81 results about "Mac layer protocol" patented technology

The invention relates to the technical field of wireless communication and specifically to a broadband wireless ad hoc network MAC-layer protocol method based on TDMA. The method comprises a step 1 of selecting a central control node in a network; a step 2 of enabling each node to send a control signaling at a control time slot thereof, wherein the control signaling comprises a neighbor state table and a time slot distribution table; a step 3 of enable each node to perform monitoring at a control time slot not belonging to the node; a step 4 of when each node acquires the whole-network topological structure information after a little interaction, enabling the central control node to distribute time slots according to the whole-network topological structure by using an improved sequence vertex coloring algorithm; a step 5 of enabling all nodes in the network to determine the service time slots of their own according to the time slot distribution table and to transmit data packets at the control time slots of their own; a step 6 of applying for a requirement at an access time slot if a new node get access to the network or a node is to exit the network; and a step 7 of jumping to the step 2. The method achieves time slot multiplexing and dynamic distribution.

A medium access control method based on wireless multimedia sensor network differentiating service relates to the design of wireless multimedia sensor network MAC layer protocol, and is mainly used for aiming at different services for providing differentiating service. When audio and video information exit in the multimedia sensor network, and simultaneously text information exists probably, different applications require different QoS. Simultaneously the designed MAC protocol is required for aiming at different services for providing differentiating service. Simultaneously the effective utilization of resource is realized in the full network range. The method according to the invention provides the MAC protocol based on the differentiating service of wireless multimedia sensor network, and adopts setting dynamic time slot allocation plan according to service grade thereby obtaining the MAC protocol based on the differentiating service of TDMA. The service lifetime of wireless multimedia sensor network is prolonged and the coordination and service quality of sensor network are increased through dividing a plurality layers of time slot, adjusting the time slot allocation according to service, dynamically adjusting the service grades and adding the dormancy of inactive node.

The invention relates to a method for constructing a protocol data unit (PDU) of a media access layer (MAC layer) of a wireless communication system. The method comprises the following steps: constructing an MAC PDU in different sections, wherein one MAC Sub-PDU comprises four parts, that is, a synchronous code of N bit, an MAC head, an MAC Payload and a cyclic redundancy check code (CRC) of K bit. The invention further relates to an SDU (Service Data Unit) on the MAC layer and control information unit recovery method. By adopting the method, the throughput rate of the system is increased, and the precious shortage resource is saved.

The systems and methods for incorporating an automatic retransmission mechanism into a point to multipoint network MAC layer that does not already incorporate retransmission are provided by virtue of one embodiment of the present invention. For example, the DOCSIS MAC layer protocol developed for data over cable networks may be modified to incorporate an automatic retransmission mechanism. This allows DOCSIS to be applied more effectively to communication channels such as the wireless communication channel.

The invention provides a data transmission method and a terminal. The method comprises the following steps: obtaining a mapping relation between a packet data convergence protocol (PDCP) entity and aradio link layer control (RLC) entity of a target radio bearer of a sending terminal; and after a media access control MAC layer protocol data unit (PDU) is received, determining a target PDCP entityto which data carried by the MAC layer PDU belongs according to a mapping relationship between the PDCP entity and the RLC entity, wherein the target radio bearer is a direct communication link bearerconfigured by the sending terminal or activated with a PDCP repetition function. The receiving terminal acquires a mapping relation between a PDCP entity and an RLC entity of a target radio bearer ofa sending terminal, the mapping relation between the PDCP entity and the RLC entity which are consistent with the sending terminal can be established, thereby ensuring that the target radio bearer of the sending terminal can be correctly received by the receiving terminal, and ensuring the reliability of data transmission in a direct communication mode.

A distributed and opportunistic medium access control (MAC) layer protocol for randomized distributed space-time coding (R-DSTC), which may be deployed in an IEEE 802.11 wireless local area network (WLAN), is described. Unlike other cooperative MAC designs, there is no need to predetermine, before packet transmission, which stations will serve as relays. Instead, the MAC layer protocol opportunistically recruits relay stations on the fly. Network capacity and delay performance is much better than legacy IEEE 802.11g network, and even cooperative forwarding using one relay station. Avoiding the need to collect the station-to-station channel statistics considerably reduces overhead otherwise required for channel measurement and signaling.

The invention provides a multi-channel microwave resource dispatching method in a wireless system of an intelligent light carrier, which mainly relates to the design of a measurement and control (MAC) layer protocol of a WALN network of a radio over fiber (RoF) system with millimeter waves of 60GHz and the dynamic dispatching of light waves and microwave resources in a wireless system of an intelligent light carrier. In order to relieve the influence of the time delay of optical fibers to an RoF WALN network of 60GHz, the invention provides a multi-channel microwave resource distributing method combining frequency-division multiplexing and time-division multiplexing, wherein the multi-channel microwave resource distributing method comprises two special control channels and a plurality of data channels. By the multi-channel design, the influence brought by the time delay of optical fibers in an RoF network is effectively relieved, the throughput of the system is enhanced, and smaller time delay and switching time are ensured. The RoF system of the microwave resource distributing method based on a plurality of channels can be used for carrying out unified dispatching on light waves and microwave resources in the network. Meanwhile, the demand distribution of the resources is also supported, so that the dynamic reconstruction of the network and the high-efficiency utilization of the resources are realized.

A Medium Access Control (“MAC”) Layer protocol and a method for contention resolution using the protocol is provided for networks with multiple priority traffic. The protocol is used where a physical layer connected to a transmission medium uses a carrier modulation scheme with multiple frequencies. Stations on the network that desire access to the transmission medium use a carrier modulation scheme with multiple frequencies. Stations that desire access simultaneously transmit a single frequency selected at random from a set of physical layer frequencies during an open-contention-interval. At the same time, the stations listen to a combined frequency signal and analyzes it for frequency content. The station whose own frequency matches the highest frequency signal in the combined signal gains access to a transmission medium. In the event of a collision, a restricted-contention-interval is used only for the colliding stations. The probability of successful contention resolution increases very rapidly using the restricted-contention-interval. By partitioning the set of frequencies in contiguous ranges, multiple priority classes can be used with the contention method and the MAC layer protocol.

The invention discloses a multi-channel MAC layer data adaptive transmission method for the internet of vehicles, a medium and a system. The method comprises the following steps: channels are dividedinto a control channel and service channels through an MAC layer protocol based on multi-channel operation; a period of the control channel is divided into a broadcast period and a negotiation period;in the broadcast period, a vehicle node acquires vehicle state information sent by a neighbor vehicle node, and performs adaptive adjustment of the total number of MAC frame time slots according to the vehicle state information; the negotiation period adopts a contention type access mechanism, so that the vehicle node negotiates a use right of the corresponding service channel; the frame length of each service channel is determined according to a negotiation result; and the vehicle node in the internet of vehicles transmits service information with high-throughput requirements on the corresponding service channel, and transmits security service information and control signaling information on the control channel. Therefore, the transmission reliability of the security information is improved, the use fairness of the service channels is guaranteed, meanwhile, the channel utilization rate is improved, and the throughput requirements of service information transmission are met.

The invention discloses a centralized internet of vehicle MAC layer combination and collision predicting and preventing method, belonging to the field of VANET. The method permits reuse of a node timeslot beyond two hops, thereby making the timeslot resource more efficient. First, a road side unit (RSU) can access an idle timeslot set in an RSU timeslot broadcast node in each timeslot period, and a new node selects a timeslot to access randomly according to the timeslot set; then the RSU acquires a position, a speed and timeslot use condition of a vehicle in a range through a relay node, so as to predict the possibility that combination and collision occur; and finally, the RSU adjusts timeslot allocation and broadcasts an adjustment result, so as to prevent combination and collision effectively. In the method, timeslot reuse and assistance of RSU help lower the possibility of combination and collision, so as to shorten message delay of the MAC layer and increase throughput. The method can be used as an MAC layer protocol for sending a broadcast message by a node in the VANET.

An apparatus and method for enabling a device-to-device (D2D) communication, despite an identifier (ID) of a target device being unknown are provided. The apparatus may include a target device determining unit to select primary target devices based on relative distance information between a main device and a target device for communication with the main device, and to determine a final target device based on relative distance information between the main device and each of the primary target devices, a transmitter to transmit, to each of the primary target devices, a selection notification message and a relative distance information request message that are generated by the target device determining unit, and a receiver to receive, from each of the primary target devices, a response message corresponding to the selection notification message, and relative distance information used to determine a final target device.

The invention discloses a media access control method based on a WLAN system in an 802.11ac protocol. The method mainly is used for solving the problem of low spectrum utilization rate resulted from overlapped basic service sets. The method comprises that a wireless access point AP invokes a carrier monitoring mechanism on a master channel so as to determine the busy and idle states of the master channel; when the master channel is in an idle condition, the wireless access point and stations STA access the master channel by a distributed coordination functional channel access method; when the master channel is in a busy condition, the wireless access point selects a first channel in non-master channels as a virtual master channel and sends system notice information SNI to the stations in a basic service set in which the wireless access point is located; SNI copies are sent to the other non-master channels; and the stations access the non-master channels on the virtual master channel according to a point coordination functional interframe interval channel access algorithm. According to the method provided by the invention, the non-master channel is utilized fully; the spectrum utilization rate and system throughput are improved; and the method can be used for optimizing the MAC layer protocol in the 802.11ac protocol.

The invention discloses a power control-based wireless MAC (Media Access Control) layer channel allocation method, which belongs to the field of Ad Hoc networks. In a multi-channel Ad Hoc network, two transceivers are used by a network node, of which one is fixedly arranged in a control channel, and the other one jumps between different data channels. An RTS (Request To Send) frame and a CTS (Clear To Send) frame are transmitted at the control channel by using the maximum power; a DATA frame and an ACK (Acknowledgement) frame are transmitted at the data channels by using the minimum power. The minimum power is calculated according to the minimum receiving power threshold which can be correctly received and decoded by a receiving node. The transmitting powers of all nodes in a same collision domain are divided into different grades, and then a corresponding data channel is selected according to the grade of the minimum power, so that links with larger transmitting power difference are allocated to different channels, the adverse effect of asymmetric links in the same channel can be relieved, and the network throughput and the unit energy consumption throughput are improved. The concrete implementation CAPC (Channel Assignment with Power Control) protocol can be used as an MAC layer protocol of the channel selected by Ad Hoc network node equipment.

The invention discloses a wireless media access control (MAC) layer multi-channel dynamic distribution method which belongs to the field of an Ad Hoc network. In the multi-channel Ad Hoc network, node participating in communication form a cell with neighbor nodes, when the nodes in the cell select a communication channel, a current state of neighbor nodes of both parties in communication and a possible channel selection scheme of the nodes are considered. Due to the fact that the situation of channel occupation can reflect the possibilities that the nodes can joint the communication, namely the probabilities that the neighbor nodes start communication, profit which is made by the communication nodes in selection of each channel can be calculated through a backward induction method of the game theory, namely the probabilities of effectively avoiding conflicts, information is transmitted by selecting the channel with the largest profit till the states of the nodes in the cell achieve Nash equilibrium, at the moment, the network achieves the optimal communication state, the largest handling capacity and the smallest packet loss probabilities and delay are achieved. The MAC layer channel dynamic distribution method for the Ad Hoc network can be used as an MAC layer protocol for an Ad Hoc network node device to select the channel.

The invention discloses an energy saving method based on a wireless sensor network MAC (media access control) protocol. The energy saving method aims to solve the problem of energy consumption of sensor nodes. According to the energy saving method, a fuzzy control method is adopted, counters for making statistics on monitored channel busy times are arranged, and network flow is assessed by channel busy times in one turn, so that node energy and network flow change are reflected on operating and hibernating time of the nodes as accurately as possible on the premise that establishment of a complicated mathematical model is not required; a 'handshaking notification' mechanism is adopted for reserving a channel and notifying other nodes of channel occupying time, so that the other nodes hibernate as quick as possible; by the aid of a 'loser delay competition' mechanism, success rate of 'handshaking notification' is guaranteed, and energy saving and high efficiency are given consideration to.

The invention discloses a Linux network card driving controller of a dual-network redundant Ethernet controller. The Linux network card driving controller comprises a system bus protocol control module, a control status register module, a receiving transmission control module, a receiving data buffer zone, a redundant channel switching control module, and a MAC protocol control module. The systembus protocol control module is configured to receive a system bus and is connected with the control status register module and the MAC protocol control module; the control status register module connected with the receiving data buffer zone and the redundant channel switching control module by the receiving transmission control module is used for receiving and sending a GMII interface signal; andthe MAC protocol control module connected with the control status register module and the receiving transmission control module is used for receiving and sending an MII interface signal through a first PHY management module to realize MAC layer protocol control during data communication. According to the invention, the Linux network card driving controller has the high reliability; and accurate and efficient allocation, utilization and recycling of the memory resource buffer zones and descriptors are realized.

The invention provides a device which protects voice over internet protocol in terminal concurrent service, which comprises a first processing entity which is used to execute shifting function for MAC-hs PDU to get MAC-d protocol data unit MAC-d PDU, and execute shifting to the MAC-d PDU when the MAC-d PDU is provided with C/T field, a second processing entity which is used to receive and transmit the processing results of the first processing entity, and process DCH service, when the process of processing shifting of the first processing entity conflicts with the process of process DCH of the second processing entity, the DCH service is firstly processed. The invention firstly process voice over internet protocol through repeatedly diving MAC layer protocol of the UE side into an MACHS entity and MACD entity when HSDPA service and voice over internet protocol are concurrent, thereby guaranteeing conversion quality.

The invention discloses a data transmission method for an MAC layer based on cooperative communication between neighbor nodes in the Internet of vehicles, and belongs to the technical field of vehicular ad-hoc network communication. According to the method, cooperative retransmission is performed on a data packet with the transmission being failed through introducing cooperative nodes in allusionto a phenomenon of multiple times of retransmission performed when the data transmission fails in the existing vehicular network, and the idle time slot in the current time frame is sufficiently utilized, so that the channel utilization ratio is effectively improved. In the cooperation mechanism, the optimum selection nodes are selected by adopting different strategies according to the number of failure nodes, and the establishment of a stable link is ensured to complete the cooperative communication, so that the probability of successful data packet transmission is improved, the time delay isalso reduced, and reliable transmission of data in the network is effectively realized. The data transmission method can be used as an MAC layer protocol for transmitting broadcast messages by nodesin the vehicular network, and is applicable to scenarios with complex network topological structure and low data transmission reliability.

The invention discloses a method for processing node failure in a distributed wireless access system. The method comprises the following steps: after determining that a first network subnode within the self control range has a fault, a network main node utilizes a notification message used for prompting notification message to adjust the network resource by a network layer protocol encapsulation and a notification message based on the protocol encapsulation of an MAC layer and a network layer protocol and transmits the notification messages to other network subnodes which have safety relation with the first network subnode; and after receiving the notification message, the other network subnodes carry out corresponding adjustment to self network resources, utilizes a reply message used for notifying that the adjustment of the network resources is completed by the network layer protocol encapsulation and a reply message based on the protocol encapsulation of the MAC layer and the network layer protocol and returns the notification messages to the network main node. Therefore, when a certain network subnode has a fault, other network subnodes which have safety relation with the network subnode can complete adjustment of the network resources without carrying out protocol conversion, thus simplifying operation process to a certain extent, improving the interoperability of all the network nodes, and further reducing the operation cost of the system. The invention discloses a corresponding communication device and a communication system simultaneously.

The invention relates to an Ethernet MAC module realization device and an Ethernet MAC module realization method used for IEEE 1588v2 protocol. The Ethernet MAC module realization device comprises aMAC receiving module and a MAC transmitting module. The MAC receiving module is used for receiving of all Ethernet messages, and is realized on an FPGA or an ASIC. The MAC transmitting module is for the transmitting of all Ethernet messages, and is also used to return the transmitting time stamps of the Ethernet messages to a PTP protocol stack. The MAC transmitting module is formed by a softwareprogram and a hardware logic. The software program of the MAC transmitting module is installed on a CPU or DSP platform, and is used for PTP time stamp related auxiliary computation and MAC part control function. The hardware logic of the MAC transmitting module can be realized on the FPGA or the ASIC, and is used for PTP time stamp processing, time stamp related part real-time computation, and MAC layer protocol realization. Exchange between the MAC receiving module and the PTP protocol stack, the exchange between the MAC transmitting module and the PTP protocol stack, and the exchange between the software program and the hardware logic of the MAC transmitting module are reduced, and the mutual exchange is required to wait.