Underwater acoustic channel time delay estimation method based on orthogonal matching tracking
A technology of orthogonal matching pursuit and delay estimation, which is applied in baseband systems, baseband system components, digital transmission systems, etc., can solve the problems of reducing computational complexity and no application, so as to reduce computational complexity, save energy, low-complexity effects
Active Publication Date: 2019-01-04
HARBIN ENG UNIV
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This method only refers to the classic OMP algorithm for channel estimation, does not significantly reduce the computational complexity, and has not been applied to the field of underwater acoustics
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[0030] The invention relates to an underwater acoustic channel delay estimation method based on orthogonal matching pursuit. The present invention will be described in detail below in conjunction with the accompanying drawings.
[0031] A. CP-OFDM system and underwater acoustic multipath channel model
[0032] The OFDM system involved in the present invention adopts a cyclic prefix mode. It is assumed that an OFDM symbol block contains K subcarriers, and the transmitted symbol on each subcarrier is s[k]. The duration of an OFDM symbol block is T, and the duration of the cyclic prefix is T cp , the carrier frequency is f c . Therefore, the time-domain expression of the OFDM symbol to be transmitted is as follows,
[0033]
[0034] Assuming that the channel remains unchanged within a symbol duration, the channel model in this paper is a multipath channel with L paths, and the amplitude and delay of each path are A l and τ l (l=0,1,...,L-1), and assume the Doppler shi...
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The invention relates to an underwater acoustic channel time delay estimation method based on orthogonal matching tracking. The invention comprises steps: residual r0, a to-be-estimated amplitude vector and a dictionary matrix as described in the specifications and a path index q are initialized, wherein the residual r0 is made to be what is described in the specifications and the path index q ismade to be zero; a sampling interval deltat, the maximum iteration number Q and iteration stopping conditions chi1 and chi2 are inputted; iteration is carried out: precise estimation time delay t<q> and sampling points at two sides are found out by a two-step search model, the obtained sampling points are brought into a continuous time domain inner product function-based time delay estimation model, and to-be-estimated time delay tau<q>-hat is obtained; the obtained to-be-estimated time delay tau<q>-hat is used to construct a new atom as described in the specifications, orthogonalization iscarried out with the previous atom, and a to-be-estimated atom as described in the specifications is obtained; a least square method is used to calculate the amplitude value xi<q>-hat corresponding to the current path q; variables of the residual, the dictionary matrix and the to-be-estimated amplitude vector are updated as described in the specifications; whether an iteration stopping conditionas described in the specifications is met is judged; and a channel estimation result as described in the specifications is outputted. Thus, the time delay estimation precision can be improved while the computational complexity is reduced, and a channel estimation model with high efficiency, high precision and low complexity can be realized.
Description
technical field [0001] The invention relates to a method for estimating time delay of an underwater acoustic channel, in particular to a method for estimating time delay of an underwater acoustic channel based on orthogonal matching pursuit. Background technique [0002] In recent years, due to the high bandwidth utilization of Orthogonal Frequency Division Multiplexing (OFDM) technology and the low complexity of multipath channel equalization, it has been widely used in underwater acoustic communication systems. In practical applications, most OFDM systems use coherent receiver, which makes the accuracy of channel estimation very important. As a greedy algorithm with less computation, Orthogonal Matching Pursuit (OMP) becomes one of the most popular algorithms in the compressed sensing (CS) branch. In each iteration, the channel estimator based on the OMP algorithm first estimates the delay information of the channel, and then minimizes the fitting error by solving the lea...
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Login to View More IPC IPC(8): H04L25/02H04L27/26
CPCH04L25/0212H04L27/2695
Inventor 乔钢强夕竹马璐宋庆军
Owner HARBIN ENG UNIV