The invention relates to a compressed sensing PIE system based on space-frequency coding. In a transmitter, a channel encoder, a modulator, an orthogonal converter, a symbol interleaver, a serial-to-parallel converter and a space-frequency encoder are successively connected in series, the space-frequency encoder is connected with two subcarrier mapping devices of the same structure, and each subcarrier mapping device is successively connected with an up sampler, a reverse discrete Fourier transformer, a cyclic prefix adder, a parallel-to-serial converter, a D/A conversion and RF emitter and an emission antenna. A receiver comprises a reception antenna, an RF front-end converter, an A/D converter, a Doppler frequency offset estimator, a Doppler frequency offset compensator, a cyclic prefix remover, a discrete Fourier transformer, a compressed sensing interference eliminator, a frequency-domain down sampler, a channel estimator, a space-frequency decoder, a symbolic solution interleaver, a reverse orthogonal converter and a channel decoder successively in serial connection. The compressed sensing algorithm can be directly utilized to reconstruct pulse signals of a range finder and converts the pulse signals to the frequency domain for elimination, and thus, the pulse signals of the range finder are effectively inhibited.

Compressed sensing PIE (Pulse Interference Elimination) system based on space-frequency coding

A device may select a sector of a network on which to perform network traffic offloading based on a sector loading metric relating to an imbalance of loading of a set of cells of the sector. The device may identify a loaded cell of the sector based on one or more call admission metrics or one or more cell congestion metrics. The device may identify a less loaded neighbor (LLN) cell for the loaded cell. The device may cause one or more cell configuration alterations relating to causing network traffic to be offloaded from the loaded cell to the LLN cell.

Real-time load balancing for a network

The invention discloses a time type network covert channel construction method based on discrete wavelet transform, and belongs to the technical field of network information security. According to the time type network covert channel construction method disclosed by the invention, a secret message is embedded in a wavelet domain coefficient of a normal IPD sequence, and the embedding position and intensity are controlled to reduce the time domain changes to the original carrier and the properties of the original carrier as much as possible; and the generated covert communication data streams have normal rules and features and better anti-detection property. Meanwhile, the secret message bits are embedded in a part of approximation coefficients of wavelet decomposition by adopting the odd-even quantification method, and the network noise interference can be resisted to a certain extent without importing additional synchronization cost, and the robustness is relatively good.

Time type network covert channel construction method based on discrete wavelet transform

The present invention provides an ACO-OFDM wireless optical communication system channel estimation method based on compressed sensing, and belongs to the field of intensity modulation optical communication. The channel estimation method is used to solve the problem that during pilot based channel estimation, a pilot symbol causes a bandwidth utilization rate to be reduced. According to the method provided by the present invention, channel estimation technology based on the compressed sensing is combined with the ACO-OFDM system. Firstly, the pilot is enabled to have Hermitian symmetry, a pilot allocation scheme is optimized by minimizing a DFT sub-matrix cross-correlation squared sum, and an ACO-OFDM system pilot allocation optimization algorithm is provided. Then, a channel response is estimated by using an improved variable step sparse degree adaptive matching tracking algorithm, the improved algorithm can improve estimation accuracy and calculation speed. Finally, an iterative correction algorithm is used to further improve the estimation accuracy. Compared with the traditional pilot based channel estimation method, the method can effectively reduce the number of pilot symbols, and improve the system bandwidth utilization rate.

ACO-OFDM system channel estimation method based on compressed sensing

The invention provides an improved in-band noise reduction DFT channel estimation algorithm. As noise still exists in the traditional DFT algorithm channel estimation value, the signal has a large power change range, the demodulated channel is distorted possibly, transmission of the signal has serious time domain dispersion, and in order to reduce the influences, the algorithm of the invention processes DFT channel estimation-based hDFT(n) with n in a range of 0 to Ng, the remaining remains unchanged, and noise interference is filtered.

Improved in-band noise reduction DFT channel estimation algorithm

The invention discloses a mobility load balancing method based on an AHP (Analytical Hierarchy Process) in an LTE system. The method mainly comprises the steps of selection of an optimal load transfer cell and determination of optimal CIO (Cell Independent Offset) parameters. According to the method, four modules namely a cell state detection module (1), a user-cell matching pair generation module (2), a load distribution module (3) and a balancing module (4) are adopted, wherein the cell state detection module is mainly used for judging a cell load state and initiating load balancing if a cell is overloaded; the user-cell matching pair generation module is mainly used for selecting an optimal transfer cell of a user through an AHP algorithm; the load distribution module is mainly used for pre-distributing the load quantities of the overloaded part of the overloaded cell to each target cell before the CIO parameters are adjusted; the load of each target cell is smaller, the distributed load quantities are larger; the balancing module is mainly used for adjusting the CIO through a variable step; when each target cell completely receives the distributed load quantities, the optimal CIO of the cell is obtained.

Mobility load balancing method based on AHP (Analytical Hierarchy Process) in LTE system

The invention discloses a short-wave OFDM (Orthogonal Frequency Division Multiplexing) interference suppression joint channel estimation method based on compressed sensing, relating to the field of short-wave communication and the technical field of mobile communication. The method comprises the following steps: step 1, acquiring reception values YM*1 of M pilot signals transmitted from a transmitting end by a receiving end; step 2, performing strong single-tone interference suppression; and step 3, reconstructing a short-wave channel h according to a reconstruction algorithm MCoSaMP, thereby obtaining the short-wave channel frequency domain response H. According to the channel estimation method provided by the invention, fewer pilot symbols can be used compared with those in a traditional channel estimation method, and the frequency spectrum utilization rate is improved. Moreover, channel estimation error can be effectively reduced by suppressing strong single-tone interference in the short-wave channel, and the channel estimation performance is improved.

Short-wave OFDM (Orthogonal Frequency Division Multiplexing) interference suppression joint channel estimation method based on compressed sensing

The invention discloses a short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference. The method includes the steps: firstly, estimating an initial estimation value of a pilot frequency in a channel by the aid of an LS (list scheduling) algorithm, then performing a primary noise filtration for the initial estimation value by the aid of DFT (discrete Fourier transformation) channel estimation algorithm principle, namely, the length of a circulation prefix code is larger than channel impact response, filtering noise except a circulation prefix by the aid of a method that an estimation value larger than the length of the circulation prefix code is reset zero, finally, performing a secondary noise filtration for the initial estimation value by leading in a threshold value, acquiring a final estimation value at the pilot frequency by performing zero setting for signals smaller than the threshold value and keeping invariable for the portions larger than the threshold value, then performing interpolation for pilot frequency estimation according to interpolation modes to obtain estimation of the whole channel, and performing DFT for channel estimation of a time domain to obtain channel estimation of a frequency domain. The channel estimation perform is improved, the pilot frequency is of a comb-like pilot frequency structure, and rapid fading of short wave signals is effectively restrained.

Short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference

The invention discloses a wavelet-denoising-based SC-FDE channel estimation method in a short wave channel. The wavelet-denoising-based SC-FDE channel estimation method includes the steps of firstly, partitioning sent data, periodically inserting pilot frequency between data blocks, extracting information at the pilot frequency positions at a receiving end, and estimating channel frequency responses at the pilot frequency with an LS algorithm; secondly, carrying out IDFT on obtained estimation values to be in a time domain, factoring the estimation values in a wavelet domain according to a multi-Mallat algorithm, filtering out noise with a threshold denoising method, and reconstructing noise-eliminated signals; finally, carrying out interpolation zero filling on the reconstructed signals, carrying out DFT on the reconstructed signals to be in a frequency domain, accordingly obtaining all the channel frequency responses, and completing channel estimation. According to the wavelet-denoising-based SC-FDE channel estimation method in the short wave channel, the LS estimation left noise is eliminated with a wavelet denoising method, influences of the noise are further suppressed accordingly, the system bit error rate is lowered, and the system performance is improved.

Meng Tingting

Papers

Mobility load balancing method based on AHP (Analytical Hierarchy Process) in LTE system

Short-wave OFDM (Orthogonal Frequency Division Multiplexing) interference suppression joint channel estimation method based on compressed sensing

Short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference

Wavelet-denoising-based SC-FDE channel estimation method in short wave channel