Positioning, or locating, devices using wireless signals such as global positioning system (GPS) has become a ubiquitous technology in today’s world. We regularly rely on positioning systems to tell us how to drive somewhere, where to catch the train, and how to get to the closest restaurant. While many of these daily applications of positioning systems use GPS (or other satellite systems), cellular systems have also provided positioning services for over a decade now (e.g.,in 3G and 4G). 5G New Radio (NR) is no different and due to the ever-increasing bandwidths of cellular systems and other improvements in cellular technologies there has been a recent increase in research activity, in academia and industry, for cellular based positioning technology.
Among the new positioning use cases addressed in 3GPP Rel-18 is Reduced Capability (RedCap) positioning support. 5G NR support for RedCap devices was introduced in 3GPP Rel-17 as a lower cost, simpler device type to address various IoT use cases. RedCap devices were introduced to target use cases including wearables (e.g., smart watches), industrial sensors, and the smart grid. RedCap devices achieve lower cost due to a reduced maximum bandwidth (compared with full capability devices), reduced number of antennas, and lower order modulation support. Tracking of wearables, as shown in Figure 1, is an example use case of RedCap positioning support in 5G NR.
In this whitepaper, we will discuss the RedCap positioning techniques developed by 3GPP. Namely we discuss the frequency hopping techniques in the downlink (DL) and uplink (UL) enabling RedCap devices to achieve similar positioning performance as full capability devices.
