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GR-WiFi: A GNU Radio based WiFi Platform with Single-User and Multi-User MIMO Capability

Natong Lin, Zelin Yun, Shengli Zhou, Song Han

TL;DR

GR-WiFi delivers an open-source GNU Radio platform enabling 2x2 SU-MIMO and MU-MIMO for IEEE 802.11n/ac while preserving Legacy/HT/VHT coexistence through a Cyclic Shift Diversity preamble. It combines a full PHY in software with Python-based MAC and channel sounding to achieve real-time CSI exchange without wired feedback, validated by simulations and real-world testbeds. The work demonstrates competitive performance against WIME and commercial adapters, and establishes a foundation for future research in higher spatial streams, latency-sensitive MAC design, OFDMA, and alternative multiple access schemes. Its open-source nature and real-time MU-MIMO capabilities offer a practical and scalable testbed for evaluating next-generation Wi-Fi techniques and research directions.

Abstract

Since its first release, WiFi has been highly successful in providing wireless local area networks. The ever-evolving IEEE 802.11 standards continue to add new features to keep up with the trend of increasing numbers of mobile devices and the growth of Internet of Things (IoT) applications. Unfortunately, the lack of open-source IEEE 802.11 testbeds in the community limits the development and performance evaluation of those new features. Motivated by an existing popular open-source software-defined radio (SDR) package for single-user single-stream transmission based on the IEEE 802.11/a/g/p standard, in this paper we present GR-WiFi, an open-source package for single-user and multi-user multi-input multi-output (MIMO) transmissions based on 802.11n and 802.11ac standards. The distinct features of GR-WiFi include the support of parallel data streams to single or multiple users, and the compatible preamble processing to allow the co-existence of conventional, high-throughput (HT) and very-high-throughput (VHT) traffics. The performance of GR-WiFi is evaluated through both extensive simulation and real-world experiments.

GR-WiFi: A GNU Radio based WiFi Platform with Single-User and Multi-User MIMO Capability

TL;DR

GR-WiFi delivers an open-source GNU Radio platform enabling 2x2 SU-MIMO and MU-MIMO for IEEE 802.11n/ac while preserving Legacy/HT/VHT coexistence through a Cyclic Shift Diversity preamble. It combines a full PHY in software with Python-based MAC and channel sounding to achieve real-time CSI exchange without wired feedback, validated by simulations and real-world testbeds. The work demonstrates competitive performance against WIME and commercial adapters, and establishes a foundation for future research in higher spatial streams, latency-sensitive MAC design, OFDMA, and alternative multiple access schemes. Its open-source nature and real-time MU-MIMO capabilities offer a practical and scalable testbed for evaluating next-generation Wi-Fi techniques and research directions.

Abstract

Since its first release, WiFi has been highly successful in providing wireless local area networks. The ever-evolving IEEE 802.11 standards continue to add new features to keep up with the trend of increasing numbers of mobile devices and the growth of Internet of Things (IoT) applications. Unfortunately, the lack of open-source IEEE 802.11 testbeds in the community limits the development and performance evaluation of those new features. Motivated by an existing popular open-source software-defined radio (SDR) package for single-user single-stream transmission based on the IEEE 802.11/a/g/p standard, in this paper we present GR-WiFi, an open-source package for single-user and multi-user multi-input multi-output (MIMO) transmissions based on 802.11n and 802.11ac standards. The distinct features of GR-WiFi include the support of parallel data streams to single or multiple users, and the compatible preamble processing to allow the co-existence of conventional, high-throughput (HT) and very-high-throughput (VHT) traffics. The performance of GR-WiFi is evaluated through both extensive simulation and real-world experiments.
Paper Structure (32 sections, 37 equations, 18 figures)

This paper contains 32 sections, 37 equations, 18 figures.

Table of Contents

  1. Introduction
  2. Related Work
  3. HT and VHT Packet Formats
  4. Preamble via Cyclic Shift Diversity
  5. SU-MIMO Transmission
  6. MU-MIMO Transmission
  7. Key Receiver Modules
  8. Processing the Single-Stream Preamble
  9. Packet Detection via L-STF
  10. Processing L-LTF
  11. Determining Packet Formats
  12. SU-MIMO
  13. Processing HT-LTF
  14. Processing HT Data Blocks
  15. MU-MIMO
  16. ...and 17 more sections

Figures (18)

  • Figure 1: IEEE 802.11a/g with one spatial stream, which could be transmitted by multiple antennas via cyclic shifts
  • Figure 2: IEEE 802.11n and 802.11ac packet formats with parallel data streams.
  • Figure 3: BPSK constellation (left) and QBPSK constellation (right)
  • Figure 4: Diagram of the MU-MIMO transmission procedure.
  • Figure 5: State machine of the proposed receiver for all packet formats.
  • ...and 13 more figures