You can't increase the processor speed on iOS devices. If you are having issues with connection related functions I would check your Wifi router to see if you are optimized.
What device do you have? Each year Apple put out new devices with better, faster processors. Perhaps it's time to upgrade? My iPhone 7 Plus is pretty speedy. And as my friend Bam points out WiFi speed can be a factor too, make sure you are getting a fast download speed from your carrier and that your router is working well. They CAN be optimized. Here's some tips from Linksys (a popular router brand) for optmizing youtr router.....