LTE, LTE-Advanced and WiMAX: Towards IMT-Advanced Networks

Towards 4G Networks

Until very recently, the bulk of the international infrastructure for cellular networks was based on 2G networks. However, strong migrations to 3G networks occurred and are still underway, to CDMA based networks (3GPP and 3GPP2) and their respective evolutions. 3GPP standards ratified in 2006 and 2007 for High Speed Downlink and Uplink Packet Access (HSDPA and HSUPA), collectively called High Speed Packet Access (HSPA), have been ratified through several 3GPP Releases, with HSPA Evolution (HSPA+) ratified in 2007. Strong deployment activity followed shortly after, for example, US AT&T's HSDPA was launched in 2009, and T-Mobile announcing its HSPA+ in 2010 [4].

There is currently great activity in deploying the latter evolutions of 3G technologies, including both HSPA+ and LTE. The advent of the smart phones, such as Apple's iPhone and Android-based phones from various vendors [5]; in addition to other devices such as pads and 3G enabling USB connectors (dongles), are all accelerating such deployments. A boom in sales for smartphone devices can definitely be observed in the global market. Some earlier estimates had smartphone unit sales to be around 200 million units [4]. However, almost 300 million smartphone units were shipped last year, with overall handset shipments reaching 1.3 billion units. While iPhone assumes a greater market share, Android has undergone great growth in market share in 2010, with the remainder of the market shared by Nokia and Research ...