arXiv subjects

Abhay Karandikar

Publications and source records attributed to Abhay Karandikar.

At least 19 recordsLinked to original sources

arXiv2025

ITU-T Y.2325: NGN Evolution Towards Future

International Telecommunications Union (ITU) defined Next Generation Network (NGN) underlies most wireline and wireless packet-based telecommunications networks. A key design principle of NGN is decoupling of service-related functions from the underlying transport stratum, making user services independent of transport technologies. Interestingly, the NGN architecture, as defined in ITU standards, did not follow this design principle for internal network services, e.g., mobility, or authentication though adhering for external user services like IPTV or Multimedia services. These internal services are handled by the NGN transport control plane, making them an intrinsic part of the transport stratum, resulting in a tightly coupled service and transport functionality as opposed to the proclaimed design goal. This design choice may force each transport technology to support internal services individually, e.g., separate authentication service for each transport, leading to duplication. Since the NGN architecture is the base underlying architecture for most packet-based telecommunications network including advanced cellular networks like 4th/5th Generation cellular networks, the limitation persists in these cellular networks as well. To remedy the situation, the decoupling of service and transport can be generalized to include internal services like mobility and authentication also. In this context, the recently published ITU Y.2325 recommendation, defines an evolved NGN architecture, wherein all services, including internal network services, are decoupled from the transport stratum. The proposal results in a more scalable and modular evolved NGN architecture that can be used as a template for all future telecom networks including IMT-2030 (6th generation mobile networks). In this article, we review the evolved NGN architecture, as proposed in ITU-T Y.2325.

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arXiv2024

Applying SDN to Mobile Networks: A New Perspective for 6G Architecture

The upcoming Sixth Generation (6G) mobile communications system envisions supporting a variety of use cases with differing characteristics, e.g., very low to extremely high data rates, diverse latency needs, ultra massive connectivity, sustainable communications, ultra-wide coverage etc. To accommodate these diverse use cases, the 6G system architecture needs to be scalable, modular, and flexible; both in its user plane and the control plane. In this paper, we identify some limitations of the existing Fifth Generation System (5GS) architecture, especially that of its control plane. Further, we propose a novel architecture for the 6G System (6GS) employing Software Defined Networking (SDN) technology to address these limitations of the control plane. The control plane in existing 5GS supports two different categories of functionalities handling end user signalling (e.g., user registration, authentication) and control of user plane functions. We propose to move the end-user signalling functionality out of the mobile network control plane and treat it as user service, i.e., as payload or data. This proposal results in an evolved service-driven architecture for mobile networks bringing increased simplicity, modularity, scalability, flexibility and security to its control plane. The proposed architecture can also support service specific signalling support, if needed, making it better suited for diverse 6GS use cases. To demonstrate the advantages of the proposed architecture, we also compare its performance with the 5GS using a process algebra-based simulation tool.

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arXiv2024

A Flexible Architecture for Broadcast Broadband Convergence in Beyond 5G

There has been an exponential increase in the usage of multimedia services in mobile networks in recent years. To address this accelerating data demand, mobile networks are experiencing a subtle transformation in their architecture. One of the changes in this direction is the support of Multicast/Broadcast Service (MBS) in the Third Generation Partnership Project (3GPP) Fifth Generation (5G) network. The MBS has been introduced to enhance resource utilization and user experience in 3GPP 5G networks. However, there are certain limitations in the 3GPP 5G MBS architecture, such as the selection of the delivery method (unicast or broadcast) by the core network (may result in sub-optimal radio resource utilization) and no provision for converging non-3GPP broadcast technologies (like digital terrestrial television) with cellular (3GPP 5G) broadband. In this context, we propose a new architecture for the convergence of cellular broadband and non-3GPP broadcast networks. A novelty of the architecture is that it treats signalling exchange with User Equipment (UE) as data (service) which results in improved scalability of mobile networks. The architecture supports enhanced flexibility in choosing a delivery method (3GPP 5G unicast, 3GPP 5G broadcast, or non-3GPP broadcast) for user data. We evaluate the performance of the proposed architecture using process algebra-based simulations, demonstrating a significant reduction in the number of signalling messages exchanged between the UE and the network for MBS session establishment as compared to the 3GPP 5G network.

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arXiv2023

An Architecture for Control Plane Slicing in Beyond 5G Networks

To accommodate various use cases with differing characteristics, the Fifth Generation (5G) mobile communications system intends to utilize network slicing. Network slicing enables the creation of multiple logical networks over a shared physical network infrastructure. While the problems such as resource allocation for multiple slices in mobile networks have been explored in considerable detail in the existing literature, the suitability of the existing mobile network architecture to support network slicing has not been analysed adequately. We think the existing 5G System (5GS) architecture suffers from certain limitations, such as a lack of slice isolation in its control plane. This work focuses on the future evolution of the existing 5GS architecture from a slicing perspective, especially that of its control plane, addressing some of the limitations of the existing 5GS architecture. We propose a new network architecture which enables efficient slicing in beyond 5G networks. The proposed architecture results in enhanced modularity and scalability of the control plane in sliced mobile networks. In addition, it also brings slice isolation to the control plane, which is not feasible in the existing 5G system. We also present a performance evaluation that confirms the improved performance and scalability of the proposed system viz a viz the existing 5G system.

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arXiv2023

Multi-Connectivity for Multicast Video Streaming in Cellular Networks (Extended Abstract)

In video streaming applications especially during live streaming events (such as the Super Bowl), video traffic can account for a significant portion of network traffic and can lead to severe network congestion. During such events, multicast transmission can be used to avoid network congestion since the same video content is being streamed to multiple users simultaneously. However, providing seamless connectivity to cellular users in multicast streaming remains an open problem. To address this issue, this paper explores the potential of using multi-connectivity (MC) in wireless multicast streaming. Our results reveal that MC significantly improves the performance of multicast services, especially for cell edge users who often suffer from poor channel conditions. We prove that optimal resource allocation in MC multicast streaming is an NP-hard problem. Therefore, we propose a greedy approximation algorithm for this problem with an approximation factor of $(1-1/e)$. We also prove that no other polynomial-time algorithm can provide a better approximation.

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arXiv2022

Leveraging Multi-Connectivity for Multicast Video Streaming

Multi-connectivity has emerged as a key enabler for providing seamless connectivity in cellular mobile networks. However, its potential for improving the quality of multicast transmissions has remained unexplored. In this paper, we investigate the use of multi-connectivity in wireless multicast streaming. Multi-connectivity can significantly improve the performance of multicast services. It especially benefits the cell edge users who often suffer from poor channel conditions. In this work, we assess the impact of multi-connectivity on the performance of multicast streaming. We propose procedures for establishing multi-connectivity in a multicast system and address the associated resource allocation problem. We prove that the optimal resource allocation problem is NP-hard. We propose a greedy approximation algorithm for this problem and prove that no other polynomial-time algorithm can provide a better approximation. Since video streaming is the primary use case under consideration here, we use traces from actual videos to generate realistic video traffic patterns in our simulations. Our simulation results clearly establish that multi-connectivity results in considerable performance improvement in multicast streaming.

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arXiv2022

A Flexible IAB Architecture for Beyond 5G Network

IAB is an innovative wireless backhaul solution to provide cost-efficient deployment of small cells for successful 5G adoption. Besides, IAB can utilize the same spectrum for access and backhaul purposes. The 3GPP standardized IAB in Release 16 and would incorporate a few enhancements in the upcoming releases. The 3GPP IAB architecture, however, suffers from some limitations, such as it does not support mobile relays or dual-connectivity. This article presents a novel IAB architecture that addresses these limitations and is transparent to legacy operations of the 5G system. The architecture also supports multi-RAT coexistence where access and backhaul may belong to different RATs. These factors (and many others) enable operators to capitalize on the architecture for deploying IAB anywhere in a plug-and-play manner. We also show the merits of the architecture by evaluating its capacity and mobility robustness compared to the 3GPP architecture. Simulation results corroborate our design approach. Owing its robust design, the architecture can contend for standardization in B5G system.

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arXiv2021

Online Reinforcement Learning of Optimal Threshold Policies for Markov Decision Processes

To overcome the curses of dimensionality and modeling of Dynamic Programming (DP) methods to solve Markov Decision Process (MDP) problems, Reinforcement Learning (RL) methods are adopted in practice. Contrary to traditional RL algorithms which do not consider the structural properties of the optimal policy, we propose a structure-aware learning algorithm to exploit the ordered multi-threshold structure of the optimal policy, if any. We prove the asymptotic convergence of the proposed algorithm to the optimal policy. Due to the reduction in the policy space, the proposed algorithm provides remarkable improvements in storage and computational complexities over classical RL algorithms. Simulation results establish that the proposed algorithm converges faster than other RL algorithms.

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arXiv2020

5G-Flow: Flexible and Efficient 5G RAN Architecture Using OpenFlow

Convergence of multiple access technologies is one of the key enablers in providing a diverse set of services to the Fifth Generation (5G) users. Though the 3rd Generation Partnership Project (3GPP) 5G standard defines a common core supporting multiple Radio Access Technologies (RATs), Radio Access Network (RAN) level decisions are taken separately across individual RATs as the existing 5G architecture lacks a unified control and management framework for a multi-RAT network. A unified access network is likely to utilize RAN resources more efficiently and provide an improved performance. To bridge these gaps, we present an OpenFlow based RAN architecture comprising multiple RATs. We refer to it as \textit{5G-Flow}. With minimal changes in the 3GPP 5G RAN and none in the core network, we are able to realize a unified and integrated multi-access 5G-Flow RAN. We simplify the existing 3GPP 5G RAN by replacing RAN nodes with OpenFlow switches and a Software-Defined Networking (SDN) controller. Moreover, a UE in the 5G-Flow network can use 5G RAN to connect to any core network (4G or 5G) or directly connect to Internet without going via the core network. We also present a simple method to realize 5G non-standalone architecture using 5G-Flow RAN. We have developed an evaluation platform to compare the performance of our architecture with the standard 3GPP 5G network. Results demonstrate significant gains in the network performance of 5G-Flow RAN architecture over the existing 3GPP 5G network.

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arXiv2020

Proportional Fairness through Dual Connectivity in Heterogeneous Networks

Proportional Fair (PF) is a scheduling technique to maintain a balance between maximizing throughput and ensuring fairness to users. Dual Connectivity (DC) technique was introduced by the 3rd Generation Partnership Project (3GPP) to improve the mobility robustness and system capacity in heterogeneous networks. In this paper, we demonstrate the utility of DC in improving proportional fairness in the system. We propose a low complexity centralized PF scheduling scheme for DC and show that it outperforms the standard PF scheduling scheme. Since the problem of dual association of users for maximizing proportional fairness in the system is NP-hard, we propose three heuristic user association schemes for DC. We demonstrate that DC, along with the proposed PF scheme, gives remarkable gains on PF utility over single connectivity and performs almost close to the optimal PF scheme in heterogeneous networks.

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arXiv2020

Open5G: A Software-Defined Networking Protocol for 5G Multi-RAT Wireless Networks

Mobile Networks today comprise of multiple Radio Access Technologies (RATs), e.g., 4G LTE, Wireless Local Area Network (WLAN), and the upcoming 5G-New Radio (5G-NR). The access networks of these RATs are controlled by RAT-specific entities, e.g., the resource management function located inside an individual LTE eNB is used for the eNB control, or access controllers are used for controlling WLAN Access Points. Even in the 3GPP's 5G architecture, which has a common Core supporting multiple RATs, radio access related decisions are taken independently within individual RATs. Due to the fragmented nature of control-plane in multi-RAT Radio Access Network (RAN), a unified global view of network resources is unavailable, hindering optimized allocation of resources. It also brings complexity to the features involving multiple RATs, e.g., dual connectivity. To address these issues, we introduced an SDN-based Multi-RAT RAN architecture (SMRAN) in our earlier work [arXiv:1812.11825], where the RAN control-plane is segregated from the data-plane. As part of the SMRAN architecture, we defined a logically centralized multi-RAT RAN Controller and individual RAT-specific data-plane functions. In the current work, we define a protocol, called Open5G, to be used for control and management of the SMRAN data-plane. Open5G is based on OpenFlow (OF) and OF-Config, which are commonly used protocols in the SDN-based wired networks and data centers.

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arXiv2020

Strategy-Proof Spectrum Allocation among Multiple Operators for Demand Varying Wireless Networks

To address the exponentially increasing data rate demands of end users, necessitates efficient spectrum allocation among co-existing operators in licensed and unlicensed spectrum bands to cater to the temporal and spatial variations of traffic in the wireless network. In this paper, we address the spectrum allocation problem among non-cooperative operators via auctions. The classical Vickrey-Clarke-Groves (VCG) approach provides the framework for a strategy-proof and social welfare maximizing auction at high computational complexity, which makes it infeasible for practical implementation. We propose sealed bid auction mechanisms for spectrum allocation which are computationally tractable and hence applicable for allocating spectrum by performing auctions in short durations as per the dynamic load variations of the network. We establish that the proposed algorithm is strategy-proof for uniform demand. Furthermore, for non-uniform demand we propose an algorithm that satisfies weak strategy-proofness. We also consider non-linear increase in the marginal valuations with demand. Simulation results are presented to exhibit the performance comparison of the proposed algorithms with VCG and other existing mechanisms.

cs.GT↗

arXiv2019

Realizing the Frugal 5G Network

In order to make effective use of the Internet, broadband connectivity is a pre-requisite. However, in the majority of rural areas in developing countries, high-speed connectivity is unavailable. The Frugal 5G network architecture presented in this paper aims at enabling broadband in rural areas by addressing the challenges associated with it. The work presented in this paper is a development over our previous work, in which we proposed abstract network architecture for Frugal 5G. In this paper, we provide an innovative solution to realize the Frugal 5G network. We identify the key system requirements and show that the proposed solution enables an uncomplicated and flexible realization of the Frugal 5G network. We are currently building a testbed to implement the proposed changes.

cs.NI↗

arXiv2019

Performance and Energy Conservation of 3GPP IFOM Protocol for Dual Connectivity in Heterogeneous LTE-WLAN Network

For the 5th Generation (5G) networks, Third Generation Partnership Project (3GPP) is considering standardization of various solutions for traffic aggregation using licensed and unlicensed spectrum, to meet the rising data demands. IP Flow Mobility (IFOM) is a multi access connectivity solution/protocol standardized by the Internet Engineering Task force (IETF) and 3GPP in Release 10. It enables concurrent access for an User Equipment (UE) to Heterogeneous Networks (HetNets) such as Long Term Evolution (LTE) and IEEE 802.11 Wireless Local Area Network (WLAN). IFOM enabled UEs have multiple interfaces to connect to HetNets. They can have concurrent flows with different traffic types over these networks and can seamlessly switch the flows from one network to the other. In this paper, we focus on two objectives. First is to investigate the performance parameters e.g. throughput, latency, tunnelling overhead, packet loss, energy cost etc. of IFOM enabled UEs (IeUs) in HetNets of LTE and WLAN. We have proposed a novel mechanism to maximize the throughput of IeUs achieving a significant throughput gain with low latency for the IeUs. We have explored further and observed a throughput energy trade off for low data rate flows. To address this, we also propose a smart energy efficient and throughput optimization algorithm for the IeUs, resulting in a substantial reduction in energy cost, while maintaining the high throughput at lower latency and satisfying the Quality of Service (QoS) requirements of the IeUs.

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arXiv2019

Resource Allocation for Loss Tolerant Video Streaming in eMBMS

Bandwidth hungry video content has become the dominant contributor to the data traffic world over. Cellular networks are constantly evolving to meet the growing traffic demands. Over the past few years, wireless multicast has been garnering a lot of attention as a means of efficient resource utilization. Multicast transmission lets spectral resources to be shared between users streaming the same content. Even though multicast transmission allows to serve multiple users on the same resources, in order to serve all these users successfully, the base station cannot transmit the content at a rate greater than that decodable by the user with the worst channel conditions. In this paper, we propose a way to overcome this bottleneck. Video streaming services can sustain a certain amount of packet loss without any significant degradation in the quality experienced by the users. We leverage this loss tolerant nature of video streaming applications to improve the performance of multicast video services in LTE and 5G. We convert the problem of resource allocation for loss tolerant multicasting into the problem of stabilizing a queueing system. We then propose two throughput optimal Maximum Weight (MW) policies that successfully stabilize the constructed queueing system. However, brute force implementation of MW policies is mostly NP-hard. To overcome this, we propose a maximum weight bipartite matching approach that results in a polynomial time implementation of the proposed policies. We also evaluate the performance of our policies via extensive simulations.

cs.NI↗

arXiv2019

Connecting the Unconnected: Towards Frugal 5G Network Architecture and Standardization

This article adopts a holistic approach to address the problem of poor broadband connectivity in rural areas by suggesting a novel wireless network architecture, also called the "Frugal 5G Network". To arrive at the Frugal 5G Network architecture, we take into consideration the rural connectivity needs and the characteristics specific to rural areas. As part of the proposed Frugal 5G Network, we define a heterogeneous Access Network wherein macro cells provide a carpet coverage while Wireless Local Area Networks (WLANs) provide additional capacity to serve the village clusters. WLAN is backhauled via a wireless network also called the wireless middle mile network. We define a Software Defined Networking (SDN) and Network Function Virtualization (NFV) based architecture to make the network flexible and scalable. The concepts of Fog computing have also been employed in the network architecture to bring intelligence to the edge, i.e., to the access network. Through a novel amalgamation of these technologies, we are able to address the connectivity requirements of rural areas. The proposed network architecture can serve as a potential solution towards IEEE P2061, a standardization project that aims to design an architecture to facilitate rural broadband communication.

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arXiv2018

Multi-Player Multi-Armed Bandit Based Resource Allocation for D2D Communications

Device-to-device (D2D) communications is expected to play a significant role in increasing the system capacity of the fifth generation (5G) wireless networks. To accomplish this, efficient power and resource allocation algorithms need to be devised for the D2D users. Since the D2D users are treated as secondary users, their interference to the cellular users (CUs) should not hamper the CU communications. Most of the prior works on D2D resource allocation assume full channel state information (CSI) at the base station (BS). However, the required channel gains for the D2D pairs may not be known. To acquire these in a fast fading channel requires extra power and control overhead. In this paper, we assume partial CSI and formulate the D2D power and resource allocation problem as a multi-armed bandit problem. We propose a power allocation scheme for the D2D users in which the BS allocates power to the D2D users if a certain signal-to-interference-plus-noise ratio (SINR) is maintained for the CUs. In a single player environment a D2D user selects a CU in every time slot by employing UCB1 algorithm. Since this resource allocation problem can also be considered as an adversarial bandit problem we have applied the exponential-weight algorithm for exploration and exploitation (Exp3) to solve it. In a multiple player environment, we extend UCB1 and Exp3 to multiple D2D users. We also propose two algorithms that are based on distributed learning algorithm with fairness (DLF) and kth-UCB1 algorithms in which the D2D users are ranked. Our simulation results show that our proposed algorithms are fair and achieve good performance.

cs.NI↗

arXiv2018

Control and Management of Multiple RATs in Wireless Networks: An SDN Approach

Telecom operators are using a variety of Radio Access Technologies (RATs) for providing services to mobile subscribers. This development has emphasized the requirement for unified control and management of diverse RATs. Although multiple RATs co-exist within today's cellular networks, each RAT is controlled by a set of different entities. This may lead to suboptimal utilization of the overall network resources. In this article, we review various architectures for multi-RAT control proposed by both industry and academia. We also propose a novel SDN based network architecture for end-to-end control and management of diverse RATs. The architecture is scalable and provides a framework for improved network performance over the present day architecture and proposals in existing literature. Our architecture also provides a framework for deployment of applications in a RAT agnostic fashion. It facilitates network slicing and enables the provision of Quality of Service (QoS) guarantees to the end user. We have also developed an evaluation platform based on ns-3 to evaluate the performance offered by the architecture. Experimental results obtained using the platform demonstrate the benefits provided by our architecture.

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