Self-secure feedback control based scheme for ultra-reliable and low-latency communication

5G is envisaged to support diverse use cases and applications. Enhanced Mobile Broadband (eMBB) and Ultra-Reliable and Low Latency Communications (URLLC) have been identified as two main communication scenarios in 5G. Unlike eMBB service which demands high data rate, URLLC has stringent latency and reliability requirement. Due to the sporadic and stochastic characteristics of URLLC traffic, an URLLC transmission may suddenly occurs during the transmission of eMBB data. It is sometimes necessary to transmit URLLC data on the resources occupied by eMBB. Thus in this paper, we investigate the dynamic downlink multiplexing for eMBB and URLLC data on the same time/frequency resource. Specifically, we present a dynamical puncturing scheme, which allows URLLC data occupy part of the radio resource that has been scheduled to ongoing eMBB transmission. The puncturing will degrade the performance of the eMBB traffic, therefore we introduce the signal space diversity (SSD) scheme into the proposed dynamic puncturing scheme. The decoding performance of eMBB data over the fading channel is thus improved through the component interleaving and rotation modulation. Furthermore, we derive the optimal rotation angel that can achieve the optimal puncturing performance by maximizing the average mutual information (AMI). The link-level simulation results show that the proposed scheme outperforms existing strategy, and the performance gain is around 1dB when the code rate is set as $2/3$. This observation also validates the theoretical analysis based on the AMI.

An ultra-reliable and low latency communications assisted modulation based non-orthogonal multiple access scheme

This paper studies the coexistence of enhanced mobile broadband (eMBB) and ultra-reliable and low-latency communication (URLLC) services in a cellular network that is assisted by a reconfigurable intelligent surface (RIS). The system model consists of one base station (BS) and one RIS that is deployed to enhance the performance of both eMBB and URLLC in terms of the achievable data rate and reliability, respectively. We formulate two optimization problems, a time slot basis eMBB allocation problem and a mini-time slot basis URLLC allocation problem. The eMBB allocation problem aims at maximizing the eMBB sum rate by jointly optimizing the power allocation at the BS and the RIS phase-shift matrix while satisfying the eMBB rate constraint. On the other hand, the URLLC allocation problem is formulated as a multi-objective problem with the goal of maximizing the URLLC admitted packets and minimizing the eMBB rate loss. This is achieved by jointly optimizing the power and frequency allocations along with the RIS phase-shift matrix. In order to avoid the violation in the URLLC latency requirements, we propose a novel framework in which the RIS phase-shift matrix that enhances the URLLC reliability is proactively designed at the beginning of the time slot. For the sake of solving the URLLC allocation problem, two algorithms are proposed, namely, an optimization-based URLLC allocation algorithm and a heuristic algorithm. The simulation results show that the heuristic algorithm has a low time complexity, which makes it practical for real-time and efficient multiplexing between eMBB and URLLC traffic. In addition, using only 60 RIS elements, we observe that the proposed scheme achieves around 99.99% URLLC packets admission rate compared to 95.6% when there is no RIS, while also achieving up to 70% enhancement on the eMBB sum rate.

In 6G networks, integrated sensing and communication (ISAC) is envisioned as a key technology that enables wireless systems to perform joint sensing and communication using shared hardware, antenna(s) and spectrum. ISAC designs facilitate emerging applications such as digital twins, smart cities and autonomous driving. Such applications also demand ultra-reliable and low-latency communication (URLLC), a feature that was first introduced in 5G and is expected to be further enhanced in 6G. Thus, an ISAC-enabled URLLC system can prioritize critical and time-sensitive targets and ensure information delivery under strict latency and reliability constraints. We propose a bi-static multiple-input multiple-output (MIMO) ISAC system to detect the arrival of URLLC messages and prioritize their delivery. In this system, a dual-function base station (BS) communicates with a user equipment (UE) and a sensing receiver (SR) is deployed to collect echo signals reflected from a target of interest. The BS regularly transmits messages of enhanced mobile broadband (eMBB) services to the UE. During each eMBB transmission, if the SR senses the presence of a target of interest, it immediately triggers the transmission of an additional URLLC message. To reinforce URLLC transmissions, we propose a dirty-paper coding (DPC)-based technique that mitigates the interference of both eMBB and sensing signals. To decode the eMBB message, we consider two approaches for handling the URLLC interference: treating interference as noise (TIN) and successive interference cancellation (SIC). For this system, we formulate the rate-reliability-detection trade-off in the finite blocklength (FBL) regime by evaluating the communication rate of the eMBB transmissions, the reliability of the URLLC transmissions and the probability of the target detection. Our numerical analysis show that our proposed DPC-based ISAC scheme significantly outperforms power-sharing based ISAC and traditional time-sharing schemes. In particular, it achieves higher eMBB transmission rate while satisfying both URLLC and sensing constraints.

Carrier frequency offset (CFO) and channel equalization are two critical problems for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless communication systems in ultra-reliable and low latency communication (URLLC). In this paper, we propose a semi-blind precoding aided structure that includes two CFO estimation approaches and an independent component analysis (ICA) based equalization scheme for MIMO OFDM systems in URLLC, requiring no pilots. We design a non-redundant balanced precoding strategy, killing two birds with one stone, where reference signals are superimposed into source signals to simultaneously allow CFO estimation and ambiguity elimination in the ICA-equalized signals. The proposed precoding-aided CFO estimation approach performs by maximizing a cost function formulated via the cross-correlations between the reference signal and the received signal. We further propose a low-complexity closed-form CFO estimation approach, by transforming the formulated cost function into a new expression. To maximize bit error rate (BER) performance, particle swarm optimization (PSO) is employed to perform the joint optimization of precoding constant and the number of OFDM blocks for CFO estimation, while avoiding exhaustive search. The proposed semi-blind precoding-aided structure provides a trade-off between performance, complexity and spectral efficiency for MIMO OFDM systems in URLLC.

The coexistence of Ultra-Reliable and Low-Latency Communications (URLLC) and enhanced Mobile BroadBand (eMBB) brings significant challenges for service pairing and resource allocation in beyond fifth-generation (B5G) wireless networks. To meet the reliability requirement of URLLC services and improve the fairness of eMBB services, we first develop a supervised learning-based resource allocation policy for eMBB services. Then, a two-phase resource allocation framework is proposed for URLLC services: 1) eMBB/URLLC service pairing, and 2) URLLC resource allocation. In the first phase, matching theory pairs eMBB and URLLC services for better fairness. In the second phase, URLLC resource allocation policy is optimized by a constrained unsupervised learning algorithm. Simulation results show that our proposed framework can achieve better trade-offs among fairness, throughput, and reliability compared with two existing baselines. For example, a dynamic proportional fairness algorithm can meet the reliability requirement of URLLC when its average packet arrival rate is below 0.7 packets/mini-slot. The proposed algorithm can support URLLC services with an average packet arrival rate of 1.6 packets/mini-slot

With the emerging commercial deployments of 5G Network, the Mobile Network Operators (MNOs) will be able to offer more significant network capabilities such as efficient ultra-reliable and low latency communications (URLLC), higher bandwidth for data transfer with enhanced Mobile Broadband (eMBB), and massive capacity to connect devices with massive Internet of Things (mIoT). MNOs are making huge investments to setup 5G Networks with an anticipation of growth in their revenues. However, MNOs may not see the return of investment through end user consumer base alone and may need additional revenue streams. Thus, 5G system has been designed to have advanced built-in features such as network slicing and edge computing, considering requirements from enterprise segments or vertical industries including healthcare, automotive, smart factories, mission critical communications, etc. To enable more rapid deployment of vertical services, the 5G deployments require fostering innovation at the application layer. With the growing needs of verticals industries, the operators are now focusing on enabling standards for vertical applications in 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> Generation Partnership Project (3GPP), a global standards forum for 5G. In this paper, the authors explain the Service Enabler Architecture Layer (SEAL) standard for 5G verticals and the services offered by the enabler layer. The paper also elaborates how the operators can leverage the SEAL to quickly develop and deploy vertical applications over the 5G Network.

The Ultra-Reliable and Low-Latency Communication (URLLC) for the fifth generation (5G) telecommunications is challenged by its high requirements on latency and reliability. Grant-free (GF) transmissions are known to be beneficial to reduce the latency for uplink by omitting the process of scheduling request and grant configuring. However, the reliability cannot be guaranteed due to the possible collisions among users. In this work, we propose uplink GF transmissions with Non-Orthogonal Coded Access (NOCA) for sporadic short packets withProactive retransmission scheme to meet URLLC requirements. The NOCA system contains the symbol spreading with low cross-correlation QPSK-based sequences at the transmitter and the Parallel Interference-Cancellation (PIC) mechanism at the receiver. System level simulations of NOCA are carried out to evaluate the possibility of employingReactive and Proactive retransmission schemes for URLLC services. The simulation results support that along with theProactive transmission scheme, NOCA can reduce the packet loss rate while achieving low latency. A spreading length adaptation strategy is also put forward for the proposed scheme in different scenarios.

In this paper, we investigate the secrecy performance of short-packet transmissions in ultra-reliable and low-latency communications (URLLC). We consider the scenario where a multi-antenna source communicates with a single-antenna legitimate receiver requiring ultra-high reliability and low latency, in the presence of a single-antenna eavesdropper. In order to safeguard URLLC, the source transmits the artificial noise (AN) signal together with the confidential signal to confuse the eavesdropper. We adopt a lower bound on the maximal secrecy rate as the secrecy performance metric for short-packet transmissions in URLLC, which takes the target decoding error probabilities at the legitimate receiver and the eavesdropper into account. Using this metric, we first derive a compact expression of the generalized secrecy outage probability (SOP). Then, we formally prove that the generalized SOP is a convex function with respect to the power allocation factor between the confidential signal and the AN signal. We further determine the optimal power allocation factor that minimizes the generalized SOP. The results presented in this work can be useful for designing new secure transmission schemes for URLLC.

Inspired by the new and dominating traffic services - ultra-reliable and low latency communications (URLLC), finite blocklength coding (FBC) has been developed to support delay and error-rate bounded quality-of-services (QoS) provisioning for time-sensitive wireless applications by using short-packet data communications. On the other hand, the age of information (AoI) has recently emerged as a new dimension of QoS performance metric in terms of the freshness of updated information. Since the status updates normally consist only of a small number of information bits but warrant ultra-low latency, exploring AoI in the finite blocklength regime creates another promising solution for supporting URLLC services. However, how to efficiently integrate and implement the above new techniques for statistical delay and error-rate bounded QoS provisioning in the finite blocklength regime has neither been well understood nor thoroughly studied. To overcome these challenges, we propose the AoI-driven statistical delay and error-rate bounded QoS provisioning schemes which leverage the AoI technique as a key QoS performance metric to efficiently support URLLC in the finite blocklength regime. First, we build up the AoI-metric based modeling frameworks in the finite blocklength regime. Second, we apply the stochastic network calculus (SNC) to characterize the upper-bounded peak AoI violation probability. Third, we jointly optimize the peak AoI violation probability and ∊-effective capacity and characterize their tradeoff in supporting statistical delay and error-rate bounded QoS provisioning for URLLC. Finally, we conduct the extensive simulations to validate and evaluate our developed schemes in the finite blocklength regime.

Future mobile communication systems need to support wide variety of new services and applications. In order to support these, ITU-R introduced new types of use cases. One such use case, called ultra reliable and low latency communication (URLLC), concerns the reduction of latency down to a millisecond level while ensuring the reliability of the transmission. In case of uplink transmission, supporting the stringent latency requirement of URLLC is quite challenging due to a time-consuming and complicated handshaking process. In the time division duplexing (TDD) systems, satisfying the latency requirement is far more difficult since the mobile device cannot transmit the data when the subframe is directed to the downlink. In this paper, we propose a new grant signaling scheme, referred to as channel-aware sparse signaling (CASS), to achieve a low latency access in the TDD-based URLLC systems. Key idea of CASS is to map the grant information into a small number of subcarriers and then decode it using a small number of early received samples. From the numerical evaluations, we demonstrate that the proposed CASS scheme achieves significant reduction in access latency over the conventional LTE-TDD systems.

The 5G network slicing using SDN based technology for managing network traffic

5G mobile networks are envisioned to support ultra-reliable and low latency communications (URLLC), which is targeted for a packet transmission with 99.999% reliability and a user plane latency down to 0.5 ms. In this paper, a reliability model and a latency model for URLLC traffic are presented, along with some deterministic analysises providing the reliability requirements for each physical channels and the feasible nu-merologies for URLLC transmission. Meanwhile, system-level simulation is conducted with two metrics including the 5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> percentile downlink and uplink Signal-to-Interference-and-Noise Ratio (SINR) values and the percentage of users satisfying the reliability and latency requirements. Furthermore, a resource selection based structure for physical uplink control channel (PUCCH) that satisfies the deterministic analysis is proposed and evaluated with link-level simulation, which shows the reliability can be met at the 5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> percentile uplink SINR value provided by system-level simulation.

Ultra-reliable and low-latency communication (URLLC) is expected to lead AR/VR, factory automation, transport industry, and power distribution as an important requirement in 5G wireless networks. This class of services could be considered as the most challenging and intriguing part because achieving low latency and ultra-high reliability at the same time is hard. In the 3rd Generation Partnership Project(3GPP) standard, a general URLLC requirement is 99.999% target reliability with 1 ms (two-way) user-plane latency. The reliability here is defined as the percentage of packets that are correctly received within the delay budget. In this paper, a relay selection algorithm based on the Finite Blocklength (FBL) regime is proposed to satisfy high reliability and low latency required in URLLC of 5G systems, using the genetic algorithm (GA). The simulation results showed better performance of the proposed algorithm than of the fixed relay selection.

To tackle the problem of transmission uncertainty for ultra-reliable and low-latency communication (URLLC) in unlicensed band, existing studies have proposed many channel reservation based schemes categorized into single-channel reservation and multi-channel reservation schemes. The schemes integrate the full duplex radio and orthogonal busy tone technologies to reserve URLLC channel. URLLC channel reservation is accomplished by all URLLC devices continuously sending busy tones on the URLLC channel. Compared to the multi-channel reservation scheme, the single-channel reservation scheme is more friendly to the heterogeneous system, such as Wi-Fi, but it generates an unsatisfactory probability of successful channel reservations as it is difficult to find the common single channel for all URLLC devices especially when the traffic load of unlicensed band is above a certain level. This paper proposes a progressive single channel reservation (P-SCR) scheme to promote the success probability of channel reservation by relaxing simultaneousness restriction of URLLC channel reservation. The P-SCR scheme allows user equipment to reserve the common URLLC channel in a progressive manner and introduces an advanced preparation time to improve channel utilization and probability of successful URLLC channel reservations. The performance evaluation results showed that the proposed P-SCR scheme obviously outperforms the existing single- and multi-channel reservation schemes in terms of the probability of successful channel reservation.