Multiple antenna configurations can be used to overcome the
detrimental effects of signal multipath and fading when trying
to achieve high data throughput in limited-bandwidth channels.
Multiple-input, multiple-output (MIMO) antenna systems are used
in modern wireless standards, including in IEEE 802.11n, 3GPP
LTE, and mobile WiMAX systems. The technique supports enhanced
data throughput even under conditions of interference, signal
fading, and multipath. The demand for higher data rates over
longer distances has been one of the primary motivations behind
the development of MIMOorthogonal- frequency-division-
multiplexing (OFDM) communications systems. For years, engineers
assumed that the theoretical channel capacity limits were
defined by the Shannon- Hartley theorem1 illustrated in Eq. 1.
Capacity = BW log2(1 + SNR) (1) As Eq. 1 shows, an increase in a
channel's SNR results in marginal gains in channel throughput.
As a result, the traditional way to achieve higher data rates is
by increasing the signal band