A GPS/Galileo SoC with adaptive in-band blocker cancellation in 65nm CMOS

Abstract

The proliferation of location-based applications inside various handheld electronic devices, such as mobile phones and internet tablets, demands the GPS system to have low power consumption, small form-factor and be co-located on the same device with other radio systems, such as cellular, BT, and WLAN. The conventional GPS solution often uses two SAW filters, before and after an external LNA, to meet the requirements of low noise and multi-radio coexistence. Nevertheless, it is highly desirable to remove the external LNA and interstage SAW filter due to size and cost, which presents a great design challenge to achieve high out-of-band linearity with very low power consumption. To fulfill these stringent requirements, a more comprehensive approach is needed to target a radio architecture with a proper RX system budgeting and optimal circuit design. In addition, a GPS system can be desensitized by unexpected in-band blockers generated from other subsystems on the same platform, such as LCD display, PMU, CPU system clocks, etc. The GPS digital baseband processor must possess the capability to withstand in-band blockers without significant performance degradation. This paper presents a GPS/Galileo SoC with an adaptive in-band blocker cancellation scheme, which is implemented in a 65nm CMOS process.