xDSL (Digital
Subscriber Line) Physical Layer Modem Technologies
ETSI is very active in the
definition of physical layer standards for digital subsriber line
(DSL) technologies. It all started with the concept of Integrated
Services Digital Network (ISDN), and the so-called xDSL family has
continued to grow ever since, one success story after the other,
with the technologies such as HDSL, ADSL, VDSL and most recently
SDSL.ISDN, HDSL, ADSL, VDSL and SDSL are
all DSL modem technologies designed to operate on telephone wires
intended originally for voice-band communication (300Hz to 3.4kHz).
Advances in DSP technology combined with innovation in algorithms
and coding methods have allowed access to previously untapped
information capacity. Bandwidth utilisation has increased by two
orders of magnitude over the last ten years or so; from under 100kHz
for narrow-band ISDN to over 10MHz for VDSL
External Links
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Digital Subscribe Line-Wikipedia
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ADSL
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Carrierless Amplitude Phase (CAP) Modulation
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Dicsrete Multi Tone (DMT); Orthogonal Frequency Division
Multiplexing (OFDM)
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High Data Rate Digital Subscriber Line (HDSL)
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Very High Speed Digital Subscriber Line (VDSL)
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Symmetric Digital Subscriber Line (SDSL)
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Symmetric High Speed Digital Subscriber Line
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DSL Forum
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Technical Reports of DSL Forum
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