UHD (USRP Hardware Driver) is the free and open-source software driver and API for the Universal Software Radio Peripheral (USRP) platform, created and sold by Ettus Research. It gives developers a unified, hardware-abstracted interface for configuring USRP devices, streaming complex baseband samples, and building complete SDR applications—whether running standalone C++ and Python programs or integrating with third-party frameworks like GNU Radio, MATLAB, or srsRAN.Documentation Index
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What is UHD?
UHD is the official driver layer that sits between your application code and Ettus Research USRP hardware. It handles all low-level concerns—device discovery, link-layer encapsulation, clock and time synchronization, gain and frequency tuning, and high-throughput sample streaming—so that application code only needs to interact with a clean, consistent API. The driver is organized around a high-level Multi-USRP abstraction (uhd::usrp::multi_usrp) that works for a single USRP with one or more channels, and equally well for multiple USRPs in a homogeneous configuration. For more advanced use cases—such as directly wiring RFNoC signal-processing blocks together—a lower-level RFNoC graph API (uhd::rfnoc::rfnoc_graph) is also available.
UHD is primarily developed on Linux and is actively tested on macOS and Windows. The source tree includes the user-space host driver (host/), embedded peripheral manager firmware (mpm/), FPGA image sources (fpga/), and microprocessor firmware (firmware/).
Supported Hardware
UHD supports the full catalog of Ettus Research USRP hardware, including all current and legacy motherboards and their associated daughterboards. This covers:- USRP B-Series – USB-connected, bus-powered devices (B200, B210, B200mini, B205mini)
- USRP N-Series – 1 GbE and 10 GbE networked devices (N200, N210, N300, N310, N320, N321)
- USRP X-Series – High-performance, multi-channel devices (X300, X310, X410, X440)
- USRP E-Series – Embedded, standalone devices (E310, E312, E320)
- USRP X4xx / N3xx – RFNoC-native Generation-3 and Generation-4 platforms
OS Support
UHD is officially built and tested on the following operating systems:| Operating System | Notes |
|---|---|
| Linux | Primary development platform; Fedora and Ubuntu distributions are explicitly tested |
| Mac OS X | Intel-based Macs are supported |
| Windows 10 | Fully supported; installers are provided by Ettus Research |
Key Capabilities
Multi-USRP API
The
uhd::usrp::multi_usrp class provides a single high-level object that uniformly controls one or many USRP devices. Configure sample rate, center frequency, gain, antenna, bandwidth, clock source, and time reference through a consistent set of get/set methods.High-Throughput Streaming
RX and TX streamers (
uhd::rx_streamer, uhd::tx_streamer) deliver complex baseband samples between the host and device with configurable host CPU formats (fc32, fc64, sc16) and over-the-wire formats (sc16, sc8). Automatic format conversion is handled internally.RFNoC Graph API
Generation-3 and later USRPs expose an RF Network-on-Chip (RFNoC) fabric. The
uhd::rfnoc::rfnoc_graph API lets you discover, connect, and configure on-device DSP blocks—DDCs, DUCs, FIR filters, FFTs, replay buffers—without touching the host CPU.C, C++, and Python APIs
Write applications in C++ using
uhd::usrp::multi_usrp, call the Python bindings via uhd.usrp.MultiUSRP, or integrate from C with the built-in C API wrapper. All three interfaces expose the same device capabilities and are included in every standard UHD build.Clock & Time Synchronization
Select clock and PPS sources (internal, external, GPSDO, MIMO) at runtime. Set absolute time references for deterministic, phase-coherent multi-channel and multi-device operation. Timed command queuing enables sub-microsecond synchronization across devices.
Remote Streaming
RFNoC devices (X440, X410, X3x0, N3xx, E320) and the legacy N200/N210 support streaming sample data directly to an alternative network destination instead of back to the controlling UHD host, enabling distributed SDR deployments.
API Interfaces
UHD exposes three tiers of API to match different application needs: C++ (uhd::usrp::multi_usrp) — The primary, full-featured interface. Construct a device object with multi_usrp::make(args), configure all radio parameters, then call get_rx_stream() or get_tx_stream() to obtain a streamer. All examples in the UHD source tree use this interface.
Python (uhd.usrp.MultiUSRP) — Auto-generated Python bindings that mirror the C++ API. Ideal for rapid prototyping and integration with NumPy-based signal processing pipelines. The uhd.usrp.MultiUSRP constructor accepts the same device address strings as the C++ make() call.
C API — A stable C-linkage wrapper included by default in all UHD builds. Suitable for embedding UHD in non-C++ projects or when binary ABI stability is required. See the C API documentation for the full function reference.
Third-Party Integrations
UHD-based USRP devices are supported natively by a broad ecosystem of SDR frameworks and commercial toolchains:- GNU Radio — Flow-graph SDR toolkit with
gr-uhdsource and sink blocks - RFNoC OOT Blocks — Out-of-tree RFNoC signal-processing blocks for USRP Gen-3 and later devices
- NI LabVIEW – UHD RFNoC — LabVIEW FPGA integration examples for RFNoC-capable USRPs
- NI LabVIEW — LabVIEW instruments and driver support for USRP hardware
- MathWorks MATLAB & Simulink — Hardware support package for USRP
- REDHAWK — Government and defense SDR framework
- OpenBTS and Osmocom GSM — Open-source cellular infrastructure stacks
- Amarisoft LTE — Commercial LTE/5G NR base-station software
- Software Radio Systems srsRAN — Open-source 4G/5G RAN stack
- Eurecom OpenAirInterface — Open-source 5G research platform
For complete installation instructions, build guides, and device-specific configuration reference, see the official UHD and USRP Manual. The Ettus Research Knowledge Base contains additional application notes, tutorials, and the Technical FAQ.