Apparatus and methods for providing efficient space-time structures for preambles, pilots and data for multi-input, multi-output communications systems

Abstract

Apparatus and methods for providing efficient space-time structures for preambles, pilots and data for multi-input, multi-output (MIMO) communications systems are provided. One such embodiment includes providing a computer program that includes logic configured to provide an initial structure. The computer program further includes logic configured to verify that the rows of the initial structure are linearly independent and logic configured to apply an orthonormalization procedure to the initial structure to obtain a space-time structure. Methods are also provided for providing efficient space-time structures for preambles, pilots and data for MIMO communications systems.

We claim: 
     
       1. A computer program embodied in a non-transitory computer-readable storage medium having a computer program stored thereon for providing efficient a space-time structures structure for preambles, pilots, and data for a multi-input, multi-output communications systems system, the computer program comprising:
 logic configured to provide an initial structure; 
 logic configured to verify that rows of said the initial structure are linearly independent; 
 logic configured to apply an orthonormalization procedure to said the initial structure to obtain a space-time structure for a preamble structure, a pilot structure, or pilot a data structure in a time or frequency domain; and 
 logic configured to insert apply the space-time structure as a space-time preamble structure, a space-time pilot structure, or pilot a space-time data structure in the time or frequency domain and combine the space-time preamble structure, the space-time pilot structure, or the space-time data structure with one or more data symbols for transmission in the multi-input, multi-output (MIMO) communications system. 
 
     
     
       2. The computer program computer-readable storage medium of  claim 1 , wherein said logic configured to provide an initial structure comprises:
 logic configured to choose a symbol alphabet to provide symbols for said the initial structure; and 
 logic configured to choose an initial configuration of said the initial structure. 
 
     
     
       3. The computer program computer-readable storage medium of  claim 1 , further comprising:
 logic configured to confirm that symbols of said the space-time structure are within a predetermined distance of symbols of said the initial structure; 
 logic configured to construct a space-time sequence structure from a plurality of said the space-time structures; and 
 logic configured to verify that a peak-to-average power ratio (PAPR) of said the space-time structure is less than a predetermined value. 
 
     
     
       4. The computer program computer-readable storage medium of  claim 3 , wherein said logic configured to confirm chat that the symbols of said the space-time structure are within a predetermined distance of the symbols of said the initial structure comprises logic configured to apply a Euclidean distance metric to determine the distance between the symbols of said the space-time structure and the symbols of said the initial structure. 
     
     
       5. The computer program computer-readable storage medium of  claim 1 , wherein said logic configured to verify that the rows of said the initial structure are linearly independent comprises logic configured to determine rank of said the initial structure. 
     
     
       6. The computer program computer-readable storage medium of  claim 1 , wherein said logic configured to apply an orthonormalization procedure to said the initial structure to obtain a space-time structure comprises logic configured to apply a row-wise Gram-Schmidt procedure to said the initial structure to obtain a the space-time structure. 
     
     
       7. The computer-readable storage medium of claim 1, wherein said logic configured to verify comprises logic configured to determine if a rank of the initial structure is equal to a number of associated transmit antennas. 
     
     
       8. The computer-readable storage medium of claim 1, wherein the space-time structure has properties of a unitary signal transmission matrix. 
     
     
       9. The computer-readable storage medium of claim 3, further comprising logic configured to store the space-time structure in a memory of the MIMO communications system if the symbols of the space-time structure are within the predetermined distance of the initial structure. 
     
     
       10. The computer-readable storage medium of claim 3, wherein said logic configured to verify that a PAPR of the space-time structure is less than a predetermined value comprises logic configured to convert the space-time structure to a time domain and calculate the PAPR of resultant signal samples. 
     
     
       11. The computer-readable storage medium of claim 3, further comprising logic configured to store the space-time preamble structure, the space-time pilot structure, or the space-time data structure in an encoder. 
     
     
       12. A method of providing a space-time structure for preambles, pilots, and data for a multi-input, multi-output communications system, the method comprising:
 verifying that rows of an initial structure are linearly independent;   applying an orthonormalization procedure to the initial structure at an encoder to obtain the space-time structure for a preamble structure, a pilot structure, or a data structure in a time or frequency domain; and   applying, at the encoder, the space-time structure as a space-time preamble structure, a space-time pilot structure, or a space-time data structure in the time or frequency domain and combining the space-time preamble structure, the space-time pilot structure, or the space-time data structure with one or more data symbols for transmission in the multi-input, multi-output communications system.   
     
     
       13. The method of claim 12, further comprising choosing a symbol alphabet to provide symbols for the initial structure and choosing an initial configuration of the initial structure. 
     
     
       14. The method of claim 12, further comprising:
 confirming that symbols of the space-time structure are within a predetermined distance of symbols of the initial structure; and   constructing a space-time sequence structure from a plurality of the space-time structures.   
     
     
       15. The method of claim 14, wherein said confirming comprises applying a Euclidean distance metric to determine the distance between the symbols of the space-time structure and the symbols of the initial structure. 
     
     
       16. The method of claim 14, further comprising storing the space-time structure in a memory of the MIMO communications system if the symbols of the space-time structure are within the predetermined distance of the initial structure. 
     
     
       17. The method of claim 12, further comprising verifying that a peak-to-averagc power ratio (PAPR) of the space-time structure is less than a predetermined value. 
     
     
       18. The method of claim 17, wherein said verifying comprises converting the space-time structure to a time domain and calculating the PAPR of resultant signal samples. 
     
     
       19. The method of claim 12, wherein said verifying that the rows of the initial structure are linearly independent comprises determining rank of the initial structure. 
     
     
       20. The method of claim 12, wherein said applying an orthonormalization procedure comprises applying a row-wise Gram-Schmidt procedure to the initial structure to obtain the space-time structure. 
     
     
       21. The method of claim 12, wherein said verifying comprises determining if a rank of the initial structure is equal to a number of associated transmit antennas. 
     
     
       22. The method of claim 12, wherein the space-time structure has properties of a unitary signal transmission matrix. 
     
     
       23. The method of claim 12, further comprising storing the space-time preamble structure, the space-time pilot structure, or the space-time data structure in an encoder. 
     
     
       24. A communication system comprising:
 an encoder having a pilot/training symbol inserter, the pilot/training symbol inserter configured to insert pilot symbols or training symbols into data blocks, wherein the inserted pilot symbols or training symbols include a space-time structure formed using an orthonormalization procedure, wherein the encoder is configured to:
 verify that rows of an initial structure are linearly independent; and 
 apply the orthonormalization procedure to the initial structure to form the space-time structure; 
   at least one modulator coupled to the encoder, each modulator outputting a frame structure comprising a data structure and at least a preamble structure or a pilot structure; and   at least one transmit antenna, each transmit antenna corresponding to a respective one of the at least one modulator, each transmit antenna transmitting the frame structure output from the corresponding modulator.   
     
     
       25. The communication system of claim 24, wherein the encoder is further configured to choose a symbol alphabet to provide symbols for the initial structure and choose an initial configuration of the initial structure. 
     
     
       26. The communication system of claim 24, wherein the encoder is further configured to:
 confirm that symbols of the space-time structure are within a predetermined distance of symbols of the initial structure; and   construct a space-time sequence structure from a plurality of the space-time structures.   
     
     
       27. The communication system of claim 26, wherein the encoder is further configured to apply a Euclidean distance metric to determine the distance between the symbols of the space-time structure and the symbols of the initial structure. 
     
     
       28. The communication system of claim 26, further comprising a memory in which the space-time structure is stored if the symbols of the space-time structure are within the predetermined distance of the initial structure. 
     
     
       29. The communication system of claim 24, wherein the encoder is further configured to determine a rank of the initial structure. 
     
     
       30. The communication system of claim 24, wherein the encoder is further configured to apply a row-wise Gram-Schmidt procedure to the initial structure to obtain the space-time structure. 
     
     
       31. The communication system of claim 24, wherein the encoder is further configured to determine if a rank of the initial structure is equal to a number of associated transmit antennas. 
     
     
       32. The communication system of claim 24, wherein the encoder is further configured to verify that a peak-to-average power ratio of the space-time structure is less than a predetermined value. 
     
     
       33. The communication system of claim 32, wherein the encoder is further configured to convert the space-time structure to a time domain and calculate the PAPR of resultant signal samples. 
     
     
       34. The communication system of claim 24, wherein the space-time structure has properties of a unitary signal transmission matrix. 
     
     
       35. The communication system of claim 24, wherein the encoder is further configured to store the space-time preamble structure, the space-time pilot structure, or the space-time data structure.