280results about How to "Reduce the number of retransmissions" patented technology

The invention discloses a method and system for identifying reasons of ZigBee sensor network packet loss. The method includes the steps that a receiving node carries out high-frequency sampling on corresponding receiving signal strength information and link quality information while receiving a data package; if the received data package fails to pass the cyclic redundancy check, collision mode fragments possibly existing in the high-frequency sampled receiving signal strength information and the high-frequency sampled link quality information are searched, and the modes monitored in the receiving signal strength information and the link quality information will be regrouped into a time-ordered mode sequence; the receiving node searches for the generated mode sequence and outputs the packet loss reasons of the damaged data package by using corresponding identifying rules; the receiving node adds the specific reasons of data package loss in an acknowledgment packet sent to a sending node. Through the method, network throughput can be improved and retransmission frequency can be reduced, so the purposes of saving energy and prolonging working time can be achieved.

The invention provides a narrowband Internet of Things NB-IoT random access method based on the non-orthogonal technology. The narrowband Internet of Things NB-IoT random access method is applied to anarrowband Internet of Things random access method and is used for solving the problem of low random access success rate. The method comprises the following steps: 1-3, sending Msg1; 4, detecting, bya base station, multi-preamble of collision based on geographical distribution and transmitting RAR (that is, Msg2) with multiple users; 5, detecting, by a terminal, RAR; 6, estimating, by a user, TAby using an NPRS signal; 7, obtaining, by the user, RAR information, searching a TA value closest to the TA of the current user in the RAR, and obtaining corresponding Temp C-RNTI and Power BO; 8, transmitting Msg3, and opening a contention resolution timer CR; 9, separating the users based on the SIC technology; and 10-11, sending Msg4, and performing conflict resolution. According to the narrowband Internet of Things NB-IoT random access method, the multi-preamble detection and RAR reception are achieved by using the spatial distribution features of the user, the Msg3 is transmitted by using the non-orthogonal technology, the user separation is performed on the base station side, thereby effectively reducing the probability of preamble retransmission, improving the system capacity, andsolving the network congestion problem caused by large-scale connection of the NB-IoT system.

An adapting method of channel includes carrying out estimation on state of current channel by user terminal for obtaining CQI data, adjusting CQI data according to preset revision parameter and sending adjusted CQI data to base station, selecting modulation coding mode by base station according to adjusted CQI data and send data to user end. The device used for realizing said method and another adapting method of channel are also disclosed.

The invention discloses a signal retransmission method based on the hybrid automatic repeat request (HARQ) technique in an orthogonal frequency division multiplexing (OFDM) system, which belongs to the field of wireless communication systems. The method comprises the following steps: firstly a transmitting terminal receives the re-transmission information from a receiving terminal, and then the transmitting terminal increases the density or intensity of a pilot signal in a transmission-side memorizer and then retransmits the signal. The signal retransmission method increases the signal transmission quality and the retransmission reliability of the broadband wireless communication system during the retransmission process, thereby reducing the retransmission frequency of the wireless communication system and saving time resources.

The invention relates to a wireless reliable broadcasting method based on a random linear network code. The wireless reliable broadcasting method comprises two stages: broadcasting an original data packet and retransmitting a coding packet, namely, performing a linear network code on a lost data packet, and retransmitting the coding packet; and respectively solving each lost original data packet by utilizing a Gaussian elimination method after each receiving node receives the coding packets with the preset amount. The method in the invention can be used for overcoming the defect that a traditional retransmission method is not suitable for point-to-multipoint broadcasting scene and also prevents limitation that performance is not stable and system expense is large in the retransmission method based on XOR (exclusive OR) coding, according to the wireless reliable broadcasting method based on the random linear network code, disclosed by the invention, linear network code and retransmission is carried out on the lost original data packet of each receiving node through lower coding algorithm complexity and system expense; and the receiving node can be used for solving the original data packet from the coding packet by utilizing a solution of a linear equation system, and the retransmission performance of wireless broadcast is modified, and the average retransmission times is reduced. The wireless reliable broadcasting method disclosed by the invention is stable, is not influenced by data package loss distribution and has good promotion application prospect.

The invention discloses a base station, user equipment and an uplink data transmission method. The method comprises the steps of carrying out blind detection on a preset grant-free resource pool; when uplink data retransmitted by the user equipment is detected, on the basis of a reference signal employed by the uplink data, determining a cause for the fact that previously transmitted uplink data is decoded unsuccessfully; selecting a corresponding independent decoding or combined decoding mode to decode the currently retransmitted uplink data according to the cause for the fact that previously transmitted uplink data is decoded unsuccessfully; and when the currently retransmitted uplink data is decoded unsuccessfully, on the basis of the cause for the fact that previously transmitted uplink data is decoded unsuccessfully, generating feedback information corresponding to current retransmission and sending the feedback information to the user equipment, thereby enabling the user equipment to select a corresponding grant-free multi-access resource from the grant-free resource pool to retransmit the uplink data under the instruction of the feedback information. According to the scheme, the transmission reliability of the uplink data is improved, the resources are saved, and the system efficiency is improved.

The invention discloses a combined hybrid automatic repeat request (HARQ) method, belonging to the field of wireless communication technology, aiming to effectively reduce the signal error rate, reduce retransmission number and increase throughout rate. The utility model is characterized that: a data transmission link is established between the sending end and the receiving end, the channel coding and the space-time coding structure are cascade connected; wherein, the number of the transmitting antenna at the sending end M is larger than one, M constellations or M kinds of bit sequence are stored at the sending end and the receiving end; one constellation is mapped or a bit sequence is rearranged and then mapped on a fixed constellation before each retransmission; then space-time coding is done according to a space-time coding structure; finally soft information combination and iterative decoding is done at the receiving end. The utility model has an advantage that the antenna diversity gain and the bit-symbol mapping diversity gain can effectively reduce the retransmission number and optimize system performance.

The disclosed adjustment method on channel quality indication for HSDPA system comprises: according to business type, selecting relative CQI adjustment algorithm to adjust reported CQI; to non-delay sensitive business, selecting CQI algorithm based on IBLER, while selecting CQI algorithm based on RBLER for delay sensitive business. This invention can adjust IBLER target value according to load condition.

The invention relates to an industrial wireless sensor network communication method based on relay nodes, belonging to the field of sensor network communication. A network management center distributes a preferred communication path resource according to the request of a source node and current network state information, selects a relay node and a relay path according to constraint conditions, and distributes the communication resources of the relay path. In the communication process, when the relay node receives the negative response from the node of the last hop, the probability that the transmission delay exceeds a threshold is reduced, the frequency of retransmission initiated by the source node is reduced, and the energy consumption for retransmitting data is reduced. Meanwhile, the relay node also dynamically changes the priority of data packets, avoids delaying transmission of the data packets again, and ensures that the data packets reach a destination node in delay requirements. By adopting collaboration among the relay node, the destination node and the network management center, the packet loss rate is reduced, the frequency of retransmission initiated by the source node is reduced, and the energy consumption for retransmitting data is reduced.

The invention discloses a method and device for controlling discontinuous reception in order to solve a problem that data transmission quality is decreased due to fact that a CDRX function is started. The method of the invention comprises steps of obtaining a parameter value characterizing quality of the current channel when discontinuous reception CDRX cycle is started under a state that a radio resource control protocol which is indicated by a network side RRC _CONNECTED is connected, and extending monitoring time for a physical downlink control channel-PDCCH channel in a CDRX cycle when the parameter value is greater than a first preset threshold value.

The invention discloses a method and system for adaptive adjustment in a modulation and coding scheme. When user equipment (UE) feeds back channel quality indicator (CQI) results to base stations, CQI results in a coordinative multiple point (CoMP) mode and CQI results in a non-CoMP mode are respectively fed back. The base stations judge whether the CoMP mode is carried out or not. The CQI results in the corresponding mode are selected according to judged results for carrying out modulation and coding scheme (MCS) mapping. A CQI feedback mode applicable to a CoMP coordinated beamforming scene is provided, when the UE feeds back the CQI results, differences of calculation interference between the base stations in the CoMP mode and the non-CoMP mode are fully considered, and therefore the base stations can select a proper MSC value.

The invention provides an LT code based spatial delay / disruption tolerant network (DTN) transmission method, which is characterized by comprising the steps that: A, a source file is divided into a plurality of data bundles, and the data bundle is divided so as to generate code segments; B, the data bundles carry out session transmission by taking a block as a session unit, a transmitting end transmits a code segment, a receiving end receives the code segment and carries out decoding relay on the code segment so as to generate a data segment, and the unsuccessfully recovered data segment is retransmitted; C, the above steps are repeated until the transmitting end confirms that the receiving end has recovered the data bundles successfully; and D, the next session transmission is carried out. The transmission method provided by the invention has small transmission delay and high handling capacity in a ground-fire communication scene set by the invention, and occupation of the node storage space is obviously reduced in the file transmission process.

This invention relates to a sub-carrier mapping method for circular shift at the transmission end including: corresponding input several digit data bits to a certain symbol in the modulated symbol set to output corresponding modulated symbols, circularly shifting the mapping relation between the modulated symbols last time and the sub-carrier to get the mapping relation of the symbol should be applied in transmission this time and sub-carriers to modulate the symbols onto each sub-carrier, which can realize that same bits in the transmission of a same HARQ process are transmitted on different sub-carries to get the frequency diversity gain and reduce the probability of failing transmission of HARQ because some bits are always transmitted on deep declined sub-carriers.

The invention discloses a capability acquisition method for a multimode terminal. The method comprises the following steps that a base station transmits a first terminal capability request to the multimode terminal according to the type of a current system to acquire the current system capability of the multimode terminal after receiving an attachment request sent by the multimode terminal; and the base station processes initial attachment initiated by the multimode terminal according to the system capability. According to the method, the multimode terminal can only report the capability of the multimode terminal for the current system in an initial attachment process, so that the number of bytes of a multimode terminal capability reporting message is reduced, the multimode terminal capability reporting message transmission failure rate and retransmission times in the initial attachment process are reduced, and the access time delay of the multimode terminal is further shortened.

The invention provides a method for improving end-to-end wireless transmission control protocol (TCP) linear network coding. Particularly, the method comprises the following steps of: (1) optimizing a network coding head frame design on a network coding layer, so that required parameters of coding and decoding are comprehensively considered, the length of a network coding head is shortened, and the complexity of the network coding head is reduced; (2) according to the condition of wireless network packet loss, designing reasonable sliding windows and coding windows, and optimizing so that the sizes of the sliding windows and the coding windows are equal; (3) determining piggyback information content to be network coding message sequence expected to be received next time; and (4) amending a message loss retransmission mechanism, and starting retransmission when the accumulated packet loss number of coding messages achieves the number of sliding windows. Through the operation, the complexity of network coding can be reduced, and the network coding efficiency and the TCP throughput of an end-to-end system are improved.

The invention provides a local cooperation method in wireless multicasting. During multicasting to a user, a mobile base station is divided into four stages: a first stage: the mobile base station broadcasts a certain number of data packets to the user; a second stage: the idle non-multicasting user codes the received data packets in the network and then forwards the data packets to the multicasting user, and the multicasting user repairs the data packets first time by utilizing the forwarded data packets; a third stage: the user in the multicasting group retransmits the data packets in a cooperation manner, and the error packet list of the multicasting user is split by a network coding method to obtain a local retransmission strategy, and the local retransmission of the data packets is performed according to the strategy; and a fourth state: when receiving the report, the mobile base station judges whether the data packets are retransmitted or not according to the feedback of the user. By adopting the method, the retransmission request of the multicasting user to the mobile base station is reduced, the retransmission relay is reduced, the retransmission times are lowered, the retransmission efficiency is improved, the retransmission load of the mobile base station is lightened, the honeycomb link resource is saved, and the utilization rate of the wireless resource is improved.

The invention discloses a transmission method and system of group speech data package, in order to increase the transmission efficiency of VoIP service. The sending end generates CRC verifying field based on one of IP packet header, UDP packet header, RTP packet header, CMR, ToC, and a substream of VoIP data package to be sent or any combination. The said verifying field is added to the said data package to be sent. The receiving end verifies only partial content of the data package, therefore the number of retransmission due to verity error is greatly reduced. For the voice coded by AMR, the length of CRC verifying field is contracted to 12 bits, under the precondition of satisfying the transmission demand, the required resource for transmitting the verifying field is reduced and the system capacity is furthermore increased.

The invention provides a data retransmission method based on network coding (NC), wherein the method has high NC efficiency. The method comprises the following steps: a statistics step, to be more specific, a source node sends data packets and then reception and statistics are carried out on all data packets' reception situations feedbacked by receiving nodes and a determination step is entered, wherein the data packets are original data packets or encoded data packets; the determination step, to be more specific, the source node determines whether it is necessary to retransmit the data packets; if so, a encoding step is entered; if not, retransmission is finished; the encoding step, to be more specific, the source node gives priority to NC of the data packet with the poorest reception situation according to an encoding rule so as to obtain a latest encoding data packet that is retransmitted this time as well as a sending step is entered; and the sending step, to be more specific, the source node broadcasts the data packet that is needed to be retransmitted this time to all the receiving nodes and the statistics step is returned to. According to the invention, a data packet with the poorest reception situation is used in preference to carry out NC, so that an encoding gain can be increased; and the larger the encoding gain is, the smaller the transmission frequency is.

The invention provides an improved method for a transmission control protocol based on network coding. The method comprises the steps of modifying a feedback system of the TCP protocol in a transmission layer and adding a network coding window, wherein the transmission layer maintains two windows which are a TCP window and a network coding window. The data are generated by an application layer and delivered to the TCP window from top to bottom; and the network coding window receives the data packet of the TCP window and caches the data packet to a cache region. When the network coding window receives a plurality of data packets, a designated number of coding data packets are obtained and are then delivered to a network layer and finally sent by a bottom layer. The retransmission time of the data packets can be obviously shortened, so that the network throughput is improved.

The invention provides a data retransmission method which comprises the following steps that: after completely transmitting N data packets, a source node acquires a packet-loss model matrix of the N data packets, wherein N is a natural number; the source node analyzes the acquired packet-loss model matrix so as to obtain a combination mode of data packets to be retransmitted; and the source node carries out combined encoding on the data packets to be retransmitted according to the combination mode of the data packets to be retransmitted to obtain encoding packets to be retransmitted, and sequentially retransmits the encoding packets. Accordingly, the invention also provides a data retransmission device. According to the invention, through analyzing the packet-loss model matrix, the data packets to be retransmitted can be effectively combined, thereby reducing the retransmission times, and improving the retransmission efficiency.

The invention relates to field of wireless network communication and discloses a video transmission method and device or a wireless network. According to the invention, if the network transmission state is monitored to be jammed, the video code stream is firstly subjected to first level frame rate reduction processing, if the network transmission state is still jammed in the preset time duration after the first level frame rate reduction processing, the video code stream is subjected to second level frame rate reduction processing, so that the video effect is smoother and unhindered. During frame rate reduction processing, the current content of a buffer area of the application layer is maintained, only the newly-generated video code stream is coded and compressed, and the monitoring video is more continuous. If the network transmission state is monitored to be not jammed in the preset time duration after the frame rate reduction processing, the low-speed frame rate increasing mechanism is adopted, and if the network environment becomes worse again, the quick frame rate reduction processing is carried out.

The invention relates to an adaptive automatic repeat request method, belonging to the wireless communication technology, which aims to combine channel coding with space-time coding, adjust the transmission modes adaptively, reduce repeat times effectively and improve the spectrum efficiency of the system. The invention is characterized in that a sending end is connected with a receiving end via a transmission link; the sending end has a plurality of transmission modes; a corresponding table of the transmission modes is formed; each transmission mode has a certain range of transmission times; a mode transmission graph of the transmission modes is formed. The invention has the advantages of adjusting channel coding mode, modulation mode and space-time coding mode via adjusting the transmission modes adaptively, reducing repeat times effectively, improving the channel utilization and the spectrum efficiency, reducing the implementation complexity and improving the performance of the system via ACK or NACK feedback choosing transmission modes flexibly when the slow channel is fading.

The invention discloses a network coding-based wireless cooperative broadcasting / multicasting method. In the method, a network coding data packet for retransmission is formed by combining and constructing data packets lost by a user in a network coding mode, and a cooperative user assists a user who fails to correctly receive all data packets at a first phase in receiving all data packets. The method is implemented by the following steps of: transmitting data packets by using a data source; selecting the cooperative user and specifying a request and performing network coding configuration; and transmitting network coding data packets in a cooperative way. A retransmission network coding data packet is constructed through network coding and user cooperation, so that retransmission times can be greatly reduced and system efficiency is improved.

The invention relates to a Bluetooth communication method, a Bluetooth communication system, a Bluetooth receiving method and a Bluetooth receiving device. The Bluetooth communication method comprisesthe steps of: sending generated Bluetooth data through multiple Bluetooth sending branches in different frequency-domain channels; receiving the Bluetooth data in multiple Bluetooth receiving branches through different frequency-domain channels, wherein the Bluetooth data includes cyclic redundancy check information and load data; and, determining a current working mode, determining whether the load data in the multiple Bluetooth receiving branches is retransmitted or not in the current working mode according to the cyclic redundancy check information in the multiple Bluetooth receiving branches, and screening out output data in non-retransmission load data. According to the Bluetooth communication method, the Bluetooth communication system, the Bluetooth receiving method and the Bluetooth receiving device disclosed by the invention, the Bluetooth data is received / sent through the multiple different frequency-domain channels; furthermore, a check retransmission mechanism in differentworking modes is provided; therefore, the Bluetooth system retransmission time is effectively reduced, so that the communication efficiency is increased; and thus, high-quality and reliable Bluetoothinformation transmission is completed.

An improved packet transmission is disclosed. According to the invention, a transmitter includes a number of entities working according to a number of protocols, these protocols including a MAC (Media Access Control) layer protocol and a number of protocols of layers higher than the MAC layer. This transmitter is to transmit at least one packet, wherein at least a part of the packet is encoded by an encoder supporting UEP (Unequal Error Protection). A MAC layer entity of the transmitter receives, from at least one of the higher layer entities, the at least one packet to be transmitted and at least one packet parameter. The transmitter then chooses, based on said at least one packet parameter, a partial error protection to be applied to the at least one packet. Further, the transmitter transmits the at least one packet to a receiver in said telecommunication system, applying the chosen partial error protection to the at least one packet, and also indicates the applied partial error protection to said receiver in a way agreed between said transmitter and said receiver.

The invention discloses a method and apparatus for reducing data packet retransmission times in reliable multicast transmission. The method comprises the following steps: after packet loss of received reliable multicast data is detected, if retransmission request messages sent by other multicast receiving devices are not received within a delay transmission time, sending the retransmission request messages containing sequence numbers of all lost data packets through a multicast data packet, and if the retransmission request messages sent by the other multicast receiving devices are received within the delay transmission time, sending the retransmission request messages through the multicast data packet, wherein the sequence numbers of the lost data packets in the retransmission request messages do not contain the sequence numbers in the retransmission request messages sent by the other multicast receiving devices. The corresponding apparatus comprises a packet loss detection module and a retransmission request module. By adopting the method and apparatus disclosed by the invention, the data packet retransmission times in the reliable multicast transmission are greatly reduced, and the burden of a multicast source and a multicast transmission device is relieved.

The present invention relates to methods and arrangements that enable continuous adaptive control of the number of autonomous HARQ retransmissions. This is achieved by a solution, where the UE and the radio base station are using a number of autonomous HARQ retransmissions that can be adjusted based on observations in the UE and / or the radio base station. What is observed is the amount of HARQ retransmissions needed for the radio base station to correctly decode the latest received data packet(s).

The technical scheme of the invention is used in a one-to-many broadcast communications system, which further optimizes the performance of the system by combining two up-to-the-minute communications technologies, namely network coding (NC) and stacked coding (SC), and designing to simultaneously utilize the gain in the aspects of system throughput, time delay and the like. The technical scheme is easy to achieve, and the application method is relatively flexible. The information for transmission is reasonably designed during first transmission and retransmission, and the NC technology and the SC technology are effectively combined. Firstly, information with different priorities is reused on different constellations of the SC, thereby increasing the throughput of the system; and then during retransmission, according to the wrong patterns fed back from a receiving end recorded by a sending end, the retransmitted information is designed by using network coding, and the coded information is transmitted by using stacked coding, thereby reducing the retransmission times and the retransmission time delay.