## 4 The Performance Parameters and Application Scenarios of 6G Networks
### Technical Requirements  
When evaluating the capabilities of 6G wireless networks, essential metrics to consider are maximum data transmission speed, the data rate experienced by users, capacity for handling data traffic over a given area, efficiency in terms of spectrum usage and energy consumption, the density of connections within a network, response time, and the support for high-speed user movement. The key performance indicators (KPIs) are illustrated in Figure 4 and further explained below. 1. **Peak data rate:** Aiming for a peak data rate of no less than 1 Tb/s [23] represents a substantial advancement, surpassing the capabilities of 5G by a factor of 100. In specific scenarios like terahertz (THz) wireless backhaul and fronthaul (x-haul), as highlighted in [23], there is an anticipation that the peak data rate could escalate to an impressive 10 Tb/s. 2. **User-experienced data rate:** The 5 th percentile point in the user throughput cumulative distribution function represents the idea of a user-experienced data rate. Simply put, this represents the minimum data rate that a user can expect to receive at any given time or location with a 95% probability. This metric becomes particularly significant when evaluating perceived performance, especially at the periphery of cellular coverage. It serves as an indicator of network quality, influenced by factors like site density, architectural design, and inter-cell optimization. In the context of 5G implementation in highly populated metropolitan areas, 50 Mbps for uplink and 100 Mbps for downlink are the planned user-perceived rates. Considerable progress is anticipated toward 6G's potential, with a tenfold improvement in speed over 5G--1 Gbps or faster--as the target. Moreover, 6G is poised to deliver user-experienced data rates reaching up to 10 Gb/s in specific scenarios, such as indoor hotspots. This advancement signifies a considerable leap in data transfer speeds and holds promise for enhanced connectivity experiences. 3. **Latency:** The time it takes for information to travel, known as latency, varies depending on the application. However, the minimum latency is currently 25 \(\upmu\)s, which is a significant improvement compared to 5G (40 times better). Latency is divided into two types: user plane and control plane latency [25]. The latency of the user plane refers to the time it takes for a packet to be sent from the source in a wireless network to its destination under the assumption that a mobile station is active. The minimum acceptable user plane latency in the context of 5G wireless technology is 4 ms for enhanced mobile broadband (eMBB) and 1 ms for ultra-reliable low latency communications (uRLLC). The objective is to reduce latency to either 100 ms or 10 ms. Control plane latency refers to the duration it takes for a control plane to transition from an energy-efficient state, such as idle, to one where continuous data transmission commences, such as active. In 5G, the control plane has a minimum delay of 10 ms, which is expected to see significant enhancement in 6G. End-to-end (E2E) delay holds greater significance than over-the-air latency, serving as a comprehensive metric in 6G. 4. **Mobility:** The term'mobility' describes the maximum speed a mobile station may reach while meeting the network's acceptable quality of experience (QoE) requirements. The highest speed that 5G can enable for deployment scenarios involving high-speed trains is 500 km/h. However, 6G aims at a maximum speed of 1000 km/h in the context of systems used by commercial airlines [25]. 5. **Connection density:** In the realm of massive machine-type communication (mMTC), this serves as a crucial performance metric for assessment. In 5G, given constraints on  
Figure 4: The 6G key performance indicators. Adopted from [24]. radio resources, the minimum count of devices with a more lenient quality of service (QoS) per square kilometer (km\({}^{2}\)) is presently established at 10\({}^{6}\).