Appendix D. Carrier-in-Carrier®

PERFORMANCE CHARACTERIZATION

D.1

Carrier-in-Carrier®Description

 

DoubleTalk™ Carrier-in-Carrier®(CnC) is an adaptive cancellation technology that

 

significantly reduces bandwidth occupancy by allowing two carriers to simultaneously

 

occupy the same spectral location, a practice that is disastrous for normal carriers. By

 

comparison, standard carriers must occupy non-overlapping spectral segments with no

 

more than one carrier in the same space.

 

In a number of ways, CnC carriers behave similar to conventional carriers in satellite

 

links. They are both exposed to adjacent carriers, cross-polarization and rain fade, and

 

exhibit impairments when any of these become too great. In addition, CnC operates in an

 

environment where:

 

• Carriers intentionally occupy the same spectral slot

 

• Performance depends upon desired and co-located interfering carrier.

 

Several areas relating to CnC performance are discussed, including:

 

Adjacent carrier performance

 

• Eb/No Degradation as a function of the CnC ratio

 

Symbol rate ratio

 

Carrier offset

• The effects of rain fade and asymmetric antennas.

D–1

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Mocomtech CDM-QX operation manual Performance Characterization, Carrier-in-CarrierDescription