Unary-prefixed encoding of lengths of consecutive zeros in bit vector

A unary-prefixed encoding (UPE) algorithm for coding the lengths of zeros in a bit vector is proposed. While the lengths of consecutive zeros in a bit vector can be mapped to integer sources with a geometrical distribution (when the bits in the bit vector are independent of each other), the actual case, in a real-world situation, is more often that the distributions are exponential, with high peaks and heavier tails (when the bits in a bit vector are correlated). For the geometric distribution, the UPE code set can be proven to be optimal. For integer sources with high peaks and heavier tails, the UPE almost always provides better compression compared to existing suboptimal codes.