Radio Access Network Technologies Research Articles

Inference of Wi-Fi busy time fraction based on Markov chains

IEEE 802.11 has emerged as a vital wireless network access technology for mobile devices. By providing the potential for high connectivity speeds, this technology has led to a huge rise in the number of access points (APs). In such environments, mobile devices have the choice to join several Wi-Fi networks. Despite its importance to user Quality of Experience (QoE), the AP selection is still trivial since it focuses at best on the received signal strength if not only the user’s history. Crucial metrics that capture the overall dynamics of the AP load condition, such as the network load, are not taken into account. In this paper, we propose to use the Busy Time Fraction (BTF) as a metric to choose the best AP to attach to. The BTF level of a given channel is inferred based on the frame aggregation scheme proposed since the 802.11n standard. In this regard, we build a proof of concept system, FAM (Frame Aggregation based method) that leverages the theoretical frame aggregation levels of a probe traffic returned by two analytical Markovian models and the measured ones in order to estimate not only the BTF but also the nature of the traffic. We validate the accuracy of our proposed approach against ns-3 simulations under several scenarios.

A Green Converged TWDM-PON and 5G HetNet Catering Applications Demanding Low Latency

Abstract Integration of Passive Optical Network (PON) and wireless network technologies can offer a high data rate with ubiquitous Internet access to the end-users. Due to the growing importance of reducing the carbon footprint of telecommunication networks, energy-saving mechanisms are dispensed in the networking equipment. One of the commonly used approaches to reduce energy consumption is the “sleep mode” in which a network equipment periodically turns off some of its components so as to reduce energy consumption. Note that, the current PON and wireless access network technologies have their own power-saving modes. In order to gain power-saving and meet latency of applications in an integrated PON and wireless access network technologies, both optical and wireless access technologies need to have consent on how traffic management (bandwidth allocation, traffic forwarding path), as well as power-saving modes, should be managed in the network. That is, there needs to have synchronization of these two network segments. Otherwise, the end-users would experience longer delay and lower throughput. In this paper, we introduce a Delay-Aware Integrated Sleep Mode (DISM) solution designed considering 5G Heterogeneous Networks (HetNets) architecture which connected with core networks through Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON). In particular, we propose a power saving mechanism using sleep mode for TWDM-PON taking into account packet forwarding delay from the optical network termination point to the end-users’ mobile terminal so as to maximize energy-saving in TWDM-PON while meeting latency requirements of applications with stringent latency requirements. Results obtained through simulations impart that our proposed scheme can significantly satisfy the delay requirement of the traffic while it can still reduce energy consumption in TWDM-PON. Furthermore, the results provide insights on how power saving mechanism in PON should be managed for such 5G HetNet and optical integrated networks in order to satisfy the latency requirement of the traffic.

Physical layer identification of LoRa devices using constellation trace figure

LoRa wireless technology is a revolutionary wireless network access technology with a wide application prospect. An identification method for Lora devices based on physical layer fingerprinting is proposed to provide identities for authentication. Contrary to previous works, a differential constellation trace figure is established from the radio frequency (RF) fingerprinting features of LoRa devices, which transforms the feature matching to the image recognition. A classification method based on Euclidean distance of clustering center of LoRa signal is performed to analyze the differential constellation trace figure. The experimental results show that six LoRa transmission modules can be recognized accurately, and even in a low signal-to-noise ratio (SNR) environment, the different LoRa devices can still be distinguished and identified effectively.

PO-MPTCP: Priorities-Oriented Data Scheduler for Multimedia Multipathing Services

With the diversified wireless network access technology and large-scale equipment of multinetwork interface devices expanding, network transmission performance for multi-homed terminals has been widely concerned by academic circles. More and more scholars have paid attention to Multipath Transmission Control Protocol (MPTCP) as one of the representative methods for studying path transmission performance. However, their studies ignore the impact of dynamic network environments on data transmission performance and seldom consider the priority of data transmission. Undoubtedly, not prioritizing packets will have a dramatic effect on the users experience in the heterogeneous networks. In this paper, we propose a novel priority-aware streaming media multipath data scheduler mechanism (PO-MPTCP) to achieve the following goals: (1) detecting the priority of all streaming media data; (2) achieving multiattribute-aware path evaluation and switching mechanism; (3) introducing a path-quality priority-driven data distribution mechanism to improve streaming multipath transmission performance. The simulation experiment shows that PO-MPTCP proposed by this paper improves the transmission performance of streaming media and reduces the transmission delay. For the result of simulation experiment, it is easy for us to find that PO-MPTCP is more efficient in data delivery than the standard MPTCP mechanism.

Constraint Hubs Deployment for Efficient Machine-Type Communications

Massive Internet of Things (mIoT) is an important use case of 5G. The main challenge for mIoT is the huge amount of uplink traffic as it dramatically overloads the radio access network (RAN). To mitigate this shortcoming, a new RAN technology has been suggested, where small cells are used for interconnecting different devices to the network. The use of small cells will alleviate congestion at the RAN, reduce the end-to-end (E2E) delay, and increase the link capacity for communications. In this paper, we devise three solutions for deploying and interconnecting small cells that would handle mIoT traffic. A realistic physical model is considered in these solutions. The physical model is based on a composite fading channel that captures path loss, fast fading, shadowing, and interference to derive the signal-to-interference-plus-noise ratio. The three solutions consider two conflicting objectives, namely the cost and the E2E delay for deploying and backhauling small cells. The first solution minimizes the cost while the second reduces the E2E delay. The third solution uses bargaining game theory for reducing both the cost and the E2E delay. The proposed solutions are evaluated through simulations. The obtained results demonstrate the efficiency of each solution in achieving its design goals.

Learning Radio Resource Management in RANs: Framework, Opportunities, and Challenges

In the fifth generation (5G) of mobile broadband systems, radio resource management (RRM) will reach unprecedented levels of complexity. To cope with the ever more sophisticated RRM functionalities and the growing variety of scenarios, while carrying out the prompt decisions required in 5G, this manuscript presents a lean RRM architecture that capitalizes on recent advances in the field of machine learning in combination with the large amount of data readily available in the network from measurements and system observations. The architecture consists of a learner (or a few), which learns RRM policies directly from the data gathered in the network using a single general-purpose learning framework, and a set of distributed actors, which execute RRM policies issued by the learner and repeatedly generate samples of experience. Thus, the complexity of RRM is shifted to the design of the learning framework, while the RRM algorithms derived from this framework are executed in a computationally efficient distributed manner at the radio access nodes. The potential of this approach is verified in a pair of pertinent scenarios, and future directions on applications of machine learning to RRM are discussed. Although we focus on a mobile broadband context, the concepts proposed hereafter extend to any radio access network technology where one can conceive the idea of a central learning unit gathering data from distributed actors.

Next Generation New Radio Small Cell Enhancement: Architectural Options, Functionality and Performance Aspects

The 3rd generation partnership project (3GPP) has been engaged in further advancing the evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN) and UTRAN based radio access network technologies. New radio (NR) is the 3rd generation partnership project (3GPP) endeavor for outlining and standardization of the 5th generation (5G) advanced radio access technology. 3GPP has released the first set of 5G NR standards, i.e., the non-standalone 5G radio specifications. As long-term evolution (LTE) technology is massively deployed and broadly accepted, the transition from LTE to 5G is very critical, and it is of maximal importance that the backward compatibility of 5G with LTE is considered. 3GPP has identified several architecture options for 5G. This article gives an overview of the NR architecture options, their deployment scenarios, and the key migration paths. The LTE-NR dual connectivity (DC) is presented. This DC scenario is unique in the sense that DC is being endowed for two different generations of 3GPP radio access technologies. We, further, present the integration of multipath transmission control protocol (MPTCP) with LTE-NR DC and DC-like aggregation, i.e., 3GPP-non-3GPP interworking to bring in the advantages of MPTCP in terms of link robustness, reliability and dynamic mapping between the traffic flows and the available paths. Finally, we discuss the future research and standardization directions of the next-generation networks.

On Optimal Infrastructure Sharing Strategies in Mobile Radio Networks

The rapid evolution of mobile radio network technologies poses severe technical and economical challenges to mobile network operators (MNOs); on the economical side, the continuous roll-out of technology updates is highly expensive, which may lead to the extreme, where offering advanced mobile services becomes no longer affordable for MNOs which thus, are not incentivized to innovate. Mobile infrastructure sharing among MNOs becomes then an important building block to lower the required per-MNO investment cost involved in the technology roll-out and management phases. We focus on a radio access network (RAN) sharing situation where multiple MNOs with a consolidated network infrastructure coexist in a given set of geographical areas; the MNOs have then to decide if it is profitable to upgrade their RAN technology by deploying additional small-cell base stations and whether to share the investment (and the deployed infrastructure) of the new small-cells with other operators. We address such strategic problems by giving a mathematical framework for the RAN infrastructure sharing problem which returns the “best” infrastructure sharing strategies for operators (coalitions and network configuration) when varying techno-economic parameters such as the achievable throughput in different sharing configurations and the pricing models for the service offered to the users. The proposed formulation is then leveraged to analyze the impact of the aforementioned parameters/input in a realistic mobile network environment based on LTE technology.

Trade-Off Between Power and Bandwidth Consumption in a Reconfigurable Xhaul Network Architecture

The increasing number of wireless devices, the high required traffic bandwidth, and power consumption will lead to a revolution of mobile access networks, which is not a simple evolution of traditional ones. Cloud radio access network technologies are seen as promising solution in order to deal with the heavy requirements defined for 5G mobile networks. The introduction of the common public radio interface (CPRI) technology allows for a centralization in BaseBand unit (BBU) of some access functions with advantages in terms of power consumption saving when switching off algorithms are implemented. Unfortunately, the advantages of the CPRI technology are to be paid with an increase in required bandwidth to carry the traffic between the BBU and the radio remote unit (RRU), in which only the radio functions are implemented. For this reason, a tradeoff solution between power and bandwidth consumption is proposed and evaluated. The proposed solution consists of: 1) handling the traffic generated by the users through both RRU and traditional radio base stations (RBS) and 2) carrying the traffic generated by the RRU and RBS (CPRI and Ethernet flows) with a reconfigurable network. The proposed solution is investigated under the lognormal spatial traffic distribution assumption. After proposing resource dimensioning analytical models validated by simulation, we show how the sum of the bandwidth and power consumption may be minimized with the deployment of a given percentage of RRU. For instance we show how in 5G traffic scenarios this percentage can vary from 30% to 50% according to total traffic amount handled by a switching node of the reconfigurable network.

Cost-Reliability Tradeoff in Licensed and Unlicensed Spectra Interoperable Networks with Guaranteed User Data Rate Requirements

Unlicensed spectra access holds the promise of alleviating licensed spectra scarcity and providing super high-rate mobile data services, which has been viewed as one of the key technologies of fifth generation (5G) cellular networks. In this paper, we first design a framework for 5G licensed and unlicensed spectra interoperable networks based on the cloud radio access network technology and the control/data decoupled architecture. Then, we investigate network-level cost-reliability tradeoff from two aspects. First, we study a fundamental tradeoff between the cost and the reliability by minimizing cost for a given reliability level. Second, we define a quality of experience efficiency utility as the complementary measure to characterize the cost and the reliability, offering an inherent tradeoff between them. Moreover, an interference power estimation method is proposed to more accurately estimate channel states to guarantee resource allocation effectiveness. Finally, we conduct extensive simulation study and demonstrate the effectiveness of the interference power estimation method.

Quality of consumer experience data mining for mobile multimedia communication networks: learning from measurements campaign

This paper presents an experimental approach of the major data mining algorithms which can be applied to the quality prediction of provided services by contemporary mobile communication networks. Recent developments in performance evaluation of rollout mobile communication networks are based on drive-test measurement campaigns as well as on network monitoring and management systems. In addition, large measurement databases as well as data warehouses are created, updated and used for a drill-down statistics analysis. An empirical comparison of modern data mining methods for quality prediction and estimation of speech and video telephony services is presented. Learning prediction models are constructed from live network measurements which have been previously collected by experimental equipment during measurement campaigns. Practically and summing up, the proposed engineering approach is general and is applicable to various radio access network technologies during planning and optimisation phases.

Multicast group membership management in media independent handover services

Currently we are witnessing an explosion of devices able to connect to a variety of wired and wireless access network technologies. This connectivity is increasingly integrating networks composed by sensors, actuators and even utility devices that use private and public networks to relay important information and measurements. The deployment of the so-called Smart Grid technologies allied to the rise of Machine-to-Machine communications require new mechanisms to optimally manage the change of point of attachment to the network of these huge clouds of nodes, assisting in tackling the scale of the problem. With this problematic in mind, the IEEE 802.21 WG started on March 2012 a new project, named IEEE 802.21d, group management services. This amendment establishes the required changes to the original specification, in order to manage the mobility of groups of nodes. This work follows closely the progress of the Task Group on the use cases, requirements and gap analysis, providing in addition a potential solution, integrating new group mechanisms, extensions to the MIH Protocol and associated security enhancements. This solution has been implemented and validated in a custom built testbed, with results showing that the utilisation of Group Control procedures through multicast signalling achieves a lower cost when compared with unicast signalling, in group handover and sensor information dissemination scenarios.

A Cross-Layer Qos Based Scheduling Algorithm WRR Design in Wimax Base Stations

The IEEE 802.16 standard defines a wireless broadband access network technology called Wimax. It introduces several advantages, one of which is the support for Quality of Service (QoS) at the MAC level. To ensure meeting the QoS requirements, the 802.16 base stations must run some algorithms to allocate slots between connections. Call admission and scheduling are the strongest tools in our hand to ensure QoS. We propose an efficient design architecture that is capable of allocating slots based on the QoS requirements, bandwidth request sizes, and the 802.16 network parameters. To test the proposed solution, we have implemented a cross layer between the 802.16 MAC and the network layers in the NS-2 simulator and, then in RTL level with VHDL to be designed in FPGA. Several simulation scenarios are presented. According to the simulation results, the proposed scheduling solution ensures the QoS requirements of all 802.16 service classes. The solution shares free resources weighted fairly and demonstrates work-conserving behavior. The proposed design in this paper was analyzed: simulation results show a significant performance improvement in terms of overall throughput and delay when compared to recently published work.

Dynamic target wireless network selection technique using fuzzy linguistic variables

Even though various wireless Network Access Technologies (NATs) with different specifications and applications have been developed in the recent years, no single wireless technology alone can satisfy the anytime, anywhere, and any service wireless-access needs of mobile users. A real seamless wireless mobile environment is only realized by considering vertical and horizontal handoffs together. One of the major design issues in heterogeneous wireless networks is the support of Vertical Handoff (VHO). VHO occurs when a multi-interface enabled mobile terminal changes its Point of Attachment (PoA) from one type of wireless access technology to another, while maintaining an active session. In this paper we present a novel multi-criteria VHO algorithm, which chooses the target NAT based on several factors such as user preferences, system parameters, and traffic-types with varying Quality of Service (QoS) requirements. Two modules i.e., VHO Necessity Estimation (VHONE) module and target NAT selection module, are designed. Both modules utilize several “weighted” users' and system's parameters. To improve the robustness of the proposed algorithm, the weighting system is designed based on the concept of fuzzy linguistic variables.

Game Theory-Based Network Selection: Solutions and Challenges

In order to cater for the overwhelming growth in bandwidth demand from mobile Internet users operators have started to deploy different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to enable network selection mechanisms in order to keep the mobile users Always Best Connected (ABC) anywhere and anytime. Game theory techniques have been receiving growing attention in recent years as they can be adopted in order to model and understand competitive and cooperative scenarios between rational decision makers. This paper presents an overview of the network selection decision problem and challenges, a comprehensive classification of related game theoretic approaches and a discussion on the application of game theory to the network selection problem faced by the next generation of 4G wireless networks.

TRIM: An architecture for transparent IMS-based mobility

In recent years, the development and deployment of new wired and wireless access network technologies have made the ubiquitous Internet a reality. Users can access anywhere and anytime to the broad set of value-added Internet services, which are delivered by means of the IP protocol. In this context, 3GPP is currently developing the IP Multimedia Subsystem (IMS), as a key element that allows to evolve from the ubiquitous access to the Internet services towards a next generation network model, by providing a set of essential facilities such as session control, QoS, charging and service integration. Nevertheless, several open issues still need consideration before the future Internet becomes real, such as supporting user mobility in IP networks. Although mobility support in the Internet is receiving much attention, IMS networks present inherent particularities that require further analysis. The solutions proposed so far for IMS do not support mobility transparently to the end-user applications, or address the problem by introducing complex changes to the IMS infrastructure. This paper presents TRIM, an architecture for transparent IMS-based mobility. TRIM supports mobility in IMS networks transparently to the end-user applications, which are unaware of the handover management procedures executed between the mobile node and the network. We have performed several experiments with a TRIM prototype, using a real IMS testbed with 3G and WLAN access networks, validating the proposal for UDP and TCP based applications.

Scheduling solution for the IEEE 802.16 base station

The IEEE 802.16 standard defines a wireless broadband access network technology called WiMAX. It introduces several advantages, one of which is the support for QoS at the MAC level. To ensure meeting the QoS requirements, the 802.16 base station must run some algorithm to allocate slots between connections. This algorithm is not defined in the 802.16 specification but rather is open for alternative implementations. We propose a simple, yet efficient, solution that is capable of allocating slots based on the QoS requirements, bandwidth request sizes, and the 802.16 network parameters. To test the proposed solution, we have implemented the 802.16 MAC and PHY layers in the NS-2 simulator. Several simulation scenarios are presented that demonstrate how the scheduling solution allocates resources in various cases. According to the simulation results, the proposed scheduling solution ensures the QoS requirements of all 802.16 service classes. The solution shares free resources fairly and demonstrates work-conserving behaviour.

A CUSTOMIZABLE QOS STRATEGY FOR CONVERGENT HETEROGENEOUS WIRELESS COMMUNICATIONS

This article proposes a general customizable QoS scenario for heterogeneous wireless access network technologies. The scenario provides robust and flexible QoS support by adapting the amount of resources reserved for the characteristics of the wireless channel, as well as automatic reconfiguration mechanisms of the multimedia encoding rate and error-resilient techniques to adapt to the dynamic mobile communication environment. Two new scenarios, adaptive FEC and MAC-Lite, are introduced to the proposed scheme. These enable a maximizing of the overall performance of the wireless network. The appropriate interfaces within the core network are described for performing end-to-end QoS, which deliver network meters and exchange QoS parameters with the proposed intra and inter cross-layer approaches, including context transfer during handover. Each part, extended by the proposed method can be configured by the application and be independently implemented. To evaluate the proposed scheme, the QoS components were integrated into a trial platform that was built and simulations were then performed. The results demonstrate that the communication quality was significantly improved

IMS Signaling over Current Wireless Networks: Experiments Using the Open IMS Core

The IP Multimedia Subsystem (IMS) as defined by the 3GPP emerges as blueprint for a central architecture to provide Next Generation Network (NGN) services. As overlay architecture for IP based access networks, it provides standardized interfaces to services which will merge the advantages of traditional telephony networks with the benefits of Internet services. This paper will evaluate how good the current wireless access network technologies are for usage in combination with IMS services. Based upon a reference implementation of IMS core elements, the Open IMS Core, measurements were carried out on signaling to give an indication as to what networks will be most applicable for usage, particularly for a vehicular environment.

A framework of handoffs in wireless overlay networks based on mobile IPv6

Although there are various wireless access network technologies with different characteristics and performance level have been developed, no single network that can satisfy the anytime, anywhere, and any service wireless access needs of mobile users. A truly seamless mobile environment can only be realized by considering vertical and horizontal handoffs together. With the advantages of Mobile IPv6, a more comprehensive and integrated framework of heterogeneous networks can be developed. In this paper, we discuss the issues related to handoffs including horizontal and vertical handoffs. We present a scheme for integrating wireless local area network and wide area access networks, and propose a micromobility management method called HiMIPv6+. We also propose a QoS-based (quality-of-service-based) vertical handoff scheme and algorithm that consider wireless network transport capacity and user service requirement. Our prototype evaluations and the simulations show that our framework performs as expected.