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3GPP-RAN Working Group 1 meeting #2 TSGW1#2(99)035Yokohama, Japan 22-25 February 1999

Agenda Item: 5

Source: Golden Bridge Technology, Inc.

Title: Advantages of Modified Ad-Hoc S approach ( A WP-CDMA feature)

Document for: Discussion and adoption of the modified Ad-Hoc Sapproach

Abstract:

This contribution discusses the advantages ofmodifying the Ad-Hos S approach in that the powerassociated with SCH1 and SCH2 can be adjustedto improve the acquisition performance. ModifiedAd-Hoc S approach was adopted by the WP-CDMAcommittee as the structure of the common controlphysical channel. Note that SCH1 and SCH2 areI/Q multiplexed.

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WP-CDMA Distinguishing Features

1. Reverse Link Common Packet Channel (All Rates)

Common Packet Channel will transport all data rates up toand 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 Link3. Intra-frequency Hard Handover4. Quick Handover5. 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 Rates8. Removal of Link Maintenance Channel

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WP-CDMA Distinguishing FeaturesStructure of the WP-CDMA CCPH

(Common Control Physical Channel)

The WP-CDMA CCPCH is based upon the Ad-Hoc S parameterized Perch channelwith the following modifications:

•The primary SCH and secondary SCH are multiplexed onto the I and Q channel respectively.

•The power of the primary SCH is controlled by parameter P3. This is the unmodulated primary sync code as found in WCDMA/NA, UTRA, and ARIB.

•The power of the secondary SCH is controlled by parameter P4. This is the secondary sync code scheme as specified in UTRA.

•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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CCPCH

Common Pilot ParametersC1 = Channelization code of common PilotL1 = Length of common PilotP1 = Power of common Pilot

Pilot Data Pilot Data

I

Secondary Sync ChannelP4 = Power of Secondary Sync ChannelQ

Primary Sync ChannelP3 = Power of Primary Sync Channel

Structure of the WP-CDMA CCPCH.

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350

1

xr120i 1

xr3i 1

xgi 1

200 xr120i 0

0 2 4 6 8 10 12 14 16 18 201

10

100

1 103

SNR (dB)

Tim

e (m

sec)

120 km/hcase

3 km/hcase

AWGNchannel

Acquisition Performance (first step) in Rayleigh Fading and AWGNChannels

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2 0 2 4 6 8 10 12 14 16 181 10

3

0.01

0.1

1

SNR (dB)

Pmis

s

Gaussian

Channel(A)(B)

120 Km/h(A)(B)

3 Km/h(A)(B)

Step 2 Synchronization Process. Probability of Missed Detection for a Single Frame (10 ms)Observation Interval. (A) Imperfect channel Estimates (B) Perfect Channel Estimates

72 1 0 1 2 3 4 5 6 7 8 9 10

1 104

1 103

0.01

0.1

1

Received Eb/N0 in dB

BER

Pro

babi

lity

M=1M=2M=4M=6M=8M=16IdealQPSK

Performance Comparison Of MHeader Symbols Per Slot For QPSK

Sigh

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WP-CDMA Performance Advantages

Due to Adjustable Higher Power Synch

Longest Standby Time

Most efficient sleep mode of operation (long standby time due to lowest observationwindow)

The MS acquires quickly (few tens of milliseconds) without any need for continuouspilot tone in the downlink direction.

The wake-up time is dedicated to idle handover procedure, reading messages from theBCCH and PCH.

Quick re-acquisition capability and quick cell search capability (idle handoverprocedure) facilitates minimization of the observation window in the battery savingmode of operation.

Extremely low duty cycles can be accommodated to maximize the standby time.

Wake-up time Sleep time

Acquisitiontime

Idle HOHO

ReadingmessageThis figure is not

drawn to scale

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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,v1 = 250 km/h, t1=288 ms, v2=125 km/h, t2= 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)

BS1 BS2 BS3 BS4 BS5 BS6 BS7

t625 sec.

1 slot

MF

t

S S S S S S S

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Performance Advantages due to Stronger TM Common Pilotand Adjustable Power SCH1/SCH2

Better Channel Estimates (.7 dB gain)

Faster System Access (SNR=10 dB, Taccess = 40 ms)

Faster neighbor detection and cell search (handover and quickhandover)

Quick re-acquisition capability and quick cell search capability(idle handover procedure) facilitates minimization of theobservation window in the battery saving mode of operation.