Low Ul Throughput Scft,Clot 0310

8/16/2019 Low Ul Throughput Scft,Clot 0310

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2015.02.28


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Issue Summary(CLOT_UL MAC Throughput Low)Issue CLOT(TN-VLLR-0186)

• MAC T/P UL>=256Kbps had fail. Why ?

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3/23

Issue Summary

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Main issues for low MAC Throughput(>=256Kbps)• Because of TCP Window size smaller, so UE buffer size was small like “0”

— TCP Congestion Window (CWND) : In case of sender, how many data UE can send without ACK

— In TCP flow, it is always changed for congestion control• Why they happened small buffer size for UL

— Big Buffer Size from Microwave backhaul (Refer to Appendix)


4/23

Issue CLOT(N-VLLR-0186)Drop happened by Server drop/socket drop

•

During the test, Server Drop had total 119 times, so test result(>=UL 256K) was 84.09%(KPI Value : 95%)



5/23

Issue CLOT(N-VLLR-0186)Drop and Low UL Throughput MAP


Drop MAP Less than 2Mbps


6/23

Analysis(Drop Event)Drop case(UE Side)

• Even through, RF environment was good, but Buffer size was “0” because of TCP Windowsize smaller


Buffer Size is smaller

UL T/P was low


7/23

Analysis(Server Drop Event)A lof of drop cases are like this:

•

During Issue time, there were a bit of RLC Data and UE received status ACK from e-NB— It means eNB Scheduling is no issue, low buffer size happened by network(backhaul side)


Server drop by server timer

From this time, UE didn’t send the a lot of RLC Data

UE received status ACK PDU, it means that eNB was not issue


8/23

2015.02.28


9/23

Issue Summary(SCFT_UL Low Throughput)

Issue Sites

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary 9/29

Count Site Name Sector PCID Recommendation

1 I-DL-DLHI-ENB-1100 Beta/Gamma 288/289/290 Check theinterference

(Beta/Gamma Direction)

2 I-HP-HMRP-ENB-6004 Alpha/Beta 231/232/234 Check theinterference

(Alpha/Beta Direction)

3 I-KL-CRTL-ENB-6009 Beta/Gamma 276/277/278 Check theinterference (Beta Direction)

Check the test drive route for PCI 278

4 I-PB-NNGL-ENB-6002 Alpha 48/49/50Couldn’t check the site alarm due to

Site down (Communication Fail) (Note 1)

5 I-TN-EROD-ENB-6035 Alpha 204/205/206 Check the test drive route for PCI 204

Note 1 : To know low UL low T/P, site alarm should be checked whether it was normal or not.For example, if high VSWR would cause low throughput due to losses


10/23

Low UL Throughput in SCFTMain issues for low UL Throughput

• Some Cells have uplink interference that are RSSIvalues higher than -90dBm andInterference values higher than thermal noise (-101dBm)

— eNB “1100” Beta Sector : Interference power level : -90dBm, RSSI level : -84dBm

— Refer to Appendix (RSSI/Interference level from LSM)• Belows are UL interference evidence from log data

— The BLERshould be smaller or equal than 10%. If the value is larger, then, there is an indication of

bad RF environment‐ eNB “1100” Beta Sector BLER is about average 53%.

‐ Typical causes of bad BLER are uplink interference, bad coverage (holes in the network, etc.)

‐ But, from LSM check, high BLER happened by interference.‐ To know exactly, That sites should be checked by RRH dump

— Power Headroom‐ low value of power headroom means that UEs do not have available power to transmit in

the uplink and hence, UL throughput is low.• eNB “1100” Beta Sector almost had 0dB

‐ Typical causes of low power headroom are uplink interference



11/23

Why ? UL Throughput is low•

Because of uplink interference, the BLERhad more than 10% in beta/Gamma cell• Also, Power Headroom is low

— low value of power headroom means that UEs do not have available power to transmit in theuplink and hence, the throughput is low.

— Typical causes of low power headroom are uplink interference

Issue Site_I-DL-DLHI-ENB-1100

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11 /28

Bad BLER

Power Headroom Low


12/23

Issue Site_I-HP-HMRP-ENB-6004

Interference Issue(Alpha/Beta)


Bad BLER


13/23

Issue Site_I-KL-CRTL-ENB-6009

PCI 278(Gamma) RSRP was too low because drive route was not enough to get ULthroughput

• RSRP CDF between PCI 276 and PCI 278— In case of PCI 276, it was not issued

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14/23

Appendix. RSSI and Interference Level


IoT level is highthan thermal noise

RSSI level is highthan thermal noise

I-DL-DLHI-ENB-1100-PCI 288


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I-DL-DLHI-ENB-1100-PCI 289


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I-HP-HMRP-ENB-6004-PCI 231


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I-KL-CRTL-ENB-6009-PCI 277


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Appendix. Drive Route for I-KL-CRTL-ENB-6009

For PCI 278(Gamma), Drive Rout is not enough to get UL throughput

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

18 /28

eNB_ 6009(Gamma)

1km point fromeNB 6009


19/23

Appendix. Drive Route for I-TN-EROD-ENB-6035

About PCI 204(Alpha), Drive Rout was excessive, So week signal area was too much.

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20/23

Appendix_RRH Dump(Delhi)


There are detected something


21/23

Appendix_RRH Dump(HP)

There are detected something



22/23

Appendix_RRH Dump(Kerala)



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Copyright and ConfidentialityCopyright © 2012 © SAMSUNG Electronics Co., Ltd. SAMSUNG Electronics reserves the right to make changes to the specificationsof the products detailed in this document at any time without notice and obligation to notify any person of such changes.Information in this document is proprietary to SAMSUNG Electronics Co., Ltd. No information contained here may be copied,translated, transcribed or duplicated by any form without the prior written consent of SAMSUNG Electronics.

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Low Ul Throughput Scft,Clot 0310