Byzantine fault-tolerant (BFT) state machine replication (SMR) is adopted to support blockchain consensus by tolerating arbitrarily faulty behaviours. However, the inherent complexity of BFT protocols makes existing BFT protocols hard to adapt to large-scale applications that require high scalability and performance. In this paper, we propose a BFT parallelism protocol designed to enhance its scalability by using a hierarchical multi-committee architecture. It also encompasses a cross-layer consensus operation flow to improve safety and support trusted execution environments (TEEs). Our proposed approach allows the lower bound on the number of peers to be reduced to$2f+1$. We show the value of our proposed protocol in comparison to other state-of-the-art BFT protocols through experiments and performance evaluations on a testbed built on a cloud platform. The proposed protocol demonstrates a remarkable level of scalability, capable of accommodating a growing number of peers. Additionally, it exhibits improved performance when contrasted with HotStuff and FastBFT, with approximately 100% and 200% enhancements, respectively.

We present part of Huawei's efforts in building a Product Knowledge Graph (PKG). We want to identify which product attributes (i.e. properties) are relevant and important in terms of shopping decisions to product categories (i.e. classes). This is particularly challenging when the attributes and their values are mined from online product catalogues, i.e. HTML pages. These web pages contain semi-structured data, which do not follow a concerted format and use diverse vocabulary to designate the same features. We propose a system for key attribute identification (KATIE) based on fine-tuning pre-trained models (e.g., DistilBERT) to predict the applicability and importance of an attribute to a category. We also propose an attribute synonyms identification module that allows us to discover synonymous attributes by considering not only their labels' similarities but also the similarity of their values sets. We have evaluated our approach to Huawei categories taxonomy and a set of internally mined attributes from web pages. KATIE guarantees promising performance results compared to the most recent baselines.

Byzantine fault-tolerance (BFT) consensus is a fundamental building block of distributed systems such as blockchains. However, implementations based on classic PBFT and most linear PBFT-variants still suffer from message communication complexity, restricting the scalability and performance of BFT algorithms when serving large-scale systems with growing numbers of peers. To tackle the scalability and performance challenges, we proposeParBFT, a new Byzantine consensus parallelism scheme combining classic BFT protocols and a novel Bilevel Mixed-Integer Linear Programming (BL-MILP)-based optimisation model. The core aim of ParBFT is to improve scalability via parallel consensus while providing enhanced safety (i.e. ensuring consistent total order across all correct replicas). Another core novelty is the integration of the BL-MILP model into ParBFT. The BL-MILP allows us to compute optimal numerical decisions for parallel committees (i.e. the optimal number of committees and peer allocation for each committee) and improve consensus performance while ensuring security. Finally, we test the performance of the proposed ParBFT on Microsoft Azure Cloud systems with 20 to 300 peers and find that ParBFT can achieve significant improvement compared to the state-of-the-art protocols.

Small Cells (SCs) are considered as a key enabling technique for future 5G cellular networks; whether they are deployed for Macro Cells networks densification or ensuring a standalone broadband access service. However, one of the critical challenges facing SCs deployments is a stable and an economical backhaul network. Particularly, if we consider SC for green-field deployments where operator transport infrastructure is bad or absent. Indeed, the question that arises in this specific case: what is the backhaul design that best meets economic constraints and end users Quality of Service (QoS) requirements? In this paper, we propose a novel method to design a cost-efficient SCs backhaul for green field deployment, while respecting linking technologies constraints. In fact, we formulate the problem of backhaul planning as a Mixed Integer Linear Programming (MILP), wherein the objective is to minimize SCs-Core Network connection cost while providing necessary access to operator mobile broadband by using a set of different technologies. Implementation results corroborate the benefit of wireless backhaul over wired one, and give to mobile operator insightful guidelines for designing a SCs backhauls for green field deployment.

High smartphone penetration and Average Revenue Per User (ARPU) growth imply a quick and good broadband services delivery. In this context, Mobile Networks Operators (MNOs) have to satisfy current subscribers and gain new ones. Small Cells (SCs) are a promising alternative to MNOs to reach emerging markets and meet the rising mobile broadband demand. However, most of those competitive markets have to be served with wireless transport infrastructures for economic reasons; yet wireless links have limited data rates. SCs backhaul should be carefully planned. For this purpose, SCs backhaul dimensioning must take into account required end users traffic flows. As those throughputs vary according to different users traffic profiles, what are the necessary backhaul links capacities to satisfy them and don't exceed MNO budget. In this paper, we analyze UEs activity effect on issued traffic flows on a SC logical interfaces (S1 and X2) by using a Markov chain. We make difference between user and control plane throughputs. Numerical results showed how UEs activity increases generated traffic on S1 interface, but its impact is barely noticed on X2 interface traffic. It is due to the fact that data exchanges are primarily done on S1 interface, whereas signalization flows are minority parts in both S1 and X2 interfaces.

One of the key enablers of the upcoming IEEE 802.11ax standard is the inclusion of uplink multi-users (UL MU) transmission model, which is performed using multiple-input multiple-output (MIMO) and beamforming techniques. So far, UL MU-MIMO has not been standardized in any of IEEE 802.11 amendments, because of technical issues facing its definition. One of these significant issues is the scheduling of UL MU-MIMO transmissions, which refers to selection rules and resource allocation procedures performed before simultaneous data transmissions. Indeed, simultaneous transmitters and receiver should exchange some information to correctly transmit the parallel data frames. However, this information exchange adds overheads, leading to reduce network performance. In this regard, we have proposed, in a previous work, a novel 802.11ax medium access control protocol aiming at reducing elapsed time in managing the establishment of an UL -MU communication called Wait-to-Pick-As-Available (W2PAA). Our contribution in this paper is twofold. First, we introduce an analytical model based on semi-Markov Chains to evaluate the performance of W2PAA; taking into a detailed behavior of the backoff counter (i.e. freezing period). Second, we propose an enhanced version of W2PAA aiming at improving both system and user-oriented performances. Aiming at validating the analytical model and comparing the performance of both versions of W2PAA, we used computer simulation. Obtained results, validate the analytical model in one hand, and clearly indicated the gain of both W2PAA versions by report to the basic UL-Single User on the other hand. Copyright © 2016 John Wiley & Sons, Ltd.

Uplink multi-users (UL-MU) transmissions are the key solution for the next IEEE 802.11ax to fully benefit from spatial resources. In this context, it is important to bring optimized solutions to address the technical challenges associated with UL-MU, particularly, issues associated to the management of multiple packets reception in the MAC layer. In this paper, we propose a novel 802.11ax MAC protocol aiming at reducing elapsed time in managing the establishment of an UL-MU communication, which would enhance system performance. Further, an analytical model, based on semi-Markov chains is proposed to evaluate the performance of the proposed protocol. Obtained results show notable system performance compared to Single User (SU) transmission.