Transmitter and method of transmitting and receiver and method of receiving

Patent metadata

Field	Value
Publication number	US-2016173233-A1
Application number	US-201514969418-A
Country	US
Kind code	A1
Filing date	Dec 15, 2015
Priority date	Dec 15, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

A transmitter transmits data using Orthogonal Frequency Division, OFDM, symbols. The transmitter comprising a forward error correction encoder configured to encode the data to form forward error correction encoded frames of encoded data cells, a service frame builder configured to form a service frame for transmission comprising a plurality of forward error correction encoded frames, a convolutional interleaver comprising a plurality of delay portions and configured to convolutionally interleave the data cells of the service frames, a modulation symbol mapper configured to map the interleaved and encoded data cells of the service frames onto modulation cells, and a modulator configured to modulate the sub-carriers of one or more OFDM symbols with the modulation cells. A controller is configured to form signalling data to be transmitted to include an indication of an identified first cell of a first of the forward error correction frame of a new service frame which can be decoded from cells received from the new service frame or the new service frame and one or more service frames following after the new service frame. By detecting the first cell of a first of the error correction encoded frames of a new service frame which does not have any data cells in one or more previous service frames as a result of the convolutional interleaving then a receiver, which has acquired the new service frame but none of the one or more previous service frames can decode this first forward error correction encoded frame of the new service frame and ignore the other forward error correction encoded frames earlier in the service frame. Therefore for example a receiver may power on or channels during a previous service frame and be directed to only decode a forward error correction encoded frame that it can decode.

First claim

1 . A transmitter for transmitting data, the transmitter comprising
a forward error correction encoder configured to encode the data to form forward error correction encoded frames of encoded data cells, a service frame builder configured to form a service frame for transmission comprising a plurality of the forward error correction encoded frames, a convolutional interleaver comprising a plurality of delay portions and configured to convolutionally interleave the encoded data cells of the plurality of the forward error correction encoded frames of the service frames, a modulation symbol mapper configured to map the interleaved and encoded data cells of the service frames onto modulation cells, and a modulator configured to modulate one or more carriers with the modulation cells for transmission, and a controller configured to form signalling data to be transmitted with the service frames 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.

2 . The transmitter as claimed in claim 1 , wherein the controller is configured
to calculate a displacement value (A) representing a minimum displacement from the first of the encoded data cells of the service frame to a first encoded data cell of a first of the forward error correction frames, for which none of the encoded data cells of the forward error correction frame will be transmitted in one or more previous service frames, and to form the indication of the identified first encoded data cell from the first cell of the service frame providing a first of the forward error correction encoded frames in the service frame which has a encoded data cell index equal to or after the calculated displacement value.

3 . The transmitter as claimed in claim 2 , wherein the controller is configured
to detect the service frame, to detect from which of the plurality of delay portions of the convolutional interleaver circuitry a first encoded data cell of the service frame is read, to calculate the displacement value (A) based upon the detected service frame and the delay portion from which the first encoded data cell of the service frame is read, to identify the first encoded data cell of a first of the forward error correction frames, after the encoded data cell index of the first encoded data cell of the service frame, which is more than the displacement value (A) from the first encoded data cell of the service frame; and to form the signalling data with the indication of the first encoded data cell of the first of the forward error correction encoded frames of the service frame which can be decoded from encoded data cells received from the service frame.

4 . The transmitter as claimed in claim 2 , wherein each of the plurality of delay portions of the convolutional interleaver is arranged to delay the encoded data cells from an input to an output by a different amount, the delay portions being arranged in a sequence, the convolutional interleaver comprising
an input commutator configured to input the encoded data cells to the delay portions so that successive data cells are input in accordance with the sequence of the delay portions, and an output commutator configured to read the encoded data cells from the delay portions by successively selecting the data cells from the outputs of the delay portions in accordance with the sequence of the delay portions to form the interleaved and forward error correction encoded data cells.

5 . The transmitter as claimed in claim 4 , wherein the displacement value A is based on a multiplication of a factor R s by a number of delay portions N r , where
R s =(PLP_TI_FECFRAME_START+PLP_TI_START_ROW) (mod N r ) and where PLP_TI_FECFRAME_START is the number of service frame data cells of the new service frame after which the first data symbol of the first forward error correction frame is read and PLP_TI_START_ROW is the delay portion from which the first service frame data symbol of the new service frame is read.

6 . The transmitter as claimed in claim 5 , wherein a first of the plurality of delay portions of the sequence of the convolutional interleaver is arranged to delay the encoded data cells from the input to the output by the greatest amount compared to the other delay portions in the sequence, and a last of the delay portions in the sequence is arranged to delay the encoded data cells by the least amount, and the displacement value A is calculated in accordance with A=((N r −1)−R s )*(N r −1).

7 . The transmitter as claimed in claim 5 , wherein a first of the plurality of delay portions of the sequence of the convolutional interleaver is arranged to delay the encoded data cells from the input to the output by the least amount compared to the other delay portions in the sequence, and a last of the delay portions in the sequence is arranged to delay the encoded data cells by the greatest amount, and the displacement value A is calculated in accordance with A=R s *(N r +1).

8 . The transmitter as claimed in claim 5 , wherein controller is configured to form the layer 1 signalling data to include PLP_TI_FECFRAME_START and PLP_TI_START_ROW.

9 . The transmitter as claimed in claim 1 , wherein each of the delay portions includes one or more memory elements and the controller is configured to set the initial content of the memory elements of the interleaver before inputting the encoded data cells with predetermined values.

10 . The transmitter as claimed in claim 9 , wherein the predetermined values include symbols derived from a constant amplitude zero auto-correlation, CAZAC, sequence.

11 . The transmitter as claimed in claim 1 , wherein the number of memory elements is N r ·(N r −1)/2, where N r is the number of rows of the convolutional interleaver.

12 . 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.

13 . 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, a

Assignees

• Sony Corp

Inventors

• Loghin Nabil Sven
• Ikegaya Ryoji

Classifications

• H04L1/0045

  Arrangements at the receiver end · CPC title

• H04L27/14

  Demodulator circuits; Receiver circuits · CPC title

• H04L1/0041

  Arrangements at the transmitter end · CPC title

• H04L1/0059

  Convolutional codes · CPC title

• H04L5/0007

  the frequencies being orthogonal, e.g. OFDM(A) or DMT · CPC title