Browsing by Author "Tanç, A. K."

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Open Access
LDPC codes for interference channels in the primary decodes cognitive regime
(Institute of Electrical and Electronics Engineers Inc., 2019) Shakiba-Herfeh, Mahdi; Tanç, A. K.; Duman, Tolga M.
We investigate cognitive interference channels (CICs), a variant of two-user ICs in which one of the transmitters (called the cognitive transmitter) has non-causal knowledge of the other's (private user's) message. Prompted by the information theoretical results, we design an explicit coding scheme for CIC in the primary decodes cognitive regime. We present a novel joint decoder and design low-density parity-check codes for this set-up. Simulation results demonstrate that the proposed joint decoder and the designed codes outperform the conventional maximum ratio combining type decoder and the point-to-point optimal codes, respectively.
Open Access
On LDPC codes for Gaussian interference channels
(IEEE, 2014) Sharifi, S.; Tanç, A. K.; Duman, Tolga M.
In this paper, we focus on the two-user Gaussian interference channel (GIC), and study the Han-Kobayashi (HK) coding/decoding strategy with the objective of designing low-density parity-check (LDPC) codes. A code optimization algorithm is proposed which adopts a random perturbation technique via tracking the average mutual information. The degree distribution optimization and convergence threshold computation are carried out for strong and weak interference channels, employing binary phase-shift keying (BPSK). Under strong interference, it is observed that optimized codes operate close to the capacity boundary. For the case of weak interference, it is shown that via the newly designed codes, a nontrivial rate pair is achievable, which is not attainable by single user codes with time-sharing. Performance of the designed LDPC codes are also studied for finite block lengths through simulations of specific codes picked from the optimized degree distributions.
Open Access
Short block length code design for interference channels
(IEEE, 2016) Sharifi, S.; Dabirnia, Mehdi; Tanç, A. K.; Duman, Tolga M.
We focus on short block length code design for Gaussian interference channels (GICs) using trellis-based codes. We employ two different decoding techniques at the receiver side, namely, joint maximum likelihood (JML) decoding and single user (SU) minimum distance decoding. For different interference levels (strong and weak) and decoding strategies, we derive error-rate bounds to evaluate the code performance. We utilize the derived bounds in code design and provide several numerical examples for both strong and weak interference cases. We show that under the JML decoding, the newly designed codes offer significant improvements over the alternatives of optimal point-to-point (P2P) trellis-based codes and off-the-shelf low density parity check (LDPC) codes with the same block lengths.
Open Access
Short block length trellis-based codes for interference channels
(Institution of Engineering and Technology, 2018) Dabirnia M.; Sharifi S.; Tanç, A. K.; Duman, Tolga M.
In this study, the authors consider Gaussian interference channels and fading interference channels, and design short block length codes based on trellis-based constructions. For both joint maximum likelihood (JML) decoding and single user minimum distance decoding, they obtain error-rate bounds to assess the code performance. Then they employ the obtained bounds for code design and present several design examples. For the case of quasi-static fading, they note that while the simple version of the derived bound is not sufficiently tight for code search purposes, one can obtain a tight performance bound with a higher complexity that can be used for a theoretical performance investigation. For the Gaussian case under JML decoding, they show that the newly designed codes provide significant improvements over point-to-point (P2P) trellis-based codes and off-the-shelf low density parity check codes. They also demonstrate that, for the case of independent and identically distributed fading, the best codes obtained by performing code search are P2P optimal ones, which is also verified by simulation results.