..::its about journey::..

..::difficulty in CDMA::..

2009-01-28T13:44:00.007+07:00

Yah first word after a lot of problem in our network..major issued in [W]CDMA network is: limited capacity by power, Walsh code, Traffic Channel Element, Overshooting sector that will make quality decreasing and etc
may be i will break down case by case and give a recommend what we can do to solve [in my experiences]

Capacity limited by Power

In [W]CDMA system power is main issued of capacity, a lot of user access the network will make Ec/Io increasing, like show in a picture

too many user access the sources will make power closed to threshold. what we can make to increase capacity that caused by power limited. first of all we can increase transmit power [carrier power/cell power] that will make another space to user for access the traffic channel, increasing transmit power must balanced with limited the coverage too, cause it higher transmit power will make another neighbor cell will polluted, or we can decrease DGU [Data Gain Unit] or usually we said pilot, sync and paging, to make more spare for user. usually this case happen in urban city, cause a lot of user access Data and Voices in one time. another case is capacity limited by TCHe and Walsh Code, below is my recommend for increasing capacity will put in another point

Capacity Limited by Walsh Code

below is a simple picture of Walsh Code Tree
in [W]CDMA system Walsh code tree 0 [W0] is used by Pilot to send user a parameter that used in [W]CDMA system like NL [Neigbor List], and etc, Walsh Code tree 1 [W1] is used for paging slot, LAC, P_REV, MIN_P_REV, T_ADD, T_DROP, T_COMP, T_TDROP is send from this slot, and Walsh Code 31 [W31] is used for sync slot.
Walsh code tree in CDMA usually use Walsh Code 64 [Vendor and Customer Agreement and specification] increase Walshcode tree will increasing Traffic Channel Element [TCHe] too, cause there are will increase and make spare for user used the sources of CDMA network.

so now we have increase more transmit power [carrier/cell power] and if still have a problem with limited capacity, we check a walsh code occupancy, if walsh code limited too, so we increase the length of walsh code. if still have a problem with a capacity again, please check how much percentage of Soft Handoff [SHO] in that site, if SHA larger than 40%, we must decrease SHO, how to decrease SHO in our network? i will write again tomorrow in another topic.

Is there a static handoff at CDMA network

2009-01-21T14:11:00.002+07:00

once again i get a statement there is in (w)cdma network have a static handoff like i quote from my email below
Decrease T_ADD and T_Drop can adjustable if Our System Right Now Using Static Handoff (you can see parameter below)...
and
That Parameter above is Dynamic Handoff, so what ever we adjustable T_Add and T_drop for minimize SHO rate, this is no impact because system will automatically measurement EcIo from MS Side, it means the never consider value set for T_Add and T_drop
my first question is, is there static handoff in (W)CDMA network??can i get the literature?and after get that email i use www.google.com to find is there static handoff in (w)cdma network? and i cannot get the theory or any literature? or "he" can give a clearly explanation for his statement??
i think a dynamic hand off is a methode for mobile sense for handoff, in a dynamic hand off there are have a threshold function, there are different definition for dynamic handoff threshold

in UMTS, quality function is defined as the best pilot strength
in CDMA 2000, quality function is defined as agregate pilot strength

quality function is controled by t_add, t_drop, and t_comp function to measure the mobile sense for network quality, so t_add, t_drop and t_comp is used for quality control for dynamic (w)cdma handoff.

how can 'they' make a wrong calculation for call drop rate

2009-01-21T13:22:00.002+07:00

Oh man...!!! its truly foolish man that always make a wrong calculation, isn't he/she don't learning math or calculus when they get in school or university??the simple question for 'them', there are a lot of data percentage, can average that percentage to get new percentage statistic..?oh its really bad idea..
in my opinion, its cannot be a new percentage is we average a lot of data percentage, cause there are too many dividend if we calculate one by one, let we take one simple case, if we have a normal release about 1000 a day and have a radio drop about 5, it say we have 0.5% radio drop, and we have 2000 normal release and 5 radio drop in second day, that we can say we have 0.25% radio drop in second day, if we just calculate directly with just average the percentage how many percentage we get?
average(0.5%+0.25%), its equal 0.375% -> is it valid or not? i think not, the second way is we summary our normal release and radio drop first and take the average for this all summary let we calculate...
so we have 3000 normal release and have 10 radio drop, so average for this two day is 0.33%
so what kind of calculation that can near the true statistic..?
yah its can be a proof concept for 'they' that call himself a master...

Data speed is cannot reach to upper limit

2009-01-19T16:49:00.002+07:00

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...
...
..
.

CSSR Decrease in our network

2009-01-19T16:35:00.004+07:00

In december 2008 CSSR [call setup success ratio] in our network is going to decrease to 85% [threshold 95%] its mean that a lot of call being rejected. after get some reason why a lot of call rejected and collect all support data that we get conclussion how to solve this problem.
its a simple way to analyze the problem
if there are normal in Traffic Channel Element than please check in Walsh Code Occupancy [CDMA and WCDMA]..if occupanciest of walscode is upto 98% its mean we need to upgrade from lower WC to greater WC, the impact is a lot user can access the network and make the resources is used up. in CDMA and WCDMA system, user to access the network is limited by power, WalshCode, and Traffic Channel element.
After already checked all supported document and bts reason etc, the main problem in the network is forward power is limited, and after we checked in SHO statistic its show a lot of user is mobile in that BTSes, we cannot limited and user to access the resources, cause if the user get dominant Ec/Io and can be a main pilot, user will used that resources., so the way that we can do is give more forward power that can boost the user and give a space for user to used the resources, and decrease overhead message to give a lot space for traffic power.

CDMA Drive Test Analysis

2007-07-19T08:27:00.000+07:00

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.

single site check

2007-07-07T08:33:00.000+07:00

wah its first time that i must go to the office in saturday, yah its ok, cause its just before commercial launch for smart.
tomorrow do a ssc [single site check] with anritsu tools for site master. but there are no one analyse the result...till today, i just wait for the analyse VSWR analyse and DTF analyse to make decision is the BTS is good instalation or not...and than check for PN and receive power in handset. at monday we will do DT [Drive Test] for quaity signal for that BTS

Done 467 Planning site

2007-05-24T18:03:00.001+07:00

Wawh... feel a lot of tired at last 3 days...do a plan for all sumatera area, for additional site for Hutchison CP Telecom that will released in Ph2+ for sumatera area, all of 467 site in road and small city in sumatera...

Yah its make me bored, but my wallpaper give me a spirit for finished the job...for 2000 sites, it is to small, but i thinks for all sumatera there are have 1164 sites, that will be issued in Ph2+ Release 1...waw i create a new network in sumatera.

Plan is same like art, we put the nominal, arrange antenna height, optimization and execute to sitac to find candidate.. its more fun to me...