Purposeful Co-Design of OFDM Signals for Ranging and Communications

TL;DR

This paper investigates the fundamental trade-offs in designing OFDM signals for simultaneous ranging and communication, providing bounds and strategies for optimal pilot resource allocation under various channel conditions.

Contribution

It introduces a comprehensive analysis of the trade-offs in OFDM co-design for ranging and communications, deriving bounds and proposing Pareto-optimal resource allocation strategies.

Findings

Bounds on capacity and ranging variance are derived for frequency-selective fading.

Pareto-optimal design strategies depend on channel conditions.

Impact of channel knowledge and phase errors on bounds is quantified.

Abstract

This paper analyzes the fundamental trade-offs that occur in the co-design of pilot resource allocations in orthogonal frequency-division multiplexing signals for both ranging (via time-of-arrival estimation) and communications. These trade-offs are quantified through the Shannon capacity bound, probability of outage, and the Ziv-Zakai bound on range estimation variance. Bounds are derived for signals experiencing frequency-selective Rayleigh block fading, accounting for the impact of limited channel knowledge and multi-antenna reception. Uncompensated carrier frequency offset and phase errors are also factored into the capacity bounds. Analysis based on the derived bounds demonstrates how Pareto-optimal design choices can be made to optimize the communication throughput, probability of outage, and ranging variance. Different pilot resource allocation strategies are then analyzed, showing how Pareto-optimal design choices change depending on the channel.