Spatial Division Multiple Access (SDMA) & Third Generation Wireless (3G) | Future Enhancements

Some of the key future enhancements to wireless technology include spatial division multiple access (SDMA) and the introduction of third generation (3G) wireless technologies.

Spatial Division Multiple Access (SDMA)

Spatial division multiple access (SDMA) is a system access technology that allows a single transmitter location to provide multiple communication channels by dividing the radio coverage into focused radio beams that reuse the same frequency. To allow multiple accesses, each mobile radio is assigned to a focused radio beam. These radio beams may dynamically change with the location of the mobile radio. SDMA technology has been successfully used in satellite communications for several years.

Figure 1 shows a SDMA system. This diagram shows a single tower that is serving 3 different users from the same radio tower on the same frequency using independent beams of radio energy.

Figure 1: Spatial Division Multiple Access (SDMA)

Third Generation Wireless (3G)

Third generation wireless (3G) is a term commonly used to describe the third generation of technology used in a specific application or industry. In cellular telecommunications, third generation systems used wideband digital radio technology as compared to 2nd generation narrowband digital radio. For third generation cordless telephones, products used multiple digital radio channels and new registration processes allowed some 3rd generation cordless phones to roam into other public places.

The 3G system is actually the universal mobile telecommunications System (UMTS). The UMTS system offers personal telecommunications services that use the combination of wireless and fixed systems to provide seamless telecommunications services to its users. The UMTS allows bandwidth on-demand transmission capacities of up to 2 Mb/s in some of its radiolocations. It should be compatible with GSM and broadband ISDN systems.

Figure 2 shows a 3rd generation broadband wireless system. This system uses two 5 MHz wide radio channels to provide for simultaneous (duplex) transmission between the end-user and other telecommunication networks. There are different channels used for end- user to the system (called the “uplink”) and from the system to the end-user (called the “downlink”). This diagram shows that 3G networks interconnect with the public switched telephone network and the Internet. While the radio channel is divided into separate codes, different protocols are used on the radio channels to give high priority for voice information and high-integrity to the transmission of data information.

Figure 2: 3rd Generation Wireless