CN1136675C - Method for establishing call in honeycomb system - Google Patents

Abstract

A method for establishing a call in a cellular system, comprising: a mobile station requests origination from a base station; a base station requests resource allocation from a mobile switching center; the mobile switching center sends an acknowledgment to the mobile station; the mobile station sends a channel assignment message to the base station; After assigning the message to the mobile station, the base station operates the timer; the base station sends an empty service message to the mobile station; the mobile station sends the mobile station acquisition message to the base station after receiving the message; if the mobile station acquisition message is received before the timer expires, the base station will call The service is connected to the mobile station; if the mobile station acquisition message is not received until the timer expires, the base station resends the channel assignment message to the mobile station.

Description

Method for setting up a call in a cellular system

technical field

The invention relates to a method of setting up a call in a cellular system. More specifically, the present invention is a method for establishing a calling party and a called party in a cellular system using Code Division Multiple Access (CDMA) technology.

Background technique

In a cellular system, the total coverage area is divided into many base station areas, and each base station area has many cell areas as the smallest service area.

A Mobile Switching Center (MSC) controls the base stations and enables calls to continue even when the mobile phone moves between cells.

Figure 1 shows the structure of a cellular system using Code Division Multiple Access (CDMA) technology. As shown, the cellular system includes: base stations (BS) 20, 30, 40 for providing call services to mobile stations (MS) 10; Center (MSC)50.

In the above cellular system, the link from the base station to the mobile station is called the forward link, and the link from the mobile station to the base station is called the reverse link.

A base station supporting CDMA technology uses a number of channels with pilot, synchronization and paging channels, as well as traffic channels for the forward link and access channels for the reverse channel.

The base station uses equipment called channel elements CE for operating channels. And the base station has many channel units, and each channel unit is operated by one of the above channels.

If the user requests a session, the mobile station attempts to establish a call originating at the base station.

Figure 2 is a flow chart illustrating a known method of setting up a call.

The mobile station 10 sends an Origination/Paging Response message to the Base Station Control Processor (BCP) 24 through the Base Station's Access Channel Unit (ACH) 22 (step 1).

The base station control processor sends a message requesting resource allocation to the mobile switching center 50, and sends an origination/paging acknowledgment to the mobile station via the paging channel unit (PCH) 23 (step 3).

The mobile switching center 50 looks up the information of the user requesting material allocation, and sends a channel allocation message to the base station control processor 24 when the user has the service right to receive the call (step 4).

After sending the channel assignment message to the mobile station through the paging channel unit, the base station processor selects one of the above traffic channels usable in the base station and sends the traffic assignment through the selected traffic channel unit (step 4).

The traffic channel unit 21 sends an empty traffic message without call data to the mobile station, and notifies the state of the allocated traffic channel (step 7).

After receiving the empty traffic message, the mobile station sends a preamble to the traffic channel unit in order to inform the state of preparing to call.

The traffic channel unit with the mobile station preamble sends a mobile station acquisition message to the base station control processor (steps 8 and 9).

Then, the mobile station and the base station handle the call by exchanging voice data.

The base station control processor operates a timer having a predetermined operating time (for example, 5 seconds) while transmitting a channel assignment message to the mobile station through the paging channel unit (step 6).

If the propagation state rapidly deteriorates according to the state of the mobile station, the mobile station cannot receive the channel assignment message transmitted using the paging channel element.

Also, since the mobile station cannot switch from the paging channel to the traffic channel, the mobile station cannot receive empty traffic messages for traffic channel elements, and the base station cannot detect signals from the mobile station because the mobile station cannot send preambles to the base station.

After sending the channel allocation message (in step 5), if the mobile station acquisition message is not received until the timer expires normally, the base station control processor ignores all actions performed in the previous steps and sends a release message to the service channel unit to cancel the call (step 10).

However, in the above case, the base station has requested call setup and allocated resources to the mobile switching center or public switched telephone network.

Therefore, resources allocated to base stations, MSCs and PSTN should be removed even when the mobile station is not only receiving channel assignment messages.

As mentioned above, known methods for setting up calls do not use resources efficiently and have the problem of low traffic rates due to call set up failures.

Contents of the invention

The present invention originates from solving the above problems.

It is an object of the present invention to provide a method for setting up a call in a cellular system when a mobile station is not receiving a channel assignment message from a base station due to a bad state of the forward link in attempting to continue the call.

Another object of the present invention is to provide a method for setting up a call in a cellular system by causing a base station to retransmit a channel assignment message when the mobile station has not received the channel assignment message from the base station.

Another object of the present invention is to provide a method for maintaining allocated resources until the mobile station cancels the call to set up a call in a cellular system when the base station sending the channel assignment message does not receive a preamble from the mobile station.

To achieve the above objects, the present invention provides a mobile station with a mobile station for providing call services to users, a base station for exchanging radio messages to the mobile station, and a mobile station for connecting the base station to another base station or to the public switched telephone network. A method for establishing a call in a cellular system of a switching center, the method comprising the steps of: requesting origination from a mobile station to a base station; requesting resource allocation from the mobile switching center by the requested base station; sending an acknowledgment from the mobile switching center using the allocated resources to the mobile station; the base station sends a channel assignment message to the mobile station; the base station operates the timer after sending the channel assignment message to the mobile station; the base station sends an empty traffic message notifying the status of the traffic channel assignment to the mobile station; After receiving the empty service message, the base station sends the mobile station acquisition message to the base station; if the mobile station acquisition message is received before the timer ends normally, the base station will connect the call service to the mobile station; if the mobile station does not receive the call service until the timer ends normally After obtaining the message, the base station resends the channel allocation message to the mobile station.

The present invention also provides a cellular system with a mobile station for providing call services to subscribers, a base station for exchanging radio messages to the mobile station, and a mobile switching center for connecting the base station to another base station or to the public switched telephone network. A method for establishing a call in the system, the method includes the following steps: the mobile station requests origination from the base station; the requested base station sends an acknowledgment to the mobile station; the mobile station operates a timer; if an empty call is received before the timer ends normally If the service message is received, the mobile station will connect the call service to the base station; if no empty service message is received until the timer ends normally, the call will be canceled.

The present invention also provides a cellular system with a mobile station for providing call services to subscribers, a base station for exchanging radio messages to the mobile station, and a mobile switching center for connecting the base station to another base station or to the public switched telephone network. A method for setting up a call in the system, the method includes the following steps: the mobile station requests the base station to set up a call; the requested base station sends a channel assignment message to the mobile station; After receiving the acquisition signal, the base station retransmits the channel allocation message to the mobile station.

The present invention also provides a cellular system with a mobile station for providing call services to subscribers, a base station for exchanging radio messages to the mobile station, and a mobile switching center for connecting the base station to another base station or to the public switched telephone network. A method for establishing a call in the system, the method includes the following steps: the mobile station requests the base station to establish a call; the requested base station requests resource allocation from the mobile switching center; the requested base station sends an acknowledgment to the mobile station; the requested base station sends a confirmation to the mobile station; The mobile switching center assigns channels to the mobile station; the base station sends a channel assignment message to the mobile station; if the base station that sends the channel assignment message does not detect that the mobile station acquires a signal within the first predetermined time, then maintain the relevant connection to the base station and the mobile switching center resources of the mobile station.

Description of drawings

Figure 1 shows the structure of a conventional cellular system utilizing Code Division Multiple Access (CDMA) technology;

Figure 2 is a flow chart representing a known method for setting up a call;

Fig. 3 shows the structure according to the cellular system of the present invention; With

Fig. 4 is a flowchart illustrating a method of setting up a call according to the present invention.

Detailed ways

According to one embodiment of the present invention, there is provided a mobile station for providing call services to subscribers, a base station for exchanging radio messages to the mobile station, and a base station for connecting the base station to another base station or to the public switched telephone network A method for establishing a call in a cellular system of a mobile switching center, the method comprising the following steps:

Request origination from the mobile station to the base station;

requesting resource allocation from the mobile switching center by the requested base station;

sending an acknowledgment from the mobile switching center to the mobile station using the allocated resources;

The mobile station sends a channel allocation message to the base station;

operating the timer after sending a channel assignment message by the base station to the mobile station;

The base station sends an empty traffic message notifying traffic channel allocation status to the mobile station;

sending a mobile station acquisition message to the base station by the mobile station after receiving a null traffic message from the base station;

If the mobile station acquisition message is received before the timer ends normally, the base station connects the call service to the mobile station;

If the mobile station acquisition message is not received until the timer ends normally, the base station resends the channel assignment message to the mobile station.

Preferably, the method further comprises the further step of storing information about the mobile station after operating the timer.

Preferably, the step of retransmitting the channel assignment message is performed after looking up stored information about the mobile station.

According to another embodiment of the present invention, there is provided a mobile station for providing call service to a user, a base station for exchanging radio messages to the mobile station, and a base station for connecting the base station to another base station or a public switched telephone A method for establishing a call in a cellular system of a mobile switching center of a network, the method comprising the following steps:

Request origination from the mobile station to the base station;

An acknowledgment is sent by the requested base station to the mobile station;

the timer is operated by the mobile station;

If an empty traffic message is received before the timer expires normally, the mobile station connects the call traffic to the base station;

If no empty traffic message is received until the timer ends normally, the call is canceled.

According to another embodiment of the present invention, there is provided a mobile station for providing call services to subscribers, a base station for exchanging radio messages to the mobile station, and a base station for connecting the base station to another base station or a public switched telephone A method for establishing a call in a cellular system of a mobile switching center of a network, the method comprising the following steps:

The mobile station requests the base station to establish a call;

sending a channel assignment message to the mobile station by the requested base station;

If the base station that sent the channel assignment message does not receive an acquisition signal from the mobile station within a predetermined time, the base station resends the channel assignment message to the mobile station.

Preferably, the step of sending the channel assignment message includes the following steps:

using information about the mobile station to generate a channel assignment message;

sending the generated channel assignment message to the mobile station;

Information about the mobile station is stored in memory in the base station.

Preferably, the step of resending the channel allocation message includes the following steps:

Find stored information about the mobile station;

Regenerating a channel assignment message using the searched information;

Send the regenerated channel assignment message to the mobile station.

According to another embodiment of the present invention, there is provided a mobile station for providing call service to a user, a base station for exchanging radio messages to the mobile station, and a base station for connecting the base station to another base station or a public switched telephone A method for establishing a call in a cellular system of a mobile switching center of a network, the method comprising the following steps:

The mobile station requests the base station to establish a call;

requesting resource allocation from the mobile switching center by the requested base station;

An acknowledgment is sent by the requested base station to the mobile station;

Allocating the channel to the mobile station by the requested mobile switching center;

The base station sends a channel allocation message to the mobile station;

If the base station which sent the channel assignment message does not detect the mobile station acquisition signal within the first predetermined time, the resources associated with the mobile station connected to the base station and the mobile switching center are maintained.

Preferably, the resources associated with the mobile station are maintained until a second predetermined time has elapsed after the mobile station has received an acknowledgment from the base station.

Preferably, the method further includes another step: if the base station sending the channel assignment message does not detect that the mobile station acquires a signal within the first predetermined time, then resend the channel assignment message to the mobile station.

Preferably, the method further comprises a further step of storing information about the mobile station in a memory in the base station after the base station sends the channel assignment message to the mobile station.

Preferably, the method further includes another step: if the base station sending the channel assignment message does not detect that the mobile station acquires a signal within the first predetermined time, then the base station searches for information about the mobile station.

Preferably, the method further includes another step: after searching the information about the mobile station, resending the channel assignment message to the mobile station by using the found information about the mobile station.

Figure 3 shows the structure of a cellular system according to the invention.

As shown, mobile station 10 is connected to a number of channel elements of base station 20 via radio links.

The base station control processor 24 sends the call data similar to the voice to the mobile station or receives the call data similar to the voice from the mobile station through the traffic channel unit 21, and receives the communication control message of the mobile station through the access channel unit 22, and passes the paging channel Unit 23 sends a communication control message to the mobile station.

If the mobile station receives an acknowledgment of the origination/paging response message for establishing a call sent to the base station, the mobile station 10 operates a second timer having a predetermined operation time (for example, 12 seconds).

The mobile station waits for the channel assignment message from the base station until the second timer ends normally.

If the call is connected until the second timer ends normally, the mobile station cancels the call.

Therefore, the present invention is a method of retransmitting the channel assignment message before the second timer of the mobile station normally ends.

When the base station sends a channel assignment message to the mobile station, the base station stores the same message in memory.

If the mobile station does not receive the channel assignment message from the base station due to a bad state of the forward link, the base station retransmits the stored channel assignment message to the mobile station.

When the base station transmits the channel allocation message, the base station operates the first timer.

If the preamble is not received from the mobile station until the first timer normally ends, the base station retransmits the channel assignment message.

If the state of the mobile station is better, the mobile station receives the channel allocation message and sends a preamble to the base station to connect the call between the base station and the mobile station.

Fig. 4 is a flowchart showing a method of establishing a call according to the present invention.

If the user requests a call, the mobile station 10 sends an origination/paging response message to the base station control processor (BCP) 24 via the access channel unit (ACH), 22 of the base station 20 (step 110).

The base station control processor requests resource allocation from the mobile switching center 50 (step 120), and sends a base station acknowledgment to the mobile station through the paging channel unit (PCH) 23 (step 130).

At this time, the mobile station receives an acknowledgment from the paging channel unit of the base station and operates the second timer.

The mobile switching center 50 that requests to be used for originating resource allocation looks up the information about originating user, and allows channel assignment when originating user has calling service qualification, and base station control processor sends channel assigning message to by paging channel unit Mobile Station (step 140).

But if the radio status of the forward link of the mobile station is degraded, the mobile station cannot transfer to the traffic channel because the mobile station cannot receive the channel assignment message.

Accordingly, the base station control processor sends the channel assignment message to retransmit the channel assignment message (step 140), operates the first timer (step 150) and stores information about the mobile station.

After sending the channel assignment message to the mobile station, the base station control processor selects an available traffic channel element (TCH) and notifies the mobile station that a traffic channel has been assigned by sending a null traffic message through the traffic channel element (step 160).

The mobile station receiving the empty traffic message sends an acknowledgment of the preamble through the traffic channel unit, and the traffic channel unit receiving the preamble sends an acquisition message to the base station control processor.

After the base station control processor receives the acquire message (step 170), the base station connects the call to the mobile station (step 210).

But if the mobile station does not receive the channel assignment message due to bad radio conditions, the mobile station cannot receive the null traffic message and cannot send the traffic channel element as a preamble for the null traffic message acknowledgment to the base station.

If the mobile station acquisition message (step 180) has not been received from the traffic channel unit until the first timer ends normally, the base station control processor searches the stored information about the mobile station, and utilizes the result of the search to generate a channel assignment message (step 180). 190), and retransmit the channel assignment message to the mobile station (step 200).

If the radio status of the mobile station is good, the mobile station receives the retransmitted channel assignment message and moves from the paging channel to the traffic channel.

The base station control processor that retransmits the channel assignment message selects one of the traffic channel elements (TCH) and sends the traffic channel assignment message to the selected traffic channel element.

The traffic channel unit sends empty traffic messages to the mobile station.

Subsequently, the mobile station notifies the state of preparing for a call by sending a preamble to the traffic channel unit, and the traffic channel unit sends a mobile station acquisition message to the base station control processor to connect the call.

The mobile station receiving the acknowledgment (step 130) from the base station operates the second timer, and automatically cancels the call when no empty traffic message is received from the base station until the second timer ends normally, to avoid useless allocation.

Since there is no need to retransmit the channel allocation message when the channel allocation message is lost twice in a row, the base station which sends the second channel allocation message to the mobile station does not re-store the information about the mobile station.

The effects according to the present invention are as follows.

If the mobile station does not receive the channel assignment message due to temporary poor radio status, the base station resends the channel assignment message before the mobile station closes its own timer and cancels the call, so the channels connected to the base station, mobile switching center and public switched telephone network Resources used for call origination are not wasted.

Therefore, the resources between the base station and the mobile station and the resources in the system can be used more effectively, and the service rate can be improved.

Claims (13)

1. One kind have be used for providing the travelling carriage of call business to the user, be used to exchange radio message to the base station of travelling carriage and the cellular system that is used for the base station is linked the mobile switching centre of another base station or public switch telephone network set up the method for calling out, the method may further comprise the steps:

   Start to base station requests by travelling carriage;

   By requested base station to mobile switching centre's requests resource allocation;

   Utilizing the resource of being distributed to send from mobile switching centre confirms to travelling carriage;

   Give travelling carriage by the base station channel assignment message;

   By base station operation timer after channel assignment message is given travelling carriage;

   The empty service message of state that is sent the informing business channel allocation by the base station is to travelling carriage;

   Travelling carriage sends travelling carriage and obtains message to the base station after receiving empty service message from the base station;

   If received that before the timer normal termination travelling carriage obtains message, then links travelling carriage by the base station with call business;

   If do not receive that until the timer normal termination travelling carriage obtains message, then give travelling carriage by base station retransmission channel assignment messages.
2. 2. according to the method for claim 1, also be included in another step of storing relevant mobile station information after the operation timer.
3. 3. according to the process of claim 1 wherein the step of after searching the stored information of relevant travelling carriage, carrying out the retransmission channel assignment messages.
4. One kind have be used for providing the travelling carriage of call business to the user, be used to exchange radio message to the base station of travelling carriage and the cellular system that is used for the base station is linked the mobile switching centre of another base station or public switch telephone network set up the method for calling out, the method may further comprise the steps:

   Start to base station requests by travelling carriage;

   Send affirmation to travelling carriage by requested base station;

   By the travelling carriage operation timer;

   If before the timer normal termination, receive the sky service message, then call business linked the base station by travelling carriage;

   If do not receive the sky service message until the timer normal termination, then cancellation is called out.
5. One kind have be used for providing the travelling carriage of call business to the user, be used to exchange radio message to the base station of travelling carriage and the cellular system that is used for the base station is linked the mobile switching centre of another base station or public switch telephone network set up the method for calling out, the method may further comprise the steps:

   Set up calling by travelling carriage to base station requests;

   Give travelling carriage by requested base station channel assignment message;

   If the base station of channel assignment message does not receive from travelling carriage and obtains signal in the given time, then give travelling carriage by base station retransmission channel assignment messages.
6. 6. according to the method for claim 5, wherein the step of channel assignment message may further comprise the steps:

   Utilize the information of relevant travelling carriage to generate channel assignment message;

   The channel assignment message that transmission is generated is to travelling carriage;

   The information stores of relevant travelling carriage is arrived the memory of base station.
7. 7. according to the method for claim 6, wherein the step of retransmission channel assignment messages may further comprise the steps:

   Search the stored information of relevant travelling carriage;

   Utilize the information of being searched to regenerate channel assignment message;

   The channel massage that transmission regenerates is to travelling carriage.
8. One kind have be used for providing the travelling carriage of call business to the user, be used to exchange radio message to the base station of travelling carriage and the cellular system that is used for the base station is linked the mobile switching centre of another base station or public switch telephone network set up the method for calling out, the method may further comprise the steps:

   Set up calling by travelling carriage to base station requests;

   By the base station of being asked to mobile switching centre's requests resource allocation;

   Send affirmation to travelling carriage by the base station of being asked;

   Give travelling carriage by mobile switching centre's allocated channel of being asked;

   Give travelling carriage by the base station channel assignment message;

   If the base station of channel assignment message does not detect travelling carriage and obtains signal in first scheduled time, then maintain the resource of closing the travelling carriage that is connected to base station and mobile switching centre.
9. 9. method according to Claim 8 wherein keeps the resource of relevant travelling carriage, experiences for second scheduled time until travelling carriage after the confirmation of receipt of base station.
10. 10. method according to Claim 8 also comprises another step: do not obtain signal if the base station of channel assignment message detects travelling carriage in first scheduled time, then the retransmission channel assignment messages is given travelling carriage.
11. 11. method according to Claim 8 also comprises another step: after giving travelling carriage, with the information stores of the relevant travelling carriage memory in the base station by the base station channel assignment message.
12. 12., also comprise another step: do not obtain signal if the base station of channel assignment message detects travelling carriage in first scheduled time, by the information of the relevant travelling carriage of base station lookups according to the method for claim 11.
13. 13., also comprise another step: after searching the information of relevant travelling carriage, utilize the information retransmission channel assignment messages of the relevant travelling carriage of searching to give travelling carriage according to the method for claim 12.

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