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1. Introduction
In the fiercely competitive telecom market, winning customer,
especially large customers often means the increase of profit and
revenue. According to the so called '2 and 8 principle', which means
that the 20% large customers will bring the 80% revenue to a business,
retaining large customers and increasing their usage volume will
be an important marketing task in the telecom market. However, in
the current mobile communications market, high tariffs and inconvenient
applications often keep users from using mobile services. To overcome
these disadvantages, local mobile companies nationwide will soon
roll out virtual private mobile network (VPMN) service according
to the centralized plan of their common group company.
2. VPMN Service in Brief
VPMN service is a service which allows group users to communicate
with each other through abbreviated numbering or dedicated numbering
plans over a private network of logic voice circuits, based on the
public land mobile network (PLMN) and the public fixed telephone
network (PSTN). VPMN service operated in the PLMN provides the mobile
users in the user groups that have subscribed to the service with
private network service similar to PBX service in the PSTN.
VPMN service allows its users to make intra-network calls, outside
network calls and closed user group calls, and use dedicated numbers
and abbreviated numbers. When all the network elements are upgraded
to support a target network of CAMEL Phase2, MAP Phase 2+ and beyond,
VPMN service supports roaming. Besides, VPMN service can give certain
favorable treatment to the basic, roaming and total charges, thus
saving call charges for businesses and retaining large customers
for mobile operators.
3. Networking Modes and Requirements
To
deploy VPMN service smoothly, it is necessary to transform the existing
network in the following ways.
1)
To build new SCPs, used to load VPMN service logic so as to build
a network of logical circuits on the basis of the PLMN, providing
the users with functions of dedicated numbering and abbreviated
number dialing and taking charge of billing.
2)
To upgrade the existing network so as to allow the MSC to have SSP
function and trigger service according to the user's contracted
information (0/T-CSI), which is located in the user's HLRs and inserted
into the VLRs while the user is roaming.
3)
To transform the BOSS system so as to enable it to execute VPMN
service handling, accounting and statistics and add interfacing
function between the VPMN and the SMPs and provide management of
the users of the group by WWW terminals.
4. Features of VPMN Service
1)
Flexible Numbering Plan (Short Numbers)
Business
or groups which have subscribed to VPMN service may establish their
own internal short numbering plans. To facilitate memory and management,
a short number may identify a unique group member (information like
position and job number). The change of the group member's real
number will not affect the short number numbering plan so that members
of the group can communicate with each other all the same. They
only need to remember the internal short numbers to call the intended
colleagues. When the short number numbering plan has changed, including
the change of the real numbers corresponding to the VPMN numbers,
the addition of new real numbers or VPMN numbers, etc., the group
in question should inform the mobile operator of the change and
the operator should change the service data accordingly. The short
numbers of one group can only be used to call users of the same
group.
2)
Flexible Classification and Charging Plan
The
user can classify calls into, for example, closed user group calls,
intra-network calls, outside network calls and inter-network calls.
Mobile operators can give certain favorable treatment to the basic,
roaming and total charge on a discounted, fixed or flat-rate basis,
depending on different call classes. Besides, different tariffs
may be established on the basis of duration and location of calls
made and received.
3)
Long or Short Number Display
According
to the setting of the user, the called user may choose the real
or short number of the calling user of the same group as the calling
number to be displayed, and may call back by dialing the number
chosen. As to calls between cross-provincial user groups, there
is no inter-provincial short number numbering plans. Users of cross-provincial
groups have to use and display real numbers for intra-network calls.
4)
Flexible Dialing Mode
For
intra-network calls, the VPMN use can either dial the short number
defined by the group or the real number of the called user. The
system can set up the connection and charge according to the dialing
mode used and the conditions of the called user.
5)
Flexible Call Control
The
group can perform call control through authority management so as
to limit its users to a specific class of calls. At present, only
calling authority and called authority are provided by VPMN service.
6)
System Barred Numbers
The
VPMN may set up barred numbers. No users in all the groups which
have subscribed to VPMN service can dial these numbers. To be more
specific, if the user dial any system barred number in the long
number mode, the call will be connected normally and no favorable
treatment is given. If the user dial any system barred number in
the short number mode, the call will not be connected.
7)
Support to Additional Services and Telecom Services
The
additional services and telecom services supported by VPMN service
include short message service, calling number display (In the case
of intra-network calls, internal short numbers of the calling VPMN
group can be displayed; otherwise the real numbers of the calling
users are displayed), calling number hiding, call forwarding, call
waiting, mobile secretary, IP telephone. These services need support
from the existing network.
8)
Diverse Management Means
At
present, the VPMN system provides two service management modes.
One is the voice inquiry and management mode, to be used by the
managers of the VPMN individual and group users; the other is the
management mode of dedicated management terminals and WWW terminals,
to be used by the managers of the VPMN group users and operators.
9)
Service Management Functions
Group management function: The VPMN system provides centralized
management of VPMN groups. System management includes group application
for service, group service blocking, group service reactivation,
group service validity management, inquiry of group service information
(status), group service information (status) update, group operator
and manager setting/modification/inquiry/deletion, CUG management
(setting/modification/inquiry/deletion), etc.
VPMN
user management function: It includes user addition/deletion, user
authority update ans user maximum call charge setting/inquiry/ updating.
10)
Flexible Call Charge Control and Account Management
The
group may control its call charge through account management. At
present, VPMN service provides the user with two accounts: the individual
account and the group account beside the ordinary individual account
the GSM user already has. This enables the user to control and manage
his or her call charges flexibly and effectively.
11)
Support to Cross-provincial Group Users
Cross-provincial
group users may use the same service features as their intra-provincial
counterparts, except that they have to establish their short numbers
and set group operators and managers on a provincial basis.
5. The Trend of VPMN Service
As
telecom networks develop, they will get more and more complex. How
to provide users with transparent service between the fixed, GSM
and CDMA networks and the Internet is an important issue in developing
new services including VPMN service. The next topic and step will
be how to incorporate the fixed and Internet users into VPMN service
logic and evolve to an integrated VPN. After the upgrade of the
target network, VPMN service will be provided to GSM users only,
limited by the contracted information (0/T-CST) supported by switch
manufacturers. With the gradual expansion of intelligent services,
users' demand for intelligent services will go diverse and VPMN
service will converge various intelligent services.
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