Samsung s2 i9100 imei null

Assalam o Alikum. I have samsung s2 i9100. I recently purchase from market last month, but now I did not able to use sim card. When I insert the Sim then no detect sim.
1- No imei show while I check *#06# (also in setting)
2- Unknown Baseband (in setting)

So please help me, solve this issue.