arXiv subjects

Prakash Chaki

Publications and source records attributed to Prakash Chaki.

3 recordsLinked to original sources

arXiv2026

Precoded Non-Orthogonal Frequency Division Multiplexing with Subcarrier Index Modulation

In this paper, we propose a novel precoded non-orthogonal frequency division multiplexing (NOFDM) with subcarrier index modulation (SIM) to increase spectral efficiency for multicarrier systems. The proposed NOFDM-SIM scheme is constituted by a filterbank multicarrier system under reduced subcarrier spacing, where precoded index modulated symbols are mapped onto the subcarriers. The detrimental effects of inter-carrier interference (ICI) resulting from the non-orthogonality between subcarriers are efficiently mitigated with the aid of eigenvalue-decomposition-based precoding. Our simulation results demonstrate that the proposed precoded NOFDM-SIM system exhibits a similar peak-to-average power ratio to OFDM and OFDM-SIM counterparts while achieving the bit error ratio limit of zero-ICI OFDM.

eess.SP↗

arXiv2026

Power-Domain-Multiplexed Precoded Faster-Than-Nyquist Signaling for NOMA Downlink

In this paper, we propose a novel precoded faster-than-Nyquist (FTN) signaling scheme with power-domain-multiplexing in non-orthogonal multiple access (NOMA) downlink for tapping the joint benefits of high spectral efficiency and simultaneous multiuser connectivity. Non-orthogonality is introduced in both the symbol-interval (time) domain as well as in the multiple-access (power) domain to achieve a flexible resource allocation. Eigendecomposition of the FTN-specific intersymbol interference (ISI) matrix is used to achieve efficient cancellation of ISI, while successive interference cancellation is used to eliminate multiuser interference induced by NOMA. We derive the achievable analytical rate bound and demonstrate the numerical results of the bit error rate performance for the proposed scheme.

eess.SP↗

arXiv2012

Symbiotic Cognitive Relaying with mobile Secondary nodes in Cognitive Radio Networks

In a Symbiotic Cognitive Relaying (SCR) scenario, the Secondary users(SU) nodes can act as multihop relays to assist the communication between Primary User(PU) nodes in the case of a weak direct link. In return, the SU nodes are incentivised with the right to carry out SU-SU communication using licensed PU band for a fixed amount of time, referred to as the 'Time Incentive'. Existing work on SCR is constrained to a fixed ad-hoc SU network. In this paper, we introduce mobility in SCR by considering mobile SU nodes while keeping the PU nodes fixed. This paper uses a specific mobility pattern and routing strategy for the SU nodes to propose theoretical bounds on the throughput and delay of PU-PU transmission. We derive analytically the least throughput and maximum delay possible in our model.

cs.NI↗