Design and Service Provisioning Methods for Optical Networks in 5G and Beyond Scenarios
Doctoral thesis, 2023

Network operators are deploying 5G while also considering the evolution towards 6G. They consider different enablers and address various challenges. One trend in the 5G deployment is network densification, i.e., deploying many small cell sites close to the users, which need a well-designed transport network (TN). The choice of the TN technology and the location for processing the 5G protocol stack functions are critical to contain capital and operational expenditures. Furthermore, it is crucial to ensure the resiliency of the TN infrastructure in case of a failure in nodes and/or links while the resource efficiency is maximized.

Operators are also interested in 5G networks with flexibility and scalability features. In this context, one main question is where to deploy network functions so that the connectivity and compute resources are utilized efficiently while meeting strict service latency and availability requirements. Off-loading compute resources to large and central data centers (DCs) has some advantages, i.e., better utilization of compute resources at a lower cost. A backup path can be added to address service availability requirements when using compute off-loading strategies. This might impact the service blocking ratio and limit operators’ profit. The importance of this trade-off becomes more critical with the emergence of new 6G verticals.

This thesis proposes novel methods to address the issues outlined above. To address the challenge of cost-efficient TN deployment, the thesis introduces a framework to study the total cost of ownership (TCO), latency, and reliability performance of a set of TN architectures for high-layer and low-layer functional split options. The architectural options are fiber- or microwave-based. To address the strict availability requirement, the thesis proposes a resource-efficient protection strategy against single node/link failure of the midhaul segment. The method selects primary and backup DCs for each aggregation node (i.e., nodes to which cell sites are connected) while maximizing the sharing of backup resources. Finally, to address the challenge of resource efficiency while provisioning services, the thesis proposes a backup-enhanced compute off-loading strategy (i.e., resource-efficient provisioning (REP)). REP selects a DC, a connectivity path, and (optionally) a backup path for each service request with the aim of minimizing resource usage while the service latency and availability requirements are met.

Our results of the techno-economic assessment of the TN options reveal that, in some cases, microwave can be a good substitute for fiber technology. Several factors, including the geo-type, functional split option, and the cost of fiber trenching and microwave equipment, influence the effectiveness of the microwave. The considered architectures show similar latency and reliability performance and meet the 5G service requirements. The thesis also shows that a protection strategy based on shared connectivity and compute resources can lead to significant cost savings compared to benchmarks based on dedicated backup resources. Finally, the thesis shows that the proposed backup-enhanced compute off-loading strategy offers advantages in service blocking ratio and profit gain compared to a conventional off-loading approach that does not add a backup path. Benefits are even more evident considering next-generation services, e.g., expected on the market in 3 to 5 years, as the demand for services with stringent latency and availability will increase.



functional split

optical network design


network control and management




5G and beyond

Room HC2, E2 Department, Hörsalsvägen 14, Chalmers
Opponent: Professor Daniel Kilper, Trinity College Dublin, Ireland


Maryam Lashgari

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

Fiber- vs. Microwave-based 5G Transport: a Total Cost of Ownership Analysis

European Conference on Optical Communication, ECOC,; (2022)

Paper in proceeding

Techno-economics of Fiber vs. Microwave for Mobile Transport Network Deployments [Invited]

Journal of Optical Communications and Networking,; Vol. 15(2023)p. C74-C87

Journal article

Techno-economics of 5G transport deployments

Proceedings of SPIE - The International Society for Optical Engineering,; Vol. 12429(2023)

Paper in proceeding

A Shared-Path Shared-Compute Planning Strategy for a Resilient Hybrid C-RAN

International Conference on Transparent Optical Networks,; Vol. 2019-July(2019)

Paper in proceeding

Cost Benefits of Centralizing Service Processing in 5G Network Infrastructures

Optics InfoBase Conference Papers,; (2019)

Paper in proceeding

End-to-End Provisioning of Latency and Availability Constrained 5G Services

IEEE Communications Letters,; Vol. 25(2021)p. 1857-1861

Journal article

M. Lashgari, F. Tonini, L. Wosinska, L. M. Contreras, and P. Monti, "Next-Generation Service Deployment with Compute Off- Loading: a Profit Analysis Perspective"

5G is the latest generation of mobile network technology, offering higher speed, lower latency, and more reliable communication than the previous generations. Network operators and the research community are already discussing 6G, which is expected to support higher traffic demand and reliability performance than 5G. 6G will bring a new level of connectivity to our lives by offering services such as virtual reality, holographic communication, ubiquitous intelligence, and immersive online games. These services have the extremely challenging capacity, latency, and reliability requirements.

Deploying networks for 5G and beyond services require investments in new or upgraded infrastructures. Therefore, finding an option with an acceptable compromise between cost and performance is crucial. This can be achieved by evaluating the cost, latency, and reliability performance of various network deployment solutions.

Another essential aspect is network resiliency. As many devices and critical applications rely on 5G networks, the failures of nodes and/or links may have serious consequences. Designing a resilient 5G network is crucial to minimize service downtime. This can be achieved using backup solutions leveraging the redundancy of resources. However, deploying additional backup resources into the network may increase the cost. For this reason, efficient protection strategies using as few redundant resources as possible are needed.

Finally, resources in a 5G/6G network must be utilized efficiently to support as many services as possible. Operators can then cater to many users and increase their profit. Optimal resource utilization is even more critical with the emergence of new 6G services with stringent latency and availability constraints. Hence, operators seek resource-efficient service provisioning methods to maximize their profit while meeting service requirements.

This thesis first proposes solutions to deploy cost-efficient network infrastructures to address the challenges mentioned above. Then, it develops 5G/6G service provisioning methods to optimize the number of served users and operators’ profit.

Automation of Network edge Infrastructure & Applications with aRtificiAl intelligence, ANIARA

VINNOVA (2020-00763), 2020-06-15 -- 2023-10-31.

Providing Resilient & secure networks [Operating on Trusted Equipment] to CriTical infrastructures (PROTECT)

VINNOVA (2020-03506), 2021-02-01 -- 2024-01-31.

Smart City Concepts in Curitiba - low-carbon transport and mobility in a digital society

VINNOVA (2019-04893), 2019-12-01 -- 2023-05-31.

5G System Technological Enhancements Provided by Fiber Wireless Deployments

European Commission (EC) (EC/H20207224295), 2017-06-01 -- 2020-05-31.

European Commission (EC) (EC/H20207224295), 2017-06-01 -- 2022-03-31.

Areas of Advance

Information and Communication Technology

Driving Forces

Sustainable development

Subject Categories


Electrical Engineering, Electronic Engineering, Information Engineering

Other Electrical Engineering, Electronic Engineering, Information Engineering


C3SE (Chalmers Centre for Computational Science and Engineering)



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5307



Room HC2, E2 Department, Hörsalsvägen 14, Chalmers

Opponent: Professor Daniel Kilper, Trinity College Dublin, Ireland

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