Multiplex communications – Communication techniques for information carried in plural... – Adaptive
Reexamination Certificate
1998-12-22
2003-02-11
Nguyen, Steven (Department: 2663)
Multiplex communications
Communication techniques for information carried in plural...
Adaptive
C370S335000, C370S479000, C370S328000
Reexamination Certificate
active
06519266
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to management techniques for a wireless communications network and, more particularly, to a system and method for layering a packet data service in the wireless communications network.
BACKGROUND OF THE INVENTION
There are many types of calls that are being performed in various telecommunications networks. The public switched telephone network (“PSTN”) handles voice calls between two voice terminals and has been adapted to handle data calls between two data terminals through use of modems and the like. Likewise, many data networks, such as the internet, handle data and voice calls between two terminals.
Wireless networks are also commonplace, and can connect to the PSTN through one or more mobile switches. Furthermore, the wireless networks can be connected to a data network through interface systems such as one using data interworking function technology. In this way, a mobile terminal operating in a wireless network can connect to a remote terminal through the wireless network and further through the PSTN or the data network.
For example, in
FIG. 1
, the reference numeral
10
designates a wireless telecommunications system
10
. In the present example, the network
10
is a cellular network or a personal communication service network that utilizes code division multiple access (“CDMA”) technology. The CDMA network
10
includes several components, including a mobile switching center (“MSC”)
12
, a base station controller (“BSC”)
14
, a home location register (“HLR”)
16
, and an interworking function system (“IWF”)
18
. It is understood that the components described in
FIG. 1
are merely exemplary, using terms that are well known in the telecommunications industry to represent only one type of component.
The components of the CDMA network
10
are connected in various methods, such as signaling system
7
(“SS7”), Ethernet, and so forth. To accommodate the various methods, the interconnections are illustrated in a functional sense. Therefore, it is understood that the descriptions of the components and interconnections therebetween are meant for exemplary purposes.
A first data device
20
is connected through a wireless link
30
to the CDMA network
10
using an IS-99 wireless communications device (not shown). IS-99 is a CDMA Circuit Switched Data Specification that defines how a CDMA mobile terminal establishes a circuit call through a modem pool of the IWF
18
. Other wireless communication devices can provide similar functionality, such as an IS-707 device. A second data device
24
is connected to a data network
26
. For the sake of further example, the first data device
20
is a laptop computer, the second data device
24
is a desktop computer, and the data network
26
is a packet data network (“PDN”).
The HLR
16
provides a database for storing customer profile information such as features, dialing capabilities, and a home serving area identification. In the present example, the home serving area identifies the MSC
12
in which the first data device
20
is located. One example of an MSC is a DMS-MTX MSC manufactured by Northern Telecom Ltd. of Montreal, Canada. The operation of the HLR
16
and the MSC
12
, along with other switching centers and databases not shown, is well known and understood in the art.
The IWF
18
provides several functions. For one, it establishes control signal communications with the laptop
20
using a predetermined protocol stack. The protocol stack is commonly used to support various communications in the wireless network
10
. The IWF
18
also supports a data connection to the remote data terminal
24
. The data connection can either be through the PSTN or through the PDN
26
.
The IWF
18
is able to establish a data path to the PDN
26
using a CDMA fast connect, or hybrid data call, connection. The IS-99 wireless terminal
22
of the first data device
20
connects with the BSC
14
through a wireless link
30
. The BSC
14
has a link
32
(either wireless or physical) to the MSC
12
. The MSC
12
then establishes a data path (e.g. using a data bus) and a signaling path (e.g., using Ethernet), collectively designated with a bus
34
, to the IWF
18
. The IWF terminates the signaling path with an IS-99 device and routes the data to the data network
26
.
The IWF
18
is also able to establish a data path to the PSTN using a CDMA circuit switched connection. With a circuit switched data path, the IWF
18
terminates the signaling path with an IS-99 device and routes the data to an internal modem pool (not shown). The data from the modem pool is then sent back to the MSC
12
on a bus
36
and from there to the PSTN through a trunk
38
. Once connected to the PSTN, several different gateways are available to the PDN
26
, such as through an internet service provider (also not shown).
CDMA technology, such as is used in the wireless network
10
of
FIG. 1
, is a continually evolving technology. In 2nd generation CDMA systems, when the data device
20
sends data over the CDMA network
10
, the device repeatedly performed the steps of: making a call, sending data, and hanging up. This inefficient use of system resources by making multiple calls is being addressed by a 3rd generation CDMA technology.
Standards for 3rd generation CDMA systems are currently being designed to include a medium access control (“MAC”) layer for handling layer specific functions. The proposed MAC layer controls access to the physical channels in the CDMA network
10
on which the data device
20
may arrange packets of data.
The MAC layer proposed for 3rd generation systems gets the data device
20
on and off a path or channel without making multiple calls. Instead of using “slots,” such as in time division multiple access networks, CDMA technology provides software-based logical channels through which data is sent. These logical channels, each of which may provide a different data service, can simultaneously exist on the same physical channel. The proposed MAC layer also serves to coordinate these different services.
A particular logical channel has transmission and reception characteristics and is restricted to carrying a certain set of information. During system operation, information on a logical channel is carried on a real physical channel, which is a radio channel employing CDMA technology. In this way, a logical channel is said to be mapped to a physical channel.
Logical channels are divided in two broad classes: common and dedicated. Common logical channels are mapped to common physical channels while dedicated logical channels are mapped to dedicated physical channels. A common physical channel is a CDMA based radio channel that may be shared between one base station and a plurality of mobile stations. A dedicated physical channel is a CDMA based radio channel that is assigned by a base station (for a period of time) to exchange information between exactly one base station and exactly one mobile station.
Referring to
FIG. 2
, the MAC layer proposed for 3rd generation systems attempts to get the data device
20
on and off a path or channel without making multiple calls. The proposed MAC layer operates according to a packet data service state diagram
100
. Each state of the state diagram
100
depicts different stages of packet data service and is associated with conditions of the network
10
. These conditions include permitted actions and the availability of specific logical channels.
The state diagram
100
for the proposed MAC layer is an enhancement of the 2nd generation packet data service (as described in IS-707) and includes a packet null state
102
, an initialization state
104
, a reconnect state
106
, an active state
108
, a control hold state
110
, a suspended state
112
, and a dormant state
114
.
The packet null state
102
is the initial state and corresponds to the absence of packet data service. In the packet null state
102
, no dedicated FL (Forward Link, from base station to mobile) or RL (Reverse Link, from mobile to base station) channels are allocated and no
Ghaleb Ibrahim
Gutierrez Alberto
Manning Serge
Duong Duc
Haynes and Boone LLP
Nguyen Steven
Nortel Networks Limited
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