Low power digital baseband architecture for wireless sensor nodes

Abstract

This thesis presents a digital baseband design for an upcoming wireless standards: IEEE 802.11ah. It is a branch of Wi-Fi (IEEE 802.11) standards. Compared with the previous Wi-Fi standards, this new standard has larger coverage range and consumes less energy. It is particularly suited for energy-constrained sensor applications. In contrast to the digital baseband of other Wi-Fi standards, this design consumes much less power: the power consumption of this Digital Baseband (DBB) is around 200 - 400 uW, which is hundreds times less than that of the traditional 802.11 baseband. The basic modulation method of the system is Orthogonal Frequency Division Multiplexing (OFDM) and the detailed algorithms are explored. To prove the robustness of the system, some error tests for the system are performed. A gate-level hardware design is also presented to prove the low-power design. Based on the synthesis results, a series of optimization is done to lower the power consumption. The DBB has been implemented in 40nm Low-power CMOS process to prove the concept. It includes the key blocks of this system. Measurement results show that the DBB for IEEE 802.11ah is suitable for low power applications.