Various embodiments disclosed herein provide for an improved system for selecting and conveying modulation scheme information for an uplink transmission. A network device can determine the channel state information for an uplink transmission based on sounding reference signals received from a user equipment device, and then select a modulation scheme for the uplink transmission based on the channel state information and associated signal to noise ratio. The network device can then send an indication of the selection to the user equipment device using an index number comprising six bits that correspond to an index number in a table of modulation schemes. The table of modulation schemes can include modulation schemes that use transform precoding, as well as modulation schemes that do not use transform precoding.