Patent ID: 7519102

Claim:
A spreading code assigning method in a direct sequence CDMA mobile communication system for transmitting a signal after spreading said signal doubly with a first spreading code in a first spreading code group and a second spreading code in a second spreading code group, said first spreading code having a same repetition period as an information symbol period in the communication system, said second spreading code having a longer repetition period than the information symbol period, said first spreading code and said second spreading code forming enlarging spreading codes for enlarging a band of a wide-band signal of the communication system, a rate of said enlarging spreading codes being higher than an information rate of the communication system, said method comprising the steps of: generating a common code associated with a base station group including more than one base station as said second spreading code, wherein said second spreading code functions as an identifier of said base station group; and storing said common code in base stations of said base station group and a mobile station belonging to said base station group to permit communication between the mobile station and the base station group.