Narrow band PRACH with multiple tone hopping distances

摘要

Due to the limited dimension of a NB that may be used by multiple users, as well as possible large coverage areas, timing offset estimation may be outside of NCP. The inaccuracy in the timing estimate can be improved by using more than one tone hopping distance for PRACH. An apparatus may then transmit a first and second tone of the PRACH at a first hopping distance from the first tone. The apparatus may then transmit a third tone of the PRACH and a fourth tone of the PRACH at a second hopping distance from the third tone. The second hopping distance may be greater than first hopping distance. The apparatus may also transmit an additional tone of the PRACH using a random hopping distance. A receiving apparatus may receive the transmitted PRACH and determine a phase estimation based on the sets of tones having different hopping distances.