Analysis of M-ary QAM-Based OFDM Systems in AWGN Channel

Author(s):  
Sarthak Pandey ◽  
Manisha Bharti ◽  
Ayush Kumar Agrawal
Keyword(s):  

To achieve a sen sational mistake adjusting capability, the 0.33 generation Partnership challenge (3GPP) prolonged haul improvement (LTE) makes use of speedy codes as its in advance blunder rectifying (FEC) modern day. moreover, to benefit better throughput, a LTE moreover executes numerous records various yield (MIMO) systems..no matter the way that a traditional rapid unwinding plan offers appealing execution within the best MIMO frameworks, significant execution degradation takes place in over-load MIMO frameworks at the same time as the amount of transmitting wires is greater outstanding than that of gathering mechanical assemblies. on this paper, a joint decoding plan for quicker codes, proposed with AWGN channel. In joint faster deciphering, calculations of sensitive statistics are driven for each combination of bits from all streams in place of freely among every circulate. to enroll within the trellis plots from each the streams, a incredible-trellis diagram is used. The numerical outcomes prepared through pc propagation show off that the proposed scheme offers tremendous execution over the usual affiliation in particular via distinct characteristic of an over-stacked MIMO frameworks. in the MIMO frameworks with 4 transmit and recipients, as much as as a minimum one.0 dB execution development can be gained at a bit mistake charge (BER) of . The proposed plot also accomplishes advanced throughput with a throughput/(SNR/flow into) quantity close to the theoretical furthest reaches of over-problem MIMO framework


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jiang Wu ◽  
Zhongpeng Wang

A data clipping and normalization technique is employed to improve the performance of the overall direct detection optical orthogonal frequency division multiplexing (DCO-OFDM) system. A detailed analysis of clipping distortion introduced by digital clipping and normalization is provided. The normalization operation amplifies the clipped data signal to the maximum input amplitude of a digital-to-analog converter (DAC). Based on the analysis, a BER formula of the proposed scheme is derived over the AWGN channel and single fiber channel. Performance of an optical clipped OFDM with normalization is assessed through numerical simulations and Monte Claro simulation over the AWGN channel. Theoretical analysis and simulation results both show that the clipping and normalization scheme can greatly improve the BER of an optical OFDM. In particular, BER performance of the proposed transmission scheme was measured in a practical OFDM transmission platform. The measured experimental results show that the clipped and amplified OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. The received sensitivity at a BER of 10−3 for a 4 Gsamples/s (2.6667 Gbits/s) clipped and normalized OFDM signal with clipping ratio of 4 after 100 km standard single-mode fiber (SMF) transmission was improved by 4.3 dB when compared with the conventional OFDM system. The measured results also showed that the clipped OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. Therefore, a clipping and normalization at the transmitter is most effective, and a substantial performance improvement can be obtained by a simple normalization after clipping.


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