Method and apparatus for quantizing soft information using linear quantization
View Patent ↗A process capable of employing compression and decompression mechanism to receive and decode soft information is disclosed. The process, in one aspect, is able to receive a data stream formatted with soft information from a communication network such as a wireless network. After identifying a set of bits representing a first logic value from a portion of the data stream in accordance with a predefined soft encoding scheme, the set of bits is compressed into a compressed set of bits. The compressed set of bits which represents the first logic value is subsequently stored in a local memory.
1. A method for processing data from a network, comprising:
receiving a first set of signals representing a first logic value from a transmitter via a communication channel;
demodulating the first set of signals in accordance with a soft decoding scheme and generating a Log Likelihood Ratio (“LLR”) value representing the first logic value;
generating a quantized LLR value via a linear quantizer in response to the LLR value;
storing the quantized LLR value representing compressed first logic value in a local storage to prevent the LLR value reaching a decoder;
extracting a sign bit from content bits of the LLR value to produce an unsigned LLR value; and
generating an unrounded result by dividing the unsigned LLR value with a predefined scale, wherein generating a quantized LLR value includes calculating an unsigned result via rounding the unrounded result to a predefined number of bits.
2. The method of claim 1 , wherein generating a quantized LLR value via the linear quantizer includes producing the quantized LLR by concatenating the unsigned result with the sign bit.
3. The method of claim 1 , wherein generating an unrounded result by dividing a predefined scale includes selecting the predefined scale from a plurality of fixed values in response to number of bits utilized in the soft decoding scheme.
4. The method of claim 1 , comprising retrieving the quantized LLR value representing the first logic value from the local storage.
5. The method of claim 4 , comprising forwarding the quantized LLR value to a soft decoder.
6. The method of claim 4 , further comprising,
extracting the sign bit from the quantized LLR value to generate an unsigned quantized LLR value; and
generating an unsigned LLR value by multiplying the unsigned quantized LLR value with the predefined scale.
7. The method of claim 6 , further comprising includes concatenating the unsigned LLR value with the sign bit to produce a decompressed LLR value.
8. The method of claim 1 , further comprising receiving a second set of signals representing a second logic value from the transmitter via the communication channel.
9. The method of claim 1 , wherein receiving the first set of signals representing the first logic value includes receiving soft information representing a logic value from the transmitter via a wireless communication channel.
10. A method for processing information transmitted across a network, comprising:
receiving a first set of signals representing a first logic value from a transmitter via a wireless communication channel;
demodulating the first set of signals in accordance with a soft decoding scheme and generating soft decoding metrics (“SDM”) coded in a Log Likelihood Ratio (“LLR”) representing the first logic value;
generating a partially quantized LLR via a linear LLR partial quantizer based on the LLR;
storing the partially quantized LLR representing compressed first logic value in a local storage to prevent the LLR reaching a decoder;
extracting a portion of least significant bits (“LSB”) from the LLR; and
generating an LSB quantized LLR by dividing the portion of LSBs with a predefined scale value and rounding quotient to a predefined number of bits, wherein generating the partially quantized LLR further includes concatenating the LSB quantized LLR with a portion of most significant bits (“MSB”) from the LLR including the sign bit to form the partially quantized LLR.
11. The method of claim 10 , further comprising:
retrieving the partially quantized LLR representing the first logic value from the local storage; and
forwarding the partially quantized LLR to a soft decoder.
12. The method of claim 10 , further comprising,
extracting the portion of quantized LSB from the partially quantized LLR;
converting the quantized LSB to LSB by multiplying the quantized LSB by the scale value; and
concatenating the LSB with a portion of most significant bits (“MSB”) from the LLR including the sign bit to produce a decompressed LLR representing the first logic value.
13. A network system, comprising:
a receiver configured to receive signals from a transmitter via a wireless communication network;
a demodulator coupled to the receiver and configured to obtain soft decoding metrics (“SDM”) in accordance with log likelihood ratio (“LLR”) calculation;
a linear compressor coupled to the demodulator and able to perform a linear LLR quantization according to a predefined fixed value to generate compressed SDM;
a storage couple to the linear compressor and able to store the compressed SDM to prevent the SDM reaching a decoder;
a decompressor coupled to the storage and configured to retrieve one of plurality of linear quantized LLR values and restoring the linear quantized LLR value to a decompressed LLR value,
wherein the linear compressor is configured to concatenate sign bit of SDM with a result of dividing the SDM by the predefined fixed value to generate a linear quantized LLR value.
14. The method of claim 13 , wherein restoring the linear quantized LLR value includes multiplying the linear quantized LLR value with the predefined fixed value.