FIG. 1 is a block diagram illustrating a Radio Access Network (RAN) according to some embodiments of present inventive concepts. As shown, communications between base stations and one or more core network nodes (e.g., Mobility Management Entity MME or Service GPRS Support Node SGSN) may be provided using respective Si interfaces. Each base station BS may communicate over a radio interface (including uplinks and downlinks) with respective wireless terminals UEs in a respective cell or cells supported by the base station. By way of example, base station BS-1 is shown in communication with wireless terminals UE-1 and UE-2, base station BS-2 is shown in communication with wireless terminals UE-3 and UE-4, and base station BS-n is shown in communication with wireless terminals UE-5 and UE-6. Moreover, base station BS-1 may be a high-speed base station with a cell or cells supporting communication in a high-speed environment (e.g., along a high speed train track), base station BS-2 may be a normal-speed base station with a cell or cells supporting communications in a normal-speed environment (e.g., in an area with city traffic), and base station BS-3 may be a medium-speed base station with a cell or cells supporting communications in a medium-speed environment (e.g., along a highway).
