Design of a wireless comms system

[pogojuice]

Hello everyone, this is my first post on the site!

Im new to Matlab but am experimenting with it.

Basically i am designing a digital wireless system that should have security of a high level (against eaves dropping and jamming) I want it to operate over 10km with a 10Ghz frequency and support 100Mbits/s data rate. It should be subject to free-space path loss and thermal noise at the reciever.

I want to include the following features in the design:

Amplitude-phase modulation - not sure which one??
DSSS (for security)
FEC for data integrity.

I am not really too sure how to approach this in terms of blocks to use.

If anyone has any suggestions, it would be most appreciated.

Cheers

pogo

 

[jsolar]

Your last and final touching of modulation should be your physical layer encryption. Do this with a spreading code, preferably a CDMA type phase modulation (see the 3G recommendations, they are very good ideas). At 0.1 Gbps raw data rate, assuming 4X spreading and final 20 dB spread you will have a modulation BW 40 GHz. This won't fit with your 10 GHz carrier. So, you might want to work a different homework problem. Or live with minimal final spreading and limited jamming rejection. For FEC use a combination of inner block codes and outer convolutional codes. Make sure you have a complete security policy. Part of that will include security modulation effects at L2 and L0. Since this is a MATLAB exercise you can modulate the antenna polarization and assume both transmit and receive diversity. This sounds like fun.