Abstract: A communications system and method for exchanging spectrum usage information through a drop box (100) includes one or more central stations (101) that defines a region of operation. A central drop box (102) is associated with the central station (101) for providing a database of spectrum usage information. Stations (103, 105, 107) using the communications system may submit information regarding spectrum usage to the central drop box (102) that affects the region of operation (109, 115) for providing the most efficient and non-interfering uses of the frequency spectrum.

Abstract: A method is provided to determine optimal data rate and packet length in mobile networks. The method directly determines the optimal packet length (L) and data rate (D), which allows fast convergence in the mobile channel. The method automatically identifies and quantifies channel conditions, as well as adjusts parameters according to changes of channel conditions. A variable (Channel condition Index (CCI)) is abstracted from simulations and then used to describe and quantify the impact of three components of channel conditions: signal-to-noise ratio (SNR), multipath environment and velocity. Based on packet completion rate (PCR) status, the channel condition is identified in terms of CCI value. Once CCI is identified, the model of effective throughput G is directly optimized to locate the best packet length (L) and data rate (D).

Abstract: A method provides for identifying short radar signals in presence of interfering signals from various sources applicable to U-NII devices. The method includes collecting a set of information about received interfering signals until the End-Of-Burst (EOB) condition is identified. When the EOB is identified, the set information about the received train of interfering signals is processed. The algorithm selects the time interval between two pulses as a possible Pulse Repetition Interval (PRI) and checks if the same time interval or a multiple of it can be found between other pulses in the collected set, with some small acceptable error. Pulses matching the criteria are considered as potential radar pulses. When at least one pulse has been identified as a potential radar pulse for a number of times larger than a predefined limit, it is concluded that that pulse has been generated by a radar installation.

Abstract: A method and apparatus for operation of a node within a mobile ad hoc cognitive radio network is provided. The method includes sensing at least one assigned communications channel. Sensing at least one assigned communications channel includes measuring a value of at least one parameter corresponding to the communications channel. The method further includes comparing the measured value of the at least one parameter with a set of stored values of the at least one parameter to determine a change in the measured values. Finally a sleep mode of the node is activated for a time period, wherein the time period is determined using the change in the measured values.

Abstract: A method is provided to determine optimal data rate and packet length in mobile networks. The method directly determines the optimal packet length (L) and data rate (D), which allows fast convergence in the mobile channel. The method automatically identifies and quantifies channel conditions, as well as adjusts parameters according to changes of channel conditions. A variable (Channel condition Index (CCI)) is abstracted from simulations and then used to describe and quantify the impact of three components of channel conditions: signal-to-noise ratio (SNR), multipath environment and velocity. Based on packet completion rate (PCR) status, the channel condition is identified in terms of CCI value. Once CCI is identified, the model of effective throughput G is directly optimized to locate the best packet length (L) and data rate (D).

Abstract: A method for measuring the time of arrival of radio signals within a network comprises receiving the received signals including at least a first pseudorandom code and a second pseudorandom code from at least one other node; identifying a frequency difference between the node and the other node using a phase difference between each of a maximum value of a cross-correlation provided by the first pseudorandom code and the second pseudorandom code; applying the frequency difference to the reception of the received signal; and calculating the time of arrival of the received signal comprising a time, measured with a local clock, when the cross-correlation has achieved the maximum value.

Abstract: A method for routing data packets from a source to a destination in a wireless communication network comprising a plurality of nodes, wherein each node is in uplink-downlink association with at least one neighboring node, and wherein each node comprises a registration table identifying all downlink nodes that are associated with the node, the method comprising: sending an Open Stream message from a source node which specifies a destination node; and receiving the Open Stream message at the uplink node of the source node, wherein the uplink node relays the Open Stream message to the destination node if the destination node is registered in the registration table of the uplink node.

Abstract: A terminal for operation within an ad-hoc, peer-to-peer radio system wherein the system includes a series of radio terminals forming a service group. The terminal having a transceiver for communicating with terminals in the same service group, computer means, and memory for storing program software. Within the system, the terminal establishes a connection with one radio terminal based on time-division access; initiating an outgoing call from the radio terminal including registering with another radio terminal for serving as a node in the call connection by transmitting a registration request; and initially transmitting said registration request on a last time slot (TS) of a respective time frame (TF), said last time slot serving as a configuration channel.

Abstract: A method for routing data packets from a source to a destination in a wireless communication network comprising a plurality of nodes, wherein each node is in uplink-downlink association with at least one neighboring node, and wherein each node comprises a registration table identifying all downlink nodes that are associated with the node, the method comprising: sending an Open Stream message from a source node which specifies a destination node; and receiving the Open Stream message at the uplink node of the source node, wherein the uplink node relays the Open Stream message to the destination node if the destination node is registered in the registration table of the uplink node.

Abstract: A method provides for identifying short radar signals in presence of interfering signals from various sources applicable to U-NII devices. The method includes collecting a set of information about received interfering signals until the End-Of-Burst (EOB) condition is identified. When the EOB is identified, the set information about the received train of interfering signals is processed. The algorithm selects the time interval between two pulses as a possible Pulse Repetition Interval (PRI) and checks if the same time interval or a multiple of it can be found between other pulses in the collected set, with some small acceptable error. Pulses matching the criteria are considered as potential radar pulses. When at least one pulse has been identified as a potential radar pulse for a number of times larger than a predefined limit, it is concluded that that pulse has been generated by a radar installation.

Abstract: A method for measuring the time of arrival of radio signals within a network comprises receiving the received signals including at least a first pseudorandom code and a second pseudorandom code from at least one other node; identifying a frequency difference between the node and the other node using a phase difference between each of a maximum value of a cross-correlation provided by the first pseudorandom code and the second pseudorandom code; applying the frequency difference to the reception of the received signal; and calculating the time of arrival of the received signal comprising a time, measured with a local clock, when the cross-correlation has achieved the maximum value.

Abstract: A communications system and method for exchanging spectrum usage information through a drop box (100) includes one or more central stations (101) that defines a region of operation. A central drop box (102) is associated with the central station (101) for providing a database of spectrum usage information. Stations (103, 105, 107) using the communications system may submit information regarding spectrum usage to the central drop box (102) that affects the region of operation (109, 115) for providing the most efficient and non-interfering uses of the frequency spectrum.

Abstract: A method and apparatus for operation of a node within a mobile ad hoc cognitive radio network is provided. The method includes sensing at least one assigned communications channel. Sensing at least one assigned communications channel includes measuring a value of at least one parameter corresponding to the communications channel. The method further includes comparing the measured value of the at least one parameter with a set of stored values of the at least one parameter to determine a change in the measured values. Finally a sleep mode of the node is activated for a time period, wherein the time period is determined using the change in the measured values.

Abstract: A method and system for determining the time of arrival of a direct radio signal. The system including a receiver (210) for receiving a plurality of signals, wherein each of the plurality of received signals has an associated time of arrival. The system further including a processor (215) adapted to compute a impulse response function of a received signal; decompose an impulse response function comprising the time of arrival for each of the plurality of received signals; and identify a smallest time of arrival from the decomposed impulse response function.

Abstract: A system and method for providing geographic location information to of at least one fixed reference device in a wireless network, the method comprising: determining a geographic location of the at least one fixed reference device within an image, such as a Geographic Information System (GIS) image, where the GIS image comprises a plurality of pixels each having an absolute geographic location value associated with it, and where the geographic location of the at least one fixed reference device is defined with respect to the absolute position values associated with at least one pixel that is proximal to an image of the at least one fixed reference device within the GIS image; and providing the determined geographic location information to the at least one fixed reference device.

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: 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 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 method for measuring the Time Of Arrival of signals in a communications network is provided. A transmitter emits a beacon that is a digital message of known content, followed by timing information. The message is preceded by a pseudo-random binary phase-shift keying (BPSK) modulated sequence that allows the receiver to synchronize on the received signal using the autocorrelation method. During the synchronization process, are computed the approximated Time Of Arrival (TOA) and approximated frequency difference between the local oscillator and the received signal. The content of the beacon message is then used for correcting the approximated TOA and the frequency differences, providing results of very high precision of TOA. The timing information that follows the beacon is used for network clock synchronization and for computing the distances between network nodes.