Radio Paradigm Research Articles

Spectrum sensing: A distributed approach for cognitive terminals

Cognitive radios is emerging in research laboratories as a promising wireless paradigm, which will integrate benefits of software defined radio with a complete aware communication behavior. To reach this goal many issues remain still open, such as powerful algorithms for sensing the external environment. This paper presents a further step in the direction of allowing cooperative spectrum sensing in peer-to-peer cognitive networks by using distributed detection theory. The approach aims at improving the radio awareness with respect to stand alone scenario as it is shown with theoretical and experimental results

Capacity of Wireless Ad Hoc Networks with Opportunistic Collaborative Communications

Optimal multihop routing in ad hoc networks requires the exchange of control messages at the MAC and network layer in order to set up the (centralized) optimization problem. Distributed opportunistic space-time collaboration (OST) is a valid alternative that avoids this drawback by enabling opportunistic cooperation with the source at the physical layer. In this paper, the performance of OST is investigated. It is shown analytically that opportunistic collaboration outperforms (centralized) optimal multihop in case spatial reuse (i.e., the simultaneous transmission of more than one data stream) is not allowed by the transmission protocol. Conversely, in case spatial reuse is possible, the relative performance between the two protocols has to be studied case by case in terms of the corresponding capacity regions, given the topology and the physical parameters of network at hand. Simulation results confirm that opportunistic collaborative communication is a promising paradigm for wireless ad hoc networks that deserves further investigation.

A survey on ultra wide band medium access control schemes

Ultra wideband (UWB) technology based primarily on the impulse radio paradigm has a huge potential for revolutionizing the world of digital communications especially wireless communications. UWB provides the integrated capabilities of data communications, advanced radar and precision tracking, location, imperceptibility and low power operation. It is therefore ideally suited for the development of robust and rapid wireless networks in complex and hostile environments. The distinct physical layer properties of the UWB technology warrants efficient design of medium access control (MAC) protocols. This paper introduces the unique UWB physical characteristics compared to the existing wireless technologies and discusses current research on MAC protocols for UWB. This report surveys most of the MAC protocols proposed so far for UWB, and may instigate further activities on this important and evolving technology.

Tackling 4G challenges with "TACT" - Design and optimization of 4G radio receivers with a transceiver architecture comparison tool (TACT)

Current integration trends imposed by the market are pushing toward the software radio paradigm. 4G radio receivers, where different wireless standards converge, make RF engineers face harder and harder challenges. Electronic design automation (EDA) tools play an increasing role in the design and verification of wireless system. This article presents a transceiver architecture comparison tool (TACT) which is a hierarchical, user-friendly, Matlab-based tool. It automates the design-space exploration procedure for 4G (fourth generation) wireless receivers. An example that considers a multistandard wideband code division multiple access (WCDMA)/wireless local area network (WLAN) receiver was also presented to illustrate the capabilities of TACT

Research advances in cognitive ultra wide band radio and their application to sensor networks

The paper illustrates the novel concept of Cognitive UWB Radio, a wireless system based on UWB transmission able to self-adapt to the characteristics of the surrounding environment. First, salient features of UWB transmission are reviewed, and then, application of UWB characteristics to the problem of cognitive radio systems is discussed. Current ongoing studies and achieved results on a possible physical layer based on Prolate Spheroidal Wave Functions and consistent with the Cognitive UWB Radio paradigm are presented and analyzed, and their application to the sensor network scenario is discussed.

A Paradigm for Quality-of-Service in Wireless Ad Hoc Networks Using Synchronous Signaling and Node States

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.

Radio resource sharing for ad hoc networking with UWB

Ultra-wideband (UWB) radio is becoming a promising field for new generation's digital communication systems. This technique, based mainly on the impulse radio paradigm, offers great flexibility and shows enormous potential in view of a future broadband wireless access. We present the main principles to design a multiaccess scheme based on UWB. The potential of UWB is exploited within a distributed ad hoc wireless system, where we describe the principles for the definition of a medium-access control (MAC) for mobile computing applications and we analyze the main performance results derived from simulations. A general framework for radio resource sharing is outlined for classes of traffic requiring both elastic-dynamic and guaranteed-reserved bandwidth. Then, we discuss the issue of supporting the proposed radio resource sharing scheme by means of a distributed MAC protocol.

Real Voices in the Technological Wilderness Using ethnographic methods to challenge global wireless paradigms

Cet article s’interesse a la facon dont les entreprises utilisent les recherches ethnographiques pour concevoir, fabriquer et lancer des produits ou des services repondant aux besoins, attestes ou non, des consommateurs. Meme si bon nombre de ces produits sont presents sur la scene economique a l’echelle mondiale, le marche est loin d’etre homogene. Les dogmes et les pratiques culturelles exercent une forte influence sur la signification donnee a de tels objets et donc sur leur utilisation. Si un produit ne beneficie pas d’un echo culturel, il pourra etre rejete par les consommateurs quel que soit son caractere innovateur ou l’avancee technologique qu ’il represente. L’article se concentre plus particulierement sur l’usage du telephone mobile et du service I-mode au Japon. Les methodes de recherche utilisees sont decrites et notamment la facon dont elles mettent en lumiere les processus sociaux et culturels susceptibles d’influencer l’adoption d’un telephone mobile. Afin de developper le secteur des telephones sans fil et d’elaborer de nouvelles techniques de communications mobiles qui puissent satisfaire les consommateurs aussi bien sur le plan culturel, qu’emotionnel et technique, il est necessaire de repenser le concept de « paradigme mondial » tel qu ’il est envisage aujourd’hui. Dans un premier temps, il est tout a fait crucial d’ajouter une dimension anthropologique a la conception des objets, ce qui devrait aider les entreprises de telecommunication a definir une nouvelle generation de produits et de services en phase avec le monde des telecommunications mobiles.

Software development and verification of dynamic real-time distributed systems based on the radio broadcast paradigm

The combination of an increased power of computer systems and a marriage between computing and communication causes an enormous increase in the complexity of applications in almost all domains. This also applies to the real-time and the embedded domains, where onstruction of distributed applications is a major research area. In our research, we develop a framework for the systematic development of distributed real-time control applications. We emphasize the use of pragmatic sound approaches in the design steps of the development process, preferrably based on some common architectural style. For analyzing and validating critical elements of design and implementation, we emphasize the use of formalisms, however. Complexity of applications is such that for real verification and validation, proof or model-checking tecniques are required. We use formalized abstraction as a technique for obtaining the appropriate templates from design and implementation. These abstractions are then dealt with in a mode-checking and analysis tool set. In this paper we show some elements of our approach, in particular we describe the architectural style that we are using, the Radio Broadcast Paradigm, and we demonstrate the viability of our approach by showing a case study.