Uplink channel dynamic waveform switching

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) and a base station may support switching from one waveform to another on uplink channels. For example, a UE and a base station may utilize both frequency division multiplexing (SC-FDM) waveform and an orthogonal frequency division multiplexing (OFDM) waveforms based on channel conditions and other factors. In some examples, a UE may switch for some uplink channels, and use a single waveform for other channels. For example, switching waveforms for channels that utilize frequency domain code division multiplexing (CDM) channel may interrupt the orthogonality of multiplexed transmissions. A UE may transition from one waveform to another either autonomously or based on an explicit indication from a base station. If a UE switches autonomously, it may send an indication of the transition to the serving base station.

What is claimed is: 
     
         1 . An apparatus for wireless communications, comprising:
 a processor;   memory coupled with the processor; and   instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
 determine whether an uplink physical layer channel is configured for frequency domain code division multiplexing (CDM); 
 select a waveform switching mode based at least in part on the determination of whether the uplink physical layer channel is configured for frequency domain CDM; 
 identify a waveform for the uplink physical layer channel based at least in part on the waveform switching mode; and 
 communicate on the uplink physical layer channel using the identified waveform. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the waveform switching mode comprises a switching mode based at least in part on the determining, and the instructions are further operable, when executed by the processor, to cause the apparatus to:
 switch the waveform for the uplink physical layer channel based at least in part on the switching mode.   
     
     
         3 . The apparatus of  claim 1 , wherein the instructions are further operable, when executed by the processor, to cause the apparatus to:
 determine that the uplink physical layer channel is configured for frequency domain CDM, wherein the waveform switching mode comprises a non-switching mode; and   maintain the identified waveform for the uplink physical layer channel based at least in part on the non-switching mode.   
     
     
         4 . The apparatus of  claim 1 , wherein the uplink physical layer channel comprises a physical uplink shared channel (PUSCH). 
     
     
         5 . The apparatus of  claim 1 , wherein the waveform switching mode comprises one or more rules for selecting an orthogonal frequency division multiplexing (OFDM) waveform or a single carrier frequency division multiplexing (SC-FDM) waveform. 
     
     
         6 . A method for wireless communications, comprising:
 determining whether an uplink physical layer channel is configured for frequency domain code division multiplexing (CDM);   selecting a waveform switching mode based at least in part on the determination of whether the uplink physical layer channel is configured for frequency domain CDM;   identifying a waveform for the uplink physical layer channel based at least in part on the waveform switching mode; and   communicating on the uplink physical layer channel using the identified waveform.   
     
     
         7 . The method of  claim 6 , wherein the waveform switching mode comprises a switching mode based at least in part on the determining, the method further comprising:
 switching the waveform for the uplink physical layer channel based at least in part on the switching mode.   
     
     
         8 . The method of  claim 6 , further comprising:
 determining that the uplink physical layer channel is configured for frequency domain CDM, wherein the waveform switching mode comprises a non-switching mode; and   maintaining the identified waveform for the uplink physical layer channel based at least in part on the non-switching mode.   
     
     
         9 . The method of  claim 6 , wherein the uplink physical layer channel comprises a physical uplink shared channel (PUSCH). 
     
     
         10 . The method of  claim 6 , wherein the waveform switching mode comprises one or more rules for selecting an orthogonal frequency division multiplexing (OFDM) waveform or a single carrier frequency division multiplexing (SC-FDM) waveform. 
     
     
         11 . An apparatus for wireless communications, comprising:
 means for determining whether an uplink physical layer channel is configured for frequency domain code division multiplexing (CDM);   means for selecting a waveform switching mode based at least in part on the determination of whether the uplink physical layer channel is configured for frequency domain CDM;   means for identifying a waveform for the uplink physical layer channel based at least in part on the waveform switching mode; and   means for communicating on the uplink physical layer channel using the identified waveform.   
     
     
         12 . The apparatus of  claim 11 , wherein the waveform switching mode comprises a switching mode based at least in part on the determining, the apparatus further comprising:
 means for switching the waveform for the uplink physical layer channel based at least in part on the switching mode.   
     
     
         13 . The apparatus of  claim 11 , further comprising:
 means for determining that the uplink physical layer channel is configured for frequency domain CDM, wherein the waveform switching mode comprises a non-switching mode; and   means for maintaining the identified waveform for the uplink physical layer channel based at least in part on the non-switching mode.   
     
     
         14 . The apparatus of  claim 11 , wherein the uplink physical layer channel comprises a physical uplink shared channel (PUSCH). 
     
     
         15 . The apparatus of  claim 11 , wherein the waveform switching mode comprises one or more rules for selecting an orthogonal frequency division multiplexing (OFDM) waveform or a single carrier frequency division multiplexing (SC-FDM) waveform. 
     
     
         16 . A non-transitory computer-readable medium storing code for wireless communications, the code comprising instructions executable by a processor to:
 determine whether an uplink physical layer channel is configured for frequency domain code division multiplexing (CDM);   select a waveform switching mode based at least in part on the determination of whether the uplink physical layer channel is configured for frequency domain CDM;   identify a waveform for the uplink physical layer channel based at least in part on the waveform switching mode; and   communicate on the uplink physical layer channel using the identified waveform.   
     
     
         17 . The non-transitory computer-readable medium of  claim 16 , wherein the waveform switching mode comprises a switching mode based at least in part on the determining, and the instructions are further executable by the processor to:
 switch the waveform for the uplink physical layer channel based at least in part on the switching mode.   
     
     
         18 . The non-transitory computer-readable medium of  claim 16 , wherein the instructions are further executable by the processor to:
 determine that the uplink physical layer channel is configured for frequency domain CDM, wherein the waveform switching mode comprises a non-switching mode; and   maintain the identified waveform for the uplink physical layer channel based at least in part on the non-switching mode.   
     
     
         19 . The non-transitory computer-readable medium of  claim 16 , wherein the uplink physical layer channel comprises a physical uplink shared channel (PUSCH). 
     
     
         20 . The non-transitory computer-readable medium of  claim 16 , wherein the waveform switching mode comprises one or more rules for selecting an orthogonal frequency division multiplexing (OFDM) waveform or a single carrier frequency division multiplexing (SC-FDM) waveform.