Multi Carrier Modulation and Single Carrier Modulation

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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Fernando Ramirez-Mireles, [email protected], [email protected]

MultiCarrier vs

Single Carrier

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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MultiCarrier (Discrete Multi Tone DMT) and Single Carrier Modulation (SCM)

Signal PSD (dBm/Hz)

Frequency

(MHZ)

freq.1

freq.2

freq.3

freq.4

freq.5

US1 DS1 US2 DS2 US3

Signal PSD (dBm/Hz)

Frequency

(MHZ)

freq.1

freq.2

freq.3

freq.4

freq.5

US1 DS1 US2 DS2 US3

DISCRETE MULTI TONE (Divide and Conquer) SINGLE CARRIER MODULATION

Mr. FEC

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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Multicarrier (DMT) Processing

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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SCM Processing

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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Comparing Multicarrier (DMT) and SCM

Issues Deleterious effects

DMT solution SCM solution Advantages of DMT over SCM

Channel Time Dispersion

Signal Smearing

Equalization: Two simple equalizers, one in time domain and one in frequency domain

Equalization: One complicated equalizer in time domain

Simplicity in design and implementation

Frequency dependent Noise

Frequency dependent signal-to-noise ratio (SNR)

Bit loading: Transmit more bits in frequency bands where there is less noise and less bits in frequency bands where there is more noise

No bit loading: Transmit the same average number of bits in every frequency band regardless of amount of noise in each frequency band

Bandwidth efficiency and higher throughput

FDD full duplex operation in multi-band spectrum plans

Interference between upstream and downstream signals

Signal separation: Use no filtering, utilize Fourier Transform orthogonality properties

Signal separation: Use one complicated filter per transmission band

Higher spectrum utilization, higher throughput and flexible implementation of different band plans

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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FERNANDO RAMIREZ-MIRELES

[email protected]

Multi Carrier vs. Single Carrier Copyright 2012 Fernando

Ramirez-Mireles [email protected], [email protected]

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About the author

Fernando has over 10 years of experience in R&D in VDSL, UWB and speech processing. He has worked in the DSL field as a systems and algorithms engineer. He is currently a professor in the engineering division at ITAM in Mexico City. He has authored more than twenty technical articles and has one patent granted and two more pending. He is a senior member of the IEEE. He can be reached at [email protected].