  A coding scheme for two-page unrestricted-rate PRIO code that each page may
have different code rates is proposed. In the second page, the code for each
messages consists of two complementary codewords with code length n. There are
a total of 2n-1 codes which are disjoint to guarantees uniquely decodable for
2n-1 messages. In the first page, the code for each message consists of all
weight-u vectors with their non-zero elements restricted to (2u-1) same
positions, where non-negative integer u is less than or equal to half of code
length. Finding codes to be disjoint in first page is equivalent to
construction of constant-weight codes, and the numbers of disjoint codes are
the best-known numbers of codewords in constant-weight codes. Our coding scheme
is constructive, and the code length is arbitrary.The sum rates of our proposed
codes are higher than those of previous work.
