Impulse Radio Ultra-Wide Band

IR-UWB is a wireless technology based on short duration pulses (on the order of few nanoseconds or even less) which has a big advantage compared to the other wireless technology populating our wireless spectrum.


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IR-UWB makes it possible to implement ultra-low-power and short range communication (see this link) and provides localization capability. These advantages are both related to the use of short duration pulses: they enable aggressively low duty cycling to decrease to fractions the power consumption of transmitters and receivers and time-of-flight estimation (ranging) from which indoor relative localization can be estimated. IR-UWB is a technology that can be effectively used in IoT through commercially available chipsets (e.g., Decawave, Time domain or Bespoon) or through application-specific research and development. A lot of work can still be done in the Research and Development context, in particular to enable additional features for the IoT (see this Eurotraining presentation here).

The research activity has started in 2010 in the former Center for Space Human Robotics (CSHR) IIT@PoliTo, in cooperation with the MINES group of the Politecnico di Torino.

Chip Gallery

ALL-DIGITAL 1-GBPS IR-UWB TRANSMITTER BASED ON MASTER-SLAVE PLL SYNTHESIS

The chip contains an impulse-radio ultrawideband transmitter (and a receiver) based on a double all-digital PLL pulse synthesis capable of synthesizing 250 ps pulses with both controlled center frequency and bandwidth using a single 31.25 MHz crystal reference. The transmitter, developed in cooperation with the IIT Neuroscience and Brain Technologies department (NBT, see here), is designed for applications in high density neural recording systems (up to 1024 electrodes). To generate timing references and packets the synthesizer core feeds also a logic interface operating at 250 MHz with four 1.2–3.3 V external parallel channels. The master–slave PLL combination achieves 5 pJ/pulse energy consumption and digital synthesis with −103 and −93 dBc/Hz at 1 and 4 GHz, respectively. The transmitter occupies 0.04 square millimiters area.

Related publication:

M. Crepaldi, G. N. Angotzi, A. Maviglia, F. Diotalevi and L. Berdondini, "A 5 pJ/pulse at 1-Gpps Pulsed Transmitter Based on Asynchronous Logic Master-Slave PLL Synthesis", in IEEE Transactions on Circuits and Systems I: Regular Papers, 2017.

ALL-DIGITAL SUB-GHZ IR-UWB TRANSMITTER BASED ON AN ASYNCHRONOUS LOGIC PLL

The chip contains an impulse-radio ultrawideband transmitter (TX) based on a ring oscillator capable of synthesizing pulses with both controlled center frequency and bandwidth using a single duty-cycling/trigger reference input. The TX embeds a single-phase charge-pump phase-locked loop (PLL), implemented with asynchronous logic, with 55 logic elements overall. The system, including radio frequency output buffers, consumes measured 30-45 pJ/pulse with a measured efficiency of ~ 47% at 285 MHz center frequency and Vdd in the range of 0.97-1.17 V.

Related publication:

Crepaldi, M.; Demarchi, D., “A 130-nm CMOS 0.007- Ring-Oscillator-Based Self-Calibrating IR-UWB Transmitter Using an Asynchronous Logic Duty-Cycled PLL,” IEEE Transactions on Circuits and Systems II: Express Briefs, vol.60, no.5, pp.237-241, May 2013.

AN ULTRA-LOW POWER PULSED DIGITAL RADIO BASED ON LOGIC CELLS

The chip is an ultra-low-power radio receiver implemented only with CMOS logic gates used as basic building blocks and proves its operation. The self-timed duty-cycled system is self-synchronized with the input radio signal, runs a noise-robust baseband detection and does not require any reference besides power supply. Based on S-OOK modulation, the 350-450 MHz digitalradio RX occupies an area of 0.07 mm 2 in a 130 nm RFCMOS technology and achieves a 0.1% sensitivity of -63 dBm at 95 kbps, 380 MHz center frequency and 40 μW active power consumption at 1.1 V power supply. At 1.0 V it achieves -62 dBm sensitivity and 33 μW active power at ~ 0.1% error rate.

Related publication:

Crepaldi, M.; Macis, S.; Ros, P.M.; Demarchi, D., “A 0.07 mm Asynchronous Logic CMOS Pulsed Receiver Based on Radio Events Self-Synchronization,” IEEE Transactions on Circuits and Systems I: Regular Papers, vol.61, no.3, pp.750-763, March 2014.

ALL-DIGITAL AND ULTRA MINIATURIZED UWB TRANSMITTER

This chip is a very low-complexity all-digital IR-UWB transmitter that can generate pulses in the band 0-5 GHz, requiring a silicon area lower than a PAD for signal I/O. The transmitter, suited to non-standardized low data rate applications, is prototyped in a 130 nm RFCMOS technology and includes analog control signals for frequency and bandwidth tuning. Center frequency is linearly selected with voltage supply, 0.5 V for the range 0-960 MHz and 1.1 V supply for the higher 3.1-5GHz range. The architecture is based on the same delay cell for both baseband and radio frequency signal generation and pulses fractional bandwidth remains constant when voltage supply and control voltages scale. At 420 MHz center frequency, the transmitter achieves 7 pJ/pulse, and for 4 GHzcenter frequency pulses, it achieves 32 pJ/pulse active energy consumption. The OOK/S-OOKtransmitter occupies an area of 0.004 mm2.

Related publication:

Crepaldi, M.; Dapra, D.; Bonanno, A.; Aulika, I.; Demarchi, D.; Civera, P., “A Very Low-Complexity 0.3–4.4 GHz 0.004 mm All-Digital Ultra-Wide-Band Pulsed Transmitter for Energy Detection Receivers,” IEEE Transactions on Circuits and Systems I: Regular Papers, vol.59, no.10, pp.2443-2455, Oct. 2012.

ASYNCHRONOUS AND EVENT DRIVEN IR-UWB RECEIVER FOR VERY HIGH SENSITIVITY SHORT DISTANCE ESTIMATION

This circuit is a fully asynchronous threshold-based IR-UWB receiver which enables a high sensitivedistance estimation. It includes an ultra-low power baseband unit which achieves 533 fJ/pulse with an asynchronous, multipath robust and time expiring energy detector, which embeds signal strength in the baseband processing latency to increase sensitivity to TX-RX separation. Asynchronous line-of-sight over-the-air measurements obtained with an integrated all-digital transmitter show a maximum sensitivity of 1mm TX-RX separation per nanosecond system latency. The RX also permits data communication based on the use of self-synchronized modulations.

Related publication:

Crepaldi, M.; Ros, P.M.; Bonanno, A.; Morello, M.; Demarchi, D., “A non-coherent IR-UWB receiver for high sensitivity short distance estimation,” 2014 IEEE International Symposium on Circuits and Systems (ISCAS), vol., no., pp.1905,1908, 1-5 June 2014.

Radio Systems

ULTRA-LOW POWER AUDIO STREAMING SYSTEM BASED ON NON-COHERENT IR-UWB

This system has been specifically developed to overcome the power consumption limitations occurring with Bluetooth audio streaming (A2DP). Thanks to the use of an analog pulse-frequency modulation (PFM) based on the radiation of short duration pulses, and an ad-hoc designed IC hardware to enable the asynchronous reception of pulse events, significant savings compared to Bluetooth can be obtained without using Codecs. The prototype system operates operates with a single channel (mono) and at the transmitter side it can achieve 10 hours operation. The system is based on a full-custom IC and commercial components, to which at least 60% of the power consumption can be imputed.

Related publication:

Crepaldi, M.; Stoppa, M.; Motto Ros, P.; and Demarchi, D., "An Analog-Mode Impulse Radio System for Ultra-Low Power Short-Range Audio Streaming," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 62, no. 12, pp. 2886-2897, Dec. 2015.

ISCAS 2015 Poster