Multiplex communications – Data flow congestion prevention or control – Flow control of data transmission through a network
Reexamination Certificate
1999-01-15
2002-09-17
Patel, Ajit (Department: 2664)
Multiplex communications
Data flow congestion prevention or control
Flow control of data transmission through a network
C370S310200, C370S395600, C370S469000
Reexamination Certificate
active
06452904
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to operation and maintenance (OAM) activities within a cellular communications network and, in particular, to the specification of OAM flows for A-interface connections.
2. Description of Related Art
Reference is now made to
FIG. 1
wherein there is shown a schematic diagram of a cellular telephone network
10
including a plurality of interconnected switching nodes (SN)
12
. Although only two switching nodes
12
are shown, it will be understood that the network
10
likely includes many more interconnected nodes. The first and second switching nodes
12
(
1
) and
12
(
2
) may comprise any one of a number of known telecommunications switching devices, including mobile switching centers (MSC's), as commonly used and known in the art for providing either digital or analog cellular telephone service to a plurality of mobile stations (MS)
14
. The switching nodes
12
are interconnected with each other for communication via both voice trunks
18
(illustrated with broken lines) and signaling links
16
(illustrated with solid lines) providing a known ISUP (or R
1
or R
2
) type connection. The voice trunks
18
provide voice and data communications paths used to carry subscriber communications between the switching nodes
12
. The signaling links
16
carry command signals between the switching nodes
12
. These signals may be used, for example, in setting up and tearing down voice and data communications links over the voice trunks
18
and controlling the provision of calling services to the mobile stations
14
. The switching nodes
12
are also connected to a data base
20
comprising a home location register (HLR) by means of signaling links
22
providing a known Mobile Application Part (MAP) or IS-41 type connection. The data base
20
stores information concerning the mobile stations
14
comprising location information and service information.
Each of the switching nodes
12
is further connected to at least one associated concentration point (CP)
24
via both a signaling link
26
and a voice trunk
28
. The voice trunk
28
provides a voice and data communications path used to carry subscriber communications between each switching node
12
and its associated one or more concentration points
24
. The signaling link
26
carries command signals between the node
12
and its associated concentration point
24
. The signaling link
26
and trunk
28
are collectively commonly referred to in the art as the “A interface”. Each concentration point
24
is then connected to a plurality of base stations (BS)
30
which operate to effectuate radio frequency communications with proximately located mobile stations
14
over an air interface
32
.
As a basic functionality, each concentration point
24
performs necessary switching operations to route communications (traffic or control) between the signaling link
26
and trunk
28
and the base stations
30
. As an enhanced functionality, each concentration point
24
may further perform radio network control (RNC) operations (such as mobile station locating, radio frequency channel allocation, handoff control, and local mobile station to mobile station call set-up) in a well known manner to control mobile radio frequency communications operation. When both the basic and enhanced functionalities are present, the concentration point
24
is referred to in the art as a base station controller (BSC). When both functionalities are not present, typically the concentration point
24
routes, and the switching nodes
12
implement the radio network controller operations.
The concentration points
24
may also be interconnected with each other via both a signaling link
34
and a voice trunk
36
. The voice trunk
36
provides a voice and data communications path used to carry subscriber communications between the concentration points
24
. The signaling link
34
carries command signals between the concentration points
24
. The signaling link
34
and trunk
36
, when present, are included within the “A interface”. These connections are advantageously utilized in certain situations (such as at intra-switching node handoff or mobile station to mobile station call set-up) to by-pass the switching node
12
and more efficiently support the provision of cellular service to the mobile stations.
Although direct communications links (signaling and/or trunk) are illustrated in
FIG. 1
, it is understood by those skilled in the art that the links are not necessarily direct between the illustrated nodes, and may instead pass through many other communications nodes (not shown) of the mobile network, and perhaps even utilize other communications networks (such as the public switched telephone network—PSTN). Illustration of the links in the “virtual” manner shown in
FIG. 1
is therefore by way of simplification of the drawing. The cellular telephone network
10
may comprise a Global System for Mobile (GSM) communications, an Advanced Mobile Phone System (AMPS), a digital Advanced Mobile Phone System (D-AMPS), a code division multiple access (CDMA) system, or the like.
Prior to the definition of the A-interface, the connection between the switching node
12
and concentration point
24
was proprietary and vendor specific. This forced a cellular service operator/provider to purchase all the equipment from the same source. The premise behind the development of the A-interface concept is to support a multi-vendor environment for cellular network equipment. With the specification of a standardized interface between the switching nodes
12
and the concentration points
24
, a cellular service operator/provider could purchase its needed equipment from different vendors and easily interconnect that equipment.
The Telecom Industry Association (TIA) sub-committee TR45.4 is currently finalizing a definition for the A-interface (see, Interim Standard IS-634, rev. A). This standard describes the overall system functions between the switching nodes
12
and the concentration points
24
relating to the services and features required for the interface.
The A-interface includes a plurality of sub-interfaces. A first sub-interface (A
1
) carries signaling (see, signaling link
26
) through the concentration point
24
between a call control (CC) function and mobility management (MM) function within the switching node
12
and the call control (CC) component of the base station
30
. The A
1
sub-interface supports short message service (SMS) messaging and over the air activation service provisioning (OTASP) using OTA data messages as defined in Interim Standard IS-683 sections 3.5 and 4.5. A second sub-interface (A
2
) carries 64 kbit/sec pulse code modulation (PCM) information (voice/data) over the trunk
28
between the switch component of the switching node
12
and either the channel element component of the base station
30
(for an analog air interface) or the selection/distribution unit (SDU) of the base station
30
(for a digital air interface). A third sub-interface (A
3
) carries coded user information (voice/data) frames and signaling between the selection/distribution unit (SDU) and the channel element component of the base station
30
. The A
3
sub-interface is composed of two parts: a signaling connection; and a user traffic connection. The signaling connection is carried across a separate logical path from the user traffic connection and controls the allocation and use of the logical paths for user traffic connections. A fourth sub-interface (A
4
) carries signaling between the call control component (CC) and the selection/distribution unit (SDU) of the base station
30
. The A
3
sub-interface is utilized to carry traffic between two concentration points
24
over the trunk
36
. The A
4
sub-interface is utilized to carry signaling between two concentration points
24
over the signaling link
34
. A fifth sub-interface (A
5
) carries a full duplex stream of bytes between the inter-working function (IWF) of the switching node
12
and the
Patel Ajit
Telefonaktiebolaget L M Ericsson (publ)
LandOfFree
Operation and maintenance flow support for A-interface... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Operation and maintenance flow support for A-interface..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Operation and maintenance flow support for A-interface... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2905469