bile went about their LTE deployments. NTT Docomo adopted the LTE network overlay strategy for its LTE services deployment in the 2.1 Ghz spectrum. KDDI also adopted the LTE network overlay strategy for its LTE services in the 800Mhz spectrum band. KDDI is also planning to deploy in 1.5Ghz spectrum for services covering urban and suburban areas. SoftBank Mobile also adopted the LTE network overlay for deployment of LTE services in the 2.1 Ghz spectrum in FDD mode to coexist along with its high-speed packet access-plus services in the 900Mhz spectrum. SoftBank Mobile also plans for LTE TDD deployment in the 2.5Ghz spectrum. Australia In Australia we looked at how Telstra and Optus went about their LTE deployments. Telstra opted for LTE network overlay strategy to ensure LTE service deployment did not affect its existing 2G and 3G network operations. Telstra targeted its existing 3G subscribers for the LTE services by offering dual-mode LTE/ HSPA+ dongles. Telstra deployed LTE on the 1.8Ghz spectrum and plans to selectively refarm the 900MHz too. The network operator Optus also used a network overlay strategy to introduce LTE services in refarmed 1.8GHz 2G spectrum. Optus acquired WiMax operator Vivid wireless to be able to deploy TD-LTE network with 98MHz bandwidth in the 2.3GHz spectrum. For the TD-LTE deployment Optus mostly needs to use a single RAN strategy. United States In the United States, we looked at network operators Verizon, MetroPCS, AT&T, and Sprint Nextel for their LTE deployment strategies. CHAPTER 3 DEPLOYMENT CHALLENGES IN EVOLVING 4G Verizon wireless used a network overlay strategy for deploying its LTE network, for a faster and less expensive deployment, along with its existing 2G and 3G services in the 1GHz spectrum. Verizon also plans for a 700MHz LTE deployment with 10MHz bandwidth. The operator continues to upgrade its subscribers to its LTE network with continuing growth and expansion plans. MetroPCS also used a network overlay strategy to deploy LTE services on top of its existing 2G CDMA