Abstract:
An embodiment of the invention involves a method for selecting and maintaining wireless communications for wireless mesh networks between tier-2 and tier-3 nodes. The method comprises a first operation of receiving channel information from a first wireless node operating as an access point. The channel information includes each channel number used by one or more wireless nodes that are detected by the first wireless node to be operating within a signal coverage area of the first wireless node. Then, an active scan is conducted on a frequency spectrum for wireless signals based on the channel information. Such scanning is accomplished by initially scanning frequencies of each channel number used by the one or more wireless nodes. After the scanning, a determination is made whether to (i) maintain wireless communications with the first wireless node or (ii) establish new wireless communications with a new wireless node (AP). Other embodiments are described and claimed.

Description:
FIELD 
     The invention relates generally to the field of wireless device connectivity. More particularly, one or more of the embodiments of the invention relate to an apparatus and method for managing access point (AP) selection and varying the periodicity in monitoring communications with the AP based at least in part on the longevity of such communications. 
     BACKGROUND 
     A wireless network can provide a flexible data communication system that can either replace or extend a wired network. Using radio frequency (RF) technology, wireless networks transmit and receive data over the air through walls, ceilings and even cement structures without wired cabling. For example, a wireless local area network (WLAN) provides all the features and benefits of traditional LAN technology, such as Ethernet and Token Ring, but without the limitations of being tethered together by a cable. This provides greater freedom and increased flexibility. 
     Currently, a wireless network operating in accordance with the Institute of Electrical and Electronic Engineers (IEEE) 802.11 Standard (e.g., IEEE Std. 802.11a/b/g/n) may operate in infrastructure mode (infra-mode) or ad hoc mode. As of today, most installed wireless networks are configured and operate in infra-mode where one or more access points (APs) are configured as interfaces for a wired distribution network (e.g., Ethernet). In infra-mode, mobile devices with wireless connectivity (e.g., laptop computer with a radio network interface card “NIC”) are able to establish communications and associate with the AP, and thus, the users of these devices are able to access content within servers connected to the wired network. 
     As an optional feature, however, the IEEE 802.11 Standard specifies ad hoc mode, which allows the radio NIC within each wireless device to operate in an independent basic service set (IBSS) network configuration. Hence, the wireless devices perform peer-to-peer communications with each other instead of utilizing the AP for supporting such wireless communications. 
     One type of ad hoc network is referred to as a mesh network, which allows for continuous connections and reconfiguration around broken or blocked paths by “hopping” from device to another device until the destination is reached. Mesh networks differ from other networks in that the devices can all connect to each other via multiple hops without infrastructure (e.g., wired APs), and these devices can be mobile or stationary. Related to mesh networks, mobile ad-hoc networks (MANETs) are self-configuring networks of mobile routers, where the routers are free to relocate. 
     One of the primary disadvantages of conventional mesh networks is their inability to effectively manage connectivity with mobile devices by scanning wireless channels for improved AP communications. Effective management may be measured through faster AP selection by the mobile devices along with an improved possibility of finding a neighboring AP with better signal quality. Unfortunately, the conventional AP selection process does not effectively account for periods of intermittent improved signal quality, which results in unnecessary and unwanted roaming to occur. Hence, there is a need for a mechanism to overcome these disadvantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which: 
         FIG. 1  is a block diagram illustrating an embodiment of a three-tier wireless ad hoc mesh network. 
         FIG. 2A  is a block diagram illustrating a first embodiment of a tier-2 node within the network of  FIG. 1 . 
         FIG. 2B  is a block diagram illustrating a second embodiment of a tier-2 node within the network of  FIG. 1 . 
         FIG. 3  is a block diagram illustrating an embodiment of a tier-3 node within the network of  FIG. 1 . 
         FIG. 4  illustrates an exemplary embodiment of an AP beacon message packet format. 
         FIG. 5A  is a block diagram illustrating an embodiment of a wireless mesh network protocol architecture for a tier-2 node. 
         FIG. 5B  is a block diagram illustrating an embodiment of a wireless network protocol architecture for a tier-3 node. 
         FIG. 6  illustrates an exemplary embodiment of the operations of the AP selection logic of the active scan logic of  FIG. 5B . 
         FIG. 7  illustrates a more detailed embodiment of the operations of the AP selection logic of the active scan logic of  FIG. 5B . 
         FIG. 8  illustrates an exemplary embodiment of the operations by the AP quality monitoring logic implemented within the tier- 3  node of  FIG. 5B . 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent; however, to one skilled in the art that present invention may be practiced without some of these specific details. In addition, the following description provides examples, and the accompanying drawings show various examples for the purposes of illustration. However, these examples should not be construed in a limiting sense as they are merely intended to provide examples of embodiments of the invention rather than to provide an exhaustive list of all possible implementations. For instance, the invention may be applicable for networks generally operating in accordance with any IEEE 802.11 Standard (e.g. IEEE 802.11 a/b/g/n/ . . . ) as well as other standards (e.g., HiperLAN) or any proprietary communication protocols supporting wireless communications, including proprietary communication protocols that are substantially based on well-established standards. In some instances, well-known structures and devices are not shown in block diagram form in order to avoid obscuring the details of the disclosed features of various described embodiments 
     System Architecture 
     In the following description, certain terminology is used to describe certain features of the invention and well-known structures and devices may not be shown or described in detail in order to avoid obscuring the details of the disclosed features of various described embodiments. 
     The term “node” is generally defined as an electronic device with data processing capability and perhaps wireless communication capabilities. An ad hoc network may be formulated as “OEM-specific,” meaning that access is restricted to those wireless nodes that are manufactured and/or endorsed and/or sold by the same entity or a group of entities. For instance, an example of an OEM-specific wireless mesh network (WMN) is a network that comprises a Sony® BRAVIA® digital television in communications with a Sony® Playstation® game console, a Sony® VAIO® computer, a Sony® handheld device, or any of Sony® based products with networking capability. 
     Herein, there are two general types of nodes. A first type is a “mesh node” that is specifically adapted to join and become a member of an OEM-specific ad hoc network such as an OEM-specific WMN. The second type is a “non-mesh node” that is only able gain access to an OEM-specific WMN indirectly through a mesh node. Such access may be through wireless or wired communications. For this description, the term “node” shall constitute either a “mesh” node or “non-mesh” node and the terms “WMN” or “WM network” shall constitute any type of ad hoc network. 
     The terms “logic” and “logic unit” are generally defined as hardware and/or software configured to perform one or more functions. One example of a certain type of logic is a radio network interface card (NIC) that features a wireless chipset being one or more integrated circuits operating to transmit and/or receive signals in order to access a wireless network. “Software” is generally described as a series of executable instructions in the form of an application, an applet, or even a routine. The software may be stored in any type of machine readable medium such as a programmable electronic circuit, a semiconductor memory device such as volatile memory (e.g., random access memory, etc.) and/or non-volatile memory such as any type of read-only memory (ROM) or flash memory, a portable storage medium (e.g., USB drive, optical disc, digital tape), or the like. 
     The term “message” represents information configured for transmission over a network. One type of message is a frame that is generally defined as a group of bits of information collectively operating as a single data unit. The term “content” represents video, audio, images, data, or any combination thereof. 
     Referring to  FIG. 1 , an exemplary embodiment of a multi-tier wireless mesh network  100  is described. Multi-tier wireless mesh network (hereinafter referred to as “WMN” or “WM network”)  100  comprises a collection of nodes that operate as a decentralized, wireless mesh network with multiple (M≧1) sub-networks  110   1 - 110   M  (hereinafter singularly referred to as “tiers”). Mostly every node of WM network  100  is configured to forward data to other nodes and is assigned to a specific tier based on its performance capabilities and power constraints. The assignment of a node to a particular tier is a decision at least partially based on performance capabilities of the node, whereas routing decisions are made by the nodes based on the network connectivity and the ability to forward data by that particular node. 
     For instance, one embodiment of WM network  100  features a hierarchical architecture comprising a plurality of tiers (e.g., 3 tiers) that are assigned based on the capabilities of the OEM-specific node. A first tier (“tier-1”)  110   1  is responsible for establishing and controlling access to an external network such as the Internet. For example, first tier  110   1  may resemble a traditional Internet connection via a cable or direct subscriber line (DSL) connection or 3G/WiMax/Outdoor mesh. As illustrated, first tier  110   1  comprises a first node  120 , which is commonly referred to as a “gateway node.” Gateway node  120  may include, but is not limited or restricted to a cable or DSL modem, a wireless router or bridge, and the like. Although not shown, multiple gateway nodes may be present within WM network  100  in order to provide multiple communication paths to external network(s). 
     A second tier (“tier-2”)  110   2  of WM network  100  may represent a wireless network backhaul that interconnects various stationary (fixed-location) OEM-specific wireless nodes adapted for communicating over a wireless communication medium such as, for example, radio frequency (RF) waves. As described herein, a “tier-2 node” includes, but is not limited or restricted to: a flat-panel television  130 ,  131 , and  132 , a gaming console  140 , computer  150 , or any other electronic device with wireless capability that is usually stationary and electrically coupled to an alternating current (AC) power outlet. Hence, tier-2 nodes usually are not subject to power constraints that are present in tier-3 nodes where power usage is minimized to extend battery life between recharges. 
     As shown, computer  150  is adapted to operate in two modes. As a wireless mesh node, it can wirelessly communicate with other mesh nodes using the appropriate mesh protocol and be configured by users to join one existing WMN. As a non-mesh node, it can communicate with wireless non-mesh nodes with Ethernet and/or Wi-Fi network cards that are produced by a different manufacturer, to allow them accessing WM network  100  using the standard IEEE 802.11 or Ethernet protocol. Effectively, it enables a non-mesh node access to contents and resources on WM network  100 . For instance, flat-panel television  131  may use its Wi-Fi radio operating in accordance with a selected communication protocol (e.g., IEEE 802.11a/b/g/n; HiperLAN, etc.) to associate with computer  150  and effectively access WM network  100 . Also, computer  150  allows wired non-mesh nodes to associate with and join WM network  100 . Although not shown, a wired non-mesh node (e.g., facsimile machine) can connect to computer  150  by using a standard Ethernet cable. In both cases, such connectivity may be accomplished without any additional hardware or software modification. 
     In order to maintain a simple architecture and to ease roaming, it is contemplated that tier-2 nodes, when operating as APs, use the same network identification (SSID) and, in some cases, the same security profile (e.g., a saved group of security settings such as Wi-Fi Protected Access “WPA”, Temporal Key Integrity Protocol “TKIP”, etc.). This greatly assists in AP discovery when a tier-3 node runs an active scan to discover APs that provide better signal quality for that node. The result of the active scan can be quickly processed by ignoring networks that have a different SSID and perhaps different security profiles. 
     Referring still to  FIG. 1 , a third tier (“tier-3”)  110   3  of WM network  100  may include links between a node belonging to second tier  110   2  and one or more tier-3 nodes ( 160 ,  162 ,  164 ,  166 ,  168  &amp;  169 ). A “tier-3 node” may be any battery powered electronics device with wireless connectivity including, but not limited or restricted to a laptop computer, portable handheld device (e.g., personal digital assistant, ultra mobile device, cellular phone, portable media player, wireless camera, remote control, etc.) or any non-stationary consumer electronics devices. Since tier-3 nodes normally have resource constraints (e.g., limited power supplies, limited processing speeds, limited memory, etc.), third tier  110   3  may provide reduced network services. In one embodiment, tier-3 nodes of WM network  100  may act as a slave or child connecting directly to a tier-2 node, which may further limit their functionality within WM network  100 . 
     Since the traffic on backhaul  170  may include high-definition (HD) video, audio clips and video clips, as well as user data, radio NICs may be incorporated within some of the stationary nodes of the WM network  100 . For example, by multiplexing a flow of compressed HD video, multiple Internet video sessions, multiple audio/video sessions and some intermittent http data traffic, the load on backhaul link  170  could reach approximately 60 megabits per second for TCP/UDP type traffic, which may require at least  100  megabits per second of raw radio support considering media access control (MAC) layer efficiency. According to this example, the tier-2 nodes might require an IEEE 802.11n type radio (e.g., at 5 GHz band) to meet such bandwidth requirements. 
     According to one embodiment of the invention, tier-2 (acting as AP) nodes follow a procedure to decide on non-overlapping channels to use for their infra-mode activity. According to this procedure, every tier-2 (AP) node has information regarding which channel its neighboring tier-2 (AP) node is using. According to one embodiment of this invention, tier-2 nodes are adapted to send this channel information to their tier-3 client nodes in the reserved fields of the beacon (other by other means specific to the implementation) to assist in roaming, thereby ensuring better overall tier-3 network connectivity within the WM network. 
     Referring to  FIG. 2A , a first exemplary embodiment of a tier-2 node, such as tier-2 node  132  for example, is shown. Herein, tier-2 node  132  comprises an embedded wireless network chipset  200  in communication with one or more processors  210 , memory  220 , a communications interface  230  and a user interface (UI)  250 . According to this embodiment, tier-2 node  132  may be adapted to operate in two modes (ad hoc &amp; infrastructure) in a Time Division Multiple Access (TDMA) fashion using the same radio logic unit  235  deployed within communication interface  230 . Radio logic unit  235  is controlled by processor  210  or dedicated circuitry (not shown) to tune and receive incoming wireless signals on a particular channel via one or more antennas  240   1 - 240   N  (N≧1) and to transmit outgoing wireless signals to other nodes over that particular channel. Stored within memory  220 , candidate scan channel information  245 , being an aggregate of wireless channel information associated with tier-2 nodes operating as access points (APs) in the same signal coverage area as tier-2 node  132  (generally referred to as “neighboring tier-2 node(s)”), is provided to tier-3 node(s) in order to assist in tier-2 (AP) selection. This wireless channel information, which includes at least data representing the wireless channel utilized by a particular neighboring tier-2 node, is sent to tier-3 node as part of a non-unicast message such as within an AP beacon transmitted by tier-2 node  132 . 
     Referring now to  FIG. 2B , a second exemplary embodiment of tier-2 node  132  is adapted to store candidate scan channels  245  is shown. Herein, tier-2 node  132  comprises a first radio logic unit  250  and a second radio logic unit  260 . According to one embodiment of the invention, each of the first and second radio logic units  250  and  260  comprises either a single-band or a dual-band Wi-Fi radio which may operate on different channels from each other to avoid interference. First radio logic unit  250  and second radio logic unit  260  receive/transmit messages via antennas  240   1  and  240   2 , respectively. Herein, first logic unit  250  enables tier-2 node  132  to operate in an ad hoc mode and establish communications with ad hoc networks while second logic unit  260  enables tier-2 node  132  to operate in infra-mode by transmitting beacons and conducting other operations as an AP in its communications with various wireless tier-3 nodes. 
     Referring to  FIG. 3 , an exemplary embodiment of a tier-3 node, such as tier-3 node  162  for example, is shown. Herein, tier-3 node  162  comprises an embedded wireless network chipset  300  that is coupled to one or more processors  310 , memory  320 , a communications interface  330  and a user interface (UI)  350 . According to this embodiment, tier-3 node  162  (due to its limited resources) is adapted to operate in infra-mode only. Radio logic unit  335  is controlled by processor  310  or dedicated circuitry (not shown) to tune and receive incoming wireless signals on a particular channel via one or more antennas  340   1 - 340   R  (R≧1) and to transmit outgoing wireless signals to other nodes over that particular channel. 
     Herein, processor  310  executes active scan logic  360  that is stored in memory  320  while tier-3 node  162  is operating in infra-mode. Of course, it is contemplated that active scan logic  360  may be deployed as firmware or hardware within tier-3 node  162 . For instance, as shown by dashed lines in  FIG. 3 , active scan logic  360  may be implemented as a programmable circuit in communication with chipset  300  in lieu of an executable in memory  320 . Active scan logic  360  comprises AP selection logic  370  and AP quality monitoring logic  380 . 
     Referring to  FIGS. 1 and 3 , typically, tier-3 node  162  will be within the coverage range of more than one tier-2 (AP) node. Therefore, tier-3 node  162  will have more than one AP to select for association and connectivity to WM network  100 . Since wireless signal conditions change due to device mobility or environmental changes, tier-3 node  162  periodically monitors its wireless connection with a current tier-2 (AP) node as well as proactively evaluates the availability and signal quality of neighboring tier-2 (AP) nodes. This monitoring process may involve measuring and analyzing certain parameters such as link quality (e.g., signal-to-noise ratio “SNR”), PHY bit rate, transmission/packet error rate, and lost AP beacons. If the result of this analysis indicates poor connectivity, the tier-3 node  162  would initiate an active scan using tier-2 specific AP SSID over different wireless channels in order to evaluate potential connections with the neighboring tier-2 (AP) nodes and select a new tier-2 (AP) node to associate with before the current wireless connection degrades to an unacceptable level. 
     According to one embodiment of the invention, as described below in further detail, the tier-2 (AP) node (e.g., flat panel television  132 ), which is currently associated by tier-3 node  162 , is configured to provide channel information for its neighboring tier-2 nodes (e.g., gaming console  140 ). More specifically, this channel information is placed within one or more reserved fields within an AP beacon. AP selection logic  370  of tier-3 node  162  extracts the channel information in order to expedite the re-scan process. In particular, tier-3 node  162  initially scans those wireless channels used by the neighboring tier-2 (AP) nodes such as game console  140 , which generally increases the overall speed of the active scan process because the possibility of finding a neighboring tier-2 (AP) node with better signal quality improves if the channels occupied by the neighboring tier-2 nodes are scanned first. The active scan process is adapted to gather information concerning the signal strength received from the neighboring tier-2 (AP) nodes. With this information, tier-3 node  162  can choose whether to stay connected to the current tier-2 node (e.g., node  132 ) or disconnect and associate with a new tier-2 (AP) node such as gaming control  140 . 
     Referring still to  FIGS. 1 and 3 , AP quality monitoring logic  380  controls the operations of tier-3 node  162  by altering the frequency in monitoring its wireless connections so that new connections are monitored more frequently than older, established connections. The monitoring time period, namely the cycle time between starting and restarting an active scan process, is shorter in duration for newly established connections than for prior connections perhaps in place for hours or days beforehand. Over time, the monitoring time period is increased until it reaches a predetermined periodic value. Thus, AP quality monitoring logic  380  is adapted to handle errand roaming conditions by prompting the tier-3 node  162  to re-associate with its former tier-2 node or immediately begin to associate with a new tier-2 node if problems with a new connection immediately develop. 
     Referring back to  FIG. 1 , flat panel television  132  is adapted to communicate with other tier-2 nodes (e.g., computer  150 , gaming console  140 , flat panel television  131 ) and that is already part of WM network  100 . When operating as an AP, during transmission of some or all of its beacons, flat panel television  132  includes wireless channel information associated with its neighboring tier-2 nodes. For instance, as shown in  FIG. 4 , AP beacon  400  comprises a media access control (MAC) header  420 , a frame body  440  and a frame check sequence (FCS)  460 . FCS  460  is used for error detection in the transmission of the message. 
     MAC header  420  comprises a destination address (DA) and a source address (SA). The destination address identifies that AP beacon is a broadcast message. It is contemplated that MAC header  420  may include one or more reserved fields that, according to this embodiment, may be used to contain wireless channel information concerning neighboring tier-2 nodes of the source tier-2 node using AP beacon  400 . Alternatively, the wireless channel information may be contained in a reserved element  450 , which is a portion of a capability information field  445  of frame body  440 . The specific details of how the wireless channel information is exchanged between tier-2 &amp; tier-3 nodes is not discussed herein since it can vary from system to system. SSID element  455  indicates the identity of the WM network featuring the tier-2 node. 
     As representatively shown in  FIG. 5A , in the protocol architecture  500  for a tier-2 node, logic associated with wireless mesh network (“WMN”) functionality  530  are placed between MAC layer  520  and network (IP) layer  540  to provide a solution that is independent of the higher OSI layers deployed and can be more easily reconfigured. Hence, WMN layer  530  generally constitutes an “OSI layer 2.5” solution for the tier-2 node. The placement of WMN layer  530  provides enhanced functionality that is transparent to both lower and higher OSI layers. 
     According to one embodiment of the invention, WMN layer  530  can perform WMN configuration such as auto-channel selection  525  for example, where non-overlapping channels are determined to be available and selected during ad hoc mode based on analysis of a number of parameters. These parameters may include, but are not limited or restricted to the number of non-overlapping channels associated with the particular communication standard supported by the WM network (“N c ”) along with parameters specific to this particular node and the neighboring nodes: (1) the network degree (e.g., a count of the number of neighboring node for a particular node, “N d ”); (2) the MAC address of the node (“M addr ”); (3) the number of iterations of the channel selection process that the particular node has undergone to select its current channel (“iCount”). Regardless of the channel selection process chosen, each tier-2 node retains and maintains the channel(s) used by its neighboring nodes for channel selection and for subsequent transmission to its tier-3 (client) nodes for roaming determinations. 
     As representatively shown in  FIG. 5B , in the protocol architecture  550  for a tier-3 node, logic associated with wireless mesh network (“WMN”) functionality  580  are placed between MAC layer  570  and network (IP) layer  590  to provide a solution that is independent of the higher OSI layers deployed and can be more easily reconfigured (e.g., an “OSI layer 2.5” layer). The placement of WMN layer  580  provides enhanced functionality that is transparent to both lower and higher OSI layers associated with the tier-3 node. 
     In one embodiment, WMN layer  580  can perform WMN (infra-mode) functions such as AP selection  370  and/or AP quality monitoring  380  for example. According to this embodiment of the invention, in general, active scan logic  360  is adapted to control the broadcast or multicast of wireless channel information for neighboring tier-2 (AP) nodes that are within its coverage range (AP selection logic  370 ). This information will assist in the scanning process with a notable improvement in locating a neighboring tier-2 (AP) node with better signal quality than provided by the current tier-2 (AP) node. Also, active scan logic  360  alters the frequency in monitoring connectivity with a tier-2 node by monitoring new connections more frequently than older established connections (AP quality monitoring logic  380 ). 
     Referring to  FIG. 6 , an exemplary embodiment of the operations of the AP selection logic, which is part of the active scan logic implemented within a node (e.g., tier-3 node), is shown. Initially, wireless connectivity with the current tier-2 (AP) node is monitored (item  600 ). This monitoring involves the measurement and analysis of parameters associated with the current tier-2 (AP) node (item  610 ). For instance, as an example, the tier-3 node may measure the signal-to-noise ratio (SNR) observed at a tier-3 receiver for signals from the current tier-2 (AP) node. Other parameters may include, but are not limited or restricted to the Physical Layer (PHY) bit rate used by the transmitter, the transmission/packet error rate, or the like. 
     If the measured parameters exceed a predetermined threshold (e.g., these parameters are lower or higher than the threshold), an active scan process is performed by the tier-3 node using the same SSID of the current tier-2 (AP) node (items  620  &amp;  630 ). In other words, the tier-3 node begins to scan for other tier-2 nodes having the same SSID (i.e. mesh network name) and perhaps the same security profile. During the active scan process, the client tier-3 node is able to determine and compare the signal strength of other tier-2 node(s) with that of its current associated tier-2 node to make a decision on whether to switch or continue with the current association. Thereafter, based on the scanned results, a decision is made whether the tier-3 node is to remain connected with the current tier-2 (AP) node (item  640 ). This decision may be made based on the signal strength measured from a neighboring tier-2 node, a greater bit rate used and supported by the neighboring tier-2 node, a lesser transmission/packet error rate, or the like. In the event that a better connection can be established with the neighboring tier-2 (AP) node, the tier-3 node disconnects from the current tier-2 (AP) node and associates with the new tier-2 (AP) node (item  650 ). Otherwise, the tier-3 node maintains its wireless connection with the current tier-2 (AP) node. 
     Referring now  FIG. 7 , a more detailed embodiment of the operations of the AP selection logic is shown. According with this embodiment, the current tier-2 node transmits a non-unicast message (e.g., an AP beacon), which is received by the tier-3 node. Information pertaining to the wireless channel(s) utilized by the neighboring node(s) for current tier-2 node is extracted from the AP beacon (item  700 ). In other words, for this embodiment of the invention, the AP beacon is configured to include wireless channel information concerning neighboring tier-2 (AP) node(s). In the alternative, it is contemplated that the wireless channel information may be transmitted separately from the AP beacon, in-band or out-of-band. 
     For instance, as an illustrative example, the current tier-2 (AP) node may be configured to operate on a first wireless channel (ch 1 ) of a set of three non-overlapping channels (ch 1 , ch 6 , ch 11 ) in accordance with a proprietary communication protocol that is based on the IEEE 802.11(b) Standard. However, a first neighboring tier-2 (AP) node is operating on a second channel (ch 6 ). This information about the first neighboring tier-2 operating on the second channel (ch 6 ) is placed within the AP beacon from the current tier-2 (AP) node. Based on this wireless channel information, the tier-3 node may initially scan the second channel (ch 6 ) before proceeding to scan a third channel (ch 11 ). This scan may involve periodically monitoring wireless signals received on the second channel (when the node is idle) or initiating one or more messages and measuring the signal quality from responses to these messages. For instance, the tier-3 node may transmit a query message (e.g., a Probe Request message) over the second wireless channel (ch 6 ) as shown in item  710 . If a Probe Response message from the neighboring tier-2 (AP) node is received in a timely manner by the tier-3 node, the link quality (SNR) is measured (items  720  &amp;  730 ). Thereafter, additional Probe Request messages may be produced for any additional channels identified in the AP beacon until all of the channels associated with the neighboring nodes have been queried (items  740  &amp;  750 ). 
     In the event that all of the wireless channels identified in the AP beacon have been scanned (item  760 ) or if, in response to the Probe Request message, a corresponding Probe Response message is not received in a timely manner (item  770 ), the tier-3 node continues to conduct an active scan for all of the remaining channels supported by the network type (item  780 ). 
     Referring now to  FIG. 8 , an exemplary embodiment of the operations by the AP quality monitoring logic implemented within the tier-3 node is shown. Herein, parameters that are used to establish the monitoring time period (cycle) are initialized (items  800 ). For instance, a count value is set to “1”. A starting time period (           ) is set to a first value and an incremental time period (         ) is set to a second value that may differ from the first value. Thereafter, the tier-3 node monitors the wireless connection with the current tier-2 (AP) node (item  810 ). This monitoring involves the measurement and analysis of parameters such as signal-to-noise ratio (SNR), beacon loss, transmission quality, packet loss and the like.
     If the measured parameters exceed a predetermined threshold (e.g., parameter are lower than prescribed threshold minimums or higher than prescribed threshold maximums), the tier-3 node performs an active scan process on different channels using the same SSID of the current tier-2 (AP) node and perhaps its security profile as shown in items  820  and  830 . The tier-3 node selects the tier-2 (AP) node with the best level of signal quality (item  840 ). 
     If the current tier-2 (AP) node remains the same, as shown in items  850  and  860 , the monitoring time period (m) is increased by an incremental value based on the first and second values (e.g., m=           *           i ) and the count value (i) being incremented. If the previous tier-2 (AP) node is not the same as the new tier-2 (AP) node, this denotes a new association and requires the monitoring time period to be initialized again by setting the count value to zero and the monitoring time period to           (item  870 ) during continued operations of the new tier-2 node in infra-mode (item  875 ). Where the computed monitoring time period (m) would be greater than or equal to a predetermined periodicity T, the monitoring time period remains at T (m=T) as shown in items  880  and  890 . However, if the computed monitoring time period (m) is less than the predetermined periodicity (T), the monitoring continues with the computed monitoring time period.
     Therefore, after each monitoring time period elapses, the tier-3 node monitors AP signal quality and performs active scanning as needed (item  895 ). 
     Having disclosed exemplary embodiments and the best mode, modifications and variations may be made to the disclosed embodiments while remaining within the scope of the embodiments of the invention as defined by the following claims.