Hybrid Multiple Access Schemes The simultaneous transmission of multiple data streams over the same medium can be achieved with different multiplexing schemes. Most communications systems, such as GSM, DECT, IEEE 802.11a, and HIPERLAN/2, use multiplexing based on either time division, frequency division or a combination of both. Space division multiplexing is applied to further increase the user capacity of the system. The simplest scheme of space division multiplexing is antenna sectorization a