This document discusses 4G networks and Long Term Evolution (LTE). It explains that 4G uses programmable local oscillators and digital signal processing to implement different baseband processing algorithms for modulation and demodulation across different radio frequencies. It also examines the cyclic prefix and pulse shaping used in LTE, and describes the basic functions of an LTE receiver including fast Fourier transform, down conversion, channel correction, demapping, decoding and descrambling to extract the binary data from the received signal.