- Ubiquitous Computing
- Web Services
- The Semantic Web
- Spaces Computing
- Peer-to-Peer Computing
- Collaborative Computing
- Dependable Systems
- Pervasive Computing
- Cluster Concepts
- Distributed Agents
- Distributed Algorithms
- Distributed Databases
- Distributed Filesystems
- Distributed Media
- Distributed Storage
- Grid Computing
- Massively Parallel Systems
- Mobile and Wireless Computing
- Network Protocols
- Operating Systems
- Real-Time and Embedded Systems
Mobile and Wireless Computing
The mobile and wireless category of NDC is another broad field that encompasses technologies ranging from radio and television broadcasting to pagers, mobile phones, Bluetooth-enabled PDAs, and satellite communications. Even as the newest next-next-generation mobile phone hits the shelf, standards and protocols for that phone are being updated or even discarded. The fitscape is moving rapidly, as is the rapidly expanding wireless world that would serve wireless LANs.
Standards and Protocols
One driver is the acceptance of the WiFi standard. With Microsoft vocally committed to the standard, and companies like Sun Microsystems actively engaged in disseminating products that enable developers to bring applications to the space, wireless local networking for computers and other devices is spreading rapidly in many cities around the world.
Most wireless communications discussions split technologies into two general types: local and wide area. In time, these discussions will segment even further, as shown in Figure 3.9, ultimately reflecting a broader IEEE 802 vision:
Personal (wireless personal area network [WPAN]) local (within my clustered campus [LAN])
Wide (across townmetropolitan area network [MAN])
Very wide (across planet [WAN])
Figure 3.9. Taxonomy of wireless datacom (grouper.ieee.org/groups/802/)
The problems, opportunities, transmission frequencies, and data rates shift as we traverse the various ranges of wireless datacom.
Radio frequency identification (RFID) is a wireless protocol sponsored by AIM, the global trade association for the Automatic Identification and Data Capture (AIDC) industry. AIDC technology started tracking and access applications during the 1980s, providing for noncontact, low-bandwidth datacom. Effective in manufacturing and other hostile environments where barcode labels are not appropriate, RFID is established in a wide range of markets such as livestock identification and automated vehicle identification systems. RFID is found in "smart labels," which feature thin programmable stick-ons with a very small microchip and antenna to transmit product information. Tracking moving objects is a key feature of RFID. Incorporating RFID solutions into myriad ad hoc personal services will be inexpensive and easy as wireless LAN/MAN solutions provide integratable information fields.
Personal devices in years to come will include a bevy of connectables, including Internet-enabled eye-glasses with retinal projection systems, which will be linked with voice-activated input devices or hand-sized keyboards (innovative keyboard layouts will be necessary, perhaps a Nintendo-style input device, complementing voice-activated input devices). Such devices will also link with the simple wireless devices common today, such as automobile remotes, garage door openers, 900 MHz cordless phones, and wireless 802.11 networks. All of these devices operate within a short distance, typically just a few meters. Intelligent, integratable wearables that can sense "information fields" that will traverse the range of wireless datacom capabilities will become standardized, very likely around these and other protocols like Bluetooth.
Wide-area wireless devices operate over a much greater area, although many are similar to the more local wireless devices, which then touch global land-based support networks. Most mobile phones fall into this category. Other wider-area (somewhere between LAN and WAN) providers, such as Wave Wireless, are pioneering stationary, broadband-wireless solutions in 18+ GHz frequencies, using proprietary protocols. Solutions for remote broadband (short of satellite, which can be problematic if symmetric datacom services are required), these kinds of wireless solutions can provide point-to-point broad-band (11 Mbps and beyond) covering distances up to 40 kilometers.
But there's much more to wireless and mobile computing than datacom protocols and frequencies. Indeed, the preceding discussion might have been better suited to the network protocols category in any event. Application requirements are clearly different for mobile devices than for other general areas of NDC, so discussion of wireless and mobile platforms is also germane. Take the Java platform, for example.
The Java platform leads in wireless with the Java 2 Platform Micro Edition (J2ME), specifically designed for small or mobile devices. J2ME technology addresses a large number of intelligent consumer devices, ranging from pagers to set-top boxes. To address wireless and mobile needs, J2ME requires the mobile information device profile (MIDP), a set of Java APIs which when combined with the connected limited device configuration (CLDC) provides a complete J2ME application runtime environment. Targeting all types of mobile information devices, which generally have memory restrictions as well as tiny user displays and limited battery life, the MIDP/CLDC specifications address issues such as user interface, persistence storage, networking, and application model. J2ME through MIDP/CLDC provides a standard runtime environment that allows new applications and services to be dynamically deployed on the growing array of small, mobile devices, effectively enabling such devices to become intermittent nodes on the Internet.
Even As I Write . . .
The wireless fitscape is evolving at an incredible rate. The mobile and wireless category of NDC will have changed substantially by the time the ink is dry on these pages. Developments here also affect and are affected by a number of other fitscapes in the broad scope of NDC.