Performance Evaluation of Modulation and Power Allocation Effects on BER in NOMA with SIC over AWGN Channels

2026-01-07T06:46:10SE Asia Standard Time

This study evaluates the performance of a Non-Orthogonal Multiple Access (NOMA) system implementing Successive Interference Cancellation (SIC) over Additive White Gaussian Noise (AWGN) channels, focusing on the effects of modulation schemes and power allocation on Bit Error Rate (BER). Three modulation schemes BPSK, QPSK, and 16QAM are studied in combination with different power allocation configurations (e.g., α = 0.1, 0.3) for two users in an OFDM-based NOMA downlink scenario. The signal superposition process is performed at the transmitter side, while SIC is applied at the receiver side to separate the user signals. The simulation results show that the BER performance is greatly affected by the modulation level and power allocation ratio. Lower-order modulations (such as BPSK and QPSK) provide better performance at low SNR, especially for users with poorer channel quality. On the other hand, improper power distribution can cause error propagation in the SIC process, degrading the demodulation accuracy. This study emphasizes the importance of selecting adaptive modulation schemes and power allocation strategies in NOMA system design. These findings provide important contributions to the development of future wireless communication systems, especially 5G and later generations, which demand high spectral efficiency and multi-user service reliability.

Implementation of Ethereum-Based Blockchain Technology for ADS-B Data Security and Validation

2026-01-07T06:54:28SE Asia Standard Time

Automatic Dependent Surveillance–Broadcast (ADS-B) has significantly enhanced air traffic monitoring by enabling real-time broadcasting of aircraft positions and identifiers. However, its lack of cryptographic safeguards makes it inherently vulnerable to spoofing, replay, and tampering attacks. This study presents a blockchain-based ADS-B validation framework that leverages Ethereum smart contracts and MetaMask for secure, decentralized data authentication. The proposed system validates incoming flight messages by enforcing logical constraints on altitude changes, timestamp order, and geographic displacement using Solidity-coded rules. Each data transaction is subject to a dual-layer security model: automated detection by the smart contract and manual authorization via MetaMask. This ensures that even flagged anomalies cannot be committed without human approval, thus combining operational oversight with blockchain's immutability. The system was tested using flight data from the OpenSky Network, with 56 attack simulations performed across spoofing, replay, and tampering categories. The contract achieved a 92.9% detection rate, with all accepted anomalies intentionally approved to test forensic transparency. Ethereum’s transparent ledger preserved all transaction details, reinforcing its potential for regulatory compliance and incident investigation. The results affirm blockchain’s suitability in protecting aviation telemetry against unauthorized modifications. Future enhancements may include machine learning for anomaly detection, stricter timestamp controls, and integration with global aircraft registries to improve spoofing detection. This implementation bridges theoretical blockchain benefits with operational air traffic requirements.

ITEJ (Information Technology Engineering Journals)

Performance Evaluation of Modulation and Power Allocation Effects on BER in NOMA with SIC over AWGN Channels

Implementation of Ethereum-Based Blockchain Technology for ADS-B Data Security and Validation