biology

Personal Digital Cellular

Personal Digital Cellular is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Personal Digital Cellular rather than just read about it. In short: Personal Digital Cellular (PDC) was a 2G mobile telecommunications 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 and CDMA2000.

Key takeaways

Personal Digital Cellular belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Personal Digital Cellular to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Personal Digital Cellular from memory before moving on to harder problems.

Reference excerpt

Personal Digital Cellular (PDC) was a 2G mobile telecommunications 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 and CDMA2000. 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) 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 NTT DoCoMo (mova brand): Service terminated on March 31, 2012 SoftBank Mobile (SoftBank 6-2 brand): Service terminated on March 31, 2010 KDDI 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)

See also AMR PDC-FR - VSELP-based old full-rate codec

References

Worked examples

Example 1 — a first encounter with Personal Digital Cellular

Start with the simplest possible case. Write down what Personal Digital Cellular claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Personal Digital Cellular before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Personal Digital Cellular ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Personal Digital Cellular

In research: Personal Digital Cellular appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Personal Digital Cellular in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Personal Digital Cellular is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2012 disestablishments in Japan, Japanese inventions, Mobile telecommunications standards, so understanding it makes those chapters shorter.
In everyday life: Look for Personal Digital Cellular outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Personal Digital Cellular in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Personal Digital Cellular means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Personal Digital Cellular out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Personal Digital Cellular in simple terms?

Why does Personal Digital Cellular matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Personal Digital Cellular?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Personal Digital Cellular.