with it are respectively set for the reception demodulation unit A and the modulation transmission unit C, and the group identification information and the channel change request information are transmitted from the modulation transmission unit C. Each of the wireless communication terminals It is provided with a reception demodulation unit D, a reception demodulation unit E, a modulation transmission unit F, and a control unit for controlling them. In the reception demodulation unit D and the modulation transmission unit F, the pair channels set in the reception demodulation unit A and the modulation transmission unit C on the wireless repeater side are set in a reverse relationship for transmission and reception. On the other hand, the reception demodulation unit E scans the group of channels that can be used as the reception channels of the reception demodulation unit D in a cyclic manner and searches for available channels. In the standby / reception mode, the reception demodulation unit D and the reception demodulation unit E are in the ON state, and the modulation transmission unit F is in the OFF state, and the demodulated signal output by the reception demodulation unit D is played back as audio. In the transmission mode, the reception demodulation unit D and the reception demodulation unit E are in the OFF state, and the modulation transmission unit F is in the ON state, and the carrier wave of the transmission channel of the modulation transmission unit F is modulated with the input audio signal and transmitted. In addition, in the standby / reception mode, when the reception demodulation unit D receives radio waves with a certain electric field strength or more for a predetermined time or more and cannot detect the group identification information from the demodulated signal, the set pair channels of the reception demodulation unit D and the modulation transmission unit F are changed to the pair channels related to the available channels searched by the reception demodulation unit E, and the modulation transmission unit F is turned on to transmit the group identification information and the channel change request information. On the other hand, when the reception demodulation unit E receives the group identification information and the channel change request information transmitted from the wireless repeater side during the cyclic scanning process, the reception channel and the channel in the pair channel relationship with it are set in the reception demodulation unit D and the modulation transmission unit F, respectively. A wireless relay system characterized by the above.

5. In the wireless communication terminal, when the reception demodulation unit D receives radio waves with a certain electric field strength or more for a predetermined time or more and cannot confirm the group identification information from the demodulated signal, when a plurality of available pair channels are detected in one cyclic scanning process by the reception demodulation unit E immediately before the detection of the reception for the predetermined time or more, the available pair channel with the largest frequency separation from the non-available pair channel is changed and set in the reception demodulation unit D and the modulation transmission unit F, and the group identification information and the channel change request information are transmitted from the modulation transmission unit F. The wireless relay system according to claim 4, wherein this is done.

6. The wireless relay system according to claim 5, wherein, in the wireless communication terminal, when performing carrier sense using the reception demodulation unit D prior to the transmission operation of the modulation transmission unit F, an available paired channel is selected in descending order of the frequency separation degree with respect to a non-available paired channel, and carrier sense is performed.

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