Like
D-AMPS and
GSM, PDC uses
TDMA. The standard was defined by the
RCR (later became
ARIB) in April 1991, and
NTT DoCoMo launched its Digital mova service in March 1993. PDC uses 25 kHz carrier, pi/4-
DQPSK modulation with 3-timeslot 11.2 kbit/s (full-rate) or 6-timeslot 5.6 kbit/s (half-rate) voice
codecs. PDC is implemented in the 800 MHz (downlink 810–888 MHz, uplink 893–958 MHz), and 1.5 GHz (downlink 1477–1501 MHz, uplink 1429–1453 MHz) bands. The air interface is defined in RCR STD-27 and the core network MAP by JJ-70.10.
NEC,
Motorola, and
Ericsson are the major network equipment manufacturers. The services include voice (full and half-rate), supplementary services (call waiting, voice mail, three-way calling, call forwarding, and so on), data service (up to 9.6 kbit/s
CSD), and packet-switched wireless data (up to 28.8 kbit/s
PDC-P). Voice codecs are
PDC-EFR and
PDC-HR. Compared to
GSM, PDC's weak broadcast strength allows small, portable phones with light batteries at the expense of substandard voice quality and problems maintaining the connection, particularly in enclosed spaces like elevators.
PDC-EFR PDC Enhanced Full Rate is a
speech coding standard that was developed by
ARIB in
Japan and used in PDC mobile networks in Japan. The carriers use one of those codecs as PDC-EFR:
CS-ACELP 8 kbit/s (a.k.a.
NTT DoCoMo Hypertalk) and
ACELP 6.7 kbit/s (a.k.a.
J-PHONE Crystal Voice). The PDC-EFR CS-ACELP uses
G.729. The PDC-EFR ACELP is compatible with the
AMR mode AMR_6.70.
PDC-HR PDC Half Rate is a
speech coding standard that was developed by
ARIB in
Japan and used in PDC mobile networks in Japan. It operates with a bit-rate of 3.45 kbit/s and is based on Pitch Synchronous Innovation
CELP (PSI-CELP). ==Operators of PDC service==