Effect of urban-site and vegetation on channel capacity in higher altitude platform communication system

2009 ◽  
Vol 3 (4) ◽  
pp. 703 ◽  
Author(s):  
S.K. Agrawal ◽  
P. Garg
2019 ◽  
Vol 9 (18) ◽  
pp. 3724 ◽  
Author(s):  
Jiang ◽  
Zhao ◽  
Liu ◽  
Deng ◽  
Luo ◽  
...  

The improvement for hybrid radio frequency–free space optical (RF–FSO) communication system in wireless optical communications has acquired growing interests in recent years, but rarely improvement is based on hybrid modulation. Therefore, we conduct a research on end-to-end mixed RF–FSO system with the hybrid pulse position modulation–binary phase shift keying–subcarrier intensity modulation (PPM–BPSK–SIM) scheme. The RF link obeys Rayleigh distribution and the FSO link experiences Gamma–Gamma distribution. The average bit error rate (BER) for various PPM–BPSK–SIM schemes has been derived with consideration of atmospheric turbulence influence and pointing error condition. The outage probability and the average channel capacity of the system are discussed as well. Simulation results indicate that the pointing error aggravates the influence of atmospheric turbulence on the channel capacity, and the RF–FSO systematic performance is improved obviously while adopting PPM–BPSK–SIM under strong turbulence and severe pointing error conditions, especially, when the system average symbol length is greater than eight.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Bobby Barua ◽  
S. P. Majumder

AbstractWeather conditions are severely degraded the performance of FSO communication link. Atmospheric turbulence is one of the important weather conditions that degrade the performance even under clear sky condition. In this paper, we provide a noble analytical approach to evaluate the performance of STBC coded FDM FSO communication system with direct detection optical receiver under turbulent condition. Analysis is carried out to find the channel capacity of RF subcarrier modulation taking into consideration the effect of strong atmospheric turbulence which is modeled as gamma-gamma distribution and the probability density function of the conditional CNR, conditioned on a given turbulence-induced fading is derived considering equal gain receive diversity combining technique with direct detection optical receiver followed by RF synchronous demodulation. Results are evaluated numerically in terms of average CNR, BER and channel capacity for several system parameters like turbulence variance, link distance, data rate, etc.


Author(s):  
Banty Tiru

Power Line Communication (PLC) uses the available power line as a communication medium. The purpose of this chapter is to present the salient features, current trend and future scope of PLC with emphasis in the Indian context. Unlike other channels available, power lines are harsh media for data transfer and require efficient modeling and simulation techniques to propose and implement suitable mitigation schemes for achieving acceptable performance. Designed equipments have to adhere to strict mandates at the national and international levels to account for issues related to electromagnetic compatibility (EMC). In spite of this, PLC is expected to occupy an important place in the networking market in applications of smart grid and as a component of heterogeneous/hybrid communication system. The chapter is also backed by results from experiments carried on a typical power line in a test site with a presentation of noise, transfer characteristics, modeling and an estimate of the channel capacity.


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