PresentationPDF Available

Long Term Rain Attenuation Measurements for Millimeter Wave Short-range Fixed Links for 5G applications

Authors:

Abstract

Millimeter wave (mmWave) communication is a key technology for the fifth generation (5G) wireless communications and can be used for fronthaul, backhaul, and fixed link building to building transmission to provide high data transmission rate in indoor and outdoor environments. The electromagnetic wave above 10 GHz suffers more from rain attenuation, which causes the performance reduction and even outage of the communication system at mmWave bands for 5G fixed links. Therefore, rain attenuation effect on mmWave bands becomes an important issue and should not be neglected. The rain attenuation depends on the rain rate, rain drop size distribution (DSD), and complex water refractive index. Several works have been done to study the effect of precipitation on mmWave fixed links, and most of terrestrial link measurements are dedicated for long range and line of sight (LOS) links. The study needs a long term measurement over several years for accurate and useful results which should be qualified for a reliable radio link during precipitation events along the year. At Durham University, to study the rain attenuation on mmWave bands for 5G fixed link, a custom-designed continuous wave (CW) channel sounder is utilized to record channel data at K band (25.84 GHz) and E band (77.52 GHz) for direct and side fixed links with dual polarizations and a high performance PWS100 disdrometer is applied to collect weather data, including rain rate and rain DSD as shown in Fig.1 (a). The setup uses a transmitter (Tx) box shown in Fig.1 (b), a receiver (Rx) box for direct link (c), and receiver box for side link (d). The distance between the Tx and Rx is about 35 m for the direct link. The measurement setup conducts rain attenuation measurements and modeling for short-range building to building transmission scenario. Furthermore, the channel sounder has been updated based on the previous system [1], [2] in order to reduce the system attenuation loss, simplify the system, make it more stable than before, and also study the rain attenuation for both direct and side links simultaneously. Preliminary measurements after the update illustrate the impact of rain on the received signal strength shown in Fig.2. However, the side link has a larger variation due to multipath fading. The rain attenuations for direct and side fixed links are thoroughly compared for the two bands. The ITU-R P.838-3 model and DSD model are applied to rain attenuation modelling.
Long Term Rain Attenuation Measurements for Millimeter Wave Short-range Fixed
Links for 5G applications
Othman Zahid, Jie Huang, and Sana Salous
Department of Engineering, Durham University, Durham, DH1 3LE U.K.
Email: {othman.zahid, jie.huang, sana.salous}@durham.ac.uk
Millimeter wave (mmWave) communication is a key technology for the fifth generation (5G) wireless
communications and can be used for fronthaul, backhaul, and fixed link building to building transmission
to provide high data transmission rate in indoor and outdoor environments. The electromagnetic wave
above 10 GHz suffers more from rain attenuation, which causes the performance reduction and even
outage of the communication system at mmWave bands for 5G fixed links. Therefore, rain attenuation
effect on mmWave bands becomes an important issue and should not be neglected. The rain
attenuation depends on the rain rate, rain drop size distribution (DSD), and complex water refractive
index.
Several works have been done to study the effect of precipitation on mmWave fixed links, and
most of terrestrial link measurements are dedicated for long range and line of sight (LOS) links. The
study needs a long term measurement over several years for accurate and useful results which should
be qualified for a reliable radio link during precipitation events along the year.
At Durham University, to study the rain attenuation on mmWave bands for 5G fixed link, a custom-
designed continuous wave (CW) channel sounder is utilized to record channel data at K band (25.84
GHz) and E band (77.52 GHz) for direct and side fixed links with dual polarizations and a high
performance PWS100 disdrometer is applied to collect weather data, including rain rate and rain DSD
as shown in Fig.1 (a).
The setup uses a transmitter (Tx) box shown in Fig.1 (b), a receiver (Rx) box for direct link (c), and
receiver box for side link (d). The distance between the Tx and Rx is about 35 m for the direct link. The
measurement setup conducts rain attenuation measurements and modeling for short-range building to
building transmission scenario.
Furthermore, the channel sounder has been updated based on the previous
system [1], [2] in order to reduce the system attenuation loss, simplify the system, make it more stable
than before, and also study the rain attenuation for both direct and side links simultaneously. Preliminary
measurements after the update illustrate the impact of rain on the received signal strength shown in
Fig.2. However, the side link has a larger variation due to multipath fading. The rain attenuations for
direct and side fixed links are thoroughly compared for the two bands. The ITU-R P.838-3 model and
DSD model are applied to rain attenuation modelling.
References
[1] S. Salous, Y. Cao, and X. Raimundo, Impact of precipitation on millimetre wave fixed links,” in Proc.
EuCAP’19, Krakow, Poland, Apr. 2019, pp. 14.
[2] J. Huang, Y. Cao, X. Raimundo, A. Cheema, and S. Salous, Rain statistics investigation and rain
attenuation modeling for millimeter wave short-range fixed links,” IEEE Access, vol. 7, pp. 156110-
156120, 2019.
Figure 1. Fixed link experimental setup for rain
attenuation study.
(a) Weather
station
(b) Tx box
(c) Rx
direct link
(d) Rx
side link
Figure 2. The received signal against the rain
intensity on November 7, 2019.
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Millimeter wave (mmWave) communication is a key technology for fifth generation (5G) and beyond communication networks. However, the communication quality of the radio link can be largely affected by rain attenuation, which should be carefully taken into consideration when calculating the link budget. In this paper, we present results of weather data collected with a PWS100 disdrometer and mmWave channel measurements at 25.84 GHz (K band) and 77.52 GHz (E band) using a custom-designed channel sounder. The rain statistics, including rain intensity, rain events, and rain drop size distribution (DSD) are investigated for one year. The rain attenuation is predicted using the DSD model with Mie scattering and from the model in ITU-R P.838-3. The distance factor in ITU-R P.530-17 is found to be inappropriate for a short-range link. The wet antenna effect is investigated and additional protection of the antenna radomes is demonstrated to reduce the wet antenna effect on the measured attenuation.
Impact of precipitation on millimetre wave fixed links
  • S Salous
  • Y Cao
  • X Raimundo
S. Salous, Y. Cao, and X. Raimundo, "Impact of precipitation on millimetre wave fixed links," in Proc. EuCAP'19, Krakow, Poland, Apr. 2019, pp. 1-4.