91results about How to "Reduce retransmission rate" patented technology

The invention discloses a downlink data transmission method, a downlink data transmission system and downlink data transmission equipment, which relate to the field of wireless communication and are used for improving data transmission reliability and saving air-interface resources. The method comprises that: a base station allocates physical resource blocks (PRB) to a terminal according to channel quality indicator (CQI) information reported by the terminal and the current volume of downlink data to be transmitted; the base station determines a first modulation and coding scheme (MCS) level, wherein the first MCS level is lower than a second MCS level which is an MCS level determined according to signal-to-interference and noise ratios (SINR) on each PRB allocated to the terminal; the base station searches for an MCS form and a transport block size (TBS) form to obtain a TBS corresponding to the first MCS level and the total number of the PRBs allocated to the terminal; and the base station transmits the downlink data of the TBSs to the terminal by utilizing the PRBs allocated to the terminal. By the method, the system and the equipment, the data transmission reliability can be effectively improved, the repeat probability of a hybrid automatic repeat request (HARQ) can be reduced, and the wasting of air-interface resources can be effectively reduced.

Disclosed is a reliable transmission method based on UDP. The transmission features of TCP is combined during UDP transmission, the connection is established through handshake for 3 times and is remained through heart beats, the connection can be broke actively or when the heart beats cannot be received, and a reliable transmission channel for data transmission is established; during data transmission, data are transmitted in a manner of maximum efficiency through a sliding window and a retransmission mechanism. By the aid of the method, the data transmission is more flexible, parameters can be adjusted dynamically so as to be adaptive to different network environments; the adaption range is wider, and the method is adaptive to the P2P network; various network environments adaptive to UPD applicant occasions are optimized greatly, the UDP transmission efficiency is improved, the retransmission rate is decreased, and data redundancy is reduced; when network abnormality occurs, a series of measures are performed, and the quality of network transmission is guaranteed.

The embodiment of the invention discloses a channel quality indication (CQI) adjustment method, user equipment, a base station and a system. The method comprises the following steps of: receiving a signaling message transmitted by the base station through the user equipment (UE); respectively measuring CQI of a relay subframe to obtain a first CQI measured value and measuring CQI of an access subframe to obtain a second CQI measured value; and transmitting the first CQI measured value and the second CQI measured value to the base station, so that the base station performs CQI adjustment on the UE scheduled on the relay subframe according to the first CQI measured value and performs CQI adjustment on the UE scheduled on the access subframe according to the second CQI measured value. Because the CQI can be adjusted according to the CQI of the relay subframe and the access subframe, the throughput of the UE scheduled on the relay subframe can be improved, and the error rate and UE retransmission rate are reduced for the UE scheduled on the access subframe.

The invention discloses a method, a device and a system for processing information. The method comprises the following steps: receiving the data to be sent by layers above a physical layer of an information sending device, using short-code long error correcting codes to carry out error correction coding, and encapsulating the data into code blocks comprising data blocks and check blocks; carryingout cyclic redundancy check (CRC) coding on the encapsulated code blocks by the layers above the physical layer, adding packet head information on the code blocks which are processed by CRC coding, encapsulating into protocol data unit (PDU) data packets, and sending the data packets to the physical layer; after the physical layer receives the PDU data packets, carrying out physical layer coding;and modulating and sending the PDU data packets after physical layer coding. Because the process of short-code long error correcting code coding for the transmitted data information is added for the layers above the physical layer, the reliability and the quality of the data transmission are improved, the probability that the data needs to be retransmitted is reduced, the processing of the systemfor the retransmitted data is reduced, and the resources and the cost of the system are saved.

The invention relates to a high bit-error long time-delay network self-adaptive transmission method based on network coding. A transmitting terminal conducts self-adaptive network coding to transmitted TCP messages according to the magnitude of the flow of a transmission layer and then transmits the coded messages to a receiving terminal. The receiving terminal obtains original messages through network decoding restoration. Since the transmitting terminal conducts redundant coding to the transmitted messages and the receiving terminal can restore the original transmitted messages as long as partial coded messages are received, the impact of high link bit errors on transmission performance is greatly reduced, the transmission protocol throughput is higher, the retransmission rate of the messages is greatly decreased and the transmission performance is greatly promoted. Moreover, since the self-adaptive coding method is adopted, the confidentiality of information is improved. The methodrequires no support from intermediate nodes for transmission, belongs to an end-to-end reliable transmission acceleration method and is compatible with the current popular reliable transmission protocols.

The invention relates to a wireless link protocol RLP frame retransmission method and apparatus, the method comprises following steps: a RLP layer preserves a lost frame sequence number in a time delay caching area, when the received frame sequence number L_SEQ is smaller than the expecting received lower frame sequence number, if no sequence number same as the L_SEQ is in the time delay caching area, so that the received frame in the present is discarded, the sequence number of the lost frame is calculated, and the corresponding sequence number can be preserved in the time delay caching area, meanwhile, the lost frame sequence number before the presetting value is inserted into a negative response NAK list, when the transmitting time is coming, the NAK is transmitted to the opposite terminal RLP layer, the lost frame is required for transmitting; the apparatus comprises a received module, a control module, a time delay caching module, a reordering caching module, an NAK list module and a transmitting module. The invention improves the compatibility of the RLP layer for various application scenes, can ensure that the RLP layer retransmission rate is low and the transmission rate of the RLP layer is constant under the condition of large shake.

The invention discloses a medium access control method based on a CDMA underwater acoustic network for improving the network throughput, shortening end-to-end time delay and reducing the energy consumption so as to prolong the service life of the network. The invention adopts a CDMA access mode and a distributed power control technology, and nodes participating information transmission dynamically adjust data sending power according to network conditions on the premise that the nodes do not influence the normal sending and receiving of adjacent nodes so as to overcome the near-far effect existing in a CDMA system. Meanwhile, the invention improves a handshake mechanism in a traditional medium access control method, uses a data pocket to replace an ACK as a response for successful interaction in case of satisfying special conditions and can obtain higher performance under the conditions of different network loads so as to be effectively applied to reliable data transmission in the underwater acoustic network.

The invention discloses a method and a device for regulating a maximum message size. The method comprises the following steps that: the tolerance upper limit and the tolerance lower limit of a wrong packet rate are preset, wherein the tolerance upper limit of the wrong packet rate is smaller than the tolerance lower limit of the wrong packet rate, a sender aggregates medium access control protocol data units (MPDUs) in a send buffer according to the maximum message size of a current aggregate medium access control protocol data unit (A-MPDU) to obtain an A-MPDU message; the sender transmits the A-MPDU message, after transmission, the wrong packet rate of the message is counted, and when the wrong packet rate is smaller than the tolerance upper limit of the wrong packet rate, the maximum message size of the current A-MPDU is enlarged; when the wrong packet rate is greater than the tolerance upper limit of the wrong package rate, the maximum message size of the current A-MPDU is shortened; and otherwise the maximum message size of the current A-MPDU is kept. By the method, the throughput of a transceiver is increased.

The invention discloses a data transmission method, and communication equipment and system. The method includes the following steps: cooperative equipment and target equipment receive to-be-transmitted data sent by network side equipment, and the time when the target equipment gives feedback to the network side equipment whether the to-be-transmitted data is correctly received is defined as a first moment; before the first moment, the cooperative equipment sends the to-be-transmitted data to the target equipment; and the target equipment receives, processes and verifies the to-be-transmitted data sent by the cooperative equipment before the first moment. Even though the target equipment cannot correctly receive the to-be-transmitted data sent by the network side equipment, the target equipment does not need to request the network side equipment to resend the to-be-transmitted data if the target equipment can correctly receive the to-be-transmitted data forwarded by the cooperative equipment, so that the success probability of the target equipment to receive data can be effectively enhanced, and the probability of retransmission of the network side equipment to the target equipmentcan be reduced.

The invention discloses an uplink competitive access method of a heterogeneous network based on optical communication VLC for mainly solving the problems that the uplink and downlink interference of the VLC technology is serious, the network delay is large, and that the data packet retransmission probability is relatively large. The scheme is as follows: constructing a visible light beacon frame to realize isomerism between VLC and infrared communication; adding busy and idle information of an infrared channel to the visible light beacon frame, and increasing a detectable range of the infraredchannel in a broadcasting manner; judging whether the channel is busy or idle, and executing an improved backoff algorithm; and sending an access request and data after a condition is met, and completing the uplink access of the heterogeneous network based on the optical communication VLC. The invention designs the visible light beacon frame containing infrared channel information, the separationof the uplink and the downlink in an optical communication network can be realized, the mutual interference is avoided, the existing infrared communication backoff algorithm is improved, a nonlinearbackoff function is proposed, the network delay and the data packet retransmission probability are reduced, and the communication is better implemented. The uplink competitive access method is suitable for indoor visible light heterogeneous network communication.

A method and device for transmitting semi-persistent scheduling (SPS) data reduces the probability of retransmitting a semi-persistent service, and increases the system throughput. The method includes: determining an initial transmission carrier for transmitting SPS data according to channel condition information of each carrier in multiple carriers and a gain of a match of a multi-user multiple-input and multiple-output (MU-MIMO) antenna unit; instructing, to a user, the determined initial transmission carrier for transmitting SPS data; and transmitting the SPS data to the user through the instructed initial transmission carrier for transmitting SPS data. The method and device are mainly applied to a process for transmitting SPS data in a carrier aggregation scenario.

The embodiment of the present invention provides a wireless local area network anti-interference method applied to a wireless access system composed of a plurality of wireless access points (AP) which are deployed based on a fixed spacing row-column matrix. The method comprises the following steps of obtaining the signal intensity indication RSSI value of each AP received by other AP during a message sending process; according to the RSSI value, adjusting the current sending power of each AP; according to the RSSI value and the current sending power, adjusting the energy detection CCA threshold value of each AP; after the current sending power and the CCA threshold value are adjusted, indicating each AP to adjust the sending speed, so that each AP sends a message according to the adjusted sending speed. Meanwhile, the present invention also provides a wireless local area network controller. According to the present invention, the throughput of a wireless local area network under a dense deployment environment is improved.

The invention discloses a space coupling based LDPC code HARQ retransmission mechanism, and belongs to the technical field of error control. A receiving end stores old code sequences failed in transmission in a buffer; a transmitting end constructs a coupling basis matrix and generates a coupling extension verification matrix, codes the old information sequences failed in transmission and to-be-transmitted new information sequences after being subjected to splicing so as to obtain new code word sequences, stores the new code word sequences in the buffer after the punching positions of the old information sequences and the new information sequence are removed from the new code word sequences, and then selects a code sequence with a certain length and transmits the code sequence through a channel; and the receiving end decodes the received code sequence and the old code sequences in the buffer by utilizing the coupling extension verification matrix and an old decoding verification matrix. By utilizing the error correction performance and retransmission chance of the newly transmitted sequences to restore the sequences failed in transmission in an IR-HARQ mechanism, the space coupling based LDPC code HARQ retransmission mechanism can reduce the ARQ retransmission probability and system delay and can improve the throughput of the system while improving the reliability of a communication system.

The invention relates to a mobile ad-hoc network (MANET) congestion control method based on an OLSR protocol and belongs to the field of wireless network routing protocols. According to the method, by means of a regular broadcast updating function of a route table between neighbor nodes, standby forwarding nodes are selected through a channel occupancy rate such that more forwarding nodes of a specific target node are obtained, thereby dispersing forwarding paths and reducing congestion degree in a network. Only one channel occupancy rate item is added when the route table is broadcasted such that the method has very low burden on a whole system and is easy to be implemented in practical application. The method may acquires the topological structure and the node information of the network in real time, and updates the forwarding nodes in the route table in real time according to the channel occupancy rate, guarantees normal control of the whole network, and prevents congested points and flooding broadcast, and is suitable for wireless MANETs using the OLSR protocols and wired networks using the OLSR protocols.

The invention discloses a multi-carrier feedback information sending system, which comprises a setting unit, a sending unit and a selecting channel, wherein the setting unit is used for setting mapping relationship among feedback information, channel selection and modulation symbols according to feedback requirements on downlink component carriers; the sending unit is used for obtaining the mapping relationship from the setting unit; and the selecting channel sends the feedback information according to the mapping relationship by adopting the modulation symbols corresponding to the channel selection and the feedback information. The invention also discloses a multi-carrier feedback information sending method, which comprises the following steps: setting the mapping relationship among the feedback information, the channel selection and the modulation symbols according to the feedback requirements on the downlink component carriers; selecting the channel by a sending side and sending the feedback information according to the mapping relationship by adopting the modulation symbols corresponding to the channel selection and the feedback information. By adopting the system and the method, the adopted and set mapping relationship can be regulated according to actual feedback requirements, thus improving the feedback performance of the feedback information under a plurality of the component carriers.

The invention provides a demodulation method and a demodulation device for downlink data, and a terminal. The demodulation method for the downlink data comprises the following steps of receiving first exclusive downlink control information, second exclusive downlink control information and downlink data which are sent by a base station when the terminal is scheduled in a target first-class TTI; detecting whether the second exclusive downlink control information can be demodulated correctly; determining actual downlink control information needed by the terminal according to the first exclusive downlink control information and the target second exclusive downlink control information when the second exclusive downlink control information cannot be correctly demodulated, wherein the target second exclusive downlink control information includes second exclusive downlink control information which is correctly demodulated in a process of scheduling the terminal by at least one first-class TTI; and demodulating downlink data based on the actual downlink control information. Through the technical scheme of the invention, the probability of sTTI data retransmission can be reduced and the unnecessary additional time delay can be avoided.

The invention provides an uplink transmission method, a station, a communication system, and a management real object. The method comprises a step that a station STA generates an uplink frame which comprises RUT (robust uplink transmission) indication information. When the value of the RUT indication information is a first value, it indicates that an associated access point A-AP associated with the station STA and a coordinative access point C-AP in coordinative relation with the associated access point A-AP receive the uplink frame and carry out the RUT processing of the uplink frame; when the value of the RUT indication information is a second value, it just indicates that the associated access point A-AP associated with the station STA receives the uplink frame and carries out the non-RUT processing of the uplink frame. The method also comprises a step that the station STA transmits the uplink frame.

The invention provides a method for allocating time slot resources, which comprises the following steps: a base station allocates time slot resources needed by UE (user equipment) in a current scheduling period; when rest time slot resources which are not allocated exist in the current scheduling period and no new UE needs scheduling in the current scheduling period or the rest time slot resources cannot be scheduled because of lack of configured quantity of HS-SCCHs (high speed signaling control channels), the base station allocates the rest time slot resources to the UE which is currently scheduled according to a preset strategy; and the base station informs the corresponding UE of the allocated rest time slot resources through the HS-SCCHs, so that the UE can carry out data transmission according to the allocated rest time slot resources. With the adoption of the method, the code rate can be lowered, the probability for data retransmission is reduced, the service rate is increased, and the throughput of a system is enhanced.

The invention discloses an NDN (Named Data Networking) interest packet reliable transmission method in a wireless scene and belongs to the technical field of communication. According to the method, redefinition of measurement of RTT (Round Trip Time) is taken as the basis of setting a timeout retransmission timer, after a downstream node forwards an interest packet, the timeout retransmission timer is started, and after an upstream node receives the interest packet, the upstream node processes or forwards the interest packet and replies an acknowledgement message to the downstream node, so aninterest packet response mechanism is realized. If the downstream node receives the acknowledgement message before the timeout retransmission timer expires, the downstream node learns processing information of the upstream node for the interest packet and link condition according to the acknowledgement message; and if the downstream node does not receive the acknowledgement message before the timeout retransmission timer expires due to a link fault, the downstream node decides whether the directly transmit the interest packet at a current node or not, so transmission reliability of the interest packet is improved. The method is characterized by that accurate RTT measurement, and low delay and high efficiency because that the interest packet is directly retransmitted at a packet loss position. The method is applicable to a wireless transmission environment in which a link is instable and an interest packet retransmission rate is high.

The invention relates to a secure communication method for messages of a double loop field bus in a numerical control system. The method comprises the following steps: determining a master station and slave stations, dividing a transmission channel into a loop 1 and a loop 2, and determining the station numbers of all the slave stations; respectively packaging original effective data of the master station and associated data used for recovery into an original information security message and an associated information security message, sending the original information security message to all the slave stations through the loop 1, sending the associated information security message to all the slave stations for CRC (cyclic redundancy check) through the loop 2, if the check message is correct, selecting useful data from the message and packaging the checked right response message into the associated information security message for continually sending along the loop 2 till the master station, and meanwhile continually sending the original information security message along the loop 1 from the current slave station to the last slave station; and carrying out the CRC on the received response message by the master station, if the message is correct, finishing the communication. The method provided by the invention has the characteristics of strong real-time performance, high redundancy, low retransmission probability and the like.

A Base Station (BS) antenna in a mobile communication system is provided, in which a reflective plate has a frontal surface onto which radiation elements are attached, and at least one protector is attached onto the reflective plate, surrounding at least part of the reflective plate.

The invention provides a method for reducing transmission control protocol (TCP) message loss in a space information network. According to the method, data packet loss can be effectively reduced, link throughput can be improved, and unnecessary retransmission of a transmitting end in case of link disconnection is prevented. The method is implemented as follows: a transmitting storage module is added at a transmitting end of the TCP; according to a known motion track of a man-made satellite and a predictable characteristic of link disruption due to celestial body blocking, a communication time sequence PAB (t) between any nodes A and B is pre-arranged in the space information network with a node motion rule that can be followed, wherein when PAB (t) is equal to 1, nodes A and B are in a link communication state at the time t, when PAB (t) is equal to 0, nodes A and B are in a link disconnection state at time t; while the network operates, for any time t0, a sending node A firstly verifies the value of PAB(t0), if PAB (t0) is equal to 1, a data packet is sent to a target node B; and if PAB (t0) is equal to 0, the data packet is cached in the storage module of the TCP, and the cached data packet is extracted from the cache and is recovered and sent at next time when PAB (t) is equal to 1 and t is equal to t1.

The invention provides a hydroacoustic media access control method based on a reservation scheduling mechanism. After a fixed node with a data transmission requirement receives an ND packet of a Sinknode, an RTS packet is sent to the Sink node for carrying out data transmission reservation; and the Sink node calculates information of propagation delay and the like according to information in theRTS packet, and then calculates data transmission time of each node, so that data transmission scheduling of each node is completed. The conflict problem of the data packets is effectively avoided based on the reservation scheduling mechanism, the handshaking time between the nodes is shortened, the channel utilization rate is obviously improved, and the data transmission efficiency is improved; and in addition, the nodes do not need to be subjected to time synchronization in advance, so that the implementation requirements of a hydroacoustic communication network are remarkably reduced.

Embodiments of the invention provide a downlink data transmission method and a backhaul base station, relating to the technical field of communication and solving a low reliability problem of data transmission in the prior art. According to the transmission method, the backhaul base station receives downlink data that is sent by a core network and is to be sent to a destination base station; if aCQI regulation condition is met, a second CQI index value is determined according to a first CQI index value of a wireless backhaul link fed back by the destination base station, wherein a modulationorder of a modulation manner corresponding to the second CQI index value is lower than a modulation order of a modulation manner corresponding to the first CQI index value, and the CQI regulation condition includes: the use condition of current wireless resource of the backhaul base station is lower than or equal to a load threshold, and the first CQI index value is within a preset range; a firstMCS index value is determined according to the second CQI index value, and the first MCS index value is sent to the destination base station; and downlink data is sent to the destination base stationaccording to the first MCS index value. The method is applied to downlink data transmission.

The invention provides an access point and an access point management method and system. The access point management method comprises terminal filtering detection, wherein the terminal filtering detection comprises: obtaining at least two communication index values of any terminal connected to the access point for the detection, and calculating a communication value of the terminal according to the communication index values; determining a terminal having the minimum communication value in all terminals; and disconnecting the connection of the terminal having the minimum communication value with the access point. The terminal filtering detection further comprises: setting an effective range of the communication index for each communication index; and when detecting that one communication index value of the terminal is not within the effective range of the communication index, disconnecting the connection of the terminal with the access point. The access point management method provided by the invention can be used for filtering those terminals having high error rates, high retransmission efficiency and very poor wireless transmission efficiency, namely user terminals having very small communication values, and retaining high-quality network users, in order to improve the transmission efficiency of a wireless network.

A reliable multicast routing method in an SDN scene comprises the steps of determining an optimization target, and then establishing a logic network topological graph based on an actual network; establishing a multicast tree according to the logic network topological graph based on the actual network; and recovering node selection in the established multicast tree. According to the invention, efficient routing of one multicast tree and selection of multicast transmission recovery nodes can be realized at the same time. When the multicast tree is constructed, the link resource consumption and the time delay requirement are considered at the same time, and finally the multicast tree which is low in cost and meets the end-to-end time delay requirement is obtained. To support reliable transmission in multicast, a selection of a multicast transmission recovery node is determined. According to the method, the routing of the multicast tree and the selection problem of the recovery node are considered at the same time, so that the sum of the resource consumption of the multicast tree and the resource consumption of the recovery node is minimized, the retransmission probability of the data packet is reduced, and the data transmission delay is effectively reduced.

The invention provides a distributed resource scheduling method in the Internet of Vehicles, and aims to reduce the time delay of an Internet of Vehicles system and improve the reliability of the Internet of Vehicles system, and the implementation steps are as follows: 1) constructing the Internet of Vehicles and a resource pool; 2) initializing a service cache queue of each vehicle Va; 3) updating the service cache queue by each vehicle Va; 4) enabling each vehicle Va to determine a scheduling target business set and parameters thereof; (5) enabling each vehicle Va to obtain a scheduling target single subframe resource set through the communication device Xa; (6) enabling each vehicle Va to determine the transmission target frequency of a scheduling target service Sam; (7) enabling each vehicle Va to determine the upper limit of the occupied target single subframe resource quantity required by single transmission of the scheduling target service Sam; (8) obtaining a distributed resource scheduling result in the Internet of Vehicles.

The invention belongs to the technical field of wireless communications and particularly relates to a wireless transmission method and a network. The wireless transmission method is characterized in that a wireless transmission network is partitioned, different partitions are respectively arranged as a transmission partition and a standby partition, different sleep scheduling strategies are divided for each partition by adopting a sleep scheduling mechanism; in the data transmission stage, nodes in the same partition adopt a probability forwarding mechanism to select a proper node for concurrent transmission in the partition; and the data is transmitted from the partition where an initial node is located until an end node successfully receives the data. By adoption of the method, low energy consumption and low delay of data transmission can be achieved on the strip wireless sensor networks. The method is particularly suitable for application to the strip wireless sensor networks needing low delay and low energy consumption.