This book provides a detailed technical guide to the virtual and optimised roaming systems for mobile networks Written by a pioneer in the field, this book focuses on the implementation of virtual roaming systems. It generalizes the previous SS7 SMS interworking architectures to voice and data, GPRS, and 3G virtual roaming; extending the discussion of virtual roaming to include location based services, optimal routing and 4G perspectives. The author provides a thorough and detailed technical explanation of the topic covering subjects such as Over the Air (OTA) provisioning and detailed geo-localisation systems in a virtual roaming environment. Finally, this book addresses the application of MAP, CAMEL, TCAP, SCCP, and GTP. Key Features: *Provides a thorough and detailed technical coverage of virtual and optimised roaming systems for mobile networks *Explores the application of MAP, CAMEL, TCAP, SCCP, and GTP *Discusses previous SMS Hubs architecture used for SMS interworking and generalises to voice, data, and 3G virtual roaming *Includes material on pre-paid case with CAMEL parameter transformations, SMS, Supplementary Services and USSD implementation *Focuses on roaming hubs (including an, introduction to Sigtran configuration) and transparent networks of hubs This book will serve as an invaluable reference for network and networking engineers, handset developers, systems implementers, systems integrators, systems software engineers and programmers, wireless specialists and anybody else seeking a comprehensive and practical guide to the basics of virtual roaming systems.