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3G MIMO describes MIMO techniques which have been considered as 3G standard techniques.
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MIMO, as the state of the art of intelligent antenna (IA), improves the performance of radio systems by embedding electronics intelligence into the spatial processing unit. Spatial processing includes spatial precoding at the transmitter and spatial postcoding at the receiver, which are dual each other from information signal processing theoretic point of view. Intelligent antenna is technology which represents smart antenna, multiple antenna (MIMO), self-tracking directional antenna, cooperative virtual antenna and so on.
Spatial precoding of intelligent antenna includes spatial beamforming and spatial coding. In wireless communications, spatial precoding has been developing for high reliability, high rate and lower interference as shown in the following table.
The table summarizes the history of 3G MIMO techniques candidated for 3G standards. Although the table additionally contains the future part but the contents are not clearly filled out since the future is not precisely predictable.
Generation | 3G | 3G evolution | Beyond 3G | Future |
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Deployment | 2003/4 | 2005~6/2007~8/2009~10 | 2012~2015 | 2015~2020 |
Standard | WCDMA | HSPA/HSPA+/LTE | IMT-Advanced | Beyond IMT-Adv |
Total rate | 384kbit/s | 14/42/65~250Mbit/s | 1Gbit/s | >10Gbit/s |
Bandwidth | 5 MHz | 5 MHz/20 MHz | 20~100 MHz | >100 MHz |
Requirement Paradigm | High reliability (High quality) | High rate (High capacity) | Lower interference | High intelligence |
Method | Spatial diversity | Spatial multiplexing | Spatial cancellation | Ambient intelligence |
Spatial coding (SC) | Spatial diversity coding | Spatial multiplexing coding | Spatial cancellation coding | Ambient intelligence coding |
Spatial beamforming (SB) | Single-stream beamforming | Multi-stream beamforming | Interference nulling beamforming | Ambient intelligence beamforming |
Examples | SC: Alamouti coding, SB: TxAA | SC: BLAST coding, SB: SVD | SC: DPC, SB: MU-BF | Such as cooperative MIMO |
IA technology enables client terminals, which have either multiple antennas or a self-tracking directional antenna, to communicate to each other with as high as possible signal-to-interference-and-noise ratio (SINR). Assume that there is a source terminal, a destination terminal, and some candidate interference terminals. Compared to conventional approaches, an advanced IA based terminal will perform spatial precoding (spatial beamforming and/or spatial coding) not only to enhance the signal power at the destination terminal but also to diminish the interfering power at interference terminals. As a human does, the advanced IA terminal is given to know that occurring high interference to other terminals will eventually degrade the performance of the associated wireless network.
The following items list the issues of the multiple antenna research aims to improve the performance of radio communications.
Here are the definition of principal keywords to clarify the objective and the operations of intelligent antenna.
Terminology | Definition |
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Intelligent antenna | Antenna technology that uses some sort of electronic intelligence to enhance wireless system performance. Electronic intelligence is implemented by spatial pre/post-coding techniques such as spatial information coding and spatial signal beamforming. Smart antenna has been more widely used to represent the similar meaning. |
Smart antenna | In the narrow sense, antenna technology that employs array antennas with beamforming techniques to enhance wireless system performance. In the wide sense, equivalent terminology to intelligent antenna. |
MIMO | Wide sense and well-known: MIMO is the state of the art of IA and SA.
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The following items list the web sites related to the multiple antenna research.
Types | Antenna configuration | Basic solution | Advanced solution |
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Diversity | d > wavelength | Rx: MRC, MMSE, etc., Tx: STTD, CLTD | BLAST (spatial multiplexing) |
Phased Array | d < wavelength | Switched beams | Steered beams |
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