Received: August 21, 2018 310 International Journal of Intelligent Engineering and Systems, Vol.12, No.1, 2019 DOI: 10.22266/ijies2019.0228.30 Massive MIMO: Enhancement of Spectral and Energy Efficiency for 5G Perspective Prasad Rayi 1 * Makkapati Venkata Siva Prasad 2 1 Acharya Nagarjuna University, Guntur, International School of Technology and Sciences for Women, Rajanagaram, India 2 Rayapati Venkata Rangarao & Jagarlamudi Chandramouli College of Engineering, Guntur, India * Corresponding author’s Email: prasadrayi@gmail.com Abstract: Massive Multi-Input and Multi-Output (MIMO) antenna system is considered as the key technology to improve both spectral efficiency (SE) and energy efficiency (EE) for 5G wireless systems. This paper evaluates the impact of perfect and imperfect channel state information (CSI) on the SE. The maximum SE of 200 bits/s/Hz achieved in a multi-cell scenario and its limiting factors were explored. We mainly demonstrated linear precoding algorithms such as zero-forcing (ZF), maximum ratio combing (MRC), and minimum mean square error (MMSE) for SE analysis. The explicit SE and EE expressions were derived from Shannon capacity calculations for single and multi-cell scenario. The proposed ZF and MRC precoding schemes were observed with SEs of 185 bit/s/Hz, and 180 bits/s/Hz respectively with pilot reuse factor with λ=7. The simulation results were validated by comparing the SE versus the number of base station (BS) antennas with receiving schemes by using MATLAB 2018a. Keywords: Spectral efficiency, Energy efficiency, Multi input and multi output, Channel state information, 5G. 1. Introduction Current cellular networks demand high-speed transmission with multi-user capability under interference and noise scenario. Massive multi-input and multi-output (MIMO) can improve the spectral efficiency (SE) by serving a large number of users in a cell within the same time and bandwidth. Massive MIMO is a technology with massive antennas deploying at the base station (BS) to improve SE and energy efficiency (EE) [1]. Higher data rate has achieved with prominent parameters such as a greater spectrum (Hz), larger cell density (cells/Km 2 ), high EE and SE [2, 3]. The combination of a millimetre (mm)-wave communication and massive MIMO is the most promising technology for future wireless communication [4]. This combined technology can integrate and enable several schemes into one platform. Several pieces of recent research have reported [5, 6] to achieve high SE and EE in the fifth generation (5G) systems and also offer high data rate over the 4G systems. The EE of the downlink (DL) mm-wave massive MIMO communication can be improved by employing hybrid-beam forming schemes [7] with reduced interference from other user terminals (UT)s. To the best of our knowledge, the achievable rate of massive MIMO mainly depends on perfect channel state information (CSI) available at the UT and the BS. However, acquiring the perfect CSI is highly limited by the coherence time and pilot contamination (PC) [8, 9] in large antenna systems. The impact of interference with PC is presented in [10] on the cells and UTs. It is required to obtain a maximum signal to interference plus noise ratio (SINR) to increase the SE. Since the SE strongly depends on the channel data rate. In addition to this, resource allocation also plays a key role to attain the maximum SE and EE [11 - 13]. The power allocation schemes were proposed [14] to reduce the interference both from the primary and the secondary UTs. The network