Systems, methods and apparatus select a code book based on channel conditions and performance of a demodulator or demapper in a wireless receiver. The method may include determining that the receiver in a first wireless communication apparatus is configured for iteratively processing signals received from a channel, selecting a code book for use in communicating over the channel based on conditions affecting transmission of the signals through the channel and performance information associated with a demapper in the receiver, and identifying the selected code book in one or more control channels transmitted to a second wireless communication apparatus.