Low Latency Communications for Wireless
Exploiting Traffic Characteristics
September 19, 2019
1 Project background and industrial motives
The main goal of the next generation mobile communication is to provide
seamless communication for a massive amount of devices building the
Internet-of-Things (IoT) and at the same time to support the constantly
increasing traffic demands originated from personal communications. The major
difference between 5G and the previous generations is the native support of ultra
reliability, low latency, and the massive access. Ultra-high reliability and
ultra-low latency are required by several applications and services such
as autonomous vehicles, factory automation, telepresence, smart grids
One of the major impacts of 5G will be the transformation of the industrial
production into Industry 4.0. The term Industry 4.0 captures the fourth
industrial revolution that transforms industrial manufacturing systems into
cyber-physical systems by introducing novel communications techniques such as
5G connectivity and cloud computing .
Latency is crucial in applications such as automated industrial production,
automatic control, robotics, transportation, health-care, education etc.
An indicative list of latency-constrained services that will be supported
by 5G are given below . Factory Automation includes real-time
control of machines and systems for fast and massive production lines
with limited human involvement has challenging requirements in terms of
latency and reliability. The latency requirement for factory automation
applications varies between 0.25 - 10 ms with a packet loss rate of 10-9.
Autonomous driving and optimization of road traffic requires ultra reliable low
latency communication. According to Intelligent Transport Systems
(ITS), various cases including autonomous driving, road safety, and traffic
efficiency services have different requirements. For these purposes, latency of
10 - 100 ms with packet loss rate of 10-3 - 10-5 is required. An important
requirement for the utilization of robots and telepresence applications is
remote-control with real-time feedback. System response times must be
less than a few milliseconds including network delays. Communication
infrastructure capable of proving this level of real-time capacity, high
reliability/availability, and mobility support is to be addressed in 5G
networks. In virtual and augmented reality, typical update rates of
display for haptic information and physical simulation are in the order
of 1000 Hz which allows round trip latency of 1 ms. Consistent local
view of VR can be maintained for all users if and only if the latency of
around 1 ms is achieved. In health care, tele-diagnosis and tele-surgery
are probably the most important healthcare applications of low latency
tactile Internet. These allow for remote physical examination, and remote
surgery assisted by robots. Thus, sophisticated control with a round trip
latency of 1 - 10 ms and very high reliability data transmission is crucial.
Smart Grids have strict requirements of reliability and latency. The
dynamic control allows 100 ms of end-to-end latency for switching on or off
suppliers such as PV, windmill, etc. In case of a synchronous co-phasing of
power suppliers such as generators, an end-to-end delay constraint of 1 ms
is required. In education and training, low latency tactile Internet
will assist remote training by haptic overlay of trainers and trainees.
For these identical multi-modal human-machine interfaces, a round trip
latency of 5 - 10 ms is allowed for perceivable visual, auditory, and haptic
From the above, it is clear that providing massive connectivity and also
ultra-reliable and low latency wireless communications will be of major importance
for the future wireless networks.
The International Telecommunication Union (ITU) defined three representative
service categories according to data rates, latency, and reliability .
The enhanced mobile broadband (eMBB), the massive machine-type
communication (mMTC), and the ultra-reliable and low latency communication
Another way to distinguish the traffic is related to the content itself, if it is
reusable or not. For example, voice calls or remote control signals are
not-reusable content. On the other hand, most of the network traffic
today is cacheable or reusable, which is approximately 60%, as stated in
. This is another important aspect that must be taken into account
for the efficient design of networks in order to reduce the unnecessary
transmissions and leave more resources for the non-reusable and critical
content. Thus, Age of Information is expected to play a crucial role in that
2 Long-term objectives of the project
The long term vision of the project is to establish a research group that performs
fundamental research and in parallel can utilize the results into real life networks
through the collaboration with leading industrial partners such as Ericsson. The
goal of the project is to put Link÷ping University on the map for excellent
research in the emerging area of Ultra Reliable and Low Latency Communications
in Wireless Networks and also to establish the project leader and his collaborators
among the world leading experts in this research area. This project will tackle
important theoretical issues that need further investigation and at the same time
these results can be utilized in order to provide solutions that will have
a direct impact on practical wireless networks in the 5G and beyond
A summary of key steps taken towards realizing this vision are given
- The PI has already published a monograph on Age of Information.
- An overview article accepted for publication in IEEE Communications
Magazine considering the role of AoI in Internet of Things.
- Organization of Special Sessions in top-tier IEEE conferences such as
SPAWC 2018 and INFOCOM 2019.
- Editor for IEEE Transactions on Communications and the IEEE Open
Journal of Communications Society.
- Collaborations with top Universities, such as Berkeley, USA, Virginia
Tech., USA, University of Maryland, USA, etc.
3 Current project status and the results that have been achieved
Regarding the research results we have a rich set of publications both in top-tier
journal and conferences as given in the section of publications. All the work
packages progress well, more specifically, the related publications for each WP are
- WP1: Communication Theoretic Principles for uRLLC
- WP2: Proactive Content Placement
- Conferences: [C18,C21]
- WP3: Age of Information - Optimizing Data Freshness
- Journals:[J14, J18, J20, J21, J23]
- Conferences: [C11,C16,C17,C19,C22,C23,C24,C25]
Below we highlight some of the most important findings during 2019. The
works in [J18], [J20], [J21] consider optimal sampling to minimize the Age of
Information in an IoT setup. Furthermore, the work in [C25] is one step closer to
what is called "Effective Age", a metric that can enable context-aware
- Book and Book Chapters
- Z. Chen, N. Pappas, M. Kountouris, “Stochastic Caching Schemes in
Large Wireless Networks", To appear in Wireless Edge Caching, Cambridge
University Press, 2019.
- A. Kosta, N. Pappas, V. Angelakis, “Age of Information: Metric of
Timeliness", Foundations and Trends in Networking: Vol. 12, No. 3. DOI:
- E. Fountoulakis, Qi Liao, N. Pappas, “An End-to-End Performance Analysis
for Service Chaining in a Virtualized Network", Submitted, IEEE Open
Journal of Communications Society, Sep. 2019.
- A. Kosta, N. Pappas, A. Ephremides, V. Angelakis, "The Cost of Delay
in Status Updates and their Value: Non-linear Ageing", Submitted, IEEE
Transactions on Communications, Sep. 2019.
- A. Arvanitaki, N. Pappas, P. Mohapatra, N. Carlsson, "Delay Performance
of a Two-User Broadcast Channel with Security Constraints", Under
Revision, Springer Nature Computer Science, Sep. 2019.
- M. A. Abd-Elmagid, H. S. Dhillon, N. Pappas, “A Reinforcement Learning
Framework for Optimizing Age-of-Information
in RF-powered Communication Systems”, Submitted, IEEE Transactions on
Communications, Aug. 2019.
- G. Stamatakis, N. Pappas, A. Traganitis, “Optimal Policies for Status
Update Generation in an IoT Device with Heterogeneous Traffic", Under
Revision, IEEE Internet of Things Journal, Aug. 2019.
- I. Avgouleas, D. Yuan, N. Pappas, V. Angelakis, “Virtual Network Functions
Scheduling under Delay-Weighted Pricing", Accepted, IEEE Networking
Letters, Aug. 2019.
- M. A. Abd-Elmagid, N. Pappas, H. S. Dhillon, “On the Role of
Age-of-Information in Internet of Things", Accepted, IEEE Communications
Magazine, July 2019.
- N. Pappas, I. Dimitriou, Z. Chen, “On the Benefits of Network-level
Cooperation in IoT Networks with Aggregators", Submitted, IEEE
Transactions on Communications, July 2019.
- I. Dimitriou, N. Pappas, “A Random Access G-Network: Stability,
Stable Throughput, and Queueing Analysis", Accepted, Probability in the
Engineering and Informational Sciences (PEIS), Cambridge University Press,
- C. Tatino, N. Pappas, I. Malanchini, L. Ewe, D. Yuan, “On the Benefits of
Network-Level Cooperation in Millimeter-Wave Communications", Accepted,
IEEE Transactions on Wireless Communications, June 2019.
- A. Kosta,
N. Pappas, A. Ephremides, V. Angelakis, “Age of Information Performance
of Multiaccess Strategies with Packet Management", IEEE/KICS Journal of
Communications and Networks (JCN), June 2019.
- B. Chen, N. Pappas, Z. Chen, D. Yuan, J. Zhang, “Throughput and Delay
Analysis of LWA with Bursty Traffic and Randomized Flow Splitting", IEEE
Access, vol. 7, pp. 24667-24678, 2019.
- B. Chen, L. You, N. Pappas, D. Yuan, “Resource Optimization for
Joint LWA and LAA in Load-coupled and Multi-Cell Networks", IEEE
Communications Letters, vol. 23, no. 2, Feb. 2019.
- N. Pappas, M. Kountouris, “Stable Throughput Region of the Two-User
Interference Channel", Ad Hoc Networks, Vol. 85, Mar. 2019.
- O. Holland, E. Steinbach, V. Prasad, Q. Liu, Z. Dawy, A. Aijaz, N. Pappas,
K. Chandra, V. Rao, S. Oteafy, M. Eid, M. Luden, A. Bhardwaj, X. Liu,
J. Sachs, J. Araujo, “The IEEE 1918.1 “Tactile Internet” Standards Working
Group and its Standards", Proceedings of the IEEE, vol. 107, no. 2, pp.
256-279, Feb. 2019.
- I. Dimitriou, N. Pappas, “Performance Analysis of a Cooperative Wireless
Network with Adaptive Relays", Ad Hoc Networks, Ad Hoc Networks, Vol.
87, May 2019.
- A. Aijaz, Z. Dawy, N. Pappas, S. Oteafy, M. Simsek, O. Holland, “Toward
a Tactile Internet Reference Architecture: Vision and Progress of the IEEE
P1918.1 Standard", Submitted, IEEE Communications Standards Maganize,
- L. You, Q. Liao, N. Pappas, D. Yuan, “Resource Optimization with
Flexible Numerology and Frame Structure for Heterogeneous Services", IEEE
Communications Letters, vol. 22, no. 12, Dec. 2018.
- Z. Chen, N. Pappas, M. Kountouris and V. Angelakis, “Throughput with
Delay Constraints in a Shared Access Network with Priorities", IEEE
Transactions on Wireless Communications, vol. 17, no. 9, Sept. 2018.
- N. Pappas, M. Kountouris, A. Ephremides, V. Angelakis, “Stable
Throughput Region of the Two-user Broadcast Channel", IEEE Transactions
on Communications, vol. 66, no. 10, Oct. 2018.
- P. Mohapatra, N. Pappas, J. Lee, T. Q. S. Quek, V. Angelakis, "Secure
Communications for the Two-user Broadcast Channel with Random Traffic",
IEEE Transactions on Information Forensics & Security, vol. 13, no. 9, Sept.
- I. Dimitriou, N. Pappas, “Stable Throughput and Delay Analysis of
a Random Access Network With Queue-Aware Transmission". IEEE
Transactions on Wireless Communications, vol. 17, no. 5, pp. 3170-3184,
- N. Pappas, Z. Chen, I. Dimitriou, “Throughput and Delay Analysis of
Wireless Caching Helper Systems with Random Availability", IEEE Access,
vol. 6, 2018.
- N. Pappas, J. Jeon, Di Yuan, A. Traganitis, A. Ephremides, “Wireless
Network-Level Partial Relay Cooperation: A Stable Throughput Analysis",
IEEE/KICS Journal of Communications and Networks (JCN), vol. 20, no.
1, Feb. 2018.
- G. Stamatakis, N. Pappas, A. Traganitis, “Control of Status Updates for
Energy Harvesting Devices that Monitor Processes with Alarms", IEEE
GLOBECOM Workshops, Dec. 2019.
- M. A. Abd-Elmagid, H. S. Dhillon, N. Pappas, “Online
Age-minimal Sampling Policy for RF-powered IoT Networks", IEEE Global
Communications Conference (GLOBECOM), Dec. 2019.
- G. Stamatakis, N. Pappas, A. Traganitis, “Controlling Status Updates in
a Wireless System with Heterogeneous Traffic and AoI Constraints", IEEE
Global Communications Conference (GLOBECOM), Dec. 2019.
- M. Moltafet, M. Leinonen, M. Codreanu, N. Pappas, “Power Minimization in
Wireless Sensor Networks With Constrained AoI: Stochastic Optimization",
Asilomar Conference on Signals, Systems, and Computers, Nov. 2019.
- I. Avgouleas, N. Pappas, V. Angelakis, “Performance Evaluation of Wireless
Caching Helper Systems", 15th International Conference on Wireless and
Mobile Computing, Networking and Communications (WiMob), Oct. 2019.
- E. Fountoulakis, Q. Liao, M. Stein, N. Pappas, “Traversing Virtual Network
Functions from the Edge to the Core: An End-to-End Performance Analysis",
16th International Symposium on Wireless Communication System (ISWCS),
- N. Pappas, M.
Kountouris, “Delay Violation Probability and Age-of-information Interplay in
the Two-user Multiple Access Channel", IEEE 20th International Workshop
on Signal Processing Advances in Wireless Communications (SPAWC), July
- A. Kosta, N. Pappas, A. Ephremides, V. Angelakis, “Queue Management
for Age Sensitive Status Updates", IEEE International Symposium on
Information Theory (ISIT), July 2019.
- Z. Chen, N. Pappas, E. Bj÷rnson, E. G. Larsson, “Age of Information
in a Multiple Access Channel with Heterogeneous Traffic and an Energy
Harvesting Node", IEEE INFOCOM Workshops - 2nd Age of Information
Workshop, April 2019.
- N. Nomikos., T. Charalambous, N. Pappas, D. Vouyioukas, R. Wichman,
“LoLA4SOR: A Low-Latency Algorithm for Successive Opportunistic
Relaying", IEEE INFOCOM Workshops - Ultra-Low Latency in Wireless
Networks Workshop, April 2019.
- I. Dimitriou, N. Pappas, “A Queue-based Random Access Scheme
in Network-level Cooperative Wireless Networks", IEEE International
Conference on Communications (ICC), May 2019.
- B. Chen, N. Pappas, Z. Chen, D. Yuan, J. Zhang, “LTE-WLAN
Aggregation with Bursty Data Traffic and Randomized Flow Splitting", IEEE
International Conference on Communications (ICC), May 2019.
- E. Fountoulakis, N. Pappas, Q. Liao, A. Ephremides, V. Angelakis,
“Dynamic Power Control for Packets with Deadlines", IEEE Global
Communications Conference (GLOBECOM), Dec. 2018.
- A. Kosta, N. Pappas, A. Ephremides, V. Angelakis, “Age of Information
and Throughput in a Shared Access Network with Heterogeneous Traffic",
IEEE Global Communications Conference (GLOBECOM), Dec. 2018.
- N. Daneshfar, N. Pappas, V. Polishchuk, V. Angelakis, “Service Allocation
in a Mobile Fog Infrastructure under Availability and QoS Constraints", IEEE
Global Communications Conference (GLOBECOM), Dec. 2018.
- C. Tatino, N. Pappas, I. Malanchini, L. Ewe, D. Yuan, “Throughput Analysis
for Relay-Assisted Millimeter-Wave Wireless Networks", IEEE GLOBECOM
Workshops, Dec. 2018.
- A. Arvanitaki, N. Pappas, P. Mohapatra, N. Carlsson, “Delay Performance
of a Two-User Broadcast Channel with Security Constraints", Global
Information Infrastructure and Networking Symposium (GIIS), Oct. 2018.
- N. Pappas, I. Dimitriou, Z. Chen, “Network-level Cooperation in Random
Access IoT Networks with Aggregators", International Teletraffic Congress
(ITC 30), Sept. 2018.
- B. Chen, Z. Chen, N. Pappas, D. Yuan, J. Zhang, “Bringing LTE to
Unlicensed Spectrum: Technical Solutions and Deployment Considerations",
IEEE International Workshop on Computer Aided Modeling and Design of
Communication Links and Networks (CAMAD), Sept. 2018.
- N. Pappas, “Performance Analysis of a System with Bursty Traffic and
Adjustable Transmission Times", 15th International Symposium on Wireless
Communication System (ISWCS), Aug. 2018.
- N. Nomikos, N. Pappas, T. Charalambous, Y. A. Pignolet,
“Deadline-constrained Bursty Traffic in Random Access Wireless Networks",
IEEE 19th International Workshop on Signal Processing Advances in Wireless
Communications (SPAWC), June 2018.
- M. Kountouris, N. Pappas, A. Avranas, “QoS Provisioning in Large Wireless
Networks", 16th International Symposium on Modeling and Optimization in
Mobile, Ad Hoc, and Wireless Networks (WiOpt), May 2018.
- C. Tatino, I. Malanchini, N. Pappas, D. Yuan, “Maximum Throughput
Scheduling for Multi-connectivity in Millimeter-Wave Networks", 16th
International Symposium on Modeling and Optimization in Mobile, Ad Hoc,
and Wireless Networks (WiOpt), May 2018.
- I. Dimitriou, N. Pappas, “Performance Analysis of an Adaptive
Two-user Random Access Scheme", IEEE International Conference on
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