Abstract: Graph partitioning for massive scale graphs is described, such as for graphs having vertices representing people and edges representing connections between people in a social networking system; or for graphs where the vertices represent other items and the edges represent relationships between the items. In various embodiments a graph data allocator receives a graph vertex and its edges and allocates the vertex to one of a plurality of clusters each associated with one or more computing devices. In various embodiments the allocation is made by optimizing an objective function which takes into account both a cost of edges between clusters and a cost related to sizes of the clusters. In some examples the cost related to sizes of the clusters comprises a convex function applied to each of the cluster sizes. In examples, computations on the graph data are carried out with reduced runtimes and communications cost.

Abstract: Dynamic channel and transmission rate selection is described. In an example, a communication resource for transmitting data to a receiver is selected from several channels, each having several associated rates. The selection comprises storing a weighting factor for each channel/rate combination, monitoring transmission performance on a selected channel and rate, and inferring performance for other rates on the selected channel from the monitored performance. Each weighting factor is then updated using the monitored and inferred performances, and used to select a channel/rate combination for subsequent transmission. In another example, a communication device comprises a transmitter, a processor, and a memory arranged to store a weighting factor associated with each receiver, channel and rate combination.

Abstract: A sensor network has a plurality of wireless sensors which transmit to an intermediate receiving device which relays data to a central server. A method is provided for receiving data packets at the intermediate receiving device from a plurality of the transmitting devices. Data packets are sensed on a communication medium at the receiving device and the total traffic intensity of data packets from the transmitting devices is estimated. A detection threshold for data packets is provided and adapted as a function of the total intensity. The receiving device receives data packets with a signal strength above the current detection threshold.

Abstract: Count tracking in distributed environments is described, for example, as in data centers where many sites receive data and a coordinator node estimates a sum of the data received across the sites. Count tracking may be used in database applications, search engines, social networking applications and others. In various embodiments sites and a coordinator node work together to implement a process for summing data received at sites, where the sum takes into account both increments and decrements. In examples, a site decides whether to notify the coordinator node of a new data item according to a sampling probability that is related to an estimate of the current global sum of the data input across sites. In some examples a multi-mode algorithm is implemented which increases or decreases communication between the sites and the coordinator node according to behavior of the estimated global sum such that communications costs are optimized.

Abstract: Dynamic channel and transmission rate selection is described. In an example, a communication resource for transmitting data to a receiver is selected from several channels, each having several associated rates. The selection comprises storing a weighting factor for each channel/rate combination, monitoring transmission performance on a selected channel and rate, and inferring performance for other rates on the selected channel from the monitored performance. Each weighting factor is then updated using the monitored and inferred performances, and used to select a channel/rate combination for subsequent transmission. In another example, a communication device comprises a transmitter, a processor, and a memory arranged to store a weighting factor associated with each receiver, channel and rate combination.

Abstract: A resource allocation framework for wireless/wired networks is described. In an embodiment, methods of end host based traffic management are described which operate separately from the underlying access control protocol within the network (e.g. wireless MAC protocol or TCP). The rate limits for each flow are set based on per-flow weights, which may be user specified, and based on an estimate of the utilization of the shared resource and the rate limits are adjusted periodically so that the resource is not underutilized or saturated. Some embodiments compute a virtual capacity of the resource which is adjusted to optimize the value of the utilization and then the virtual capacity is shared between flows according to the per-flow weights. Methods for estimating the utilization of a wireless network and the capacity of a broadband access link are also described.

Abstract: A multiple independent narrow-channel wireless network and method for transmitting and received data over a wireless network using a fragmented frequency spectrum. The system and method uses a plurality of narrow wireless channels obtained from splitting a wide wireless channel. Each narrow channel performs sending, receiving, and carrier sensing. Moreover, each narrow channel is independent such that data can be sent or received without any interference from other narrow channels and without synchronization. Embodiments of the system and method include a compound radio having a compound receiver and a compound transmitter. The compound transmitter includes an inter-radiolet symbol synchronization module, to permit use of a single inverse fast Fourier transform block, and a dynamically configurable filter array, to mitigate leakage between channels. The compound receiver uses fraction data rate processing to optimize efficiency.

Abstract: The claimed subject matter provides a method for wireless communications. The method includes transmitting, by a first node in a wireless network, a first preamble. The method also includes detecting, in parallel with transmitting the first preamble, a transmission of a second preamble. A second node in the wireless network transmits the second preamble. Additionally, the method includes determining a later start between the transmission of the first preamble and the transmission of the second preamble. The method further includes terminating transmission of the first preamble the determining indicates that the transmission of the first preamble started after the transmission of the second preamble.

Abstract: Wireless protocols in the unlicensed spectrum are developed for different requirements in terms of transmit range and power, which makes it difficult for multiple nodes having disparate transmit ranges to coexist in the same unlicensed spectrum. A short-range wireless node uses adaptive preambles to signal presence to long-range wireless nodes outside of its transmit range. In addition, a long-range wireless node detects an adapter preamble and backs-off transmissions for reservation period dedicated to short-range nodes.

Abstract: Wireless protocols in the unlicensed spectrum are developed for different requirements in terms of transmit range and power, which makes it difficult for multiple nodes having disparate transmit ranges to coexist in the same unlicensed spectrum. A short-range wireless node uses adaptive preambles to signal presence to long-range wireless nodes outside of its transmit range. In addition, a long-range wireless node detects an adapter preamble and backs-off transmissions for reservation period dedicated to short-range nodes.

Abstract: A communication device cognitively monitors interference signals across a communication band so that adaptations for physical and medium access control (MAC) of data packet transmissions are appropriate for a particular interference signal. Characteristics of an interference signal of interest (e.g., bandwidth, power and/or duration relative to an average data packet transmitted over a communication channel of the communication device) are sensed for an appropriate adaptation (e.g., forward error correction, modulation technique, back off, request to send/clear to send protocol, etc.). Patterns for known types of interference sources can be compared so that when recognized an associated adaptation can be used.

Abstract: A sensor network has a plurality of wireless sensors which transmit to an intermediate receiving device which relays data to a central server. A method is provided for receiving data packets at the intermediate receiving device from a plurality of the transmitting devices. Data packets are sensed on a communication medium at the receiving device and the total traffic intensity of data packets from the transmitting devices is estimated. A detection threshold for data packets is provided and adapted as a function of the total intensity. The receiving device receives data packets with a signal strength above the current detection threshold.

Abstract: A resource allocation framework for wireless/wired networks is described. In an embodiment, methods of end host based traffic management are described which operate separately from the underlying access control protocol within the network (e.g. wireless MAC protocol or TCP). The rate limits for each flow are set based on per-flow weights, which may be user specified, and based on an estimate of the utilization of the shared resource and the rate limits are adjusted periodically so that the resource is not underutilized or saturated. Some embodiments compute a virtual capacity of the resource which is adjusted to optimize the value of the utilization and then the virtual capacity is shared between flows according to the per-flow weights. Methods for estimating the utilization of a wireless network and the capacity of a broadband access link are also described.

Abstract: Dynamic channel and transmission rate selection is described. In an example, a communication resource for transmitting data to a receiver is selected from several channels, each having several associated rates. The selection comprises storing a weighting factor for each channel/rate combination, monitoring transmission performance on a selected channel and rate, and inferring performance for other rates on the selected channel from the monitored performance. Each weighting factor is then updated using the monitored and inferred performances, and used to select a channel/rate combination for subsequent transmission. In another example, a communication device comprises a transmitter, a processor, and a memory arranged to store a weighting factor associated with each receiver, channel and rate combination.

Abstract: In example methods and algorithms, a node in a wireless mesh network calculates an estimated cost for a packet flow through the node. The estimation may be based on the back-log at the node and the cost of downstream neighbor nodes for the flow. Further, selection of a downstream flow and a downstream neighbor node may be based on the estimation. A packet re-ordering algorithm is also described which intercepts packets received at a node and delays delivery of the packet to the IP layer if an earlier packet in the sequence of packets has not been received.

Abstract: Full-duplex wireless communication is described. In an embodiment, a transceiver device having a transmitter circuit and a receiver circuit receives a data packet sent over a shared communication medium. In the embodiment, the transceiver reads the header of the data packet and starts transmitting an output signal on the same shared communication medium. Embodiments are described in which, whilst the transmission of the output signal is ongoing, the transceiver receives an impaired data signal which is made up of the payload of the data packet and interference from the output signal. In the embodiment, a cancellation signal is derived from the output signal, and this is combined with the impaired data signal to remove the interference and recover the payload of the data packet.

Abstract: A sensor network has a plurality of wireless sensors which transmit to an intermediate receiving device which relays data to a central server. A method is provided for receiving data packets at the intermediate receiving device from a plurality of the transmitting devices. Data packets are sensed on a communication medium at the receiving device and the total traffic intensity of data packets from the transmitting devices is estimated. A detection threshold for data packets is provided and adapted as a function of the total intensity. The receiving device receives data packets with a signal strength above the current detection threshold.

Abstract: A method of transmitting data across a wireless mesh network is described which uses network coding at each of the intermediate nodes between the source node and the destination node. Each intermediate node also controls the rate at which it broadcasts packets based on link congestion and the backlog of packets at each of the possible next-hop nodes for the data flow.

Abstract: Full-duplex wireless communication is described. In an embodiment, a transceiver device having a transmitter circuit and a receiver circuit receives a data packet sent over a shared communication medium. In the embodiment, the transceiver reads the header of the data packet and starts transmitting an output signal on the same shared communication medium. Embodiments are described in which, whilst the transmission of the output signal is ongoing, the transceiver receives an impaired data signal which is made up of the payload of the data packet and interference from the output signal. In the embodiment, a cancellation signal is derived from the output signal, and this is combined with the impaired data signal to remove the interference and recover the payload of the data packet.

Abstract: A sensor network has a plurality of wireless sensors which transmit to an intermediate receiving device which relays data to a central server. A method is provided for receiving data packets at the intermediate receiving device from a plurality of the transmitting devices. Data packets are sensed on a communication medium at the receiving device and the total traffic intensity of data packets from the transmitting devices is estimated. A detection threshold for data packets is provided and adapted as a function of the total intensity. The receiving device receives data packets with a signal strength above the current detection threshold.