scholarly journals Spectral Efficiency Improving Technique in OCDMA-VLC system for IoT Application using Catenated-OFDM Modulation Scheme

2019 ◽  
Vol 557 ◽  
pp. 012036
Author(s):  
N. M. Nawawi ◽  
M. S. Anuar ◽  
M. N. Junita ◽  
M. F. Talib
Keyword(s):  
Spectral Efficiency ◽  
Modulation Scheme ◽  
Ofdm Modulation

scholarly journals Experimental evaluation of spectral efficiency from a circular array antenna producing a Laguerre–Gauss mode

2020 ◽  
Vol 7 (12) ◽  
pp. 201711
Author(s):  
Ben Allen ◽  
Timothy D. Drysdale ◽  
Chris Stevens
Keyword(s):  
Phase Shift ◽  
Antenna Array ◽  
Spectral Efficiency ◽  
Field Measurements ◽  
Modulation Scheme ◽  
Phase Shift Keying ◽  
Additional Degree ◽  
Shift Keying ◽  
Mode Purity ◽  
Circular Antenna Array

We present the four-dimensional volumetric electromagnetic field measurements ( x , y , z and frequency) of the complex radiated field produced by an 8-element circular antenna array. The array is designed to produce a Laguerre–Gauss (LG) mode l = +1 over the frequency range of 9–10 GHz. We evaluate our findings in terms of far-field LG mode purity and spectral efficiency in terms of the quadrature amplitude modulation (QAM) modulation scheme that can be supported. The application of LG modes in radio systems is as a means of multiplexing several data streams onto the same frequency, polarization and time slot, thus making a highly spectrally efficient transmission system or enhancing radar systems by means of exploiting mode behaviour as an additional degree of freedom. Our results show that for the circular antenna array, we find that mode purity is sufficient to support binary phase shift keying or quadrature phase shift keying modulation over a 0.3 GHz bandwidth, which corresponds to a spectral efficiency of 1.5 b s −1 Hz −1 per mode. Closer to the antennas' design frequency, 256QAM modulation may be supported over a 0.05 GHz band, and which corresponds to a spectral efficiency of 11 b s −1 Hz −1 per mode. We anticipate the practical insights provided in this paper contribute to the successful design of such systems.

scholarly journals Spatial Modulation for Beyond 5G Communications: Capacity Calculation and Link Adaptation

Proceedings ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 26 ◽  
Author(s):  
Anxo Tato ◽  
Carlos Mosquera
Keyword(s):  
Neural Network ◽  
Spectral Efficiency ◽  
Spatial Modulation ◽  
Modulation Scheme ◽  
Hardware Complexity ◽  
Simple Method ◽  
Communications Systems ◽  
Capacity Calculation ◽  
Good Trade ◽  
The One

Spatial Modulation (SM) is a candidate modulation scheme for beyond 5G communications systems due to its reduced hardware complexity and good trade-off between energy and spectral efficiency. This paper proposes two Machine Learning based solutions for easing the implementation of adaptive SM systems. On the one hand, a shallow neural network is shown to be an accurate and simple method for obtaining the capacity of SM. On the other hand, a deep neural network is proposed to select the coding rate in practical adaptive SM systems.

Digital outside-broadcasting-link using OFDM modulation scheme

1996 ◽  
Vol 42 (3) ◽  
pp. 266-271 ◽  
Author(s):  
S. Moriyama ◽  
K. Tsuchida ◽  
M. Sasaki ◽  
S. Yamazaki
Keyword(s):  
Modulation Scheme ◽  
Ofdm Modulation

scholarly journals Study on Predistortion Techniques and Adaptive Modulation Used in Fading Channels

2013 ◽  
Vol 756-759 ◽  
pp. 3723-3727
Author(s):  
Wei Liu ◽  
E Zhang
Keyword(s):  
Fading Channels ◽  
Spectral Efficiency ◽  
Adaptive System ◽  
Adaptive Modulation ◽  
Modulation Scheme ◽  
Primary Concern ◽  
Propagation Channel ◽  
Wireless Data ◽  
Mobile Channels ◽  
Linear And Nonlinear

Spectral efficiency is one of primary concern in the design of any wireless data communications systems, where fading is the main problem. An approach that can be taken to overcome the problem of fading is to adapt the modulation scheme according to the instantaneous propagation channel conditions. In this paper, we present a simplified mathematical model to calculate the probability of SER for any given constellation of M-QAM. This model plays an important role in designing spectrally efficient adaptive modulation over nonlinear mobile channels. Instantaneous spectral efficiency and its histogram distribution are found for linear and nonlinear channel cases. The achievable spectral efficiency is obtained for linear and nonlinear channel and compared with non-adaptive system and Shannon capacity.

Radio over Fibre Transport of Alamouti-coded MIMO Signals with Self-Recovery Capability

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Jaswinder Kaur ◽  
Vishal Sharma
Keyword(s):  
Spectral Efficiency ◽  
High Speed ◽  
Multipath Fading ◽  
Block Code ◽  
Wireless Channel ◽  
Modulation Scheme ◽  
Wireless Data ◽  
Wireless System ◽  
Radio Over Fibre ◽  
The Impact

AbstractRadio over Fibre (RoF) transport of high-speed wireless data provides a comprehensive solution for the forthcoming highly-reliable and spectral-efficient wireless systems. MIMO is one of the most widely used wireless technologies to increase the system reliability and capacity without any increased demand of power/bandwidth. However, the inherent non-linearities of RoF link and the multipath fading of the wireless channel can degrade the overall performance of the wireless system. In this work, authors demonstrate RoF transport of adaptively modulated MIMO signals and report the improvement in spectral efficiency under the impact of RoF link non-linearity. The transmitter of the proposed RoF based wireless system selects the appropriate modulation scheme with the assumption of perfect channel state information to achieve the acceptable BER at the subscriber end. The spectral efficiency improvement by this self-recovering MIMO-RoF system is evaluated by incorporating orthogonal Space-Time Block Code with 2 × 2 antenna configuration over the frequency-selective Rayleigh fading channel.

Tandem single sideband modulation scheme for doubling spectral efficiency of analogue fibre links

2000 ◽  
Vol 36 (13) ◽  
pp. 1135 ◽  
Author(s):  
A. Narasimha ◽  
X.J. Meng ◽  
M.C. Wu ◽  
E. Yablonovitch
Keyword(s):  
Spectral Efficiency ◽  
Modulation Scheme ◽  
Single Sideband ◽  
Single Sideband Modulation
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