Abstract: A system and method for deploying a network of wireless devices, including mobile terminals, wireless routers and a least one control console, within a three dimensional deployment area such as a building, so that communication, identification and position calculations of personnel, such as firefighters, using the mobile terminals can be achieved regardless of building structure. The wireless routers are deployed in a substantial vertical manner in staircases and elevator shafts of a building of interest, either in advance as part of a safety program or immediately upon arrival of firefighters or other team at the building during an emergency. The system and method according to the embodiment of the present invention described herein uses both TOF and RSSI between the mobile terminals and wireless routers to identify the floor numbers where firefighters are located and to track firefighter movements.

Abstract: A system and method including an algorithm that can use the linear time shift property of the subcarrier modulation to provide accurate frame synchronization for communications between nodes in a wireless network, where nodes employ orthogonal frequency division multiplexing (OFDM) modems. The subcarrier modulation is typically performed with a Fast Fourier Transform (FFT) that includes a time shift between Inverse Fast Fourier Transform (IFFT) and guard interval insertion at transmission, but due to the guard insertion, the system and method of the present invention corrects the time shifts allowing accurate TOF calculations.

Abstract: A system and method for determining the reliability of at least one communication link between nodes in an ad-hoc communication network. The system and method perform the operations of receiving at a first node data sent by a second node over a link from the second node to the first node, determining a bit error rate (BER) at which the first node received the data, and identifying the link from the second node to the first node as being reliable when a value determined based on at least the BER and, more specifically, an aggregate of the BER and BERs of data received by the first node from the second node over a period of time, meets a desired condition. The data sent by the second node can include routing advertisement data indicating at least one node which is a neighboring node of the second node, or can be any suitable regularly expected message.

Abstract: A system and method for calculating an optimum transmission power level in an ad-hoc network communication path having a maximum number of transmission hops. The system and method calculates an optimum transmission power level for transmission routes having a maximum number of hops between nodes and transmits the communication using the calculated power level such that a transmission path is achieved that results in a maximum pipeline delay during transmission that does not exceed allowable levels for the service class provided.

Abstract: A system and method for maximizing channel utilization by efficiently allocating codes and frequencies based on estimated relative interference between subscriber units in a wireless communications network, such as an ad-hoc wireless communications network, in such a way as to minimize multiple access interference. The system and method perform the operations of collecting existing and proposed transmission information between nodes in the network, and calculating a respective interference factor for each existing transmission between certain nodes and each proposed transmission by a transmitting node. The interference factors can be calculated based on, for example, respective distances between certain nodes. The system and method then assign the communications channel configuration, including a frequency channel and code channel, to the transmitting node for communications to other nodes as designated by a minimum of the calculated respective interference factors.

Abstract: A novel protocol for an ad-hoc, peer-to-peer radio network that provides collision-free channel access with an emphasis on improving geographic reuse of the frequency spectrum. The protocol of the invention is executed on the reservation or control channel, and provides a method for allocating data transactions on the data channels. The system of the invention utilizes multiple parallel data channels that are coordinated by a single reservation channel. The transceiver of the system employs two modems to solve the channel reliability issues with multiple channel designs, where one is dedicated as a receive-only modem for gathering channel usage information on the reservation channel. High quality voice, video and data may be transmitted. The reservation channel implements a time division multiple access algorithm with dynamic slot allocation. In a distributed manner, nodes determine geographic reuse of slots based on channel quality extracted from the modem.

Abstract: A communication device (105,200) includes a cordless telephone (205) and a two way radio (210). The communication device (105,200) is adapted to place an active cordless telephone call in a low frequency mode in response to receiving an incoming two way radio communication. The communication device (105,200) is adapted to then establish communication within the two way radio communication. The communication device (105,200) periodically re-establishes the cordless telephone call to maintain communication with a cordless base station (120) until the two way radio communication is completed.

Abstract: An antenna system (100) comprising a first electromagnetic radiator (102) and a second electromagnetic radiator (104) is provided. The first electromagnetic radiator incorporates an off-center series feed (112) at a pre-defined distance from a first end (114) of the antenna system. The second electromagnetic radiator incorporates a shunt feed (120) at a second pre-defined distance from a second end (122) of the antenna system. The first electromagnetic radiator is used primarily for plural band transmission-reception and the second electromagnetic radiator for antenna diversity band reception.

Abstract: An antenna system includes a stacked patch antenna (100) comprising two or more patch antennas symmetrically aligned around an axis. The stacked patch antenna (100) comprises a differential feed patch antenna. The two or more patch antennas include a first patch antenna (105) and a second patch antenna (110). At least a portion of the second patch antenna (110) serves as a ground plane for the first patch antenna (105).

Abstract: A novel protocol for an ad-hoc, peer-to-peer radio network that provides collision-free channel access with an emphasis on improving geographic reuse of the frequency spectrum. The protocol of the invention is executed on the reservation or control channel, and provides a method for allocating data transactions on the data channels. The system of the invention utilizes multiple parallel data channels that are coordinated by a single reservation channel. The transceiver of the system employs two modems to solve the channel reliability issues with multiple channel designs, where one is dedicated as a receive-only modem for gathering channel usage information on the reservation channel. High quality voice, video and data may be transmitted. The reservation channel implements a time division multiple access algorithm with dynamic slot allocation. In a distributed manner, nodes determine geographic reuse of slots based on channel quality extracted from the modem.

Abstract: A system and method for a media access control (MAC) scheduling algorithm having a distributed, self-coordinating approach to provide use fairness and service differentiation in an ad hoc network by using control RTS/CTS messages carrying node status information. A local scheduling algorithm uses the overheard RTS/CTS information with attributes specifying nodes' status to maximize the awareness of the neighborhood status for a multi-channel system where data and ACK messages are transmitted through different data channels. If the system uses a single channel, the corresponding information may be carried by using DATA or ACK messages. The algorithm measures the offered load, carried load, and backlogged load in the neighborhood to adjust the channel access timer to provide use fairness among different nodes, different links, and different streams.

Abstract: A system and method for improving the accuracy in computing the location of a mobile subscriber device connected in a wireless network. The system and method employ a predictive filter, including a measurement weight algorithm to decrease standard deviation error, to correctly determine a location of a mobile subscriber device. The predictive filter requires lower levels of computation, which allows for real-time processing on low-speed central processing units commonly used in wireless networks.

Abstract: A system and method for establishing and maintaining node clock synchronization in a wireless network. The system and method calculates the clock shift, clock drift and propagation delay values using a series of message exchanges and control algorithms between a selected reference node and a client node in a wireless network, then uses these values to synchronize the client node clock to the reference node clock.

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. The system and method further employ ad-hoc routing techniques during handoff of a wireless user terminal between access point nodes of the core network to enable the network to maintain multiple paths via which data packets are provided to the user terminal during handoff to substantially eliminate packet loss during handoff.

Abstract: A system and method for providing adaptive threshold selection for detecting a signal in the presence of interference or noise. The system and method thus enables a node, such as a mobile user terminal, in an ad-hoc communications network to reduce the number of false alarms it experiences in the detection of communications signals due to, for example, sudden noise bursts or reception of a high powered signal that overloads the automatic gain control (AGC) device of the receiver in the node. The system and method employ two correlation circuits which correlate the received signal with two reference sequences and output a correlated signal, a threshold generating circuit which generates a threshold value based on the estimation of the variance of the output of the first correlation circuit, and a comparison circuit which compares the correlated signal to the threshold value to determine whether the received signal includes a valid data signal, as opposed to only noise.

Abstract: A system and method for controlling the dissemination of Routing packets, and decreasing the latency in finding routes between nodes. The system and method provides message exchanges between wireless devices to determine optimized communication routes with a minimum of overhead messages and buffered data. Exchanged messages are reduced to a specific series of exchanges indicating destination, destination node detection, and route, preferably using a series of IAP devices. Routes are discovered in an efficient manner and latency in finding routes between nodes is reduced, thereby reducing buffered information levels at individual devices.

Abstract: A system and method for evaluating at least one communication link between a transmitting node and a receiving node in a communications network, such as a wireless ad-hoc communications network in accordance with the 802.11 standard. The system and method perform the operation of assigning respective link quality values to the respective communication links based on a transmit power level (TPL) value at which the respective data packets were transmitted by the transmitting node over the respective links, a received sensitivity (RS) value of the receiving node receiving the data packets, and a receive signal strength indication (RSSI) value provided by the network for each respective link. The system and method can examine a content of a data packet being sent between the two nodes to determine the TPL, and can receive the RSSI value from a physical layer of the communications network.

Abstract: A system and method for improved Time Of Arrival (TOA) distance measurements between nodes of a wireless ad-hoc network. Specifically, the present invention is a system and method of distance estimation using square-root raised-cosine pulse shaping and chip matched filters on direct sequence spreading waveforms, the multiplication of which produces raised-cosine filtered pulse responses. The responses are used to identify a time when a function is at a maximum, corresponding to the actual signal reception time. The system and method produces a raised-cosine filtered pulse response and an auto-correlation function based on a received signal. A peak value of the auto-correlation function is calculated based on a quadratic approximation, which is corrected using a signal sampling phase offset detected between the raised-cosine filtered pulse response and the calculated peak value. The calculated peak value is then corrected to represent an actual reception time for received signals.

Abstract: A fuel cell power source (100) for use in electronic systems includes a fuel cell system (130) and a controller (150). The controller (150) computes net power requirements of a load device from one or more power functional information sources; and determines an operating point of the fuel cell system (130) by matching the net power requirements with the power characteristics of the fuel cell system (130).

Abstract: A system and method for providing security to a wireless network by using a mobile node's location as a parameter for deciding if access is to be given to the node. The system and method employ access points, wireless routers and mobile nodes, each including at least one transceiver adapted to transmit and receive communication signals to and from other wireless routers, mobile nodes and other mobile access points. Each access point is connected to a network management system which allows enhanced network monitoring and control. Each network node includes technology which may determine an absolute node location containing latitude, longitude and altitude of a node, or a relative node location containing the distance and angle between nodes, or a combination of both absolute and relative location data.