184 results about "Carrier-sense multiple access" patented technology

Systems and methods which control communications in a carrier sense multiple access environment to provide a balance between communication sensitivity and transmission availability are shown. Adaptive interference control techniques of embodiments operate to determine a media error time metric representing the time associated with receiving interfering signals. The media error time metric of embodiments is used to adjust operation of various network systems in order to adjust communication sensitivity and / or transmission availability. Desensitizing thresholds and sensitizing thresholds may be used to define operating boundaries, such that desensitizing thresholds are used to control network desensitize actions which result in decreased error times and sensitizing thresholds are used to control network sensitizing actions which result in increased error times. Error time metrics and corresponding desensitizing and sensitizing thresholds may be utilized with respect to a plurality of radios. Embodiments provide for adjustment of control parameters based upon historical operation.

A system and method for achieving enhanced CSMA / CA which improves channel availability and quality of service (QoS) in a wireless communications network. The system and method establish channels to enable communication between nodes in a communication network, based on the relationship between the average time length of message data packets and the time lengths of the request to send and clear to send messages. A node of the communication network places a data packet at a location in a queue for retransmission based on a type of information contained in the data packet if the destination node for which the data packet is intended is unable to receive the data packet. The location in the queue is indicative of a duration of time that the node will delay before attempting to resend the data packet to the destination node.

A communication bandwidth is divided into a beacon period in which all master stations compete for transmission of a beacon packet, a first carrier sense multiple access (CSMA) period in which only authorized specific stations are allowed to compete for access, and a second CSMA period in which all stations are allowed to compete for access. The master stations exchange information with each other about a communication bandwidth being used in the first CSMA period, thereby calculating a communication bandwidth which can be used by each communication system in the first CSMA period, based on the information.

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 carrier sense multiple access method capable of improving throughput in a wireless network is disclosed. This method is implemented in a wireless network—for example, a wireless LAN (100)—having an AP (110) that is equipped with a multi-beam antenna (111) that forms a directional beam and that is capable of SDMA, and a STA (120, 130, 140) that communicate with the AP (110). With this method, the AP (110) allots the STA (120 to 140) to a beam group defined by a coverage area of the directional beam, according to the location of the STA (120 to 140). Then, the allocated STA (120 to 140) is assigned a signature signal for group identification, the signature signal being unique to the group.

A method and apparatus are described for performing channel aggregation to communicate over a non-contiguous spectrum, such as television white space (TVWS), using a plurality of aggregated channels including a primary channel and at least one non-primary channel (e.g., a secondary channel, a tertiary channel or a quaternary channel). Carrier sense multiple access (CSMA) may be performed on the primary channel to obtain access to the primary channel. After waiting an arbitration interframe space (AIFS) and potentially performing backoff on the primary channel, the aggregated channels may be used for transmission. A buffer controller may be used to create, for each of a plurality of access classes (ACs), a logic buffer for each of the channels. A frame controller may be used to provide the buffer controller with aggregated medium access control (MAC) protocol data unit (A-MPDU) frame information, and control aggregation and fragmentation processes.

The invention relates to a wireless ad hoc network communication method and device. The method sends data to a node through a wireless ad hoc network and receives the data sent by the node through thewireless ad hoc network. Wherein the wireless ad hoc network is a frame structure of a mixed frame of a CSMA / collision avoidance CA and a time division multiple access TDMA through a carrier sense multiple access, In signal processing of LTE transmission link, encoding, diversity control and anti-jamming control are combined. In signal processing of LTE reception link, decoding, diversity controland anti-jamming control are combined, andAdaptive routing algorithm across protocol layer is added to realize centerless multi-hop wideband wireless mesh network. The wireless ad hoc network is a peer-to-peer network, all nodes in the network are equal in status, nodes can join and leave the network at any time, the failure of any node will not affect the operation of the whole network, and theinvulnerability of the network is improved.

The invention discloses a method and a device of remote uderwater acoustic communication. The device comprises more than one underwater communication nodes and more than one abovewater communication buoys which are responsible for communication with more than one underwater communication nodes within a set distance range through an underwater acoustic channel; and the communication connection is carried out between the abovewater communication buoys through a land wireless channel. In the method, the multi-frequency band combination is adopted to sent data in parallel, and the remote communication is realized by uniting the communication buoys; in the remote communication, a three-time handshake protocol in the carrier sense multiple access (CSMA) needs not to be used in the communicationbetween the underwater communication nodes and the buoys, while a channel can be directly monitored in a full frequency range; the data are synchronously sent to the abovewater communication buoys inparallel on each subchannel on the monitored idle channel by utilizing a frequency modulation method; and the data is transmitted by the abovewater communication buoys through a radio wave manner. Bythe method and device provided by the invention, one-time successful transmission probability of the two parties of the communication can be improved, and the anti-interference performance of a system is enhanced.

The invention provides a cross-layer communication method for an OFDM (Orthogonal Frequency Division Multiplexing) link physical layer and an MAC (Media Access Control) layer of an underwater acoustic communication network. Based on the purposes of reasonably allocating channel resources and improving the throughput of the network, the performance of the network is optimized by a cross-layer data interaction method for a physical layer and an MAC layer. The physical layer adaptively adjusts the modulation order, coding rate and frequency diversity order according to an underwater acoustic channel environment, thus realizing data transmission of different rates to adapt to a fast time-varying underwater acoustic channel; the MAC layer adopts an improved CSMA (Carrier Sense Multiple Access ) / CA (Collision Avoidance) protocol, thus improving the retransmission success rate of data packets and reducing the data transmission delay; and the cross-layer design between the physical layer and the MAC layer solves the problems of high packet loss rate and low transmission efficiency caused by fast time variation, long transmission delay and other factors of the underwater acoustic channel, thus improving the throughput of the underwater acoustic communication network and the spectral efficiency of the system.

The invention discloses an electric power data multi-way communication system. The electric power data multi-way communication system comprises a main station terminal, a PLC (programmable logic controller) network, a centralizer and a meter, wherein the main station terminal, the centralizer and the meter are subjected to communication and coupling through the PLC network. The electric power data multi-way communication system further comprises a centralizer end module arranged at the centralizer end as well as a meter end module arranged at the meter end; the centralizer end module is connected with the meter end module through an electric power line protocol. The invention also discloses a multi-way centralized meter reading system. According to the electric power data multi-way communication system and the multi-way centralized meter reading system disclosed by the invention, communication modules are intelligent nodes, and intelligent modules interact for instant networking, and the networking is not controlled by the centralizer; real-time, rapid and stable communication is achieved; the antidamping and noise resistant capabilities of the systems are improved further on the networking mechanism based on a physical layer by fully utilizing the intelligent characteristic of a chip of the physical layer; the technical difficulties of network time and sequence, network conflict, network efficiency, effective detection of repeated data packets and the like are solved based on the chip CSMA (carrier sense multiple access), and the stability and reliability of communication are ensured.