Apparatus and methods are provided for efficient bandwidth adaptation for wideband carrier. In one novel aspect, the UE starts a BWP timer upon detecting one or more BWP timer starting triggering events, resets the BWP timer upon detecting BWP resetting triggering events, and switches to the default BWP upon expiration of the BWP timer. The BWP timer starting triggering events comprises decoding a command to switch away from the default BWP, the detection of end of DL data transmission in DRX mode. In another novel aspect, the UE only decodes the DCI indication for active BWP switching in the first three OFDM symbols of a subframe or a slot. In yet another novel aspect, when the SPS is configured for the serving cell for a UE with multiple BWPs, the SPS is configured for all the BWPs accordingly.