Range Enhancement in Radio Communication

[carpediem.td]

Hi friends,
I need some papers on the techniques for increasing the range in radio communication(long range). The constraint my professor has put is that I can't change power levels and the antennas. Rather, I need to focus on techniques to increase the range related to the follwing:

1. NBDS(Narrowband Direct Sequence) Spread Spectrum.
2.Channel Estimation techniques
3.Rake Receivers

Please give me some pointers and suggest some journal papers that deal with range enhancement.

 

[carpediem.td]

Please somebody reply...

Thanks..

 

[jallem]

To increase the range without changing the transmit power level or
the antenna characteristics, you should see what affect the
link budget. What is left to you to change is:
a) decrease the sensitivity of the receiver,
b) decrease de losses in the transmission and the
receiving site
c) change the channel,
d) lower the speed of transmission if digital.