Estimation Techniques for MIMO-OFDM-A Review

In the context of Third-Generation Partnership Project Long-Term Evolution (3GPP LTE), the target data rates are 100 Mb/s in downlink and 50 Mb/s in uplink, and other system features include flexible bandwidths and moderate power consumption of mobile terminals. While the previous 3GPP generations, namely, 3G UMTS and 3.5G HSPA, rely on code-division multiple access (CDMA), LTE adopts orthogonal frequency-division multiple access (OFDMA)-based technologies for its uplink and downlink. Due to high peak-to-average power ratio (PAPR) of OFDMA signals, the single- carrier frequency division multiple access (SC-FDMA), also known as discrete Fourier transform (DFT)-spread OFDMA, has been selected for the uplink transmission in 3GPP LTE systems. SC-FDMA has similar throughput performance as OFDMA but with lower PAPR to increase power efficiency and is less sensitive to frequency synchronization errors, which makes it favorable for mobile terminals.

Multiuser Scheduling In 3GPP LTE-A Uplink Non-Stand-Alone Cellular Network With Virtual MIMO

New 5G architecture gives access to New Radio (NR) with co-exist LTE. 3GPP LTE-A transition towards NR is a wireless technology that is widely employed in the cellular mobile network to support significantly high volume traffic. In this paper, we propose the best N-subset reduction and a modified RME algorithm (BNSRME) as an uplink multiuser scheduler. It is responsible for allocating resources among the active users in the most effective manner. The N-subset reduction method selects the best chunk of continuous resource blocks from the available system bandwidth. Users are assigned chunks based on channel-dependent selection and utility function. The BNSRME scheduling algorithm aims to optimize performance, spectral efficiency, and allows multiuser scheduling where multiple active users are allocated the same time-frequency resources. We consider the threshold cap SNRT to improve sensitivity quality for satisfactory users. The approach is MU scheduling which will be the most commonly deployed in non-stand-alone (NSA) 5G uplink cellular network. The result shows that the system spectral efficiency improves by 32.55 % by using the proposed multiuser algorithm compared to single user scheduling in an uplink. It has been shown that its performance can be further improved by using the MU-MIMO system.