Sounding reference signal transmissions in enhanced machine type communication

An apparatus for wireless communications, comprising:

• at least one processor;
• and
• memory coupled to the at least one processor, the memory storing instructions executable by the at least one processor to cause the apparatus to:
• determine one or more narrowband regions partitioned from wider system bandwidth for communicating with a network entity;
• determine time-frequency sounding reference signal (SRS) transmission resources, within the one or more narrowband regions of a first subframe, for transmitting SRSs, using at least one of:
• an SRS cyclic shift, wherein the SRS cyclic shift is different from other SRS cyclic shifts used for other narrowband regions;
• or
• an SRS comb index, wherein the SRS comb index is different from other SRS comb indexes used for other narrowband regions;
• decide whether or not to transmit SRS on the determined time-frequency SRS transmission resources of the first subframe;
• and
• transmit or refrain from transmitting not transmit the SRS on the determined time-frequency SRS transmission resources of the first subframe based on the decision.

An apparatus for wireless communications, comprising:

• means for determining one or more narrowband regions partitioned from wider system bandwidth for communicating with a network entity;
• means for determining time-frequency sounding reference signal (SRS) transmission resources, within the one or more narrowband regions of a first subframe, for transmitting SRSs, using at least one of:
• an SRS cyclic shift, wherein the SRS cyclic shift is different from other SRS cyclic shifts used for other narrowband regions;
• or
• an SRS comb index, wherein the SRS comb index is different from other SRS comb indexes used for other narrowband regions;
• means for deciding whether to transmit SRS on the determined time-frequency SRS transmission resources of the first subframe;
• and
• means for transmitting or refraining from transmitting the SRS on the determined time-frequency SRS transmission resources of the first subframe based on the decision.

A non-transitory computer-readable medium for wireless communications, comprising code, which when executed by at least one processor of an apparatus, causes the apparatus to:

• determine one or more narrowband regions partitioned from wider system bandwidth for communicating with a network entity;
• determine time-frequency sounding reference signal (SRS) transmission resources, within the one or more narrowband regions of a first subframe, for transmitting SRSs, using at least one of:
• an SRS cyclic shift, wherein the SRS cyclic shift is different from other SRS cyclic shifts used for other narrowband regions;
• or
• an SRS comb index, wherein the SRS comb index is different from other SRS comb indexes used for other narrowband regions;
• decide whether or not to transmit SRS on the determined time-frequency SRS transmission resources of the first subframe;
• and
• transmit or refrain from transmitting the SRS on the determined time-frequency SRS transmission resources of the first subframe based on the decision.