  A novel SC decoding method of polar codes is proposed in $d$-deletion
channels, where a new pruning strategy is designed to reduce decoding
complexity. Considering the difference of the scenario weight distributions,
pruning thresholds for each node are designed separately according to a uniform
constraint on the pruning error probability, which further reduce the number of
scenarios that need to be calculated during the decoding procedure. In
addition, by exploiting the properties of the joint weight distribution, a
simplified calculation method of thresholds is proposed. Using this simplified
calculation method, the number of scenarios that required to be calculated is
reduced from $(d+1)(d+2)/2$ to $d+1$.
