Showing posts with label Work. Show all posts
Showing posts with label Work. Show all posts

Monday, January 19, 2009

Data speed is cannot reach to upper limit

Today after checked the network for voices and data communication, i find new problem in the network, theoritically CDMA network can give 2 user with 153.6 kbps [5X system, using 16 code of walshcode] 2 users with 76,8 kbps [4X system, using 8 walshcode codeing] and 2 user with 38.4 kbps [3X system, using 4 Walshcode coding] or 4 users with 19.2 kbps [2x system using 2 walshcode code]data speed.
User can reach 153,6 kbps if user is very closed to BTS and get better Ec/Io, and low user active in that BTS sector, after tested and investigate our network with data call i just get 38.4 Kbps, its mean the reservation Supplemental Channel just give 3X system, its will be a problem for data network, after checked statistic data at that hour, i find just 2 active voice call and 1 active data call in the network.
ouch some new problem and i need some time to analyze this problem...
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Thursday, July 19, 2007

CDMA Drive Test Analysis

on monday, july 16, 2007, i go to semarang at 06.00 in the morning, we arrive in semarang at 07.00 in Ahmad Yani airport, me and mas oka handiman usually we said oka, will do ULO with dirjen Postel in solo and jogja, before we go to jogja and solo we stay 1 night in semarang, go to office and take a result of drive test for solo and jogja, this is the analyze...



a lot of HO [handover] failure
hand over fail in actual condition, cause failed when 4 handHandoff to softerr HO [3 hand], this failed cause the equipment cannot handled the MS [mobile station] to handoff 3 hand or usually we said softer hand over, to optimize this error we must invited the expert in telecommunication equipment to solve this problem , the other reason when HO failed cause lack of coverage in the area, that make MS cannot move to other PN cause there are no dominant PN or donor. to optimize this problem that we must put additional site to cover the area


feeder swap
feeder swap is installation fail, cause to achieve the OnAir target or etc, usually feeder swap in sector 1 to sector 2 or sector 0 to sector 3, as plan sector must 1 handled the call but in actual sector 2 handled the MS. this is feeder swap factor. solution foer feeder swap is we must swap back again the feeder to the normal position, do not need expert engineer, just need field engineer to swap the feeder.

cannot call
there are a lot of reason for this fail, lack of FER [Frame Erasure Rate], Ec/Io to high, or a lot of pilot polution, this three reason is main reason if MS cannot do a call, HO failure from 4 hand to 3 hand or softer HO cannot make drop call or call pre release. cause the MS still handled by another hand to do a call..

Site overshooting
Site oversoot is cause 1 sector shoot to another sector in high power, this overshoot make there are no dominant PN in MS, cause there are a lot of PN with high power in MS.
the solution for this oovershoot sector is tilting the sector, reduce power in the sector is the ast solution, for this failed.