Transmitting data in a communication system

A method comprising:

• determining characteristics of a channel over which a signal is to be transmitted;
• encoding a first frequency portion of the signal using a first encoding method to produce a first encoded signal portion, the first frequency portion of the signal comprising a proportion of the signal that is calculated based on the determined characteristics of the channel, the calculated proportion being relatively higher when the determined characteristics of the channel indicate poor channel conditions than when the determined characteristics of the channel indicate good channel conditions, the first encoding method comprising a model based parametric encoding method;
• encoding a second frequency portion of the signal using a second encoding method to produce a second encoded signal portion, the second encoding method comprising a high quality non-model based encoding method, the second frequency portion of the channel comprising a remaining frequency portion of the channel that is not encoded by the first encoding method;
• and
• transmitting the first encoded signal portion and the second encoded signal portion via the channel.