Radio System Design for Telecommunications

Freeman, Roger L.

doi:10.1002/0470050446

Cited by 180 publications

(169 citation statements)

References 0 publications

Supporting

Mentioning

151

Contrasting

Unclassified

Order By: Relevance

“…Equation (1) is valid for radio frequencies up to 100 GHz with errors of less than 0.5% [9,10]. From Equation (1), we see that the radio refractivity consists of a dry and wet part [9][10][11][12]:…”

Section: Radio Refractivity and The Effective Earth Radius Factor (K-mentioning

confidence: 99%

Seasonal Distribution Modeling and Mapping of the Effective Earth Radius Factor for Microwave Link Design in South Africa

Nyete¹,

Afullo²

2013

PIER B

View full text Add to dashboard Cite

Abstract-In this paper we present seasonal results of the effective earth radius factor distribution in South Africa using recently (2007)(2008)(2009) acquired radiosonde data from the South African Weather Service (SAWS) for seven locations in South Africa. Two data modeling methods are used to formulate the solution for the distribution of the effective earth radius factor.The seasonal effective earth radius factor statistics obtained from the radiosonde measurements are then interpolated, gridded and presented in contour maps to cover the rest of the country for the four seasons defined by ITU-R recommendation P.453-10. The Integral of Square Error is used to check the performance of the data modeling techniques while the Root Mean Square Error is used to compare the performance of the different interpolation methods used.

show abstract

Section: Radio Refractivity and The Effective Earth Radius Factor (K-mentioning

confidence: 99%

Seasonal Distribution Modeling and Mapping of the Effective Earth Radius Factor for Microwave Link Design in South Africa

Nyete¹,

Afullo²

2013

PIER B

View full text Add to dashboard Cite

show abstract

“…These parameters are related to the atmospheric refractivity and can be expressed as in (4), where N is the atmospheric refractivity, n is the refractive index of the atmosphere, T is the temperature (K), P is the atmospheric pressure (hpa) and e is the water vapour pressure (hpa) [15,16]:…”

Section: Geoclimatic Factor Determinationmentioning

confidence: 99%

“…The water vapour pressure e is given by (5), where H (%) is the relative humidity and t ( • C) is the air temperature [15]: e = 6.1121H 100 exp 17.502t t + 240.97…”

Section: Geoclimatic Factor Determinationmentioning

confidence: 99%

Statistical Estimation of Fade Depth and Outage Probability Due to Multipath Propagation in Southern Africa

Asiyo¹,

Afullo²

2013

PIER B

View full text Add to dashboard Cite

Abstract-This study builds on the earlier work by Odedina and Afullo on Multipath fading in Durban. Their work was based on multipath measurements in Durban over a 6.73 km Line-of-Sight (LOS) link. This submission uses the geoclimatic factor approach and ITU-R recommendations P530-14 to obtain the multipath fading occurrence in five cities in South Africa, including Durban. Three-year radiosonde data is used in estimating the percentage of time that a certain fade depth is exceeded and hence outage probability due to atmospheric multipath propagation, assuming the given fade depth leads to the received signal falling below the squelch level. We employ the Inverse Distance Square technique to estimate point refractivity gradient not exceeded for 1% of the time in the lowest 65 m above the ground for five locations within South Africa. Standard error of the mean and confidence interval for both annual averages and seasonal averages of point refractivity gradient is calculated to reflect possible deviation in the given readings. These values of point refractivity gradient obtained are used in determining the geoclimatic factor K. The results presented show monthly, seasonal and annual variation of both point refractivity gradient and geoclimatic factor K. The results confirm that the geoclimatic factor K is region based. The percentage of time a given fade depth is exceeded for a single frequency increases rapidly with increasing path length. This is due to the fact that as the path length increases so do the multiple reflections leading to multipath propagation, which can result in either signal enhancement or multipath fading. A comparison of fade depth and outage probabilities is made with the earlier work in Durban and Rwanda in Central Africa.

show abstract

“…Fade depths can exceed 20 dB, particularly on longer LOS paths and more than 30 dB on longer troposcatter paths (Freeman, 2007;Grabner et al, 2011). Fade durations of up to several minutes or more can be expected.…”

Section: Introductionmentioning

confidence: 99%

Microwave propagation attenuation due to earths atmosphere at very high frequency (VHF) and ultra-high frequency (UHF) bands in Nsukka under a clear air condition

Ugwu¹,

Umeh²,

Ugonabo³

2015

Int. J. Phys. Sci.

View full text Add to dashboard Cite

The microwave propagation attenuation due to earth's atmosphere under a clear-air condition for fade depth of 10 dB was investigated using refractivity data calculated from weather vagaries measurement carried out between January and December 2008. The International Telecommunication UnionRadiocommunication Sector (ITU-R) model for multipath fading for small percentage of time with link distance of 100 km was used. The result showed that at this distance, the refractivity gradient has a strong correlation of 0.747 with percentage of time that the fade depth was exceeded. It was also observed that the percentage of time that the fade depth was exceeded increases with frequency until about 1.2GHz when the result becomes unreliable.

show abstract

Radio System Design for Telecommunications

Cited by 180 publications

References 0 publications

Seasonal Distribution Modeling and Mapping of the Effective Earth Radius Factor for Microwave Link Design in South Africa

Seasonal Distribution Modeling and Mapping of the Effective Earth Radius Factor for Microwave Link Design in South Africa

Statistical Estimation of Fade Depth and Outage Probability Due to Multipath Propagation in Southern Africa

Microwave propagation attenuation due to earths atmosphere at very high frequency (VHF) and ultra-high frequency (UHF) bands in Nsukka under a clear air condition

Contact Info

Product

Resources

About