Digital Microwave Radio System in 18GHz Band: RSL Calculation

This assignment provides a detailed analysis of a digital microwave radio system operating in the 18GHz radio frequency band with a 2x2 Mbps transmission capacity, utilizing a passive repeater. It begins by calculating the nominal Receive Signal Level (RSL) at the receiver input under free space conditions, employing the link budget formula which considers transmitter power, branching and feeder losses, antenna gains, free space loss, and receiver losses. The calculation yields an RSL of -40.52 dBm. Furthermore, the assignment elucidates the purpose of passive repeaters in microwave transmission, highlighting their eco-friendliness and role in redirecting obstructed signals, leading to reduced maintenance and power costs, ultimately enhancing system performance. The document concludes with relevant references supporting the analysis and findings. Desklib offers this solution along with numerous others to aid students in their studies.

Running head: DIGITAL MICROWAVE RADIO SYSTEM 1
Digital Microwave Radio System
Name of Student
Institution Affiliation

DIGITAL MICROWAVE RADIO SYSTEM 2
Q1: The digital microwave radio system shown in Fig 1 below operates in the 18GHz radio
frequency band and provides 2x2 Mbps transmission capacity between two sites. The system
deploys a passive repeater.
Figure 1: Microwave Link Configuration
1. Calculate the nominal Receive Signal Level (RSL) at the input of the receiver in dBm
assuming free space conditions
Solution

DIGITAL MICROWAVE RADIO SYSTEM 3
In Unfaded conditions: the link budget is determined by the formula
PRX= PTX-LTX-FLTX+ATX-FSL+ARX-FLRX- LRX (Pahlavan & Krishnamurthy, 2011).
Where PRX= Unfaded Nominal Receiver Level in dBm
PTX = output of transmitter power in dBm
LTX =branching loses in the transmitter
FLTX = transmitter feeder loses of the waveguide or cable in dB
ATX = the antennae gains in dBi
FSL = the free space loses
ARX = the antenna gains in dBi
FLRX =receiver feeder loses of the waveguide or cable in dB
LRX =receiver branching loses
The provided parameters are
PTX = + 23 dBm
LTX = 3dB
FLTX = 1.5dB
ATX = 39.5dBi
FSL =?
ARX = 39.5 dBi
FLRX = 1.5dB
LRX = 4dB
Other Loses= 1dB
f = 18GHz= (18 * 10^9) Hz
D= (4.5 + 0.5) Km

DIGITAL MICROWAVE RADIO SYSTEM 4
= 5km
Determination of the FSL value.
FSL= ?
FSL= 20 log 10{¿)}
Where d= 5km
= 5 * 10^3
f= 18*10^9
c= 3*10^8
Substituting back to the equation
FSL= 20 log 10{¿)}
=20 log 10{¿)}
=20 log 10{4 π (3∗103)}
=20 log 10{3769911.184}
But log 10{3769911.184}= 6.57633
= 20 * 6.57633
= 131.52dB
Substituting:
PRX= PTX-LTX-FLTX+ATX-FSL+ARX-FLRX- LRX
= + 23 dBm - 3dB -1.5dB+39.5dBi -131.52Db+39.5 dBi-1.5dB -4dB- 1dB
= -40.52 dBm.
Q2: Purpose of passive repeaters in the microwave transmission

DIGITAL MICROWAVE RADIO SYSTEM 5
The passive repeaters are ecofriendly and will essentially act as beam blenders, which
implies that they redirect the signal which has been obstructed during the process of
transmission. The overall result is reduced maintenance costs, reduced power costs that enhances
the system performance (Parikh et al., 2010).

DIGITAL MICROWAVE RADIO SYSTEM 6
References
Pahlavan, K., & Krishnamurthy, P. (2011). Principles of wireless networks: A unified approach.
Prentice Hall PTR.
Parikh, P. P., Kanabar, M. G., & Sidhu, T. S. (2010, July). Opportunities and challenges of
wireless communication technologies for smart grid applications. In IEEE PES General
Meeting (pp. 1-7). IEEE.