Better spectral efficiency of device to device underlying massive multi‐input multi‐output using receiver filter algorithm and power control model

Abstract

Summary Benefits of device to device (D2D) underlying massive multi‐input multi‐output (MIMO) cellular networks are noticeable in the fifth generation (5G) of mobile broadband networks. However, the interference of such coexistence from massive MIMO and D2D, due to resource sharing between cellular users and D2D users, should be decreased. Because of this issue, the spectral efficiency of such networks will be reduced. The challenges of such networks are to control the transmit power of their users and to mitigate cellular‐to‐D2D and D2D‐to‐cellular interferences. In this paper, we introduce two techniques to enhance the performance of these systems. Since, we propose a linear receiver filter with a special structure in such coexistence network to increase intended signal and then to increase spectral efficiency. Also, in this research, to decrease the whole interference, by explaining power sets for cellular and D2D transmitter for various distance intervals, we apply an open loop power control approach in the uplink as a suboptimal solution. This solution is a closed‐form solution and is often more useful and take lower time than the optimal solution. Also, we analyze spectral efficiency for the cellular uplink of such networks with the proposed frameworks. Numerical results approve that the two proposed techniques decrease the interferences. Simulation results demonstrate an enhancement in the cellular spectral efficiency.

Low‐complexity linear precoding for low‐PAPR massive MU‐MIMO‐OFDM downlink systems

“…In order not to damage the transmission quality (i.e., perfect MUI), the added PCSs {r n } are constrained to lie in the null spaces of their associated MIMO channel matrices such that they do not disturb the signals received by M r users through the jχj active subcarriers. Thereby, the precoded version c n ¼ V n r n is added to the precoded data instead of e n , as shown in Equation (1), where V n represents the nth MIMO channel null space. In addition, r n has to respect the OOB constraint such that it has to be set to zero on the guard band, as shown by the following equation:…”

“…Moreover, massive MU-MIMO enables the use of low-cost and low-power single-antenna user devices while expensive equipment is only needed on the base station (BS), leading to a higher energy efficiency compared to the classical single-input single-output (SISO) and MU-MIMO technologies. 1,3 Indeed, linear spatial precoders, such as matched filter (MF), zero-forcing (ZF), and regularized ZF (RZF), which can be used in downlink, have the potential to reduce the operational power consumption at the transmitter and enable the suppression of MU interference (MUI). 4 In addition, massive MIMO has been shown to support both orthogonal multiple access (OMA) and nonorthogonal OMA (NOMA), 5,6 such feature is substantial for the next 6G wireless communications.…”

“…Massive multiuser multiple‐input multiple‐output (MU‐MIMO) has been recognized as the most promising wireless communication technology for the future/sixth generation (6G) systems. It is also know as large‐scale MU‐MIMO and was initially introduced in Heydari et al 1 and Li et al, 2 where the number of antennas employed at the BS is sufficiently higher than the number of served users. Then, we can likely get the spectral efficiency to grow proportional to the number of users.…”

“…Then, we can likely get the spectral efficiency to grow proportional to the number of users. Moreover, massive MU‐MIMO enables the use of low‐cost and low‐power single‐antenna user devices while expensive equipment is only needed on the base station (BS), leading to a higher energy efficiency compared to the classical single‐input single‐output (SISO) and MU‐MIMO technologies 1,3 . Indeed, linear spatial precoders, such as matched filter (MF), zero‐forcing (ZF), and regularized ZF (RZF), which can be used in downlink, have the potential to reduce the operational power consumption at the transmitter and enable the suppression of MU interference (MUI) 4 .…”