IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY , VOL. 57, NO. 2, MARCH 2008 693 Measurement and Modeling of the Land Mobile Satellite Channel at Ku-Band Sandro Scalise, Member, IEEE , Harald Ernst, Member, IEEE , and Guy Harles Abstract—Thi s paper prese nts the res ults of a meas ure ment campai gn con duc ted in the winter of 2002 around the city of Munich in southern Germany. The primary goal was to evalu- ate the link performance of the land mobile satellite channel at Ku-band and to cha rac te riz e the tempor al behavior of the cha nne l to help in the evaluation of different fade mitigation techniques for fut ure mob ile sat ell ite sys te ms tha t aim at emp loying thi s frequency band. To achieve this objective, first- and second-order channel statistics will be presented, the outage probability of the channel analyzed, and a Markov-chain-based narrowband chan- nel model proposed. Index Terms —Ku-band, land mobile satellite channel (LMSC), radio prop agati on, sate llite mobile commu nicat ion, stat istic al modeling. I. I NTRODUCTION T HE USAGE of the Ku-band (10–12 GHz) in Europe is tradi tional ly mostl y limite d to stati onary services , and consequently, only a few publications on its usage for land mobile applications exist, such as [1] and [2]. Although satellite broadcasts in the Ku-band to fixed (television) receivers already has a successful history, today, L- and S-band dedicated high- power satellites are preferred for mobile satellite radio recep- tion (e.g., Worldsp ace, XM-Radio , and Sirius). One reason is that the use of Ku-band satell ite s req uires a hig her gai n directional antenna. In the mobile case, this obliges to develop termin als with satel lite tracking capabilit ies and hinders the possibility to employ satellite diversity technique as a coun- termeasure against channel fades, as done in XM-Radio and Sirius. The second drawback is the potential interference from neigh bor satellites. Nev erthe less, the relati vely high numbe r of exist ing Ku-ba nd tra nsp ond ers and the lar ge amount of av ailab le bandwidth prese nt an intere sting opportunit y that has rec ent ly att rac ted the interest of se ver al ope rat ors and researchers of the satellite communications field. Relevant ex- amples are the recently finalized studies to provide satellite- Manuscript received November 10, 2003; revised September 8, 2005 and January 13, 2006; accepted May 16, 2006. This work was supported, in part, by the European Space Agency as part of the European Space Research and Technology Center under Contract 15593/01/NL/DS. The review of this paper was coordinated by Dr. O. Ugweje. S. Scalise is with the German Aerospace Center (DLR), 82230 Wessling, Germany. H. Ernst was with the German Aerospace Center (DLR), 82230 Wessling, Germa ny. He is now with the Euro pean Space Agency (ESA), 2200 AG Noodwijk ZH, The Netherlands. G. Harle s is with Société Europée nne des Satel lites -Astr a (SES Astra), L-6815 Betzdorf, Luxembou rg. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TVT.2007.906338 based Internet and multimedia services to high-speed trains [3], [4], the hybrid Ku/Ka band system being developed in Korea [5] under the name of MoBISAT, and the satellite-based solu- tion to provide wireless Internet access onboard aircraft using Ku-band transponders (guaranteeing seamless connectivity also for intercontinental flights) that are currently being tested by the American company “Connexion by Boeing” on the first commercial flights [6]. Good knowledge of the behavior of the land mobile satellite cha nne l (LMSC) is of par amo unt importance to assess the per for mance of a future commun ica tio n system. The mai n effect in an LMSC is signal shadowing, which is experienced when no clear line-of-sight (LOS) between the satellite and the user terminal is present. The average duration and depth of this shadowing are key parameters that strongly depend on the environment in which the mobile user is located. Statistics of the LMSC based on measurements at L, S, Ka, and EHF bands and using the Markov-chain-based model, which was first proposed in [7], are present in the literature (see, e.g., [8] and [9]) and can be theoretically extended to Ku-band; but no model directly based on measurements in this band has been proposed so far. For this reason, a measurement campaign was performed within a feasibility study for a future Ku-band mobile sys tem, whi ch was commissioned by the Eur ope an Space Agency (ESA), to vali date the theor etical predic tions about channel behavior. The measurement setup will be described in Section II, and the considered scenarios will be presented in Section III. The statistical analysis of the measured data presented in Section IV will give an insight into the temporal behavior of the channel and the possible countermeasures to be devised to counteract its impai rment s. A parameter set for a Mark ov-chain- based channel model [7], [10] will also be presented. Finally, our conclusions will be drawn. II. MEASUREMENT CAMPAIGN SETUP The setup for the measurement campai gn is dep icted in Fig. 2. A test signal using horizontal polarization was trans- mitted by the geostationary satellite Astra, which is located at 19.2 ◦ E, and received by means of a low-gain 10 × 10 cm flat antenna with 19 dBi gain. The antenna and the low-noise block (LNB) were mounted on a mechanically steerable platform, which was placed on top of the DLR measurement van and covered with a plastic low-attenuation radome, as depicted in Fig. 1. The first intermediate frequency (IF) in L-band at the LNB output was downconverted to a second IF of 70 MHz and then 0018-9545 /$25.00 © 2008 IEEE
