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3GPP-RAN Working Group 1 meeting #2 TSGW1#2(99)031Yokohama, Japan 22-25 February 1999

Agenda Item: 5

Source: Golden Bridge Technology, Inc.

Title: Uplink Common Packet Channel Advantages (A WP-CDMAfeature)

Document for: Discussion and Adoption of Uplink Common Packet Channel

Abstract:

This contribution touches on benefits of having the uplink common packetchannel versus the dedicated packet channel approach. We also discuss themethods of operation of the Common Packet Channel. The physical layer and the MACare also discussed in this contribution.

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WP-CDMA Distinguishing Features

1.Uplink 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 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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IP Traffic Types And CharacteristicsTable [1-4]

Attribute

IP Packets,WWW

browsingBest Effort

IP Packets,real time

audioInteractive

IP Packets,WWW

browsingPrioritized

IP Packets,WWW

browsingGuaranteed

IP Packets,WWW

browsingReal timestreaming

Direction Bi Bi Bi Bi UniPeak BitRate 2 Mbps 12 kbps 2 Mbps 2 Mbps 128 kbps

GuaranteedBit Rate 0 8 kbps 0 64 kbps 64 kbps

Average BitRate NA 4 kbps NA NA NA

SDU Sizespec (bits) 2 Ko 2 Ko 2 Ko 2 Ko 2 Ko

Max SDULoss Rate 10e-3 5% 10e-3 10e-3 5%

Max SDUerror rate 10e-9 10e-6 10e-9 10e-9 10e-6

Max SDUDelay 30s 80 ms 30s 30s 1s

Allocationpriority NA Dynamic

e.g. medium NA NA NA

Retentionpriority NA Dynamic

e.g. medium NA NA NA

TrafficHandlingpriority

NA NA Dynamice.g. high

Dynamice.g. medium

Dynamice.g. medium

[1] UMTSD 22.05[2] UMTS 22.60[3] TR 22.60[4] Tdoc SMG12 98 S 693

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What are the Information Transfer and InformationQuality Attributes of These Services?

Information Transfer AttributeConnection Mode Connectionless, Connection-

orientedTraffic type attribute CBR, VBR, ABR, UBRSymmetry attribute Bi, UniInformation transfer rate 12 kbps, 2 MbpsInformation Quality AttributeMaximum transfer delay 80 ms, 1 s, 30 sDelay variationBit Error Rate 10 –6, 10 –9

Error Characteristics Bursty, uniform

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How can the Common Air Interface be

Optimized for Packet Data Services?

The CAI should be able to support high bit rates (up to 2 Mbps),bursty, asymmetric, non-real time bearer capabilities

The CAI should support the connectionless mode as well as theconnection-oriented modes

The CAI should be able to support packet switching as well ascircuit switching transfer modes

The QoS on demand and flexibility to provision various informationquality attributes per connection (implications on physical layer,the MAC and DLC)

Minimize interworking functionality Maintain the same QoS in the wireline and wireless systems Minimize interference at the air interface Minimize resource requirement at the base station Optimize the IP protocol suite for the air interface Implementation of optimum bandwidth allocation at the air interface

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WP-CDMA Distinguishing Features

Common Packet Channel (All Rates)

• Common Packet Channel will transport all data rates up to and including 2.0489 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 Control Channel Structure

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F A BMOB ID F A BMOB

ID F A BMOB ID B

User i+1Packet MUser i

PacketM MUser i + 2

Packet 1User iPacket

E E User i+3Packet 1

EUser i+1Packet

MUser i + 3Packet 1

F = Free A = ACK B = BusyMob ID = Temp ID for Collision DetectionE = EndM = More

CPCHUL

WP-CDMA Common PacketChannel Uplink

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Packet 1 Packet 2 Packet 3 t iUser i

T inactivityPacket 1 Packet 2 t i+1

User i+1T inactivity

ti

Packet 1 t i+2

User i+2T inactivity

Short Term Circuit Assignment

Packet 2 Packet 3 Packet 4

t

Packet 1 Packet 2 Packet 3User n

i+1

nt

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WIMS 76.8 kbps, Uplink Indoor A, Soft Decision Viterbi, R=1/3, K=9 Power Control, ±1 dB @ 1.6 kHz

3.66E-02

1.28E-02

3.97E-03

1.33E-03

4.25E-04

3.33E-01

1.90E-01

1.00E-01

3.25E-02

8.24E-03

1.74E-03

1.81E-04

5.16E-02

1.82E-02

1.09E-02

4.38E-03

1.31E-03

3.50E-04

8.20E-05

3.99E-012.70E-01

1.15E-01

3.09E-02

4.14E-03

4.25E-04

2.56E-023.21E-02

1E-04

1E-03

1E-02

1E-01

1E+00

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Eb/No, dB

BE

R

No APC, No Ant. Diversity

APC, No Ant. Diversity

No APC, Ant. Diversity

APC, Ant. Diversity

1.73E-03

Closed Loop Power ControlCourtesy of AT&T Labs

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3.416

1.419

Ri 19

Ri 10

Ri 1

13.251.25 li8

0 2 4 6 8 10 12 141

1.5

2

2.5

3

3.5

Packet Length in Kbyte

Capacity RatioP-S/C-S

Channel inactivity = 50 ms

Channel inactivity = 500 ms

Channel inactivity = 1 s

Advantages of Statistical Multiplexing

144 kbpsCapacity Ratio Versus Packet Length in Kbyte

PB=2%100% Duty Cycle

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384 KbpsCapacity Ratio Versus Packet Length in Kbyte

PB=2%100% Duty Cycle

8.176

2.85

Ri 19

Ri 10

Ri 1

272.5 li8

0 5 10 15 20 25 302

3

4

5

6

7

8

9

Packet Length in Kbyte

Capacity RatioP-S/C-S Channel inactivity time = 1 s

Channel inactivity time = 500 ms

Channel inactivity time = 50 ms

Advantages of Statistical Multiplexing

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2048 KbpsCapacity Ratio Versus Packet Length in Kbyte

PB=2%100% Duty Cycle

42.84

7.427

Ri 19

Ri 10

R i 1

425 l i

8

5 10 15 20 25 30 35 40 455

10

15

20

25

30

35

40

45

Channel inactivity time = 1 sChannel inactivity time = 500 ms

Channel inactivity time = 50 ms

Packet Length in Kbyte

Capacity RatioP-S/C-S

Advantages of Statistical Multiplexing

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1 ms .25 ms

I

Q

Data/ControlPreambleramp-up

N x TBD ms

UL-CPCH Burst Structure

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.625 ms, 10 x 2k bits (k=0,….6)

N data bit 1Data

N data bit 1Data

PilotN pilot bits

PilotN pilot bits

TPCNTPC bits

TPCNTPC bits

RINRI bits

RINRIbits

CD bitsNCD

UL-CPCH

UL-CPCH

UL-CPCH

UL-CPCH

I

Q

I

Q

Slots 0

Slots 1

UL-CPCH Slot Structure

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.625 ms, 10 x 2k bits (k=0,….6)

N data bit 1Data

PilotN pilot bits

TPCNTPC bits

RINRI bits

UL-CPCH

UL-CPCH

I

Q

Slot #1 Slot #2 Slot #i Slot #16

Tf = 10 ms

UL-CPCH Frame Structure

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Data

Power Control

N x TBD ms

1 ms .25 ms

DL-CCCH

UL-CPCH

CCCH: Common Control ChannelCPCH: Common Packet Channel

L1ACK

TBD ProcedureBased

Overall Protocol Operation

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DL-CCCH

pd TT

BS F 0 1 2 3 4 5 6 7

2.5 ms 8 mini-slots

ACK CD

CD

TBD

F

1.875 ms

1ms 250 s Slot 0625 s

BS

MSUL-CPCH

Collision Feedback Delay Cycle

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Overall Protocol Operation

DL CCCHACK/NAK

1.25 ms

LIACK

UL CPCHCD CD

CDCD PC ARQ

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Collision Probability

Pc= P c 2 P(2,T) + P c 3 P(3,T)+ P c 4 P(4,T) + P c 5P(5,T)+ …

Where:

T = Tp+Tcc

Tcc = contention cycleTp = Packet length

P c m Nm / Ms

Ms = Ns x Nc

Ns = number of mini-slotsNc = Number of available signature codesNm = m / {2x(m-2))}

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Throughput Delay Analysis with Re-transmissions dueto Collision and Errors and Congestion Control

Throughput Delay of an M./M/1 queue with the congestion control [1]

E [ T] = 1/(1- e -) = (1- e -)

E [n] =

Collisions Re-transmissions due to errors Congestion Control

= (1- e -)(1-Pc) / NARQE [ T] = NARQ /{(1- e -)(1-Pc)}

[1] Mischa Schwartz, “Computer Communications Networks”

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Throughput Performance of DSMAImpact of Low Collision Feedback Delay

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Performance Advantages of UplinkCommon Packet Channel

(Summary-1)

Proven improved throughput performance for short bursty traffic and high peak rate

•Sample pt: 384 kbps, L=4 Kbyte, Access overhead =500 ms, P B = 2% Throughput improvement Ratio = 5

•UDD Services

Improved delay performance of M/M/1 (packet switched) overM/M/n (circuit switched) for longer packets

Common Packet Channel approach requires an order of magnitudeless BS resources (modems) as compared to Short Term CircuitAssignment.

• M/M/10 requires 10 times more modems in the BS as compared to M/M/1

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• Statistical multiplexing advantages for bursty traffic

• Less delay M/M/1 versus M/M/n

• Resource minimization and less hardware complexity

• Facilitation of higher peak rates

Performance Advantagesof CPCH-UL

• Queuing time & transmission time

• Limitations of circuit switching trunking efficiency

(Summary-2)

• Optimum prioritization scheme

• Optimum bandwidth allocation in a mixed circuit-switched/packet switched air interface operation in short time window (frame by frame basis)