Cascadable diversity receiving system and method thereof

A method capable of performing combination steps for combining a plurality of weighted bit metric streams to output a final combined bit metric stream, each combination step comprising:

• receiving a RF signal;
• selecting a predetermined channel from the RF signal to generate an input analog signal;
• performing demapping according to the input analog signal to generate a weighted bit metric stream;
• and
• performing combination to generate a combined bit metric stream according to the weighted bit metric stream and a previous combined bit metric stream of a previous combination step, wherein performing combination further comprises:
• synchronizing the weighted bit metric stream with the previous combined bit metric stream;
• performing equivalent maximal ratio combination (MRC) to combine the weighted bit metric stream and the previous combined bit metric stream to generate a temporary bit metric stream;
• and
• selecting either the temporary bit metric stream or the weighted bit metric stream to be the combined bit metric stream.

A diversity receiving system comprising a plurality of cascading receivers for combining a plurality of weighted bit metric streams corresponding to a plurality of radio frequency (RF) signals to output a final combined bit metric stream from a final receiver in said plurality of cascading receivers, each receiver comprising:

• a tuner for receiving an RF signal and selecting a predetermined channel from the RF signal to generate an input analog signal;
• and
• a demapping and combining module coupled to the tuner and a previous demapping and combining module of a previous receiver for performing demapping according to the input analog signal of the tuner to generate a weighted bit metric stream and then performing combination to generate a combined bit metric stream according to the weighted bit metric stream and a previous combined bit metric stream of the previous receiver, wherein the demapping and combining module comprises:
• a channel estimating and equalizing unit for performing channel estimation and equalization to generate an equalized signal and a confidence value according to the RF signal;
• a bit metric generator coupled to the channel estimating and equalizing unit for demapping the equalized signal into bit metric stream and then performing weighting multiplication to the bit metric stream according to the confidence value to generate the weighted bit metric stream;
• and
• a combining circuit coupled to the bit metric generator and a previous combining circuit for performing combination to generate the combined bit metric stream according to the weighted bit metric stream and the previous combined bit metric stream from the previous combining circuit, wherein the combining circuit comprises:
• a sync unit for synchronizing the weighted bit metric stream with the previous combined bit metric stream;
• and
• a combining unit coupled to the sync unit for performing equivalent maximal ratio combination (MRC) to combine the weighted bit metric stream and the previous combined bit metric stream to generate a temporary bit metric stream as the combined bit metric stream.