Method and apparatus for selecting modulation and coding scheme (mcs) index based on frequency selectivity

A method of selecting a modulation and coding scheme (MCS) index from a predetermined MCS set, having same frequency efficiency, in a wireless communication system, the method comprising:

• measuring a signal to noise ratio (SNR) of a receiving signal;
• measuring a frequency selectivity of a receiving channel if a first MCS index is of the MCS set, wherein the first MCS index is determined by comparing the measured SNR against a prescribed SNR threshold;
• selecting a second MCS index having a coding rate below a predetermined coding rate threshold if the measured frequency selectivity is greater than or equal to a specified frequency selectivity threshold;
• and
• selecting the second MCS index having the coding rate greater than or equal to the predetermined coding rate threshold if the selected frequency selectivity is less than the specified frequency selectivity threshold,
• wherein the second MCS index is of the MCS set.

A method of selecting a modulation and coding scheme (MCS) index in a wireless communication system having a first MCS table associated with coding rate that is less than a specified coding rate threshold and a second MCS table associated with coding rate that is greater than or equal to the specified coding rate threshold, the method comprising:

• measuring a frequency selectivity of a receiving channel;
• selecting a MCS index from the first MCS table if the measured frequency selectivity is greater than or equal to a specified frequency selectivity threshold;
• and
• selecting the MCS index from the second MCS table if the measured frequency selectivity is less than the specified frequency selectivity threshold.

An apparatus for selecting a modulation and coding scheme (MCS) index in a wireless communication system, the apparatus comprising:

• a frequency selectivity measurement module configured to measure a frequency selectivity of a receiving channel;
• and
• a MCS index selection module configured to:
• select a MCS index having a coding rate below a prescribed coding rate threshold value if the measured frequency selectivity is greater than or equal to a specified frequency selectivity threshold, and
• select the MCS index having the coding rate above or equal to the prescribed coding rate threshold value if the measured frequency selectivity is less than the specified frequency selectivity threshold.