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

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 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.

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 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 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 present invention relates to a data transmitting method using power detection of an adjacent channel. The method comprises detecting power for a selected channel; determining an occupancy state of the channel by comparing the detected power with a threshold power; detecting power for a channel adjacent to the channel if the channel is in an unoccupied state on the basis of the determined result; determining a state of the adjacent channel by comparing the detected power for the adjacent channel with the minimum threshold power and the maximum threshold power; and transmitting data by using the channel on the basis of the determined results.

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.