The base stations within an ASN-GW group (i.e.,
all base stations connected to the same ASN-GW) are connected through
R8 reference point. Furthermore, the base stations within an ASN-GW group
are separately connected to the ASN-GW via
R6 reference point, as shown.
The base station is a logical entity that implements a
full instance of Medium Access Control (MAC) and Physical Layer (PHY)
protocols, as specified by the IEEE 802.16-2009 standard and includes
one or more access functions. A BS instance represents one sector with one
frequency assignment. It incorporates scheduler functions for uplink and
downlink radio resources, which are typically vendor specific.
The ASN-GW is a logical entity that represents
an aggregation of control functions that are either paired with a
corresponding function in the ASN (e.g., BS instance), a resident function
in the CSN, or a aggregation of control functions that are either
paired with a corresponding function in the ASN (e.g., BS instance),
a resident function in the CSN, or a function in another ASN. The ASN-GW
may also perform bearer-plane routing or bridging functions. A BS is
associated with a default ASN-GW; however, the ASN-GW functions may be
distributed among multiple ASN-GWs located in one or more ASNs.
The ASN functions in an ASN-GW can be divided into two
groups, i.e., the Decision Point (DP) and the Enforcement Point (EP)
functions. The EP category includes bearer-plane functions and the DP
category includes non-bearer-plane functions. If such functional
split is implemented in ASN-GW, the EP and DP functional groups would include
bearer-plane and non-bearer-plane functions, respectively, and
are interfaced using R7 reference point.
