C30-WG3-20040920-006

Title: Active Set Membership and Finger Assignment Rules for the CDM based

transmissions in the 1xEV-DO BCMCS Evaluation Methodology Abstract: This contribution provides active set membership and finger assignment rules

for the CDM base transmissions in the 1xEV-DO BCMCS Evaluation Methodology.

Source:

Eddy Kwon, Younsun Kim, Jin-Kyu Han and Donghee Kim

eddykwon@samsung.com

Samsung Electronics Co., Ltd.

Tel: +82-31-279-5087

Mobile: +82-16-9530-5087

Date: September 20, 2004 Recommendation: Discuss and adopt.

Notice

Samsung Electronics grants a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner's name any Organizational Partner's standards publication even though it may include all or portions of this contribution; and at the Organizational Partner's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner's standards publication. Samsung Electronics is also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partners standard which incorporates this contribution. This document has been prepared by Samsung Electronics to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on Samsung Electronics. Samsung Electronics specifically reserves the right to amend or modify the material contained herein and to any intellectual property of Samsung Electronics other than provided in the copyright statement above.

cdma2000 is the trademark for the technical nomenclature for certain specifications and standards of the Organizational Partners (OPs) of 3GPP2. Geographically (and as of the date of publication), cdma2000 is a registered trademark of the Telecommunications Industry Association (TIA-USA) in the United States

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1 Introduction

During the last Osaka meeting, WG3 discussed the active set membership rules for the

CDM based transmissions described in the 1xEV-DO BCMCS evaluation methodology

proposed by Qualcomm [1]. It was concluded that we need to investigate and modify the

active set membership and finger assignment rules for the CDM based transmissions in

broadcast scenario.

This contribution studies the performance of TIA-1006 broadcast with various T_ADD

values and maximum numbers of fingers at the mobile station. We then propose an active

set membership and finger assignment rules for the CDM based transmissions 1xEV-DO

evaluation methodology.

2 Studies on the Performance of TIA-1006 Broadcast with various T_ADD values and maximum numbers of fingers

In this section, we study the performance of TIA-1006 broadcast with various T_ADD values

and maximum numbers of fingers at the mobile station through the system level

simulations.

2.1 Simulation Setup Most of simulation assumptions follow 1xEV-DO Broadcast Multicast Service Evaluation

Methodology Proposal proposed by Qualcomm [1]. The summary of the simulation setup is

as follows.

- 2 rings, 3 sectors, 57 sectors total

- Total 5,700 mobiles were dropped.

- Wrap around technique is used so as any mobile to have sectors up to two tiers.

- Site to site distance: 2.0 km

- Maximum best path loss limit: 138 dB

- Maximum C/I limit: 13.5 dB

- Both single and dual receiver antennas (uncorrelated)

- Simulated Transmission Formats

o 307.2 kbps (EP size: 1024, Slot length: 2) o 409.6 kbps (EP size: 2048, Slot length: 3) o 614.4 kbps (EP size: 1024, Slot length: 1)

- Mixed channel models: The channel models A through E with the portion of 0.3,

0.3, 0.2, 0.1, and 0.1 for channel model A, B, C, D, and E, respectively.

- SINR-PER Modeling

o The SINR-to-PER modeling is based on the quasistatic method with fudge

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factors, described in the evaluation methodology [1].

o The SINR for each BCMCS packet is calculated as in [2]. It is used to look up the corresponding PER vs. average Ec/Nt for the specific transmission

format. A packet erasure event is then generated based on the PER value.

o The AWGN curves shown in Figure 1 are based on link-level simulations that incorporate the actual modeling and puncturing used.

AWGN PER curves for the TIA-1006 Broadcast Data Rates

0.001

0.01

0.1

1

-6 -5 -4 -3 -2 -1 0

Ec/No [dB]

PE

R

307.2 kbps (1024, 2 slots) 409.6 kbps (2048, 3 slots) 614.4 kbps (1024, 1 slots)

Figure 1. AWGN PER curves

o Doppler penalties are used as in Table 1 [3].

Table 1. Doppler Penalties

Doppler Offset (dB) based on

Channel Model Speed Data Rate

(kbps)

Payload

Size # of Slots

3 kmph > 3 and kmph

> 30

kmph

307.2 1024 2 0.0 0.5 1.0

409.6 2048 3 0.0 0.5 1.0

614.4 1024 1 0.0 0.5 1.5

819.2 4096 3 0.0 0.5 1.5

o The outer Reed-Solomon code is used as described in [4].

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2.2 Simulation Results

2.2.1 Performance vs. T_ADD values

In this section, we investigate the performance of TIA-1006 broadcast according to different

T_ADD values. Distribution of the number of members in the active set is shown in Figure 2.

The number of active set members is not limited in the Figure 2, to see its trend even

though it might not be feasible. As expected, the number of active set members increases as

T_ADD decreases. We can observe that about 88 % of mobiles have only one or two sectors

in their active set with T_ADD of 9 dB while about 87 % of mobiles have more than three

sector in their active set with T_ADD of 21 dB.

Distribution of the number of members in the active set vs. T_ADD

0%

10%

20%

30%

40%

50%

60%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15number of members in the active set

T_ADD=-9dB T_ADD=-12dB T_ADD=-15dBT_ADD=-18dB T_ADD = -21 dB

Figure 2. Distribution of the number of members in the active set

In the following simulation results in this section, we assume a maximum of 6 members in

the active set and a maximum of ic fingers per member of the active set, where ic is

determined by the multi-path model as described in Table 2. Therefore, utmost {6, 18, 12, 6,

6} resolvable fingers are allocated by the RAKE receiver for channel model A, B, C, D and E,

respectively.

Table 2. Maximum number of resolvable fingers per active set member

Channel model Multi-path model ic

A Pedestrian A 1

B Pedestrian B 3

C Vehicular A 2

D Pedestrian A 1

E Rician/AWGN 1

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Figure 3 shows the performance results on TIA-1006 broadcast at 307.2 kbps according to

different T_ADD values with single antenna receiver and without RS coding. We can observe

that the coverage dramatically increases as T_ADD decreases. T_ADD of 21 dB achieves better than 98.8 % at 1 % PER without RS code.

Performance Results of TIA-1006:307.2 kbps (EP: 1024, 2 slots), Single Rx antenna, No RS code, Mixed DV Channel,Maximum of 6 members in the active set, utmost {6, 18, 12, 6, 6} resolvable fingers

for channel model A, B, C, D, E

0.900.910.920.930.940.950.960.970.980.991.00

-3 -2.5 -2 -1.5 -1 -0.5 0x = log10(FER)

Pr[F

ER

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Total average Ec/Nt for all the mobiles:307.2 kbps (EP: 1024, 2 slots), Mixed DV Channel, Maximum of 6 members

in the active set, utmost {6, 18, 12, 6, 6} resolvable fingersfor channel model A, B, C, D, E

0

1

2

3

4

5

6

-9 dB -12 dB -15 dB -18 dB -21 dB - infinityT_ADD

[dB]

Figure 4. total average combined Ec/Nt for all the simulated mobiles

Distribution of Average Combined Ec/Nt of TIA-1006:307.2 kbps, Single Rx antenna, Mixed Channel, Maximum of 6 members in the

active set, utmost {6, 18, 12, 6, 6} resolvable fingers for channel model A, B, C, D, E

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

-6 -4 -2 0 2 4 6 8 10 12

Average combined Ec/Nt [dB]

cdf

T_ADD= -9dB

T_ADD= -12dB

T_ADD= -15dB

T_ADD= -18dB

T_ADD= -21dB

T_ADD= -infinity

Figure 5. Distribution of average combined Ec/Nt with different T_ADD values

Figures 6 and 7 show the scattering plot of PER vs. the average combined Ec/Nt for channel

model A mobiles with T_ADD of 9 dB and 21 dB, respectively. As shown in Figure 5, the

portion of mobiles having average Ec/Nt lower than 0 dB is much higher with T_ADD of

9dB than with that of 21 dB. We can see that packet error rate is higher in the cases of

low number of active set members. For example, in Figure 6, the mobiles having 4 active set

members has a PER of almost zero rate with the average Ec/Nt of 0 dB, while the mobiles

having only one active set member has an PER of about 30 % with the same Ec/Nt, 0 dB.

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Average Combined Ec/Nt vs. PER(307.2 kbps, T_ADD = -9dB, Channel Model A, max of 6 AS members)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

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

average combined Ec/Nt [dB]

PER

# of active set member = 1

# of active set member = 2

# of active set member = 3

# of active set member = 4

Figure 6. Average Combined Ec/Nt vs PER with T_ADD of 9 dB (Single Rx antenna)

Average Combined Ec/Nt vs. PER(307.2 kbps, T_ADD = -21dB, Channel Model A, max of 6 AS members)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

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

average combined Ec/Nt [dB]

PER

# of active set member = 2

# of active set member = 3

# of active set member = 4

# of active set member = 5

# of active set member = 6

Figure 7. Average Combined Ec/Nt vs PER with T_ADD of 21 dB (Single Rx antenna)

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Performance Results of TIA-1006:409.6 kbps(EP:2048, 3 slots), Single Rx Antenna, No RS code, Mixed DV Channel,

Maximum of 6 members in the active set, utmost {6, 18, 12, 6, 6} resolvable fingersfor channel model A, B, C, D, E

0.900.910.920.930.940.950.960.970.980.991.00

-3 -2.5 -2 -1.5 -1 -0.5 0x = log10(FER)

Pr[F

ER

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2.2.2 Performance vs. Maximum number of fingers at MS

In this section, we investigate the performance of TIA-1006 broadcast according to different

maximum number of fingers at MS even though very high number of fingers might not be

feasible. In the following simulation results in this section, we assumed that a mobile can

have a maximum of 6 members in the active set of which Ec/Io is higher than T_ADD of 21

dB. A different maximum number of fingers to be combined were simulated and compared

in terms of coverage performance.

Figure 10 shows the performance results on TIA-1006 broadcast at 307.2 kbps with single

antenna receiver and without RS coding. It is observed that the coverage increases as

maximum number of fingers increases up to a maximum of 12 fingers.

Performance Results of TIA-1006 vs. Maximum number of fingers:307.2 kbps(EP:1024, 2 slots),Single Rx antenna, No RS code, Mixed

Channel, Maximum of 6 members in the active set

0.900.910.920.930.940.950.960.970.980.991.00

-3 -2.5 -2 -1.5 -1 -0.5 0x = log10(FER)

Pr[F

ER

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Performance Results of TIA-1006 vs. Maximum number of fingers:409.6 kbps(EP:2048, 3 slots),Single Rx antenna, No RS code, Mixed

Channel, Maximum of 6 members in the active set

0.900.910.920.930.940.950.960.970.980.991.00

-3 -2.5 -2 -1.5 -1 -0.5 0x = log10(FER)

Pr[F

ER

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3 Proposed Active Set Membership and Finger Assignment Rules

We propose to define the following three parameters to define active set membership and

finger assignment rules:

1) Nas : a maximum number of members in the active set in a mobile.

2) T_ADD: long-term Ec/Io threshold.

3) Nf : a maximum number of fingers in a mobile.

Then, the following rules are proposed:

A mobile can have a maximum of Nas members in the active set of which long-term Ec/Io is higher than T_ADD. A maximum of Nf strongest paths from the sectors in the active set are assigned to fingers by the RAKE receiver. As we observed in the previous sections, the values of Nas, T_ADD, and Nf have great impact

on the simulation results for the performance of CDM based transmissions. Therefore, those

values should be chosen carefully.

4 Conclusions

In this contribution, we studied the performance of TIA-1006 broadcast with various T_ADD

values and maximum numbers of fingers. We observed that the values of Nas, T_ADD, and Nf

have great impact on the simulation results for the performance of CDM based

transmissions. We then proposed active set membership and finger assignment rules for the

CDM based transmissions 1xEV-DO evaluation methodology.

Reference:

[1] QCOM, 1xEV-DO Broadcast Multicast Service Evaluation Methodology Proposal,

3GPP2 Contribution C30-20040719-030, July 19, 2004.

[2] Samsung, C/I Equations for the 1xEV-DO BCMCS with CDM Transmission,

3GPP2 Contribution C30-20040823-071R1, Aug. 23, 2004.

[3] Qualcomm, Simulation Procedure for TIA-1006 Broadcast, 3GPP2 Contribution

C30-20040823-065, July 19, 2004.

[4] TIA-1006, cdma2000 High Rate Broadcast-Multicast Packet Data Air Interface.