Wireless Tech + AI: Key Interview Questions You Should Know
1. Explain OFDM system briefly. OFDM is a digital modulation technique used in many modern wireless communication systems, including Wi-Fi (IEEE 802.11ax/be), LTE, and 5G. It efficiently transmits a high data stream over multiple closely spaced orthogonal subcarriers (low data stream). Subcarriers are spaced such that they don't interfere with each other, despite overlapping spectrally. This maximizes spectral efficiency. OFDM is resilient to multiparty fading and delay spread, due to its use of cyclic prefix (CP). 2. How is OFDM resilient to multipath fading and delay spread? In wireless channels, signals often reflect off objects like walls, furniture, or people, creating multiple delayed copies of the transmitted signal. This causes ISI (Delayed signals from previous symbols interfere with the current symbol) and frequency selective fading (Some frequencies experience more fading than others due to constructive/destructive interference). OFDM Solution: Use Cyclic Prefix (CP) If ...