Patent ID: 7702969

Claim:
A method executed on a computing device having a processor and memory, the method operating on a current S-random interleaver permutation (Π), stored in the memory and having a spread S, a size K, and that is collision-free, the method for generating for use in a turbo-decoder an expanded S-random interleaver permutation with an increased size, which is also collision-free, through an expansion technique which is carried out by the processor connected to said memory, the method comprising: iteratively adding to the current S-random interleaver permutation M terms or elements which satisfy the following relationship: ∀ i ∈ [ 0 ; K M - 1 ] , ∀ j , k ∈ [ 0 · M - 1 ] , with ⁢ ⁢ j ≠ k : ⁢ [ ∏ ( i + K M ⁢ j ) / ( K / M ) ] ≠ [ ∏ ( i + K M ⁢ k ) / ( K / M ) ] wherein i,j,k are indices which indicate the position of the M terms or elements in the current S-random interleaver permutation, said M terms or elements being added in respective positions i z such that: i z + 1 = ( i z + K M ) mod ⁢ ⁢ K , z = 0 , … ⁢ , K - 1 wherein the resultant expanded S-random interleaver permutation is used by a turbo-decoder in a communications device.