A review on massive MIMO antennas for 5G communication systems on challenges and limitations

High data rate transfers, high-definition streaming, high-speed internet, and the expanding of the infrastructure such as the ultra-broadband communication systems in wireless communication have become a demand to be considered in improving quality of service and increase the capacity supporting gigabytes bitrate. Massive Multiple-Input MultipleOutput (MIMO) systems technology is evolving from MIMO systems and becoming a high demand for fifth-generation (5G) communication systems and keep expanding further. In the near future, massive MIMO systems could be the main wireless systems of communications technology and can be considered as a key technology to the system in daily lives. The arrangement of the huge number of antenna elements at the base station (BS) for uplink and downlink to support the MIMO systems in increasing its capacity is called a Massive MIMO system, which refers to the vast provisioning of antenna elements at base stations over the number of the single antenna of user equipment. Massive MIMO depends on spatial multiplexing and diversity gain in serving users with simple processing signal of uplink and downlink at the BS. There are challenges in massive MIMO system even though it contains numerous number of antennas, such as channel estimation need to be accurate, precoding at the BS, and signal detection which is related to the first two items. On the other hand, in supporting wideband cellular communication systems and enabling low latency communications and multigigabit data rates, the Millimeter-wave (mmWave) technology has been utilized. Also, it is widely influenced the potential of the fifth-generation (5G) New Radio (NR) standard. This study was specifically review and compare on a few designs and methodologies on massive MIMO antenna communication systems. There are three limitations of those antennas were identified to be used for future improvement and to be proposed in designing the massive MIMO antenna systems. A few suggestions to improve the weaknesses and to overcome the challenges have been proposed for future considerations

A review on massive MIMO Antennas for 5G communication systems on challenges and limitations

High data rate transfers, high-definition streaming, high-speed internet, and the expanding of the infrastructure such as the ultra-broadband communication systems in wireless communication have become a demand to be considered in improving quality of service and increase the capacity supporting gigabytes bitrate. Massive Multiple-Input Multiple-Output (MIMO) systems technology is evolving from MIMO systems and becoming a high demand for fifth-generation (5G) communication systems and keep expanding further. In the near future, massive MIMO systems could be the main wireless systems of communications technology and can be considered as a key technology to the system in daily lives. The arrangement of the huge number of antenna elements at the base station (BS) for uplink and downlink to support the MIMO systems in increasing its capacity is called a Massive MIMO system, which refers to the vast provisioning of antenna elements at base stations over the number of the single antenna of user equipment. Massive MIMO depends on spatial multiplexing and diversity gain in serving users with simple processing signal of uplink and downlink at the BS. There are challenges in massive MIMO system even though it contains numerous number of antennas, such as channel estimation need to be accurate, precoding at the BS, and signal detection which is related to the first two items. On the other hand, in supporting wideband cellular communication systems and enabling low latency communications and multi-gigabit data rates, the Millimeter-wave (mmWave) technology has been utilized. Also, it is widely influenced the potential of the fifth-generation (5G) New Radio (NR) standard. This study was specifically review and compare on a few designs and methodologies on massive MIMO antenna communication systems. There are three limitations of those antennas were identified to be used for future improvement and to be proposed in designing the massive MIMO antenna systems. A few suggestions to improve the weaknesses and to overcome the challenges have been proposed for future consideration

Flexible Backhauling with Massive MIMO for Ultra-Dense Networks

One of the main challenges for wide-scale deployment and timely adoption of ultra-dense networks (UDNs) in future 5G is the backhaul. Typically, mmW technologies for backhaul require line-of-sight conditions while high-capacity wired based solutions need a significant investment in infrastructure. Such limitations pose practical constrains on the scalability of UDNs and increase the deployment cost of dense networks. In this paper, we consider in-band backhaul for UDNs based on massive MIMO systems in sub-6GHz. In particular, we propose a scheme for allowing simultaneous downlink transmissions in backhaul and access network on a single frequency-band that exploits a novel combination of state-of-the-art practical transmit and receive beamforming techniques. A novel frame structure for allowing a co-existence between massive MIMO based backhaul and UDNs is also proposed. Moreover, a solution for in-band uplink transmissions that exploits time-division-duplex (TDD) and spatial multiple-access is also provided. Extensive numerical results using a realistic system-level simulator are given. Results show that the performance of a UDN with the proposed inband backhaul scheme reaches ~58% of the throughput of a similar access network with ideal (e.g., wired) backhaul. Our results also show that the proposed scheme provides an increase in throughput of ~30% compared to a time division duplex (TDD) scheme for in-band backhaul. Further advantages of the proposed massive MIMO based in-band backhaul scheme for UDNs include reusing both the (scarce) spectrum in sub-6GHz and acquired macro-sites, thus providing a seamless transition from LTE to 5G networks.Peer reviewe