Abstract:
A system is provided comprising a single wireless cell configured to operate in a packet-switched cellular network, the single wireless cell including: a first transmission point with a multiple-input-multiple-output (MIMO) capability; a second transmission point with a MIMO capability; and third circuitry in communication with first circuitry of the first transmission point and second circuitry of the second transmission point. The single wireless cell is configured such that the first transmission point cooperates with the second transmission point in connection with a first transmission to a MIMO-capable portable wireless device, for improving the first transmission. The single wireless cell is further configured for: receiving first information from the first MIMO-capable portable wireless device; receiving second information from the first MIMO-capable portable wireless device; altering at least one aspect of the first transmission; and transmitting data in connection with the first transmission to the first MIMO-capable portable wireless device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of and claims priority under 35 U.S.C. Section 120 from U.S. patent application Ser. No. 14/476,628 by Lastinger filed Sep. 3, 2014, which is a continuation of U.S. patent application Ser. No. 13/348,523 by Lastinger filed Jan. 11, 2012, now U.S. Pat. No. 8,855,089 which is a continuation of U.S. patent application Ser. No. 13/118,386 by Lastinger filed May 28, 2011, now U.S. Pat. No. 8,345,651 which is a continuation of U.S. patent application Ser. No. 11/709,431 by Lastinger filed Feb. 21, 2007, now U.S. Pat. No. 8,009,646, which claims priority under 35 U.S.C. sctn. 119(e) from U.S. Provisional Patent Application Ser. No. 60/743,376 filed Feb. 28, 2006, each of the aforementioned applications is herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention relate to wireless communication using Multiple Input Multiple Output (“MIMO”) antennas and methods of operation. 
       BACKGROUND OF THE INVENTION 
       [0003]    Wireless devices find uses in a variety of applications for example, providing communication between computers, wireless cells, clients, hand-held devices, mobile devices, and file servers. Wireless devices with Multiple Input Multiple Output (“MIMO”) antennas benefit from spatial diversity and redundant signals. Noise sources may interfere with wireless devices that use MIMO antennas. Wireless communication using devices having MIMO antennas may substantially benefit from selecting a MIMO physical sector and/or a MIMO virtual sector to improve performance. 
       SUMMARY OF THE INVENTION 
       [0004]    A system is provided comprising a single wireless cell configured to operate in a packet-switched cellular network, the single wireless cell including: a first transmission point with a multiple-input-multiple-output (MIMO) capability; a second transmission point with a MIMO capability; and third circuitry in communication with first circuitry of the first transmission point and second circuitry of the second transmission point. The single wireless cell is configured such that the first transmission point cooperates with the second transmission point in connection with a first transmission to a MIMO-capable portable wireless device, for improving the first transmission. The single wireless cell is further configured for: receiving first information from the first MIMO-capable portable wireless device; receiving second information from the first MIMO-capable portable wireless device; altering at least one aspect of the first transmission; and transmitting data in connection with the first transmission to the first MIMO-capable portable wireless device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0005]    Embodiments of the present invention will now be further described with reference to the drawing, wherein like designations denote like elements, and: 
           [0006]      FIG. 1  is a diagram of an exemplary wireless device according to the various aspects of the present invention; 
           [0007]      FIG. 2  is a diagram of exemplary physical sectors; 
           [0008]      FIG. 3  is a diagram of exemplary physical sectors that form exemplary MIMO physical sectors; 
           [0009]      FIG. 4  is a diagram of exemplary MIMO virtual sectors; 
           [0010]      FIG. 5  is a diagram of an exemplary MIMO virtual sector; 
           [0011]      FIG. 6  is a diagram of exemplary MIMO virtual sectors; 
           [0012]      FIG. 7  is a diagram of exemplary alternate method for diagrammatically indicating physical sectors, MIMO physical sectors, and MIMO virtual sectors; 
           [0013]      FIG. 8  is a diagram of communication between exemplary wireless devices in the presence of noise sources; 
           [0014]      FIG. 9  is a diagram of an exemplary wireless device having three radios and three antennas for each radio; 
           [0015]      FIG. 10  is a diagram of exemplary physical sectors that form exemplary MIMO physical sectors; 
           [0016]      FIG. 11  is a diagram of an exemplary wireless device having two radio groups, each group having two radios and two antennas for each radio; 
           [0017]      FIG. 12  is a diagram of exemplary physical sectors that substantially overlap to form exemplary MIMO physical sectors; 
           [0018]      FIG. 13  is a diagram of exemplary physical sectors that partial overlap to form exemplary MIMO virtual sectors; 
           [0019]      FIG. 14  is a diagram of exemplary physical sectors that partial overlap to form exemplary MIMO virtual sectors; 
           [0020]      FIG. 15  is a diagram of exemplary physical sectors that partial overlap to form exemplary MIMO virtual sectors; 
           [0021]      FIG. 16  is a diagram of exemplary physical sectors that substantially overlap to form exemplary MIMO physical sectors and exemplary MIMO physical sectors that partially overlap to form exemplary MIMO physical sectors; 
           [0022]      FIG. 17  is a diagram of communication between exemplary wireless devices in the presence of noise sources; 
           [0023]      FIG. 18  is a diagram of communication between exemplary wireless devices in the presence of exemplary noise sources; 
           [0024]      FIG. 19  is a diagram of a method for forming MIMO physical sectors; and 
           [0025]      FIG. 20  is a diagram of a method for forming MIMO physical sectors. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Wireless devices use antennas to transmit and receive radio signals. Noise sources, such as other wireless devices including wireless devices that transmit on the same channel, may interfere with wireless communication. Conventional wireless devices use a variety of techniques to reduce the detrimental effect of noise on communication for example, dividing the area of coverage into sectors, using directional antenna, and using multiple antennas to provide redundancy and spatial diversity. 
         [0027]    An improved wireless device, according to the various aspects of the present invention includes directional antennas positioned in such a way that the physical sectors of the antennas of the wireless device overlap and the antennas selected for communication are the antennas whose physical sectors overlap in an area in a manner that permits the antennas to operate as a Multiple Input Multiple Output (“MIMO”) antenna. 
         [0028]    The wireless device, according to the various aspects of the present invention may select for communication any suitable combination of directional antennas that operate as a MIMO antenna and are oriented in a desired direction of communication. Furthermore, the wireless device may assign any available channel to the antennas to improve performance. 
         [0029]    A wireless device, according to the various aspects of the present invention includes, for example, wireless cells, access points, wireless clients, mobile computers, and handheld devices. 
         [0030]    The term “physical sector” is understood to mean the area of coverage in which an antenna transmits and receives signals. The size and shape of a physical sector depends on a variety of factors for example, the type of antenna, atmospheric conditions, presence of noise sources, and physical surroundings. Physical sectors  58 ,  60  and  62  represent the two-dimensional shape of idealized physical sectors of directional antennas. Physical sectors  58 ,  60  and  62  do not overlap in  FIG. 2 . Physical sectors  58 ,  60  and  62  substantially overlap in  FIG. 3 . Physical sectors  58 ,  60  and  62  partially overlap in  FIGS. 4 and 5 . 
         [0031]    The term “MIMO antenna” is understood to mean at least two antennas that each transmits and/or receives signals on the same channel in the area where the physical sectors of the antennas overlap. Antennas may be positioned in such a way that their physical sectors overlap. Antennas whose physical sectors overlap in the same area may be configured to operate as a MIMO antenna in that area. Each individual antenna of a MIMO antenna operates on the same channel (e.g., frequency, encoding, or other method of dividing the radio spectrum for communication). A MIMO antenna provides, inter alia, spatial diversity between the antennas, redundancy, and temporal diversity to reduce the effects of noise on transmission and reception. Reducing the effects of noise permits a wireless device to communicate more reliability. 
         [0032]    Antennas that form a MIMO antenna may be oriented to use different signal polarization for example, horizontal, vertical, and circular. Antennas that form a MIMO antenna may be physically separated to provide spatial diversity. 
         [0033]    MIMO physical sectors are formed to provide communication with increased immunity to noise within the area of the MIMO physical sector. The term “MIMO physical sector” means the area where the physical sectors of the antennas that operate as a MIMO antenna overlap. 
         [0034]    In an exemplary embodiment, referring to  FIG. 3 , physical sectors  58 ,  60 , and  62  substantially overlap to form MIMO physical sector  82 . Physical sectors  66 ,  68 , and  70  substantially overlap to form a MIMO physical sector  84 . In this embodiment, each MIMO physical sector has an angle of coverage of about 90 degrees. In another embodiment, referring to  FIG. 6 , each one physical sector  58 ,  60 , and  62  and each one physical sector  66 ,  68 , and  70  has an angle of coverage of about 180 degrees, thus the resulting MIMO physical sectors  82  and  84  have an angle of coverage of about 180 degrees.  FIG. 7  represents an alternate method for diagrammatically representing physical sectors and MIMO physical sectors. Physical sectors  58 - 62  respectively have about a 180 degree angle of coverage and the center of each physical sector is oriented at approximately 90 degrees (straight up on the page). Each physical sector  58 - 62  extends from wireless device  10  to the furthest extent reached by the respective antennas even though  FIG. 7  shows gaps between the physical sectors for clarity. The MIMO physical sectors  82  and  84  of  FIGS. 6 and 7  are equivalent; however, the diagrammatical representation of  FIG. 7  provides greater clarity. Thus, MIMO physical sectors  82  and  84  respectively include three substantially overlapping physical sectors  58 - 62  and  66 - 70 . 
         [0035]    The physical sectors of the antennas that form a MIMO antenna are not limited to being substantially overlapping. When physical sectors only partially overlap, the MIMO physical sector is the area where the physical sectors of the antennas that form the MIMO antenna overlap. Referring to  FIGS. 4 and 5 , the antennas associated with physical sectors  58 - 62  transmit and receive using the same channel. Area  94  is the area where physical sectors  58 ,  60 , and  62  overlap, thus area  94  is a MIMO physical sector. The antennas associated with physical sectors  58 - 62  operate as a MIMO antenna in area  94 . The MIMO physical sector formed by physical sectors  66 - 70  is also shown in  FIG. 4  as MIMO physical sector  82 . 
         [0036]    MIMO physical sectors may be formed in a variety of ways. In one exemplary method for forming a MIMO physical sector, referring to  FIG. 19 , antennas are selected to operate as a MIMO antenna then the antennas are positioned in such a way that the physical sectors of the antennas overlap. In another exemplary method for forming a MIMO physical sector, referring to  FIG. 20 , a plurality of antennas are positioned in such a way that the physical sectors of at least some of the antennas at least partially overlap then at least two antennas are selected to operate as a MIMO antenna in the area where their physical sectors overlap to form a MIMO physical sector. The plurality of antennas may be positioned in such a way that the various MIMO physical sectors that are formed are oriented in different directions. At least two antennas may be selected to operate as a MIMO antenna in accordance with the orientation of the MIMO physical sector formed by the physical sectors of the selected antennas. The orientation of some MIMO physical sectors may provide increased performance over the orientation of other MIMO physical sectors. Furthermore, the antennas that form the MIMO antenna may be assigned any available channel. Accordingly, the selected antennas, thus the MIMO physical sector, may be assigned to a channel that provides improved performance. 
         [0037]    The term “MIMO virtual sector” means the area where the physical sectors of antennas that may operate as a MIMO antenna overlap. Referring to  FIG. 13 , physical sectors  58 - 62  and  66 - 70  each have an angle of coverage of about 180 degrees respectively. The antennas associated with physical sectors  58 - 62  and  66 - 70  are positioned in such a way that in area  150 , physical sectors  58 ,  68 , and  70  overlap. In area  152 , physical sectors  58 ,  60 , and  70  overlap and so forth for areas  154 - 160 . Each one area  150 - 160  comprises a MIMO virtual sector because the antennas whose physical sectors overlap in the area may operate as a MIMO antenna. If the antennas associated with physical sectors  58 ,  68 , and  70  are selected to form a MIMO antenna, then area  150  operates as a MIMO physical sector. If the antennas associated with physical sectors  58 ,  60 , and  70  are selected to form a MIMO antenna, then area  152  operates as a MIMO physical sector and so forth for the other areas. Before antennas are selected to form a MIMO physical sector, areas  150 - 160  are MIMO virtual sectors. When antennas are selected to form a MIMO antenna, the area where the physical sectors of the selected antennas overlap become a MIMO physical sector while the other areas remain MIMO virtual sectors. A MIMO physical sector may also be referred to as a selected MIMO virtual sector or an active MIMO virtual sector. Any criteria may be used to select a MIMO virtual sector for communication. 
         [0038]    The method of positioning antennas to form MIMO virtual sectors then selecting antennas to operate as a MIMO antenna permits the wireless device to respond to changes in, inter alia, performance, noise sources, and the environment by communicating through the MIMO physical sector that provides increased performance. 
         [0039]    Positioning antennas to form MIMO virtual sectors permits a wireless device with fixed antenna positions to select from a variety of MIMO virtual sectors to communicate using the MIMO physical sector that provides a desired level of performance. When the performance of the selected MIMO physical sector deteriorates due to, inter alia, noise sources or environmental conditions, the wireless device can select different antennas to operate as a MIMO antenna, thereby selecting a different MIMO virtual sector to operate as a MIMO physical sector where the different MIMO physical sector provides increased performance. 
         [0040]    MIMO physical sectors permits a wireless device to communicate with increased performance. MIMO virtual sectors permits a wireless device to select an area to transmit and receive in accordance with the MIMO virtual sector that provides a desired level of performance. A wireless device having multiple MIMO virtual sectors may select between the various MIMO virtual sectors. A wireless device may select the MIMO virtual sector that provides an increased level of performance. Positioning the antennas of a wireless device to form MIMO virtual sectors that are oriented in different directions permits the wireless device to select a MIMO physical sector based on the orientation of the virtual sector with relation to the position of noise sources. 
         [0041]    Performance may be measure by, inter alia, throughput, data throughput, signal-to-noise ratio, reduced signal error, reduced data errors, reduced retransmission requests, reduced interference, rejection of multipath signals, higher transmission rates, and signal strength. 
         [0042]    A MIMO system includes radios and antennas that may be configured to form MIMO antennas, MIMO physical sectors, and MIMO virtual sectors. A MIMO system may form a MIMO antenna using any suitable combination of radios and antennas. A MIMO system may select any suitable MIMO physical sector for communication. A MIMO system may have any suitable number of MIMO virtual sectors and/or selected MIMO virtual sectors. The MIMO system may position its MIMO physical sectors at any orientation. The MIMO physical sectors of a MIMO system may overlap other MIMO physical sectors of the same MIMO system. Overlapping MIMO physical sectors of the same MIMO system may be assigned different channels. 
         [0043]    A MIMO system has at least two radios and at least two antennas where at least two radios and two antennas form a MIMO antenna. In another exemplary embodiment, referring to  FIG. 1 , a MIMO system has three radios with two antennas interfacing with each one radio. Three antennas, one antenna from each radio, may operate as a MIMO antenna, thereby resulting in a MIMO system having two MIMO antennas. 
         [0044]    The present invention may employ various types of radios using any type of communication protocol and operating at any frequency and/or with any number of channels suitable for the application. The present invention may use any variety of antennas or groups of antennas for any purpose for example, transmission, reception, noise reduction, and multipath detection. Antennas may be positioned in any manner for example, their physical sectors may be overlapping and non-overlapping. Radios and antennas may operate as a MIMO system, MIMO antennas, MIMO physical sectors, and MIMO virtual sectors. Any type of algorithm and/or processor may be used to enable radios and/or antennas to form and operate as MIMO antennas. Antennas may be selected for communication according to any criteria such as for example, data throughput, signal strength, signal quality, and signal-to-noise ratio. 
         [0045]    In one embodiment, the antennas of the wireless device are positioned to form non-overlapping MIMO physical sectors and one of the non-overlapping MIMO physical sectors is selected for communication with other wireless devices. In another embodiment, the antennas of the wireless device are positioned to form overlapping MIMO virtual sectors and some of the MIMO virtual sectors are selected for communication with other wireless devices. 
         [0046]    The antennas that form a MIMO antenna may be used in any manner to transmit and/or receive signals for example, any number of antennas that operate as the MIMO antenna may transmit only, receive only, and transmit and receive signals. 
         [0047]    In an exemplary embodiment, referring to  FIG. 1 , antennas  34 ,  36 , and  38 , with their associated radios, form a MIMO antenna in which each antenna  34 ,  36 , and  38  transmits and receives the same signals. In another embodiment, antennas  34 - 38  form a MIMO antenna in which antenna  34  transmits, antenna  36  receives only, and antenna  38  transmits and receives. Different MIMO antenna configurations may provide different communication characteristics. For example, a configuration where all antennas of the MIMO antenna transmit and receive the same information may provide increased error correction. A configuration where antennas transmit and/or receive different information may provide increased data throughput. In an configuration where each antenna of the MIMO antenna receives some version of the same signal, the information content of the various signal versions received by the antennas of the MIMO antenna may be highly similar and/or less similar depending on environmental conditions for example, the presence of noise sources, multipath reflections, and spatial diversity of the antennas. Advanced algorithms may be used to process the signal received by each antenna that form the MIMO antenna to construct a resultant receive signal that contains as much of the receive signal information as can be extracted. The antennas of a MIMO antenna may be configured to receive signals from a common source by positioning the antennas such that their physical sectors overlap. 
         [0048]    The number of antennas used to form a MIMO physical sector and the overlap of the physical sectors of the antennas may affect performance. For example, referring to  FIGS. 1 and 5 , area  90  receives coverage from only physical sector  62 , thus communications within area  90  are transmitted and received by only antenna  38 . Likewise, area  98  receives coverage only from physical sector  60  and antenna  36 . Even when antennas  36  and  38  are selected to operate as a MIMO antennas, areas  90  and  98  are not MIMO physical sectors because only one antenna operates in the area. When only one antenna of the antennas selected to operate as a MIMO antenna transmits and receives in an area, the performance may not be as high as in the areas where the physical sectors of the antennas overlap to form a MIMO physical sector. Areas  92  and  96  receive coverage from physical sectors  58 ,  62  and  58 ,  60  respectively. Areas  92  and  96  are MIMO physical sectors because at least two antennas operate as a MIMO antenna in the areas. Communication using at least two antennas of the antennas selected to operate as a MIMO antenna may improve performance. Area  94 , a MIMO physical sector formed by the overlap of the physical sectors of three antennas, receives coverage from physical sectors  58 ,  60  and  62  and their related antennas  34 - 38 . Antennas  34 - 38  operate as a MIMO antenna, thus reception and/or transmission through all three antennas in area  94  may provide higher performance than reception and/or transmission through areas  90 - 92  and  96 - 98 . The MIMO physical sector in area  94  is most likely to provide improved performance because all antennas of the MIMO antenna communicate in area  94 . 
         [0049]    MIMO physical sectors formed using directional antennas may use conventional antenna select methods to reduce interference from noise sources. For example, referring to  FIGS. 1 and 8 , wireless device  10  comprises processor  12 , radios  18 - 22 , RF switches  26 - 30 , and antennas  34 - 38  and  42 - 46  where two antennas interfacing with each one RF switch respectively. Antennas  34 - 38  and  42 - 46  operate as a first MIMO antenna and a second MIMO antenna respectively. Radios  18 - 22  use the 802.11a/b/g/n communication protocols. Antenna physical sectors  58 - 62 , associated with antennas  34 - 38  respectively, substantially overlap to form MIMO physical sector  82 . Antenna physical sectors  66 - 70 , associated with antennas  42 - 46  respectively, substantially overlap to form MIMO physical sector  84 . In this embodiment, each radio is set to the same channel. The physical sectors and the MIMO physical sectors  82 - 84  extend farther than shown in  FIG. 8  to enable wireless device  10  to communicate with wireless device  102  and receive interference from noise sources  106  and  108 . Wireless device  10  uses RF switches  26 - 30  to select between antennas  34 - 38  and  42 - 46 . In this embodiment, the RF switches select between one of two groups of antennas; either antennas  34 - 38  or antennas  42 - 46  are selected, thus only one MIMO physical sector, either  82  or  84 , is active at any given time. In the embodiment and the scenario described in  FIG. 8 , wireless device  10  selects MIMO antennas physical sector  84  to reduce interference from noise sources  106  and  108  while communicating with wireless device  102 . Wireless device  104  of  FIG. 8  may also be implemented using MIMO physical sectors similar to those of wireless device  10 . Wireless device  104  may select the MIMO physical sector that provides the best performance while communicating with wireless device  102  and reduces interference from noise source  110 . 
         [0050]    In another embodiment of a MIMO system, referring to  FIG. 9 , wireless device  10  comprises a processor  12 , three radios  18 - 22 , three RF switches  26 - 30 , and three antennas interfacing with each RF switch. Antennas  34 - 38 ,  42 - 46 , and  50 - 54  may have any angle of coverage, be oriented in any direction, form MIMO antennas, and form MIMO virtual sectors in any manner. In an exemplary embodiment, referring to  FIG. 10 , each antenna  34 - 38 ,  42 - 46 , and  50 - 54  has an angle of coverage of about 120 degrees. Antennas  34 - 38  are oriented so that their associated physical sectors,  58 - 62  respectively, substantially overlap to form MIMO physical sector  82 . Antennas  42 - 46  are oriented so that their associated physical sectors,  66 - 70  respectively, substantially overlap to form MIMO physical sector  84 . Antennas  50 - 54  are oriented so that their associated physical sectors,  74 - 78  respectively, substantially overlap to form MIMO physical sector  86 . Physical sectors  58 - 62 ,  66 - 70 , and  74 - 78  are oriented such that the center of MIMO physical sectors  82 ,  84 , and  86  are respectively oriented at about 60, 180, and 300 degrees respectively. In this embodiment, the MIMO physical sectors do not substantial overlap. Each radio is set to the same channel, thus the MIMO physical sectors  82 - 86  each use the same channel. The wireless device embodiment of  FIGS. 9 and 10  may also be used to reduce interference with noise sources by selected one of the three MIMO physical sectors for communication. 
         [0051]    In another embodiment, not shown, wireless device  10  comprises a processor, four radios, an RF switch interfacing with each one radio, and four directional antennas interfacing with each one RF switch. Each antenna has an angle of coverage of about 90 degrees. The physical sectors of one antenna from each RF switch substantially overlap to form a MIMO physical sector resulting in a MIMO system having four MIMO virtual sectors. Each MIMO physical sector receives coverage from each one of the four radios. The physical sectors of the antennas are oriented in such a way that the MIMO physical sectors do not overlap and the MIMO physical sectors provide a combined angle of coverage of about 360 degrees. All radios are set to the same channel. 
         [0052]    In another embodiment, not shown, wireless device  10  comprises a processor, two radios interfacing with the processor, an RF switch interfacing with each one of the radios, and three directional antennas interfacing with each one RF switch. Each antenna has an angle of coverage of about 120 degrees. The physical sectors of one antenna from each one RF switch substantially overlap to form a MIMO physical sector resulting in a MIMO system having three MIMO virtual sectors. Each MIMO physical sector receives coverage from each one of the two radios. The physical sectors of the antenna are oriented in such a way that the MIMO physical sectors do not overlap and the MIMO physical sectors provide a combined angle of coverage of about 360 degrees. All radios are set to the same channel. 
         [0053]    In another embodiment, not shown, wireless device  10  comprises a processor, two radios interfacing with the processor, an RF switch interfacing with each one of the radios, and “N” directional antennas interfacing with each one RF switch. Each antenna has an angle of coverage of about 360 degrees divided by N. Two antennas, one from each RF switch, form a MIMO antenna, thereby forming N MIMO antennas. The physical sectors of the antennas that form each MIMO antenna substantially overlap to form N MIMO physical sectors. The MIMO physical sectors are oriented in such a way that the MIMO physical sectors do not substantially overlap, thereby providing a combined angle of coverage of about 360 degrees. All radios are set to the same channel. 
         [0054]    Radios, antennas, and MIMO physical sectors are not limited to using a single channel for communication or to forming MIMO physical sectors that are substantially non-overlapping. Radios may be grouped to provide MIMO physical sectors that use different channels. MIMO physical sectors that communicate on different channels may be positioned to overlap. Overlapping MIMO physical sectors that use different channels may simultaneously communicate less mutual interference. 
         [0055]    In one embodiment, referring to  FIG. 11 , wireless device  10  comprises a process  12 , controllers  14 ,  16  interfaces with processor  10 , two radios  18 ,  20  interface with controller  14  thereby forming a first radio group, two radios  22 ,  24  interface with controller  16  thereby forming a second radio group, an RF switch  26 ,  28 ,  30 ,  32  interfaces with radio  18 ,  20 ,  22 ,  24  respectively, antennas  34 - 48  interface with the RF switches in such a manner that two antennas interface with each one RF switch. The antennas may form MIMO antennas any manner; however, forming MIMO antennas using antennas from the same group enables MIMO physical sectors from different groups to operate on different channels. 
         [0056]    In one embodiment, antennas  34  and  36  form a first MIMO antenna. Antennas  42  and  44  form a second MIMO antenna. The first and second MIMO antennas belong to the first radio group. Antennas  38  and  40  form a third MIMO antenna. Antennas  46  and  48  form a fourth MIMO antenna. The third and fourth MIMO antennas belong to the second radio group. In another embodiment, antennas  34 - 40  form a first MIMO antenna and antennas  42 - 48  form a second MIMO antenna. 
         [0057]    The antennas and their respective physical sectors may have any angle of coverage and be oriented in any direction. The antennas of the various groups may form MIMO antennas in any manner. The resulting MIMO physical sectors may be overlapping or non-overlapping. In an exemplary embodiment, antennas  34 ,  36 ,  38 ,  40 ,  42 ,  44 ,  46 , and  48  and their respective physical sectors  58 ,  60 ,  62 ,  64 ,  66 ,  68 ,  70 , and  72  each have an angle of coverage of about 180 degrees. Referring to  FIGS. 11 and 12 , physical sector  58  substantially overlaps physical sector  60  to form MIMO physical sector  82 . Physical sectors  62  and  64  substantially overlap,  66  and  68  substantially overlap, and  70  and  72  substantially overlap to form MIMO physical sectors  84 ,  86 , and  88  respectively. The center of the angles of coverage of antennas  34 ,  36  and  38 ,  40  are oriented at about 90 degrees (e.g., up the page), thus MIMO physical sectors  82  and  84  overlap. The center of the angles of coverage of antennas  42 ,  44  and  46 ,  48  are oriented at about 270 degrees (e.g., down the page), thus MIMO physical sectors  86  and  88  substantially overlap. Radios  18  and  20  belong to the first radio group and radios  22  and  24  belong to the second radio group. Assigning channel C 1  to the first radio group and channel C 2  to the second radio group results in MIMO physical sectors  82  and  86  using channel C 1  and MIMO physical sectors  84  and  88  using channel C 2 . Thus, the channel assignment, the antenna orientation, and the MIMO antenna configurations provide overlapping MIMO physical sectors that use different channels. Referring to  FIG. 12 , MIMO physical sector  82  is assigned to C 1 , MIMO physical sector  84  is assigned to C 2 , and MIMO physical sector  82  substantially overlaps MIMO physical sector  84 . Because MIMO physical sectors  82  and  84  are assigned different channels, they may communicate with different wireless devices simultaneously with less mutual interference. MIMO physical sectors formed using antennas from different radio groups enables the MIMO physical sectors to overlap, be assigned different channels, and communicate simultaneously. MIMO antennas of the same radio group use the same channel. Interference between MIMO physical sectors formed using antennas from the same group may be reduced by, for example, positioning the MIMO physical sectors in such a way that they do not overlap and communicating using only one MIMO physical sector from the same group at any one time. 
         [0058]    In another embodiment, referring to  FIG. 11 , each one antenna  34 - 48  has a physical sector with an angle of coverage of about 90 degrees. Antennas are organized, as described above, to form four MIMO antennas. Antenna physical sectors are positioned such that the center of the angle of coverage for antennas pairs  34  and  36 ,  38  and  40 ,  42  and  44 , and  46  and  48  and their respective physical sectors are oriented at 45, 135, 225, and 315 degrees respectively. Channel C 1  is assigned to the first group radios and channel C 2  is assigned to the second group radios. The resulting four MIMO physical sectors are positioned to not substantially overlap and adjacent MIMO physical sectors are assigned a different channel. One MIMO physical sector from the first radio group and one MIMO physical sector from the second radio group may operate simultaneously. 
         [0059]    The antennas of wireless device  10  may be oriented to form MIMO virtual sectors. MIMO virtual sectors may have any angle of coverage and be oriented in any manner. A MIMO virtual sector may be selected for communication to decrease interference. In one embodiment, referring to  FIGS. 1 and 13 , antennas  34 - 38  and  42 - 46  have an angle of coverage of about 180 degrees. Antennas  34 ,  36 ,  38 ,  42 ,  44 ,  46  and the center of the angle of coverage of their respective physical sectors  58 ,  60 ,  62 ,  66 ,  68 ,  70  are oriented at 90, 150, 210, 270, 300, and 30 degrees respectively. The area between 0 and 60 degrees, marked as area  150  in  FIG. 13 , is covered by physical sectors  58 ,  68 , and  70 . Antennas  34 ,  44 , and  46  may function together as a MIMO antenna to transmit signals to and receive signals from any wireless device within area  150 . Areas  152 ,  154 ,  156 ,  158 , and  160  are respectively positioned between about 60-120 degrees, about 120-180 degrees, about 180-240 degrees, about 240-300 degrees, and about 300-0 degrees and are serviced respectively by antennas  34 ,  36 , and  46 ;  34 ,  36  and  38 ;  42 ,  36  and  38 ;  42 ,  44  and  38 ; and  42 ,  44  and  46 . Each one area  150 - 160  comprises a MIMO virtual sector. 
         [0060]    In an exemplary embodiment, referring to  FIGS. 1 and 13 , area  150  operates as a MIMO physical sector by forming a MIMO antenna using antennas  34 ,  44 , and  46 . Area  152  operates as a MIMO physical sector by forming a MIMO antenna using antennas  34 ,  36 , and  46 , and so forth for areas  154 - 160 . In this embodiment, areas  158  and  160  may not be combined to operate as a MIMO physical sector because area  158  requires antennas  42 ,  44 , and  38  to form a MIMO antenna while area  160  requires antennas  42 ,  44 , and  46  to form a MIMO antenna. Because RF switch  30  selects only one antenna at a time, MIMO physical sectors, for this embodiment, are limited to any combination of any one antenna associated with each RF switch. In this embodiment, wireless device  10  may select and communicate through any one MIMO virtual sector at any given time. The method of selecting the MIMO virtual sector consists of setting the RF switches to select the antennas that service the desired MIMO virtual sector. In another embodiment, an RF switch with its associated antennas may be replaced by a phased array. Antenna elements of each phased array may form MIMO antennas. 
         [0061]    Antennas may be oriented in any manner to form MIMO virtual sectors of any size. In an exemplary embodiment, referring to  FIG. 13 , each MIMO virtual sector  150 - 160  has an angle of coverage of about 60 degrees. In another embodiment, referring to  FIG. 14 , MIMO virtual sectors  150 ,  152 ,  154 ,  156 ,  158 , and  160  lie between 0-30 degrees, 30-60 degrees, 60-180 degrees, 180-210 degrees, 210-240 degrees, and 240-0 degrees respectively. In another embodiment, referring to  FIG. 15 , each MIMO virtual sector has an angle of coverage of about 40 degrees. MIMO virtual sectors  150 - 166  lie between 0-40 degrees, 40-80 degrees, 80-120 degrees, 120-160 degrees, 160-200 degrees, 200-240 degrees, 240-280 degrees, 280-320 degrees, and 320-0 degrees respectively. In another embodiment, referring to  FIGS. 11 and 18 , each MIMO virtual sector has an angle of coverage of about 90 degrees. Channel C 1  is assigned to the first group radios and channel C 2  is assigned to the second group radios. Antenna pairs  34  and  36 ,  38  and  40 ,  42  and  44 , and  46  and  48  respectively form MIMO antennas. MIMO virtual sectors formed by antennas  34 ,  36  and  42 ,  44  extend from 0-180 and 180-0 degrees respectively and are assigned channel C 1 . MIMO virtual sectors formed by antennas  38 ,  40  and  46 ,  48  extend from 90-270 and 270-90 degrees respectively and are assigned channel C 2 . The MIMO virtual sectors are positioned to form areas  150 - 156  which each receive coverage from two MIMO virtual sectors that operate on different channels. 
         [0062]    A wireless device may select and communicate through a MIMO virtual sector to improve performance. A wireless device may use any criteria for selecting a MIMO virtual sector for communication such as, for example, the presence of noise sources, noise source channels used, signal-to-strength ratio, direction of primary data flow, signal quality, signal strength, and data throughput. 
         [0063]    In one embodiment, referring to  FIGS. 9 and 17 , wireless device  10  desires to communicate with wireless device  102 . Wireless device  10  successively enables each antenna combination that forms each MIMO virtual sector  150 - 160 . Through each MIMO virtual sector, wireless device  10  measures its ability to communicate with wireless device  102 . Through at least MIMO virtual sector  150 , wireless device  10  detects the presence of noise source  110 . Through at least MIMO virtual sectors  154  and  156 , wireless device  10  detects the presence of noise sources  106  and  108  respectively. While communicating with wireless device  102 , wireless device  10  may reduce interference from noise sources  106  and  108  by selecting and communicating through MIMO virtual sector  150 . In the embodiment of wireless device  10  shown in  FIGS. 1 and 17 , areas adjacent to the selected MIMO virtual sector have at least one antenna in common, thus selecting a MIMO virtual sector does not disable all communication in other sectors, but communication within the selected MIMO virtual sector may provide increased performance than adjacent areas because it transmits and/or receives using all the antennas that form the MIMO antenna. 
         [0064]    Referring still to  FIGS. 1 and 17 , wireless device  10  may reduce interference from noise source  110  by selecting a channel that is different from the channel used by noise source  110 . In the event that wireless device  102  cannot switch to a channel that is not used by noise source  110 , communication with wireless device  102  may proceed using MIMO virtual sector  150  if it provides a desired level of performance. A wireless device may select any MIMO virtual sector that provides a desired level of performance. In this embodiment, wireless device  10  may select MIMO virtual sector  152  to communicate with wireless device  102 . Wireless device  10  may detect less interference from noise source  110  through MIMO virtual sector  152  than it detects through MIMO virtual sector  150 , but wireless device  10  may also receive a less desirable signal from wireless cell  102 . In the event that wireless device  10  desires to communicate with wireless device  104  and noise sources  106 ,  108 , and  110  all operate on the same channel as wireless device  104 , wireless cell  10  may reduce interference from the noise sources by selecting MIMO virtual sector  160  for communicating with wireless device  104 . A wireless device may select and use any MIMO virtual sector for any duration of time. A wireless device may switch from using one MIMO virtual sector to using any other MIMO virtual sector at any time and for any purpose. In an exemplary embodiment, referring to  FIG. 17 , wireless device  10  switches between MIMO virtual sectors  150  and  160  to communicate with wireless devices  102  and  104  respectively. Additionally, a wireless device may transmit through one MIMO virtual sector and receive through a different MIMO virtual sector. In another embodiment, referring to  FIGS. 11 and 18 , wireless device  10  may select the MIMO virtual sector that provides a desired level of communication for each area. Additionally, wireless device  10  may communicate with two wireless devices  104  and  120 , both in area  156 , simultaneously on different channels; for example, wireless device  104  communicates using channel C 1  while wireless device  120  communicates using channel C 2 . 
         [0065]    Unless contrary to physical possibility, the inventor envisions the methods and systems described herein: (i) may be performed in any sequence and/or combination; and (ii) the components of respective embodiments combined in any manner. 
         [0066]    This application incorporates by reference U.S. provisional application Ser. No. 60/484,800 filed on Jul. 3, 2003; U.S. provisional application Ser. No. 60/493,663 filed on Aug. 8, 2003; U.S. provisional application Ser. No. 60/692,490 filed on Jun. 21, 2005; U.S. utility application Ser. No. 10/869,201 filed on Jun. 15, 2004 and issued under U.S. Pat. No. 7,302,278; and U.S. utility application Ser. No. 10/880,387 filed on Jun. 29, 2004 and issued under U.S. Pat. No. 7,359,675, in their entirety for the teachings taught therein. 
         [0067]    The wireless cell can ask the advanced client to measure and report communication statistics such as, but not limited to, bit error rate, signal-to-noise ratio, dropped bits, signal strength, number of retransmission requests or any other environmental or communication parameter. Each antenna and antenna controller functions independently of the other antennas and controllers. 
         [0068]    The antenna controller sets the beam width, beam azimuth, beam steering, gain of the antenna and any other parameter available on adjustable antennas. The antennas are also capable of high-speed switching. The controllable characteristics of the antenna are dynamically modifiable. The antenna beam can steer directly at one receiving client during transmission then pointed at a second client when transmission to the second client begins. The beam width of the antenna can be increased or decreased as necessary; however, it is preferable to not increase the beam width to provide antenna coverage beyond the width of a sector. If the beam width is adjusted to provide coverage wider than a sector, the radio signal may interfere with adjacent or opposing sectors or wireless cells or detect clients not associated with the sector or wireless cell. The processor is responsible for tracking the antenna characteristics best suited to service each client in the sector covered by the antenna and to set the antenna controller to the parameters best suite for the particular client when communicating with the client. The use of an adjustable antenna, an antenna controller and a processor capable of controlling the antenna controller is not limited to the six-sector embodiment of a wireless network, but can also be used in a four-sector wireless cell or other wireless cell types. Preferably, the beam width would not exceed the width of the sector of the wireless cell in which it is used. 
         [0069]    MIMO antennas may use any combination of spatial, polarization, or angle antenna diversity. The MIMO antenna array may be fixed or adaptive for either transmit, receive, or both. When receiving, the MIMO antenna may use, for example, a maximum ratio combiner, an optimal linear combiner, selection diversity, or any combination of these methods or other methods for combining the signals from multiple antennas into a single signal. When transmitting, the MIMO antenna may use any type of encoding including, for example, OFDM, space-time-codes, or weighting of the antenna signals in the array to accomplish beam steering. 
         [0070]    During transmission or reception, all or any subset of antennas in the MIMO array may be used or selection diversity may be used to limit the number of antennas used. 
         [0071]    Antenna diversity may be used in the transmit path, in the receive path, or in both transmit and receive paths. The signal from each antenna, transmitted or received, may or may not be weighted. 
         [0072]    Servicing a physical sector with a MIMO antenna means that all antennas in the MIMO array use the channel assigned to the physical sector. Signal attenuation may be added after each antenna, after the signal combiner, or in the signal processor that manipulates the incoming signals. 
         [0073]    Although MIMO antennas are arrays of antennas, any antenna array may be used as a single antenna or a MIMO antenna may be used. For example, a directional antenna with about 120-degree angle of coverage may be replaced by an antenna array that provides similar coverage. The array may be fixed or adaptive. Adaptive arrays may use adaptive array weights to transmit directional beams within the angle and area of coverage to send a stronger signal to a desired client. During reception, an adaptive array may use array weights to direct a beam substantially towards the transmitting client and substantially null out any sources of interference. 
         [0074]    The processor, in exemplary embodiments, in addition to getting receive data from and sending transmit data to the radios, may also send instructions to control the radios such as, for example, instructing a radio to change channels or getting control information from the radios. In exemplary embodiments, the processor may also be capable of, for example, varying attenuation, controlling any or all RF switches, maintaining route tables, maintaining client specific information, and handing off mobile clients. 
         [0075]    In an exemplary embodiment, the processor may also control, for example, the attenuation or RF switches on a transmit or receive basis, a per client basis, a fixed period basis, and on a per demand basis. 
         [0076]    Some embodiments may have a network connection that may enable the wireless cell to communicate with a wired network. Some embodiments may have local storage to store, for example, transmit and receive date, relay data, video or audio data, environmental conditions data, and any other type of data required to service clients, function as a network, handoff or receive mobile clients, and forward information. 
         [0077]    When receiving, the MIMO antenna may use, for example, a maximum ratio combiner, an optimal linear combiner, selection diversity, or any combination of these methods or other methods for combining the signals from multiple antennas into a single signal. 
         [0078]    Assume for this example that the communication protocol uses packetized data and that the clients must transmit RTS and await a CTS before transmitting a single packet. It is possible to switch a client, or multiple clients, from a packet based communication protocol to a data stream protocol to increase the efficiency of long data transfers between clients. 
         [0079]    Another aspect of the invention is the use of multiple directional antennas, at least one radio, at least one attenuator and other electronic devices such as RF switches, packet switches, antenna sharing devices and other electronic and electrical components to generate various embodiments of wireless cells and wireless networks with differing characteristics and capabilities. 
         [0080]    Although there have been described preferred embodiments of this novel invention, many variations and modifications are possible and the embodiments described herein are not limited by the specific disclosure above, but rather should be limited only by the scope of the appended claims.