MIMO
 

Multiple-Input-Multiple-Output (MIMO) is a cutting edge antenna technology transmitting multiple data streams on multiple transmitters to multiple receivers. Multiple antennas are used at both the transmitter and the receiver to increase the odds of receiving the signal, especially when the link has Non-Line-of-Sight (nLoS). MIMO offer tremendous performance gains for wireless devices at a relatively low cost. The underlying technology of Proxim’s backhaul products Tsunami® QB-8100, MP-8100 Series and Proxim’s Access Points ORiNOCO® AP-8100 radios are based on a combination of MIMO and OFDM technologies. High performance OFDM-MIMO combination enhances robustness using multiple transmitters and receivers, allowing the radios to completely take advantage of this antenna technology.

In real-world environments, signals reflect from various objects to reach the receiving antenna, hence a signal follows different distances before being received. This phenomenon is called Multipath propagation and causes interference and fading in non-MIMO radios. On the receiver side, having multiple receivers increases the amount of received power and also reduces multipath problems by combining the received signals for each frequency component separately. Hence, MIMO significantly improves the overall gain.

Non Line-of-Sight Connectivity – 3x3 MIMO
 
Proxim’s MIMO features:
  • Proxim’s backhaul products Tsunami® QB-8200 & MP-8200 Series products feature top of the range 3x3 MIMO capabilities with spatial multiplexing
  • Proxim’s Access Points ORiNOCO® AP-8100 are 802.11n products featuring 3x3 MIMO with spatial multiplexing
  • Significant hike in throughput and range with no increase in transmit power or channel bandwidth
  • MIMO-OFDM combination radios solve interference, fading and multipath problems
  • Higher spectral efficiency and robust signal quality results in significant increase in overall gain
  • Incredible performance gains at lower costs

 

MIMO also uses Spatial multiplexing transmission technique to transmit independent and separately encoded data signals from each of the multiple transmit antennas while reusing or multiplexing in the space dimension. These independent data signals are called Spatial streams. The transmitting antenna uses multiple radio Tx chains and signal paths to simultaneously transmit different data streams, whereas the receiver combines the Rx signals resulting in higher throughput.

MIMO spatial multiplexing transmission technique

By increasing the number of receive and transmit antennas, the throughput of the channel increases linearly resulting in high spectral efficiency. MIMO technology has become one of the most important wireless techniques to be employed in recent years especially as the spectrum is becoming a more valuable commodity than ever for wireless communications. MIMO radio technology being integrated into many new technology standards like LTE, WiMax, Wi-Fi and many other wireless technologies to provide improved spectral efficiency along with increased link capacity and reliability.

Wi-Fi networks are often plagued with inadequate range and spotty coverage resulting in performance fluctuations. Stable bandwidth is vital for latency sensitive real time applications such as video streaming, online gaming, VoIP, web surfing, etc. Proxim’s top-of-the-line ORiNOCO® Wi-Fi Access Points AP-8100 feature the 802.11n Wi-Fi standard delivering up to 320Mbps real throughput with 3x3 MIMO and spatial multiplexing to offer next generation internet experience today. Only a couple of backhaul products feature 2x2 MIMO in the marketplace, Proxim’s Tsunami® QB-8200 and MP-8200 Series go a step further to use sophisticated 3x3 MIMO to increase signal robustness and range.

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Glossary of Wireless Terms