World as we all know is growing smarter by the day. We see smart phones, 3G, 4G, WLANs becoming integral part of our lives. At the crux of all progress lies the fact that we desperately seek high data rates. We can't wait any longer than few seconds for a video to be flashed across our screens. To add to this ever increasing thirst for speed, humans also seek quality. We migrated from gramophones to tapes to optical disks to digital signal processors for high fidelity. Quality comes only with higher volume of data. Bitter but true! Compare a real media filesize and its quality with mp3 or mp4 filesize and its quality.
A MIMO or a Multiple Input Multiple Output system is a clever solution to achieve high data rates. It is a technique which combines tweaking with antennas and DSP to get blazing speeds. We all know that when a signal is fed to antenna, it takes several paths before it reaches a receiver. Also if one manages to keep several receivers-spaced few wavelengths apart- in the vicinity of a transmitter, they all receive and receive signals of different magnitudes and phases which is primarily attributed to multipath propagation of signals before reaching each receiver.
MIMO cashes on this thing-multipath effect. A data stream to be transmitted is scrambled, encoded and interleaved only to be split into several parallel data streams. These parallel data streams are fed to equal number of transmitters. Effectively, what the design has achieved is that data has been divided into chunks with each chunk been thrown to the receiver with a separate transmitter.
Remember that each of the transmitter throws data to the receiver, with the receiver getting it from multiple paths. Here lies the key to MIMO. If one has a fixed spatial receiver and transmitter configuration, the receiver always gets a uniquely weighed combination of the transmitted signals. In other words, each receiver receives a unique pattern from all the transmitters-the pattern being decided by the paths taken by the signals coming in. If one employs more that just a single receiver, all of them receive all the transmitted signals but each of the receiver gets a uniquely weighed version of the parallel data streams.
With the help of Digital Signal Processing Algorithms, it is possible to analyze and extract all the transmitted parallel data streams. These data streams are descrambled and decoded to get back the original transmitted message. Below figure illustrates the operation of MIMO configuration.
This is how MIMO quenches thirst for high data rates.Transmitting two or more data streams in the same bandwidth multiplies the data rate by the number of streams used.
A MIMO or a Multiple Input Multiple Output system is a clever solution to achieve high data rates. It is a technique which combines tweaking with antennas and DSP to get blazing speeds. We all know that when a signal is fed to antenna, it takes several paths before it reaches a receiver. Also if one manages to keep several receivers-spaced few wavelengths apart- in the vicinity of a transmitter, they all receive and receive signals of different magnitudes and phases which is primarily attributed to multipath propagation of signals before reaching each receiver.
MIMO cashes on this thing-multipath effect. A data stream to be transmitted is scrambled, encoded and interleaved only to be split into several parallel data streams. These parallel data streams are fed to equal number of transmitters. Effectively, what the design has achieved is that data has been divided into chunks with each chunk been thrown to the receiver with a separate transmitter.
Remember that each of the transmitter throws data to the receiver, with the receiver getting it from multiple paths. Here lies the key to MIMO. If one has a fixed spatial receiver and transmitter configuration, the receiver always gets a uniquely weighed combination of the transmitted signals. In other words, each receiver receives a unique pattern from all the transmitters-the pattern being decided by the paths taken by the signals coming in. If one employs more that just a single receiver, all of them receive all the transmitted signals but each of the receiver gets a uniquely weighed version of the parallel data streams.
With the help of Digital Signal Processing Algorithms, it is possible to analyze and extract all the transmitted parallel data streams. These data streams are descrambled and decoded to get back the original transmitted message. Below figure illustrates the operation of MIMO configuration.
This is how MIMO quenches thirst for high data rates.Transmitting two or more data streams in the same bandwidth multiplies the data rate by the number of streams used.
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