5G Cellular and New Radio 1 1

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 2

Satisfying growing traffic demands 3 3

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

Is 4G enough? 5 Exabyte: 10^18 байт... The main question: how to get there? 5

Important performance metrics 6 Shannon channel capacity: C=B log2(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=PT A d-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 6

What is interference? 7 Interference of light Interference in cellular mobile network 7

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 8

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 at T=293K  Decrease interference? Logarithmic increase of C Increase bandwidth? Almost linear increase of C Network mechanisms Better spatial frequency reuse 9

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 licenced frequenues! Commercial networks (cellular networks) Exclusive access Ability to use higher transmission power, >1mW High costs and risks!!! Less than 100-500MHz overall in a country (less than 3GHz) LTE: https://en.wikipedia.org/wiki/LTE_frequency_bands 10

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

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

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

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. 14

Increasing the bandwidth 15 B5G, 6G: terahertz (sub-mmWave) 275-325GHz: 50GHz of 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. 15

5G and New Radio Interface 16 16

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 17

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… 18

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 19

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

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. 21

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? 22

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. 23

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. 24

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 25

Extreme and complex path loss 26 26

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? 27

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 28

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. 29

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. 30