Arun Kumar¹, Mahmoud A. Albreem², Mohammed H. Alsharif³, Abu Jahid⁴, Peerapong Uthansakul^5,*, Jamel Nebhen⁶

CMC-Computers, Materials & Continua, Vol.67, No.3, pp. 3283-3292, 2021, DOI:10.32604/cmc.2021.015470

Abstract Non-orthogonal multiple access (NOMA) is a strong contender multicarrier waveform technique for the fifth generation (5G) communication system. The high peak-to-average power ratio (PAPR) is a serious concern in designing the NOMA waveform. However, the arrangement of NOMA is different from the orthogonal frequency division multiplexing. Thus, traditional reduction methods cannot be applied to NOMA. A partial transmission sequence (PTS) is commonly utilized to minimize the PAPR of the transmitting NOMA symbol. The choice phase aspect in the PTS is the only non-linear optimization obstacle that creates a huge computational complication due to the respective non-carrying sub-blocks in the unitary… More >

Yinghua Zhang^1,2, Jian Liu¹, Yunfeng Peng¹, Yanfang Dong², Changming Zhao^3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.1, pp. 239-257, 2020, DOI:10.32604/cmes.2020.010778

Abstract Aiming for ultra-reliable low-latency wireless communications required in industrial internet of things (IIoT) applications, this paper studies a simple cognitive radio non-orthogonal multiple access (CR-NOMA) downlink system. This system consists of two secondary users (SUs) dynamically interfered by the primary user (PU), and its performance is characterized by the outage probability of the SU communications. This outage probability is calculated under two conditions where, a) the transmission of PU starts after the channel state information (CSI) is acquired, so the base station (BS) is oblivious of the interference, and b) when the BS is aware of the PU interference, and… More >

Yinghua Zhang^1,2, Yanfang Dong², Lei Wang¹, Jian Liu^1,*, Yunfeng Peng¹, Jim Feng³

CMC-Computers, Materials & Continua, Vol.60, No.1, pp. 379-393, 2019, DOI:10.32604/cmc.2019.05790

Abstract In this paper, we propose a downlink cognitive non-orthogonal multiple access (NOMA) network, where the secondary users (SUs) operate in underlay mode. In the network, secondary transmitter employs NOMA signaling for downlink transmission, and the primary user (PU) is interfered by the transmission from SU. The expressions for the outage probabilities are derived in closed-form for both primary and secondary users in the presence of channel estimation error. Numerical simulation results show that the channel estimation error and the inter-network interference cause degradation of the downlink outage performance. Also the power allocation and the location have a significant impact on… More >