Energy Resources. ( B. Pharmacy, 1st Year, Sem-II) Natural Resources
Lecture 7n
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3. CDMA on signal level I data A key A signal A data key key sequence A Real systems use much longer keys resulting in a larger distance between single code words in code space. 1 0 1 1 0 0 1 0 0 1 0 0 0 1 0 1 1 0 0 1 1 0 1 1 0 1 1 1 0 0 0 1 0 0 0 1 1 0 0 A d A k A s
4. CDMA on signal level II signal A data B key B key sequence B signal B A s + B s data key 1 0 0 0 0 0 1 1 0 1 0 1 0 0 0 0 1 0 1 1 1 1 1 1 0 0 1 1 0 1 0 0 0 0 1 0 1 1 1 B d B k B s A s
5. CDMA on signal level III A k (A s + B s ) * A k integrator output comparator output A s + B s data A 1 0 1 1 0 1 A d
6. CDMA on signal level IV integrator output comparator output B k (A s + B s ) * B k A s + B s data B 1 0 0 1 0 0 B d
7. CDMA on signal level V comparator output wrong key K integrator output (A s + B s ) * K A s + B s (0) (0) ?
27. GSM: elements and interfaces NSS MS MS BTS BSC GMSC IWF OMC BTS BSC MSC MSC A bis U m EIR HLR VLR VLR A BSS PDN ISDN, PSTN RSS radio cell radio cell MS AUC OSS signaling O
28. GSM: system architecture U m A bis A BSS radio subsystem MS MS BTS BSC BTS BTS BSC BTS network and switching subsystem MSC MSC fixed partner networks IWF ISDN PSTN PSPDN CSPDN SS7 EIR HLR VLR ISDN PSTN
29. System architecture: radio subsystem U m A bis A BSS radio subsystem network and switching subsystem MS MS BTS BSC MSC BTS BTS BSC BTS MSC