# Empirical Study on 5G NR Cochannel Coexistence
## 5 5G Performance for Industrial Control
### Unsynchronized TDD Pattern  
As described in Section 5.1, the indoor network performance, with interference for the three different scenarios with a synchronized TDD pattern, is quite similar for median values and, with only a few milliseconds of a latency increase, has been observed for certain high percentiles. However, the TDD pattern DDDDU is DL oriented and might not be suitable for the application requirements of the indoor network. There are TDD patterns currently available in our test network with a downlink-uplink balance more suitable for the requirements of the new industry automation applications. However, it is still uncertain how the cross-link interference for a mid-band TDD spectrum could affect the indoor network performance in a real network deployment. In this article, we analyzed the impact of different TDD patterns for the indoor and outdoor network. In particular, the two TDD patterns studied, DDDU (75% DL-25% UL) and DDDDUDDDUU (70% DL-30% UL), are more UL oriented than the current harmonized DDDDU (80% DL-20% UL) pattern. For the unsynchronized TDD patterns, the coexistence of DL slots is different compared to the synchronized case. The DL slots of DDDU will collide arbitrarily 80% of the time with the outdoor DL (near-far interference) slots of DDDDU, while the remaining 20% of the time indoor DL slots will collide with outdoor UL slots (cross-link interference). As can be observed in the graph of Figure 5a, the DL latency increase compared to baseline for UL interference is above 300 ms. Due to the interference on this 20% of the indoor DL slots, the 5G system is not capable of handling the targeted medium load traffic. Instead, for the DL interference, the impact is similar, as seen in Section 5.1 with a slightly better performance due to less DL near-far interference. For the other unsynchronized TDD  
Figure 4: Increase in DL (**a**) and UL (**b**) latency compared to their baselines for synchronized TDD pattern of DDDDU with different indoor/outdoor UE deployment locations. pattern (DDDDUDDDUU), the indoor DL slots only collide with outdoor DL transmissions, as for the synchronized TDD pattern. Then, no cross-link interference is expected and, as can be observed in the graph of Figure 5b, no impact is coming from the UL interference. Nevertheless, with DL interference, the latency increase is higher compared to the other values on the Figure 5a. The interference constellation for the indoor UL slots and unsynchronized TDD pattern is also different compared to the synchronized TDD pattern. For DDDU used indoors and DDDDDU used outdoors, the near-far interference and cross-link interference for indoor UL slots are 20% and 80%, respectively. In Figure 6a, it can be observed that the near-far interference (UL interference) has a longer latency increase compared to baseline than the cross-link interference (DL interference) for high percentiles. For the 99 th and 99.9 th percentile, the difference is of around 1 ms and 2 ms, respectively. For DDDDDUDDDUU, the near-far interference is 67%, while cross-link interference is 33% of the indoor UL slots. From the graph of Figure 6b, the results of cross-link interference (DL interference) are slightly better compared to the results on the Figure 6a and the impact of near-far interference (UL interference) is similar, despite having more probability of such interference. We break down the indoor DL and UL network performance to analyze the impact for different indoor-outdoor UE locations. In Figure 7, it can be observed that, as we increase  
Figure 5: Increase in DL latency compared to its baseline for unsynchronized TDD pattern. (**a**) Indoor TDD pattern DDDU and outdoors DDDDDU are configured. (**b**) Indoor TDD pattern DDDDDUDUU and outdoors DDDDDU are configured. Figure 6: Increase in UL latency compared to its baseline for unsynchronized TDD pattern. (**a**) Indoor TDD pattern DDDDU while outdoors DDDDDU are configured. (**b**) Indoor TDD pattern DDDDDUDUDUU and outdoor DDDDU are configured.