Abstract:
Methods are disclosed for management-packet communication using management frames between various combinations of stations and access points to share application data, for example, a GPS ephemeris and/or its position data for at least one GPS satellite. The management-packet communications may push the application data, or operate in a pull mode based upon availability and requests. The methods may use infrastructure messaging and/or ad hoc or peer to peer messaging schemes. The apparatus supporting these methods include embodiments of integrated circuits, processors, program systems, installation packages, computer readable memories and servers.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the priority date of the U.S. provisional patent application Ser. No. 61/332,640, filed May 7, 2010 entitled Management-Packet Communications of GPS Satellite Positions, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This invention relates to dissemination of application data, in particular Global Positioning System (GPS) ephemeris position data about GPS satellites, through management-packet communication using Wireless Local Area Networks (WLAN). 
     BACKGROUND OF THE INVENTION 
     The reception of GPS satellite position data, used to create a position data (i.e., ephemeris data) in hybrid GPS/WLAN devices, may have problems indoors and in urban canyons. There is a need to wirelessly communicate such application data in coverage problem areas. Most, but not all, wireless communication in a WLAN is done by connection between an access point and stations. It would seem natural to consider connection-based solutions to these coverage problems. 
     Connection-based solutions for Assisted GPS (A-GPS) for GPS/WLAN devices exist, often disseminating the ephemeris via an (Internet Protocol) IP network from a server. They tend to be inconvenient, requiring the user to connect to a wired network in the home or office, or to use a wireless broadband connection in the home, office, or a hotspot. Many people do not have subscriptions. And explicit connection and download are cumbersome and time consuming. 
     Another connection-based solution is A-GPS via cellular Secure User Plane Location (SUPL) connection requiring cellular network subscription with tariffs, adding cost. This typically limits A-GPS capability to a single device (usually the user&#39;s personal phone) that is not available to the user&#39;s other devices, which may not have cellular network capability. 
     These connection-based solutions often rely on a web-based assistance server that is vulnerable to loss of connection to the server, web attacks on the server such as denial of service, and/or server failure through the financial insolvency of the server provider. Such connections usually require access permission, often involving log-on and/or an authentication processes. 
     SUMMARY OF THE INVENTION 
     Application data, such as an ephemeris of Global Positioning System (GPS) satellite positions, may be shared, without connection to a Wireless Local Access Network (WLAN), by management-packet communication between a station near an access point, and/or between access points, and/or between stations. The WLAN may be compatible with at least one wireless communication protocol that may comply with a version of an Institute for Electrical and Electronic Engineers (IEEE) 802.11 standard. 
     Management-packet communication of application data uses only management frames or packets to wirelessly communication the application data. It does not use standard connection based communications. The station does not need to connect or even know there is an access point nearby. The transfer of the application data requires no log-on, no authentication, no access permission and no need for the Internet. A station passing close to the access point suffices to transfer the ephemeris. 
     Two basic approaches may be implemented, a push and a pull approach. The push approach communicates the application data without a request. The pull approach first communicates a request and then communicates the application data in response to the request. The receiving device, whether an access point or a station, may respond with its application data if the beacon makes the request or with a request for the application data, if the beacon notes its availability. 
     An integrated circuit may support management-packet communications with a processor configured to support the WLAN and use management frames to communicate application data. The integrated circuit may be part of the access point and/or of the station. The processor may be further configured to use a beacon frame and/or its Information Element to communicate the application data, its availability, and/or request the application data. 
     The processor may include at least one instance of a finite state machine, a computer and/or a computer accessible memory configured for access by the computer to retrieve a program system to perform management-packet communication. Other embodiments include a computer readable memory and/or a server configured to communicate the program system and/or an installation package for installing the program system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a simplified block diagram of a Wireless Local Access Network (WLAN) using the push approach to management-packet communication to share application data such as an ephemeris of position data for at least one Global Positioning System (GPS) satellite among at least one station and/or at least one access point. 
         FIG. 2  shows a transaction diagram of the pull approach to management-packet communication between a station and an access point of  FIG. 1 . 
         FIG. 3  shows that the WLAN may be compatible with at least one wireless communication protocol that may in some cases be a form of the IEEE 802.11 standard. 
         FIG. 4  shows the processor may include at least one finite state machine, computer and/or computer accessible memory configured for access by the computer to retrieve a program system instructing the processor to perform management-packet communication. It also shows a computer readable memory and/or a server configured to communicate the program system and/or an installation package. 
         FIG. 5  shows some details of the program system of  FIG. 4  implementing management-packet communication. 
     
    
    
     DETAILED DESCRIPTION 
     This invention relates to dissemination of application data, in particular, Global Positioning System (GPS) ephemeris position data about GPS satellites through management-packet communication using Wireless Local Area Networks (WLAN). As will be described below, in one embodiment, management-packet communication may occur without connecting to the WLAN. The ephemeris may be shared using the WLAN by performing management-packet communication between a station near an access point, and/or between a first and a second access point, and/or between a first and a second station. Management-packet communication may use only the management packets or frames of a wireless communications protocol employed by the WLAN. This use may involve only a part of the management frame, such as the information element of a beacon frame. 
     Referring to the drawings more particularly by reference numbers,  FIG. 1  shows an example embodiment of the invention that may operate a WLAN  2  to share application data  71  that may include an ephemeris  70  of Global Positioning System (GPS) satellite  4  position data  72  by performing management-packet communication  8  between a station  10  near an access point  20 , and/or between a first and a second of the access points  20 , and/or between a first and a second of the stations  10 . In this specification, the term “connection-based communication” may be used to refer to traditional communication typically between an access point and a station. Such communications generally rely upon the station associating with the access point. The act of association may provide permission and/or establish a connection for the station to access and otherwise use a network connection though the access point. 
     Management-packet communication  8  of the application data  71  may not use typical connection-based communications. The station  10  may not need to connect to a nearby access point  20 . The transfer of the application data  71  requires no log-on, no authentication, no access permission and no need for access to the Internet. A station  10  passing close to the access point  20  suffices to transfer the ephemeris  70 . 
     Management-packet communication  8  may be supported by an integrated circuit  30  including a processor  50  configured to support the WLAN  2  and use a management frame  69 , such as a beacon frame  60  for management-packet communication  8 . The processor  50  may be configured to operate an application  51  based upon the application data  71 . The application  51  may be a form of GPS enabled navigator and/or use a GPS position. The integrated circuit  30  may be part of the access point  20  and/or of the station  10 . The processor  50  may be further configured to use an Information Element  62  in the beacon frame  60  to perform management-packet communication  8  the application data  71 , the availability of the application data, and/or the request for the application data. 
     The first access point  20  has received  6  the position data  72  for the GPS satellite  4  as shown in  FIG. 1 . The access point  20  may use and/or include a GPS receiver. In other situations, the access points  20  may be blocked from such receptions and may rely on one or more of the stations  10  receiving  6  the position data  72  for the GPS satellite  4  and to perform management-packet communication  8  of the position data  72  with them. In an alternative embodiment, the access point  20  may be connected to an alternative source of the application data  71 , such as a source of the ephemeris  70  available through the Internet. 
     The application data  71  may also include a quality estimate  74  that may indicate whether the ephemeris  70  and/or the position data  72  was directly received  6  from the GPS satellite  4 . The quality measure  74  may also indicate how many transfers have been made since the data was received  6  from the GPS satellite  4 . The quality estimate  74  may also indicate whether the original source of the GPS position data  72  and/or the ephemeris  70  may be from the Internet, possibly indicating the source on the Internet. 
     The application data  71  may include an estimate of the time in a local time zone and/or an estimate of a standard time such as Greenwich Mean Time and/or an estimate of a network time used in a WLAN and/or LAN. Similarly the application data  71  may include a location estimate that may or may not be derived from GPS position data  72  or the ephemeris  70 . 
     An example of a push approach to management-packet communication  8  is shown in  FIG. 1 , since the ephemeris  70  is always made available (i.e., “pushed”) though one or more beacon frames  60  without the necessity of a request. In other embodiments, the ephemeris  70  may be pushed by a probe request from a station  10  to the access point  20 . In yet other situations, when an ad hoc or peer to peer situation exists, there are no nearby access points  20 , and one of the stations  10  is temporarily acting to send the beacon  60 , that station  10  may push the application data  71 , and/or the ephemeris  70 , and/or the position data  72 . In contrast, a pull approach is illustrated in  FIG. 2 . 
       FIG. 2  shows a transaction diagram of the pull approach performing management-packet communication  8  as transactions through time  11  between an access point  20  and a station  10 . The station  10  may initiate a management-packet communication  8  by sending a probe request  66  to the access point  20 . The access point  20  may perform management-packet communication  8  by sending the ephemeris  70  to the station  10  in response to the request  66 . The request  66  may be sent in response to the access point  20  sending a beacon frame  60  including an availability  64  of the ephemeris  70  and/or the specific position data  72  for one or more of the GPS satellites  4 . In one embodiment, these transactions may occur when the station  10  notes that its position data  72  and/or ephemeris  70  for the GPS satellite  4  has aged, expired or may otherwise be inaccurate. 
     The availability information  64  of the ephemeris  70  may be indicated within a beacon frame  60 . The ephemeris  70  and/or the position data  72  may be sent in information elements  62  included in one or more of the beacon frames  60 . 
     In alternative embodiments, the pull approach may occur between two stations  10  or two access points  20  with a similar transaction diagram to that shown in  FIG. 2 . The transactions between two of the stations  10  may occur in an ad hoc or peer to peer situation when one of these stations is transmitting the beacons  60 . 
       FIG. 3  shows the WLAN  2  may be compatible with at least one wireless communication protocol  80  that may be compliant with a version of an Institute for Electrical and Electronic Engineers (IEEE) 802.11 standard 82. The wireless communications protocol  80  may include control frames and application data frames that may not used directly in management-packet based communication. The management-packet communications may use some or all of the management frames  69 , which may include, but are not limited to, versions of the beacon frame  60 , the probe request  66  and/or a probe response  68 . 
     Before proceeding, some background in the Open System Interconnection (OSI) model of communications is useful. Communications in the IEEE 802 family of standards are based upon the OSI model, which has seven layers, of which the following are relevant: the physical (second from the bottom) layer, the presentation (sixth) layer and the application (seventh and highest) layer. The physical layer typically deals with messaging conventions of the wireless communication protocol  80 . The presentation layer normally provides the communication context for the sharing of the application data  71  for the applications  51  on the application layer. Management-packet communication  8  essentially moves the sharing of the application data  71  down to the physical layer, below the level of connection-based communications. 
     To summarize some of the preceding discussion, management-packet communication  8  may be supported by the integrated circuit  30  including the processor  50  configured to support the WLAN  2  and the management-packet communication  8 . The integrated circuit  30  may be part of the access point  20  and/or of the station  10  as shown in  FIG. 1 . The processor  50  may be further configured to use the beacon frame  60  and/or its Information Element  62  for management-packet communication  8  of the application data  71 , the availability  64  of the application data, and/or the request  66  for the application data as shown in  FIGS. 1  and/or  2 . 
       FIG. 4  shows the processor  50  may include at least one instance of a finite state machine  52 , a computer  54  and/or a computer accessible memory  56  configured for access  55  by the computer  54  to retrieve a program system  90  to instruct the computer  54  to support management-packet communication  8 . This Figure also shows a computer readable memory  57  and/or a server  59  configured to communicate the program system  90  and/or an installation package  92  to the integrated circuit  30 . The installation package  92  instruct the computer  54  to install the program system  90  in the computer accessible memory  56  and/or to configure the finite state machine  52 . 
     As used herein, the computer  54  may include at least one instruction processor and at least one data processor, with at least one of the data processors instructed by at least one of the instruction processors to at least partly implement management-packet communication  8  using the program system  90 . These operations may be at least partly illustrated the program steps of  FIG. 5 . These program steps may reside in the computer accessible memory  56 , which may include volatile and/or non-volatile memory components. 
       FIG. 5  shows some details of the program system  90  instructing the processor  50  in terms that may disclose flow of control, state transitions and/or position data. These embodiments may include a program operation, or program thread, executing upon the computer  54  or states of the finite state machine  52 . Each of these program steps may at least partly support the operation to be performed. The operation of starting may involve entering a subroutine or a macroinstruction sequence in the computer or of a possibly initial state or condition of the finite state machine. The operation of termination may complete those operations, which may result in a subroutine return in the computer, or possibly return the finite state machine to a previous condition or state. 
       FIG. 5  shows the program system  90  may support management-packet communications  8  in terms of infrastructure messaging  130  and/or ad hoc messaging  132 . The infrastructure messaging  130  may be implemented based upon the management-packet communications  100  between the station  10  and the access point  20  of  FIGS. 1 and 2  and/or the management-packet communications  102  between two of the access points  20 . The ad hoc messaging  132  may be implemented based upon the management packet communication  104  between two of the stations  10 . 
     As used herein, ad hoc or peer to peer messaging  132  occurs when there is no access point  20  available to direct the WLAN  2  communications between those stations  10 . Most implementations of ad hoc messaging involve the stations  10  each temporarily acting as an access point  20  by sending the beacon frame  60 . This station  10  will be referred to as an access station. The other stations  10  may respond with probe requests  66  and the temporary access station  10  may respond to those probe requests  66 , possibly with the next beacon frame  60 , creating similar exchanges to those shown and discussed earlier regarding  FIGS. 1 and 2 . 
     The program system  90  may include at least one of the following: Program step  100  supporting management-packet communication  8  between at least one of the stations  10 , and at least one of the access points  20 . Program step  102  supporting management-packet communication  8  between two access points  20 . Program step  104  supporting management-packet communication  8  between two of the stations  10 . Any of these program steps may further support sharing the ephemeris  70  and/or the position data  72 . Support for management-packet communication  8  as found in at least one of these program steps may include management-packet communication  8  in the push mode illustrated in  FIG. 1  and/or management-packet communication  8  in the pull mode illustrated in  FIG. 2 . 
     The program system  90  may support operating the integrated circuit  30  of  FIG. 4  as part of the station  10  and/or support operating the integrated circuit  30  as part of the access point  20 . 
     The preceding embodiments provide examples and are not meant to constrain the scope of the following claims.