499 results about "Collision free" patented technology

Systems and methods are provided that facilitate distributed TDMA communication amongst nodes in an ad hoc wireless network without the need for centralized management and control. A wireless communication device includes a MAC layer that is configured to synchronize its local clock from a beacon frame that is sent by another node in the ad hoc network. After synchronizing its clock to the ad hoc network, the device identifies a timeslot for transmission. When the timeslot arrives, the device senses the channel to determine if there is traffic and if there is no traffic, the device reserves the timeslot by transmitting. In this fashion, a plurality of timeslots can be divided amongst the devices in the ad hoc wireless network for optimized collision free communication using distributed TDMA. This distributed TDMA communication can also be applied across multiple channels in a wireless network to significantly increase bandwidth and quality-of-service.

A hash-optimized backup system and method takes data blocks and generates a probabilistically unique digital fingerprint of the content of each data block using a substantially collision-free algorithm. The process compares the generated fingerprint to a database of stored fingerprints and, if the generated fingerprint matches a stored fingerprint, the data block is determined to already have been backed up, and therefore does not need to be backed up again. Only if the generated fingerprint does not match a stored fingerprint is the data block backed up, at which point the generated fingerprint is added to the database of stored fingerprints. Because the algorithm is substantially collision-free, there is no need to compare actual data content if there is a hash-value match. The process can also be used to audit software license compliance, inventory software, and detect computer-file tampering such as viruses and malware.

An ad hoc network organizes itself to provide communications without need for an a priori designated central control mechanism or base stations. Such self-organization is challenging in a multihop ad hoc network having member nodes that are highly mobile and widely distributed. A Synchronous Collision Resolution (SCR) protocol and a Node State Routing (NSR) protocol are well suited to provide efficient ad hoc network organization. SCR is an access protocol that achieves high capacity collision free access using a signaling approach that creates a random cellular-like network after each signaling period. NSR is a routing protocol that uses the dissemination of node states to predict link availability and to assign metrics to those links for the creation of optimized routes. In use, the present invention provides quality of service and supports energy conservation for the mobile nodes.

A method is provided for multiple remote units (RU)s to efficiently utilize resources on a shared OFDM high speed data channel without collisions. A collision occurs when two or more RUs transmit on the same frequency at the same time. The method defines two distinct states for accessing the channel. These are the Arbitration state and the Data Transfer state. A base station transmits a flag on the downlink to notify the RUs of which state is in effect. RUs having a data message notify the base station by transmitting a frequency tone, which acts as a request to transmit data, during the arbitration state. The tone frequencies are frequency spaced to be mutually orthogonal, so that the base station can receive all the uplink requests simultaneously. Upon receiving the uplink request signals, the base station establishes the data transfer state and orders the uplink data messages from the remote units is a non-interfering sequence. A system for preventing uplink data message collisions in an OFDM communications system is also provided.

A method for conveying digitally encoded data within a Wireless Local Area Network (WLAN) using a contention based Media Access Control (MAC) protocol. In the method, a multi-beam access point can transmit a channel contention request and responsively receive channel contention responses. A set of nodes can be determined based upon the channel contention responses. Each node of the determined set can be assigned one beam of the multi-beam access point. The nodes can use the assigned beams to simultaneously communicate with said multi-beam access point in a collision-free fashion along an assigned beam.

A wireless terminal comprising a radio transceiver for communicating with a base station, an infrared transceiver for communicating with another wireless terminal, a congestion control unit for detecting whether radio communication with the base station is in a collision-free state, and a communication control unit for performing radio communication with the base station by the radio transceiver after detecting unoccupied state in the radio channel by the congestion control unit and transmitting identification information to another wireless terminal by the infrared transceiver when the radio communication with the base station is completed.

A method, a drone device, and an adaptive robot control system (ARCS) for adaptively controlling a programmable robot are provided. The ARCS receives environmental parameters of a work environment where the drone device operates and geometrical information of a target object to be operated on by the programmable robot. The ARCS dynamically receives a calibrated spatial location of the target object in the work environment based on the environmental parameters and a discernment of the target object from the drone device. The ARCS determines control information including parts geometry of the target object, a task trajectory of a task to be performed on the target object, and a collision-free robotic motion trajectory for the programmable robot, and dynamically transmits the control information to the programmable robot via a communication network to adaptively control the programmable robot while accounting for misalignments of the target object in the work environment.

The present invention discloses a method for increasing the channel capacity of a communications network, comprising a plurality of one-way TDMA transmitters sharing said channel, and at least one compatible receiver, by reducing transmission collisions among said transmitters. This is achieved by coupling a Global Navigation Satellite System (GNSS) decoder, such as a GPS receiver, to each transmitter, and limiting transmissions to discrete time slots, determined by timing signals provided by said GNSS. Further, this basic set of time slots is divided into several sub sets, and each transmitter selects a sub set of time slots according to its geographic location, in order to enable reusing time slots in spaced apart areas, as frequencies are reused in cellular networks. Then, each transmitter selects its own transmission time slot, from said sub set, in a way that statistically minimizes collisions among nearby transmitters. The present invention does not intend to ensure collision-free communications, yet is projected to reduce the transmission collision rate among simplex in nature transmitters, which have no means to detect other transmissions, or discover if a transmission was successful. One embodiment of this invention is related to distress radio beacons in satellite based Search and Rescue (SAR) systems, such as Cospas-Sarsat.

The invention, which belongs to the technical field of unmanned vehicles, relates to a dynamic obstacle avoiding method based on collision detection. A desired vehicle trajectory is constructed by initial planning; according to a received dynamic obstacle prediction trajectory and the desired vehicle trajectory, collision detection is performed; the driving speed and/or path of the vehicle are/isplanned again to obtain collision-free driving speed and/or path data of the vehicle are obtained; and a desired vehicle trajectory is reconstructed to avoid the dynamic obstacle. Therefore, the unmanned vehicle can avoid the dynamic obstacle autonomously. According to the invention, with the collision detection method for the automatic driving vehicle, the high collision detection accuracy is ensured and the collision detection efficiency is improved in a dynamic environment. On the basis of the re-planning method, the high traffic efficiency, the high traffic smoothness and the good trafficsafety effect are considered simultaneously.

A wireless communication network includes a network coordinator (NC) having plural channels and plural wireless transceivers, and plural nodes. Each node has status information, a number of channels and a number of wireless transceivers. Each node and the NC communicate in a Carrier Sense Multiple Access mode. Each node communicates the status information thereof to or toward the NC in a Time Division Multiple Access mode having plural time slots. The NC assigns the time slots and the channels to the nodes to provide a plurality of collision-free schedules therefor. The NC sends, for each node, a corresponding one of the collision-free schedules to or toward a corresponding one of the nodes. Each collision-free schedule includes a corresponding number of the time slots and a corresponding number of the channels that the corresponding one of the nodes employs to communicate the status information thereof to or toward the NC.

A data migration system supports a low-latency and reduced overhead data storage protocol for data storage sharing in a non-collision fashion which does not require inter-communication and permanent arbitration between data storage controllers to decide on the data placement/routing. The multiple data fragments of data sets are prevented from routing to the same storage devices by a multi-step selection protocol which selects (in a first phase of the selection routine) a healthy highest ranked drive enclosure, and further selects (in a second phase of the selection routine) a healthy highest-ranked data storage controller residing in the selected drive enclosure, for routing data fragments to different storage pools assigned to the selected data storage devices for exclusive “writing” and data modification. The selection protocol also contemplates various failure scenarios in a data placement collision free manner.

The present invention provides an intersection condition-orientated unmanned vehicle trajectory planning method based on the Bezier curve and the VFH algorithm. The method includes the following steps that: 1) the starting point pose P0 (x0,y0,theta0) and destination point pose P3 (x3,y3,theta3) of current trajectory planning are acquired; 2) a trajectory cluster A1 from the starting point pose P0 (x0,y0,theta0) to the destination point pose P3 (x3,y3,theta3) is generated through adopting a three-order Bezier curve model; 3) the trajectory cluster A1 is screened according to a maximum curvature constraint, so that a trajectory cluster A2 is obtained, collision detection is performed on A2, so that a collision-free trajectory cluster A3 is obtained; 4) if A3 is not empty, an optimal trajectory is selected from A3 according to a trajectory smoothest principle and is outputted to a control layer, and the method is terminated, otherwise, the method shifts to step 5; 5) a movement region in the original VFH algorithm is improved, so that a fan-shaped movement region is built; 6) obstacle information is utilized to establish a grid map; 7) the fan-shaped movement region is divided into a plurality of fan-shaped regions, and whether an obstacle exists is judged; 8) the Bezier curve is used in combination, and optimal trajectory points are selected; and 9) with a discrete point set generated in the step 8 adopted as control points, a B-spline curve is generated, and the B-spline curve is adopted as the final trajectory of an unmanned vehicle.

The invention discloses a planning method for a mixed path of a mobile robot under a multi-resolution barrier environment. The invention aims to solve the problems of blindness of initial planning, environment modeling lack of flexibility and poor real-time obstacle avoidance capability of the present method. According to the technical scheme, a self-adapting inhomogeneous polar-radius polar coordinate modeling method is adopted for performing environment modeling on the motion space of the mobile robot; a gravity particle swarm searching method is adopted for planning an initial overall path from starting point to ending point; according to the initial overall path, a modified artificial potential field method is adopted for performing local dynamic obstacle avoidance by estimating the minimum safe distance and safe collision-preventing angle and for arriving at each initial overall path point in turn; and a final overall collision-free path is output after arriving the planning end point. According to the planning method provided by the invention, the blindness of initial overall planning and the environment modeling flexibility can be effectively improved, the real-time obstacle avoidance capability for dynamic unknown barrier is strong, and the method is high in speed, high in precision and strong in adaptability.

A method and arrangement are described for manoeuvre generation for automated driving on a one-way road of a vehicle (e) hosting the arrangement, the host vehicle (e) further including one or more advanced driver assistance systems. A collision free reference trajectory for longitudinal and lateral movement of the host vehicle (e) is determined repeatedly, with a fix time interval, for allowing the host vehicle (e) to retain a desired velocity and maintain the host vehicle (e) in a preferred lane utilizing model predictive control and quadratic program formulation. A control scheme where the structured environment of the one-way road is exploited in order to linearly formulate collision avoidance constraints is utilized. Manoeuvre generation is performed through solving the quadratic program. The one or more advanced driver assistance systems are controlled to perform the generated manoeuvre.

A method for collocated nodes communicating over a first interface to agree on a conflict-free transmission schedule among themselves, which they can then use to collaborate with neighbors accessed through a second interface, for example through wireless links in order to obtain collision-free transfers of unicast, multicast and broadcast packets over wireless channels, and channel access delay guarantees. The collocated nodes behave as a single virtual node for the purpose of establishing a consistent transmission schedule throughout the nodes of a multihop wireless network.

An embodiment of the invention provides a path planning method for robot fast collision avoidance. The method comprises using a BBRrt algorithm and a collision detection algorithm based on the convex set theory, extending alternatively from initial configuration and target configuration to opposite configuration form two balance RRT trees, quickly finding, in a configuration space, a collision-free motion path connecting the initial configuration and the target configuration, effectively passing through a narrow channel and avoiding collision with obstacles in the environment, making full use of a multi-step expansion method and a balance extension method with an inspiring purpose, and thus effectively improving the convergence and repeatability of the RRT algorithm. Based on the convex set theory, a convex hull fast collision detection algorithm constituted by a linear inequation group is provided, and the efficiency and performance of a collision detection module in the path planning method for collision avoidance can be improved. The method provided by the invention can be extended to high-dimensional robot multi-tree RRT path planning.

Embodiments herein provide methods and systems for enhancing interference mitigation using conjugate symbol repetition and phase randomization on a set of subcarriers. The repeated data tone in the signal is complex-conjugated before transmission, when the repetition factor is two. When the repetition factor is greater than two, a combination of conjugate repetition and random/deterministic phase variation of the repeated tones is used to mitigate the interference mitigation. Embodiments further disclose Collision Free Interlaced Pilot PRU Structures that can be used with or without conjugate symbol repetition and phase randomization for interference mitigation.

A family of medium-access (MAC) collision-avoidance receiver-initiated channel-hopping (RICH) protocols which do not rely on carrier-sensing, or unique codes to each node within the network. The RICH protocol requires that each network nodes adhere to a common channel-hopping sequence, and that nodes that are not in a state of sending or receiving data will listen on the common channel hop. To send data nodes enter into a receiver-initiated dialogue over the channel-hop at the time at which a data transmission is needed. Nodes which succeed in performing the collision-avoidance handshake remain in the same channel-hop for the remainder of the data transfer, while the remaining nodes continue with the common channel hopping sequence. The described RICH protocols are capable of providing collision-free operation even in the presence of hidden terminals.