复接入，B/W双用户使用直接扩频序列
％ >>>multiple access b/w 2 users using DS CDMA
％ >>>format is : cdmamodem(user1,user2,snr_in_dbs)
％ >>>user1 and user2 are vectors and they should be of equal length
％ >>>e.g. user1=[1 0 1 0 1 0 1] , user2=[1 1 0 0 0 1 1],snr_in_dbs=-50
％ >>>or snr_in_dbs=50 just any number wud do
％ Waqas Mansoor
％ NUST , Pakistan
