Primitive Polynomials for Iterative Recursive Soft Sequential Acquisition of Concatenated Sequences

Abstract

An iterative initial sequence acquisition technique is proposed for the pseudo-noise signal derived from a pair of m-sequences used for generating the concatenated sequence, which relies on the soft-in-soft-out detection to improve the acquisition performance. This recursive soft sequential estimation technique has a linearly increasing complexity with the number of chips in the concatenated sequence. Receiving as few as S consecutive chips of a (2 S − 1)-chip sequence is sufficient for the local concatenatedsequence generator of the receiver to synchronize. Hence, this initial synchronization technique is eminently suitable for long m-sequences and concatenated sequences. Another key result is the comparison of m-sequences and concatenated sequences regarding the acquisition time. It is also observed that loworder primitive polynomials (PPs) achieve better performances than higher-order polynomials for both the m-sequences and concatenated sequences. When considering PPs having a higher number of taps, the exploitation of concatenated sequences is capable of achieving in excess of 3-dB signal-to-noise ratio gains over m-sequences.

Cooperative non-orthogonal multiple access for wireless communication networks by exploiting the EXIT chart analysis

“…EXIT charts have progressed as a tool to observe the convergence behavior of models by utilizing iterative decoding [34][35][36]. The signal to noise ratio (SNR) at which an extremely low bit error rate (BER) can be achieved for near-capacity performance is predicted by the use of EXIT charts without the need for Monte Carlo simulations [34,35].…”

“…8. The performances of matching the inner and outer curves depend upon the stair-shaped trajectory which is associated with the length of the interleaver which is always finite; therefore, the trajectory may not match perfectly to the inner and outer curves of the EXIT chart [34,36,37].…”

“…The signal mapper is used on encoded bit stream to transmit the information to the receiver, where the information is corrupted by noise. Thus, when receiving the N parallel decoder chains the MUD [34,36], is used to perform log likelihood ratio (LLR) on the concerned bits. On receiving the mth sub-carrier, the extrinsic LLR of the nth user's zth bit output from the MUD is evaluated as: where z of nth user's is obtained, having v ∈ {0, 1} and n ∈ 1, 2, .…”