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In recent years, many researchers take great interest on visible light communication (VLC), due to its rich spectrum resources, no electromagnetic interference, good confidentiality, etc. In the visible light communication system, the information is loaded into the LED, then the light is transmitted in the free space, and the detector receives the signal. As the result of the −3dB modulation bandwidth...
To dynamically adjust the radio parameters is one of the basic capabilities of cognitive radio decision engine. This paper proposed a hill-climbing genetic algorithm which optimize optimal individual after one genetic iterative operation by hill-climbing algorithm. The proposed method would enhance the local search capability at the later stage of each generation of GA. We designed a multi-carrier...
Considering the potential interference of ultrawideband (UWB) on OFDM-based wireless communication systems, this paper studies coexistence issue between UWB with both impulse radio (IR) and multiband (MB) modulation and IEEE802.11n, WiMAX, and LTE downlink systems, using physical layer modeling strategy. According to the physical characteristics of UWB and the victim systems, entire physical layer...
The coexistence issues between UWB and WiMAX systems at 3.5GHz frequency band has been recently attached much attention. For investigating the potential interference of ultra-wideband (UWB) on a WiMAX system, an analysis method based on the physical layer modeling was presented. The physical layer models of impulse radio (IR) UWB, multi-band orthogonal frequency division multiplex (MB-OFDM) UWB and...
For these communication systems whose transmitted waveforms have a much closed signal space, such as the attractive Ultra Narrow-band (UNB) modulation technology, it is rather toilsome to obtain the satisfactory performance because of the difficulty in accurately determining the threshold of the optimum receiver, which is mainly caused by its tiny waveform dipartition as well as the unruly DC variant...
In this paper, a statistical analysis of the peak-to-average power ratio (PAPR) of Polynomial cancellation coded OFDM (PCC-OFDM) signals is presented. PCC-OFDM has the good performance of compressing intercarrier interference (ICI) at the cost of high PAPR. The most PAPR analysis assume the subcarriers to be identically and independently distributed (i.i.d). However, the correlation between adjacent...
A mathematical expression of side-band interferences caused by sub-carriers of multi-band (MB)-OFDM UWB based cognitive radio is derived. Based on this expression, the constraint relationship among transmitted symbols, which is satisfied to suppress the interferences, is obtained. Combined with this constraint, the design process of a type of LDPC-like modulation scheme is described. With modulation...
In order to decrease the signal length and transmitting time, improve accuracy of the delay time estimate, complete the mission of ranging and communication at the same time, a new ultra wideband (UWB) ranging method is developed in this paper. This method modulates the training sequence and information signals respectively on two carrier waves which are orthogonal mutually, and then combines them...
This paper proposes a low complex frequency domain channel estimation for ultra-wideband indoor environment. The channel parameters are the attenuations and delays incurred by the signal echoes along the propagation paths. Time-hopping (TH) modulation with binary symbols is assumed. Codewords span a transmission frame. Frames are separated by a guard time to cope with the channel time dispersion....
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