# KQI Performance Evaluation of 3 GPP LBT Priorities for Indoor Unlicensed Coexistence Scenarios
## 4 Performance Indicators
### Fairness  
Another crucial aspect highlighted by 3 GPP is the concept of _fairness_ with respect to other wireless technologies operating in the same band. In this way, the standard defines it as the _capacity of a 3 GPP \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Service** & **Category** & **Parameter** & **Unit** & **Reference** \\ \hline \multirow{4}{*}{Real Time Video Streaming} & \multirow{4}{*}{KQI-Integrity} & Frame Loss Ratio & (\%) & [27] \\  & & Cumulative Jitter & (ms) & [28] \\  & & Frame end-to-end delay & (ms) & [28] \\  & & Peak signal-to-noise ratio (PSNR) & 0-5 & [29] \\ File Transfer Protocol (FTP) & KQI-Integrity & File Transfer average throughput & (Mbps) & [26] \\  & & File Transfer Delay & (s) & [26] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Service KQIs measured. network to not affect the active WiFi networks in one operator rather than an additional WiFi network operating in the same operator, in terms of throughput and latency [2]. In this respect, beyond the aforementioned 3 GPP definition, there is no defined unanimity for its objective assessment. In the following, we can find in the literature a survey of different approaches [31] depending on their application in the context of wireless networks (energy consumption, resource allocation, power control, etc.). All these methods have in common the definition of a precise goal (for example, equal video quality) that, in our case, by the definition of 3 GPP is not clear. More specifically in the field of WiFi-LBT, [PERSON] et al. [32] proposed using the average throughput per user with a simple division between the scenario with two WiFi operators and the one of WiFi-3 GPP coexistence. However, this approach only considers one metric and does not give a complete idea of how the behavior is modified when both technologies are used. In this sense, [PERSON] et al. [33] proposed the mapping between fairness and first-order stochastic dominance. Under this premise, the precept of fairness is fulfilled much more faithfully under the authors' criteria and can thus be extended to various parameters. It is because of this lack of flexibility that the Jain Fair Index, which is quite widespread for scheduling protocols for example, has proven not to be a good candidate in this case [34]. Taking this into account, the performance indicators chosen for the coexistence evaluation of WiFi and LBT scenario (denoted as W+L) [15] are based on UDP file transfer service model following a Poisson arrival process with a fixed file size (FTP Model I), as explained in [22], to generate background traffic. Therefore, based on comparison given by a scenario with two WiFi operators coexisting (called WiFi-WiFi, W+W), an assessment of fairness based on Experimental CDF comparison using Kolmogorov-Smirnov two-sided tests used as described in [33] follows the procedure in Algorithm 1. Thus, the distribution of WiFi UPI-based performance (i.e., mean latency and throughput) when coexisting with LBT are considered to be similar to the baseline performance distribution given by W+W scenario when P value (probability of a null hypothesis) being true with a certain significance level \(\alpha\) reaches a certain value (i.e., 0.05). Equivalently, its obtained Dmax is at least \(D_{\alpha}\).