Time reversal method has been recently considered with great interest due to its ability of the receiver complexity mitigation in the UWB communication systems. However, the channel imperfection (Imperfect CSI) has the destroyed effects on the time-reversed UWB communic More
Time reversal method has been recently considered with great interest due to its ability of the receiver complexity mitigation in the UWB communication systems. However, the channel imperfection (Imperfect CSI) has the destroyed effects on the time-reversed UWB communication system performance. In this paper, at first the BER equations have been calculated in the TiR-UWB systems with the simple matched filter receiver in an imperfect CSI scenario. Then, a two-stage algorithm is proposed to improve the TiR-UWB in such conditions. First stage of mentioned algorithm provides the pre-filter coefficients derivation based on MMSE criteria via channel estimation error covariance matrix and then, an iterative routine is obtained in second stage via the simple matched filter receiver based on the derived coefficients in first stage. Finally, exhaustive simulations are done to demonstrate the performance advantage attained by the improved algorithm. As an especial case, the TiR-UWB system performance is improved by the proposed algorithm in 3 steps.
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Much attention has recently been paid to methods of shared secret key generation that exploit the random characteristics of the amplitude and phase of a received signal and common channel symmetry in wireless communication systems. Protocols based on the phase of a rece More
Much attention has recently been paid to methods of shared secret key generation that exploit the random characteristics of the amplitude and phase of a received signal and common channel symmetry in wireless communication systems. Protocols based on the phase of a received signal, due to the uniform distribution phase of fading channel, are suitable in both static and dynamic environments and, they have a key generation rate (KGR) higher than protocols based on received signal strength (RSS).In addition, previous works have generally focused on key generation protocol for single-antenna (SISO) systems but these have not produced a significant KGR. So in this paper to increase the randomness and key generation rate are used received signal phase estimations on multiple-antenna (MIMO) systems because they have the potential to present more random variables in key generation compared to SISO systems. The results of simulation show that the KGR of the proposed protocol is 4 and 9 times more than the KGR of a SISO system, when the numbers of transmitter and receiver antennas are the same and equal to 2 and 3, respectively. Also, the key generation rate will increase considerably, when to extract the secret key bits using multilevel quantization.
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