| 摘要 |
A CDMA communication method capable of providing a multi-rate user with high quality transmission using a spreading sequence selected from sequences which consist of multilayer sequences arranged in a hierarchical tree structure. A higher level sequence C16(1) and its inverted sequence +E,ovs C+EE 16(1) are included in its lower level sequences {C32(1), C32(2)} and {C64(1), C64(2), C64(3), C64(4)}, for example, and a sequence from a higher level is selected to transmit a higher rate data: The C16(1) is used to transmit data whose peak rate is twice the peak rate of the data transmitted using its lower level sequences {C32(1), C32(2)}, and four times (=22) that of the data transmitted using the sequences {C64(1), C64(2), C64(3), C64(4)}. The C16(l), however, cannot be selected if any one of its lower level sequences {C32(1), C32(2)} and {C64(1), C64(2), C64(3), C64(4)} are already being used. This makes it possible for all the spreading sequences of simultaneous multi-rate users to be orthogonal at any transmission rate.
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