Next-generation Mobile Systems Research Articles

Beyond 5G Fronthaul Based on FSO Using Spread Spectrum Codes and Graphene Modulators.

High data rate coverage, security, and energy efficiency will play a key role in the continued performance scaling of next-generation mobile systems. Dense, small mobile cells based on a novel network architecture are part of the answer. Motivated by the recent mounting interest in free-space optical (FSO) technologies, this paper addresses a novel mobile fronthaul network architecture based on FSO, spread spectrum codes, and graphene modulators for the creation of dense small cells. The network uses an energy-efficient graphene modulator to send data bits to be coded with spread codes for achieving higher security before their transmission to remote units via high-speed FSO transmitters. Analytical results show the new fronthaul mobile network can accommodate up to 32 remote antennas under error-free transmissions with forward error correction. Furthermore, the modulator is optimized to provide maximum efficiency in terms of energy consumption per bit. The optimization procedure is carried out by optimizing both the amount of graphene used on the ring resonator and the modulator's design. The optimized graphene modulator is used in the new fronthaul network and requires as low as 4.6 fJ/bit while enabling high-speed performance up to 42.6 GHz and remarkably using one-quarter of graphene only.

SDVEC: Software-Defined Vehicular Edge Computing with Ultra-Low Latency

New paradigm shifts and 6G technological rev-olution in vehicular services have emerged toward unmanned driving, automated transportation, and self-driving vehicles. As the technology for autonomous cars becomes mature, real challeng-es come from reliable, safe, real-time connected transportation operations to achieve ubiquitous and prompt information exchanges with massive connected and autonomous vehicles. This article introduces novel wireless distributed architectures that embed the edge computing capability inside software-defined vehicular networking infrastructure. Such edge networks consist of open-loop grant-free communications and computing-based control frameworks, which enable dynamic eco-routing with ultra-low latency and mobile data-driven orchestration. Thus, this work advanc-es the frontiers of machine learning potential and next-generation mobile systems in vehicular net-working applications.

Non-Linear Base-Station Processing Within a 3GPP Compliant Framework

MIMO mobile systems, with a large number of antennas at the base-station side, enable the concurrent transmission of multiple, spatially separated information streams, and therefore, enable improved network throughput and connectivity both in uplink and downlink transmissions. Traditionally, such MIMO transmissions adopt linear base-station processing, that translates the MIMO channel into several single-antenna channels. While such approaches are relatively easy to implement, they can leave on the table a significant amount of unexploited MIMO capacity and connectivity capabilities. Recently-proposed non-linear base-station processing methods claim this unexplored capacity and promise substantially increased network throughput and connectivity capabilities. Still, to the best of the authors’ knowledge, non-linear base-station processing methods not only have not yet been adopted by actual systems, but have not even been evaluated in a standard-compliant framework, involving all the necessary algorithmic modules required by a practical system. In this work, for the first time, we incorporate and evaluate non-linear base-station processing in a 3GPP standard environment. We outline the required research platform modifications and we verify that significant throughput gains can be achieved, both in indoor and outdoor settings, even when the number of base-station antennas is much larger than the number of transmitted information streams. Then, we identify missing algorithmic components that need to be developed to make non-linear base-station practical, and discuss future research directions towards potentially transformative next-generation mobile systems and base-stations (i.e., 6G) that explore currently unexploited non-linear processing gains.

Radio-frequency chain selection for energy and spectral efficiency maximization in hybrid beamforming under hardware imperfections

The next-generation wireless communications require reduced energy consumption, increased data rates and better signal coverage. The millimetre-wave frequency spectrum above 30 GHz can help fulfil the performance requirements of the next-generation mobile broadband systems. Multiple-input multiple-output technology can provide performance gains to help mitigate the increased path loss experienced at millimetre-wave frequencies compared with microwave bands. Emerging hybrid beamforming architectures can reduce the energy consumption and hardware complexity with the use of fewer radio-frequency (RF) chains. Energy efficiency is identified as a key fifth-generation metric and will have a major impact on the hybrid beamforming system design. In terms of transceiver power consumption, deactivating parts of the beamformer structure to reduce power typically leads to significant loss of spectral efficiency. Our aim is to achieve the highest energy efficiency for the millimetre-wave communications system while mitigating the resulting loss in spectral efficiency. To achieve this, we propose an optimal selection framework which activates specific RF chains that amplify the digitally beamformed signals with the analogue beamforming network. Practical precoding is considered by including the effects of user interference, noise and hardware impairments in the system modelling.

Energy‐efficient BBU pool virtualisation for C‐RAN with quality of service guarantees

Cloud radio access network (C-RAN) has been introduced as a promising network paradigm for improving the spectral and energy efficiency of next-generation mobile systems. In C-RAN, the computation resources of the centralised baseband units (BBUs) can be virtualised and dynamically shared among cells for energy-efficient BBU pool utilisation. In this study, a BBU virtualisation scheme is proposed to minimise the total power consumption in the BBU pool subject to constraints on users’ quality of service in terms of real-time requirements, individual fronthaul capacity and BBU capacity. As the BBU processing time and transmission delay for each user data can be compromised to meet the user's real-time requirements while minimising the BBU power consumption, a priori user association phase is proposed and formulated as an optimisation problem to maximise the users’ transmission rate, and hence minimising their transmission delay. Then, the BBU processing allocation phase is formulated as a bin-packing problem to minimise the overall power consumption in the BBU pool. Since this problem is combinatorial, a heuristic algorithm is proposed based on best-fit-decreasing algorithm to solve it. Extensive simulations show that the proposed scheme outperforms the comparable ones in terms of power consumption with reduction up to 33%.

Aerial Control System for Spectrum Efficiency in UAV-to-Cellular Communications

The next generation of mobile systems, 5G, will be the communication standard that accommodates the proliferation of the Internet of Things (IoT). Unmanned aerial vehicles (UAVs) are envisioned to support many applications in providing 5G connectivity to the IoT, by extending highspeed connectivity from the sky to objects on the ground, or even by carrying onboard some IoT devices. However, given their critical nature, the management of UAVs induces high exchange of control messages with the ground control station, resulting in the crowded spectrum used by cellular networks. The authors raise the problem of degrading the network spectrum with UAVs' management messages, and discuss the need for an efficient orchestration system. In this article, they propose a novel scheme, dubbed the aerial control system, which is based on separating the data plane from the control plane of UAVs, and pushing the latter to be performed in the air by UAVs. The solution provides an orchestration logic that takes advantage of the autonomous nature of UAVs to organize UAVs in one or several clusters. UAV-to-UAV communication enables spectrum reuse and avoids crowding the network with management messages, while dedicating more 5G spectrum for ensuring more bandwidth to the IoT through UAV-to-infrastructure communication.

An Iterative Power Allocation Algorithm Aimed at Maximization of System Capacity in Two-Tier Cellular Network

To fulfill the urgent requirement for ubiquitous information exchange, the infrastructure of the next-generation mobile system is developing toward a densely distributed cellular network with multiple tiers of base stations and access technologies serving users with different mobility styles and bandwidth demands. Therefore, the need for an advanced power control and interference mitigation strategy is even more prominent. This paper proposes an iterative power allocation algorithm for mobile users within a two-tier mobile network infrastructure. The algorithm is based on Newton’s method and is aimed at maximizing system capacity of the whole system. Simulation results prove that, compared to the traditional power control scheme, the proposed scheme remarkably improves utilization of latent system capacity and effectively reduces user power consumptions, and the algorithm possesses a favorable performance of convergence

Survey of Promising Technologies for 5G Networks

As an enhancement of cellular networks, the future-generation 5G network can be considered an ultra-high-speed technology. The proposed 5G network might include all types of advanced dominant technologies to provide remarkable services. Consequently, new architectures and service management schemes for different applications of the emerging technologies need to be recommended to solve issues related to data traffic capacity, high data rate, and reliability for ensuring QoS. Cloud computing, Internet of things (IoT), and software-defined networking (SDN) have become some of the core technologies for the 5G network. Cloud-based services provide flexible and efficient solutions for information and communications technology by reducing the cost of investing in and managing information technology infrastructure. In terms of functionality, SDN is a promising architecture that decouples control planes and data planes to support programmability, adaptability, and flexibility in ever-changing network architectures. However, IoT combines cloud computing and SDN to achieve greater productivity for evolving technologies in 5G by facilitating interaction between the physical and human world. The major objective of this study provides a lawless vision on comprehensive works related to enabling technologies for the next generation of mobile systems and networks, mainly focusing on 5G mobile communications.

Lithographically Defined Three-dimensional Pore-patterned Carbon with Nitrogen Doping for High-Performance Ultrathin Supercapacitor Applications

Supercapacitors that exhibit long cycle lives and fast charge/discharge rates are a promising energy-storage technology for next-generation mobile or wearable electronic systems. A great challenge facing the fabrication of ultrathin supercapacitor components, specifically their porous electrodes, is whether such components can be integrated with the fabrication of electronic devices, i.e., semiconductor fabrication processes. Here, we introduce the lithographic fabrication of micrometre-thick, submicrometre-pore-patterned carbon for supercapacitor electrodes. The pore patterns designed by multi-beam interference lithography and direct carbonisation of the photoresist pattern produced pore-patterned carbon films. A facile doping process was subsequently employed to introduce nitrogen atoms into the carbon, which was intended to further enhance the carbon's capacitive properties. Specifically, during these fabrication steps, we developed an approach that uses a supporting shell on the surface of the pore patterns to maintain their structural integrity. The nitrogen-doped, pore-patterned carbon electrodes exhibited an areal specific capacitance of 32.7 mF/cm2 at 0.5 mA/cm2 when used as supercapacitor electrodes, which is approximately 20 times greater than that of commercially available MWCNT films measured under the same conditions.

A Spectrum Sharing Model for Compatibility between IMT-Advanced and Digital Broadcasting

Recently, the International Telecommunication Union allocated the 470?862 MHz band to the digital broadcasting (DB) service. Moreover, the 790?862 MHz sub-band will be allocated to the next-generation mobile system, known as the International Mobile Telecommunication ? Advanced (IMT-A), and to the DB on a co-primary basis in the year 2015. Currently, two candidate technologies are available to represent the IMT-A system; the Mobile WiMAX and Long Term Evolution ? Advanced (LTE-A). One of the main criteria of the IMT-A candidate is to not cause additional interference to the primary service (i.e., DB). In this paper, we address the spectrum sharing issue between the IMT-A candidates and the DB service. More precisely, we investigate the interference effect between the DB service and the mobile network, which could be either LTE-A or WiMAX. Our study proposes a spectrum sharing model to take into account the impact of interference and evaluates the spectrum sharing requirements such as frequency separation and separation distance. This model considers three spectrum sharing scenarios: co-channel, zero guard band, and adjacent channel. A statistical analysis is performed, by considering the interferer spectrum emission mask and victim receiver blocking techniques. The interference-to-noise ratio is used as an essential spectrum sharing criterion between the systems. The model considers the random distribution of the users, antenna heights, and the bandwidth effect as well as the deployment environment in order to achieve spectrum sharing. The results show that LTE-A is preferable to WiMAX in terms of having less interference impact on DB; this can eventually allow the operation of both services without performance degradation and thus will lead to efficient utilization of the radio spectrum.

Multicore DSP programming models [In the Spotlight

A recent article in "Information Week" online [1] discussed the positive prospects for wide deployment of the next generation of mobile communication systems. These systems, embodied first in the form of WiMAX technology and later in the form of LTE (Long Term Evolution) technology promise a notable increase in communication speed and quality. With the increase in performance comes also an increase in the processing needs for the devices enabling these technologies. At the base station side, the deployment of the next generation of mobile systems is in many ways possible in a cost effective form thanks to the use of multicore DSPs.

Proposal and analysis of adaptive mobility management in ip-based mobile networks

Efficient mobility management is one of the major challenges for next-generation mobile systems. Indeed, a mobile node (MN) within an access network may cause excessive signaling traffic and service disruption due to frequent handoffs. The two latter effects need to be minimized to support quality of service (QoS) requirements of emerging multimedia applications. In this paper, we propose a new adaptive micromobility management scheme designed to track efficiently the mobility of nodes so as to minimize both handoff latency and total signaling cost while ensuring the MN's QoS requirements. We introduce the concept of residing area. Accordingly, the micromobility domain is divided into virtual residing areas where the MN limits its signaling exchanges within this local region instead of communicating with the relatively far away root of the domain at each handoff occurrence. A key distinguishing feature of our solution is its adaptive nature since the virtual residing areas are constructed according to the current network state and the QoS constraints. To evaluate the efficiency of our proposal, we compare our scheme with existing solutions using both analytical and simulation approaches for the 2-D random walk model as well as real mobility patterns. Numerical and simulation results show that our proposed scheme can significantly reduce registration updates and link usage costs and provide low handoff latency and packet loss rate under various scenarios.

Seamless integration of mobile WiMAX in 3GPP networks

As the wireless industry makes its way to the next generation of mobile systems, it is important to engineer solutions that enable seamless integration of emerging 4G access technologies within the currently deployed and/or evolved 2G/3G infrastructures. In this article we address a specific case of such a seamless integration, that of mobile WiMAX in evolved 3GPP networks. In this context we investigate the architecture and the key procedures that enable this integration, and we also introduce a novel handover mechanism that enables seamless mobility between mobile WiMAX and legacy 3GPP access, such as UTRAN or GERAN. The core characteristic of this novel handover mechanism is that mobile terminals do not need to support simultaneous transmission on both WiMAX and 3GPP accesses; therefore, it mitigates the RF coexistence issues that exist otherwise and improves handover performance. In addition, we provide a brief overview of mobile WiMAX and the evolved 3GPP network technologies, and we set the appropriate background material before presenting our proposed handover mechanism. Our main conclusion is that integrating mobile WiMAX in evolved 3GPP networks is a compelling approach for providing wireless broadband services, and mobility across WiMAX and 3GPP access can become seamless and efficient with no need for mobile terminals to support simultaneous transmission on both types of access.

A Comprehensive Analysis of Mobility Management in MPLS-Based Wireless Access Networks

Efficient mobility management is one of the major challenges for next-generation mobile systems. Indeed, a mobile node (MN) within an access network may cause excessive signaling traffic and service disruption due to frequent handoffs. The two latter effects need to be minimized to support quality-of-service (QoS) requirements of emerging multimedia applications. In this perspective, we propose in this paper a new mobility management scheme designed to track host mobility efficiently so as to minimize both handoff latency and signaling cost. Building on and enhancing mobile IP and taking advantage of MPLS traffic engineering capability, three mechanisms (FH-, FC- and MFC-micro mobile MPLS) are introduced. In order to assess the efficiency of our proposals, all protocols are compared. To achieve this, we develop analytical models to evaluate the signaling cost and link usage for both two-dimensional and one-dimensional mobility models. Additional mathematical models are also provided to derive handoff latency and packet loss rate. Numerical and simulation results show that the proposed mechanisms can significantly reduce the registration updates cost and provide low handoff latency and packet loss rate under various scenarios.

Modelling of radiofrequency MEMS bulk acoustic wave resonators with Legendre polynomial method

Radio‐Frequency electro‐acoustic resonators and filters are key components for wireless communication devices. The next generation of mobile systems requires for these components a strict size reduction, higher operating frequency and better power resistance. So, MEMS BAW (Bulk Acoustic Wave) devices have emerged as an efficient alternative to established Surface Acoustic Wave filtering solutions. Knowledge of the electromechanical coupling coefficient and the Q‐factor are of primary importance for the MEMS BAW device design. In our model, the Legendre polynomial method which describes the structure and incorporates automatically the boundary conditions in constitutive and propagation equations is used to calculate these parameters. It is the first time this method is applied to study standing rather than propagative waves. The advantage of this approach are, in a unique formulation, to take into account the presence of sources, existence of electrodes' losses and dissimilarity of the constituent materials of the resonator. To validate this approach, it is applied to a Al/ZnO/Al resonator. Through harmonic and modal analysis, the influence of electrodes properties on MEMS BAW resonator performances are illustrated; the results are compared with those published earlier. This method is an efficient tool for designing MEMS BAW filter.

An open baseband processing architecture for future mobile terminal design

This article introduces an open wireless architecture (OWA) mobile terminal design, focusing on the open baseband processing platform, to support different existing and future wireless communication standards through multi-dimensional open baseband processing modules with open interface parameters and baseband management systems. The article describes a multilayer, open architecture platform to maximize system flexibility and minimize terminal power consumption, so as to provide an integrated and converged next-generation wireless and mobile communication terminal system. The OWA platform is fully compatible with the computer architecture, with interface-based rather than transmission-specific system architecture, for complete openness and simplicity.

Strategic design issues of IMS versus end‐to‐end architectures

Purpose - The paper aims to discuss the business issues surrounding the choice between the end-to-end internet architecture, in particular peer-to-peer networks, versus managed telecommunications architectures, in particular IMS, for the migration towards a next-generation mobile system. Design/methodology/approach - The paper organises the arguments available in the literature and technical field along four critical business design dimensions, providing a balanced overview of both sides of the argument. Findings - The paper discriminates between weak and strong arguments on both sides, and introduces a number of recommendations towards actors that will implement IMS. Research limitations/implications - The arguments collected from the literature and industry are not exhaustive but selected on their relevancy for business repercussions. Originality/value - While most position papers on IMS or P2P are written from an opinionated perspective, this paper offers a trade-off view of both side's advantages and disadvantages. It reframes the dispute as a number of design trade-offs to be made on various levels.

Model-based service discovery for next-generation mobile systems

The practical success of next-generation mobile systems such as 4G relics largely on its flexibility in providing adaptive and cost-effective services. Service discovery is an essential mechanism to achieve this goal. Based on the investigation of the existing service discovery protocols, this article proposes a new service discovery methodology for next-generation mobile systems: model-based service discovery or MBSD. By taking advantage of the object management group (OMG) model-driven architecture (MDA) technique, model-based service discovery (MBSD) can generate service description automatically and more precisely. Furthermore, if developed via MDA, the discovered services can be regenerated into their model format and as such facilitate the service re-engineering in a finer manner. The system architecture of MBSD and its operation are presented and implemented. The proposed methodology is validated via a mobile service scenario

Context-aware semantic discovery for next generation mobile systems

A mass market of users with differentiated preferences and heterogeneous wireless terminals will increasingly access services dynamically introduced by competitor providers. In next-generation mobile systems, novel solutions for user-centric service discovery are crucial to provide personalized views of only the services of potential interest. The service view personalization should be based on user context, for example, user preferences, access device capabilities, and environment conditions, and should exploit semantic technologies to allow flexible matching between requirements and capabilities in open and dynamic deployment scenarios. Our MIDAS middleware exemplifies how to exploit context awareness based on user/device/service profile metadata and semantic-based matchmaking

Advances in service platform technologies for next-generation mobile systems: part 2

Advances in service platform technologies for next-generation mobile systems: part 2