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5G Cellular and New Radio

5G Cellular and New Radio. Outline. 2. Is 4G enough? Basic performance measures of cellular mobile networks Part 1: Increasing the bandwidth (5G/6G) Challenges and specifics Future perspective Part 2: 5G/5G+ and New Radio Interface 5G services and requirements NR radio interface

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5G Cellular and New Radio

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  1. 5G Cellular and New Radio

  2. Outline 2 • Is 4G enough? • Basic performance measures of cellular mobile networks • Part 1:Increasing the bandwidth (5G/6G) • Challenges and specifics • Future perspective • Part 2:5G/5G+ and New Radio Interface • 5G services and requirements • NR radio interface • NR propagation • Addressing latency • Addressing reliability

  3. Satisfying growing traffic demands

  4. Is4G enough? 4 • 100Mbpsfor all subscribers in a cell! • Cell radius: ~500m-2km • Density of users:city center – 0.1-0.01humans/m^2 • Apps: email, youtube, browsing etc.

  5. Is4G enough? 5 • Exabyte: 10^18 байт... • The main question: how to get there?

  6. Important performance metrics 6 • Shannon channel capacity: • C=Blog2(1+S), • B – bandwidth • S – signal-to-interference plus noise ratio (SINR) • S=PR/(BN+I) • PR – signal power at the receiver • N – thermal noise (-174dBm/Hz), constant • I – aggregated interference • Signal power at the receiver • PR=PTAd-γ, • PT – emitter power at transmitter • A – constant that depends on antennas/frequency • d – distance between Tx and Rx • γ – ”path loss exponent”depends on environment

  7. What is interference? 7 • Interference of lightInterference in cellular mobile network

  8. How to provide 1Gbps+? 8 • How to increase the rate at the air interface? • C=Blog2[1+PR/(BN+I)]. • More sophisticated lower layer mechanisms (PHY+DL)? • Increasing emitted power? • Decrease thermal noise? • Decrease interference? • Increase bandwidth? • Network mechanisms

  9. How to provide 1Gbps+? 9 • PHY layer mechanisms? No... • FEC, MIMO, ARQ, etc.we are closer than 90% to Shannon • Increase emitted power? No... • We increase the coverage area of a cell decreasing rate • We may increase interference • Decrease thermal noise?No way... • Constant up to 0.6THz (6*1011Hz) • Superconductors atT=293K  • Decrease interference? • Logarithmic increase of C • Increase bandwidth? • Almost linear increase of C • Network mechanisms • Better spatial frequency reuse

  10. Increasing the bandwidth 10 • Shannon rate once again… • C=Blog2[1+PR/(BN+I)]. • Almost linear increase of rate • Why almost? negative effect on noise • Very effective! • Solution 1: buy more licencedfrequenues! • Commercial networks (cellular networks) • Exclusive access • Ability to use higher transmission power, >1mW • High costs and risks!!! • Less than 100-500MHzoverall in a country (less than 3GHz) • LTE: https://en.wikipedia.org/wiki/LTE_frequency_bands

  11. Increasing the bandwidth 11 • Solution 2: use the unlicensed spectrum! • ISM (Industrial, scientific, medical bands) • Extreme interference fromWi-Fi-s…

  12. Increasing the bandwidth 12 • Spectral efficiency • Bits per hertz per second • Characterizes modulation scheme • Quadrature amplitude modulation: • PSK+ASK: S(t)=Acos(ωt+φ),modulatingωand φ • <6GHz 1GHz overall: 10Gbpsonly if~10bits/Hz/s. • Using all available bandwidth below 3GHz we’ll get 10Gbps…

  13. Increasing the bandwidth 13 • Where are cellular systems in the spectrum?

  14. Increasing the bandwidth 14 • Higher frequency, more bandwidth available • 5G: millimeter wave (mmWave) • 28GHz • 60GHz (802.11ad, “new”Wi-Fi) • 72GHz • Positives • Highly directional antennas! • Negatives • Blockage by humans  • Large propagation losses • Realistically up to 100m.

  15. Increasing the bandwidth 15 • B5G, 6G: terahertz (sub-mmWave) • 275-325GHz: 50GHzof bandwidth!!! • IEEE 802.15.3d “100Gbps wireless” • http://www.ieee802.org/15/pub/SG100G.html • Positives • Even more directivity • Huge channel capacity • Negatives • Atmospheric absorption • Blockage by humans • Extreme propagation losses • Realistically up to 10-20m.

  16. 5G and New Radio Interface

  17. 5G/5G+ systems as enablers 17 • Resembles properties of CPS • Moves us closer to tactile Internet concept • Has to be supported by 5G/5G+ mobile cellular systems • At least two of the following are required • High throughput • High reliability • Low latency • Reliable service over inherently unreliable medium

  18. Envisioned 3GPP 5G Services 18 • Enhanced mobile broadband (eMBB) • Phase 1&2 are over, fully by 2020 • Massive machine-time communications (mMTC) • NB-IoT technology • Ultra-reliable low-latency services (URLLC) • Not yet available and no dates announced…

  19. 5G: evolution or revolution? 19 • Prior to 5G: just replacing RAT • 5G/5G+ systems are heterogenous in nature • New Radio (NR) RAT (28,38,72 GHz) • Multi-RAT support: LTE/NR/Wi-Fi, etc. • Advanced features: D2D, relays, femto/micro BSs • SDN/NFV capabilities for control plane • NR is expected to support URLLC service • Potential to delivery up to 10GBps per AP • Potential to upper bound latency • Potential to provide reliability • NR brings a lot of new challenges

  20. Propagation in mmWave band 20 • Highly complex compared to microwaves • Multiple paths • Material dependent • Spatial correlation • Temporal correlation

  21. Path blockage phenomenon 21 • Very small wavelengths (30GHz ~ 1mm) • Cannot penetrate through objects • Cannot “travel” around • Blockage happens at sub-second scales • Models for various environments needed • M. Gapeyenko, A. Samuylov, M. Gerasimenko, D. Moltchanov, S. Singh, M. Akdeniz, E. Aryafar, N. Himayat, S. Andreev, Y. Koucheryavy, "On the Temporal Effects of Mobile Blockers in Urban Millimeter-Wave Cellular Scenarios," IEEE Trans. Veh. Tech., 2017.

  22. Beamtracking 22 • Massive MIMO to form directional radiation patterns • Linear arrays: HPBW ~ 102/N • Positive effects: • Much less interference • Noise-limited regime? • Negative effects: • Beam alignment needed • Array switching time ~2μs • Exhaustive vs. hierarchical • Delays and loss in capacity?

  23. Beamtracking: noise-limited? 23 • Petrov, V., Komarov, M., Moltchanov, D., Jornet, J. M., & Koucheryavy, Y. Interference and SINR in millimeter wave and terahertz communication systems with blocking and directional antennas. IEEE Transactions on Wireless Communications, 16(3), 1791-1808, 2017.

  24. Beamtracking: loss in capacity 24 • Gerasimenko, M., Moltchanov, D., Gapeyenko, M., Andreev, S., Koucheryavy, Y., "Capacity of Multi-Connectivity mmWave Systems with Dynamic Blockage and Directional Antennas", Accepted to IEEE Trans. Veh. Tech., 2018.

  25. Extreme and complex path loss 25 • Received psd is • LP(f,r) – spreading losses • LA(f,r) – absorption losses • where is transmittance • K(f) – absorption coefficient • Booger-Lambert-Beer law

  26. Extreme and complex path loss 26

  27. Addressing latency 27 • Main challenge • NR frame duration: 1ms • Latency < 1ms • How to conform? • Two principal ways • Reservation/priorities • Non-orthogonal multiple access (NOMA) • Intentional overlapping of data • Enabled by flexible NR slot numerology • How to communicate decision to IoT UEs?

  28. Addressing reliability 28 • Blockage may or may not lead to outage • Case 1: blockage leads to lower MSC scheme • Case 2: blockage leads to outage • Case 1: provide more resources • Bandwidth reservation • Isolated deployments • Case 2: find a new path • 3GPP multi-connectivity • Dense deployments

  29. Reliability: multi-connectivity 29 • Avoiding outage • Gapeyenko, N., Petrov, V., Moltchanov, D., Akdeniz, M., Andreev, S., Himayat, N., Koucheryavy, Y., "On the Degree of 3GPP Multi-Connectivity in Urban 5G Millimeter-Wave Deployments", IEEE Trans. Veh. Tech., 2018.

  30. Reliability: bandwidth reservation 30 • Alleviating lower MCSs • Moltchanov, D., Samuylov, A., Petrov, V., Gapeyenko, M., Himayat, N., Andreev, S., and Koucheryavy, Y. (2018). Improving Session Continuity with Bandwidth Reservation in mmWave Communications. IEEE Wireless Communications Letters, 2018.

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