Hexagon (Qualcomm NPU/DSP): what it is, how it works and what it does

Hexagon is the name Qualcomm assigns to its dedicated processing unit, present in its system-on-chip (SoC) designs for mobile devices. This unit fulfils a dual role: it operates as a digital signal processor (DSP) and as a neural processing unit (NPU), making it the specific hardware component for advanced processing and signal processing in Qualcomm's architecture.

What it is

Hexagon is a specialised processing unit integrated into Qualcomm SoCs. In the technical specifications of these processors it is identified under the keys dsp_type and npu, confirming its dual role. For example, in the SoC SM8850-5-AC the specification explicitly states dsp_type = Hexagon, and in the advanced processing specifications it is listed as npu = Hexagon.

Operation and principles

As a DSP, Hexagon is designed to execute signal-processing operations (audio, image, communications) efficiently and with low power consumption. As an NPU, it handles the inference of neural network models directly on the device, without the need to rely on an external server. Integrating both functions into a single unit allows Qualcomm to provide a single dedicated hardware point for advanced processing and signal tasks in its mobile platforms.

Architecture and presence in a product

The presence of Hexagon in a Qualcomm SoC datasheet manifests in the following ways:

• dsp_type = Hexagon: indicates that the digital signal processor of the chip belongs to the Hexagon family.
• npu = Hexagon or ai_npu_hexagon = NPU Hexagon: signals that the neural processing unit employed is Hexagon.
• ai_hardware_name = Hexagon: identifies the name of the advanced processing hardware in the device.

These three designations may appear simultaneously in the specifications of the same SoC, confirming that it is a single unit covering both roles.

Applications

As the dedicated NPU and DSP of the SoC, Hexagon participates in tasks such as:

• On-device inference of advanced processing models (image recognition, language processing, audio filtering).
• Real-time audio and communications signal processing.
• Energy-consumption optimisation compared to running these workloads on the general-purpose CPU.

Scope and limitations

Hexagon is a component specific to Qualcomm's SoC product line. It is not an open standard or a generic architecture: its implementation, performance, and capabilities vary according to the generation and specific model of the chip (for example, the SM8850 series). Publicly available information is limited to identifying the type of unit and its role within the SoC; internal microarchitecture details, core count, or memory bandwidth are not derived from the cited evidence.

How to interpret its presence in a product

If Hexagon appears in a mobile device's technical specifications as the DSP type or as the NPU, this indicates that the device incorporates Qualcomm's dedicated hardware for signal processing and advanced processing inference. It does not by itself imply a specific performance level, but rather the presence of the specialised unit. To assess the effective advanced processing performance of a device, one must also consider the SoC generation, available memory, and the optimisation software that accompanies the Hexagon unit.

In summary, Hexagon is the commercial and technical name of the dual processing unit (DSP + NPU) that Qualcomm integrates into its mobile SoCs to efficiently execute signal and advanced processing tasks on the device.