In all these early examples, a mobile phone had to stay within the coverage area serviced by one base station throughout the phone call, i.e. there was no continuity of service as the phones moved through several cell areas.
A cellular telephone switching plan was described by Fluhr and Nussbaum in 1973,[REF] and a cellular telephone data signaling system was described in 1977 by Hachenburg et al [REF].