Ingeniero

User-deployed and Capacity Evaluation of Multihop Wireless Networks: A Case Study for Nicaragua
Marvin S´ nchez G. a
Dept of Communication Systems, Royal Inst of Technology (KTH), Electrum 418, 164 40 Kista, Sweden. Email: marvins@radio.kth.se

Oscar Somarriba J.
Dept of Communication Systems, Royal Inst of Technology (KTH), Electrum 418, 164 40 Kista, Sweden. Email: oscars@radio.kth.seJens Zander
Dept of Communication Systems, Royal Inst of Technology (KTH), Electrum 418, 164 40 Kista, Sweden. Email: jens.zander@radio.kth.se

Abstract—In this paper we present a methodology for capacity evaluation of user-deployed multihop wireless networks in rural areas. The capacity is described by the maximum endto-end transmission rate (throughput) provided to each node that comprises thenetwork utilizing interference-based link scheduling. A user-deployed scenario for Internet access is studied utilizing 13 sites in rural communities located in the north center highland region of Nicaragua (telecenter candidates). To reduce the Internet service cost, shared common access points are used in mesh configuration under asymmetric traffic demands. The radio propagation environment isestimated utilizing the digital map GTOPO30 and the upper-bound capacity resulting from the user-deployed approach is reckoned by founding the link transmission schedule using nonlinear optimization. The results provide useful figure-of-merits and show that MWN is a feasible alternative to provide rural communication to those communities.

II. M ETHOD OF A NALYSIS The general research question ofinterest to be answered is: • What is the capacity that a user-deployed MWN can provide subject to low-cost deployment constraint for Internet access for the 13 community sites (telecenters)? For low-cost user-deployed scenario we consider the following: • Share Internet access: for low-cost Internet service (network service recurrent cost) nodes share access provider. • Economy of scale: we assumethe utilization of radio equipment parameters on the 2.4GHz frequency band. In Nicaragua, that frequency band is part of the allocated unlicensed radio spectrum subject to rules in AA001-2006 [2]. These rules are similar to the FCC part 15 in the USA. To share common Internet access points in a mesh configuration we assume asymmetric traffic demand from each node to a gateway node connected to theInternet and viceversa. The user-deployed scenario is analyzed estimating the radio propagation environment of located nodes. The path-losses in the network are derived utilizing the digital GTOPO30 (W100N40) [3] with the Longley-Rice model [4] as implemented by the Radio Mobile freeware program by VE2DBE [1].

I. I NTRODUCTION Nicaragua is a developing country located in Central America,composed by several urban and wide rural areas. In order to provide telecommunication services to the poorly covered areas in the countryside, the Nicaraguan government has social programs like FITEL, National Fund for Telecommunication Investment (by its acronym in Spanish), to provide access to telecommunication services in low-income and rural areas of the country. The rural communities of interestin this study have been provided by the regulatory body of Nicaragua, TELCOR, through the Project Coordination Unit (UCP). The UCP is an special unit that coordinates, proposes and evaluates project carried out through FITEL. The rural communities are located in the north central highlands region of the country, in the departments of Estel´, ı Madriz and Nueva Segovia. Fig. 1 shows the geographicallocations for the communities utilizing a digital map of the terrain. The paper is organized as follows: in section II we present the system models and methodology for the user-deployed multihop wireless network and the capacity evaluation method. The user-deployed approach and its results for the rural communities are presented in section III. The conclusions are presented in section IV....