PURPOSE: To compress the circuit scale of a demodulation part and to reduce power consumption by performing demdoulation on an orthogonal spread code system by fast Hadamard transformation by using a Walsh function.
CONSTITUTION: An information bit is sectioned at every K bits by an encoder 1, and (r) combinations of the Walsh function are selected from (n) Walsh functions in accordance with 2 states of the information bit, and the Walsh functions selected at a circuit 2 are generated simultaneously with designated polarity, and they are added at a circuit 3, and spread by a PN code to allocate a code division multiplex channel from a circuit 5 at a circuit 4, and it is transmitted by transforming to the band of a carrier wave from a circuit 7 at a circuit 6. A received signal is transformed to a baseband area by the local carrier wave of a circuit 12 at a circuit 11, and reverse spread is performed by the local PN code of a circuit 14 at a circuit 13, and the fast Hamadard transformation in (n) symbol unit is performed at a circuit 15, and it is decided what Walsh function is combined in which polarity, and information is transformed to the one of K bits by performing an operation opposite to the one of the encoder 1 at a decoder 16.
KATO OSAMU
HONMA KOICHI
| JPH0435332A | 1992-02-06 |