How am I supposed to stream music through home sharing if my iPhone turns off the wi-fi everytime the screen locks?

It's really frustrating when I'm trying to stream music to my iPhone using home sharing, & I can't even get through two songs because the screen locks after a minute or so & the wi-fi disconnects. Turning the wi-fi off in this fashion just seems to rule the whole idea of home sharing music on the iPhone, or indeed any device running iOS 6, completely obselete.

I get that it's for saving battery, but I've been reading around in discussions & people have been having this kind of problem with iOS 6 since it's release. Especially people who have bad reception & rely on wi-fi to push through a lot of there messages & emails.

It seems like quite a popular problem, & one that shouldn't be so difficult for Apple to fix. Surely it's not so hard to give the user the option?

Can anyone offer any solutions? I really don't want to have to jailbreak my phone to fix this.

Thanks