Asymmetric TDD in Flexible Use Spectrum

Abstract

Methods and apparatuses are described for allocating transmission and reception times arising over three time division duplex communication paths, where the transmission and reception times for each path are asynchronous with respect to each of the other paths, and wherein guard bands are utilized between disposing signal paths, where such paths overlap during a given time span.

1 . A method, comprising:
 sending a first time division duplex (TDD) signal via a first uplink portion of a first time division duplex (TDD) communication path;
 wherein the first TDD communication path arises over a first band; 
 wherein the first uplink portion arises over a first uplink period; 
   receiving a second signal via a first downlink portion of the first TDD communication path;   wherein the second downlink portion arises over a first downlink period;   wherein the first TDD communication path is disposed between and mutually exclusive of a second TDD communication path and a third TDD communication path;   wherein the second TDD communication path arises over a second band and includes a second uplink portion and a second downlink portion;   wherein the third TDD communication path arises over a third band and includes a third uplink portion and a third downlink portion;   wherein the first TDD communication path is asynchronous with each of the second TDD communication path and the third TDD communication;   wherein the second TDD communication path is asynchronous with the third TDD communication path; and   wherein the first band is disposed between and mutually exclusive of each of the second band and the third band;   wherein each of the first TDD communication path, the second TDD communication path and the third TDD communication path are configured to operate over a communication time (t 0 -t 4 ) spanning, in sequence, an initial time (t 0 ), a first time (t 1 ), a second time (t 2 ), and third time (t 3 ), and a fourth time (t 4 );   wherein for the first TDD communication path, the communication time is first allocated into a first TDD receive time slot and a first TDD transmit time slot;   wherein for the second TDD communication path, the communication time is second allocated into a second TDD receive time slot and a second TDD transmit time slot;   wherein the second TDD receive time slot begins with the first TDD receive time slot; and   wherein the second TDD transmit time slot ends with the first TDD transmit time slot.   
     
     
         2 . The method of  claim 1 ,
 wherein the first uplink portion is contiguous with only the third uplink portion; and   wherein the first down link portion is contiguous with only the second downlink portion.   
     
     
         3 . The method of  claim 2 ,
 wherein the first TDD receive time slot begins at substantially the initial time (t 0 ) and ends at substantially the second time (t 2 );   wherein the first TDD transmit time slot starts at substantially the second time (t 2 ) and ends at substantially the fourth time (t 4 );   wherein the second TDD receive time slot begins at substantially the initial time (t 0 ) and ends at substantially the third time (t 3 ).   
     
     
         4 . The method of  claim 3 ,
 wherein for the third TDD communication path, the communication time is third allocated into a third TDD receive time slot and a third TDD transmit time slot; and   wherein the third TDD receive time slot begins at substantially the initial time (t 0 ) and ends at substantially the first time (t 1 ).   
     
     
         5 . The method of  claim 4 ,
 wherein, during the first TDD transmit time slot, the first uplink portion is separated by an uplink guard band from both the second uplink portion and the second downlink portion; and   wherein, during the first TDD receive time slot, the first downlink portion is separated by a downlink guard band from both the third uplink portion and the third downlink portion.   
     
     
         6 . The method of  claim 2 ,
 for the second TDD communication path,
 wherein the second TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the third time (t 3 ), and 
 wherein the second TDD transmit time slot starts at substantially the third time (t 3 ) and ends at substantially the fourth time (t 4 ); and 
   for the third TDD communication path,
 wherein the third TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the first time (t 1 ), and 
 wherein the third TDD transmit time slot starts at substantially the first time (t 1 ) and ends at substantially the fourth time (t 4 ). 
   
     
     
         7 . The method of  claim 1 ,
 wherein the first uplink portion is contiguous with only the second uplink portion; and   wherein the first down link portion is contiguous with only the third downlink portion.   
     
     
         8 . The method of  claim 7 ,
 wherein the first TDD receive time slot begins at substantially the initial time (t 0 ) and ends at substantially the second time (t 2 );   wherein the first TDD transmit time slot starts at substantially the second time (t 2 ) and ends at substantially the fourth time (t 4 ); and   wherein the second TDD receive time slot begins at substantially the initial time (t 0 ) and ends at substantially the first time (t 1 ).   
     
     
         9 . The method of  claim 8 ,
 wherein for the third TDD communication path, the communication time is third allocated into a third TDD receive time slot and a third TDD transmit time slot;   wherein the third TDD receive time slot begins at substantially the initial time (t 0 ) and ends at substantially the third time (t 3 ).   
     
     
         10 . The method of  claim 9 ,
 wherein, during the first TDD transmit time slot, the first uplink portion is separated by an uplink guard band from both the third uplink portion and the third downlink portion; and   wherein, during the first TDD receive time slot, the first downlink portion is separated by a downlink guard band from both the second uplink portion and the second downlink portion.   
     
     
         11 . The method of  claim 7 ,
 wherein for the second TDD communication path,
 the second TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the first time (t 1 ); and 
 the second TDD transmit time slot starts at substantially the first time (t 1 ) and ends at substantially the fourth time (t 4 ). 
   
     
     
         12 . The method of  claim 11 ,
 wherein for the third TDD communication path,
 the third TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the third time (t 3 ); and 
 the third TDD transmit time slot starts at substantially the third time (t 3 ) and ends at substantially the fourth time (t 4 ). 
   
     
     
         13 . The method of  claim 1 , comprising:
 sending a third signal over the second uplink portion;   receiving a fourth signal over the second downlink portion;   wherein the first signal and second signal are communicated using a first communications system; and   wherein the third signal and fourth signal are communicated using a second communications system.   
     
     
         14 . An apparatus, comprising:
 a communications device configured to:
 send a first time division duplex (TDD) signal via a first uplink portion of a first time division duplex (TDD) communication path; and 
 receive a second signal via a first downlink portion of the first TDD communication path; 
   wherein the first uplink portion arises over a first uplink period;   wherein the second downlink portion arises over a first downlink period;   wherein the first TDD communication path is disposed between and mutually exclusive of a second TDD communication path and a third TDD communication path;
 wherein the second TDD communication path includes a second uplink portion and a second downlink portion; 
 wherein the third TDD communication path includes a third uplink portion and a third downlink portion; 
   wherein the first TDD communication path is asynchronous with each of the second TDD communication path and the third TDD communication; and   wherein the second TDD communication path is asynchronous with the third TDD communication path.   
     
     
         15 . The apparatus of  claim 14 ,
 wherein the first uplink portion is separated by an uplink guard band from the second uplink portion and the second downlink portion; and   wherein the first downlink portion is separated by a downlink guard band from the third uplink portion and the third downlink portion.   
     
     
         16 . The apparatus of  claim 14 ,
 wherein communication time for each of the first TDD communication path, second TDD communication path and third TDD communication path is allocated over a time span beginning at an initial time (t 0 ), spanning in order a first time (t 1 ), a second time (t 2 ), a third time (t 3 ), and ending at a fourth time (t 4 );   wherein for the first TDD communication path,
 a first TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the second time (t 2 ), 
   wherein for the second TDD communication path,
 a second TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the third time (t 3 ); and 
 a second TDD transmit time slot starts at substantially the third time (t 3 ) and ends at substantially the fourth time (t 4 ); and 
   wherein for the third TDD communication path,
 a third TDD receive time slot starts at substantially the initial time (t 0 ) and ends at substantially the first time (t 1 ); and 
 a third TDD transmit time slot starts at substantially the first time (t 1 ) and ends at substantially the fourth time (t 4 ); 
   wherein the communications device is further configured to:
 send a third signal over the second uplink portion; 
 receive a fourth signal over the second downlink portion; and 
   wherein the first signal and second signal are communicated using a first communications system; and
 wherein the third signal and fourth signal are communicated using a second communications system. 
   
     
     
         17 . An apparatus, comprising:
 a communications device configured to:
 send a first time division duplex (TDD) signal via a first uplink portion of a first time division duplex (TDD) communication path; 
 receive a second signal via a first downlink portion of the first TDD communication path; 
   wherein the first uplink portion arises over a first uplink period; and   wherein the second downlink portion arises over a first downlink period, wherein the first TDD communication path is disposed between and mutually exclusive of a second TDD communication path and a third TDD communication path;   wherein the second TDD communication path includes a second uplink portion and a second downlink portion;   wherein the third TDD communication path includes a third uplink portion and a third downlink portion;   wherein the first TDD communication path is asynchronous with each of the second TDD communication path and the third TDD communication;   wherein the second TDD communication path is asynchronous with the third TDD communication path;   wherein the first uplink portion is separated from and contiguous with the second uplink portion; and   the first down link portion is separated from and contiguous with the third downlink portion.   
     
     
         18 . The apparatus of  claim 17 ,
 wherein the communications device is configured to utilize one of the first TDD communication path, the second TDD communication path and the third TDD communication path   wherein each of the first, second and third TDD communication paths are operable over a communication time (t 0 -t 4 ) spanning, in sequence, an initial time (t 0 ), a first time (t 1 ), a second time (t 2 ), and third time (t 3 ), and a fourth time (t 4 );   wherein for the first TDD communication path, the communication time is first allocated into a first TDD receive time slot and a first TDD transmit time slot;
 wherein each of the first TDD receive time slot and the first TDD transmit time slot have equal durations; 
   wherein for the second TDD communication path, the communication time is second allocated into a second TDD receive time slot and a second TDD transmit time slot;   wherein for the third TDD communication path, the communication time is third allocated into a third TDD receive time slot and a third TDD transmit time slot; and   wherein the first TDD transmit time slot begins after the second TDD transmit time slot and before the third TDD transmit time slot.   
     
     
         19 . The apparatus of  claim 17 ,
 wherein a first time guard separates the first TDD receive time slot from the first TDD transmit time slot;   wherein the first uplink portion is separated from and contiguous with the second uplink portion;   wherein the first down link portion is separated from and contiguous with the third downlink portion;   wherein the first uplink portion is separated by an uplink guard band from each of the third uplink portion and, during a first overall period substantially starting at the second time (t 2 ) and substantially ending at the third time (t 3 ), the third downlink portion; and   wherein the first downlink portion is separated by a downlink guard band from each of the second downlink portion and, during a second overlap period substantially starting at the first time ( 1 ) and substantially ending at the second time (t 2 ), the second uplink portion.   
     
     
         20 . The apparatus of  claim 17 ,
 wherein for the second TDD communication path,
 a second TDD receive time slot is allocated to start at substantially an initial time (t 0 ) and end at substantially a first time (t 1 ), and 
 a second TDD transmit time slot is allocated to start at substantially the first time (t 1 ) and end at substantially a fourth time (t 4 ); and 
   wherein for the third TDD communication path,
 a third TDD receive time slot is allocated to start at substantially the initial time (t 0 ) and end at substantially a third time (t 3 ), and 
 a third TDD transmit time slot is allocated to start at substantially the third time (t 3 ) and end at substantially the fourth time (t 4 ); and 
 wherein for the first TDD communication path, a first TDD receive time slot and a first TDD receive time slot are equally allocated to start and end over a time period spanning the initial time (t 0 ) and the fourth time (t 4 ).