Failed At Syntax Check of Nested Tables

Hi

I got syntax check exception for this table DDL:

CREATE TABLE my_table (
objs SMS_DATA
)
NESTED TABLE OBJS.MOBILES STORE AS nested_table;

it says there is an error in "." character at "OBJS.MOBILES".

Here is declaration of my used type:

CREATE OR REPLACE TYPE MOBILE_V AS TABLE OF varchar2(20);

CREATE OR REPLACE TYPE SMS_DATA AS object (TEXT varchar2(1000),DATE_GENERATE DATE,TYPES varchar2(25),MOBILES MOBILE_V);

Thanks for your help.