Non-Asymptotic Performance for Finite Blocklength Coding Over Nakagami-m Channels

NOMA-based UAV system under finite blocklength regime with analysis in Rician fading channel

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.

This paper considers simultaneous wireless information and power transfer (SWIPT) mechanisms in a relaying network with finite blocklength (FBL) codes. The reliability of the network is optimized under both a power splitting (PS) protocol and a proposed joint PS and time switching (TS) protocol. Under both protocols, we first determine the overall error probability formulation of the SWIPT-enabled two-hop transmission in the FBL regime. Subsequently, we state and solve optimization problems minimizing the overall error probability. Via numerical analysis, we show the appropriateness of our analytical model and demonstrate the performance advantage of the proposed protocol in comparison to TS and PS protocols. In addition, we provide interesting insights on the system behavior by characterizing the impact of the blocklength, transmit power and packet size on the reliability performance.

Secure ultra-reliable low-latency communication (URLLC) has been recently investigated with the fundamental limits of finite block length (FBL) regime in mind. Analysis has revealed that when eavesdroppers outnumber BS antennas or enjoy a more favorable channel condition compared to the legitimate users, base station (BS) transmit power should increase exorbitantly to meet quality of service (QoS) constraints. Channel-induced impairments such as shadowing and/or blockage pose a similar challenge. These practical considerations can drastically limit secure URLLC performance in FBL regime. Deployment of an intelligent reflecting surface (IRS) can endow such systems with much-needed resiliency and robustness to satisfy stringent latency, availability, and reliability requirements. We address this problem and propose to minimize the total BS transmit power by simultaneously designing the beamformers and artificial noise at the BS and phase-shifts at the IRS, while guaranteeing the required number of securely transmitted bits with the desired packet error probability, information leakage, and maximum affordable delay. The proposed optimization problem is non-convex and we apply block coordinate descent and successive convex approximation to iteratively solve a series of convex sub-problems instead. The proposed algorithm converges to a sub-optimal solution in a few iterations and attains substantial power saving and robustness compared to baseline schemes.

Both information age and delay are critical performance metrics of emerging time-sensitive applications. However, their inherent correlation in the finite block length (FBL) regime has remained uninvestigated as it is affected by block length and update rate in a complex manner. In this paper, closed-form expressions for average age of information (AoI), peak AoI (PAoI) and delay are derived for an FBL Last-Come First-Served system with retransmission and non-preemption policies, based on which a comprehensive analysis of the relationship among the three metrics in the FBL regime is presented. It is proved that there exists a strong tradeoff between delay and AoI/PAoI given a block length, and that AoI, PAoI and delay have positive correlation given an update rate, regardless of the weight. With the goal of minimizing delay and AoI simultaneously, the weighted sum of delay and PAoI (upper bound on AoI) is formulated and proved to be convex with respect to block length and update rate. A low-complexity optimization algorithm is developed with a closed-form expression of the optimal update rate, whose performance approaches the Pareto boundaries of the PAoI-delay and the AoI-delay regions, at much lower complexity than exhaustive search.

In this paper, we study a multiple-input single-output (MISO) assisted multi-user downlink network. To support low-latency communications, the transmissions to massive users are coded by finite blocklength (FBL) codes. For such network, an efficient power allocation design is provided to optimize the sum throughput. In particular, we first characterize the FBL throughput performance, following which a power allocation problem is formulated aiming at maximizing the sum throughput in the FBL regime. To address the formulated non-convex problem, we separate the complex expression of the objective function into two parts and then conduct different tight convex approximation methods, with which, an efficient successive convex approximation (SCA)-based approach is introduced. Simulation results validate our analytical model and reveal that the proposed approach converges effectively and achieve the performance close to results of the exhaustive search. Furthermore, we evaluate the impacts of blocklength, number of transmitter antennas, power constraints and number of users on the system performance.

Taking advantage of the broadcast nature of radio frequency (RF) wave propagation, simultaneous wireless information and power transfer (SWIPT) has recently gained significant research attention since it can prolong the battery-life of energy-constrained and low-power-supported mobile devices. In addition, due to the potential benefits of favorable propagation and channel hardening, cell-free (CF) massive multi-input multi-output (m-MIMO) can significantly enhance the QoS performance of SWIPT in terms of the achievable data rate and energy efficiency. On the other hand, finite blocklength coding (FBC) has been proposed to guarantee stringent QoS requirements while reducing the access latency using short-packet communications. However, how to efficiently integrate these new techniques using FBC based statistical delay-bounded QoS theory has imposed many new challenges not encountered before. To overcome these difficulties, in this paper we propose and develop statistical delay and error-rate bounded QoS provisioning schemes over SWIPT-enabled CF m-MIMO 6G wireless networks in the finite blocklength regime. In particular, we establish SWIPT-enabled CF m-MIMO based system models by using FBC. We also formulate and solve the optimization problems for the tradeoff between the E-effective capacity and harvested energy for our proposed statistical delay and error-rate bounded QoS provisioning mechanisms. The obtained simulation results validate and evaluate our developed schemes.

Age of information (AoI) is an effective measure of the information freshness for wireless networked control systems (WNCSs). However, the AoI performance for a closed loop of WNCS with two-way delays has remained unexplored, especially in the finite blocklength (FBL) regime. In this paper, we investigate the peak age of loop (PAoL) performances, including the average, variance and outage probability of PAoL, for WNCSs with FBL over fading channels. Their closed-form expressions are respectively derived regarding the blocklength and the maximum number of allowable transmissions. We prove that the average PAoL is less than the sum of the average peak AoI in uplink (UL) and downlink (DL) due to the coupling between UL and DL. We also show that there is a tradeoff between the average PAoL and the variance/outage probability of PAoL. Based on the comprehensive performance analysis, we study a PAoL-oriented communication and control co-design with an adaptation scheme for transmission power, blocklength and the maximum number of allowable transmissions. Simulation results verify the correctness of the analytical results and show that the proposed PAoL-oriented scheme significantly outperforms the UL only and DL only optimization schemes, with an up to 8-fold reduction in the average control cost.

A two-user downlink cooperative non-orthogonal multiple access (NOMA) short-packet communication network is investigated in flat Rayleigh fading channels, where a central user cooperatively relays the signals intended to a cell-edge user. To derive the average block error rate (BLER) of the central user, unlike the work in the literature where the product term is neglected, a new method that works well for the whole range of power allocation factor is proposed. Furthermore, the average BLER of the cell-edge user is theoretically derived. Numerical results demonstrate that while remaining almost the same average BLER for the central user, the cell-edge user in our proposed cooperative NOMA network achieves lower average BLER than those in the conventional NOMA network and the cooperative orthogonal multiple access network.

In this paper, we investigate a fifth generation cellular vehicle-to-everything based platoon system and propose low-complexity dynamic manager selection and resource allocation algorithms in the finite block length regime, to meet the ultra reliable and low latency communication requirements of intra-platoon safety-related data transmission. A closed-form expression for the platoon manager index is derived, based on which a low-complexity dynamic platoon manager selection algorithm is proposed, enabling a significant communication performance enhancement over the conventional head vehicle platoon manager algorithm. This is also the first work to investigate the impact of finite block length on platoon communication. The optimal finite block length coding rate under automatic repeat request retransmission is obtained. A subchannel multiplexing criterion is proposed and closed-form expressions for the optimal transmission powers of the platoon manager and its subchannel multiplexing partner are derived. Based on the theoretical findings, a joint resource allocation and coding rate optimization algorithm is proposed, achieving a near-optimal performance in terms of groupcast latency with a significant complexity reduction over exhaustive search.

The ultra-low latency requirements of emerging Internet of Things (IoT) applications necessitate data transmission in the finite blocklength (FBL) regime, while non-orthogonal multiple access (NOMA) enables massive connectivity. However, the practical imperfection of successive interference cancellation (SIC), a key component of NOMA, can significantly degrade system performance. This paper proposes the use of improper Gaussian signaling (IGS) to mitigate interference caused by imperfect SIC in an uplink NOMA system operating in the FBL regime. Specifically, users are grouped into pairs to form NOMA groups, where IGS is applied at the strong user in each pair to suppress residual interference. A minimum effective-throughput maximization problem is formulated by jointly optimizing user grouping, blocklength allocation, power allocation, IGS circularity coefficient, and decoding error probability. To address the resulting non-convex and mixed-integer nonlinear programming problem, we develop an efficient algorithm that achieves a high-quality suboptimal solution. Simulation results demonstrate that the proposed scheme with IGS-FBL outperforms various benchmark schemes, especially under severe imperfect SIC and stringent decoding error probability requirement conditions. Particularly, at a maximum decoding error probability of 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup>, the proposed scheme with IGS-FBL achieves the minimum effective-throughput that is 14.1×, 38.0×, and 98.8× greater than the benchmark schemes employing IGS-infinite blocklength (IGS-IFBL), proper Gaussian signaling-FBL (PGS-FBL), and PGS-IFBL, respectively.

This paper provides a framework for error rate performance analysis of M-ary phase-shift keying (MPSK) systems with improper phase estimation over some common fading channels obeying Rayleigh, Rician, or Nakagami-m distribution. In addition, the channel is also perturbed by additive white Gaussian noise (AWGN). The phase distortions considered in the paper are random, unbiased, i.e. having zero-mean, and follows Tikhonov distribution. Analytical average symbol error probability (SEP) is calculated through a new efficient method and plotted as a function of signal to noise ratio (SNR) for different values of the modulation order, M. Our approach relies upon knowledge of the moment generating function (MGF) of the received SNR. The resulting expression is an integral over a finite range of integrands containing only elementary functions. Extensive Monte Carlo simulations were performed to validate the theoretical results. Although the SEP can be computed via direct numerical integration, the MGF method performs far better because direct integration suffers from numerical instability and inaccuracy due to the presence of infinite integration limits or may contain complex mathematical functions.

In this paper, we consider a downlink multiuser network operating with finite blocklength codes under statistical quality of service (QoS) constraints. An optimal power allocation algorithm is studied to maximize the normalized sum throughput under QoS constraints. We first determine the finite blocklength (FBL) throughput formulations and subsequently state optimization problems. We show the convexity of the power allocation problem under certain conditions and propose an optimal algorithm to solve the problem. Via numerical analysis, we demonstrate the performance improvements with the optimal power allocation. In addition, we provide interesting insights on the system behavior by characterizing the impact of the error probability, the QoS-exponent and blocklength on the performance.

Effective Capacity (EC) indicates the maximum communication rate subject to a certain delay constraint while effective energy efficiency (EEE) denotes the ratio between EC and power consumption. In this paper, we analyze the EEE of ultra-reliable networks operating in the finite blocklength regime. We obtain a closed form approximation for the EEE in Rayleigh block fading channels as a function of power, error probability, and delay. We show the optimum power allocation strategy for maximizing the EEE in finite blocklength transmission which reveals that Shannon's model underestimates the optimum power when compared to the exact finite blocklength model. Further-more, we characterize the buffer constrained EEE maximization problem for different power consumption models. The results show that accounting for empty buffer probability (EBP) and extending the maximum delay tolerance jointly enhance the EC and EEE.

This paper is devoted to an investigation of an exact average symbol error probability (SEP) for amplify and forward (AF) relaying in independent Nakagami‐m fading environments with a nonnegative integer plus one‐half m, which covers many actual scenarios, such as one‐side Gaussian distribution (m = 0.5). Using moment generating function approach, the closed‐form SEP is expressed in the form of Lauricella multivariate hypergeometric function. Four modulation modes are considered: rectangular quadrature amplitude modulation (QAM), M‐ary phase shift keying (MPSK), M‐ary differential phase shift keying (MDPSK), and π/4 differential quaternary phase shift keying (DQPSK). The result is very simple and general for a nonnegative integer plus one‐half m, which covers the same range as integer m. The tightness of theoretical analysis is confirmed by computer simulation results.