## 1 Introduction
### Our Contributions  
The previous generation of networks with distributed antenna systems exploited spatial diversity to improve spectral efficiency, continuing in the current generation of networks. However, in this paper, we provide novel contributions in the state of the art of 5G beyond communication, and extensively investigate the performance of proposed spatial diversity transmission techniques considering interference and cooperation strategies to achieve URC for critical machine type communication networks. We further extend [35] introducing one more transmission scheme TAS with silencing and attain-close form expression of outage probability. Furthermore, we analyze the expected value of the signal-to-interference ratio (SIR), energy efficiency (EE), and throughput-reliability trade-off. We evaluate the performance and resource usage among the considered transmission schemes. We remark that ensuring high reliability using multiple node redundant transmission is also included in the study of enhancements for URLLC support in the 5G Core network in 3 GPP (Release 16) [36]. The major contributions are summarized as follows:  
* We analyze UE's performance when operating under full interference, silencing, TAS with silencing, and MRT in terms of the outage probability. We attain the accurate closed-form expressions of the outage probability for the distribution of the SIR of each scheme.
* We calculate the expected value of SIR and attain closed form solutions for each scheme. We show that MRT has higher SIR compared with the other schemes, whereas silencing and TAS with silencing show similar SIR with the same number of cooperating RRHs.
* We address the rate control problem constrained by target reliability constraints for the proposed schemes. We show that for all considered schemes, transmission rate increases with the increase in cooperating RRHs, while MRT offers a higher transmission rate among them for the same target reliability and for the same number of cooperating RRHs.
* We test energy efficiency (EE) for each scheme. We show that EE for all considered schemes increases with an increase in the cooperating RRHs, while MRT schemes have higher EE among considered schemes for the same target reliability and with the same number of cooperating RRHs.
* We analyze the minimum number of cooperating RRHs required to achieve a certain reliability level for all these considered schemes. We show that for the same number of cooperating RRHs, the MRT scheme achieves higher reliability levels. In contrast, this level is unattainable with other schemes.
* Finally, we analyze the trade-off between average system throughput and reliability to test CRAN network-level performance with considered transmission schemes through Monte Carlo simulations. We show that MRT attains a higher reliability level for the same number of cooperating RRHs with reduced throughput than the silencing and TAS.  
The rest of the paper is organized as follows. Section 2 explains the system model and highlights the main assumption along with transmission schemes. Section 3 presents the definition of diversity and reliability, outage formulation, rate control, energy efficiency, and throughput-reliability trade-off analysis under reliability constraints. Section 4 shows numerical analysis. Finally, Section 5 concludes the paper.  
Notation: Uppercase and lowercase letters denote random variables (RVs) and their realizations, unless stated otherwise. The probability density function (PDF) and cumulative distribution function (CDF) of RV \(X\) is denoted by \(f_{X}(x)\) and \(F_{X}(x)\), respectively. \(\mathbb{E}[.]\) denotes the expectation operation. \(X\sim\text{Exp}(1)\) is an exponential RV with the \(F_{X}(x)\!=\!1-e^{-x}\), while \(Y\sim\Gamma(n,\frac{1}{n})\) with \(f_{Y}(y)=\frac{y^{n-1}\exp^{-y}}{(n-1)!}\). Additionally, \(\Gamma(p,x)\!=\!\int_{x}^{\infty}t^{p-1}e^{-t}dt\) is the upper incomplete gamma function, and \({}_{2}F_{1}(a,b;c;d)\) denotes the Gaussian polarized hypergeometric function [37].