MXPA98009056A - Soft transfer inter-systems supporting inter-siste calls - Google Patents

Abstract

A novel and improved method and apparatus for effecting a smooth inter-system transfer is described. In accordance with the present invention, when a subscriber unit crosses from a first cellular system to a second cellular system, a base station controller (20) determines whether sufficient network resources are available to drive smooth inter-system transfer. If so, the controller (20) of the base station generates a set of signaling messages which causes a call processing resource to be allocated and the call to be processed in the second cellular system. The controller (20) of the base station then performs the data selection and the broadcasting of the call data by transmitting the data to the subscriber unit (28) by means of the second cellular system, as well as by means of one or more base stations with which is directly coupled to the base station controller (20). The determination of whether there are sufficient network resources available to conduct smooth inter-system transfer is based on the type of connection that exists between the first cellular system and the second cellular system, the number of inter-system calls that will be driven and the frame shift of the call that is currently processed

Description

SOFT TRANSFER ÍNTER-SISTEMAS THAT SUPPORTS CALLS ÍNTER-SISTEMAS FIELD OF THE. INVENTION The present invention relates to wireless telecommunications. More particularly, the present invention relates to a novel and improved method and apparatus for conducting telephone calls or other communications between wireless telecommunications systems that support smooth intersystem transfers.

BACKGROUND OF THE INVENTION Figure 1 is a diagram of a cellular telephone system configured in accordance with the use of code division multiple access radiofrequency (RF) signal processing (CDMA) techniques. To conduct a telephone call or other communication, a subscriber unit 18 is interconnected with one or more base stations 12 using radiofrequency signals with CDMA modulation in which both traffic and signaling data are exchanged. Each interface includes an uplink traffic channel transmitted within an uplink RF signal from the base station 12 and a link traffic channel P1713 / 98MX descending transmitted within a downlink RF signal from the subscriber unit 18. Using the exchanged data, a subscriber unit 18 communicates with various other types of systems by means of the base station controllers (BSC) including to the public switched telephone network (PSTN) 19 and any systems coupled to it. Typically, BSCs 10 are coupled to PSTN 19 and to base stations 12 via wireline links including, for example, TI or El links, whose use is well known in the art. The IS-95 standard of the air CDMA interface (standard IS-95) promulgated by the Telecommunications Industry 'Association (TÍA) is a set of standards for providing wireless telephone service using RF signals with CDMA modulation. In accordance with the IS-95 standard, uplink and downlink traffic channels are created by direct sequence modulation of the data that will be transmitted with the uplink and downlink traffic channel codes known to both the unit of subscriber 18 as per the base station 12. Additionally, each base station 12 transmits a pilot channel by periodically modulating pilot data with a predetermined pilot channel code, wherein the period associated with the pilot channel P1713 / 98MX generated by each base station 12 which will be set opposite in one of five hundred twelve (512) time shifts to allow the identification of each base station 12. A subscriber unit 18 can detect the presence of the base station 12 when looking for the pilot channel associated. The use of channel codes to form channels allows multiple communications to be conducted within a single RF bandwidth and also allows adjacent base stations 12 to conduct communications using the same RF bandwidth. These two features allow the most efficient use of the available RF bandwidth, which is one of the advantages of CDMA technology. The IS-95 standard also requires that the data be transmitted between the base stations 12 and the subscriber unit 18 in frames of 20 milliseconds (ms). To facilitate the uniform distribution of all data that will be transmitted, the transmission time of each frame is set to one of sixteen frame shifts that occur at some multiple of 1.25 ms after the edge or boundary of the frame. Frame shift is the amount of time that the subscriber unit delays the transmission of a frame after the edge or frame boundary. The frame edge synchrony is supplied to each subscriber unit 18 by information from P1713 / 98MX synchronization transmitted to each subscriber unit 18, using a synchronization channel transmitted within the uplink signal and the frame shift for a particular communication, is determined at the start or beginning of each communication which will remain the same throughout the call. In accordance with the IS-95 standard, the data is transmitted to a four-speed during each 20ms frame, where the four speeds will be referred to as full speed, half speed, one quarter speed and one eighth speed. Cellular networks are known to operate at full speeds of either 9.6 kilo-bits per second or 14.4 kilo-bits per second and the lower speeds for each configuration will be approximately equal to the next higher speed divided by a factor of two. The four speeds associated with a full speed of 9.6 kilo-bits per second are referred to as Speed Set One and the four data speeds associated with a full speed of 14.4 kilo-bits per second are referred to as Speed Set Two. To facilitate the understanding of the exemplary embodiment of the invention described below, the number of bits transmitted at each frame rate for Speed Set One and Set Two Speed are shown in Tables I and II, P1713 / 98MX respectively, together with their probability of associated transmission during a typical voice conversation, however, no particular speed set is necessary to practice the invention, although the sets of speeds described are preferred, because they comply with known standards .

Type of Table Length of the Table Probability (Bits) Full Speed 256 0.291 Medium Speed 160 0.029 One Quarter Speed 120 0.072 One Eighth Speed 96 0.598 Table I 9.6 Kbps frame set Type of Table Length of the Table Probability (Bits) Full Speed 352 0.291 Medium Speed 208 0.029 One Quarter Speed 136 0.072 One Eighth Speed 104 0.598 I-1713 / 98MX Table II. Set of frames at a speed of 14.4 Kbps Referring still to Figure 1, sections of three CDMA cellular systems (which are also referred to as CDMA Cellular Land Networks -CCLN), each of which is comprised of BSC 10 and the set of base stations 12 to which is coupled. The base station 12 is interconnected with a set of subscriber units 18 located within the corresponding coverage area 15. Most of the coverage areas 15 are divided into sectors 17 that correspond to the separate antenna and processing systems. RF signal within each base station 12 that are normally configured in a specific address form. The coverage area 15A is shown as a single sector 20 which generally corresponds to one or more systems of omnidirectional antennas and RF signal processing. Billing, subscription and call routing functions are normally provided within the BSC 10 or by using other systems coupled to the BSC 10 that are not shown. Generally, separate CDMA cellular systems are used either by different service providers or by the same service provider when the number of base stations 12 needed to service an area exceeds the P1713 / 98MX capacity of a single BSC 10. As shown in Figure 1, the subscriber unit 18C is interconnected with a single base station 12 while the subscriber unit 18A is interconnected with multiple base stations 12. The interconnection condition or condition with multiple base stations 12 at the same time is referred to as soft transfer. The soft handoff can be contrasted with hard handoff, during which the subscriber unit loses a first interface or connection to a base station before establishing a second interface or interconnection with another base station. Soft transfer increases the diversity of signal sources for a corresponding subscriber unit since multiple connections are maintained during communication throughout. Due to this increase in the diversity of signal sources, soft transfer is usually considered superior to hard transfer. However, hard handover is performed in most non-CDMA wireless cellular systems, because each adjacent base station uses a different range of RF frequencies to conduct telephone calls and most of the subscriber units. they can only operate at a single frequency band at any given moment.

P1713 / 98MX To perform smooth transfer within a cellular CDMA system, in accordance with IS-95, each BSC 10 must perform several functions. These functions include selecting the best case of downlink data from a set of received downlink data cases (data selection), as well as generating multiple cases of uplink data for transmission to the subscriber unit 18 (broadcast of data) . The multiple cases of the downlink data are generated during a smooth transfer by the set of base stations 12 with which the subscriber unit 18 has established an interconnection. Inversely, each case of the uplink data generated serves to transmit them to a base station of the same set of base stations 12. A description of the procedures associated with a method for effecting a soft transfer is set forth in U.S. Patent 5,267,261, entitled "MOBILE ASSISTED SOFT HANDOFF IN A CDMA CELLULAR COMMUNICATIONS SYSTEM", assigned to the assignee of the present invention and incorporated herein as -reference. Additionally, each BSC 10 performs various power control operations, necessary for the proper operation or operation of a CDMA cellular telephone system as set forth in IS-95 and a description of a P1713 / 98HX implementation in U.S. Patent 5,056,109, entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM", assigned to the assignee of the present invention and incorporated herein by reference. Another feature used in CDMA cellular telephone systems is a smoother transfer. The smoother transfer is the state or condition of simultaneously interconnecting two sectors 20 of the same base station 12, as illustrated by the subscriber unit 18B. In general, the multiple cases of the downlink RF signal received from a subscriber unit 18B in a smoother transfer are combined within the associated base station 12 and the resulting single downlink data set is transmitted to the BSC 10. associated. Similarly, any duplication of the uplink data that will be transmitted from each sector to the subscriber unit 18 in a smoother transfer is performed within the associated base station 12. As shown in FIG. 1, the subscriber unit 18C is located between the coverage areas 15 of two base stations 12 which are coupled to different BSC 10 and, therefore, on the edge of two CDMA cellular systems. . To provide the complete P1713 / 98MX mobility within a metropolitan region, it is desirable to allow the 18C subscriber unit to transition to the second cellular CDMA system while continuing the call, since many metropolitan areas and other regions are large enough to require multiple cellular systems of CDMA for full coverage. While the BSC 10 processing the call could be switched as the subscriber unit 18C moves from the first CDMA cellular system to the second CDMA cellular system, the switching of the BSC 10 would avoid the use of soft transfer techniques conventional, since no single BSC 10 would have access to all the information generated by the first and second base stations, which would be necessary to perform data selection and data dissemination during transmission. Without data selection and without data dissemination, soft transfer can not be performed normally. While a hard transfer similar to that performed in non-CDMA cellular telephone systems may be used, during which the BSC 10 processing the call is switched, hard transfer is less desirable than soft transfer, as indicated above. , and the realization of a hard transfer within a CDMA cellular telephone system is especially difficult, because the use of it P1713 / 98MX frequency in adjacent base stations generates interference not present in non-CDMA systems. Therefore, a system and method that allows a call to be processed through CDMA cellular systems that support smooth transfers across edges or boundaries of CDMA cellular systems is highly desirable. The present invention is directed to said system and method.

SOMARIQ OF THE INVENTION The present invention is a novel and improved method and apparatus for processing wireless telephone calls or other communications through CDMA cellular telephone systems that support the performance of soft intersystem CDMA handoffs. In accordance with the present invention, when a subscriber unit crosses or traverses from a first cellular CDMA system to a second cellular CDMA system, the base station controller determines whether sufficient network resources are available to conduct a smooth transference. intersystems If so, the base station contributor generates a set of signaling messages that causes the call processing resource to be allocated and the call to be processed in the second CDMA cellular system. The driver of P1713 / 5SHX The base station then executes the data selection and data broadcast of the call by transmitting data to the subscriber unit by means of the second CDMA cellular system, as well as by means of one or more base stations to which the controller is directly coupled. Base station. The determination of whether sufficient network resources are available to conduct soft intersystem transfer is based on the type of connection that exists between the first CDMA cellular system and the second CDMA cellular system, the number of intersystem calls that are being conducted and of the frame shift of the call that is currently being processed.

BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES The features, objects and advantages of the present invention will be more evident from the detailed description set forth below, when considered together with the drawings, in which similar reference characters are identified. correspondingly in the present and, where: BRIEF DESCRIPTION OF THE DRAWINGS The particularities, objects and advantages of the present invention will be more evident from the detailed description set forth below when P1713 / 98MX consider together with the drawings, in which the reference characters are used consistently herein and, where: Figure 1 is a diagram of a set of cellular systems configured in accordance with the prior art; Figures 2A-D are diagrams of a set of cellular systems configured in accordance with one embodiment of the invention serving a subscriber unit in various locations; Figure 3 is a flow diagram illustrating the steps taken to determine whether sufficient interconnection resources are available to conduct a soft intersystem transfer; Figure 4 is a block diagram of a base station controller configured in accordance with an embodiment of the invention; Figure 5 is a message diagram illustrating the messages transmitted during the soft intersystem transfer establishment procedure when performed in accordance with one embodiment of the invention; Figure 6 is a message diagram illustrating the messages transmitted during a soft intersystem transfer breakdown procedure when P1713 / 98MX performed in accordance with one embodiment of the invention; Figure 7 is a message diagram illustrating the messages transmitted during the softer transfer establishment procedure intersystems when performed in accordance with one embodiment of the invention; and Figure 8 is a message diagram illustrating the messages transmitted during a softer transfer break procedure intersystems when performed in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES An apparatus and method for processing a wireless telephone call or other communication through CDMA cellular telephone systems that support the performance of a soft intersystem CDMA cellular transfer is described. In the following description, the invention is set forth in the context of an interconnection or radiofrequency signal interface operating in accordance with the physical signal modulation techniques of the air CDMA protocol or in the IS-95 air. While the invention described is especially adapted for use with these signal modulation techniques, the use of other wireless telecommunications protocols is consistent with the practice of the present P1713 / 98MX invention, including protocols using CDMA signal processing techniques or other protocols that have the ability to provide the soft transfer function. In addition, it should be understood that the present invention is intended to be used with various types of communications, including communications on the basis of voice as well as communications during which information representing digital data is transmitted in addition to the voice. Throughout the application, the use and transmission of various types of information is described, including data and signaling messages. It should be understood that this information is constituted by electronic representations of these data and signaling messages that are generated by the use of electric currents, potential voltages, electromagnetic energy or a combination thereof. Additionally, the following description contains a reference to respond to various systems, as well as to the manipulation and generation of said information. In the preferred embodiment of the invention, these systems are implemented by the use of digital and analog integrated semi-conductor circuits coupled together by various conductive connections or by the use of electromagnetic signals or both. In other instances of the application, various well-known systems are described in the form of blocks.

P1713 / 98 X This is done in order to avoid making the disclosure of the present invention unnecessarily confusing. Figure 2A is a block diagram of a cellular telephone system configured in accordance with one embodiment of the invention. The base stations 22 are coupled to the base station controllers (BSC). The BSCs 20 are in turn coupled to the public switched telephone network (PSTN) 19. The subscriber unit 28 is located within coverage areas 25. As can be seen, the configuration of the cellular telephone system is similar to that shown in Figure 1, with the exception that the direct connections between the 3CSs 20 are shown. By using these direct connections, the information will be exchanged between the BSCs 20, which will allow a soft intersystem transfer to occur. In the preferred embodiment of the invention, these connections are comprised of one or more TI or El links configured to transmit data in frames. In one embodiment of the invention, the frames are indicated by the use of front and rear flags, in accordance with, for example, the HDLC protocol, the use of which is well known in the art. For those skilled in the art, various other methods will be apparent to provide an interface or interconnection based on frames, and are P1713 / 98MX consistent with the use of the present invention. While other embodiments of the invention may use other types of connections between the BSCs 20, the invention is specially designed to be used with IT or El connections, due to its availability and low cost. In fact, the ability to provide smooth transfer capability between coupled BSCs 20 through the use of IT or El connections is one of the advantages of the present invention. As indicated above, a CDMA cellular system or a "CDMA Cellular Land Network" is defined as a BSC 20 and the set of base stations 22 to which it is coupled. In Figure 2, the subscriber unit 28 is shown on the border of two CDMA cellular systems. The solid double arrow line indicates that the subscriber unit 28 has established an RF interconnection with a first base station 22 and, therefore, with the associated CDMA-cellular system. In the preferred embodiment of the invention, the RF signals used to establish this interconnection are processed in accordance with CDMA techniques. For the purposes of this application, the cellular CDMA system with which the subscriber unit 28 is shown to be currently interconnected, is the cellular CDMA system with which it is PX713 / 98MX established first a radio communication, and will be referred to as the anchor CDMA cellular system. Additionally, any subsystem associated with the anchor CDMA cellular system can be indicated as such, by using the prefix "anchor", and the name of the system, for example, "anchor BSC" and "anchor base station". Similarly, any other CDMA cellular system involved in soft intersystem transfer can be referred to as the target CDMA cell system, and any subsystem associated with the target CDMA cell system can be indicated as such by using the "target" prefix and the name of the system, for example, "target BSC" and "target base station". In accordance with the present invention, as the subscriber unit 28 moves to the target CDMA cellular system located to the right and below the anchor CDMA cellular system, the anchor BSC 20 initiates a soft intersystem transfer when generating a set of signaling messages directed towards the target BSC associated with the first cellular CDM target system. These signaling messages are transmitted to the target BSC associated with the target CDMA cellular system and request information about the number of soft intersystem transfer calls that are currently being conducted within that cellular system P1713 / 98MX of CDMA. The objective BSC 20 responds by transmitting a signaling message to the anchor BSC 20 providing the requested information. In the preferred embodiment of the invention, the requested information includes the total number of intersystem calls anchored in the first cellular CDMA target system and which has the anchor CDMA cellular system as a cellular CCMA target system, ranked by the displacement of picture. That is, the number of calls that were originated by a subscriber unit within the target CDMA cellular system but for which that subscriber unit is currently in the anchor CDMA cellular system. In the preferred embodiment of the invention, a BCS 20 internally stores this information within an intersystem call database, described in more detail below. By using this information, as well as the information stored internally, the anchor BSC determines whether sufficient network resources are available to conduct the intersystem call. The process associated with determining whether there is sufficient network capacity to make an intersystem call is illustrated by the flow chart shown in Figure 3. In step 30, the predetermined N and N_FO maxima are set based on the capacity of the network. connection between the anchor BSC 20 and the target BSC P1713 / 98HX . In step 31, the anchor BSC 20 determines the total number of intersystem calls that will be processed by the connection between the anchor BSC 20 and the target BSC in both directions (TOT). That is, the anchor BSC calculates the total number of intersystem calls either anchored in the anchor BSC 20 and directed to the target BSC 20 or anchored in the target BSC 20 and directed to the anchor BSC 20. In step 32 determines whether this total number of calls is greater than or equal to a predetermined maximum N and, if so, in step 33 the intersystem call is rejected. Otherwise, the total number of intersystem calls that will be processed by the connection between the anchor BSC 20 and the target BSC in any direction and associated with the frame offset (FO_TOT) of the call to be processed is calculated in step 34. In step 35 it is determined whether this total number is greater than a predetermined maximum N_FO, and if so, in step 36 the intersystem call is rejected. Otherwise, the intersystem call is accepted in step 37. The values for N (Maximum No. of Transported Calls) and N_FO (Maximum No. of Calls per Frame Displacement) under various conditions are provided below. Referring again to Figure 2, if enough network resources are available, the anchor BSC P1713 / 98MX generates a set of additional signaling signals that cause a call channel to be established between the anchor CDMA cellular system and the target CDMA cellular system by means of the connection between the two CDMA cellular systems and, to establish a soft intersystem transfer using this call channel for the transition from the subscriber unit to the first cellular CDMA target system. The target BSC responds to the set of signaling messages by allocating call processing resources to route the data associated with the call, and by generating signaling messages that cause the process resources of the base station 22 to be allocated. call providing the interface or interconnection for the coverage area 25 in which the subscriber unit 28 is entering. By using these call processing resources, the base station 22 in the first cellular CDMA target system (the target base station 22) ) acquires and begins to process the downlink channel generated by the subscriber unit 28, and also transmits a link channel for detection and processing by the subscriber unit 28, as indicated by the double dashed line arrow. The anchor BSC 20 continues to perform the P1713 / 98MX data dissemination and call data selection, where dashed lines illustrate the path taken by the various cases of uplink and downlink data during the course of this data processing. For the uplink data, an additional case is sent to the target BSC 20 via the call channel established between the anchor and target 20 BSCs. By using the internally allocated signal processing resources, the target BSC 20 issues the data received from the anchor BSC 20 to the target base station 22, which in turn, transmits that data through the uplink channel assigned to the call, as shown. The uplink data continues to be transmitted to the subscriber unit 28 by the anchor base station 22 originally interconnected with the subscriber unit 28. The selection is made by the anchor BSC 20 in a manner similar to that of a soft intersystem transfer , with the exception that the selection is made using the downlink data provided from the two stations, the original base station 22 and the base station 22 in the second CDMA cellular system, provided by the objective BSC 20. In this way , a smooth intersystem transfer is established, whereby the subscriber unit 28 is coupled in P1713 / 98MX bidirectional RF interconnects with two base stations 22 of different CDMA cellular systems, and the data selection and data dissemination is performed within the anchor BSC 20. Once the call has been established, the anchor BSC 20 updates the database interleaved by increasing the number of intersystem calls that are conducted with the target CDMA cellular system to the frame shift associated with the call that will be processed. As the subscriber unit 28 continues to move towards the target CDMA cellular system, in such a way that it leaves the coverage area associated with the anchor base station 22, the soft intersystem transfer ends when the air link or the air between the subscriber unit 28 and the anchor CDMA cellular system is terminated, wherein the aerial portion of the remaining intersystem call will be conducted entirely into the target CDMA cellular telephone system. The uplink and downlink data associated with the call continues to be routed from the anchor BSC 20 to the target BSC 20 via the established call channel, as shown by the broken line in Figure 2B. During the breakdown procedure, the signal processing resource within the Anchor Pass 22 processing the call is released for the P1713 / 98MX processing of other calls. Figure 2C shows the data paths used to process the uplink and downlink data as the subscriber unit enters the coverage area 25 of a second target base station 22 which is part of the same CDMA cellular network as is the first target base station 22, which in this case is the coverage area 25A. While the subscriber unit 28 is located at the boundary of the two coverage areas 25 and the soft intrasystem transfer is performed during which data dissemination and data selection is performed by the anchor BSC 20 and the data uplink and downlink travel through the paths shown by dashed lines. In this way, the so-called intersystems continue to be performed and soft intersystem transfer will be conducted within the target CDMA cellular system using the anchor BSC 20 to perform the call broadcast and the call selection. Referring again to Figure 2A, if the subscriber unit 28 proceeds alternately to the third CDMA cellular system shown above and to the right of the anchor CDMA cellular system, a second soft CDMA cellular intersystem transfer similar to the first one is established. . That is, upon receiving P1713 / 98MX the indication from the subscriber unit 28 that a pilot channel of a base station 22 associated with a third cellular CDMA system will be received above a predetermined threshold, the anchor BSC 20 first determines whether a network connection exists with the second target CDMA cellular network and, if so, it wants the associated BSC 20 so that the number of inter-system calls are actually driven. Upon receipt of that information, the anchor BSC 20 then determines whether there is sufficient capacity in the network to conduct the intersystem call and, if so, generates a set of signaling messages that cause the second intersystem call to be established. By using the call channel created in connection with the anchor BSC 20 and the second target BSC 20, the uplink and downlink data are exchanged with the stations. base 22 in the third CDMA cellular system, and the data trajectories associated with this smooth "two day" transfer are shown in Figure 2D. As can be seen from dashed lines, this second intersystem call is made while maintaining or preserving the first intersystem call, thus causing a smooth transfer to occur. intersystems that includes three CDMA cellular systems. Once the second intersystem call is established, the anchor BSC 20 updates P1713 / 98MX to the database of intersystem calls by increasing the number of intersystem calls that are conducted with the second CDMA cellular system obiective in the particular displacement of which is associated with the call. As subscriber unit 28 continues to move or move to the second target CDMA cellular system and outside the coverage area associated with the first target CDMA cellular system, the first intersystem call terminates. With the termination of the first intersystem call, the anchor BSC 20 updates the intersystem call database by decreasing the number of intersystem calls that is conducted with the first cellular CDMA target system to the particular frame shift associated with the call. If the subscriber unit 28 continues to move back to the coverage area of the base station 22 associated with the anchor CDMA cellular system, the second intersystem call ends. With the termination of the second intersystem call, the anchor BSC 20 decreases the number of intersystem calls that are conducted with the second cellular CDMA target system to the particular frame shift associated with the call. As can be seen, although the target CDMA cellular system may change during a telephone call or other particular communication, the CDMA cellular system of P1713 / 98MX Anchor remains the same. In another embodiment of the invention, the transference "smooth intersystems between CDMA cellular systems having BSCs 20 that are not directly coupled together but which are coupled by a third intermediate BSC 20. is contemplated, however, the use of this technique it is not preferred, because the delay introduced by transport through three BSCs 20 degrades the performance of the associated telephone call by an unacceptable amount, In particular, it is known that a delay of substantially more than 100 milliseconds is noticeable by the Subscriber during a telephone conversation Given the extensive signal processing that is already necessary to perform a CDMA communication, the insufficient additional time continues to allow routing through three or more BSCs 20 without noticeable delay. The configuration needed to perform this soft intersystem transfer is substantially greater than that associated with a Soft intersystems of two BSCs. Thus, the preferred embodiment of the invention provides the most efficient use of resources by not allowing smooth intersystem transfer to occur if the only connection between the BSCs 20 of the target CDMA and anchor cellular systems is by means of another BSC 20 intermediate.

P1713 / 98MX Because of this, it is desirable to provide intersystem connections between as many pairs of BSCs 20 as possible, such that a subscriber unit 28 can travel between pairs of BSCs 20 that especially serve the same region or market. Figure 4 is an illustration of a base station controller 20 when configured in accordance with one embodiment of the invention and coupled to a set of base stations 22. Each base station 22, as well as the selector subsystem 40 and the control processor Calling (CCP) 42 are coupled to the CDMA interconnect subsystem (CIS) 50. Additionally, the CIS 50 is coupled to one or more gateways 46 of the CDMA cellular terrestrial network (CCLN), which in the preferred embodiment of the invention, are coupled to other BSCs 20, as shown in Figure 2. The data services subsystem 44 is coupled to the selector subsystem 40 and to the interface or interconnection 46 of the PSTN. The CCP 42 is also coupled to an interface 48 of the PSTN. The interface 48 of the PSTN provides a switching function and in some embodiments of the invention provides billing and subscription information. In other embodiments of the invention, the PSTN interface 48 is located outside the BSC 20 and the billing or subscription information is provided P1713 / 98MX by one or more additional systems that are not shown. During the operation, the CIS 50 performs the data frame routing (frame), using a twenty-four-bit address contained in every four. In the preferred embodiment of the invention, a subset of the available space of the twenty-four-bit address is assigned to some particular BSC 20, which in turn assigns addresses of this subset to the set of internal systems and base stations 22 it controls. To transmit a frame, a transmitter system places the address of the receiving system or resource within the frame. Additionally, in the preferred embodiment of the invention, overlap between the subsets of the assigned addresses between two BSCs 20 that are coupled is not allowed. The prohibition of overlap in the address space between adjacent BSCs 20 thus reduces the possibility that the frames between the two systems are transmitted in an infinite loop. A table can contain several types of data that include traffic data and signaling data. The traffic data includes the voice and data information that will be transmitted by the subscriber, and the signaling data includes the signaling messages exchanged by the various systems in order to properly orchestrate the processing of each P1713 / 98MX call and the global operation of the cellular network. A complete signaling message can be transmitted through the use of one or more frames. The data services subsystem 44 performs any necessary signal processing to the received data, including, vocoding or decoding, conversion to the encoded pulse code modulated (PCM) data format and conversion from this format, or modulating and demodulating digital data in audio tones and from the audio tone, in accordance with the fax signal processing and standard digital modem. The CCP 42 performs the establishment and the call breakdown by allocating and releasing the resources within BSC 20 including the resource selector within the selection subsystem 40 and the signal processing resources, both within the data services subsystem 44 and base stations 22. CCLN gateways 46 perform frame filtering using the interval or address ranges associated with the CCLN for which they provide an interface or interconnection. For each telephone call or other communication processed by the BSC 20, within the selector subsystem 440 a resource selector (not shown) is assigned to perform data dissemination and data selection, as described above. In order to perform data dissemination and data selection, the selector P1713 / 98MX of resource retains a list of the set of base stations 22 with which the subscriber unit 28 involved in the call is interconnecting at any particular time and the CDMA cellular system with which that base station 22 is associated. In the preferred embodiment of the invention, this information is stored in the form of a base station ID, the network address for each base station 22 and a BSC ID for each base station 22. Using the list of base stations, the resource selector duplicates and sends the data received from the data service subsystem 44 towards one of the base stations 22 involved in the call, if it selects a single data frame of the multiple frames received from the set of base stations 22 to send to the service system 44 of data. Additionally, the selection subsystem 40 maintains a pilot database (PDB) that stores the pilot displacement of each sector of each base station and the associated base station ID and network address, as well as the information it indicates to the system CDMA cell with which the base station 22 is associated. In the preferred embodiment of the invention, this CDMA cellular system information is comprised of a BSC ID. As indicated above, the number of unique pilot trips for a system configured in accordance with the IS-norm P1713 / 98MX 95 is 512, so in the simple PDB only 512 sectors can be stored. When it is necessary for the PDB to store more than 512 sectors, the base station and the associated sectors also correlate with the pilot shifts of the border base stations 22 in one embodiment of the invention, which can be used to compare with other base stations 22 that have the same pilot displacement, so that they identify only each base station 22 and any associated sectors. The CCP 42 retains the intersystem call database described above that tracks various parameters about the BSC 20 in which it is located and the associated CDMA cellular system. These parameters include each intersystem call that will be conducted by the BSC 20 and the associated frame shift of that call, as well as the set of BSCs 20 and associated CDMA cellular systems with which there is a direct connection to the BSC 20. Additionally, the intersystem call database stores the capacity of each direct connection to another cellular CDMA system that is based on the number of TI or El links or both, which constitute the connection. The intersystem call database also stores the total number of intersystem calls anchored in the BSC 20 in which it is located.

P1713 / 98MX located. The total number of intersystem calls are summed to a subtotal by the objective BSC 20 involved in the smooth intersystem transfer, as well as the frame shift associated with the call, which produces a set of total calls, c (i, n), where i is the target BSC index 20 and n is the frame shift index. In accordance with one embodiment of the invention, the systems shown exchange various types of information by using a set of signaling messages to appropriately process a telephone call or other communication. The set of signaling messages used to effect this exchange during the various call processing procedures is shown in Figures 5-8. The vertical lines shown in Figures 5-8 are each associated with the system identified in the box at the top of each line. A horizontal arrow that runs between two vertical lines indicates the exchange of a signaling message between the associated systems. The time progresses from top to bottom, so that the horizontal lines above or above occur before the horizontal lines located further down the page. When a single message is passed through a base station 22, two arrows are displayed for the same message.

P1713 / 98MX Additionally, when only one anchor or target base station 22 is shown, multiple base stations 22 may be substituted if the soft intra-system transfer is occurring during the call processing procedure. The set of messages exchanged during the establishment of a soft intersystem transfer is shown in Figure 5. The soft intersystem transfer begins when the subscriber unit (SU) 28 generates a Pilot Intensity Measurement Report 60, which indicates the intensity of the signal of a pilot channel from a base station associated with the second CDMA cellular system that will be received by the subscriber unit 28 above a predetermined level. In the preferred embodiment of the invention, this information is supplied in the form of a set of measurements of the pilot intensity and the corresponding set of pilot offsets. The Pilot Intensity Measurement Report 60 is received by the resource selector (A-SS) within the selection subsystems 40. The selection subsystem 40 first determines whether a particular pilot channel has been received above a predetermined threshold. for a predetermined period of time. If so, the selection subsystem 40 further determines whether the pilot channel is from a base station associated with the P1713 / 98MX CDMA cellular system with which an interface with the subscriber unit 18 has not been established, using the PDB. If so, the AO selection subsystem initiates a call and smooth intersystem transfer with the base station 22 associated with that pilot channel by transmitting the BSC ID of the target BSC 12 to the CCP 44 (A-CCP) by means of the Request for Establishment 62 CATRLM_ISSHO, together with the ID of the session that identifies the call and the ID of the frame shift. The information contained in a Request for Establishment 62 CATRLM_ISSHO, is shown in Table III.

Table III. Application for Establishment CATRL ISSHO CCP 44 responds by determining if there are E1713 / 98MX direct connections to the BSC 20 associated with that CDMA cellular system when looking for an input for that cellular CDMA system within the cellular CDMA system database. If an entry is not found, the smooth intersystem transfer request is rejected by a response signaling message transmitted back to the resource selector described above. The indication that there is no direct connection to the target CDMA cell system is also provided by placing an entry for the target CDMA cell system in the CDMA cellular system database with connection capacity equal to zero. If there is a direct connection, the CCP 44 also determines if there are sufficient network resources to allow the intersystem call to occur. This determination begins when transmitting the Request 64 of Load Inquiry CALCAL_ISL that consults the cellular system of CDMA objective about the number of intersystem calls that it is processing and that it has to the CDMA cellular system of anchor for the present call as. the target CDMA cellular system. The information contained in Request 64 of Load Inquiry CALCAL_ISL is shown in Table IV.

P1713 / 98MX Table IV. Freight Inquiry Request CALCAL ISL The target CDMA cellular system responds by transmitting the Load Discovery Response 66 CALCAL_ISL to the CCP 44. The information contained in the Load Discovery Response 66 CALCAL_ISL is shown in Table V and includes the number of intersystem calls of each displacement. of frame for which the target CDMA cellular system is an anchor CDMA cellular system and for which the anchor CDMA cellular system of the present call is the target CDMA cellular system. That is, for an anchor BSC with a BSC ID equal to I, the target BSC will return the vector c (I, 1 ... 16) stored internally.

P1713 / 98MX Table V. Load Inquiry Response CALCAL ISL While in the preferred embodiment of the invention, Response 66 of Load Inquiry P1713 / 98MX CALCAL__ISL contains the number of intersystem calls that are conducted per time offset, other embodiments of the invention may transmit that information only for the frame shift of the call that will be processed, as well as the total number of intersystem calls that are conducted. In this case, the Establishment Request 62 CATRLM_ISSHO also contains the frame shift of the call that will be processed. Also, in the preferred embodiment of the invention, the target CDMA cellular system will track and store this information within the target BSC in an internally located CCP 44, although the target BSC 20 need not be configured as the anchor BSC 20. Al Using the data received in the CALCAL_ISL Load Inquiry Response 66, as well as the internally stored data as described above, the CCP 44 calculates the total number of calls using the link between the anchor and target CDMA cellular system in both directions , as well as the total number of calls that use the frame shift of the. call that will be processed in both directions. The CCP 44 then compares these results with the predetermined maxima which are fixed as a function of the speed set of the anchor CDMA cellular system as well as the number of TI or El connections used to link to the systems P1713 / 98MX CDMA anchor and objective cell phones. The maxima used in the preferred embodiment of the invention for speed sets one and two, as well as for the various numbers of links Ti and El are listed in tables VI-IX. In calculating these values, it was assumed that 35% of the intersystem calls will be soft intrasystem muted transfer within the target CDMA cellular system, of which each soft transfer additional general cross-network traffic intrasystem. Table VI lists the maximum values of various numbers of TI links in Speed Set One. Table VII lists the maximum values for different numbers of El links in Speed Set One. Table VIII lists the maximum values of various numbers of TI links in Set Two of Speed. Table IX lists the maximum values for different numbers of links El in Set Two of Speed. Additionally, each table VI-IX lists the maximum values for a signaling traffic of 5% and a signaling traffic of 10%. Regardless of the signaling traffic value of 5% or 10% to be used, it is determined by experimentation and will depend on the exact implementation and the traffic patterns associated with each BSC 20. Each row also lists the Erlang intersystem provided, a P1713 / 98MX measurement well known in the art.

Table VI Links T-l for Speed Set One Table VII. Links E-l for Speed Set One P1713 / 98MX Table VIII. Links T-l for the Set Two of Speed Table IX. Links E-l for the Set Two of Speed If the total calls calculated are greater than the corresponding maximum of total calls of the P1713 / 98MX Tables VI-IX, CCP 44 denies soft intersystem transfer in response to the signaling message to the resource selector described later. In this case, a hard transfer is replaced or the call is lost. If the calculated call total is less than the corresponding maximum of total calls in Tables I-IV, the CCP 44 initiates soft intersystem transfer by transmitting the Establishment Response 68 CATRLM_ISSHO. The information contained in the Establishment Response 68 CATRLM_ISSHO is shown in Table X.

Table X. Establishment Response CATRLM ISSHO The rejection or acceptance of soft intersystem transfer is indicated by the field of the ISHO Acceptance State. The resource selector responds to acceptance by transmitting Resource Request CRMRLM CRM 70 to the target base station 22. If P1713 / 98MX accepted the soft transfer, the target base station 22 responds by assigning a traffic channel to the call. Once the resources are allocated for the processing of the call, the target base station 22 transmits Response Resource CRMRLM_CRM 72 to the resource selector identifying the new element of the traffic channel and its address. The resource selector responds by transmitting the TCERLM_TCE Connection Request 74 to the call processing resource within the target base station 22 to establish the connection and the call processing resource acknowledges the reception by transmitting the Connection Response 76 TCERLM_TCE. The resource selector then begins supplying uplink frames 79 associated with the call to the call processing facility and indicates this when transmitting the Upstream Traffic Start Command 80 TCERLM_RLM. The resource selector then transmits the TCERLM_RLM Traffic Link Account Indicator 81 to the target base station 22 and to each base station 22 within the anchor CDMA cellular system to adjust the power control parameters. A method for performing the power control that is used in conjunction with performing the soft intersystem transfer is described in the co-pending patent application of the P1713 / 98MX United States of America presented on March 13, 1996 with serial number 08 / 614,652, entitled "METHOD AND APPARATUS FOR PROVIDING CENTRALIZED POWER CONTROL ADMINISTRATION FOR A SET OF BASE STATIONS", also assigned to the assignee of the present invention and incorporated as reference herein, as well as in the power control patents described above. Additionally, the resource selector transmits the transfer address 82 to the subscriber unit 28 which contains the uplink traffic channel that will be used by the target base station 22 to process the call. The subscriber unit 28 responds by processing the uplink channel from the target base station 22 and once the channel is processed successfully by transmitting the transfer term 84 to the base stations 22 in the anchor CDMA cellular system . The target base station 22 also begins searching for the downlink signal of the subscriber unit 28 and with successful detection, transmits the Downlink Traffic Initiation Indication 86 TCERLM_RLM to the resource selector together with the downlink 88 frames (moving pictures). The resource selector then begins the selection using the downlink frames of the target base station 22. At this point, the soft intersystem transfer has been PX713 / 98MX established and the CCP 44 updates the CDMA cellular system database to indicate an additional intersystem call that will be conducted with the objective BSC 20 using the frame shift associated with the call. Since soft intra-system transfers occur within the target CDMA cellular system as the subscriber unit 28 moves in the coverage area of other base stations 22, a set of signaling messages similar to that shown in Figure 5 is exchanged. , with the exception of messages 62 - 68. Messages 62-68 are not exchanged, since it is not necessary to determine if there is additional network capacity, since this was already taken into account in the calculation of the number values Maximum number of calls transported and maximum number of calls per frame shift, used during the establishment of the intersystem call and soft intersystem transfer. Figure 6 is a timing or synchronization diagram illustrating the signaling messages exchanged during the course of a soft transfer break when performed in accordance with one embodiment of the invention. The break begins when the subscriber unit 28 transmits a report 200 of P1713 / 98MX pilot intensity measurement indicating that the pilot channel of a base station 22 will be received below a predetermined level to the selection subsystem 40. The resource selector within the selection subsystem 40 responds by transmitting the Account Indication Command 202 TCERLM_RLM Traffic Link to the set of base stations 22 that will remain involved with the call to adjust the power control parameters. The selection subsystem further transmits the Transfer Address 204 to the subscriber unit 28 by each base station 22, which indicates that the transfer with the base station 22 in the target CDMA cellular system must be terminated. The subscriber unit 28 responds by transmitting the transfer term 206 to the resource selector, which in turn transmits the Upstream Traffic Term Command 208 TCERLM_TCE and the TCERLM_TCE Disconnect Request 210 to the base station 22 that will be lost ( D-BS). The lost base station 22 responds upon termination of the transmission of the uplink traffic frames to the subscriber unit 28 and on transmitting the Disconnect Response 212 TCERLM TCE to the resource selector, which in turn responds when transmitting the request 214 Resource Release CRMRLM_CRM to base station 22. After releasing resources P1713 / 98MX associated with the processing of the call, the lost base station 22 transmits Resource Release Response 216 CAMRLM_CRM to the resource selector. If the selection subsystem 40 also determines that the CDMA cellular system associated with the lost base station 22 has no other interface or connection with the subscriber unit 18, it notifies the CCP 42 that the intersystem call has been terminated by transmitting the Indication of Rupture 218 CATRLM_ISSHO. The information contained in the Rupture Indication 218 CATRLM ISSHO is shown in Table XI.

Table XI. Rupture Indication CATRLM ISSHOT In the preferred embodiment of the invention, the P1713 / 98MX determination that the CDMA cellular system associated with the lost base station 22 has no other interface with the subscriber unit 18, is performed by the selection subsystem 40 using the list of the base station. With the receipt of the Rupture Indication 218 CATRLM_ISSHO, the CCP 42, decreases the total number of intersystem calls between the anchor CDMA cellular system and the target CDMA cellular system anchored in the anchor CDMA cellular system and that has the associated frame offset. Figure 7 is a diagram of the signal messages illustrating the signaling messages exchanged during the smoothest transfer establishment performed within a base station 22 in a target CDMA cellular system. As indicated above, a smoother transfer is a transfer between sectors associated with the same base station 22. The smoother transfer begins when the subscriber unit 28 transmits the Pilot Intensity Measuring Report 130 to the resource selector processing the resource. call within the selection subsystem 44, which indicates that the pilot channel associated with a new sector will be received above a predetermined threshold and that it identifies the sector by means of a sector ID. The resource sector responds by transmitting the Request for P1713 / 98MX Resource 132 CRMRLM_CRM to base station 22. Base station 22 responds by transmitting Resource Response 133 CRMRLM_CRM which causes the resource selector to transmit Connection Request 134 TCERLM_RLM. The base station 22 responds by transmitting the Connection Response 135 TCERLM_RLM which causes the resource selector to transmit the Upstream Traffic Start Channel 137 TCERLM_RLM, while also transmitting uplink frames 136 to the base station 22. With the reception of Channel 137 of Starting Ascending traffic, the base station 22 begins to transmit the uplink traffic channel in the new sector and transmits the Transfer Address 139 which instructs the subscriber unit 28 to start processing the uplink traffic channel in the new sector . Once the subscriber unit 25 begins processing the uplink traffic channel from the new sector, it transmits the Transfer Term 140 to the resource selector. Additionally, the base station 22 begins to process the downlink signal of the subscriber unit 28 within the new sector and transmits the Downstream Traffic Start Indicator 142 TCERLM indicating that the downstream traffic is now being processed using the data received through the two sectors.

P1713 / 98MX Figure 8 is a diagram of the signal messages, illustrating the signaling messages exchanged during the break of a smoother transfer of an intersystem call made within a base station 22 in a target CDMA cellular system. The smoothest transfer break begins when the subscriber unit 28 transmits the Pilot Intensity Measurement Report 150 to the resource selector that processes the call within the selection subsystem 44 which indicates that the pilot channel associated with a new sector will be received below a predetermined threshold. The resource selector responds by transmitting the Transfer Address 152 which instructs the subscriber unit 28 to start the soft transfer break. Once the subscriber unit 28 finishes processing the pilot channel of the sector, it transmits the Transfer Term 154 to the resource selector. The resource selector then responds by transmitting the Upstream Traffic Termination Command TCERLM TCE together with the Disconnect Request 158 towards the base station 22. The base station 22 stops transmitting the traffic channel associated with the call from that sector and transmit Disconnection Response 160 TCERLM_RLM to the resource selector, which then transmits Request 250 of Resource Release P: .713 / 98MX CRMRLM_CRM which instructs the base station 22 to release the previously assigned resources for the processing of the call. With the reception of Resource Release Request 164 CRMRLM_CRM, the smoothest intersystem transfer break is terminated. By providing the soft intersystem transfer capability, the invention described above allows a CDMA subscriber unit 28 to cross or traverse CDMA cellular systems while maintaining at least one RF interface with a base station 22"at all times. In turn, it allows the CDMA cellular telephone service to be provided over a given service area or region through the use of multiple CDMA cellular systems, which is useful because large metropolitan areas often require the use of multiple station controllers. base to attend to or service the necessary number of base stations 22. Additionally, by first determining the number of intersystem calls that will be conducted between the anchor CDMA cellular system and the target CDMA cellular system to that particular frame shift, the The invention described above allows multiple intersystem calls to be conducted by means of the or of a single IT connection between two CDMA cellular systems in an orderly and efficient manner. By allowing intersystem calls P1713 / 98HX and the soft transfer is conducted through a Ti connection, in turn reducing the cost and complexity associated with the supply of soft intersystem transfer, while also increasing the likelihood that this connection can be established, due to the high prevalence and availability of these interconnections. In addition, when conducting a call, and intersystem transfer by interconnections between the BSCs 20, rather than by the MSCs 26 or the PSTN 19, the present invention uses the TI or El interconnections more efficiently, by allowing the sharing of the resource interconnected by multiple calls in soft intersystem transfer. Also, by using packet-based interconnects between the BSCs 20, the need to convert the traffic data into a PCM format and the conversion from that format, the process of which causes the substantial degradation of the finally produced audio information, is eliminated. Thus, a method and apparatus for making an intersystem call supporting soft intersystem transfer has been described. The exemplary embodiment provided above is to allow any person skilled in the art to make or use the present invention. Various modifications consistent with the use of the invention, will be easily P1713 / 98MX obvious to those skilled in the art and the generic principles defined herein may be applied to other modalities without using the inventive faculty. Thus, it is not intended that the present invention be limited to the embodiments shown herein but be in accordance with the broader scope consistent with the novel principles and features disclosed herein.

P1713 / 98MX

Claims (38)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A method for conducting a soft intersystem transfer of a call made by a unit of subscriber between a first cellular system and a second cellular system, comprising the steps of: a) notifying the first cellular system that the subscriber unit is entering the second cellular system; b) determining whether there is sufficient network capacity in an interconnection between the first cellular system and the second cellular system to conduct the soft intersystem transfer; c) establishing a call channel between the first cellular system and the second cellular system if there is sufficient network capacity; and d) transmitting a first case of uplink data received in the first cellular system to the subscriber unit by means of a first radiofrequency signal interconnect or interface between the subscriber unit and the first cellular system, and transmit a second case uplink data to the unit P1713 / 98MX of subscriber by means of the second cellular telephone system and a second radiofrequency interface between the subscriber unit and the second cellular system. The method according to claim 1, further comprising the step of receiving a first case of downlink data by the first radio frequency signal interface, and receiving a second case of downlink data by means of a second radio interface. radiofrequency and the second cellular system. The method according to claim 1, wherein the step of part a) is comprised of the steps of: transmitting a pilot intensity measurement report from the subscriber unit to the first cellular system through the first radio frequency interface; and determining that a pilot channel of the second cellular system will be received above a predetermined level. The method according to claim 1, wherein the step of part b) is comprised of the step of: b.l) obtaining a first total number of intersystem calls that occur between the first cellular system and the second cellular system; and b.2) determine if there is sufficient capacity P1713 / 98MX of network between the first cellular system and the second cellular system, based on the total capacity and the total number of intersystem calls. The method according to claim 4, wherein the step of part b.l) is comprised of the steps of: consulting the second cellular system by means of a query message; and receiving a second total number of intersystem calls from the second cellular system indicating a number of calls anchored in the second cellular system and having the first cellular system as an objective cellular system; and add the total seconds with the third totals of intersystem calls anchored in the first cellular system and that has the second cellular system as the objective cellular system. The method according to claim 5, wherein the step of item b.2) is comprised of the steps of: comparing the total number of intersystem calls with a first value if the first cellular system is operating at a first speed set; and compare the total number of calls intérsistema with a. second value if the first cellular system is P1713 / 98 X running at a second speed set. The method according to claim 1, wherein the step of part b) is comprised of the steps of: bl) obtaining a first total number of intersystem calls that occur between the first cellular system and the second cellular system, and a first set of subtotals of the first total corresponding to a set of frame displacements on which each intersystem call will be conducted; and b.2) determine whether there is sufficient network capacity between the first cellular system and the second cellular system, based on a total capacity and frame displacement capacity, and the first total number of soft intersystem transfers and the first set of subtotals. The method according to claim 7, wherein the step of part b.2) is comprised of the steps of: determining whether the total capacity is greater than the first total number of soft intersystem transfers; and determine if a subtotal of the set of subtotals corresponding to the frame shift of the call that will be processed, is greater than the capacity of P1713 / 98MX scroll of picture. The method according to claim 8, wherein the total capacity and frame displacement capacity depend on whether the first cellular system operates at a first speed set or at a second speed set. The method according to claim 8, wherein the total capacity depends on how many TI and El links are present between the first cellular system and the second cellular system. The method according to claim 8, wherein the cellular system operates at a Speed Set 1, the air signaling is about 5% and the frame displacement capacity is equal to: 10 if the interconnection is comprised of a link YOU; 23 if the interconnection is comprised of two IT links; 42 if the interconnection is comprised of three IT links; 62 if the interconnection is comprised of four IT links; 77 if the interconnection is comprised of five IT links; and 97 if the interconnection is comprised of six P1713 / 98MX Ti links. The method according to claim 8, wherein the cellular system operates at a Speed Set 1, the air signaling is about 10% and the frame displacement capacity is equal to: 9 if the interconnection is comprised of a link YOU; 22 if the interconnection is comprised of two Ti links; 40 if the interconnection is comprised of three IT links; 59 if the interconnection is comprised of four Ti links; 74 if the interconnection is comprised of five Ti links; and 92 if the interconnection is comprised of six Ti links. The method according to claim 8, wherein the cellular system operates in Set Two of Speed, the aerial signaling is approximately 5%, and the frame displacement capacity is equal to: 7 if the interconnection is comprised of a IT link; 18 if the interconnection is comprised of two IT links; P1713 / 98MX 33 if the interconnection is comprised of three IT links; 50 if the interconnection is comprised of four IT links; 63 if the interconnection is comprised of five IT links; and 76 if the interconnection is comprised of six IT links. 88 if the interconnection is comprised of seven IT links. The method according to claim 8, wherein the cellular system operates in Set Two of Speed, the aerial signaling is approximately 10%, and the frame displacement capacity is equal to: 6 if the interconnection is comprised of a IT link; 17 if the interconnection is comprised of two IT links; 32 if the interconnection is comprised of three IT links; 48 if the interconnection is comprised of four IT links; 60 if the interconnection is comprised of five Ti links; and 72 if the interconnection is comprised of six P1713 / 98MX IT links. 84 if the interconnection is comprised of seven IT links. 15. The method according to claim 8, wherein the cellular system functions in Set One of Speed, air signaling is approximately 5%, and frame displacement capacity is equal to: 12 if the interconnection is comprised of a link El; 39 if the interconnection is comprised of two El links; 65 if the interconnection is comprised of three links El; and 90 if the interconnection is comprised of four El links. 16. The method according to claim 8, wherein the cellular system operates in Speed Set One, the air signaling is approximately 10%, and the frame displacement capability. is equal to: 11 if the interconnection is comprised of a link El; 37 if the interconnection is comprised of two El links; 62 if the interconnection is comprised of three links El; Y P1713 / 98MX 86 if the interconnection is comprised of four El links. 17. The method according to claim 8, wherein the cellular system operates in the Two Speed Set, the aerial signaling is approximately 5%, and the frame displacement capability is equal to: 8 if the interconnection is comprised of a link The; 22 if the interconnection is comprised of two El links; 48 if the interconnection is comprised of three links El; 70 if the interconnection is comprised of four links El; and 91 if the interconnection is comprised of five El links. 18. The method according to claim 8, wherein the cellular system operates in the Two Speed Set, the aerial signaling is approximately 10%, and the frame displacement capability. is equal to: 7 if the interconnection is comprised of a link El; 21 if the interconnection is comprised of two links El; 46 if the interconnection is comprised of three P1713 / 98MX links The; 67 if the interconnection is comprised of four links El; and 87 if the interconnection is comprised of five El links. 19. A cellular telephone system for performing soft transfer of a subscriber unit, comprising: a first base station controller for transmitting uplink data to the subscriber unit and to a call channel; and a second base station controller for receiving data uplink data from the first system and transmitting the uplink data to the subscriber unit. The cellular telephone system according to claim 19, wherein the first base station controller selects the downlink data that will be further processed from the downlink data received by a first base station and from the downlink data received by the second base station controller. The cellular telephone system according to claim 19, wherein: the first base station controller tracks a P1713 / 98MX first total of intersystem calls anchored in the first base station controller and having the second base station controller as the base station target controller, and a set of subsets of the first total corresponding to how many soft transfers will be conducted using each displacement of frame, and the second base station controller tracks a second total of soft intersystem transfers anchored in the first base station controller and how many soft intersystem transfers are using each frame shift. The method of claim 21, wherein: the first base station controller consults the second base station controller about the second total and the second set of subtotals when the notification that the subscriber unit is moving to an area of coverage associated with the second base station controller, and the first base station controller determines whether a soft transfer will occur by adding the first total and the second total to give a third total and comparing the third total with a predetermined maximum, and adding a first subtotal associated with the present frame shift of the first set of displacements of P1713 / 98MX box with a second subtotal associated with the frame shift that will be processed to produce a third subtotal, and compare the third subtotal with the second maximum frame shift. 23. A base station controller for smooth transfer of a telephone call from a first base station controlled by the base station controller to a second base station controlled by a second base station controller, the telephone call has an associated frame shift , which comprises: a call control processor for tracking the total number of soft intersystem transfers anchored in the base station and a vector a total number of calls for each frame shift; and the selector subsystem for effecting data selection and call transfer to the call control processor the moment the subscriber unit is entering a coverage area associated with the Second Base Station, wherein the control processor call obtains a vector of total calls for each frame shift of the controller of the second base station and calculates the second total number of calls and a frame shift of the total calls, and P1713 / 98MX causes soft intersystem transfer to occur if the second total number of calls is less than a predetermined maximum, and the frame shift of the total calls is less than a maximum frame shift. The base station controllers according to claim 23, wherein the call control processor determines whether the coverage area into which the subscriber unit is entering is associated with a base station controller with which there is a connection of direct network 25. The base station controller according to claim 23, where the second total number of calls is calculated by adding the first total number of calls with the vector of the total calls of each frame shift. The base station controller according to claim 23, further comprising: a cellular system gateway for interconnecting the base station controller with the second base station contributor, using a packet-based connection; and an interconnection subsystem to route the frames between a selector subsystem, the call control processor and the cellular system gateway. 27. The base station controller according to P1713 / 98 X claim 26, wherein the packet-based connection is formed using at least one TI link. The base station controller according to claim 26, wherein the packet-based connection is formed using at least one link El. The method according to claim 26, wherein the selection subsystem includes a pilot database that it contains a list of base stations, associated pilot journeys and the associated network to which each base station belongs in the list of base stations. 30. A method for effecting smooth intersystem transfer of a telephone call between an anchor network and a target network, comprising the steps of: a) notifying an anchor base station controller that a subscriber unit is entering the target network; b) establish a call channel between the anchor network and the target network; and c) establishing an interface between the target network and the subscriber unit via the call channel while maintaining an interconnection or direct interface between the anchor network and the subscriber unit. The method according to claim 30, wherein the step of part b) are approximately the steps: P1713 / 98MX b.l) obtain a first total number of soft inter-network transfers that will be conducted by the network or jet; b.2) establish the call channel if the first total number plus a second total number of soft transfers will be conducted at the anchor base station is less than a maximum amount; and b.3) reject the soft handoff if the first total number plus a second total number of soft handoffs will be conducted at the anchor base station is greater than or equal to a maximum amount. 32. The method according to claim 30, wherein the telephone call remains anchored in the anchor network for what it lasts. The method according to claim 30, wherein the target network and the anchor network have a address space that is overlapping. 34. The method according to claim 30, wherein the anchor network includes a pilot database having a list of pilot channel offsets, the IDs of the associated base stations and the identification of the associated network. 35. The method according to claim 30, wherein the network identification is comprised of an ID of the base station controller. P1713 / 98MX 36. A method for effecting the breaking of an intersystem call between a cellular anchor system and an objective cellular system comprising the steps of: a) detecting that a pilot channel of the target cellular system is not being detected above a first threshold by of a subscriber unit. b) terminate the link between the target cellular system and the subscriber unit; and c) decrease the number of calls that will be conducted between the cellular anchor system and the target cellular system. 37. The method according to claim 36, wherein the step of part c) is comprised of the steps of: b.l) sending signals to the subscriber unit to stop processing of the uplink traffic channel of the target cellular system; b.2) terminate the transmission of the uplink traffic channel of the target cellular system; and b.3) release the resources within the target cellular network used to general the uplink traffic channel. 38. The method according to claim 36, wherein the step of part c is comprised of the step of decreasing the number of calls between the cellular system P1713 / 98MX anchor and the target cellular system to a frame shift associated with the so-called intersystems. P1713 / 98MX