Grammar for the following language: L = {$a^{k}$$b^{n}$$a^{m}$ : m,n,k $\in$$ N^{+}$ $\land$ m + k $\geq$ n}

I’m trying to create a grammar (having the highest type) for the language:

L = {$ a^{k}$ $ b^{n}$ $ a^{m}$ : m,n,k $ \in$ $ N^{+}$ $ \land$ m +k $ \geq$ n}

I’m not finding any good approach for it. Hints or ideas?

Thanks!