 services, totally skipping 3G. MetroPCS also worked on upgrading existing CDMA subscribers to a less costly enhanced voice data optimized Rev-A network to enable faster speeds without needing a costly LTE handset upgrade for the same. In the meantime, T-Mobile USA was upgrading its 3G infrastructure to offer 1Mbp speeds with HSPA+ service. T-Mobile USA was also acquiring AWS spectrum to be able to deploy LTE with its own network overlay strategy. But it also acquired MetroPCS to consolidate and become a leading provider. AT&T also deployed LTE in a network overlay strategy, along with its HSPA+ services using 700MHz spectrum and also AWS spectrum. Interestingly, AT&T also operated a wide network of Wi-Fi hotspots. Sprint is the only U.S. operator that deployed LTE with a single RAN strategy to enable it to upgrade its existing 2G and 3G networks. Sprint plans to invest in this strategy to improve on coverage, capacity, and overall data speeds. Sprint plans to optimally use the 5MHz of paired FDD spectrum in 1900MHz and needs to make long-term plans for the investments needed and to secure financial planning with a buy in from SoftBank of Japan. Also Sprint strategically acquired Clearwire, with its 4G network having 160MHz bandwidth in the 2.5GHz spectrum, to deploy a TD-LTE network. Traffic Profiles and Other Evolution Challenges When the operators plan and deploy solutions, they make assumptions about the kind of traffic that different subscribers want, the services that subscribers will be using, the bit rates that will be desired, and the number of devices that will be accessing the network. Note For a more rigorous treatment of these, refer to Chapter 1: parameters to be taken into account when dimensioning the network. Such parameters are also used for dimensioning the network to ensure QoS for all the service users and different applications. However, it is easy to see that the telecom market dynamics keep changing all the time. We see changes in subscriber patterns, devices usage, and many other aspects.