Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
2001-02-05
2002-08-20
Hsu, Alpus H. (Department: 2665)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S338000, C370S349000, C370S410000, C455S517000
Reexamination Certificate
active
06438114
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a communication system, and in particular, the present invention relates to a method and apparatus for exchanging session initiation protocol signaling messages between a mobile station and a network for setup of multimedia calls.
BACKGROUND OF THE INVENTION
Setup procedures associated with multimedia calls placed by mobile terminals are performed using a recently developed signaling protocol commonly known as the session initiation protocol (SIP). In particular, the session initiation protocol is an open internet protocol (IP) standard designed specifically for initiating, managing, and terminating interactive IP sessions, such as, but not limited to Voice over IP sessions and multimedia conferences.
A current method for utilizing the session initiation protocol involves a Global System for Mobile Communications (GSM) approach, which utilizes the slow dedicated control channel (SDCCH) for channel signaling for setting up and maintaining a call. However, the amount of data transmitted by the slow dedicated control channel is a relatively small amount, i.e., 23 bytes, and may occur approximately every 120 milliseconds, while session initiation protocol messages average approximately 400 bytes of information per message. As a result, the amount of time necessary to transport a multimedia message between a mobile station and a mobile terminal using the slow dedicated control channel is excessively long, since many slow dedicated control channels would be required to pass the session initiation protocol message to and from the mobile station. In addition, additional setup time would also be required in order to set up a signaling link if one is not already available.
Another method currently proposed for utilizing the session initiation protocol involves using packet data channels to set up and maintain a virtual multimedia connection.
FIG. 1
is a data flow diagram of a session initiation protocol call setup sequence utilizing packet data channels. As illustrated in
FIG. 1
, prior to sending messages between a mobile station
100
and a network
102
, a temporary block flow (TBF)
104
must be set up. When utilizing packet data channels to set up and maintain the virtual media connection, once temporary block flow
104
is set up between mobile station
100
and network
102
, mobile station
100
transmits an INVITE command
106
to network
102
along a packet associated control channel (PACCH). Once network
102
receives INVITE command
106
, a temporary block flow
108
is again set up between mobile station
100
and network
102
, so that upon completion of the set up of temporary block flow
108
, network
102
responds to INVITE command
106
by sending a RINGING status command
110
to mobile station
100
along the packet associated control channel.
Once RINGING status command
110
is sent, a temporary block flow
112
is once again set up between mobile station
100
and network
102
to enable transmission of an OK acknowledgement message
114
from network
102
to mobile station
100
. Finally, a temporary block flow
116
is once again set up between mobile station
100
and network
102
to enable an acknowledge (ACK) message
118
to be sent from mobile station
100
to network
102
.
FIG. 2
is a data flow diagram of an uplink temporary block flow set up sequence between a mobile station and a network. As illustrated in
FIG. 2.
, during the set up of each of temporary block flows
104
,
108
,
112
and
116
, mobile station
100
sends a channel request access burst
120
to network
102
using a random access channel (RACH). Network
102
responds by sending an immediate assignment message
122
along an access grant channel (AGCH) to mobile station
100
. Mobile station
100
then sends a packet resource request message
124
along the packet associated control channel to network
102
requesting resources for the temporary block flow. Network
102
responds with a packet uplink assignment message
126
, which is acknowledged by mobile station
100
in a packet control acknowledge message
128
. Note that while the temporary block flow set up sequence shown in
FIG. 2
is in the uplink direction, i.e., from mobile station
100
to network
202
, a downlink temporary block flow set up sequence is similar, with the major exception being that network
102
initially pages mobile station
100
.
Since a temporary block flow set up sequence can typically take approximately 1.7 seconds or more to complete, a relatively large amount of time is needed for set up of temporary block flows
104
,
108
,
112
and
116
, so that the use of packet data channels to set up and maintain a virtual multimedia connection, as shown in
FIG. 1
, tends to require excessive set up times for multimedia calls as well.
As a result of the excessive call set up times required by current methods for utilizing session initiation protocols, excessive delays tend to occur when calls are maintained by the exchange of control information. Likewise, current methods also tend to result in control channel congestion since they require excessive utilization of radio resources due to the fact that session initiation protocol control messages are designed for wireline use, and each time a control message is sent in order to set up, tear down, or maintain a multimedia session, a large exchange of signaling information will necessarily have to occur just to enable the flow of such information.
Accordingly, what is needed is a more efficient method and apparatus for the interchange of session initiation protocol signaling messages between a mobile station and a network for setup of multimedia calls by the mobile station.
REFERENCES:
patent: 5901142 (1999-05-01), Averbuch et al.
patent: 6026086 (2000-02-01), Lancelot et al.
patent: 6094429 (2000-07-01), Blanchette et al.
patent: 6282193 (2001-08-01), Hluchyj et al.
“Direct APPN Sessions Using Dynamic Address Resolution On Lans”, IBM Technical Disclosure Bulletin, Jan. 1, 1991, vol. 33, No. 8, pp. 32-35.*
“NetBIOS Local Area Network Access Agents”, IBM Technical Disclosure Bulletin, Dec. 1, 1993, vol. 36, No. 12, pp. 417-422.*
“SIP: Session Initiation Protocol”, (Internet Engineering Task Force (IETF); M. Handley, H. Schurzrine, E. Schooler, J. Rosenberg), Mar., 1999.
“A comparison between GERAN packet-switched call setup using SIP and GSM circuit-switched call setup using RIL3-CC, RIL3-MM, RIL3-RR and DTAP”, (Tdoc GP00036; TSG GERAN; Nortel), Aug. 28th, 2000.
GSM 04.60, “Digital cellular telecommunications system (Phase 2+); General Packet Radio Service (GPRS); Mobile Station (MS)—Base Station System (BSS) interface; Radio Link Control/Medium Access Control (RLC/MAC) protocol”, (European Telecommunications Standards Institute (ETSI), Global System for Mobile Communications (GSM) specifications).
GSM 04.18, “Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification, Radio Resource Control Protocol”, (European Telecommunications Standards Institute (ETSI), Global System for Mobile Communications (GSM) specifications).
3GPP 24.007, “3rdGeneration Partnership Project (3GPP); Technical Specification Group Core Network (TSG CN); Mobile radio interface radio network signally layer 3; General aspects”, (3rdGeneration Partnership Project; Telecommunications Standard).
Howell Andrew
Pecen Mark
Womack James E.
Hsu Alpus H.
Motorola Inc.
Soldner Michael C.
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