WO2006096852A1

WO2006096852A1 - Wireless access point

Info

Publication number: WO2006096852A1
Application number: PCT/US2006/008696
Authority: WO
Inventors: Dirk Ion Gates; Kirk J. Matthews
Original assignee: Xirrus, Inc.
Priority date: 2005-03-09
Filing date: 2006-03-09
Publication date: 2006-09-14

Abstract

A wireless access point is provided for transmitting radio signals that has isolators positioned about the perimeter of the wireless access point dividing the perimeter of the wireless access point into segments and reflector plates positioned within each segment for directing the transmission of the radio signals within each segment.

Description

W

WIRELESS ACCESS POINT

CROSS REFERENCE TO RELATED APPLICATIONS

[001] This application is a continuation-in-part of US Design Patent Application Serial No. 29/217,531, titled "ELECTRONIC DEVICE HOUSING" filed November 17,

2004, which is incorporated herein by reference. This application claims priority to the provisional patent applications, serial number 60/660,171, titled "WIRELESS LAN ARRAY," by Dirk I, Gates, Ian Laity, Mick Conley, Mike de Ia Garrigue, and Steve Smith, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,276, titled "WIRELESS LAN ARRAY," by Dirk I. Gates, Ian Laity, Mick Conley, Mike de Ia Garrigue, and Steve Smith, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,375, titled "WIRELESS ACCESS POINT," by Dirk L Gates and Ian Laity, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,275, titled "MULTI-SECTOR WIRELESS ACCESS POINT ARRAY," by Dirk I. Gates Ian Laity, Mick Conley, Mike de Ia Garrigue, and Steve Smith, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,210, titled "MEDIA ACCESS CONTROLLER FOR USE IN A MULTI-SECTOR WIRELESS ACCESS POINT ARRAY," by Mike de Ia Garrigue and Drew Bertagna filed on March 9,

2005, and incorporated herein by reference; serial number 60/660,174, titled "QUEUE MANAGEMENT CONTROLLER FOR USE IN A MULTI-SECTOR WIRELESS ACCESS POINT ARRAY," by Mike de Ia Garrigue and Drew Bertagna filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,394, titled "WIRELESS LAN ARRAY," by Dirk I. Gates, Ian Laity, Mick Conley, Mike de Ia Garrigue, and Steve Smith, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,209, titled "WIRELESS LAN ARRAY ARCHITECTURE," by Dixk I. Gates, Ian Laity, Mick Conley, Mike de Ia Garrigue, and Steve Smith, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,393, titled "ANTENNA ARCHITECTURE OF A WIRELESS LAN ARRAY," by Abraham Hartenstein, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,269, titled "LOAD BALANCING IN A MULTI-RADIO WIRELESS LAN ARRAY BASED ON AGGREGATE MEAN LEVELS," by Mick Conley filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,392, titled "ADVANCED ADJACENT CHANNEL SECTOR MANAGEMENT FOR 802.11 TRAFFIC," by Mick Conley filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,391, titled "LOAD BALANCING IN A MULTI-RADIO WIRELESS LAN ARRAY BASED ON AGGREGATE MEAN LEVELS," by Shaun Clem filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,277, titled "SYSTEM FOR TRANSMITTING AND RECEIVING FRAMES IN A MULTI-RADIO WIRELESS LAN ARRAY," by Dirk I. Gates and Mike de Ia Garrigue, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,302, titled "SYSTEM FOR ALLOCATING CHANNELS IN A MULTI-RADIO WIRELESS LAN ARRAY," by Dirk I. Gates and Kirk Mathews, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,376, titled "SYSTEM FOR ALLOCATING CHANNELS IN A MULTI-RADIO WIRELESS LAN ARRAY," by Dirk I. Gates and Kirk Mathews, filed on March 9, 2005, and incorporated herein by reference; serial number 60/660,541, titled "MEDIA ACCESS CONTROLLER FOR USE IN A MULTI-SECTOR WIRELESS ACCESS POINT ARRAY," by Dirk I. Gates and Mike de Ia Garrigue, filed on March 9,

2005, and incorporated herein by reference; and PCT patent application, serial number PCT/US2006/008747, titled "WIRELESS LOCAL AREA NETWORK ANTENNA ARRAY," filed on March 9, 2006, which claims priority to the above provisional patent applications, and incorporated by reference herein; PCT patent application serial number PCT/US2006/008744, titled "MEDIA ACCESS CONTROLLER FOR USE IN A MULTI- SECTOR WIRELESS ACCESS POINT ARRAY," filed on March 9, 2006, and incorporated by reference herein; PCT patent application serial number PCT/US2006/008743, titled "ACCESS POINT IN A WIRELESS LAN," filed on March 9,

2006, and incorporated by reference herein; PCT patent application serial number PCT/US2006/008698, titled "SYSTEM FOR ALLOCATING CHANNELS IN A MULTI- RADIO WIRELESS LAN ARRAY," filed on March 9, 2006, and incorporated by reference herein. BACKGROUND OF THE INVENTION [002] 1. Field of the Invention

[003] This invention relates generally to wireless access points. In particular, this invention relates to a wireless access for increasing the coverage area of a single wireless access point using a multi-sector antenna system. [004] 2. Related Art

[0010] Currently available wireless access points are often time deficient in coverage area, range and capacity. To provide access for large or obstructed areas, and to provide additional capacity for data intensive networks, multiple wireless access point devices and switches need to be deployed and used simultaneously. Deploying multiple wireless access points in a given area only provides incremental improvements in capacity due to the channel reuse and co-channel interference problems that arise from placing multiple wireless access points in close proximity to each other. Current architectures are not capable of maximizing capacity because they lack the ability to allow densely deployed wireless access points to operate together and isolate RF bleed-over of transmissions between cells on the same channel, which is a fundamental problem with allowing multiple wireless access points to function at very close proximity to each other. [0011] A need therefore exists for a wireless access point, such as wireless access point for use in a local area network, i.e., a wireless LAN array, that overcomes some of the shortcomings of currently available wireless access points by providing an wireless access point with increased network capacity and increased coverage in all directions. [0012] In particular, a need exists for a wireless access point that allows for the co- location of antennas, radios and switches and that minimizes electromagnetic crosstalk and interference issues resulting from the co-location of multiple antennas, radios and switches. SUMMARY

[0013] A wireless access point is provided that minimizes electromagnetic crosstalk, interference and co-location issues between neighboring radios and antennas, which by their implementation, enable a multitude of radios and antennas to be deployed within a single device. In particular, a wireless access point with a multitude of radios is provided for transmitting radio signals having a digitally isolated, high-gain, multi-sector antenna system positioned about the perimeter of the wireless access point. The wireless access point further includes both reflective surfaces and absorptive isolators positioned within each antenna sector for the purpose of directing the transmission of the radio signals within each segment and enabling radio co-existence.

[005] In one example of one implementation of the wireless access point, the wireless access point integrates a WLAN switch and up to sixteen 802.11 Wi-Fi wireless access points and associated antennas into a single device.

[006] Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE FIGURES

[007] The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. [008] Figure 1 is a top perspective view of one example of an implementation of the wireless access point.

[009] Figure 2 is a bottom perspective view of the wireless access point of Figure 1. [010] Figure 3 is a top view of the wireless access point of Figure 1. [011] Figure 4 is a side view of the wireless access point of Figure 1. [012] Figure 5 is a top plan view of the wireless access point of Figure 1 with the exterior portion of the top cover removed.

[013] Figure 6 is a top perspective view of the wireless access point of Figure 5 illustrating several of the antenna sections.

[014] Figure 7 is a bottom perspective view of the wireless access point of Figure 1 illustrating several of the antenna sections as they would appear with the bottom plate removed.

[015] Figure 8 is a top perspective view of the wireless access point of Figure 7. [016] Figure 9 is a perspective view of the bottom portion of the wireless access point of Figure 1 with the securing portion of the wireless access point removed. [017] Figure 10 is an exploded perspective top view of the wireless access point of Figure 1.

[018] Figure 11 is an exploded perspective bottom view of the wireless access point of Figure 1.

[019] Figure 12 is top view of another example of an implementation of the wireless access point.

[020] Figure 13 illustrates a plan view of the 802.11a coverage area that may be achieved by the wireless access point of Figure 1.

[021] Figure 14 illustrates a plan view of the 802.11b/g coverage area that may be achieved by the wireless access point of Figure 1. [022] Figure 15 illustrates a plan view of the area of listening coverage that may be DETAILED DESCRIPTION

[023] Figure 1 is a top perspective view of one example of an implementation of a wireless access point 100. The wireless access point 100 consists generally of an array portion 102 and a securing portion 104. As illustrated, the wireless access point 100 may be generally circular in shape or other shape, such as an ellipsis or a polygon, e.g., a pentagon, octagon, hexagon, etc., capable of transmitting signals in all directions. In particular, the wireless access point 100 may be designed to transmit signals 360 degrees outwardly from the center of the wireless access point 100, as illustrated in Figure 3 (see below), and 180 degrees outward from the array portion 102 relative to the securing portion 104, as illustrated in Figure 4 (see below).

[024] The wireless access point 100 may be positioned at a point elevated above the desired coverage area, such as the ceiling or mounted on a pole. In this case, transmissions would be directed downward and outward from the wireless access point 100, as illustrated in Figure 4 (see below). Alternatively, the wireless access point 100 could be inverted and placed at a position either below or within the coverage area, such as on the floor or on a table. In this manner, the coverage would be directed upward and outward, rather than downward and outward, as illustrated in Figure 4. For purposes of this application, the top of the wireless access point 100 shall be the side of the wireless access point 100 that is positioned toward the coverage zone, regardless of whether the wireless access point 100 is facing upward or downward. The bottom of the wireless access point 100 shall be the side of the wireless access point 100 that is positioned away from the coverage zone, or the side of the wireless access point 100 having the securing portion 104.

[025] Accordingly, the securing portion 104 of the wireless access point 100 may positioned either upward or downward depending upon whether the wireless access point 100 is positioned above, below or within the desired coverage area. Similarly, despite the terminology used in this application, the array portion 102 of the wireless access point 100 may represent the bottom portion of the wireless access point 100 when positioned at a point elevated above the coverage area or the top portion of the wireless access point 100 when positioned within or below the desired coverage area. The wireless access point 100 may be powered by batteries, through an AJC power outlet or remotely through a D/C power supply.

[023] Figure 2 is a bottom perspective view of the wireless access point 100 of Figure 1. As illustrated in figure 2, the securing portion 104 if the wireless access point 100 may include holes 202 positioned at predetermined locations for securing the wireless access point 100 to different types of surfaces, such as drop ceiling brackets, in which case holes 202 may align with the positioning of the ceiling brackets. The securing portion 104 of the wireless access point may be secured first and then the array portion 102 is to be fastened to the securing portion 104 to assemble the wireless access point 100. [024] Figure 3 is a top view of the wireless access point 100 of Figure 1. As illustrated, the top view of the wireless access point 100 includes the array portion 102. As explained further below, it through the array portion 102 of the wireless access point 100 that the signal is transmitted 360 degrees from the circumference of the array portion 102 and 180 degrees outward from the array portion 102 relative to the securing portion 104, as illustrated in Figure 4.

[025] Figure 4 is a side view of the wireless access point of Figure 1. As illustrated in Figure 4, the securing portion 104 of the wireless access point 100 is secured to a mounting element 402, such as a drop ceiling bracket. As further illustrated, the wireless access point 100 transmits signals 180 degrees outward from the array portion 102 relative to the securing portion 104 and/or mounting element 402. As further seen in Figure 4, the array portion 102 includes a top cover 404 and a bottom cover 406. The top cover 404 of the array portion 102 includes an interior portion 408 and an exterior portion 410. [026] Figure 5 is a top plan view of the wireless access point 100 of Figure 1 with the exterior portion 410 of the top cover 404 removed, showing only the remaining interior portion 408 of the top cover 404. As illustrated, the perimeter of the wireless access point 100 is divided into antenna sectors 502. Figure 5 illustrates the primary components of each antenna sector 520 and the implementation of a 16 integrated wireless access points, which in this example is twelve (12) 802.11a and four (4) 802.1 la/b/g and the supportive 12 antenna sector 502 array. While in this example, the wireless access point 100 includes twelve antenna sectors 502 defined around the perimeter of the wireless access point 100, to twelve, may be defined in the wireless access point 100. The wireless access point 100 may be divided into multiple sectors 502 as necessary to achieve the desired coverage and network capacity. Further, while the example utilizes 802.11a and 802.11 a/b/g channels, all approved 802.11 channels may utilized in connection with the wireless access point, including both currently approval and future approved frequencies and channels. [027] As illustrated in Figure 5, the antenna sectors 502 are positioned in and around the circumference of the wireless access point 100 and are separated from the interior of the wireless access point 100, i.e., the central digital section 510, by a circular antenna reflector 504. In this example, the antenna sectors 502 are positioned in a circular pattern around the perimeter of the array section 102 of the wireless access point 100. Absorptive isolators 506 separate each antenna sector 502 at its sides, such that each antenna sector 502 includes two (2) absorptive isolators 506. The absorptive isolators 506 enhance the isolation from antenna sector 502 to antenna sector 502. These isolators 506 may be foam isolators of the type generally known in the industry and commercially available for the purpose of isolating radio transmission or may be any other isolator capable of absorbing electromagnetic energy. For example, the isolators 506 may be foam-filled graphite- isolated insulators to prevent interference between antenna sectors 502. [028] As illustrated, the isolators 506 form antenna sectors 502 about the perimeter of the wireless access point. The purpose of the isolators 506 is to isolate the antenna or antennas positioned within each antenna sector 502.

[029] Figure 5 also illustrates the inclusion of antenna sector deflectors 508 at the base of each antenna sector 502. The antenna deflectors 508 deflect the radio signals downward or away from the wireless access point in a 180 degree pattern relative to the mounting element or securing portion 104, as shown in Fig 4. When inverted, for example, on a table top, the antenna deflectors 508 will reflect the radio signal upward. On the other hand, the circular antenna reflector 504 reflects the radio signal outward in a 360 degree pattern, as shown in Figure 3. Both the antenna reflector 504 and antenna deflectors 508 can be constructed from most metallic or metallically coated materials, or any other material capable of directing radio signals. Both the antenna reflector 504 and the antenna deflector 508 can be referred to as reflector plates. Although the example elements, the antenna reflectors 504 and antenna deflectors 508 can be constructed from a single piece and together form a single reflector plate.

[030] Although Figure 5 illustrates the antenna reflector 504 designed as a circular ring positioned about an interior perimeter of the wireless access point, individual antenna reflectors 504 may be positioned in each antenna section 502. Likewise, the antenna deflectors 508 may be constructed such that the deflectors 508 extend in a circular manner across the base of each section 502, similar to the way the antenna reflector 504 illustrated in Figure 5 is a continuous ring creating a backdrop for the antenna sectors 502. [031] Figure 6 is a top perspective view of the wireless access point 100 of Figure 5 further illustrating several of the antenna sections 502. As illustrated, the circular antenna reflector 504 serves both to reflect radio signals outward from the wireless access point 100 and to provide an isolation barrier between the central digital section 510 (Fig. 5) and the antenna sectors 502. As further illustrated in Figure 6, the antennas 602 positioned within each antenna sector 502 are positioned central relative to the antenna deflectors 508, reflector 504 and absorptive isolators 504. As illustrated, the antennas 602 are connected to radio printed circuit board assemblies ("PCBA") 604.

[032] Figure 7 is a bottom perspective view of the wireless access point of Figure 1 illustrating several of the antenna sections as they would appear with the bottom plate removed. Similarly, Figure 8 is a top perspective view of the wireless access point 100 of Figure 7. Figure 7 and 8 illustrate that the antenna reflector 504 and antenna deflector 508 are grounded together 702, and that both the antenna reflector 504 and antenna deflector 508 are tied to a system ground via the circular antenna reflector 504 connection to the ground plane of the radio PCBA 604. Further, Figure 8 shows one method, spring fingers, of connecting a metallic antenna reflector 504 to the antenna deflector 508. Figure 8 also illustrates one implementation of the antenna deflector 508, a radio PCBA substrate with tin plated deflective patterns positioned directly below the antenna substrate. Those skilled in the art will recognize that other knows means may be utilized for connecting and grounding the structure.

[033] Figure 9 is a perspective view of the array portion 102 of the wireless access point 100 of Figure 1 with the securing portion 104 removed. As further illustrated in as a housing for the wireless access point 100. In this example, the array portion 102 is an injection molded plastic housing that can be made of one or more part. Those skilled in the art will recognize that other materials may be utilized to create the array portion 102 or housing for the wireless access point 100.

[034] Figure 10 is an exploded perspective top view of the wireless access point 100 of Figure 1 and Figure 11 is an exploded perspective bottom view of the wireless access point of Figure 1. As illustrated in Figure 10, the wireless access point 100 may be divided into multiple antenna sectors 502 as necessary to achieve the desired coverage area. While the isolators 506 are shown positioned within the bottom cover 406 of the array portion 102 of the wireless access point 100, the isolators they may also be secured in the top cover 404 of the array portion 102. As illustrated in Figure 11, the radio PCBA 604 may be positioned within the top cover 404 of the array portion 102. Alternatively, the radio PCBA 604 may be positioned within the bottom cover 406 of the array portion 102. [035] Figure 12 is top view of another example of an implementation of a wireless access point 900 having multiple antenna sectors 902. Figure 12 illustrates and an alternative construction of the antenna reflector 904, antenna deflector 908, isolating elements 906 and grounding elements 912. The EMI suppression required in the central digital sector 910, the antenna reflector 904, antenna deflector 908, and system ground connections 912 between these elements may be designed from a single contiguous metallic surface, as illustrated or from separate elements. In the example illustrated in Figure 12, the digital sector 910, antenna reflector 904, and antenna deflector 908 are contracted from a single thermoformed plastic liner that has been electroplated with a metallic substrate and are hence inherently grounded to each other. Alternatively, these elements may be constructed from different substrates.

[036] Figure 13 illustrates a plan view of the 802.11a coverage area that may be achieved by the wireless access point 100 of Figure 1 over a given area 1300. Figure 14 illustrates a plan view of the 802.1 lb/g coverage area that may be achieved by the wireless access point 100 of Figure 1 over a given area 1300. Figure 15 illustrates a plan view of the area of listening coverage that may be achieved by the wireless access point 100 of Figure 1 over a given area 1300. [037] While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention.

Claims

CLAIMS What is claimed is:

1. A wireless access point for transmitting radio signals, the wireless access point comprising: isolators positioned about the perimeter of the wireless access point dividing the perimeter of the wireless access point into segments, and a reflector plate positioned within each segment for directing the transmission of the radio signals within each segment.

2. The wireless access point of claim 1 where the isolators are foam.

3. The wireless access point of claim 1 where the reflector plates include a ground plate.

4. The wireless access point of claim 1 where the reflector plates include a deflective ring.

5. The wireless access point of claim 1 where the reflector plates include both a deflective ring and a ground plate.

6. The wireless access point of claim 1 where the wireless access point is generally circular in shape.

7. The wireless access point of claim 1 where the wireless access point is generally elliptical in shape.

8. A wireless access point for transmitting radio signals, the wireless access point comprising: a plurality of antenna sectors ; absorotive isolators inP.atfiH hfitwppn pnrh ant^pram oof-tnr^> a reflective surface within each antenna sector for directing the transmission of radio signals within each antenna sector; and a deflective surface within each antenna sector for directing the transmission of radio signals within each antenna sector.

9. The wireless access point of claim 8 where the wireless access point further includes a digital section and the deflective surface acts as an isolation barrier between the central digital section and the antenna sectors.

10. The wireless access point of claim 8 where the antenna sectors are arrayed in a generally circular pattern and are capable of transmitting signals outwardly 360 degrees from the center of the wireless access point.

11. The wireless access point of claim 8 where the antenna sectors are arrayed in a generally circular pattern and are capable of transmitting signals 180 degrees upward from the wireless access point.

12. The wireless access point of claim 8 where the absorptive isolators are foam.

13. The wireless access point of claim 8 where the reflector surface includes a ground plate.

14. The wireless access point of claim 8 where the deflector surface includes a ground plate.

15. The wireless access point of claim 8 where the reflector surface includes a reflective ring.

16. The wireless access point of claim 8 where the reflector surface includes a both a reflective rin P and a ornπnH niatp

17. The wireless access point of claim 8 where the wireless LAN array is generally round in shape.

18. The wireless access point of claim 8 where the wireless LAN array is generally elliptical in shape.

19. The wireless access point of claim 8 where wireless access point further includes a digital suppression element and where the digital suppression element, antenna reflective surface and antenna deflector surface are made from one contiguous piece of conductive and reflective material and are inherently grounded together.