Shape of time domain signal is a deciding factor for ultra wide band (UWB) application in ground penetrating radar scenario. Ricker wavelet provides a good amount of desired bandwidth for geo radar application. Power content in 3db bandwidth and bandwidth equal to inverse of pulse width is more for Ricker wavelet in comparison to other shape of signal. Shaping of the short UWB impulse maximizes the transmit power. Very low Lower cut off frequency is a challenging issue for hardware design prospective if hardware has a very high upper cut-off frequency like a vector network analyzer (VNA). Time domain pulse shaping provides multiple advantageous features like range detection of target, electrical parameter measurement of soil, spatial resolution improvement etc in geo radar application. This paper describes a comparative study of other shape of pulses to Ricker wavelet i.e. (double derivative of Gaussian signal).

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Recent challenging channel estimation for antenna beam shape MIMO without performance loss is to be improved. In this paper, a fully scheduled decomposition-based channel estimation scheme is proposed by using the concept of MIMO with position-orthogonal multiple access (POMA) system. Furthermore, to improve power allocation, an iterative power decomposition is proposed by giving solution to power optimization problem. The proposed work channel estimation achieves better comparisons.

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Non-reciprocity limits the potential of time division duplexing (TDD) massive multiple-input and multiple-output (MIMO) systems. Due to the reciprocal channel, there is no need for downlink (DL) pilot transmission implies computational complexity reduction and saving precious time resources. In this study, the DL channel matrix is estimated using the uplink channel matrix by a novel reciprocity calibration technique. Non-reciprocity arises due to the hardware mismatch (HM) across the base station (BS) and the user terminal (UT)/both. Its detrimental effect causes amplitude and phase impairment in the downlink signal transmission. Since a massive MIMO network has a large number of antenna elements across the BS, hence the instantaneous HM coefficient cannot be determined accurately. For solving such a problem, the authors use the statistical response of the hardware unit. Considering a complex Gaussian hardware response across each antenna terminal, the probability density function (PDF) of amplitude and phase mismatch is derived. They also derive the joint PDF of amplitude and phase mismatch, considering the HM. Simulation results address the sensitivity and complexity for evaluating the sum-rate capacity under three linear precoders (matched filter, regularized zero-forcing, and zero-forcing), which validate their effectiveness in this scenario.