# PhyCode: A Practical Wireless Communication System Exploiting Superimposed Signals

## TL;DR

PhyCode is a novel wireless communication system that dynamically exploits varying offsets among heterogeneous IoT devices to improve spectrum efficiency and decoding accuracy in superimposed signals.

## Contribution

It introduces a dynamic decoding scheme that leverages device-specific offsets, addressing limitations of prior static offset compensation methods.

## Key findings

- Achieves lower raw BER than existing methods
- Demonstrates effectiveness on software-defined radio platform
- Handles heterogeneous device offsets in dynamic environments

## Abstract

Superimposed signals are anticipated to improve wireless spectrum efficiency to support the ever-growing IoT applications. Implementing the superimposed signal demands on ideally aligned signals in both the time and frequency domains. Prior work applied an average carrier-frequency offset compensation to the superimposed signal under the assumptions of homogeneous devices and static environments. However, this will cause a significant signal distortion in practice when heterogeneous IoT devices are involved in a dynamic environment. This paper presents PhyCode, which exploits the nature of varying offsets across devices, and designs a dynamic decoding scheme which can react to the exact offsets from different signal sources simultaneously. We implement PhyCode via a software-defined radio platform and demonstrate that PhyCode achieves a lower raw BER compared with the existing state-of-the-art method.