What is UWB (Ultrawide Bandwidth)?

Ultrawide Bandwidth refers to a large channel bandwidth of 500 MHz, going up to 1.3 GHz. Its spectrum is from 3.1 to 10.6 GHz, and it operates at very low power (-41.3 dBm/MHz).

Why was UWB explored as a solution for fast and reliable communication?

According to Shannon's Formula, a channel's maximum capacity is proportional to its bandwidth. Therefore, UWB have a much higher capacity than other types of communication.

According to IEEE's work on Multi-band OFDM UWB, it can support data rates up to 480 Mbps with higher rates possible if combined with multi-level modulation schemes.

What were some of the challenges faced during this project?

Node Coordination using Half-Duplex Communication

The UWB module cannot send and receive data simultaneously, creating the need to coordinate nodes’ TX and RX phases. This half-duplex communication brings common wireless communication problems such as hidden or exposed terminal.

Our approach to this problem was to create a communication protocol that we felt suited our needs.

Speed vs. Reliability Tradeoff

Acknowledgements and retransmission improves reliability, however it adds overhead and decreases speed. Additionally, UWB technology has a relatively short range. This means the distance between nodes can affect data transmission speeds.

Robot Implementation

All UGV functionality needed to be individually implemented from the ground up. ROS is utilized on the UGV and remote station for efficient and low level data control.

What are other possible applications for UWB?

Accurate Location Data

The combination of ToF (Time of Flight) and PDOA (Phase Difference on Arrival) allows UWB to determine distance and direction of another module.

  • Real Time Location

  • Internet of Things

Security

The 802.15.4z uses HRP (High Repetition Pulse) and extends PHY/MAC preamble and coding options to allow more accurate location measurements.

  • real-time spatial context, accurate ranging and location leads to prevent eavesdropping and relay attacks

With UWB being extremely low power and high frequency, it is difficult for typical narrowband receivers to detect UWB communication. Also, the large frequency spectrum makes it robust to jamming.

External Links

For more information regarding some of the principles and technologies behind this project, we recommend visiting these resources.