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The following topics are dealt with: signal processing; cognitive radios and networks; communication systems; network protocols and performance; ad hoc sensor network; telecommunication security; and mobile computing systems and technologies.
System identification concepts play a key role in adaptive signal processing applications like communication channel estimation, acoustic echo cancellation, active noise control, and adaptive feedback cancellation. In the development of such systems, one would often like to know what kind of performance could be expected and how it depends on the filter length before actually committing the adaptive...
Time domain predistortion algorithms have some defects. In this paper, directly taking the outband spectrum leakage suppressing as the optimization object, we propose an algorithm for parameters identification of an predistorter by applying improved PSO (particle swarm optimization) algorithm with great generalization optimization capacity. Aiming at the problem of a large number of parameters, the...
A new perfect signal-binary complementary array pair set is presented under aperiodic correlation condition. The aperiodic correlation and equivalent transformation properties are proposed. The construction methods of 2-D complementary array pair set which is based on binary complementary sequence pairs set is presented, and the change dimension property is proved. Several binary complementary array...
This paper presents a matching method for a antenna element. The proposed antenna is comprised of a equiangular spiral antenna, Archimedean antenna and two stubs, which printed on a Rogers Duroid 5880 substrate with εr = 2.2 and a thickness of 1.52 mm. The matching problem between antenna and a diode is well solved. The proposed antenna, covering the frequencies in the range from 0.6 GHz to 10 GHz,...
In this paper, a baseband predistortion scheme is applied and implemented into real-time FPGA to linearize a Doherty power amplifier for wireless applications. The base-band behavioral models of the Doherty amplifier are based on the Memory Polynomial approach and the direct learning method is applied to estimate the model of the predistorter. For our Doherty power amplifier with a 256-QAM I/Q input...
The properties of rateless codes make it very suitable for all types of broadcast systems. In this paper, the rateless codes are adopted in the Next Generation Broadcast Network Wireless (NGB-W) system and two cooperative rateless codes are proposed for two different scenarios in NGB-W system. In the first scenario, different degree distribution functions are adopted for rateless codes encoding in...
This paper considers the combination between correlation-mapping based spreading and orthogonal frequency and code division multiplexing (OFCDM) systems. The proposed system makes use of the correlated channels to spread the transmitted bits in time and frequency domains of OFCDM systems. The input bits are regained by calculating the correlation values of the received bits. This method inherits the...
Orthogonal frequency division multiplexing (OFDM) has attracted much attention as it is convenient to implement and robust to multiple path fading. However, the system performance of OFDM will be degraded seriously in high-speed wireless communications, since it is much sensitive to severe inter-carrier interference (ICI) caused by high-speed vehicles. Recently, a novel modified OFDM system, called...
In this paper, an order reduction maximum likelihood (OR-ML) algorithm for spatial modulation systems is proposed to reduce the receiver complexity. The proposed algorithm relies on a smaller order neighbourhood constellation which is relative to the conventional mapping constellation, where the active transmitting antenna indices or the possible quadrant transmission symbols locate in is obtained...
Recently, subcarrier index modulation (SIM) combined orthogonal frequency division multiplexing (OFDM) has been developed as a new transmission technique. In this paper, we study a coded SIM-OFDM scheme where an encoder and decoder are employed. The transmitted bits are modulated onto the constellation points after coding. At the receiver, we provide a ML algorithms detecting method to get the soft...
In this paper, the convergence-enhanced subspace channel estimation technique is investigated for MIMO-OFDM systems. The perturbation of noise subspace is inversely proportional to the number of OFDM symbols. Using the block circular property of the channel matrix, we propose the cyclic repetition method (CRM) to generate a group of equivalent signals for each OFDM symbol. The subspace channel estimation...
This paper proposed a novel approach of the wavelet packet transform based CME on interference suppression technology in Direct-Sequence Spread Spectrum system (DSSS). The algorithm is executed in three steps: First, we analyze the input signal by wavelet packet transform to appear the interference in the transform domain. Second, the CME algorithms complete the interference detection and delete interference...
For multi-source relay-based cooperative communications, it is widely believed that Complex Field Network Coding (CFNC) achieves better throughput performance than Physical-layer Network Coding (PNC). However, traditional CFNC schemes suffer a considerable loss on the performance of symbol to error ratio (SER) and peak-to-average power ratio (PAPR) as the number of source nodes increases. In this...
Block diagonalization (BD) is a well-known linear precoding scheme for multi-user multiple-input multiple-output (MU-MIMO) downlink transmission. BD precoding achieves good performance but results in high computational complexity overheads due to two singular value decomposition (SVD) operations for each user. By replacing the first SVD operation with a less complex solution, the QR decomposition...
This paper is concerned with the iteration identification algorithm for Hammerstein model with complex-valued input for the fact that the existing algorithms are not valid for complex input. Based on the stochastic gradient algorithm, the extended stochastic gradient algorithm is proposed by defining new cost function for complex input. The extended hierarchical multi-innovation stochastic gradient...
In this paper, we develop a novel codebook with low storage and complexity. The proposed codebook is constructed by cyclically shifting certain unit-norm vectors which satisfy the mutually unbiased condition. Moreover, an FFT-based algorithm, whose time complexity increases logarithmically with the number of transmit antennas, is proposed. Simulation results show that the proposed scheme is very suitable...
In this paper, we propose a new improved TH precoding algorithm, which intends to solve the problem of high bit error rate (BER) from traditional THP algorithm when the channel is in bad condition, and compare the performance with different classic ZF-THP and MMSE-THP. Also the conclusion is verified by emulation. Based on the Precoding module algebra, we proposed the Reduce Grid Algorithm which has...
When the electromagnetic waves propagate over the sea surface, there exists reflection, scattering and diffraction. Impact of sea clutter to the communication link is an important issue to evaluate and demonstrate. In this paper, we simulate the communication transmitter and receiver and use the theory of random bridge to build a random multipath channel model of the sea surface. Combined with typical...
To study the electromagnetic environment above the board of ship when high-altitude nuclear electromagnetic pulse (HEMP) radiated to it, a new method based on signal reconstruction is presented. By adopting FFT method, the HEMP signal is decomposed into a sum of sine continuous waves of different frequencies, and the amplitude response of the ship at each frequency, namely the amplitude spectrum can...
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