COMPUTING POWER IN MOBILE COMMUNICATIONS

Computing power can mean many things depending on where the term is applied. The computing power of today’s cellular handset is much greater than just ten years ago. The mobile phones of the 1980s used 8-bit microcontrollers with very little memory. A typical phone operated with 6 Kb of RAM (scratchpad memory) and 32 Kb of ROM (program memory).

That was fine, because AMPS was an analog communications system based on FM and the data rate was low because all data requires a modem to convert digital data to analog modulation. Data rates for wire-line modems in the early 1980s were initially 300 baud progressing to, at best, 19,200 baud by 1990. Therefore, rates of 1200 baud to 2400 baud were acceptable for wireless device communications. (One important point should be noted—gross baud rates and throughput are two different things entirely!)

The wireless cellular communications channel is a dirty, nasty place for data communications signals. Impairments to an analog cellular channel are noise, weak signals, interference, and signal dropouts caused by handoffs from one channel to another. Today’s digital cellular channel problems are compounded by signal degradation, multipath fading, and delay.

But today’s cellular phones have more computing power than the average workstation of the early 1990s. They will contain 16-bit, 32-bit, or 64-bit RISC microcontrollers, digital signal processors capable of 400 MIPS or more by 2002, and they will contain megabytes of memory. This translates to computational power sufficient to make a digital voice call or send highspeed data such as full motion video while simultaneously reading your email on the display. Data rates will soon approach ISDN or DSL rates and may go higher, anywhere from 114 Kbps to 2 Mbps or higher.

This vastly increased computing power (and the interest of the Defense Department) has brought one other very important new feature to wireless communications devices—Global Positioning Services (GPS). Using GPS, a wireless device can communicate its location to anywhere in the world. Orwell look out: Location-based marketing to a mobile customer base is coming.