Further developments beyond third generation mobile communications

Second-generation mobile radio systems have been deployed world-wide. These systems are evolved to higher data rates and packet transmission. Third-generation mobile radio systems are currently being standardized worldwide to be initially deployed in 2001 and 2002 in different regions of the world. Advanced multimedia services are under development and first services are already being offered in second-generation systems. Already today the discussion is starting on the development of systems beyond third-generation mobile communications due to the long time frame for system specification and international standardization. This paper presents a concept for a system beyond third-generation mobile radio communications, which comprises a combination of several optimized access systems on a common IP-based medium access and core network platform. These different access systems will interwork by horizontal and vertical handover, service negotiation and global roaming. The different access systems are allocated to different cell layers with respect to cell size, coverage and mobility to provide globally optimized seamless services to users