Wireless Grids

By Roland Piquepaille

A new concept is emerging in networking: wireless grids. These grids connect all kinds of wireless devices, such as sensors or cell phones, with each other and with more traditional wired grids. IEEE Internet Computing has devoted a very long and thorough article about these wireless grids which can deliver new resources, locations of use, and institutional ownership and control patterns for grid computing via ad hoc distributed resource sharing. The article says that applications for wireless grids fall into three classes: the ones which aggregate information from the range of input/output interfaces found in nomadic devices, those which focus on the locations and contexts in which the devices exist, and those that leverage the mesh network capabilities of collections of nomadic devices. The authors add that these grids "emerged from a combination of the proliferation of new spectrum market business models, innovative technologies deployed in diverse wireless networks, and three related computing paradigms: grid computing, P2P computing, and Web services."

The first question to ask is what is new with this kind of networks.

Wireless devices bring new resources to distributed computing. In addition to typical computational resources such as processor power, disk space, and applications, wireless devices increasingly employ cameras, microphones, GPS receivers, and accelerometers, as well as an assortment of network interfaces (cell, radio, Wi-Fi, and Bluetooth). One important class of devices is sensors, which can supply information on temperature, health, or pollution levels, to name just a few.

People increasingly take wireless devices with them to new places, in both their personal and professional lives. The numbers of those devices that include sensors are growing. In fact, the pervasive mobile phone is developing into a super-sensor. From shopping malls to medical disaster areas, sporting events, and warehouse floors, wireless devices -- and the sensors in them -- are on the verge of becoming ubiquitous. Wireless grids present an opportunity to leverage available resources by enabling sharing between wireless and nonwireless resources.

The authors also put wireless grids in context.

Wired grids are typically aggregations of fixed resources between known institutions, be they academic or corporate, in high-trust and relatively static environments. Fixed wireless grids borrow from the wired grid model. To participate in the Grid using the current Globus software, for example, a machine must create and preregister an X.509 certificate. These static, trusted environments stand in stark contrast to the situation facing the wireless grid.

The wireless grid thus draws on at least three of the computing paradigms currently undergoing rapid development. The illustration above places wireless grids in context, illustrating how they span the technical approaches and issues of Web services, grid computing, P2P systems, mobile commerce, ad hoc networking, and spectrum management. How sensor and mesh networks will ultimately interact with software radio and other technologies to solve wireless grid problems requires a great deal of further research. (Credit for image and legend: IEEE Internet Computing)

The authors also look at the Wireless Grid Infrastructure, The Economics of Wireless Grids and some applications under development.

Finally, they try to guess the future of wireless grids.

The emergence of wireless grids parallels the historical trend that has seen computing shift from a hierarchical structure -- in which computing was an organizationally controlled activity -- to a situation in which the only guarantee is that individual users will follow their strategic interests. The initial developers of grid computing applications and architectures naturally focused on applications deployable within and across hierarchically controlled organizations such as super­computing centers.

Application developers have an opportunity to draw on the new resources, interfaces, and locations that wireless devices provide. We have sketched the abstract requirements for ad hoc resource sharing and described a modest demonstration application. An abundance of research challenges remain in crafting engineering applications and appropriate radio technologies, as well as developing reliable clearing mechanisms and spectrum policy.

If you're interested in the future of networks, this article is not only a must-read, but you need to keep it for the all the references it offers.

On the related subject of wireless mesh networking, you also should read this article from EE Times, "Futuristic factories make mesh." Here are the two opening paragraphs.

It is the holy grail of the factory floor: hundreds of sensors wirelessly connected, monitoring motors for problems and drastically reducing energy consumption -- all with the precision and rhythm of a philharmonic orchestra.

The need is there, the software is there, the topology is fairly well understood and the silicon costs are falling. One market forecaster sees 169 million nodes and a $5.9 billion end-user market by 2010. Still, it's not as easy as it looks. Wireless mesh is a new paradigm with lingering unknowns, and some wireless silicon is still more expensive than wired solutions. The goal, in the eyes of many, remains a ways off.

Source: Lee W. McKnight and James Howison, Syracuse University, Scott Bradner, Harvard University, for the July/August 2004 issue of IEEE Internet Computing; R. Colin Johnson, EE Times, August 9, 2004