scholarly journals Channel Identification for OFDM Communication System in Frequency Domain

10.5772/36191 ◽  
2012 ◽  
Author(s):  
Lianming Sun
Keyword(s):  
Frequency Domain ◽  
Communication System ◽  
Channel Identification

Orthogonal Pulse Design Based on Sinusoidal and Cosinusoidal Functions

2014 ◽  
Vol 556-562 ◽  
pp. 1683-1686 ◽  
Author(s):  
Heng Jun Zhou ◽  
Zhi Yong Zhao ◽  
Xi Guo Liu ◽  
Zhong Yang Mao
Keyword(s):  
Information Transmission ◽  
Frequency Domain ◽  
Communication System ◽  
Bandwidth Efficiency ◽  
Parameter Setting ◽  
Pulse Design ◽  
Pulse Solution ◽  
Relative Bandwidth ◽  
Designing Method

In order to improve the bandwidth efficiency for the communication system effectively, a designing method for orthogonal pulse based sinusoidal and cosinusoidal functions is put forward. The orthogonal pulse is designed by parameter setting, sub-band division, parameter solution and pulse solution from the point signal character. The orthogonal pulse’s spectrum is mixed or overlapped in frequency domain. It can not only be formed little relative bandwidth signal, but also large relative bandwidth signal. The system bandwidth efficiency can reach 2Baud/Hz when the orthogonal pulse is used in information transmission.

scholarly journals Research on Spectrum Optimization Technology for a Wireless Communication System

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 34 ◽  
Author(s):  
Mingxin Liu ◽  
Wei Xue ◽  
Peisong Jia ◽  
Sergey B. Makarov ◽  
Beiming Li
Keyword(s):  
Energy Spectrum ◽  
Wireless Communication ◽  
Frequency Domain ◽  
Time Domain ◽  
Communication System ◽  
Energy Ratio ◽  
Main Lobe ◽  
General Function ◽  
Baseband Signal ◽  
Energy Leakage

In this study, the principle of minimum spectral energy leakage is applied, and the mathematical model is also established by the general function through adding different constraints. To allow the target baseband signal to have a high-quality time-domain representation, it is assumed that the baseband signal is an even function. The time-domain waveform has symmetry about the y-axis, and the objective function is obtained by Fourier series approximation. The frequency-domain characteristics of the baseband signals are obtained by adding the energy limitation condition and the boundary restriction condition. Limit a point at the appropriate position of the main lobe of the normalized energy spectral density function, and at the same time, limit the appropriate point at the first side lobe. The changes of the points modified the whole characteristic of the frequency-domain. To more conveniently compare the characteristics of the signal under different constraints, according to the symmetry of the frequency-domain of the signal, the normalized energy spectrum main lobe energy ratio is defined as a parameter, and thereby the spectral performance of the signal is discriminated by the size of this parameter. Through comparative analysis, the signal with the frequency-domain restriction conditions added has a larger normalized energy spectrum main lobe energy ratio. With increasing roll-off factor n, the energy ratio of the main energy spectrum of the normalized spectrum increases accordingly, i.e., the energy leakage is effectively suppressed. The baseband signal can be considered more suitable as a modern wireless communication system and can be obtained by adding a suitable restriction condition and establishing a model with a general function.

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