76results about How to "Reduce frame error rate" patented technology

The invention discloses a density evolution based polarization code constructing method and polarization code coding and decoding system. According to the invention, the code length N and the information bit length K of an information code to be processed are obtained, an expectation value set of a log-likelihood ratio probability density function of N bit channels, K bit channels are selected as the information bit channels according to the expectation value set and information bit information index vector quantity is generated; an information bit sequence and a fixed bit sequence are mixed and the mixed bit vector quantity is multiplied by a polarization code for generating a matrix so as to output an encoding sequence; the encoding sequence is modulated and input into a transmission channel and the sequence output by the transmission channel is subjected to decoding operation by adopting a polarization code decoding algorithm, bit error probability and frame error rate of the decoded code are calculated and a design signal to noise ratio is changed, the above operation is repeated until the bit error probability and frame error rate become the minimum. The method and system provided by the invention are suitable for general binary system memoryless channels, the bit error probability and frame error rate are low, the calculation complexity is low and the communication performance of a communication system is improved.

A signal diversity method of an OFDM system comprises the following steps: carrying out data decoding, modulation and rotation-modulation by a transmitting end, and storing the symbols of the processed data blocks; subjecting the symbols of the data blocks of a plurality of users in a memory to grouping and time-frequency interleaving, OFDM time-frequency resource allocation and Q-path interleaving according to the set number of the users, respectively subjecting the symbols of each data block to IFFT operation and CP addition after zero padding according to the OFDM modulation length, then transmitting the data; and subjecting the symbols of the data blocks to de-CP and FFT operations after a receiving end receives the data, carrying out phase compensation and zero removal, and sequentially subjecting the symbols of the obtained data blocks to Q-path de-interleaving, rotation demodulation, time-frequency de-interleaving and coding to obtain the desired data information. By adopting OFDM technique and rotation modulation technique and by selecting an optimal rotation angle, the method can acquire signal diversity gain and maximal performance improvement, thereby improving the system performance.

The invention relates to a method for rotating modulation signals based on an MIMO-OFDM system, the method mutually combines three technologies of MIMO, OFDM and rotation modulation and comprises the steps of firstly introducing a signal modulation subset into rotation and component interweaving which are used for modulating a constellation diagram, dispersing sending data onto different components by rotation modulation and component interweaving, leading an I path component and a Q path component generated by modulation symbols after sending during the transmission process to carry out independent transmission on the respective fading channel, eliminating the correlation between I path and Q path fading factors of sending signals, increasing the advantages of a signal space subset, obtaining gains of the modulation subset, selecting an optimal rotation angle, obtaining the greatest upgrade of transmission performance and simultaneously introducing a space subset of multiple antennas, a frequency subset of an OFDM system and a time-frequency interweaving subset, thereby leading the system to achieve very high transmission efficiency, improving the utilization rate of frequency spectrum, realizing the transmission with high reliability through the subsets, reducing the bit error rate and the frame error rate, being close to the channel capacities of the fading channels and meeting the requirements of development of the next generation of a wireless transmission network.

The invention relates to a method for the modulation diversity of joint codes of an OFDM system. The method leads signal modulation diversity by modulating the rotation of a constellation picture and interlacing components, dispersedly distributes data prepared to be transmitted to different components by rotation modulation and component interlacement so that the data of the different componentsare respectively decayed on a channel to increase superiorities of signal space diversity, then selects an optical rotation angle to maximally enhance transmission property and also leads OFDM frequency diversity and time-frequency interlacement diversity, thereby more effectively enhancing the property of the system. The invention is improved from a previous invention patent application, i.e. a method for the signal diversity of the OFDM system (application number: 2008102264831) and expands an original diversity technique enhancing and improving the transmission property by two-dimensional rotation modulation to a multi-dimensional rotation modulation technique, thereby well utilizing the modulation diversity to be combined with time diversity and frequency domain diversity to enhance the property of the system.

The invention provides a combined pre-coding and power allocation method of the multi-cast network based on the network coding in the wireless communication field. In the invention, a multi-cast network formed by two-source, two-place and arbitrary relaying cluster is adopted. Two sinks need to obtain the information of each source and can not cross-transmit the signal due to the limit of the sending power, so the relaying node is responsible for forwarding information of each source. Through introducing simulation network coding into the relaying, namely, the received aliasing signal of the two sources is broadcast out after linear amplification, thus minimizing the transmission time to the maximum extent. The invention improves the network error frame performance and enhances the overall through put of the network by introducing the combined pre-coding and power allocation.

A method and apparatus for controlling iterative decoding in a turbo decoder are provided, in which a maximum number of iterations is determined for current data to be decoded based on at least one of current HARQ information necessary for a HARQ operation of the current data, previous HARQ information about previous data, and early stop information indicating whether iterative decoding of the previous data was early stopped. A turbo decoder iteratively decodes the current data within the maximum number of iterations.

The embodiment of the invention provides a reception / transmission combining method. The method comprises the following steps: receiving and caching data symbols that are transmitted at least twice by a transmitting terminal relative to a group of data, wherein the data symbols are acquired after modulating the data by the transmitting terminal; and combining the received data symbols and subjecting to channel equalization, and then obtaining the combined received data by means of demodulation and decoding. The embodiment of the invention also provides a reception / transmission combining methodsystem and a reception / transmission combining device. The reception / transmission combining method demodulates and decodes the received data symbols that are transmitted at least twice after channel equalization, achieves the effect of symbol-level reception / transmission combination of the data, effectively improves the system performance, reduces the frame error rate and the bit error rate, and increases the channel capacity and the spectrum utilization rate of the system.

The invention relates to the technical field of mobile communication, in particular to a receiving and combining technology. The embodiment of the invention provides a receiving and combining method, a system and a device thereof, which improve the system performance effectively. The receiving and combining method based on data retransmission comprises the following steps: the data symbols which carry out at least twice emitting to one group of data are received and buffered; after interference cancellation and symbol combination are carried out to the data symbols, the data symbols are demodulated and decoded, thus obtaining the combined receiving data. The receiving and combining system based on data retransmission comprises an emitting device and a receiving device. The embodiment of the invention provides an emitting device and a receiving device, and the embodiment of the invention also provides a receiving and combining method based on transmit diversity and a system thereof.

The invention relates to the technical field of mobile communication, in particular to data sending technology for a multi-input multi-output (MIMO) system and corresponding data receiving technology. The embodiment of the invention provides a data sending method, a corresponding data receiving method, a corresponding data receiving device and corresponding data receiving equipment for the MIMO system, and is used for increasing the signal-to-interference-plus-noise ratio of received signals of the MIMO system and improving the performance of the system. The data sending method for the MIMO system comprises the following steps: at least two groups of data of the same user are subjected to channel coding and interweaving respectively, and interweaving patterns adopted when the data are interwoven are not same; two data sequences obtained after the interweaving are modulated respectively and then are sent, and interweaving pattern indication information adopted when the data are interwoven is sent.

The invention relates to a method for a rotation modulation signal of an MIMO system, which comprises the following steps: eliminating the relativity of the fading coefficients of I-path and Q-path channels sending the modulation signals by adopting rotation modulation and Q-path orthogonal component interweaving, and increasing the modulation diversity number to acquire modulation diversity gain; then leading in the time diversity and space diversity of the MIMO system, thereby improving the availability of frequency spectra even though the system achieves high transmission efficiency in the transmission process of a fading channel, realizing high transmission reliability through a plurality of diversities, decreasing an error rate and an error frame rate, approaching to an ideal channel capacity under the fading channel, and satisfying the development requirement of a wireless transmission net. Moreover, the method has simple and practical operation steps, low computational complexity and marked efficiency, can be used for a multiple code modulation technical scheme, is especially suitable for communication systems with high encoding rate code words, multiple antennae, high spectrum effectiveness and the like, and is superior to a BICM-MIMO system on integrated transmission performance.

The invention provides a device and method for verification and error correction by cyclic redundancy. According to an embodiment of the invention, a CRC error correction table is arranged. The information in the CRC error correction table indicates a correctable error pattern and a corresponding relation related to a syndrome; executing cyclic redundancy verification and error correction for received code words, if the syndrome is not zero, searching in the CRC error correction table. If an item in the table or corresponding to the syndrome is found, received code words are corrected according to corresponding correctable error pattern. According to an embodiment, the correctable error pattern is a double bit error in a continuous two symbols scale. The invention can reduces an error frame ratio, in particular applied to a personal portable phone system.

A turbo encoded H-ARQ system and an error detection method are disclosed, and more particularly, a turbo encoded H-ARQ system and an error detection method that lower an undetected error probability and frame error rates by increasing the degree of an equivalent CRC generator polynomial by using a modified trellis termination. It has been made possible to obtain an equivalent CRC generator polynomial having higher degree than the related art CRC generator polynomial by employing a modified trellis termination. This achieved a lower undetected error probability than the related art undetected error probability by using an equivalent CRC generator polynomial having higher degree. This also achieved lower frame error rates, when the same number of overhead bits are used, due to the lower undetected error probability.

The embodiment of the invention discloses a maximum likelihood receiver data processing method and device and relates to the technical field of communication. The method and device can solve the problems that parameters needed by an ML receiver cannot be accurately estimated, and the interference eliminating capacity of the ML receiver is reduced. The method includes the steps that the ML receiver estimates channels of a serving cell and an interference cell through signals in the position of a received reference signal, and a channel estimation matrix is obtained; first measurement of the received signal and first measurement of the channel estimation matrix are computed, and the survival path of the serving cell is determined according to the first measurement; second measurement of the received signal and second measurement of the channel estimation matrix are computed according to the determined survival path of the serving cell and all values of unknown parameters, and the survival path of the interference cell is determined according to the second measurement; a final survival path is determined according to the survival path of the interference cell; an LLR is computed according to the final survival path. The maximum likelihood receiver data processing method and device are applicable to ML receivers.

The invention discloses a frequency hopping anti-interference method based on error correction and erasure correction RS-Turbo concatenated codes. The method mainly solves the problem that an existing frequency hopping communication system cannot conduct communication normally under the interference of carrier frequency deviation and partial bands. The method includes the steps that (1) RS coding is conducted on a frame of data; (2) each code element of an RS code is distributed onto a corresponding hop; (3) Trubo coding is conducted on each hop of data; (4) a frequency hopping framing format is set, and QPSK modulation is conducted; (5) carrier frequency deviation, phase deviation and Gaussian white noise are added in modulating signals, and complex base-band signals are obtained; (6) carrier synchronization is conducted on the complex base-band signals; (7) Turbo decoding is conducted on synchronous signals, and a deletion digit of the RS code is provided; (8) error correction and erasure correction decoding is conducted according to the deletion digit of the RS code. The method has the advantages of being good in error bit ratio and high in anti-interference performance and can be applied to mobile communications, satellite communications, deep space communications and remote metering.

In a mobile communication system 100 of the third generation CDMA type. A base station control apparatus 1 controls a transmission power of an opponent communication apparatus by means of measuring a FER within a predetermined segment, averaging plural pieces of quality information per frame, producing a translation table 40c by means of associating the FER acquired by the measurement and average frame quality information acquired by the averaging, estimating an estimated FER corresponding to the quality information per frame from the translation table 40c, and controlling a target receive power threshold based on the estimated FER and a target FER stored in advance, thereby quickly carrying out the transmission power control, improving the data quality of a lower layer, maintaining the data quality as constant, and increasing the throughput.

The invention provides a modulation codebook design method for a sparse code multiple access system. The method comprises the following steps: firstly, calculating the number of resource multiplexingusers on each carrier according to current system parameters, comprising the number of carrier resources, the number of users and the number of carrier resources occupied by each user, and designing amapping relationship between the users and the carrier resources; then, designing a modulation constellation graph of each user according to the number of the resource multiplexing users on each carrier and the number of constellation points of each user on each dimension; and finally, obtaining the modulation constellation graphs of the resource multiplexing users on all carriers according to the mapping relationship between the users and the carrier resources, obtaining the mapping relationship between bit sequences and modulation constellation point symbols on different constellation dimensions according to symbol interleaving transformation, and obtaining a final modulation codebook constellation graph. The high-dimensional codebook design method provided by the invention has the advantages of being simple in operation steps, being advantageous for implementation, and being able to bring better transmission performance to the system.

The invention discloses a receiving method of a ship automatic identification system, a receiver and a communication satellite. The receiving method comprises the following steps: receiving an AIS radio frequency signal, filtering and amplifying, carrying out analog-to-digital conversion, carrying out multi-stage orthogonal down-conversion and decimation filtering, storing, carrying out constant false alarm rate inspection, carrying out carrier synchronization, carrying out matched filtering, carrying out code element synchronization, carrying out whitening filtering, and carrying out demodulation decoding. The receiver comprises a radio frequency front-end processing module and a baseband signal processing module. wherein the radio frequency front-end processing module is used for performing intermediate frequency filtering and power amplification, radio frequency sampling, orthogonal down-conversion and decimation filtering processing on a received radio frequency signal to obtain abaseband signal, and the baseband signal processing module is used for performing detection, synchronization and demodulation decoding on an AIS message in the AIS baseband signal. The method has thetechnical characteristics of excellent demodulation performance, resource saving and collision signal processing.

The invention discloses an Internet-of-vehicles backoff method and a device based on a sender packet loss distinguishing mechanism, and the method comprises the steps: dynamically adjusting an observation interval according to the speed of a vehicle, so as to enable the observation interval to be inversely proportional to the speed of the vehicle, and taking an average value of the observation interval at this time and the observation interval at the last time as the number of surrounding nodes; firstly, constructing a collision probability prediction model and a weak signal packet loss probability model under an error channel, and then calculating a collision packet loss probability and a weak signal packet loss probability; connecting points with equal collision packet loss probability and weak signal packet loss probability into a packet loss distinguishing curve, comparing coordinate points representing the number of surrounding nodes and the signal-to-noise ratio when the previousframe of data is sent with the packet loss distinguishing curve, and distinguishing the packet loss type of the previous frame of data; and sending the data according to the packet loss type of the previous frame of data. The packet loss judgment accuracy is high, the throughput is improved, the network delay is reduced, the channel stability is ensured, and the method is suitable for scenes withdifferent vehicle densities.

The invention discloses an emergent nodal point power splitting method in multicast network which is based on regenerated network code in wireless communication technology filed. In the invention, as for information source terminals, two information sources s1, s2,at the same time, send broadcast signals to a relay, r and information sinks d1, d2 in a first time slot; the information sink d1 receives the signals from the information source s1 and the information sink d2 receives the signals from the information source s2; the relay r receives the aliasing signals of information sources s1 and s2; the information source power is split according to the known situations of counting channel information and instant s1 r and s2 r channel information; the relay node carries on the maximum likelihood decoding process to the aliasing signals sent by the two information sources in the first time slot; complex field totaling process is carried on to the two signals and the power is separately split for the known situations of counting channel information and instant s1 r and s2 r channel information. The method of the invention can reduce the transmission delay of the system to reduce the frame error rate of the system and improve the thruput of the system.

In a mobile communication system 100 of the third generation CDMA type. A base station control apparatus 1 controls a transmission power of an opponent communication apparatus by means of measuring a FER within a predetermined segment, averaging plural pieces of quality information per frame, producing a translation table 40c by means of associating the FER acquired by the measurement and average frame quality information acquired by the averaging, estimating an estimated FER corresponding to the quality information per frame from the translation table 40c, and controlling a target receive power threshold based on the estimated FER and a target FER stored in advance, thereby quickly carrying out the transmission power control, improving the data quality of a lower layer, maintaining the data quality as constant, and increasing the throughput.

The inventions provides a method of improving the aerial transmission quality of CDMA signals, assuring the alignment of forward service frame time of transmission signal in CDMA system, and its character: it includes the steps: obtaining system time on a base station controller BSC from any one service frame of the transmission signal and calculating a sequence number of the forward service frame; comparing the sequence number with an expected sequence number of forward service frame, calculated by the system time obtained by a base station transceiver BTS; judging whether to write the forward service frame in chips, discard or write in buffer region, thus assuring the strict alignment of transmission time of the forward service frame to improve the aerial transmission quality of the signal and aerial compensatory transmission quality.

The invention discloses a channel reservation method based on a double busy tone mechanism in a wireless self-organizing network. Aiming at three conditions that network nodes (comprising transmitting nodes and receiving nodes) transmit and receive non-real-time data packets or transmit and receive a first real-time data packet, the network nodes transmit or receive the second and the following real-time packets, and the nodes monitor the real-time busy tone of transmission (RBTt) or real-time busy tone of reception (RBTr) when the adjacent node is started, channel reservation information is broadcast by the double busy tone mechanism, so that the real-time traffic can acquire the right to use the channel in advance, thus improving the success rate of channel reservation, greatly reducing the frame error rate of real-time packet transmission, and ensuring the service quality of the real-time traffic.

The invention discloses a method for reliably transmitting a real-time service in a wireless Ad Hoc network. The method aims at the following circumstances that: a node B receives a real-time service data packet RPK sent by a real-time service sending node A or receives a special ACK packet RACK received by a real-time service receiving node A acknowledgement RPK; a non-real time service node Btx sends DPK to Brx or the real-time service node A sends a first RPK to the A; and the real-time service sending node sends a second real-time service data packet, subsequent real-time service data packets and the like. By acquiring channel permission for the real-time service in the Ad Hoc network in advance, the transmission reliability is improved and the frame error rate in packet transmission is reduced.

The invention relates to a decoding system of a low-density parity-check code, belonging to the field of communication technology. The decoding system of the low-density parity-check code comprises a plurality of decoding treatment devices, a first storage unit, a second storage unit, a decoding treatment device interleaving network and an interation stopping treatment device, wherein each decoding treatment device comprises a first alternative selector, an exclusive or arithmetic unit, a bit imformation arithmetic unit, a check node imformation arithmetic unit and an imformation node posterior probability likelihood ratio arithmetic unit, the check node imformation arithmetic unit comprises a buffer, a first comparator, a first register, a second alternative selector, a second register, a second comparator, a decoding post correcting device, a second cutoff arithmetic unit and a second complementary code converter, and the decoding post correcting device comprises n+1 comparison units, n subtraction units, a limiter and a zero setting device. By adding the decoding post correcting device, the invention remarkably lowers the bit error rate and the frame error rate, simplifies the interation stopping treatment device and saves the hardware resource consumption of the decoding system.

The invention discloses a modulation method based on a multiple-input multiple-output wireless communication system and a wireless device. In the method, code blocks are obtained by coding data information to be sent by a sending end, modulation symbols are obtained by modulating each code block, each modulation symbol is scheduled into each symbol group, a symbol group matrix is formed by takingeach symbol group as each row, and a symbol group matrix after the rotating modulation is obtained by carrying out the rotating modulation to the modulation symbols in the symbol groups according to a set rotating angle; and spiral layering interwoven treatment is carried out to the modulation symbols in columns aiming at each column in the symbol group matrix after the rotating modulation by thesending end, then the modulation symbol in the column after the spiral layering interwoven treatment is scheduled into one or more than one antenna group, and inversed interwoven treatment is carriedout respectively to a Q way signal component of the modulation signal in each antenna group. The error rate and the frame error rate are reduced by the method, and the channel capacity in a fading channel is approached.

A method, mobile device, network device, system, and software are devised for soft value scaling with a single antenna interference cancellation (SAIC) receiver, or with an interference rejection combining (IRC) receiver, in an unsynchronized network. A signal is received having interference that is caused by a non-synchronized network. A desired power level of that signal is calculated. Then the desired power is compared to a total power of the signal, in order to identify a portion of a received burst having substantial interference. Then that portion of the received burst is weighted, to reduce its importance during decoding.

The invention discloses a hybrid automatic retransmission method for continuous variable quantum key distribution. A decoding calculation unit of a sending end performs error correction negotiation with a receiving end when performing coding calculation according to discrete data, a check matrix and check sub-data; and a check sub-calculation unit of the receiving end performs error correction negotiation with a sending end when performing check sub-calculation according to the discrete data and the check matrix. Compared with the prior art, the method has the following positive effects: in anactual CV-QKD system, due to the fact that quantum signals are very weak, the influence of channels on the quantum signals is very large, so that a conventional scheme adopting a fixed error correction matrix is relatively high in frame error rate. According to the hybrid automatic retransmission method for the continuous variable quantum key distribution, by adopting hybrid automatic retransmission, the frame error rate of the CV-QKD system can be reduced, so that the security code rate is improved.

The invention discloses an LT code decoding method for a short code length system, and the method is an improved decoding method based on a BP (Belief Propagation) algorithm. The method comprises thefollowing steps: 1, performing system LT code encoding on an information source bit information sequence and performing binary phase shift keying (Binary Phase Shift Keying) on the information sourcebit information sequence; wirelessly transmitting the modulation symbol sequence to a receiver, enabling a receiver demodulator to adopt a traditional demodulation method to obtain channel log-likelihood ratio information of a system LT code coding bit, enabling a receiver LT decoder to adopt a BP decoding algorithm to decode, and after the BP algorithm is completed, enabling the receiver LT decoder to decode the channel log-likelihood ratio information of the system LT code coding bit. The receiver calculates the soft information of the coded bits, resorts and judges the soft information, andfinds out a minimum weighted Hamming distance by performing bit flipping on a bit sequence obtained by judgment, thereby obtaining a finally received information sequence. Compared with a traditionalBP decoding algorithm, the improved decoding method provided by the invention has the advantages that the soft information of the coded bits is fully utilized, so that the frame error rate (FER) canbe further reduced, and the purpose of reliable transmission is achieved.

The invention belongs to the field of underwater acoustic communication, and discloses an underwater acoustic communication adaptive modulation coding algorithm based on reinforcement learning, which autonomously explores the relationship between channel quality and a modulation coding scheme through a reinforcement learning algorithm, and establishes a reliable MCS switching threshold. The method comprises the following steps: firstly, defining a modulation and coding scheme, a signal-to-noise ratio and throughput as three elements state, action and reward of a Q table, initializing the Q table and an initial moment, randomly selecting the modulation and coding scheme to send a signal, receiving a demodulation signal and sending a feedback signal by a receiving end, updating the Q table by a reinforcement learning module according to the feedback information and selecting the modulation and coding scheme to send the signal according to the new Q table, and a receiving end receives the demodulation signal and sends a feedback signal, the above steps are repeated, and an accurate MCS switching threshold is obtained after multiple times of learning by a reinforcement learning module. The problem that a certain error exists in the MCS switching threshold obtained by giving a mathematical model according to simulation or a certain assumption in the traditional adaptive modulation coding technology is solved.