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wider coverage and good capacity. mmWave (FR2) uses 60, 120 and 240 KHz subcarrier spacing to provide higher throughputs and ultra-low latency. • mmWave has high air interface propagation losses and hence the cell range is smaller. Small cell range has shorter propagation channel delay spreads. To match 2. Frame Structure: 5G NR supports flexible frame configuration and provides a unique feature through which each symbol within a slot can either be used to schedule an uplink packet (UL) or downlink packet (DL) or Flexible (F). A symbol marked as flexible means it can be used for either uplink or downlink as per requirement. As per 3GPP TS (38.213 Table 11.1.1-1), there are 256 slot formats. Out of 256 formats, first 56 are already defined by 3GPP with various combinations of D, U, F. The slot/subframe configuration of mmWave shall be aligned with the other existing TDD systems to avoid interference. The preferred slot configurations are 3:1 and 4:1 (DL: UL). The frame configuration should be defined in the planning tool as per the use case. In our exercise we have chosen below configuration for a DL heavy data use case. this shorter channel delay spread there is need for shorter cyclic prefix and shorter symbol duration which can be achieved using higher SCS like 120 KHz. • mmWave frequencies suffer from greater oscillator phase noise which causes a random jitter in the phase of the received signal. The magnitude of this jitter is relatively small when compared to the magnitude of the high SCS thus higher SCS are more robust against this jitter.
Figure 10: NR Frame configuration
NSA or SA
5G NR supports both NSA and SA deployment mode and let’s understand which strategy is the right fit in different scenario. NSA mode has been mostly preferred in early mmWave deployment with one clear reason that 4G core was readily available and current product ecosystem does not support mmWave SA mode deployment. One should keep in mind the below points while planning a mmWave network:
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