http://help.sap.com/saphelp_nw70/helpdata/EN/cf/21f232446011d189700000e8322d00/content.htm
Hi,
1. You can request your basis team to increase the session time
2. Try using SE14 instead of SE11.
Choose the option for "Processing Type" as Background and then activate the table.
3. There is another option mentioned in the link , you can check that.
Thanks
Deepak