Luby Transform Coding Aided Bit-Interleaved Coded Modulation for the Wireless Internet

Abstract

Abstract-Bit-Interleaved Coded Modulation using Iterative Decoding (BICM-ID) is amalgamated with Luby Transform (LT) coding. The resultant joint design of the physical and data link layer substantially improves the attainable Bit Error Rate (BER) performance. A Cyclic Redundancy Check (CRC) combined with a novel Log-Likelihood Ratio (LLR) based packet reliability estimation method is proposed for the sake of detecting and disposing of erroneous packets. Subsequently, bit-by-bit LT decoding is proposed, which facilitates a further BER improvement at a lower number of BICM-ID iterations. Finally, we revisit the pseudo random generator function used for designing the LT generator matrix.

Hybrid Automatic-Repeat-reQuest Systems for Cooperative Wireless Communications

“…However, when LT codes are employed for transmission over wireless channels, which impose both fading and inter-symbol interference, in addition to packet erasures, each LT codeword might become corrupted, which results in catastrophic inter-packet error propagation during LT decoding [182]. As illustrated in Fig.…”

“…As a result, more and more decoding errors appear, when the number of decoded packets increases. In order to mitigate the deleterious effects of error propagation, LT codes have been frequently combined with classic physical-layer FEC codes [182,183]. The idea of combining classic FEC codes with LT codes by directly amalgamating them was proposed in [40], where systematically concatenated parity bits were incorporated in order to create the family of SLT codes.…”

Amplify-forward and decode-forward cooperation relying on systematic Luby transform coded Hybrid Automatic-Repeat-reQuest

“…When employed for transmission over wireless channels, which impose both fading and intersymbol interference (ISI), the LT code might become contaminated, which results in catastrophic inter-packet error propagation during LT decoding [23]. In order to mitigate the deleterious effects of error propagation, LT codes have been frequently combined with classic physicallayer FEC codes [23,24].…”

“…When employed for transmission over wireless channels, which impose both fading and intersymbol interference (ISI), the LT code might become contaminated, which results in catastrophic inter-packet error propagation during LT decoding [23]. In order to mitigate the deleterious effects of error propagation, LT codes have been frequently combined with classic physicallayer FEC codes [23,24]. The idea of combining classic FEC codes with LT codes by directly amalgamating them was proposed in [6], where systematically concatenated parity bits were incorporated in order to create the family of SLT codes.…”

“…Hence, employing the RSD is not suitable for LT codes involving iterative soft decoding, especially when relying on simple parity check codes. To improve the achievable performance of both LT codes and SLT codes, the authors of [23,26] have proposed several improved distributions, namely the improved RSD (IRSD) distribution and the truncated degree (TD) distribution. The TD distribution has a low number of degree-one nodes and hence will be employed for designing the proposed systems.…”