RFIC's challenges for third-generation wireless systems

Third generation (3G) cellular wireless systems are envisioned to offer low cost, high-capacity mobile communications with data rates of up to 2 Mbit/s, with global roaming and advanced data services. Besides adding mobility to the internet, 3G systems will provide location-based services, as well as personalized information and entertainment. Low cost, high dynamic-range radios, both for base stations (BS) and for mobile stations (MS) are required to enable worldwide deployment of such networks. A receiver's reference sensitivity, intermodulation characteristics, and blocking characteristics, set by a wireless standard, define performance requirements of individual components of a receiver front end. Since base station handles multiple signals from various distances simultaneously, its radio specifications are significantly more demanding than those for mobile devices. While high level of integration has already been achieved for second generation hand-sets using low-cost silicon technologies, the cost and size reduction of base stations still remains a challenge and necessity. While silicon RFIC technology is steadily improving, it is still difficult to achieve noise figure (NF), linearity, and phase noise requirements with presently available devices. This paper will discuss base station specification for 2G (GSM) and 3G (UMTS) systems, as well as the feasibility of implementing base station radios in low-cost silicon processes.