Hybrid Transmit and Receive Designs for Massive MIMO Millimeter-Wave Heterogeneous Systems
Authors
Abstract
With the constant increase of mobile communication devices and broadband services, the system requirements are getting more demanding. Long Term Evolution (LTE) Advanced comes as a progressive enhancement to its predecessor LTE, introducing heterogeneous networks (HetNets), which have proven to be great solutions to improve both capacity and coverage. As for 5G, it takes more of a disruptive step, enabling new possibilities, such as connecting people and things. To enable such a step, new technologies and techniques need to be researched and tested. Massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) communications are two of such technologies, as they show promising results such as increased capacity and spectral efficiency. However, due to the mmWave propagation constraints, the existence of ultra-dense HetNet scenarios may be a possibility. When considering ultra-dense scenarios with a massive number of users, the system becomes interference-limited, even using mmWave band. As such, the design of interference mitigation techniques that deal with both inter and intra-tier interference are of the utmost importance. In this dissertation, a low complexity analog-digital hybrid architecture for boththe transmitter and receiver in the uplink scenario is proposed. It is designed for
an ultra-dense heterogeneous system and employing massive MIMO, mmWave
and beamforming techniques in order to mitigate both intra- and inter-tier
interference. Considering the Bit Error Rate (BER) as the performance metric,
the results show that the proposed architecture efficiently removes both inter-
and intra-tier interferences, achieving a result close to its fully digital counterpart.