AU732013B2 - Method for setting up a call in a cellular system - Google Patents
Method for setting up a call in a cellular system Download PDFInfo
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- AU732013B2 AU732013B2 AU50117/99A AU5011799A AU732013B2 AU 732013 B2 AU732013 B2 AU 732013B2 AU 50117/99 A AU50117/99 A AU 50117/99A AU 5011799 A AU5011799 A AU 5011799A AU 732013 B2 AU732013 B2 AU 732013B2
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- base station
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- 230000001413 cellular Effects 0 claims description title 40
- 238000004891 communication Methods 0 claims description 60
- 230000004044 response Effects 0 claims description 20
- 230000015654 memory Effects 0 claims description 9
- 238000000034 methods Methods 0 claims description 8
- 230000000977 initiatory Effects 0 claims description 6
- 239000010941 cobalt Substances 0 claims description 2
- 238000005225 electronics Methods 0 claims description 2
- 238000009740 moulding (composite fabrication) Methods 0 claims description 2
- 230000000717 retained Effects 0 claims description 2
- 238000005516 engineering processes Methods 0 description 4
- 230000033228 biological regulation Effects 0 description 1
- 230000000694 effects Effects 0 description 1
- 230000001360 synchronised Effects 0 description 1
Description
*1 P/00/011 28/5/91 Regulation 3.2
AUSTRALIA
Patents Act 1990
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Actual Inventor Address for service is: Samsung Electronics Co, Ltd Ik-Han Kim WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000
V.
Attorney code: WR Invention Title: "Method For Setting Up A Call In A Cellular System" The following statement is a full description of this invention, including the best method of performing it known to me:- -2-
TITLE
"Method For Setting Up A Call In A Cellular System" FIELD OF THE INVENTION The present invention relates to a method for setting up a call in a cellular system.
More specifically, this present invention is a method for setting up a call between a calling party and a called party in a cellular system using a code division multiple access (CDMA) technology.
DESCRIPTION OF RELATED ART In a cellular system, total coverage area is divided to a number of areas controlled by base stations and each base station area has a number of cell areas. A cell S• area is the smallest service area of a cellular system.
A mobile switching centre (MSC) controls said base stations and enables a call to continue even when a mobile telephone moves between cells or base stations.
Fig. 1 illustrates one structure of a cellular system using code division multiple access (CDMA) technology. As illustrated in the figure, the cellular system o• comprises a number of base stations (20, 30, 40) each of which provides call services to mobile station (MS) and a mobile switching centre (MSC, which connects the base stations to a public switched telephone network (PSTN, A cellular system may have more than one MSC.
In the above cellular system, a radio communications link from the base station to the mobile station is called to a forward link and a radio communications link from the mobile station to the base station is called to a reverse link.
A base station supporting CDMA technology uses a number of channels for each link including a pilot channel, a synchronous channel. a paging channel and a traffic channel for the forward link and an access channel for the reverse channel.
The base station uses apparatus called a channel element (CE) for operating these channels. Each channel element operates by one of the above channels.
If mobile station requests a call, it tries to set up communications with its base station that will enable it to establish an outgoing call to another mobile station or the PSTN.
Fig. 2 is a flow chart for illustrating a known method for setting up a call, either an originating call or for terminating an inbound call.
A mobile station (10) sends a call origination page response message to a base station control processor (BCP, 24) of the base station through an access channel element (ACH, 22) of the base station (step 1).
The base station control processor sends a message requesting a resource assignment to a mobile switching centre (MSC) (50) and also sends an °acknowledgment message for the call origination page message to the mobile station through a paging channel element (PCH, 23) (step 3).
The MSC (50) searches information on the subscriber requesting the resource assignment and sends a channel assignment message to the base station control processor (24) if the subscriber can receive a call service (step 4).
After sending a channel assignment message to the mobile station through the paging channel element, the base station processor selects one of the above traffic channels available for use in the base station and sends a traffic assignment message to the selected traffic channel element (step 4).
The traffic channel element (21) sends a null traffic message (a message having no call data) to the mobile station and informs the mobile station of the traffic channel assigned for connecting the call, by transmission of a "null traffic" message the assigned traffic channel.
The mobile station transmits a preamble message to the traffic channel element in -4order to inform it that the mobile station is ready to establish a call having received the null traffic message.
The traffic channel element having received the preamble message from the mobile station then sends a "mobile acquisition" message to the base station control processor (step 8 and 9).
The mobile station and the base station then processes a call by exchanging voice data.
The base station control processor simultaneously operates a timer having a predetermined operating time (for example, 5 seconds) so as to send channel assignment messages to the mobile station through the paging channel element (step 6).
If the propagation conditions of the channel are poor, the mobile station may not receive the channel assignment message transmitted by the paging channel element.
In which case, the mobile station may not receive the null traffic message of the traffic channel element since the mobile station can not switch from the paging channel to the traffic channel. Also the base station can not detect a signal from the mobile station as the mobile station can not transmit a preamble message to the base station.
After sending the channel assignment message (in step the base station control processor ignores all actions executed in the preceding steps and sends a release message to the traffic channel element in order to cancel the call (step if the mobile acquisition message is not received until after the timer has expired.
However, in the above case, the base station has already requested a call set up procedure be executed which has assigned resources from the mobile switching centre and/or the public switched telephone network.
Therefore, some resources have already been assigned to the base station, the mobile switching centre and the public switched telephone network which should be removed when the mobile station does not receive the channel assignment message.
As in the above, the prior known method for setting up a call does not provide effective use of the resources of the cellular communications network and may cause low traffic rates due to failure of call set up procedures.
DISCLOSURE OF THE INVENTION According to a first aspect of the present invention there is provided a method for setting up a call in a cellular system having a base station for transmitting and receiving radio messages with mobile stations, and a mobile switching centre for connecting the base station to another base station or a public switched telephone network, the method comprising the steps of: the base station receiving a request to originate a call from a mobile station; the base station requesting a resource assignment from the mobile switching centre; the base station sending an acknowledgment message to the mobile station from the assigned resource; the base station sending a channel assignment message to the mobile station; the base station operating a timer after sending the channel assignment message to the mobile station; the base station sending a null traffic message informing the mobile station of an assigned state of the traffic channel; -6receiving an acquisition message from the mobile station in response to transmission of the "null traffic" message; the base station connecting call traffic to the mobile station if the acquisition message from the mobile station is received before the timer has expired; and the base station re-sending the channel assignment message to the mobile station if the acquisition message from the mobile station is not received until the timer has expired.
Preferably said method further includes the step of storing information relating to the mobile station upon operating the timer.
Preferably the step for re-sending the channel assignment message is executed after searching information stored in relation to the mobile station.
According to a second aspect of the present invention there is provided a method Sofor a mobile station to set up a call in a cellular system having a base station exchanging radio messages with the mobile station, the method comprising the steps of: the mobile station transmitting a request to a base to originate a call; the mobile station receiving an acknowledgment message from the base station; the mobile station operating a timer in response to receiving said acknowledgment message; the mobile station connecting call traffic to the base station if a null traffic message is received from the base station before the timer expires; cancelling the call if the null traffic message is not received before the timer expires.
-7- According to a third aspect of the present invention there is provided a method for setting up a call in a cellular system having a mobile station offering a call service to a subscriber, a base station exchanging radio messages with the mobile station, and a mobile switching centre for connecting the base station to another base station or a public switched telephone network, the method comprising the steps of: a base station receiving a request from a mobile station to set up a call; the base station sending a channel assignment message to the mobile station; S..oo.
the base station re-sending the channel assignment message to the mobile station if the base station does not receive an acquisition signal from the mobile station within a predetermined time of the base station sending the channel assignment message.
Preferably the step for sending the channel assignment message further comprises the steps of: 00 the base station generating the channel assignment message using information stored in relation to the mobile station; the base station sending the generated channel assignment message to the mobile station; the base station storing the information on the mobile station in a memory.
Preferably the step for re-sending the channel assignment message further comprises the steps of: the base station searching information stored in relation to the mobile station; the base station using the searched information to re-generate a channel -8assignment message; sending the re-generated channel message to the mobile station.
According to a fourth aspect of the present invention there is provided a method for setting up a call in a cellular system having a mobile station offering a call service to a subscriber, a base station exchanging a radio message to the mobile station, and a mobile switching centre for connecting the base station to another base station or a public switched telephone network, the method comprising the steps of: :a base station receiving a request from a mobile station to set up a call with the base station; the base station requesting a resource assignment for the mobile switching centre; the base station sending an acknowledgment signal to the mobile station; 0o 0 the mobile switching centre assigning a channel to the mobile station; *the base station sending a channel assignment message to the mobile station; the base station retaining resources assigned to the mobile station in communication with the mobile station and the mobile switching centre if the base station sending the channel assignment message does not detect an acquisition signal from the mobile station within a predetermined time period.
Preferably the resources assigned to the mobile station are retained until a second predetermined time has expired after the base station transmits an acknowledgment message to the mobile station.
Preferably the method further includes the step of re-sending the channel assignment message to the mobile station if the base station sending the channel assignment message does not detect a mobile acquisition signal within the first predetermined time period.
Preferably the method further includes the step of the base station storing information in relation to the mobile station in a memory upon the base station sending the channel assignment message to the mobile station.
Preferably the method further includes the step of searching information stored in relation to the mobile station by the base station if the base station sending the channel assignment message does not detect a mobile acquisition signal within ***the first predetermined time Preferably the method further includes the step of re-sending the channel assignment message to the mobile station by using the result of the search of information stored in relation to the mobile.
According to a fifth aspect of the present invention there is provided a method of operating a cellular communications network comprising at least one base station adapted to communicate with mobile stations; the method comprising the steps of said at least one base station: 0 1) receiving a communication from a mobile station for initiation of call setup procedure; 2) transmitting at least one communication to said mobile station in response to receiving said communication at step 1); 3) monitoring communications received from said mobile station; 4) transmitting at least a second communication to said mobile station in response to said base station failing to receive at least one predetermined communication from said mobile station at step 3).
Preferably said at least a second communication comprises a re-transmission of said at least one communication transmitted at step 2).
Preferably step 4) is executed after a pre-determined period of time from transmission of said message at step 2).
Preferably said at least one communication transmitted by said base station comprises a channel assignment communication.
Preferably said pre-determined communication received from said mobile station comprises an acquisition communication.
Preferably said pre-determined period of time is measured from transmission of said at least one communication in step 2).
*o Preferably said at least one base station activates a timer upon transmission of said at least one communication and wherein said second communication is transmitted in response to said base station failing to receive said pre-determined communication from said mobile station before expiry of said timer.
Preferably said at least one communication in step 2) is stored by said base station in a memory and retrieved from said memory whereby forming said second communication in step 4).
According to a sixth aspect of the present invention there is provided a method of operating a mobile station for use in a cellular communications system, the method comprising the steps of: 1) transmitting a first communication to a base station of a cellular communication system for initiating a call set-up procedure with said base station; 2) receiving at least a second communication from said base station in response to said first communication transmitted by said mobile station; 3) the mobile station cancelling said call if said mobile station fails to -11 receive a third communication from said base station.
Preferably said second communication from said base station comprises a channel assignment communication. Preferably said third communication comprises a null traffic message.
Preferably said mobile station is adapted to connect call traffic to said base station in response to receiving said third communication.
Preferably said mobile station cancels said call upon failure to receive said third communication after a pre-determined period of time.
preferably said pre-determined period of time is determined by said mobile station initiating a timer in response to receiving said second communication from said base station.
S"According to a seventh aspect of the present invention there is provided a base station for a cellular communications network operated according to any one of the above methods for operating a network or base station.
o According to an eighth aspect of the present invention there is provided a mobile station for use in a cellular communications network adapted to operate according to any one of the above methods for operating a mobile station.
BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention shall now be described, by way of example only and with reference to the accompanying drawings in which: Fig. 1 illustrates a structure of the conventional cellular system using a code division multiple access (CDMA) technology; Fig. 2 is a flow chart for illustrating a known method for setting up a call; Fig. 3 illustrates a structure of the cellular system according to the present invention; -12- Fig. 4 is a flow chart for illustrating a method for setting up a call in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to Fig. 3 which illustrates an embodiment of the structure of the cellular system A mobile station (10) is connected to a number of channel elements of a base station (20) through a radio link.
A base station control processor (24) transmits to or receives call data from the mobile station, such as voice data, through a traffic channel element (21) and receives a communication control message from the mobile station through an access channel element The base station control processor (20) transmits communication control messages to the mobile station through a paging channel element (23).
The mobile station (10) starts a mobile station timer having a predetermined operating time (for example, 12 seconds), response to receiving "acknowledgment" message from the base station for a "call origination" "page response" message used in setting up a call with the base station.
S. The mobile station then waits for a channel assignment message from the base station until the mobile station timer has expired.
If a call is not connected before the mobile station timer has expired, the mobile station cancels the call and a "channel assignment" message is re-sent prior to a mobile station timer expiring.
This may be achieved by the base station storing an identical "channel assignment" message in a memory when the base station first sends a "channel assignment" message to the mobile station.
If the mobile station does not receive the "channel assignment" message from the base station, for example due to poor conditions on the forward link, the base -13station re-sends the stored channel assignment message to the mobile station.
The base station starts a base station timer when the base station sends a "channel assignment" message.
If a "preamble" message is not received from the mobile station before the base station timer has expired, the base station re-sends the "channel assignment" message.
If the state of the forward link is now better, the mobile station should receive the channel assignment message and then send a "preamble" message to the base 0 station to establish the call between the base station and the mobile station.
*•oo6 000 Fig. 4 is a flow chart illustrating a method of an embodiment for establishing a call.
If a subscriber requests a call be established, the subscriber's mobile station 00 0 °9 sends a "call origination" "page response" message to the base station control 0 processor (BCP, 24) whether the subscriber is originating a call or answering an ,inbound call. The message is sent to the base station control processor (BCP,
I
66, 24) through an access channel element (ACH, 22) of the base station (20) (step 110).
0. 0The base station control processor then requests a resource assignment from the mobile switching centre (MSC) (50) (step 120) and sends an "acknowledgment" message to the mobile station via the base station paging channel element (PCH, 23) (step 130).
The mobile station receives the "acknowledgment" message from the paging channel element of the base station and starts a mobile station timer.
The MSC (50) requests a resource assignment for establishing the call and commences a search of information on the subscriber. The channel assignment is allowed if the subscriber qualifies for call service. The base station control processor then sends a "channel assignment" message to the mobile station 14through the paging channel element (step 140).
If due to the conditions on the forward link of the mobile station, the mobile station does not receive the "channel assignment" message the mobile station can not transfer to the assigned traffic channel as it does not have requisite information from the "channel assignment" message.
Therefore, the base station control processor re-sends the channel assignment message (step 140), and re-starts the base station timer (step 150) and stores 0*oo information on the mobile station.
.After sending the "channel assignment" message to the mobile station, the base station control processor selects a useable traffic channel element (TCH) and informs the mobile station of the traffic channel assigned by sending a null traffic message through the traffic channel element (step 160).
The mobile station upon receiving the "null traffic" message sends a "preamble" message through the traffic channel element and the traffic channel element receives the "preamble" message and sends an "acquire" message to the base :station control processor.
After the base station control processor receives the "acquire" message (step the base station connects a call to the mobile station (step 210).
But if the mobile station does not receive the "channel assignment" message due to conditions on the forward link, the mobile station can not receive the "null traffic" message and therefore can not send the "preamble" message (which is an acknowledgment of the "null traffic" message) to the traffic channel element of the base station.
If the "acquire" message is not received from the traffic channel element until after the base station timer has expired (step 180), the base station control processor searches the information stored in the base station in relation to the mobile station and re-generates the "channel assignment" message by using the result of the search (step 190). The "channel assignment" message is then re-sent to the mobile station (step 200).
If the forward link of the mobile station is now good, the mobile station receives the re-sent "channel assignment" message and transfers from the paging channel to the traffic channel.
The base station control processor that re-sent the channel assignment message then selects a traffic channel element (TCH) and sends a "traffic channel assignment" message to the selected traffic channel element.
The traffic channel element then sends a "null traffic" message to the mobile station.
The mobile station then informs the base station that it is ready to receive a call by sending a "preamble" message to the traffic channel element. The traffic channel element then sends a "mobile acquire" message to the base station control processor in order to connect to the call with the mobile station.
The mobile station that received the "acknowledgment" message from the base station (step 130) then initiates a mobile station timer. The mobile station timer automatically cancels the call if the "null traffic" message is not received from the base station before the mobile station timer expires. This prevents assignment of resources by the MSC that are not utilised due to failure of the call set up procedure at the mobile station.
Once the base station has re-sent the channel assignment message to the mobile station for the second time it does not re-store the information as the call set up procedure is deemed to have failed if the base station timer expires for a third time.
An effect in accordance with the present invention is as follows.
If the mobile station does not receive a channel assignment message due to poor -16conditions on the forward channel, resources connected to the base station, mobile switching centre and public switched telephone network for establishing a call are not wasted since the base station re-sends a channel assignment message before the mobile station timer expires and the call is cancelled.
Therefore, the resources between the base station and the mobile station and the resources in a system can be utilised more effectively allowing the traffic rate to be raised.
Claims (28)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR98/039354 | 1998-09-23 | ||
| KR1019980039354A KR100300348B1 (en) | 1998-09-23 | Method for call setup in cellular system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU5011799A AU5011799A (en) | 2000-04-06 |
| AU732013B2 true AU732013B2 (en) | 2001-04-12 |
Family
ID=19551564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU50117/99A Ceased AU732013B2 (en) | 1998-09-23 | 1999-09-23 | Method for setting up a call in a cellular system |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN1136675C (en) |
| AU (1) | AU732013B2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7180879B2 (en) | 2001-08-17 | 2007-02-20 | Ragulan Sinnarajah | Method and apparatus for call setup latency reduction |
| CN100387091C (en) | 2003-09-22 | 2008-05-07 | 华为技术有限公司 | Method of carrying out fast calling setup |
| CN100428835C (en) | 2004-08-18 | 2008-10-22 | 华为技术有限公司 | Method for obtaining mobile phone position information |
| CN100459795C (en) | 2005-06-15 | 2009-02-04 | 华为技术有限公司 | Method for selecting service node according to load status |
| KR100677511B1 (en) | 2005-08-12 | 2007-01-26 | 엘지전자 주식회사 | Bcast service system and contents transmitting method using the same |
| CN100536596C (en) | 2005-09-02 | 2009-09-02 | 中兴通讯股份有限公司 | Method for improving call performance of CDMA system |
| CN101083821B (en) | 2006-05-30 | 2010-05-12 | 华为技术有限公司 | Method for processing abnormality of POC service and POC server |
| CN100574276C (en) | 2006-08-22 | 2009-12-23 | 中兴通讯股份有限公司 | Control method for reinforcing uplink random access in time division synchronization code division multiple access system |
| KR20090026739A (en) * | 2007-09-10 | 2009-03-13 | 삼성전자주식회사 | Method for allocating resource and receiving data |
| CN101562836A (en) * | 2008-04-18 | 2009-10-21 | 中兴通讯股份有限公司 | Retransmission method of base station response message |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998031178A1 (en) * | 1996-12-23 | 1998-07-16 | Nokia Telecommunications Oy | Method for establishing a connection in a mobile communication network |
| EP0892569A2 (en) * | 1997-06-26 | 1999-01-20 | Nec Corporation | A method of and a system for assigning a downlink channel for mobile radio communication |
-
1999
- 1999-09-23 CN CNB99122017XA patent/CN1136675C/en not_active IP Right Cessation
- 1999-09-23 AU AU50117/99A patent/AU732013B2/en not_active Ceased
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998031178A1 (en) * | 1996-12-23 | 1998-07-16 | Nokia Telecommunications Oy | Method for establishing a connection in a mobile communication network |
| EP0892569A2 (en) * | 1997-06-26 | 1999-01-20 | Nec Corporation | A method of and a system for assigning a downlink channel for mobile radio communication |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20000020658A (en) | 2000-04-15 |
| CN1136675C (en) | 2004-01-28 |
| CN1250267A (en) | 2000-04-12 |
| AU5011799A (en) | 2000-04-06 |
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| FGA | Letters patent sealed or granted (standard patent) |