4G technologies like LTE and WiMAX aim to improve wireless services by providing better coverage, voice quality, data speeds, and revenue for operators. LTE employs OFDM and MIMO to achieve high spectrum efficiency and handle multipath fading, while WiMAX uses OFDM and is optimized for developing markets with limited wired infrastructure but available spectrum. Both technologies have strengths and weaknesses and may coexist, though LTE has broader device and network support currently from major mobile operators.