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In this paper, fractal theory is successfully applied to the analysis of fractal properties of Mandarin speech. First, a new algorithm of the arithmetical progression scales gridding dimension, based on the conventional Box Dimension, is presented to reduce the computational cost. Second, the distribution laws of fractal dimension of Mandarin speech have been obtained by calculating and statistically analyzing the arithmetical progression scales gridding dimension of 21 consonants and 38 vowels of Mandarin speech. The preliminary results in our experiment show that Mandarin speech has the scale-invariant property and that the arithmetical progression scales gridding dimension can indicate the complexity and irregularity degree of the waveform of Mandarin speech signals. The novel discoveries in our studies imply that fractal theory has a good potential in the field of speech signals processing.

A modified Itakura speech distortion measure is presented in this paper. This new modified Itakura speech distortion (called M-Itakura) has taken into account auditory properties of human beings. In the algorithm of the M-Itakura measure, the speech signal is processed using results of psychoacousitic measurements, which include critical band analysis, equal-loudness pre-emphasis and intensity–loudness power law, and the short-time speech power spectrum is converted to auditory perceptual spectrum. Preliminary experiments in comparison with the Itakura measure have been done. Simulation results have shown an improvement of the M-Itakura measure over the conventional Itakura measure and the M-Itakura measure is more consistent with subjective assessment of speech quality.

Radar altimeter is applied to measure the height of an aircraft above the ground in terrain contour matching system(TERCOM). The total performance of the TERCOM is almost determined by the height-measuring algorithms embeded in the radar altimter. When facing a complex terrain area with a large degree of fluctuation, the traditional radar altimetry height-measuring algorithm performance will be greatly affected,for the reason that wide-beam pulse radar altimeter illuminates widely. In order to solve the problem, this paper proposes a new algorithm named average-height algorithm,and the detailed derivation is carried out. Simulation and flying test has shown that it has good performance and can be applied to any kind of terrain.

A simulation model for pulse radar altimeter video echo is proposed, the calculation of all parameters in this simulation model and the correlative arithmetic of echo simulation based on this model are discussed in detail. The simulation is completed with the using of real digital elevation graphs as data source. The results shows the validity of the proposed model and simulation method.

A new unambiguous tracking technique for the sine-binary offset carrier (Sin-BOC(1,1)) and multiplexed binary offset carrier (MBOC(6,1,1/11)) signals is presented. This technique substitutes the combination of the auto-correlation function (ACF) and the absolute value of ACF (AACF) for the ACF in the coherent Early-minus-Late (EML) architecture loop. It can completely removes the side-peaks from the ACF of Sin-BOC(1,1) and MBOC(6,1,1/11) while still keeping the sharp main-peak, which maintains the multipath rejection property of the BOC modulation. The performances in terms of multipath mitigation are evaluated.

A MMSE-based blind multi-user detection algorithm for multilevel frequency shift keying/fast frequency hopping multiply access asynchronous communication system is proposed, detector implements blind detection without prior knowledge of address of co-channel interference users. The detector exploits energies of user signal and implement decisions through distinguish most sum row and its minimum mean square error (MMSE) of decode T-F matrix. The performance of proposed detector is analyzed and compared with other asynchronous multi-user detector. Simulation results show that the proposed asynchronous multi-user detector has a strong capability of resistant false alarm and deletion; meanwhile, it has low complication

In this paper, we propose the scheme that the technology of ultra-wide band is used in hybrid wireless networks and establish the corresponding network model. According to the limit theory, we derive the analytical expressions of capacity in hybrid wireless networks. Simulation results show that the hybrid wireless network formed by adding base stations within an ad hoc network is an effective way to improve the network capacity, while the technology of ultra-wide band used in hybrid wireless networks can enhance the capacity performance to some extent

Network capacity is a key characteristic to evaluate the performance of wireless networks. The capacity of wireless ad hoc network that is a rising network model has been discussed widely. The goal of this paper is to study about the capacity of wireless relay network. We assume that at most n/sub s/ source nodes transmitting signal simultaneously in the network and derive the upper and lower bound on the capacity of this kind network model. Finally, the capacity region of wireless relay network by simulations in the idealized condition is given.

The network capacity is a very important parameter to evaluate the performance of ad hoc network. In this paper, the objective of our research is how to obtain the large capacity in ad hoc network. We establish the ad hoc network model from the novel point of view and consider the network capacity could achieve the maximum when the network resources (including area, bandwidth, power, load and so on) are used up minimally on the successful transmission condition. We set up the equation that makes the network resource consumed minimally and solve the problems of network capacity and the corresponding routing policy by the graph theory. Subsequently, we improve on these algorithms that are proved more efficient through the simulation experiment. Finally, the conclusion that the network capacity should combine with the routing policy is made.

The hybrid wireless network is a novel network model, where a sparse network of base stations is placed within an ad hoc network. Throughput capacity of hybrid wireless network is an important parameter to evaluate the performance of this network model. In this paper, we propose a general framework to analyze the capacity of hybrid wireless network in CDMA scheme by Markov chain approach and derive the mathematical analytical expressions on the capacity of the finite-population system under some routing policy. Moreover, simulation results show that hybrid wireless network could be a tradeoff between centrally controlled networks and ad hoc network, which have the directive significance to network designers

The perceptual spectrum distortion (PSD), based on the auditory properties of a human being, is presented as a speech distortion measure. The PSD measure calculates the speech distortion distance by simulating the auditory properties of a human being and converting the short-time speech power spectrum to the auditory perceptual spectrum. Preliminary simulative experiments in comparison with Itakura's measure have been done. The results of experiments show that the PSD measure is a preferable speech distortion measure which is consistent with a subjective assessment of speech quality.

The concept and algorithm of the speech wave abnormal index (SWAI) is presented to describe the damaged degree of speech signals, which are disturbed by noise or/and crosstalk speech. By using the method of parallel processing to estimate the pitch periods of speech in the time domain, an algorithm for calculating the SWAI is put forward. Theoretical analysis and experimental results show that the SWAI not only can be applied to detect crosstalk speech, but also is an important feature parameter of speech signals in objective speech quality assessment.