Publications
- M. Madhuri Latha, Sai Krishna Charan Dara and Sachin Chaudhari, “Beamformed Sensing using Dominant DoA in Cognitive mmWave Network”, Accepted in IEEE ANTS Conference 2020
Abstract: -
- In this paper, we propose spectrum sensing schemes for a secondary user (SU) with multiple antennas to detect a primary user (PU) transmission in a cognitive mmWave network. The channel model considered at mmWave carrier frequencies is the clustered Rician fading channel, which has few multipaths. For the considered scenario, we propose three beamformed energy detection (BFED) schemes where beamforming is done in the dominant direction of arrival (DoA)at the SU and then energy detection (ED) is applied. The three schemes differ in the amount of information assumed about the DoAs at the SU. The performance of these schemes has been compared with the traditional ED and maximal ratio combining (MRC) schemes for multiantenna systems. It is shown through simulations that the proposed BFED approaches provide significant performance gains over the ED and negligible loss as compared to the MRC, which makes an impractical assumption of the channel between the PU and the SU to be exactly known.
- M. Madhuri Latha, Sai Krishna Charan Dara and Sachin Chaudhari, “Beamformed Energy Detection in the Presence of an Interferer for Cognitive mmWave Network”, Accepted in IEEE VTC - Fall Conference 2021
Abstract: -
- In this paper, we propose beamformed energy detection (BFED) spectrum sensing scheme for a single secondary user (SU) or a cognitive radio (CR) to detect a primary user (PU) transmission in presence of an interferer. The extended Saleh-Valenzuela channel model is used to model the mmWave channel for the considered scenario. In the mmWave band due to high attenuation, there are fewer multipaths and the channel is sparse giving rise to fewer directions of arrivals (DoAs). Sensing in only these paths instead of blind energy detection can reap significant benefits. An analog beamforming weight vector is designed such that beamforming gain in the true DoAs of the PU signal is maximized while minimizing interference from the interferer. For this, a single objective function, which is a weighted sum of the two objective functions related to beamforming gain and interference, is formed. The proposed sensing scheme is designed under the knowledge of full CSI at the SU for the PU-SU and Interferer-SU channels. However, as the channel information may not be available at the SU, a second BFED sensing scheme is also proposed when no CSI is available, which only tries to estimate the DoAs to reduce the computational complexity. To model the estimates of DoAs, perturbations are added to the true DoAs. The distribution of the test statistics for both the proposed BFED schemes is derived under the null hypothesis so that the threshold of the Neyman-Pearson detector can be found analytically. The performance of both schemes is also compared with the traditional energy detector for multi-antenna systems.