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Spatial Modulation for Non-Orthogonal Multiple Access based IoT Networks
Irfan Azam,Soo Young Shin 한국통신학회 2022 한국통신학회 학술대회논문집 Vol.2022 No.2
This paper presents a spatial modulation (SM) scheme for non-orthogonal multiple access (NOMA) based internet of things (IoT) networks is proposed. Mostly, the data in conventional SM-NOMA is transmitted using multiple antennas depending on the data of the users. However, in the mixed unicast-multicast transmission the data is transmitted to both type of users. In the proposed scheme the multicast data is transmitted using the proposed SM-NOMA scheme which saves the total transmit power of the base station (BS). The results show that the proposed scheme outperforms in mixed unicast-multicast transmission.
Cell-free UAV Communication in 6G Wireless Networks
Irfan Azam,Soo Young Shin 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.2
Due to limited communication capabilities, network-centric (NC) models do not fit for the sixth generation (6G) wireless communication systems. This paper presents a cell-free appraoach for unmanned aerial vehicle (UAV) communication in a non-orthogonal multiple access (NOMA) network where multiple UAV base stations (BS) serve a large number of ground users through a user-centric (UC) approach. Importantly, clustering is performed using a linear regression algorithm to find the best optimal location for the UAV BS so that maximum user coverage is provided. The simulation results show that the proposed technique performs better than the NC approach and maximizes the sum rate.
Media-based modulation aided uplink NOMA for massive machine-type communications
Irfan Azam,I Nyoman Apraz Ramatryana,Soo Young Shin 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6
This paper presents a novel media-based modulation (MBM) aided uplink non-orthogonal multiple access (NOMA) technique for massive machine-type communications (mMTC). NOMA supports massive connectivity while MBM as a modulation technique provides high spectral and energy efficiency. In the proposed MBM-NOMA, users are equipped with a single transmit antenna surrounded by multiple radio frequency (RF) mirrors while a base station (BS) is equipped with multiple receive antennas for uplink NOMA communication. Maximum-likelihood (ML) estimation technique with successive interference cancellation (SIC) is used at the receiver to detect the MBM-NOMA signals. Performance of the proposed MBM-NOMA is analyzed in terms of bit error rate (BER) and is compared with the conventional SIC based NOMA technique. It is shown that MBM-NOMA outperforms conventional NOMA in terms of error performance, achievable transmission rate and energy efficiency.
On the performance of SIC-free spatial modulation aided uplink NOMA under imperfect CSI
Irfan Azam,Soo Young Shin 한국통신학회 2023 ICT Express Vol.9 No.1
In this paper, a spatial modulation aided uplink non-orthogonal multiple access (SM-NOMA) without successive interference cancellation (SIC) is proposed. The SIC-free SM-NOMA system is investigated under both perfect and imperfect channel state information (CSI). Moreover, on the receiver side, both SIC-based and SIC-free detection techniques are used to analyze the bit error rate (BER) performance of SM-NOMA. Finally, the performance of SIC-free SM-NOMA is evaluated and compared with the conventional NOMA, and SIC-based SM-NOMA. The results show that the SIC-free SM-NOMA outperforms conventional NOMA in terms of spectral efficiency, energy efficiency, and BER.
Madiha Makhdoom,Muhammad Imran Jamil,Sikander Azam,Muhammad Irfan,Zeesham Abbas,Banat Gul,Saleem Ayaz Khan,Xiaotian Wang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.12
A hydrogen storage material can also be used as a potential and effective solid reducing agent in addition to its applications as an important energy carrier. The density function theory has been used to find the structural and optoelectronic properties of the Li$_{2}$NH compound. The exchange-correlation functional based GGA (generalized gradient approximation) is applied for calculating structural and optoelectronic properties. The expression for the formation is used to identify the stability, which is further confirmed by calculating the structural properties of Li$_{2}$NH. The calculations of the band structure show that a direct band gap is present between the occupied Li and N orbitals. A deep analysis of the optical properties was performed under incident photon radiation at energies up to 14 eV. Our calculated refractive index $n$(0) and the static part of the dielectric constant $\varepsilon_{2}$(0) are analogous to the experimental and other reported theoretical value.