Apparatus and method for transmitting a bit in addition to a plurality of payload data symbols of a communication protocol, and apparatus and method for decoding a data signal

An apparatus for decoding a data signal comprising a plurality of pulses of variable pulse length at predetermined positions, the apparatus comprising:

• an input interface configured to receive the data signal;
• and
• a demodulation circuit configured to:
• if a respective pulse length of each of the plurality of pulses at the predetermined positions are not longer than a maximum payload data symbol pulse length defined in a communication protocol, determine that a bit value of a bit is a first value;
• and
• if the respective pulse length of one of the plurality of pulses at the predetermined positions is longer than a maximum payload data symbol pulse length defined in the communication protocol,
• determine that the bit value of the bit is a second value;
• determine a position m of the pulse with the pulse length being longer than the maximum payload data symbol pulse length defined in the communication protocol among the plurality of pulses;
• and
• determine that a symbol value of an i-th payload data symbol of a plurality of payload data symbols is ([m−i] mod z), wherein z is the number of possible symbol values of the payload data symbols defined in the communication protocol, and wherein 1≤i≤z.

A method for transmitting a bit in addition to a plurality of payload data symbols of a communication protocol, the method comprising:

• receiving information about a bit value of the bit;
• if the bit value is a first value, transmitting the plurality of payload data symbols at predetermined positions in a data signal as pulses of variable pulse length, wherein a respective pulse length of each of the pulses of variable pulse length is selected based on the symbol value of the payload data symbol represented by each pulse of variable pulse length;
• and
• if the bit value is a second value, transmitting a pulse exhibiting an extended pulse length being longer than a maximum payload data symbol pulse length defined in the communication protocol at the predetermined position of the pulse for a d-th payload data symbol of the plurality of payload data symbols, wherein d=k+i if k+i≤z, wherein d=([k+i] mod z) if k+i>z, wherein k is the symbol value of a i-th payload data symbol of the plurality of payload data symbols, wherein z is the number of possible symbol values of the payload data symbols defined in the communication protocol, and wherein 1≤i≤z.

A method for decoding a data signal comprising a plurality of pulses of a variable pulse length at predetermined positions, the method comprising:

• receiving the data signal;
• if a respective pulse length of each of the plurality of pulses at the predetermined positions are not longer than a maximum payload data symbol pulse length defined in a communication protocol, determining that a bit value of a bit is a first value;
• and
• if the respective pulse length of one of the plurality of pulses at the predetermined positions is longer than a maximum payload data symbol pulse length defined in the communication protocol,
• determining that the bit value of the bit is a second value;
• determining a position m of the pulse with the pulse length being longer than the maximum payload data symbol pulse length defined in the communication protocol among the plurality of pulses;
• and
• determining that a symbol value of an i-th payload data symbol of a plurality of payload data symbols is ([m−i] mod z), wherein z is the number of possible symbol values of the payload data symbols defined in the communication protocol, and wherein 1≤i≤z.