HISILICON SEMICONDUCTORHUAWEI TECHNOLOGIES CO., LTD. Page 1

Jabo 2G Network Equipment Related Voice Quality(Silent Call) Issue Audit

Date Count of Silent Call

2013.08.23 1541

2013.08.24 0

After:Before :

Some complaints on silent call(mute)/one way audio received. Suspect Hardware/Transmission issue causing some voice quality issue(incl. silent/one way call)

Collected site CDIG log file to identify cells with mute call issue related to equipment(hardware/transmission) in all sites under 17 BSCs in Jabo network. Conducted call testing on site, analyzed BTS /board log and did loopback operation to locate the root cause of mute call. And verified the relation between transmission alarm and mute call issue.

Finding 1: Around 1500 times mute call per day recorded in VIP cell BOSTONMD2(site id:24,cellid:180) under BSC Gambir. Confirmed the mute call caused by RF module MRFU faulty. Mute call issue was solved after MRFU board was replaced on 00:00, 24 th, Aug 2013.

Problem Background

Action Taken

Result: Silent call related to equipment issue found in some cells under BSC Gambir and BSC TBS Metro1.

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Finding 2: Some cells under BSC TBS Metro1 with silent calls recorded and caused by Abis transmission issue. The silent call disappeared accordingly after transmission alarms cleared. e.g. in site BUKITDURIBRTM(site id:28) under BSC TBS Metro1, around 130 silent calls from 09:00-10:00 AM, 19th, August 2013 were recorded and many transmission alarms occurred synchronously. Silent call recording disappeared after alarms cleared starting from 20th, August 2013.

9:00-10:00 AM, 19th, Aug130 mute calls in site id: 28

Jabo 2G Network Equipment Related Voice Quality(Silent Call) Issue Audit Cont’

00:00-23:59, 21th, AugNo mute call recorded in site id: 28