User Equipment (700) reports single-cell or multi-cell channel state information to a base station (600) on a PUCCH Format 3 resource. The PF 3 resource selected depends on whether ACK/NACK needs to be reported simultaneously. Different coding and/or scrambling and/or Interleaving schemes are used depending on whether ACK/NACK bits are present, as well as the number of ACK/NACK and/or CSI bits. Resource compatibility is maintained independently of the details of coding, interleaving, or scrambling - that is, all formats can be orthogonally multiplexed onto the same time-frequency resources. The format used for CSI only is PUCCH Format 3c (PF 3c) whereas the PUCCH Format used for CSI and ACK/NACK is PUCCH Format 3b (PF 3b). PUCCH Formats 3b and 3c may be further differentiated depending on whether a CSI from a single or multiple cells are reported, or from which cells (PCell, SCeil) an ACK/NACK is reported. Ambiguity may be resolved by using different spreading codes for reference signals In PF 3b and 3c formats.