Method and apparatus for improving capacity in a radio communications system

A method of duplex communication over a wireless link between first and second terminals, comprising:

• transmitting from said first terminal to said second terminal over a first band of frequencies and transmitting from said second terminal to said first terminal over a second band of frequencies,
• transmitting feedback data from said first terminal to said second terminal in said first band of frequencies, said feedback data relating to the quality of communications received by said first terminal from said second terminal, and the transmission of said feedback data utilising a variable amount of the capacity of said first band of frequencies,
• determining an amount of available capacity in said first band of frequencies, using an amount of the capacity of said first band of frequencies for the transmission of said feedback data that is a function of the amount of capacity determined as being available in said first band of frequencies, and
• using said feedback data, if any, to improve transmissions from said second terminal to said first terminal in said second band of frequencies,
• the quality of communications from said second terminal to said first terminal being improved for a greater amount of the capacity of said first band of frequencies used by the transmission of said feedback data.