Where are we going from here?


by wirelesh — 7:40 PM on May 11, 2008

How can we make voice communications available to rural communities in mountainous regions of the developing world? I have been searching out answers to this question for almost two years now. For the past several months I have been researching and blogging about some of the technological aspects, focusing specifically on long-distance WiFi to determine the feasibility and cost involved and what resources are required. I have yet to research other technologies which I expect are needed, such as VoIP, bridging with existing telephone systems, wireless mesh networking, power systems, and building towers. In the next couple years I will dig into these aspects and hope to implement my research and experiences.

Options: the improbable and the possible

Following are several technologies that have been considered for developing regions, with some of their drawbacks noted.

  • Obviously the mature and well-known option for voice communication in most of the world is cellular telephone technology. However, cellular coverage is largely limited to urban areas, especially in the developing world. As Intel researchers state it (PDF), "existing infrastructure that is useful in high-density areas, where costs can be spread over many users (notably, cellular telephony), is not appropriate for sparsely populated rural regions." For example, the coverage map for Mali, Africa shows nine small pockets where cell phone service is available. The village of Gono, Mali receives coverage primarily because they happen to be close to an urban center. Nevertheless, this story is an example of how rural areas greatly value communications and are often willing to pay for it.
  • Satellite connectivity offers opportunities for rural areas, and a number of mobile satellite-based solutions exist such as satellite telephone and R-BGAN. However, these incur heavy per-minute charges.
  • Using VoIP over a satellite Internet (VSAT) connection is more realistic, but set up and monthly charges are high, and latency (packet delay) makes the voice quality less than desirable.
  • Laying underground fiber optic cable is prohibitively expensive.
  • HF, VHF, and UHF radios require special licensing and are by their nature one-to-many.

The solution I have decided to pursue is a combination of long-distance WiFi, VoIP, and mesh networking. I am not alone in thinking that economical WiFi solutions exist. Organizations such as Green WiFi and Inveneo have invested in this idea, as well as projects like AirJaldi, Nepal Wireless Networking Project, Africa Mpumulanga Mesh, Freifunk, Wireless Networking in the Developing World, and TIER (UC Berkeley) working together with Intel. While consumer-grade WiFi systems may not have the reliability, bandwidth, and quality of service generally expected by cellular service providers, communities with zero voice communication options have much lower expectations, and there are several significant advantages over traditional cellular:

  • Consumer WiFi equipment is readily available and inexpensive because it is so widely used across the world.
  • WiFi equipment usually has low power requirements, which means towers can be solar-powered and not require generators and/or connection to the power grid. As a consequence, initial capital investment and maintenance can be dramatically lower, and no pre-existing wired infrastructure is necessary.
  • WiFi (2.4 GHz, 5 GHz) and other ISM frequencies which are unlicensed in western countries are often also unlicensed in developing countries, so government licensing fees can be dramatically lower.

Testing and lessons learned

During my time in the U.S., I set out to build a mini prototype network which included three nodes, two of which would be over 100 km (60 miles) apart, a VoIP server, and telephones so that I could test every aspect of the network which I envisioned. My first mistake was being overly optimistic, (something I'm good at in other areas as well); I was able to test only a fraction of the planned prototype network. I had planned on using exclusively Linksys routers because they are familiar to me, inexpensive, and ubiquitous. However, as I began researching software and hardware and making purchases, I discovered that, as Yahel Ben-David (of AirJaldi) expressed it, "[Linksys devices] are not advisable for that task. Too little power and worse - it uses a Broadcom radio for which we can't do many of the things we do for Atheros-based radios." This was my biggest course change, and effected many other aspects of the network I ended up testing. However, I am so thankful that I made this change before going up on the mountain.

Thanks primarily to comments made in this blog, the second most important thing I learned involved dealing with snow and ice when installing antennas on mountains. I had the expectation that these grid-type parabolic antennas would do fine in all weather conditions, but I learned (the easy way) that a radome or shelter of some sort is essential. All my testing was well worth it, although the job was a lot longer and harder than I expected. My biggest disappointment was that the 121 km (75 mile) link only achieved about 585 Kb/s throughput--plenty for a good number of VoIP phone calls, but I was hoping for several times more. Also disappointing was the fact that the 23 km link never worked as planned, and that I could not test VoIP at all over the long-distance link. Since the January testing, Intel made an exciting announcement about a router capable of greater than 6 Mb/s over 100 km. Although it is not mentioned in the article, Intel has been partnering with the UC Berkeley TIER group to design the software for this router--the very software I used in my 121 km test.

Going forward

Technology alone is not sufficient. For any project like this to work for more than a couple of years, it must have a sustainable business model. (In the long run, at least as much money needs to come in as is going out.) Village Phone, which builds on traditional cell phone technology, has been very successful in bringing communications to rural Africa. Their model, in summary, involves an entrepreneur from the village purchasing a cell phone, roof antenna, and charger with the help of a microloan. They are then able to sell minutes to villagers for a profit. The cell phone antenna must be within about 35 km of a cell phone tower and have line of sight, thus making the technological aspect of this model unworkable in many rural or mountainous regions. The business model, however, could potentially be used just as successfully with other technologies, including WiFi paired with VoIP. This area will require much more research--learning about small businesses, understanding local culture, and relating to local and national governments.

In all of this, I would love your input. I really appreciate and have gleaned a lot from the people who have taken the time to write, both in personal emails and in the blog comments. I have worked with computers for over twenty years, but my experience in most of the other areas is quite limited. With your help, this project has a much higher probability of success.

   
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