Wireless operators are looking to increase their average revenue per user (ARPU) by offering enhanced data services, thus driving the need for higher bandwidth and consequently higher data rates. In addition, the need to offer the subscriber a rich user experience is transforming the underlying network architecture. Voice-centric technologies like narrowband 2G GSM, IS-95 systems have evolved to current-generation WCDMA-based HSDPA and HSUPA
systems supporting peak data rates up to 10 Mbps. For future 3GPP long-term evolution specifications, complex
signal processing techniques such as multiple-input multiple-output (MIMO), along with new radio technologies like
orthogonal frequency-division multiple access (OFDMA) and multicarrier Code Division Multiple Access (MC-CDMA), are considered key to achieving target throughputs in excess of 100 Mbps. Alternate OFDM-based band wireless systems such as WiMAX have similarly evolved, achieving transmission speeds in excess of 70Mbps.