Ubiquitous Silicon

Each of these events has had a profound impact on the semiconductor industry. The mainframe, mini computer, PC and consumer handhelds have all been major drivers. We now see stabilization in semiconductor demand generated by the PC, while the demand generated by handhelds continues to grow.

We are all talking about the next big driver for semiconductor demand beyond the handhelds. A good candidate is ubiquitous computing, where we take the system per person ratio beyond the handhelds to a point where each person might be interacting with hundreds of small, wireless networked systems (Figure ).

Mark Weiser at Xerox PARC (Palo Alto Research Center) first described ubiquitous computing in 1988: “We believe that people live through their practices and tacit knowledge so that the most powerful things are those that are effectively invisible in use. This is a challenge that affects all of computer science. Our preliminary approach: Activate the world. Provide hundreds of wireless computing devices per person per office, of all scales (from 1-in. displays to wall sized). This has required new work in operating systems, user interfaces, networks, wireless, displays and many other areas. We call our work 'ubiquitous computing.' This is different from PDAs, dynabooks or information at your fingertips. It is invisible, everywhere computing that does not live on a personal device of any sort, but is in the woodwork everywhere.”

Ubiquitous computing extends the trend of increasing the number of processors per individual.

Ubiquitous computing is the manifestation of the convergence of Moore's Law and Metcalfe's Law. Moore's Law effectively states that the number of transistors per unit area increases exponentially over time. Metcalfe's Law states that the value of the network increases exponentially with the number of connections. Ubiquitous computing allows mankind's exponentially growing appetite for transistors to continue. Instead of having all of the computing power in a handful of systems, however, the processors will be distributed over a large number of interconnected systems. In place of a billion transistors on a single desktop processor, there will be a couple of billion transistors spread out over processors in the desktop, laptop, handhelds, and ubiquitous devices and sensors.

There are already a large number of microcontrollers per person in such common items as alarm clocks, dishwashers, refrigerators and coffee makers. Currently, the microcontrollers exist in isolation, unable to communicate with one another. With ubiquitous computing, all of the small systems with microcontrollers will be networked and work intelligently with other sensors. Advancements in software, sensors and user interfaces will allow the system to interact with the user unobtrusively, inferring its intentions and taking action automatically.

The ideal IC that addresses the requirements for ubiquitous computing will combine different functionality into a single die. For example, the CPU, non-volatile memory, volatile memory and radio capabilities would be on a single chip. The challenge for the semiconductor industry is to integrate the disparate process flows into a single substrate. The alternative would be to develop efficient chip-level packaging technologies that combine multiple ICs produced using different technologies into a single module.

An example of semiconductors that address the needs of ubiquitous computing is ICs built to provide solutions for the ZigBee wireless networking standard. The ZigBee standard is built on top of the IEEE 802.15.4 wireless specification, and is designed for applications that require low data throughput (up to 250 kB/sec), short range (~70 m) and long battery life (~2 years). A number of major chip manufacturers are currently shipping ZigBee chips, including STMicroelectronics (Geneva, Switzerland), Freescale (Austin, Texas) and Austin-based Chipcon (recently acquired by TI). While the demand for the ZigBee chips is currently relatively small, analysts expect the market to surpass the billion dollar mark by 2010. By that time, the software and systems communities might be ready with the new paradigm of ubiquitous computing.