Solution : https://service.sap.com/sap/support/notes/161292 (SAP Service marketplace login required)
Key words :
reporting userthe reporting user executes queries, tools -> administration -> user maintenance -> activity groups, additional key words authorization, create user-defined templates, choose 'edit -> insert authorizations ->, bw user roles start, bw user tasks start, sap business information warehouse, activity group maintenance refer, underlying user tasks