Iphone 4s not picking up wifi

Hi

Really strange issue. My iPhone 4s seems to have stopped picking up my home wifi router. I was using wifi at work today so that was fine. I was using wifi at home and it was fine. Now all of a sudden wifi router is not being picked up. I have checked the wifi router it is fine. As my MBA is picking it up fine and is connected.

I have done a soft reboot (holding power button and home button together) no result in getting wifi router back on my iPhone 4s. Any other suggestion guys?

Thanks in advance

Abz