Yongjun Sun

An OFDM modulation recognition algorithm based on spectrum analysis

This paper presents the feature of energy distribution parameters for power spectrum. Then based on the spectrum analysis, an OFDM recognition method is proposed using the energy distribution parameter P, the kurtosis coefficient of the power spectrum and the power spectrum parameter R. Power spectrum is preprocessed to eliminate the effect of signal bandwidth, sampling rate, carrier frequency and FFT points on the threshold of identification. This method does not require any prior knowledge (such as symbol rate, carrier frequency, etc.), and the IF signal can be directly processed. Simulation results show that the extracted parameters have good performances in both AWGN and Rayleigh fading channel. The recognition accuracy is up to 97% with a signal to noise ratio (SNR) at 10dB.

Blind Equalization Algorithm for Different Eigenvalue Spread Channels

The performance of blind equalization algorithm is closely related to the characteristics of the channel. Eigenvalue spread of the channel can reflect the influence of the channel on the input signal. The paper presents a method to distinguish eigenvalue spread of the wireless channel by the correlation coefficient of the input vector. For channels with different eigenvalue spread, based on the consideration of the complexity and the performance, different blind equalization algorithms are chosen. At the same time a decorrelation blind equalization algorithm is proposed. Simulations verify the effectiveness of the proposed algorithms.

Blind Equalization Based on Data Reuse and Reliability Labeling

In the absence of a training sequence, blind equalization algorithm usually takes thousands or even tens of thousands symbols to converge, which is especially evident when the channel is severely distorted. When the short data is required to achieve equalization, the current blind equalization algorithms will be difficult to converge. This letter presents a short data reuse blind equalization algorithm based on reliability labeling. If the output symbol corresponding to the same input is labeled twice with reliability during the process of the current and last data reuse, the algorithm will switches to the decision-directed model automatically. At the same time the letter gives a simple way for model switching by a look-up table. Simulations show that the proposed algorithm performs better compared with Modified Constant Modulus Algorithm with long data.

A Cooperative Peer-to-Peer Repair Scheme Based on Hybrid Network Coding

Cooperative peer-to-peer (P2P) repair (CPR) is an efficient way to recover the lost packets in wireless multicast system. Using network coding in CPR can further improve the transmission efficiency. However, there will be high computational overhead for random linear network coding and high optimization complexity for XOR-based network coding when the number of multicast data packet is relatively large. With regard to this problem, we propose a hybrid network coding based cooperative P2P repair scheme (HNC-CPR) with two efficient and light-weight scheduling algorithms. The HNC-CPR scheme can reduce the computational complexity while ensuring high transmission efficiency. Finally, example analyses and simulations demonstrate the efficiency and low-complexity of HNC-CPR.

Suppression of Sinusoidal Frequency Modulation Interference in DSSS Systems

For the wideband nonstationary sinusoidal frequency modulation (SFM) interference in DSSS systems, the paper proposes a method to estimate partial parameters of the interference, and then an interference suppression algorithm is developed. The performance of the algorithm is analyzed. Simulations show that the algorithm can efficiently suppress the SFM interference.