Recommendation Q.1062





               DIGITAL PLMN ACCESS SIGNALLING REFERENCE CONFIGURATION





1     General


      This Recommendation provides the access signalling reference configuration for the digital 
PLMN.



2     Definitions


2.1   reference configurations

      Reference configurations are conceptual configurations useful in identifying various possible 
physical access arrangements to  the  PLMN.  Two  concepts  are  useful  in  defining
reference configurations: reference points and functional groups.


2.2   functional groups

      Functional groups are sets of functions which may be needed in PLMN access arrangements. In a 
particular access arrangement, a specific function in a functional group may  or  may
not be present. Note that a specific function in a functional group may be performed in 
one or more pieces of equipment.


2.3   reference points

      Reference points are the conceptual points dividing functional groups. In a specific access 
arrangement a reference point may correspond  to  a  physical  interface  (e.g.,  Um)
between pieces of equipment or there may not be any physical interface corresponding to the 
reference point.



3     Signalling reference configurations


3.1   The reference configurations for the PLMN access define reference points and types of functions 
that can be  provided.  Figure  1/Q.1062  shows  some  of  the  signalling  reference
configurations.

3.2   The Sm signalling reference point is the demarcation between RF transmission management and the 
combined functions of  call  control  and  mobility  management.  Similarly,  the  Xm
signalling reference point is the demarcation between call control and mobility management.

      The mobile station - base station Recommendations apply to interfaces at reference point Um. 
These Recommendations are dependent on the pertaining  RF  transmission  capabilities
and will not be dealt with in this document.

      At the reference point S, ISDN installations in accordance with I-Series Recommendations may be 
used. At reference point R,  physical  interfaces  in  accordance  with  other  CCITT
Recommendations   (e.g. the X-Series interface Recommendations) may by used.





                                  FIGURE 1/Q.1062
                                          
                        Signalling reference configurations




3.3   The list of functions for each functional group is given below.

3.3.1     The RF transmission management block may perform functions similar to those of NT1, or combined 
NT1 and NT2 of the CCITT I-Series Recommendations.

      It may include functions for:

      -   radio transmission termination(s); and

      -   upper layer protocol capabilities for radio transmission channel management.


3.3.2     The mobility management block may perform functions associated with:

      -   location updating/registration;

      -   handover coordination; and

      -   upper layer protocol capabilities for coordination functions between terminal equipment and 
          RF transmission management.


3.3.3     A TEm may perform functions similar to those of the TE of the I-Series Recommendations. It may 
include functions for:

      -   Layer 1 (physical) interface;

      -   Layer 2 (data link) protocol handling;

      -   Layer 3 protocol handling, and call control;

      -   maintenance functions; and

      -   switching and concentration (if applicable).

3.3.4     The PLMN call control adaptation block includes signalling related functions belonging to 
Layer 1 and higher layers of the Recommendation X.200 reference model that  allows  a
TE1 or TE2 terminal to be served by the  digital  PLMN.  It  may  also  include  rate
adaptation and flow control.



4     Physical realization of reference configurations


4.1   Mobile station implementations may require that the S, R, Xm and Sm reference points be combined into a single physical entity, as in the case of a fully integrated mobile 
equipment.

      Figure 2/Q.1062 shows possible realizations and/or configurations of the reference points 
mentioned earlier.  The  examples  shown  are  not  exhaustive,  but  only  serve  to
illustrate possible configurations of the respective functional blocks.


                                  FIGURE 2/Q.1062
                                          
                         Examples of physical realizations


4.2   Example a) of Figure 2/Q.1062 illustrates a fully integrated equipment where the Xm and Sm 
reference points are logically identifiable, but physically do not exist.


4.3   Example b) of Figure 2/Q.1062 illustrates the S reference point with respect to a CCITT TE1. In 
this example the PLMN  call  control  adaptation  function  is  integrated  with  the
remaining blocks as in a). As before the Xm and Sm reference points only bear logical 
significance.


4.4   Example c) of Figure 2/Q.1062 illustrates the same configuration as in b), but now a CCITT TE2 
is provided at reference point R. The PLMN call  control  adaptation  procedures  are
distinct with respect to the one identified in b), but nonetheless the functionality is 
the same as mentioned earlier.