7/27/2019 T200 configuration and influence.pptx

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HUAWEI TECHNOLOGIES CO., LTD.

T200 Configuration an

Prepared by : Denny Wijaya

7/27/2019 T200 configuration and influence.pptx

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Agenda

Summary

Concept

Drive Test Resu

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SummaryAdjust T200 timer has many side effect to whole network.If timer T200 is set to smaller value, the transmit end may mistakenly regard that the link is faulty and data transmission fails betransmit end receive the response from the peer end. If set to greater value, the channel are seized all along when the link is faulThus, resource are wastedT200 must be properly configured to ensure a predictable behavior at Um interface. The rules for configuring T200 include:

The potentially-existing lost frames in radio link must be detected as possible.Necessary retransmission of frames must start at the earliest possible moment.If the response is delayed due to UE failure, the T200 cannot expire before receiving and processing the next frame from thopposite end.If T200 expires and no other frames are sent by preference, the related frames must be resent in the message block.T 200 starts immediately after next PH-READY-TO-SEND.

Based from DT result, set timer T200 too big value, dropped call happened, but if we set T200 timer properly, no dropped call h

T 2 0 0 S D C C H

T 2 0 0 F A C C H F

T 2 0 0 F A C C H H

T 2 0 0 S A C C T 0

T 2 0 0 S A C C H 3

T 2 0 0 S A C C H S

T 2 0 0 S D C C H 3

T 2 0 0 S D C C H

T 2 0 0 F A C C H F

T 2 0 0 F A C C H H

T 2 0 0 S A C C T 0

T 2 0 0 S A C C H 3

T 2 0 0 S A C C H S

T 2 0 0 S D C C H 3

BMKS7 172 3706_Unhas-1 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 173 3706_Unhas-2 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 174 3706_Unhas-3 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 187 5242L2_Unhas3-7 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 188 5242L2_Unhas3-8 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 189 5242L2_Unhas3-9 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 227 3706L1_Unhas-4 200 250 250 200 200 200 200 100 80 95 180 200 180 200BMKS7 228 3706L1_Unhas-5 200 250 250 200 200 200 200 100 80 95 180 200 180 200

Before After

CELLNAMECELLIDNEName

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Concept timer T200Definition

T200 is important at Um interface in data link layer LAPDm. LAPDm has different channels, such as SDCCH, FACCH, and the transmission rate of different channel is different, so T 200 must be configured with different values.

Configuration & InfluenceT200 avoids deadlock in sending data in data link layer. The data link layer changes the physical link in which error occuto data link with no errors. At the two ends of the data link communication system, a confirm-to-resend mechanism is useNamely, receiving a message by the receiver must be confirmed by the sender.If it is unknown that the message is lost, both two ends wait for messages, so the system confronts a deadlock. Therefore,T200 is used by the sender. When T200 expires, the sender judges that the receiver fails in receiving the message, so itresends the message.When the sender needs to confirm whether the receiver has received the message, T200 starts. When the sender receives response from the receiver, T200 stops. When T200 expires, the resending mechanism starts. If the sender receives noresponse from the receiver after multiple resending, it sends ERROR INDICATION (T200 expiration) to layer 3.

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Drive Test Result (be

Setting T20found droppe

BMKS7 172 3706_Unhas-1 200BMKS7 173 3706_Unhas-2 200BMKS7 174 3706_Unhas-3 200BMKS7 187 5242L2_Unhas3-7 200 BMKS7 188 5242L2_Unhas3-8 200 BMKS7 189 5242L2_Unhas3-9 200 BMKS7 227 3706L1_Unhas-4 200 BMKS7 228 3706L1_Unhas-5 200

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Drive Test Result (af

After Sno found

BMKS7 172 3706_Unhas-1 BMKS7 173 3706_Unhas-2 BMKS7 174 3706_Unhas-3 BMKS7 187 5242L2_Unhas3-7 BMKS7 188 5242L2_Unhas3-8 BMKS7 189 5242L2_Unhas3-9 BMKS7 227 3706L1_Unhas-4 BMKS7 228 3706L1_Unhas-5

CELLNAMECELLIDNEName