iPhone 4 (iOS6) and problem with texts

Hi,

I'm still using my iPhone 4 on iOS6. The phone is slow but I can cope with it.

There is only 1 thing that really bugs me. When I'm typing (generally a text or an email) and the signal bar changes from let's say 3 bars, to zero bars, then quickly back on to 2/3 bars, the phone doesn't respond to my key strokes. We are talking about 1 second, possibly 1.5 seconds, but it's an annoying second because it happens quite often and it results in half word missed.

The phone has been doing this for quite some time, but only now I decided to ask on the forum to understand a. what is causing this issue and b. how I can fix it (if it's possible to fix it at all!).

The network coverage is so and so, not great, but never had this problem with my old phones.

Apart from this the phone works fine and never had any problems.

Thanks for your help

 

Thanks both.

I still have plenty of space (around 8GB, 32GB model).

I read that iOS7 kills my old iPhone 4 performance wise, I'm not sure I want to upgrade to iOS7...?