Principles of Millimeter Wave Communications for V2X Stefano Buzzi University of Cassino and Southern Lazio, Cassino, Italy London, June 11th, 2018
About myself and the University of Cassino... - Associate Professor at the University of Cassino and Southern Latium - 20 years of experience in academic teaching and research - Currently working on 5G systems
About myself and the University of Cassino... - Associate Professor at the University of Cassino and Southern Latium - 20 years of experience in academic teaching and research - Currently working on 5G systems University of Cassino... - About 10K students, 350 Faculty, 500+ researchers - Engineering, Economics, Laws, Humanities - M.Sc. in Telecommunications Engineering (taught in English)
V2X Communications - Vehicle-to-everything (V2X) communications refer to the communication among vehicles, and among vehicles and any entity that may be interacting with the vehicle:
V2X Communications - Vehicle-to-everything (V2X) communications refer to the communication among vehicles, and among vehicles and any entity that may be interacting with the vehicle: - V2I: Vehicle-to-Infrastructure - V2V: Vehicle-to-Vehicle - V2P: Vehicle-to-Pedestrian - V2D: Vehicle-to-Device - V2G: Vehicle-to-Grid
V2X Communications - Vehicle-to-everything (V2X) communications refer to the communication among vehicles, and among vehicles and any entity that may be interacting with the vehicle: - V2I: Vehicle-to-Infrastructure - V2V: Vehicle-to-Vehicle - V2P: Vehicle-to-Pedestrian - V2D: Vehicle-to-Device - V2G: Vehicle-to-Grid - V2X has been around for a while, so is older than 5G - IEEE 802.11p dates back to 2010, and uses 10MHz bandwidth at 5.9 GHz - Currently many cars equipped with LTE transceivers
V2X Communications - Vehicle-to-everything (V2X) communications refer to the communication among vehicles, and among vehicles and any entity that may be interacting with the vehicle: - V2I: Vehicle-to-Infrastructure - V2V: Vehicle-to-Vehicle - V2P: Vehicle-to-Pedestrian - V2D: Vehicle-to-Device - V2G: Vehicle-to-Grid - V2X has been around for a while, so is older than 5G - IEEE 802.11p dates back to 2010, and uses 10MHz bandwidth at 5.9 GHz - Currently many cars equipped with LTE transceivers - V2X will be a key (if not killer...) application of 5G networks
V2X Use cases Some V2X use cases include - Forward collision warning - General warnings (traffic jam ahead, pedestrians ahead, etc...) - Infrastructure-assisted driving - Platooning - Autonomous driving - In-car entertainment
Millimeter Wave and V2X - For obvious reasons tied to reliability and coverage, sub-6 GHz frequencies have been the by default choice for V2X applications
Millimeter Wave and V2X - For obvious reasons tied to reliability and coverage, sub-6 GHz frequencies have been the by default choice for V2X applications - However, things are lately changing....
Millimeter Wave and V2X - For obvious reasons tied to reliability and coverage, sub-6 GHz frequencies have been the by default choice for V2X applications - However, things are lately changing.... - Connected cars will send 25GB of data to the cloud every hour - that is 55Mbit/s!! - A four-lane highway in normal conditions will require an aggregate throughput of tens of Gbit/s per kilometer
Millimeter Wave and V2X - For obvious reasons tied to reliability and coverage, sub-6 GHz frequencies have been the by default choice for V2X applications - However, things are lately changing.... - Connected cars will send 25GB of data to the cloud every hour - that is 55Mbit/s!! - A four-lane highway in normal conditions will require an aggregate throughput of tens of Gbit/s per kilometer - On top of that, we could want to provide in-car entertainment to passengers
Millimeter Wave and V2X - For obvious reasons tied to reliability and coverage, sub-6 GHz frequencies have been the by default choice for V2X applications - However, things are lately changing.... - Connected cars will send 25GB of data to the cloud every hour - that is 55Mbit/s!! - A four-lane highway in normal conditions will require an aggregate throughput of tens of Gbit/s per kilometer - On top of that, we could want to provide in-car entertainment to passengers - For providing these services, mmWave carrier frequencies are needed!
Millimeter Wave and V2X - For obvious reasons tied to reliability and coverage, sub-6 GHz frequencies have been the by default choice for V2X applications - However, things are lately changing.... - Connected cars will send 25GB of data to the cloud every hour - that is 55Mbit/s!! - A four-lane highway in normal conditions will require an aggregate throughput of tens of Gbit/s per kilometer - On top of that, we could want to provide in-car entertainment to passengers - For providing these services, mmWave carrier frequencies are needed! - The research community is already tackling this challenge (e.g. 5G-MiEdge, 5GCAR, plus privately-funded research)
Millimeter Waves (mmWaves) One of the ”key pillars” of 5G networks Refers to above-6Ghz frequencies Regulators worldwide are releasing spectrum chunks at frequencies up to 100GHz The main benefit here is the availability of large bandwidths
Millimeter Waves (mmWaves) One of the ”key pillars” of 5G networks Refers to above-6Ghz frequencies Regulators worldwide are releasing spectrum chunks at frequencies up to 100GHz The main benefit here is the availability of large bandwidths However, there are some key challenges that are to be faced to realize effective wireless communications with mmWave frequencies
The Propagation Challenge � λ � 2 - Friis’ Law: P R = P T G T G R 4 π d
The Propagation Challenge � λ � 2 - Friis’ Law: P R = P T G T G R 4 π d - We may have heavy shadowing losses: brick, concrete > 150 dB Human body: Up to 35 dB
The Propagation Challenge � λ � 2 - Friis’ Law: P R = P T G T G R 4 π d - We may have heavy shadowing losses: brick, concrete > 150 dB Human body: Up to 35 dB NLOS propagation mainly relies on reflections There are heavy blockage effects
Increased atmospheric absorption
Small-sized arrays help! However...
Small-sized arrays help! However... - For a constant physical area, G T and G R ∝ λ − 2 - Otherwise stated, the number of antennas that can be packed in a given area increases quadratically with the frequency
Small-sized arrays help! However... - For a constant physical area, G T and G R ∝ λ − 2 - Otherwise stated, the number of antennas that can be packed in a given area increases quadratically with the frequency ⇒ - The free-space path loss is well-compensated by the antenna gains = mmWaves must be used in conjunction with MIMO
The case for doubly massive MIMO at mmWaves - At f c = 30 GHz , the wavelength λ = 1cm - Assuming λ/ 2 spacing, ideally , more than 180 antennas can be placed in an area as large as a credit card
The case for doubly massive MIMO at mmWaves - At f c = 30 GHz , the wavelength λ = 1cm - Assuming λ/ 2 spacing, ideally , more than 180 antennas can be placed in an area as large as a credit card The number climbs up to 1300 at 80GHz!!
The case for doubly massive MIMO at mmWaves - At f c = 30 GHz , the wavelength λ = 1cm - Assuming λ/ 2 spacing, ideally , more than 180 antennas can be placed in an area as large as a credit card The number climbs up to 1300 at 80GHz!! Although clearly not feasible in today’s mobile phones, doubly massive MIMO systems are a perfect match for V2X communications
Other challenges/difficulties - The MIMO channel at mmWaves is not so generous as in sub-6GHz bands
Other challenges/difficulties - The MIMO channel at mmWaves is not so generous as in sub-6GHz bands - ADC/DAC bottleneck: forget all-digital beamforming and use alternative solutions: (hybrid analog/digital beamformers, lens antenna arrays, single-RF chain architectures, etc.)
Other challenges/difficulties - The MIMO channel at mmWaves is not so generous as in sub-6GHz bands - ADC/DAC bottleneck: forget all-digital beamforming and use alternative solutions: (hybrid analog/digital beamformers, lens antenna arrays, single-RF chain architectures, etc.) - Power consumption issues (not so relevant for V2X)
Other challenges/difficulties - The MIMO channel at mmWaves is not so generous as in sub-6GHz bands - ADC/DAC bottleneck: forget all-digital beamforming and use alternative solutions: (hybrid analog/digital beamformers, lens antenna arrays, single-RF chain architectures, etc.) - Power consumption issues (not so relevant for V2X) - Low efficiency of power amplifiers (moderately relevant for V2X)
Other challenges/difficulties - The MIMO channel at mmWaves is not so generous as in sub-6GHz bands - ADC/DAC bottleneck: forget all-digital beamforming and use alternative solutions: (hybrid analog/digital beamformers, lens antenna arrays, single-RF chain architectures, etc.) - Power consumption issues (not so relevant for V2X) - Low efficiency of power amplifiers (moderately relevant for V2X) - Need for efficient beam-alignment and tracking (positioning may help...)
Lecture Outline We now focus on:
Lecture Outline We now focus on: The MIMO channel at mmWaves
Lecture Outline We now focus on: The MIMO channel at mmWaves Hybrid (analog/digital) beamforming architectures
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