Method and apparatus for communication with shortened signal formats
Techniques for addressing high interference observed by a receiver in a wireless communication system are disclosed. The receiver may observe different interference power levels across a transmission symbol. In an aspect, the receiver applies different weights to different portions of the transmission symbol to account for fluctuation of interference power across the transmission symbol. In another aspect, a transmitter may send a transmission symbol such that a receiver can ignore a portion of a symbol period with high interference. In one design, the transmitter generates a transmission symbol including at least two copies of a signal component. The transmitter transmits at least one copy of the signal component in a portion of the symbol period in which the receiver does not observe high interference. The receiver processes the at least one copy of the signal component to recover data sent in the transmission symbol.
1. A method for wireless communication, comprising:
receiving information indicative of a receiver observing interference in a portion of a symbol period;
generating a transmission symbol including a cyclic prefix and at least two copies of a signal component based on the information indicative of the receiver observing interference; and
transmitting at least one copy of the signal component of the transmission symbol in the symbol period, the at least one copy of the signal component being non-overlapping with the interference observed by the receiver.
2. The method of claim 1 , wherein the generating the transmission symbol includes:
mapping modulation symbols to evenly spaced subcarriers;
mapping zero symbols to remaining subcarriers; and
generating the transmission symbol based on the mapped modulation symbols and the mapped zero symbols.
3. The method of claim 1 , wherein the generating the transmission symbol includes mapping modulation symbols to subcarriers with even-number indices or subcarriers with odd-number indices to generate the transmission symbol including two copies of the signal component.
4. The method of claim 1 , wherein the transmitting the at least one copy of the signal component includes transmitting all copies of the signal component of the transmission symbol.
5. The method of claim 1 , wherein the transmitting the at least one copy of the signal component includes transmitting only a single copy of the signal component of the transmission symbol.
6. The method of claim 1 , further including sending signaling indicative of the transmission symbol including at least two copies of the signal component.
7. The method of claim 1 , wherein the generating the transmission symbol includes generating the transmission symbol occupying a set of evenly spaced subcarriers in a first part of system bandwidth, wherein at least one guard band separates the first part of the system bandwidth from at least one other part of the system bandwidth in which transmission symbols occupy contiguous subcarriers.
8. The method of claim 1 , wherein the transmission symbol includes one of an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol, and a Code Division Multiple Access (CDMA) symbol.
9. An apparatus for wireless communication, comprising:
means for receiving information indicative of a receiver observing interference in a portion of a symbol period;
means for generating a transmission symbol including a cyclic prefix and at least two copies of a signal component based on the information indicative of the receiver observing interference; and
means for transmitting at least one copy of the signal component of the transmission symbol in the symbol period, the at least one copy of the signal component being non-overlapping with the interference observed by the receiver.
10. The apparatus of claim 9 , wherein the means for generating the transmission symbol includes:
means for mapping modulation symbols to evenly spaced subcarriers;
means for mapping zero symbols to remaining subcarriers; and
means for generating the transmission symbol based on the mapped modulation symbols and the mapped zero symbols.
11. The apparatus of claim 9 , further including means for sending signaling indicative of the transmission symbol including at least two copies of the signal component.
12. An apparatus for wireless communication, comprising:
at least one processor configured to receive information indicative of a receiver observing interference in a portion of a symbol period, to generate a transmission symbol including a cyclic prefix and at least two copies of a signal component based on the information indicative of the receiver observing interference, and to transmit at least one copy of the signal component of the transmission symbol in the symbol period, the at least one copy of the signal component being non-overlapping with the interference observed by the receiver.
13. The apparatus of claim 12 , wherein the at least one processor is configured to map modulation symbols to evenly spaced subcarriers, to map zero symbols to remaining subcarriers, and to generate the transmission symbol based on the mapped modulation symbols and the mapped zero symbols.
14. The apparatus of claim 12 , wherein the at least one processor is configured to send signaling indicative of the transmission symbol including at least two copies of the signal component.
15. A computer program product comprising a non-transitory computer-readable storage medium, the non-transitory computer-readable storage medium comprising:
instructions for causing at least one processor to receive information indicative of a receiver observing interference in a portion of a symbol period;
instructions for causing the at least one processor to generate a transmission symbol including a cyclic prefix and at least two copies of a signal component based on the information indicative of the receiver observing interference; and
instructions for causing the at least one processor to transmit at least one copy of the signal component of the transmission symbol in the symbol period, the at least one copy of the signal component being non-overlapping with the interference observed by the receiver.
16. A method for wireless communication, comprising:
receiving, at a receiver, a transmission symbol comprising a cyclic prefix, a first copy of a signal component, and a second copy of the signal component;
combining a selected portion of the first copy of the signal component with a corresponding portion of the second copy of the signal component, wherein the receiver obtains the selected portion of the first copy by discarding a portion of the first copy of the signal component that overlaps with an interfering signal observed by the receiver; and
recovering, based at least on the combined portions, data sent in the transmission symbol.
17. The method of claim 16 , wherein the obtaining the selected portion of the first copy of the signal component by discarding a portion of the first copy of the signal component that overlaps with an interfering signal further comprises discarding the cyclic prefix of the transmission symbol.
18. The method of claim 16 , further comprising:
identifying the interfering signal observed by the receiver.
19. The method of claim 16 , further comprising:
sending, to a transmitter of the transmission symbol, information indicative of the receiver observing the interfering signal in a portion of a symbol period.
20. The method of claim 16 , further comprising:
receiving signaling indicative of the transmission symbol including at least two copies of the signal component.
21. The method of claim 16 , wherein the transmission symbol includes one of an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol, and a Code Division Multiple Access (CDMA) symbol.
22. An apparatus for wireless communication, comprising:
means for receiving a transmission symbol comprising a cyclic prefix, a first copy of a signal component, and a second copy of the signal component;
means for combining a selected portion of the first copy of the signal component with a corresponding portion of the second copy of the signal component, wherein the means for receiving obtains the selected portion of the first copy by discarding a portion of the first copy of the signal component that overlaps with an interfering signal observed by the means for receiving; and
means for recovering, based at least on the combined portions, data sent in the transmission symbol.
23. The apparatus of claim 22 , further comprising:
means for sending, to a transmitter of the transmission symbol, information indicative of the receiver observing the interfering signal in a portion of a symbol period.
24. The apparatus of claim 22 , further comprising:
means for receiving signaling indicative of the transmission symbol including at least two copies of the signal component.
25. An apparatus for wireless communication, comprising:
at least one processor configured to receive a transmission symbol comprising a cyclic prefix, a first copy of a signal component, and a second copy of the signal component, to combine a selected portion of the first copy of the signal component with a corresponding portion of the second copy of the signal component, wherein the selected portion of the first copy is obtained by discarding a portion of the first copy of the signal component that overlaps with an observed interfering signal, and to recover, based at least on the combined portions, data sent in the transmission symbol.
26. The apparatus of claim 25 , wherein the at least one processor is configured to send, to a transmitter of the transmission symbol, information indicative of the receiver observing the interfering signal in a portion of a symbol period.
27. The apparatus of claim 25 , wherein the at least one processor is configured to receive signaling indicative of the transmission symbol including at least two copies of the signal component.