Low complexity blind detection of code rate
Blind detection of code rates for codes with incremental shortening involves determining a decoding code rate for decoding words that are based on codewords of a code that exhibits incremental shortening over a range of code rates. Incremental shortening is a code structure or coding property according to which different numbers of bits in encoding blocks that are to be encoded are set or frozen to a fixed value, to provide the range of code rates. This property enables blind detection of a decoding code rate, without explicit signaling or prior configuration of code rates between a transmitter and a receiver.
1. A method comprising:
receiving, by a wireless receiving device, a word that is based on a codeword of a polar or Low Density Parity Check (LDPC) code, the polar or LDPC code having an incremental shortening property over a range of code rates such that an information bit frozen to a value for a code rate is also frozen to the same value for lower code rates;
performing, by the wireless receiving device, a blind detection of a code rate within the range of code rates of the polar or LDPC code; and
decoding, by the wireless receiving device, the received word using the blindly detected code rate.
2. The method of claim 1 , wherein performing a blind detection comprises:
determining a Signal to Noise Ratio (SNR) of the received word; and
determining, based on the determined SNR, the code rate to be used in decoding the received word.
3. The method of claim 2 , wherein determining the code rate comprises determining a code rate associated with a longest block of information bits that can be successfully decoded from the received word at the determined SNR.
4. The method of claim 1 , wherein performing the blind detection comprises blindly selecting a first code rate, and wherein the method further comprises:
determining whether the decoding at the first code rate was successful; and
decoding the received word using a second code rate lower than the first code rate in response to determining that the decoding at the first code rate was not successful.
5. The method of claim 1 , further comprising:
determining whether an information bit block decoded by decoding the received word using the blindly detected code rate is followed by one or more extra bits.
6. The method of claim 5 , further comprising:
discarding the one or more extra bits in response to determining that the information bit block decoded by decoding the received word using the blindly detected code rate is followed by the one or more extra bits.
7. The method of claim 5 , further comprising:
determining, based on the one or more extra bits, the code rate within the range of code rates of the polar or LDPC code in response to determining that the information bit block is followed by the one or more extra bits.
8. The method of claim 5 , wherein determining whether the information bit block is followed by the one or more extra bits comprises performing a Cyclic Redundancy Check (CRC).
9. The method of claim 1 :
wherein the receiving comprises receiving on a control channel;
wherein the performing comprises blind detection of a plurality of code rates within the range of code rates of the polar or LDPC code; and
wherein the decoding comprises decoding using each code rate of the plurality of blindly detected code rates.
10. The method of claim 9 , wherein the receiving comprises receiving in respective different communication resources.
11. The method of claim 9 , wherein the plurality of blindly detected code rates correspond to different types of messages.
12. The method of claim 9 , wherein the control channel is a Physical Downlink Control Channel (PDCCH).
13. A non-transitory processor-readable medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform a method comprising:
receiving a word that is based on a codeword of a polar or Low Density Parity Check (LDPC) code, the polar or LDPC code having an incremental shortening property over a range of code rates such that an information bit frozen to a value for a code rate is also frozen to the same value for lower code rates;
performing a blind detection of a code rate within the range of code rates of the polar or LDPC code, to be used in decoding the received word; and
decoding the received word using the blindly detected code rate.
14. An apparatus comprising:
a wireless receiver configured to receive a word that is based on a codeword of a polar or Low Density Parity Check (LDPC) code, the polar or LDPC code having an incremental shortening property over a range of code rates of the polar or LDPC code such that an information bit frozen to a value for a code rate is also frozen to the same value for lower code rates; and
a decoder, operatively coupled to the wireless receiver, configured to:
perform a blind detection of a code rate within the range of code rates of the polar or LDPC code; and
decode the received word using the blindly detected code rate.
15. The apparatus of claim 14 , wherein the decoder is configured to perform the blind detection by determining a Signal to Noise Ratio (SNR) of the received word, and determine, based on the determined SNR, the code rate to be used in decoding the received word.
16. The apparatus of claim 14 , wherein the decoder is configured to determine the code rate by determining a code rate associated with a longest block of information bits that can be successfully decoded from the received word at the determined SNR.
17. The apparatus of claim 14 , wherein the decoder is configured to:
perform the blind detection by blindly selecting a first code rate,
determine whether the decoding at the first code rate was successful; and
decode the received word using a second code rate lower than the first code rate in response to determining that the decoding at the first code rate was not successful.
18. The apparatus of any one of claim 14 , wherein the decoder is further configured to determine whether an information bit block decoded by decoding the received word using the blindly detected code rate is followed by one or more extra bits.
19. The apparatus of claim 18 , wherein the decoder is further configured to discard the one or more extra bits in response to determining that the information bit block is followed by the one or more extra bits.
20. The apparatus of claim 18 , wherein the decoder is further configured to determine, based on the one or more extra bits, the code rate within the range of code rates of the polar or LDPC code in response to determining that the information bit block is followed by the one or more extra bits.
21. The apparatus of claim 18 , wherein the decoder is configured to determine whether the information block is followed by the one or more extra bits performing a Cyclic Redundancy Check (CRC).
22. The apparatus of claim 14 :
wherein the wireless receiver is configured to receive on a control channel; and
wherein the decoder is configured to perform blind detection of a plurality of code rates within the range of code rates, and to decode using each code rate of the plurality of blindly detected code rates.
23. The apparatus of claim 22 , wherein the wireless receiver is configured to receive in respective different communication resources.
24. The apparatus of claim 22 , wherein the plurality of blindly detected code rates correspond to different types of messages.
25. The apparatus of claim 22 , wherein the control channel is a Physical Downlink Control Channel (PDCCH).
26. The apparatus of claim 14 , wherein the apparatus is a user equipment.
27. The apparatus of claim 14 , wherein the apparatus is a communication network equipment.