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Mimo + OFDM

Amimon's Video Modem solution utilizes both MIMO and OFDM technologies to allow for the magic of Joint Source Channel Coding (JSCC) capability to transmit full uncompressed 1080p60 HD video resolution over a bandwidth of 40MHz. The multiple-input and multiple-output, or MIMO, is the term used for multiple antennas at both the transmitter and receiver to improve communication performance.


MIMO technology offers a significant increase in data throughput and link range without additional bandwidth or increased transmit power. It achieves this by spreading the same total transmit power over the antennas to achieve an array gain that improves the spectral efficiency (more bits per second per hertz of bandwidth) or to achieve a diversity gain that improves the link reliability (reduced fading). Because of these properties, MIMO is an important part of modern wireless communication standards, such as IEEE 802.11n (Wifi), 4G, 3GPP Long Term Evolution, WiMAX, HSPA+ and – WHDI.

 

Since spatial multiplexing techniques makes the receivers very complex, MIMO is typically combined with Orthogonal Frequency-Division Multiplexing, or OFDM modulation, where the problems created by multi-path channel are efficiently handled. WHDI standard incorporates MIMO-OFDM (in comparison, the IEEE 802.16e standard incorporates MIMO-OFDMA; and the IEEE 802.11n standard recommends MIMO-OFDM).
Amimon's MIMO implementation allows for 4x5 or 2x5 MIMO channel model.


This means the transmitter sends multiple streams (two or four) by multiple transmit antennas. The transmit streams go through a matrix channel which consists of all possible paths (see diagram below) between the transmit antennas at the transmitter and the receive antennas at the receiver. Then, the receiver gets the received signal vectors by the five receiving antennas and decodes the received signal vectors into the original information.

 

The use of five receiving antennas allows the receiver to choose the "best" four out of five received signals for solving the channel's matrix.