US 12,235,366 B2Granted

Decoder for a receiver

AssigneeQinetiq Limited

InventorMalcolm David Macleod

Life of this patent

Estimating the term…

Loading patent…

Abstract

A non-systematic convolutional decoder of a convolutionally encoded multi-level data stream includes a shift register and two or more paths of exclusive-OR (XOR) gates, arranged to reconstruct an original input information stream, each path having a quantiser arranged to quantise the signal to two levels, and a set of XOR gates arranged to match an encoding path in an associated convolutional encoder, and a selector arranged to feed an output from each path to a single input of the shift register. If the paths have differing values at their output, the selector may choose the value from the path based upon a function of the multi-level signals associated with each path, such as the path with the largest absolute signal level. The decoder provides a simple means for decoding signals while allowing the signal to also or instead be decoded using e.g. a Viterbi decoder if higher performance is required.

Claims11

Dependent claims

A decoder for decoding a convolutionally coded signal received by a receiver, the signal being represented as a multilevel signal where the number of levels is greater than two, the decoder comprising:

a) a shift register having an input;
b) a first one-bit quantizer, arranged to receive a first polynomial-derived multilevel signal that is a part of the multilevel signal as derived from a signal produced by a first polynomial during generation of the coded signal in a transmitter, and to produce a first quantized binary bit stream therefrom;
c) a first set of at least one exclusive OR (XOR) gate(s) arranged to receive as input the first quantized binary bit stream, and to receive as further input(s) from bins from the shift register as determined by the first polynomial, the first set of XOR gates producing a first set output bit;
d) a second one-bit quantizer, arranged to receive a second polynomial-derived multilevel signal that is a part of the multilevel signal as derived from a signal produced by a second polynomial during a coding stage in a transmitter, and to produce a second quantized binary bit stream therefrom;
e) a second set of at least one XOR gate(s) arranged to receive as input the second quantized binary bit stream, and to receive as further inputs bins from the shift register as determined by the second polynomial, the second set of XOR gates producing a second set output bit;
f) a selector, having as inputs the first and second polynomial-derived multilevel signals and the first and second set output bits, and being arranged to provide, as output to the shift register, either:
i) if the value of the first and second set output bits are the same, then that value of the first and second set output bits, or
ii) if the value of the first and second set output bits are different, then either the value of the first or second set output bit dependent upon a function of the first and second polynomial derived multi-level signals;
wherein the decoder is further arranged to provide, as an output, a bit value provided to the input of the shift register.

6 more elements

A method for decoding a signal that has been convolutionally coded by a transmitter and received by a receiver, the signal being represented as a multilevel signal where the number of levels is greater than two, the method comprising the steps of,

a) quantizing, in a first one-bit quantizer, a first polynomial-derived multilevel signal that is a part of the multilevel signal as derived from a signal produced by a first polynomial during generation of the coded signal in a transmitter, producing a first quantized binary bit stream therefrom;
b) feeding the bit stream from (a) into a first set of at least one exclusive OR (XOR) gate(s), the set receiving further input(s) from bins of a shift register as determined by the first polynomial, the first set of XOR gates producing a first set output bit;
c) quantizing, in a second one-bit quantizer, a second polynomial-derived multilevel signal that is a part of the multilevel signal as derived from a signal produced by a second polynomial during a coding stage in a transmitter, and producing a second quantized binary bit stream therefrom;
d) feeding the bit stream from (c) into a second set of at least one XOR gate(s), the set receiving as further inputs bins from the shift register as determined by the second polynomial, the second set of XOR gates producing a second set output bit;
e) selecting using a selector, having as inputs the first and second polynomial multilevel signals and the first and second set output bits, the first set output bit if the absolute value of the first polynomial multilevel signal exceeds the absolute value of the second polynomial-derived multilevel signal, or otherwise the second set output bit, and providing the selected bit as an input to the shift register;
f) providing as a decoded output the bit output by a selected stage of the shift register.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/921,054Filed 7 May 2021
Priority: GB 20067487 May 2020
Published: US 2023/0176232 A18 Jun 2023
Granted: 25 Feb 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

G01S 19/243
Acquisition or tracking or demodulation of signals transmitted by the system: demodulation of navigation message
H04L 1/0054
Arrangements at the receiver end: maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
G01S 19/30
Acquisition or tracking or demodulation of signals transmitted by the system: code related
G01S 19/37
Constructional details or hardware or software details of the signal processing chain: hardware or software details of the signal processing chain