t of the same or better type or has similar or more capacity than the home network. The necessity is the IP-based backhaul while E1/TDM backhaul is not simply feasible for packet based technologies like EPS and WiMAX. The challenge comes in when handoffs takes place between EV-DO/HSPA to EPS or WiMAX where the former are typically backhauled via E1s. The E1 is not as adaptive as Ethernet systems and it will be difficult to maintain QoS or SLA (service level agreement) for data applications. 11.8.5 Device Attributes First and foremost the devices need to be capable of supporting multiple radio access technologies. In most cases, it is better to have dual antennas (mobile receive or mobile transmit diversity) in the devices to achieve a better data experience. At the same time it needs to be understood that the data experience will degrade once the user is moved from EPS or WiMAX to EV-DO or HSPA/HSPA+. It is also possible that EV-DO or HSPA networks have better data capabilities than the devices. For example, once a Mobile WiMAX user that is currently enjoying 4 Mbps data throughput on a WiMAX network hands-off to an EV-DO Rev. B network using a EV-DO Rev. A device. Although EV-DO Rev. B can support 4 Mbps the device can only go as high as 3.1 Mbps. 11.9 Fixed Mobile Convergence One of the major goals that the telecom industry is currently working to achieve is FMC. FMC (Fixed Mobile Convergence) is by no means an easy task; it involves almost all the players of both wireline and wireless worlds. FMC aims to enable converged services across the fixed, mobile and Internet environments but without a clear definition. FMC involves the convergence of three major components namely (Figure 11.13): Service Convergence Device Convergence Network Convergence. Network convergence is simply the enabler - the means by which network operators facilitate better access to value-added services and applications. In fact, the goal of network convergence is to make all services portable, profitable, and enable positive business mode