Uplink Control Signal Detection via Cyclic Shift Spreading

The patent applies parameter changes by utilizing different cyclic shift values of a base sequence as spreading codes in the frequency domain. Instead of using complex spreading matrices or multiple-dimensional spreading, the system varies a single parameter (cyclic shift amount) to generate multiple orthogonal spreading codes, thereby improving detection reliability while keeping the transmission system relatively simple.

The patent segments the frequency domain into multiple subcarriers and assigns different cyclic shifts of the base sequence to different control signals. This segmentation allows multiple control signals to be transmitted simultaneously on the same time resources but different frequency resources, improving reliability through frequency diversity without requiring complex multi-dimensional spreading.

The patent employs dynamics by using cyclic shifts that adapt to the time-varying channel characteristics. The base sequence is cyclically shifted by different amounts for different control signals, and this cyclic shift property remains stable even in time-varying channels because the cyclic shift operation commutes with the channel time-variation. This allows multiple control signals to maintain orthogonality while being transmitted simultaneously in the same radio resource.

The patent uses copying by creating multiple copies of the same base sequence with different cyclic shifts. These copied sequences (different cyclic shifts of the base sequence) serve as orthogonal spreading codes for different control signals. Since they are derived from the same base sequence through deterministic cyclic shifts, they maintain perfect orthogonality even in time-varying channels, enabling multiple control signals to be transmitted simultaneously without interference.