In some embodiments, a user equipment device (UE) implements improved communication methods which include radio resource time multiplexing, dynamic sub-frame allocation, and UE transmit duty cycle control. In some embodiments, the UE may communicate with base stations using radio frames that include multiple sub-frames, transmit information regarding allocation of a portion of the sub-frames of a respective radio frame for each of a plurality of the radio frames, and transmit and receive data using allocated sub-frames and not using unallocated sub-frames. In some embodiments, the UE may operate according to a sub-frame allocation based on its current power state. The UE may transmit information to the base station and receive the sub-frame allocation based on at least the information. In some embodiments, the UE may switch transmit duty cycles based on an occurrence of a condition at the UE. The UE may inform the network of the switch.