JP5352631B2 - Wireless communication system and leaky coaxial cable used in this system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent instability of communications when a mobile station switches access points to connect to during roaming. <P>SOLUTION: There is provided a wireless communication system comprising: a first access point used as an antenna by being connected to a first leaky coaxial cable; and a second access point arranged in the vicinity of a terminal end of the first leaky coaxial cable and used as an antenna by being connected to a second leaky coaxial cable. A reception level of leaky electronic waves received by the mobile station from the first leaky coaxial cable is decreased to a level at which the mobile station starts a roaming process, over a predetermined length extending from the terminal end of the first leaky coaxial cable to a base end. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  Embodiments described herein relate generally to a wireless communication system using a leaky coaxial cable.

  There is a wireless communication system in which a leaky coaxial cable is connected to an access point which is a base station as an antenna, and the access point performs wireless communication with a mobile station via this antenna. The leaky coaxial cable used in this system can secure a communication area of a very long distance. However, since there is a transmission loss in the radio wave propagating through the cable, it is natural that the distance of the communication area that can be realized by one access point is finite.

  In a general wireless LAN (Local Area Network) system, roaming is known as a technique for expanding a communication area. Roaming is a technology in which a wireless LAN client moving within an area where a plurality of wireless LAN access points are arranged switches access points to be connected in accordance with the movement.

  Even in a wireless communication system using a leaky coaxial cable, the distance of a communication area can be increased by applying a roaming technique. However, the leaky coaxial cable has a sharp change in the amount of radio wave attenuation in the vicinity of the terminal portion as compared with a general monopole antenna. For this reason, there is a problem that communication becomes unstable when switching the access point to be connected, and real-time communication becomes impossible.

JP 2007-116251 A

  A problem to be solved by the present invention is to provide a leaky coaxial cable that can prevent instability of communication when a mobile station switches a connection destination access point by roaming, and can stably maintain the real-time property of communication. The present invention intends to provide a used wireless communication system.

  In one embodiment, a wireless communication system includes a first access point that is connected to a first leaky coaxial cable and serves as an antenna, and is disposed in the vicinity of a terminal portion of the first leaky coaxial cable. And a second access point that serves as an antenna. The reception level of the leaked radio wave received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the first leaky coaxial cable is a level at which the mobile station starts roaming processing. To lower.

The conceptual diagram of the radio | wireless communications system in 1st Embodiment. The figure which shows the relationship between the reception level and movement distance of a client terminal in the radio | wireless communications system in 1st Embodiment. The schematic diagram which shows the 1st specific example of the leaky coaxial cable used with the radio | wireless communications system of 1st Embodiment. The schematic diagram which shows the 2nd specific example of the leaky coaxial cable used with the radio | wireless communications system of 1st Embodiment. The schematic diagram which shows the 3rd specific example of the leaky coaxial cable used with the radio | wireless communications system of 1st Embodiment. The schematic diagram which shows the 4th specific example of the leaky coaxial cable used with the radio | wireless communications system of 1st Embodiment. The conceptual diagram of the radio | wireless communications system in 2nd Embodiment. The conceptual diagram of the radio | wireless communications system in 3rd Embodiment.

Hereinafter, some embodiments will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a conceptual diagram of a wireless communication system according to the first embodiment. This system connects a first leaky coaxial cable 1 having a total length of about 200 meters and a first access point 2 that is connected to a first leaky coaxial cable 3 having a total length of about 200 meters. And a second access point 4 serving as an antenna. The second access point 4 is disposed in the vicinity of the terminal end of the first leaky coaxial cable 1. With this arrangement, the communication area on the proximal end side of the second leaky coaxial cable 3 overlaps with the communication area on the terminal end side of the first leaky coaxial cable 1. As a result, an elongated communication area of about 400 meters is secured from the first leaky coaxial cable 1 to the second leaky coaxial cable 3.

  Although not shown, the access points 2 and 4 are connected by a wired LAN. The control server of the client terminal 5 is connected to this wired LAN. The client terminal 5 moves along the first and second leaky coaxial cables 1 and 3 in the direction of the arrow X or −X in the figure. Then, the client terminal 5 performs radio communication with the first or second access point 2 or 4 by using the radio wave leaking from the first and second leaky coaxial cables 1 and 3. Through this wireless communication, the client terminal 5 receives a control signal from the control server. That is, the client terminal 5 becomes a mobile station for the first or second access point 2 or 4.

  Even when the client terminal 5 moves from the communication area of the first leaky coaxial cable 1 to the communication area of the second leaky coaxial cable 4 or in the opposite direction, the connection with the control server is maintained. The system uses roaming technology. Therefore, the ESSID (Extended Service Set Identifier) set in each of the access points 2 and 4 is the same. However, in order to prevent radio wave interference, the first access point 2 and the second access point 4 use different frequencies. In the present embodiment, the first access point 2 uses the i channel (ch.i), and the second access point 4 uses the j channel (ch.j).

  Among the roaming technologies, a technology called so-called background scanning is known in which the access point is switched smoothly by searching for the next access point to be connected during communication. . In addition, there is also known a method in which when a high throughput is required, the roaming threshold is changed, and when a high throughput cannot be obtained, an access point is switched intentionally. Therefore, as in this system, by installing a plurality of access points 2 and 4 having leaky coaxial cables 1 and 3 and performing roaming processing with the above-described background scan and optimization of the roaming threshold, it is high. It is thought that a long communication area can be secured with a high throughput.

  However, the leaky coaxial cables 1 and 3 have a large amount of radio wave attenuation near the end due to their unique radiation shape and directivity. For this reason, when performing roaming by background scanning, communication becomes unstable when the connection destination of the client terminal 5 is switched from the first access point 2 to the second access point 4, and real-time communication is possible. There is a risk that it will not be possible.

  In order to solve such a problem, in this system, the leakage that the client terminal 5 receives from the first leaky coaxial cable 1 over a predetermined length from the terminal end to the base end of the first leaky coaxial cable 1 The radio wave reception level is lowered to a level at which the client terminal 5 starts roaming processing.

  A solution to such a problem will be described with reference to FIG. The roaming process of this system starts a background scan when the current reception level is 30 or less in the client terminal 5 moving at a speed of 2 meters per second. As a result of the scan for 5 seconds, the reception level is 40 or more. Assume that a switch is made when an access point is found.

  In FIG. 2, the horizontal axis indicates the moving distance [meter] of the client terminal 5 from the first access point 2, and the vertical axis indicates the leakage radio wave reception level of the client terminal 5. In FIG. 2, the solid line P indicates the reception level with respect to the travel distance of leaked radio waves from the first leaky coaxial cable 1, and the alternate long and short dash line Q indicates the receive level with respect to the travel distance of leaked radio waves from the second leaky coaxial cable 3. Indicates. A broken line R indicates the reception level of the conventional specification with respect to the travel distance of the leaked radio wave from the first leaky coaxial cable 1.

First, the case where the client terminal 5 moves in the X direction along the first and second leaky coaxial cables 1 and 3 will be described.
As shown by a broken line R in FIG. 2, in the conventional specification, the leaked radio wave from the first leaky coaxial cable 1 is transmitted from the base end portion of the leaky coaxial cable 1 connected to the first access point 2. The reception level exceeds 30 up to around 200 meters, which is the end of 1. However, if it exceeds 200 meters, the reception level will attenuate rapidly.

  When the reception level becomes 30 or less at the distance x5 (> 200 meters), the client terminal 5 moving in the X direction starts roaming processing. This roaming process requires a scan time of about 5 seconds. The moving speed of the client terminal 5 is 2 [m / sec]. Therefore, the moving distance Δt of the client terminal 5 during the roaming process is about 10 meters.

  When the client terminal 5 moves about 10 meters in the X direction from the point of the distance x5 and reaches the point of the distance x6 (> x5), the roaming process ends. At this time, the leaked radio wave reception level from the second leaky coaxial cable 3 exceeds 40. Therefore, the client terminal 5 switches the wireless LAN connection destination from the first access point 2 to the second access point 4. However, the client terminal 5 cannot receive the leaked radio wave from the first leaky coaxial cable 1 during the roaming processing execution period t5 to t6. For this reason, communication becomes unstable, and real-time communication becomes impossible.

  On the other hand, as shown by the solid line P in FIG. 2, in the case of the specification of this system, the client terminal 5 moving in the X direction has a distance x3 (150 < At the point of x3 <190), the leaked radio wave reception level of the first leaky coaxial cable 1 is 30 or less. As a result, the client terminal 5 starts roaming processing.

  When the client terminal 5 moves about 10 meters in the X direction from the point of the distance x3 and reaches the point of the distance x4 (> x3), the roaming process ends. At this time, the leaked radio wave reception level from the second leaky coaxial cable 3 exceeds 40. Therefore, the client terminal 5 switches the wireless LAN connection destination from the first access point 2 to the second access point 4. And in the roaming process area t3-t4 at this time, since the leakage electric wave reception level of the 1st leaky coaxial cable 1 is also around 25, communication is stable. Therefore, the client terminal 5 moving in the X direction switches the connection destination from the first client terminal 2 to the second client terminal 5 while maintaining real-time communication.

Next, a case where the client terminal 5 moves in the −X direction will be described.
As indicated by a one-dot chain line Q in FIG. 2, the leakage level of the leaked radio wave from the second leaky coaxial cable 1 gradually changes when the base end connected to the second access point 4 is removed. When the reception level becomes 30 or less at the distance x2 (<190 meters), the client terminal 5 moving in the −X direction starts roaming processing. Then, when the client terminal 5 moves about 10 meters in the −X direction from the point of the distance x2 and reaches the point of the distance x1 (<x2), the roaming process ends. At this time, the leaked radio wave reception level from the first leaky coaxial cable 1 exceeds 40. Accordingly, the client terminal 5 switches the wireless LAN connection destination from the second access point 4 to the first access point 2. And in the roaming process area t2-t1 at this time, since the leaked radio wave reception level of the second leaky coaxial cable 3 is 20 or more, the communication is stable. Therefore, the client terminal 5 moving in the −X direction switches the connection destination from the second client terminal 5 to the first client terminal 2 while maintaining real-time communication.

  Now, in the present system, the first leaky coaxial cable 1 is configured so that the client terminal 5 has the first leaky coaxial cable larger than the other parts over a predetermined length from the terminal end to the base end. 1 is reduced to a level at which the client terminal 5 starts roaming processing. That is, it can be said that the first leaky coaxial cable 1 is a combination of two or more leaky coaxial cables having different coupling losses.

  A specific example of such a leaky coaxial cable will be described with reference to FIGS. 3 to 6, each of the leaky coaxial cables 11, 12, 13, and 14 is configured to include an inner conductor, an insulator, an outer conductor, and a sheath, and is periodically formed on the outer conductor. The point that the slot 6 is provided is the same as in the prior art. In addition, the leaky coaxial cables 11, 12, 13, and 14 are connected to the power supply line (approach cable) of the access point 2 at the base end portion, and the terminator is connected to the terminal end. It is the same.

  In each leaky coaxial cable 11, 12, 13, 14 shown in FIGS. 3 to 6, the section A is a section where the coupling loss is small and the radiation intensity of the leaked radio wave is strong. On the other hand, the section B is a section where the coupling loss is large and the radiation intensity of the leaked radio wave is strong. It is essential that the length of the section B is longer than the distance traveled while the client terminal 5 performs the roaming process. Moreover, it is preferable to make it a value as close as possible to this moving distance.

  The leaky coaxial cable 11 shown in FIG. 3 apparently has a coupling loss in the section B by shifting the distance d2 between the slots 6 formed in the section B wider than the distance d1 between the slots 6 formed in the section A. Is made larger than section A. In section B, the reception level of leaked radio waves received by the client terminal 5 from the leaky coaxial cable 10 is reduced to a level at which the client terminal 5 starts roaming processing.

  In the leaky coaxial cable 12 shown in FIG. 4, the size of each slot 6 b formed in the section B is reduced with respect to each slot 6 a formed in the section A, so that the coupling loss of the section B is apparently reduced in the section A. Larger than. In section B, the reception level of leaked radio waves received by the client terminal 5 from the leaky coaxial cable 10 is reduced to a level at which the client terminal 5 starts roaming processing.

  In the leaky coaxial cable 12, the interval d 1 between the slots 6 a formed in the section A is equal to the interval d 2 between the slots 6 b formed in the section B, but the interval between the slots 6 b as in the leaky coaxial cable 11. Also, the coupling loss in the section B may be made larger than that in the section A by shifting it widely.

  In the leaky coaxial cable 13 shown in FIG. 5, the interval and size of the slots 6 formed in the sections A and B are the same as the existing one. The leaky coaxial cable 13 apparently makes the coupling loss in the section B larger than that in the section A by covering the periphery of the sheath, which is the jacket of the cable in the section B, with the radio wave shielding sheet 7. In section B, the reception level of leaked radio waves received by the client terminal 5 from the leaky coaxial cable 10 is reduced to a level at which the client terminal 5 starts roaming processing.

  Such a leaky coaxial cable 13 can adjust the amount of radio wave complementarity by changing the thickness of the radio wave shielding sheet 7, for example, so that more stable roaming can be achieved.

  The radio wave shielding sheet 7 is necessary when the client terminal 5 moves in the X direction in FIG. 1, but is not necessary when the client terminal 5 moves in the -X direction. Therefore, the moving direction of the client terminal 5 is detected. When moving in the X direction, the area around the section B of the leaky coaxial cable 13 is covered with the radio wave shielding sheet 7 and not covered when moving in the −X direction. It may be.

  The leaky coaxial cable 14 shown in FIG. 6 is an existing leaky coaxial cable 14a in which the periodic slot 6 is provided on the outer conductor for the section A, but for the section B, the leaky coaxial cable 14 is different from the leaky coaxial cable. This is a gain antenna cable 14b in which the end of the leaky coaxial cable 14a and the base end of the low gain antenna cable 14b are connected by a cable connector 8.

  The low gain antenna cable 14b has a larger coupling loss than the leaky coaxial cable 14a. Therefore, in section B, the reception level of the leaked radio wave received by the client terminal 5 from the leaky coaxial cable 14 can be lowered to a level at which the client terminal 5 starts roaming processing.

  Note that a normal coaxial cable may be used instead of the low gain antenna cable 14b, and wireless communication may be performed using a naturally leaked radio wave. Also in this case, in the section B, the reception level of the leaked radio wave received by the client terminal 5 from the leaky coaxial cable 14 can be lowered to a level at which the client terminal 5 starts roaming processing.

[Second Embodiment]
FIG. 7 is a conceptual diagram of a radio communication system according to the second embodiment. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 1, and the detailed description is abbreviate | omitted.

  As shown in FIG. 7, in the wireless communication system of the second embodiment, the first access point 2 has a predetermined length from the terminal end to the base end of the first leaky coaxial cable 1 used as an antenna. The portion is bent in a direction in which the distance from the antenna of the client terminal 5 moving along the first leaky coaxial cable 1 is separated. The portion where the first leaky coaxial cable 1 is bent corresponds to the section B of the leaky coaxial cables 11 to 14 shown in FIGS. However, like the leaky coaxial cables 11 to 14, the coupling loss in the section B is not made larger than that in the section A.

  In the second embodiment, the portion corresponding to the section B is bent in a direction in which the distance from the antenna of the client terminal 5 moving along the first leaky coaxial cable 1 is away from the first leak. The reception level of the leaked radio wave received from the coaxial cable can be lowered to a level at which the client terminal 5 starts the roaming process. As a result, it is possible to prevent the communication from becoming unstable when the client terminal 5 switches the connection destination access point by roaming, so that the real-time property of the communication can be stably maintained.

[Third Embodiment]
FIG. 8 is a conceptual diagram of a wireless communication system according to the third embodiment. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 1, and the detailed description is abbreviate | omitted.

  As shown in FIG. 8, in the wireless communication system of the third embodiment, the second end of the first leaky coaxial cable 1 is overlapped with the end of the second leaky coaxial cable 3 so that the second end of the second leaky coaxial cable 3 overlaps. An access point 4 is arranged. Incidentally, in the same manner as in the first embodiment, the first leaky coaxial cable 1 is connected to the client terminal 5 from the first leaky coaxial cable 1 over a predetermined length (section B) from the terminal end to the base end. The reception level of the leaked radio wave to be received is lowered to a level at which the client terminal 5 starts roaming processing.

  As described above, by overlapping the base end portion of the second leaky coaxial cable 3 with the end portion of the first leaky coaxial cable 1, it is surely switched to the second access point 4 when roaming is performed. Thus, more stable roaming can be performed.

  In each of the above embodiments, a wireless communication system in which two access points 2 and 4 are arranged is illustrated. However, each access point is also provided for a wireless communication system in which three or more access points are arranged. Decrease the reception level of leaked radio waves received from the leaky coaxial cable by the mobile station from the end of the leaky coaxial cable connected to the base to a level at which the mobile station starts roaming processing. This is possible.

  In addition, although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

Hereinafter, other inventions described in this embodiment will be additionally described.
[Appendix 1]
A first access point to which the first leaky coaxial cable is connected and used as an antenna, and a second access point that is disposed in the vicinity of the terminal portion of the first leaky coaxial cable and that connects to the second leaky coaxial cable and serves as an antenna. A wireless communication system that performs wireless communication with the mobile station that moves along the first or second leaky coaxial cable via the first or second access point. Decreasing the reception level of leaked radio waves received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the leaky coaxial cable to a level at which the mobile station starts roaming processing A wireless communication system that further covers the periphery of the first leaky coaxial cable from the terminal end to the base end with a radio wave shield over a predetermined length.

[Appendix 2]
A first access point to which the first leaky coaxial cable is connected and used as an antenna, and a second access point that is disposed in the vicinity of the terminal portion of the first leaky coaxial cable and that connects to the second leaky coaxial cable and serves as an antenna. A wireless communication system that performs wireless communication with the mobile station that moves along the first or second leaky coaxial cable via the first or second access point. Decreasing the reception level of leaked radio waves received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the leaky coaxial cable to a level at which the mobile station starts roaming processing The first leaky coaxial cable has a portion extending over a predetermined length from the terminal end to the base end, and a low gain antenna cable different from the leaky coaxial cable. Wireless communication system.

[Appendix 3]
A first access point to which the first leaky coaxial cable is connected and used as an antenna, and a second access point that is disposed in the vicinity of the terminal portion of the first leaky coaxial cable and that connects to the second leaky coaxial cable and serves as an antenna. A wireless communication system that performs wireless communication with the mobile station that moves along the first or second leaky coaxial cable via the first or second access point. Decreasing the reception level of leaked radio waves received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the leaky coaxial cable to a level at which the mobile station starts roaming processing In the first leaky coaxial cable, a portion extending over a predetermined length from the terminal end to the base end is a wireless communication device in which a coaxial cable different from the leaky coaxial cable is used. System.

[Appendix 4]
A first access point to which the first leaky coaxial cable is connected and used as an antenna, and a second access point that is disposed in the vicinity of the terminal portion of the first leaky coaxial cable and that connects to the second leaky coaxial cable and serves as an antenna. A wireless communication system that performs wireless communication with the mobile station that moves along the first or second leaky coaxial cable via the first or second access point. Decreasing the reception level of leaked radio waves received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the leaky coaxial cable to a level at which the mobile station starts roaming processing In the first leaky coaxial cable, a portion of the first leaky coaxial cable extending along a predetermined length from the terminal end to the base end moves along the first leaky coaxial cable. Wireless communication system where the distance between the antenna of the station are bent in a direction away.

[Appendix 5]
A first access point to which the first leaky coaxial cable is connected and used as an antenna, and a second access point that is disposed in the vicinity of the terminal portion of the first leaky coaxial cable and that connects to the second leaky coaxial cable and serves as an antenna. A wireless communication system that performs wireless communication with the mobile station that moves along the first or second leaky coaxial cable via the first or second access point. Decreasing the reception level of leaked radio waves received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the leaky coaxial cable to a level at which the mobile station starts roaming processing And the second access point is arranged so that the base end of the second leaky coaxial cable overlaps with the terminal end of the first leaky coaxial cable Line communication system.

[Appendix 6]
A leaky coaxial cable of a wireless communication system comprising a plurality of access points each connected to a leaky coaxial cable as an antenna, and performing wireless communication with the mobile station moving along the leaky coaxial cable via each access point The mobile station receives a portion extending over a predetermined length from the terminal end to the base end as a low gain antenna cable different from the leaky coaxial cable over the predetermined length from the leaky coaxial cable. A leaky coaxial cable that reduces a reception level of leaked radio waves to a level at which the mobile station starts roaming processing.

[Appendix 7]
A leaky coaxial cable of a wireless communication system comprising a plurality of access points each connected to a leaky coaxial cable as an antenna, and performing wireless communication with the mobile station moving along the leaky coaxial cable via each access point The portion extending over a predetermined length from the terminal end to the base end is a coaxial cable different from the leaky coaxial cable, and the mobile station receives leaked radio waves from the leaky coaxial cable over the predetermined length. A leaky coaxial cable that reduces a reception level to a level at which the mobile station starts roaming processing.

[Appendix 8]
A leaky coaxial cable of a wireless communication system comprising a plurality of access points each connected to a leaky coaxial cable as an antenna, and performing wireless communication with the mobile station moving along the leaky coaxial cable via each access point A portion extending over a predetermined length from the terminal end to the base end is bent in a direction away from the antenna of the mobile station moving along the leaky coaxial cable, over the predetermined length A leaky coaxial cable that reduces the reception level of leaked radio waves received by the mobile station from the leaky coaxial cable to a level at which the mobile station starts roaming processing.

  DESCRIPTION OF SYMBOLS 1 ... 1st leaky coaxial cable, 2 ... 1st access point, 3 ... 2nd leaky coaxial cable, 4 ... 2nd access point, 5 ... Client terminal.

Claims (7)

A first access point to which the first leaky coaxial cable is connected and used as an antenna, and a second access point that is disposed in the vicinity of the terminal portion of the first leaky coaxial cable and that connects to the second leaky coaxial cable and serves as an antenna. A wireless communication system that performs wireless communication with a mobile station that moves along the first or second leaky coaxial cable and the first or second access point,
The mobile station starts roaming processing for the reception level of leaked radio waves received by the mobile station from the first leaky coaxial cable over a predetermined length from the terminal end to the base end of the first leaky coaxial cable. A wireless communication system, characterized in that the communication system is reduced to a level to achieve.   2. The wireless communication system according to claim 1, wherein the first leaky coaxial cable has a coupling loss larger than other portions over a predetermined length from the terminal end to the base end.   2. The wireless communication system according to claim 1, wherein the first leaky coaxial cable has a slot size smaller than other portions over a predetermined length from the terminal end to the base end.   2. The wireless communication system according to claim 1, wherein the first leaky coaxial cable has a slot interval wider than another portion over a predetermined length from the terminal end to the base end. A leaky coaxial cable of a wireless communication system comprising a plurality of access points each connected to a leaky coaxial cable as an antenna, and performing wireless communication with the mobile station moving along the leaky coaxial cable via each access point There,
The coupling loss over a predetermined length from the terminal end to the base end is made larger than that of other parts, and the reception level of the leaked radio wave that the mobile station receives from the leaky coaxial cable over the predetermined length is A leaky coaxial cable characterized in that the mobile station is lowered to a level at which roaming processing starts. A leaky coaxial cable of a wireless communication system comprising a plurality of access points each connected to a leaky coaxial cable as an antenna, and performing wireless communication with the mobile station moving along the leaky coaxial cable via each access point There,
The size of the slot is made smaller than other parts over a predetermined length from the terminal end to the base end, and the reception level of the leaked radio wave that the mobile station receives from the leaky coaxial cable over the predetermined length, The leaky coaxial cable, wherein the mobile station is lowered to a level at which the mobile station starts roaming processing. A leaky coaxial cable of a wireless communication system comprising a plurality of access points each connected to a leaky coaxial cable as an antenna, and performing wireless communication with the mobile station moving along the leaky coaxial cable via each access point There,
The reception level of the leaked radio wave that the mobile station receives from the leaky coaxial cable is extended over the predetermined length by extending the slot interval over a predetermined length from the terminal end to the base end, The leaky coaxial cable, wherein the mobile station is lowered to a level at which the mobile station starts roaming processing.

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