Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 11/355,491, filed Feb. 16, 2006. The disclosure of the above application is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to wireless networks, and more particularly to implementing multiple access points in a single device. 
       BACKGROUND OF THE INVENTION 
       [0003]    Referring now to  FIG. 1 , an internetwork  10  is shown that includes a first subnetwork  12 , a second subnetwork  14 , and a connection  16  to a distributed communications system  18 , such as the Internet. First subnetwork  12  includes a plurality of wireless stations  20 - 1 ,  20 - 2 , . . . ,  20 - n  that are associated with a first wireless access point (AP_A)  22 . Second subnetwork  14  includes a plurality of wireless stations  24 - 1 ,  24 - 2 , . . . ,  24 - m  that are associated with a second wireless access point (AP_B)  26 . AP_A  22  and AP_B  26  communicate with a switch  28  that routes data packets between first network  12 , second network  14  and distributed communications system  10 . 
         [0004]    Internetwork  10  is of typical construction in that AP_A  22  and AP_B  26  each include, in pertinent part, a media access controller (MAC) and a physical layer module (PHY) to form and communicate data packets over the wireless channel. 
       SUMMARY OF THE INVENTION 
       [0005]    A wireless network device includes a first media access controller (MAC) that generates a first output signal, a second MAC that generates a second output signal, and a communication channel. The communication channel includes a baseband processor in communication with a radio frequency transmitter and selectively transmits one of the first output signal and the second output signal. 
         [0006]    In other features the wireless network device includes a switch that routes one of the first output signal and the second output signal to the communication channel in accordance with a select signal. The communication channel generates a clear channel assessment signal that is communicated to the first MAC and the second MAC and determines when the first and second output signals can be generated. 
         [0007]    In other features an arbitration circuit determines which of the first output signal and the second output signal is transmitted by the communication channel. The determination is made based on a priority relationship between the first MAC and the second MAC. The first MAC and the second MAC generate respective first and second request signals that are communicated to the arbitration module. The first and second request signals indicate that the respective one of the first and second MACs desires to generate its respective one of the first and second output signals. 
         [0008]    In other features the arbitration module generates a first drop signal that is communicated to the first MAC and generates a second drop signal that is communicated to the second MAC. The first MAC and the second MAC each include a queue for data to be output through their respective first and second output signals. The first MAC and second MAC flush the data from their respective queue upon receiving their respective one of the first drop signal and the second drop signal. 
         [0009]    In other features the communication channel is otherwise compliant with at least one of the Institute of Electrical and Electronics Engineers (IEEE) standards 802.11, 802.11a, 802.11b, 802.11g, 802.11h, 802.11n, 802.16, and 802.20 and the Bluetooth standard issued by the Bluetooth Special Interest Group (SIG). 
         [0010]    A wireless network device includes first media access controller (MAC) means for generating a first output signal, second MAC means for generating a second output signal, and communication channel means including baseband processor means for communicating a selected one of the first and second output signals to radio frequency transmitting means for transmitting a radio-frequency modulated carrier based on the selected one of the first and second output signals. 
         [0011]    In other features the wireless network device includes switch means for routing the selected one of the first and second output signals to the communication channel means in accordance with a select signal. The communication channel means generates a clear channel assessment signal that is communicated to the first MAC means and the second MAC means and determines when the first and second output signals can be generated. 
         [0012]    In other features the wireless network device includes arbitration means for determining which of the first output signal and the second output signal is transmitted by the communication channel means. The determination is made based on a priority relationship between the first MAC means and the second MAC means. The first MAC means and the second MAC means generate respective first and second request signals that are communicated to the arbitration means. The first and second request signals indicate that the respective one of the first and second MAC means desires to generate its respective one of the first and second output signals. 
         [0013]    In other features the arbitration means generates a first drop signal that is communicated to the first MAC means and generates a second drop signal that is communicated to the second MAC means. The first MAC means and the second MAC means each include queue means for queuing data to be output through their respective first and second output signals. The first MAC means and second MAC means flushes the data from their respective queue means upon receiving their respective one of the first drop signal and the second drop signal. 
         [0014]    In other features the communication channel means is otherwise compliant with at least one of the Institute of Electrical and Electronics Engineers (IEEE) standards 802.11, 802.11a, 802.11b, 802.11g, 802.11h, 802.11n, 802.16, and 802.20 and the Bluetooth standard issued by the Bluetooth Special Interest Group (SIG). 
         [0015]    A method for generating a transmit signal in a wireless network device includes providing a first media access controller (MAC) that generates a first output signal in accordance with a first wireless network protocol, providing a second MAC that generates a second output signal in accordance with a second wireless network protocol, transmitting the first data packets and the second data packets from a common transmitter. 
         [0016]    In other features the method includes generating a select signal and routing one of the first and second output signals to the transmitting step in accordance with the select signal. The method also includes receiving a wireless network signal, generating a clear channel assessment signal that indicates one of the receiving and transmitting steps are executing; and generating the first and second output signal based on the clear channel assessment signal. 
         [0017]    In other features the method includes determining which of the first and second output signals is transmitted during the transmitting step based on a priority relationship between the first and second output signals. The method includes generating first and second request signals associated with respective ones of the first and second output signals, and asserting respective ones of the first and second request signals in association with generating the respective ones of the first and second output signals. 
         [0018]    In other features the method includes generating first and second drop signals associated with respective ones of the first and second output signals, maintaining first and second queues for data to be included in respective ones of the first and second output signals, and flushing a respective one of the first and second queues in response to a respective one of the first and second drop signals. 
         [0019]    In other features the transmitting step is otherwise compliant with at least one of the Institute of Electrical and Electronics Engineers (IEEE) standards 802.11, 802.11a, 802.11b, 802.11g, 802.11h, 802.11n, 802.16, and 802.20 and the Bluetooth standard issued by the Bluetooth Special Interest Group (SIG). 
         [0020]    In other features the first wireless network protocol is different from the second wireless network protocol. The first wireless network protocol includes an ad-hoc networking protocol and the second wireless network protocol includes an infrastructure mode protocol. 
         [0021]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0023]      FIG. 1  is a functional block diagram of an internetwork of the prior art; 
           [0024]      FIG. 2  is a functional block diagram of an improved internetwork; 
           [0025]      FIG. 3  is a functional block diagram of a system-on-chip (SOC); 
           [0026]      FIG. 4  is a flowchart of a method for controlling access to a communication channel of the SOC; 
           [0027]      FIG. 5A  is a functional block diagram of a high definition television; 
           [0028]      FIG. 5B  is a functional block diagram of a vehicle control system; 
           [0029]      FIG. 5C  is a functional block diagram of a cellular phone; and 
           [0030]      FIG. 5D  is a functional block diagram of a set top box. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the term module, circuit and/or device refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or or suitable components that provide the described functionality. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present invention. 
         [0032]    Referring now to  FIG. 2 , an improved internetwork  50  is shown. Internetwork  50  includes a networked appliance  52  that communicates with a first subnetwork  54 , a second subnetwork  56 , and a distributed communications system  58 , such as the Internet. In an example configuration, networked appliance  52  can be an audio/visual entertainment system. In the example configuration, first subnetwork  54  communicates real-time control data between remote control devices and second subnetwork  56  provides a wireless access point (WAP) to distributed communications system  58 . First subnetwork  54  and second subnetwork  56  can be configured to use different network modes. For example, first subnetwork  54  can be configured in an ad-hoc mode, and second subnetwork  56  can be configured in an infrastructure mode. 
         [0033]    Wireless networking protocols that may be used with first subnetwork  54  and second subnetwork  56  include the Institute of Electrical and Electronics Engineers (IEEE) standards 802.11, 802.11a, 802.11b, 802.11g, 802.11h, 802.11n, 802.16, and 802.20. First subnetwork  54  and second subnetwork  56  can also be operated as personal area networks such as Bluetooth. A Bluetooth standard is published by the Bluetooth Special Interest Group (SIG). The aforementioned standards are hereby incorporated by reference in their entirety. 
         [0034]    First subnetwork  54  includes a plurality of wireless stations (STAs)  60 - 1 ,  60 - 2 , . . . ,  60 - n , referred to collectively as STAs  60 , that are associated with a first media access controller (MAC 1 A)  62 . Second subnetwork  56  includes a plurality of wireless stations  64 - 1 ,  64 - 2 , . . . ,  64 - m , referred to collectively as STAs  64 , that are associated with a second media access controller (MAC 1 B)  66 . 
         [0035]    STAs  60  and  64  communicate with MAC 1 A  62  and MAC 1 B  66  through a communication channel  67  that includes an RF module  68  and a baseband processor  70 . An arbitration module  72  allows MAC 1 A  62  and MAC 1 B  66  to transmit through the single communication channel  67  as described below. MAC 1 A  62 , MAC  1 B  66 , arbitration module  72 , and baseband processor  70  can be implemented as part of a system-on-chip (SOC)  74 . 
         [0036]    MAC 1 A  62  and MAC 1 B  66  communicate with distributed communications system  58  through a third MAC  76 , PHY  78 , and a network switch  80 . PHY  78  and switch  80  can be compatible with a copper and/or fiber-optic Ethernet connection. In one embodiment, PHY  78  and switch  80  are compatible with a 100-BASET Fast Ethernet (FE) connection. MAC  76  and PHY  78  can also be implemented on SOC  74 , which can also include other components as will be described later. 
         [0037]    Networked appliance  52  can also include a first central processor unit (CPU 1 )  82  and memory  84 . Memory  84  stores computer programs such as operating systems and/or applications for operating networked appliance  52 . CPU 1   82  executes the computer programs stored in memory  84 . CPU 1   82  also includes a network link  86  that communicates with network switch  80 . Network link  86  allows CPU 1   82  to communicate with SOC  52 , first subnetwork  54 , second subnetwork  56 , and distributed communications system  58 . 
         [0038]    Referring now to  FIG. 3 , SOC  74  is shown in additional detail. SOC  74  can include a second central processor unit (CPU 2 )  100  that communicates with MAC 1 A  62 , MAC  1 B  66 , and MAC  76  through an internal bus  102 . CPU 2   100  routes data packets between MAC 1 A  62 , MAC  1 B  66 , and MAC  74  and is associated with memory  104  that stores one or more computer programs related to routing the data packets. 
         [0039]    Arbitration module  72  provides flow control logic for data packets transmitted from an OUT1 port of MAC 1 A  62  and an OUT2 port of MAC 1 B  66 . Arbitration module  72  includes a switch module  106  that receives data packets from OUT 1  and OUT  2  and selectively communicates one of them to an output  112  in accordance with a select signal  108 . An arbitration logic circuit  110  selects the MAC 1 A  62  and MAC  1 B  66  that gets access to communication channel  67  and generates select signal  108  accordingly. In one embodiment, arbitration logic circuit  110  determines priority between MAC 1 A  62  and MAC 1 B  66  according to a predetermined hierarchy. For example, arbitration logic circuit  110  can be configured to give priority to MAC 1 A  62  over MAC 1 B  66 . 
         [0040]    Arbitration module  72  generates a first clear channel assessment signal CCA 1  and a second clear channel assessment signal CCA 2 . The CCA1 signal is applied to MAC 1 A  62  and the CCA2 signal is applied to MAC 1 B  66 . The signals CCA 1  and CCA 2  change state (such as go low) to indicate the MAC 1 A  62  and MAC 1 B  66  that has access to communication channel  67  and change state (such as go high) to indicate that communication channel  67  is unavailable to the respective MAC 1 A  62  and MAC 1 B  66 . 
         [0041]    A first OR-gate  114  generates the CCA1 signal. First OR-gate  114  includes a first input that receives a CCA1′ signal from arbitration logic circuit  110  and a second input that receives a CCA signal  116  from baseband module  70 . Arbitration logic circuit  110  drives the CCA1′ signal high when MAC 1 A  62  is granted access to communication channel  67  and drives the CCA1′ signal low when MAC 1 A  62  is not granted access to communication channel  67 . Baseband module  70  drives CCA signal  116  high when communication channel  67  is busy transmitting or receiving and drives CCA signal  116  low when communications channel  67  is clear. 
         [0042]    A second OR-gate  118  generates the CCA 2  signal. Second OR-gate  118  includes a first input that receives a CCA2′ signal from arbitration logic circuit  110  and second input that receives CCA signal  116  from baseband module  70 . Arbitration logic circuit  110  drives the CCA2′ signal high when MAC 1 B  66  is granted access to communication channel  67  and drives the CCA2′ signal low when MAC 1 A  62  is not granted access to communication channel  67 . 
         [0043]    In general, second OR-gate  118  drives the CCA2 signal high when MAC 1 A  62  is granted permission to transmit over communication channel  67  and drives CCA 2  low after MAC 1 A  62  finishes transmitting. First OR-gate  114  drives the CCA1 signal high when MAC 1 B  66  is granted permission to transmit over communication channel  67  and drives CCA 1  low after MAC 1 B  66  finishes transmitting. 
         [0044]    MAC 1 A  62  and MAC 1 B  66  include respective internal transmit queues and assert respective request signals REQ 1  and REQ 2  when their respective queue contains data to be transmitted. The REQ1 and REQ2 signals are applied to arbitration logic circuit  110 . Upon receiving an asserted REQ1 or REQ2 signal, arbitration module  72  executes methods that are described below. A first method ( FIG. 4 ) determines whether one of MAC 1 A  62  and MAC 1 B  66  may access communication channel  67 . A second method (FIG.  5 ) determines whether arbitration logic circuit  110  should instruct MAC 1 A  62  and/or MAC 1 B to flush its respective queue and thereby drop the packet (dropped packets can be retried and/or re-sent according to a selected wireless protocol). Arbitration logic circuit  110  generates a DROP1 signal that is communicated to MAC 1 A  62  and generates a DROP2 signal that is communicated to MAC 1 B  66 . The DROP1 and DROP2 signals are asserted to indicate that the respective one of MAC 1 A  62  and MAC 1 B  66  should flush the data packet from its respective queue. MAC 1 A  62  and MAC 1 B simultaneously receive data from communication channel channel via an RX port  118  that is driven by baseband module  70 . 
         [0045]    Referring now to  FIG. 4 , a method  150  is shown for determining which of MAC 1 A  62  and MAC 1 B  66  is granted access to communication channel  67 . Method  150  can be executed by a central processing unit and/or or a logic circuit included in arbitration logic circuit  110 . Method  150  is executed when MAC 1 A  62  and/or MAC 1 B  66  asserts its associated request signal REQ 1 , REQ 2 . 
         [0046]    Control begins in block  152  and proceeds to decision block  154 . In decision block  154 , control determines whether REQ 1  and REQ  2  are being asserted simultaneously. If not, control branches to block  156  and clears CCA 1 ′ if MAC 1 A is requesting or clears CCA 2 ′ if MAC 1 B is requesting. Control then proceeds to block  158  sets the CCAx′ signal of the non-requesting MAC 1   x  so that it does not transmit while the requesting MAC 1   x  is transmitting. Control then exits through exit block  160 . 
         [0047]    Returning now to decision block  154 , if MAC 1 A and MAC 1 B are simultaneously requesting to send then control branches to block  162 . In block  162  control clears CCA 1 ′ if MAC 1 A has higher priority than MAC 1 B. If MAC 1 A has lower priority than MAC 1 B then control clears CCA 2 ′. Control then proceeds to block  164  and asserts the DROPx signal associated with the non-requesting MAC 1   x , thereby causing it to flush its queue. Control also sets the CCAx′ signal of the non-requesting MAC 1   x  so that it does not transmit while the requesting MAC 1   x  is transmitting. Control then exits through exit block  160 . 
         [0048]    Referring now to  FIGS. 5A-5D , various exemplary implementations of the present invention are shown. Referring now to  FIG. 5A , the present invention can be implemented in a high definition television (HDTV)  420 . The present invention may implement and/or be implemented in a WLAN interface  429 . The HDTV  420  also includes signal processing and/or control circuits, which are generally identified at  422 , that communicate with the WLAN interface  429 . The signal processing and/or control circuits  422  also communicate with mass data storage  427 . 
         [0049]    The HDTV  420  receives HDTV input signals in either a wired or wireless format and generates HDTV output signals for a display  426 . In some implementations, signal processing circuit and/or control circuit  422  and/or other circuits (not shown) of the HDTV  420  may process data, perform coding and/or encryption, perform calculations, format data and/or perform any other type of HDTV processing that may be required. 
         [0050]    The mass data storage  427  stores data in a nonvolatile manner such as optical and/or magnetic storage devices. At least one of the magnetic storage devices may be a mini hard disk drive (mini HDD) that includes one or more platters having a diameter that is smaller than approximately 1.8″. The HDTV  420  may be connected to memory  428  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The HDTV  420  also may support connections with a plurality of WLANs via a WLAN network interface  429 . 
         [0051]    The HDTV  420  may include a power supply and/or power conditioning circuit  423  that applies power to the other components of the HDTV  420 . 
         [0052]    Referring now to  FIG. 5B , the present invention may implement and/or be implemented in a WLAN interface  448  of a vehicle  430 . The WLAN interface  448  communicates with one or more vehicle control systems, mass data storage of the vehicle control system and/or a power supply  433 . In some implementations, the vehicle control systems include a powertrain control system  432  that receives inputs from one or more sensors such as temperature sensors, pressure sensors, rotational sensors, airflow sensors and/or any other suitable sensors and/or that generates one or more output control signals such as engine operating parameters, transmission operating parameters, and/or other control signals. 
         [0053]    The vehicle control systems may also include other control systems  440  of the vehicle  430 . The control systems  440  may likewise receive signals from input sensors  442  and/or output control signals to one or more output devices  444 . In some implementations, the control system  440  may be part of an anti-lock braking system (ABS), a navigation system, a telematics system, a vehicle telematics system, a lane departure system, an adaptive cruise control system, a vehicle entertainment system such as a stereo, DVD, compact disc and the like. Still other implementations are contemplated. 
         [0054]    The powertrain control system  432  may communicate with mass data storage  446  that stores data in a nonvolatile manner. The mass data storage  446  may include optical and/or magnetic storage devices for example hard disk drives (HDDs) and/or DVDs. At least one of the magnetic storage devices may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The powertrain control system  432  may be connected to memory  447  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The powertrain control system  432  also may support connections with a plurality of WLANs via WLAN network interface  448 . The control system  440  may also include memory  447 . 
         [0055]    Referring now to  FIG. 5C , the present invention can be implemented in a cellular phone  450  that may include a cellular antenna  451 . The present invention may implement and/or be implemented in WLAN interface  468 . The WLAN interface  468  communicates with either or both signal processing and/or control circuits, which are generally identified in  FIG. 5C  at  452 . The cellular phone  450  may also include mass data storage  464  and/or a power supply  453 . In some implementations, the cellular phone  450  includes a microphone  456 , an audio output  458  such as a speaker and/or audio output jack, a display  460  and/or an input device  462  such as a keypad, pointing device, voice actuation and/or other input device. The signal processing and/or control circuits  452  and/or other circuits (not shown) in the cellular phone  450  may process data, perform coding and/or encryption, perform calculations, format data and/or perform other cellular phone functions. 
         [0056]    The cellular phone  450  may communicate with the mass data storage  464  to store data in a nonvolatile manner such as on optical and/or magnetic storage devices for example hard disk drives (HDDs) and/or DVDs. At least one of the magnetic storage devices may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The cellular phone  450  may be connected to memory  466  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. 
         [0057]    Referring now to  FIG. 5D , the present invention can be implemented in a set top box  480 . The present invention may implement and/or be implemented in a WLAN interface  496 , which communicates with either or both signal processing and/or control circuits generally identified at  484 . The control circuits  484  can also communicate with mass data storage  490  of the set top box  480  and/or a power supply  483 . The set top box  480  receives signals from a source such as a broadband source and outputs standard and/or high definition audio/video signals suitable for a display  488  such as a television and/or monitor and/or other video and/or audio output devices. The signal processing and/or control circuits  484  and/or other circuits (not shown) of the set top box  480  may process data, perform coding and/or encryption, perform calculations, format data and/or perform any other set top box function. 
         [0058]    The set top box  480  may communicate with mass data storage  490  that stores data in a nonvolatile manner. The mass data storage  490  may include optical and/or magnetic storage devices for example hard disk drives (HDDs) and/or DVDs. At least one of the magnetic storage devices may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The set top box  480  may be connected to memory  494  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The set top box  480  also may support connections with a plurality of WLANs via a WLAN network interface  496 . Still other implementations in addition to those described above are contemplated. 
         [0059]    Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.

Technology Category: 5