Question: In a shared spectrum scenario, as per 3GPP specifications, what happens when a User Equipment (UE) fails to access the channel(s) before an intended Uplink (UL) transmission to a gNodeB (gNB), specifically in cases where `semiStaticChannelAccessConfigUE` is present?
Option 1: The UE automatically switches to another available channel for the UL transmission.
Option 2: Layer 1 notifies higher layers about the channel access failure, initiating potential fallback or retry procedures.
Option 3: The gNB allocates a new channel for the UE's UL transmission within the same frame structure.
Option 4: The UE's intended UL transmission is immediately cancelled without further notification.
Explanation: In shared spectrum scenarios, managing channel access efficiently is crucial. When a UE fails to access a channel before an intended UL transmission, and given that `semiStaticChannelAccessConfigUE` is present (indicating specific semi-static channel access configurations for the UE), the immediate action at the physical layer (Layer 1) is to notify higher layers of this failure. This notification allows for adaptive responses such as adjusting transmission parameters, retrying on a different channel, or employing other fallback strategies, highlighting the importance of inter-layer communication in dynamic spectrum environments.