Telecom and internet
D-VoiS Communications RF Engineer Interview: Rounds, Questions and Preparation
For RF Engineer roles at companies like D-VoiS Communications
What the job involves
An RF Engineer at a telecom and internet company plans, designs, and optimises radio frequency coverage for mobile networks (2G/3G/4G/5G) and fixed wireless or Wi-Fi links. Day to day work includes drive tests, RF surveys, link budget calculations, antenna configuration, interference analysis, and KPI monitoring to improve coverage, capacity, and call quality. Freshers often support field teams, analyse logs, and help tune parameters for sites in a region.
Role and Technical Knowledge
- 1
What is a link budget and why is it important for RF planning?
Explain that it accounts for transmit power, antenna gains, cable losses, path loss, and receiver sensitivity to ensure a reliable signal at the edge of a cell.
- 2
Explain the difference between RSSI, RSRP, and SINR in LTE.
RSSI is total received power including noise; RSRP is reference signal received power; SINR is signal to interference plus noise ratio, which directly affects throughput and modulation.
- 3
What is antenna downtilt and how does it affect coverage?
Downtilt is the vertical tilt of an antenna beam; electrical tilt is fixed, mechanical is adjustable. It controls cell size, reduces interference, and helps balance coverage and capacity.
- 4
What are the key KPIs you would monitor for a 4G site?
Mention RSRP, SINR, CQI, throughput (DL/UL), drop call rate, handover success rate, and accessibility (RRC setup success rate).
Practical Scenarios and Calculations
- 5
A site has good RSRP but poor SINR. What could be the cause and how would you fix it?
Likely interference or pilot pollution. Check for overshooting cells, adjust downtilt or azimuth, reduce power, or add a new site to improve dominance.
- 6
Calculate the free space path loss at 1800 MHz for a distance of 1 km.
Use FSPL (dB) = 32.44 + 20 log10(f in MHz) + 20 log10(d in km). For 1800 MHz and 1 km, it is about 97.5 dB. Show the formula and steps.
- 7
You see a coverage hole in a drive test plot. How do you address it?
Verify if it is a real hole or measurement artifact. Options: add a new site, adjust tilt/azimuth of nearby sites, increase power, or use a repeater or small cell.
- 8
What is a handover and what parameters would you tune to reduce handover failures?
Handover transfers a call between cells. Tune hysteresis, time-to-trigger, and cell individual offsets to avoid ping-pong and late handovers.
Tools, Technologies, and Standards
- 9
What is the difference between 4G LTE and 5G NR in terms of RF design?
5G NR uses wider bandwidths, higher frequency bands (including mmWave), beamforming, and massive MIMO, requiring more precise planning for coverage and beam management.
- 10
How would you use a drive test tool like TEMS or NEMO?
Collect logs of RSRP, SINR, and events while moving; post-process to identify weak coverage, interference, and handover issues; correlate with site configuration.
- 11
What is VSWR and why is it important at a cell site?
Voltage Standing Wave Ratio measures impedance mismatch; high VSWR means reflected power, reduced efficiency, and potential equipment damage. Should be below 1.5:1 typically.
- 12
What are the basic regulatory considerations for RF in India?
Mention TRAI and DoT guidelines on spectrum allocation, EMF radiation limits (ICNIRP), and site installation norms.
Behavioural and HR Questions
- 13
Are you comfortable with extensive field work and travel to remote sites?
Be honest and positive. Mention willingness to learn on the job and adapt to field conditions, as RF roles often require site visits and drive tests.
- 14
Describe a time you solved a technical problem under time pressure.
Use STAR format: situation, task, action, result. Focus on logical troubleshooting, teamwork, and a measurable outcome.
- 15
Why do you want to work in RF engineering, especially in a growing telecom company?
Show passion for wireless technology, mention desire to work on live networks, and highlight eagerness to contribute to coverage and quality improvements.
- 16
How do you keep your technical knowledge updated?
Mention following telecom forums, reading 3GPP summaries, online courses, and hands-on practice with tools or simulations.
Ready to try it for real?
Take a timed test or talk through a mock interview for this role, then see your scores.
This is practice material for RF Engineer roles, written with AI. It is not a list of questions D-VoiS Communications or any other company has asked.