Carlos Rey-Moreno

Experiences, challenges and lessons from rolling out a rural WiFi mesh network

The computing for development community knows that technology interventions involve consideration of social, technical and environmental factors. Research into WiFi solutions has fallen off as ubiquitous mobile solutions penetrate even the deepest rural communities worldwide. This paper argues that the latest wave of WiFi mesh networks offers benefits that traditional top-down WiFi and mobile networks do not. In addition, we propose ethnographic and participatory methods to aid the effective rollout of mesh inverse infrastructure with and for a given community. This paper describes and then analyzes a mesh for voice rollout within a situated context. We explain how to conduct informed community co-design and how to factor in local socio-political concerns that can impact on the design, rollout and subsequent maintenance of community-based wireless mesh networks. While we have not yet analyzed baseline and initial usage data, we do have new lessons to offer.

A telemedicine WiFi network optimized for long distances in the Amazonian jungle of Peru

Isolated rural areas of developing countries often lack of any kind of communications infrastructure. There are some WiFi for Long Distances (WiLD) networks that have been deployed successfully in forests and mountainous regions of countries such as India, Colombia and Peru, for providing Voice over IP and Internet support to health centers. In this work a real telemedicine WiFi network deployed in the Amazonian jungle of Peru is introduced. Technical and social considerations taken into account and devices used for its deployment in such a difficult context are described together with the services provided. Furthermore, performance of this multihop network is analyzed in order to provide a better insight of its behavior. As a conclusion, we describe future and present works related to the improvement of the network.

Making a community network legal within the South African regulatory framework

Community networks often operate at the fringe of legality with respect to spectrum, network infrastructure and providing services. We have been involved with such a network in a rural community, and together with them, have devised a way to become legal within the South African regulatory framework. A not-for-profit co-operative was formed and successfully applied for license exemption to operate the network infrastructure and offer services. Revenue is used to sustain the network and can also be used for other community needs. The network has equipment that is not 100% type-approved, and operates at a higher output power than is allowed. However, we have a simple plan to comply with such regulations. This paper offers our experience as a precedent for how to go about making a community network completely legal in South Africa and other countries that have a similar regulatory environment.

Co-designing a Billing System for Voice Services in RuralSouth Africa: Lessons Learned

Access to information and communication technologies remains unaffordable for many in rural areas despite recent progress in providing voice services to remote communities. The sustainability of alternative technical solutions is a challenge, which can be addressed when local knowledge is taken into account during the design process. This research reflects on the process of co-designing a billing system for voice services provided by a Community Network in rural South Africa. Several payment methods were explored with users and operators of the Community Network, focusing on the legal, financial, technical and social feasibility - as well as constraints - of each method. Those methods that suited the communitys needs were implemented and tested with stakeholders. The process revealed factors embedded in the provision of voice services by traditional voice operators in South Africa that prevent economically poor and illiterate users from fully benefiting from voice services. Solutions to these factors were explored with users and were implemented as a billing system. The system is currently being deployed in a rural South African community. Both the problems experienced and solutions proposed may inform similar initiatives.

An in-depth study of the ICT ecosystem in a South African rural community: unveiling expenditure and communication patterns

There is no doubt of the contributions made by mobile phones and mobile network operators in increasing access to communications in rural areas of developing countries. Yet how affordable is this ubiquitous access in such an ICT ecosystem? Using data from two stratified random surveys conducted in a South African rural community, this paper provides a unique in-depth picture of the expenditure and communication patterns of its dwellers. Results show a high access ratio of people using mobile phone services weekly and a high proportion of disposable income dedicated to a very constrained set of mobile phone services. Factors such as mobile phone charging and the extra charges added by airtime resellers contribute to increase the communication costs. This data and its analysis can be used by the following: regulators and government agencies to better design their policy implementations to provide universal service and access; competing industry players to understand the dynamics within rural communities to better target their products; civil society organizations to use it as a case in their efforts to make affordable communications a constitutional right.

Community-based solar power revenue alternative to improve sustainability of a rural wireless mesh network

Given needs for a clean and easy way to maintain and secure powering rural wireless networks and to generate revenue to guarantee the sustainability of its intended goals, an approach to leverage solar power to address both needs simultaneously is presented herein. Results comprise empowered locals trained to ensure local maintenance and appropriation; local usage and maintenance data; and a costing of the solution and its maintenance after a year of operation. It is shown that the solution presented can be locally maintained and provide additional revenue for a rural wireless network to continue providing intended communication goals.

Asymptotically Optimal Cross-Layer Schemes for Relay Networks with Short-Term and Long-Term Constraints

Convex optimization and dual decomposition have been successfully used to design cross-layer resource allocation algorithms for cellular access networks. However, less effort has been devoted to design optimal algorithms for systems equipped with relay stations. Presence of relay stations renders the design of the access schemes more difficult and requires consideration of additional constraints. The present paper relies on a sum-utility constrained maximization framework to design cross-layer algorithms that guarantee diverse quality of service (QoS) and consider different forwarding strategies at the relay stations. One of the main challenges in the design is the joint consideration of both long-term (elastic) and short-term (real-time) constraints. Such constraints account for diverse delay QoS requirements and relay forwarding strategies. A two-step methodology is proposed to efficiently deal with this challenge. Specifically, for each time instant it applies: a) an approximate online method to estimate the multipliers for the long-term constraints and the corresponding primal variables (resources), and b) a classical iterative method to calculate the multipliers for the short-term constraints and the corresponding primal variables. Our approach incurs an arbitrarily small loss of optimality, and can accommodate both static and fading channels.

WiMAX-An Uncertain Promise for Bridging the Digital Divide

In general terms, technology is born as the indirect consequence of social demands that are identified by researchers as interesting problems to solve; in solving the problem, they produce new knowledge. If they think they will obtain benefits, manufacturers and service providers take those results and produce products and services that satisfy that demand. Undoubtedly, there exist social needs that cannot be covered while obtaining benefit. If a society considers covering those needs to be a social priority, then complementary measurements should be taken to adequately promote innovation.

Investigating battery consumption in low-end smartphones: Preliminary results

Due to lack of electricity in the rural communities of Africa, users often have to incur extra expense on recharging their mobile phones. The limited battery capacities of low-end smartphones, therefore, present a barrier to their positive integration with such communities because of their vast networking features that likely lead to their elevated usage, thus, causing faster battery depletion and in turn, escalating recharge costs. This paper presents preliminary results of ongoing investigations on battery consumptions in low-end smartphones in order to estimate their battery life under different usage scenarios, and estimate the surge in communication expense brought about from the frequent recharging. Voice call experiments over WiFi and 3G data, in different network mode combinations, were conducted using three brands of low-end smartphones. Results, compared using analysis of variance and Tukey methods for pairwise comparison, yielded Smart4Mini brand to be the least battery draining, along with Smart Kicka being second best and Galaxy Pocket Neo being least efficient. In addition, the investigations aided in building a platform for future experiments in order to precisely estimate communication costs under different usage scenarios. Dissemination of such information can assist rural users in making well-informed communication expenditure towards purchase and usage of low-end smartphones.

Tuning a mid-range rural WiFi-based mesh network

Little is known about how mid-range, or several km, distances affect multipoint-to-multipoint links when single radio nodes with omnidirectional antennas are used. In this poster, a real network with these characteristics is described and empirical results of its performance are presented. In particular, the effect of increasing the SlotTime value for optimizing the aggregated throughput has been analyzed. Results show the need to increase the SlotTime to considerably bigger values than those oberved for point-to-point and point-to-multipoint long-range links. With the new value of SlotTime, an increase of 115% in aggregated throughput was obtained over the standard Slottime value.