A Retrospection of Channel Estimation Techniques for 5G Wireless Communications: Opportunities and Challenges
The fifth-generation (5G) network is expected to support a significantly large amount of mobile data traffic and a huge number of wireless connections, to achieve better spectrum, energy-efficiency, as well as the quality of service (QoS) in terms of delay, reliability, and security. Massive Multiple-input Multiple-output (mMIMO) is an emerging technology for the 5G wireless communication systems. It has the potential to provide high spectral efficiency and improved link reliability and accommodate a large number of users also aiming at the efficiency, accuracy, and estimation of channel many channel estimation (CE) techniques are developed. In most cases, the emphasis of most proposed CE schemes is to improve the CE performance and complexity for ensuring quality signal reception and improved system throughput. In the review article, channel estimation techniques are studied and investigated for massive MIMO systems. A comparison is also shown among the different channel estimation techniques.