4G capacity and KPIs estimation for mass events

RAN
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Hi Experts!

Let’s imagine we have a VIP area were it is supposed to be mass event (kind of exhibitions).
In that area we have indoor and outdoor cells. 2-3-4G networks.
There is only info that about 2000 people will come to that event.
No Volte. only CS voice.
Let’s assume that all users support 4G.
I need to estimate capacity for 4G network in BH.
There are 46 4G cells (25 cell with 10MHz and 21 cells with 15MHz).

Of course it is obvious that not all 2000 people will use 4G network simultaneously.

Do you have any similar experience and considerations about such tasks?
Is it possible to tell number of 4G users in Busy Hour: 5% or maybe 15% is it enough?
Any ideas would be grate to hear!

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Are you considering all these 2000 people are from a same service provider?

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Let’s suppose so. Yes.

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In mass events as mentioned scenario mostly traffic is for Upload, which requires high PUCCH capacity.

Solution like massive MIMO can help here or team can plan to increase PUCCH bandwidth for CQI to cater more RRC users and increase max num RRC license to max.

Feature like idle mode load balancing and inter Freq load balancing can help further.

Parallel uplink throughput improvement feature like UL Comp can help.

Users having MO Call can move to lower rat direct by SBHO feature so PRB utilisation can be optimum.

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Remove Carrier Aggregation DL & UL.

Increase RACH Capacity.

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For RACH Capacity you mean to increase PRACH cyclic shift? I.e. cell range to pick traffic?

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3GPP: prach-ConfigurationIndex

In order to increase PRACH density.

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It indicates RACH timing only i.e. subframe where RACH to transmit.

Number of RA preamble part of SIB2 can help.

But as per scenario it’s for mass event planning so need more brainstorming over capacity increase features and solutions…

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Yep, it also indicates the amount of PRACH.

PRACH Configuration Index
PRACH Configuration Index590×647 92.9 KB

Regular value is 3, which means SFN = 1, you can change to 6 in order to have 2 Subframes with PRACH.

Increasing PRACH density.

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Anyone aware of such mass event handling feature for 5G SA as well?

For 3G time there are many such features per vendor seen.

But from 4G features wise solution less.

And now for 5G good to know if any such features exist.

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For such event, first thing to be determined from operator’s side is the QoS they tend to achieve.

Some carriers are relying on certain values for user DL & UL throughput.
E.g., 3 Mbps and 1 Mbps for both DL & UL, respectively.

With key assumptions can be as follows:

  • MLB is on
  • Guaranteed active users → total should be respected on total audiences/attendants of the crowd
  • Operators’ business insight on user behaviors during busy hours can be calculated
  • Network capability, it will depends on what Mimo scenarios to be used, MCS, as well as modulations
  • …

With total bandwidth available 565 Mhz (25 cells on 10Mhz + 21 cells on 15Mhz)

With 2000 crowd,

My personal judgement: should be enough.

(I’ve done over 20,000 crowd with total 400+ MHz bandwidth with “legacy” 2x2 MIMO)

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Uplink user throughput very hard to achieve in Mbps even I seen max 500 kbps only.

What value you’ve seen in your network?

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Every operator has their own way to determine QoS, hence it yields on empiric values for number of guaranteed user per cell.

In my case,

  • FDD 20Mhz : 185
  • TDD 20Mhz : 185
  • FDD 15Mhz : 160
    And so on.

The “guaranteed user” number is subjective to each operator strategic point of view, most of my case: user throughput + latency based on historical OSS measurements.

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Numbers are subjective only, not guaranteed in real scenario.

May be user throughput calculation method different with your operator.

@RFSpecialist, any idea over this for NR SA?

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Indeed.

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If there are already 46 cells there should be no issue. At events, uplink capacity is challenged. And usually, during break time, number of active users can be anything between 30% to 50% from those 2000 users.

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Why should we remove CA DL/UL?

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This is because user traffic is voice only (network throughput capacity requirement is only i.e.,8kbps, no need CA, but need carefully schedule multiuser in each frame to handle average 50 users per cell). Total capacity requirement is not high, for example 2000*8kbps=16Mbps for the UL, considering network overhead, radio overhead and efficiency 50% and 50%, the PHY rate is about 64Mbps for UL. as @stev.aryanto mentioned, it can be easily handled with the total 565MHz, which is time-shared by both DL and UL (so we provide budget of 128Mbps for UL). We need schedule around 6 users per slot and accommodate around 50 users each 8 slots to fully utilize 8 the HARQ processes. In each slot, 6 users user OFDMA sharing 10MHz or 15MHz bandwidth, each one only have around 1-2MHz bandwidth. If MCS rate is >1 bps/Hz, each one can get 1-2Mbps throughput. That’s enough.

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