JP2013059133A - Radio communication device and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device and a radio communication method of a new digital cordless telephone set that can avoid harmful radio wave interference with a control channel important for the operation of a PHS and can increase frequency utilization efficiency as a speech channel.SOLUTION: The invention receives a frequency band allocated to a digital cordless telephone set and a frequency band allocated to a PHS, measures reception electric field strength of a received signal to output it, monitors output of the reception electric field strength of a signal received continuously for a certain time period, determines whether or not there is interference by a signal transmitted by a PHS fixed station measuring the time width and frequency of appearance of the reception electric field strength equal to or more than a prescribed threshold, and if it has been determined there is interference, sets a frequency band and slot timing to be used so that the interference will be avoided, and transmits communication data at the set frequency band and slot timing.

Description

  The present invention relates to a wireless communication apparatus and a wireless communication method applicable to a digital cordless telephone.

  In Japan, 1893.5 MHz to 1906.1 MHz are allocated as frequency bands that can be used by digital cordless telephones, as shown in FIG. The frequency band adjacent to the frequency band is used by a public PHS (hereinafter referred to as “public PHS”). Here, the public PHS is a form that is connected to a PHS base station outdoors and used as mobile communication. The self-supporting PHS (hereinafter referred to as “self-supporting PHS”) is a form used as mobile communication between a base phone and a handset of a PHS cordless telephone.

  Here, at present, only the PHS system uses the frequency band of 1893.5 MHz to 1906.1 MHz. In the PHS system, TDMA (Time Division Multiple Access) / TDD (Time Division) is configured to include 8 slots (4 slots for uplink and 4 slots for downlink) in one frame of 5 ms cycle. Duplex: Time Division Duplex) is adopted. Usually, one slot pair is assigned as a control channel, and three slot pairs are assigned as a call channel.

  In the PHS system, the control signal is intermittently transmitted from the base station. Specifically, a public PHS base station periodically transmits a control signal at a period of 120 ms (24 frame period).

  In the self-supporting PHS, the fixed station intermittently transmits a control signal at an arbitrary time position in increments of 5 ms with an interval of 125 ms or more and 300 ms or less. In this way, in a private PHS, one frame is a 5 ms cycle like a public PHS. However, a fixed station of a private PHS does not necessarily transmit a control signal at regular intervals. The transmission is performed after 125 ms or at a timing obtained by adding a multiple of 5 ms to 125 ms.

  In addition, as shown in FIG. 1, the frequency of the control channel of the PHS system is one of 1906.650 MHz, 1907.150 MHz, and 1907.750 MHz for each operator since June 2012 in the public PHS. In the private PHS, frequencies of 1898.450 MHz and 1900.250 MHz are fixedly assigned.

  In addition, the PHS communication channel is allocated by request / response on the control channel. For example, in the private PHS, as shown in FIG. 1, all 40 frequencies are secured.

  Therefore, in the future, as a system that uses the above frequency band of 1893.5 MHz to 1906.1 MHz, as shown in FIG. 1, a digital cordless telephone system (hereinafter referred to as a DECT system) conforming to the DECT (Digital Enhanced Cordless Communications) standard. To be added).

  The DECT system, which is being studied as a new system, employs a TDMA / TDD system that includes 24 slots (12 slots for the uplink and 12 slots for the downlink) in one frame of 10 ms period. Yes. In addition, at least one control channel slot is provided, and both the control channel and the communication channel are transmitted and received at a frame period of 10 ms. Further, each frequency / slot position is arbitrary, and the frequencies are considered in all five frequencies as shown in FIG.

  However, the control signal of the public PHS (signal transmitted / received between the PHS base station and the PHS terminal in order to control a call between the PHS base station and the PHS terminal) is 1906.1 MHz as shown in FIG. Since it is considered to move to an adjacent frequency channel, the harmonic component of the radio wave used by the DECT system may interfere with the control signal. When the DECT system is added, the DECT system and the public PHS Coexistence becomes a problem.

  Therefore, in order to reduce the interference between the DECT system and the call between the PHS base station and the PHS terminal, the harmonic component of the radio wave used by the DECT system is converted into a control signal transmitted and received between the PHS base station and the PHS terminal. It is particularly important not to interfere.

  Here, the following (patent documents 1-5) exist as an example of the conventional interference prevention technique.

  For example, in the technique of (Patent Document 1), when there is a possibility that interference occurs in two wireless systems in which the frequency bands are close to each other, it is detected whether interference has occurred and the use frequency is influenced by the interference. The frequency range is estimated to be small.

  In the technology of (Patent Document 2), when another digital cordless telephone device is in a call in the vicinity, the transmission / reception timing of this telephone device is detected, and transmission / reception is performed at a slot position that does not interfere with this timing. .

  In the technique of (Patent Document 3), when the self-occupied slot position and the other-device-occupied slot position overlap, the self-occupied slot position is changed to the leading empty beacon slot position.

  In the technique of (Patent Document 4), when an information block is transmitted from a transmitter to a receiver using an available access slot and the information block is properly received without collision at the receiver, other information is transmitted. It also sends information about blocks.

  In the technique of (Patent Document 5), a standby channel for avoiding asynchronous interference is prepared in advance and notified to the mobile device together with a communication signal, and when asynchronous interference is detected, the channel is switched to the standby channel. .

JP 2002-353878 A JP-A-4-286431 JP 2007-243749 A JP 2001-169331 A JP 7-67169 A

  However, according to the above prior art (for example, Patent Documents 1 to 5 and the like), in order to improve the communication efficiency of the DECT system, it is necessary to accurately predict the transmission timing of the control signal. Thus, since the PHS control signal is transmitted every 5 ms or at intervals of multiples of 5 ms, there is a problem that it is difficult to determine whether the signal detected by the receiving unit in the DECT terminal is a PHS control signal.

  Further, in the above prior art, when there is another DECT terminal that is not synchronized with the own system nearby, the other DECT system terminal also transmits a control signal every 10 ms. Since it is a multiple of 5 ms, there is a problem that it is difficult to distinguish between a PHS control signal and a DECT control signal.

  Specifically, there are two types of radio interference: interference on the control channel and interference on the communication channel. Especially when PHS and DECT are used in the same frequency band, harmful radio interference is suppressed. A mechanism to do this is required.

  With respect to the control channel, the PHS system is used for call channel assignment and incoming call notification, and when the control channel communication is interrupted, a serious problem that the system stops is generated. Furthermore, since the frequency of the PHS control channel is fixed in advance as shown in FIG. 1, even if there is a continuous disturbance in the frequency of the control channel, the frequency is changed to avoid it. There was a problem that it was not possible.

  As for the communication channel, PHS and DECT use different radio wave bandwidths, modulation / demodulation methods, and transmission speeds, and the same method allows efficient interference avoidance. The best interference avoidance method is that the radio waves cannot be judged and the radio waves are not emitted at the same frequency, and the utilization efficiency of frequency resources is deteriorated. In particular, due to the difference in occupied bandwidth, as shown in FIG. 1, DECT occupies 6 times the frequency of PHS. Therefore, if DECT uses one frequency, PHS cannot use 6 frequencies. On the other hand, if PHS uses one frequency, DECT cannot use 6 times the frequency of PHS. Further, as shown in FIG. 1, a frequency for a public PHS control channel is allocated in the immediate vicinity of the frequency allocated to the digital cordless telephone. Depending on the intensity of unnecessary emission of PHS and DECT radio waves, There was also a possibility of obstructing the operation of PHS.

  The present invention has been made in view of the above problems, and determines whether or not there is interference by a control channel or a communication channel of an adjacent PHS, thereby avoiding harmful radio interference to a control channel important for PHS operation. It is an object of the present invention to provide a new digital cordless telephone radio communication apparatus and radio communication method that can increase frequency use efficiency as a call channel.

  In order to solve the above-described problems and achieve the above-described object, the present invention provides a radio that receives a signal having a plurality of time slots that are time-division multiplexed in a frequency band that overlaps the PHS frequency band as a frame. There is a communication device that determines whether or not the received signal is interference due to a control channel of a private PHS fixed station, and the determination means causes interference due to the control channel of the private PHS fixed station In this case, there is provided control means for disabling all time slots in a frequency band overlapping with a frequency band used by the control channel of the private PHS.

  According to the present invention, a PHS control signal and a DECT control signal can be discriminated, and interference with an existing PHS call can be reduced, and harmful radio interference to a control channel important for PHS operation can be avoided. Thus, a new digital cordless telephone radio communication apparatus and radio communication method capable of improving the frequency utilization efficiency as a call channel can be obtained.

The figure which shows an example of the zone | band of a PHS control signal and a DECT spurious The block diagram which shows an example of the whole structure of this radio | wireless communication apparatus The figure which shows an example of interference with a public PHS base station The figure which shows an example of interference with a private PHS fixed station The figure which shows an example of interference with another DECT main | base station The figure which shows an example of a frequency slot table Flowchart showing an example of processing of the wireless communication device Flowchart showing an example of processing of the wireless communication device

  According to a first aspect of the present invention, a wireless communication apparatus receives a frequency band assigned to a digital cordless telephone that communicates with a base station using a plurality of time-division multiplexed time slots as a frame, and a frequency band assigned to a PHS. A reception unit that measures and outputs the received electric field strength of the received signal, and monitors the output of the received electric field strength of the signal that is continuously received by the receiving unit for a certain period of time. By measuring the time width and frequency at which the received electric field strength appears, interference type determination means for determining whether there is interference due to the signal transmitted from the fixed station of the PHS, and the interference type determination means by the interference type determination means When it is determined that there is interference due to a signal transmitted from a fixed station, the digital cordless telephone is used to avoid the interference A communication slot setting unit that sets a wave number band and a slot timing, and a transmission unit that transmits communication data using the frequency band and the slot timing allocated by the communication slot setting unit are provided. . With this configuration, communication channels can be segregated according to frequency and time timing, and even if the used frequency band is shared with the PHS, radio interference with the PHS can be prevented, so that the control channel is important for PHS operation. The harmful radio wave interference can be avoided, and the frequency use efficiency as a call channel can be improved.

  According to a second aspect of the present invention, there is provided the wireless communication apparatus according to the first aspect, wherein the interference type determining means includes a frequency of a signal in which a received electric field strength that exceeds a predetermined threshold appears, and a time slot in which the signal is received. And the signal is detected in a time width of one slot or two slots while monitoring at a period of at least 300 ms, and after that, a signal having substantially the same received electric field strength is 120 ms or more. If it appears in a cycle or at least once, it is determined that there is interference from the PHS control channel. With this configuration, by monitoring the frequency, slot number, and frame number of a signal having a received electric field strength equal to or higher than a predetermined threshold, the time width and frequency at which the received electric field strength equal to or higher than the predetermined threshold appears can be measured. It is possible to determine whether or not there is interference from the PHS control channel.

  According to a third aspect of the present invention, there is provided the wireless communication apparatus according to the first aspect, wherein the interference type determining means includes a frequency of a signal in which a received electric field strength exceeding the predetermined threshold appears, and a time at which the signal is received. The slot number corresponding to the slot is monitored, and the signal is detected in a time width corresponding to one slot or two slots while monitoring at a period of at least 300 ms, and thereafter, a signal having substantially the same received electric field strength has a period of 5 ms. If it appears at a frequency of, it is determined that there is interference due to the PHS communication channel. With this configuration, by monitoring the frequency, slot number, and frame number of a signal having a received electric field strength equal to or higher than a predetermined threshold, the time width and frequency at which the received electric field strength equal to or higher than the predetermined threshold appears can be measured. It is possible to determine whether or not there is interference due to the PHS communication channel.

  According to a fourth aspect of the present invention, there is provided the wireless communication apparatus according to the first aspect, wherein the communication slot setting means determines that there is interference from a PHS control channel by the interference type determining means. When the frequency band of the control channel of the PHS received by the receiving unit is a frequency band including the control channel of the private PHS, all the times in the frequency band of the digital cordless telephone corresponding to the frequency band of the control channel of the private PHS The slot is set so that it cannot be used. With this configuration, an available frequency band and slot timing that do not interfere with the control channel of the private PHS can be set.

  A wireless communication device according to a fifth aspect of the present invention is the wireless communication device according to the invention, wherein the communication slot setting means determines that there is interference due to a PHS communication channel by the interference type determination means. It is characterized in that all the time slots in the frequency band of the digital cordless telephone corresponding to the frequency band of the control channel are set to be unusable. With this configuration, an available frequency band and slot timing that do not interfere with the PHS communication channel can be set.

  The wireless communication apparatus of the sixth invention is set by the communication slot setting means in the wireless communication apparatus of the invention when the interference type determining means determines that there is interference due to a PHS control channel or a speech channel. And a control unit for controlling to notify a wireless communication device of another digital cordless telephone by outputting a frequency band and slot timing used by the digital cordless telephone to the transmitting unit. It is. With this configuration, for example, an available frequency band that does not interfere with a PHS control channel or a communication channel with respect to a registered child device if it is a parent device, and a registered parent device if it is a child device, and The slot timing can be notified to the wireless communication device of another digital cordless telephone that will perform communication from the transmitter in advance.

  A wireless communication method according to a seventh aspect of the invention is a wireless communication method executed in a wireless communication device of a digital cordless telephone, and is a digital cordless telephone that communicates with a base station using a plurality of time-division multiplexed time slots as frames. A reception step of receiving the allocated frequency band and the frequency band allocated to the PHS, measuring and outputting the received electric field strength of the received signal, and reception of the signal received for a predetermined time in the reception step Interference type determination step of determining whether or not there is interference due to a signal transmitted from a fixed station of PHS by monitoring the output of the electric field strength and measuring the time width and frequency at which the received electric field strength exceeding a predetermined threshold appears. In the interference type determination step, it is determined that there is interference due to a signal transmitted from the fixed station of the PHS. The communication slot setting step for setting the frequency band and slot timing used by the digital cordless telephone so as to avoid the interference, and the communication data by the frequency band and the slot timing assigned in the communication slot setting step. And a transmission step of transmitting. With this configuration, communication channels can be segregated according to frequency and time timing, and even if the used frequency band is shared with the PHS, radio interference with the PHS can be prevented, so that the control channel is important for PHS operation. The harmful radio wave interference can be avoided, and the frequency use efficiency as a call channel can be improved.

Embodiments of a wireless communication device and a wireless communication method for a digital cordless telephone according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Embodiment.
[1. Configuration of wireless communication apparatus]
First, the configuration of the wireless communication apparatus will be described with reference to FIG. 1 and FIGS. 2 to 6 again. FIG. 2 is a block diagram showing an example of the overall configuration of the wireless communication apparatus, and conceptually shows only the portion related to the present invention in the configuration.

  In FIG. 2, reference numeral 100 denotes a wireless communication apparatus, reference numeral 101 denotes a receiving unit, reference numeral 102 denotes interference type determination means, reference numeral 103 denotes communication slot setting means, reference numeral 104 denotes a frequency slot table, Reference numeral 105 denotes a control unit, and reference numeral 106 denotes a transmission unit.

  In FIG. 2, a receiving unit 101 receives a frequency band assigned to a digital cordless telephone that communicates with a base station using a plurality of time-division multiplexed time slots as a frame, and a frequency band assigned to a PHS, It is means for measuring and outputting the received electric field strength of the received signal.

  Here, the digital cordless telephone is a DECT system, and the frequency band allocated to the digital cordless telephone means a frequency band of 1893.5 MHz to 1906.1 MHz as shown in FIG. In addition, as shown in FIG. 1, the frequency band allocated to PHS (for example, private PHS, public PHS, etc.) is a frequency band of 1893.5 MHz to 1906.1 MHz and harmonics close to 1906.1 MHz. It means a frequency band that includes components. In the case of public PHS, the frequency used by the PHS base station (fixed station) to transmit a control signal is one of 1906.65 MHz, 1907.15 MHz, and 1907.75 MHz for each operator after June 2012. Is fixedly assigned. In the case of self-supporting PHS, the frequency used to transmit the control signal is assigned either 1898.45 MHz or 1900.25 MHz.

  Returning to FIG. 2, the interference type determination unit 102 is a signal continuously received by the reception unit 101 for a certain period of time at the time of activation or at any time (for example, before starting communication or in a state of waiting for communication start). Means for determining whether there is interference due to a signal transmitted from a fixed station of PHS by monitoring the output of the received electric field strength and measuring the time width and frequency at which the received electric field strength exceeding a predetermined threshold appears It is.

  Specifically, the interference type determination unit 102 monitors a signal having a received electric field strength equal to or greater than a predetermined threshold while switching the frequency and time slot. When a signal having a received electric field strength equal to or greater than a predetermined threshold is detected, the frequency of the signal, the slot number corresponding to the time slot in which the signal is detected, and the frame number corresponding to the frame at that time Monitor and record the frequency, slot number, and frame number in memory. When monitoring is performed for a period of at least 300 ms, for example, when a signal is detected with a time width of one slot or two slots, and a signal having substantially the same received electric field strength appears at a frequency of 5 ms period thereafter, the PHS communication channel It is determined that there is interference due to. If signals having substantially the same received electric field strength appear thereafter with a frequency of 120 ms or more, or appear only once, it is determined that there is interference from the PHS control channel.

  Here, the call channel means a channel used for a call assigned by a control signal request / response on the control channel. The control channel means a channel used when transmitting / receiving a control signal between the base station and the terminal in order to control a call between the base station and the terminal.

  Hereinafter, referring to FIG. 3 to FIG. 5, examples of the interference with the public PHS base station, the interference with the private PHS fixed station, and the interference with other DECT base units, which are determined by the interference type determination unit 102. explain. FIG. 3 is a diagram illustrating an example of interference with a public PHS base station. FIG. 4 is a diagram illustrating an example of interference with a private PHS fixed station. FIG. 5 is a diagram illustrating an example of interference with another DECT base unit.

  As shown in FIG. 3, the interference type discrimination means 102 has a frequency of a signal having a received electric field strength equal to or greater than a predetermined threshold and a slot number (for example, S4, S5, etc.) corresponding to the time slot in which the signal is received. ) And the frame number (for example, 1 frame, 2 frames, etc.) corresponding to the frame, and if a signal having a received electric field strength equal to or higher than a predetermined threshold is detected, the frequency, slot number, and frame of the signal are detected. Record the number in memory. When the reception frequency is set to the frequency F8 shown in FIG. 1 including the frequency (for example, 1906.65 MHz) used by the public PHS base station for control signal transmission, the time width for one slot or two slots (for example, in S4) Corresponding to one slot or two slots corresponding to S4 and S5), a signal having a received electric field strength equal to or greater than a predetermined threshold value is detected, and then a signal having substantially the same received electric field strength in a period of approximately 120 ms. If it is detected regularly, there is a high possibility that there is a public PHS base station nearby. As shown in FIG. 3, since the DECT frame period is an integral multiple of the PHS frame period, the control signal transmitted by the public PHS base station at an integral multiple of the frame period (5 ms × 24 = 120 ms) is synchronous / asynchronous. Regardless, DECT is always detected in a time slot having the same positional relationship.

  A PHS terminal must receive a control signal issued by a public PHS base station, but if there is a DECT master unit and a slave unit nearby, the spurious component of the communication signal between the DECT master unit and the slave unit interferes with the reception of the PHS terminal. May give. When the DECT master unit detects the signal that appears at the frequency at the frequency F8 shown in FIG. 1, it is determined that the spurious component of the communication signal between the DECT master unit and the slave unit interferes with the PHS control signal.

  Also, as shown in FIG. 4, when detecting interference with a private PHS fixed station, the interference type determination unit 102 receives a frequency of a signal having a received electric field strength equal to or greater than a predetermined threshold, and the signal is received. A signal having a received electric field strength equal to or higher than a predetermined threshold by monitoring a slot number (eg, S4, S16, etc.) corresponding to the time slot and a frame number (eg, 1 frame, 2 frames, etc.) corresponding to the frame. Is detected, the frequency, slot number, and frame number of the signal are recorded in the memory. When the reception frequency is set to a frequency (for example, frequency F3 including 1898.45 MHz or frequency F4 including 1900.25 MHz as shown in FIG. 1) used by the private PHS fixed station for control signal transmission, A signal having a received electric field strength equal to or greater than a predetermined threshold is detected with a time width of two slots (for example, one slot corresponding to S4 or two slots corresponding to S4 and S5). It is at the same level as the first signal at any time position (125 ms, 130 ms, or 125 ms plus a multiple of 5 ms) at intervals of 125 ms or more after detection and in increments of 5 ms. When a signal having a received electric field strength is detected, there is a high possibility that a fixed station of a private PHS exists nearby. When the DECT master unit detects the signal appearing at the frequency at the frequency F3 or F4 shown in FIG. 1, it is determined that the communication signal between the DECT master unit and the slave unit interferes with the self-supported PHS control signal.

  FIG. 5 shows a case where interference with another DECT master unit is detected. Also in this case, the interference type discriminating means 102 corresponds to the frequency of a signal having a received electric field strength equal to or greater than a predetermined threshold, the slot number (for example, S5) corresponding to the time slot in which the signal is received, and the frame. The frame number (for example, 1 frame, 2 frames, etc.) is monitored, and when a signal having a received electric field strength exceeding a predetermined threshold is detected, the frequency, slot number, and frame number of the signal are recorded in the memory. To do. As shown in FIG. 5 (a), while monitoring is continued for 300 ms, the time width for one slot or two slots (for example, the time width for one slot corresponding to S5 shown in FIG. 5 (a)). When a signal having the same received electric field strength is detected every time at a frequency of 10 ms (for example, a 10 ms cycle from S5 to S5) after that, the signal is estimated to be a DECT control signal. It is determined that there is interference due to the communication channel of the DECT terminal.

  Even if the period is slightly different from other DECT terminals, while continuing to monitor the signal as shown in FIG. 5B, the time width of one slot or two slots (for example, Signal is detected at a frequency of two slots corresponding to S4 and S5), and thereafter when the signal having substantially the same received electric field strength is detected every time at a frequency of approximately 10 ms period (S5 of the next frame) It is estimated that the signal is a DECT control signal, and it is determined that there is interference due to the communication channel of another DECT terminal.

  In this manner, DECT signals transmitted by other DECT master units affect time slots having the same positional relationship in DECT at all times regardless of the period match / period mismatch. As for the interference of the DECT communication channel, the same DECT method allows the use of various efficient interference avoidances because the radio wave bandwidth, modulation / demodulation method, and transmission speed are the same.

  Returning to FIG. 2, the communication slot setting unit 103 of the digital cordless telephone uses a frequency used by the digital cordless telephone when the interference type determining unit 102 determines that there is interference due to a signal transmitted from a fixed station of PHS. It is a means for setting the bandwidth and slot timing.

  Specifically, the slot setting unit 103, when it is determined by the interference type determining unit 102 that there is interference due to the control channel of the public PHS, the slot number (for example, FIG. 3 and S4 and S5) and a slot number 2.5 ms, 5 ms, or 7.5 ms away from the slot number (for example, as shown in FIG. 3, S10 and S11 in the + 6th slot, The time slots of S16 and S17 of the + 12th slot or S22 and S23 of the + 18th slot are disabled. The frequency used in this way is not changed (that is, in the frequency band of 1893.5 MHz to 1906.1 MHz), and other than the slot in which the slot timing to be used is disabled (for example, as shown in FIG. 3, slots S1 to S3 , S6 to S9, S12 to S15, S18 to S21, S24, etc.).

  In addition, when the interference type determining unit 102 determines that there is interference due to the control channel of the private PHS, the communication slot setting unit 103 is a digital cordless telephone corresponding to the frequency band of the control channel of the private PHS as shown in FIG. All the time slots in the frequency band (that is, all the time slots S1 to S24 having the frequencies of 1898.450 MHz and 1900.250 MHz) are disabled. That is, in this case, as frequency bands and slot timings used for communication of the digital cordless telephone, all slots S1 to S24 of frequencies within the frequency band of 1893.5 MHz to 1906.1 MHz excluding the frequencies of 1898.450 MHz and 1900.250 MHz are used. Set.

  In addition, when the interference type determining unit 102 determines that there is interference due to the PHS communication channel, the communication slot setting unit 103 uses a digital cordless telephone corresponding to the frequency of the control channel of the private PHS as shown in FIG. The frequency band and slot timing (ie, 1898) used by the digital cordless telephone so as to disable all time slots in the frequency band (ie, all time slots S1 to S24 at frequencies of 1898.450 MHz and 1900.250 MHz). All slots S1 to S24) of frequencies within a frequency band of 1893.5 MHz to 1906.1 MHz excluding frequencies of 450 MHz and 1900.250 MHz are set.

  The frequency slot table 104 is a means for recording setting contents indicating the frequency band and slot timing used by the digital cordless telephone set by the communication slot setting means 103.

  Here, an example of the frequency slot table 104 will be described with reference to FIG. As shown in FIG. 6, the frequency slot table 104 has a frame number for each monitor frequency (for example, when measuring for a fixed time of 300 ms, the frame number is 1 to 30 because one frame is 10 ms in DECT). , Slot numbers (for example, since 24 time slots are included in one frame in DECT, the slot numbers are S1 to 24) are stored in the storage device in association with each other. The frequency slot table 104 is a time width in which the interference type discriminating unit 102 monitors the output of the received electric field strength of the signal continuously received by the receiving unit 101 for a predetermined time, and the received electric field strength exceeding a predetermined threshold appears. It is also used when measuring frequency.

  Returning to FIG. 2, the control unit 105 is a unit that controls the entire radio communication apparatus 100, and when the interference type determination unit 102 determines that there is interference due to the PHS control channel or the communication channel, the communication slot The frequency band used by the digital cordless telephone set by the setting means 103 and the slot timing (that is, the setting contents recorded in the frequency slot table 104) are output to the transmitting unit 106, so that wireless communication of other digital cordless telephones is performed. It is means for controlling to notify the apparatus.

  The transmitting unit 106 is a unit that transmits communication data using the frequency band and slot timing assigned by the communication slot setting unit 103.

Above, description of an example of the whole structure of this radio | wireless communication apparatus is finished.
[2. Processing of wireless communication device]
Next, an example of processing in the radio communication apparatus according to the present embodiment configured as described above will be described in detail below with reference to FIGS. 1, 6, 7 and 8 again. FIGS. 7 and 8 are flowcharts showing an example of the processing of the wireless communication apparatus. FIG. 7 shows the first half of the processing, and FIG. 8 shows the second half of the processing.

  As shown in FIG. 7, first, the receiving unit 101 performs a process of determining whether or not there is interference at the time of activation or at any time (for example, before starting communication or when waiting for communication start). In order to execute, the reception frequency is set to the frequency channels F1 to F8 shown in FIG. 1 (step SA-1).

  Here, as shown in FIG. 1, the frequency allocated for DECT includes frequency channel F1, centering on 1895.616 MHz, frequency channel F2, centering on 1897.344 MHz, and frequency centering on 1899.072 MHz. There is a channel F3, a frequency channel F4 centered on 190.800 MHz, and a frequency channel F5 centered on 1902.528 MHz. Further, in FIG. 1, as frequency channels that may generate spurious when these frequencies are used in DECT, a plurality of frequency channels having centers at intervals of the center frequency of F5 from 1902.528 MHz to 1.728 MHz are F6, F7, and F8. It is defined as The frequency to be determined is a range in which frequency channels F6, F7, and F8 that may cause spurious are added in addition to the frequency channels F1 to F5 used for communication. In addition, when the control signal of the private PHS is transmitted at 1898.450 MHz, it can be received when the frequency channel F3 is monitored, and when it is transmitted at 1900.250 MHz, it is received when the frequency channel F4 is monitored. Is possible. When the public PHS control signal is transmitted at 1906.65 MHz, it can be received when the frequency channel F8 is monitored.

  Then, the control unit 105 sets a monitoring time (for example, a fixed time of 300 ms or more) (step SA-2), and initializes the frame number and slot number in the frequency slot table 104 as shown in FIG. Step SA-3).

  Then, the reception unit 101 uses the monitor frequency set in step SA-1 and the designated slot (for example, slot S1 among all slots S1 to 24) for the monitor time set in step SA-2. ), And the received electric field strength of the received signal is measured and output (step SA-4).

  Then, the interference type determination unit 102 determines whether or not the received electric field strength output in step SA-4 is equal to or greater than a predetermined threshold (step SA-5), and the slot ( For example, when a signal having a received electric field strength equal to or greater than a predetermined threshold is detected in the slot S1) (step SA-5: Yes), the frequency slot table 104 initialized in step SA-3 is set to be equal to or greater than the predetermined threshold. The frame number and slot number in which the received electric field strength appears are recorded for each monitor frequency (step SA-6). On the other hand, if a signal having a received electric field intensity equal to or greater than the predetermined threshold is not detected (step SA-5: No), the process proceeds to step SA-7.

  Then, the control unit 105 determines whether or not reception is completed in all slots (for example, all slots S1 to 24) in the reception unit 101 (step SA-7), and reception is performed in all slots. If it is determined that the process has not been completed (step SA-7: No), the slot number is updated (for example, updated from slot S1 to slot S2) (step SA-8), and the process returns to step SA-4. On the other hand, when it is determined that the reception is completed in all slots (for example, when the reception is completed in slot S24) (step SA-7: Yes), the process proceeds to step SA-9.

  And the control part 105 determines whether the monitoring time was complete | finished in the receiving part 101 (for example, whether the fixed time of 300 ms or more passed) (step SA-9), and the monitoring time was complete | finished If it is determined that it has not been performed (step SA-9: No), the frame number is updated (for example, updated from 1 frame to 2 frames) (step SA-10), and the process returns to step SA-4. On the other hand, if it is determined that the monitoring time has ended (step SA-9: Yes), the process proceeds to step SA-11 in FIG.

  As described above, the control unit 105 uses the reception unit 101 to detect radio wave interference, so that the reception frequency channel is a frequency channel within the use band of the DECT system (that is, the frequency band of 1893.5 MHz to 1906.1 MHz). Or interference in a frequency channel on a frequency band that is out of the use band (that is, on a frequency band that includes a harmonic component close to 1906.1 MHz in addition to the frequency band of 1893.5 MHz to 1906.1 MHz). Is set to a value including a frequency (for example, a frequency of 1898.450 MHz, 1900.250 MHz, or a frequency of 1906.650 MHz, 1907.150 MHz, 1907.750 MHz), and a reception operation is performed, At a constant time of at least 300 ms on the same frequency channel Performs the receiving operation in the frequency channel using all the slots of its own DECT system. Then, the interference type determination unit 102 records the frame number and the slot number in which the reception unit 102 detects a signal having a received electric field strength equal to or greater than a predetermined threshold in the frequency slot table 104 for each monitor frequency. For example, when the interference type determination unit 102 detects a signal in a certain slot (for example, the first slot), whether the signal can be detected in one of two slots adjacent to each other at a time position of about 5 ms from the slot. The slot number where the signal was detected is recorded.

  That is, the receiving unit 101 has a frequency band (that is, a frequency band of 1893.5 MHz to 1906.1 MHz) allocated to a digital cordless telephone that communicates with a base station using a plurality of time-division multiplexed time slots as frames, and , Receiving the frequency band assigned to the PHS (that is, the frequency band including the frequency band of 1893.5 MHz to 1906.1 MHz and the harmonic component close to 1906.1 MHz), and the received electric field strength of the received signal Is measured and output. The interference type determination unit 102 receives a received electric field of a signal continuously received by the reception unit 101 for a certain period of time at the time of activation or at any time (for example, before starting communication or when waiting for communication start). The intensity output is monitored, and the time width and frequency at which the received electric field intensity exceeding the predetermined threshold appears are measured.

  Subsequently, as shown in FIG. 8, the interference type discriminating means 102 determines the frame number and slot of the received signal having a received electric field strength equal to or higher than a predetermined threshold recorded in the frequency slot table 104 in step SA-6. The number check is started (step SA-11). That is, the interference type discrimination means 102 is based on the time width and frequency at which the received electric field strength exceeding the predetermined threshold appears and is recorded in the frequency slot table 104 measured in step SA-1 to step SA-10 in FIG. Then, it is determined whether or not there is interference due to a signal transmitted from a fixed station of PHS.

  First, the interference type determination unit 102 determines whether or not there is interference due to the PHS call channel (step SA-12).

  Specifically, in step SA-12, the interference type discrimination means 102 records the frequency of the signal having the received electric field strength equal to or greater than a predetermined threshold recorded in the frequency slot table 104 in step SA-6, and the time slot. The slot number (eg, S4, S16, etc.) corresponding to the frame number and the frame number (eg, 1 frame, 2 frames, etc.) corresponding to the frame are monitored, and when a certain time of at least 300 ms has passed, A signal is detected with a time width corresponding to a slot or two slots (for example, a time width corresponding to one slot corresponding to S4, or a time width corresponding to two slots corresponding to S4 and S5). Appears at a frequency of 5 ms period (for example, 5 ms period of S4 → S16 → S4), the PHS communication channel It determines that there is caused interference.

  Here, in step SA-12, the interference type discriminating means 102 corresponds to the frequency and the time slot of the signal having the received electric field strength equal to or greater than the predetermined threshold recorded in the frequency slot table 104 in step SA-6. Slot number (for example, S5, S6, etc.) and a frame number (for example, 1 frame, 2 frames, etc.) corresponding to the frame, and when a certain time of at least 300 ms has elapsed, A signal is detected with a time width of two slots (for example, one slot corresponding to S5 or two slots corresponding to S4 and S5), and then a signal having substantially the same received electric field strength is 10 ms. If it appears at a frequency of a period (for example, a period of 10 ms from S5 to S5), it may be caused by a DECT communication channel. It may determine that there is.

  Then, when it is determined in step SA-12 that there is no interference due to the PHS communication channel (step SA-12: No), the interference type determination unit 102 determines whether there is interference due to the PHS control channel. (Step SA-13).

  Specifically, in step SA-13, the interference type discrimination means 102 records the frequency of the signal having a received electric field strength equal to or greater than a predetermined threshold recorded in the frequency slot table 104 in step SA-6, and the time slot. The slot number (eg, S4, S16, etc.) corresponding to the frame number and the frame number (eg, 1 frame, 2 frames, etc.) corresponding to the frame are monitored, and when a certain time of at least 300 ms has passed, A signal is detected with a time width corresponding to a slot or two slots (for example, a time width corresponding to one slot corresponding to S4, or a time width corresponding to two slots corresponding to S4 and S5). Is a period of 120 ms or more (for example, a public PHS has a period of 120 ms, and a private PHS has a period of 125 ms to 300 ms. If the frequency appears only once (for example, only once when 240 ms elapses in 300 ms), the interference by the PHS control channel occurs. It is determined that there is.

  On the other hand, if it is determined in step SA-12 that there is interference due to the PHS call channel (step SA-12: Yes), the process proceeds to step SA-15.

  Then, when it is determined in step SA-13 that there is interference due to the PHS control channel (step SA-13: Yes), the interference type determination unit 102 further determines the control channel of the PHS received by the reception unit 101. The frequency band is a frequency band including a private PHS control channel (that is, a frequency band including frequencies of 1898.450 MHz and 1900.250 MHz) or a frequency band including a public PHS control channel (that is, 1906.650 MHz, The frequency band including one of the frequencies 1907.150 MHz and 1907.750 MHz), so that the interference by the control channel of the private PHS among the PHS control channels or the interference by the control channel of the public PHS Whether or not Flop SA-14).

  On the other hand, when it is determined in step SA-13 that there is no interference due to the PHS control channel (for example, in the case of interference due to the communication channel of DECT) (step SA-13: No), the process proceeds to step SA-17. As for the interference of the DECT communication channel, the same DECT method allows the use of various efficient interference avoidances because the radio wave bandwidth, modulation / demodulation method, and transmission speed are the same.

  In this way, the interference type determination unit 102 detects a signal having substantially the same electric field strength every time in a cycle of 10 ms based on the result recorded in the frequency slot table 104, and the middle of the 10 ms cycle in which the signal is detected. When a signal having the same electric field strength is not detected in the slot located at, it is determined that the signal is a DECT control signal. In addition, the interference type determination unit 102 does not detect a signal having the same electric field strength while 125 ms has not elapsed since the slot where the signal was first detected, and the time position where 125 ms or more has elapsed since the slot where the signal was first detected. If a signal having the same electric field strength is detected in the slot, and the frequency channel in which the signal is detected is within the use band of the DECT system, it is determined that the signal is a control signal for a private PHS. To do. Further, the interference type discrimination means 102 is a case where a signal having substantially the same electric field strength is detected each time in one of two adjacent slots every 5 ms interval, and the frequency channel in which the signal is detected is determined as DECT. If it is out of the system use band, it is determined that the control signal is a public PHS.

  Subsequently, in the following steps SA-14 to SA-16, the communication slot setting means 103 performs interference caused by a signal transmitted from the PHS fixed station by the interference type discrimination means 102 in steps SA-12 and SA-13. When it is determined that there is an error (step SA-12: Yes and step SA-13: Yes), the frequency band and slot timing used by the digital cordless telephone are set so as to avoid the interference. Here, the setting contents indicating the frequency band and slot timing used by the digital cordless telephone set by the communication slot setting means 103 are recorded in the frequency slot table 104.

  Specifically, the communication slot setting unit 103 is a case where it is determined in step SA-13 that the interference type determining unit 102 has interference due to the PHS control channel (step SA-13: Yes), and the receiving unit 101, when the frequency band of the control channel of the PHS received by the terminal 101 is a frequency band including the control channel of the private PHS (that is, the frequency band including the frequencies of 1898.450 MHz and 1900.250 MHz) (step SA-14: self-supporting) ), All the time slots in the frequency band of the digital cordless telephone corresponding to the frequency band of the control channel of the private PHS (that is, all the time slots S1 to S24 having the frequency of 1898.450 MHz and 1900.250 MHz) are disabled. Specifically, the communication In the case where the interference setting discriminating unit 102 determines that there is interference due to the PHS control channel in step SA-13 (step SA-13: Yes), the receiver setting unit 103 at this time When the frequency of the received signal is a frequency band including the frequency (1898.450 MHz, 1900.250 MHz frequency) used for the control signal of the self-supporting PHS, that is, F3 or F4 (step SA-14: self-supporting), the self-supporting PHS The frequency band and slot timing used by the digital cordless telephone are set so that all the time slots (S1 to S24) of the frequency bands F3 and F4 of the digital cordless telephone corresponding to the control signal frequency are disabled. That is, it is set to use all slots S1 to S24 of each frequency band (F1, F2, F5) excluding the frequency bands F3 and F4 (step SA-15). Thereafter, the process proceeds to Step SA-17.

  Here, in step SA-15, the communication slot setting unit 103 similarly determines that there is interference by the PHS call channel by the interference type determination unit 102 in step SA-12 (step SA-12: Yes). All time slots in the frequency band of the digital cordless telephone corresponding to the frequency band of the control channel of the private PHS (that is, all time slots S1 to S24 having the frequencies of 1898.450 MHz and 1900.250 MHz) are disabled. In addition, the frequency band and slot timing used by the digital cordless telephone (that is, all slots S1 to S24 of frequencies within the frequency band of 1893.5 MHz to 1906.1 MHz excluding the frequencies of 1898.450 MHz and 1900.250 MHz) Set to. Thereafter, the process proceeds to Step SA-17.

  Then, the communication slot setting unit 103 is received when the interference type determining unit 102 determines that there is interference due to the PHS control channel in step SA-13 (step SA-13: Yes). When the frequency of the received signal is the frequency band F8 including the frequency (for example, 1906.65 MHz) used for the control signal of the public PHS base station (step SA-14: public), the frequency band of the control channel of the public PHS The slot number (eg, S4 and S5) in which the signal appears in all frequency bands used by the corresponding digital cordless telephone, and the slot number 2.5 ms, 5 ms, or 7.5 ms away from the slot number (For example, S10 and S11 in the + 6th slot, S16 and S1 in the + 12th slot Or the frequency band used by the digital cordless telephone and the slot timing (for example, a frequency within a frequency band of 1893.5 MHz to 1906.1 MHz, so that the time slot of the + 18th slot S22 and S23) is disabled. Slots S1 to S3, S6 to S9, S12 to S15, S18 to S21, S24, etc.) are set (step SA-16). Thereafter, the process proceeds to Step SA-17.

  As described above, the communication slot setting means 103, when a self-supporting PHS control signal is detected in a frequency channel within the use band of the DECT system, rejects a frequency channel in which the control signal is detected among a plurality of frequency channels. Recorded in the frequency slot table 104 for use. Further, when a public PHS control signal is detected in a frequency channel outside the use band of the DECT system, the communication slot setting unit 103 disables the slot in which the control signal is detected among the slots of the DECT system. As described above, it is recorded in the frequency slot table 104.

  Subsequently, the control unit 105 determines whether or not the above-described processing has been completed for all frequencies in the receiving unit 101 (step SA-17), and if it is determined that the processing has not been completed for all frequencies (step SA17). SA-17: No), returning to FIG. 7, the monitor frequency is updated (step SA-18), and the process returns to step SA-2. On the other hand, when it is determined that the processing has been completed for all frequencies (step SA-19: Yes), the processing proceeds to step SA-19 in FIG.

  When the interference type determination unit 102 determines that there is interference due to the PHS control channel or the communication channel (step SA-12: Yes, or step SA-13: Yes), the control unit 105 performs step SA-. By outputting the frequency band and slot timing (that is, the setting contents recorded in the frequency slot table 104) used by the digital cordless telephone set by the communication slot setting means 103 in steps 14 to SA-16 to the transmission unit 106 Then, control is performed so as to notify the wireless communication device of another digital cordless telephone (step SA-19).

  Through the processing described above, the transmitting unit 106 can transmit communication data using the frequency band and slot timing assigned to the digital cordless telephone by the communication slot setting unit 103.

Above, description of an example of the process in the radio | wireless communication apparatus in embodiment is finished.
[3. Summary of this embodiment]
As described above, the configuration and processing of the present embodiment have been described in detail. However, according to the present embodiment, the wireless communication device 100 is activated or at any time (for example, before starting communication or waiting for communication start). In a plurality of frequency channels and time slots used for data transmission, the interference type discrimination means 102 that performs radio wave interference detection processing accurately determines the control signal of the private PHS or public PHS. By not using the frequency channel and time slot corresponding to the control signal, collision with the control signal of the PHS system can be avoided, and coexistence with the PHS system can be achieved. For example, when the present wireless communication apparatus is implemented with a DECT digital cordless telephone, even if a PHS digital cordless telephone is present in the vicinity, the DECT telephone causes radio wave interference to the outgoing PHS control signal. I can not.

  Also, according to the present embodiment, the radio communication apparatus 100 uses the interference type determination unit 102 to set the interference source type to a private PHS control channel, a public PHS control channel, a PHS communication channel, and a DECT communication channel. Further, the communication slot setting means 103 and the frequency slot table 104 can be used to restrict the use of frequencies and slots according to the interference source type, and the communication channels can be segregated according to frequency and time timing. Therefore, even if the use frequency band is shared with the PHS, a radio communication apparatus that does not cause radio wave interference with the PHS can be realized.

  The wireless communication device and wireless communication method for a digital cordless telephone according to the present invention are useful in various industrial fields such as the wireless communication field, and are particularly suitable for avoiding interference between the PHS system and the DECT system.

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 101 Receiving part 102 Interference classification discrimination means 103 Communication slot setting means 104 Frequency slot table 105 Control part 106 Transmission part

Claims (7)

A wireless communication device that receives a signal in which a plurality of time slots that are time-division multiplexed in a frequency band that overlaps a frequency band of PHS is a frame,
A discriminating means for discriminating whether the interference is caused by the control channel of the private PHS fixed station from the received signal;
Control means for disabling all time slots in a frequency band overlapping with a frequency band used by the control channel of the private PHS when there is interference by the control channel of the private PHS fixed station in the determination means; ,
A wireless communication apparatus comprising: The discrimination means includes
Monitor a signal in which a received electric field strength of a predetermined threshold or higher appears in a frequency band overlapping with a frequency band used by the control channel of the private PHS fixed station, and set a slot number corresponding to the time slot in which the signal is received. The signal is detected with a time width of one slot or two slots in the monitoring period of at least 300 ms and then a signal having substantially the same received electric field strength appears in a period of 120 ms or more, or If it appears at least once, determining that there is interference from the control channel of the private PHS fixed station;
The wireless communication apparatus according to claim 1. When there is interference due to the control channel of the private PHS fixed station, the wireless communication apparatus transmits information indicating that all time slots in the frequency band used by the control channel of the private PHS fixed station are unusable. To do,
The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device. The wireless communication device transmits a frequency band and time slot information usable by the wireless communication device;
The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device. The wireless communication device is a cordless phone or a cordless phone;
The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device. The wireless method used by the wireless communication device is a wireless method compliant with the DECT method using a frequency band overlapping with the PHS frequency band,
The wireless communication apparatus according to any one of claims 1 to 5, wherein: Receiving a signal having a plurality of time slots that are time-division multiplexed in a frequency band overlapping with the PHS frequency band as a frame;
From the received signal, determine whether the interference is due to the control channel of the private PHS fixed station,
When there is interference due to the control channel of the private PHS fixed station, disabling all time slots in the frequency band overlapping with the frequency band used by the control channel of the private PHS,
A wireless communication method characterized by the above.

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