Patent ID: 6850508

Claim:
A method for generating a block sequence number in a communication system for transmitting frames comprising the steps of: calculating a difference D between a first byte sequence number A of m bits and a second byte sequence number B of m bits, said first byte sequence number A indicating a first byte of transmission data, said second byte sequence number B indicating data of a first byte in a second block succeeding a first block to which the transmission data belongs, using the equation D={A−B+ 2 m } modulo 2 m ; and converting the first byte sequence number A to a block sequence number B_SEQ of n bits smaller in number than m bits using the difference D, using the equation B_SEQ={B(N R )+FLOORING(D,C)/C} modulo 2 n , where FLOORING(D, C) is a function for calculating a minimum value which is less than or equal to D and is a multiple of C, B(N R ) indicates a value determined by converting the second byte sequence number B of m bits to n bits, and C indicates a size of the frame; wherein each frame is comprised of a block sequence number and a succeeding data field which is filled with data bits having a byte length, the block sequence number being assigned to every block unit corresponding to a multiple of the byte to transmit the increased number of data bits, so that the data bits in at least one of the frames can be error checked in a byte unit at a receiving side.