Patent ID: 7295517

Claim:
A baseband processor for processing a plurality of baseband sample signals derived by demodulating data transmitted in the form of a packet sent over a data channel during a packet transmission in a multicarrier Orthogonal Frequency Division Multiplexing (OFDM) communication system having a plurality of subchannels, wherein each packet includes a preamble, a header, and a data payload, comprising: an analog-to-digital converter to convert the baseband sample signal into a digital baseband sample signal wherein the preamble includes a plurality of subchannel symbols; an energy measure/gain set module coupled to a variable gain unit for providing a variable gain control setting V AGC which is inversely proportional to a short-term average received signal power and not equal to 1; a preamble processing module coupled to the analog-to-digital converter to receive the digital baseband sample signal, the preamble processing module including a sub-channel gain estimation module coupled to receive the digital baseband sample signal to estimate the gain estimation (h i ) for each sub-channel; and a channel quality estimation module that generates a channel quality estimation metric (M) that is equivalent to the normalized geometric mean of the squared magnitudes of the gain estimation (h i ) of each of the plurality of subchannels carrying data such that, M = 1 v A ⁢ ⁢ G ⁢ ⁢ C ⁢ ( ∏ i = 1 s d ⁢ ⁢  h i  2 ) 1 s d = 1 v A ⁢ ⁢ G ⁢ ⁢ C ⁢ ( ∏ i = 1 s d ⁢ ⁢  h i  ) 2 s d where s d is the number of sub-channels having data.