Symbol interleaving for parameter estimation

A method for a receiver apparatus configured to receive a packet having second type symbols interleaved amongst first type symbols, the method comprising:

• demodulating the first and second type symbols, in the received packet, to acquire symbol decisions for the second type symbols and soft symbol values for the first type symbols, wherein:
• the first type symbols carry a first part of data that is encoded by a first error-correcting code and the first type symbols are demodulated using a first modulation alphabet,
• the second type symbols carry a second part of the data that is encoded by the first error-correcting code and the second type symbols are demodulated using a second modulation alphabet that is smaller than the first modulation alphabet,
• the second type symbols are for communication parameter estimation,
• one or more of the following associated with the second type symbols are based one or more conditions associated with the packet:
• an interleaving density of the second type symbols amongst the first type symbols, a type of the second modulation alphabet, and a size of the second modulation alphabet, and
• the one or more conditions associated with the packet include one or more of the following:
• a worst case phase drift for the packet, a worst case amplitude variation for the packet, and a required signal quality for the first type symbols to meet a performance target for the packet;
• and
• decoding data in the received packet based on the acquired soft symbol values for the first type symbols and based on soft symbol values for the second type symbols corresponding to the acquired symbol decisions being correct.

A communication apparatus configured to control interleaving, within a packet for transmission, of second type symbols amongst first type symbols, the communication apparatus comprising controller circuitry configured to:

• determine one or more of the following parameters:
• an interleaving density of the second type symbols amongst the first type symbols,
• a type of a second modulation alphabet to be used for modulating the second type symbols, and
• a size of the second modulation alphabet, wherein:
• the first type symbols carry a first part of data that is encoded by a first error-correcting code,
• the second type symbols carry a second part of the data that is encoded by the first error-correcting code,
• the second type symbols are for communication parameter estimation, and
• the determination is based on one or more of the following:
• a worst case phase drift for the packet, a worst case amplitude variation for the packet, and a required signal quality for the first type symbols to meet a performance target for the packet,
• modulate the second part of the encoded data using the second modulation alphabet to obtain the second type symbols for interleaving within the packet;
• and
• modulate the first part of the encoded data using a first modulation alphabet that is larger than the second modulation alphabet, to obtain the first type symbols for interleaving within the packet.