congestion in RRC phase (RRC capacity)

[Mr_Piongly]

Hi all

in GSM system we have the SD channels that transport signalling traffic.
If we have blocks we can take a TS (time slot) dedicated for TCH and define it as new SD.
In this way we can improve accessibility

In UMTS we have RRC connection , but i don't understand when we will have blocks.
If we have only a carrier f1, how many simultaneous attempts are neccessary to have blocks ? how is it possible whe we need to expande the rrc connection capacity ?

thanks

[Walid Madih]

Hi all

in GSM system we have the SD channels that transport signalling traffic.
If we have blocks we can take a TS (time slot) dedicated for TCH and define it as new SD.
In this way we can improve accessibility

In UMTS we have RRC connection , but i don't understand when we will have blocks.
If we have only a carrier f1, how many simultaneous attempts are neccessary to have blocks ? how is it possible whe we need to expande the rrc connection capacity ?

thanks

in RRC it's not count by number the below cause can cause rejection:
- CAC because of UL/DL power
- NO CE availble
- No Iub resource.
- No Code available.

[zeezzoo]

Dear,

the Capacity in UMTS is related to : Codes , CEs , Downlink Power , RTWP (which is uplink interference = Load of the cell) and Iub Resources .

you can have blocked RRC (Rejected) when you don't have enough resources of at least one of the above mentioned .

first UE sends RRC Connection Request . then if the system has enough resources , it will send RRC Connection Setup (RRC Accepted) .

[riyantoyadi]

for RRC 4 parameter : Code, Power, CE and Iub that's all

[Mctest]

for RRC 4 parameter : Code, Power, CE and Iub that's all

Does the uplink interference influence on the RRC Connection capacity?

[Walid Madih]

Does the uplink interference influence on the RRC Connection capacity?
yes if ul cac is enable for ul power

[manson]

in RRC it's not count by number the below cause can cause rejection:
- CAC because of UL/DL power
- NO CE availble
- No Iub resource.
- No Code available.

How do we know, RRC blocking due to UL/DL power...?
And 4 of cause...
Anybody can explain it...?
Sorry, newbie.. :rolleyes:

[riyantoyadi]

Huawei have special counter about that :

VS.RRC.Rej.Power.Cong Failure of requesting for power resources.
VS.RRC.Rej.UL.CE.Cong Failure of requesting for uplink CE resources in a cell.
VS.RRC.Rej.DL.CE.Cong Failure of requesting for downlink CE resources in a cell.
VS.RRC.Rej.Code.Cong Failure of requesting for code resources.
VS.RRC.Rej.ULIUBBandCong RNC admission algorithm rejection due to congestion of the uplink Iub interface bandwidth.
VS.RRC.Rej.DLIUBBandCong RNC admission algorithm rejection due to congestion of the downlink Iub interface bandwidth.

hope it usefull

[Ummi]

very usefull info

[Irna]

How about RAB? is there any differences?

[Mctest]

How about RAB? is there any differences?

Of course yes!Because you may have resources for the establishment of the RRC connection and no resources for the RAB establishment(for example no available codes for the requested service)

[zeezzoo]

How do we know, RRC blocking due to UL/DL power...?
And 4 of cause...
Anybody can explain it...?
Sorry, newbie.. :rolleyes:

power cong is always in the downlink .
because one cell has a max power (20 watt , 40 , 60) according to nodeB hardware & license .

when the cell had already used all the power it has , it cannot connect to a new user since there is no enough power to dedicate it to this new user .

for uplink power : each UE has it's own power which is enough to overcome the path loss in all the cells . but when the cell is loaded the noise floor increases (50% load ==> rtwp = -103 dBm theoretically ; RTWP = Uplink Interference) ==> the UE has to use higher power to achieve the required BLER for a given QOS service (there is different BLER requirement for each service ; BLER = Block Error Rate) .

let's say that for a given service and a given cell load the UE cannot achieve the required BLER even when using the max power ==> the connection cannot be established . but if the UE moved closer toward the site ==> it maybe get the service because in this case the path loss became smaller and we have extra power to achieve the required BLER .

This is what is called cell breath = cell shrink which is only on the uplink (not on the downlink) because all the UEs under this cell can decode the PCPICH (33dBm default) but some of them are out of the uplink coverage , so to speak , because no enough power to achieve the required BLER .

so finally when we have DL power problem ==> it can be counted . but when we have UL power problem ==> it cannot be counted because the UE cannot connect to the network (no message can be sent and received correctly from the UE to NodeB) .

sorry for writing too much . hope it will be usefull
BR,

[redtomato168]

Huawei have special counter about that :

VS.RRC.Rej.Power.Cong Failure of requesting for power resources.
VS.RRC.Rej.UL.CE.Cong Failure of requesting for uplink CE resources in a cell.
VS.RRC.Rej.DL.CE.Cong Failure of requesting for downlink CE resources in a cell.
VS.RRC.Rej.Code.Cong Failure of requesting for code resources.
VS.RRC.Rej.ULIUBBandCong RNC admission algorithm rejection due to congestion of the uplink Iub interface bandwidth.
VS.RRC.Rej.DLIUBBandCong RNC admission algorithm rejection due to congestion of the downlink Iub interface bandwidth.

hope it usefull

but how solve RRC reject

[agenov]

but how solve RRC reject


Increase congested resource or/and apply different load algorithms (vendor specific).

BR
Alex

[Irna]

what kind of rejection and specific caused already explain

[adewijaya]

1. Congest due to CE --> add more CE
2. Congest due to Code ---> add more Code or Carrier
3. Congest due to Power ---> decrease PCPICH Power or add more carrier

[redtomato168]

1. Congest due to CE --> add more CE
2. Congest due to Code ---> add more Code or Carrier
3. Congest due to Power ---> decrease PCPICH Power or add more carrier


My network, some cell have UL load very high always over 80%, 90% or 100%. At this time RTWP is also very high (-65 : -90 dBm). But i dont how to improve RTWP or decrease UL Load?

[Ummi]

hope this issue already solved, isn't it?

[zeezzoo]

My network, some cell have UL load very high always over 80%, 90% or 100%. At this time RTWP is also very high (-65 : -90 dBm). But i dont how to improve RTWP or decrease UL Load?

dear your RTWP is very high and i think -90 ==> -65 dBm are not caused by the traffic generated in the network . it's interference , maybe external .
you should plot the traffic & RTWP on charts (on hourly basis) to make sure that you have a high RTWP even when you have very low traffic ==> this means you have interference .

the first preventive action is to change your noise floor where you have a parameter (used by the admission control) by which you set the value of the noise floor . huawie have this parameter but i doun't know if other vendors have it. after changing that parameter you will find that you have lower # of rejected RRCs .
but finally you should determine the source of the interference & conduct the problem to the related authorities .

[adewijaya]

actually even this change depend on interference suffered, find the resource will be more advantages. Using LMT to know what kind of uplink interference is a simple ways

[agenov]

My network, some cell have UL load very high always over 80%, 90% or 100%. At this time RTWP is also very high (-65 : -90 dBm). But i dont how to improve RTWP or decrease UL Load?


Who is your vendor?

BR

[gogotchiya83]

What about the RRC_ reject_Timeout ?
What does it means? what it is the reason?

[tthach830]

in RRC it's not count by number the below cause can cause rejection:
- CAC because of UL/DL power
- NO CE availble
- No Iub resource.
- No Code available.

When there is no code available which code are we talking about?
Scrambling code / Channelization code? I understand the code is to be assigned to the UE. So is this the channelization code or scrambling code?

[Irna]

OVSF code,its mean channelization code

[johny]

hi, can you explain the handling methods for resolving the above mentioned types of congestions ... or perhaps refer a doc that explains resolutions to the above ....thanks,John

[YANG SONG]

1. Congest due to CE --> add more CE
2. Congest due to Code ---> add more Code or Carrier
3. Congest due to Power ---> decrease PCPICH Power or add more carrier

if you have no resources to add more CE\ Code or power.you can also shut down the UL PS 384, 256 to reduce Resource consumption.

[johny]

Thanks Yang - For code congestion I cannot decrease codes in some other cell or the codes are shard in a pool ?

[YANG SONG]

Thanks Yang - For code congestion I cannot decrease codes in some other cell or the codes are shard in a pool ?the code and power belong to a cell, add 2th carrier is a good way. you can't share the code and power in some other cell , unlike the CE .in our network, there is a feature to share code and power between R99 and HSPA, First of all you should be sure what kind of serves types congestion, tihis is the best way.sorry my Englis is not good.hope your good news!

[atifbukhari]

the code and power belong to a cell, add 2th carrier is a good way. you can't share the code and power in some other cell , unlike the CE .in our network, there is a feature to share code and power between R99 and HSPA, First of all you should be sure what kind of serves types congestion, tihis is the best way.sorry my Englis is not good.hope your good news!
Hi, I would like to know about the feature which shares power between R99 & HSPA.