BaiTip of the Day - May 9th, 2018 - Recommended eNodeB Advanced Settings to Optimize Channel Conditions

This BaiTip was written by Nitisha Potti.

These Advanced Settings will optimize the KPIs, but won’t drastically improve the RSRPs. Although these settings will help the UEs latch on to the eNB by improving the RF signals in bad RF conditions, a minimum RSRP of -110 dBm is recommended. Going below -110 in the summer or -100 in the winter is not advisable.

LTE>>>Advanced>>>Power Control Parameters

1. Max Pathloss: Default is 125 at present, leave it as it is and only change to 135 for high NLOS situations for eg. in cases of dense foliage in between UE and eNB.

2. Target ul SINR: Default is 5 and recommended.

3. Po_ue_pusch: Default setting 0, recommended setting 7, this will increase the uplink UE signaling power.

LTE>>> Mobility Parameters>>

1. A2 Event Threshold: Default setting 65, recommended setting 0, this will accommodate a min RSRP of -140 dBm and stop A2 triggers due to which CPE drops occur as CPE is flapping between two eNBs.

2. Cell Selection Parameter >>> Qrxlevmin (dBm): Default is -60, recommended change to -70. Min RSRP required for cell selection= 2Qrxlevmin+Qrxlevminoffset. Thus, setting the parameter = -70 will give min RSRP=2*70+1 = -139dBm.

LTE>>>Advanced>>>Random Access Parameters

1. Zero Correlation Zone Config: Default is 10, if the distance needed to be covered by eNB is greater than 5 miles, we recommend changing this to 12, which will adjust the maximum distance covered to around 9 miles. The ZCZC can be increased to 15 to go beyond 9 miles, if there is clear LOS.

Hi Rick,

I actually tried using the recommended settings from Nitisha’s original post and found that on latest Halo B eNB firmware you can’t:

1- You can’t change the Po_ue_pusch setting to 7, the eNB does not accept this value

2- Mobility Parameter Settings are no longer exposed in GUI

I could be wrong, I am on the road and can’t test right now but I recall running into those 2 problems last week with a new eNB running latest Halo B firmwares

Cheers
Pierre

This will be fixed in the next HaloB release.

Hi Rick,
This parameter works great with distance and NLOS, but we notice that upload is never better than a few Mbps even if download get top to 90 Mbps. Subframe are set to 3:1 DL:UL so I guest we should at least be able to get something around 15 Mbps Upload ?! Why isn’t it working ?

In LTE, the 3:1 Ratio applies to available Resource Blocks for DL and UL. It does not apply to bandwidth directly. Bandwidth is affected by the Modulation Coding Scheme (MCS), which is derived form SINR and RSRP. The better the MCS the higher the QAM rate, hence the better the throughput. Below is a chart for a Revision 9 eNB, set at a Subframe Assignment (SF) 2, Special Subframe Assignment (SSF) 7, which gives you a 3:1 ratio of Resource Blocks. This chart if for a 20 MHz channel.

The following chart is for a 2:2 ratio of Resource Blocks on a 20 MHz Channel. It would be a SF-1 and a SSF-7.

You can see how MCS/SINR/RSRP levels affect throughput.

Is there any change in Receiver Sensitivity with 10 or 15Mhz channel size?

Hi Rick,
Currently with a mikrotik LHG LTE UE connected to ENB,
SNR display in ENB: 15 dB
UL MCS: 22

Maximum throughput from UE to ENB gateway :
7.5 Mbps TCP with 4 connections speed test

Maximum throughput from ENB gateway to UE :
90 Mbps TCP with 4 connections speed test

If I check the table you send, I could expect at least 10 Mbps throughput… but I had never see.