Adaptive waveform selection in wireless communications
Systems and methods of wireless communication in which wireless devices are adapted to implement adaptive waveform selection are disclosed. For example, operation according to embodiments may provide for use of a waveform design that minimizes peak-to-average power ratio (PAPR), such as single-carrier frequency division multiplexing (SC-FDM), as well as a waveform design that provides higher spectral efficiency, such as orthogonal frequency division multiplexing (OFDM), for scenarios that are not power-limited and the higher PAPR is acceptable. Adaptive waveform selection may be based implicitly on one or more parameters or may be based on explicit signaling. Adaptive waveform selection may be utilized with respect to initially establishing a communication link and/or with respect to an established communication link.
1. A method for adaptive waveform selection for signal transmission in a wireless communication system, the method comprising:
analyzing, by a wireless device of the wireless communication system, at least one attribute of a wireless communication associated with a random access procedure, the at least one attribute including at least one of: system information present in a broadcast downlink message, information in a random access response message, a physical random access channel (PRACH) sequence used for initial access, and a measurement made by the wireless device; and
determining a waveform to use for at least one uplink random access message transmission associated with the random access procedure, wherein the determining is based on the analyzed at least one attribute, wherein the waveform is one from a plurality of waveforms for uplink signal transmissions, wherein the at least one uplink random access message includes a third message to be transmitted after receiving a random access response message, wherein the determining the waveform to use for the at least one uplink random access message transmission includes determining a waveform to use for the third message, and wherein the plurality of waveforms comprise a single-carrier frequency division multiplexing (SC-FDM) waveform design and an orthogonal frequency division multiplexing (OFDM) waveform design.
2. The method of claim 1 , further comprising:
analyzing, by the wireless device, a plurality of parameters of a wireless communication scheduling grant; and
selecting a waveform from the plurality of waveforms for uplink signal transmission based on a particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analyzing, wherein the selecting the waveform for uplink signal transmission includes selecting the waveform for uplink signal transmission without the wireless device having received explicit signaling of a waveform selection for data transmission.
3. The method of claim 2 , further comprising:
receiving the scheduling grant via a fixed waveform downlink control channel; and
selecting the waveform from the plurality of waveforms for uplink signal transmission using signaling of a waveform selection for data transmission included in the scheduling grant.
4. The method of claim 2 , further comprising:
selecting the waveform from the plurality of waveforms for uplink signal transmission using signaling of a waveform selection for data transmission included in the scheduling grant; and
providing the random access response message via a fixed waveform.
5. The method of claim 2 , wherein the plurality of parameters of the wireless communication scheduling grant includes at least one of a number of component carriers for the signal transmission, a modulation order used with respect to a component carrier, a number of spatial layers used with respect to the component carrier, or a spectral efficiency of the modulation-and-coding format with respect to a component carrier for the signal transmission as the one or more parameters of the wireless communication scheduling grant for selecting the waveform.
6. The method of claim 2 , wherein the plurality of waveforms comprise a single-carrier frequency division multiplexing (SC-FDM) waveform design and an orthogonal frequency division multiplexing (OFDM) waveform design, and further comprising:
selecting the OFDM waveform design when the particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analyzing is determined to at least meet a threshold value; and
selecting the SC-FDM waveform design when the particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analyzing is determined to be lower than a threshold value.
7. The method of claim 2 , further comprising:
comparing the particular combination of attributes for the plurality of grant parameters to waveform selection information using a mapping between grant parameters and waveforms of the plurality of waveforms.
8. The method of claim 7 , further comprising:
updating the mapping between grant parameters and waveforms of the plurality of waveforms using a signal in a system information message or in a configuration message.
9. The method of claim 2 , further comprising:
determining that a combination of the selected waveform and the particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant is invalid; and
rejecting the wireless communication scheduling grant.
10. The method of claim 1 , wherein the waveform used for the at least one uplink random access message transmission that is made after receiving a random access response message is fixed.
11. The method of claim 1 , further comprising:
processing a random access procedure receive message a plurality of times using different waveforms of the plurality of wave forms to identify a waveform used in the random access procedure.
12. An apparatus for adaptive waveform selection for signal transmission in a wireless communication system, the apparatus comprising:
at least one processor;
a memory coupled to the at least one processor; and
a communication interface coupled to the at least one processor, wherein the at least one processor is configured:
to analyze at least one attribute of a wireless communication associated with a random access procedure, the at least one attribute including at least one of: system information present in a broadcast downlink message, information in a random access response message, a physical random access channel (PRACH) sequence used for initial access, and a measurement made by the wireless device; and
to determine a waveform to use for at least one uplink random access message transmission associated with the random access procedure, wherein the determining is based on the analyzed at least one attribute, wherein the waveform is one from a plurality of waveforms for uplink signal transmissions, wherein the at least one uplink random access message includes a third message to be transmitted after receiving a random access response message, wherein the determining the waveform to use for the at least one uplink random access message transmission includes determining a waveform to use for the third message, and wherein the plurality of waveforms comprise a single-carrier frequency division multiplexing (SC-FDM) waveform design and an orthogonal frequency division multiplexing (OFDM) waveform design.
13. The apparatus of claim 12 , wherein the at least one processor is configured:
to analyze a plurality of parameters of a wireless communication scheduling grant; and
to select a waveform from the plurality of waveforms for uplink signal transmission based on a particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analyzing without the wireless device having received explicit signaling of a waveform selection for data transmission.
14. The apparatus of claim 13 , wherein the at least one processor is configured:
to receive the scheduling grant via a fixed waveform downlink control channel; and
to select the waveform from the plurality of waveforms for signal transmission using signaling of a waveform selection for data transmission included in the scheduling grant.
15. The apparatus of claim 13 , wherein the at least one processor is configured:
to select the waveform from the plurality of waveforms for uplink signal transmission using signaling of a waveform selection for data transmission included in the scheduling grant; and
to provide the random access response message via a fixed waveform.
16. The apparatus of claim 13 , wherein the plurality of parameters of the wireless communication scheduling grant includes at least one of a number of component carriers for the signal transmission, a modulation order used with respect to a component carrier, a number of spatial layers used with respect to the component carrier, and a spectral efficiency of the modulation-and-coding format with respect to a component carrier for the signal transmission as the one or more parameters of the wireless communication scheduling grant for selecting the waveform.
17. The apparatus of claim 13 , wherein the plurality of waveforms comprise a single-carrier frequency division multiplexing (SC-FDM) waveform design and an orthogonal frequency division multiplexing (OFDM) waveform design, and wherein the at least one processor is configured:
to select the OFDM waveform design when the particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analyzing is determined to at least meet a threshold value; and
to select the SC-FDM waveform design when the particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analyzing is determined to be lower than a threshold value.
18. The apparatus of claim 13 , wherein the at least one processor is configured:
to compare the particular combination of attributes for the plurality of grant parameters to waveform selection information using a mapping between grant parameters and waveforms of the plurality of waveforms.
19. The apparatus of claim 18 , wherein the at least one processor is configured:
to update the mapping between grant parameters and waveforms of the plurality of waveforms using a signal in a system information message or in a configuration message.
20. The apparatus of claim 12 , wherein the at least one processor is configured:
to determine that a combination of the selected waveform and the particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant is invalid; and
to reject the wireless communication scheduling grant.
21. The apparatus of claim 12 , wherein the waveform used for the at least one uplink random access message transmission that is made after receiving a random access response message is fixed.
22. The apparatus of claim 21 , wherein the at least one processor is configured:
to process a random access procedure receive message a plurality of times using different waveforms of the plurality of wave forms to identify a waveform used in the random access procedure.
23. A non-transitory computer-readable medium having program code recorded thereon for adaptive waveform selection for signal transmission in a wireless communication system, the program code comprising:
program code for causing one or more computers to:
analyze at least one attribute of a wireless communication associated with a random access procedure, the at least one attribute including at least one of: system information present in a broadcast downlink message, information in a random access response message, a physical random access channel (PRACH) sequence used for initial access, and a measurement made by the wireless device; and
determine a waveform to use for at least one uplink random access message transmission associated with the random access procedure, wherein the determining is based on the analyzed at least one attribute, wherein the waveform is one from a plurality of waveforms for uplink signal transmissions, wherein the at least one uplink random access message includes a third message to be transmitted after receiving a random access response message, wherein the determining the waveform to use for the at least one uplink random access message transmission includes determining a waveform to use for the third message, and wherein the plurality of waveforms comprise a single-carrier frequency division multiplexing (SC-FDM) waveform design and an orthogonal frequency division multiplexing (OFDM) waveform design.
24. The non-transitory computer-readable medium of claim 23 , wherein the program code comprises program code for causing one or more computers to:
analyze a plurality of parameters of a wireless communication scheduling grant including at least one of a number of component carriers for the signal transmission, a modulation order used with respect to a component carrier, a number of spatial layers used with respect to the component carrier, and a spectral efficiency of the modulation-and-coding format with respect to a component carrier for the signal transmission.
25. The non-transitory computer-readable medium of claim 24 , wherein the program code comprises program code for causing one or more computers to:
select the OFDM design of the plurality of waveforms for uplink signal transmission when a particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analysis is determined to exceed a threshold; and
select the SC-FDM waveform design of the plurality of waveforms for uplink signal transmission when a particular combination of attributes for the plurality of grant parameters of the wireless communication scheduling grant identified by the analysis is determined to be less than the threshold.