Wireless Internet

Recent technological progress in microelectronics has allowed a considerable development of Wireless Sensor Networks. These networks are deployed in several relevant applications such as healthcare and wildlife which require the support of sensor nodes mobility. However, this mobility is a real threat in breaking communications and packet loss accordingly. This paper proposes a fast handover procedure based on a smart association decision to handle mobility and to ensure continuous communication in IEEE 802.15.4 WSNs. In our proposed procedure, the mobile node can anticipate the coordinator change upon detecting the degradation of the link quality indicator. Then, it performs a fast re-association based on our smart criterion and it resumes the forwarding of stored packets. Simulations show that our fast handover procedure ensures better network performances than a similar approach.

Wireless sensor networks will be responsible for the majority of the growth in smart building systems over the next decade. In resource constrained wireless sensor networks, it is very important to design the protocols with energy efficiency to prolong the lifetime of the sensor networks. Node clustering and data aggregation become popular since cluster-based sensor network can enhance the whole network throughput by aggregating the collected sensory information in each cluster. In such a network, the cluster head nodes play an important role in forwarding data originated from other common nodes to the sink. As a consequence, the cluster head nodes will have the problem of quick energy depletion upon multiple packets forwarding in high data load sensor networks. In this paper, we proposed a simple cluster-based linear network coding protocol in which random linear network coding is applied at cluster head nodes in order to minimize the number of forward packets to the sink. Simulation results are provided to show the efficacy of the proposed method in terms of the throughput and end-to-end delay.

Real-time monitoring applications may generate delay sensitive traffic that is expected to be delivered within a firm delay boundary in order to be useful. In this context, a previous work proposed an End-to-End Delay (EED) estimation mechanism for Wireless Sensor Networks (WSNs) to preview potential useless packets, and to early discard them in order to save processing and energy resources. Such estimation mechanism accounts delays using timers that make use of an Exponentially Weighted Moving Average (EWMA) function where the smoothing factor is a constant defined prior to the WSN deployment. Later experiments showed that, in order to enhance the estimation results, such smoothing factor should be defined as a function of the network load.

The current work proposes an optimization of the previous estimation mechanism that works by evaluating the network load and by adapting the smoothing factor of the EWMA function accordingly. Results show that this optimization leads to a more accurate EED estimation for different network loads.

Unfairness in wireless ad hoc networks is often due to the different ways the single nodes decide to participate in relay operations. We propose to introduce a dedicated ad hoc routing protocol based on results of game theory to force the cooperation of less operative nodes and mitigate the effort of overwhelmed ones. Simulations on an experimental testbed show a better distribution of the energy consumption and an increased fairness in the average delivery ratio achieved by nodes, as well as a prolonged network lifetime.

In this paper, we propose a more accurate model, than many existing models, to evaluate the throughput performance of the IEEE 802.11 distributed coordination function. The proposed model is based on a novel approach to modeling the backoff process where the average backoff window size is measured through information entropy estimation. Our approach provides a better description of the backoff process as compared to some of the models available in the literature. The behavior of the proposed model is validated via simulations and compared against that of some known models across a wide range of settings.

Traditional transport protocols have been designed to perform end-to-end transmission and retransmission. In terms of choosing the optimal transmission window, previous works suggest a value based on the bandwidth-delay product (BDP). For wireless networks, the BDP value is related to the round-trip hop length. However, there exists a new class of transport protocols that use intermediate caching which can drastically improve the performance even in the presence of high packet error rates. In this paper, we show that using a window size related to the BDP could lead to sub-optimal performance for caching-based protocols. Furthermore, we present a heuristic for choosing the optimal transmission window such that the optimal value is related to the average cache size in the intermediate nodes.

The classical energy detection (CED) system is a well-known technique for spectrum sensing in cognitive radio application. Generalized

$$p$$

-norm detector for spectrum sensing has been shown to provide improved performance over CED under certain conditions. Further, improved algorithm exists which works better than the classical energy detection algorithm. The present paper highlights the combined benefit of the

$$p$$

-norm detector and an improved algorithm for spectrum sensing in achieving a higher performance gain.

Advances in Internet of Things (IoT) technologies present enormous potential for the intensified healthcare support of senior or disabled citizens. Everyday objects will have the capability of directly interacting with each other and with humans. In this context we propose NCeH – a middleware solution that hides heterogeneity and offers a single common configuration and processing component for all nodes of IoT applications developed on top of it. The middleware is intended for the caring of people with special needs, such as video-vigilance, monitoring and so on, with multi-function, and is currently applied as a prototype in collaboration with cerebral palsy, blind and seniors caring institutions.

In this paper we present a survey of recent trends on short-term electricity-price prediction models. We classify the proposed price prediction methods based on the forecasting horizon into short- medium- and long-term approaches. We provide the key features of the medium- and long- solutions, while we emphasize on short-term prediction models, by providing their classification into statistical, computational intelligent and hybrid methods. We also highlight the key characteristics of the available prediction methods, while the strengths and weaknesses of these solutions are also discussed and analyzed. These important aspects should be considered by researchers that target on the derivation of more efficient and accurate electricity-price prediction models, especially for smart grid applications.

In this paper, the influence and improvement of the localization accuracy achieved using a fingerprint database with information coming from different channels and radio signal strength levels is evaluated. This study uses IEEE 802.15.4 networks with different power levels and carrier frequency channels in the 2.4 GHz band. Experimental results show that selecting part of this information with a cleverer data processing can provide similar or better localization accuracy than using the whole database.

Clustering has been recently suggested in VANETs to support privacy preserving systems and to provide LTE scalability. First, cluster formation has been suggested to share traffic using short range communication links, aggregate this traffic in one vehicle, and to relay this aggregated traffic hiding the transmitters identities. Second, teaming up vehicles into groups to aggregate traffic can also reduce the number of LTE uplink connections. In this framework, mobility-aware clustering techniques are fundamental to increase the lifetime of mobile clusters. In this paper we provide an insight on what is the achievable cluster lifetime when applying mobility-aware clustering to fast moving objects, and the penalties in terms of control overhead and convergence time. We provide simulation results in ns2 and compare these results with analytical results.

In wireless networks, mobile users connect either with other devices or with base stations. They can experience high errors caused by losses, low levels of signals or disconnections. Due to these aspects, it is important to find ways to make the communication reliable. Product network codes represent a way to improve error-correction capability. The main idea is to use a powerful error correction code in time with random linear network coding in space domain. This paper analyses the error-correcting capabilities of product network codes composed by either Luby transform (LT) codes or Reed-Solomon (RS) codes, and RLNC. The kind of errors are burst errors. The results quantify how product network codes improve reliability in case of high burst error probability.

The increasing threat of Denial of Service (DoS) attacks targeting Smart City systems impose unprecedented challenges in terms of service availability, especially against centralized control platforms due to their single point of failure issue. The European ARTEMIS co-funded project ACCUS (Adaptive Cooperative Control in Urban (sub) Systems) is focused on a centralized Integration and Coordination Platform (ICP) for urban subsystems to enable real-time collaborative applications across them and optimize their combined performance in Smart Cities. Hence, any outage of the ACCUS ICP, due to DoS attacks, can severely affect not only the interconnected subsystems but also the citizens. Consequently, it is of utmost importance for ACCUS ICP to be protected with the appropriate defense mechanisms against these attacks. Towards this direction, the measurement of the performance degradation of the attacked ICP server can be used for the selection of the most appropriate defense mechanisms. However, the suitable metrics are required to be defined. Therefore, this paper models and analyzes the impact of DoS attacks on the queue management temporal performance of the ACCUS ICP server in terms of system delay by using queueing theory.

Demand-Side Management (DSM) is an effective means to optimize resource utilization in the electricity grid. It makes the electricity consumption pattern of users more even, reducing the Peak-to-Average demand Ratio (PAR) in the power system. The utility company can monitor and shape the hourly electricity consumption of the users by adopting an appropriate pricing strategy and advertising it online exploiting the underlying Smart Grid infrastructure. On the other hand, the users can monitor the hourly price of electricity in the market and based on the price variation, they can schedule their appliances to minimize their electricity payment, without compromising their daily need. In this paper, we consider a DSM problem where the company adopts a quadratic pricing strategy to encourage the users to have a flat consumption pattern. We formulate the problem incorporating Quadratic Programming (QP). The simulation results show that the QP approach reduces the PAR drastically.

The electronic passport, introduced not long ago, in 2005, is continuing to evolve in order to provide higher levels of authentication for citizens crossing international borders, while respecting their privacy. A brief overview of the whole e-passport architecture is presented, as well as the key aspects and changes that this document has been going through in its evolution. In this paper we present a promising novel PKI-based security solution that could be integrated in the next generation (4G) of electronic passports, namely in its supporting overall architecture, in the ambit of the NewP@ss project.

The paper presents the advantage of the Ultra-thin body and buried-oxide (BOX) (UTTB) fully depleted silicon-on-insulator (FDSOI) as an enabling transistor technology through effective back-gate biasing schemes to overcome the challenges that arises from downscaling bulk CMOS technology for low power and high-speed design tradeoff. The effects of the back-gate bias methodologies that can vary or modulate the substrate bias to adapt the transistor’s threshold voltage are detailed. The design schemes that can be used with this technology are described to illustrate their applications with UTTB FDSOI transistor.

This paper proposes a scenario of service-oriented architecture based on OSGi technology, in combination with multi agents systems developed using JADE environment. A key part of the scenario is the new architecture for SIP application server as part of the IMS Core network. As a proof of concept, a simulated environment for a televoting service was implemented. The major contributions of this work are the identification and analysis of jitter, variation of jitter, packet loss, load capacity and CPU utilization of the JADE/OSGi SIP-AS. Test results validate the approach and show good overall performance.

This work intends to provide an assistive technology that helps blind persons to independently navigate inside public spaces. Blind persons often travel through known routes as they already know some features of it. Our technology helps users to travel through unknown spaces and find products or services available there. It is supported by personal smartphones running Android OS and beacons deployed in the space.

The tremendous growth of the transportation systems during the last decades has created a significant environmental impact. As a result, in order to reduce the atmospheric pollution many attempts have been employed, including eco-driving systems. However, the scope of such systems is only to attempt to inform the user about his driving behaviour. In the current paper, a novel system targeted for supporting green daily commuting habits, with a particular focus on helping the user save on fuel expenses and time on a regular daily basis is proposed and its functional architecture is fully presented.

The increasing proliferation of 4G mobile technologies is expected to satisfy the constantly growing demand for wireless broadband services. However, the high data rates provided by 4G networks at the air interface raise the need for more efficient management of the backhaul resources especially if the backhaul network has been leased by the mobile operator. In the present work, the authors investigate on the backhaul resource allocation problem at the side of the base station (BS) and a novel distributed scheme is proposed that can efficiently forecast the aggregated traffic demand at the BS using artificial neural networks. It is shown that the proposed scheme provides a mean absolute percentage error of about 10 % for the downlink traffic and about 19 % for the uplink traffic.

The number of standards and recommendations in IT grows. The requirements on applying them are of growing strength and frequency. Application of the standards is felt as a good solution. We show that if there are too many standards to apply or if they are too big, they can be sources of issues. We also discuss some of such issues like document size and error proneness.

Erasure codes have been employed in a wide range of applications to increase content availability, improve channel reliability, or to reduce downloading time. For several applications, such as P2P file sharing, MDS erasure codes are more suitable as the network is typically the most constrained resource, not the CPU. Rateless MDS erasure codes also enable to adjust encoding and decoding algorithms as function of dynamic variables to maximize erasure coding gains. State-of-the-art MDS erasure codes are either fixed-rate or have practical limitations. We propose Storm erasure codes, a rateless MDS construction of Reed-Solomon codes over the finite field

$$\mathbb {F}_{p^2}$$

, where

$$p$$

is a Mersenne prime. To the best of our knowledge, we are the first to propose a rateless construction (

$$n$$

can be increased in steps of

$$k$$

) with

$$\varTheta \left( n\log {k}\right) $$

encoding time complexity and

$$\min \left\{ \varTheta \left( n\log {n}\right) ,\varTheta \left( k\log ^2{k}\right) \right\} $$

upper bound for decoding time complexity. We provide the complexity analysis of encoding and decoding algorithms and evaluate Storm’s performance.

Object classification in videos is an important step in many applications such as abnormal event detection in video surveillance, traffic analysis is urban scenes and behavior control in crowded locations. In this work, propose a framework for moving object classification in farfield videos. Much works have been dedicated to accomplish this task. We overview existing works and combine several techniques to implement a real time object classifier with offline training phase. We follow three main steps to classify objects in steady background videos : background subtraction, object tracking and classification. We measure accuracy of our classifier by experiments done using the PETS 2009 dataset.

Position-based cryptography has attracted many researchers’ attention. In mobile Internet, there are lots of position-based security applications. In the paper, one new conception, positioning-protocol-based digital signature is proposed. Based on a secure positioning protocol, one model of positioning-protocol-based digital signature is proposed. In the model, the positioning protocol is bound to digital signature tightly, not loosely. Further, we propose one concrete positioning-protocol-based digital signature scheme and its correctness is proved.

Exploiting random fluctuations of radio channel for key agreement has been investigated for several years; however, these methods of key reconciliation in wireless LANs are vulnerable to attacks especially in case of Line-of-Sight (LOS) channels. In the following paper we will verify whether applying antenna arrays with reconfigurable antennas reduces the number of key bits leaking to the eavesdropper by utilizing two types of attack: Nearest Neighbour Excursion (NNE) and Average RSSI.

Localization methods enable location estimation accurately and provide location information about mobile devices, people, cars, data and equipment. Accurate location detection is a vital process for most of location-based applications such as emergency rescue, in-building guidance, security services, and product tracking in hospitals. This paper addresses localization of student/teacher tablets and school level proxy servers for educational data synchronization. For this purpose, locations of proxy servers and tablets are detected using Android Location API. After localization, if tablets are outside of school, they could access cloud server directly to get educational data and if tablets are in school, they could access data via proxy server. Experimental results show that the proposed technique increases the efficiency in data transfers between the end users and cloud servers.

Two of the most promising paradigms for the next decade are the Social Networks (SN) and Internet of Things (IoT). The challenge will be enabling autonomous interaction among humans and devices when these two paradigms converge. The ITEA2 SITAC project proposes to undertake the challenge of creating a unifying architecture and ‘ecosystem’ comprising platforms, tools and methodologies that enable the seamless connection and cooperation of many types of network-connected entities, whether systems, machines, devices or humans with personal devices. Beyond the state of the art challenges on big data management, management of large number of number of entities and advanced context management are specific role of the SITAC proposed unified architecture. In this scope is also described in detail a project a use case, the

Intouch

, which is an energy aware clustering application for social networking applications, scope of the Portuguese partnership within the project.

One of the most obvious features of ad hoc communication is the analyze of the relationships between the ad hoc network users and their need for communication. On that point, the determination of topologies for efficient broadcast based on property of users of ad hoc networks has attracted a growing interest. In the current work, we propose a method to build a virtual topology that exploits the property of community structure in ad hoc network. The first phase of the proposed method constructs a clustering tree based on structural weight of nodes, while maintaining capacity-efficient links. In the second phase, the algorithm determines a community backbone in order to ensure efficient transmission coverage. Results confirm the generation of a good topology.

In this paper, we proposed a novel Min-Max Ant System algorithm for dynamic resource allocation with many of service classes while maximizing the provider’s utility in service-oriented networks. The model considers a pricing scheme for the offered services and the quality of service (QoS) requirements of each service class, which operates under a probabilistic delay bound constraint. The goal is to investigate how the utility function and the resource allocation respond to changes of various parameters given the QoS requirements of each service class. Our algorithm performance is evaluated through numerical studies and our solution is approximated the optimal solution. The computational results showed that this approach is currently among the best performing algorithms and much better than previous studies for this problem.

In this paper, a sub-optimum detection scheme is proposed for distributed closed-loop quasi orthogonal space time block (D-CL QO-STBC) for two dual antenna relay nodes in decode-and-forward (DF) asynchronous cooperative relay network. The direct transmission (DT) link connection among the source node and the destination node is considered in this network. The proposed scheme is robust against synchronization error and it reduces the receiver complexity as compared to previous work. Furthermore, the maximum available cooperative diversity gain and full transmission rate between the relay nodes and the destination node, and symbol-by-symbol decoding are all achieved. Simulation results are demonstrated to show the proposed scheme for various synchronization errors and effectively eliminate the interference components induced by intersymbol interference (ISI) among the relay nodes.

A cheaper alternative to conventional data communication services is desirable in several scenarios involving mobile devices such as phones. We propose a system for transmission of information over an existing telephony network. This system makes use of “dropped” calls as a transmission medium for carrying data. Since subscribers typically do not incur any charges for dropped calls, our system eliminates the cost associated with conventional methods of mobile data communication.

A “data link” layer implementation, herein called Dropped Call Data Link (DCDL), has been described that uses the above transmission medium. In order to send data using this system an application can define its own information encoding rules, or alternatively, use system-generated encoding rules. Communicating application makes use of the DCDL client-side interface provided by this system to send data. We show that reduction in data communication cost with our system is proportional to the number of mobile clients.

Quality of Experience (QoE) is a crucial characteristic of any multimedia service and must be accounted for during the service development and planning stages. Nonetheless, given its subjective nature, it is extremely difficult to use analytical methods to estimate the average Mean Opinion Score (MOS).

Traditional progressive multimedia streaming is a well researched topic with respect to QoE, however, modern streaming services relying on advanced adaptive video streaming technologies, with specific characteristics, have yet to have an all-encompassing method for QoE estimation, as research work tend to focus on only one, or a small subset, of the technology’s aspects, such as the impact of buffering events, bit-rate change frequency, or initial playout delay.

This paper proposes a model for determining the QoE estimate of a playback session of HTTP adaptive video streaming, encompassing its complete range of characteristics. Several key-metrics are extracted throughout the playback session, and then analyzed by an analytical method able to predict the consumers’ QoE. A subjective QoE survey is conducted according to industry’s best practices and recommendations in order to validate the proposed models. The obtained results show that both subjective and objective estimations produce similar results, hence validating the proposed model.

Nowadays, we have witnessed an exponential growth of the traffic generated by users in mobile communications networks. This need for a greater capacity in mobile networks raises problems for operators, because the demand for network capacity is not always accompanied by the evolution of the available technologies. This represents problems in access networks that result in failures in the customer service and losses to the operator. It is quite important that the service is the best possible for both client and the operator: preventing and resolving network congestion is a common interest. The quality of service is also an important point of great concern, that requires to evaluate the service provided in order to achieve the best satisfaction from the user. However, many challenges still need to be surpassed on current mobile networks.

This paper identifies and resolves cases of congestion in mobile networks, as well as it infers the quality of services provided to the customer. It proposes and implements an architecture that is able to identify problems in access networks, through network monitoring, using metrics gathered by a network management system that gives Key Performance Indicators (KPIs) evaluating the network, and through clients’ information for a specific cell, obtained through probing. Then, a Call Admission Control (CAC) module in the 3GPP Policy and Charging Rules Function (PCRF) is in charge of applying a rule set designed to resolve the case of the detected congestion. The policies chosen directly affect the users in the congested cell, causing the levels of occupancy to drop, and consequently, the cell resources to become stable. Several congestion use cases are identified and demonstrated, which show the effectiveness of the rules applied to the network, services and users.

The technology is facing enormous changes these days. All the objects and all issues can connect to the internet and announce their locations. This vast science, Internet of Things (IoT), is in progress in this decade. One reason is nowadays IoT is applicable in almost all industries. In addition, sensors are widely used in IoT and the production, service and utility cost of sensors has decreased due to an increase in using and producing the complex sensors. To comprehend IoT, one needs to get all the information about the wireless sensors network and understand all the information about the protocols and sensors used in the IoT that collect the data (receive and transmit). In this paper we are going to introduce some types of the sensors and protocols that are used in IoT and examine RFID tags and NFC sensors. The examination of RFID tags and NFC sensors, demonstrates that among all of the sensors and protocols used in IoT field, the RFID tags and NFC sensors are the best ones.

Streamline energy consumption in Wireless Sensor Network (WSN) is and stills a topical problem in which several investigations have undertaken. The aim is to develop mechanisms such those based on routing protocols, for prolonging the network lifetime leading to improve its robustness and fluidity of transmissions, and then ensure an overall stable operation. In this paper, we present a robust and hybrid hierarchical multi-hop routing protocol wherein a dynamic clustering mechanism is implemented for optimal clusters construction. The approach combines successfully heterogonous information in terms of residual energy and signal strength of nodes and allows a multipath search by optimizing end-to-end delay and energy consumption. The effectiveness of the proposed approach is illustrated in simulations. For this purpose, a comparative study with LEACH protocol has been carried out for several networks with different densities.

In the next Generation Networks like Mobile WiMAX, it is highly essential to create a market mechanism that would allow the customer to communicate with Network and negotiate a contract based on some QoS parameters like blocking probability, delay, arrival rate, spectral efficiency, resource allocation and price. However, the mechanisms, rather than technical-oriented scheme, that involve the use of economic theories may provide better solutions to accommodate the high demand of mobile services. The purpose of this research work is to propose and validate mathematical model that study the effect of pricing incentives as an additional strategy for encouraging a more efficient usage of limited network resources. An efficient dynamic pricing scheme for optimal network resource utilization in Mobile WiMAX network has been developed and validated. The percentage improvement of the Cumulative Revenue (CR) generated by the proposed model over the existing model ranges between 25 % and 150 % depending on the values of the Price Leveling Factor (PLF).

In the next Generation Networks like 4G, it is highly essential to create a market mechanism that would allow the customer to communicate with network and negotiate a contract based on some QoS parameters like blocking probability, delay, arrival rate, spectral efficiency, resource allocation and price. However, the mechanisms, rather than technical-oriented scheme, that involve the use of economic theories may provide better solutions to accommodate the high demand of mobile services. The purpose of this research work is to propose and validate mathematical model that study the effect of pricing incentives as an additional strategy that optimally shapes the users’ traffic in terms of delay, service class partitioning, and prioritization for wireless users in Mobile WiMAX network. The percentage improvement of the Cumulative Revenue (CR) generated by the proposed model over Yaipairoj model ranges between 25 % and 100 %. The proposed model is able to reduce congestion by 21 %.

This paper describes outdoor field measurements in television white spaces (TVWS) carried out in Munich, Germany. Fixed and mobile measurements in rural, sub-urban and urban scenarios showed that the modified Hata model is appropriate to describe the path loss over distances up to few kilometers, and may be used in the process to populate a geo-location database.

GREEN-T is a CELTIC-Plus project which lists as one of its goals to develop and implement a 4G emulator, allowing the end-user to evaluate the quality of experience of real-time based services. There are many simulators for various wireless technologies (LTE, UMTS, WI-FI) and almost all of them have as outputs different values, such as bitrate, received power, SNR, depending on the simulation type. In spite of the reliability of these simulators, it is difficult to understand the impact of those values in real communication. This paper describes the implementation of an LTE emulator based on system simulator results where the end user can experience real time and real scenario communication conditions and interactivity with applications. This platform aims to convert the merely numerical values, obtained through the use of simulation tools, to a real-time experience for the simulated scenario. We demonstrate a 2Mbits/s bitrate video application, with a BER value of around

$$ 1 \times 10^{ - 6} $$

or a received power around 1 nW in a simulation scenario. In spite of the fact that the implementation was based on the LTE, protocols of other 4G and 5G networks will be allowed to be used and tested, since they are IP based protocols like LTE.

This paper proposes a tuneable band-rejected miniaturised monopole antenna. The band-notching was achieved by printing an inner chorded crescent shape over the surface of the substrate. By placing a small varactor between the inner and outer arches, the centre frequency of each notch can be individually shifted downwards. The design of the proposed structure has a controllable rejection in the range from 2.38 to 3.87 GHz maintaining a wideband performance from 1.5 to 5 GHz based on VSWR ≤ 2. The antenna prototype was fabricated and tested. Simulated and measured results are performed and analysed. With a compact size, the proposed monopole antenna may well work as an internal antenna in a portable device.

Previous cluster based group key management schemes for wireless mobile multicast communication lack efficiency in rekeying the group key if high mobility users concurrently subscribe to multiple multicast services that co-exist in the same network. This paper proposes an efficient multi-service group key management scheme suitable for high mobility users which perform frequent handoffs while participating seamlessly in multiple multicast services. The users are expected to drop subscriptions after multiple cluster visits hence inducing huge key management overhead due to rekeying the previously visited cluster keys. However we adopt our already proposed SMGKM system with completely decentralised authentication and key management functions to address demands for high mobility environment with same level of security and less overhead. Through comparisons with existing schemes and simulations, SMGKM shows resource economy in terms of rekeying communication overhead in high mobility environment with multi-leaves.

Simplified designs of multi-antenna systems with optimum efficiency are receiving attentions. Such simplicities also involve low cost architectures. In this study, we report an evaluation of a new multi-antenna scheme, namely, spatial modulation (SM) that is compared with quasi-orthogonal space time block codes (QOSTBC) scheme over Rayleigh fading channel. The SM scheme has been, earlier, compared with space time block codes (STBC) – a two antenna transmit diversity scheme that achieves full diversity when only two antennas are used. This is extended to QOSTBC scheme that absolves some decoding limitations to attain full diversity. It will be shown that, using the QOSTBC of similar architecture with the SM, even better performance can be achieved in favour of QOSTBC.

The degree of insecurity occasioned by fraudulent practices in Nigeria has been of great concern economically, especially as it relates to overseas transactions. This paper was designed to mitigate this problem for Nigeria and countries with similar dispositions. Based on a survey involving field trip to Nigeria, the paper examines the general security situation in Nigeria and its mutual impacts with computerisation, miniaturisation and Location-Based Authentication (LBA). It was discovered that both computerisation and miniaturisation had some negative effects on cyber-security, as these were being exploited by fraudsters, especially using ‘advance fee fraud;’ popularly called

419

. As a countermeasure, the research examined the possibility of using LBA and further digitisation of the GSM Mobile country codes down to City/Area codes along with GSM Mobile/Global Positioning System (GPS) authentications. Where necessary, these could be combined with the use of a web-based Secret Sharing Scheme for services with very high security demands. The anticipated challenges were also examined and considered to be of negligible impacts; especially roaming.

Passive and active devices are essential devices in mobile and base stations’ transceiver. Consequently, these devices dominated the large part of the PCB of the today’s transceiver. However, the tomorrow’s mobile terminals without circuit tunability would be extremely large in size to accommodate present and future radio access technologies (RATs). The stand-alone transceiver for one single RAT is comprised of single passive and active devices and adding two or more RATs for the same transceiver would require adding two or more devices, since all of these RATs standards work on different frequency bands. Apparently, without tunability approach, this will increase the complexity of the system design and will cover a large part of the circuit space leading to power consumptions, loss which results to the poor efficiency of the transceiver. In this work, a miniaturized RF MEMS tunable bandpass is developed to operate in the frequency range from 1.8 to 2.6 GHz.

With the massive deployment of broadband access to the end-users and the improved hardware capabilities of end devices, peer-to-peer (P2P) networking paradigm is consistently gaining terrain over the typical client-server approach. In most of the modern countries, today’s Internet connectivity has sufficient conditions to unleash P2P applications such as video-on-demand or real-time television. It is known that the use of P2P based systems to distribute delay sensitive applications raises technical problems mainly associated with the system’s instability caused by the peer churn effect. In this article, we propose a framework to distribute delay sensitive 3D video content using a hybrid client-server and P2P approach. The proposed platform uses P2P application-level multicast trees at the access networks, delegating typical server operations at super-peers who are domain and geographically distributed. Results are based on real testbed implementation show quick reaction at peer level.