This work analyzes the performance of a cache-enabled vehicular communication network with platooned vehicular users aided by base stations (BSs) for cellular connectivity. We consider a caching scheme that prioritizes searching for files within the same platoon to minimize latency and resorts to the BS connection if the file is unavailable in the platoon. The file access probability representing the probability of the typical vehicular user acquiring a file from another vehicle in the same platoon or from a BS is presented. We also study the design of optimal caching placement that maximizes the total file access probability subject to memory constraints. Further, design insights are provided with the help of derived expressions and numerical results. Results indicate that based on the system parameters and relative link quality of vehicular and cellular links, it may be optimal to cache more popular files or may not be optimal to cache any file at all.

Electrochemical communication is a mechanism that enables intercellular interaction among bacteria within communities. Bacteria achieves synchronization and coordinates collective actions at the population level through the utilization of electrochemical signals. In this work, we investigate the response of bacterial biofilms to artificial potassium concentration stimulation. We introduce signal inputs at a specific location within the biofilm and observe their transmission to other regions, facilitated by intermediary cells that amplify and relay the signal. We analyze the output signals when biofilm regions are subjected to different input signal types and explore their impact on biofilm growth. Furthermore, we investigate how the temporal gap between input pulses influences output signal characteristics, demonstrating that an appropriate gap yields distinct and well-defined output signals. Our research sheds light on the potential of bacterial biofilms as communication nodes in electrochemical communication networks.

Molecular communication has emerged as a promising candidate to provide communication capability to nano-networks. In this paper, we model and analyze a molecular ad hoc network (MolAN) consisting of multiple molecular communication links in a 3D medium. The transmitter end of each link has individual data to communicate to the receiver. We first develop an analytical framework to model the MoIAN. In particular, we model the receivers as marked Poisson point process with transmit message as their marks. We then compute the mean signal strength, inter-symbol-interference and co-channel interference for degradable and non-degradable molecules. We derive the performance of the network in terms of the probability of successful bit detection. We also study the network throughput as a function of link active probability to show the existence of an optimal network density. Finally, we present some numerical results to derive interesting design insights.

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.

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.

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.