Nithin V Sabu
@msu.edu
Postdoctoral Research Associate
Michigan State University
RESEARCH, TEACHING, or OTHER INTERESTS
Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Nithin V. Sabu, Abhishek K. Gupta, Neeraj Varshney, and Anshuman Jindal
Institute of Electrical and Electronics Engineers (IEEE)
Molecular communication (MC) can enable the transfer of information between nanomachines using molecules as the information carrier. In MC systems, multiple receiver nanomachines often co-exist in the same communication channel to serve common or different purposes. However, the analytical channel model for a system with multiple fully absorbing receivers (FARs), which is significantly different from the single FAR system due to the mutual influence of FARs, does not exist in the literature. The analytical channel model is essential in analyzing systems with multiple FARs, including MIMO, SIMO, and cognitive molecular communication systems. In this work, we derive an analytical expression for the hitting probability of a molecule emitted from a point source on each FAR in a diffusion-based MC system with $N$ FARs. Using these expressions, we derive the channel model for a SIMO system with a single transmitter and multiple FARs arranged in a uniform circular array (UCA). We then analyze the communication performance of this SIMO system under different cooperative detection schemes and develop several interesting insights.
Abhishek K. Gupta and Nithin V. Sabu
IEEE
Molecular communication (MC) can enable nano-scale devices to communicate with each other using molecules as information carriers. To enhance the performance of MC, receiver-devices with multiple receiving ports can be utilized to form single-input multiple-output (SIMO) and multiple-input multiple-output (MIMO) communication links. The receiver ports are analogous to antennas in wireless communication. This paper considers a diffusion-based MC SIMO system with a point transmitter and one receiver system with many receiving ports (RxPs). We first characterize the joint channel between the transmitter and RxPs. We then present the optimal maximum-a-posteriori (MAP) decoding for this system when all ports can share complete information and a central device soft-combines the individual signal values to decode the signal. We then consider a Poisson channel approximation for the channel and show that weighted linear combining is an optimal decoding scheme with weights depending on average channel values. We also study a symmetric SIMO system and investigate the decoding error probability and diversity order for various soft and hard combining schemes.
Nithin V. Sabu, Abhishek K. Gupta, Neeraj Varshney, and Anshuman Jindal
IEEE
Nithin V. Sabu, Neeraj Varshney, and Abhishek K. Gupta
Institute of Electrical and Electronics Engineers (IEEE)
Molecular communication often involves coexisting links where certain links may have priority over others. In this work, we consider a system in three-dimensional (3-D) space with two coexisting communication links, each between a point transmitter and a spherical fully-absorbing receiver (FAR), where one link (termed primary) has priority over the second link (termed secondary). The system implements the underlay cognitive-communication strategy for the co-existence of both links, which use the same type of molecules for information transfer. The mutual influence of FARs existing in the same communication medium results in competition for capturing the information-carrying molecules. In this work, first, we derive an approximate hitting probability equation for a diffusion-limited molecular communication system with two spherical FARs of different sizes, considering the effect of molecular degradation. The derived equation is then used for the performance analysis of primary and secondary links in a cognitive molecular communication scenario. We show that the simple transmit control strategy at the secondary transmitter can improve the overall system’s performance. We study the influence of molecular degradation and decision threshold on the system performance. We also show that the parameters of the system need to be carefully set to improve the performance.
Abhishek K. Gupta, Nithin V. Sabu, and Harpreet S. Dhillon
Springer International Publishing
Nithin V. Sabu and Abhishek K. Gupta
Institute of Electrical and Electronics Engineers (IEEE)
In this letter, we consider a 3D molecular communication via diffusion system (MCvDS) with a single point transmitter and multiple fully-absorbing spherical receivers whose centers are distributed as a Poisson point process (PPP) in the medium. We derive the probability that a transmitted molecule hits any of the receivers within time $t $ . We consider both degradable and non-degradable molecules. We verify the analysis using particle-based simulation. The framework can be used for various applications, e.g., to derive event detection probability for systems where the IMs are transmitted to convey the occurrence of a particular event to trigger reactions at receivers or can be used as channel models for such systems.
Nithin V. Sabu, Neeraj Varshney, and Abhishek K. Gupta
Institute of Electrical and Electronics Engineers (IEEE)
Exact analytical channel models for molecular communication via diffusion (MCvD) systems involving multiple fully absorbing receivers (FARs) in a three-dimensional (3-D) medium are hard to obtain due to the mathematical intractability of corresponding diffusion equations. Therefore, this work considers an MCvD system with two spherical FARs in a 3-D diffusion-limited medium and develop several insights using an approximate analytical expression for the hitting probability of information molecule (IM). Further, based on the hitting probability, a novel approximate closed-form analytical expression for the area under the receiver operating characteristic curve (AUC) is derived to analyze the detection performance at each FAR in the presence of other FAR. Finally, simulation results are presented to validate the analytical results using the particle-based and Monte-Carlo simulations and to yield important insights into the MCvD system performance with two FARs.
Nithin V. Sabu and Abhishek K. Gupta
IEEE
Due to the limited capabilities of a single bionanomachine, complicated tasks can be performed only with the co-operation of multiple bio-nanomachines. In this work, we consider a diffusion-based molecular communication system with a transmitter bio-nanomachine (TBN) communicating with a fully-absorbing spherical receiver bio-nanomachine (RBN) in the presence of other TBNs. The bits transmitted by each of the TBNs are considered as random in each time slot and different for each TBNs contrary to the past works in literature with deterministic bits, which are the same to all TBNs. The TBNs are modeled using a marked Poisson point process (PPP) with the location of TBNs as points of PPP, and the transmit bits as marks. In this paper, we derive the expected number of molecules observed at the RBN and the bit error probability of the system. We validate our analysis using numerical results and provide various design insights about the system.
Nithin V. Sabu and Abhishek K. Gupta
Institute of Electrical and Electronics Engineers (IEEE)
In this paper, we present an analytical framework to derive the performance of a molecular communication system where a transmitter bio-nano-machine (TBN) is communicating with a fully-absorbing spherical receiver bio-nano-machine (RBN) in a diffusive propagation medium in the presence of other TBNs. We assume that transmit bits at each TBN is random and different than transmit bits at other TBNs. We model the TBNs using a marked Poisson point process (PPP) with their locations as points of PPP and transmit symbols as marks. We consider both inter-symbol interference (ISI) and co-channel interference (CCI). ISI is caused by molecules transmitted in the previous slots while CCI is due to the molecules emitted from other TBNs. We derive the bit error probability of this system by averaging over the distribution of the transmit bits as opposed to the past approaches consisting of conditioning on previous transmit bits and/or assuming the transmit bits of every TBN are the same. Using numerical results, we validate our analysis and provide various design insights about the system, for example, the impact of detection threshold on the system performance. We also show the importance of accurately incorporating the randomness of transmit bits in the analysis.
Nithin V. Sabu, Neeraj Varshney, and Abhishek K. Gupta
IEEE
Data transmission rate in molecular communication systems can be improved by using multiple transmitters and receivers. In molecular multiple-input multiple-output (MIMO) systems which use only single type of molecules, the performance at the destination is limited by inter-symbol interference (ISI), inter-link interference (ILI) and multi-user interference (MUI). This work proposes a new hybrid modulation for a system with multiple transmitters and receivers which uses different types of molecules to eliminate ILI. Further, to enhance the data rate of the proposed system under ISI and MUI, Mary CSK modulation scheme is used between each transmitter-receiver pair. In this paper, the random locations of transmitters present in the three dimensional (3-D) space are modeled as homogeneous Poisson point process (HPPP). Using stochastic geometry tools, analytical expression is derived for the probability of symbol error for the aforementioned scenario. Finally, the performance of the proposed system is compared using the different existing modulation schemes such as on-off keying (OOK), binary concentration shift keying (BCSK) and quadruple concentration shift keying (QCSK) to develop several important insights.