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

An improved method of network management, particularly in the context of standards IEEE802.11 and IEEE802.11k, through two new MAC measurements, with attendant advantages. The two new measurements include WTRU uplink traffic loading measurement, and an AP service loading measurement and is generally applicable at least to layers 1 and 2 as applied to a least 802.11k in the context of OFDM and CDMA 2000 systems, but is applicable to other scenarios as well. A Method for determining and advertising congestion is also provided for a Wireless Local Area Network (WLAN) system. The present invention also introduces a method for managing congestion when congestion is detected. This aspect of the present invention applies primarily to wireless systems that use the Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) mechanism. The methods are advantageously implemented in selectively configured WTRUs of various forms.

Provided is a method of dividing a payload intra-frame for improving throughput of a carrier sensing multiple access/collision avoidance (CSMA/CA) wireless communication network. The payload intra-frame dividing method includes a data frame dividing step and a physical layer frame generating step in which a physical layer receives a plurality of data frames from an upper layer within a range of the maximum data frame length the physical layer can transmit and transmits the data frames as a single physical layer data frame. Furthermore, an acknowledge (ACK) frame is provided, which can minimize the deterioration of throughput even when a data frame, which has been divided into a plurality of data frames and transmitted as a single data frame, is required to be re-transmitted because an error is generated in the data frame.

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 method for effectively implementing real time multimedia data transmission in an Ethernet network that operates in a CSMA/CD (Carrier Sense Multiple Access/Collision Detect) scheme. Real time data gets priority over general data, and uses an MPCP (Multi-Point Control Protocol) of the IEEE 802.3ah EPON to prevent a collision from occurring in real time data transmission, and also prevents delay time variation. An RT-IFG (Real Time Inter-Frame Gap) is defined for real time data, shorter than an IFG, to give priority to the real time data over general Ethernet data. The MPCP is used for transmission of real time data without collision between the real time data.

The present invention protocol offers guaranteed Quality of Service (QoS) for a predetermined number of circuits in a highly dynamic, scalable network. The present invention protocol employs a Time Division Multiple Access (TDMA) reservation scheme to transmit deterministic data (e.g., image data) to a destination, while utilizing a Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) contention scheme to support non-deterministic data traffic. The protocol operates over a link-state based routing protocol that reliably floods routing and resource reservation information to the nodes in the network. Moreover, the present invention capitalizes on certain properties of a radio, such as a RAKE type receiver, to enable simultaneous re-transmissions of resource and route reservation information to constructively interfere and enhance the strength and range of the signal.

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.

This invention discloses an adaptive dormancy method for a separated cluster structure radio sensor network data link layer, which starts up the head in network and radio communication devices for collecting nodes to initiate them at the sending or intercepting state, if no data frames are sent or received by the ordinary nodes in the cluster, the device can be turned off to enter into the dormancy state and a carrier intercepting multipath access mode avoiding conflict is applied between the head and ordinary nodes, which puts forward a system that nodes alter the time of dormancy adaptively along with dortmancy times based on binary index and a system of sending cluster head transmission instruction chart management frames periodically by cluster heads, so the radio sensor network can work under single channels asynchronously to ease up the collide and re-tansmission of nodes in the synchronous mode and too many synchronous control signalings.

The invention discloses a time division multiple access/frequency division multiple access (TDMA/FDMA)-based wireless sensor network (WSN) medium access control (mac) layer scheduling method. By the scheduling method, channels are distributed by using a time division multiplex (TDM) system in clusters and a frequency division multiplex (FDM) system among the clusters aiming at a clustering-based data collection type WSN network. The TDM system and the FDM system favorably overcome the defect of a large number of access conflicts of a contention type mac scheduling method under the condition of high network load. Meanwhile, by the novel mac scheduling method, carrier sense multiple access (csma) time slots are introduced at a communication stage in the clusters, so that the defect of low expansibility of the TDMA scheduling methods is overcome. A node revives in an active period to forward data and enters a dormancy state in an inactive period, so that the energy consumption is lowered. According to the conditions of the network load, by the scheduling method, the duty ratio of the active period in the communication cycle can be automatically adjusted, the dynamic requirements of the network on throughput can be met, and the time delay of the data is reduced to a certain extent.

A method and a target node for preventing collisions between networks communicating based on a carrier sense multiple access/collision avoidance (CSMA/CA) scheme, are provided. The method includes synchronizing an object network with a neighboring network. The method further includes allocating, to the object network, a slot index based on a number of the networks, and a contention window (CW) size. The method further includes setting, for the object network, a back-off counter value based on the CW size. The method further includes reducing the back-off counter value based on a channel state of the object network, and the slot index. The method further includes transmitting data related to the neighboring network based on the back-off counter value.

A medium access control method of a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) based wireless LAN (Local Area Network) provides contention-free medium access authority to a station or access point receiving a request signal by: transmitting a request signal frame from an arbitrary station to another arbitrary station or to an access point via a medium occupied in transmission contention with a CSMA/CA algorithm using a DCF (Distributed Coordination Function) interframe space; and transmitting an acknowledgment signal frame from the station or the access point receiving the request signal frame to the station transmitting the request signal frame via an occupied medium using a short interframe space.

The invention provides a networking method of a wireless sensor network. A way of combining carrier sense multiple access (CSMA), time division multiple address (TDMA) and multi-channel technology is mainly utilized for sequentially finishing confirmation of cluster head nodes and overall situation communication time slots of the cluster head nodes, and confirmation of each cluster member node in each cluster and cluster internal communication time slots of each cluster member node, forming time of each cluster is shortened, and therefore fast networking can be achieved. Moreover, a plurality of clusters can communicate on different component channels in the same time period without mutual interference, networking time of the whole network is shortened, delay time of data transmission of each cluster is shortened, the cluster member nodes upload data in the fixed different time slots, and data collision within the clusters does not occur. The feasible networking method is provided for engineering design, and can be applied to the wireless sensor network with densely-distributed sensor nodes.

The invention provides a method for controlling multiple air-conditioned indoor units by using a single wire control device. The method comprises the following steps: (1) connecting wires and sending out an order; (2) receiving the order and analyzing the order; (3) forwarding the order; (4) executing and feeding back; (5) returning an execution result. A control signal can be sent based on a CSMA/CD (carrier sense multiple access/collision detect) protocol, the order of the wire control device can be sent through indoor and outdoor buses, and one single wire control device can control multiple indoor units only by virtue of one connecting wire, thus the installation cost and material cost can be effectively reduced, and the phenomena of chaos communication and mistaken operation caused by control of multiple connecting wires can be avoided.

An apparatus and method for deciding a handover in a dual mode portable terminal supporting a cellular network and an unlicensed ISM (Industrial, Scientific and Medical) band network based on a Carrier Sensing Multiple Access with Collision Avoidance (CSMA/CA) scheme is provided. The method includes checking for an available throughput of an Access Point (AP) by analyzing a signal received from the AP of the unlicensed-band network while using the cellular network; determining whether the AP can provide a service provided through the cellular network by using the available throughput of the AP; and if it is determined that the AP can provide the service, deciding whether to handover to the AP by measuring a strength of the received signal.

An electronic device may be operable to control access to a physical medium (e.g., airwaves, a copper cable, or an optical fiber) utilizing carrier sense multiple access (CSMA). The amount of time that the electronic device must sense the physical medium as being inactive before it permits transmission of a message onto the physical medium may be determined based on: the size of the message, the type of the message, the symbol rate at which the message is to be transmitted, and/or a channel onto which the message is to be transmitted. Similarly, other aspects of how and when electronic device transmits and/or receives on the physical medium may be controlled via one or more dynamically configurable parameters which may be configured based on characteristics of received and/or to-be-transmitted messages.

The invention discloses a wireless communication system, which is provided with a control node and a plurality of user nodes, wherein each user node is provided with respective priority; the user nodes can access a channel in a universal access time period and special access time periods which correspond to the respective priority; in the universal access time period, each user node accesses the channel in a carrier sense multiple access / collision avoidance (CSMA/CA) mode; each special access time period has the corresponding priority; each special access time period can correspond to one or more priorities through system configuration; and when one special access time period corresponds to only one priority, only the user node which corresponds to the priority are allowed to access the channel in the current special access time period.

A method and apparatus for measuring the quality of wireless channels based on a result obtained by measuring contentions between stations in a wireless network employing a carrier sense multiple access/collision avoidance (CSMA/CA) medium access control (MAC) method specified in the IEEE 802.11 standard are provided. The method includes determining contentions between stations to transmit frames via a wireless channel that uses a contention-based medium access method, and measuring the quality of the wireless channel based on the determined contentions.

The invention discloses a visible light local area network duplex communication method and relates to the technical field of visible light communication. In the method, up transmission of data is performed when an access point is turned off; a terminal sends a request frame to the access point at first and sends a data frame after receiving a response frame of the access point; and down transmission of the data is performed when the access point is turned on; and the data to be sent is modulated on light of the access point and broadcast. By the visible light local area network duplex communication method, an uplink and a downlink of a visible light local area network can work in a visible light wave band and two different technologies in the uplink and the downlink can be avoided, so the technical complexity of the local area network is reduced. In the uplink, a carrier sense multiple access/collision avoidance (CSMA/CA) protocol is adopted, so multiple access of the point is realized; and a requesting-authorizing mechanism can be used for distributing an up bandwidth, so hidden stations during wireless communication can be avoided.

Determination of a transmission through a network having a plurality of nodes using carrier sense multiple access collision avoidance (CSMA/CA) may be performed by broadcasting a route request (RREQ) packet from a source node that is targeted towards a destination node within the network, such that the RREQ is received by a first set of nodes in proximity to the source node. After first receiving a RREQ, each of the plurality of nodes rebroadcasts the RREQ after waiting a randomized amount of wait time. During each randomized wait time, the node suppresses all but one RREQ received by the node during the wait time.