Cross Sector Redundancy Feature The Cross-Sector Antenna Sharing Redundancy feature introduces redundancy in configurations with dual Transmitter (TX) Remote Radio Units (RRUs) used in a multi-sector site. Cross-connections of the antenna feeders between the RRUs and the antennas prevent a single point of failure, for example a faulty RRU, from causing the entire sector to be lost. During a hardware fault the eNode-B will run in degraded mode, with one Tx/Rx branch. This makes it possible to plan and schedule a site visit in a suitable time of the particular site. CSRF By Basir Ahmed
CSRF Introduction The redundancy of the feature is achieved by cross-connecting the antenna feeders between the RRUs and the antennas. One antenna unit is served by two RRUs and one RRU serves two antennas units as shown in Figure
CSRF By Basir Ahmed
CSRF Introduction With this configuration, two sectors will be affected by one faulty RRU, losing one antenna feeder connection each as shown in figure. Losing one of these connections causes degraded performance, but there will still be coverage.
CSRF By Basir Ahmed
CSRF Implementation at test bed
(2 sectors)
Step 1: Port 1 and 4 of LTE quad port antenna sector alpha will be connected to RFIG port 1 and 4 of sector alpha respectively
CSRF By Basir Ahmed
CSRF Implementation at test bed
(2 sectors)
Step 2: Port 2 and 3 of LTE quad port antenna sector alpha will be connected to RFIG port 2 and 3 of sector beta respectively
CSRF By Basir Ahmed
CSRF Implementation at test bed
(2 sectors)
Step 3: Repeat same for the beta sector LTE antenna
CSRF By Basir Ahmed
CSRF Implementation at test bed
CSRF By Basir Ahmed
(2 sectors)
CSRF Commissioning Cell Resource 4X4 MIMO: This software doesn’t take 4 TX/RX per FRIG but just to show how to select per cell
CSRF By Basir Ahmed
CSRF Commissioning Cell Resource 2X2 MIMO: This is how we will select for 2 TX/RX per FRIG per cell
CSRF By Basir Ahmed
CSRF Commissioning 2x2 MIMO Need to set Rank Indication Reporting enable “TRUE” for LNCEL-1 & LNCEL-2
CSRF By Basir Ahmed
CSRF Commissioning 2x2 MIMO Need to set PRS TX diversity activation “TRUE” for LNCEL-1 & LNCEL-2
CSRF By Basir Ahmed
CSRF Test Scenario Before we go to test scenario, in any case if FRIG goes down it will block both the sectors and we need to re-commission the site from 2X2 MIMO to single TX as there is no auto-mode and once FRIG gets replaced, need to re-commission back to original setting. We will see the following alarms on the site.
CSRF By Basir Ahmed
CSRF Test Scenario First scenario we tested by blocking one FRIG from software and second one by taking power off one FRIG. We checked the PCI code for both the sectors, RSRP, RSRQ and throughputs and everything looks fine.
CSRF By Basir Ahmed
4x4 MIMO to 2x2 MIMO If FRIG goes down site will behave as 2x2 MIMO in place of 4x4 MIMO using 1 FRIG considering all ports are TX/RX. “Not supported right now”
CSRF By Basir Ahmed
2X2 MIMO to Single TX Cell Resource If FRIG goes down we need to commission the site as single TX but for commissioning we need to show RX diversity even though FRIG is down. Do remember if FRIG 2 is down then both cell’s TR/RX will be connected to FRIG 1 and both RX will be connecting to FRIG 2 as shown below.
CSRF By Basir Ahmed
2X2 MIMO to Single TX Although in the commissioning file we are saying that Rx diversity is coming from 2nd FRIG but as FRIG is down there will be no diversity. Both the cells will work with 1st FRIG using single TX/RX per cell.
CSRF By Basir Ahmed
2X2 MIMO to Single TX Need to set Rank Indication Reporting enable “FALSE” for LNCEL-1 & LNCEL-2 in Radio Network Configuration tab.
CSRF By Basir Ahmed
2X2 MIMO to Single TX Need to set PRS TX diversity activation “FALSE” for LNCEL1 & LNCEL-2 in Radio Network Configuration tab.
CSRF By Basir Ahmed
Single TX with Both Cell Once we send the updated parameters and site gets reset, both the cells will come back up with single FRIG. You will still see the alarm on the site as one FRIG is down.
CSRF By Basir Ahmed
Back to 2x2 MIMO using CSRF Once tower crew fix or replace the FRIG, we need to re-commission the site as 2X2 MIMO.
