**6. Conclusions**

*Array Pattern Optimization*

the values used in **Table 1**:

*Portion of log extracted by simulations.*

*GMAX*(θ<sup>0</sup> <sup>=</sup> <sup>45</sup>°

tion logs.

The simulations have been accomplished by using 20 different seeds and extracting the confidence intervals obtained by the repetitions considering a confidence level set to 95%. The traffic is represented by user datagram protocol (UDP) data packets randomly generated (based on the simulation seed) by different couples of nodes. The number of spatial streams is set to 8. Therefore, most of the antenna parameters including the number of elements and the spacing in the system are the same used in [26], with the only exception that we also provide the beam steering angle setting. For simulations, we considered such data rates provided by the IEEE802.11ac standard in function of the number of spatial streams. In order to validate the model, the first test consists of the analysis of such run simula-

**Figure 15** represents a portion of log extracted by a randomly chosen simulation run related to the case of URPA; the result of the log is printed on the console perspective of *Omnet*++; the red rectangle highlights the main line of the log, which displays the result of the computed gain in function of the current angle; the main line synthesizes that the value of the gain corresponding to the angle of 43.59° is 41.96 dB; considering the steering angle of 45°, we can manually compute the maximum gain that is the gain corresponding to the maximum radiation angle (thus the steering angle) by using Eq. (10) and replacing the terms of the equation with

,ϕ) <sup>=</sup> <sup>4</sup>*<sup>π</sup>* <sup>×</sup> <sup>90</sup><sup>2</sup> \_\_\_\_\_\_\_

where δθ0 represents the attenuation in dB related to the steering angle with respect to the maximum gain corresponding to *θ0* = 0° (which is 42.39 dB). In Eq. (13), the value of 772.97 at the denominator is the result of the double integral computed by the simulator, using the Simpson method [33]. The gain value of

Antenna model Massive MIMO URPA/HPA/CPA

Num. of elements 90 (URPA), 91 (HPA), 91 (CPA)

Network standard IEEE802.11ac

Channel bandwidths [MHz] 20, 40, 80, 160 Data rates [Mbps] from 57.8 to 6933.3

Steering angle 45° Elem. spacing 0.5 λ Carrier freq. 5 GHz

Traffic data type UDP Sim. area size 500 × 500 m Sim. time 300 s

772.97 <sup>−</sup> δθ<sup>0</sup> <sup>=</sup> 42.16 *dB* (13)

**102**

**Table 1.**

**Figure 15.**

*Main simulation parameter set.*

This chapter illustrated the most recent research works in the simulation field about SAS and planar massive MIMO 5G technologies, with the aim to make an overview about research advances accomplished in this context. In this regard, after a brief analysis, useful for providing a minimum of theoretical knowledge about these kinds of technologies and applications, the chapter illustrated some aspects of the latest related works in this area. Relative to the experimental and practical analysis, one of the most used simulation tool, that is the Omnet++ simulator, has been considered. In this respect, it has been highlighted that, by modifying the default physical operations provided by the simulator in terms of power management, modulations and channel propagation model and at the same time, by designing a proper SAS or massive MIMO antenna module, it is possible to emulate a wireless network scenario consistent with the latest 5G standard specifications. Nevertheless, it also highlighted that, for enabling the simulator to support these kinds of technologies, it is required to implement the specifications defined by the most recent IEEE standards such as the 802.11n and 802.11ac to establish an interconnection between the logical operations and the physical simulation resources.

*Array Pattern Optimization*
