For example, an Access Point (AP) may be configured to set a user specific field in a Signal (SIG) field. For example, the user specific field may be configured for a user of a plurality of users in a Multi-User (MU) Multiple-Input-Multiple-Output (MIMO) (MU-MIMO) allocation. For example, the user specific field for the user may include an Unequal Modulation and Coding Scheme (MCS) (UEM) information subfield configured to indicate an assignment of a plurality of MCSs for the user. For example, the user specific field for the user may include a spatial configuration subfield configured to indicate a number of spatial streams for the user and a total number of spatial streams in the MU-MIMO allocation. For example, the AP may be configured to transmit a Physical layer (PHY) Protocol Data Unit (PPDU) including the SIG field.