A method for wireless communications is provided. The method includes transmitting a first signal during a first time interval. The first signal is encoded with a first spreading sequence generated by permutating a root sequence based on a permutation parameter associated with a first index. The method further includes transmitting a second signal during a second time interval. The second signal is encoded with a second spreading sequence generated by permutating the root sequence based on a permutation parameter associated with a second index. The method further includes receiving an indication of either the first index or the second index from a user equipment (UE).