INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING Int. J. Satell. Commun. Network. 2004; 22:587–610 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/sat.779 Mobile Internet access using satellite networks P. Loreti 1,z , M. Luglio 1,n,y , R. Kapoor 2,} , J. Stepanek 2,} , M. Gerla k,2 , F. Vatalaro 1,** and M. A. Vazquez-Castro 3,yy 1 Dipartimento di Ingegneria Elettronica, Universit " a di Roma Tor Vergata, Via di Tor Vergata 110, 00133 Rome, Italy 2 Computer Science Department, University of California Los Angeles, Boelter Hall, Los Angeles CA, 90095 U.S.A. 3 Dept. de Tecnolog ! ıas de las Comunicaciones, Universidad Carlos III de Madrid, Avda. del la Universidad 30, 28911 Leganes, Madrid, Spain SUMMARY Satellites offer a promising alternative for mobile access to the Internet by both pedestrians, and more importantly, from vehicles. As such, satellites provide an essential complement to the cellular radio (UMTS) infrastructure in sparsely populated areas where high bandwidth UMTS cells cannot be economically deployed. In this paper, we analyse various mobile Internet applications in representative urban scenarios for two LEO constellations (one with polar orbits and the other with inclined orbits), as well as for some simple GEO configurations. To this end, we develop a satellite channel propagation model that includes shadowing from surrounding building skylines based on actual data in a built-up area. Using these tools, we analyse various Internet applications and the performance of various TCP schemes in different topologies. Copyright # 2004 John Wiley & Sons, Ltd. KEY WORDS: GEO; LEO; mobile satellite; TCP 1. INTRODUCTION Mobile access to the Internet is becoming extremely popular in part because users depend on the Internet for many of the activities that make up their daily routine (business, entertainment, education, family, etc.), and thus wish to extend connectivity to the times when they are away from their home or office. ‘Nomadic’ Internet users are supported in their request for efficient, mobile access by a myriad of new networking technologies, from UMTS to Wireless LANs, Metricom and Bluetooth. One ‘old’ technology, which may prove very effective for mobile Internet applications, is satellite technology. Received April 2002 Revised June 2002 Accepted November 2003 Copyright # 2004 John Wiley & Sons, Ltd. y E-mail: luglio@uniroma2.it z E-mail: loreti@ing.uniroma2.it n Correspondence to: M. Luglio, Dipartimento di Ingegneria Elettronica, Universit " a di Roma Tor Vergata, Via di Tor Vergata 110, 00133 Rome, Italy. } E-mail: rohitk@cs.ucla.edu } E-mail: stepanek@cs.ucla.edu k E-mail: gerla@cs.ucla.edu ** E-mail: vatalaro@ing.uniroma2.it yy E-mail: maryan@tsc.uc3m.es