Abstract The conservation of ambient-sensitive pharmaceutical drugs is critical for maintaining their efficacy and safety, yet proper storage often becomes challenging once drugs reach patients’ homes. This paper presents a patient-centric drug quality conservation monitoring system that integrates IoT and blockchain technologies to address this gap. Sensor-equipped devices continuously track environmental parameters such as temperature, humidity, light, and movement, providing real-time alerts for any deviations that may compromise drug integrity. Patients are empowered to take corrective actions regarding conservation when necessary, while blockchain technology certifies their acknowledgment of non-consumable drugs, ensuring transparency and accountability. By leveraging cryptographic sensors and Ethereum-based smart contracts, the proposed platform offers an end-to-end solution to enhance patient engagement, ensure proper drug conservation, and support healthcare providers in remote monitoring. The protocol’s performance is evaluated in terms of cost, demonstrating its feasibility as an efficient and reliable solution for drug conservation monitoring.

Ambient-sensitive pharmaceutical products can be degraded if exposed to inappropriate temperature, humidity, light or movement conditions. Although most drugs are properly handled in hospitals, once they are dispensed to ambulatory patients, the prescribed environmental preserving conditions are not always met. The present work proposes a global design to support the proper drugs preservation once they are dispensed to the patient. The proposed solution consists of a monitoring network and a servers system. The former is composed by a sensor node attached to the medicament to collect the conservation parameters, and a gateway installed at the patients' home to periodically capture and analyze this data prior to forwarding them to the data server. The servers system processes this information to monitor, in real time, the drug conservation parameters. Whenever any preserving parameter is considered not acceptable, the system will automatically generate an alert to warn the patient and the hospital pharmacy practitioners. Moreover, blockchain technology is adopted to register key information, specifically to immutably record whenever an alert regarding the conservation conditions of the drugs is generated/deactivated. Furthermore, Elliptic Curve Cryptography signatures are introduced to verify the identity of gateways that originate the messages interchanged in the system. Finally, energy efficiency has been considered as a major issue in order to prolong the battery autonomy of the sensor nodes affixed to the dispensed drugs.

One of the key features that will bolster Wireless Body Area Networks (WBANs) widespread utilisation is the battery lifespan prolongation in the corporal sensors. The addition of energy harvesting methods in the sensors, and the use of energy efficient protocols in the WBANs, are essential to increase the battery duration. This work analyzes the effect of energy harvesting sensors in an ETSI SmartBAN PHY and MAC configuration framework already designed to lengthen the battery lifespan through reducing transceivers consumed energy. Analytical expressions for battery duration are derived. Computer simulation results substantiate the positive impact of energy harvesting on the battery lifespan, even for moderate captured power densities, when PHY and MAC layers are designed with energy efficiency in mind. Moreover, the obtained results demonstrate that the dependence of the battery lifetime elongation on the harvested power density is not linear and that higher harvestable power densities accentuate the batteries life lengthening.

This research work aims at analyzing the effects of using cooperative-ARQ (CARQ) in wireless relay systems employing AMC at the physical layer and an infinitely persistent type-I Hybrid FEC/CARQ protocol at the DLC layer. To that end, a cross-layer multidimensional discrete-time Markov chain (DTMC)-based queuing model is developed to jointly exploit the capabilities of CARQ and AMC. Based on the stationary state probability distribution of the proposed multidimensional DTMC, closed-form analytical expressions for performance metrics such as average throughput, queue length, packet delay and packet loss rate are derived, and the impact of cooperative relaying on these performance parameters is analyzed. Numerical results confirm the validity of the presented AMC/CARQ cross-layer analytical framework and reveal that the proposed CARQ protocol consistently outperforms the classical Type-I Hybrid FEC/ARQ schemes and provides a noticeable improvement when facing correlated fading channel scenarios.

A cross-layer performance analysis of a wireless network using adaptive modulation and coding at the physical layer and a truncated Chase combining hybrid automatic repeat request (HARQ-CC) scheme for error control at the data link layer is developed. Based on a Markov chain queueing model, analytical expressions for performance metrics such as throughput, average packet delay and packet loss rate are derived and then used to formulate a constrained optimization problem to maximize the system throughput under the prescribed Quality-of-Service constraints. Numerical results reveal that HARQ-CC consistently outperforms the classical Type-I Hybrid forward error correction/automatic repeat request schemes.

In this paper, a novel framework for the cross-layer design of wireless networks combining adaptive modulation and coding (AMC) at the physical layer with an automatic repeat request (ARQ) protocol at the data-link layer is proposed. In order to achieve this goal, the physical-layer service process is first modeled as a multidimensional finite-state Markov chain. Then, based on this multidimensional Markov model, the QoS performance at the data-link layer is characterized using the effective capacity approach. Queueing analysis using this effective capacity function is finally used in a cross-layer design approach aiming to satisfy the required average packet loss probability constraint by maximizing the average throughput of the system. Numerical examples are provided to show the advantages of our approach compared to other approaches using first-order amplitude-based finite state Markov models.

Nowadays, there are lots of research efforts focusing on cross-layer designs combining adaptive modulation and coding (AMC) with an automatic repeat request (ARQ) protocol. One of the main drawbacks of these research works is that they rely on first-order amplitude-based finite-state Markov chains (AFSMC) to model the wireless fading channel. Furthermore, most of the analytical models used in these works present several deficiencies that could compromise the design of cross-layer protocols. To overcome the aforementioned problems, in this paper we propose a novel cross-layer analytical framework that is based on both the use of a first-order two-dimensional Markov model and a judicious implementation of the AMC threshold searching algorithm used in the transmission mode (TM) selection. This threshold search is designed independently from the channel model and is able to discriminate between useful and useless TMs. To exploit the joint impact on QoS performance measures of both AMC and ARQ we present a formulation of an AMC/ARQ cross-layer design as a constrained optimization problem.

Group-orthogonal multicarrier code-division multiple access (GO-MC-CDMA) has been proposed as an attractive multiplexing technique for the uplink segment of wireless systems. More recently, a variant of this scheme has also been proposed for the downlink. This paper presents a unified bit error rate (BER) performance analysis of group-orthogonal wireless systems when using maximum likelihood (ML) multiuser/multisymbol detection covering both link directions. Valuable design rules regarding the number of subcarriers per group and the selection of spreading codes are derived. Simulations results using realistic system parameters and ETSI BRAN channel models are also presented which serve to validate the analytical results.

Group-orthogonal multicarrier code-division multiple access (GO-MC-CDMA) has been proposed as a multiplexing technique for the uplink segment of wireless systems. The distinctive feature of GO-MC-CDMA with respect to MC-CDMA is that users do not employ all the available subcarriers, instead, they are collected in orthogonal groups with each group functioning as an independent MC-CDMA system. When distributing users among groups, and in order to simplify network management and to increase system flexibility, it is important to allow users in the same group to employ different modulation formats and/or power constraints. This paper generalizes previous analyses of maximum likelihood (ML) multiuser detection (MUD) in GO-MC-CDMA to the case where, due to QoS requirements, users in the same group employ different modulation formats and/or receive different power levels. Simulations results using realistic parameters over an ETSI BRAN channel model are presented which serve to validate the analytical results.