Rosdiadee Nordin

Recent Advances in Wireless Indoor Localization Techniques and System

The advances in localization based technologies and the increasing importance of ubiquitous computing and context-dependent information have led to a growing business interest in location-based applications and services. Today, most application requirements are locating or real-time tracking of physical belongings inside buildings accurately; thus, the demand for indoor localization services has become a key prerequisite in some markets. Moreover, indoor localization technologies address the inadequacy of global positioning system inside a closed environment, like buildings. Based on this, though, this paper aims to provide the reader with a review of the recent advances in wireless indoor localization techniques and system to deliver a better understanding of state-of-the-art technologies and motivate new research efforts in this promising field. For this purpose, existing wireless localization position system and location estimation schemes are reviewed, as we also compare the related techniques and systems along with a conclusion and future trends.

A Survey on Power Control Techniques in Femtocell Networks

Rapid increase in mobile data has raised the stakes on developing innovative new technologies and cellular topologies that can meet these demands in an energy efficient manner. One of the most interesting trends that will emerge from this cellular evolution is the femtocell networks. Femtocells are small, inexpensive, low power base stations that are generally consumer deployed, and are expected to significantly improve the coverage and capacity of the indoor users. Femtocell base stations (FBSs) have extensive auto configuration and self-optimization capability to enable simple plug-and-play deployment. The FBSs perform self-optimization function that continually adjusts the transmit power so the femtocell coverage does not leak into an outdoor area while sufficiently covering the indoor femtocell area. In this paper, different power control techniques in femtocell networks have been discussed and compared. The focus is on distributed power control techniques due to the decentralized nature of femtocell networks. The conclusion drawn from this review is that the distributed power control techniques using pilot power control schemes are simple and effective in optimizing the coverage of femtocells as well as reducing power consumption of the FBS. Furthermore a novel algorithm is still needed to perform power control optimization in femtocell networks. 

Survey of Green Radio Communications Networks: Techniques and Recent Advances

Energy efficiency in cellular networks has received significant attention from both academia and industry because of the importance of reducing the operational expenditures and maintaining the profitability of cellular networks, in addition to making these networks “greener.” Because the base station is the primary energy consumer in the network, efforts have been made to study base station energy consumption and to find ways to improve energy efficiency. In this paper, we present a brief review of the techniques that have been used recently to improve energy efficiency, such as energy-efficient power amplifier techniques, time-domain techniques, cell switching, management of the physical layer through multiple-input multiple-output (MIMO) management, heterogeneous network architectures based on Micro-Pico-Femtocells, cell zooming, and relay techniques. In addition, this paper discusses the advantages and disadvantages of each technique to contribute to a better understanding of each of the techniques and thereby offer clear insights to researchers about how to choose the best ways to reduce energy consumption in future green radio networks.

Accurate Wireless Sensor Localization Technique Based on Hybrid PSO-ANN Algorithm for Indoor and Outdoor Track Cycling

This paper aims to determine the distance between the mobile sensor node (i.e., bicycle) and the anchor node (i.e., coach) in outdoor and indoor environments. Two approaches were considered to estimate such a distance. The first approach was based on the traditional channel propagation model that used the log-normal shadowing model (LNSM), while the second approach was based on a proposed hybrid particle swarm optimization-artificial neural network (PSO-ANN) algorithm to improve the distance estimation accuracy of the mobile node. The first method estimated the distance according to the LNSM and the measured received signal strength indicator (RSSI) of the anchor node, which in turn used the ZigBee wireless protocol. The LNSM parameters were measured based on the RSSI measurements in both outdoor and indoor environments. A feed-forward neural network type and the Levenberg-Marquardt training algorithm were used to estimate the distance between the mobile node and the coach. The hybrid PSO-ANN algorithm significantly improved the distance estimation accuracy more than the traditional LNSM method without additional components. The hybrid PSO-ANN algorithm achieved a mean absolute error of 0.022 and 0.208 m for outdoor and indoor environments, respectively. The effect of anchor node density on localization accuracy was also investigated in the indoor environment.

Advanced handover techniques in LTE- Advanced system

There are always increasing demands of high speed data applications in wireless systems with fast and seamless access to voice and multimedia services and QoS guaranteed such as in Fourth Generation (4G) Long Term Evolution (LTE)-Advanced system. Moreover, as mobility speeds support is expected to reach up to 500 km/h, the handover will occur more frequent, thus the system performance in terms of delay and packet loss will be degraded. Hence, efficient radio resource management including handover techniques, load balancing and interference management are essential. In this paper, we present a comprehensive survey on the advanced handover techniques, requirements and features for LTE-Advanced system. Also, advanced handover techniques are highlighted and discussed such as Fractional Soft Handover (FSHO), Semi Soft Handover (SSHO) and multi-carrier handover (MCHO) that incorporate backward compatibility to the existing system. Meanwhile, FSHO technique based on CA with 5CCs are investigated in term of cell throughput and users handover numbers. The result shows that, FSHO with 5 CCs improves LTE-Advanced system in term of cell throughput and numbers of user handover better than Non-CA. Consequently, the existing handover techniques that have been proposed have several advantages, but they are not sufficient to solve hard handover problems. Therefore, a new handover technique is essential required to support fast and seamless handover in LTE-Advanced system. As a result, an advanced handover technique is proposed by combining FSHO, SSHO, and MCHO techniques that can enhance the system performance in term of latency, outage probability and handover reliability especially at cell boundary. Also, the expected output from this hybrid technique can reduce transmission overhead on the network cells by balancing the traffic load in the network cells.

Energy-efficient ZigBee-based wireless sensor network for track bicycle performance monitoring.

In a wireless sensor network (WSN), saving power is a vital requirement. In this paper, a simple point-to-point bike WSN was considered. The data of bike parameters, speed and cadence, were monitored and transmitted via a wireless communication based on the ZigBee protocol. Since the bike parameters are monitored and transmitted on every bike wheel rotation, this means the sensor node does not sleep for a long time, causing power consumption to rise. Therefore, a newly proposed algorithm, known as the Redundancy and Converged Data (RCD) algorithm, was implemented for this application to put the sensor node into sleep mode while maintaining the performance measurements. This is achieved by minimizing the data packets transmitted as much as possible and fusing the data of speed and cadence by utilizing the correlation measurements between them to minimize the number of sensor nodes in the network to one node, which results in reduced power consumption, cost, and size, in addition to simpler hardware implementation. Execution of the proposed RCD algorithm shows that this approach can reduce the current consumption to 1.69 mA, and save 95% of the sensor node energy. Also, the comparison results with different wireless standard technologies demonstrate minimal current consumption in the sensor node.

Evolution towards fifth generation (5G) wireless networks: Current trends and challenges in the deployment of millimetre wave, massive MIMO, and small cells

The exponential increase in mobile data traffic is considered to be a critical driver towards the new era, or 5G, of mobile wireless networks. 5G will require a paradigm shift that includes very high carrier frequency spectra with massive bandwidths, extreme base station densities, and unprecedented numbers of antennas to support the enormous increase in the volume of traffic. This paper discusses several design choices, features, and technical challenges that illustrate potential research topics and challenges for the future generation of mobile networks. This article does not provide a final solution but highlights the most promising lines of research from the recent literature in common directions for the 5G project. The potential physical layer technologies that are considered for future wireless communications include spatial multiplexing using massive multi-user multiple-input multiple-output (MIMO) techniques with millimetre-waves (mm-waves) in small cell geometries. These technologies are discussed in detail along with the areas for future research.

Classification, Recent Advances and Research Challenges in Energy Efficient Cellular Networks

There is a growing interest in improving the energy efficiency of communication networks to reduce operational expenditures, to maintain profitability and to make cellular networks greener. The revolution of green cellular networks has received significant attention from researchers, vendors, cellular service providers and governments, all of whom play important roles in the success of green networking technology. This paper aims to present a comprehensive overview on current green techniques for wireless networks, highlighting the energy savings that can be achieved by each technique, as well as the challenges faced by these techniques. Additionally, we present a summary of the essential research projects that have recently emerged for green mobile networks and display them as open research issues, thus providing researchers interested in pursuing this vision with the latest update.

Energy-Efficient Wireless Sensor Networks for Precision Agriculture: A Review

Wireless sensor networks (WSNs) can be used in agriculture to provide farmers with a large amount of information. Precision agriculture (PA) is a management strategy that employs information technology to improve quality and production. Utilizing wireless sensor technologies and management tools can lead to a highly effective, green agriculture. Based on PA management, the same routine to a crop regardless of site environments can be avoided. From several perspectives, field management can improve PA, including the provision of adequate nutrients for crops and the wastage of pesticides for the effective control of weeds, pests, and diseases. This review outlines the recent applications of WSNs in agriculture research as well as classifies and compares various wireless communication protocols, the taxonomy of energy-efficient and energy harvesting techniques for WSNs that can be used in agricultural monitoring systems, and comparison between early research works on agriculture-based WSNs. The challenges and limitations of WSNs in the agricultural domain are explored, and several power reduction and agricultural management techniques for long-term monitoring are highlighted. These approaches may also increase the number of opportunities for processing Internet of Things (IoT) data.

Vertical Handover Solutions Over LTE-Advanced Wireless Networks: An Overview

The convergence of multitude radio access networks forming a cluster of seamless heterogeneous wireless environment has made the wireless communication industry meet the paradigm of always best connected, where various mobile devices are able to access numerous types of applications and services. However, achieving such landmarks could not be possible without difficulties which this paper tries to highlight some of the technical challenges underlying seamless vertical handover. It provides a general overview of the mobility management process including a brief on multi-homing mobility protocol and focuses on vertical handover decision making techniques, hi ghlighting some radio interface standar and analysed some handover approaches. The paper proposes fast intelligent inter-layer network selection as a new handover approach to select the best network among the candidate networks, where Quality of Service, handover delay and improved data bit rates are set to be achieved.