In a method of operating a communication network (20) a time division duplex (TDD) frame (F) of information is communicated over a radio interface (32) between a wireless terminal (30) and a base station node (28). The method comprises the wireless terminal (30) receiving plural downlink (DL) sub frames of the frame and, in response thereto, configuring a Physical Uplink Control Channel (PUCCH) channel to comprise up to four acknowledgements by using only two PUCCH channel resources and using PUCCH format Ia or PUCCH format Ib. In an example embodiment a PUCCH channel resource is specified by a sequence utilized for transmission of at least part of the PUCCH channel and a cyclical shift applied to the sequence. The two sequences of the respective two PUCCH resources are orthogonal, and the cyclical shift of the two PUCCH resources can be in a frequency domain, a time domain, or both the frequency domain and the time domain.