Outline - TSDSI | Welcome to TSDSI€¦ · PPT file · Web view · 2015-07-17Device-to-Device...
Transcript of Outline - TSDSI | Welcome to TSDSI€¦ · PPT file · Web view · 2015-07-17Device-to-Device...
Device-to-Device (D2D) Communication
Networks Lab, TCS Research
TSDSI SG1 F2F meeting, IEEE Bangalore, July 2015
2 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Outline Introduction Evolution towards 5G
Introduction – Why D2D Communication D2D Communication D2D Offloading
D2D Research at TCS Standardization of D2D Communication Conclusion
3 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Growth of Networks Challenges for future wireless communication -
Massive growth in connected devices Smart phones, laptops, sensor devices, etc
Massive growth on network traffic Almost 1000+ times or more 61% CAGR expected
Wide range of applications and their requirements Social media, video on demand, live TVs, gaming, IoT, etc
Sea of devicesExponential Growth of Network Traffic
Wide range of
requirements
4 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Can we Match to the Growth? Both backhaul as well as the access capacity should be increased Increasing Access Capacity…
Add more BTSs At present we have 7,36,654 BTS in India Tata Teleservices alone has 3000+ BTS in Bangalore New BTS will add CAPEX and OPEX
Release new spectrum Huge cost for the operators Seems to be a challenge
• Only 200+ MHz available in India Improve the spectral efficiency
Not possible always• Theoretical Limits are being reached
Usability is the key • Yet to deploy LTE Rel 8
» Spectral efficiency = 4-5 Increasing Backhaul Capacity
Nationwide optical fibre backbone Only a few operators can do this
CAPEX and OPEX issue again
Source – Huawei - The_full_spectrum_of_possibilities
Source – ITU -Link: http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2243-2011-PDF-E.pdf
5 Experience certainty.
D2D Communication Purpose
To propose/design optimal scheduling algorithms for D2D uplink/downlink in data networks such as HSPA, LTE, LTE-A, etc., networks.
D2D communication model for LTE/LTE-A systems that can be used for mobile data offloading
Why D2D?Possible to have direct communication between close proximity UEs
Reuse of cellular resources –use cellular spectrum D2D users can use same resource blocks of the cellular users Higher and better network performance than WiFi, Bluetooth, etc. Viz: in social networking, online gaming, multimedia sharing, etc.
Gain and gain Reuse gain, proximity gain, hop gain Higher data rate, low end-to-end delay
Emergency services
6 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Big Question Is it possible for UEs in proximity to communicate among themselves ?
Regular Communication Model In coverage D2D Communication Model
eNB
Data PathControl Path (C-Plane)
D2D (U-Plane)
eNB
Control Path (C-Plane)Data Path
Device to Device (D2D) Communications
7 Experience certainty.
D2D vs. M2M and Ad-hoc Networks Machine to Machine (M2M) Communication
Machine Type Communication – 3GPP TR 22.368 D2D vs. M2M
D2D vs. Ad-hoc NetworksD2D Ad-hoc Networks
Licensed and Free Spectrum Free SpectrumQoS can be ensured No QoS guarantee
Seamless Connectivity Manual ConnectivitySecurity is guaranteed Security is a challenge
D2D M2MDescribes connectivity Services Application Oriented
Direct device to device communication
Remote devices communicates through a centralized node
Access specific Access agnosticLocal comm. improves spectral
efficiencyNot applicable
8 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Classification based on Frequency of use In-band - Network assistedOut-band - Independent
Classification based on ServicesEmergency services (both in/out band)Commercial services (in-band only)
Emergency Services Commercial ServicesD2D
eNB
Control PathData Path
D2D
eNB
Control PathData Path
D2D Communication - Classification
9 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
TDD Frame structure
Technology behind D2D Communication Discovery and classifications
Discovery types Proactive – Discovery signal is per group of UEs or all UEs Reactive – Discovery signal is per UE
eNB Classifies D2D and Cellular pairs Based on - location, distance, power control, interference, etc.
Restructuring of the Scheduling procedures Scheduling of cellular and D2D transmissions
Overlapping - non-interfering same RB scheduling Non-overlapping – unused cellular RBs used for D2D
D2D frame usage In TDD – UL sub-frame (U) will be used In FDD – UL spectrum will be used
RBs can be re-used through scheduling
10 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Challenges in D2D Communications Communication Challenges
Location of the devices Ensure accuracy
Signaling techniques need to be amended Signaling overhead to be evaluated
New Modulation Schemes can be proposed Cellular: SC-FDMA Tx (UE-eNB) and OFDMA Rx (eNB-UE) D2D: SC-FDMA receiver in UE (UE-UE)
Interference Management To ensure interference below threshold in case of overlapping D2D
Power control model Select the transmit power depending on distance/channel characteristics
Channel model Short distance (indoor/outdoor) channel model can be explored
D2D traffic characterization What percentage of the users are D2D?
11 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Why LTE D2D Communication ?
LTE-D2D
Strong Resource Management
Tighter spectrum reuse
Offloading can be achieved
Better Performance
Higher data rate, low end-to-end
delay
Energy Efficient
Reliability and Scalability
Operator initiated Services
Security can be guaranteed
Regulatory and Standardization
Under 3GPP and TSD
12 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
D2D Communication @ 3GPP Standardization attempts under 3GPP Rel 12/13 (ProSe) - 3GPP TR
21.905 / TR 22.803 / TR 36.814/ TR 36.843 Discovery for ProSe
UEs at proximity should identify each other using E-UTRA/EPCProSe D2D communication
Communication between two UEs in proximity Path can be established directly or through eNB
UsageCommercial /SocialPublic Safety (with and without coverage)Network Offloading
UE -1
ProSeAPP LTE - Uu
E - UTRAN
UE-2
ProSeAPP
EPC (MME,
S/PGW)
S 1
ProSeAPP Server
SGi
ProSe Function
PC 4 PC 2
PC 5 LTE - Uu
PC 3
PC 1
PC 6
HSS/SLP
Source - 3GPP-23.703-V12.0.0
ProSe System Architecture
13 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
D2D Use Cases Usecase – 1
M2M communication using D2D underlaying LTE eNB classifies, schedules the communication
Usecase – 2 M2M communication using D2D offloading
Offloader can relay data
14 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Direct M2M under LTE Direct M2M for close proximity devices
Communicate directly whenever close to receiver (UE/eNB/AP) eNB takes care of Interference and control management Classification, scheduling, etc. through APPs
M2M offloading for bad-channel devices Remote sensors, non-LOS connections Foreign and unpredictable channel conditions Offload message packet to a nearby offloader Improved spectral efficiency and system utilization
Examples Offloading of images from cam to mobile Direct songs/images transfer from smartphone to car/home AP
15 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Evaluation of D2D Communications (1/3) Network assisted D2D is considered
Carrier frequency – 2 GHz eNB needs to identify the D2D and cellular pairs
3GPP’s D2DSS signaling for discovery Two types of communications will exist
Existing cellular communications and D2D Should not interfere in case of overlapping communication
Broad Assumptions D2D does not use the full duplex on a given carrier Mobility – 3km/hr Full synchronization between UEs and UE to eNB is possible Unicast communication only
16 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Evaluation of D2D Communications (2/3) Simulations
30% average D2D users considered Static users only
Discovery and classification Assumed 3GPP specifications for discovery Proximity based classification by eNB - proactive
Optimal D2D scheduling under LTE Two phase scheduling Modelled as a Binary Integer Program Solved using Matlab
Power control Simultaneous transmission : non-interfering
QoS Improvement Reduced delay Energy efficient Improved spectral efficiency
Network and per-user spectral efficient improved• 15% at-least
Simulation topology: Cellular vs. D2D
UE1
UE2
UE3eNB
UE1
UE2
UE3eNB
17 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
Evaluation of D2D Communications (3/3) Emulations
Through test-bed level implementation WiFi AP as LTE eNB, smartphones as UEs
Discovery based on signal strength and location Service classification – D2D/Cellular
• Depending on location, distance, interference, etc. Power control mechanism for smartphones
eNB computes required Tx power for small D2D distance eNB notifies UE the reduced Tx power, modulation, timing, etc.
TDD scheduling scheme implemented D2D & cellular transmissions on same channel Time synchronization is assumed
APP based deployment JAVA API for eNB
Desktop with Ubuntu – 14.04 as eNB Livetek WiFi adapter
Android APP for Tx, Rx (UEs) Lenovo Nexus 5, Android KitKat 4.4.2
Control Flow Diagram for D2D
Test-bed Topology
18 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
D2D
eNB
Control PathData PathOffloading Path
D2DD2D
D2D Offloading If the load at eNB is high or if the channel between the UE - eNB is
poor Offloading via another UE can be planned
Multiple UEs may be involved Effective data rate/spectral efficiency can be improved Energy saving can be achieved Both licensed and un-licensed spectrums can be used
Challenges in D2D Offloading Traffic characterization
Distorted user discovery Synchronization between UEs
Network assisted vs. independent Interference management and Scheduling Energy consumption due to sensing and location updates
19 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
D2D Offloading Evaluations Simulations
Matlab based offloading scheduling under LTE Static users, 30% are distorted (poor signal) Cell radius: 300 mt, D2D range: 5-30 mts Fixed/adaptive modulation scheme
Channel modelling Channel between UE-eNB and UE-UE Short term, long term fading is considered
Scheduling Round robin scheduling D2D transmission scheduled prior to relay
QoS Improvement Guaranteed delivery for distorted users
Low delay due to reduced failure rate Improved spectral efficiency
User and system throughput improved : 30-40% Better system utilization
20 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
D2D Offloading - Discussions Practical Deployment Scenario
Single operator case Billing is the key issue Traffic characteristics
• Data usage pattern of UEs • Signaling for distorted users – eNB assited/Distributed
Multiple operators case Further research required
Standardization Mobility modeling & dynamic classification
Location of UEs – discovery and classification Modeling the mobile channel
Secure D2D communication Control signaling, authentication, connection timing, etc.
Power-control at UE Equipment manufacturers should be involved
21 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
D2D provides one more mechanism for network offloading Is now on the way towards standardization through 3GPP
Rel 12 ProSe Discovery, ProSe Communication One-to-Many ProSe UE-to-NW relay (with no RAN impact), ECP support for WLAN
Rel 13 Communication: One-to-One communication; direct and via eNB, Service
continuity Discovery: Interaction with 3rd party apps & UE terminal apps
LTE-D2D is being positioned for emergency services in the US Is a new tool for social networking Many issues are still being unresolved and thus a fertile ground
for research
Conclusion
22 Experience certainty.
Copyright 2014 | Tata Consultancy Services Limited | Strictly Confidential
References Alastair Brydon ,"Opportunities and threats from LTE Device-to-Device (D2D)
communication",, Unwired insight - The wireless blog, Feb. 2014 X. Lin, J. G. Andrews, A. Ghosh, and R. Ratasuk, “An overview of 3GPP device-
to-device proximity services,” IEEE Communications Magazine, December 2013 X. Wu, S. Tavildar, S. Shakkottai, T. Richardson, J. Li, R. Laroia, and A. Jovicic,
“FlashLinQ: A synchronous distributed scheduler for peer-to-peer ad hoc networks,” in IEEE Allerton Conference on Communication, Control, and Computing, 2010, pp. 514–521
K. Doppler, M. Rinne, C. Wijting, C. Ribeiro, and K. Hugl, “Deviceto-device communication as an underlay to LTE-advanced networks,” IEEE Communications Magazine, vol. 47, no. 12, pp. 42–49, 2009
3GPP TR 23.703, “Study on architecture enhancements to support proximity services (ProSe) (Release 12),” v. 12.0.0, February, 2014
3GPP TR 22.803, “Feasibility study for Proximity Services (ProSe) (Release 12),” v. 12.2.0, June, 2013.
Thank You