5G Millimeter-Wave and

Device-to-Device Integration
By: Niloofar Bahadori
Advisors: Dr. B Kelley,
Dr. J.C. Kelly

Spring 2017
Outline
• 5G communication Networks
• Why we need to move to higher frequencies?
• What are the characteristics of mmWave band communications?
• What are the challenges in using mmWave?
• How mmWave challenges can improve D2D communication performance?
• Challenges of D2D mmWave
• Hybrid D2D network
• Simulation Result
 5G networks

Network Specification 5G 4G
Peak Data Rate 10 Gb/s 100 Mb/s
Mobile Data Volume 10 Tb/s/k𝑚2 10 Gb/s/k𝑚2
E2E Latency 5 ms 25 ms
Energy Efficiency 10% current consumption
Number of Devices 1 M/k𝑚2 1 k/k𝑚2
Mobility 500 km/h -
Reliability 99.999% 99.99%
 5G networks
Carrie #1: 20 MHz
Existing solutions to improve
Carrie #2: 20 MHz
network capacity:
• Increase Available BW Carrie #3: 20 MHz
100 MHz

• Carrier Aggregation Carrie #4: 20 MHz

• Cognitive Radio Carrie #5: 20 MHz

• Spectrum Reuse
• D2D Communication
• Small Cell network
• Increase Spectral Efficiency
• Massive MIMO
• Spectrum Sharing
Even though some of these techniques can boost
performance significantly, there is no clear
roadmap on how to achieve the so far defined
5G performance targets.
 U.S. Frequency Allocation
The Radio Spectrum
AM Broadcast

TV Broadcast

Cellular Communication
Wi-Fi

Equivalent Spectrum

Source: U.S. Dept. of Commerce, NTIA Office of Spectrum Management

mmWave Communication
• Microwave band is referred to as Sweet spot due to its favorable propagation characteristics
• Low frequency bands have been almost used up
• It is difficult to find sufficient frequency bands in the microwave range for 5G improvements
• mmWave with high bandwidth can be a potential solution for 5G communication
• However, wave propagation in mmWave band has specific characteristics that should be considered
in design of network architecture

3 GHz 57-64 164-200 300 GHz

Candidate Bands
27.5–28.35 31.225–31.3
54 GHz 99 GHz 99 GHz
29.1–29.25 71-76
Cellular communication
31.075–31.225 81-86
Oxygen molecule Absorption Water Absorption
31.0–31.075 92-95
Potential available bandwidth
 mmWave Characteristics
Atmospheric Absorption
• Raindrops are roughly the same size as the radio wavelengths (millimeters) and therefore cause scattering
of the radio signal
• The rain attenuation and molecular absorption characteristics of mmWave propagation limit the range of
mmWave communications

The rain attenuation

and atmospheric
absorption do not
create significant
additional path loss for
cell sizes on the order
of 200 m.

Source: E-band technology. E-band Communications. [Online]. Available: http://www.e-band.com/index.php?id=86.

mmWave Characteristics
High Propagation Loss and Sensitivity to Blockage
• mmWave communication suffers from high propagation loss 𝑃𝐿 ∝ 𝑓 2
• Electromagnetic waves have weak ability to diffract around obstacles with a NLOS path

size significantly larger than the wavelength

• For example, blockage by a human attenuate the link budget by 20-30 dB
• Only LOS communication is efficient.
LOS path

Oxygen
Frequency PLE- LOS PLE- NLOS Rain Attenuation
Absorption
Band (GHz) @200 m (dB)
@200 m (dB)
28 1.8~1.9 4.5~4.6 0.9 0.04 𝑑
𝐹 𝑑 = 𝑃𝐿(𝑑0 ) + 10𝑛𝑙𝑜𝑔10
38 1.2~2 2.7~3.8 1.4 0.03 𝑑0
60 2.23 4.19 2 3.2
73 2 2.45~2.69 2.4 0.09 Path-loss Exponent (PLE)

NLOS suffer from high attenuation

mmWave Characteristics
Directivity
• To combat severe propagation loss, high gain, directional
antennas are employed at both transmitter and receiver
• Beamforming is a key enabling technology of mmWave
communication
• With a small wavelength, electronically steerable antenna
arrays can be realized as patterns of metal on circuit board

IBM Breakthrough Could Alleviate

Mobile Data Bottleneck IBM: The packaged transceiver
operates at frequencies in the Directional antenna
range of 90-94 GHz. High gain at one
It is deployed as a unit tile, direction
combining 4 phased array ICs very low gain in all
and 64 dual-polarized other directions
antennas.

IEEE RFIC 2014 Seattle, WA

D2D Communication
D2D communication allows mobiles to establish a direct connection without traversing the
eNodeB (or BS).
D2D is a key component in the context of IoT, since a substantial fraction of the traffic is
generated and consumed locally.
Eliminating the eNodeB from the transmission path leads to:
• Higher spectral efficiency
• Lower signaling overhead
• Higher energy efficiency
• Increase the coverage of cell edge UEs
• Reduce the traffic load of BS

However, these gains can only be achieved if we can overcome several challenges faced by
D2D communication.
 D2D Communication
Main problem in D2D: Interference Management

D2D over ISM band (using WiFi) D2D over licensed band
• Devices compete to achieve channel • Guaranteed communication quality
access • Require accurate interference management
• Little interference control between cellular and D2D users
• Quality of communication is not
guaranteed.

Several techniques are proposed to solve these challenges. Still D2D link capacity is significantly
affected by the network density:
• Insufficient communication bandwidth
• Significant interference caused due to the omni-directional nature of communication
 mmWave Shortcomings Advantage for D2D
Some of the mmWave communication challenges are desirable features for D2D communication:
• High path loss
• Directional beam forming
• Less interference
• Improve spatial reuse
• High bandwidth
• Supports high throughput D2D applications
Challenges
• Narrow beam width
• Low antenna height in D2D communication comparing to BS height
Makes devices more vulnerable to blockage which may cause difficulty to fulfill D2D device discovery and
beam alignment.

Hybrid communication: works on mmWave in Line-of-Sight (LoS) case and switch back to microwave in case of
blockage, and exchange control signaling in microwave to aid the alignment for mmWave.
 mmWave D2D integration
Beam alignment protocol
1. BS finds that there is a UE who wants to communicate directly with another UE in its cell
2. BS broadcasts this information as a D2D-link-set-up-request to both UEs.
3. DUE pair receive the request and prepare for the beam alignment process (micro wave
band)
4. DUE A will send channel probing signals from each of its sectors in a cycle, and B will
receive at each of its sectors and keep recording the signal strength (𝐴𝑘 × 𝐵𝑛 )
5. BS gets the feedback of the power strength from B and convey information to A.
LoS Link: If the mmWave power received by B in some sector is greater than a
minimum power threshold (T), BS will send A the information: mmWave
communication.
Blockage: If none of B’s sectors received enough power higher than the threshold,
which shows there are blockages in the link, BS will inform A to communicate with
B on micro wave band
𝑃11 ⋯ 𝑃1𝑛 A1 … Ak B1 … Bn

6. A begins to communicate with B in micro wave or mmWave. ⋮ ⋱ ⋮

𝑃𝑘1 ⋯ 𝑃𝑘𝑛
mmWave D2D integration
Assumptions
Location of BSs: The locations of the BSs form a homogeneous Poisson Point Process (PPP) 𝜙 on the plane
with density 𝜆𝐵 and all BSs employ constant downlink transmission power 𝑃𝐵.
Location of DUEs: The D2D users form another homogeneous PPP 𝜙 on the plane with density 𝜆𝐷 . The
DUE reuse the downlink resource of the cellular links.
Blockage model: The blockages are modeled as another PPP of buildings independent of the
communication network. Each point of the building PPP is independently marked with a random width,
length, and orientation
Beam-Forming : In millimeter wave band, antenna arrays at the base stations and DUEs are all adopted for
directional communication. Angle gain between the transmitter beam and the receiver beam is denoted as
𝐺(𝜃𝑡, 𝜃𝑟), and the maximum achievable array gain is 𝐺(0, 0). In microwave band they use omni-directional
antenna.
Beam Alignment: Due to small size of antenna, they can be used in large scale at equipment to obtain high
gain communication. The main beams of the transceiver antennas are perfectly aligned with each other
when transmission is being carried on.
mmWave D2D integration
Converge probability:
𝑃 = 𝑃 𝑆𝐼𝑁𝑅 > 𝑇
Microwave Mode:
𝜇𝑚𝑖𝑐𝑟𝑜 𝑟 −𝛼 ℎ𝐷𝐷
𝛾𝑚𝑖𝑐𝑟𝑜 =
𝐼𝐵𝐷 +𝐼𝐷𝐷 +𝜎 2
mmWave Mode:
2𝜆 𝑏𝑙𝑜𝑐𝑘𝑎𝑔𝑒 𝐸 𝑤 𝐸[𝐿]
Probability of blockage : 𝑎 = 1 − 𝑒 −𝛽𝑑 , 𝛽 = 𝜋
𝜇𝑚𝑚 α 0 𝑔(𝑟0 )
𝛾𝑚𝑚 = 2
𝜎 + σ𝐾−1
𝑘=0 𝜇𝑚𝑚 α[𝜃𝑘 ]𝑔(𝑟𝑘 )
Hybrid Mode:
𝑃 𝑆𝐼𝑁𝑅 > 𝑇 = 𝑎 𝑃 𝑆𝐼𝑁𝑅𝑚𝑚 > 𝑇 + 1 − 𝑎 𝑃(𝑆𝐼𝑁𝑅𝑚𝑖𝑐𝑟𝑜 > 𝑇)
Simulation result
Parameter Value
Density of BSs 𝜆𝐵 1 × 10−6 𝑚2
Density of DUEs 𝜆𝐷 1 × 10−5 𝑚2
Density of Blockages 1 × 10−5 𝑚2
Transmitting power of BS 𝜇 𝐵 30dBm
Transmitting power of DUE in micro wave 𝜇𝑚𝑖𝑐𝑟𝑜 23dBm
Transmitting power of DUE in mmWave 𝜇𝑚𝑚 23dBm
SINR threshold T -10dB
Microwave Path loss exponent 3
mmWave path loss 4
Noise Power -87dBm
Average blockage width 50m
Average blockage length 50m
Carrier frequency in mmWave 28 GHz
Simulation Result
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