## 3 Framework
### Architecture
#### 3.1.2 Experiments and Measurements  
Several services can be launched as test scripts or experiments, depending on the application that needs to be dived into. Then, the vUE logs will have to be attached and timestamps matched and merged. In Table 1 the most relevant KQIs (describing quality of an end-to-end service in parameters that an end-user may directly experience) for various types of services (File Transfer Protocol (FTP), web (HyperText Transfer Protocol or HTTP), NetTest speed test [38] and video streaming) are shown. Each experiment could collect several of these services and indicators, or parts of them, depending on the relevant needs. Figure 1: A high level diagram of the vUE probe framework. Such samples could optionally be labeled based on learning algorithms and based on previous samples. However this is not necessary in the first instance and could be used offline in both supervised and unsupervised learning algorithms. In this way, the Web KQI parameters are defined as follows:  
* First Paint: Time since the browser starts to render the page and shows the first hint of content on the screen. This is a good front-end benchmark of when a page appears to be starting to load. * Page Load Time: Time it takes for the entire content of a web page to be downloaded and displayed in the browser. * Fully Loaded Time: Time until there is 1.5 s of network inactivity after on-load, waiting up to a maximum of 5 s.  
Regarding the FTP, the main KQI definitions are the following:  
* Setup Time: denotes the time period needed to establish a connection to the FTP server, from sending the initial query to a server until the first data packet is received. * Speed download: capacity to fully transmit a file of a given size per time unit. Finally the ping service would have a single KQI:  
* RTT: round trip time (RTT) or round trip latency, or simply response time, is the time from the sending of an ICMP packet to it being received again. With respect with radio environment parameters, the most important parameters that could be obtained from a MODEM log are summarized in Table 2. Among these, the highlighted parameters are defined as follows. * RSRP is the power of a reference received signal at the userside. Its value range is between \(-140\) and \(-40\) dBm approximately. * RSRQ is a quality metric of the radio channel that is a ratio of RSRP and the total received signal power (as the sum of interference and noise) ranging between \(-19.5\) and \(-3\) dB. \begin{table}
\begin{tabular}{l l l} \hline \hline
**Application** & **KQIs** & **Other Parameters** \\ \hline \multirow{3}{*}{Hyper Text Transfer Protocol (HTTP)} & First Paint (ms) & Page Timings \\ \cline{2-3}  & Page Load Time (ms) & Navigation Timings \\ \cline{2-3}  & Fully Loaded Time (ms) & Resource Timings \\ \hline \multirow{3}{*}{File Transfer Protocol (FTP)} & Setup Time (s) & \\ \cline{2-3}  & Total time (s) & N/A \\ \cline{2-3}  & Speed Download (Mbps) & \\ \hline \multirow{3}{*}{NetTest} & DL/UL Throughput (kbps) & \\ \cline{2-3}  & Resolution Time DL/UL (ns) & N/A \\ \cline{2-3}  & Total bytes DL/UL & \\ \hline Ping & RTT (ms) & N/A \\ \hline \multirow{3}{*}{Video Streaming} & Initial Delay (s) & \\ \cline{2-3}  & Goodput (Mbps) & Highest quality used \\ \cline{1-1} \cline{2-3}  & Number of Stallings & Most used quality \\ \cline{1-1} \cline{2-3}  & Number of up down quality switch & Time spent per quality \\ \cline{1-1} \cline{2-3}  & Buffer size (bits) & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Key quality indicators of the service tests. The experiments can be scheduled according to specific purposes (for instance, to reproduce a logging error at a given base station or to check for a sudden drop in performance at a specified time) or periodically according to a survey plan. Hence, these configurations can be set depending on the specific needs for the purposes intended. Then the corresponding logs are sent by Secure SHell (SSH) to a Structured Query Language (SQL) database where they can be aggregated or examined online.