This paper analyzes the performance of an intelligent reflecting surface (IRS)-aided short-packet communication system over Nakagami- $m$ fading channels. In this system, the base station adopts non-orthogonal multiple access (NOMA) to transmit to a near user and a far user, and its transmission to the far user is aided by the IRS. Both continuous phase shifts (CPSs) and discrete phase shifts (DPSs) are considered for the IRS. By using order statistic and moment matching, we approximate the end-to-end channel gain to follow the Gamma distribution and then derive the approximate closed-form expressions for the average block error rate (BLER) in the high signal-to-noise ratio (SNR) regime and then conduct a refined analysis of the interplay among the minimum common blocklength, optimal power allocation, and the related parameters of IRS (e.g., the number of elements of the IRS) for achieving target BLERs at two users. Finally, numerical and simulation results demonstrate the accuracy of theoretical analysis. They also show that the IRS-aided short-packet NOMA system outperforms the system without IRS, and that DPSs with 3-bit quantization achieve a similar performance as the optimal CPSs.

In this paper, we give performance analysis in an unmanned-aerial-vehicle (UAV) assisted ground short-packet communication system, which adopts a UAV as a wireless relay to accomplish ultra-reliable and low-latency communications (URLLC) between a base station and a user equipment (UE). Both large-scale fading, which is modeled as the free space path loss or the classic 3-Dimensional channel, and small-scale fading, which follows Nakagami- $m$ distribution, are considered in our system model. We first derive the closed-form expressions for the average overall block error ratio (BLER) at the UE by adopting Gasssian-Legendre quadrature (GLQ) method. Then, under the reliability and latency constraints at the UE, we apply both bisection search and one-dimensional search algorithms to jointly optimize blocklength, transmit power and UAV flying height for maximizing the energy-efficiency (EE) of UAV. Finally, Monte-Carlo simulations are provided to verify our analytical results.

We analyze the benefits of simultaneous transmitting and reflecting intelligent reflecting surfaces (STAR-IRSs) for short-packet communications (SPC) with non-orthogonal multiple access (NOMA) and statistical channel state information towards ultra-reliable and low-latency communications. Considering Rician fading and energy splitting protocol, we analyze the performance of STAR-IRS aided NOMA SPC systems with continuous and discrete phase shifts. We first derive new closed-form expressions for the average block error rate (BLER) and diversity order in the finite signal-to-noise ratio (SNR) regime. We then determine the relationship among the average BLER, power allocation, blocklength, and transmission and reflection coefficients. Finally, Monte Carlo simulations are used to verify our theoretical analysis and examine the optimal transmission and reflection coefficients that minimize the common blocklength in the considered system under reliability constraints.

In this paper, a measurement-based three-dimensional (3-D) spatial modulation (SM) system is first proposed in the existing literature. The major contributions of this work include: 1) a 3-D SM measurement system with a $\boldsymbol{16 \times 16}$ virtual uniform rectangle array (URA) at the transmitter and a virtual uniform line array (ULA) with 16 elements at the receiver, 2) a comprehensive measurement activity indoors taking both line-of-sight (LOS) and none-LOS (NLOS) scenarios into account, and 3) the first measurement-based average bit error probability (ABEP) evaluation for 3-D SM system. Numerical results reveal that the widely used independent and identically distributed (i.i.d.) Rayleigh channel model significantly overestimates the performance of the SM system. Moreover, we find that the ABEP performance of 3-D SM is worse than that of the 2-D SM under the same spacing among the antenna array, while 3-D SM outperforms 2-D SM under the same size of the antenna array.

To unlock the full potential of next-generation networks, we investigate reconfigurable intelligent surfaces (RIS) assisted wireless communication systems, in which two full-duplex (FD) users simultaneously communicate via the space shift keying (SSK) technique. According to the channel state information, we investigate two schemes, i.e., intelligent phase-shift and blind phase-shift RIS-FD-SSK schemes. Then, we analyze the average bit error probability (ABEP) of the RIS-FD-SSK scheme employing a maximum likelihood detector. For the intelligent phase-shift scheme, the closed-form ABEP expressions are derived, and the exact approximating ABEP is obtained via the Gaussian-Chebyshev quadrature method. To gain more valuable insights, asymptotic ABEP is also provided in this paper. For the blind phase-shift scheme, we derive exact and upper bound ABEP expressions and asymptotic ABEP expression. Furthermore, the analytical derivation results are verified by Monte Carlo simulations. Results demonstrate that the proposed RIS-FD-SSK system outperforms the conventional half-duplex (HD) scheme in terms of ABEP as the capability of the loop-interference cancellation technique increases. Additionally, as the data rate enhances, the RIS-FD-SSK scheme can achieve better ABEP performance than the RIS-HD-SSK scheme.

This paper presents the performance analysis for the two-user downlink cooperative non-orthogonal multiple access (C-NOMA) short-packet communication (SPC) over Rayleigh channels. The near user acts as a relay, which operates in full-duplex (FD) mode and employs decode-and-forward protocol, to forward the information to the far user. Two kinds of residual self-interference (RSI) models, which are modeled as being free of fading and following Rayleigh fading, are considered. We first derive the approximate closed-form expressions of average block error rate (BLER) at both users under these two RSI models. Then, simulations are provided to verify the validity of our theoretical analysis. Finally, we evaluate the BLER performance difference between long-packet and short-packet transmissions for FD C-NOMA and that between FD relaying and HD relaying. The analysis and simulation results show that, for ultra-reliable and low-latency communication, we can use RSI link modeled as being free of fading to simplify the system analysis. Furthermore, compared to long-packet communication, for FD C-NOMA SPC have a narrow range of power allocation to achieve high-reliable transmission, and because BLER outperformance of FD relaying over HD relaying degrades when the RSI signal becomes strong, the optimal duplex mode for FD C-NOMA SPC is determined by the RSI signal and the target BLERs at both users.