Not knowing what you are tyring to do exactly, I would be remiss to not point out that you can make a receiver that does not have a mixer at the front of it! Then you would not need an LO.
If you pulse amplitude modulate the transmit signal (OOK modulation), then the receiver only has to figure out the on/off transmit energy. You can use a bandpass filter at the receiver input, and some sort of analog RF detector. IF there is not too much interference at the same frequency, an Bandpass filter, LNA, and a log detector would work fairly well out to maybe 15 meters.