96 Antennas System For The Next Generation Of Wireless
The “Rice rig”, also known as “Argos”, represents the biggest system build to perform massive MIMO. Recall that MIMO (Multiple-Input Multiple-Output) is a technique in wireless systems that allows sending data more efficiently since several antennas work together in order to take advantage from multipath. This phenomena causes interference between the signals. In order to see a more technical description about MIMO, have a look at this post: https://communities.theiet.org/blogs/426/431#.UwE3ePl5NC8
MIMO is used in 4G LTE and in the last version of Wi-Fi, 802.11ac, but it implies using a small number of transmitters and receivers. Massive MIMO increases this capability by using hundreds of antennas. In a previous version of Argos, with 64 antennas, they showed that the capacity of the network increased ten times: and this means, giving service to a higher number of users.
Massive MIMO requires more processing power because the base stations send the radio signals with a more focused beam to users. The main Argos’ goal is testing the real benefits of using this technique: how scalable is MIMO? How many antennas can be used?
One alternative or complement is 5G and the use of higher frequencies, around 28 GHz. The wavelengths at these frequencies are around two orders of magnitude smaller than the ones used today for wireless communications, which allows placing more antennas in the same space. However, signals at 28 GHz are easily blocked by buildings, vegetation and rain. That’s the reason why they were not used before.
However, Samsung and the University of New York worked together to get a matrix of 64 antennas which sends the same signal from all of them, by splitting it, and dynamically changing the active antennas and the direction where the signal is sent to avoid blockage.
4G LTE can offer 75 Mbps, although in practical terms it offers a bit less. Those two developments will allow 5G offering higher data rates, smaller transmitter, new protocols and new network designs.
During the last years, the demand for mobile communication systems has spectacularly increased: at present, there are 6,800 million of mobile devices for a population of 7,000 people million in the world, and it is expected that, by 2014, there will be 7,300 million, according to the ITU. That is the reason why these systems have evolved, developing new technologies more efficient each time. The latest standard in mobile communication systems, Long Term Evolution (LTE) shows this evolution. It incorporates highly efficient techniques such as OFDM (Orthogonal Frequency Division Multiplexing) and other techniques like MIMO (Multiple-Input Multiple-Output). In the next post, we will see the characteristics of the physical layer of LTE, mainly OFDM, in order to justify why its use is strikingly increasing in mobile communications.
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