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Synchronisation
Codes
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Channelisation
Codes
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Scrambling
Codes, UL
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Scrambling
Codes, DL
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Type
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Gold Codes
Primary Synchronization Codes (PSC) and Secondary Synchronization Codes (SSC)
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Orthogonal Variable Spreading Factor (OVSF) codes
sometimes called
Walsh Codes
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Complex-Valued Gold Code Segments (long) or Complex-Valued S(2) Codes (short)
Pseudo Noise (PN) codes
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Complex-Valued Gold Code Segments
Pseudo Noise (PN) codes
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Length
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256 chips
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4-512 chips
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38400 chips /
256 chips
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38400 chips
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Duration
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66.67 µs
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1.04 µs -
133.34 µs
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10 ms / 66.67 µs
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10 ms
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Number of codes
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1 primary code / 16 secondary codes
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= spreading factor
4 ... 256 UL,
4 ... 512 DL
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16,777,216
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512 primary / 15 secondary for each primary code
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Spreading
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No, does not change bandwidth
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Yes, increases bandwidth
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No, does not change bandwidth
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No, does not change bandwidth
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Usage
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To enable terminals to locate and synchronise to the cells' main control channels
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UL: to separate physical data and control data from same terminal
DL: to separate connection to different terminals in a same cell
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Separation of terminal
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Separation of sectors
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