Tail cancelation and addition of unique word for orthogonal frequency division multiplexing
Precoding, a symbol permutation operation, or pulse shaping may be used to suppress or cancel a tail or head of a symbol. Precoding may include utilization of a suppression vector. A unique word (UW) may be added to the suppression vector before spreading. The symbol and values of the suppression vector may be spread by a spreading function(s) and may be shaped prior to transmission.
1. A wireless transmit/receive unit (WTRU) comprising:
a processor configured to generate a first signal that utilizes a tail suppression signal generated at the WTRU from a data stream and utilizes a first unique word signal;
the processor further configured to map elements of the data stream and the first signal to one or more discrete Fourier transform spread (DFT-S) functions;
the processor further configured to perform an inverse DFT operation on symbols generated by the one or more DFT-S functions to generate a second signal; and
a transceiver configured to transmit the second signal.
2. The WTRU of claim 1 , wherein the symbols generated by the one or more DFT-S functions are shaped prior to the inverse DFT operation.
3. The WTRU of claim 1 , wherein a second unique word signal is added to the second signal prior to the transmission.
4. The WTRU of claim 3 , wherein the first unique word signal or the second unique word signal is based on the data stream.
5. The WTRU of claim 3 , wherein the first unique word signal is associated with a length based on an estimated channel impulse response.
6. The WTRU of claim 1 , wherein the one or more DFT-S functions comprise a first group of DFT-S functions and a second group of DFT-S functions and wherein the first signal is mapped to the first group of DFT-S functions.
7. The WTRU of claim 1 , wherein the tail suppression signal is based on a previous tail buffered by the WTRU.
8. A method performed by a wireless transmit/receive unit (WTRU), the method comprising:
generating, by the WTRU, a first signal utilizing a tail suppression signal generated at the WTRU from a data stream and utilizing a first unique word signal;
mapping, by the WTRU, elements of the data stream and the first signal to one or more discrete Fourier transform spread (DFT-S) functions;
performing, by the WTRU, an inverse DFT operation on symbols generated by the one or more DFT-S functions to generate a second signal; and
transmitting, by the WTRU, the second signal.
9. The method of claim 8 , wherein the symbols generated by the one or more DFT-S functions are shaped prior to the inverse DFT operation.
10. The method of claim 8 , wherein a second unique word signal is added to the second signal prior to the transmitting.
11. The method of claim 10 , wherein the first unique word signal or the second unique word signal is based on the data stream.
12. The method of claim 10 , wherein the first unique word signal is associated with a length based on an estimated channel impulse response.
13. The method of claim 8 , wherein the one or more DFT-S functions comprise a first group of DFT-S functions and a second group of DFT-S functions and wherein the first signal is mapped to the first group of DFT-S functions.
14. The method of claim 8 , wherein the tail suppression signal is based on a previous tail buffered by the WTRU.
15. A network device comprising:
a processor configured to generate a first signal that utilizes a tail suppression signal generated at the WTRU from a data stream and utilizes a first unique word signal;
the processor further configured to map elements of the data stream and the first signal to one or more discrete Fourier transform spread (DFT-S) functions;
the processor further configured to perform an inverse DFT operation on symbols generated by the one or more DFT-S functions to generate a second signal; and
a transceiver configured to transmit the second signal.
16. The network device of claim 15 , wherein the symbols generated by the one or more DFT-S functions are shaped prior to the inverse DFT operation.
17. The network device of claim 15 , wherein a second unique word signal is added to the second signal prior to the transmission.
18. The network device of claim 17 , wherein the first unique word signal or the second unique word signal is based on the data stream.
19. The network device of claim 17 , wherein the first unique word signal is associated with a length based on an estimated channel impulse response.
20. The network device of claim 15 , wherein the one or more DFT-S functions comprise a first group of DFT-S functions and a second group of DFT-S functions and wherein the first signal is mapped to the first group of DFT-S functions.