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待解决问题
关于secondary scrambling code（辅扰码）的作用
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提问者：jingsuxuyi
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提问时间：2014-2-20 15:48
哪位大侠给解释一下secondary scrambling code（辅扰码）的作用，并且是在什么情况使用的，谢谢。我知道中国联通目前还没有使用。而且主扰码在下行是区分小区的，能不能详细地解释一下secondary scrambling code（辅扰码），多谢
The 512 primary scrambling codes are expected to be enough from the cell planning perspective, especially as the secondary scrambling codes can be used in the case of beam steering as used on DCHs. This allows the capacity to evolve with adaptive antenna techniques without consuming extra primary scrambling codes and causing problems for downlink code planning.
The secondary downlink scrambling codes can be applied with the exception of those common channels that need to be heard in the whole cell and/or prior to the initial registration. Only one scrambling code should be used per cell or sector to maintain the orthogonality between different downlink code channels. With adaptive antennas the beams provide additional spatial isolation and the orthogonality between different code channels is less important. However, in all cases the best strategy is still to keep as many users as possible under a single scrambling code to minimize downlink interference. If a secondary scrambling code needs to be introduced in the cell, then only those users not fitting under the primary scrambling code should use the secondary code. The biggest loss in orthogonality occurs when the users are shared evenly between two different scrambling codes.
The secondary downlink scrambling codes can be applied with the exception of those common channels that need to be heard in the whole cell and/or prior to the initial registration. Only one scrambling code should be used per cell or sector to maintain the orthogonality between different downlink code channels. With adaptive antennas the beams provide additional spatial isolation and the orthogonality between different code channels is less important. However, in all cases the best strategy is still to keep as many users as possible under a single scrambling code to minimize downlink interference. If a secondary scrambling code needs to be introduced in the cell, then only those users not fitting under the primary scrambling code should use the secondary code. The biggest loss in orthogonality occurs when the users are shared evenly between two different scrambling codes.
回答时间：2014-2-21 09:57
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