Maximal deversity combining interference cancellation using sub-array processors and respective delay elements

In a sidelobe canceler comprising:

• a main antenna;
• an array of sub-antennas;
• a subtractor having a first input connected to the main antenna and a second input;
• a main-array processor having a plurality of first weight multipliers for multiplying output signals of said sub-antennas with weight coefficients, a first weight controller for detecting correlations between the output signals of the sub-antennas and an output signal of said subtractor and deriving therefrom the weight coefficients of said first multipliers, and a first adder for summing output signals of said first multipliers to produce an output signal and supplying the output signal to the second input of the subtractor as an interference canceling signal;
• an adaptive matched filter for receiving the output signal of the subtractor and producing an output signal having a maximized signal-to-noise ratio;
• M sub-array processors each having a plurality of second multipliers for multiplying the output signals of said sub-antennas with weight coefficients, a second weight controller for detecting correlations between the output signals of the sub-antennas and a decision signal and deriving therefrom the weight coefficients of the second multipliers, and a second adder for summing output signals of the second multipliers to produce an output signal of each of the sub-array processors, a method comprising the steps of:
• a) combining the output signals of the M sub-array processors into a first diversity-combined signal;
• b) combining the first diversity-combined signal with the output signal of the matched filter to produce a second diversity-combined signal;
• c) removing intersymbol interference from the second diversity-combined signal according to a decision error to produce said decision signal and applying the decision signal to said sub-array processors;
• d) respectively introducing different amounts of delay to the output signals of (M-1) of the sub-array processors so that the output signal of the i-th sub-array processor is delayed by an amount equal to (i-1).tau., where i=2,3, . . . , M and .tau. is a predetermined delay time;
• and
• e) respectively introducing different amounts of delay to the decision signals applied to (M-1) of the sub-array processors so that the decision signal applied to the j-th sub-array processor is delayed by an amount equal to (M-j).tau., where j=1,2, . . . , M-1, wherein the total amounts of delay associated with each of the M sub-array processors is equal to (M-1).tau..

In a sidelobe canceler comprising:

• a main antenna;
• an array of sub-antennas;
• a subtractor having a first input connected to the main antenna and a second input;
• a main-array processor having a plurality of first weight multipliers for multiplying output signals of said sub-antennas with weight coefficients, a first weight controller for detecting correlations between the output signals of the sub-antennas and an output signal of said subtractor and deriving therefrom the weight coefficients of said first multipliers, and a first adder for summing output signals of said first multipliers to produce an output signal and supplying the output signal to the second input of the subtractor as an interference canceling signal;
• an adaptive matched filter for receiving the output signal of the subtractor and producing an output signal having a maximized signal-to-noise ratio;
• M sub-array processors each having a plurality of second multipliers for multiplying the output signals of said sub-antennas with weight coefficients, a second weight controller for detecting correlations between the output signals of the sub-antennas and a decision signal and deriving therefrom the weight coefficients of the second multipliers, and a second adder for summing output signals of the second multipliers to produce an output signal of each of the sub-array processors;
• and
• an adaptive equalizer for removing intersymbol interference according to a decision error to produce said decision signal and applying the decision signal to said sub-array processors, a method comprising the steps of:
• a) combining the output signals of the M sub-array processors into a first diversity-combined signal;
• b) transversal-filtering the frequency spectrum of the output signal of said main-array processor using the decision error of said adaptive equalizer according to a minimum means square error algorithm to produce a signal which is shaped to conform to an interfering signal introduced to said M sub-array processors;
• c) combining the signal produced by the step (b) with the first diversity combined signal to cancel said interfering signal introduced to said M sub-array processors;
• d) combining the interference-canceled first diversity-combined signal with the output signal of the matched filter to produce a second diversity-combined signal and applying the second diversity-combined signal to said adaptive equalizer to remove said intersymbol interference from the second diversity combined signal;
• e) respectively introducing different amounts of delay to the output signals of (M-1) of the sub-array processors so that the output signal of the i-th sub-array processor is delayed by an amount equal to (i-1).tau., where i=2,3, . . . , M and .tau. is a predetermined delay time;
• and
• f) respectively introducing different amounts of delay to the decision signals applied to (M-1) of the sub-array processors so that the decision signal applied to the j-th sub-array processor is delayed by an amount equal to (M-j).tau., where j=1,2, . . . , M-1, wherein the total amounts of delay associated with each of the M sub-array processors is equal to (M-1).tau..