Abstract:
A dual mode wireless device operations in a client mode and observes network congestion conditions. When the network congestion exceeds a threshold level, the dual mode wireless device changes to an access point mode and advertises itself to other clients, thereby reducing the network congestion level.

Description:
The present application claims priority of provisional patent application 61/408,239 filed Oct. 29, 2010. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a wireless device for use in WLAN environments. In particular, the invention relates to a dual mode device which switches between an AP mode and a client mode in IEEE 802.11 wireless networks. 
     BACKGROUND OF THE INVENTION 
       FIG. 1  shows a stadium with users of wireless devices associated with access points AP1  102 , AP2  104 , and AP3  106 . Each access point such as  104  is associated with a plurality of users  120 - 1 ,  120 - 2 , . . . ,  120 -N. The plurality of users with a particular access point AP2  104  is shown in  FIG. 2 . 
     OBJECTS OF THE INVENTION 
     A first object of the invention is a dual mode wireless device which switches from station mode to access point mode when certain network conditions are detected, such as congestion, number of stations associated with a particular access point, or reduction in data rate. 
     A second object of the invention is a dual mode wireless device which is capable of operation in either wireless access point infrastructure mode or wireless station mode. 
     SUMMARY OF THE INVENTION 
     The invention is a dual mode wireless device (known as LiteAP) for use in networks such as those described by the IEEE 802.11 series of wireless standards. The LiteAP device initializes in station mode, and may associate with an access point and send and receive wireless traffic through the access point. After operation in station mode, the dual mode LiteAP device may switch to access point mode upon detection of any of several threshold conditions, such as detection of a data rate reduction below a particular threshold, detection of a threshold number of active wireless stations, geographical or station location relative to other stations and access points, or any other throughput-related metric. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the plan view of a stadium with wireless stations and access points. 
         FIG. 2  shows a plurality of stations associated with an access point. 
         FIG. 3A  shows an access point with a dual mode device in station mode, and other stations. 
         FIG. 3B  shows an access point with a dual mode device in access point mode, and other stations. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to a multi-function wireless network device which can switch between client mode and access point (AP) mode in an 802.11 WLAN network using network congestion measurements, and without any user interaction. 
     802.11 WLAN is today the de-facto standard in wireless networking. However, in areas with large concentration of Wi-Fi users, the quality of connectivity tends to fall drastically. In crowded environments such as sports stadiums, there is often a gathering of several tens of thousand spectators, a sizeable fraction of who attempt to use the Wi-Fi access provided locally. 
     The present invention provides a special function device that can operate in station (client) and access point mode, and intelligently switch between these two modes. In a station mode the device connects to the infrastructure such as an access point for connectivity. This functionality is similar to other such standard clients. 
     In an access point mode the device acts as a repeater station for an infrastructure access point, and provides connectivity to other clients in the near geographical location of the dual mode device. The dual mode device will dynamically switch the mode of operation depending on number of users, traffic and QOS requirements. Dynamic switching will allow in designing the network topology by controlling the number of active AP&#39;s in a crowded environment. Using the present dual mode device dispersed in a dense network, the number of active AP&#39;s can be increased or decreased without impacting the number of installed infrastructure AP&#39;s. 
       FIG. 3A  shows a typical cell  350  populated by number of clients  301 ,  302 ,  303 ,  304 ,  321 ,  322 ,  323 ,  324 , and  325 , an infrastructure access point  104 , and a dual mode device in station mode STA-20  320 -STA. While one dual mode device  320 -STA is shown, any number of them may be present, and the cell  350  can have a combination of the dual mode device and standard clients along with multiple infrastructure access points. 
     Upon detection of network congestion by the dual mode device  320  in cell  350  of  FIG. 3A , the dual mode device  320 -STA remains associated to AP2  104  as a station via link  354  and advertises itself as an access point AP-20  320 -AP to stations  321 ,  322 ,  323 ,  234  and  325  as shown in  FIG. 3B . The AP functionality of dual mode device  320 -AP in access point mode will be a subset of standard access point and is known as LiteAP™. LiteAP  320 -AP can have the characteristics of a repeater, receiving packets from infrastructure AP2  104  over link  356  with the LiteAP  320 -AP operating as a station to infrastructure AP  104 , thereby extending the reach of AP2  104  by advertising beacons and connecting to local stations as their access point, and providing access point capabilities for the localized cell for stations  321 ,  322 ,  323 ,  235 , and  325 . This enables the dual mode device  320 -AP to force the remaining stations  321 ,  322 ,  323 ,  234 , or  325  in the cell to connect to LiteAP instead of the previous infrastructure AP  350  of  FIG. 3A . The LiteAP  320 -AP can also provide for buffering capabilities. This will help in reducing throughput requirements on a standard AP emerging from simultaneous connections to the same infrastructure AP. A LiteAP  320 -AP allows the introduction of other proprietary modes of transmission into a standard 802.11 environment without disrupting the existing infrastructure and network operation. 
     A metric measurement and threshold step provides metrics to switch one of the special devices into LiteAP mode. The switch to LiteAP mode allows for the creation of a smaller cell within the standard infrastructure cell. Several criteria may be used to form the metric, among which are: 
     1. The number of users in either a specific geographic or logical location. 
     2. The number of client connections on a standard infrastructure access point, as detected by the dual mode device examining traffic to that AP. 
     3. The amount of traffic between different clients and a standard infrastructure access point. 
     The operation of the device in client and AP mode is transparent to a user and is controlled based on intelligence in the infrastructure. The switching is controlled based on a variety of algorithms executing in the infrastructure through multiple such devices. 
     In one example of the invention, upon detection of a threshold condition, the dual mode station STA-20 converts from a client to an access point in repeater mode. 
     In another example of the invention, the dual mode device operates as an access point to local stations and as a station to the infrastructure AP, buffering packets from the infrastructure AP and then transmitting those packets to stations which associate with the dual mode device.