A user equipment (UE) may improve capability parameter signaling and handling phase discontinuity according to an absence or presence of certain capability parameters within a capability message. In one aspect, when a power amplifier capability parameter is present within a capability message, this may be treated as if a phase discontinuity capability parameter is absent from the capability message. Alternatively, in another aspect, when a power amplifier capability parameter is absent within a capability message, this may be handled as if a phase discontinuity capability parameter is present within a capability message. Thus, for band combinations that include intra-band carrier aggregation with a single band, UE may include a power amplifier capability parameter or a phase discontinuity capability parameter. For all other band combinations, the UE may refrain from including the power amplifier capability parameter and may include a phase discontinuity capability parameter in the capability message.