304 results about "Clear to send" patented technology

Provided is a method for managing resource in a high capacity wireless communication system capable of communicating with two or more users in a multi-input multi-output (MIMO) scheme when a base station transmits data. The includes: transmitting a MU-MIMO request-to-send (RTS) message to stations intending to transmit data in the MIMO scheme, and sequentially receiving a clear-to-send (CTS) message from stations intending to receive the data; transmitting a transmission ACK message to the stations, wherein the transmission ACK message includes information which prevents data collision during a time of data transmission to the stations and ACK signal; and configuring data to be transmitted to the stations into aggregated packets (A-MPDUs), transmitting the A-MPDUs to the stations in the MIMO scheme, and receiving a block ACK message from the stations.

A communication device and method are provided for communicating with a receiving device over a channel within a mobile ad-hoc network. The receiving device includes a clear-to-send (CTS) packet generating portion that can generate and a CTS packet based on a parameter of the channel and that can transmit the CTS packet over the channel. The communication device includes a transmitter portion, a receiver portion and a management portion. The transmitter portion can transmit information into the channel. The receiver portion can receive information from the channel. The management portion includes a request-to-send (RTS) packet generating portion, a CTS packet receiving portion, a threshold database, a comparator and an RES packet generating portion. The management portion is in communication with the transmitter portion and the receiver portion. The RTS packet generating portion can generate a RTS packet and can provide the RTS packet to the transmitter portion. The transmitter portion can transmit the RTS packet to the receiving device by way of the channel. The receiver portion can receive the CTS packet from the receiving device by way of the channel and can provide the CTS packet to the CTS packet receiving portion. The threshold database can store a threshold value for the parameter of the channel and can provide the threshold value to the comparator. The CTS packet receiving portion can provide channel parameter information, to the comparator, based on the CTS packet. The comparator can compare the threshold value and the channel parameter information and can generate an instruction signal based on the comparison. The RES packet generating portion can generate an RES packet based on the instruction signal and can provide the RES packet to the transmitter portion.

A communication system for carrying out data communication among a plurality of communication stations is disclosed in which a first communication station for transmitting to other communication stations a Request To Send (RTS) signal for requesting a transmission upon the start of the data transmission; and a plurality of second communication stations transmitting to other communication stations a Clear To Send (CTS) signal for notifying the completion of preparing the reception, wherein the first communication station transmits the RTS signal describing at least each of addresses the second communication stations that are desired to receive the data, and receives a plurality of CTS signals transmitted from each of the second communication stations in order to increase communication capacity.

Embodiments of the present invention include a wireless access method based on a NAVT (Network allocation vector table), which is applied to a distributed wireless mobile communication system comprising a plurality of nodes, the NAVT comprises a packet type field and a duration field and is stored in the respective nodes of the communication system, comprising: on a transmitting side, determining whether only a RTS (request to send) item is contained in the NAVT when a packet arrives; sensing channel to judge whether the channel is busy after determining that only the RTS item is contained in the NAVT; sending a RTS packet based on the RTS item to the receiving side after determining that the channel is busy; and on a receiving side, determining whether the NAVT is empty or not when the RTS packet is received; sending a CTS (clear to send) packet back to the transmitting side after determining that the NAVT is empty.

A medium access control (MAC) protocol is provided for avoiding collisions from stations (STAs) comprising two or more IEEE 802.11 basic service sets (BSSs) collocated and operating in the same channel during contention free periods (CFPs). The MAC protocol includes hardware / software for utilizing ready-to-send (RTS) / clear-to-send(CTS) exchange during CFPs to avoid potential collision from STAs in overlapping BSSs and hardware / software for providing overlapping network allocation vectors (ONAV) in addition to a network allocation vector (NAV), the ONAV included to facilitate the effectiveness of the RTS / CTS during CFPs.

A method and system for reliable multicasting on a communication network includes sending Request-to-Send (RTS) signals from a sender node of the network to the receiver nodes, the RTS signals include a set of identifiers corresponding to the receiver nodes. The Clear-to-Send (CTS) signals and Acknowledgment (ACK) signals are sent from the receiver nodes according to an ordering function of the set of identifiers.

Systems and methodologies are described that facilitate mitigating a hidden node condition in a wireless mesh network wherein nodes utilize a request-to-send / clear-to-send (RTS / CTS) protocol in conjunction with an asynchronous hybrid automatic repeat request protocol. For instance, a node may contend for a set of subcarriers by sending an RTS signal over the desired subcarriers, and may receive a CTS signal over the contended subcarriers, wherein the CTS signal indicates which subcarriers the node may transmit data over. If another node has won the contention for a particular subcarrier, requesting node may adjust a power level at which it transmits an RTS or a data packet in order to permit the requesting node to utilize the subcarrier without interfering with the winning node.

A method for providing priority access to 802.11 endpoints. The method includes the steps of sending a Clear To Send (CTS) frame from a designated station, without requiring a Request to Send (RTS) frame from a first station. The CTS frame includes a field identifying the first station for commencing transmission, and a field indicating a duration of transmission. A deferring step is also performed for deferring any transmissions of stations other than the first station until after the duration indicated in the CTS frame has passed.

A method for closed loop link adjustment based on a Request To Send-Clear To Send (RTS-CTS) channel access scheme includes the following steps. Designating a station as an originating station. Transmitting a RTS frame with predetermined transmit power from an originating station, prior to an intended DATA transmission, sounding the channel such that reception characteristics can be evaluated at a designated receiving station. Transmitting, in response to the originating station, a CTS frame with a predetermined transmit power from the receiving station with directives of link adjustments. Transmitting a DATA frame from the originating station to the receiving station frame complying with link adjustment directives to the extent of the originating stations capabilities. And, transmitting an acknowledge (ACK) frame in response to the originating stations from the receiving station indicating result of DATA frame reception.

A channel access method for a very high throughput (VHT) system using a bonding channel having a plurality of subchannels is provided. The method includes receiving training information comprising a training offset value through a subchannel, performing channel estimation on a full channel bandwidth comprising all subchannels when a time corresponding to the training offset value is elapsed after the training information is received, transmitting a request to send (RTS) frame to a destination station through some subchannels selected from the plurality of subchannels by one or a plurality of source stations according to a result of the channel estimation, and transmitting a clear to send (CTS) frame to one source station selected from the plurality of source stations by the destination station in response to the received RTS frame. Accordingly, an effective channel access mechanism is provided for the VHT system, and collision among stations can be avoided.

Embodiments of the present invention include a wireless access method based on a NAVT (Network allocation vector table), which is applied to a distributed wireless mobile communication system comprising a plurality of nodes, the NAVT comprises a packet type field and a duration field and is stored in the respective nodes of the communication system, comprising: on a transmitting side, determining whether only a RTS (request to send) item is contained in the NAVT when a packet arrives; sensing channel to judge whether the channel is busy after determining that only the RTS item is contained in the NAVT; sending a RTS packet based on the RTS item to the receiving side after determining that the channel is busy; and on a receiving side, determining whether the NAVT is empty or not when the RTS packet is received; sending a CTS (clear to send) packet back to the transmitting side after determining that the NAVT is empty.

A method and apparatus of transmitting a multicast frame in a wireless communication system is provided. The method comprises transmitting a request to send (RTS) frame to stations (STAs) included in a multicast group by using an omni-directional antenna, and receiving a clear to send (CTS) frame transmitted by the STAs included in the multicast group in response to the RTS frame, and transmitting the multicast frame to the STAs included in the multicast group by using a directional antenna.

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.

Systems, methods, and instrumentalities are provided to implement transmission scheduling. A multiband device may send a request via a first frequency band. The request may include a multiband Request to Send (MRTS) transmission. The request may be associated with a second frequency band and / or a heamforming training schedule. The first frequency band may be associated with a quasi-omni transmission and the second frequency band may be associated wiih a directional transmission. The first frequency band may be a 5 GHz band and the second frequency band may be a 60 GHz band. The multiband device may receive a multiband Clear to Send (MCTS) transmission via the first frequency band confirming the request. The multiband device may be configured to send a beamforming signal in accordance with the request, for example, via the second frequency band. The beamforming signal may be sent in accordance with a beamforming training schedule.

A method for controlling transmit power of a node in wireless network, such as, e.g., an ad-hoc wireless network operating in accordance with a carrier sense multiple access (CSMA) protocol and where asymmetrical radio links may exist. During a request to send (RTS) and clear to send (CTS) exchange between a first node and a second node, both a request to send (RTS) packet and a probing request to send (PrRTS) packet are transmitted from the first node to the second node. The transmit power and data rate of the PrRTS packet may be different from the transmit power and data rate of the RTS packet. In response, the second node returns a CTS packet that includes a signal to noise ratio (SNR) for both the RTS packet and the PrRTS packet. A correction factor for data transmit power is then computed based in part on both the SNR for the RTS and the SNR for the PrRTS, and a data packet is thereafter transmitted at a power level that has been modified in accordance with the correction factor. The correction factor may further aid the estimation of the signal-to-noise-and-interference ratio (S / (N+I)) at a receiving node, which enables a sending node either to overcome the interference by adjusting the transmit power or avoid the interference by not accessing the channel until it hears the node again.

The present invention discloses systems and methodologies that facilitate coordinating and conducting transmissions to multiple stations in a wireless communication system during a single transmission opportunity. A holder of a transmission opportunity can communicate a request-to-send message or a self-addressed clear-to-send message to one or more stations to establish the transmission opportunity. Subsequently, data transmissions with respective stations can be initiated by transmitting request-to-send messages to the respective stations. At each receiving station, the source address of a received request-to-send message is compared to the address of the holder of the transmission opportunity. If the addresses match for a given request-to-send message, the receiving station transmits aclear-to-send message to the holder of the transmission opportunity in response to the request-to-send message.

In a wireless network system comprising a wired backbone network, an access point, and one or more associated wireless unit data coupled to the access point by way of a wireless transmission medium, a method of enabling fragmentation of data packet above a fragmentation threshold in one or more wireless units, comprising transmitting a message to the one or more wireless unit having a first control data that causes the one or more wireless units to implement fragmentation threshold in transmitting data packets to the access point. The message is preferably a multicast data packet intended for the one or more associated wireless units. The message may further include a specified fragmentation to be used, and also another control signal for enabling request to send (RTS) and clear to send (CTS) transmission by the one or more wireless units.

A pair scheduling medium access control method used in a wireless network, comprises the steps of: checking, by a receiving node, whether a transmitting node has data packets to be subsequently sent, according to data packets received from the transmitting node; when the transmitting node has no data packets to be subsequently sent, checking whether the receiving node has data packets to be sent to the transmitting node or not; if the receiving node has data packets to be sent to the transmitting node, then adding a time period required for sending the data packets of the receiving node into an acknowledgement packet to be sent to the transmitting node; after the receiving node receives a Clear to Send packet sent from the transmitting node, sending the data packets in the receiving node to the transmitting node.

Three or more nodes, each with a plurality of antennas, communicate by transmitting messages simultaneously to each other. One of the nodes transmits two messages to two different destination nodes using different sets of its antennas. A receiving node receives at least two of the messages as a received signal, and uses a spatial demultiplexing algorithm such as VBLAST to extract from the received signal at least one message for which the receiving node is a destination node. Before the messages are transmitted, it is decided how many of its antennas each node is allowed to use to transmit each of its messages. For that purpose, the nodes exchange RTSs (Request To Send messages) and CTSs (Clear To Send messages). Collisions among the nodes are resolved. A transmission power and a route are selected for each message.

A channel assigning method for ad-hoc networks, which uses an intra-cluster bandwidth reserving procedure, including six phases of reservation request RREQ, reservation response RRSP, code assignment CASN, code conflict detection CCD, code conflict report CCR and code confirmation CCFM, and an inter-cluster RTS-CTS (request to send-clear to send) dialogue protocol to generate a TDMA time slot and select an assignment code, thereby supporting real-time traffic and associated QoS guarantee in a multi-hop ad-hoc network.

The invention discloses a carrier sense method and a system. According to the method, a transmitting terminal sends an idle channel to assess clear channel assessment (CCA) request frames on a main channel of a transmission channel which needs to be detected; the transmitting terminal sends request to send (RTS) frames on the transmission channel which needs to be detected after sending a point coordination function inter-frame space (PIFS) subsequent to transmission of the CCA request frame; and the transmitting terminal performs data transmission on the transmission channel transmitting clear to send (CTS) frames after receiving an indication that CTS frames are permitted to send. The invention also discloses the carrier sense system, which comprises a transmitting terminal and a receiving terminal. According to the method and the system, the power consumption of the receiving terminal is reduced and reliable CCA results of all transmission channels are provided.

Methods and apparatuses are related to multi-user parallel channel access (MU-PCA). For example, a wireless transmit / receive unit (WTRU) is provided that is one of a plurality of WTRUs operable to simultaneously communicate via a plurality of channels managed by an access point (AP). The WTRU includes a receiver configured to receive, from the AP, over at least one channel of the plurality of channels, a group request-to-send (G-RTS) message that includes a resource allocation that indicates at least one assigned channel for the WTRU; a transmitter configured to transmit a clear-to-send (CTS) message, to the AP, over the at least one assigned channel of the plurality of channels; and the receiver further configured to receive a data message, from the AP, over at least one channel of the plurality of channels.

Disclosed is a protocol for transmitting data through cooperation between access points in an overlapped basic service set (OBSS) environment. A cooperative beamforming communication method may include negotiating, by a first access point, a cooperative transmit beamforming with a second access point having an OBSS area with the first access point; transmitting, by the first access point, a clear-to-send (CTS) to the second access point; and performing, by the first access point, the cooperative transmit beamforming with the second access point during a cooperative transmit beamforming duration determined through the negotiation after a predetermined time interval is elapsed, when transmission of the CTS is completed.

According to an embodiment of the present invention, a channel access method in a very high throughput (VHT) system using a bonding channel consisting of a plurality of subchannels is provided. Wherein the Method comprises: transmitting a request to send (RTS) frame by one source station or each of a plurality of source stations to a destination station through any subchannel selected from the plurality of subchannels; and in response to the received RTS frame, transmitting a clear to send (CTS) frame by the destination station to one source station selected from the plurality of source stations through the bonding channel.

Systems and techniques for managing the use of industrial-scientific-medical bands for cellular network communication. An apparatus comprises a processing system and a memory storing a set of program instructions. The processing system is configured to cause the apparatus to receive channel information from a UE reporting the control of an industrial-scientific-medical (ISM) band channel by the UE and cause the apparatus to schedule a communication session with the UE over the channel, with the channel being configured and activated as an ISM secondary component carrier (SCC). The apparatus may further request one or more user equipments (UEs) to report their wireless fidelity (WiFi) capability and request user equipments having WiFi capability to compete for the wireless medium and report occupation of the wireless medium in the form of a request to send command, to which the apparatus responds with a clear to send command.

A setting unit sets a specified time serving as a clear-to-send time, during which a two-way frame transmission is possible between a local wireless base station and a wireless terminal station accommodated in the wireless base station, and as a wireless-channel reservation time used for a frame transmission between the wireless base station and the wireless terminal station, and wireless terminal station specifying information for specifying a wireless terminal station to which the specified time is applied, in a transmission control frame. A transmitting unit transmits the transmission control frame to the wireless terminal station.

A communications network which is capable of effectively and efficiently handling fading between mobile wireless user terminals of a packet-switched network with minimal overhead and packet loss, and a method for using the same. The communications network employs an origination mobile terminal and surrounding macroscopic mobile terminals and / or surrounding fixed infrastructure. Communication is established between the origination mobile terminal and surrounding macroscopic mobile terminals and / or surrounding fixed infrastructure. The communication is established via modified request to send (RTS) and clear to send (CTS) messages, wherein the modified messages provide for an additional two sets of k unicast addresses where k equals the maximum number of routes available per route entry in the origination mobile terminal's route table.

A method and an apparatus are provided for enabling a legacy station to perform virtual carrier sensing when a plurality of stations with heterogeneous capabilities coexist in a wireless network. The method includes receiving first data via a bonded channel formed by channel bonding first and second adjacent channels, and transmitting second data via each of the first and second adjacent channels, the second data being a clear-to-send (CTS) frame or a request-to-send (RTS) frame.