SIMPLIFIED CDMA FOR WIRELESS DATA NETWORKS

MULTIPLE ACCESS PROTOCOLS ARE USED TO PERMIT LARGE NUMBERS OF INDEPENDENT TRANSMITTERS TO SHARE A SINGLE COMMUNICATION CHANNEL. THERE ARE THREE DIFFERENT TYPES OF MULTIPLE ACCESS PROTOCOLS WHICH ARE USED IN MOST WIRELESS DATA NETWORKS TODAY-TDMA, CDMA AND ALOHA. CDMA PROTOCOLS CAN BE EFFICIENT BUT AS THEY ARE IMPLEMENTED TODAY, THEY TEND TO BE EXTREMELY COMPLICATED BECAUSE OF THE USE OF MULTIPLE CODES TO SEPARATE RADIO TRANSMISSIONS FROM DIFFERENT USERS. RESEARCHERS ARE DEVELOPING THE TECHNOLOGY OF A NEW KIND OF CDMA WHICH REQUIRES ONLY ONE COMMON CODE FOR ALL USERS IN THE NETWORK. THIS NEW MULTIPLE ACCESS PROTOCOL USES AN ALOHA MECHANISM TO SEPARATE TRANSMISSIONS FROM DIFFERENT USERS IN THE SYSTEM. THE PROTOCOL IS CALLED SPREAD ALOHA CDMA. THE USE OF A COMMON CODE FOR ALL TRANSMITTERS IN A SPREAD ALOHA CDMA NETWORK SIMPLIFIES THE IMPLEMENTATION OF CDMA WHILE INCREASING THE OVERALL EFFICIENCY OF THE MULTIPLE ACCESS PROTOCOL.