- Wireless Building Blocks
- Wireless Decision Process
- From Business Requirements to Technical Requirements
- Moving from Requirements to Design
- Working Around Wireless Constraints
- Example Solutions
5.5 Working Around Wireless Constraints
As you translate your business requirements into technical specifications, you will undoubtedly discover that the wireless environment is rife with constraints, incompatibilities, and compromises. You may discover that your original solution cannot be deployed as envisioned as limitations in areas such as wireless network bandwidth and device displays reintroduce constraints that have long been eliminated in the world of wired workstations. Don't let these issues push you into abandoning or unnecessarily delaying your foray into wireless technology. Although wireless technology has yet to reach the levels of maturity, standardization, and support found in other information technologies, corporations such as FedEx and UPS have used wireless solutions productively for years. Current wireless capabilities are sufficient to handle many practical applications, and wireless constraints can often be overcome through creative design. There are two principle categories of wireless constraints.
Evolving Constraints Some wireless constraints are temporary. Over time, the rapid evolution of wireless capabilities will reduce constraints in areas such as standards, bandwidth, coverage, security, and support tools. For example, the throughput of short and wide area wireless networks continues to improve, and the arrival of 2.5G and 3G networks will provide high-speed data exchange across a wide geographic area. Similarly, coverage is improving as wireless network operators continue to add infrastructure.
Inherent Constraints Other constraints such as device size, display limitations, and data entry capabilities, result from the demand for small, portable devices and are a permanent part of the wireless landscape. A typical mobile device will never support the robust applications found on a desktop. Display size and resolution determine the volume and type of information that can be presented effectively. Keyboard size or handwriting recognition schemes direct the types of interactions possible. Memory and processing power affect the architecture of the application. Size, weight, and useful battery life affect the portability and convenience of the device. These inherent constraints must be overcome by designing around them. For example, applications can use numbered menus or forms to minimize data entry, and intelligent partitioning of functionality between the device and an application server can circumvent processing and memory constraints.
There are many possible paths to take when designing a wireless solution. If the original solution is blocked by limitations, another approach or combination of approaches may give you the capabilities you need.
5.5.1 Rethink Constraints
Is the perceived constraint truly a limitation or is it imposed arbitrarily? A given solution may require sending forms between the user and a corporate system. If the entire form is sent on each transmission, the bandwidth of a wireless wide area network may be insufficient. If the application is designed to transmit only the changed portions, however, current bandwidth may be more than adequate. Does a traveling salesperson really need instant access to account file updates or can files be updated once a day? System architects and designers used to working on unconstrained wired office systems may need to rethink their approach to solution design to work around, or even take advantage of, the differences in wireless capabilities.
5.5.2 Switch Paths
Ask yourself if you can accomplish the same goals with a different set of technology options. For example, if your main goal is to relay sales orders to your corporate office, you may enter the information through a wireless web page, use a custom designed form to transmit data across a digital cellular network, or use e-mail templates through an e-mail device. While the form of the data and the design of the application may be very different, the end result is the samethe sales order is relayed.
5.5.3 Reprioritize Features
While the originally intended, fully featured content-rich solution would have met every need of your target audience, you may be able to gain most of the solution's benefits using a less ambitious design. As described in the Chapter 3 case study, Atlantic Envelope Company found that a small set of capabilities covered a very large percentage of their sales force automation needs. Focusing on the top ten customer queries, allowed the company to develop, deploy, and gain benefits from their solution now, using currently available and easy to implement technology.
5.5.4 Find Creative Workarounds
Look for creative workarounds if particular aspects or functions of your solution run into roadblocks. As an example, in an originally envisioned medical solution, emergency room doctors would have received an updated version of the emergency room's patient whiteboard on demand. Experience quickly showed, however, that the busy and highly mobile physicians could not tolerate having to initiate and wait for the updated whiteboard to load on their handheld devices. To overcome this issue, the project's design team switched to a "push" approach, automatically relaying updates once a minute to the doctors' devices. By restricting transmissions to only those items that had changed, transmissions were kept short and unobtrusive, enabling the doctors to simply look at their devices periodically to see up-to-date whiteboard contents.
5.5.5 Break the Problem into Smaller Parts
Sometimes a combination of approaches provides a more effective solution than a single approach. Penske Logistics uses wireless technology on its trucks and at its cross docks to keep customers informed about deliveries and manage driver routes and performance. An onboard computer manages and transmits data about arrival and departure times, delays, traffic conditions, and changes in schedules in near real time over a satellite network. More routine data about cargo pickups and drop-offs is captured via handheld devices used by delivery personnel. When a truck returns to a Penske terminal, the routine data on the handheld device is synchronized with the host system via a wired docking cradle. This hybrid approach provides immediate exchange of high-value information, with coverage across Penske's entire delivery range, with periodic bulk transfer of less time-dependent data at much lower network costs.
5.5.6 Phase Your Solution
If your solution is constrained by limitations in evolving areas, such as coverage or bandwidth, you can use a phased approach to implement a subset of features now and add new features as limitations disappear. For example, you can provide field service workers with a mobile solution for dispatch and work order invoicing with current technology and add capabilities, such as access to on-line repair manuals or videos of repairs in action, as network capacities increase.