Deployment of LTE voice is will now well documented. How do Service Brokers play into this scenario?

The current view is that LTE deployments will likely be a great catalyst for IMS deployments, and will rely on the IMS architecture.  As such, the Service Broker will play a crucial role in allowing these LTE/IMS networks to leverage existing applications on the legacy PSTN networks.  The IM-SSF functionality can leveraged to extend applications (such as PrePaid from the GSM/CMDA networks) to new LTE customers.  It’s easy to envision offering an existing mobile subscriber an upgrade to LTE that uses the same prepaid application, and hence exact same user experience.