# In Situ Assessment of Uplink Duty Cycles for 4G and 5G Wireless Communications
## 2 Materials and Methods
For 4G, values were randomly picked from those reported (from the chipset) in the observation period and then averaged. Thus, for 4G, the observation period was random and depended on the parameters considered: for the uplink power (i.e., PUSCH Tx power), the averaged observation period was 200 ms, whereas this was 400 ms for the transport block size (i.e., PUSCH TBS). For 5G, the observation period was 500 ms.  
As there was no direct parameter reported relating to the number of transport blocks (TBs) for 5G NR (see Table 3), we opted to use an indirect way to calculate this parameter for both 4G LTE and 5G NR. Since the throughput is equal to the number of TBs times the size of those transport blocks, and both the throughput and transport block size (TBS) were recorded using QualiPoc (Table 4), we used the following equation:  
\[\text{Average number of TBs [/s] = Throughput [MBit/s] \times 10^{6}\ [\text{bit/Mbit}]/TBS [bit].} \tag{1}\] \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter [Unit]** & **Technology** & **Name** & **Description** \\ \hline \multirow{6}{*}{**Transmit Power** [dBm]**} & 5G NR & PUSCH Tx power & \begin{tabular}{c} Physical Uplink Shared \\ Channel (PUSCH) transmit \\ (Tx) power of the 5G NR cell. \\ Current (total) transmitting \\ power (on the PUSCH). \\ Current transmitting power on \\ the Physical Uplink Control \\ Channel (PUSCH). \\ \end{tabular} \\ \hline \multirow{6}{*}{**Number of Transport** **Blocks [-]**} & 5G NR & n/a & n/a \\  & 4G LTE & PUSCH number of TBs & \begin{tabular}{c} Number of transport blocks \\ (TBs) allocated to the UE in a primary cell. \\ \end{tabular} \\ \hline \multirow{6}{*}{**Throughput [kbps]**} & 5G NR & \begin{tabular}{c} Scheduled \\ PUSCH Thp \\ \end{tabular} & \begin{tabular}{c} Resulting PUSCH throughput \\ (Tbp) of all transmitted TBs, \\ including non-acknowledged \\ TBs. [12] \\ Throughput \\ \end{tabular} \\  & 4G LTE & PUSCH throughput & \begin{tabular}{c} Throughput on the PUSCH of \\ the primary cell, only counting \\ the transport blocks that are \\ sent for the first time. \\ \end{tabular} \\ \hline \multirow{6}{*}{**Transport Block** **Size [bit]**} & 5G NR & Avg PUSCH TBS & \begin{tabular}{c} Average PUSCH transport \\ block size (TBS) in the \\ observation period. \\ Average transport block size: \\ average number of user data \\ bits transmitted in the TTIs \\ associated with the UE. \\ \end{tabular} \\ \hline \multirow{6}{*}{**Number of Resource** **Blocks [-]**} & 5G NR & PUSCH RB average & \begin{tabular}{c} Average number of PUSCH \\ RB used in the \\ observation period. \\ \end{tabular} \\  & 4G LTE & \
\begin{tabular}{c} Channel quality UL \\ re-source block \\ number 2 \\ \end{tabular} &
\begin{tabular}{c} Uplink resource block \\ (RB) number. \\ \end{tabular} \\ \hline \hline \end{tabular}  
* Parameters ‘Tx power’ and ‘PUSCH Tx power’ were equal for 4G LTE. 2 Equal to the parameter ‘4G LTE PUSCH RB average’, but with more samples.  
\end{table} 
Table 3: Non-exhaustive list of parameters provided by the Rohde & Schwarz QualiPoc Android Ver. 21.03 SP 2 [11] tool. Moreover, as the number of TBs per transmission time interval (TTI) is either 0 or 1 (in the case of no spatial multiplexing)--in other words, there is either a transmission or no transmission--the ratio of the average number of TBs and the number of TTIs per observation period can be considered the duty cycle (DC) (i.e., the ratio of TB transmissions to elapsed TTIs):  
\[\text{DC [-]}=\text{Average number of TBs [/s]/(\#\text{TTI/s}),} \tag{2}\]  
with the number of TTIs per second (\(\#\text{TTI/s}\)). For 4G, the TTI is fixed at 1 ms, resulting in a maximum number of 1000 TTIs per second. For 5G, the TTI depends on the SCS (sub-carrier spacing) of the 5G signal, with values between 1 ms (for an SCS of 15 kHz) and 62.5 us (for an SCS of 240 kHz) corresponding to a maximum number of TBs per second between, respectively, 1000 and 16,000. Based on the configuration of the SCS, which was 30 kHz during our in situ tests, a TTI of 500 ms was expected.