Annual Results 2012

Principles of the WCDMA SystemScrambling Code Planning

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ObjectiveUpon 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)

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Chapter 1 WCDMA PSCsChapter 2 WCDMA PSC planning principleChapter 3 WCDMA PSC planning methodChapter 4 WCDMA PSC planning caseContents

4Scrambling codes introductionGOLD sequence.10ms ,or 38400 chips

Uplink scrambling codesThe 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 thatUplink scrambling codes are used to distinguish different UEs WCDMA Scrambling Codes

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5Downlink 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

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6Scrambling codes for downlink physical channels

Set 0Set 1Set 511Primary scrambling code 0Secondary scrambling code 1Secondary scrambling code 15Primary scrambling code 51116

Secondary scrambling code 5111615

8192 scrambling codes512 setsA primary scrambling code and 15 secondary scrambling codes are included in a set. Downlink Scrambling Codes

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Group 0Group 1Group 63

512 primary scrambling codes64 primary scrambling code groupsEach group consists of 8 primary scrambling codesDownlink Primary Scrambling Code GroupsPrimary scrambling codes for downlink physical channelsPrimary scrambling code 0Primary scrambling code 1Primary scrambling code 7Primary scrambling code 8*63

Primary scrambling code 63*87

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8Downlink Primary Scrambling CodesGroup0123456789101112131415PSC_1012825638451264076889610241152128014081536166417921920PSC_21614427240052865678491210401168129614241552168018081936PSC_33216028841654467280092810561184131214401568169618241952PSC_44817630443256068881694410721200132814561584171218401968PSC_56419232044857670483296010881216134414721600172818561984PSC_68020833646459272084897611041232136014881616174418722000PSC_79622435248060873686499211201248137615041632176018882016PSC_8112240368496624752880100811361264139215201648177619042032

1617181920212223242526272829303120482176230424322560268828162944307232003328345635843712384039682064219223202448257627042832296030883216334434723600372838563984208022082336246425922720284829763104323233603488361637443872400020962224235224802608273628642992312032483376350436323760388840162112224023682496262427522880300831363264339235203648377639044032212822562384251226402768289630243152328034083536366437923920404821442272240025282656278429123040316832963424355236803808393640642160228824162544267228002928305631843312344035683696382439524080

9Downlink Primary Scrambling Codes3233343536373839404142434445464740964224435244804608473648644992512052485376550456325760588860164112424043684496462447524880500851365264539255205648577659046032412842564384451246404768489650245152528054085536566457925920604841444272440045284656478449125040516852965424555256805808593660644160428844164544467248004928505651845312544055685696582459526080417643044432456046884816494450725200532854565584571258405968609641924320444845764704483249605088521653445472560057285856598461124208433644644592472048484976510452325360548856165744587260006128

4849505152535455565758596061626361446272640065286656678469127040716872967424755276807808793680646160628864166544667268006928705671847312744075687696782479528080617663046432656066886816694470727200732874567584771278407968809661926320644865766704683269607088721673447472760077287856798481126208633664646592672068486976710472327360748876167744787280008128622463526480660867366864699271207248737675047632776078888016814462406368649666246752688070087136726473927520764877767904803281606256638465126640676868967024715272807408753676647792792080488176

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Chapter 1 WCDMA PSCsChapter 2 WCDMA PSC planning principleChapter 3 WCDMA PSC planning methodChapter 4 WCDMA PSC planning caseContents

10step2step2/DSPStep3 UE UE1 UE

11Principle

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 WCDMA PSCs planning principle

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12WCDMA PSCs planning principleWhat is adjacent cell ?The adjacent cells can interfere with the primary 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.

13WCDMA PSCs planning principleWhat 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

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Chapter 1 WCDMA PSCsChapter 2 WCDMA PSC planning principleChapter 3 WCDMA PSC planning methodChapter 4 WCDMA PSC planning caseContents

15WCDMA PSC planning methodThe 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.

NOW THE LATTER IS RECOMMANDED

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Chapter 1 WCDMA PSCsChapter 2 WCDMA PSC planning principleChapter 3 WCDMA PSC planning methodChapter 4 WCDMA PSC planning caseContents

17In 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 keep reserve some PSCs for future network planning.

WCDMA PSC planning case

1712K12ij24.16R[]

Wireless Transmission Environment Scrambling Multiplexing Distance Dense urban area 4 km Common urban area 8.12 km Suburb 18 km Rural area 75 km

Cluster-Based Scrambling Multiplexing MethodAccording to scrambling planning principles, the following table gives recommended scrambling multiplexing distance values under four typical wireless transmission environments:

19WCDMA PSC planning case

20WCDMA PSC planning case

21WCDMA PSC planning case

22WCDMA PSC planning caseFor Example:

PSC #0 is allocated site A. So PSC #1, #2 & #3 can be allocated for other cells in site A .

If site X has three cells, then allocate three PSC 0,1,2 to the three cells. PSC #3 can be used for new cell added in future.

We recommend to use the remained PSC when add a new cell .

Thankyou!!

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