Cell-Specific Scrambling for Uplink Interference Mitigation

The patent applies local quality by making the spreading sequence cell-specific rather than system-wide. Each cell is assigned a unique spreading sequence (e.g., based on cell ID), so that while multiple cells can reuse the same time-frequency resources, each cell's signals are locally distinguishable. This resolves the contradiction by maintaining resource utilization through reuse while eliminating inter-cell interference through local differentiation.

The patent changes the parameter of the spreading sequence from a common system parameter to a cell-specific parameter. By varying the spreading sequence parameter according to cell identity (e.g., using different orthogonal codes or cyclic shifts per cell), the system enables multiple cells to transmit simultaneously on the same resources without interference, thus improving resource utilization while maintaining demodulation performance.

The patent implements local quality by assigning cell-specific spreading sequences that are uniquely identified at each cell. For cell edge users, this means their signals are tagged with their home cell's specific sequence, enabling the base station to precisely detect and distinguish these weak signals from interfering signals of other cells, thereby maintaining high detection precision while supporting high system capacity.

The cell-specific spreading sequence acts as an intermediary that carries cell identity information. This intermediary enables the base station to differentiate between signals from different cells without requiring additional signaling or changing the physical transmission resources, thus maintaining detection precision while supporting high system capacity.

The patent applies local quality by making spreading sequences cell-specific rather than system-wide. Each cell uses spreading sequences that are locally unique (e.g., derived from cell ID), which maintains simple device complexity since the same generation algorithms are used throughout, while ensuring signal integrity by preventing inter-cell interference through local differentiation.

The patent segments the system-wide spreading sequence space into cell-specific segments. Instead of one common sequence pool for all cells, each cell is assigned its own segment of the sequence space (e.g., different orthogonal codes or cyclic shift ranges). This segmentation reduces device complexity by using simple repetition of cell-specific patterns while maintaining signal integrity through isolation of interference between segments.