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

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 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.

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 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.

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 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.

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 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 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.