Cellular Digital Packet Data (CDPD)
Packet data overlay on AMPS
- connectionless (simpler than IS-95)
Requires dedicated equipment in each cell
- only shares spectrum, antennas & power
- limited coverage, high costs & prices
RF channel compatible with AMPS (30 KHz)
GMSK modulation @ 19.2 ks/s
- usable throughput less due to (63,47) RS FEC
Shared channel
- busy/idle bits for contention