Techniques to improve receiver sensitivity

1. A smaller bandwidth could be used. This is usually fixed by IF requirements.
2. The loss in the preselect filter or switch could be reduced. For example,
the LNA could be placed in front of one or both of these components.
3. The noise figure of the LNA could be improved.
4. The LNA gain could be increased reducing the effect of the mixer on
the system NF.
5. A lower NF in the mixer would also improve the system NF.
6. If a lower SNR for the required BER could be tolerated, then this
would also help.