Quintplexers For Simultaneous-GPS Tri-Band Dual-Mode CDMA Handsets

Mobile handsets are used for more than just placing a phone call; they are now multimedia systems which can take photos, surf the web, send email, and play video, games or music. Adding this functionality results in less space for the radio front end, which itself is moving towards more complex multi-band/multi-mode operation. In the last few years, multiple blocks of filters/duplexers (a.k.a. multiplexers) and power amplifier duplexer front-end modules and have widely appeared in CDMA handsets. Initially only available in high-end, feature-rich, low-volume handsets, these integrated modules are now steadily penetrating into lower-tier, higher-volume handsets. Each integrated solution brings its own unique performance value proposition, but all offer common size reduction and quicker time-to-market. Design cycles are shorter with integrated solutions because they can efficiently handle the interactions between discrete components and have fewer RF components to put together. Substantial PCB space reductions of up to 70% could be realized while routing and matching losses are reduced or eliminated improving performance. This article reports Avago Technologies' multiplexer solution for use in simultaneous GPS (S-GPS) phone applications and a discussion of what parameters were considered to be important for successful implementation.

Today's phones are required to comply with phase two of E911 FCC regulations which mandates the ability to determine the precise location (within 150 - 300 meters) of wireless callers in case of an emergency. This is typically accomplished one of two ways, either by radio triangulation between radio base station towers or by using a GPS (at 1575.42 MHz) device built into the phone itself. GSM/TDMA network operators, such as AT&T and T-Mobile, tend to use the triangulation method while CDMA network operators, such as Verizon and Sprint, tend to prefer to use the handset-based GPS method. CDMA market penetration has been supported by Qualcomm's integration of GPS into its baseband products. High-end WCDMA phones are beginning to adopt GPS with an estimated 50 million GPS-enabled units to be sold by the end of 2008. In 2006, 11% of worldwide handsets sold had GPS functionality (108 million) with totals expected to rise to 30% (386 million) by 2011. Location based services such as mobile social networking and mobile navigation are rapidly being rolled out by service providers to take advantage of the mandated GPS hardware.