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Published byThomas Pitts Modified over 9 years ago
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2 WP-CDMA Distinguishing Features 1. Reverse Link Common Packet Channel (All Rates) Common Packet Channel will transport all data rates up to and including 2.048 Mbps. Constant Power Level Preamble with 16 possible sequences Closed Loop Power Control, Preamble Ramp-up mechanism Fast L1 ACK mechanism (within 250 micro-seconds) Collision Detection with Low Feedback Delay (2 ms) Downlink Common Power Control Structure 2. Common control channel in the Down Link 3. Intra-frequency Hard Handover 4. Quick Handover 5. Structure of the WP-CDMA CCPCH (Common Control Physical Channel) 6. Multi-code option for Higher Rates The relationship between the VSF and number of multi-codes is the subject of further study TM Common Pilot for coherent demodulation Adjustable Power SCH1 And SCH2 for faster initial cell search 7. Higher APC Rates 8. Removal of Link Maintenance Channel
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3 WP-CDMA Distinguishing Features Structure of the WP-CDMA CCPH (Common Control Physical Channel) The WP-CDMACCPCH is based upon the Ad-Hoc S parameterized Perch channel with the following modifications: The primary SCH and secondary SCH are multiplexed onto the I and Q channel respectively. The power of the primarySCH is controlled by parameter P3. This is the unmodulated primary sync code as found in WCDMA/NA, UTRA, and ARIB. The power of the secondarySCH is controlled by parameter P4. This is the secondary sync code scheme as specified inUTRA. The Common Pilot is Time Multiplexed with Data. The dedicated pilot is supported with the following parameters: C2, L2 and P2. The dedicated pilot is time multiplexed with the Traffic Channels. (Feature 5)
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4 CCPCH Common Pilot Parameters C1 = Channelization codeof common Pilot L1 = Length of common Pilot P1 = Power of common Pilot PilotDataPilotData I Secondary Sync Channel P4 = Power of Secondary Sync Channel Q Primary Sync Channel P3 = Power of Primary Sync Channel Structure of the WP-CDMA CCPCH.
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5 Acquisition Performance (first step) in Rayleigh Fading and AWGN Channels
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6 Step 2 Synchronization Process. Probability of Missed Detection for a Single Frame (10 ms) Observation Interval. (A) Imperfect channel Estimates (B) Perfect Channel Estimates
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9 WP-CDMA Performance Advantages Due to Adjustable Higher Power Synch Channel Handover Performance Fast searcher, fast neighbor detection for idle and active soft or hard handover De-correlation length for Vehicular = 20 m, v 1 = 250 km/h, t 1 =288 ms, v 2 =125 km/h, t 2 = 576 ms 10 cells x 500 ms = 5 s (Without TM Common Pilot) 10 cells x 100 ms = 1000 ms (With TM Common Pilot WP-CDMA) Relevant to quick HO, idle and active HO (cold start cases) BS1BS2BS3BS4BS5BS6BS7 t 625 sec. 1 slot MF t S SSSSSS
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10 Performance Advantages due to Stronger TM Common Pilot and Adjustable Power SCH1/SCH2 Better Channel Estimates (.7 dB gain) Faster System Access (SNR=10 dB, T access = 40 ms) Faster neighbor detection and cell search (handover and quick handover) Quick re-acquisition capability and quick cell search capability (idle handover procedure) facilitates minimization of the observation window in the battery saving mode of operation.
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