Huawei WCDMA Primary Scrambling Code Planning

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Huawei WCDMA/UMTS Primary Scrambling Code Planning

Transcript of Huawei WCDMA Primary Scrambling Code Planning

Course code Course nameISSUE 1.0
Upon completion this course, you will be able to:
Understand the principles for cell primary scrambling codes planning in WCDMA network
Understand how to plan the cell primary scrambling codes (PSC)
Internal Use
Internal Use
Uplink scrambling codes
The codes which are used for scrambling the uplink physical channels can be either long or short type.
224 long and 224 short uplink scrambling codes.
Uplink scrambling codes are assigned by higher layers.
Because uplink scrambling codes with a great number are allocated by RNC, we do not give our attention for that
Uplink scrambling codes are used to distinguish different UEs
WCDMA Scrambling Codes
Downlink scrambling codes
For downlink physical channels, a total of 218-1 = 262,143 scrambling codes can be generated.
Only scrambling codes k = 0, 1, …, 8191 are used.
8192 codes are divided into 512 groups, each of which contains 16 scrambling codes.
The first scrambling code of each group is called primary scrambling code (PSC), and the other 15 ones are secondary scrambling codes (SSC).
The 512 PSCs are also divided into 64 groups, each of which contains 8 PSCs.
Downlink PSC is used to distinguish the different cells.
It has to be considered carefully
WCDMA Scrambling Codes
A primary scrambling code and 15 secondary scrambling codes are included in a set.
Downlink Scrambling Codes
Set 0
Set 1
8192 scrambling codes
Each group consists of 8 primary scrambling codes
Downlink Primary Scrambling Code Groups
Primary scrambling codes for downlink physical channels
Primary scrambling code 0

Internal Use
The intra-frequency other cells can not use the same PSC as the primary cell because of the interference!
Which cells are included in the intra-frequency other cells?
- Adjacent cell
- Neighboring cell
What is neighboring cell ?
Adjacent cells of a primary cell already include neighboring cells.
In terms of primary cell, it can receive pilot signals from other intra-frequency cells at the border of the cell.
These pilot signals may be stronger or weaker than that of UE access level.
If the pilot signal at the border of the primary cell is stronger than that of UE access level, this cell is (or probably is) the neighboring cell of the primary cell.
Internal Use
What is non neighboring cell ?
These cells without interference to the primary cell are regarded as non neighboring cells, which can use the same PSCs as this primary cell
Internal Use
Internal Use
WCDMA PSC palnning method
The cell PSCs can be planned by either of the following two methods:
Primary cell uses different PSCs from the neighboring cells, with the PSCs of the primary cell and those of the neighboring cells belonging to the same scrambling code group.
Primary cell uses different PSCs from the neighboring cells, with the PSCs of the primary cell and those of the neighboring cells belonging to different scrambling code groups.
Internal Use
In general, one site can support 3 intra-cells in actual network. So one PSCs group can be divided into (8 PSCs every group) 2 subgroups (4 PSCs every subgroup)
512 PSCs can be divide into 128 subgroups. The first PSC that stands for the subgroup should take part in the site PSC planning, the other PSCs of the subgroup are allocated to the cells of this site.
We must remain partially PSCs in order to network evolution.
WCDMA PSC planning case
Internal Use
WCDMA PSC planning case
0# PSC is allocated site 0,so 1, 2 and 3# PSC is allocated site 0,too.
If site 0 has three cells, then allocate three 0,1,2#PSC to three cells and 3# PSC is remained to add a new cell.
we recommend to use the remained PSC when add a new cell .
Internal Use