The unquenchable demand for high-speed mobile data has put today’s cellular base stations in a tight spot. In many urban areas with dense populations, increasing the number of users per cell and continuously accelerating the transmission and reception data rates are still major challenges. These have led to the formation of 5G, the next generation of wireless networks. 5G is expected to handle far more traffic at much higher speeds than the base stations that make up our existing cellular networks.
5G requires a brand new network structure for more selective use of bandwidth. It will require new technologies to compensate the propagation losses at high frequencies and to connect significant amount of users and devices. Two of those technologies, beamforming and massive Multiple Input Multiple Output (MIMO) are critical for increasing spectral efficiencies and providing reliable coverage. They help in reducing interference along with directing and amplifying signals.
Cellular signals, especially those carried by millimetre waves can be easily blocked by obstacles and lose their signal strength over long distances. Beamforming addresses this problem by turning these signals into concentrated beams and reinforcing them in a particular direction, rather than having the signals spread in all directions at the same time from the broadcast antenna. Beamforming uses multiple antennas broadcasting the same signal at slightly different times. Relative amplitude and phase shifts are applied to the antenna elements so that the output signals from the antenna array add together coherently for a particular transmission or reception angle and cancel each other out for other signals. Thus it acts as a traffic signalling system that identifies the most efficient data delivery route to the destination and reduces interferences. The limitations of beamforming involve the requirement of its advanced computing resources and hardware complexity. But improved processor power and efficiency have made beamforming techniques affordable enough to make consumer networking equipment.
In 5G, beamforming can act as a support to massive MIMO. MIMO uses multiple antennas for both transmission and reception. These antennas are linked in a way to minimize error and maximize efficiency of a network. In short MIMO refers to a practical technique for sending and receiving multiple data signals at the same time and frequency over a radio channel through multiple paths. MIMO systems have been used in wireless communications for a long time to enhance connectivity, speed and user experience. Massive MIMO is an extention of conventional MIMO in which base stations have large antenna arrays. The signals from these antennas may be reflected off by buildings and other obstacles thereby leading to its delay, attenuation or both on reaching the receiver end. Thus the primary challenge of massive MIMO is to reduce the interference while transmitting huge number of signals from many antennas. For this purpose, massive MIMO uses beamforming to make sure the signals from the source is efficiently targeted to its destination.
The transmission and reception of signal energy are focussed on small regions of space thereby proving high efficiency and throughput. The focussed beam of signals become finer with the increase in the number of antennas used. Thus with the help of beamforming, many users and antennas on a massive MIMO array can exchange large amount of information at once in a precisely coordinated pattern. One of the major limitations of Massive MIMO is the development of antennas with low cost and high precision. Also, the complexity of massive MIMO makes it difficult to undertake meaningful testing.
The resource management capability of 5G outsmarts previous generations of mobile communication systems. Massive MIMO and beamforming technologies indeed have significant advantages in terms of network capacity and spectral efficiency, resulting in low latency levels across the networks. Incorporating these technologies, 5G has the potential to become a game-changing generation of cellular networks, opening the door for a promising digital world.
Read PART 2 of the series- “EXPLORING 5G : PART 2- MILLIMETER WAVES explained“
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