QAM demodulation

1. A method of demodulating a signal on which is modulated, using a quadrature amplitude modulation scheme, a plurality of information symbols, the method including:

determining at least one QAM detection threshold corresponding to one or more of said information symbols; and

demodulating each information symbol on the basis of at least one respective QAM detection threshold,

wherein the information symbols modulated on the signal have a plurality data symbols arranged between a pair of successive pilot symbols, and

wherein at least one common QAM detection threshold is determined for a less than the number of symbols between said successive pilot symbols.

2. The method of claim 1 , wherein at least one common QAM detection threshold is determined in respect of individual information symbols.

3. The method of claim 1 wherein the QAM detection thresholds are determined by:

(a) determining an amplitude value in respect of a plurality of pilot symbols; and

(b) determining an amplitude value in respect of one or more information symbols between at least two of said pilot symbols on the basis of the amplitude values determined in step (a).

4. The method of claim 3 , wherein the amplitude value in respect of the information symbols between the pilot symbols by extrapolating or interpolating between the values determined in step (a).

5. The method of claim 1 , wherein the signal is an orthogonal frequency division multiplexing symbol.

6. An apparatus for demodulating a signal including a plurality of information symbols which are modulated using a quadrature amplitude modulation scheme, the apparatus including:

means for determining at least one QAM detection threshold corresponding to one or more of said information symbols; and

means for demodulating each information symbol on the basis of at least one respective QAM detection threshold,

wherein the information symbols modulated on the signal have a plurality data symbols arranged between a pair of successive pilot symbols, and

wherein at least one common QAM detection threshold is determined for a less than the number of symbols between said successive pilot symbols.

7. The apparatus of claim 6 which further includes channel estimation means configured to estimate a channel response of the signal; and means for equalizing the signal on the basis of the channel response determined by the channel estimation means.

8. A receiver adapted to receive a signal on which is modulated a plurality of information symbols using a quadrature amplitude modulation scheme, the receiver including an apparatus as claimed in claim 6 for demodulating the signal.

9. A receiver adapted to receive a signal on which is modulated a plurality of information symbols using a quadrature amplitude modulation scheme, the receiver including an apparatus as claimed in claim 7 for demodulating the signal.