- This topic has 65 replies, 1 voice, and was last updated 3 years, 10 months ago by
.
-
Posts
-
Promod,
sorry… i’m more interested in helping on practical issues than explaining the definitions of some parameters… i’m just too lazy. furthermore, it is my work, so i should get paid for doing so 😉
thanks for understanding,
regards,
pixDear sir,
Is it necessary NECI value is enabled dual-rate in network to support all class mobile? Pls suggest me..
Regards,
PromodI HAVE LOW TCH AVAILABITY IN SOME OF THE CELLS AND IN THAT SOME CELLS ARE HAVING DCR IS VERY GOOD AND SOME CELLS ARE HAVING WORST DCR. IS THAT TCH AVAILABILITY IS GOING TO AFFECT THE DCR AND HSR IN THE NETWORK?
EX:TCH AVAILABITY IS 27%
CASE1:DCR IS 1.3 AND HSR IS 98.23
CASE2:DCR IS 7.8 AND HSR IS 70.45PLS SUGEEST ME
promod,
i don’t know what is NECI…
regarding the tch availability, i answered in another of your thread.Dear Pix,
1.can i know the reason why it is getting reduced? Is it due to hardware issue or due to some other reason?
2.Why it will affect the HSR due to low TCH availability even though there is no congestion and no hardware alarm?
1. usually, the availability is only related to the physical availability of the hardware. If a TRX is down or locked, then it is unavailable.
2. if low tch availability leads to tch congestion, then you will measure a low HSR
if low availability doesnt lead to tch congestion, then you have no problem 😉Dear pix,
Can u tell me how we will calculate the TCH assignment depending on the TCH availability and TRAFFIC?
hello promod,
you can’t calculate the number of TCH assignments according to the traffic(erlang) and the TCH availability only…
You also need to know the call mean duration… and you can’t take into account the TCH availability, it doesn’t enter in the formula 🙂
tch assignments = TCH traffic(erlang) / call duration.
Dear Pix,
If i use the adjcent freq in the different site which are looking face to face cell with different BSIC what will be the result? As far as i observed HANDOVER is becoming delay due to Adjcent freq? but it won’t make handover failure because in GSM we should maintain 200kz difference in each freq.Am i correct Pix. and it also apply in the with the same BCCH and different BSIC.
Pix can u tell ur comments on this issue.
promod,
1. adjacent channels neighbours : it will cause a voice degradation during HO, and if it happens that the
neighbour cell > (serving cell + 9dB)then you will face voice quality issues during the talking as well, not only the HO.
C/Iadj > -6dB (3GPP recommendations) (or is it -9dB ?)
2.
Same frequency :
C/I > 12dBSo you need to have the serving cell with a signal higher by 12 dB than the neighbor cell using the same frequency. That can be difficult to obtain !!
And it is not possible to declare an adjacency between cells using same BCCH frequency (even if different BSIC). It is forbidden.
Dear Pix,
Can u tell me how GHOST RACH will affect the SDCCH? can you explain it.
promod,
To be simple, you can consider ghost rach as “useless” signals which are decoded by the BTS as “useful” signals.
So when receiving those “dummy” signals, the BTS will consider it is a “RACH” access and will start allocating a SDCCH for it.
Step 2: the bts has allocated the SDCCH and sends a response to the MS: “Go to this channel”. But since there are no MS (the original RACH signal was not generated by a MS in the 1st place !), there is no answer in uplink. The SDCCH is anyway “reserved” and will be deallocated after the expiry of a certain timer.
So the ghost rach can lead to sdcch congestion, if it is in very large amount.
Hi All,
we are experiencing very low handover success rate 7.8% or 5% within a site for a whole 24 hr period.
the site is a stand alone, therefore no other neighbors are defined except its cells.the BCCH frequencies are has the required 200KHz seperation.
today, we decided to delete and recreate it again, the results shows no improvement.Statistics shows that cell 2 is trying to handover to cell 2 but may be out 0f 29 attempts,only 1 or 2 will be successful.
the site configuration is 2+2+2, and we are using synthesizer FH.
can some one help me resolve this issue please??
Emmanuel,
what do you mean “cell 2 is trying to handover to cell 2” ? i think you made a typo error ?
could you please write down the HO requests, the HO attempts and the HO success for each couple of cells ?
Now, at a first glance:
– BCCH separation : 200 kHz between 2 neighbors is too small. You need at least 2 channels separation (= 400 kHz) for instance : bcch(1) = 12 and bcch(n) = 14.– 29 requests.. it is very small. This value is too low to make correct statistics. It can be due to just one or two mobiles trying to perform “emergency ho” in very bad conditions…
hope it helps..
regards,
pixHi Pix,
I wanna know y Rach sucess decreases if the RxLevMin is increased above -100(i.e -98,-96 in nineties etc)
Thanks in advance
Tufail
- The forum ‘Telecom Design’ is closed to new topics and replies.
