Positioning assistance data (PAD) is encoded in positioning System Information Blocks (posSIBs) and periodically broadcast by abase station in a differential manner A PAD element that is different relative to previously broadcast PAD is encoded in a block of posSIB separately from PAD that is unchanged. Another separate block of posSIB includes reference encoding identifying the changed PAD and provides scheduling information. A UE may decode the reference encoding and determine whether the UE has previously decoded the changed PAD. If the UE has previously received the PAD, but has not yet received the new or changed PAD, the UE may receive and decode the block of posSIB with only the changed PAD, thereby increasing efficiency.