For a WCDMA system, frequency planning is not required for a WCDMA system, but scrambling code planning for neighborhood cells is necessary. With scrambling code planning, the reuse distance between adjacent cells using the same scrambling code can be determined and different cells can be distinguished. The planning method based on scrambling code groups can be adopted for mobile station to quickly search cells. One principle for scrambling code planning is that overlapping cells in a network cannot use the same primary scrambling codes. For scrambling code planning, the reuse distance between adjacent cells using the same scrambling code can be determined and different cells can be distinguished. The planning method based on scrambling code groups can be adopted for mobile station to quickly search cells. One principle for scrambling code planning is that overlapping cells in a network can not use the same primary scrambling codes.