Methods of controlling communication parameters of wireless systems

Abstract

The present invention provides a method for controlling a communication parameter in a channel through which data is transmitted between a transmit unit with M transmit antennas and a receive unit with N receive antennas by selecting from among proposed mapping schemes an applied mapping scheme according to which the data is converted into symbols and assigned to transmit signals TS p , p=1 . . . M, which are transmitted from the M transmit antennas. The selection of the mapping scheme is based on a metric; in one embodiment the metric is a minimum Euclidean distance d min,rx of the symbols when received, in another embodiment the metric is a probability of error P(e) in the symbol when received. The method can be employed in communication systems using multi-antenna transmit and receive units of various types including wireless systems, e.g., cellular communication systems, using multiple access techniques such as TDMA, FDMA, CDMA and OFDMA.

1. A method of controlling a communication parameter of a channel for transmitting data between a transmit unit having a number M of transmit antennas and a receive unit having a number N of receive antennas, said method comprising:
 a) providing proposed mapping schemes for converting said data into symbols and assigning said data to transmit signals TS p , where p=1 . . . M, for transmission from said M transmit antennas;  
 b) obtaining a measurement of said channel at said receiver;  
 c) using said measurement to compute for each of said proposed mapping schemes a minimum Euclidean distance d min,vx  of said symbols when received; and  
 d) selecting an applied mapping scheme from said proposed mapping schemes based on said minimum Euclidean distance d min,vx , thereby controlling said communication parameter.  
 
     
     
       2. The method of  claim 1 , wherein said proposed mapping schemes comprise modulating said data in a constellation selected from the group consisting of PSK, QAM, GMSK, FSK, PAM, PPM, CAP, CPM. 
     
     
       3. The method of  claim 1 , wherein said proposed mapping schemes comprise coding said data at predetermined coding rates. 
     
     
       4. The method of  claim 1 , wherein said proposed mapping schemes comprise at least one method selected from the group consisting of diversity coding and spatial multiplexing. 
     
     
       5. The method of  claim 4 , wherein said at least one method comprises diversity coding of order k ranging from 1 to M. 
     
     
       6. The method of  claim 5 , wherein said diversity coding is selected from the techniques consisting of space-time block coding, transmit antenna selection, Equal Gain Combining, Maximum Ratio Combining and delay diversity coding. 
     
     
       7. The method of  claim 5 , wherein said proposed mapping scheme comprises a random assignment of said transmit signals TS p  to a number k of said M antennas. 
     
     
       8. The method of  claim 5 , wherein said proposed mapping scheme comprises an assignment of said transmit signals TS p  to a number k of said M antennas based on a required minimum Euclidean distance d min,required . 
     
     
       9. The method of  claim 8 , wherein said required minimum Euclidean distance d min,required  is related to a quality parameter of said data. 
     
     
       10. The method of  claim 4 , wherein said at least one method comprises spatial multiplexing of order k ranging from 1 to M. 
     
     
       11. The method of  claim 10 , wherein said spatial multiplexing comprises a random assignment of said transmit signals TS p  to a number k of said M antennas. 
     
     
       12. The method of  claim 10 , wherein said spatial multiplexing comprises an assignment of said transmit signals TS p  to a number k of said M antennas based on a required minimum Euclidean distance d min,required . 
     
     
       13. The method of  claim 12 , wherein said required minimum Euclidean distance d min,required  is related to a quality parameter of said data. 
     
     
       14. The method of  claim 10 , wherein said receive unit is selected from the group consisting of maximum likelihood receivers, zero forcing equalizer receivers, successive cancellation receivers and minimum mean square error receivers. 
     
     
       15. The method of  claim 1 , wherein a minimum Euclidean distance d min,tx  of said symbols when transmitted is stored in a database. 
     
     
       16. The method of  claim 15 , wherein said database is located in a unit selected from the group consisting of said transmit unit and said receive unit. 
     
     
       17. The method of  claim 1 , wherein said communication parameter is selected from the group consisting of data capacity, signal quality, spectral efficiency and throughput. 
     
     
       18. The method of  claim 1 , further comprising:
 a) determining a quality parameter of said data;  
 b) establishing a relation between said quality parameter and a required minimum Euclidean distance d min,required  necessary to satisfy said quality parameter.  
 
     
     
       19. The method of  claim 18 , wherein said quality parameter is selected from the group consisting of signal-to-interference noise ratio, signal-to-noise ratio, power level, level crossing rate, level crossing duration, bit error rate, symbol error rate, packet error rate, and error probability. 
     
     
       20. The method of  claim 1 , wherein said transmit unit and said receive unit operate in accordance with at least one multiple access technique selected from the group consisting of TDMA, FDMA, CDMA, OFDMA. 
     
     
       21. The method of  claim 20 , wherein said proposed mapping schemes comprise diversity coding selected from the group consisting of space-time block coding, transmit antenna selection, Equal Gain Combining, Maximum Ratio Combining and delay diversity coding. 
     
     
       22. A method of controlling a communication parameter of a channel for transmitting data between a transmit unit having a number M of transmit antennas and a receive unit having a number N of receive antennas, said method comprising:
 a) providing proposed mapping schemes for converting said data into symbols and assigning said data to transmit signals TS p , where p=1 . . . M, for transmission from said M transmit antennas;  
 b) obtaining a measurement of said channel at said receiver;  
 c) using said measurement to compute for each of said proposed mapping schemes a probability of error P(e) in said symbols when received; and  
 d) selecting an applied mapping scheme from said proposed mapping schemes based on said probability of error P(e), thereby controlling said communication parameter.  
 
     
     
       23. The method of  claim 22 , wherein said proposed mapping schemes comprise modulating said data in a constellation selected from the group consisting of PSK, QAM, GMSK, FSK, PAM, PPM, CAP, CPM. 
     
     
       24. The method of  claim 22 , wherein said proposed mapping schemes comprise coding said data at predetermined coding rates. 
     
     
       25. The method of  claim 22 , wherein said proposed mapping schemes comprise at least one method selected from the group consisting of diversity coding and spatial multiplexing. 
     
     
       26. The method of  claim 25 , wherein said at least one method comprises diversity coding of order k ranging from 1 to M. 
     
     
       27. The method of  claim 26 , wherein said diversity coding is selected from the techniques consisting of space-time block coding, transmit antenna selection, Equal Gain Combining, Maximum Ratio Combining and delay diversity coding. 
     
     
       28. The method of  claim 26 , wherein said proposed mapping scheme comprises a random assignment of said transmit signals TS p  to a number k of said M antennas. 
     
     
       29. The method of  claim 26 , wherein said proposed mapping scheme comprises an assignment of said transmit signals TS p  to a number k of said M antennas based on a required probability of error P(e) req . 
     
     
       30. The method of  claim 25 , wherein said at least one method comprises spatial multiplexing of order k ranging from 1 to M. 
     
     
       31. The method of  claim 30 , wherein said spatial multiplexing comprises a random assignment of said transmit signals TS p  to a number k of said M antennas. 
     
     
       32. The method of  claim 30 , wherein said spatial multiplexing comprises an assignment of said transmit signals TS p  to a number k of said M antennas based on a required probability of error P(e) req . 
     
     
       33. The method of  claim 30 , wherein said receive unit is selected from the group consisting of maximum likelihood receivers, zero forcing equalizer receivers, successive cancellation receivers and minimum mean square error receivers. 
     
     
       34. The method of  claim 22 , wherein a minimum Euclidean distance d min,tx  of said symbols when transmitted is stored in a database. 
     
     
       35. The method of  claim 34 , wherein said database is located in a unit selected from the group consisting of said transmit unit and said receive unit. 
     
     
       36. The method of  claim 22 , wherein said communication parameter is selected from the group consisting of data capacity, signal quality, spectral efficiency and throughput. 
     
     
       37. The method of  claim 22 , wherein said transmit unit and said receive unit operate in accordance with at least one multiple access technique selected from the group consisting of TDMA, FDMA, CDMA, OFDMA. 
     
     
       38. The method of  claim 37 , wherein said proposed mapping schemes comprise diversity coding selected from the group consisting of space-time block coding, transmit antenna selection, Equal Gain Combining, Maximum Ratio Combining and delay diversity coding. 
     
     
       39. A communication system with a controlled communication parameter of a channel for transmitting data between a transmit unit having a number M of transmit antennas and a receive unit having a number N of receive antennas, said transmit unit having a mapping circuit comprising:
 a) a conversion unit for converting said data into symbols;  
 b) an assigning unit for assigning said data to transmit signals TS p , where p=1 . . . M, for transmission from said M transmit antennas, said converting and said assigning being in accordance with proposed mapping schemes;  
 
       said receive unit comprising:
 a) a channel estimator for obtaining a measurement of said channel;  
 b) a computing block for computing for each of said proposed mapping schemes a minimum Euclidean distance d min,rx  of said symbols when received; and  
 c) a selection block for selecting an applied mapping scheme from said proposed mapping schemes based on said minimum Euclidean distance d min,vx , thereby controlling said communication parameter.  
 
     
     
       40. The communication system of  claim 39 , wherein said assigning unit comprises a diversity coding block and a spatial multiplexing block. 
     
     
       41. The communication system of  claim 40 , wherein said diversity coding block comprises at least one block selected from the group consisting of a space-time coding block, a transmit antenna selection block, Equal Gain Channel coding block, Maximum Ratio Channel coding block and delay diversity coding block. 
     
     
       42. The communication system of  claim 40 , wherein said receive unit is selected from the group consisting of maximum likelihood receivers, zero forcing equalizer receivers, successive cancellation receivers and minimum mean square error receivers. 
     
     
       43. The communication system of  claim 39 , further comprising a database for storing a minimum Euclidean distance d min,tx  for said symbols when transmitted. 
     
     
       44. The communication system of  claim 39 , wherein said computing block is selected from the group consisting of blocks for computing data capacity, signal quality, spectral efficiency and throughput. 
     
     
       45. The communication system of  claim 44 , further comprising a quality parameter computation block for determining a quality parameter of said data, said quality parameter being selected from the group consisting of signal-to-interference noise ratio, signal-to-noise ratio, power level, level crossing rate, level crossing duration, bit error rate, symbol error rate, packet error rate, and error probability. 
     
     
       46. The communication system of  claim 45 , further comprising an assessment block for establishing a correlation between said quality parameter and a required minimum Euclidean distance d min,required . 
     
     
       47. The communication system of  claim 39 , said communication system operating in accordance with at least one multiple access technique selected from the group consisting of TDMA, FDMA, CDMA, OFDMA. 
     
     
       48. A communication system with a controlled communication parameter of a channel for transmitting data between a transmit unit having a number M of transmit antennas and a receive unit having a number N of receive antennas, said transmit unit having a mapping circuit comprising:
 a) a conversion unit for converting said data into symbols;  
 b) an assigning unit for assigning said data to transmit signals TS p , where p=1 . . . M, for transmission from said M transmit antennas, said converting and said assigning being in accordance with proposed mapping schemes;  
 
       said receive unit comprising:
 a) a channel estimator for obtaining a measurement of said channel;  
 b) a computing block for computing for each of said proposed mapping schemes a probability of error P(e) of said symbols when received; and  
 c) a selection block for selecting an applied mapping scheme from said proposed mapping schemes based on said probability of error P(e), thereby controlling said communication parameter.  
 
     
     
       49. The communication system of  claim 48 , wherein said assigning unit comprises a diversity coding block and a spatial multiplexing block. 
     
     
       50. The communication system of  claim 49 , wherein said receive unit is selected from the group consisting of maximum likelihood receivers, zero forcing equalizer receivers, successive cancellation receivers and minimum mean square error receivers. 
     
     
       51. The communication system of  claim 48 , wherein said diversity coding block comprises at least one block selected from the group consisting of a space-time coding block, a transmit antenna selection block, Equal Gain Channel coding block, Maximum Ratio Channel coding block and delay diversity coding block. 
     
     
       52. The communication system of  claim 48 , further comprising a database for storing a required probability of error P(e) req . 
     
     
       53. The communication system of  claim 48 , wherein said computing block is selected from the group consisting of blocks for computing data capacity, signal quality, spectral efficiency and throughput. 
     
     
       54. The communication system of  claim 53 , further comprising a quality parameter computation block for determining a quality parameter of said data, said quality parameter being selected from the group consisting of signal-to-interference noise ratio, signal-to-noise ratio, power level, level crossing rate, level crossing duration, bit error rate, symbol error rate, packet error rate, and error probability. 
     
     
       55. The communication system of  claim 48 , said communication system operating in accordance with at least one multiple access technique selected from the group consisting of TDMA, FDMA, CDMA, OFDMA. 
     
     
       56. A wireless communication device comprising:
   a channel estimator, responsive to one or more antennas, to receive a plurality of signals associated with a communication channel, and to obtain a measurement of the communication channel;        a processing element, responsive to the channel estimator, to compute for a plurality of proposed mapping schemes a minimum Euclidean distance between symbols of the received signal ( s )  based, at least in part, on the channel measurement; and        a selection block, responsive to at the processing element, to select a mapping scheme from the proposed mapping schemes based, at least in part, on the computed Euclidean distance with the  0 ommunieationohannel, wherein the selected mapping scheme denotes how content at a remote communications device is to be applied to one or more antenna ( s )  associated with the remote communications device, and wherein the wireless communication device is able to provide an indication of the selected mapping scheme to the remote communications device.     
     
     
       57. A wireless communication device according to  claim 56 , wherein the performance parameter is one or more of a measure of receive signal strength, a measure of interference, a signal- to - noise ratio  ( SNR ) , a signal - to - interference and noise ratio  ( SINR ) , a bit - error rate  ( BER ) , a packet - error rate  ( PER ). 
     
     
       58. A wireless communication device according to  claim 56 , wherein the channel estimator obtains a measurement of the channel coefficients matrix H characterizing the communication channel. 
     
     
       59. A wireless communication device according to  claim 58 , wherein selection block selects an applied mapping scheme for use by a remote transmitter of the communication channel from a plurality of potential mapping schemes based, at least in part, on the measurement of the channel coefficient matrix H. 
     
     
       60. A wireless communication device according to  claim 58 , further comprising:
   a local transmitter, responsive to the selection block, to provide the indication of the selected mapping scheme to the remote communication device for application to subsequent transmission via the communication channel.     
     
     
       61. A wireless communication device according to  claim 56 , wherein the proposed mapping schemes include one or more of modulating said data in a constellation selected from the group consisting of PSK, QAM, GMSK, FSK, PAM, PPM, CAP, CPM. 
     
     
       62. A wireless communication device according to  claim 56 , wherein the wireless communication device is a wireless station in a wireless network including one or more antenna( e )  through which downlink signals are received from remote wireless access point.   
     
     
       63. A wireless communication device according to  claim 56 , further comprising:
   a memory system to store content including executable content; and        one or more processor element ( s ) , coupled with the memory system, to selectively access and execute at least a subset of the stored content to implement one or more of the channel estimator, computing block and selection block.     
     
     
       64. A wireless communication device comprising:
   a channel estimator, responsive to one or more antennas, to receive a plurality of signals associated with a communication channel, and to obtain a measurement of the communication channel;        a processing element, responsive to the channel estimator, to compute for a plurality of proposed mapping schemes a probability of error of the received signal ( s ) ; and        a selection block, responsive to the processing element, to select a mapping scheme from the proposed mapping schemes based, at least in part, on the computed probability of error, wherein the selected mapping scheme denotes how content at a remote communications device is to be applied to one or more antenna ( s )  associated with the remote communications device, and wherein the wireless communication device is able to provide an indication of the selected mapping scheme to the remote communications device.     
     
     
       65. A wireless communication device according to  claim 64 , wherein the performance metric is one or more of a measure of receive signal strength, a measure of interference, a signal- to - noise ratio  ( SNR ) , a signal - to - interference and noise ratio  ( SINK ) , a bit - error rate  ( BER ) , a packet - error rate  ( PER ). 
     
     
       66. A wireless communication device according to  claim 64 , wherein the channel estimator obtains a measurement of the channel coefficients matrix H characterizing the communication channel. 
     
     
       67. A wireless communication device according to  claim 64 , further comprising:
   a local transmitter, responsive to the selection block, to communicate the select applied mapping scheme to a remote transmitter of the communication channel for application to subsequent via the communication channel.     
     
     
       68. A wireless communication device according to  claim 64 , wherein the proposed mapping schemes include one or more of modulating said data in a constellation selected from the group consisting of PSK, QAM, GMSK, FSK, PAM, PPM, CAP, CPM. 
     
     
       69. A wireless communication device according to  claim 64 , further comprising:
   a memory system to store content including executable content; and one or more processor element(s), coupled with the memory system, to selectively access and execute at least a subset of the stored content to implement one or more of the channel estimator, computing block and selection block.     
     
     
       70. A wireless communication device comprising:
   a conversion unit, to receive data for wireless transmission to a remote device and to convert the received data into symbols;        an assignment unit, responsive to the conversion unit, to assign the symbols to transmit signals TS   p    of the communication channel, where p=I . . . M, for transmission from M transmit antennas; and        a receive element, coupled with the conversion unit and the assignment unit, to receive an indication of a selected mapping scheme from a plurality of possible mapping schemes from a remote communication unit, wherein the conversion and assignment are performed in accordance with the select mapping scheme.     
     
     
       71. A wireless communication device according to  claim 70 , wherein the indication of the selected mapping scheme is received from a remote wireless communication device and is selected based, at least in part, on a minimum Euclidean distance of symbols in the received signals TS p   .   
     
     
       72. A wireless communication device according to  claim 70 , wherein the indication of the selected mapping scheme is received from a remote wireless communication device and is selected based, at least in part, on a probability of error of said symbols in the received signals TS p   .   
     
     
       73. A wireless communication device comprising:
   two or more omnidirectional antenna ( e )  through which signals associated with a communication channel are received;        a channel estimator, responsive to at least a subset of the antennas, to obtain a measurement of the received communication channel;        a processing element, responsive to the channel estimator, to compute for a plurality of proposed mapping schemes a minimum Euclidean distance between symbols of the received signal ( s )  based, at least in part, on the channel measurement; and        a selection block, responsive to estimator and the processing element, to select a mapping scheme from the proposed mapping schemes based, at least in part, on the computed minimum Euclidean distance to, wherein the selected mapping scheme denotes how content at a remote communications device is to be applied to one or more antenna ( s )  associated with the remote communications device, and wherein the wireless communication device is able to provide an indication of the selected mapping scheme to the remote communications device.     
     
     
       74. A communication device according to  claim 73 , comprising:
   a local transmitter, responsive to the selection block, to provide the indication of the selected mapping scheme to the remote communication device for application to subsequent transmission via the communication channel.     
     
     
       75. A wireless communication device according to  claim 74 , wherein the proposed mapping schemes include one or more of modulating said data in a constellation selected from the group consisting of PSK, QAM, GMSK, FSK, PAM, PPM, CAP, CPM. 
     
     
       76. A wireless communication device comprising:
   two or more omnidirectional antenna(e) through which signals associated with a communication channel are received;        a channel estimator, responsive to at least a subset of the antennas, to obtain a measurement of the received communication channel;        a processing element, responsive to the channel estimator, to compute for a plurality of proposed mapping schemes a probability of error of the symbols of the received signal(s); and        a selection block, responsive to and the processing element, to select a mapping scheme from the proposed mapping schemes based, at least in part, on the computed probability of error, wherein the selected mapping scheme denotes how content at a remote communications device is to be applied to one or more antenna(s) associated with the remote communications device, and wherein the wireless communication device is able to provide an indication of the selected mapping scheme to the remote communications device.     
     
     
       77. A communications device according to  claim 76 , further comprising:
   a local transmitter, responsive to the selection block, to communicate the select applied mapping scheme to a remote transmitter of the communication channel for application to subsequent transmission via the communication channel.     
     
     
       78. A wireless communication device according to  claim 76 , wherein the proposed mapping schemes include one or more of modulating said data in a constellation selected from the group consisting of PSK, QAM, GMSK, FSK, PAM, PPM, CAP, CPM.