M. Shamim Kaiser

Power allocation in OFDM-based cognitive relay networks

This paper investigates power allocation in OFDM-based cognitive relay networks. Relay-assisted cognitive radio network (RCRN) combines diversity gain with spectral sharing technique and improves the spectrum utilization efficiency. A secondary user (SU) shares radio resources of a primary user (PU) under the condition that interferences from SU to PU is below a specific threshold. We formulate a power allocation optimization problem that maximizes the spectral efficiency of RCRN under total transmit-peak and total transmit-average interference power constrains. Numerical results show that RCRN provides significant performance improvement over single hop CRN (SCRN).

Energy-efficiency and reliability in MAC and routing protocols for underwater wireless sensor network

Underwater wireless sensor network (UWSN) technology has introduced a new flux to a whole gamut of application domains such as scientific exploration, commercial exploitation, underwater disaster prevention, etc. Such diversity of UWSN has gained prominence to the researchers quite fast and has marked this field of research as one of the emerging ones. With extensive researches conducted in this field, several design challenges have been experienced and explored by the network designers. Large propagation delay, low bandwidth, frequent loss of connectivity, variability of sound speed, limitation on source of energy, etc. are the key challenges, which are identified as necessary issues for establishing efficient and reliable UWSN. To address these issues, several MAC and routing protocols for UWSN have been proposed by the researchers during the last decade. In this review, the core design aspects for an ideal UWSN are identified which are energy-efficiency and reliability. These design aspects are evaluated in terms of energy consumption and communication efficiency - in order to provide an insight to the network designers on ideal design metrics. It is found that the protocols are highly selective, and the fitness of any protocol depends solely on the application and design requirements, which is addressed by this review. This paper also provides a comprehensive overview through comparison and simulation to analyze and summarize the MAC and routing protocols under concern.

A Neuro-Fuzzy Control System Based on Feature Extraction of Surface Electromyogram Signal for Solar-Powered Wheelchair

This paper presents the design and implementation of a low-cost solar-powered wheelchair for physically challenged people. The signals necessary to maneuver the wheelchair are acquired from different muscles of the hand using surface electromyography (sEMG) technique. The raw sEMG signals are collected from the upper limb muscles which are then processed, characterized, and classified to extract necessary features for the generation of control signals to be used for the automated movement of the wheelchair. An artificial neural network-based classifier is constructed to classify the patterns and features extracted from the raw sEMG signals. The classification accuracy of the extracted parameters from the sEMG signals is found to be relatively high in comparison with the existing methods. The extracted parameters used to generate control signals that are then fed into a microcomputer-based control system (MiCS). A solar-powered wheelchair prototype is developed, and the above MiCS is introduced to control its maneuver using the sEMG signals. The prototype is then thoroughly tested with sEMG signals from patients of different age groups. Also, the life cycle cost analysis of the proposed wheelchair revealed that it is financially feasible and cost-effective.

Radio Resource Allocation for Heterogeneous Services in Relay Enhanced OFDMA Systems

We propose a priority based resource allocation algorithm for heterogeneous services in the relay enhanced OFDMA downlink systems. The aim is to maximize the system throughput while satisfying the quality of service (QoS) requirements of heterogeneous services, comprising real time (RT) and non real time (NRT) services. The base station (BS) allocates resources dynamically to the users in a prioritized manner. The priority parameter depends on the channel condition, QoS requirement and data buffer information. We propose a suboptimal algorithm to reduce the computational complexity. The simulation results are compared with the fixed as well as dynamic resource allocation algorithms proposed in different researches. Our proposed scheme reduces the outage probability of the system and increases the system throughput.

Performance evaluation of a microcontroller-based solar powered auto-rickshaw

This paper represents the performance evaluation of a microcontroller based solar-powered auto-rickshaw which can be used extensively in Bangladesh for transportation. The battery operated traditional auto-rickshaw is charged by national grid whereas the battery bank of the proposed microcontroller based solar-powered auto-rickshaw is charged by solar power. A PIC microcontroller is programmed to control the duty cycle of the dc motor and thereby reduce the battery discharge time of the battery bank. The life cycle cost (LCC) analysis has been done and compared with the traditional battery operated autorickshaw. It has been found that LCC/kWh of the proposed rickshaw is minimum. The practical measured results reveal that the performance of the proposed rickshaw outperforms the conventional battery operated auto-rickshaw.

An intelligent flood monitoring system for Bangladesh using wireless sensor network

This paper presents a neuro-fuzzy controller based flood monitoring system using wireless sensor network. The distributed sensor nodes use IEEE 802.15.4 protocol, also called low rate wireless personal area network, to collect the sensor information such as water level data from the river, rainfall, wind speed and air pressure data from a selected site. In order to validate the proposed flood monitoring system, Chadpur, a flood prone district of Bangladesh, has been considered as selected site. The sensors information are sent to the distributed alert center via Arduino microcontroller and the XBee Transceivers. At the distributed alert center, XBee Transceiver and a Raspberry Pi microcomputer are used to generate flood alert based on sensor information and two decade flood data and these data are stored in a database. Sensor information are analyzed by the intelligent neuro-fuzzy controller used in Raspberry Pi microcomputer to announce the flood alerts. The wireless sensor network is connected as mesh topology which can send signals over far distance. The performance evaluation reveals that the proposed system accurately detect flood alert compared to the existing flood alert system.

Fuzzy logic based relay search algorithm for cooperative systems

Cooperative systems provide spatial diversity in wireless communications that is advantages when multiple antennas at wireless nodes are not cost effective. In this work, we propose fuzzy logic based relay search algorithm for 2- hop cooperative systems with the goal of maximizing the performance of a system in terms of SER (Symbol error rate). The algorithm requires effective SNR (signal to noise ratio), and total time delay of the link (propagation delay and processing delay at relay) as fuzzy parameters. The performance of the proposed algorithm is compared with BSelected Algorithm and Informed-Selected Algorithm. Simulation results shows that Fuzzy logic based relay search results in substantial improvement over the existing relay selection algorithms.

An Energy Conserving Routing Scheme for Wireless Body Sensor Nanonetwork Communication

Current developments in nanotechnology make electromagnetic communication possible at the nanoscale for applications involving body sensor networks (BSNs). This specialized branch of wireless sensor networks, drawing attention from diverse fields, such as engineering, medicine, biology, physics, and computer science, has emerged as an important research area contributing to medical treatment, social welfare, and sports. The concept is based on the interaction of integrated nanoscale machines by means of wireless communications. One key hurdle for advancing nanocommunications is the lack of an apposite networking protocol to address the upcoming needs of the nanonetworks. Recently, some key challenges have been identified, such as nanonodes with extreme energy constraints, limited computational capabilities, terahertz frequency bands with limited transmission range, and so on, in designing protocols for wireless nanosensor networks. This work proposes an improved performance scheme of nanocommunication over terahertz bands for wireless BSNs making it suitable for smart e-health applications. The scheme contains – a new energy-efficient forwarding routine for electromagnetic communication in wireless nanonetworks consisting of hybrid clusters with centralized scheduling; a model designed for channel behavior taking into account the aggregated impact of molecular absorption, spreading loss, and shadowing; and an energy model for energy harvesting and consumption. The outage probability is derived for both single and multilinks and extended to determine the outage capacity. The outage probability for a multilink is derived using a cooperative fusion technique at a predefined fusion node. Simulated using a nano-sim simulator, performance of the proposed model has been evaluated for energy efficiency, outage capacity, and outage probability. The results demonstrate the efficiency of the proposed scheme through maximized energy utilization in both single and multihop communications; multisensor fusion at the fusion node enhances the link quality of the transmission.

Low cost and portable patient monitoring system for e-Health services in Bangladesh

This paper proposes a low cost and portable patient monitoring system for e-Health services in Bangladesh. A raspberry pi microcomputer based system has been developed which can be used by paramedics for collecting different sensor data such as ECG signal, blood pressure signal, heart beat signal, Situation of Oxygen in Blood(SPO2), temperature and generating different signals from a patient and send these signals to specialist doctor who are in a centre or in a hospital. A web based application has been developed for both doctor and paramedics for efficient communicate with each other. It has been found that the system can be suitable for village health care centre of Bangladesh.

Outage capacity analysis of MC-CDMA based on cognitive radio network

Upcoming high data rate demand of wireless networks create radio frequency spectrum scarcity. This paper presents performance evaluation of cooperative relaying cognitive wireless network under Rayleigh fading channel. Our network scenario consists of a primary transmitter (PT) and primary receiver (PR) as well as a group of secondary transmitters (STs) and secondary receivers (SRs). Our network scenario also consists of a grouped STs into active and inactive. Only one active ST may transmit data at the same time slot using the licensed channel of PT If the transmit power of ST does not exceed predefined interference threshold. We also derived a closed-form expression for the outage capacity with the Rayleigh fading channel. The outage capacity analysis showed that numerical results are matched closely with simulation results.