Enabling digital beamforming techniques for RF systems having short repetitive synchronization sequences

A method for enabling digital beamforming (DBF) techniques within a system having a multi-element array antenna receiving RF signals from a plurality of sources transmitting on the same frequency at the same time in a noise environment, said RF signals having short repetitive synchronization sequences, said method of enabling DBF techniques, comprising the steps of:

• a) receiving repetitive synchronization RF signals from said plurality of sources utilizing a multi-element array antenna, each of said repetitive synchronization RF signals comprising an ideal known synchronization sequence, said ideal known synchronization sequence being denoted as ydi and a length of said ideal known synchronization sequence being denoted as Ndi, where i=0, 1, . . . m−1, and m is the total number of said plurality of sources;
• b) calculating a sequence of magnitudes and phases for each element of said multi-element array antenna corresponding to each of said ideal known synchronization sequences in said received synchronization RF signals, said sequence of said magnitudes and said phases comprising an array of N elements and being denoted as xi, wherein said phases are also referred to as absolute phases;
• c) calculating a relative phase for each element in said sequence of said magnitudes and said absolute phases by referencing said absolute phases of all elements in said array xi of N elements to a phase of a single element in said array xi of N elements;
• d) converting said array xi of N elements with said magnitudes and said absolute phases into an array of N elements with said magnitudes and said relative phases by replacing each of said absolute phases in said array xi of N elements with said calculated relative phase for each element, said array of N elements with said magnitudes and said relative phases being denoted as xri;
• e) calculating a relative cross correlation vector for each element of said multi-element array antenna utilizing said xri and said ydi, said relative cross correlation vector being denoted as rxdi, where rxdi=E{xriydi*} and * is a complex conjugate;
• and,
• f) generating a relative cross correlation vector estimate by filtering said rxdi, for use with DBF techniques.

A method for enabling digital beamforming (DBF) techniques within a system having a multi-element array antenna receiving RF signals in a noise environment, said system being a frequency hopped system with a relatively large hop range compared to a carrier frequency, said RF signals having short repetitive synchronization sequences, said method of enabling DBF techniques, comprising the steps of:

• a) receiving repetitive synchronization RF signals utilizing a multi-element array antenna, each of said repetitive synchronization RF signals comprising an ideal known synchronization sequence for each hopped frequency, said ideal known synchronization sequence for each of said hopped frequencies being denoted as ydj and a length of said ideal known synchronization sequence being denoted as Ndj, said hopped frequency being denoted as fj, where j=0, 1, . . . k−1 and k is the total number of hopped frequencies;
• b) calculating a sequence of magnitudes and phases for each element of said multi-element array antenna corresponding to each of said ideal known synchronization sequences for each of said hopped frequencies in said received synchronization RF signals, said sequence of said magnitudes and said phases comprising an array of N elements and being denoted as xj, wherein said phases are also referred to as absolute phases;
• c) compensating said phase of said array xj utilizing information regarding multi-element array geometry for each of said hopped frequencies;
• d) calculating a relative phase for each element in said sequence of said magnitudes and said absolute phases by referencing said absolute phases of all elements in said array xj of N elements to a phase of a single element in said array xj of N elements;
• e) converting said array xj of N elements with said magnitudes and said absolute phases into an array of N elements with said magnitudes and said relative phases by replacing each of said absolute phases in said array xj of N elements with said calculated relative phase for each element, said array of N elements with said magnitudes and said relative phases being denoted as xrj;
• f) calculating a relative cross correlation vector for each element of said multi-element array antenna utilizing said xrj and said ydj, said relative cross correlation vector being denoted as rxdj, where rxdj=E{xrjydj*} and * is a complex conjugate;
• g) translating said rxdj to a relative cross correlation vector corresponding to other hopped frequencies fi with said information regarding said multi-element array geometry, where i=0, 1, . . . k−1 and i≠j;
• and,
• h) generating a relative cross correlation vector estimate by filtering said rxdj, for use with DBF techniques.

An RF receiver for enabling digital beam forming (DBF) techniques receiving RF signals in a noise environment, said RF signals having short repetitive synchronization sequences, said RF receiver, comprising:

• at least one digital signal processor (DSP) for performing the following:
• a) calculating a sequence of magnitudes and phases for each element of said multi-element array antenna corresponding to each of said ideal known synchronization sequences in said received synchronization RF signals, said sequence of said magnitudes and said phases comprising an array of N elements and being denoted as x, wherein said phases are also referred to as absolute phases;
• b) calculating a relative phase for each element in said sequence of said magnitudes and said absolute phases by referencing said absolute phases of all elements in said array x of N elements to a phase of a single element in said array x of N elements;
• c) converting said array x of N elements with said magnitudes and said absolute phases into an array of N elements with said magnitudes and said relative phases by replacing each of said absolute phases in said array x of N elements with said calculated relative phase for each element, said array of N elements with said magnitudes and said relative phases being denoted as xr;
• d) calculating a relative cross correlation vector for each element of said multi-element array antenna utilizing said xr and said yd, said cross correlation vector being denoted as rxd, where rxd=E{xryd*} and * is a complex conjugate;
• and,
• e) generating a relative cross correlation vector estimate by filtering said rxd, for use with DBF techniques.

An RF system for receiving RF signals in a noise environment, said RF signals having short repetitive synchronization sequences, said RF system, comprising:

• a) a multi-element array antenna for receiving repetitive synchronization RF signals, each of said repetitive synchronization RF signals comprising an ideal known synchronization sequence, said ideal known synchronization sequence being denoted as yd and a length of said ideal known synchronization sequence being denoted as Nd;
• and,
• b) an RF receiver, comprising at least one DSP for performing the following:
• i. calculating a sequence of magnitudes and phases for each element of said multi-element array antenna corresponding to each of said ideal known synchronization sequences in said received synchronization RF signals, said sequence of said magnitudes and said phases comprising an array of N elements and being denoted as x, wherein said phases are also referred to as absolute phases;
• ii. calculating a relative phase for each element in said sequence of said magnitudes and said absolute phases by referencing said absolute phases of all elements in said array x of N elements to a phase of a single element in said array x of N elements;
• iii. converting said array x of N elements with said magnitudes and said absolute phases into an array of N elements with said magnitudes and said relative phases by replacing each of said absolute phases in said array x of N elements with said calculated relative phase for each element, said array of N elements with said magnitudes and said relative phases being denoted as xr;
• iv. calculating a relative cross correlation vector for each element of said multi-element array antenna utilizing said xr and said yd, said cross correlation vector being denoted as rxd, where rxd=E{xryd*} and * is a complex conjugate;
• and,
• v. generating a relative cross correlation vector estimate by filtering said rxd, for use with DBF techniques.