Adaptive Modulation (QPSK, QAM)

In this paper, introduced below are the concepts of digital modulation used in many communication systems today. Techniques described include quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) and how these techniques can be used to increase the capacity and speed of a wireless network. These modulation techniques are the basis of communications for systems like cable modems, DSL modems, CDMA, 3G, Wi-Fi* (IEEE 802.11) and WiMAX* (IEEE 802.16).