Further, the preconditioner given in[18] is based on a truncated basis expansion model (BEM) which is usually used for the approximation of a narrowband time-varying channel.
However, the OFDM signal features large amplitude variations compared to that of the single carrier's signal, because it is the sum of many narrowband signals in the time domain, with different amplitudes.
X m, k) is a T-F transformed narrowband signal (with the time index m) coming out of the k th channel: DSTFT x n = X m, k = ∑ n = 0 K - 1 x n w m M - n e - j 2 π n k / K k = 0, …, K - 1, (1).
The received signal for a time-invariant narrowband system combining with MIMO (MIMO-NB system) is described as follows [33]: Y = HX + W (2) H = h 11 h 12 h 13 … h 1 N t h 21 h 22 h 33 … h 2 N t h 21 h 22 h 33 … h 3 N t ⋮ ⋮ ⋮ ⋱ ⋮ h N r 1 h N r 2 h N r 3 … h N r N t (3).
Based on energy detector for narrowband sensing, the sensing time and detection thresholds for each narrowband detector are optimized jointly, which is different from the previous multiband joint detection framework in [44].
We use the narrowband MI at frequency and time, which is defined as (7).
First, we employ EMD to decompose nonstationary single-trial time series into narrowband components called intrinsic mode functions (IMFs) with time scales dependent on the data.
During the m th PRB, the beamforming vector applied at the eNodeB W i (m) with i = {1,2,3,…,Mt} is constant because the narrowband PRBs in frequency and time domain may experience flat fading.
The final target model gives good agreement with the narrowband data set on all time scales examined.
Results showed that multifrequency and multistatic radars could achieve sufficient resolution using several narrowband transmitters and a long integration time.
A novel photorefractive wavelength demultiplexing scheme for optical communications and spectroscopy applications has been proposed and experimentally demonstrated for the first time, by using the narrowband filtering and demultiplexing properties of volume holographic gratings formed in LiNbO3 Fe crystal.
