5G Positioning for connected cars (mmW) 5G introduction - PowerPoint PPT Presentation

5G Positioning for connected cars ▪ (mmW) 5G introduction ▪ Mathematical model of 5G-mmW positioning ▪ Mutiple aspects of the achievable error ▪ Estimation principle Summer school on 5G V2X communications June 2018 Giuseppe Destino, CTR, King’s College London

5G vs LTE-A (4G) 5G New carrier frequencies (sub-6 GHz and mmW)  Beam-based communication  New radio-access procedures  New communication models  Location-awareness 

Radio-frequency map 0.8 GHz 6 GHz 100 GHz Frequency 37-40 64-71 3.5-5 24-28 0.8-2.8 GHz GHz GHz GHz GHz 4G 5G 5G 5G 5G 10m 1m 200m 10Km Range Medium range Very-short Wide range uRLLC Com eMBB mMTC

mmW sparse channel model (Physical)  Representation with 4 physical dimensions  Sparse due to high carrier frequency

5G positioning: what is new Single BTS approach  Use channel sparsity  Use direction and distance  infromation jointly Use a geomteric model to exploit  one-bounce link

Positioning technology landscape Availability Satellite remote positioning rural A-GNSS CI / E-CID sub- (GPS, GLONASS, …) urban based methods city WiFi in-door BLE/UWB Accuracy 1m 3 10 50 100 300 1km 3km 10km

5G Positioning: mathematical model  Estimate location and rotation of the MS  Location-based channel parameterisation

When can we do positioning Positioning using beam sweeping Positioning using reference signals https://www.keysight.com/upload/cmc_upload/All/Understanding_the_5G_NR_Physical_Layer.pdf Inital access Sweeping multiple directions allows channel discovery  No overhead (or reduced is specific pilots are needed)  Periodically to allow location tracking  Benefit Location-awareness prior communications 

Signalling for positioning DATA Beam Training DL UE collects and processes signals over multiple beams  UL gNB collects and processes signals over multiple beams  Received OFDM signal at the m-th RF chain

Analysis of the Position FIM More information by increasing the subcarrier spacing More information by using edge-band subcarriers Bearing information depends on the sensitivity of the beampattern in angle domain No derivations … AoA and AoD are coupled

Tool for performance analysis : CRLB FIM for channel parameters  Apply variable transformation  Compute the CRLB from the inverse of 𝐊 η  G. Destino , H. Wymeersch, “On the Trade-off Between Positioning and Data Rate for mm- Wave Communication”, in IEEE International Conference on Communications Workshops, 2017

Position-rotation error bound DL mode LoS link provides 3 types of information  AoA information: position-rotation dependent  AoD information: position dependent  Ranging: position dependent  NLoS link provides a combined infromation  AoA-Ranging information: position-scatter-rotation  dependent The FIM of Position-Rotation in rank 3 in 2D,  therefore position-rotation is feasible with 1 LOS + N >= 0 NLOS  N >=3 NLOS  R. Mendrzik , et All., “Harnessing NLOS Components for Position and Orientation Estimation in 5G mmWave MIMO”, arxiv 2017

Pilot signals Distributed Center-localised Edge-localised

Ranging error Scenario: AoA = 0 deg, AoD = 180 deg, d = 100m, 2 RF chains, 16 ULA

Ranging error 2 RF chains Impact of array gain Scenario: AoA = 0 deg, AoD = 180 deg, d = 100m, 2 RF chains, 16 ULA, orthogonal beams

Bearing error Due to the derivative of the beamforming Scenario: AoA = 0 deg, AoD = 180 deg, d = 100m, ULA, orthogonal beams

Achievable localisation error

Achievable localisation error

Requirements for 5G positioning AoA and AoD information  Multiple beamforming to acquire information about AoA, AoD  LOS / LOS and >1 NLOS / >= 3 NLOS  Narrow beams for high SNR and high AoA/AoD resolution  ’Spread’ pilots for high delay resolution 

Sweeping strategy Hierarchical search Exhaustive search

Impact of beam training searching strategy Exhaustive search   Information is acquired when main beam or sidebeam ”hit” the LOS ray  Resource consuming  Beam-codebook dependent Hierarchical search   Infromation is acquired at each step of the search  High accuracy can be achieved as beams point to the ”right” direction  Time efficient

Trade-off: Rate vs Accuracy • Hierarchical search: more time efficient but more sensitive to noise • Exhaustive search: more robust to noise, trade-off between rate and positioning accuracy

Rate-PEB joint resource optimization User rate Time sharing optimisation

Position-estimation approach A. Shahmansoori, G. E. Garcia, G. Destino, G. Seco-Granados and H. Wymeersch, "Position and Orientation Estimation Through Millimeter-Wave MIMO in 5G Systems," in IEEE Transactions on Wireless Communications , vol. 17, no. 3, pp. 1822- 1835, March 2018

Structured sparsity Angular domain Subcarrier 1  Signals over multiple subcarriers share the same ”angular information”  Signals over multiple Subcarrier 2 MIMO channels share the same ”time information” Subcarrier N

Two-step estimation in a nutshell  Step1: Sparse estimation with common support  Exploit common spatial-sparsity across carriers  CS technique for common support model  Estimate delay and channel gain per path  Step2: Refinement of the channel parameters  SAGE: per path refine the channel parameters using a successive cancellation method  Step3: Non-linear mapping to location  Solve non-linear least square problem

5G – GNSS hybrid solution Sat1 Sat2 ψ 1 ψ 2 BTS θ 1 θ 2 MS - θ 0 - α On going work !

Reading H. Wymeersch, G. Seco-Granados, G. Destino, D. Dardari and F. Tufvesson, " 5G mmWave 1. Positioning for Vehicular Networks ," in IEEE Wireless Communications , vol. 24, no. 6, pp. 80-86, Dec. 2017. A. Shahmansoori, G. E. Garcia, G. Destino, G. Seco-Granados and H. Wymeersch, " Position 2. and Orientation Estimation Through Millimeter-Wave MIMO in 5G Systems ," in IEEE Transactions on Wireless Communications , vol. 17, no. 3, pp. 1822-1835, March 2018 G. Destino and H. Wymeersch, " On the trade-off between positioning and data rate for 3. mm-wave communication ," 2017 IEEE International Conference on Communications Workshops (ICC Workshops) , Paris, 2017, pp. 797-802. J. Saloranta, G. Destino and H. Wymeersch, " Comparison of different beamtraining 4. strategies from a rate-positioning trade-off perspective ," 2017 European Conference on Networks and Communications (EuCNC) , Oulu, 2017, pp. 1-5. G. Destino , J. Saloranta, H. Wymeersch and G. S. Granados, “ Impact of Imperfect Beam 5. Alignment on the Rate-Positioning Trade-Off ”, 2018 IEEE Wireless Communications and Networking Conference (WCNC): Special Session Workshops