What is precoding in massive MIMO?
Precoding is the transmitter signal processing needed to affect the received signal’s maximization to specific receivers and antennas while reducing the interference to all other receivers and receiving antennas.
What is hybrid precoding?
Hybrid precoding, a combination of analog and digital precoding, is an attempt to reach a compromise between complexity and performance. By exploiting more than one radio frequency chain, hybrid precoding enables a millimeter wave (mmWave) system to take advantage of both spatial multiplexing and beamforming gain.
Why does MIMO need precoding?
Precoding for Point-to-Point MIMO Systems
Most classic precoding results assume narrowband, slowly fading channels, meaning that the channel for a certain period of time can be described by a single channel matrix which does not change faster. In practice, such channels can be achieved, for example, through OFDM.
What is the difference between beamforming and precoding?
A third answer is that beamforming refers to a single-user transmission with one data stream, such that the transmitted signal consists of one main-lobe and some undesired side-lobes. In contrast, precoding refers to the superposition of multiple beams for spatial multiplexing of several data streams.
What is the use of precoding?
Precoding is a technique that exploits transmit diversity by weighting the information stream, i.e. the transmitter sends the coded information to the receiver to achieve pre-knowledge of the channel. The receiver is a simple detector, such as a matched filter, and does not have to know the channel state information.
What is difference between beamforming and precoding?
What is hybrid beamforming?
Hybrid beamforming combines analog beamforming with digital precoding to intelligently form the patterns transmitted from a large antenna array (Figure 2), and the same technique is used at the receive end to create desired receiver pattern.
What is beamforming in wireless communication?
Beamforming is a technique that focuses a wireless signal towards a specific receiving device, rather than have the signal spread in all directions, like from a broadcast antenna. The resulting direct connection is faster and more reliable than it would be without beamforming.
What is the difference between analog and digital beamforming?
Analog beamforming uses phase-shifters to send the same signal from multiple antennas but with different phases. Digital beamforming designs different signals for each antennas in the digital baseband. Precoding is sometimes said to be equivalent to digital beamforming.
What is the difference between MIMO and beamforming?
MIMO (Multiple Input Multiple Output) antennas operate by breaking high data rate signals into multiple lower data rate signals in Tx mode that are recombined at the receiver. Beamforming arrays are inherently different from MIMO in that the multiple columns of dipoles work together to create a single high gain signal.
What are the types of beamforming?
Beamforming can be divided into two categories depending on the signal bandwidth: narrowband beamforming and wideband beamforming. Narrowband beamforming is achieved by an instantaneous linear combination of the received array signals.
Which technology is used in massive MIMO?
MIMO uses techniques known as spatial diversity and spatial multiplexing to transmit independent and separately encoded data signals, known as “streams”, reusing the same time period and frequency resource.
What is the difference between MIMO and massive MIMO?
The main difference between SU-MIMO (Single User MIMO) and MU-MIMO is that SU-MIMO allows only a pair of wireless devices to simultaneously send or receive multiple data streams. While MU-MIMO allows multiple wireless devices to simultaneously receive the multiple data streams.
Which technology is used in massive MIMO in 5G?
With the massive number of antenna elements in a massive MIMO system, beamforming becomes “3D Beamforming.” 3D Beamforming creates horizontal and vertical beams toward users, increasing data rates (and capacity) for all users — even those located in the top floors of high-rise buildings (see illustration below).
Which technologies are used in massive MIMO?
What are the different benefits of massive MIMO?
Some of the benefits of massive MIMO technology are: Spectral Efficiency: Massive MIMO provides higher spectral efficiency by allowing its antenna array to focus narrow beams towards a user. Spectral efficiency more than ten times better than the current MIMO system used for 4G/LTE can be achieved.