MXPA99004316A - Channel resource management within a digital mobile communications network - Google Patents

Abstract

A disconnect time in accordance with the Global System for Mobile (GSM) Phase 1 standard is reduced within a particular base station controller (BSC) serving a particular mobile station (20). In response to a Layer 2 Disconnect message from a first mobile station (20) and after the expiration of the reduced disconnect time, the serving BTS (30) releases the indicated logical channel from the first mobile station (20) and enables the connected base station control (BSC) (40) to more efficiently allocate the released logical channel (SDCCH or TCH) to a second mobile station (25). Thereafter, additional Layer 2 Disconnect messages transmitted by the first mobile station (20) are ignored and no acknowledging Disconnect Mode (DM) message is transmitted over the indicated logical channel. Thus, collision over the same logical channel between the first and second mobile stations (20, 25) is avoided and the second mobile station (25) is able to communicate over the allocated logical channel.

Description

'ADMINISTRATION OF THE RESOURCES OF THE CHANNEL WITHIN A DIGITAL MOBILE COMMUNICATIONS NETWORK " BACKGROUND OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a telecommunications network and, in particular, to the efficient management of channel resources within a digital mobile communications network.

DESCRIPTION OF THE RELATED TECHNIQUE The general name of the connection between the specific mobile station running within a specific cell area and the base station of the transceiver (BTS) provides radio coverage for that specific cell area is the "radio interface" or "air interface".

Historically, the communications of the information through the air interface between a base station of the transceiver (BTS) and a mobile station has employed, the so-called analog modulation techniques. For example, Multiple Access Frequency Division technology (FDMA) has been widely used to assign each mobile station to one of a plurality of channels of - - frequency associated with the current cell area to communicate with the service BTS. More recently, however, digital modulation techniques have been used in order to improve the efficiency of the spectrum with which the bandwidth allocated to mobile communications is used. As an illustration, the two time division multiple access (TDMA) or code division multiple access (CDMA) techniques have been used to allow communications to progress between a BTS and a plurality of different mobile stations in an amount relatively limited radio frequency bandwidth. The communication system, for example, the Global System for Mobile Station (GSM) uses the concept of TDMA with a TDMA frame per carrier frequency channel to communicate between the mobile station and a BTS. A table consists of eight time slots (TS). Each time slot of a TDMA frame on a single frequency channel is referred to as a physical channel. Therefore, there are eight physical channels per carrier in the GSM system. Each physical channel of the GSM system can be compared to a single channel in a FDMA system, where each user is connected to the system through one of the associated frequencies. The use of TDMA technology requires that a large amount and variety of information must be - - transmit between the service BTS and the mobile station through limited physical channels. For example, control data, service request data, current traffic data, supplementary data, etc. they have to be communicated through the physical channels. As a result, in order to distinguish one type of data from another, the different logical channels have been named and projected (assigned) to the available physical channels. For example, the current voice is sent on the logical channel called "traffic channel (TCH)" which occupies one or more physical channels. The radiolocation of a mobile station of the called party is carried out through the "radiolocation channel" In addition, the synchronization of a mobile station with a service BTS is carried out through the logical "synchronization channel (SCH)" which occupies a part of the physical channels, therefore, depending on the type of information that is being transmitted, different logical channels are used, needless to say, that if more physical channels are assigned to a specific logical channel, a smaller number of physical channels are available for the rest of the logical channels. resources of limited physical channels, mobile service providers are often faced with the management of channel resources and sizing problems. to the fact that congestion in the logical channels of SDCCH and / or TCH results in calls that are lost in unsatisfactory call facilities, the efficient management of SDCCH and / or TCH is critical to provide a reliable mobile service to mobile stations that operate within a service coverage area. One of the ways to make better use of channel resources is for the base station of the service transceiver (BTS) to efficiently and effectively release the logical channels that are no longer needed, as an illustration, when a specific mobile station deals with releasing a retained logical channel (eg a TCH and / or SDCCH), a request signal is transmitted by the mobile station giving instructions to the service BTS that the logical channel releases. Upon receiving the request signal, the service BTS transmits a recognition signal back to the requesting mobile station confirming the release. The mobile station then stops communication through the freed channel and the logical channel could be made available to other mobile stations. However, due to radio interference and other ground obstacles, the requesting mobile station sometimes fails to receive the transmitted recognition signal. Not knowing if the first release signal was received - by the service BTS, the mobile station then tries again to release the channel by transmitting another release request signal to the service BTS through the same logical channel. The mobile station repeats the aforementioned re-transmission until the expected acknowledgment signal is received or a designated period of time has elapsed. Within the GSM standard of phase 1, in case no acknowledgment signal is received from the service BTS, the mobile stations are programmed to retransmit a request release signal up to five times with a range of 235 milliseconds As a result, in the worst case, the mobile station repeatedly transmits five disconnect signals through the same logical channel for a total of 1,175 milliseconds (235 X 5) after determining that the channel is no longer needed. Similarly, the service BTS and / or the BSC also has no way of determining whether the transmitted acknowledgment signal has been received by the requesting mobile station. The service BTS therefore also does not know if any of the additional Disconnect signals will be received through the same SDCCH from the requesting mobile station. As a result, even after properly receiving the first release request from the mobile station, the service BTS and the BSC must delay the release of the logical channel for possible re-transmission of the disconnect signals by means of the unrecognized mobile station. during the delay period of 1,175 milliseconds. The delay of 1,175 milliseconds for each and every one of the SDCCH releases and a corresponding time delay for TCH, constitute an inefficient and useless administration of the valuable logical channel resources. Accordingly, there is a need for a mechanism to minimize the delay of channel release within the service BTS.

COMPENDIUM OF THE INVENTION The present invention provides a method and an apparatus for releasing a logical channel within a mobile telecommunications network. A normal IT disconnect synchronizer, as specified by the Global System for Mobile Station (GSM) communications standard, is reduced to a lower value of T2 in the base station controller (BSC) serving a mobile station specific. When that mobile station transmits a GSM-based 2-Layer Disconnect signal to release the held logical channel, the base station of the service transceiver (BTS) recognizes the Disconnect signal by transmitting an acknowledgment signal. Then, the indicated logical channel is released by the service BSC after the synchronizer T2 expires. The released channel is then assigned to another mobile station requesting mobile service within the same coverage area of the BSC. Next, if the mobile station fails to receive the transmitted recognition signal, in accordance with the GSM standard, another 2-layer Disconnect signal is received by the service BTS. In accordance with the teachings of the present invention, the newly received Disconnect signal is ignored and no additional recognition signal is transmitted by the service BTS. In one embodiment, the BTS ignores any subsequent Disconnection signal unless a three-layer signal (3) is first received from the mobile station.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the method and apparatus of the present invention can be obtained by referring to the following detailed description when taken in conjunction with the accompanying drawings, in which: Figure 1 is a functional diagram of a mobile telecommunications network illustrating a mobile station communicating with a base station of the service transceiver (BTS); Figure 2 is a functional diagram of physical channels in accordance with time division multiple access (TDMA) technology; Figure 3 is a functional diagram of the different logical channels within a TDMA physical box in accordance with the global system standard for mobile station (GSM); Figure 4 is a signal sequence diagram illustrating a normal channel release procedure in accordance with the GSM phase 1 standard; Figure 5 is a signal sequence diagram illustrating the collision between two mobile stations if a logical channel is previously released by the service BTS of the requesting mobile station; and Figure 6 is a signal sequence diagram illustrating the service BTS ignoring subsequent Disconnect signals in accordance with the teachings of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS - - Figure 1 is a functional diagram of a Land Mobile Public Network 10 (PLMN) illustrating a mobile station 20 communicating with a base station 30 of the service transceiver (BTS). A geographic area associated with a specific Land Mobile Public Network 10 (PLMN) is divided into a number of smaller areas. When a mobile station 20 marches to one of those smaller areas known as a "location area", a base station controller (BSC) 40 serving that specific location area detects the stations mobile mobiles and informs the mobile switching center / associated visitor location register (MSC / VLR) 50 of the presence of the mobile station. In case the mobile station 20 is a non-registered subscriber, a home location register (HLR) 60 associated with the newly registered mobile station 20 is identified and the necessary communication between the service MSC / VLR 50 and the HLR 60 to authenticate the new mobile station 20. The required subscriber information related to the newly registered mobile station 20 is further requested and retrieved from the associated HLR 60 and stored in the service MSC / VLR 50. Then, the mobile station 20 is allowed to access the mobile service within the coverage area of the service MSC / VLR 50. 1 When an incoming call connection is requested to the mobile station 20, a call installation signal is received, such as an Initial Address Message (IAM) based on the User Part of the Integrated Service Digital Network (ISUP). by an Access Gateway mobile switching center 80 (GMSC) associated with the HLR 60. After carrying out the HLR interrogation to ensure the current location of the mobile station 20, the incoming call installation signal received it is again routed via the GMSC 80 to the MSC / VLR 50 which currently serves the mobile station 20. The MSC / VLR 50 then determines the current location area of the mobile station 20 and instructs the appropriate base station controller (BSC) 40 to radio locate the mobile station 20. The BTS 30 then self-locates the mobile station through a self-localization channel (PCH) to alert the mobile station of an incoming call. As soon as the mobile station detects the self-location message, the mobile station 20 is sent to a request for a signal sending channel through a Random Access Channel (RACH) to the BSC 40. After assigning a Control Channel Dedicated Located Solo (SDCCH) to the mobile station 20, the BSC 40 sends a message instructing the mobile station 20 to switch to the specific SDCCH. After communicating the data related to the service and the necessary control through the newly assigned SDCCH channel, a traffic channel (TCH) and a call connection between the mobile station 20 and the BSC 40 is subsequently set up via of the BTS 30. Initially, the communication interface 90 between the service BTS 30 and the mobile station 20 used the so-called analog modulation techniques. However, with recent developments in digital communication technology, digital modulation techniques are being used to improve the efficiency and capacity of data communications within a mobile telecommunications network. As an illustration, time division multiple access (TDMA) or code division multiple access (CDMA) techniques are being used to allow multiple communications to advance in a relatively limited amount of radio frequencies. Telecommunications networks based on the Global System for Mobile Station (GSM), for example, use TDMA technology, with a TDMA frame per carrier frequency to communicate between a mobile station and a BTS. Reference is now made to Figure 2 which illustrates a diagrammatic representation of time frame structures within a GSM standard. The term - - The most recurrent time of the structure is called a hyperframe 100 and lasts 3 hours, 28 minutes, 53 seconds, 760 milliseconds. A hyperframe 100 is divided into 2,048 superframes 105, each having a duration of 6.12 seconds. The superframe 105 in case it is subdivided into a number of multiple frames. The two types of multiple frames exist in the GSM standard. First there is a 110 multi-frame of fifty-one (51) frames with a duration of 120 milliseconds comprising twenty (26) frames TDMA 130. Then, there is a multicuad 120 of twenty-six (26) frames with a duration of 235.4 milliseconds comprising fifty-one (51) frames 140 of TDMA. Finally, each TDMA frame within a multi-frame has eight time slots 150. Each of these eight physical time slots is equivalent to a Multi-Division Frequency Division (TDMA) channel serving a single mobile station . A large amount of variety of information must be transferred between the BTS and the mobile station. For example, radiolocation to inform the mobile station of an incoming call has to be carried out through one of the time slots. An application for mobile service also needs to be communicated through one of the time intervals. In addition, the data - - of real voice must communicate through the available time intervals. Therefore, in order to distinguish one type of information from another, different logical channels have been introduced that have been assigned to each of the eight physical time intervals. Reference is now made to Figure 3 which illustrates different logical channels within the GSM standard that can be separated into two broad categories: traffic channels (TCH) 160 and signal sending channels 170. Traffic channels (TCH) 169 are used by the service BSC to communicate the call data (e.g., the voice data) with a specific mobile station running within its coverage area. On the other hand, the signal sending channels 170 are used by the service BSC and the BTS to communicate other control data necessary to implement the communication of the call data with the mobile station. The signal sending channels are further subdivided into three categories: broadcast control channels 270, common control channels 280 and dedicated control channels 280. Each of the three aforementioned categories are further subdivided into a number of logical channels for transporting the different types of information between the service BTS and the mobile station.

- The broadcast control channels 270 are mainly used to communicate the information from the service BTS to a specific mobile station running within its coverage area (downlink) include the Frequency Correction Channel (FCCH) 180, the Synchronization Channel (SCH) 190, and Broadcast Control Channel (BCCH) 200. Frequency Correction Channel (FCCH) 180 carries the information for frequency correction of the mobile station. The Synchronization Channel (SCH) 190 carries the information for synchronization of the frame of the mobile station and identification of the BTS. Finally, the Broadcast Control Channel (BCCH) 200 is used to broadcast the general system information about the cell to all mobile stations placed within its location area. For example, the broadcast system information includes data about the network where the mobile station needs to be able to communicate with the network in an appropriate manner. This information includes the description of the cell, the identity of the location area, the description of the neighboring cell, etc. Common control channels 280 include the Radiolocation Channel (PCH) 210, the Random Access Channel (RACH) 220 and the Access Grant Channel (AGCH) 230. The Radiolocation Channel (PCH) 210 is used - - in the downlink to radiolocate a mobile station. For example, when an incoming call installation request is received by the service MSC / VLR, the appropriate BSC currently serving the mobile station receives instructions to radiolocate the specified mobile station through a PCH. The Random Access Channel (RACH) 220, on the other hand, is used by the mobile station to request the allocation of a Dedicated Located Solo Control Channel (SDCCH) 240 to the BSC. For example, upon detecting the radiolocation message that the mobile station reports from an incoming call, the mobile station of the called party requests an SDCCH from the service BSC through the RACH. After assigning an empty SDCCH, the BSC uses an Access Grant Channel (AGCH) 230 to communicate the identity of the SDCCH assigned to the requesting mobile station. The dedicated control channels 290 include a Located Solo Dedicated Control Channel (SDCCH) 240, a Slow Associated Control Channel (SACCH) 250, and the Quick Associated Control Channel (FACCH) 260). The Solo Located Dedicated Control Channel (SDCCH) 240 is used to send signals with a dedicated mobile station. Accordingly, the SDCCH 240 is the channel used to carry out the location update procedures when a - - mobile station enters a new location area. The SDCCH is also used to initiate a call setup and to retain a TCH. The Slow Associated Control Channel (SACCH) 250 is associated with a TCH 160 or an SDCCH 240. The SACCH 250 is a continuous data channel that carries the continuous control information, such as measurement reports, the order of progress of synchronization and power, between the service BSC and the mobile station. Finally, the Fast Associated Control Channel (FACCH) 260 is associated with a specific TCH to work in a burst mode to replace the speech or data traffic with other necessary signals. As illustrated above, with nine different types of logical signaling channels and one logical traffic channel occupying limited physical channels, the eight time slots within a TDMA frame need to be managed efficiently and effectively. to provide a reliable mobile service to mobile stations that march within a specific BSC coverage area. Since the assignments of the logical channel to the physical channels can not change dynamically since the demands for each logical channel change within the service network, it is crucial to determine the appropriate number of physical time slots to be assigned to each of them. the - - logical channels. Especially, since congestion in two of the most frequently used logical channels (SDCCH and TCH) results in a call connection that has failed, and loss of calls. Even after assigning an appropriate number of physical channels to each logical channel, efficient management of channel resources is also necessary to maximize the potential utilization of the available logical channels. Figure 4 is a signal sequence diagram illustrating a normal channel release procedure in accordance with the GSM Phase 1 standard. When a mobile station 20 marches to a new location area, the mobile mobile station 20 performs a location update to report the current location of the mobile station 20 to the serving MSC / VLR 50 and the associated HLR (not shown in Figure 4). The mobile station (MS) 20 initiates the location update process by transmitting a channel request message 300 to the service BTS through a Random Access Channel (RACH). The service BTS 30 then transmits a Channel Required message 310 to the connected BSC 40. If the SDCCH is available, the BSC 40 transmits a Channel Activation message 320 back to the service BTS 30. The BTS 30 then recognizes the channel activation by returning a message 330 of Recognition of - Activation of Channel to the connected BSC 40. The BSC 40 then transmits an Immediate Assignment Command message 340 to the service BTS 30 instructing the BTS 30 to allocate the assigned SDCCH to the requesting mobile station 20. The service BTS 30 then transmits an Immediate Assignment message 350 to the requesting mobile station 20 instructing the mobile station 20 to count to the allocated SDCCH. After receiving the Immediate Assignment message 350, the mobile station 20 is switched to the ordered SDCCH and establishes a main signal sending link by sending a message 360 of Adjusted Asynchronous Balanced Mode (SABM) back to the service BTS 30. The transmitted SABM message 360 includes a "Location Update Request" message and requests that the service MSC / VLR 50 perform a location update. The "Location Update Request" message transmitted through the assigned SDCCH contains, for example, the type of location update, the sequence number of the key or encryption key, the identity of the old location area stored in the location. mobile station, the type of mobile station and the identity of the mobile subscriber. When the transmitted SABM message is received by the service BTS 30, the Location Update Request is sent back to the mobile station 20 in an Unnumbered Recognition (UA) box 370. The service BTS then transmits an Established Indication Message 380 including the "Location Update Request" to the connected BSC 40. The Set Indication Message 380 informs the connected BSC 40 that a communication has been established and a location update procedure has been initiated by the mobile station 20. The BSC 40 then establishes a Signaling and Control Part Connection (SCCP) to the service MSC / VLR 50 by sending a SCCP-based Connection Request message 390 with the "Location Update Request" included in the field of information. This "Location Update Request" message is modified to some degree, since the BSC adds the identity of the new location area indicating that the mobile station 20 is currently located. The modified message is called "complete Layer 3 information" or "Initial MS" message. The service MSC / VLR 50 then recognizes the message by sending a Confirmed Connection (CC) box 400 back to the BSC 40. If the MSC / VLR 50 accepts the location update from the mobile station 20, the MSC / VLR 50 sends a Message 410 Accepted from Location Update to mobile station 20. Accordingly, the Accepted Location Update message (Loe Upd Acc) is also communicated from the BSC 40 connected to the service BTS using a - - Table 420 of Data Request (DR). The service BTS 30 then transmits an Accepted Location Update message 430 through the allocated SDCCH to the mobile station 20. During the update of the successful location of the mobile station 20, the network initiates the channel release by sending a Clear Command (CC) message 400 to the BSC 40. The BSC 40 then sends the Channel Release message transparently through the BTS 30 of service to the mobile station 20 (signals 420 and 430). The BSC 40 then sends a message 470 of Deactivating the SACCH to the BTS 30 instructing the base station to stop sending messages through the Slow Associated Control Channel (SACCH). When the mobile station 20 receives the channel release message 460, the mobile station 20 sends a 2-layer Disconnect message 470 to the BTS to release the held SDCCH. The Disconnect message 470 is recognized by the service BTS 30 again to the mobile disconnection station 20 with the UA box 480. The service BTS 30 further transmits a Release Indication message 530 to inform the connected BSC 40 of the request message to disconnect received. After receiving the 480 frame of UA transmitted by the mobile station 20, the mobile station 20 stops communicating through the identified SDCCH.

Due to radio interference and other ground impediments, sometimes the transmitted UA frame 480 which recognizes the receipt of the Disconnect message 470 is not received by the mobile disconnection station 20. The mobile station 20 then has no way to determine whether the service BTS has properly received the transmitted Disconnect message 470. As a result, in order to ensure that the retained logical channel has been properly released, the GSM Phase 1 standard instructs the mobile station 20 to repeatedly re-transmit the Disconnect message 470 every 235 milliseconds up to 5 times, or until the UA acknowledgment message is received. As an illustration, the mobile station 20 transmits a first Disconnect message 470 to the service BTS 30. The service BTS 30 appropriately receives the Disconnect message 470 and recognizes the same by transmitting a message 480 of UA back to the mobile station 20. In addition, the service BTS 30 transmits a release request signal, such as a Release indication (Ind Network) 530 to inform the connected BSC 40 that the received Disconnect message 470. If the mobile station fails to receive the UA message 480 transmitted after 235 milliseconds, the mobile station re-transmits another Disconnect message 490 to the service BTS. By way of - - similar to the failure of the UA message delivery to the mobile station 20, the disconnection signals transmitted by the mobile station 20 may also stop arriving at the service BTS 30. However, if the Disconnect signal is received by the service BTS 30, the BTS 30 again recognizes it by transmitting a second message 500 of UA. These sequences can be repeated five times before the indicated SDCCH is finally released by the mobile station. The service BSC 40 is associated with the T0 710 synchronizer. After receiving the Release Indication signal 530 (Rei Ind) from the service BTS 30, the BSC 40 waits until the synchronizer T0 expires before giving instructions to the BTS 30 to release the indicated logical channel. In accordance with the GSM specification, the T0 number 710 synchronizer associated with the SDCCH logical channel is also set to 1175 milliseconds. This is because the serving BSC 40 and / or the BTS 30 has no means to determine whether the transmitted UA message 480 has been received by the mobile station 20 and has to wait for potential Disconnect messages. Accordingly, only after the expiration of 1175 milliseconds after receiving the first Disconnect message 470, the serving BSC sends a channel release message, such as the Radio Frequency Channel (RF) Release signal 700, for instruct BTS 30 to release the specified logical channel. It should be understood that the disconnection procedures illustrated above using the SDCCH are for exemplary purposes only and that the disconnection procedure for releasing a TCH is also applicable in the sense that the service BSC also needs to wait for a period of time. corresponding time before actually releasing the TCH. This inefficient and useless delay to free up valuable channel resources is highly undesirable. However, without modifying all existing mobile stations to operate differently from the aforementioned disconnection procedure, at present there is no mechanism to more efficiently release the SDCCHs and / or the TCHs. The requirement that each of the mobile GSM stations of phase 1 be physically modified to work differently is an impractical solution. On the other hand, modifying the service BSC to release the logical channel prior to the associated mobile station also creates undesirable crash problems. Reference is now made to Figure 5 which illustrates the collision of two mobile stations while trying to communicate simultaneously through it - - SDCCH. If the GSM mobile stations of phase 1 are left unchanged to re-transmit the Disconnect signals as illustrated above while the serving BSC 40 releases the indicated SDCCH or TCH without waiting for the full expiration time of 1175 milliseconds, the following shock illustrated through the same SDCCH may occur. A first mobile station 20 currently associated with a specific SDCCH transmits a Disconnect message 470 to the service BTS 30 to release the logical channel. The first mobile station 20 is associated with a synchronizer T0 635 (1175 milliseconds) instructing the mobile station 20 to repeatedly transmit a Disconnect signal every 235 milliseconds until the synchronizer T0 expires or a recognition signal has been received from the Service BTS. On the other hand, a corresponding TI synchronizer 630 within the service BSC 40 has been reduced to a value smaller than the synchronizer T0 number 635. Accordingly, the BSC 40 sends the RF Channel Release message 700 to the BTS 30 connected to prior to what has been indicated by the GSM phase 1 standard. Because the reduced TI synchronizer 630 has also expired, and the RF channel Release message 700 has already been received by the BTS 30, the BTS 30 considers the logical channel specified as having been released and, therefore, being free or unoccupied. Subsequently, a second mobile station 25 requests the mobile service by transmitting a Channel Request 300 to the service BTS 30. The service BTS 30 informs the BSC 40, which in turn, is now able to assign the SDCCH that has just been released by the first mobile station 20 to the second requesting mobile station 25. An Immediate Assignment message 350 is transmitted from the service BTS to the second mobile station 25, instructing the second mobile station 25 to communicate through the specific SDCCH. Consequently, specific SDCCH is retained by the second mobile station 25. However, the UA message 480 transmitted by the service BTS 30 that recognizes the disconnect request stops arriving at the first mobile station 20. Since the associated synchronizer T0 635 has not expired, the first mobile station 20 transmits another disconnect signal 470 to the service BTS 30 through the same SDCCH. Because the transmitted Disconnect signal 470 is a signal from layer 2, the service BTS 30 has no way to determine that the first mobile station is transmitting the unwanted Disconnect signal while the same SDCCH has already been assigned to the second mobile station. In accordance with the GSM standard, the service BTS 30 then transmits a Disconnect Mode Message (Dm) 640 through the SDCCH instructing the mobile station (s) to discontinue the use of the associated SDCCH. The first and second mobile stations that both are tuned to the same SDCCH, receive the 640 signal of Dm and release the channel. As a result, a call installation connection that is being established by the second mobile station 25 is also interrupted and the indicated SDCCH is released by both mobile stations. Figure 6 is a signal sequence diagram illustrating service BTS 30 ignoring subsequent Disconnect signals received through an SDCCH logical channel that has already been assigned to another mobile station. In accordance with the teachings of the present invention, the TI synchronizer number 630 associated with the service BSC 40 is reduced to a value less than that of the synchronizer T0 number 635 associated with the first mobile disconnection station 20. One way to reduce the value of the Ti synchronizer number 630 is to reduce the value in the 235 millisecond interval. Accordingly, the TI synchronizer number 630 can be decreased from 1175 milliseconds as instructed by the GSM standard, to any of 940 milliseconds, 750 milliseconds, 470 milliseconds, 235 milliseconds or 0 milliseconds. Since the synchronizer change T0 - number 635 associated with each mobile GSM station of phase 1 is impractical, the value of the TO synchronizer of 1175 milliseconds remains unchanged. The first mobile station 20 transmits a Layer 2 Disconnect signal 470 to the service BTS 30 through a designated logical channel, such as SDCCH or TCH, to inform the service BTS 30 that the first mobile station 20 no longer you need the designated channel. The service BTS 30 returns a UA message 480 recognizing the receipt of the disconnection message 470. In a conventional manner, the service BTS 30 also informs the connected BSC 40 of the disconnection message 470 received through the message 530 of Rei Ind. After the IT synchronizer number 630 associated with the service BSC 40 expires, the BSC 40 service transmits an RF Channel Release message 700 to the connected BTS 30. The transmitted RF Channel Release message 530 informs the connected BTS that the indicated logical channel, such as SDCCH or TCH is released and is now available to others. Then, the second mobile station 25 requests a logical channel, such as SDCCH for an outgoing call setup, by transmitting a Channel Request message 300 to the service BTS 30. The service BTS 30 then communicates with the connected BSC 40 and is assigned to the same logical channel that was just released from the first mobile station 20. As a result, an Immediate Assignment message 350 is returned to the second mobile station 25 by instructing the second mobile station to start transmitting through the newly assigned logical channel (i.e., SDCCH or TCH). Meanwhile, the UA message 480 which recognizes the receipt of the disconnection message 470 stops arriving at the first mobile station 20, and in response, the first mobile station 20 again tries to release the same logical channel by transmitting a second signal 490 Disconnection to the BTS 30 service. If the TI synchronizer has not yet expired, then the service BTS 30 has not yet received the RF Channel Release message and the subsequently received Disconnect message is handled in a conventional manner. On the other hand, if the TI synchronizer has already expired, the service BTS 30 has already received the RF Channel Release message 700 and has also released the indicated logical channel as fully described above. Therefore, by transmitting a Layer 2 Disconnect message through the same logical channel that is currently occupied by the second mobile station, a signal sending shock occurs in a single physical time interval. As described in Figure 5, the recognition of this - Disconnection message results in the release of the second mobile station and its associated call connection. However, in accordance with the GSM standard, mobile stations are not allowed to transmit the Disconnect message from Layer 2 without first communicating a Layer 3 message with the service BTS. Therefore, by determining that no Layer 3 message has been communicated to release the associated channel between the service BTS 30 and the second mobile station 25, in accordance with the teachings of the present invention, the service BTS ignores the second Disconnection message 490 received from the first mobile station 20. Then, a SABM message of Layer 3 requesting the mobile service (e.g., outgoing call connection) is transmitted from the second mobile station 25 to the service BTS. A UA recognition message 610 is then returned to the second mobile station 25. A service request message 620 is also transmitted to the connected BSC 40 to provide the requested mobile service to the second mobile station 25. In order to maximize the use of the SDCCH and / or TCH logical channels within the service BSC, the TI synchronizer number 630 can be set to 0 millisecond. Correspondingly, after receiving the first Disconnect message from the first mobile station, for example, the service BSC 40 immediately - - Releases the indicated channel without any delay. If the acknowledgment UA message stops arriving at the first mobile station, four additional disconnect messages will be transmitted by the first mobile station and will be ignored by the service BTS 30. Instead, if the TI synchronizer number 630 is set to 235 milliseconds, it will allow the service BTS 30 to recognize an additional Disconnect message in case of the first UA message. stop reaching the first mobile station 20. Therefore, only three additional Disconnect messages can be ignored by the service BTS 30. As another illustration, the TI synchronizer number 630 can be set to 940 milliseconds. After receiving the first Disconnect message, the service BTS 30 does not immediately release the channel, but allows three additional disconnection messages to be received and processed in a conventional manner in case all the corresponding UA messages stop arriving. to the first mobile station 20. Only the fifth disconnect message will be ignored by the service BTS 30. The value assigned to the TI synchronizer number 230 is decided by the BSC operator to provide an effective channel release procedure, while providing the administration of efficient channel resources for the mobile telecommunications network.

- - Accordingly, by ignoring any subsequent Disconnect message received through the freed and re-assigned logical channel, the service BTS and the service BSC can efficiently manage and utilize the valuable channel resources. Although illustrated in the accompanying Drawings, a preferred embodiment of the method and apparatus of the present invention and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiment disclosed, but it is capable of numerous rearrangements, modifications and substitutions, without deviating from the spirit of the invention, as indicated and defined by the following claims.

Claims (30)

1. R E I V I N D I C A C I O N E S: 1. A method for optimizing the use of a logical channel within a digital mobile telecommunication network that includes a transceiver base station (BTS) and a base station controller (BSC) for communicating with a specific mobile station to Through the logical channel and the BSC further includes a disconnect synchronizer with an IT value to delay the release of the logical channel after receiving an indication to release the logical channel from the mobile station, the method comprises the steps of: setting and disconnecting the synchronizer with a value of T2, where the value of T2 is less than the value of TI; receiving a first indication in the BSC to release a currently associated logical channel with a specific mobile station from the mobile station; initiate a downward count in the BSC of the disconnect synchronizer in response to the first indication; release the logical channel after the expiration of the disconnect synchronizer and allow the other mobile stations to use the freed logical channel; Y - - ignore in the BTS, in response to the release of the logical channel, any subsequent indication to release the logical channel from the mobile station.
2. 2. The method of claim 1, wherein the logical channel comprises a Dedicated Control Channel Located Solo (SDCCH).
3. 3. The method of claim 1, wherein the logical channel comprises a Traffic Channel (TCH). The method of claim 1, wherein the TI value is 1175 milliseconds, and wherein the value of T2 is selected from a group of values, each of which is less than 1175 milliseconds and different from one of the another by increments of 235 milliseconds. The method of claim 1, wherein the step of initiating the downcount of the disconnect synchronizer further comprises the step of transmitting an acknowledgment message recognizing receipt of the first indication by the service BTS. The method of claim 5, wherein the mobile station transmits an additional indication of disconnecting the logical channel if the acknowledgment message is not received from the BTS. The method of claim 1, wherein the first indication comprises a Disconnection message - - layer 2 based on Global System communications for the Mobile Station (GSM). The method of claim 1, wherein the step to ignore any subsequent indication to release the logical channel further comprises the step of ignoring the subsequent indication if a Layer 3 message has not been received first through the aforementioned logical channel. . 9. A method for releasing a logical channel associated with a specific mobile station within a mobile telecommunications network, the mobile station being assigned to a TI synchronizer to instruct the mobile station to repeatedly transmit a request to release the mobile channel until that the TI synchronizer expires or until an acknowledgment message is received from the base station of the transceiver (BTS) serving the mobile station, the BTS is also associated with a base station controller (BSC) with a synchronizer T2 for releasing the logical channel, the synchronization value T2 being less than the value of the TI synchronizer, and the method comprising the steps of: receiving a request in the BTS to release the logical channel from the mobile station; inform the BSC of the request received through the BTS; start the countdown of the synchronizer T2 in the BSC; instructing the BTS through the BSC to release the logical channel after the expiration of the synchronizer T2 and to allow the other mobile stations to use the freed channel; and ignore in the BTS a subsequent request to release the logical channel. The method of claim 9, wherein the step of ignoring the subsequent request further comprises the step of ignoring the subsequent request to release the logical channel unless a message of the layer has first been received through the logical channel. 3 based on the Global System for Mobile Station (GSM) communications. 11. The method of claim 10, wherein the message of layer 3 comprises a message of Adjusted Asynchronous Balanced Mode (SABM). The method of claim 9, wherein the logical channel comprises a Traffic Channel (TCH). The method of claim 9, wherein the logical channel comprises a Dedicated Located Control Channel Solo (SDCCH). - - 14. The method of claim 9, wherein the first request comprises a Disconnect signal from layer 2 based on GSM. 15. A system for releasing a logical channel allocated to a mobile station within a mobile communication network, and wherein in order to release the logical channel, the mobile station continues to transmit a request to release the logical channel for a period of time which has an IT duration if an acknowledgment signal is not received from the mobile telecommunications network, comprising: a receiver to receive a request from the mobile station to release the logical channel; a synchronizer for waiting a period of duration of T2 in response to the receipt of the request, wherein the value of period T2 is less than the value of the associated period TI, with the mobile station; a first module associated with the synchronizer for releasing the logical channel associated with the mobile station after the expiration of the synchronizer; and a second module for ignoring any subsequent request to release the logical channel received by the receiver after releasing the logical channel. The system of claim 15, wherein the second module further comprises means for ignoring the subsequent request to release the logical channel unless the receiver first receives a layer 3 message based on the Global Station System communications. Mobile (GSM) through the logical channel. 17. The system of claim 15, wherein the first and second modules are equal. 18. The system of claim 15, wherein the logical channel comprises a Traffic Channel (TCH). The system of claim 15, wherein the logical channel comprises a Dedicated Control Channel Located Solo (SDCCH). The system of claim 15, wherein the first request comprises a Disconnect signal from layer 2 based on Global System communications for Mobile (GSM) station. The system of claim 15, wherein the receiver comprises a base station of the transmitter (BTS) that serves the mobile station. 22. The system of claim 15, further comprising a base station controller (BSC), the BSC being associated with the synchronizer to release the logical channel. 23. A system for optimizing the use of a logical channel within a digital mobile telecommunications network that includes a station - - base of the transceiver (BTS) and a base station controller (BSC) to communicate with a specific mobile station through the logical channel and the BSC includes a first disconnect synchronizer with an IT value to delay the release of the logical channel after receiving an indication to release the logical channel from the mobile station, the mobile station being associated with a second disconnect synchronizer with a value of t2 to specify the duration in order to repeatedly transmit a request to release the logical channel in case an acknowledgment from the BTS is not received, the TI value being related to be less than the value of T2, comprising: a means for receiving the first indication in the BTS to release a currently associated logical channel with a mobile station specific from the mobile station; means for releasing the logical channel after the expiration of the first disconnect synchronizer after receiving the first indication and allowing the other mobile stations to use the logical channel; and a means for ignoring any subsequent indication to release the logical channel from the mobile station. - 24. The system in claim 23, wherein the logical channel comprises a Dedicated Located Control Channel Solo (SDCCH). 25. The system of claim 23, wherein the logical channel comprises a Traffic Channel (TCH). 26. The system of claim 23, wherein the value of T2 is 1175 milliseconds, and where the IT value is selected from a group of values, each of which is less than 1175 milliseconds and different from the other by increments of 235 milliseconds. The system of claim 23, wherein the means for ignoring any subsequent indication to release the logical channel further comprises a means for ignoring any subsequent indication unless a layer 3 message is first received through the logical channel. . 28. A method for releasing a logical channel allocated to a specific mobile station within a mobile telecommunications network, the method comprising the steps of: receiving indication of releasing a logical channel associated with a specific mobile station by a base station of the transceiver (BTS) that serves the mobile station; informing a base station controller (BSC) associated with the BTS of the received indication; receiving in the BTS an instruction from the BSC to release the logical channel associated with the mobile station; and in response to that instruction, ignore in the BTS any subsequent indication of releasing the logical channel received from the mobile station. 29. The method of claim 28, wherein the step of ignoring the indication. Subsequent further comprises the step of ignoring the subsequent indication to release the logical channel unless the layer 3 message based on the Global System for Mobile Station (GSM) communications has first been received through the logical channel. 30. The method of claim 29, wherein the layer 3 message comprises an adjusted Asynchronous Balancing Mode (SABM) message.