calable IP-based flat architecture which eases the deployment of the network. Flexible spectrum allocations: Scalable, non-contiguous and dynamic channel (bandwidth) allocations. Support for bandwidth allocations of 1.25, 5, 10, and 20 MHz. Less power consumption which improves the battery life. 5.5 CDMA450 During the last few years CDMA2000 1X and EV-DO networks have been introduced at 450-470 MHz bands. CDMA450 offers wide area coverage, good indoor coverage and large capacity, and supports wireless high-speed packet data services. CDMA450 is essentially the same as CDMA @ 800 and CDMA @ 1900 MHz with respect to technology except that it replaces the RF modules in the BTS. However, each CDMA450 BTS covers a much wider area than GSM/UMTS counterparts and the sister CDMA2000 systems operating on traditional frequency bands. Theoretically, doubling the frequency quadruples the number of base stations required. Thus, if one CDMA450 BTS is required to cover a certain area than to cover the same area with CDMA1900, the operator would need 13 base stations. Thus, the decrease in the number of BTSs and associated civil works will shorten the deployment time and overall cost providing operators a good amount of savings. About 135 CDMA450 devices are available from 26 suppliers as of September 2009. These include 91 CDMA2000 1X, 18 EV-DO Rev. 0 and 26 Rev. A devices. In addition, there are four WorldMode phones available from two suppliers which support operations in both CDMA2000 and UMTS/HSPA worlds. As of December 2009, 112 commercial networks of CDMA450 are operational in 59 countries. A number of WLL (Wireless Local Loop) developing and emerging markets operators have also deployed CDMA450 [12]. 5.6 EV-DO Network Architecture EV-DO network architecture is very similar to the cdma2000 1X network architecture. The major difference is that EV-DO doesn't require MSCs since it doesn't support circuit switched voice service. Figure 5.10 shows the RAN (BTS and BSC) and Core Network elements of EV-DO systems. The key elemen