Replace the default loopback MME address (127.0.0.1
) with the IP address of ORS 1.
mme_list: [
{
/* address of MME for S1AP connection. Must be modified if the MME runs on a different host. */
mme_addr: "192.168.99.1",
},
],
Replace the default loopback GTP address for eNB1 with the IP address of ORS 1. However, the IP address of ORS 1 is already being used by MME running on the same ORS, and thus cannot be used. To work around this, create an IP alias as the GTP address of eNB1 by running the following commands :
ifconfig // get network interface name. e.g.enp2s0
ifconfig enp2s0:1 192.168.99.3/24 // create a different name (alias) for the ORS 1 IP address
ifconfig // check alias has been created
Then the GTP address in enb.cfg
can be replaced with the new alias value.
/* GTP bind address (=address of the ethernet interface connected to the MME). Must be modified if the MME runs on a different host. */
gtp_addr: "192.168.99.3",
The two eNodeBs are communicating through X2 interface. Thus the X2 peer address is the IP address of the neighbour eNB, which is ORS 2.
/* X2 address : IP address of the other eNB */
x2_peers:["192.168.99.2"],
Each eNB must have a unique ID so that MME can differentiate them. Here you can leave the default value, which is :
/* high 20 bits of SIB1.cellIdentifier */
enb_id: 0x1A2D0,
eNB2 must be described in the eNB1's neighbour cell list.
/* list of cells */
cell_list: [
{
plmn_list: ["00101",],
dl_earfcn: 38350, /* 1890 MHz (band 39) */
n_id_cell: 1,
cell_id: 0x01,
tac: 0x0001,
root_sequence_index: 204, /* PRACH root sequence index */
/* Neighbour cell list (used for handover) */
ncell_list: [
{ n_id_cell: 2, dl_earfcn: 42590, cell_id: 0x1a2d102, tac: 0x0001 },
],
},], /* cell_list */
In ncell_list
, n_id_cell
is n_id_cell
of eNB2 and cell_id
is a concatenation of enb_id
and cell_id
of eNB2.
- Measurement configuration
You can make the UEs send measurement reports when the connection state fluctuates, so that the ORSs know when to trigger handover. For example, you can enter the following parameters :
/* Measurement configuration for handover */
meas_config_desc: {
a1_report_type: "rsrp",
a1_rsrp: -70,
a1_hysteresis: 0,
a1_time_to_trigger: 640,
a2_report_type: "rsrp",
a2_rsrp: -80,
a2_hysteresis: 0,
a2_time_to_trigger: 640,
a3_report_type: "rsrp",
a3_offset: 6,
a3_hysteresis: 0,
a3_time_to_trigger: 480,
},
/* measurement gap configuration */
meas_gap_config: "gp0",
/* if true, initiate a handover when a suitable measurement report is received */
ho_from_meas: true,