Abstract—Among the technologies that play an important role in improving the Signal-to-Interference and Noise Ratio (SINR) and improving network efficiency are carrier aggregation and millimeter wave (mmWave) technologies, despite some limitations, such as limited coverage of less than 200 meters. This research specifically examines the combined effect of carrier aggregation and mmWave technologies. The results demonstrate significant improvements in both SINR and spectral efficiency when these two technologies are used together. Furthermore, the study reveals that the choice of carrier in carrier aggregation is not random, but rather depends on network conditions and frequency availability. The study also highlights the importance of choosing the appropriate numerology value, as it directly affects the bandwidth of each carrier, which in turn impacts the spectral use and SINR. The study also examines the negative effects of Doppler shift on mobile phone users, especially as they become more mobile. It has been observed that an increase in the number of users contributes to increased interference and decreased signal quality due to the combined effects of mobility and user interference, thereby negatively impacting radio performance. This research provides valuable insights into optimal carrier selection strategies under different network conditions and confirms the effectiveness of combining carrier aggregation with mmWave technology to mitigate performance degradation caused by the Doppler effect.

Keywords—carrier aggregation, mmWave, SIMU5G, spectral efficiency, doppler shift

Cite: Zuhor Maher Ismail and Saad Ahmed Ayoob, “Analyzing the Doppler Effect on Carrier Aggregation and Millimeter-Wave Performance in 5G Systems," Journal of Communications, vol. 20, no. 5, pp. 549-559, 2025.


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