LTE Architecture Research Articles

Design of Elastic Call Admission Control in Tidal Load Scenario for Cloud-based Cellular Networks

Cellular networks have witnessed an unprecedented expansion represented by the number of subscribers in addition to the unlimited number of applications. In the era of IoT, connections may involve machines working side by side with humans on the same network. Tidal load is one of the key challenges in mobile networks, which represents a temporary phenomenon resulting from increasing traffic volumes at certain times of the day in particular places. This leads to the problem of overutilization of some base stations, particularly in fixed resources allocation systems such as 4G LTE architecture, which contains physically separated base stations. This results in increasing the dropping and blocking probability for the incoming calls in an overloaded area, while others suffer from underutilization or might be almost idle for a particular time. In this paper, an Elastic Call Admission Control (ECAC) approach is proposed to reduce the probability of blocking and dropping to improve the network performance in the tidal load scenario. This is achieved using the concept of gain multiplexing technique and cloud-based cellular architecture for utilizing the shared available recourses of the co-located virtual base stations in the cloud. A Fuzzy Type 2 (FT2) system is used to maintain the switching decision for resource sharing mode, the network load is predicted in advance using Gaussian Process Regression (GPR) model. Performance evaluation is carried out using the cloud-based Fog-Radio Access Network (F-RAN) platform. Compared to legacy LTE architecture, the results illustrate a noticeable enhancement in terms of minimizing blocking probability, enhancing overall network performance represented by network data throughput, and network utilization.

Integrated LTE and Wi-Fi Network Architecture with Authentication of User Equipment for Dropping off the Surplus Load of LTE

Integrated LTE and Wi-Fi Network Architecture with Authentication of User Equipment for Dropping off the Surplus Load of LTE

CleanG—Improving the Architecture and Protocols for Future Cellular Networks With NFV

With the rapid increase in the number of users and changing pattern of network usage, cellular networks will continue to be challenged meeting bandwidth and latency requirements. A significant contributor to latency and overhead is cellular network’s complex control-plane. We propose CleanG, a new packet core architecture and significantly more efficient control-plane protocol, that exploits the capabilities of modern-day Network Function Virtualization (NFV) platforms. CleanG is a single component NFV-based architecture. With the elastic scalability offered by NFV, the data and control sub-components of the core can scale, adapting to workload demand. CleanG eliminates the use of GTP tunnels for data packets and the associated complex protocol for coordination across multiple, distributed components for setting up and managing them. We carefully examine the use of each protocol message exchange (and the component fields of those messages) in developing a substantially simplified protocol, while retaining similar essential functionality for security, mobility, and air-interface resource management. We have implemented CleanG on the OpenNetVM platform and perform an apples-to-apples comparison with the existing 3GPP LTE architecture and an architecture that separates the control and user plane (the CUPS-based architecture like the 5G architecture). Measurements on our testbed show that CleanG substantially reduces both control and data plane latency, and significantly increases system capacity.

Software‐defined networking to improve handover in mobile edge networks

SummaryMobility management and handover for a seamless connection are among all‐time challenges of wireless networks. Software‐defined networking (SDN) has opened new horizons toward research by adding intelligence in edge networks while decoupling the control and data planes. The flexibility and centralized nature of SDN further improve the handover decision algorithms. In this paper, we have improved the network performance with respect to the number of handovers and the handover delay by applying an LTE‐SDN architecture and a novel handover decision algorithm based on predicting the future locations of a moving vehicle. The proposed algorithm decouples the handover procedure into two phases of preparation and execution. In the preparation phase, which occurs in the control plane, the handover decision and resource allocation take place, and in the execution phase, handover gets executed similar to the LTE architecture. The results of our research indicate that our proposed LTE‐SDN performance is improved with respect to the number of handovers, handover delay, and signaling overhead by 24%, 16%, and 20%, respectively. On the other hand, average Reference Signal Received Quality (RSRQ) value is decreased by 4% as a tradeoff for the improvements gained.

RF Fingerprints Prediction for Cellular Network Positioning: A Subspace Identification Approach

Cellular network positioning is a mandatory requirement for localizing emergency callers, such as E911 in North America. Although smartphones are normally equipped with GPS modules, there are still a large number of users with cell phones only as basic devices, and GPS could be ineffective in urban canyon environments. To this end, the RF fingerprints based positioning mechanism is incorporated into LTE architecture by 3GPP, where the major challenge is to collect geo-tagged RF fingerprints in vast areas. This paper proposes to utilize the subspace identification approach for large-scale RF fingerprints prediction. We formulate the problem into the problem of finding the optimal subspace over Stiefel manifold, and redesign the Stiefel-manifold optimization method with fast convergence rate. Moreover, we propose a sliding window mechanism for the practical large-scale fingerprints prediction scenario, where recorded fingerprints are unevenly distributed in the vast area. Combining the two proposed mechanisms enables an efficient method of large-scale fingerprints prediction in the city level. Further, we validate our theoretical analysis and proposed mechanisms by conducting experiments with real mobile data, which shows that the resulted localization accuracy and reliability with our predicted fingerprints exceed the requirement of E911.

Skycore

Deploying LTE networks on modern UAVs requires a redesign of the key components of the LTE architecture. In this article, we propose a radical, edge-EPC design, called SkyCore, that pushes one of its central functionalities, namely its evolved packet core (EPC) to the extreme edge of the LTE network - collapses the EPC into a single, lightweight, selfcontained entity that is co-located with each of the UAV base-stations. SkyCore incorporates elements that are designed to address the unique challenges facing such a distributed design in the UAV environment, namely the resource-constrained nature of UAV platforms, and the distributed management of UAV and user mobility. We build and deploy a fully functional SkyCore system on a multi-UAV LTE network and showcase its (i) ability to interoperate with commercial LTE basestations as well as smartphones, (ii) support for both hotspot and standalone multi-UAV deployments, and (iii) robust control and data plane performance compared to other EPC variants in this inherently dynamic, unreliable environment.

Modeling Handover Signaling Messages in OpenFlow-Based Mobile Software-Defined Networks

The software-defined networking (SDN) paradigm has become essential in tackling several issues and challenges in conventional networking, especially in mobile/cellular networks. In order to realize the benefits brought by SDN to mobility management, we study the effects of SDN in conjunction with OpenFlow protocol on the handover procedure. However, in this new setting, the handover still suffers from delay due to the exchange of OpenFlow signaling messages. In this paper, we focus on SDN in mobile networks and quantify the delays of handover-related OpenFlow messages in order to identify the performance measures as well as the underlying challenges. For our analysis, we provide an analytical model, using which we modeled two handover-related OpenFlow messages in such networks. To the best of our knowledge, no previous work has modeled OpenFlow messages other than Packet-in messages. In this paper, in addition to the Packet-in message, we model Port-status messages. Following our analysis, we propose a novel solution to make handover more efficient and less interruptive. Furthermore, we study our solution in an LTE architecture and compare it to an existing solution. We show that, in normal traffic conditions, our solution can decrease the handover delay as much as 20%.

Multicasting in Next-Generation Software-Defined Heterogeneous Wireless Networks

Multicasting is an efficient mechanism to disseminate popular multimedia content to multiple interested third generation partnership project (3GPP) cellular users. To further enhance the multicast cellular capacity, non-3GPP WLAN networks can be leveraged to relieve the load of the 3GPP cellular networks. In this paper, we propose the distributed procedure of de-touring the multicast traffic to WLAN in the current LTE and WLAN heterogeneous network architecture. We also propose promising software-defined networking (SDN)-based centralized approach that facilitates multicast content dissemination, bringing efficiency and flexibility to the network. We analyze both the distributed and centralized approaches based on the multicast content popularity. Our analysis reveals that the SDN-based approach in heterogeneous cellular communication and multicasting brings significant radio resource savings. We also conduct packet-level simulation with a real SDN controller and smartphones to confirm the feasibility of the proposed SDN-based approach.

Survey on Scheduling and Radio Resources Allocation in LTE

This paper focuses on an essential task of the enhanced NodeB eNodeB element in LTE architecture, the Radio Resource Manager RRM, which aims to accept or reject requests for connection to the network based on some constraints and ensuring optimal distribution of radio resources between Users Equipments UEs. Its main functionalities include Admission Control AC and Packet Scheduling PS. This paper will center mainly on the PS part of the RRM task, which performs the radio resource allocation in both uplink and downlink directions. Several approaches and algorithms have been proposed in the literature to address this need ie : allocate resources efficiently, the diversity and multitude of algorithms is related to the factors considered for the optimal management of radio resource, specifically, the traffic type and the QoS Quality of Service requested by the UE. In this article, an art's state of the radio resource allocation strategies and a detailed study of several scheduling algorithms proposed for LTE (uplink and downlink) are made. Therefore, we offer our evaluation and criticism.

A Survey on Security Aspects for LTE and LTE-A Networks

High demands for broadband mobile wireless communications and the emergence of new wireless multimedia applications constitute the motivation to the development of broadband wireless access technologies in recent years. The Long Term Evolution/System Architecture Evolution (LTE/SAE) system has been specified by the Third Generation Partnership Project (3GPP) on the way towards fourth-generation (4G) mobile to ensure 3GPP keeping the dominance of the cellular communication technologies. Through the design and optimization of new radio access techniques and a further evolution of the LTE systems, the 3GPP is developing the future LTE-Advanced (LTE-A) wireless networks as the 4G standard of the 3GPP. Since the 3GPP LTE and LTE-A architecture are designed to support flat Internet Protocol (IP) connectivity and full interworking with heterogeneous wireless access networks, the new unique features bring some new challenges in the design of the security mechanisms. This paper makes a number of contributions to the security aspects of the LTE and LTE-A networks. First, we present an overview of the security functionality of the LTE and LTE-A networks. Second, the security vulnerabilities existing in the architecture and the design of the LTE and LTE-A networks are explored. Third, the existing solutions to these problems are classically reviewed. Finally, we show the potential research issues for the future research works.

Small-Net vs. Relays in a Heterogeneous Low Energy LTE Architecture

The paper analyzes the energy consumption impact of introducing heterogeneous elements to a homogeneous deployment. Two contrasting low energy heterogeneous architectures are investigated: small cells (Small-Nets) and wireless relays. The investigation employs a multi-cell multi-user dynamic LTE simulator and both deployments are investigated for a range of urban traffic loads. The paper shows that compared to a homogeneous baseline deployment of micro-cells, both deployments reduce the total radio network energy consumption significantly (50 to 60%). The Small-Net approach reduces energy consumption by deploying more low power cells with a macro-overlay and achieves increased network capacity by spectrum reuse. The relaying approach reduces energy consumption by deploying fewer macro-cells and increases network capacity through increasing cell-edge performance. A combination of deployment factors were investigated in order to find the lowest energy architecture within the heterogeneous deployments. For a range of targeted traffic loads, it was found that the lowest energy solution depends on the percentage of high mobility traffic. If the percentage of high-mobility users is below 8%, the Small-Net architecture is the lowest energy architecture. Otherwise, the wireless cell-edge relaying concept offers a greater energy reduction. The paper also presents theoretical upper-bounds on energy reduction for a fixed and changing deployment.

Implementation of Decoders for LTE Interface Messages

Long-term evolution is the next-generation network beyond 3G. In order to initiatively imitate and improve network performance, by research and analysis of signaling message which is transmitted in the LTE network architecture, a decoder module is needed. In this paper, the decoding modules for decoding S3, S4, S5/S8, S10 and S11 interfaces, which use GTPv2 protocol to transmit the messages between the various entities such as SGSN -- MME, SGSN - SGW, SGW - PGW, MME -- MME, MME - SGW and MME -- EIR, respectively are explained. Further, in LTE architecture, there is another interface S1MME which uses S1AP protocol between the eNB and MME entities, in similar way interfaces S13 (MME to EIR), S6a (MME to HSS), Gx (PCRF to PCEF), and SGi (between PGW & PDN) which uses diameter protocol, need to be decoded. Hence, to incorporate the decoding of message fields of above said interfaces in the proposed system, the existing Alcatel-Lucent framework LTEPA is enhanced as the project work.

Dynamic Relaying in 3GPP LTE-Advanced Networks

Relaying is one of the proposed technologies for LTE-Advanced networks. In order to enable a flexible and reliable relaying support, the currently adopted architectural structure of LTE networks has to be modified. In this paper, we extend the LTE architecture to enable dynamic relaying, while maintaining backward compatibility with LTE Release 8 user equipments, and without limiting the flexibility and reliability expected from relaying. With dynamic relaying, relays can be associated with base stations on a need basis rather than in a fixed manner which is based only on initial radio planning. Proposals are also given on how to further improve a relay enhanced LTE network by enabling multiple interfaces between the relay nodes and their controlling base stations, which can possibly be based on technologies different from LTE, so that load balancing can be realized. This load balancing can be either between different base stations or even between different networks.