ol data unit of 32 bytes (i.e., 20 bytes application data + protocol overhead) within 1 ms in channel quality corresponding to the edge of the coverage (cell-edge conditions) for the Urban Macro-URLLC test environment. Note that target coverage and reliability requirement depend on the deployment scenario and type of operation (e.g., V2X with certain average inter-vehicle speed and distance). In order to verify the compliance, one must run system-level simulations, identical to those for average spectral efficiencies. Using link-level simulations and an appropriate link-to- system mapping for the desired mobility class and the test environment(s), overall statistics for (downlink and/or uplink) SINR values are obtained and the CDF of SINR distribution is calculated for each test environment. Using a new downlink and/or uplink link-level simula- tion, the residual packet error rate within the maximum delay time as a function of SINR is calculated. The satisfaction of reliability requirement is ensured, if the fraction of messages that are correctly delivered within the permissible delay bound is larger than or equal to the required success probability. lviii Introduction and Background Energy Efficiency: Network energy efficiency is the capability of a network to minimize the energy consumption for radio access (and/or core) network operations without affecting the performance of the network. Device energy efficiency (RAN aspects) is the capability of the network to minimize the power consumed by a user device communication subsystem (modem). Network and the device energy efficiencies are related in the sense that they mutu- ally affect efficient data transmission in a loaded network. The energy consumption of a device can be reduced when there is no data transmission to or from the device. Efficient data transmission in a loaded network is demonstrated by the average spectral efficiency. The device energy consumption can be estimated based on the ratio of sleep and wake cycles of the device. The sleep ratio is th