Communication device

Abstract

An apparatus generating a packet of signals, a number of preamble signals of a preamble portion for each of a number of radio transmission units, and a number of data signals of a data portion, wherein a phase rotation in frequency domain is equal to a time shift in time domain is applied to each symbol of the number of preamble signals separately, the same phase rotation is applied to each symbol separately, the amount of the phase rotation is different for each preamble signal and each data signal, the amount of the phase rotation of one of the number of data signals and one of the number of preamble signals is both zero, and the amount of the phase rotation is equal between one of the preamble signals and one of the data signals for the same radio transmission unit.

1 . A method comprising:
 generating a packet of Orthogonal Frequency-Division Multiplexing (OFDM) signals for transmitting a plurality of data streams by use of a plurality of antennas, wherein the packet comprises a preamble portion and a data portion;   generating a number of preamble signals of the preamble portion from a predetermined signal for each of a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas, wherein   a phase rotation in frequency domain is equal to a time shift in time domain is applied to each OFDM symbol of the number of preamble signals separately,   the amount of the phase rotation is different for each preamble signal of said number of preamble signals, and   the amount of the phase rotation of one of the number of preamble signals is zero;   generating a number of data signals of the data portion from the plurality of data streams, wherein   the same phase rotation is applied to each OFDM symbol of the number of data signals separately,   the amount of the phase rotation is different for each data signal of said number of data signals,   the amount of the phase rotation of one of the number of data signals is zero, and   the amount of the phase rotation is equal between one of the preamble signals and one of the data signals for the same radio transmission unit of the number of radio transmission units.   
     
     
         2 . The method according to  claim 1 , wherein
 a guard interval is attached for each OFDM symbol of the preamble signal of the preamble portion and the plurality of data signals of the data portion.   
     
     
         3 . The method according to  claim 2 , further comprising:
 setting an amount to the phase rotation amount in which the amount of the time shift for each of the time shift for each of the plurality of data streams, wherein   the difference between the maximum amount of the amount for the plurality of data streams and the minimum amount is the length of the guard interval or less.   
     
     
         4 . The method according to  claim 3 , wherein
 the difference is half of the length of the guard interval, in a case that the number of the plurality of data streams is two.   
     
     
         5 . The method according to  claim 3 , wherein
 every difference between two adjacent amounts of amounts for the plurality of data streams is a constant and the same.   
     
     
         6 . The method according to  claim 1 , further comprising:
 determining a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas.   
     
     
         7 . A non-transitory computer-readable medium comprising computer-executable instructions for causing one or more processor(s) and/or memory to perform the method according to  claim 1 . 
     
     
         8 . A communication apparatus comprising:
 a generating circuit configured to:
 generate a packet of Orthogonal Frequency-Division Multiplexing (OFDM) signals for transmitting a plurality of data streams by use of a plurality of antennas, wherein the packet comprises a preamble portion and a data portion; 
 generate a number of preamble signals of the preamble portion from a predetermined signal for each of a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas, wherein 
   a phase rotation in frequency domain is equal to a time shift in time domain is applied to each OFDM symbol of the number of preamble signals separately,   the amount of the phase rotation is different for each preamble signal of said number of preamble signals,   the amount of the phase rotation of one of the number of preamble signals is zero,   the generating circuit is further configured to generate a number of data signals of the data portion from the plurality of data streams,   the same phase rotation is applied to each OFDM symbol of the number of data signals separately,   the amount of the phase rotation is different for each data signal of said number of data signals,   the amount of the phase rotation of one of the number of data signals is zero, and   the amount of the phase rotation is equal between one of the preamble signals and one of the data signals for the same radio transmission unit of the number of radio transmission units.   
     
     
         9 . The communication apparatus according to  claim 8 , wherein
 a guard interval is attached for each OFDM symbol of the preamble signal of the preamble portion and the plurality of data signals of the data portion.   
     
     
         10 . The communication apparatus according to  claim 9 , wherein
 the generating circuit is further configured to set an amount to the phase rotation amount in which the amount of the time shift for each of the time shift for each of the plurality of data streams, wherein   the difference between the maximum amount of the amount for the plurality of data streams and the minimum amount is the length of the guard interval or less.   
     
     
         11 . The communication apparatus according to  claim 10 , wherein
 the difference is half of the length of the guard interval, in a case that the number of the plurality of data streams is two.   
     
     
         12 . The communication apparatus according to  claim 10 , wherein
 every difference between two adjacent amounts of amounts for the plurality of data streams is a constant and the same.   
     
     
         13 . The communication apparatus according to  claim 8 , wherein
 the generating circuit is further configured to determine a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas.   
     
     
         14 . The communication apparatus according to  claim 8 , wherein
 said communication apparatus including one or more processor(s) and one or more memory device(s), wherein said one or more memory device(s) is configured to store instructions that, when executed by said one or more processor(s), cause said one or more processor(s) to be configured to function as said generating circuit.   
     
     
         15 . A method comprising:
 generating a packet of Orthogonal Frequency-Division Multiplexing (OFDM) signals for transmitting a plurality of data streams by use of a plurality of antennas, wherein the packet comprises a preamble portion and a data portion;   generating a number of preamble signals of the preamble portion from a predetermined signal for each of a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas, wherein   a time shift in time domain is equal to the phase rotation in frequency domain is applied to each OFDM symbol of the number of preamble signals separately,   the amount of the time shift is different for each preamble signal of said number of preamble signals, and   the amount of the time shift of one of the number of preamble signals is zero;   generating a number of data signals of the data portion from the plurality of data streams, wherein   the same time shift is applied to each OFDM symbol of the number of data signals separately,   the amount of the time shift is different for each data signal of said number of data signals,   the amount of the time shift of one of the number of data signals is zero, and   the amount of the time shift is equal between one of the preamble signals and one of the data signals for the same radio transmission unit of the number of radio transmission units.   
     
     
         16 . The method according to  claim 15 , wherein
 a guard interval is attached for each OFDM symbol of the preamble signal of the preamble portion and the plurality of data signals of the data portion.   
     
     
         17 . The method according to  claim 16 , further comprising:
 setting an amount to the time shift amount in which the amount of the phase rotation for each of the phase rotation for each of the plurality of data streams, wherein   the difference between the maximum amount of the amount for the plurality of data streams and the minimum amount is the length of the guard interval or less.   
     
     
         18 . The method according to  claim 17 , wherein
 the difference is half of the length of the guard interval, in a case that the number of the plurality of data streams is two.   
     
     
         19 . The method according to  claim 17 , wherein
 every difference between two adjacent amounts of amounts for the plurality of data streams is a constant and the same.   
     
     
         20 . The method according to  claim 15 , further comprising:
 determining a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas.   
     
     
         21 . A non-transitory computer-readable medium comprising computer-executable instructions for causing one or more processor(s) and/or memory to perform the method according to  claim 15 . 
     
     
         22 . A communication apparatus comprising:
 a generating circuit configured to:
 generate a packet of Orthogonal Frequency-Division Multiplexing (OFDM) signals for transmitting a plurality of data streams by use of a plurality of antennas, wherein the packet comprises a preamble portion and a data portion; 
 generate a number of preamble signals of the preamble portion from a predetermined signal for each of a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas, wherein 
   a time shift in time domain is equal to the phase rotation in frequency domain is applied to each OFDM symbol of the number of preamble signals separately,   the amount of the time shift is different for each preamble signal of said number of preamble signals,   the amount of the time shift of one of the number of preamble signals is zero,   the generating circuit is further configured to generate a number of data signals of the data portion from the plurality of data streams,   the same time shift is applied to each OFDM symbol of the number of data signals separately,   the amount of the time shift is different for each data signal of said number of data signals,   the amount of the time shift of one of the number of data signals is zero, and   the amount of the time shift is equal between one of the preamble signals and one of the data signals for the same radio transmission unit of the number of radio transmission units.   
     
     
         23 . The communication apparatus according to  claim 22 , wherein
 a guard interval is attached for each OFDM symbol of the preamble signal of the preamble portion and the plurality of data signals of the data portion.   
     
     
         24 . The communication apparatus according to  claim 23 , wherein
 the generating circuit is further configured to set an amount to the time shift amount in which the amount of the phase rotation for each of the phase rotation for each of the plurality of data streams, wherein   the difference between the maximum amount of the amount for the plurality of data streams and the minimum amount is the length of the guard interval or less.   
     
     
         25 . The communication apparatus according to  claim 24 , wherein
 the difference is half of the length of the guard interval, in a case that the number of the plurality of data streams is two.   
     
     
         26 . The communication apparatus according to  claim 24 , wherein
 every difference between two adjacent amounts of amounts for the plurality of data streams is a constant and the same.   
     
     
         27 . The communication apparatus according to  claim 22 , wherein
 the generating circuit is further configured to determine a number of radio transmission units to be used for transmitting the packet by use of the plurality of antennas.   
     
     
         28 . The communication apparatus according to  claim 22 , wherein
 said communication apparatus including one or more processor(s) and one or more memory device(s), wherein said one or more memory device(s) is configured to store instructions that, when executed by said one or more processor(s), cause said one or more processor(s) to be configured to function as said generating circuit.