Dear Prachi,
As Sneha pointed out, assessment under 143 and 148 are mutually exclusive. To answer your query, YES, 148 notice can be issued even if 143 time limit is still available.
Kindly refer to cases mentioned in explanation 2 to section 147 for the same.
"Explanation 2.—For the purposes of this section, the following shall also be deemed to be cases where income chargeable to tax has escaped assessment, namely :—
(a) where no return of income has been furnished by the assessee although his total income or the total income of any other person in respect of which he is assessable under this Act during the previous year exceeded the maximum amount which is not chargeable to income-tax ;
(b) where a return of income has been furnished by the assessee but no assessment has been made and it is noticed by the Assessing Officer that the assessee has understated the income or has claimed excessive loss, deduction, allowance or relief in the return ;"
Now, if you see the above "(b)", it actually provides for situation where reassessment can be done where no assessment has been made. Thus, 148 notice may be issued even before expiry of 147 time limit.
To summarize, there is no need for the AO to go through 143 formalities before issuance of 148 notice provided there is sufficient cause to do the same and the reasons have been recorded by the AO in writing.