摘要:
In one aspect, a wireless system includes an encoder configured to encode data using a spinal code which uses a function over the message bits to directly produce a sequence of constellation symbols for transmission. The wireless system also includes a decoder configured to decode the spinal code. The function may be at least one of a non-linear function and a hash function.
摘要:
In some embodiments, a method of providing a user with a roadway route to a destination that maximizes the probability of reaching the destination by a deadline includes providing a database of traffic delay probability distributions based on historical traffic delay information, performing route-planning using at least one of the traffic delay probability distributions and parametric optimization to determine at least one route to the destination that maximizes the probability of reaching the destination by the deadline, and displaying the at least one route to the user. In some embodiments, the database includes a mean value and a variance value associated with each route from a plurality of routes stored at the database, and the performing includes the following steps: defining a first set of routes from the plurality of routes, selecting a first route from the plurality of routes as a current optimal route, defining a second set of routes and a third set of routes based on the first route, and discarding the second set of routes.
摘要:
Described herein are new error-correction (channel) codes: permute codes, iterative ensembles of permute and spinal codes, and graphical hash codes. In one aspect, a wireless system includes an encoder configured to encode data using one of the aforementioned channel codes. The wireless system also includes a decoder configured to decode the encoded data.
摘要:
A method and network architecture for implementing an energy efficient network. The network includes a plurality of nodes that collect and transmit data that are ultimately routed to a base station. The network nodes form a set of clusters with a single node acting as a cluster-head. The cluster-head advertises for nodes to join its cluster, schedules the collection of data within a cluster, and then transmits the data to the base station. A cluster can intelligently combine data from individual nodes. After a period of operation, the clusters are reformed with a different set of nodes acting as cluster-heads. The network provides an increased system lifetime by balancing the energy use of individual nodes.
摘要:
The position and orientation of a mobile unit is determined from ultrasonic waves received from beacons of known location. Orientation is determined from a phase difference of the sensed ultrasonic wave at plural receivers on the mobile unit. Signals from multiple beacons may be processed to solve for x, y and z position and for speed of sound. The receivers are spaced at greater than a half wavelength of the ultrasonic wave and signals from plural receivers are processed to remove multiple wavelength phase ambiguity. Two non-collinear sets of collinear receivers allow ambiguity resulting from symmetry of the receivers to be broken.
摘要:
Described herein are new error-correction (channel) codes: permute codes, iterative ensembles of permute and spinal codes, and graphical hash codes. In one aspect, a wireless system includes an encoder configured to encode data using one of the aforementioned channel codes. The wireless system also includes a decoder configured to decode the encoded data.
摘要:
An approach to telematics using mobile devices provides battery-efficient trajectory and mileage inference from inaccurate and intermittent location data. Accurate trajectories of how users or vehicles move in the physical world are formed by processing raw position estimates obtained from noisy, inaccurate, and error-prone position sensors on mobile devices, where the position data may also arrive intermittently with long time gaps. The trajectory is formed using the process of map matching, which determines the trajectory on a map that best explains the sequence of position observations.
摘要:
A method, apparatus and computer program product for providing partial packet recovery (PPR) for wireless networks is presented. PPR incorporates an expanded physical layer (PHY) interface that provides PHY-independent hints to higher layers about the PHY's confidence in each bit it decodes, and a technique to recover data even when a packet preamble is corrupted and not decodable at the receiver. Also described is an asynchronous link-layer automatic repeat request (ARQ) protocol built on PPR that allows a receiver to compactly encode a request for retransmission of only those bits in a packet that are likely in error.
摘要:
A method for selecting a queue for service across a shared link. The method includes classifying each queue from a group of queues within a plurality of ingresses into one tier of a number “N” of tiers. The number “N” is greater than or equal to 2. Information about allocated bandwidth is used to classify at least some of the queues into the tiers. Each tier is assigned a different priority. The method also includes matching queues to available egresses by matching queues classified within tiers with higher priorities before matching queues classified within tiers with lower priorities.
摘要:
A method and apparatus for selecting a queue for service across a shared link. The method includes determining a priority for each queue (202) within a plurality of ingresses (102), wherein the priority is instantaneous for a given timeslot for data transfer, selecting a queue having a first priority for each group of queues within each ingress (104) having packets destined for a particular egress (104), selecting a queue having a second priority for each subset of queues having first priorities and having packets destined for the particular egress (104), and selecting the queue having the second priority for service across the shared link in the given timeslot.