TAI-based routing of handover (HO) and configuration transfer messages towards
Pico controller/HeNBGW when the target eNB ID is 28 bits, but it could not
support TAI-based routing when the target Pico eNB ID is 20 bits.
Pico controller can
transfer the target Pico eNB ID to 28 bits from 20 bits if the handover is
Pico-to-Pico, but it could not handle Macro-to-Pico handover as there is no
Pico Controller for Macro.
In releases 21.1 and
beyond, the behavior of MME is modified so that it can perform TAI-based
routing even if target home-eNB ID is 20 bits.
provides a configurable option within MME service to configure target HeNB type
(home or macro or both) behind HeNBGW. Based on this configuration, MME allows
TAI-based lookup of target eNB, if target eNB ID is not found by MME during
handover. By default, TAI-based lookup is performed only for home eNB ID
This feature is also
introduced to support identification of target eNB using target TAI for target
eNB type Macro or Pico nodes or both so that handover to such eNB can be
supported if it is connected to MME through Pico controller/HeNBGW. From MME
point of view, Pico controller is a Macro eNB which is using 20 bit eNB ID to
Along with S1 based
intra-MME HO, this feature can be applied to inter MME S1 HO procedures
(inbound S10, S3 and Gn handovers). Please note that, in Gn case, MME converts
target RNC ID to macro eNB ID so target TAI-based lookup for macro eNB works
This feature allows
operators to configure the global eNodeB IDs of HeNBGWs in the MME service. The
MME uses this information to perform HeNBGW related functions. In case of
S1-based handovers to home eNodeBs served by a HeNBGW, the lookup at MME for
the target eNodeB based on global eNB ID will fail, as MME is aware of only the
HeNBGW. In those cases, additional lookup needs to be done based on TAI to find
the HeNBGW serving the home eNodeB.
lookup for home or macro eNBs is supported for HeNBGWs, all such HeNBGWs should
be defined in HeNBGW management database (HeNBGW-mgmt-db). The HeNBGW-mgmt-db
should be associated within mme-service.
In this release, the
number of HeNBGW entries in the HeNBGW-mgmt-db has been increased from 8 to