Sensing Receiver

Description

A Sensing Receiver is an entity defined in 3GPP Release 19 (TS 22.137 and TS 22.837) that receives the sensing signal which the sensing service will use in its operation. It is a functional component that can reside either in a RAN node (such as a gNodeB) or in a User Equipment (UE). The sensing receiver may be co-located with the sensing transmitter in the same entity, or it may be located in a different entity, enabling monostatic, bistatic, and multistatic sensing configurations.

In a typical sensing procedure, a sensing transmitter emits a radio signal (e.g., an NR reference signal or a dedicated sensing waveform). The signal propagates through the environment, interacts with objects or the atmosphere, and is then captured by one or more sensing receivers. The receiver measures characteristics of the received signal, such as delay, Doppler shift, angle of arrival, and received power. These measurements are then processed—either locally or after being forwarded to a central sensing function—to extract information about objects (presence, distance, velocity, location) or environmental characteristics (e.g., material, weather, or motion).

The sensing receiver is a key building block of Integrated Sensing and Communication (ISAC) in 5G-Advanced and 6G. Because it can be part of a RAN node, the network can leverage existing base station infrastructure and spectrum for sensing without requiring dedicated sensor hardware. When the receiver is a UE, sensing can benefit from the wide distribution of devices and their mobility, enabling crowd-sourced or device-assisted sensing. The flexibility to separate transmitter and receiver allows for advanced sensing topologies, such as using one gNB to transmit and another to receive, which can improve coverage and reduce self-interference.

From a protocol perspective, the sensing receiver interacts with the RAN and core network through control-plane signaling that configures the sensing signal, measurement reporting, and coordination with the Sensing Function. The receiver may need to be synchronized with the transmitter and may require knowledge of the transmitted waveform to perform correlation and parameter estimation. In Rel-19, the definition focuses on the functional role; detailed procedures for configuration, measurement, and reporting are further elaborated in subsequent releases and related specifications.

Purpose & Motivation

The Sensing Receiver concept was introduced to standardize the receiving side of radio-based sensing in 3GPP networks. Before this, sensing was not a native 3GPP capability, and any radio sensing had to be implemented in a proprietary manner, often with dedicated hardware and no standardized interfaces. This limited the ability to reuse cellular infrastructure for sensing and made it difficult to integrate sensing with communication services.

By defining the sensing receiver as an entity that can be part of a RAN node or a UE, 3GPP enables a flexible and cost-effective approach to sensing. It allows operators to use existing base stations and devices as sensing receivers, potentially with only software upgrades, and it supports a variety of sensing modes (monostatic, bistatic, multistatic) by allowing the receiver to be separate from the transmitter. This flexibility is essential for optimizing sensing performance, coverage, and resource usage.

The definition also clarifies the relationship between the sensing receiver and the sensing service, ensuring that the receiver is not an isolated component but part of a larger sensing architecture that includes transmitters, a sensing function, and consumers. This standardization is a prerequisite for interoperability, multi-vendor deployments, and the eventual commercialization of sensing-as-a-service in 5G-Advanced and 6G networks.