Analysis of Measured LOS Massive MIMO Channels with Mobility
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The document presents an analysis of measured line-of-sight massive MIMO channels, focusing on mobility during real-time performance evaluation in various scenarios. Key findings include a significant reduction in power de-correlation rates and improved latency with increased antenna counts, alongside an examination of channel hardening and inter-user interference. Ongoing work includes investigating non-line-of-sight de-correlation performance and its impact on achievable capacity.
Analysis of Measured LOS Massive MIMO Channels with Mobility
- 1. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Analysis of Measured LOS Massive MIMO Channels with Mobility Paul Harris* Steffen Malkowsky**, Joao Vieira**, Erik Bengtsson**, Fredrik Tufvesson**, Wael Boukley Hasan*, Liang Liu**, Mark Beach*, Simon Armour*, Ove Edfors** *Communication Systems and Networks Group, University of Bristol, Bristol, UK **Dept. of Electrical and Information Technology, Lund University, Sweden
- 2. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Summary • Lund System • Measurement Scenario • SVS Evaluation • Temporal Analysis • Real-time BERs 2
- 3. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Lund Massive MIMO Equipment 3 4x25 3.7 GHz array configuration with alternating H&V polarisationsGPS disciplined LO Closely spaced antennas on pedestrian clients Car antennas spaced by width of vehicle
- 4. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 MIMO Processor 1 MIMO Processor 2 Channel Capture 4 2GB DRAM Subcarriers 0-299 2GB DRAM Subcarriers 300-599 2GB DRAM Subcarriers 600-899 2GB DRAM Subcarriers 900-1199 SSD Host Computer MIMO Processor 3 MIMO Processor 0 RRHs
- 5. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 • 3.7 GHz Carrier • 2 Pedestrian Carts (4 spatial streams) • 2 Cars (4 spatial streams) • Temporal Analysis at <29 km/h • Real-time BERs at <50 km/h Environment Overview 5
- 6. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 • User vector normalisation: • Singular value decomposition of channel matrix for one RB: • Singular value spread is the ratio of max to min (dB) SVS Performance 6
- 7. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 SVS: Azimuth vs. Elevation 7 Trimming the azimuth Trimming the elevation
- 8. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Channel Hardening 8 • 3 second period analysed • 100 antennas vs. single antenna Fading averaged out
- 9. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Power Control Update Rates 9 • 5x reduction in the power de-correlation rate for 100 antennas over 1 antenna • Good news for power-control requirements • Reduced fading equals reduced latency 5x
- 10. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 • Temporal Correlation Function evaluated for Car2: • 7x increase in estimation rate requirements based on de-correlation rate Time Correlation of User Channels 10 7x
- 11. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Inter-user Interference 11 Normalised IUI over time at a given RB from Car 2 to Ref
- 12. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Real-Time BER Performance 12 • Speed up to 50 km/h • QPSK UL/DL • Uncoded • No power-control • No-user grouping
- 13. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Ongoing work • Investigate NLOS de-correlation performance • Evaluate the impact of de-correlation rates on achievable capacity for ZF and MF • Consider the impact of training overheads for different scenarios and dynamic training adjustment 13
- 14. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Acknowledgements and Thanks to… • Post Graduate Students: Wael Boukley Hasan, Siming Zhang, Henry Brice & Benny Chitambira • Academic Colleagues & post graduates at Lund University: Steffen Malkowsky, Joao Vieira, Liang Liu, Ove Edfurs & Fredrik Tufvesson • Academic Colleagues at Bristol: Mark Beach, Andrew Nix, Evangelos Mellios, Angela Doufexi and Simon Armour • NI Staff: Karl Nieman, Nikhil Kundargi, Ian Wong, Leif Johansson & James Kimery 14
- 15. NI Advanced Wireless Research Forum, Sydney Wednesday 7th June 2017 Thank you Work published in JSAC Special Issue on Deployment Issues and Performance Challenges for 5G. Submitted version available at https://arxiv.org/abs/1701.08818 Video of mobility trial available at https://youtu.be/wPPMrr4rHmo System description paper available at https://arxiv.org/abs/1701.01161