There is one WiFi access points in range of my room and it's mine. Using the WiFi Analyzer application for my Android phone, I've found that the entire channel range is wide open. currently, I'm using Channel 6. Would changing the channel have any impact on signal strength if there's no other WiFi access points around?
It might if there are other devices in the same frequency range (like cordless phones).
There's a couple of devices that also transmit on the same band as wifi.
Check out this wikipedia article for a list.
To quote a page on Cisco.com:
No, it does not matter which channel you are on.
Channels 1 - 11 called the ISM band. They can be used freely.
To improve performance on 2.4ghz
On both 2.4ghz and 5ghz routers you can do the following to improve performance:
Turn on features like frame bursting, or if there are no neighbors that will interfere, turn on channel bonding (sometimes called channel aggregation or 40mhz spectrum).
Things like wireless phones and microwaves which also run on the 2.4 ghz, cover the entire spectrum (all channels).