Long Term Evolution (LTE) is considered a 4G network technology. According to the GSMA, the trade group that promotes the GSM family of technologies, LTE is the next step from 3G/WCDMA & HSPA for many already on the GSM technology curve. Interestingly, though, a number of carriers across the world on the CDMA technology path have opted to switch to LTE for their 4G network upgrades. According to the GSMA, LTE is designed to be backwards-compatible with GSM and HSPA, and incorporates Multiple In Multiple Out (MIMO) technology in combination with Orthogonal Frequency Division Multiple Access (OFDMA) in the downlink and Single Carrier FDMA in the uplink to provide high levels of spectral efficiency. LTE can support channel bandwidths from 1.4 MHz to 20 MHz and both FDD and TDD operation. Commercial LTE service was first launched in December 2009 in Scandinavia by TeliaSonera. In 2010, carriers in the U.S. and Japan both released commercial LTE services. In the United States, MetroPCS offers LTE service in the AWS spectrum band, while Verizon Wireless offers LTE service in the 700 MHz spectrum band. Verizon said its LTE network, which it brands as a 4G service, provides average download speeds of 5-12 Mbps. AT&T Mobility is planning to launch LTE service in the United States in 2011, and Clearwire is testing LTE service in the TDD and FDD configurations. Sprint Nextel also is keeping open the possibility of launching LTE service. LTE-Advanced is the next step up in the evolution of LTE. According to the GSMA, LTE-Advanced “extends the technological principles behind LTE into a further step change in data rates. Incorporating higher order MIMO (4x4 and beyond) and allowing multiple carriers to be bonded together into a single stream, target peak data rates of 1 Gbps have been set.”