Generations of Mobile Standards

New Radio (NR) positioning support

Aug 30,2023

By Carolyn Taylor, 3GPP MCC

The positioning work in 3GPP over New Radio (NR) is aimed at indoor and outdoor use cases, exploiting 5G features such as high bandwidth, massive antenna systems, evolved network architecture which are all helping to facilitate the arrival of massive numbers of IOT device types on the scene.

One major use case for NR positioning is Emergency call. In 3GPP Rel-16 a study was conducted to evaluate E911 requirements for positioning accuracy (latitude, longitude, and altitude), network availability, reliability and latency. It also looked at synchronization requirements and the level of complexity experienced in meeting the needs of emergency call related to positioning. Specifications followed for a variety of positioning techniques that support regulatory as well as commercial needs.

On the commercial side, the key NR design target for positioning was the definition of a range of accuracy levels, latency levels. The Rel-16 performance metrices used for evaluating performance of NR positioning are:

Rel-16 Horizontal accuracy
Horizontal accuracy is the difference between the calculated horizontal position and the actual horizontal position of a UE. The target horizontal positioning requirements for commercial use cases was <3 m for indoor scenarios and <10 m for outdoor scenarios with 80% of UEs.
Rel-16 Vertical accuracy
Vertical accuracy is the difference between the calculated vertical position and the actual vertical position of a UE. The target vertical positioning requirements for commercial use cases was <3 m for indoor and outdoor scenarios with 80% of UEs.
Rel-16 Latency level
The 5G communication for automation in vertical domains necessitates low latency. The performance target requirement considered for latency level was end-to-end latency < 1s.

 

The Rel-17 specification, 3GPP TS 22.261 - Service requirements for the 5G system – looked further at the evolving needs of the ‘verticals’ for high accuracy (horizontal and vertical), low latency, network efficiency and device efficiency for commercial use cases and for Industrial IoT.

The Rel-17 performance metrices for positioning are:

Rel-17 Horizontal accuracy
Target horizontal positioning requirements for commercial use cases is < 1 m for 90% of UEs, with requirements for IIoT use cases at < 0.2 m for 90% of UEs.
Rel-17 Vertical accuracy
The target vertical positioning requirements for commercial use cases is < 3 m for 90% of UEs, with  requirements for IIoT use cases at < 1 m for 90% of UEs.
Rel-17 Latency level
End-to-end latency for position estimation of UE (< 100ms, in the order of 10 ms is desired)
Physical layer latency for position estimation of UE (<10ms)

 

In 3GPP Rel-18, there are two additional techniques being considered to provide higher accuracy:

  1. Taking advantage of 5G spectrum to increase the bandwidth for the transmission and reception of the positioning reference signals based on PRS/SRS bandwidth aggregation for intra-band contiguous carriers.
  2. Use of NR carrier phase measurements. GNSS carrier phase positioning has been used very successfully for centimetre-level positioning accuracy in outdoor applications.

Other Rel-18 enhancements to Sidelink positioning will also help, with Sidelink ranging/positioning enabling Low Power High Accuracy Positioning (LPHAP) and the support of positioning for UEs with Reduced Capabilities (RedCap UEs).

Further Reading

See the full Work Plan at https://www.3gpp.org/specifications-technologies/3gpp-work-plan

The following ‘Positioning’ lines are from the Work Plan (Level 1 items only).

SID / WID  Title Acronym  Rel WG   See:
 910040 Ranging-based Service and sidelink positioning  Ranging  18 22.261
 940081 Study on expanded and improved NR positioning FS_NR_pos_enh2  18  R1 38.859
 981038 Expanded and improved NR positioning 

NR_pos_enh2

 18 
 910036 Low Power High Accuracy Positioning for industrial IoT scenarios LPHAP  18  S1 22.104; 22.261 
 900060 RAN aspects of NR positioning enhancements  NR_pos_enh  17
 880075 Study on scenarios and requirements of in-coverage, partial coverage, and out-of-coverage NR positioning use cases FS_NR_pos_cov  17  RP
 800013 5G positioning services 5G_HYPOS  16  S1 22.261
 830077 NR positioning support NR_pos   16  R1
 890045 UE Conformance Test Aspects - B1C Signal in BDS Positioning System Support for LTE and NR B1C_BDS_pos_UEConTest  16  R5
 750063 UE Positioning Accuracy Enhancements for LTE  LCS_LTE_acc_enh    15  R2