Personal Digital Cellular (PDC) was a 2G

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standard used exclusively in Japan. After a peak of nearly 80 million subscribers to PDC, it had 46 million subscribers in December 2005, and was slowly phased out in favor of 3G technologies like

W-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the I ...

and

CDMA2000 CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and Signaling (telecommunication), signaling data between mobile phones and cell sites. It is developed by 3GP ...

. At the end of March 2012, the count had dwindled down to almost 200,000 subscribers. NTT Docomo shut down their network, mova, on April 1, 2012 at midnight.

Technical overview

Like D-AMPS and GSM, PDC uses TDMA. The standard was defined by the RCR (later became

ARIB The , commonly known as , is a standardization organization in Japan. ARIB is designated as the center of promotion of the efficient use of the radio spectrum and designated frequency change support agency. Its activities include those previously ...

) in April 1991, and NTT DoCoMo launched its Digital mova service in March 1993. PDC uses 25 kHz carrier, pi/4-

DQPSK Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at ...

modulation with 3-timeslot 11.2 kbit/s (full-rate) or 6-timeslot 5.6 kbit/s (half-rate) voice

codec A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or ...

s. 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,

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, and

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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 Speech coding is an application of data compression of digital audio signals containing speech. Speech coding uses speech-specific parameter estimation using audio signal processing techniques to model the speech signal, combined with generic ...

standard that was developed by

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 Algebraic code-excited linear prediction (ACELP) is a speech coding algorithm in which a limited set of pulses is distributed as excitation to a linear prediction filter. It is a linear predictive coding (LPC) algorithm that is based on the cod ...

6.7 kbit/s (a.k.a.

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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

standard that was developed by

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).ARIB RCR STD-27L, Personal Digital Cellular Telecommunication System RCR Standard
5.2 Half-rate speech CODEC

Operators of PDC service

* NTT DoCoMo (''mova'' brand): Service terminated on March 31, 2012 *

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(''SoftBank 6-2'' brand): Service terminated on March 31, 2010 *

KDDI () is a Japanese telecommunications operator formed on October 1, 2000 through the merger of DDI Corp. (Daini-Denden Inc.), KDD (Kokusai Denshin Denwa) Corp. (itself a former listed state-owned enterprise privatized in 1998), and IDO Corp. It h ...

** au: Service terminated on March 31, 2003 ** TU-KA: Service terminated on March 31, 2008

Standardization organizations

* Association of Radio Industries and Businesses (ARIB) * Telecommunication Technology Committee (TTC)

References

{{Mobile telecommunications standards Mobile telecommunications standards Japanese inventions