Abstract: A method and system for measuring the time-of-flight (TOF) of a radio signal is described herein. According to various implementations, the system uses multiple antennas, each of which receives direct path radio signals and reflected radio signals. In various implementations, the system sends a sequence of bursts that are detected using a cross correlation detector. The receiver steers antenna nulls to a different angles for each burst and measures the TOF at each angle. The system then calculates the minimum correlation peak from all measurements, and treats that correlation peak as the true, direct path TOF measurement.

Abstract: A system and method which enables access points in a wireless ad-hoc communications network to effectively and efficiently determine the approximate location of a mobile node without performing a broadcast flood. The system and method enables a message to be efficiently communicated from an access point of the network, which provides access to a portion of the network or access to another network, to a wireless mobile node in the network. The system and method employ the operations of determining the access point with which the wireless mobile node is affiliated, storing information in a routing table at the affiliated access point pertaining to a routing path from the affiliated access point to the wireless mobile node, and updating the routing path when the wireless mobile node moves by a certain amount. The wireless mobile node can provide this routing path information to the affiliated access point in data packets sent to the affiliated access point.

Abstract: A method and apparatus for sending multicast packets from a first node to a plurality of nodes in a wireless communication system is disclosed. The method and apparatus comprise creating a neighbor list identifying a type of node for each neighboring node in the wireless communication network and sending a multicast request from the first node having a common type to a second node having a home type. Then, receiving the multicast request at the second node so that the second node can create a multicast packet from the multicast request and sending the multicast packet by the second node to the plurality of nodes in the wireless communication system.

Abstract: A system and method for locating optimal routes between source and destination nodes in a communications network, in particular, a wireless ad-hoc communications network by employing a link reliability algorithm that estimates the reliability of links between nodes using a prediction mechanism and a variable-weight filter. The prediction can be based on signal strength, signal-to-noise ratio or any statistic collected at the physical layer that is deemed representative of the quality of a link, and the weighting filter adjusts the predicted value based on the traffic conditions (e.g., idle, light traffic, moderate traffic or heavy traffic) being experienced by the nodes whose link quality is being estimated.

Abstract: A system and method for decreasing the route convergence time in a wireless communication network, such as a wireless ad-hoc peer-to-peer network, by finding an alternate route if the nodes anticipate weakening or breakage of a route currently in use. The system and method which enables reactive routing protocols to find optimal routes between nodes in these types of networks when those routes cannot otherwise be found in certain conditions. The system and method thus decrease the route convergence time, provide an effective and efficient way to find optimal routes, and improve overall performance of the network with regard to throughput, delay, packet completion rate and other factors.

Abstract: The present invention relates to a system and method for deploying devices, such as routers (107) and mobile nodes (102) or tags, that communicate in a wireless multihopping ad-hoc communication network (100), that enables a monitoring system such as a dispatcher (212) to create a reference system to identify the location of each device. The system and method thus allows for prompt identification of the locations of persons or items, particularly firefighters and other persons operating in hazardous environments, to expedite rescue efforts.

Abstract: Methods for delivery of multicast packets in a wireless communication system are disclosed. The methods comprise transmitting a contention free period initiation signal from an access point to the station, transmitting broadcast packets from the access point to the station, transmitting multicast packets from the access point to the station and holding the multicast packets in storage after the transmission, transmitting a contention free period end signal from the access point to the station, determining if a negative acknowledgement message has been received, retransmitting the multicast packets in response to receiving a negative acknowledgment message, and eliminating the multicast packets at a next beacon interval.

Abstract: A system and method for supporting multicast in highly dynamic wireless multi-hop networks, such as ad-hoc networks, with good scalability. The system and method provide a multicast routing algorithm to work in wireless ad-hoc networks without any fixed infrastructure nodes present. In doing so, the system and method provide a technique to build a multicast source specific tree on demand, while using a core source node to limit routing overhead. The system and method further provide a repair process to reduce the latency of discovery of topology change, employ a node sequence number mechanism to differentiate between upstream nodes and downstream nodes on the multicast tree in the repair process, and provide an active joining process to reduce the latency of discovery of membership change.

Abstract: A method and system for routing data in a wireless network (400) that enables all nodes (106, 402, 404, 406, 408) to find routes to each other even if the nodes (106, 402, 404, 406, 408) are non-meshed which are incapable of operating as a router to route packets received from other nodes (106, 402, 404, 406, 408), and for associating and reassociating the non-meshed and meshed nodes with other meshed nodes (106, 402, 404, 406, 408). The non-meshed nodes (STA 13-STA 15) request association with one of the meshed nodes (AP5) which are capable of performing packet routing, to request that the meshed node (AP5) with which the non-meshed node (STA 13) is associating operate as a proxy node to route packets between the associated non-meshed node (STA 13) and other meshed or non-meshed nodes (106, 402, 404, 406, 408).

Abstract: The present invention allows a single access point (“AP”; 100) to support a plurality of devices (102, 104) operating on different frequency bands. During a first period of time, the AP initiates a contention free period at a first frequency. The AP switches from the first frequency to a second frequency, and communicates with devices operating at the second frequency. Periodically during the first period of time, the AP temporarily ceases communication with devices operating at the second frequency to initiate a contention free period at the second frequency, switch from the second frequency to the first frequency, initiate another contention free period at the first frequency, and switch from the first frequency back to the second frequency.

Abstract: A method and system for wireless data transmission between at least three stations use multiple frequency bands for simultaneous channel communications. The method includes transmitting a Request To Send (RTS) packet from a first station to an intermediate second station over a first frequency band. Two Clear To Send (CTS) packets, which CTS packets include transmission timing information, are then transmitted from the second station simultaneously both to the first station and to a third station. The CTS packet sent to the first station is transmitted over the first frequency band and the CTS packet sent to the third station is transmitted over a second frequency band. A data packet from the first station is then transmitted to the second station. The third station suspends, based on the transmission timing information included in the CTS packets, any unicast transmission to the second station during the transmission of the data packet from the first station to the second station.

Abstract: The present invention provides a bandwidth efficient system and method of measuring the range between nodes (102, 106, 107) in a wireless communications network (100) with one-way data transfer, where each node (102, 106, 107) periodically transmits a message that contains information regarding neighboring nodes (102, 106, 107) from which any prior messages have been received by the transmitting node (102, 106, 107). A node (102, 106, 107) receives the messages transmitted from neighboring nodes (102, 106, 107) in the network (100), and records the times of arrival of the received messages. The node (102, 106, 107) receiving those messages can thus determine the respective distances between itself and the neighboring nodes (102, 106, 107) based on the respective time of arrivals of the received messages and the respective information included in the respective messages.

Abstract: A system and method for enabling an ad-hoc communication network to maintain connectivity with the mobile nodes in the network in an effective and efficient manner with minimal overhead. The system and method enables an ad-hoc communication network to maintain connectivity between intelligent access points of the network and mobile nodes in the network while performing an on-demand protocol. The system and method further uses an improved distance vector routing algorithm and unicast messages, to thus avoid an increase routing advertisement frequency in the network while keeping network overhead at a minimum. The system and method also modifies the Ad Hoc On-Demand Distance Vector Routing (AODV) protocol to facilitate smooth handoff of subscriber devices in an ad-hoc communication network while also eliminating unidirectional links between nodes in the network.

Abstract: A system and method for synchronizing a wireless network comprising a first node operable pursuant to a first time-division multiple access (TDMA) scheme and a second node operable pursuant to a second TDMA scheme, wherein the first TDMA scheme and the second TDMA scheme each comprise a plurality of ticks, and wherein the first node and the second node each comprise a tick counter for determining the time moment at which a transmission is made or at which a signal is received by the node.

Abstract: A system and method for providing a MAC protocol that optimizes communication within a wireless network. Specifically, the system and method operates with Mobile Terminals, Fixed References and at least one Main Control, wherein a method defines the sequence of messages exchanged between each Mobile Terminals, Fixed Reference and the Main Control for assuring the data is optimally communicated within the network.

Abstract: A power line communications (PLC) system and method for providing broadband communications over a low voltage power line are disclosed. The system and method comprise a manager that controls access to a bridge for a client where the bridge communicates with the manager to provide the client Internet access. The bridge modulates Ethernet communications from the Internet access to the low voltage power line to provide the modulated Ethernet communications to the client and the client demodulates modulated Ethernet communications from the low voltage power line to yield Ethernet communications.

Abstract: A communications network which is capable of effectively and efficiently handling mobility of wireless user terminals between access point nodes of a packet-switched network with minimal overhead and packet loss, and a method for using the same. The communications network employs a packet-switched core network and a plurality of access points coupled to the core network. Each access point is adapted to provide any user terminal with wireless communications access to the core network when that user terminal becomes affiliated with that access point. Each access point, as well as other nodes on the network such as a media server, DNS server and an IP gateway router, includes an address resolution cache which is adapted to store information representative of affiliation between the user terminals and the access points of the network.

Abstract: Site, frequency, and backhaul planning for access points is disclosed where the placement of coverage access points in an urban area requires taking a section of a grid of size 2K by 2K blocks where K is a range of a coverage access point and placing a first coverage access point at a first intersection within the grid wherein the first intersection is defined by a first street and a second street. Removing the first street and the second street from the list and placing a second coverage access point at a second intersection considering the streets in the list. Iterating through the streets in the list until each street has a coverage access point. Further disclosed is frequency planning for the site and backhaul planning for the site.