Automated method for generating the cyclic redundancy check, or CRC, particularly for the transmission of multi-protocol packets in packet-switching networks

An automated method for generating the Cyclic Redundancy Check, or CRC, of a data packet, particularly for the transmission of packets recursively embedded in packet-switching networks, where a CRC is calculated by means of a linear feedback shift register, or LFSR, carrying out the calculation of a n-degree polynomial according to the following formula

• x[t0+1]=A·x[t0]+b·u[t0]
• where x is the LFSR state vector of size (n,1), and u is the incoming vector, for which
• x[t0+(i+1)·w]=Aw·x[t0+i·w]+Bw·uw[t0+i·w [1]
• where Aw is a (n,n) matrix and Bw is a (n,w) matrix, the CRC being calculated by means of the following formula
• CRC=x[t0+(k/w)·w]=x[p·w [2]
• at least one external CRC (C1 of FIG. 1) covering incoming binary data uw[t0}, uw[t0+1], uw[t0+2], . . . , u2[t0+h], . . . , uw[t0+h+c−1], . . . , uw[t0+p−1], of length k (where k=p·w, p being the number of w-bit data words), in which a data sequence uw[t0+h], . . . , uw[t0+h+c−1] (C2 of FIG. 1) is unknown until the instant (t0+k−1), the method being characterized by calculating the aforesaid external CRC (C1) via the following steps:
• calculation of a preliminary value V, equal to
• V=f(x[t0], uw[t0], uw[t0+1], . . . , uw[t0+h−1], 0[t0+h], . . . , 0[t0+h+c−1], uw[t0+h+c], . . . , uw[t0+p−1]) [1st term of [9]]
• calculation of a projection contribution PRJ, equal to
• PRJ(l, uw[t0+h], . . . , uw[t0+h+c−1]) [2nd term of [9]]
• sum of the preliminary value and of the projection contribution PRJ.