LPWAN communication protocol design with turbo codes
AssigneeStar Ally International Limited
InventorsWenwen Tu, Wensheng Hua
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Abstract
A method and a decoder for receiving a message encoded in Turbo Codes and modulated for transmission as an analog signal includes: (a) demodulating the analog signal to recover the Turbo Codes; and (b) decoding the Turbo Codes to recover the message using an iterative Turbo Code decoder, wherein the decoding includes performing an error detection after a predetermined number of iterations of the Turbo Code decoder to determine whether or not an error has occurred during the transmission. The predetermined number of iterations may be, for example, two. Depending on the result of the error detection, the decoding may stop, a request for retransmission of the message may be sent, or further iterations of decoding in the Turbo Code decoder may be carried out.
Claims27
A method for decoding an encoded message in an analog signal received at a receiver to obtain a decoded message, wherein the encrypted encoded message is (i) encoded according to an error detection scheme, (ii) further encoded in Turbo Codes, and (iii) modulated for transmission as a plurality of analog values in the analog signal;
- the method for decoding comprising:
- (i) based on channel condition, determining a required number of iterations necessary to achieve a predetermined bit error rate in the decoded message;
- (ii) demodulating the analog signal to recover the Turbo Codes-encoded message;
- (iii) iteratively decoding the Turbo Codes-encoded message for a predetermined number of iterations that is less than the required number of iterations to obtain a current result, wherein the iterative decoding is performed in conjunction with evaluating a probability that the current result corresponds to a correctly received message, the probability relating to the deviation of the analog values in the analog signal received from their corresponding values at transmission;
- and
- (iv) (a) applying the error detection scheme to determine from the current result whether or not the message has been successfully decoded;
- and (b) when the message is determined not to have been successfully decoded, returning to step (iii) of the method for decoding for further iterative decoding of the Turbo Codes-encoded message.
A decoder for decoding an encoded message in an analog signal received at a receiver to obtain a decoded message, wherein the message is (i) encoded according to an error detection scheme, (ii) further encoded in Turbo Codes, and (iii) modulated for transmission as a plurality of analog values in the analog signal;
- the decoder comprising:
- a demodulator that demodulates the analog signal to recover the Turbo Codes-encoded message;
- and
- an iterative Turbo Code decoder that (i) based on channel condition, determines a required number of iterations necessary to achieve a predetermined bit error rate in the decoded message;
- (ii) provides a current result after a predetermined number of iterations of decoding the encoded message that is less than the required number;
- (iii) upon application of the error detection scheme on the current result, determines whether or not the encoded message has been successfully decoded;
- and (iv) returns to further iterative decoding of the encoded message when the encoded message is determined not to have been successfully decoded, wherein the iterative Turbo Code decoder operates in conjunction with evaluating a probability that the current result corresponds to a correctly received message, the probability relating to the deviation of the analog values in the analog signal received from their corresponding values at transmission.
In a receiver, a method for iteratively decoding an encoded message in an analog signal to achieve a decoded message, wherein
- (i) the encoded message results from an encoding method that comprises:
- including in the message an error decoding code, according to an error detection scheme;
- encoding the message in Turbo Codes, and
- modulating the encoded message for transmission to the receiver as a plurality of analog values in the analog signal;
- and
- (ii) the method for iterative decoding comprises:
- (a) based on channel condition, determining a required number of iterations necessary to achieve a predetermined bit error rate in the decoded message;
- (b) after completing a predetermined number of iterations of the iterative decoding that is less than the required number of iterations, examining the error detection code to determine whether the error detection code indicates that no error has occurred during transmission;
- and
- (c) when it is determined in the iteration that no error has occurred during the transmission, terminating the iterative decoding process.
Dependencies are inferred from the claim text.