Work

Theoretical foundations of waste factor and waste figure with applications to fixed wireless access and relay systems

Year: 2025

Type: article

Abstract: The growing energy demands of next-generation wireless systems call for unified, system-level metrics to evaluate and optimize energy efficiency. This paper advances the concept of the Waste Factor (W), or Waste Figure (WF) in decibel scale, as a general framework for modeling power loss across cascaded communication components. By integrating W into the Consumption Factor (CF)–the ratio of data rate to consumed power–we reveal how component inefficiencies influence the minimum achievable energy per bit. Closed-form expressions are derived for energy-per-bit consumption in both direct and relay-assisted links, along with a decision rule for selecting the more energy-efficient path. While not explicitly modeled, Reflective Intelligent Surfaces (RIS) are shown to fit naturally within this framework. The analysis is further applied to a Fixed Wireless Access (FWA) scenario, where asymmetries in traffic direction and hardware inefficiencies are jointly considered, demonstrating the utility of the Waste Factor in guiding energy-aware system design.

Source: npj Wireless Technology

DOI: 10.1038/s44459-025-00001-2

Authors: Nurullah Sevim, Mostafa Ibrahim, Sabit Ekin, Theodore S. Rappaport

Institutions: Texas A&M University, New York University

Language: English

Topic: Advanced Wireless Communication Technologies

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Industry, innovation and infrastructure

Open Access status: diamond

Funders: U.S. Department of Energy, Office of Science, Hagler Institute for Advanced Study, Texas A&M University, Advanced Scientific Computing Research