In some embodiments, a user equipment (UE) and base station implement improved communication methods which enable a UE to operate according to a sub-frame allocation based on its current power state. The UE may transmit information including a maximum number of uplink (UL) sub-frames the UE can transmit in an allocation period and receive, from a base station, a first sub-frame allocation based on at least the first information. In embodiments, the UE may merge an un-allocated UL sub-frame's downlink association set with a next closest allocated UL sub-frame's downlink association set.