OFDM signal transmission method, transmission apparatus, and reception apparatus

A transmission method of an OFDM signal with a frame structure in which a frame contains an integer number of transport stream packets and each frame contains a specific number of symbols, the transmission method comprising:ndividing, in time base, a frame into slots, each slot including a specific number of symbols;transmitting a specific service using at least one of the slots;applying transmission channel coding to each specific service to transmit null packets or Packet Identifier (PID) packets before and after a boundary between slots transmitting different services, each PID packet not being related to the different services;inputting a frame synchronization signal, a symbol synchronization signal, and a FFT sampling clock from an OFDM modulator;specifically positioning null packets in a specific slot and before and after the specific slot based on the input frame synchronization signal, symbol synchronization signal and the FFT sampling clock; anddividing and outputting a transport stream according to the number of transmitted services;wherein a number of null packets or a number of PID packets is equal to or greater than a number of packets in slots used for transmitting services by interleaving, and a plurality of the frames form one superframe and the superframe is divided into slots.

A transmission apparatus for transmitting an OFDM signal with a frame structure in which a frame contains an integer number of transport stream packets and each frame contains a specification number of symbols, the transmission apparatus comprising a multiplexer for multiplexing a plurality of services, the multiplexer being configured to:ndivide, in time base, a frame into slots, each slot including a specific number of symbols; transmit a specific service using at least one of the slots;apply transmission channel coding to each specific service to transmit null packets or Picket Identifier (PID) packets before and after a boundary between slots transmitting different services, each PID packet not being related to the different services;input a frame synchronization signal, a symbol synchronization signal, and a FFT sampling clock from an OFDM modulator;specifically position null packets in a specific slot and before and after the specific slot based on the input frame synchronization signal, symbol synchronization signal and the FFT sampling clock; anddividing and output a transport stream according to the number of transmitted services;wherein a number of the null packets or a number of the PID packets is equal to or greater than a number of packets in slots used for transmitting services by interleaving, and a plurality of the frames form one superframe and the superframe is divided into slots.

A transmission apparatus for transmitting an OFDM signal using a transmission method that divides, in time base, a frame into slots, each slot including a specific number of symbols; transmits a specific service using at least one of the slots; and applies transmission channel coding to each specific service to transmit null packets or Packet Identifier (PID) packets before and after a boundary between slots transmitting different services, each PID packet not being related to the different services, the transmission apparatus, comprising:na first section that inputs a frame synchronization signal, a symbol synchronization signal, and a FFT sampling clock from an OFDM modulator;a second section that specifically positions null packets in a specific slot and before and after the specific slot based on the input frame synchronization signal, symbol synchronization signal and the FFT sampling clock; anda third section that divides and outputs a transport stream according to the number of transmitted services,wherein a number of null packets or a number of PID packets is equal to or greater than a number of packets in slots used for transmitting services by interleaving, and a plurality of the frames form one superframe and the superframe is divided into slots.