| 摘要 |
PURPOSE: A demodulator using an STTD(Space Time black coding based Transmit antenna Diversity) decoder for spread spectrum communication is provided to include the STTD decoder for supporting an STTD decoding, and to use one multiplier and one integrator in the STTD decoder, so as to reduce the size and easily perform a variable signal processing by controlling operations of the STTD decoder according to an STTD mode. CONSTITUTION: A code generator(203) is composed of many spread code generators and OVSF(Orthogonal Variable Spreading Factor) code generators. A complex despreader(302) is connected to a channel predictor(213) for outputting many predicted channels, and complex-despreads spread spectrum signals which are sampled at a low speed by using spread codes. A backward channelizer(305) backward-channelizes the despread signals by using OVSF codes. A summer(307) integrates output signals of the backward channelizer(305) as symbol units according to a chip rate enable signal, and outputs the integrated signals. Serial to parallel converters(310,311) store the integrated symbol values of the summer(307), and divide even-numbered and odd-numbered symbols as two-symbol units, then output the divided symbols. An STTD decoder(315) selectively receives the predicted channels and signals of two symbols buffered in the serial to parallel converters(310,311), to perform a complex multiplication, and performs a channel distortion compensation and an STTD decoding. A deskew buffer(321) stores signals decoded in the STTD decoder(315) by arranging time. |
