Navid Nikaein

DDR: distributed dynamic routing algorithm for mobile ad hoc networks

This paper presents an alternative simple loop-free bandwidth-efficient distributed routing algorithm for mobile ad hoc networks, denoted as distributed dynamic routing (DDR). Although DDR benefits from classical concepts like zone and forest, unlike previous solutions it achieves several goals at the same time. Firstly, it provides different mechanisms to drastically reduce routing complexity and improve delay performance. Secondly, it is infrastructureless in a strong sense: it does not even require a physical location information. Finally, zone naming is performed dynamically and broadcasting is reduced noticeably.

CrossTalk: cross-layer decision support based on global knowledge

The dynamic nature of ad hoc networks makes system design a challenging task. Mobile ad hoc networks suffer from severe performance problems due to the shared, interference-prone, and unreliable medium. Routes can be unstable due to mobility and energy can be a limiting factor for typical devices such as PDAs, mobile phones, and sensor nodes. In such environments cross-layer architectures are a promising new approach, as they can adapt protocol behavior to changing networking conditions. This article introduces CrossTalk, a cross-layer architecture that aims at achieving global objectives with local behavior. It further compares CrossTalk with other cross-layer architectures proposed. Finally, it analyzes the quality of the information provided by the architecture and presents a reference application to demonstrate the effectiveness of the general approach.

An IoT gateway centric architecture to provide novel M2M services

This paper proposes an innovative Internet of Things (IoT) architecture that allows real time interaction between mobile clients and smart/legacy things (sensors and actuators) via a wireless gateway. The novel services provided are: (i) dynamic discovery of M2M device and endpoints by the clients, (ii) managing connection with non-smart things connected over modbus, (iii) associate metadata to sensor and actuator measurements using Sensor Markup Language (SenML) representation and (iv) extending the current capabilities of SenML to support actuator control from mobile clients. These clients are equipped with an end-user application that initiates the discovery phase to learn about the devices and endpoints (sensors and actuators) connected to the wireless gateway. Then the user can select desired sensors to receive and display sensor metadata and control actuators from the mobile device. Prototypes of the mobile application and the wireless gateway have been implemented to validate the entire architecture. The gateway is implemented using RESTful web services and currently runs in a Google App Engine. Two real life scenarios are discussed that can be implemented using the architecture. Finally overall contributions and future research scopes are summarized.

Survey, comparison and evaluation of cross platform mobile application development tools

Mobile application development is becoming more challenging with diverse platforms and their software development kits. In order to reduce the cost of development and reach out to maximum users across several platforms, developers are migrating to cross platform application development tools. In this paper, we provide several decision criteria beyond the portability concerns for choosing suitable cross platform tool for application development. The desirable requirements in a cross platform framework are identified. A general architecture for cross platform application development is discussed. Then a survey of several write once run anywhere tools (PhoneGap, Titanium, Sencha Touch) are provided along with a classification and comparison among the tools. To examine the performance in terms of CPU, memory usage, power consumption, Android test applications are developed using such tools. It is found that PhoneGap consumes less memory, CPU and power since it does not included dedicated UI components. Finally the paper summarizes the contributions and concludes with some future directions.

OpenAirInterface: A Flexible Platform for 5G Research

Driven by the need to cope with exponentially growing mobile data traffic and to support new traffic types from massive numbers of machine-type devices, academia and industry are thinking beyond the current generation of mobile cellular networks to chalk a path towards fifth generation (5G) mobile networks. Several new approaches and technologies are being considered as potential elements making up such a future mobile network, including cloud RANs, application of SDN principles, exploiting new and unused portions of spectrum, use of massive MIMO and full-duplex communications. Research on these technologies requires realistic and flexible experimentation platforms that offer a wide range of experimentation modes from real-world experimentation to controlled and scalable evaluations while at the same time retaining backward compatibility with current generation systems. Towards this end, we present OpenAirInterface (OAI) as a suitably flexible platform. In addition, we discuss the use of OAI in the context of several widely mentioned 5G research directions.

Network Store: Exploring Slicing in Future 5G Networks

In this paper, we provide a revolutionary vision of 5G networks, in which SDN technologies are used for the programmability of the wireless network, and where a NFV-ready network store is provided to Mobile Network Operators (MNO), Enterprises, and Over-The-Top (OTT) third parties. The proposed network serves as a digital distribution platform of programmable Virtualized Network Functions (VNFs) that enables 5G application use-cases. Currently existing application stores, such as Apples App Store for iOS applications, Googles Play Store for Android, or Ubuntus Software Center, deliver applications to user specific software platforms. Our vision is to provide a digital marketplace, gathering 5G enabling Network Applications and Network Functions, written to run on top of commodity cloud infrastructures, connected to remote radio heads (RRH). The 5G Network Store will be the same to the network provider as the application store is currently to a software platform.

LTE/LTE-A Discontinuous Reception Modeling for Machine Type Communications

Machine type communications (MTC) are considered as key applications in LTE/LTE-A networks, for which lowering power consumption is among the primary requirements. In this paper, we model the LTE/LTE-A discontinuous reception (DRX) mechanism for MTC applications based on a Semi-Markov chain model. With our model the power saving factor and wake up latency can be accurately estimated for a given choice of DRX parameters, thus allowing to select the ones presenting the best tradeoff. The proposed model is validated through simulations. We also investigate the effect of different DRX parameters on performance.

Processing Radio Access Network Functions in the Cloud: Critical Issues and Modeling

Commoditization and virtualization of wireless networks are changing the economics of mobile networks to help network providers (e.g., MNO, MVNO) move from proprietary and bespoke hardware and software platforms toward an open, cost-effective, and flexible cellular ecosystem. Cloud radio access network is a novel architecture that perform the required base band and protocol processing on a centralized computing resources or a cloud infrastructure. This replaces traditional base stations with distributed (passive) radio elements with much smaller footprints than the traditional base station and a remote pool of base band units allowing for simpler network densification. This paper investigates three critical issues for the cloudification of the current LTE/LTE-A radio access network. Extensive experimentations have been performed based on the OpenAirInterface simulators to characterise the base band processing time under different conditions. Based on the results, an accurate model is proposed to compute the total uplink and downlink processing load as a function of bandwidth, modulation and coding scheme, and virtualization platforms. The results also reveal the feasible virtualization approach towards a cloud-native radio access network.

Contention Based Access for Machine-Type Communications over LTE

To enable the efficient and low latency machine-type communications (MTC) over long term evolution (LTE), a contention based access (CBA) method is proposed. With CBA, UEs transmit packets on the randomly selected resource without having any UE specific scheduled resources. To address the problem of collision caused by CBA in high traffic load, eNB exploits the MU-MIMO detection technique to decode radio network temporary identifier (RNTI) of the collided UEs and use this information to perform a regular scheduling in subsequent subframe. Detailed low layer signaling enhancement to implement CBA technique in current LTE specification (Rel. 10) is also presented. Simulation results demonstrate that the CBA significanlty outperforms the existing uplink channel access methods.

Machine-to-machine: An emerging communication paradigm

In recent years, the number of networked machines and/or devices, such as those encountered in automatic meter readers, smart plants, vending machines or in remote monitoring applications, has dramatically increased. As a result, we have witnessed the emergence of the so-called machine-to-machine (M2M) communication paradigm. M2M devices are often characterised by very modest data rates, low mobility and stringent cost and energy efficiency requirements, along with the need to communicate over a wide area. Besides, in the coming years, M2M devices are expected to significantly outnumber voice and (often bandwidth-hungry) data terminals. All this entails a major redesign of future (low power) wireless and cellular networks, which were originally conceived with human-to-human communications in mind. This opens a wide research area for M2M communications, including investigations on scalability, wide area coverage, energy efficiency, spectral efficiency, heterogeneity, cooperation, security and inter-networking architectures. To this end, the European Telecommunication Standards Institute’s M2M Technical Committee has proposed a hybrid architecture whereby cellular-enabled gateways can act as traffic aggregation and protocol translation points for their capillary (i.e. wireless sensor) networks. Capillary networks, in turn, are composed of a potentially high number of devices (namely, sensors and actuators) equipped with short-range radio interfaces, often compliant with IEEE802.15.4 and IEEE 802.11-related standards. Current standardisation activities in Third Generation Partnership Project (3GPP) encompass a number of optimisations specifically addressing machine-type communication needs. Moreover, IP for smart objects is assembling a protocol stack from standards being finalised at the IEEE and IETF. This special issue aims at gathering recent advances in the areas of advanced M2M communication systems, and technologies, with the perspective of current M2M-related standardisation activities in 3GPP, ETSI, IEEE, IETF and IP for smart objects. In addition to the submissions from the open call, we invited authors of a number of selected papers from the International Workshop on M2M Communications held in conjunction with IEEE Globecom’12 (Anaheim, CA), and the International Workshop on M2M Communication Technologies and Systems (Wuxi, China) to produce extended versions of their manuscripts. After extensive and careful reviews of the numerous manuscripts we received, we accepted eight papers that, in our opinion, bear the highest quality and the best fit with the topic of this Special Issue. The accepted papers address three main research areas: random access and scheduling, energy consumption and energy efficiency, and architectural aspects. The first group of papers report on recent advances on random access and scheduling methods for Machine-Type Communications (MTC). In their contribution, Thomsen, Pratas, Stefanovic and Popovski investigate a novel random access method, inspired in that of LTE, which significantly increases the amount of contention resources without increasing system resources, such as contention sub-frames and preambles. This, as it is shown in the paper, enables a massive support of MTC users that is beyond the reach of current systems. Complementarily, Gerasimenko, Petrov, Galinina and Andreev analyse the impact of MTC on the performance of random access channels in a 3GPP LTE-advanced context. To that aim, the authors propose a novel evaluation methodology, fully compatible with the 3GPP test cases, to analyse, on the one hand, the performance of RACH channels in overloaded MTC scenarios and, on the other, that of regular MTC operation. Both energy consumption and latency aspects are explicitly taken into account in this work. Still in a context of LTE/LTE-A cellular networks, Gotsis, Lioumpas and Alexiou focus on time-controlled scheduling strategies to support diverse M2M traffic characteristics and quality of service requirements. First, the authors propose analytical models to predict system performance in scenarios with multiple traffic classes and diverse quality of service requirements. Then, they modify an existing scheduling algorithm to improve the performance of low priority M2M device groups. Finally, the proposed scheme is validated through extensive system-level simulations. The applicability of compressed sensing techniques for joint detection of sensor node activity and transmitted data is the main research topic addressed in the paper by Bockelmann, Schepker and Dekorsy. Such an approach facilitates the design of low overhead communication schemes not requiring additional control signaling for resource allocation and management. Computer simulation results reveal that activity detection and, in particular, the missed detection rate (rather than false alarm rate) determines the performance of the overall system. The next group of papers revolve around energy consumption and energy efficiency aspects. Specifically, Bartoli, Hernández-Serrano, León, Kountouris and Barthel focus on authentication schemes capable of discarding non-intended and/or non-legitimate packets just after the