1. 5G Cellular and New Radio1 1

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 2

3. Satisfying growing traffic demands3 3

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

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

6. Important performance metrics6
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

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

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 8

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

10. Increasing the bandwidth10
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 MHz overall in a country (less than 3GHz)
LTE: 10

11. Increasing the bandwidth11
Solution 2: use the unlicensed spectrum!
ISM (Industrial, scientific, medical bands)
Extreme interference from Wi-Fi-s… 11

12. Increasing the bandwidth12
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

13. Increasing the bandwidth13
Where are cellular systems in the spectrum? 13

14. Increasing the bandwidth14
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

15. Increasing the bandwidth15
B5G, 6G: terahertz (sub-mmWave)
GHz: 50GHz of bandwidth!!!
IEEE d “100Gbps wireless”
Positives
Even more directivity
Huge channel capacity
Negatives
Atmospheric absorption
Blockage by humans
Extreme propagation losses
Realistically up to 10-20m. 15

16. 5G and New Radio Interface16 16

17. 5G/5G+ systems as enablers17
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

18. Envisioned 3GPP 5G Services18
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

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 19

20. Propagation in mmWave band20
Highly complex compared to microwaves
Multiple paths
Material dependent
Spatial correlation
Temporal correlation 20

21. Path blockage phenomenon21
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

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? 22

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), , 2017. 23

24. Beamtracking: loss in capacity24
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

25. Extreme and complex path loss25
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

26. Extreme and complex path loss26 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? 27

28. Addressing reliability28
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

29. Reliability: multi-connectivity29
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

30. Reliability: bandwidth reservation30
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