A CDMA Satellite ISDN Modem ASIC

| Code Division Multiple Access (CDMA) promises to become an enabling technology for the future generation of satellite communication services. Spread-spectrum modems for satellite communication currently on the market are targeted towards voice and facsimile communications at rates up to 10 kb/s using transmission band-widths up to 5 MHz. However, emerging multi-media services such as videoconferencing, video-phones and internet access in remote areas require ISDN-compatible data rates and more simultaneous users than can be supported with the current generation of satellite modems. The Satellite ISDN-rate Modem Base-station ASIC (SIMBA) is a high-speed CDMA modem ASIC currently being investigated at IMEC's VSDM division. The aim of SIMBA is to simplify the design of CDMA satellite base-stations and user terminals with optimal cost/performance, by integrating a complete baseband spread-spectrum transceiver on a single die together with a general-purpose microprocessor core. SIMBA also serves as a case study for a system design methodology that facilitates the design of heterogeneous hardware/software systems-on-a-chip, linking the integration of highly optimised application speciic DSP blocks with state-of-the-art data converters, as well as commercially available macrocells such as the ARM7 embedded RISC controller and embedded memory blocks.