#### ammaralwazzan

##### Newbie level 6

hi everybody

i have a bad problem with my code ....

First of all i write a matlab code for OFDM-CDMA system. the following picture shows the structure of the system :

but unfortunally the results for BER not stable .

for doppler frequency = 0.0001

for doppler frequency = 3Hz

notes:

1) i use the built in matlab function rayleighchan for implement the effect of Rayleigh channel.

2) i choose the uplink case (as the system structure showed)

3) i generate a OFDM-CDMA signal for each user then each signal enter alone [/COLOR]to rayleighchan then i add the all signals together then adding AWGN and finally enter to receiver.

4) i calculate the BER for user number one only

5) i make iteration for the code ,, and i reach to 500 times without reach to stable result

6) for checking i run the code without any channel (nor rayleigh nor AWGN) i get 0 errors.

7) i use an itu recommendation for parameter of rayleigh channel which is channel A for indoor to outdoor case

(you can type in matlab help for this channel simply it is 4 path channel with delay equal to (0 110 190 410)nSec and path gain equal to (0 -10 -20 -23) dB)

Any help will be appreciated

thank you to everyone read, comment or help in this problem

i have a bad problem with my code ....

First of all i write a matlab code for OFDM-CDMA system. the following picture shows the structure of the system :

but unfortunally the results for BER not stable .

for doppler frequency = 0.0001

for doppler frequency = 3Hz

notes:

1) i use the built in matlab function rayleighchan for implement the effect of Rayleigh channel.

2) i choose the uplink case (as the system structure showed)

3) i generate a OFDM-CDMA signal for each user then each signal enter alone [/COLOR]to rayleighchan then i add the all signals together then adding AWGN and finally enter to receiver.

4) i calculate the BER for user number one only

5) i make iteration for the code ,, and i reach to 500 times without reach to stable result

6) for checking i run the code without any channel (nor rayleigh nor AWGN) i get 0 errors.

7) i use an itu recommendation for parameter of rayleigh channel which is channel A for indoor to outdoor case

(you can type in matlab help for this channel simply it is 4 path channel with delay equal to (0 110 190 410)nSec and path gain equal to (0 -10 -20 -23) dB)

Any help will be appreciated

thank you to everyone read, comment or help in this problem