Ethernet Fronthaul and Time-Sensitive Networking for 5G and Beyond Mobile Networks

Ethernet has been proposed to be used as the transport technology in the future fronthaul network. For this purpose, a model of switched Ethernet architecture is developed and presented in order to characterise the performance of an Ethernet mobile fronthaul network. The effects of traditional queuing regimes, including Strict Priority (SP) and Weighted Round Robin (WRR), on the delay and delay variation of LTE streams under the presence of background Ethernet traffic are investigated using frame inter-arrival delay statistics. The results show the effect of different background traffic rates and frame sizes on the mean and Standard Deviation (STD) of the LTE traffic frame inter-arrival delay and the importance of selecting the most suitable queuing regime based on the priority level and time sensitivity of the different traffic types. While SP can be used with traffic types that require low delay and Frame Delay variation (FDV), this queuing regime does not guarantee that the time sensitive traffic will not encounter an increase in delay and FDV as a result of contention due to the lack of pre-emptive mechanisms. Thus, the need for a queuing regime that can overcome the limitations of traditional queuing regimes is shown. To this extent, Time Sensitive Networking (TSN) for an Ethernet fronthaul network is modelled. Different modelling approaches for a Time Aware Shaper (TAS) based on the IEEE 802.1Qbv standard in Opnet/Riverbed are presented. The TAS model is assumed to be the scheduling entity in an Ethernet-based fronthaul network model, located in both the Ethernet switches and traffic sources. The TAS with/without queuing at the end stations has been presented as well. The performance of the TAS is compared to that of SP and WRR and is quantified through the FDV of the high priority traffic when this contends with lower priority traffic. The results show that with the TAS, contentioninduced FDV can be minimized or even completely removed. Furthermore, variations in the processing times of networking equipment, due to the envisaged softwarization of the next generation mobile network, which can lead to time variation in the generation instances of traffic in the Ethernet fronthaul network (both in the end-nodes and in switches/aggregators), have been considered in the TAS design. The need for a Global Scheduler (GS) and Software Defined Networking (SDN) with TAS is also discussed. An Upper Physical layer functional Split (UPS), specifically a pre-resource mapper split, for an evolved Ethernet fronthaul network is modelled. Using this model and by incorporating additional traffic sources, an investigation of the frame delay and FDV limitations in this evolved fronthaul is carried out. The results show that contention in Ethernet switch output ports causes an increase in the delay and FDV beyond proposed specifications for the UPS and other time sensitive traffic, such as legacy Common Public Radio Interface (CPRI)-type traffic. While TAS can significantly reduce or even remove FDV for UPS traffic and CPRI-type traffic, it is shown that TAS design aspects have to carefully consider the different transmission characteristics, especially the transmission pattern, of the contending traffic flows. For this reason, different traffic allocations within TAS window sections are proposed. Furthermore, it is demonstrated that increased link rates will be important in enabling longer fronthaul fibre spans (more than ten Kilometres fibre spans with ten Gigabit Ethernet links). The results also show that using multiple hops (Ethernet switches/aggregators) in the network can result in a reduction in the amount of UPS traffic that can be received within the delay and FDV specifications. As a result, careful considerations of the fibre span length and the number of hops in the fronthaul network should be made

The effect of different queuing regimes on a Switched Ethernet fronthaul

This paper investigates the effects of different queuing regimes on the mean and standard deviation of the frame inter-arrival delay of a LTE traffic stream under the presence of background Ethernet traffic. The background traffic is used to represent traffic that would be generated by different functional subdivisions in the physical layer of traditional LTE base station. In this work, a Switched Ethernet architecture is used as the fronthaul section of a Cloud Radio Access Network (C-RAN). Contention in this fronthaul becomes an important issue since different traffic streams originating from different functional subdivisions with different quality of service specifications will be transmitted over the same physical links. Trunk ports then, will have to handle the queuing management and prioritization. Handling the traffic with different queuing regimes will reflect on the latency and latency variations of the LTE traffic

The Effect Of Other Information On Equity Valuation: Kuwait Evidence

Previous studies on the value relevance of accounting information adopt Ohlsons linear information dynamics which, if other information is ignored, leads to a theoretical valuation model solely involving earnings, book value, and net shareholder cash flows or (net dividends). The lack of analysis of other value-relevant data may defeat the effectiveness of the Ohlsons model since the current accounting data cannot fully account for future earnings. The potential implication of ignoring other information is that it could introduce bias into estimated coefficients (e.g. Ohlson, 1995; Hand and Landsman, 2005). This study examines the effect of introducing other information proxied by lagged valuation error on equity valuation, utilizing a sample of non-financial companies listed at the Kuwait Stock Exchange (KSE) over the period 2003 to 2009. Empirical results of this study reveal that our proxy for other information appears to capture valuation implications of information other than current variables in the linear information dynamic setting. Results also reveal that adding other information to the valuation model clearly reduces the coefficients on earnings and dividends, and increases the coefficient of book value; however, book value and earnings remain significantly associated with stock prices. As a consequence, current accounting variables appear to be capturing some, but not all, of other information when this variable is omitted. We conclude that other information is an important factor in determining the market value of firms and hence should not be omitted in studies examining the value relevance of accounting information

Financial Performance And Compliance With Basel III Capital Standards: Conventional vs. Islamic Banks

This study is a commentary on the financialperformance and quality capital of Islamic versus conventional banks currentlyoperating in the Gulf Cooperation Council (GCC) region. In addition toassessing the financial performance of the full set of banks across various GCCcountries, the study is the first to consider the extent to which Islamic vs.conventional GCC banks comply with the new Basel III requirements of raising betterquality capital. The study uses bank-level data for 75 (55 conventionaland 20 Islamic) banks in Kuwait, United Arab Emirates, Kingdom of Saudi Arabia,Oman, Qatar, and Bahrain. Financial ratios are used tomeasure and compare Islamic vs. conventional banks’ performances, and weemploy a comprehensive and the most recent sample of data available in the region, consisting of cross-sections from 2003 to 2011. The results reveal that Islamic banks are, onaverage, less efficient but more profitable, more liquid, more solvent (lessrisky), and enjoyed higher internal growth rates than conventional banks during2003-2011. The results indicate that there are statistically significant differencesbetween the two types of banks, as far as profitability, solvency, and internalgrowth rate ratios are concerned; however, there are no statisticallysignificant differences in liquidity and efficiency. The results also indicatethat banks, as a whole, appear to be largely sufficiently capitalized for BaselIII. Gulf Cooperation Council banks are well positioned to absorb higherprovisions and impairment charges given the higher capital adequacy ratiosreported by most. The Common Equity Ratio, Tier 1 Capital Ratio, and Capital AdequacyRatios (CARs), for the majority of banks in 2011, comfortably satisfy theenhanced capital requirements of Basel III. The results show that Islamic bankshave, on average, noticeably higher (and significantly different) capitalratios compared to conventional institutions. With regard to theimpact of the global financial crisis on both types of the banks, the resultsindicate that Islamic banks performed better thanconventional banks during the period 2006-2009, as the former enjoys highercapitalization, higher liquidity reserves, and also maintained stronger growthcompared to conventional banks in almost countries. Findings of this study may be useful for capital-market participants, as the full set of banks across various Gulf Cooperation Councilcountries needs to be examined before any substantive conclusions can bereached about the relative performance of Islamic versus conventional banks.Further, as the full implementation of Basel III requirements will not takeplace until 2019, the results of this study will convey information that shouldencourage banks to consider the earlier implementation of Basel III capitalrequirements in order to provide themselves with a reputational boost, as wellas a competitive advantage

The new flexible mobile fronthaul: Digital or analog, or both?

It has become apparent that current fronthaul technology cannot be simply extended to meet the projected demands of 5G and beyond mobile systems. This current technology, based on the transport of sampled radio waveforms, has been the preferred option, with analog radio over fiber reserved to relatively niche application scenarios. However, for future systems, it is recognised that different functional splits between the central location and the remote units are needed; sampled waveform transport is not scalable to these systems. We propose a flexible fronthaul, therefore, in which both digital and analog transport technologies can coexist. Using practical examples from our work, we describe where these technologies can be used in the future fronthaul

Statistical distribution of packet inter-arrival rates in an Ethernet fronthaul

This paper investigates the effects of background traffic streams in the packet inter-arrival rates of an LTE traffic stream, when these streams are transported over the same Ethernet fronthaul network. Contention of background traffic with LTE traffic can occur in a Cloud-RAN that is transporting traffic streams originating from Constant Bit-Rate (CBR) sources such as the Common Public Radio Interface (CPRI) and from other non-CBR sources originating from different LTE physical layer functional subdivisions. Packet inter-arrival statistics are important in such a network, as they can be used to estimate and/or predict buffer sizes in receiving network nodes. Buffer management will also be important for traffic streams originating from functional splits (such as direct LTE MAC transport block transportation) where user plane data and control primitives have to be time aligned at the receiving node

Systematic Review of Intelligent Algorithms in Gait Analysis and Prediction for Lower Limb Robotic Systems

The rate of development of robotic technologies has been meteoric, as a result of compounded advancements in hardware and software. Amongst these robotic technologies are active exoskeletons and orthoses, used in the assistive and rehabilitative fields. Artificial intelligence techniques are increasingly being utilised in gait analysis and prediction. This review paper systematically explores the current use of intelligent algorithms in gait analysis for robotic control, specifically the control of active lower limb exoskeletons and orthoses. Two databases, IEEE and Scopus, were screened for papers published between 1989 to May 2020. 41 papers met the eligibility criteria and were included in this review. 66.7% of the identified studies used classification models for the classification of gait phases and locomotion modes. Meanwhile, 33.3% implemented regression models for the estimation/prediction of kinematic parameters such as joint angles and trajectories, and kinetic parameters such as moments and torques. Deep learning algorithms have been deployed in ∼15% of the machine learning implementations. Other methodological parameters were reviewed, such as the sensor selection and the sample sizes used for training the models

Wearable Lower-Limb Exoskeleton for Children With Cerebral Palsy: A Systematic Review of Mechanical Design, Actuation Type, Control Strategy, and Clinical Evaluation

Children with a neurological disorder such as cerebral palsy (CP) severely suffer from a reduced quality of life because of decreasing independence and mobility. Although there is no cure yet, a lower-limb exoskeleton (LLE) has considerable potential to help these children experience better mobility during overground walking. The research in wearable exoskeletons for children with CP is still at an early stage. This paper shows that the number of published papers on LLEs assisting children with CP has significantly increased in recent years; however, no research has been carried out to review these studies systematically. To fill up this research gap, a systematic review from a technical and clinical perspective has been conducted, based on the PRISMA guidelines, under three extended topics associated with “lower limb”, “exoskeleton”, and “cerebral palsy” in the databases Scopus and Web of Science. After applying several exclusion criteria, seventeen articles focused on fifteen LLEs were included for careful consideration. These studies address some consistent positive evidence on the efficacy of LLEs in improving gait patterns in children with CP. Statistical findings show that knee exoskeletons, brushless DC motors, the hierarchy control architecture, and CP children with spastic diplegia are, respectively, the most common mechanical design, actuator type, control strategy, and clinical characteristics for these LLEs. Clinical studies suggest ankle-foot orthosis as the primary medical solution for most CP gait patterns; nevertheless, only one motorized ankle exoskeleton has been developed. This paper shows that more research and contribution are needed to deal with open challenges in these LLEs

Switched Ethernet Fronthaul Architecture for Cloud-Radio Access Networks

A fronthaul design for current and future mobile networks based on the transport of sampled radio signals from/to base station baseband processing units (BBUs) to/from remote radio heads (RRHs), is presented. The design is a pure-Ethernet switched architecture that uses virtual local area network (VLAN) identifiers for the RRHs and flow identifiers for the antenna ports, and is compatible with current standardization definitions. A comprehensive analysis for the limits of the Ethernet fronthaul in terms of the total number of antennas that can be supported is carried out, based on the latency imposed by the Ethernet network. The analysis assumes the transportation of control and management (C&M) and timing information (based on the precision-time protocol, PTP) but is valid for other types of background traffic (for example, that generated by the implementation of different longterm evolution (LTE) functional subdivisions, in a fronthaul with mixed processing). A low-cost testbed using “smart SFP” in-line probes is presented and used to obtain measurements from an Ethernet fronthaul, transporting mixed traffic. The measurements show how background traffic affects hybrid-automatic repeat request (HARQ) retransmissions, and are used to validate the analysis. The effects of contention of PTP packets is discussed and a simple solution to overcome the effects of contention is proposed

Scheduling in an Ethernet Fronthaul Network

This paper investigates and compares the performance of different scheduling techniques in an Ethernet fronthaul network in the presence of both time-sensitive/high priority and background traffic streams. A switched Ethernet architecture is used as the fronthaul section of a cloud radio access network (C-RAN) and a comparison of two scheduling schemes, strict priority scheduling and time-aware shaping, is carried out. The different streams are logically separated using virtual local area network identifiers and contend for the use of trunk links formed between aggregator/switch nodes. The scheduling schemes are applied in the access and trunk ports in the fronthaul, and need to handle the queue management and prioritization of the different streams. In such cases, contention induced latency variation has to be characterized, especially when the fronthaul transports precision time protocol traffic, as it directly leads to errors in timestamping. OPNET models for strict priority and time-aware schedulers have been built and employed, and simulation results are used to compare the performance of the two scheduling schemes