40results about How to "Guaranteed Bit Error Rate" patented technology

The invention discloses a zero intermediate frequency receiver and a method for eliminating the DC offset of the same. The receiver comprises a low-noise amplifier, a mixer, a first variable gain amplifier, an analogue-to-digital converter and a DC offset elimination device. The DC offset elimination device of the receiver combines analogue DC subtraction and digital DC subtraction by adopting an analogue feedback circuit to avoid complexity when an analogue circuit is independently used for DC subtraction, meet the requirement of a broadband receiver on the lowest flexibility and solve the problem that the dynamic analogue signal input range of the analogue-to-digital converter is required not to be wide when the digital DC subtraction is independently used. Experiments show that the DC offset can be relatively more completely eliminated from baseband signals by the method.

The invention discloses a method for lowering the OFDM system peak-to-average power ratio on the basis of virtual carrier reservation algorithms in the wireless communication technology field. The technical scheme comprises: obtaining respective time domain signals ci and x of a set special frequency domain signal Ci and a frequency domain signal which carries useful information through IFFT transformation, calculating the initial PAPR value of the x, recording the value as PAPRmin, setting an all-zero time domain signal cfinal, calculating the PAPR value of two values of x+cfinal+ci and x+cfinal-ci sequences, comparing with PAPRmin, storing the minimum PAPR value into PAPRmin, enabling a special time domain signal which satisfies the minimum PAPR value at present to be ctemp, modifying cfinal=cfinal+ctemp until i=L, and selecting a combination with the minimum PAPR to send. The method effectively lowers the complexity and bit error rate of peak-to-average power ratio calculation, and the system reliability is improved.

The invention relates to the channel error-correcting coding technique which can protect the Woven convolution code error-corrector in the TD-CDMA system. The invention replaces the Turbo code in present channel coding with the Woven convolution code error-corrector and encoder which uses a series of encoders to replace the internal and external encoders of step-connected code. The Woven convolution code uses two steps of coding structure, while the iterated decoding structure is used for decoding. Since the simple convolution component code and the paralleling decoding structure are used in the invention, the time delay of decoding and the operational complexity are reduced markedly. So the Woven convolution code more fits the high-speed high-real time service to improve the property of system compared to the Turbo code.

The invention discloses a selection method for a routing backbone path based on network connectivity. The method specifically comprises the following steps: step 1, calculating the assistant connectivity probability from a source node to a destination node according to vehicle location information within the jurisdiction by a gateway; step 2, calculating the end-to-end delay d by the gateway; step 3, calculating the route hops H by the gateway; step 4, calculating a bit error rate BER by the gateway; step 5, taking the assistant connectivity probability as a target function, taking the delay, the hops and the bit error rate as constraint conditions, and forming an optimization problem; step 6, using a routing genetic algorithm to obtain an optimal solution, that is a backbone route; step 7, adding the optimal solution to the header of a data packet; and step 8, if the thresholds Dth, Hth and BERth corresponding to the end-to-end delay d, the route hops H and the bit error rate BER required by QoS are invariable, then returning to step 7, otherwise, returning to step 1. A crossroad based routing mechanism proposed by the invention guarantees the transmission delay, bit error rate and other QoS indexes by a higher network connectivity probability.

The invention provides a new MIMO-OFDM system packet self-adaptive modulation method. The method is characterized by comprising the following steps: for a MIMO-OFDM system adopting the spatial frequency packet coding, performing packet usage on the antenna by considering a codon structure of the spatial frequency coding and a channel quality to a receiver from each antenna in a unified way, independently adopting appropriate different linear digital modulation technologies for different antenna groups according to the channel quality, thereby enabling the receiver to perform correct spatial frequency decoding for each packet and to realize the independent digital demodulation. Through the technical scheme provided by the invention, the system can simply realize the self-adaptive modulationand demodulation by using the codon structure, and higher spectrum efficiency can be provided as far as possible when the required bit error rate is satisfied. The method provided by the invention ismainly used for a mobile communication system and a downlink communication link of other wireless communication network, namely, the communication link from a base station to a user, but not excludethe application in an uplink.

The invention provides a mobile underwater acoustic communication method, which generates a DPLFM signal required for communication, modulates data to be transmitted, receives the signal through a mobile underwater acoustic communication channel at a receiving end, performs virtual time reversal processing, and finally filters and demodulates the received signal after the virtual time reversal. The invention uses PLFM signal to replace LFM signal as carrier signal of underwater acoustic communication system, and combines piecewise linear frequency modulation and FDM technology, so that spectrum utilization ratio and data rate of traditional LFM underwater acoustic communication method are effectively improved. At that same time, when the relative motion speed of the communication transmitend and the receiving end is low, the invention doe not need Doppler frequency shift compensation, and the performance of the OFDM underwater acoustic communication system compensated by the Doppler frequency shift can be consistent with or even better, and the invention has the advantage of simple algorithm.

The invention relates to an underwater acoustic communication link adaptive configuration method based on orthogonal signal division multiplexing modulation, which comprises the following steps of: setting sets of OSDM modulation schemes under different coding lengths of Hadamard, and calculating a signal-to-noise ratio interval under a given error rate; adding a signal segment for environment cognition by a sending end while sending an RTS request channel; and after receiving the RTS, by a receiving end, completing cognition on the environment and calculating and receiving channel related parameters such as a signal-to-noise ratio; by the receiving end, sending a CTS response, and feeding back the corresponding OSDM communication system to the sending end; and after the sending end receives the CTS, adjusting the OSDM communication system of the sending end according to the communication system information in the CTS, so that the corresponding DATA data is sent after the communication systems of the sending end and the receiving end are kept synchronous. Compared with link configuration directly using a single communication mode, the environment cognition link self-adaptive configuration method based on OSDM modulation is more suitable for a real underwater acoustic time-varying channel.

The invention discloses an LTE femtocell user pairing method with mode switch. User pairing is carried out according to dispatching cycles, a polling method is utilized to choose an unpaired femtocell user HUE as the first user in a pairing user group in each cycle, an inner layer is chosen to be paired with the HUE or a cross layer is chosen to be paired with a macro base station user MUE according to the strength of cross layer interference, the maximum pairing is carried out on the premise of guaranteeing the bit error rate, pairing is finished, and the femtocell can inform all paired users to send data in the next dispatching cycle. The LTE femtocell user pairing method can adaptively choose the inner layer of the HUE or the cross layer of the MUE to be paired through a signal to interference ratio threshold judgment method. When the average bit error ratio doesn't beyond an error bit ratio increasing control coefficient, pairing users are increased continuously. Furthermore, the LTE femtocell user pairing method improves the channel utilization rate of limited frequency bands and relieves the work stress of a macro base station through the femtocell on the premise guaranteeing the bit error ratio.

A method (10) of encapsulating digital communications traffic for transmission on an optical link, the method comprising: a. receiving an input digital communications signal having an input line code (12); b. performing clock and data recovery on the input digital communications signal to obtain input line coded digital communications traffic and a recovered clock signal (14); c. decoding the input digital communications traffic to obtain information bits and non- information bits (16); d. removing the non-information bits (18); e. adding service channel bits for monitoring or maintenance (20); f. assembling the service channel bits and information bits into frames (22); and g. line coding the assembled frames using an output line code to form an encapsulated digital communications signal for transmission on an optical link (24), wherein steps c. to g. are performed using the timing of the recovered clock signal. A communications network receiver configured to implement the method is also provided.

The invention discloses a new energy vehicle charging station cloud management platform, which comprises an adaptation module, a cloud storage module and a control center. Through the platform, the data of a charging pile can be visually known, there is no need for regular patrol inspection by operation and maintenance personnel, At the same time, the automatic control of charging pile equipment can be realized, and the control time has obvious advantages under the condition of ensuring the consistent control effect, so that the system can guarantee the bit error rate required by the system, and at the same time, the communication transmission efficiency can be improved as much as possible, and the operation and maintenance cost per unit time can be greatly improved.

The invention discloses a hybrid automatic repeat request method based on an improved effective signal-to-noise ratio. The method comprises the following steps: establishing a hybrid prediction model based on an HMM and an LSTM network; training a hybrid prediction model through the change data of the historical signal-to-noise ratio SNR, and obtaining the change trend of the effective signal-to-noise ratio ESNR of the channel at the next moment by using the trained hybrid prediction model; adjusting a check bit of a Hamming code according to the change trend of the effective signal-to-noise ratio ESNR and completing a data transmission process; in the transmission process, enabling the receiving end to carry out decoding and judging whether the decoding is successful or not: if the decoding is successful, continuing the transmission, if the decoding is failed, carrying out the retransmission, continuing to judge whether the decoding is successful or not, if the decoding is not successful and the number of retransmission times does not reach an upper limit value, continuing the retransmission of the data. According to the method, the bit error rate can be obviously reduced, the retransmission times are reduced, and the throughput rate of the system is improved.

The invention provides a QoS (Quality of Service) guaranteeing method based on cross-layer united resource optimization for a full IP (Internet Protocol) OFDMA (Orthogonal Frequency Division Multiple Access) communication system of 3G-LTE (3G Long Term Evolution). Three protocol layers including a physical layer, an MAC (Media Access Control) layer and a call admission control layer are considered so that the quality of service of a plurality of services under a full IP condition is guaranteed. The method comprises the following steps: power and bit rate distribution of the physical layer and restriction on an upper layer by the physical layer; equivalent bandwidth distribution on the MAC layer and restriction on a CAC layer by the MAC layer; design of a CAC scheme. According to the method, the problems in the prior art that the suitability of MAC layer dispatching is only met by trying to optimize parameters of the physical layer by cross-layer resource distribution, and the quantity of users accessing to the system is not limited by the proper CAC scheme are solved; the long-time-delay queuing of a data packet is avoided, the QoS of the users is guaranteed better, and the resource utilization rate is improved.

The invention discloses an LLR-BP decoder adaptive to code lengths. The LLR-BP decoder comprises an initial data buffer module, a check node processing module, an intermediate information storage module, a variable node processing module, a control module, an output cache module, and decoding determining module. In the Xilinx ISE14.7 environment, a partially parallel LDPC decoder structure is designed which uses an early termination iterative decoding strategy to reduce the number of iteration times of an algorithm. By using a limit taking method, the operation of a complex probability function in the LLR-BP decoding algorithm is implemented, thereby reducing the implementation complexity of the algorithm. On the premise of ensuring a bit error rate, the decoder improves decoding speed, reduces a hardware logic resource occupancy rate, and solves simultaneous decoding of multiple code lengths.

The invention provides a physical layer secure transmission method capable of resisting any number of eavesdropping antennas. According to the invention, precoding processing is carried out to resisteavesdroppers with any number of antennas or eavesdroppers with any number of cooperative nodes; legal receivers and transmitters do not need to share any key information. No matter how many antennasare used by an eavesdropper for eavesdropping, the bit error rate of the received confidential information can be ensured to be 0.5, high-strength physical layer secure transmission is achieved, the advantages of low power consumption, low complexity and low interference are achieved, physical layer secure communication of eavesdroppers of any multi-antenna can be achieved without any additional artificial noise or cooperative interference, and extra burden of a network or redundant interference to other users cannot be increased. In the communication process of the method, Alice and Bob of two legal communication parties need a protection area with the radius of R to surround themselves respectively, so that an eavesdropper Eve cannot enter the protection area to eavesdrop, and it is guaranteed that channels of the Eve are independent of the Alice and the Bob.

The invention provides a resource optimization method and device in baseband processing, and electronic equipment, and relates to the technical field of communication. The method and the device are applied to a DVB-T2 system sending end. The method comprises the following steps of acquiring data to be transmitted, writing the data to be transmitted into an RAM according to a cell interleaved writing rule, and reading the written data to be transmitted from the RAM according to a time interleaved output rule. According to the resource optimization method and device in the baseband processing, and the electronic equipment which are provided by the invention, cell interleaving and time interleaving are combined, so that the occupied RAM resources are reduced, and the running speed of the T2 system is improved.

The invention discloses a threshold determining method of a reader-writer of an ambient backscatter system. The method comprises the following steps: emitting source radio frequency signals to a surrounding environment by use of a radio frequency source; receiving the source radio frequency signals from the radio frequency source by use of an electronic tag; receiving the source radio frequency signals from the radio frequency source, radio frequency signals reflected by the electronic tag and noise signals in environment by use of the reader-writer; the reader-writer demodulating the actually received radio frequency signals; by use of the reader-writer, calculating average power of N continuous radio frequency signals which are demodulated by the reader-writer; respectively obtaining probability distribution functions of the average power of the N continuous radio frequency signals which are demodulated by the reader-writer when the electronic tag is at a non-reflection state and a reflection state; respectively calculating an error bit rate when the electronic labels are at the reflection state or the non-reflection state; and respectively obtaining a first threshold and a second threshold of the reader-writer. The determining method provided by the invention can reduce the error rate of ambient backscatter.