QAM symbol mapping method and apparatus for downstream transmission of a cable modem
AssigneeElectronics and Telecommunications Research Institute
InventorsEun Jin, O Kwon, Soo Lee
Life of this patent
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Abstract
Provided is a QAM (Quadrature Amplitude Modulation) symbol mapping method and apparatus for downstream transmission of a cable modem. The method includes the steps of: determining phase information on the basis of predetermined relations between two bits representing set partitioning information and two LSBs (Least Significant Bits) of bits representing amplitude information, among bits input for QAM symbol mapping; separating I and Q signals of a first quadrant from the bits representing the amplitude information; and mapping the I and Q signals of the first quadrant to actual positions on the basis of the determined phase information.
Claims20
A QAM (Quadrature Amplitude Modulation) symbol mapping method, comprising the steps of:
- determining phase information on the basis of predetermined relations between two bits representing set partitioning information and two LSBs (Least Significant Bits) of bits representing amplitude information, among bits input for QAM symbol mapping;
- separating I and Q signals of a first quadrant from the bits representing the amplitude information;
- and
- mapping the I and Q signals of the first quadrant to actual positions on the basis of the determined phase information.
A QAM (Quadrature Amplitude Modulation) symbol mapping apparatus, comprising:
- a phase information extraction means for performing predetermined arithmetic operations between two bits representing set partitioning information and two LSBs (Least Significant Bits) of bits representing amplitude information, among bits input for QAM symbol mapping, to extract phase information;
- an I/Q signal separating means for separating I and Q signals of a first quadrant from the bits representing the amplitude information;
- and
- a mapping means for receiving the phase information from the phase information extraction unit, and mapping the separated I and Q signals of the first quadrant to actual positions on the basis of the received phase information.
Dependencies are inferred from the claim text.