Sum-MSE Gain of DFT-Based Channel Estimator Over Frequency-Domain LS One in Full-Duplex OFDM Systems

Abstract

In this paper, we make an investigation on the summean-square-error (sum-MSE) performance gain achieved by DFT-based least-square (LS) channel estimator over frequencydomain LS one in full-duplex OFDM system in the presence of colored interference and noise. The closed-form expression of the sum-MSE performance gain is given. Its simple upper and lower bounds are derived by using inequalities of matrix eigen-values. By simulation and analysis, the upper lower bound is shown to be close to the exact value of MSE gain as the ratio of the number N of total subcarriers to the cyclic prefix length L grows and the correlation factor of colored interference increases. More importantly, we also find that the MSE gain varies from one to N/L as the correlation among colored interferences decreases gradually. According to theoretical analysis, we also find the MSE gain has very simple forms in two extreme scenarios. In the first extreme case that the colored interferences over all subchannels are fully correlated, i.e., their covariance matrix is a matrix of allones, the sum-MSE gain reduces to 1. In other words, there is no performance gain. In the second extreme case that the coloredinterference covariance matrix is an identity matrix, i.e, they are mutually independent, the achievable sum-MSE performance gain is N/L. A large ratio N/L will achieve a significant sum-MSE gain.

In-Band Full-Duplex Discriminatory Channel Estimation Using MMSE

“…Therefore, such a high number of errors at the physical layer will make the received information useless. Even for N e = 12, the eavesdropper is unable to acquire robust information as its BER is still close to 0.1, because increasing the number of eavesdropping antennas does not improve the channel estimates as shown in (24). Fig.…”

“…It is bandwidth efficient as compared to other schemes because, instead of artificial noise, fullduplex transmission has been used to induce ambiguity at the eavesdropper while acquiring channel estimates at the legitimate nodes. The existing works for in-band full-duplex channel estimation have been presented in [23], [24], but the existing works are oblivious of the secrecy requirements to achieve discriminatory channel estimation performance at the eavesdropper as compared to the legitimate receiver.…”

Effect of Doppler Shift on the Performance of Multicell Full-Duplex Massive MIMO Networks

“…In addition, it is pointed out that if the BS can obtain the ideal channel state information (CSI), the transmit power per user can be reduced 1/M , and if the BS needs to estimate the channel, the transmit power per user can be reduced to 1/ √ M . On the other hand, the full-duplex technology can increase the spectrum efficiency of the system by nearly twice, while the premise is that it can effectively remove or suppress selfinterference (SI) (e.g., the cofrequency interference) [5], [6]. Because of the extreme performance requirements in the 5G wireless networks, the use of a single item often fails to meet these demands.…”