Variable Spreading Factor Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM)

2002 ◽  
pp. 113-122 ◽  
Author(s):  
Hiroyuki Atarashi ◽  
Mamoru Sawahashi
Keyword(s):  
Spreading Factor ◽  
Code Division Multiplexing

Code Division Multiplexing Inspired Dynamic Metasurface Holography

2021 ◽  
pp. 2103326
Author(s):  
Xin Li ◽  
Ruizhe Zhao ◽  
Qunshuo Wei ◽  
Guangzhou Geng ◽  
Junjie Li ◽  
...  
Keyword(s):  
Code Division Multiplexing

scholarly journals M-ary nonlinear sine chirp spread spectrum for underwater acoustic communication based on virtual time-reversal mirror method

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Songzuo Liu ◽  
Habib Hussain Zuberi ◽  
Yi Lou ◽  
Muhmmad Bilal Farooq ◽  
Shahabuddin Shaikh ◽  
...  
Keyword(s):  
Acoustic Communication ◽  
Time Reversal ◽  
Spread Spectrum ◽  
Underwater Acoustic Communication ◽  
Half Cycle ◽  
Spreading Factor ◽  
Underwater Acoustic ◽  
Virtual Time ◽  
Chirp Spread Spectrum ◽  
Time Reversal Mirror

AbstractLinear chirp spread spectrum technique is widely used in underwater acoustic communication because of their resilience to high multipath and Doppler shift. Linear frequency modulated signal requires a high spreading factor to nearly reach orthogonality between two pairs of signals. On the other hand, nonlinear chirp spread spectrum signals can provide orthogonality at a low spreading factor. As a result, it improves spectral efficiency and is more insensitive to Doppler spread than the linear counterpart. To achieve a higher data rate, we propose two variants (half cycle sine and full cycle sine) of the M-ary nonlinear sine chirp spread spectrum technique based on virtual time-reversal mirror (VTRM). The proposed scheme uses different frequency bands to transmit chirp, and VTRM is used to improve the bit error rate due to high multipath. Its superior Doppler sensitivity makes it suitable for underwater acoustic communication. Furthermore, the proposed method uses a simple, low-power bank of matched filters; thus, it reduces the overall system complexity. Simulations are performed in different underwater acoustic channels to verify the robustness of the proposed scheme.

scholarly journals Isolation of human serum spreading factor.

1983 ◽  
Vol 258 (20) ◽  
pp. 12548-12552 ◽  
Author(s):  
D W Barnes ◽  
J Silnutzer
Keyword(s):  
Human Serum ◽  
Spreading Factor

Spatial code division multiplexing in optical data processing

2002 ◽  
Author(s):  
Zeev Zalevsky ◽  
David Mendlovic ◽  
Jonathan Solomon
Keyword(s):  
Data Processing ◽  
Spatial Code ◽  
Optical Data ◽  
Optical Data Processing ◽  
Code Division Multiplexing
Sign in / Sign up

Export Citation Format

Share Document