Scrambling sequence design for embedding UE ID into frozen bits for DCI blind detection
Methods and devices are described for encoding and decoding control information that has been modulated based on one or more identifiers of the transmitter and/or receiver. Some embodiments describe scrambling sequence design for multi-mode block discrimination on downlink control information (DCI) blind detection. Separate scrambling masks may be applied to disparate bit fields within a coded DCI message, wherein each of the scrambling masks is derived from a unique identifier associated with either the transmitter or the intended receiver. The scrambling masks may be used by the receiver to perform early termination of the decoding process, to mitigate intercell interference, and to verify that the receiver is the intended receiver.
1. A base station comprising:
a radio; and
a processing element coupled to the radio;
wherein the radio and the processing element are configured to:
represent user equipment (UE)-specific control information as a plurality of frozen bits and a plurality of information bits of a polar code;
modulate at least a subset of the plurality of frozen bits based on a UE-specific identifier to produce modulated control information, wherein at least the subset of the plurality of frozen bits are selected for modulation whereby at least the subset of the plurality of frozen bits occur within the control information after an information bit with a predetermined threshold level of reliability, wherein the plurality of information bits of the control information is not modulated based on the UE-specific identifier;
encode the modulated control information using the polar code to obtain encoded modulated control information; and
wirelessly transmit the encoded modulated control information.
2. The base station of claim 1 ,
wherein the radio and the processing element are further configured to:
generate a pseudorandom sequence of bits based on the UE-specific identifier, wherein the pseudorandom sequence of bits is the same length as the plurality of frozen bits,
wherein modulating at least a subset of the plurality of frozen bits based on the UE-specific identifier comprises modulating the plurality of frozen bits with the pseudorandom sequence of bits.
3. The base station of claim 1 ,
wherein the at least a subset of the plurality of frozen bits are selected to balance a reliability and a latency associated with decoding of the encoded modulated control information by a UE.
4. The base station of claim 1 ,
wherein the encoded modulated control information is transmitted to one or more UEs for performing downlink control information (DCI) blind detection.
5. A user equipment device (UE), comprising:
a radio; and
a processor coupled to the radio;
wherein the UE is configured to:
receive a first polar coded message in a wireless manner from a base station, the first polar coded message comprising an encoding of a plurality of frozen bits and a plurality of information bits;
implement a decoding procedure on the first polar coded message, wherein, in implementing the decoding procedure, the UE is configured to:
begin a decode of the first polar coded message to produce a subset of the frozen bits;
perform a cross-correlation calculation based on the subset of the frozen bits and a corresponding subset of reference bits, wherein the reference bits are based on an identifier of the UE;
abort the decoding procedure based on a determination that the result of the cross-correlation calculation is below a cross-correlation threshold.
6. The UE of claim 5 ,
wherein the reference bits are a pseudorandom sequence of bits generated from the identifier of the UE, wherein the pseudorandom sequence of bits is the same length as the plurality of frozen bits.
7. The UE of claim 5 ,
wherein the subset of the plurality of frozen bits is selected to balance a reliability and a latency associated with the decoding procedure.
8. The UE of claim 5 ,
wherein the first polar coded message is received and the decoding procedure is initiated as part of a downlink control information (DCI) blind detection procedure.
9. The UE of claim 5 ,
wherein the processor and the radio are further configured to:
receive a second polar coded message in a wireless manner from the base station; and
subsequent to aborting the decoding procedure on the first polar coded message, implement the decoding procedure on the second polar coded message.
10. The UE of claim 5 ,
wherein the processor comprises a plurality of parallelized processing elements;
wherein the radio and the processor are further configured to:
receive one or more additional polar coded messages in a wireless manner from the base station; and
implement, by separate ones of the parallelized processing elements; the decoding procedure on each of the received one or more additional polar coded messages.
11. The UE of claim 5 ,
wherein the processor comprises a plurality of parallelized processing elements;
wherein said decoding procedure is a successive cancellation list (SCL) decoding procedure; and
wherein separate ones of the plurality of parallelized processors are configured to perform decoding procedures on separate respective bit paths of the SCL decoding procedure.
12. The UE of claim 5 ,
wherein, in implementing the decoding procedure on the first polar coded message, the UE is further configured to:
continue the decode of the first polar coded message to produce the plurality of information bits based on a determination that the result of the cross-correlation calculation is above the cross-correlation threshold.
13. A method for decoding control information, comprising:
by a user equipment device (UE):
receiving a first polar coded message in a wireless manner from a base station, the first polar coded message comprising an encoding of a plurality of frozen bits and a plurality of information bits;
implementing a decoding procedure on the first polar coded message by:
beginning decoding the first polar coded message to produce a subset of the frozen bits;
performing a cross-correlation calculation based on the subset of the frozen bits and a corresponding subset of reference bits, wherein the reference bits are based on an identifier of the UE;
aborting the decoding procedure based on a determination that the result of the cross-correlation calculation is below a cross-correlation threshold.
14. The method of claim 13 ,
wherein the reference bits are a pseudorandom sequence of bits generated from the identifier of the UE, wherein the pseudorandom sequence of bits is the same length as the plurality of frozen bits.
15. The method of claim 13 ,
wherein the first polar coded message is received and the decoding procedure is initiated as part of a downlink control information (DCI) blind detection procedure.
16. The method of claim 13 , the method further comprising:
receiving a second polar coded message in a wireless manner from the base station; and
subsequent to aborting the decoding procedure on the first polar coded message, implementing the decoding procedure on the second polar coded message.
17. The method of claim 13 ,
wherein the UE comprises a plurality of parallelized processing elements;
wherein the method further comprises:
receiving one or more additional polar coded messages in a wireless manner from the base station; and
implementing, by separate ones of the parallelized processing elements; the decoding procedure on each of the received one or more additional polar coded messages.
18. The method of claim 13 ,
wherein the decoding procedure is a successive cancellation list decoding procedure; and
wherein said cross-correlation calculation comprises calculating a divergence of path metrics associated with the subset of decoded frozen bits and the corresponding subset of reference bits.
19. The method of claim 13 , wherein implementing the decoding procedure further comprises:
continuing decoding the first polar coded message to produce the plurality of information bits based on a determination that the result of the cross-correlation calculation is above the cross-correlation threshold.