Range Dividing MIMO Waveform for Improving Tracking Performance

A multiple-input multiple-output (MIMO) method that shares the same frequency band can efficiently increase radar performance. An essential element of a MIMO radar is the orthogonality of the waveform. Typically, orthogonality is obtained by spreading different signals into divided domains such as in time-domain multiplexing, frequency-domain multiplexing, and code domain multiplexing. This paper proposes a method of spreading the interference signals outside the range bins of interest for pulse doppler radars. This is achieved by changing the pulse repetition frequency under certain constraints, and an additional gain can be obtained by doppler processing. This method is very effective for improving the angular accuracy of the MIMO radar for a small number of air targets, although it may have limitations in use for many targets or in high clutter environments.

Code Domain Non- Orthogonal Multiple Access Schemes for 5G and Beyond Communication Networks: A Review

Future communication networks may encounter various issues in order to facilitate heavy heterogeneous data traffic and large number of users, therefore more advanced multiple access (MA) schemes are being developed to meet the changing requirements. The research space on making more robust MA scheme is continuously increasing, so it becomes significant to analyze the various schemes to determine the appropriate MA scheme for 5G networks. Therefore, in this paper the comprehensive overview of the most popular and recent MA schemes is presented for 5G networks. This paper mainly classifies the MA techniques in orthogonal MA (OMA) and various types of non-OMA (NOMA) techniques. Specifically, we introduce RSMA (Rate splitting multiple access) and IDMA (interleave division multiple access). Further the close attention is paid to NOMA family, including code-domain NOMA (e.g., SCMA (sparse code multiple access)), power-domain NOMA. Above all, from this exploration, the opportunities and challenges could be notified in MA schemes and further the optimum MA technique can be point out among discussed MA schemes for 5G and beyond communication networks.

Intelligent reflected surfaces assisted code domain non-orthogonal multiple access scheme

The propagation medium plays a crucial role in any wireless communication networks, the channel between the transmitter and the receiver, deteriorate the quality of the received signal due to the uncontrollable interactions such as scattering, reflection, and refraction in the channel with the surrounding objects. To overcome this challenge, the recent advent of recongurable intelligent surfaces can be helpful, in which the network operators can control the radio waves, eg, the phase, amplitude, frequency, and even polarization, of the impinging signals without the need of complex decoding, encoding, and radio frequency processing operations. On the other hand, few research papers reported an efficient code domain non orthogonal multiple access (NOMA) such as Interleave division multiple access (IDMA) system for wireless information transfer. Persuaded by the capability of this arising RIS technology, the present article is aimed to provide the modified framework of IDMA (code-domain NOMA) communication system based on RIS technology. Simulation results demonstrate that the proposed system achieves better SNR performance than the conventional IDMA framework.

Effects of Power Allocation and User Mobility on Non-Orthogonal Multiple Access Using Successive Interference Cancellation

This research based on simulation to show impact of the power allocation on Non-Orthogonal Multiple Access (NOMA) using Successive Interference Cancellation (SIC). NOMA used superposition code (SC) on the transmitter and SIC on the receiver. NOMA has two categories power domain (PD) and code domain (CD). This research based on PD-NOMA simulated for downlink. The number of users who use the same recourse block are divided into two conditions: user with apply SIC and without SIC base on the value of channel gain from each user. Applying SC on the transmitter and SIC on the receiver will cancel of interference. Novelties of this research are the best performance of power allocation and user mobility based on parameter BER and SNR. Allocation of the power transmit based on value of channel gain every user, where user with value of channel gain is low will be allocated high power transmit, and otherwise. The best result performance of BER vs SNR used ratio power transmit 0.45 dB:0.55 dB, BER get value SNR for 17 dB and 18 dB. The best performance SNR for mobility of user with speed = 40 km/h value SNR 18 dB for BER . This research has proposed to show impact of power transmit and interference in performance NOMA.