Restrict the positioning reference signal bandwidth in NB-IoT to save power
Aspects of the disclosure are related to a method, apparatus and system for adjusting a processing bandwidth or frequency domain buffer decimation associated with reference signals, for example, positioning reference signals (PRS). By reducing the number of, for example, resource blocks and/or resource elements to be processed, the power involved in processing the reference signal can be reduced. Hence, in some implementations, aspects of the disclosure can enable low-power low-bandwidth devices, such as NarrowBand Internet of Things (IoT) (NBIoT), to decode reference signals such as PRS.
1. A method implemented at a user equipment (UE) for adjusting a frequency domain (FD) buffer decimation of a reference signal, the method comprising:
determining a present Carrier-to-Interference-and-Noise Ratio (CINR) associated with the reference signal;
determining whether the present CINR associated with the reference signal is greater than an upper reference signal CINR threshold; and
increasing the FD buffer decimation of the reference signal, in response to determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
2. The method of claim 1 , further comprising reducing a processing bandwidth associated with the reference signal from a full bandwidth in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
3. The method of claim 1 , further comprising reducing a processing bandwidth associated with the reference signal in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold, wherein the reducing the processing bandwidth comprises decoding a central bandwidth portion of the reference signal.
4. The method of claim 1 , wherein the reference signal is a positioning reference signal (PRS) and further comprising:
determining the upper reference signal CINR threshold based on one or both of: a present processing bandwidth associated with the PRS, or an NPRS parameter indicative of a number of consecutive PRS subframes in each PRS positioning occasion.
5. The method of claim 1 , wherein the FD buffer decimation of the reference signal is a decimation of sub-carriers of an Orthogonal Frequency Division Multiplexing (OFDM) signal by an integer factor.
6. The method of claim 1 , further comprising:
processing the reference signal at the FD buffer decimation to obtain reference signal time difference (RSTD) measurements; and
determining a location of the UE with Observed Time Difference of Arrival (OTDOA) positioning based on the RSTD measurements.
7. The method of claim 1 , wherein a processing bandwidth associated with the reference signal is reduced at least once and the FD buffer decimation of the reference signal is increased at least once.
8. The method of claim 1 , wherein the UE is in communication with a Long-Term Evolution (LTE) network.
9. An apparatus configured to adjust a frequency domain (FD) buffer decimation of a reference signal, the apparatus comprising:
a memory; and
a processor coupled to the memory, the processor configured to:
determine a present Carrier-to-Interference-and-Noise Ratio (CINR) associated with the reference signal;
determine whether the present CINR associated with the reference signal is greater than an upper reference signal CINR threshold; and
increase the FD buffer decimation of the reference signal, in response to determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
10. The apparatus of claim 9 , wherein the processor is further configured to reduce a processing bandwidth associated with the reference signal from a full bandwidth in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
11. The apparatus of claim 9 , wherein the processor is further configured to reduce a processing bandwidth associated with the reference signal bandwidth in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold, wherein reducing the processing bandwidth associated with the reference signal comprises the processor configured to decode a central bandwidth portion of the reference signal.
12. The apparatus of claim 9 , wherein the reference signal is a positioning reference signal (PRS), and wherein the processor is further configured to determine the upper reference signal CINR threshold based on one or both of: a present processing bandwidth associated with the PRS, or an NPRS parameter indicative of a number of consecutive PRS subframes in each PRS positioning occasion.
13. The apparatus of claim 9 , wherein the FD buffer decimation is a decimation of sub-carriers of an Orthogonal Frequency Division Multiplexing (OFDM) signal by an integer factor.
14. The apparatus of claim 9 , wherein the reference signal is a positioning reference signal (PRS), and wherein the processor is further configured to:
process the PRS at the FD buffer decimation to obtain reference signal time difference (RSTD) measurements; and
determine a location of the apparatus with Observed Time Difference of Arrival (OTDOA) positioning based on the RSTD measurements.
15. The apparatus of claim 9 , wherein the processor is further configured to reduce a processing bandwidth associated with the reference signal at least once and increase the FD buffer decimation of the reference signal at least once.
16. The apparatus of claim 9 , wherein the apparatus is in communication with a Long-Term Evolution (LTE) network.
17. An apparatus for adjusting a frequency domain (FD) buffer decimation of a reference signal, the apparatus comprising:
means for determining a present Carrier-to-Interference-and-Noise Ratio (CINR) associated with the reference signal;
means for determining whether the present CINR associated with the reference signal is greater than an upper reference signal CINR threshold; and
means for increasing the FD buffer decimation of the reference signal, in response to determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
18. The apparatus of claim 17 , further comprising means for reducing a processing bandwidth associated with the reference signal from a full bandwidth in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
19. The apparatus of claim 17 , further comprising means for reducing a processing bandwidth associated with the reference signal in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold, wherein the means for reducing the processing bandwidth associated with the reference signal comprises means for decoding a central bandwidth portion of the reference signal.
20. The apparatus of claim 17 , wherein the reference signal is a positioning reference signal (PRS) and further comprising:
means for determining the upper reference signal CINR threshold based on one or both of: a present processing bandwidth associated with the PRS, or an NPRS parameter indicative of a number of consecutive PRS subframes in each PRS positioning occasion.
21. The apparatus of claim 17 , wherein the FD buffer decimation is a decimation of sub-carriers of an Orthogonal Frequency Division Multiplexing (OFDM) signal by an integer factor.
22. The apparatus of claim 17 , further comprising:
means for processing the reference signal at the FD buffer decimation to obtain reference signal time difference (RSTD) measurements; and
means for determining a location of the apparatus with Observed Time Difference of Arrival (OTDOA) positioning based on the RSTD measurements.
23. The apparatus of claim 17 , wherein a processing bandwidth associated with the reference signal is reduced at least once and the FD buffer decimation of the reference signal is increased at least once.
24. A non-transitory computer-readable medium comprising code which, when executed by a processor, instructs the processor to perform a procedure implemented at a User Equipment (UE) for adjusting a frequency domain (FD) buffer decimation of a reference signal, the procedure comprising:
determining a present Carrier-to-Interference-and-Noise Ratio (CINR) associated with the reference signal;
determining whether the present CINR associated with the reference signal is greater than an upper reference signal CINR threshold; and
increasing the FD buffer decimation of the reference signal, in response to determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
25. The non-transitory computer-readable medium of claim 24 , wherein the procedure further comprises reducing a processing bandwidth associated with the reference signal from a full bandwidth in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold.
26. The non-transitory computer-readable medium of claim 24 , wherein the procedure further comprises reducing a processing bandwidth associated with the reference signal in response to the determining that the present CINR associated with the reference signal is greater than the upper reference signal CINR threshold, and wherein the procedure comprising reducing the processing bandwidth comprises a procedure comprising decoding a central bandwidth portion of the reference signal.
27. The non-transitory computer-readable medium of claim 24 , wherein the reference signal is a positioning reference signal (PRS) and wherein the procedure further comprises determining the reference signal CINR threshold based on one or both of: a present processing bandwidth associated with the PRS, or an NPRS parameter indicative of a number of consecutive PRS subframes in each PRS positioning occasion.
28. The non-transitory computer-readable medium of claim 24 , wherein the procedure further comprises:
processing the reference signal at the FD buffer decimation to obtain reference signal time difference (RSTD) measurements; and
determining a location of the UE with Observed Time Difference of Arrival (OTDOA) positioning based on the RSTD measurements.
29. The non-transitory computer-readable medium of claim 24 , wherein the FD buffer decimation is a decimation of sub-carriers of an Orthogonal Frequency Division Multiplexing (OFDM) signal by an integer factor.