Question: What is the primary function of a sidelink physical channel in E-UTRA?
Option 1: To carry control information between eNodeBs
Option 2: To serve as an interface between higher layers and the physical layer for sidelink communication
Option 3: To multiplex multiple sidelink channels onto a single resource block
Option 4: To provide feedback from the receiver to the transmitter
Explanation: A sidelink physical channel is defined as an interface between higher layers and the physical layer for sidelink communication, carrying information originating from higher layers. This is evident in the context of E-UTRA, where sidelink channels are used for device-to-device communication.