Patent Document

This application is a continuation of U.S. patent application Ser. No. 12/969,954, filed on Dec. 16, 2010, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments pertain to communication networks. Some embodiments pertain to wireless personal area networks (WPANs) and wireless local area networks (WLANs) that use millimeter-wave frequencies to communicate. Some embodiments relate to millimeter-wave networks operating in accordance with the wireless gigabit alliance (WiGig) specification and the IEEE 802.11ad specification for very-high throughput in 60 GHz. Some embodiments relate to millimeter-wave networks that operate in accordance with IEEE 802.15.3 specification for high-rate WPANs. 
     BACKGROUND 
     The millimeter-wave band has the available spectrum and is capable of providing significantly higher-level throughputs than the microwave frequency band. Due to significantly higher attenuation levels and the directional nature of millimeter-wave signals, millimeter-wave devices (i.e., stations) generally employ highly-directional antennas as well as beamforming techniques for communicating. Some key usages of the millimeter-wave frequency band may include transmissions to a wireless display, wireless docking, sync &amp; go, real-time video streaming, and high-definition television (HDTV) streaming, among others. To enable these key usages, millimeter-wave devices may need to discover each other and exchange capability and service information. This is more difficult in a millimeter-wave network due to the need for highly-directional antennas and beamforming techniques. 
     Thus, there are general needs for millimeter-wave stations and methods for station and information discovery in a millimeter-wave network. What is also needed is a simplified and unified frame-format scheme for both station and information discovery suitable for use in a millimeter-wave WPAN or in a millimeter-wave WLAN. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a millimeter-wave (mm basic-service set (BSS), in accordance with some embodiments; 
         FIG. 2  illustrates communications between the central coordinator and a non-central coordinator station, in accordance with some embodiments; 
         FIG. 3  illustrates communications between two non-central coordinator stations, in accordance with some embodiments; 
         FIG. 4  illustrates a station-capability information element (IE), in accordance with some embodiments; 
         FIG. 5  illustrates an information-request action frame, in accordance with some embodiments; 
         FIG. 6  illustrates an information-response action frame, in accordance with some embodiments; and 
         FIG. 7  illustrates a functional block diagram of a millimeter-wave station, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. 
       FIG. 1  illustrates a mmW BSS, in accordance with some embodiments. The mmW BSS  100  includes a plurality of mmW stations  104  that may communicate using millimeter waves. One of the mmW stations  104 , the central coordinator  102 , may operate as central coordinator for the mmW BSS  100  to coordinate communications among the mmW stations  104  and control access to the wireless medium. 
     In some embodiments, the central coordinator  102  may broadcast a beacon frame that indicates the length of a beacon interval during which communications are to take place. The beacon frame may be received by the other mmW stations  104 , thereby allowing the other mmW stations  104  to know when the next beacon interval will occur. The central coordinator  102  and the mmW stations  104  may utilize directional antennas and may employ beamforming, beam steering or beam directing techniques to communicate therebetween. These embodiments are described in more detail below. 
     In accordance with some embodiments, a simplified and unified frame-format scheme for both station and information discovery is provided. The frame-format scheme may be suitable for use in both a mmW WPAN and a mmW WLAN. As described in more detail below, through the use of a station-capability information element, an information-request action frame, and an information-response action frame, the mmW stations  104  of the mmW BSS  100  may be able to discover each other and exchange station-capability information so that non-central coordinator devices, such as mmW station  104 A and mmW station  104 B, can communicate directly in a peer-to-peer (P2P) manner. 
     In some embodiments, the central coordinator  102  and the mmW stations  104  are configured to operate as part of a personal BSS (PBSS). The central coordinator  102  may be a PBSS control point (PCP) operating as a central coordinator for the PBSS, and the PBSS may be configured to operate in accordance with a Wireless Gigabit Alliance (WiGig or WGA) specification or an IEEE 802.11 specification such as the Task Group ad (IEEE 802.11ad) draft specification for multi-gigabit speed wireless communications technology operating over an unlicensed 60 GHz frequency band. The PBSS may be configured to operate in accordance with the WiGig Media-Access Control (MAC) or Physical Layer (PHY) specifications, version 1.0 or later, although this is not a requirement. In some other embodiments, the PBSS may be configured to operate in accordance with an IEEE 802.15.3 specification for high-rate WPANs, including the IEEE 802.15.3 Task Group 3c (TG3c). 
     In some embodiments, the central coordinator  102  and the mmW stations  104  comprise an infrastructure BSS (IBSS). The central coordinator  102  may be an access point (AP) operating as a central coordinator for the IBSS. The IBSS may be configured to operate in accordance with the WiGig specification or the IEEE 802.11ad specification referenced above. 
     The mmW stations  104  may include wireless display devices, laptop and portable computers, mobile communication devices (e.g., cell phones, smart phones or personal digital assistant (PDAs)), hard drives and other storage devices, digital audio players (e.g., MP3 players), web tablets, wireless headsets, pagers and instant messaging devices, digital cameras, televisions, medical devices (e.g., a heart rate monitor, a blood pressure monitor, etc.), or other device that may receive and/or transmit information using millimeter waves. 
     Through the use of the frame-format scheme described herein, the mmW stations  104  may discover each other and exchange station-capability information, which may allow for P2P communications therebetween. For example, wireless docking and sync &amp; go techniques for a laptop computer may be achieved. Furthermore, a laptop computer will be able to determine that a wireless display device is indeed a display and not a wireless hard drive, for example, which will allow for wireless use of the display by the laptop computer. A cell phone may be able to discover and determine the capabilities of an MP3 player so that it can synchronize music files with the MP3 player. The mmW stations  104  associated with a laptop (which may be operating as the central coordinator  102 ) may be able to discover, each other, learn each other&#39;s capabilities, and subsequently establish wireless connections therebetween. 
     In a conventional WLAN or WiFi network configured in accordance with conventional IEEE 802.11 specifications, station and service discovery are less important since WEAN devices use microwave frequencies (which are less directional the mmW frequencies) and because WLAN devices are generally configured to communicate directly with an access point. 
       FIG. 2  illustrates communications between a central coordinator  102  and anon-central coordinator station  104 A, in accordance with some embodiments. A non-central coordinator station, such as mmW station  104 A ( FIG. 1A ), may be configured to transmit a station-capability IE  204  to the central coordinator  102  during association  202  with the BSS  100  ( FIG. 1 ). The station-capability IE  204  may be configured to provide station-capability information to the central coordinator  102 . The non-central coordinator station  104 A may also be configured to transmit an information-request action frame  206  to a target station to either discover or request information about the one or more other mmW stations  104  ( FIG. 1 ) of the BSS  100 . The target station may be either the central coordinator  102  (as illustrated in  FIG. 2 ) or one of the other mmW stations (e.g., non-central coordinator station  104 B ( FIG. 1 )). The non-central coordinator station  104 A may receive an information-response action frame  208  from the target station (e.g., the central coordinator  102 ) that includes the requested information. 
     In some embodiments, an unsolicited information-response action frame  210  may be sent unsolicited (i.e., not in response to an information-request action frame  206 ) by one of the mmW stations  104 , such as by the central coordinator  102 , to provide updated information to the mmW stations  104  of the BSS  100 . In some of these embodiments, the unsolicited information-response action frame  210  may be transmitted by the central coordinator  102  to the associated mmW stations  104  upon association of a new mmW station  104  with the BSS  100  or upon disassociation of a mmW station  104  with the BSS  100 . The unsolicited information-response action frame  210  may include station-capability information of all currently associated mmW stations  104  and may include the station-capability information of the central coordinator  102 . An unsolicited information-response action frame  210  may also be sent at any time by the central coordinator  102 . 
     In these embodiments, the transmission of the unsolicited information-response action frame  210  by the central coordinator  102  to all mmW stations  104  associated with BSS  100  allows currently associated mmW stations  104  to maintain up-to-date information about the other currently associated mmW stations  104 . An unsolicited information-response action frame  210  may also be sent by a non-central coordinator station  104  to provide an information update directly to one or more other non-central coordinator stations  104  in the BSS  100 . 
     As described in more detail below, the station-capability information provided in the station-capability IE  204 , requested and/or provided in the information-request action frame  206 , or provided in the information-response action frame  208  allows a mmW station  104  to know the capabilities of other mmW stations  104 . The station-capability information may include one or more of beamforming capabilities, the number of antennas and antenna capabilities, the number of elements per antenna, supported modulations and modulation capabilities, supported channels, and multi-user (MU) multiple-input output (MIMO) capabilities, among other things. This exchange of information may allow any non-central coordinator station  104  to subsequently perform beamforming training for subsequent communication therebetween. 
       FIG. 3  illustrates communications between two non-central coordinator stations, in accordance with some embodiments. An initiating non-central coordinator station  304 A may transmit an information-request action frame  306  to another non-central coordinator station  304 B to either discover or request information about the other the other non-central coordinator station  304 B. The other non-central coordinator station  304 B may be configured to respond by transmitting an information-response action frame  308  that includes the requested information. In some embodiments, the initiating non-central coordinator station  304 A may transmit the information-request action frame  306  to the other non-central coordinator station  304 B after the initiating non-central coordinator station  304 A has received station-capability information about the other non-central coordinator station  304 B from the central coordinator  102  ( FIG. 1 ), although this is not a requirement. 
     The initiating non-central coordinator station  304 A may correspond to non-central coordinator station  104 A ( FIG. 1 ) and the other non-central coordinator station  304 B may correspond to non-central coordinator station  1049  ( FIG. 1 ). 
       FIG. 4  illustrates a station-capability IE, in accordance with some embodiments. Station-capability IE  400  may be suitable for use as station-capability IE  204  ( FIG. 2 ) and may be transmitted from one mmW station  104  ( FIG. 1 ) to another mmW station  104  to provide station-capability information to the other mmW station  104 . In some embodiments, the station-capability IE  400  may be transmitted by a mmW station  104  to the central coordinator  102  ( FIG. 1 ) during association  202  ( FIG. 2 ) with the BSS  100  ( FIG. 1 ) to provide station-capability information to the central coordinator  102 . 
     In some embodiments, one or more station-capability FE  400  may be included as part of the information-request action frame  206  ( FIG. 2 ) or the information-request action frame  306  ( FIG. 3 ) to provide station-capability information within the frame. One or more station-capability IE  400  may also be included as part of the information-response action frame  208  ( FIG. 2 ) or the information-response action frame  308  ( FIG. 3 ) to provide station-capability information within the frame. 
     In accordance with some embodiments, the station-capability if  400  may include a station (STA) address  402  of the sending mmW station (e.g., mmW station  104 A (FIG.  1 )), an association identifier (AID)  404  of the sending mmW station, and station-capability information  406  of the sending mmW station. The station address  402  may be a MAC address of the sending mmW station, and the association ID  404  may have been assigned by the central coordinator  102  during association  202 . The station-capability information  406  may include station-capability information of the sending mmW station and may include at least some basic capabilities of the sending mmW station. As discussed in more detail below, the information included in the station-capability IE  400  may be distributed by the central coordinator  102  in an information-response action frame  208  ( FIG. 2 ) when requested or in an unsolicited information-response action frame  210  ( FIG. 2 ). 
       FIG. 5  illustrates an information-request action frame  500 , in accordance with some embodiments. Information-request action frame  500  may be suitable for use as information-request action frame  206  ( FIG. 2 ) and information-request action frame  306  ( FIG. 3 ). In some embodiments, a sending mmW station, such as non-central coordinator station  104 A ( FIG. 1 ), may transmit the information-request action frame  500  to a target station to either discover or request information about the one or more other mmW stations  104  ( FIG. 1 ) in the BSS  100  ( FIG. 1 ). The target station may be either the central coordinator  102  ( FIG. 1 ) or one of the other mmW stations (e.g., non-central coordinator station  104 B). 
     In some embodiments, the information-request action frame  500  may also include station-capability information of the sending mmW station. The sending mmW station may also configure the information-request action frame  500  to include station-capability information of other mmW stations  104  that are known to the sending mmW station, in addition to the station-capability information of the sending mmW station. The information-request action frame  500  may allow the sending mmW station to either discover other mmW stations  104  or request information about the one or more other mmW stations  104  of the BSS  100 . 
     In some embodiments, the information-request action frame  500  includes at least a target address field  503  and a request IE field  504 . The target address field  503  may include an address of the target station, and the request IE field  504  may be configured to indicate the types of information elements that the sending mmW station is requesting from the target station (e.g., either the central coordinator  102  or anon-central coordinator station such as mmW station  104 B). 
     When the information-request action frame  500  is transmitted to the central coordinator  102  (as illustrated in  FIG. 2 ) and when the target address field  503  includes a broadcast address, the sending mmW station may be requesting information about all the other mmW stations  104  that are associated with the central coordinator  102 . The request IE field  504  may allow the sending mmW station to specify which types of IEs are being requested from the target station. In some embodiments, almost any type of IE may be requested in the request IE field  504 . 
     As further illustrated in  FIG. 5 , the information-request action frame  500  may also include a category field  501  to indicate that the information-request action frame  500  is a frame applicable to a mmW BSS, and an action field  502  to indicate that information-request action frame  500  is requesting information. In some embodiments, category field  501 , action field  502 , and request IE field  504  may be configured in accordance with section 7.3.2.12 of the IEEE 802.11ad specification, although this is not a requirement. 
     When the information-request action frame  500  is transmitted to another non-central coordinator station, such as non-central coordinator station  304 B (as illustrated in  FIG. 3 ), the target address field  503  may include a MAC address of the other non-central coordinator station  104 B indicating that the sending mmW station is requesting information about the other non-central coordinator station  104 B directly from the other non-central coordinator station  104 B. Accordingly, peer non-central coordinator stations may discover each other and request information about each other. Furthermore, this exchange of information may allow direct-link setup (DLS) performed between peer non-central coordinator stations. 
     Accordingly, an information-request action frame  500  may be used by a mmW station  104  to request information about either a single station in the BSS  100  or about all of the associated mmW stations  104  in the BSS  100 . If a mmW station  104  is requesting information about only a single mmW station  104  in the BSS  100  ( FIG. 1 ), the requesting station may set the target address field  503  in the frame to the MAC address of that single mmW station  104 . If a mmW station  104  is requesting information about all of the mmW stations  104  in the BSS  100 , it may set the target address field  503  in the frame to the broadcast address and may transmit the information-request action frame  500  to the central coordinator  102 . 
     In some embodiments, the information-request action frame  500  may also include a station-capability field  505  that includes station-capability information about the sending mmW station (i.e., the source station) and station-capability information about other mmW stations  104  that are known to the sending mmW station. The information-request action frame  500  may also include an optional IE-provided field  506  that includes an actual IE that the sending mmW station is providing to the target station. In these embodiments, an information-request action frame  500  may provide the capabilities and any other IEs of the sending mmW station (i.e., the source station). This reduces the number of handshakes between the two mmW stations  104 . 
     As illustrated in  FIG. 5 , a station-capability field  505  may be included in the information-request action frame  500  for each mmW station for which station-capability information is being provided. As also illustrated in  FIG. 5 , an IE-provided field  506  may also be provided for each IE that is provided. As also illustrated in  FIG. 5 , one or more vendor-specific IE  507  may also be included in the information-request action frame  500 . Accordingly, a simplified and unified frame-format scheme for both station and information discovery suitable for use in a mmW WPAN or a mmW WLAN is provided. 
       FIG. 6  illustrates an information-response action frame  600 , in accordance with some embodiments. The information-response action frame  600  may be suitable for use as information-response action frame  208  ( FIG. 2 ) or information-response action frame  308  ( FIG. 3 ). The information-response action frame  600  may transmitted by a mmW station either unsolicited or in response to receipt of the information-request action frame  500  ( FIG. 5 ). When the information-response action frame  600  is sent in response to an information-request action frame  500 , it may be referred to as a solicited information-response action frame because it was requested by another mmW station. When the information-response action frame  600  is not sent in response to an information-request action frame  500 , it may be referred to as an unsolicited information-response action frame  210  ( FIG. 2 ). 
     In accordance with the embodiments illustrated in  FIG. 6 , the information-response action frame  600  may include a target address field  603  and a request IE field  604 . The target address field  603  may include an address of a target station (i.e., that station that is to receive the information-response action frame  600 ) when the information-response action frame  600  is solicited. The target address field  603  may include a broadcast address when the information-response action frame  600  is unsolicited. 
     The request IE field  60 . 4  may be configured to indicate the types of information elements that are being provided in the information-response action frame  600 . The information-response action frame  600  may also include one or more optional station capability fields  605  to indicate station capability of one or more mmW stations  104 . The information-response action frame  600  may also include one or more optional IE-provided fields  606  to include the actual information elements that the mmW station  104  transmitting the information-response action frame  600  is providing to the mmW station  104  receiving the information-response action frame  600 . As also illustrated in  FIG. 6 , the information-response action frame  600  may also include a category field  601 , an action field  602 , and one or more vendor-specific fields  607 , similar to fields  501 ,  502  and  507 , respectively, as discussed above. 
       FIG. 7  illustrates a functional block diagram of a mmW station  700 , in accordance with some embodiments. The mmW station  700  may be suitable for use as any one of mmW stations  104  ( FIG. 1 ), including the central coordinator  102  ( FIG. 1 ). The mmW station  700  may include one or more antennas  701  that may be configured for communicating millimeter wave signals either in a directional manner or in a non-directional manner. In accordance with embodiments, the mmW station  700  may configure the antennas  701  for non-directional communications for establishing an initial contact with another mmW station, and may configure the antennas  701  for directional communications after establishing an initial contact with the other mmW station. In these embodiments, station-capability information received from the other station or received from the central coordinator  102  may be used for the directional communications. In some embodiments, beam-forming training may be performed and beamforming coefficients may be employed for the directional communications. 
     The mmW station  700  may include mmW PHY layer  702 , MAC layer  704 , and memory  706 . In some embodiments, the mmW station  700  may implement the mmW PHY layer  702  and the MAC layer  704  in accordance with a WiGig PEW and MAC specifications (or the IEEE 802.11ad specification) for multi-gigabit speed wireless communications technology operating over the unlicensed 60 GHz frequency band. Memory  706  may be configured to store, among other things, the station-capability information received from other mmW stations for use in communicating with the other mmW stations. 
     Although mmW station  700  is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs) and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of mmW station  700  may refer to one or more processes operating on one or more processing elements. 
     Antennas  701  may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some MIMO embodiments, antennas  701  may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result between each of antennas  701  and the antennas of a sending mmW station. In some MIMO embodiments, antennas  701  may be separated by up to 1/10 of a wavelength or more. 
     In some embodiments, the mmW station  700  may be configured to perform association beam-forming training (A-BFT) with collision avoidance, in accordance with U.S. patent application Ser. No. 12/559,770, filed Sep. 15, 2009, entitled “MILLIMETER-WAVE COMMUNICATION STATION AND METHOD FOR SCHEDULING ASSOCIATION BEAMFORMING TRAINING WITH COLLISION AVOIDANCE,” In some embodiments, the mmW station  700  may be configured to perform multiple-access beamforming and beamforming training in accordance with U.S. patent application Ser. No. 12/574,140, filed Oct. 6, 2009 entitled “MILLIMETER-WAVE COMMUNICATION STATION AND METHOD FOR MULTIPLE-ACCESS BEAMFORMING IN A MILLIMETER-WAVE COMMUNICATION NETWORK.” 
     Referring to  FIGS. 1-6 , in accordance with some embodiments, the mmW stations  104  and the central coordinator  102  may implement a set of protocol procedures. For example, a sending mmW station  104  may transmit an information-request action frame  500  to a destination station  104  in the BSS  100  with a length field of the request IE  504  set to zero to determine if the destination mmW station is still present in the BSS  100  and is within range of the sending mmW station  104 . 
     A sending mmW station  104 , such as non-central coordinator station  104 A, may transmit an information-request action frame  500  that includes its station-capability information element  400  and other information elements. However, a sending mmW station  104 , such as non-central coordinator station  104 A, may be prohibited from including the station-capability information of another station within an information-request action frame  500 . 
     As discussed above, a sending mmW station  104  may transmit an information-response action frame  600  either as a response to an information-request action frame  500 , or it may be sent unsolicited. If the sending mmW station  104  is providing information about a single other mmW station of the BSS  100 , the sending mmW station  104  may set the target address field  603  in information-response action frame  600  to a MAC address of that single other mmW station. If a sending mmW station  104  is providing information about all of the stations in the BSS  100  in the information-response action frame  600 , it may set the target address field  603  in information-response action frame  600  to the broadcast address. 
     In accordance with some embodiments, a responding station  104  (either a station  104  or the central coordinator  102 ) may be configured to include, an information-response action frame  600 , the information elements that were requested by the station requesting the information. A responding station (either a station  104  or the central coordinator  102 ) may also be configured to send an information-response action frame  600  with an empty payload in response to a received information-request action frame  500  for which the requesting mmW station solicits information about a single station that is not a member of the BSS  100  and the responding station is the central coordinator  102  (or that is not the responding station itself). Otherwise, the responding station may send an information-response action frame  600  with the information requested by the requesting station. 
     Embodiments may be implemented in one or a combination of hardware, firmware and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transistor mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. In some embodiments, system  100  may include one or more processors and may be configured with instructions stored on a computer-readable storage device. 
     The Abstract is provided to comply with 37 C.F.R. Section 1.72(b) requiring an abstract that will allow the reader to ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Technology Category: h