Abstract: Message or traffic data is transmitted from a given radio or node for reception by one or more other nodes in a communications network, by arranging the node for transmitting the data according to a selected one of a number of different medium access protocols. The medium access protocol selected for a given message or traffic is determined according to one or more of (a) the size of the traffic, (b) the priority of the traffic, (c) the periodicity of the traffic, and (d) whether the traffic is broadcast or unicast to the other nodes in the network. Each radio includes one or more processor and memory modules configured to output messages or traffic for transmission from the radio according to the selected medium access protocol. By using distributed scheduling and traffic control to protect against hidden nodes, the radios can maintain agile portability in tactical urban environments.

Abstract: A method of providing medium access control for a wireless mobile ad hoc network includes defining a TDMA network timing frame including a data (DATA) zone having one or more time slots structured to support multiuser detection (MUD) of concurrent transmissions during each slot, a negative acknowledgment (NACK) zone during which nodes transmit requests for retransmission of packets destined to but not successfully received by the nodes, a broadcast (BC) zone during which network management messages are broadcast to the nodes, and a control (CTRL) zone. A primary master (PM) node is selected and operates as a source of network time for all the nodes. Each node synchronizes its time to that of the PM node during the CTRL zone in a distributed manner, by exchanging control messages with the PM node or other nodes located one or more hops from the PM node.

Abstract: In the method for operating an interference multiple access communications system, wherein the improvement comprises the steps of employing a distributed scheduler within a Media Access Controller (MAC) for Multiuser Detection (MUD) enabled Mobile Ad-hoc Networks (MANETS) to increase spectral efficiency by increasing spectral use and providing a way to dynamically allocate virtual channels to achieve maximum channel reuse in different network topologies and different link patterns and to ameliorate any hidden or exposed node problems.

Abstract: Time synchronization among nodes in a wireless mobile ad hoc network (MANET) is obtained using a cross layer approach. Each node maintains a routing table that contains entries corresponding to other nodes of the network that are one or more hops away from the node, and topology messages are exchanged periodically among the nodes in order to update their routing tables. A network master node is selected, and remaining nodes that are one or more hops away from the master node are defined as slave nodes. The master node includes master timing information in the topology messages it transmits. The timing information is concatenated to include a first time (T1) at which a topology message was received by the master from each of the slave nodes, and a second time (td) at which the master node transmits a topology message after receiving all the topology messages from the slave nodes.

Abstract: Communications in a mobile network are scheduled by defining reservation frames having time slots during which network nodes can transmit certain traffic loads while avoiding interference. The nodes maintain maps that identify the slots as either free or reserved based on each node's existing reservations, and reservation information the node receives from neighboring nodes. A node wishing to transmit traffic determines the number of slots required to carry the traffic, selects a first set of slots from among those identified in its maps as free, and transmits a reservation initiation message (RIM) that identifies the first set of slots. Nodes receiving the RIM determine which, if any, of the first set of slots are already reserved based on their own maps, and transmit counter reservation initiation messages (CRIMs) if any slots are reserved. The CRIMs also identify those slots that the CRIM transmitting nodes determine to be currently free.

Abstract: A method of providing medium access control for a wireless mobile ad hoc network includes defining a TDMA network timing frame including a data (DATA) zone having one or more time slots structured to support multiuser detection (MUD) of concurrent transmissions during each slot, a negative acknowledgment (NACK) zone during which nodes transmit requests for retransmission of packets destined to but not successfully received by the nodes, a broadcast (BC) zone during which network management messages are broadcast to the nodes, and a control (CTRL) zone. A primary master (PM) node is selected and operates as a source of network time for all the nodes. Each node synchronizes its time to that of the PM node during the CTRL zone in a distributed manner, by exchanging control messages with the PM node or other nodes located one or more hops from the PM node.

Abstract: In the method for operating an interference multiple access communications system, wherein the improvement comprises the steps of employing a distributed scheduler within a Media Access Controller (MAC) for Multiuser Detection (MUD) enabled Mobile Ad-hoc Networks (MANETS) to increase spectral efficiency by increasing spectral use and providing a way to dynamically allocate virtual channels to achieve maximum channel reuse in different network topologies and different link patterns and to ameliorate any hidden or exposed node problems.

Abstract: Time synchronization among nodes in a wireless mobile ad hoc network (MANET) is obtained using a cross layer approach. Each node maintains a routing table that contains entries corresponding to other nodes of the network that are one or more hops away from the node, and topology messages are exchanged periodically among the nodes in order to update their routing tables. A network master node is selected, and remaining nodes that are one or more hops away from the master node are defined as slave nodes. The master node includes master timing information the topology messages that it transmits. The timing information is concatenated to include a first time (T1) at which a topology message was received by the master from each of the slave nodes, and a second time (td) at which the master node transmits a topology message after receiving all the topology messages from the slave nodes.

Abstract: Communications in a mobile network are scheduled by defining reservation frames having time slots during which network nodes can transmit certain traffic loads while avoiding interference. The nodes maintain maps that identify the slots as either free or reserved based on each node's existing reservations, and reservation information the node receives from neighboring nodes. A node wishing to transmit traffic determines the number of slots required to carry the traffic, selects a first set of slots from among those identified in its maps as free, and transmits a reservation initiation message (RIM) that identifies the first set of slots. Nodes receiving the RIM determine which, if any, of the first set of slots are already reserved based on their own maps, and transmit counter reservation initiation messages (CRIMs) if any slots are reserved. The CRIMs also identify those slots that the CRIM transmitting nodes determine to be currently free.

Abstract: Message or traffic data is transmitted from a given radio or node for reception by one or more other nodes in a communications network, by arranging the node for transmitting the data according to a selected one of a number of different medium access protocols. The medium access protocol selected for a given message or traffic is determined according to one or more of (a) the size of the traffic, (b) the priority of the traffic, (c) the periodicity of the traffic, and (d) whether the traffic is broadcast or unicast to the other nodes in the network. Each radio includes one or more processor and memory modules configured to output messages or traffic for transmission from the radio according to the selected medium access protocol. By using distributed scheduling and traffic control to protect against hidden nodes, the radios can maintain agile portability in tactical urban environments.

Abstract: Methods and apparatus for transmitting and receiving symbols in a communication system having a plurality of frequency bands are provided. A first symbol is transmitted on a first tone using a first constellation mapping and a second symbol is transmitted on a second tone using a second constellation mapping different from the first constellation mapping. The first symbol is retransmitted on the second tone using the second constellation mapping and the second symbol is retransmitted on the first tone using the first constellation mapping. The first and second symbols are detected from a combination of the received transmitted and retransmitted first and second signals.

Abstract: A method of band multiplexing communications from a plurality of devices includes a rotation being established, by each device, between or among a plurality of frequency bands for transmission. A symbol set is transmitted from each device in each of the established transmission frequency bands and one device detects respective starting times of symbol sets for the other devices transmitting for one of the plurality of frequency bands. A starting time of a symbol set for the one device is selected based on the detected starting times for the other devices such that the selected start times limit interference between symbol sets transmitted by the one device and symbol sets transmitted by the other devices to less than a threshold level. The starting time of respective symbols is adjusted by the one device in subsequent transmissions for each of the established transmission frequency bands based on the selected starting time.

Abstract: A method of communication between or among a plurality of devices in a communication system using one or more frames to transmit a plurality of bits includes encoding the plurality of bits in accordance with a first puncture code in a first device of the plurality of devices, transmitting the plurality of encoded bits to a second device of the plurality of devices, and determining in the first device an error condition indicated in a received acknowledgement from the second device. When the error condition indicates a first error code, retransmitting the encoded bits in accordance with the first puncture code, and when the error condition indicates another error condition, different from the first error code, encoding the plurality of bits in accordance with a second puncture code, different from the first puncture code and transmitting the plurality of encoded bits to the second device.

Abstract: A control method of synchronizing communications between or among a plurality of devices in a communication system includes detecting beacons from the plurality of devices in the communication system, and establishing a reservation for at least a portion of the plurality of devices in the communication system. Each reservation is a frame interval in which to transmit symbols from one device to one or more of the other devices in the communications system. Each frame interval and intra-frame interval is set according to the established reservation. Each frame interval and intra-frame interval is a plural, integral number of symbol periods in duration.

Abstract: A control method of synchronizing communications between or among a plurality of devices in a communication system includes detecting beacons from the plurality of devices in the communication system, establishing a reservation for at least a portion of the plurality of devices in the communication system, each reservation being a frame interval in which to transmit symbols from one device to one or more other devices in the communications system, determining, by each device, a time-frequency code for each of the other devices in the communication system according to the detected beacons from the other devices, adjusting a frequency band for transmission by a respective device according to the determined time-frequency code, and transmitting a plurality of symbols from the respective device using the adjusted frequency band.

Abstract: Methods and apparatus for reducing discrete power spectral density (PSD) components of wideband signals transmitting blocks of data are disclosed. Discrete components are reduced by acquiring N symbols of pseudo-random data, each symbol having K bits; selecting one bit from each of the acquired symbols to generate N selected bits; selectively inverting a respective element in one of the data blocks responsive to the selected bits; acquiring one or more bits of pseudo-random data to replace a corresponding one or more respective bits of the acquired N symbols of pseudo-random data; and repeating for successive blocks of data.

Abstract: An agent-based telephony system is provided for establishing a call between two or more telephony devices interconnected through an automated call dispatch server. The automated call dispatch server includes a call control agent for processing call requests; a call resource management agent in communication with the call control agent for allocating and controlling the resources needed to establish a call between telephony devices; and a resource control agent in communication with the call resource management agent for providing a hardware-dependent interface to the telephony devices.

Abstract: Methods and computer program products for transmitting and receiving encoded signals in a wideband communication system and for generating codes for encoding the encoded signals are disclosed. The wideband communication system includes communication slots separated in frequency and/or time. The codes include components associated with each of the communication slots. A sub-carrier symbol is encoded by combining that symbol with each component of the code and modulating each symbol/component combination onto a wideband signal pulse in the communication slot corresponding to the respective component.

Abstract: An apparatus, system, method, and computer program product for determining a location of at least an image of a transmitter transmitting a signal is disclosed. The location of at least the image of the transmitter is determined by receiving a signal transmitted by the transmitter at at least three receiver antennas separated by known distances. Differences in time are then determined between receipt of the signal at one of the receiver antennas and at least two other receiver antennas. The known distances and the determined differences in receipt times are then processed to determine the location of the transmitter.

Abstract: Methods and apparatus for generating and processing wideband signals having reduced discrete power spectral density (PSD) components are disclosed. A wideband signal having reduced discrete PSD components is achieved by generating data symbols responsive to data for transmission, transforming one or more of the data symbols into a frame including one or more orthogonal frequency division multiplexing (OFDM) symbols, selectively inverting the frame responsive to a pseudo-random data sequence, and modulating wideband signal pulses of the wideband signal with the selectively inverted frame.