Special issue: Body Area Networks applications and technologies

Vol. 66, n° 3-4, March-April 2011
Content available on SpringerLink

Guest editors
Laurent Ouvry, CEA-Leti, Grenoble, France
Bin Zhen, Huawei, Beijing, China
Simon Cotton, ECIT Institute, Belfast, Ireland


Laurent Ouvry1 · Bin Zhen2 · Simon Cotton3
1.CEA-Leti, Grenoble, France
2.Wireless Research Department, Huawei, China
3.Royal Academy of Engineering Research Fellow, ECIT Institute, Belfast, Ireland

Antenna design and channel modeling in the BAN context—part I: antennas

Christophe Roblin1, Jean-Marc Laheurte2, Raffaele D’Errico3, Azeddine Gati3 and David Lautru5, et al.
1. ENSTA Paris-Tech, France
2. ESYCOM, Université Paris-Est Marne-La-Vallée, France
3. CEA-Leti
4. Orange Lab., Issy-les-Moulineaux, France
5. UPMC, Université Paris 06

Abstract The first results achieved in the French ANR (National Research Agency) project BANET (Body Area NEtwork and Technologies) are presented (Part I). This project mainly deals with the antenna design in the context of Body Area Networks applications and channel characterization. General conclusions are drawn on the body impact on the antenna performance for on–on and in–on communications (Medical Implant Communication Systems). Narrow-band and ultra-wideband contexts are addressed both numerically and experimentally, and it is shown that design questions are significantly different for each case, leading to different constraints and guidelines. For narrow-band antennas, an alternative and original approach of desensitization using ferrite sheets is proposed and compared to classical techniques based on ground-plane screening. The characterization of numerical phantoms is also analyzed with narrow-band canonical antennas. For the specific on–on scenario, morphologies and electrical properties of the human tissues are also included in the topics of interest. For ultra-wideband antennas, focus is put on planar balanced designs, notably to reduce harmful “cable effects” occurring during the antenna characterization or the channel sounding. For both types of antennas, the main parameter under study is the distance to the body, which has a significant influence.

Keywords Body area network · Antenna · Input impedance · Total efficiency · Radiation pattern · Antenna miniaturization · UWB · Body absorption · Human tissues permittivity · Medical implants · MICS · On-body channel · In on-body channel

Antenna design and channel modeling in the BAN context—part II: channel

Christophe Roblin1, Jean-Marc Laheurte2, Raffaele D’Errico3, Azeddine Gati3 and David Lautru5, et al.
1. ENSTA Paris-Tech, France
2. ESYCOM, Université Paris-Est Marne-La-Vallée, France
3. CEA-Leti
4. Orange Lab., Issy-les-Moulineaux, France
5. UPMC, Université Paris 06

Abstract The first results achieved in the French ANR (National Research Agency) project BANET (Body Area NEtwork and Technologies) concerning the channel characterization and modeling aspects of Body Area Networks (BANs) are presented (part II). A scenario-based approach is used to determine the BAN statistical behavior, trends, and eventually models, from numerous measurement campaigns. Measurement setups are carefully described in the UWB context. The numerous sources of variability of the channel are addressed. A particular focus is put on the time-variant channel, showing notably that it is the main cause of the slow fading variance. Issues related to the data processing and the measurement uncertainties are also described.

Keywords  Body Area Network · Antenna · UWB · Path loss · Propagation · Body absorption · Human tissues permittivity · BAN propagation channel · UWB BAN channel · Channel measurements · Channel models · On-body channel

A UWB WBAN channel model based on a pseudo-dynamic measurement

Attaphongse Taparugssanagorn1&2, Bin Zhen3, Raffaello Tesi1, Matti Hämäläinen1, Jari Iinatti1 and Ryuji Kohno1, 2&3
1. Centre for Wireless Communications, University of Oulu, Finland
2. Center of Medical Information & Communication Technology, Yokohama National University, Japan
3. National Institute of Information and Communications Technology (NICT), Yokosuka, Japan

Abstract In this paper, we expand the knowledge of the ultra-wideband (UWB) channel in the frequency range of 3.1–10 GHz in close proximity of a human body. The channels under dynamic conditions due to the effect of body motions are studied through the pseudo-dynamic measurement method. Firstly, the first-order statistics of the channels, namely, amplitude distributions are investigated. Secondly, the dynamic features of the channels are also studied through the second-order statistics of the channels, namely, the good and bad channel durations as well as the LCR, which are important for a cross-layer design. Three strongest peaks capturing most of the energy of the channel are taken into account. Finally, a two-state alternating Weibull renewal process model is proposed. The model provides good usability with low complexity and can then be used to better design communication network protocols for WBANs. In addition, for the sake of designing a non-coherent receiver, the dynamic delay spread of the channel, which determines an energy collector detecting the signal energy over a time window, is investigated.

Keywords Body-centric wireless communications · Medical wireless sensors · Renewal process · Hidden–Markov model

First- and second-order statistical characterizations of the dynamic body area propagation channel of various bandwidths

David B. Smith1, Leif W. Hanlen1, Jian (Andrew) Zhang2, Dino Miniutti1, David Rodda1 and Ben Gilbert3
1. National ICT Australia
2. ICT Centre, CSIRO, Australia
3. Air-Services Australia

Abstract Comprehensive statistical characterizations of the dynamic narrowband on-body area and on-body to off-body area channels are presented. These characterizations are based on real-time measurements of the time domain channel response at carrier frequencies near the 900- and 2,400-MHz industrial, scientific, and medical bands and at a carrier frequency near the 402-MHz medical implant communications band. We consider varying amounts of body movement, numerous transmit–receive pair locations on the human body, and various bandwidths. We also consider long periods, i.e., hours of everyday activity (predominantly indoor scenarios), for on-body channel characterization. Various adult human test subjects are used. It is shown, by applying the Akaike information criterion, that the Weibull and Gamma distributions generally fit agglomerates of received signal amplitude data and that in various individual cases the Lognormal distribution provides a good fit. We also characterize fade duration and fade depth with direct matching to second-order temporal statistics. These first- and second-order characterizations have important utility in the design and evaluation of body area communications systems.

Keywords Body area networks · Channel modeling · Akaike information criterion · Fading channels · Radio propagation · Wireless communication

Path gain models for on-body communication systems at 2.4 and 5.8 GHz

Anda R. Guraliuc, Andrea A. Serra, Paolo Nepa and Giuliano Manara
Department of Information Engineering, University of Pisa, Italy

Abstract In this paper, a couple of path gain models for on-body communication systems are analyzed and compared. The study is focused on the characterization of the propagation channel between two wearable devices placed on a human body, and operating at 2.4 and 5.8 GHz. Wearable wireless low-cost commercial modules and low-profile annular ring slot antennas were used, and measurements were performed for different radio links on a human body. Measurement results have been compared with CST Microwave Studio simulations by resorting to simplified body models like flat, cylindrical, spherical, and ellipsoidal canonical geometries. Characteristic parameters appearing in the propagation models have been calculated for the analyzed on-body channels and summarized in a concluding table.

Keywords Propagation channel characterization · Path gain modeling · On-body area networks

Performance evaluation of direct and cooperative transmissions in body area networks

Paul Ferrand1, Mickael Maman2, Claire Goursaud1, Jean-Marie Gorce1 and Laurent Ouvry2
1. Université de Lyon, INRIA, INSA-Lyon, CITI, France
2. CEA-Leti Minatec, Grenoble, France

Abstract Body area networks (BAN) offer amazing perspectives to instrument and support humans in many aspects of their life. Among all possible applications, this paper focuses on body monitoring applications having a body equipped with a set of sensors transmitting in real time their measures to a common sink. In this context, at the application level, the network fits with a star topology, which is quite usual in the broad scope of wireless networks. Unfortunately, the structure of the network at the physical layer is totally different. Indeed, due to the specificity of BAN radio channel features, all radio links are not stationary and all sensors suffer from link losses during independent time frames. In wireless networks, link losses are often coped with multi-hop transmission schemes to ensure a good connectivity. However, since the radio links are not stationary, the multi-hop routes should adapt quickly to BAN changes. We instead propose in this work a different approach based on opportunistic relaying. The concept relies on electing some sensors to support the transmission of other ones having a worst connection. Instead of changing the relay time to time, we rather select a relay node from a statistical perspective. We evaluate this approach from a theoretical point of view and on realistic simulations using the packet error rate outage probability as a performance criterion.

Keywords Body area networks · Opportunistic relaying · PER outage probability

Priority-guaranteed MAC protocol for emerging wireless body area networks

Yan Zhang and Guido Dolmans
Wireless Group, Stichting IMEC Nederland

Abstract The newly emerging wireless body area networks (WBANs) are intended to support both medical applications and consumer electronic (CE) applications. These two types of applications present diverse service requirements. To satisfy both medical and CE applications with a uniform medium access control (MAC) protocol becomes a new challenge for the WBAN. Addressing this problem, a priority-guaranteed MAC protocol is proposed in this paper. In this protocol, data channels are separated from control channels to support collision-free high data rate communication for CE applications. Priority-specific control channels are adopted to provide priority guarantee to life-critical medical applications. Traffic-specific data channels are deployed to improve resource efficiency and latency performance. Moreover, in order to further minimize energy consumption and access latency, an asynchronous wakeup trigger mode is proposed as an enhancement to the priority traffic. Monte Carlo simulations are carried out for performance evaluation. As compared with IEEE 802.15.4 MAC and its improved versions, the priority-guaranteed MAC demonstrates significant improvements on throughput and energy efficiency with a tolerable penalty on latency performance of bursty traffic in CE applications. Therefore, the customized priority-guaranteed MAC satisfies the service requirements of WBAN by making tradeoff among the performances of different applications.

Keywords  MAC · WBAN · Priority · IEEE 802.15.6 · Medical · CE · Throughput · Energy · Latency

Open Topics

The AutoI approach for the orchestration of autonomic networks

Daniel Fernandes Macedo1, Zeinab Movahedi1, Javier Rubio-Loyola2, Antonio Astorga3, Giannis Koumoutsos4 and Guy Pujolle1
1. Laboratoire d’Informatique Paris VI-Paris Universitas, France
2. CINVESTAV Tamaulipas, Victoria, Mexico
3. Universitat Politècnica de Catalunya, Barcelona, Spain
4. University of Patras, Greece

Abstract Existing services require assurable end-to-end quality of service, security and reliability constraints. Therefore, the networks involved in the transport of the data must cooperate to satisfy those constraints. In a next generation Internet, each of those networks may be managed by different entities. Furthermore, their policies and service level agreements (SLAs) will differ, as well as the autonomic management systems controlling them. In this context, we in the Autonomic Internet (AutoI) consortium propose the Orchestration Plane (OP), which promotes the interaction among different Autonomic Management Systems (AMSs). The OP mediates the communication and negotiation among AMSs, ensuring that their SLAs and policies meet the requirements needed for the provisioning of the services. It also simplifies the federation of domains and the distribution of new services in virtualised network environments.

Keywords Network management · Autonomic networking · Management orchestration · Next-generation internet

New super-orthogonal space-time trellis codes using differential M-PSK for noncoherent mobile communication systems with two transmit antennas

Corneliu Eugen D. Sterian1, Yuanyuan Ma2, Matthias Pätzold2, Ion Bǎnicǎ1 and Huaqiang He2
1. Polytechnic University of Bucharest, Romania
2. University of Agder, Grimstad, Norway

Abstract In this paper, we develop super-orthogonal space-time trellis codes (SOSTTCs) using differential binary phase-shift keying, quadriphase-shift keying and eight-phase shift keying for noncoherent communication systems with two transmit antennas without channel state information at the receiver. Based on a differential encoding scheme proposed by Tarokh and Jafarkhani, we propose a new decoding algorithm with reduced decoding complexity. To evaluate the performance of the SOSTTCs by way of computer simulations, a geometric two-ring channel model is employed throughout. The simulation results show that the new decoding algorithm has the same decoding performance compared with the traditional decoding strategy, while it reduces significantly the overall computing complexity. As expected the system performance depends greatly on the antenna spacing and on the angular spread of the incoming waves. For fair comparison, we also design SOSTTCs for coherent detection of the same complexity as those demonstrated for the noncoherent case. As in the case of classical single antenna transmission systems, the coherent scheme outperforms the differential one by approximately 3 dB for SOSTTCs as well.

Keywords Differential detection · Noncoherent communications · Super-orthogonal space-time trellis codes