摘要:
A power amplifier system uses adaptive distribution of signals through an amplifier architecture of parallel amplifier stages. For example, the power amplifier system can adjust the operation of individual amplifier stages in the amplifier arrangement, for example to reduce power handling capability of the amplifier stages based on information of the signal to be amplified by the amplifier arrangement, such as the power level. To take advantage of the adjusted operation of the amplifier stages, the power amplifier system uses a variable power divider to reapportion the input signal power among the amplifier stages and at least one variable combiner to adaptively combine amplified signals from the amplifier stages in changing proportions. As such, the power amplifier system is reconfigurable and/or can adapt to changing conditions to provide improved performance and/or efficiency.
摘要:
A signal amplification system involves transforming at least one signal to be amplified into at least one transformed signal which is amplified and the resulting amplified transformed signal(s) can be used to produce a version(s) of the at least one original signal. The at least one transformed signal can be produced from the at least one original signal by using the at least one original signal to amplitude and/or angle (phase or frequency) modulate the at least one original signal. After amplification of the at least one transformed signal, the resulting at least one amplified transformed signal is de-modulated to produce a version(s) of the at least one signal. In transforming the at least one original signal to produce the at least one transformed signal, the at least one original signal is transformed into a more desirable form, such as a more power efficient form, for amplification. By amplifying the at least one transformed signal, more efficient and/or less costly amplifier(s) can be used to amplify the at least one signal in a linear fashion. Depending on the embodiment, at least one signal to be amplified can be transformed into at least one transformed signal by combining offset versions of the at least one original signal to produce the at least one transformed signal having the energy of the at least one signal spread in time and/or to produce the at least one transformed signal having a reduced peak to average power ratio(s)(PAR). Multiple signals to be amplified can be transformed into at least one transformed signal by combining the multiple signals, for example to produce the at least one transformed signal having a reduced peak to average power ratio(s) (PARs). After the at least one transformed signal is amplified, the resulting signal(s) can be de-modulated, inversely transformed, de-spread or reconstructed to recover a version(s) of the original signal(s).
摘要:
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.
摘要:
Disclosed is a trust management system for decision fusion in a network. The trust management system includes a detection subsystem having a plurality of sensors, and a plurality of channels. Each sensor of the plurality of sensors detects one of an occurrence and a non-occurrence of an event in the network. The trust management system further includes a fusion subsystem communicably coupled to the detection subsystem through the plurality of channels for receiving a decision of the each sensor and iteratively assigning a pre-determined weightage. The fusion subsystem ascertains a summation of respective decisions of the plurality of sensors and compares the weighted summation with a corresponding decision of the each sensor. The fusion subsystem further updates the assigned pre-determined weightage and determines the presence of the each sensor being one of a compromised sensor and a non-compromised sensor. Further disclosed is a method for decision fusion in a network.
摘要:
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.
摘要:
A node in a wireless communication network comprises a processor that receives information regarding a first plurality of packets to be transmitted in an epoch, a first path of nodes for the first plurality of packets, and a first flow rate. The processor receives information regarding a second plurality of packets to be transmitted in the epoch, a second path of nodes for the second plurality of packets, and a second flow rate. The processor determines weights for the paths based on the flow rates. The processor assigns pipelines for the paths and creates groups of pipelines based on the weights. The groups may be assigned to a schedule.
摘要:
A gain and phase control system performs a gain (or phase) adjustment based on the results of a previous gain (or phase) adjustment after an intervening phase (or gain) adjustment. A gain adjustment is based on the results of a previous gain adjustment rather than on the results of an intervening phase adjustment. A phase adjustment is based on the results of a previous phase adjustment rather than the results of an intervening gain adjustment. As such, the above-mentioned increase in error signal does not occur because a gain adjustment is based on the results of the previous gain adjustment, and a phase adjustment is based on the results of the previous phase adjustments. In accordance with another aspect of the present invention, the gain and phase control system makes a gain (or phase) adjustment in parallel with detecting the results from a previous phase (or gain) adjustment, thereby taking advantage of the delay between adjustment and detection of the resulting error signal to improve the convergence rate. For example, the gain and phase control system can perform single alternating gain and phase adjustments and make a gain (or phase) adjustment while detecting the error signal resulting from a preceding phase (or gain) adjustment. When the error signal resulting from the gain (or phase) adjustment is being detected, the gain and phase control system makes a phase (or gain) adjustment using the results detected from the preceding phase (or gain) adjustment.
摘要:
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.
摘要:
A node in a wireless communication network comprises a processor that receives information regarding a first plurality of packets to be transmitted in an epoch, a first path of nodes for the first plurality of packets, and a first flow rate. The processor receives information regarding a second plurality of packets to be transmitted in the epoch, a second path of nodes for the second plurality of packets, and a second flow rate. The processor determines weights for the paths based on the flow rates. The processor assigns pipelines for the paths and creates groups of pipelines based on the weights. The groups may be assigned to a schedule.
摘要:
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.