Successive interference cancellation (SIC) ordering algorithms for improved multiple-input multiple-output (MIMO) performance
Certain aspects of the present disclosure provide ordering techniques for a Successive Interference Cancellation (SIC) receiver which may be used to robustly choose a correct stream for first decode under varying data rates, SNR and mobile propagation conditions in Multiple Input Multiple Output (MIMO) systems. The SIC ordering techniques discussed in the disclosure include SNR and/or Rate based information theoretic approach. For example, the SIC receiver may evaluate an SNR based or RATE-based information theoretic metric for the MIMO streams and choose one stream with a higher value of the metric for decoding first. A speculative single code block based approach is may also be used for selecting a stream for first decode, by leveraging the presence of per code block Cyclic Redundancy Check (CRC) and the lack of time diversity in LTE systems.
1. A method for wireless communication by a receiver, comprising:
receiving at least two streams of data;
selecting at least one of the received streams to decode first, from a comparison of a metric corresponding to at least two of the streams, the metric based on a gap between a measured value of a parameter and an allocated value of the parameter, wherein the parameter comprises a data rate; and
performing interference cancelation using results of decoding the selected at least one stream to decode at least one non-selected stream.
2. The method of claim 1 , further comprising:
determining the metric for a stream of data using a measured value of the parameter and an allocated value of the parameter for the stream.
3. The method of claim 2 , wherein the metric is averaged over multiple transmissions for the stream.
4. The method of claim 1 , wherein selecting one of the received streams to decode first comprises:
selecting a stream corresponding to the largest metric value.
5. The method of claim 1 , wherein the allocated value of the parameter for a stream is determined using a number of symbols used for each transmission of the stream and a transport block size.
6. An apparatus for wireless communication, comprising:
means for receiving at least two streams of data;
means for selecting at least one of the received streams to decode first, from a comparison of a metric corresponding to at least two of the streams, the metric based on a gap between a measured value of a parameter and an allocated value of the parameter, wherein the parameter comprises a data rate; and
means for performing interference cancelation using results of decoding the selected at least one stream to decode at least one non-selected stream.
7. The apparatus of claim 6 , further comprising:
means for determining the metric for a stream of data using a measured value of the parameter and an allocated value of the parameter for the stream.
8. The apparatus of claim 7 , wherein the metric is averaged over multiple transmissions for the stream.
9. The apparatus of claim 6 , wherein the means for selecting at least one of the received streams to decode first is configured to:
select a stream corresponding to the largest metric value.
10. The apparatus of claim 6 , wherein the allocated value of the parameter for a stream is determined using a number of symbols used for each transmission of the stream and a transport block size.
11. An apparatus for wireless communication, comprising:
at least one processor configured to:
receive at least two streams of data;
select at least one of the received streams to decode first, from a comparison of a metric corresponding to at least two of the streams, the metric based on a gap between a measured value of a parameter and an allocated value of the parameter, wherein the parameter comprises a data rate; and
perform interference cancelation using results of decoding the selected at least one stream to decode at least one non-selected stream; and
a memory coupled to the at least one processor.
12. A computer program product for wireless communication, comprising:
A non-transitory computer readable medium having instructions stored thereon executed by a processor to perform a method comprising:
receiving at least two streams of data;
selecting at least one of the received streams to decode first, from a comparison of a metric corresponding to at least two of the streams, the metric based on a gap between a measured value of a parameter and an allocated value of the parameter, wherein the parameter comprises a data rate; and
performing interference cancelation using results of decoding the selected at least one stream to decode at least one non-selected stream.