Ultra-low-power UWB for sensor network applications

Abstract

Abstract-Long distance, low data-rate UWB communication for sensor network applications requires a highly energy efficient transceiver combined with circuit and system-level optimizations to maximize range. A custom pulsed-UWB transceiver chipset in 90nm CMOS is presented that targets these aggressive specifications. The transceiver efficiently communicates at data rates from 0-to-16.7Mbps in three 550MHz-wide channels in the 3.1 to 5GHz band by using pulse position modulation (PPM). The transmitter uses an all-digital architecture and calibration technique to synthesize pulses with programmable width and center frequency. The non-coherent receiver operates at 0.65V and performs channel selection filtering, energy detection, and bit-slicing. As FCC regulations limit the maximum transmit power of UWB communication, a run-length limiting technique is presented to reduce energy requirements when maximizing range at low data rates.

A 75 pJ/bit all-digital quadrature coherent IR-UWB transceiver in 0.18 µm CMOS

“…As explained in section II there are several IR-UWB architectures proposed in the literature with significant differences. When compared to low speed transceivers the circuit proposed in this work performs much better in terms of efficiency even whether they're coherent [2] or not [9]. When compared to medium to high speed IR-UWB transceivers it's clearly better than any other coherent systems [10] and only a non-coherent system such as the one presented in [1] has better energy per bit figures.…”

Ultra Wideband RF Transceiver Design in CMOS Technology

“…On the other hand, system throughput is limited by a high n. Therefore, high n is usually employed for low data rate systems where the goal is increased communication distance and improved BER. Pulse UWB can be categorized into carrier-based DS-UWB (Zheng, Y. et al, 2007(Zheng, Y. et al, , 2008 and carrier-less IR-UWB (Lee, H. et al, 2005;Zheng, Y. et al, 2006;Xie et al, 2006;Phan et al, 2007;Stoica et al, 2005;Mercier et al, 2008). In a carrier-based pulse UWB system, the baseband pulse is up-converted to RF pulse by a mixer at the transmitter side, and vice verse at the receiver side, therefore a power consuming local oscillator is needed.…”

“…In a carrier-based pulse UWB system, the baseband pulse is up-converted to RF pulse by a mixer at the transmitter side, and vice verse at the receiver side, therefore a power consuming local oscillator is needed. In a carrier-less UWB system, no local oscillator is needed, the transmitted signal is up-converted to RF band by performing differentiation on a Gaussian pulse; at the receiver side, the received pulse can be demodulated by down-sampling (Lee, H. et al, 2005), coherent (Zheng, Y. et al, 2006;Xie et al, 2006) or noncoherent (Phan et al, 2007;Stoica et al, 2005;Mercier et al, 2008) architectures. …”

A Fully Differential Digital CMOS UWB Pulse Generator

“…In the first one, a baseband signal of sufficiently large bandwidth is upconverted by mixing with a local oscillator whose frequency coincides with the central frequency of the desired UWB signal [15,21]. The second one attempts to generate a baseband signal that directly extends over the entire UWB range or a subband of it, using an analog approach [1][2][3]5] or a digital technique [7][8][9][10][11][12]. Our pulse generator belongs to this last category and is characterized by a new fully digital and differential architecture, conceived for a standard CMOS technology.…”

“…Unlike [7][8][9], and following an approach similar to [12,13,[15][16][17][18], our pulse generator emits UWB signals in 3.1-5 GHz, instead of the full 3.1-10.6 GHz bandwidth, in order to avoid interference with wireless local area networks (WLANs) in 5-6 GHz. Again, like in [11,13,18,22], we rely on a safe DLL-based technique in order to generate precise pulse durations, different from the approach suggested in [8,9,19] of using gate delays, which are imprecise and subject to high variability (a DLL was also used in [19] but with a different purpose). However, our work differs from [11,18,22] in that we generate a fully differential signal by using a symmetrical architecture which eliminates the DC component, and from [11,19,22] by providing a sound theoretical study about the pulse synthesis.…”