DEVICE AND METHOD FOR RADIO RECEPTION

摘要

PROBLEM TO BE SOLVED: To eliminate the need for a large-scale correlation circuit adaptable to a high spreading rate by performing correlation operation with a code with a low spread rate and obtaining a reverse spread signal of a receive signal with a high spread rate through multiplying and adding operations. SOLUTION: A signal received by an antenna 101 is down-converted by an RF part 102 and converted into a digital base band signal by an A/D conversion part 103. The base band signal is multiplied by a scramble code L(i) by a multiple 105 and multiplied by a spreading code Cm(i) as a hierarchical orthogonal code through a multiplier 105. Namely, a reverse spread process is performed by using a spread code with a low spread rate. The signal after the reverse spread processing is supplied to an adder 106 to find an integral value, thereby obtaining a reverse spread signal with a low spread rate. The reverse spread signal with the low spread rate is stored in a buffer 107, and multiplied and added by a multiplied adder 108 in order to obtain a reverse spread signal Rkm+1. At this time, code order information found from the spreading rate decided by an SF decision circuit 10 is sent.