N78 TDD tilt planning to get best DL throughput

Hi All.

About N78 TDD tilt planning +4.5 total downtilt looks like show the best DL throughput results.

But it is actually over horizon :slight_smile:

Any explanation?


  • height:20m
  • vertical bw:10
  • left/right angle:60/60

Which vendor?

Nokia AQQY

Calculated based on angle in rads for max distance, for max touchground point -3 dB, over horizon for sure.

Touch ground point: 254 metres.

For your info max RACH distance is 4.6 km in slot format 1:3 in Nokia with short PRACH.

Blockquote The optimal downtilt angle depends on various factors, including the antenna characteristics, site configuration, and the desired coverage area. However, if the downtilt angle exceeds the horizon, it means that a portion of the radiated energy is directed upwards, away from the intended coverage area. This can result in reduced coverage and potential signal degradation in the desired coverage area. it’s important to consider the entire coverage area and not just the touch ground point when evaluating the antenna’s performance. By the way when you say “RACH distance is 4.6 km in slot format 1:3 in Nokia with short PRACH” , I doubt RACH is used for initial access and uplink transmission, and its coverage area may differ from the downlink coverage area.

UE sees the signal at 7-8 km distance in LOS condition but RACH is to be failed , as max cell distance=4.6 km in Nokia for TDD in this slot format 1:4.
after SGNB addition ACK, UE sends CBRA , can you eleborate your RACH part a bit more ? What do you try to say?

Not sure about Nokia.

Ericsson has separate tilt for SSB beam and PDSCH beam.

I think for Nokia there is a formula to calculate the tilt using the uppereddge angle.

So check that formula may be total is that you are up tilting not down tilt.

Nokia Maa radios has 7/7.5 deg factory downtilt, so I applied -3 uptilt and total tilt became +4.5.

Yes it is Uptilt.

There is calculator on web for calculating inner and outer cell radius with arctan (inputs site height, vbw etc).

When you have 20 m tower and 10 deg vbw, 4.5 total downtil means overhorizon.

Maybe he has some buildings to cover with 5-10 floors.

Sub urban area I would say the place I trialed that 4.5 downtıilt.

Best cell throughput or best user throughput?

My curiosity is TDD radios with 6 beams has 7.32 dB beamforming gain.

Why is that gain not been considered at outer and inner cell radius?

(answer because cell radius is calculated based on rach format and UL slot format and guard period)

But beamforming gain more impacting the RSRP end user sees on field.

User Throughput.

With 4.5 degrees tilt you are not covering all users that could be covered.

Especially those close to cell.

Very good point.

I tried to find that from antenna pattern file.

Do you have more insight on how to check traffic beam tilt values?

Agree. But I checked throughput per bins higher bins also improving which most likely for user near site.

During node configuration, you will find 2 entities, useddigitaltilt (this one for SSB) and electricalantennatilt (for traffic beam).

Both are in different MOs.

Unfortunaltely in Nokia there is only 1 parameter, beamset etiltoffset.

There is no 2 diff paras for Massive MIMO antennas in Nokia.

PDSCH is beamformed so makes no sense to have a electrical tilt.

SSB is beamformed too.

It is a static beam not directed towards a particular UE as in the case of PDSCH.

Yes true. They are fix just scannimg the area every 20ms.

Good approach, but the issue is more complicated - when we downtilt or uptilt SSB, actually impact PDSCH beams :slight_smile:

Trying to find the correlation.