| 摘要 |
A transmitter communicating data using Orthogonal Frequency Division Multiplexed (OFDM) symbols including plural sub-carrier symbols in the frequency domain for modulating with data to be carried. The transmitter includes a modulator to receive data symbols from a first data pipe according to a first communications channel, to receive data symbols from a local service insertion data pipe according to a local communications channel, and to modulate the sub-carrier signals of the OFDM symbols with either the data symbols from the first data pipe or from both the first data pipe and the local service insertion pipe; modulation from the first data pipe maps the data symbols is according to a first modulation scheme, and modulation from the first data pipe and the local service insertion pipe maps the data symbols is according to a second modulation scheme. |
