The art of computer programming, volume 2 (3rd ed.): seminumerical algorithms
The art of computer programming, volume 2 (3rd ed.): seminumerical algorithms
Error Control Coding, Second Edition
Error Control Coding, Second Edition
Design of fast-prunable S-random interleavers
IEEE Transactions on Wireless Communications
Interleaver pruning for construction of variable-length turbo codes
IEEE Transactions on Information Theory
A Fast Recursive Algorithm and Architecture for Pruned Bit-reversal Interleavers
Journal of Signal Processing Systems
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In this letter, the design of efficient parallel pruned channel and turbo interleavers for Ultra Mobile Broadband (UMB) physical layer standard [1] is addressed. Channel interleaving is based on a bit-reversal algorithm in which addresses are mapped from linear order into bit-reversed order. Turbo interleaving is based on filling a 2D array row by row, interleaving each row independently using a linear congruential sequence (LCS), bit-reversing the order of the rows, and then reading the interleaved addresses column by column. To accommodate for flexible codeword lengths L, interleaving is done using a mother interleaver of length M = 2n where n is the smallest integer such that L ≤ M, such that outlier interleaved addresses greater than L - 1 get pruned away. This pruning operation creates a serial bottleneck since the interleaved address of a linear address x is now a function of the interleaving operation as well as the number of pruned addresses up to x. A generic parallel lookahead pruned interleaving scheme that breaks this dependency is proposed. The efficiency of the proposed scheme is demonstrated in the context of both UMB interleavers. An iterative pruned bit-reversal algorithm that interleaves any address in O(log L) steps is presented. Moreover, an iterative pruned turbo interleaving algorithm based on LCSs that interleaves any address in O(log2 L) steps is presented.