Defining a Wireless Solution
By Ian S. Hayes
This is an excerpt from the book, Just Enough Wireless Computing.
Turning a set of business requirements into a successful wireless solution is an exhilarating and challenging assignment. The technology is new and exciting, the results are very visible, and if the project is based on a strong business case, the impact on your company will be high. The most obvious parts of the exercise, such as selecting the type of wireless devices that will be deployed, have a "toy factor" appeal, making them appear fun and relatively straightforward. As you delve into the nuances of the selection, however, arriving at the right decision no longer seems so simple. The myriad options, issues, and considerations appear to grow exponentially. Worse yet, you will find that many of your desired choices are incompatible or require painful tradeoffs of functionality or features. From networks to devices to applications and implementation tools, there are simply too many complicated choices. Your seemingly straightforward solution has somehow turned into a jigsaw puzzle, composed of disparate pieces that must somehow fit into a complete picture. And, like a jigsaw puzzle, these pieces fit together only in a certain way. Put in one wrong piece and you won't be able to fit in the next right piece later. If approached in the wrong way, pulling together a complete wireless solution can be a daunting proposition even to experts.
Selecting the right components for a wireless solution requires navigating a complex and confusing maze of options and solution providers. The magnitude of capabilities, choices, and limitations of wireless components preclude the creation of a "one size fits all" wireless solution applicable to any business requirement. An architecture that works perfectly for one solution will be hopelessly inadequate for another. For example, the wireless solution used by American Airlines to track freight carts and dollies at the airports is vastly different from the one used by Fidelity Investments to allow investors to monitor stock prices and make trades.
Fortunately, a number of techniques can greatly simplify the conversion of business requirements into a well-defined wireless solution. Perhaps the most important trick is to reduce your range of options before becoming mired in the details of solution definition. Assembling a workable solution in a reasonable period of time is almost impossible if you must consider every potential device, network, application, and implementation option. The nature and constraints of your business requirements can be used to your advantage, however, to eliminate many of these options before you start, greatly reducing your research and evaluation efforts. For example, let's assume that we operate a food delivery service throughout the New England area and wish to provide our drivers with directions to drop-off locations and capabilities to accept on-site credit card payments for deliveries. As shown in Figure 5.1, these constraints significantly reduce our pool of options. We need only consider network options that support moderate data volumes from providers offering full coverage across New England. Short- and medium-range network options such as infrared, Bluetooth, and 802.11b don't apply, and the data volume requirements eliminate satellite networks. Since coverage varies by carrier, we'll have to pick a network service provider who covers New England. Similarly, our choice of devices is limited to those that can handle outdoor conditions, support credit card scanning, and work with our selected network. The implications of these decisions set parameters and refine options for other aspects of our solution. We have to choose (or develop) software that operates on the selected device; we need strong security to protect credit card information; and our training and support processes must be designed to fit this solution.
This chapter describes the process for turning business requirements into solution requirements. It uses the answers to the Why, Who, What, When, and Where questions from Chapter 4 to provide a framework for winnowing your wireless decisions into a manageable number. As shown in the example above, each business requirement imposes needs and constraints that create specific technical and operational requirements for the major components of our wireless solution. This chapter will explain how to develop specific requirements for devices, applications, data, and wireless networks. Comparing these requirements against the tables and other component-specific information in the second half of this book will enable you to quickly identify the wireless options that best apply to your needs.
Shrinking the Solution Spectrum