LGIC Uses FLEX Devices to Pioneer Broadband CDMA WLL System
In the wireless world, the demand for advanced information services is growing. Voice and low-rate data services are insufficient in a world where high-speed Internet access is taken for granted. The trend is toward global information networks that offer flexible multimedia information services to users on demand, anywhere, anytime. The need to support bandwidth-intensive multimedia services places new and challenging demands on cellular systems and networks.
Evolving Standards Need Flexible Solutions
LG Information & Communications, Ltd. (LGIC) is the biggest supplier of code division multiple access (CDMA) infrastructure equipment to the largest cellular operator in Korea, and is one of the biggest handset suppliers to major operators such as Bell Atlantic Mobile, Airtouch, Sprint, and Telesp. In 1997, five companies-including LGIC-began developing a wideband CDMA (W-CDMA) modem for wireless local loop (WLL) service for Hanaro Telecom. Because the service standard was still under development, LGIC decided to use Altera FLEX® 10K devices to build their prototype system. The other four companies decided to use ASICs.
LGIC's initial prototype used four EPF10K100GC503-3 devices in each modem. Because of the modem complexity and because the standard was evolving, the engineers had to carefully fine-tune the design. Unfortunately, fine-tuning could not be tested with computer simulation; it had to be checked in-system. Because the Altera devices were reconfigurable, the LGIC designers could make changes quickly and see the results. In contrast, when the ASICs used by the competing companies began to have various problems, the ASICs had to be refabricated several times, wasting considerable time and money.
LGIC's second prototype had additional features and used EP10K100A and EPF10K250A devices for both the base station and the terminals. The operating clock frequency was more than 60 MHz, and the devices implemented key functions of the modem such as the searcher, finger, Viterbi decoder, combiner, and FIR filters.
"The device usage was mostly more than 90%, but we still managed to do a very good job," stated Kim Youn Hwan, a senior research design for LGIC. "It was really exciting that we did such a hard thing. Furthermore, because the MAX+PLUS II software had such good performance and was so easy to use, we didn't use any other third-party tools for VHDL synthesis."
In the Hanaro Telecom field tests, LGIC engineers used thousands of FLEX 10K devices. After successful field testing, LGIC built an ASIC to be used in the production system. Because of the performance and stability of the system, Hanaro Telecom chose LGIC as the provider of Korea's WLL systems and subscriber units.
Figure 1. Base Station Modem Prototype Board
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