JP4316749B2 - Wireless synchronization method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless synchronization method, and more particularly to a wireless synchronization method that realizes reduction of radio wave interference by determining transmission timings of control signals or communication signals when a plurality of wireless communication systems are arranged.
[0002]
[Prior art]
In general, in a time division multiple access (TDMA) mobile communication system, call control is performed using a predetermined control signal for call control between a radio base station and a radio slave unit. Frequency is assigned to control the call. A standard for this control method has been established by the Association of Radio Industries and Businesses (ARIB).
[0003]
Since the frequency for control by this control signal is common in the mobile communication system of the same system, there is an obligation to avoid radio wave interference. For this reason, it is necessary to prevent the transmission positions of the control signals from overlapping at the control frequency broadcast from the radio base stations of the own system and of other systems.
[0004]
As a method of avoiding such interference, generally, when the power of the radio base station is turned on, the position of the control signal transmitted by the surrounding radio base station so that each radio base station broadcasts control information. The transmission position is determined so as not to overlap with each other, and control signals notified by each radio base station are classified.
[0005]
[Problems to be solved by the invention]
In the conventional method, when segregating control signals under the management of the own system, for example, synchronization of all radio bases is established to eliminate overlapping of radio sections and control of radio base stations is started when operation is started. By determining the timing of the signal transmission position, it was possible to avoid interference due to the control signal. However, an asynchronous system such as a case where a mobile radio system using the same method other than its own system (for example, a digital cordless telephone system using the same frequency as a control signal and having a different operation form) is operated in the vicinity is installed later. (For example, when a digital cordless telephone base unit for home use or a public-independent repeater is installed later in a premises where a digital cordless telephone system for offices is operated) If the wireless base station cannot send out the control signal due to mutual interference of the control signal with, or if it tries to detect the section without interference again using the interference avoidance algorithm, there is no free section, For avoiding interference such as being unable to operate as a base station and building a wireless area There is a field. The limit for avoiding interference is the same for the frequency for calls. This is because, for example, the phase of the radio transmission frame starts to shift during long-term operation, and another radio base station is installed in the vicinity of the radio base station. This is because the mobile station cannot make or receive calls.
[0006]
In view of the above points, the present invention stores the radio wave level, transmission timing position, and phase information of a control signal or communication signal that can be an interference wave caused by the proximity of a plurality of mobile radio systems for each radio base station. Then, it aims at reducing the frequency of interference by controlling the transmission position of a control signal or a communication signal.
[0007]
[Means for Solving the Problems]
According to the first solution of the present invention,
A wireless synchronization method in a wireless communication system comprising a wireless base station or a wireless master or repeater and a wireless slave, wherein the wireless base station or the wireless master or repeater performs call connection control on the wireless slave,
When a plurality of wireless communication systems that perform call connection control are installed close to each other, a control signal or a communication signal transmitted from each other wireless communication system is monitored to detect a radio wave interference section,
Provided is a radio synchronization method in which a transmission position of a control signal or a communication signal transmitted from its own radio communication system is controlled to a position within a predetermined no-interference section that is separated in time from a detected interference section.
[0008]
According to the second solution of the present invention,
A wireless synchronization method in a wireless communication system comprising a wireless base station or a wireless master or repeater and a wireless slave, wherein the wireless base station or the wireless master or repeater performs call connection control on the wireless slave,
Monitor control signals or communication signals transmitted from other surrounding wireless base stations or wireless master units or repeaters,
Detect non-interference sections without radio wave interference from other radio base stations or radio base stations or repeaters according to the monitoring results,
Assign a predetermined time in the no-interference section to the transmission position of the control signal or communication signal of the own radio base station or radio base station or repeater,
Shift your own sending position to correct the difference between the assigned sending position and the previous sending position,
Provided is a wireless synchronization method for transmitting a control signal or a communication signal at the transmission position when the assigned transmission position can be transmitted periodically.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 shows a configuration diagram of an adjacent asynchronous wireless communication system.
FIG. 1 shows, as an example, a configuration example in which an office digital cordless telephone system, a home digital cordless telephone master unit, and a repeater device are arranged as a plurality of wireless communication systems in a premises such as an office or a factory. . The office digital cordless telephone system includes a private branch exchange (101), radio base stations (102 to 104) connected thereto, and an office digital cordless telephone (111). In addition, home master units (105 to 107) are connected as extension telephones of the private branch exchange (101). The home master unit (105 to 107) has a pair of slave units (112 to 113). The drawing further shows that radio wave repeaters (repeaters) (108 to 110) for public PHS are installed in the same premises area (115). The wireless communication system that is the subject of the present invention may include other private branch exchanges and wireless base stations, base units, repeaters, and the like connected thereto.
[0010]
Since the wireless base stations (102 to 104) for the digital cordless telephone system for offices are all arranged so that the inside of the campus area (115) is a service area, the mobile station (111) for this system is located in the campus area (115). ) Communication is possible even if it moves inside. The wireless base station (102 to 104) of the digital cordless telephone system for offices, the master unit (105 to 107) and the repeater (108 to 110) of the home digital cordless phone are, for example, wirelessly connected to each mobile station or slave unit. When the communication method is the same, the same control frequency is used in a time division manner. Each of the wireless base stations (102 to 104), the parent device (105 to 107), etc. determines the timing for sending a control signal for performing call control of wireless communication based on its own timing. Normally, it has a function to avoid interference so that the timing does not interfere with other systems, detects the transmission timing of control signals of surrounding devices, and controls the control signal of its own system at a timing that has no effect In order to determine the timing of sending out, the effect is small if the number is small.
[0011]
However, when the wireless base stations (102 to 104) and the master units (105 to 107) of different systems are arranged close to each other as in the campus area (115), each wireless section is asynchronous. When the number of arrangements increases, the time until the transmission timing of each control signal is determined and the transmission position of the control signal may overlap. Therefore, a method for shortening the processing time and a specific procedure capable of reducing radio wave interference of different systems are shown below.
[0012]
FIG. 2 shows a conceptual diagram of a TDMA-TDD frame in a radio section.
FIG. 2A is a conceptual diagram of a TDMA-TDD frame in a radio section formed by a radio base station for a business digital cordless telephone system. As an example, this processing is a slot configuration of a radio section of the second generation cordless telephone system standard standardized by ARIB. One slot, which is the minimum unit, is 625 μs, and eight slots are configured as one frame (201). The
[0013]
As shown in FIG. 2 (B), each radio base station uses a high-precision timing clock, and its stability is defined by the above-mentioned standard, but the accuracy for each radio base station. Depending on the hardware used, deviation may occur even within the standard range. In the following, when there is a TDMA-TDD frame (202) of the radio base station A and a TDMA-TDD frame (203) of the radio base station B using the conceptual diagram of FIG. A description will be given of how the timing shifts with the passage of time when the slots coincide on the time axis. When the slots 1 of the TDMA-TDD frames of the radio base station A and the radio base station B match each other, the phase shift (204) is small in a short period, but the phase shifts 205 and 206 occur in a long period and a long period. Such a deviation will occur. For this reason, when the radio base stations A and B that initially used a slot with no interference between the slots are operated for a long time, an interference in which a deviation (204) unit for each frame is accumulated occurs. For this reason, there is little effect in a system having a means for matching the heads of TDMA frames of all radio base stations under the control of a private branch exchange such as a digital cordless telephone system for offices. In an environment where the systems are installed close to each other, it becomes difficult to reduce the influence. Therefore, a specific method for avoiding the influence of these radio waves will be described below.
[0014]
FIG. 3 is an explanatory diagram showing a method for reducing the influence of radio wave interference.
FIG. 3 shows an environment in which asynchronous mobile radio systems are close to each other as shown in FIG. 1, in which the radio base station A has a period of timings (301) and (302), and the home base station A has timings (303) and (304 ), The parent master B transmits control signals at the timings (305) and (306), and the repeater A transmits the control signals at the timings (307) and (308). It shows that the signals are operating without interference. In addition, when the radio base station N is about to start a new operation and searches for the status of surrounding radio waves, a section (309, 311) that is affected by interference and a section (310) that is not affected by interference. Is detected. Here, the radio base station N stores the first position (313) and the last position (314) of the section (310) without interference in the internal memory unit. Furthermore, when there is no influence of interference even after the period of time during which the non-interference period occurs is monitored for a certain period of time, for example, the position of 1/2 of the non-interference section is the transmission position (312) of the control signal of the radio base station N And decide. A relative relationship (315) between the initial position of the non-interference section and the transmission position of the base station is obtained and stored in the memory unit as the above position. By setting the transmission position to a half of the no-interference section, as shown in FIG. 2, the time until the influence of interference occurs due to the shift of the position of each control signal due to long-term operation is extended. can do. However, there are cases in which it is not possible to fundamentally take control measures for interference of control signals and interference avoidance processing due to phase shifts that occur during long-term operation. Here, as an example, the case where the transmission position is set to a half of the no-interference section has been described. However, the transmission position is not limited to 1/2, but 1/3, 2/3, 1/4, 3/4, and the like. It can be installed at an appropriate position. Half of the transmission slot is acceptable.
[0015]
FIG. 4 is an explanatory diagram for the phase shift calibration of the control signal. FIG. 4 is a means for calibrating the phase shift of the control signal generated during long-term operation.
Here, during the long-term operation, when monitoring the transmission timing of the control signal of the own radio base station and the surrounding radio wave condition, the deviation (402) in the correlation between the timing stored in the initial operation (315) is constant. If it occurs above the value, the transmission position of the control signal of the own radio base station is shifted (403) in the direction opposite to the direction of the phase shift. When this means is used, the transmission timing at the time of initial operation can always be held as described above, and interference avoidance corresponding to the wireless base station of the surrounding asynchronous system can be performed. In addition, as an opportunity to calibrate the phase shift of the control signal during operation, at power-on, at the end of call connection processing with the mobile station, at the time of rising from the sleeping state or at every predetermined number of rising times, or By performing the operation every predetermined timing and every predetermined time during the operation, each wireless base station can independently reduce the influence of the interference of the control signal.
[0016]
FIG. 5 shows a hardware configuration diagram of the radio base station. Here, a radio base station will be described as an example, but the same configuration can be adopted for a base unit, a repeater, and the like.
The radio base station performs antenna modulation and demodulation on an antenna (601) for transmitting and receiving radio waves, a switching unit (602) for two antennas, a transmission unit (603), a reception unit (605), a synthesizer unit (604) for generating a frequency. A modem unit (606), a TDMA-TDD processing unit (607), a line interface unit (608), a memory unit (513), a CPU (610), and a power supply unit (611). Since the present invention can be realized by storing each data in the memory unit (513) installed in each radio base station, the processing of the present invention can be installed in each radio base station, base unit, and repeater. Therefore, each radio base station itself can reduce the frequency of radio wave interference.
[0017]
FIG. 6 shows an example of a configuration diagram of data stored in the memory unit. In this example, the memory unit (513) stores the base station ID number, electric field strength level, end position, start position, cycle, and the like for the types of radio base station, base unit, repeater, and the like. Further, the memory unit (513) stores the local station transmission position. The radio base station holds the phase information of other base stations in an array in the flow process for reducing radio wave interference in FIG. By holding the ID number and field strength level of other radio base stations, the end position and start position of the transmitted radio wave, calculating and storing the phase period of the interference wave by each base station, It is possible to update the transmission timing position deviation correction of the own radio base station and the calculation of the interference interval or non-interference interval in real time.
[0018]
FIG. 7 shows a flowchart of processing for reducing the influence of radio wave interference. After the radio base station is turned on, first, the control signals of the surrounding radio base stations and the home base unit for home use are continuously processed in time (502) and stored in the memory unit (513). To do. Thereafter, it is determined whether or not there is a section without radio wave interference from another radio base station or the like based on the detection result by this reception processing (503), and if there is, a series of procedures (516) indicated by a broken line is performed. Do.
[0019]
As a series of procedures (516) relating to the present invention, first, the phase (position and period) of the timing without interference is calculated from the data stored in the memory unit (513) (509), and half the time is automatically calculated. A control signal transmission position of the wireless base station is temporarily allocated (510). It should be noted that the timing is not limited to 1/2, and may be set to appropriate timing such as 1/3, 1/4, and 3/4. At this time, whether or not there is a deviation from the previous transmission position of the own radio base station is compared (511), and if there is a deviation, the difference of the deviation is corrected (512). The method of correcting this deviation is as described above. Thereafter, it is detected (505) whether or not the assigned transmission position can be transmitted periodically. If transmission is possible, the control channel is transmitted at this position, and the phase (position and cycle of the start point and end point) at the time of transmission is stored in the memory unit (513). When storing, if there is phase information at the time of the previous transmission in the memory unit (513), the data is updated (514), the latest information is always held, and the operation operation (508) is performed. As a result, even if a phase shift occurs during operation, it takes a long time for the control signal transmission position to be selected next to receive radio wave interference again. It is possible to reduce the frequency of interference.
[0020]
Further, during the operation operation, a non-interference section is detected every appropriate time or every appropriate state as described above, and if there is a timing deviation (515), the process proceeds to step 502 and a series of procedures is executed. . In addition, since the phase information of the interference wave is stored in the memory unit (516) in advance, processing for shifting the phase in the reverse direction can be easily performed by comparison with the past transmission position during operation. In addition, it is possible to shorten the time for selecting the delivery position.
[0021]
On the other hand, when interference is detected in step 505 and transmission is impossible, the re-search process from step 502 is repeated N times (504). If an appropriate transmission position is not detected after N times, it is determined that the logical control channel cannot be transmitted (507). Also, after sending out the control channel in step 506, the operation moves to operation (508). Further, it is determined whether or not the transmission timing of the control channel is the phase detection timing of interference (515).
[0022]
In the above description, control signal interference has been mainly described. However, the present invention can be applied not only to control signals but also to communication signals that transmit various types of information and data.
[0023]
【The invention's effect】
According to the present invention, as described above, the radio signal level, transmission timing position, and phase information of a control signal or communication signal that can be an interference wave caused by the proximity of a plurality of mobile radio systems are stored for each radio base station. In addition, the frequency of interference can be reduced by controlling the transmission position of the control signal or the communication signal.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an adjacent asynchronous mobile communication system.
FIG. 2 is a conceptual diagram of a TDMA-TDD frame in a wireless section.
FIG. 3 is an explanatory diagram for reducing the influence of radio wave interference.
FIG. 4 is an explanatory diagram regarding phase shift calibration of a control signal.
FIG. 5 is a hardware configuration diagram of a radio base station.
FIG. 6 is a configuration diagram of data stored in a memory unit.
FIG. 7 is a flowchart of processing for reducing the influence of radio wave interference.
[Explanation of symbols]
(101) Private branch exchanges for digital cordless telephone systems for offices (102) to (104) Radio base stations for digital cordless telephone systems for offices (105) to (107) Master units for digital cordless telephones for home use (108) to (110) Radio wave repeater (111) Mobile station for digital cordless telephone system for offices (112) to (114) Slave unit for digital cordless telephone for home use (115) Local area (201) TDMA-TDD frame configuration (202) Wireless base station A TDMA-TDD frame configuration of A (203) TDMA-TDD frame configuration of radio base station B (204), (205),
(206) Difference between radio base station A and radio base station B in units of frames (301) to (302) Transmission slot positions of control signals for radio base station A (303) to (304) Control signal for home base unit A Transmission slot positions (305) to (306) Transmission slot positions (307) to (308) of control signal for home base station B Transmission slot positions (309) and (311) for control signal of repeater A Interference section (310) Section where there is no interference between surrounding control signals (312) Transmission slot position of control signal of wireless base station N (313) End point of interference section (314) Start point of interference section (315) Interference Correlation between wave and transmission position of radio base station N (401) Control signal transmission slot position after N seconds of radio base station N (402) Phase of transmission slot between initial operation and N seconds Misalignment (403) Transmission slot phase shift (601) Radio base station antenna (602) Radio base station antenna switching unit (603) Radio base station transmission unit (604) Radio base station synthesizer unit (605) Radio base Station reception unit (606) Radio base station modem unit (607) Radio base station TDMA-TDD processing unit (608) Radio base station line interface unit (609) Radio base station memory unit (610) Radio base station CPU
(611) Power supply unit of radio base station

Claims (2)

A wireless synchronization method in a wireless communication system comprising a wireless base station or a wireless master or repeater and a wireless slave, wherein the wireless base station or the wireless master or repeater performs call connection control on the wireless slave,
It monitors the control signal or communication signal is transmitted from the other surrounding radio base station, or other radio cell station or other repeaters, the monitoring result by from another wireless base station or other radio cell station or other repeaters Detect non-interference section without radio wave interference,
A transmission start position of a control signal or communication signal transmitted by the wireless base station, wireless base station or repeater is determined within the detected no-interference section, and a control signal or communication signal is transmitted. Find and store the phase difference between the initial position and the determined delivery start position,
In the state where the control signal or communication signal is periodically sent based on the determined sending start position, the sending position of the sending control signal or communication signal and the surrounding radio wave state are monitored,
Stored when the difference between the phase difference between the transmission position of the transmitted control signal or communication signal and the first position of the no-interference section detected again based on the monitoring result and the stored phase difference is equal to or greater than a predetermined value. Correct the transmission position of the control signal or communication signal so that the transmission position is the same as the phase difference, and send it out.
And a wireless synchronization method. The transmission start position of the control signal or communication signal transmitted by the wireless base station or wireless base station or repeater is determined and transmitted to a position that is 1/2 or substantially 1/2 of the detected no-interference section.
The wireless synchronization method according to claim 1 .

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