MIMO

Multiple Input Multiple Output (MIMO) is an antenna technology that is used both in transmission and receiver equipment for wireless radio communication. MIMO uses multiple antennas to send multiple parallel signals (from transmitter).

MIMO has been variously defined as "two or more unique radio signals, in the same radio channel, where each signal carries different digital information" and "two or more radio signals which use beam-forming, receive combining, and spatial multiplexing". The capacity of MIMO grows linearly with the number of antennas; for example, 2x2 MIMO doubles the capacity and 4x4 MIMO quadruples capacity.

The use of multiple antennas at both transmitter and receiver allows:

• Substantial increase in peak data rate
• Significantly higher spectrum efficiency, especially in low-interference environments
• Increased system capacity (number of users)

In UMTS systems, operators see a great need for MIMO in "contained environments" such as:

• Hot spots similar to those serviced by today’s WiFi systems (airports, hotel lobbies, etc)
• Academic campuses, in various self-contained areas (quads, auditoriums, cafeterias, etc)
• Stadiums and arenas, again, which offer self-contained environments
• Malls and shopping areas, favored by large numbers of younger, internet-savvy users
• Mass transportation (trains, etc) with users looking for interaction and entertainment
• Enclosed parks and recreation areas
• Residential homes, supplanting DSL/Cable services

Operators believe that, notwithstanding the basic differences in the physical layers used by UMTS and LTE, the benefits envisioned from MIMO in LTE, can also be obtained from MIMO in UMTS systems, starting in Release 7.

MIMO can be used to advance such applications as:

• Streaming Video, Music
• Video Surveillance
• VoIP
• Video Conferencing
• Interactive Gaming
• Mobile TV

Wireless network operators see a need for MIMO (Multiple-Input Multiple-Output) due to its many advantages. Wireless systems using MIMO represent an economical way to increase user capacity, range and throughput in a variety of environments, most notably those which are enclosed and having low radio interference such as small and/or isolated cells.

Additional Resources:

Questions and Answers

EDGE, HSPA, LTE: The Mobile Broadband Advantage (3G Americas White Paper, Sept 2007)

Mobile Broadband: The Global Evolution of UMTS/HSPA – 3GPP Release 7 and Beyond Mobile Broadband: The Global Evolution of UMTS/HSPA – 3GPP Release 7 and Beyond (3G Americas White Paper, Dec 2006)

Member Company Resources:

Alcatel-Lucent

Andrew Corporation

Nortel Networks

Motorola