JP6558963B2 - Wireless communication system and design method thereof - Google Patents

Description

  The present invention relates to a wireless communication system and a design method thereof.

  A leaky coaxial cable (LCX: Leaky Coaxial Cable) is a cable type antenna in which a hole called a slot is provided in an outer conductor of a coaxial cable. In LCX, electromagnetic waves inside the cable can be radiated (transmitted) to the outside of the cable and electromagnetic waves outside the cable can be taken into (received) inside the cable through such a slot.

  For this reason, LCX is particularly effective for use in an environment where the communication environment is long and there are many obstacles such as metal bodies. For example, an electromagnetic wave insensitive zone is likely to occur in a winding tunnel or a place where many metal objects exist. In such a place, when a general transceiver with an antenna is used, a large number of transceivers must be installed.

  On the other hand, when LCX is used, a large number of slots periodically arranged in the extending direction of LCX function as antennas. In this case, a large number of antennas are arranged in the extending direction of LCX. Thereby, it is possible to suppress the generation of an insensitive zone of electromagnetic waves in an environment in which many obstacles such as a long and slender metal body are present by simply installing one LCX. Also, the LCX installation work can be carried out very easily because it is only necessary to route the LCX as compared with the above-described general installation of a transceiver with an antenna.

  By the way, with the recent widespread use of wireless local area networks (LANs), there are increasing opportunities to use LCX as an antenna for wireless LAN access points. Furthermore, recently, an LCX is laid in the height direction (vertical direction) while penetrating through a multi-story floor, and a wireless LAN communication environment is constructed throughout the building (for example, see Patent Document 1). reference.).

  When LCX is laid vertically in a state where it penetrates the floor of the multi-story floor, the use length of LCX as a whole building can be reduced compared with the case where the conventional LCX is laid horizontally on the ceiling of the floor, etc. it can. For this reason, there is an advantage that a wireless LAN communication environment can be constructed in the entire building at low cost.

  In addition, when laying multiple LCXs side by side through multiple floors, the access point (AP) can be installed and maintained on the bottom or top floor of the multi-story floor for ease of installation and maintenance work. In many cases, an AP is installed.

JP 2014-236399 A

  By the way, the intensity of the radio wave radiated from the LCX is attenuated and weakened from a terminal that inputs a signal (hereinafter referred to as an input terminal) toward a terminal on the opposite side (hereinafter referred to as an opposite terminal). . For this reason, in the LCX connected to the AP, the communication area becomes narrower from the base end (input terminal) side toward the front end (opposite terminal) side.

  In addition, even when a plurality of LCXs are laid side by side while penetrating a plurality of floors, if the APs are installed together on the lowermost floor or the uppermost floor, they are covered by the LCX connected to each AP as the distance from the AP increases. Communication area to be narrowed.

  For this reason, it is necessary to overlap each other's communication areas between LCXs adjacent to each other, and the interval between adjacent LCXs must be adjusted so as to approach each other according to the narrow communication area on the opposite terminal side. As a result, there has been a problem that the number of LCXs used to construct a wireless LAN communication environment in the entire building increases.

  One aspect of the present invention has been proposed in view of such conventional circumstances, and can efficiently use each communication area of a plurality of leaky coaxial cables laid in parallel with each other. An object of the present invention is to provide a wireless communication system and a design method thereof.

  In order to achieve the above object, a wireless communication system according to one aspect of the present invention includes a plurality of leaky coaxial cables laid in parallel with each other and connected to one end side or the other end side of each leaky coaxial cable. A plurality of leaky coaxial cables, and the access point is connected to one end side of one leaky coaxial cable adjacent to each other and the other end side of the other leaky coaxial cable, respectively. The one leaky coaxial cable and the other leaky coaxial cable cover at least a communication area between the one leaky coaxial cable and the other leaky coaxial cable. And an interval between the other leaky coaxial cable is set.

  In the wireless communication system, the boundary line of the communication area covered by the one leaky coaxial cable and the boundary line of the communication area covered by the other leaky coaxial cable are in contact with each other. The space | interval between the leaky coaxial cable and said other leaky coaxial cable may be set.

  Moreover, the said radio | wireless communications system WHEREIN: The structure laid in the height direction in the state penetrated between each floor of a multi-storey building may be sufficient as these leaky coaxial cables.

  The wireless communication system may be configured such that two or more leaky coaxial cables are connected to the access point via a distributor.

  Further, the wireless communication system may include a communication cable that electrically connects the plurality of access points and the upper line.

  The wireless communication system may be configured such that two or more communication cables are connected to the upper line via a hub or a router.

  The wireless communication system may use a composite cable in which the communication cable and the leaky coaxial cable are integrated.

  The wireless communication system design method according to one aspect of the present invention includes a plurality of leaky coaxial cables laid in parallel with each other and a plurality of leaky coaxial cables connected to one end side or the other end side of each leaky coaxial cable. A plurality of leaky coaxial cables, one end side of one leaky coaxial cable adjacent to each other, and the other end side of the other leaky coaxial cable, Each of the access points is connected, and the one leaky coaxial cable and the other leaky coaxial cable cover at least a communication area between the one leaky coaxial cable and the other leaky coaxial cable, An interval between the one leaky coaxial cable and the other leaky coaxial cable is set.

  As described above, according to one aspect of the present invention, there is provided a wireless communication system and a design method thereof that can efficiently use each communication area of a plurality of leaky coaxial cables laid in parallel with each other. Is possible.

1 is a perspective view showing a multi-storey building in which a wireless communication system according to an embodiment of the present invention is constructed. It is a perspective view which shows the cross-section of LCX used with the wire communication system shown in FIG. Is a plan view showing the sectional structure of the integrated LCX and the support wire. It is a perspective view which shows the form with which LCX was connected to AP. It is a top view which shows the composite cable with which LCX and the communication cable were integrated. It is a top view which shows the example of the connection form of LCX and AP. It is a graph which shows the directivity in the cable cross section view of LCX in the case of 10D size. It is a graph which shows the directivity in the cable cross section view of LCX in the case of 20D size. It is a graph which shows the directivity in the cable cross section view of LCX in the case of 33D size. It is a side view which shows typically the communication area of 1st LCX and 2nd LCX in each floor of a multi-storey building. It is a top view which shows typically the communication area of 1st LCX and 2nd LCX in the lowest floor of a multi-storey building. It is a top view which shows typically the communication area of 1st LCX and 2nd LCX in the top floor of a multi-storey building. It is a side view which shows typically the communication area of 1st LCX and 2nd LCX in each floor of the multilayered floor building used as a comparative example. It is a top view which shows typically the communication area of 1st LCX and 2nd LCX in the lowest floor of the multi-storey building used as a comparative example. It is a top view which shows typically the communication area of 1st LCX and 2nd LCX in the top floor of the multi-storey building used as a comparative example. It is a side view which shows another structural example of a radio | wireless communications system. It is a schematic diagram which shows the standard model of a 1st Example. It is a graph which shows the communication area of 1st LCX in case of D = 100m, and 2nd LCX. It is a graph which shows the communication area of 1st LCX in case of D = 50m, and 2nd LCX. It is a graph which shows the communication area of 1st LCX in case of D = 20m, and 2nd LCX. It is a graph which shows the case where the communication area of 1st LCX and the communication area of 2nd LCX touch mutually. It is a graph which shows the relationship between the space | interval D at the time of inputting a signal from the reverse direction with respect to 1st LCX and 2nd LCX, and length when the signal is input from the same direction. It is a graph which shows the ratio of the space | interval when a signal is input from the reverse direction with respect to 1st LCX and 2nd LCX, and a signal is input from the same direction. It is a graph which shows the result of having measured the field intensity when a signal is inputted from the reverse direction to the first LCX and the second LCX in the second embodiment and when the signal is inputted from the same direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent. In addition, the materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not necessarily limited thereto, and can be appropriately modified and implemented without departing from the scope of the invention. .

  First, as an embodiment of the present invention, for example, a radio communication system 100 shown in FIG. 1 and a design method thereof will be described. FIG. 1 is a perspective view showing a multi-story building 200 in which the wireless communication system 100 is constructed.

  As shown in FIG. 1, the wireless communication system 100 according to the present embodiment includes a plurality of leaky coaxial cables (parallel to each other) in a multi-storey building 200 such as an office building that penetrates between floors 201 of each floor. Hereinafter, LCX) 1 is laid in the height direction (vertical direction) to construct a wireless LAN communication environment in the entire building.

  Here, LCX1 used in the present embodiment will be described with reference to FIG. FIG. 2 is a perspective view showing a cross-sectional structure of the LCX 1 used in the present embodiment.

  As shown in FIG. 2, the LCX 1 includes a linear center conductor 2, an insulator 3 concentrically covering the center conductor 2, a plurality of insulators 3 concentrically covered and periodically arranged in the extending direction. The outer conductor 5 is provided with an open slot 4 and a sheath 6 that covers the outer conductor 5 concentrically.

  The center conductor 2 and the outer conductor 5 are often made of copper having low electrical resistance in order to keep transmission loss low, but aluminum, silver, or the like may be used. Further, a copper-coated aluminum wire may be used as the center conductor 2. The central conductor 2 may be a single wire or a stranded wire. For the insulator 3, polyethylene having a low dielectric loss (tan δ) is used for the purpose of reducing transmission loss in a high frequency band. Furthermore, in order to reduce tan δ, foamable polyethylene containing fine bubbles inside the insulator 3 may be used. For the sheath 6, polyethylene, vinyl chloride, flame retardant polyethylene, or the like is used in order to prevent damage to the LCX 1. Further, the heat-resistant LCX 1 has a structure (not shown) in which a glass fiber tape is wound around the insulator 3 so that the center conductor 2 and the outer conductor 5 are not short-circuited immediately even if burned. It may be adopted.

  The plurality of slots 4 are arranged in a straight line at a constant pitch P in the extending direction of the LCX 1 and open in the same direction. The shape of the slot 4 is not particularly limited, and may be, for example, a round hole or a long hole. In the present embodiment, as the zigzag type slots 4, long holes that are oblique with respect to the extending direction are arranged side by side while alternately changing the oblique directions. Further, the vertical slot 4 may have a configuration (not shown) in which long holes perpendicular to the extending direction are arranged side by side.

Further, as shown in FIG. 3, the LCX 1 may have a structure in which the LCX 1 is integrally covered with a support sheath 7 that supports the LCX 1 and a common sheath 6. FIG. 3 is a plan view showing a cross-sectional structure of the LCX 1 integrated with the support wire 7.

  In the wireless communication system 100 of the present embodiment, as shown in FIG. 4, by connecting one end side or the other end side of the LCX 1 to an access point (hereinafter referred to as AP) 50, the LCX 1 is used for a wireless LAN access point. Functions as an antenna (cable antenna). Specifically, a connector 8 for connecting to the antenna terminal of the AP 50 is attached to one end (or the other end) of the LCX 1. A termination resistor 9 is attached to the other end (or one end) of the LCX 1.

  In the wireless communication system 100 of this embodiment, as shown in FIGS. 1 and 4, the connector 8 of the LCX 1 and the antenna terminal of the AP 50 are connected via a connection cable 20. In the wireless communication system 100 of the present embodiment, two or more LCXs 1 may be connected to the AP 50 via the distributor 30.

  The AP 50 is connected to a hub (HUB) 31 via a communication cable 40, and is further connected from the hub 31 to an upper line (not shown). In the wireless communication system 100 of this embodiment, a router may be used instead of the hub (HUB) 31.

  As the communication cable 40, for example, LAN cables of Category 5, Category 6, Category 6A, Category 7 conforming to ANSI / TIA / EIA-568, ISO / IEC 11801, or JIS X 5150 can be used.

  Further, in the wireless communication system 100 according to the present embodiment, as illustrated in FIG. 5, a composite cable 60 in which the LCX 1 and the communication cable 40 are integrated may be used. The composite cable 60 has a structure in which the LCX 1 and the communication cable 40 are integrally covered with a common sheath 6 in a state where they are parallel to each other.

  Specifically, the sheath 6 includes a first covering portion 6a that covers the communication cable 40 side, a second covering portion 6b that covers the LCX1 side, a first covering portion 6a, and a second covering portion 6b. And a connecting portion 6c for connecting the two.

  In the composite cable 60 of the present embodiment, the plurality of slots 4 of the LCX 1 are opened in a direction different from the direction toward the communication cable 40. In particular, the plurality of slots 4 are preferably open in a direction opposite to the direction toward the communication cable 40. As a result, in the composite cable 60 of this embodiment, the communication cable 40 does not overlap the slot 4 side of the LCX 1, so that electromagnetic waves transmitted and received through the slot 4 are not blocked by the communication cable 40 and communicate with the antenna performance of the LCX 1. It is possible to prevent the cable 40 from having an adverse effect.

  In general LCX, the position of the slot cannot be confirmed by the sheath covering the outer conductor. On the other hand, in the composite cable 60 of the present embodiment, the position of the slot 4 covered with the second covering portion 6b can be recognized from the positional relationship between the LCX 1 and the communication cable 40.

Here, in the composite cable 60, the end on the side of the communication cable 40 is preferably longer than the end on the side of the LCX 1 at the end on the side connected to the AP 50. In this case, since the communication cable 40 has a lower bending rigidity than the LCX 1 and is easily bent, the connection with the AP 50 is facilitated by lengthening the end of the communication cable 40 .

  On the other hand, since the LCX 1 has higher bending rigidity than the communication cable 40 and is difficult to bend, the LCX 1 and the AP 50 can be connected via the connection cable 20 having lower bending rigidity (easy to bend) than the LCX 1 described above. Good. Note that the connection cable 20 is not necessarily essential, and may be omitted if the connector 8 of the LCX 1 can be directly connected to the AP 50.

  The connection form between the LCX 1 and the AP 50 is defined by ARIB STD-T33, ARIB STD-T66, ARIB STD-T71, etc. in the ARIB standard. Moreover, as a connection form of LCX1 and AP50, the connection form shown to Fig.6 (a)-(c) can be illustrated. 6A to 6C are plan views showing examples of connection forms between the LCX 1 and the AP 50. FIG.

  Specifically, the connection form shown in FIG. 6A is a “single configuration” in which one LCX 1 is connected to one AP 50. On the other hand, the connection form shown in FIG. 6B is a “branch configuration” in which a plurality (two in the present embodiment) of LCXs 1 are connected to one AP 50 via the distributor 30. On the other hand, the connection form shown in FIG. 6C is a “grading configuration” in which a plurality of LCXs 1 are connected in series to one AP 50.

  Here, when a configuration in which LCX 1 is connected to one AP 50 is defined as one system, an area where the intensity of radio waves radiated from LCX 1 of one system is equal to or higher than a predetermined value (hereinafter simply referred to as “communication area”). , Depending on the length of LCX1. The length of LCX1 is limited by the transmission loss of LCX1. That is, when the transmission loss of LCX1 is large, the usable limit length of LCX1 is shortened. Conversely, when the transmission loss of LCX1 is small, the usable limit length of LCX1 becomes long. Therefore, the system length in the radio communication system 100 is limited by the characteristics of the LCX1.

  An example of the system length in the radio communication system 100 having a single configuration is as follows. LCX1 is 5D (the number before D indicates the approximate outer diameter [unit: mm] of the insulator 3). The system length for about 30 m and 10D size is about 70 m, and the system length for 20D size is about 110 m. On the other hand, when an example of the system length in the wireless communication system 100 with a branch configuration is shown, the system length when the LCX1 is 5D size is about 40 m, the system length when the 10D size is about 110 m, and the system length when the 20D size is About 150m.

  In addition, FIG. 7, FIG. 8, and FIG. 9 show the results of calculating the directivity of the LCX1 in the cable cross-sectional view for each of the 10D size, the 20D size, and the 33D size. In the graphs shown in FIGS. 7, 8, and 9, the circumferential axis indicates the angle, and the vertical axis indicates the fluctuation (dB) of the normalized radiation intensity. The frequency used in this simulation is 2.4 GHz. Further, the outer diameter of LCX1 in the case of 10D size shown in FIG. 7 is about 16 mm, the outer diameter of LCX1 in the case of 20D size shown in FIG. 8 is about 29 mm, and the outer diameter of LCX1 in the case of 33D size shown in FIG. About 41 mm.

  As shown in FIGS. 7, 8, and 9, it can be seen that LCX1 has higher directivity in cable cross-sectional view as the size increases.

  By the way, in LCX1 connected to AP50, as shown in FIG. 4, the communication area W covered by this LCX1 becomes narrower as it goes from the base end (input terminal) side to the front end (opposite terminal) side.

  Here, the communication area W refers to a communicable area inside the boundary line in a communication device used in the wireless communication system 100, with the minimum value of communicable radio wave intensity as a boundary line. That is, the communication area W is an area that satisfies the radio wave intensity necessary for the communication device to perform wireless communication. Since the communication area W covered by the LCX1 depends on the length of the LCX1 described above, the communication area W is narrowed from the connection position with the AP 50 toward the tip of the LCX1.

  Therefore, in the wireless communication system 100 and the design method thereof according to the present embodiment, as shown in FIGS. 10, 11, and 12, one of the plurality of LCX1s adjacent to each other (hereinafter referred to as a first LCX1A). ) And one end side of the other LCX1 (hereinafter referred to as second LCX1B), respectively, and AP50 is connected to each other, and the first LCX1A and the second LCX1B are at least the first LCX1A and The interval D between the first LCX 1A and the second LCX 1B is set so as to cover the communication area between the second LCX 1B.

  FIG. 10 is a side view schematically showing communication areas W1, W2 between the first LCX 1A and the second LCX 1B in each floor 201 of the multi-story building 200. FIG. 11 is a plan view schematically showing communication areas W1, W2 between the first LCX 1A and the second LCX 1B on the lowest floor of the multi-story building 200. FIG. FIG. 12 is a plan view schematically showing communication areas W1, W2 between the first LCX 1A and the second LCX 1B on the top floor of the multi-story building 200. FIG.

  In the following description, the communication area covered by the first LCX 1A is the communication area W1 of the first LCX 1A, and the communication area covered by the second LCX 1B is the communication area W2 of the second LCX 1B. A communication area covered by the communication area W1 of one LCX 1A and the communication area W2 of the second LCX 1B will be described.

  Further, the interval D between the first LCX 1A and the second LCX 1B refers to the distance between the LCXs 1A and 1B having the closest positional relationship among the adjacent LCXs 1. In the following description, one LCX1 is identified as a first LCX1A, and the other LCX1 is identified as a second LCX1B.

  In the wireless communication system 100 and the design method thereof according to the present embodiment, as shown in FIGS. 10, 11, and 12, the AP 50 connected to one end side of each first LCX 1 </ b> A among the plurality of LCXs 1 is the lowest floor. AP50 connected to the other end of each second LCX 1B is installed on the top floor. The AP 50 installed on the top floor is connected to a hub 31 (or router) set on the bottom floor side via a communication cable 40 laid in a state of penetrating between the floors 201 of each floor. . Therefore, the composite cable 60 in which the above-described LCX1 (second LCX1B) and the communication cable 40 are integrated can be connected to the AP 50 installed on the top floor.

  In this case, the communication area W1 of the first LCX 1A is narrowed from the bottom floor toward the top floor. Conversely, the communication area W2 of the second LCX 1B is narrowed from the top floor to the bottom floor. Accordingly, since the overlapping area necessary for overlapping the communication areas W1 and W2 can be reduced, it is possible to ensure a large interval D between the first LCX1A and the second LCX1B adjacent to each other. .

  On the other hand, in order to compare with the wireless communication system 100 of the present embodiment, a wireless communication system 100 ′ as a comparative example shown in FIGS. 13, 14, and 15 will be described. 13, 14, and 15 show a wireless communication system 100 ′ as a comparative example. 13, FIG. 14 and FIG. 15 are drawings corresponding to FIG. 10, FIG. 11 and FIG. 12, respectively, showing the wireless communication system 100 of the present embodiment.

  In the following description, the communication area covered by the first LCX1A ′ is the communication area W1 ′ of the first LCX1A ′, and the communication area covered by the second LCX1B ′ is the communication of the second LCX1B ′. As the area W2 ′, a communication area covered by the communication area W1 ′ of the first LCX 1A ′ and the communication area W2 ′ of the second LCX 1B ′ will be described.

  Further, the distance D ′ between the first LCX 1A ′ and the second LCX 1B ′ refers to the distance between the LCX 1A ′ and 1B ′ having the closest positional relationship among the adjacent LCXs 1. . In the following description, one LCX1 is identified as a first LCX1A ', and the other LCX1 is identified as a second LCX1B'.

  As shown in FIGS. 13, 14, and 15, the wireless communication system 100 ′ as a comparative example includes a first LCX 1 A ′ adjacent to each other among a plurality of LCX 1 ′ and a second LCX 1 B ′. The first LCX1A ′ and the second LCX1B are connected such that the AP50 is connected to one end side, and the communication area W1 ′ of the first LCX1A ′ and the communication area W2 ′ of the second LCX1B ′ overlap each other. This is a case where an interval D between 'and' is set.

  For this reason, in the wireless communication system 100 ′ as the comparative example, among the plurality of LCX1 ′, the AP50 connected to one end side of each first LCX1A ′ and the one end side of each second LCX1B ′ AP50 is installed in the lowest floor (same floor), respectively.

  In this case, the communication area W1 'of the first LCX 1A' and the communication area W2 'of the second LCX 1B' are narrowed from the lowest floor to the highest floor, respectively. Therefore, in order to overlap the communication areas W1 ′ and W2 ′ with each other so as not to cause a dead zone, the first LCX1A ′ adjacent to each other in accordance with the narrow communication areas W1 ′ and W2 ′ on the top floor side. The distance D ′ between the second LCX 1 B ′ and the second LCX 1 B ′ must be adjusted in a direction to approach each other.

  As a result, on the contrary, the overlapping area where the communication areas W1 'and W2' are overlapped becomes larger on the lowermost floor, and the respective communication areas W1 'and W2' cannot be used efficiently. In addition, the number of LCXs 1 'used to construct a wireless LAN communication environment in the entire multi-storey building 200 is also increased.

  As described above, in the wireless communication system 100 and the design method thereof according to the present embodiment, the communication area W1 between the first LCX1A and the second LCX1B adjacent to each other while ensuring a large distance D between the first LCX1A and the second LCX1B. , W2 can be overlapped with each other, so that the communication areas W1, W2 can be used efficiently. In addition, it is possible to reduce the number of LCXs 1 used to construct a wireless LAN communication environment in the entire multi-story building 200. Therefore, since the number of APs 50 installed can be reduced, the introduction cost of the entire system can be reduced.

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the wireless communication system 100 and the design method thereof, as shown in FIG. 16, among the plurality of LCX1, the AP 50 connected to one end side of each first LCX 1A and the other end side of each second LCX 1B It is also possible to adopt a configuration in which the APs 50 connected to are respectively installed on the same floor (the lowest floor in the present embodiment).

  In this case, the other end side of each second LCX 1B located on the top floor and the AP 50 installed on the bottom floor are connected via the connection cable 20. Although not shown, a composite cable in which the LCX1 (second LCX1B) and the connection cable 20 are integrated may be used.

  In the case of the configuration shown in FIG. 16, a plurality of APs 50 can be installed together on the lowest floor, which is advantageous in terms of AP 50 mounting work and maintenance work.

  In the above-described embodiment, a LAN cable is used as the communication cable 40, but various other communication cables can be used. For example, examples of communication cables other than LAN cables include optical cables and coaxial cables. When these communication cables are connected to the AP 50, they cannot be directly connected to the AP 50. Therefore, after conversion to a LAN cable using a media converter or the like, it is possible to connect to the AP 50.

  Further, the wireless communication system and the design method to which the present invention is applied are not limited to the case where the above-described wireless LAN environment is constructed, and can be applied to all wireless communication using LCX1. For this reason, for example, the same effect can be obtained even if the use is different from the wireless LAN, the frequency band, and the laying form (for example, outside the building or when laying in the horizontal direction).

  In addition, a wireless communication system and a design method thereof to which the present invention is applied include, for example, energy monitoring systems such as a building energy monitoring system (BEMS) and a residential energy monitoring system (HEMS). The present invention is also applicable when constructing (EMS).

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

(First embodiment)
In the first embodiment, a standard model as shown in FIG. 17 is set. FIG. 17 shows an XY coordinate system with the origin at (X, Y) = (0, 0). In this coordinate system, the first LCX 1A and the second LCX 1B are arranged in parallel to each other. is there. The first LCX 1A has a length of H (m), one end is located at the origin, the other end is located at the coordinates (0, H), and is arranged along the Y axis from the origin to the coordinates (0, H). . The second LCX 1B also has a length H (m), one end thereof is located at the coordinate (D, 0), the other end is located at the coordinate (D, H), and is arranged along the line X = D. Yes. The first LCX 1A and the second LCX 1B are adjacent to each other, and the distance between them is D (m).

  The signal source of the first LCX 1A is the origin (0, 0), and a signal is input from the origin (0, 0) toward the coordinates (0, H). The signal source of the second LCX 1B is (D, H), and a signal is input from the coordinates (D, H) to the coordinates (D, 0). Therefore, the input directions of the signals to the first LCX 1A and the second LCX 1B are opposite to each other as indicated by arrows in FIG.

In such a model, the following parameters were set.
<Parameter>
Pd (dBm): The intensity of the radio wave radiated from the first LCX 1A at the coordinates P (X, Y).
Pu (dBm): The intensity of the radio wave radiated from the second LCX 1B at the coordinate P (X, Y).
P _in (dB): Power of a signal input to the first LCX 1A and the second LCX 1B.
P _CL (dB): Coupling loss at a point 1.5 m away from the first LCX1A and the second LCX1B.
α (dB / m): Transmission loss of the first LCX 1A and the second LCX 1B.

  In the ideal space, the radio wave intensity at the coordinate P of the first LCX 1A is expressed by the following formula (1).

  On the other hand, the radio wave intensity at the coordinate P of the second LCX 1B is expressed by the following formula (2).

  Here, when the above formulas (1) and (2) are respectively arranged, the following formulas (3) and (4) are obtained.

  Conditions for good wireless LAN communication vary depending on the type and size of data to be transmitted / received and the radio wave intensity at the reception limit. In the present embodiment, a case where the minimum value of radio wave intensity with which a communication device can communicate is -70 dBm will be described as an example. That is, in this embodiment, an area where the radio wave intensity is −70 dBm or more is defined as a communication area.

Specifically, in this embodiment, the radio field strengths Pd and Pu at the coordinates P are assumed to be −70 dBm, and the distance D (m) between the first LCX 1A and the second LCX 1B is set to 100, 50, and 20, respectively. The communication area when changing was calculated. The calculation results are shown in FIG. 18, FIG. 19, and FIG. The first LCX 1A and the second LCX 1B used in this calculation are 10D-sized LCX, and the parameters are set as follows.
H = 70m
P _in = + 5 dBm
P _CL = 58 dB
α = 0.18 dB / m

  FIG. 18 shows the case where the first LCX1A is arranged at the position of X = 0 and the second LCX1B is arranged at the position of X = 100, and the interval D between the first LCX1A and the second LCX1B is , 100 m.

  As shown in FIG. 18, when D = 100 m, the communication area W1 of the first LCX 1A and the communication area W2 of the second LCX 1B did not overlap. In this case, the communication environment becomes unstable between the first LCX 1A and the second LCX 1B.

  FIG. 19 shows the case where the first LCX1A is arranged at the position of X = 0 and the second LCX1B is arranged at the position of X = 50. The distance D between the first LCX 1A and the second LCX 1B is 50 m.

  As shown in FIG. 19, in the case of D = 50 m, an area where the communication area W1 of the first LCX 1A and the communication area W2 of the second LCX 1B overlap and an area which does not overlap occur. In this case, a good communication environment is obtained in the overlapping area, but the communication environment becomes unstable in the non-overlapping area.

  FIG. 20 shows a case where the first LCX 1A is arranged at the position of X = 0 and the second LCX 1B is arranged at the position of X = 20. The distance D between the first LCX 1A and the second LCX 1B is 20 m.

As shown in FIG. 20, when D = 20 m, the communication area W1 of the first LCX 1A and the communication area W2 of the second LCX 1B overlap in all areas, and there is no dead zone. In this case, although the communication environment is good in all areas, it cannot be said that the communication area W1 of the first LCX 1A and the communication area W2 of the second LCX 1B are effectively used.

  From the above calculation results, the communication area W1 of the first LCX1A and the communication area W2 of the second LCX1B exist in all regions, and the distance D between the first LCX1A and the second LCX1B Find the condition that maximizes. Specifically, the distance D when the boundary line of the communication area W1 covered by the first LCX 1A and the boundary line of the communication area W2 covered by the second LCX 1B are in contact with each other is obtained. Thereby, the optimal condition of the space | interval D from which a favorable communication environment is obtained in all the areas | regions can be calculated | required, without producing a dead zone.

  In order to obtain the optimum condition of the interval D, in the above formulas (3) and (4), the boundary line of the communication area W1 covered by the first LCX1A and the boundary line of the communication area W2 covered by the second LCX1B The conditions in which and are in contact with each other were determined by the following (5) and (6).

  In addition, A shown in the formulas (5) and (6) is as shown in the following formula (7).

  Differentiating the above equations (5) and (6) yields the following equations (8) and (9).

  When the X coordinate of the contact point between the boundary line of the communication area W1 covered by the first LCX1A and the boundary line of the communication area W2 covered by the second LCX1B is t, the relationship of the following formula (10) is obtained. It is done.

  Accordingly, the distance D when the boundary line of the communication area W1 covered by the first LCX 1A and the boundary line of the communication area W2 covered by the second LCX 1B are in contact with each other is obtained by the following equation (11). Can do.

On the other hand, since the above formulas (5) and (6) have a common contact, the relationship of the following formula (12) is established.

  Accordingly, when t is deleted from the above equations (11) and (12) and rearranged, the following equation (13) is obtained.

  From the above equation (13), the distance D when the boundary line of the communication area W1 covered by the first LCX1A and the boundary line of the communication area W2 covered by the second LCX1B contact each other is obtained by calculation. Can do.

  As a result, under the condition of the above parameter, when D = 35.2 m, the boundary line of the communication area W1 covered by the first LCX1A and the boundary line of the communication area W2 covered by the second LCX1B are I found that they touch each other. FIG. 21 shows the result of calculating the communication area W1 of the first LCX 1A and the communication area W2 of the second LCX 1B at that time.

  Next, the boundary line of the communication area W1 covered by the first LCX1A and the communication covered by the second LCX1B when signals are input to the first LCX1A and the second LCX1B from opposite directions. FIG. 22 shows the calculation result of the distance D between the boundary lines of the area W2 and the length H (m) of the first LCX1A and the second LCX1B. Further, FIG. 22 shows the same calculation result when signals are input from the same direction to the first LCX 1A and the second LCX 1B.

  As shown in FIG. 22, when the length H of the first LCX 1A and the second LCX 1B is 50 m, for example, when signals are input from the same direction, the interval D needs to be 18.9 m or less. . On the other hand, when signals are input from opposite directions, the distance D may be set to 53.3 m or less.

  Next, FIG. 23 shows the result of calculating the ratio of the interval D when signals are input from opposite directions to the interval D when signals are input from the same direction from the results shown in FIG.

  As shown in FIG. 23, it can be seen that the ratio increases as the length H of the first LCX 1A and the second LCX 1B increases. In the case of 10D size LCX, the maximum use length is 70 m, but the ratio when H = 70 m is about 4.3 times. Further, as shown in FIG. 22, the distance D when H = 70 m is about 35.2 m.

  As described above, when the first LCX 1A and the second LCX 1B are laid in the vertical direction in parallel with each other, signals are input to the first LCX 1A and the second LCX 1B from opposite directions. Thus, it is possible to widen the interval D at which a good communication environment is obtained in all areas. Thereby, the laying density of LCX1 per floor can be lowered, and the cost of the entire system can be reduced.

(Second embodiment)
In the second embodiment, the radio communication system 100 according to the embodiment shown in FIGS. 10, 11, and 12 and the radio communication system 100 ′ as a comparative example shown in FIGS. The radio wave intensity in the floor 201 of the building 200 was measured, and the intensity distribution was evaluated.

  Specifically, as shown in FIG. 24, in a nine-story building 200, when signals are input from the opposite direction to the first LCX 1A and the second LCX 1B (the wireless communication system 100 of the embodiment) When the signal is input to the first LCX 1A ′ and the second LCX 1B ′ from the same direction (radio communication system 100 ′ of the comparative example), the radio field intensity is measured at the third floor and the ninth floor, and the intensity distribution is measured. Graphed.

  In FIG. 24, a case where a signal is input from the opposite direction to the first LCX 1A and the second LCX 1B (Example) is shown on the right side in FIG. 24, and the first LCX 1A ′ and the second LCX 1B ′. FIG. 24 shows the case where signals are input from the same direction (comparative example) on the left side of FIG.

  As shown on the right side in FIG. 24, when signals are input from the reverse direction to the first LCX 1A and the second LCX 1B (Example), the first LCX 1A ′ and the second LCX 1B ′ It can be seen that there is less difference in radio wave intensity on the floor 201 of each floor than when signals are input from the same direction (comparative example). This is considered to be because the overlapping areas where the communication areas W1 and W2 of the first LCX 1A and the second LCX 1B are overlapped on the third floor and the ninth floor are almost equal.

  On the other hand, as shown on the left side in FIG. 24, when signals are input from the same direction to the first LCX 1A ′ and the second LCX 1B ′ (comparative example), the first floor A region where the radio wave intensity is high is generated between the LCX 1A ′ and the second LCX 1B ′. This is presumably because the overlapping area where the communication areas W1 'and W2' of the first LCX1A 'and the second LCX1B' overlap each other becomes large.

  On the ninth floor, there is a region where the radio field intensity is low between the first LCX 1A 'and the second LCX 1B'. This is presumably because a region where the communication areas W1 'and W2' of the first LCX 1A 'and the second LCX 1B' do not overlap each other has occurred.

  As described above, when signals are input from the reverse direction to the first LCX 1A and the second LCX 1B (Example), the signals are input from the same direction to the first LCX 1A ′ and the second LCX 1B ′. Compared to the case of input (comparative example), the communication areas W1 and W2 of the first LCX 1A and the second LCX 1B can be efficiently used in each floor 201 of the multi-story building 200. .

  DESCRIPTION OF SYMBOLS 1 ... Leaky coaxial cable (LCX) 1A ... 1st LCX (one leaky coaxial cable) 1B ... 2nd LCX (the other leaky coaxial cable) 2 ... Center conductor 3 ... Insulator 4 ... Slot 5 ... External conductor 6 ... Sheath 6a ... First covering part 6b ... Second covering part 6c ... Connecting part 7 ... Support wire 8 ... Connector 9 ... Terminal resistor 20 ... Connecting cable 30 ... Distributor 31 ... Hub (HUB) or router 40 ... Communication cable 50 ... Access point (AP) 60 ... Composite cable 100 ... Wireless communication system 200 ... Multi-story building 201 ... Floor W1 ... Communication area covered by first LCX W2 ... Communication covered by second LCX area

Claims (7)

A plurality of leaky coaxial cables laid in parallel with each other;
A plurality of access points connected to one end side or the other end side of each leaky coaxial cable,
Among the plurality of leaky coaxial cables, the access point is connected to one end side of one leaky coaxial cable adjacent to each other and the other end side of the other leaky coaxial cable,
The one leaky coaxial cable and the other leaky coaxial cable so as to cover at least a communication area between the one leaky coaxial cable and the other leaky coaxial cable; The distance between the other leaky coaxial cable is set ,
The plurality of leaky coaxial cables are laid in the height direction in a state of penetrating between the floors of the multi-storey building,
The access point connected to the one leaky coaxial cable and the access point connected to the other leaky coaxial cable are installed on the same floor,
The access point connected to the other leaky coaxial cable is connected to the other leaky coaxial cable via a connection cable,
The wireless communication system, wherein the other leaky coaxial cable and the connection cable are integrated to form a composite cable .   The one leaky coaxial cable and the other leak so that the boundary line of the communication area covered by the one leaky coaxial cable and the border line of the communication area covered by the other leaky coaxial cable are in contact with each other. The wireless communication system according to claim 1, wherein an interval between the coaxial cable and the coaxial cable is set. The wireless communication system according to claim 1 or 2 , wherein two or more leaky coaxial cables are connected to the access point via a distributor. Wireless communication system according to any one of claim 1 to 3, characterized in that a communication cable for electrically connecting between said plurality of access points and higher circuit. 5. The wireless communication system according to claim 4 , wherein two or more communication cables are connected to the upper line via a hub or a router. The wireless communication system according to claim 4 or 5 , wherein a composite cable in which the communication cable and the leaky coaxial cable are integrated is used. A plurality of leaky coaxial cables laid in parallel with each other;
A design method of a wireless communication system comprising a plurality of access points connected to one end side or the other end side of each leaky coaxial cable,
Among the plurality of leaky coaxial cables, one end side of one leaky coaxial cable adjacent to each other, and the other end side of the other leaky coaxial cable, respectively, the access point is connected,
The one leaky coaxial cable and the other leaky coaxial cable so as to cover at least a communication area between the one leaky coaxial cable and the other leaky coaxial cable; Set the distance between the other leaky coaxial cable ,
The plurality of leaky coaxial cables are laid in the height direction in a state of penetrating between the floors of the multi-storey building,
The access point connected to the one leaky coaxial cable and the access point connected to the other leaky coaxial cable are installed on the same floor,
The access point connected to the other leaky coaxial cable is connected to the other leaky coaxial cable via a connection cable,
The other leaky coaxial cable and the connection cable are integrated to form a composite cable .