Adaptive channel characterization using decoded symbols

A method for channel interpolation in a receiver receiving a DQPSK modulated signal having offset periods of known receive symbols and periods of unknown receive symbols, the method comprising the steps of:

• maintaining a plurality of channel estimates corresponding to π/2 radian phase shifts during demodulation between a first group of known receive symbols and a second group of known receive symbols;
• and
• selecting one of the plurality of channel estimates to use for demodulating the signal between the first group and the second group of known receive symbols.

A system for characterizing propagation of a modulated signal received by a wireless device comprising:

• means for updating a propagation characterization at a first bandwidth responsive to an estimate generated from a first received signal corresponding to a decoded symbol and at a second bandwidth lower than the first bandwidth responsive to a second received signal corresponding to an undecoded symbol.

A system for channel interpolation in a receiver receiving a DQPSK modulated signal having offset periods of known receive symbols and periods of unknown receive symbols, the system comprising:

• means for maintaining a plurality of channel estimates corresponding to π/2 radian phase shifts during demodulation between a first group of known receive symbols and a second group of known receive symbols;
• and
• means for selecting one of the plurality of channel estimates to use for demodulating the signal between the first group and the second group of known receive symbols.