320 results about "Fountain code" patented technology

In a first aspect, an aggregated packet (A-MPDU) includes packets (MPDUs) and EC-Blocks (Error Correction Blocks) containing error correction coding information. A transmitter uses a Fountain coding scheme (for example, Raptor or RaptorQ) to generate the error correction coding information from the MPDUs. If a receiver detects an error in a received MPDU, then the receiver uses the error correction coding information from the EC-Blocks to correct the error. In a second novel aspect, a determination is made as to whether a change in error rate is more likely due to collisions or to a low SNR. If the determination is that the change is due to collisions then the MCS index is adjusted to restore a target error rate, whereas if the determination is that the change is due to a low SNR then the number of EC-Blocks per A-MPDU is adjusted to restore the target error rate.

The invention discloses a coding/decoding method for fountain codes. The coding method comprises the following steps: dividing raw data blocks into different information layers in the descending order of priority; precoding each information layer at the same code rate, connecting the obtained coded layers in a cascade mode, and sending to a priority LT coder to carry out LT coding; and in the coding process, dynamically adjusting the size of the input symbol set of each code symbol according to the adjustment parameter, and controlling the unequal protection degrees of data in different priorities. The decoding method comprises the following steps: a priority LT decoder decodes the received coded data packet to obtain output data with unequal error protection functions; a data diverter divides the output data into different coded layers according to the number of layer; and each coded layer is respectively sent into the corresponding precoding decoder to decode the precoding, thereby restoring each information layer. The invention also discloses a coding/decoding device for fountain codes. By using the invention, video can be efficiently and reliably transmitted in a layered multicasting environment.

A method of optical underwater communications comprises applying a Fountain code to a plurality of data blocks. A sequence of optical data packets is transmitted through an underwater communications channel. Each optical data packet comprises one of the plurality of data blocks preceded by a preamble. The sequence of optical data packets transmitted through the underwater communication channel is received to generate a sequence of received data packets. The sequence of received data packets is sampled with the sampling clock to recover the plurality of data blocks.

The invention provides a fountain code compiling method based on deep space communication environment. The method comprises the following steps of: A) dividing information bits to be transmitted to form a plurality of original information groups; B) performing fountain coding on the original information groups to form code groups; C, performing concatenated error correction coding on the code groups, and transmitting the code groups to a receiver by using a deep space channel; D, performing concatenated error correction decoding to recover the code groups; and E, after enough code groups are obtained, performing fountain decoding to recover all the original information groups. In the method, partial randomness in a conventional fountain coding process is limited for the characteristics of the deep space channel so as to effectively reduce coding redundancy overhead and directively solve the problems of limitations to the transmission power and memory space of fountain codes in a deep space environment on the premise of not changing original degree distribution.

System and method embodiments are provided for enabling flexible and reliable UE-to-UE based relay. The embodiments include using fountain codes for combining signals at a suitable network layer higher than a media access control (MAC) sub-layer and using a MAC sub-layer hybrid automatic repeat request (HARQ) transmission scheme. When a relay UE in a UE group for joint reception receives, from a network access point, a data packet intended for a destination UE in the UE group and including fountain code at the higher network layer, the relay UE sends the data packet to the destination UE and returns a HARQ ACK message at the MAC sub-layer to the access point. The destination UE then receives and decodes the data packet. Subsequently, upon receiving the entire data, the destination UE sends an ACK message at the higher network layer to the access point.

The invention relates to the information technology field of radio electronics and telecommunication technology, and relates to an aggregate of wireless enhancement technology of high-speed data transmission in the wireless communication field, in particular to an all-in-one feedback retransmission method based on fountain code mainly applied to wireless channel data transmission high-speed data service in a general mobile communication system. The method utilizes the ratioless channel coding principle of the fountain code, improves the existing mixed bit error feedback retransmission HARQ method and data coding mode in a wireless link, and mainly solves the relevant technical problems of how to utilize unique fountain code series to carry out the algorithm flow of coding and decoding foreach data block. The method has the beneficial effects that the feedback retransmission method and relevant fountain code design scheme can lead the data throughput of the wireless link to be improvedby 110% compared with the prior art, and the method has higher efficiency when the data blocks segmented in each group is more or the initial transmission groups sharing the same retransmission groupare more.

The invention discloses a data transmission method and a system. The data transmission method comprises the following steps: a first user sends a data package encoded by using fountain codes to a control station; a second user sends a data package encoded by using fountain codes to the control station; the control station conducts network encoding on the data packages sent by the first user and the second user; and the control station encodes the data packages after network encoding by using the fountain codes and then sends the data packages to the first user and the second user. Through the scheme, the problem of error propagation can be effectively overcome, the accuracy of receiving and sending data can be improved, and the decoding cost in the transmission process of data and encoding and decoding complexity can be reduced.

The invention belongs to the communication technology field, relating to a channel coding transmission method based on an unequal mistake protection fountain code. The method comprises the following steps: classifying a signal source according to importance; carrying out virtual expansion on each r layer data according to expansion factor; putting obtained virtual extension layer data into each window; carrying out progressive analysis on the window data with and/or tree algorithm; carrying out LT coding and index replacement according to robustness solitary wave degree; obtaining coding word; carrying out transmission; carrying out decoding. According to the invention, protection of important data is reinforced, simultaneously protection of less important data is not decreased to guarantee to reliable transmission of data.

The invention discloses a self-adapting fountain code multicast transmission system based on modulation, which comprises a base station and a plurality of user sides. The base station comprises a base station data memory, a fountain coder, a user classification processor, a superposition coder, a modulator, a base station duplex transceiver and a feedback information processing module; and each user side comprises a terminal duplex transceiver, a serial interference cancellation decoder, a terminal data memory, a fountain decoder and a feedback generator. In a correcting and deleting channel, a mode of digital fountain codes is adopted for transmission so as to reduce the feedback in a multicast environment and improve the throughput rate of the system. According to a multi-user channel state, modulation modes are self-adaptively switched and selected. When the performance difference among the users is small, a common modulation mode is adopted; and when the performance difference among the users is large, superposition coding for different user information is carried out through power distribution so that the system still can keep good transmission performance. The combination of the digital fountain code and the superposition coding exerts the advantages of the digital fountain code and improves the performances.

The invention discloses a fountain code-based multi-path parallel transmission method and apparatus. The method includes the following steps that: original data packets to be sent are cached respectively according to the address of a receiving end; whether the number of the original data packets in caching reaches a preset number or whether the waiting time of the original data packets in caching exceeds a preset value is judged; if the number of the original data packets in caching reaches the preset number or the waiting time of the original data packets in caching exceeds the preset value, fountain encoding is carried out on the original data packets in caching, so that encoded data packets can be obtained; the overall conditions of a plurality of tunnels for transmitting the encoded data packets are obtained, and the overall conditions of the plurality of tunnels are divided into a performance good condition and a performance poor condition, and corresponding transmission modes are selected according to the overall conditions, corresponding tunnels are selected for the encoded data packets according to the scale values of the encoded data packets under the corresponding transmission modes, and the transmission modes of the encoded data packets are adjusted correspondingly in different stages of the transmission process of the encoded data packets; and a feedback module is set at the receiving end, a sending end is made to judge whether the transmission process is completed, and therefore, multi-path parallel transmission of the original data packets can be realized, and link utilization rate and transmission reliability can be improved.

The invention relates to a multi-system fountain coding and decoding method based on a finite field. Firstly, a fountain code is coded to obtain a fountain coding sequence: a coding-level distribution function Mu(d) is given and a nonnegative integer di is randomly generated according to the distribution function Mu(d), and di is used as the coding level of a coded symbol vi; di different symbols are randomly selected from K information source symbols; di nonzero values are generated in a finite field GF(q) randomly and evenly and used as coding coefficients of the coded symbol vi; weighted sum is obtained for the di different symbols according to the coded coefficients to obtain the value of the coded symbol vi so as to further obtain the fountain coding sequences. Coding sequences with the length of N (N is more than or equal to K) are selected from the fountain coding sequences and designated to be that w equals to (w1, w2, until wN). Decoding is carried out to the coding sequences by pivot selection and pivot in-situ Gauss elimination to obtain a final decoding output sequence. The method greatly improves the fountain coding efficiency, reduces the decoding complexity of the fountain code and is applicable to the fountain codes with various lengths of the information source.

The invention discloses transmitting and receiving methods and systems of an HARQ (hybrid automatic repeat request) technology adopting fountain codes... A transmitting module comprises a transmitted data fountain encoder, a first CRC (cyclical redundancy check) encoder, a first modulator, a feedback retransmitted data fountain encoder and a second CRC encoder, wherein the transmitted data fountain encoder is used for receiving to-be-transmitted data streams, and carrying out fountain encoding on the to-be-transmitted data streams; the first CRC encoder is connected with the output of the transmitted data fountain encoder, and used for carrying out CRC encoding; the first modulator is connected with the output of the first CRC encoder, and used for carrying out signal modulation, and transmitting output signals to a channel; the feedback retransmitted data fountain encoder is controlled by a retransmission request unit, and used for receiving the to-be-transmitted data streams, and carrying out fountain encoding on the to-be-transmitted data streams; and the second CRC encoder is connected with the output of the second CRC encoder, and used for carrying out signal modulation, and transmitting output signals to the channel. The invention also discloses corresponding receiving modules, systems and methods. The methods and systems disclosed by the invention aim to improve the transmission efficiency and the transmission reliability.

The invention provides a fountain code decoding method suitable for a radio broadcasting system. The decoding method includes: step one, calcifying signals after passing a channel decoder into a group with residual errors and a group without residual errors at the receiving end; step two, for the group without the residual errors, setting a log likelihood ratio (LLR) value with a corresponding bit of zero as a large positive number (such as the positive infinity) and an LLR value with a corresponding bit of one as a small negative number (such as the negative infinity), and collecting LLR values of the group with the residual errors to participate in the decoding process of the function code; and step three, trying to decode all source symbol sets through hard iteration of a coded symbol with certain messages and updating a bipartite graph of the fountain code in a bit domain and an LLR domain during the iteration. The method has the advantages of high spectrum efficiency due to retention of the group with the residual errors and low decoding complexity.

A method and apparatus are described including receiving content, applying fountain codes to symbols of the content to generate fountain encoded symbols at one of a transport layer and an application layer and transmitting the generated fountain encode symbols via a mobile network that uses a multi-link delivery system. Also described are a method and apparatus including receiving data packets of fountain encoded symbols via a mobile network that uses a multi-link delivery system, decoding the received data packets of fountain encoded symbols to content data, attempting to recover any corrupted content data and determining if the content data was recovered.

The invention relates to a device-to-device (D2D) multimedia broadcast multicast service (MBMS) method on the basis of beam forming and fountain codes, in particular to a MBMS scheme on the basis of a D2D system, in which a fountain coding technology and a beam forming technology are introduced, and belongs to the technical field of communication. Every when a D2D transmitting terminal receives an ACK (Acknowledgement Character) signal fed back by one D2D receiving set, according to a principle in proportion to the number of users in a receiving set of which the power is not limited, the maximum transmittable power of the receiving set of which the power is not limited in the current D2D communication receiving sets is redistributed, so that the total transmitting power of the D2D transmitting terminal is always kept into the maximum transmitting power. According to the method disclosed by the invention, the unnecessary energy waste and the interference to users in an adjacent origin cell, which are caused by the omnibearing radiation of a transmitting antenna, can be reduced and the throughput of the D2D system is improved.

Information codes are arranged in pieces comprised of chunks of bytes over a network, such as a Peer-to-Peer overlay network, including a set of peer terminals. A first peer identifies missing chunks in the received pieces and requests such missing chunks from other peers. The chunks are subjected to a fountain code encoding wherein the chunks in a piece are X-ORed. The first peer is therefore capable of reconstructing a received piece encoded with fountain codes from a combination of linearly independent chunks corresponding to the piece. The chunks are transmitted over the network with a connection-less protocol, without retransmission of lost packets, preferably with a UDP protocol.

The invention discloses a deep space multi-file transmission method based on fountain codes. According to the method, the codeless characteristic of the fountain codes is fully utilized, and a forward channel is fully utilized to reduce the data size on a backward channel, so that the link utilization rate is increased, and time delay is shortened. According to latest packet loss rate information, required coding redundancy is calculated, the success rate of primary transmission is increased, and the redundancy is effectively controlled; with respect to the receiving party, a united decoding algorithm is adopted, coded information is fully utilized, the calculation complexity is lowered, and the success rate of decoding is increased; in the retransmission process, different protection strategies are adopted according to different packet loss conditions to reduce retransmission frequency; a multi-file united transmission strategy is adopted, feedback information of the receiving party is not waited for, files to be transmitted are processed directly, link resources are fully utilized, and time delay is shortened; on the basis of a CFDP, a coding packet is sent as content of a data field, so that good compatibility and practicability are guaranteed. By means of the deep space multi-file transmission method based on the fountain codes, the problems of huge transmission delay, link time varying and channel asymmetry are solved in a targeted mode, the redundancy is effectively controlled, the transmission frequency is reduced, and the goal of efficient and reliable transmission of deep space files is basically achieved.

The invention relates to an opportunistic routing protocol data distributing method based on fountain code and network coding. The method includes the specific steps of numbering all the network nodes and establishing routing information under the TinyOS system; segmenting and numbering the data, calculating the receive threshold of each node; with regard to source nodes, carrying out the precoding to the data via fountain codes, and maintaining a send window which controls the quantity of the data packet in the network; with regard to intermediate nodes, carrying out the network coding to the data packet of the same segment, and sending the coded data by the opportunistic routing method; with regard to information sink codes, carrying out the network decoding to the data, and then carrying out the fountain code decoding to the data which go through the network decoding. The invention realizes the combination of the network coding and the opportunistic routing, increases the contentsof information in single transmission, but decreases the transmission and retransmission frequencies of the data packet, thus having the advantages of reliable data transmission, improved network efficiency, and reduced energy consumption of sensor nodes.

The invention discloses a method for guaranteeing secure transmission of wireless data based on fountain codes. The method comprises the following steps that each time slot sending end adopts a fountain code method to complete a check package encoding process; after the check package generated at the sending end is subjected to CRC (Cyclic Redundancy Check) coding of a data link layer and channel coding of a physical layer, the check package is sent to a legal user, and a tapping user taps current time slot transmission check package information; when packet loss does not occur in the channel, a legal receiving end completes a decoded operation of the received check package, and updates a set of serial numbers of decoded information packets and feeds the set back to the sending end after correct decoding, otherwise the set of the serial numbers of the decoded information packets is not updated; and the legal receiving end judges whether the number of the successfully decoded information packets is equal to the number of source information packets and decides whether to inform the sending end to stop sending the check package according to the information. According to the method, real-time adjustment of an encoding scheme for the sending end is carried out according to the decoding speed of the legal user, so that the intercept probability for the tapping user in a wireless data transmission process is remarkably reduced and the transmission efficiency of the sending end is improved.

The invention discloses a method for accelerating a TCP (Transmission Control Protocol) under a severe channel. The method is applied to a severe wireless channel, has the advantages of solving the problem of low throughput of the conventional TCP and other TCP improved algorithms in the practical severe wireless application environment, effectively utilizing the channel and greatly increasing the utilization ratio of wireless frequency spectrums, and is suitable for rapid one-to-one, one-to-many even many-to-many communication environments in a plurality of severe application scenes such as armies, emergencies, emergency rescues, disaster reliefs and the like. The method for accelerating the TCP comprises the following steps of: 702, judging whether delay is larger than a first preset value; 703, if the delay judging result is positive, performing fountain code acceleration; 704, if the delay judging result is negative, judging whether the packet loss ratio is larger than a second preset value; 705, if the packet loss ratio judging result is positive, adopting selective retransmission; and 706, if the packet loss ratio judging result is negative, adopting the conventional TCP scheme.

The invention relates to an encoding method based on low-density parity check codes- cascaded codes synthesized by fountain codes in a deep space communication system. The method includes step one: information waiting for transmission is divided into a plurality of first-level information units; step two: the first-level information units are encoded by the spring codes to produce second-level information units; step three: the second-level information units are encoded by the low-density parity check codes to produce third-level information units; step four: the third-level information units are transmitted by deep space communication channels; step five: the received third-level information units are decoded by the low-density parity check codes and the successfully-decoded information units are formed into fourth-level information units; and step six: the fourth-level information units are decoded by the spring codes and decrypted. The invention needs no feedback re-transmission and can retrieve the original information by the receiving of subsequent information units and achieve a constant error rate demanded by the communication system under different channel conditions.

The invention relates to an encoding and decoding technology, and especially relates to a two-dimensional distribution design method for a distributed fountain code. The method comprises the following steps: step A, establishing a distributed network system model; step B, designing a two-dimensional distribution network coding relaying protocol, wherein the whole coding process is divided into two parts, one part is fountain coding at an information source node in the previous two stages of the conversation process, and the other part is network coding based on two-dimensional distribution in the third stage of the conversation process; step C, analyzing the decoding performance; and step D, optimizing a degree distribution function. The two-dimensional distribution design method for the distributed fountain code provided by the invention can be applicable to multi-source data download and storage in a distributed system, and can also be used as a distributed cooperative transmission scheme in cooperative communication; meanwhile, under the condition of facing to topological structures like a time varying channel, an asymmetrical network structure in a spatial information network, the distributed fountain code scheme can greatly improve the effectiveness of network system transmission and reduce the energy consumption of the system by means of network coding adaptive scheduling.

The invention relates to a file transmission method in deep space communication and belongs to the technical field of deep space communication. According to the method, the predetermined coding redundancy is used for carrying out fountain coding on file data grouping, then, the sending is carried out through a link, a mode that a sending end actively stops is adopted, the one-step successful transmission probability of files is improved, the file transmission efficiency is improved, the bandwidth waste in large delay deep space communication environment caused by the passive stop of the sending end is avoided, and the link utilization rate is improved; and meanwhile, a reliable file transmission method in CFDP (CCSDS (consultative committee for space data system) file delivery protocol) is combined, the contents of a file data PDU (protocol data unit) and the contents of an NAK (negative acknowledge) PDU are defined, the reliable transmission of deep space files on the basis of the fountain coding is realized, and good protocol compatibility and practicability are realized.

A fountain code-based cooperative multicast method comprises: 1) transmitting forwards, by a base station, a code symbol informed by a packet encoded by a fountain code, after receiving a feedback that all users correctly decode by the base station, stopping transmitting a data; 2) after completing receiving the data early by a user with good channel conditions, monitoring a “help” signal of other users, when receiving the “help” signal, the user with good channel conditions participates in a cooperation, when receiving the feedback of a cooperative user that has correctly received the data, stopping the cooperation by the user with good channel conditions; and 3) monitoring a feedback signal of remaining users that correctly receive the data by a user that does not complete receiving the data, and deciding whether to transmit a “help” signal, according to a signal intensity of the—feedback signal.

The invention discloses a network coding method based on fountain codes, belonging to the technical field of coding. The invention aims at combining the network codes with the fountain codes so as to realize reliable and effective transmission in the wireless network. The network coding method based on fountain codes comprises the following steps of: carrying out first stage fountain coding to information source, transmitting the first stage fountain coding symbols to the middle nodes in a way of fountain coding, carrying out fountain decoding to the middle nodes, carrying out fountain broadcasting to the middle nodes, collecting fountain coding symbols and carrying out fountain decoding by information sink nodes, and then obtaining the network coding method based on fountain codes . The method combines the advantages of the network codes with the advantages of the fountain codes and can effectively improve the data throughput and reliability of the network.