Patent Application
20080069068
As shown in the drawings for purposes of illustration, the invention is embodied in an apparatus and method for providing a client device of a wireless network with information of the quality of a link between the client device and the network, and information of at least one parameter of the wireless network. Providing the link and wireless network information allows the client device to make an intelligent decision of how (which access point, access node or gateway) to connect to the wireless network.
When a client device is attempting to associate with a network, the client device transmits a probe request. For example, the client device 254 transmits a probe request 232 which can be received, for example, by the access points 220, 222. In response to the probe request 232, each access point that receives the probe request 232 transmits a probe response that indicates that the access point received the probe request 232. For example, the access point 220 transmits a probe response 234, and the access point 222 transmits a probe response 236. Similarly, a second client device 256 can transmit a probe request 242. The probe request 232 can be received, for example, by the access points 220, 222, which respond with probe response 244 and 246.
Based on the probe responses 234, 236, 244, 246, the client devices 254, 256 select an access point to associate with. As previously mentioned, if the client devices receive multiple probe responses, the client devices may make a poor selection.
Intelligent Probe Responses
The probe responses 234, 236, 244, 246 include additional information that can aid the client devices 254, 256 in their selection of which access point to associate with. That is, the access points 220, 222 are configured so that the probe responses generated by the access points 220, 222 include information in addition to a standard probe response that aids the client devices in selecting an access point.
The additional information included within the probe response can be, for example, a receive signal strength of the probe requests. That is, the signal strength of the probe requests can be measured by a receiving access point. The receiving access point includes an indicator of the received signal strength indicator (RSSI) with the probe response. The client device is able thereby to gauge the quality of the link between the client device and the access point based on the RSSI. More specifically, the client device is able to gauge the quality of the link (uplink) directed from the client device to the access point. This additional link quality information can aid the client device in more properly selecting an access point.
The additional information can also include parameters of the network. Exemplary network parameters include a bandwidth of an upstream link of the access point, stability of the access point, or a latency of the access point. For the embodiment of
The additional network information can be appended to the probe response, or the additional network information can be used to modify the previously described RSSI. That is, the quality of the RSSI influences the client device selection. The additional network parameters can influence the client device selection by modifying the RSSI depending upon the degree of desirability of the client device associating with the access point based on the network parameter.
Wireless Network Path Quality Parameter
The probe response includes the receive signal strength indicator, but also includes a wireless network quality parameter. Exemplary embodiments of this parameter include a bandwidth of an upstream link of the access point, stability of the access point, or a latency of the access point.
The essential difference between the embodiment of
Wireless Mesh Network
The gateways 420, 422 can be wirelessly or wire connected to the wired network 410 through links 412, 414. The gateways 420, 422 can also be access nodes or access point in that the gateways 420, 422 can directly provide client devices 454, 456 with access to the wired network 410.
When the client devices 454, 456 are attempting to associate with a network, the client devices 454, 456 transmit probe requests 432, 442. All gateways and access node that receive the probe request can respond with a probe response indicating that they received the probe request, and are potential candidates for the client device to associate with. However, if the client device receives many probe responses, the client device can make a poor decision, causing the client device to associate with an inferior gateway, access node or access point.
As shown in
An embodiment of the probe response includes a quality indicator (for example, RSSI) of the link between the client device and the device transmitting the probe response. The probe response can also include at least one quality parameter of wireless network. Generally, the number of possible network quality parameters for the wireless mesh network of
The quality of the link can be determined, for example, by measuring the previously described received signal strength of the probe request. Wireless mesh network parameters, however, can also influence the desirability of one network device (gateways, access node or access point) over another network device. For example, data throughput, latency and stability of the device (gateway or access node) transmitting the probe response can also be useful in aiding a client device in selecting whether to associate with one device or another. The probe response of each device that receives a probe request can additionally include at least one network parameter of the device.
Mesh Network Quality Parameter
One example of a mesh network quality parameter is an indicator of a path quality of the access node to a gateway of the mesh network. As shown in
Another wireless network quality parameter that can be useful includes an indicator of a bandwidth of a backhaul connection. If the connecting device is a gateway, the backhaul is the connection between the gateway and the wired network. If the connecting device is an access node, the backhaul is the connection between the default gateway of the access node and the wired network. The backhaul connections 412, 414 of the gateways 420, 422 can be wired or wireless. This information, and the bandwidth of the backhaul connections 412, 414 can be included within the probe response
Mesh networks can include fixed and mobile access nodes. Mobile access nodes are typically less reliable because of the changing condition of their wireless links (upstream and/or downstream). Therefore, another useful mesh network quality parameter is an indicator of whether the access node is a mobile access node or a fixed access node.
Mesh networks include some form of latency between, for example, an access node of the mesh network and the corresponding default gateway. More specifically, the latency can be for the data path between the access node and its default gateway. The latency can vary form one access node to another. The latency of the access node can be determined by . . . Once the access node knows its latency, it can indicate the latency through a latency indicator, which can be include as or within the mesh network quality parameter.
Routing Selections
As previously described, the quality of an upstream path from an access node to a default gateway can be determined during routing selection by the access node. An embodiment of the mesh network includes gateways originating and broadcasting routing beacons at a predetermined rate (such as 4 beacons per second). Each first level access node (such as access nodes 430, 432) receive routing beacons from at least one of the gateways. By knowing the original rate in which the beacons are broadcast from the gateways, and the rate at which routing beacons are successfully received, the receiving access node can determined the persistence of successfully received routing beacons. An embodiment includes each first level access node selecting an upstream gateway based on a persistence of successfully received routing beacons.
Each first level access node can then rebroadcast the successfully received routing beacons. The rebroadcast beacons can include additional information allowing second level access nodes that receive the rebroadcast routing beacons to determine a routing path back to a gateway. The additional information can include identification (for example, an address) of the first level access node or a hop count (hop count indicates the number of wireless links an access node is from a gateway).
The mesh network can include any number of gateways and any number of access nodes. The number of wireless hops include within the wireless mesh network is not limited.
As previously stated, the persistence of received routing beacons can be used to select a routing path to a gateway. The persistence reflects that quality of the routing path to a gateway, and can be used to provide routing path quality within probe responses transmitted by each access node.
The routing path quality can be determined in both the downstream direction (away from the default gateway) and the upstream direction (towards the default gateway). The downstream quality can be determined by receiving routing beacons as described. The upstream quality can be determined by an upstream device (access node or gateway) receiving routing beacons from the access node, determining the persistence of successfully received beacons, and then including this information in the beacons that the upstream device broadcasts, and are received by the access node.
Wireless Mesh Network Path Quality Parameter
The probe response includes the receive signal strength indicator, but also includes a wireless mesh network quality parameter. As previously described, exemplary embodiments of this parameter include a routing path quality (downstream and/or upstream), backhaul bandwidth, latency, node type (fixed or mobile), and/or the number of wireless hops the access node is away from the default gateway. Other additional or alternate mesh networking parameters can be used as well.
The essential difference between the embodiment of
Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. The invention is limited only by the appended claims.
