s grows, the spec- tral efficiency can increase due to the multiuser diversity. Temporal multiuser diversity can be taken advantage of by selectively allocating band- width in the time domain. This is done by scheduling the user with highest channel quality the entire channel bandwidth at any point in time. This type of multiuser diversity gain was demonstrated by Bhagwat et al., who achieves a 15% performance improvement by applying approach physical layer. This scenario is different from the one a 4G/5G OFDMA scheduler is faced with, as the MAC layer in the presented paper is not aware of any prefer- ential transmissions. Smith et al.'s approach is a popular one, with other authors such as Fragouli et al. using it as the basis for their own slightly improved algorithm. Andrews et al. also describe that the quality of a wireless channel is typically different for each user and changes randomly in time, both on slow and fast timescales. 8 The algorithm in this paper takes advantage of channel variations by giving some form of priority to users with temporarily better channels. Another paper where temporal multiuser diversity is taken advantage of is Ref.9 where an algorithm for opportunistic transmission scheduling yields 20%-150% performance improvements over those which do not consider this. Viswanath et al. even suggest using multiple antennas to create artificial variations in channel quality over time, in order to better exploit them. 10 The exploitation of temporal multiuser diversity is investigated by Knopp and Humblet whose results suggest that in order to attain highest capacity, only one user should transmit at any given time over the entire bandwidth. Eryilmaz et al. present a particularly interesting approach to taking advantage of temporal multiuser diversity. 12 Their scheme attempts to do so without any explicit channel quality 244 Open Radio Access Network (O-RAN) Systems Architecture and Design information, relying instead on traffic flow statistics. Considering that channel quality infor- matio