Transmitter and method of transmitting and receiver and method of receiving

A method of transmitting data, the method comprising

• encoding the data to form forward error correction encoded frames of encoded data cells,
• forming a service frame for transmission comprising a plurality of the forward error correction encoded frames,
• convolutionally interleaving the encoded data cells of the plurality of the forward error correction encoded frames of the service frames using a convolutional interleaver comprising a plurality of delay portions,
• mapping the interleaved and encoded data cells of the service frames onto modulation cells,
• modulating one or more carriers with the modulation cells for transmission, and
• forming signalling data to be transmitted with the service frames to a receiver to include an indication of an identified first of the encoded data cells of a first of the plurality of forward error correction encoded frames of a service frame which can be decoded from encoded data cells received from the service frame or the service frame and one or more other service frames following after the service frame.

A receiver for recovering data symbols from a received signal, the receiver comprising

• a demodulator configured to detect the received signal comprising a convolutionally interleaved symbol stream comprising a sequence of service frames, each service frame including one or more forward error correction encoded frames of encoded data cells,
• convolutional deinterleaver circuitry comprising a plurality of delay portions and configured to convolutionally deinterleave the received encoded data cells,
• a forward error correction decoder configured to decode the encoded frames of encoded data cells, and
• controller circuitry configured
• to detect a service frame,
• to detect from which of the plurality of delay portions of the convolutional deinterleaver circuitry a first encoded data cell of a service frame is read,
• to detect the number of the service frame encoded data cells of the service frame after which a first forward error correction frame is read, and
• to detect, based upon the detected service frame, the delay portion from which a first encoded data cell of the service frame is read, and the number of the service frame encoded data cells of the service frame after which a first encoded data cell of one of more of the forward error correction frames is read, whether any encoded data cells of the one or more forward error correction frames were transmitted in a previous service frame, and
• if any of the encoded data cells of the one or more of the forward error correction frames were transmitted in a previous service frame not received by the receiver, not to decode the forward error correction frame, or
• if no encoded data cells of one or more of the forward error correction frame were transmitted in the previous service frame, or if any encoded data cells of the new forward error correction frame were transmitted in a received previous service frame,
• to decode the forward error correction frames to recover the stream if data symbols.

A method for recovering data symbols from a received signal, the method comprising

• detecting the received signal, the received signal comprising an interleaved stream of encoded data cells comprising a sequence of service frames, each service frame including one or more forward error correction encoded frames of encoded data cells,
• convolutional deinterleaving the stream of encoded data cells using a plurality of delay portions,
• decoding the encoded frames of encoded data cells, wherein the decoding the encoded frames comprises
• detecting a service frame,
• detecting from which of the delay portions a first service frame data symbol of the new service frame is read for the convolutional deinterleaving,
• detecting the number of the encoded data cells of the service frame after which a first forward error correction frame is read,
• detecting, based upon the detected service frame, the delay portion from which a first encoded data cell of the service frame is read, and the number of the encoded data cells of the service frame after which a first encoded data cell of one or more of the forward error correction frames is read, whether any encoded data cells of one or more of the forward error correction frames were transmitted in a previous service frame, and
• if any of the encoded data cells of one or more of the forward error correction frames were transmitted in a previous service frame, not decoding the forward error correction frame, or
• if no encoded data cells of the one or more of the forward error correction frames were transmitted in a previous service frame, decoding the forward error correction frame to recover the stream if data symbols.

A television comprising a receiver for recovering data symbols from a received signal, the receiver comprising

• a demodulator configured to detect the received signal comprising a convolutionally interleaved symbol stream comprising a sequence of service frames, each service frame including one or more forward error correction encoded frames of encoded data cells,
• convolutional deinterleaver circuitry comprising a plurality of delay portions and configured to convolutionally deinterleave the received encoded data cells,
• a forward error correction decoder configured to decode the encoded frames of encoded data cells, and
• controller circuitry configured
• to detect a service frame,
• to detect from which of the plurality of delay portions of the convolutional deinterleaver circuitry a first encoded data cell of a service frame is read,
• to detect the number of the service frame encoded data cells of the service frame after which a first forward error correction frame is read, and
• to detect, based upon the detected service frame, the delay portion from which a first encoded data cell of the service frame is read, and the number of the service frame encoded data cells of the service frame after which a first encoded data cell of one of more of the forward error correction frames is read, whether any encoded data cells of the one or more forward error correction frames were transmitted in a previous service frame, and
• if any of the encoded data cells of the one or more of the forward error correction frames were transmitted in a previous service frame not received by the receiver, not to decode the forward error correction frame, or
• if no encoded data cells of one or more of the forward error correction frame were transmitted in the previous service frame, or if any encoded data cells of the new forward error correction frame were transmitted in a received previous service frame,
• to decode the forward error correction frames to recover the stream if data symbols.