MXPA00010100A - Method and apparatus for determining dialed number digit length in fixed wireless telecommunication networks - Google Patents

Abstract

In a fixed wireless network such as a wireless local loop (WLL) network, a method for an improved call setup procedure is disclosed. The method includes detecting when a telephone set is taken off-hook by a caller, and wherein in response, a simulated dial tone is generated in the telephone set receiver. When the caller enters a phone number to the called party, a sequence of the first three digits, for example, is compared to a predetermined list of sequences stored in a look-up table. The length of the phone number is identified by matching the sequence with its associated length in the look-up table prior to the conclusion of dialing. The call setup procedure is initiated by sending the entered digits to the switching center for processing immediately after the last digit has been entered. In a first embodiment, if no sequence match is found, a"time-out"procedure is performed to determine when the last digit has been entered in order to initiate call setup. In a second embodiment, a connection is alternatively established to the switch when no sequence is found. The call setup procedure of the present invention, when a match is found, enables efficient use of the radio spectrum by not requiring an immediate connection to the switch during dialing thus potentially enhancing network capacity. Moreover, the method eliminates the need for the caller to press"send"at the conclusion of dialing making the calling experience more closely resemble that of traditional wireline service.

Description

METHOD AND DEVICE FOR DETERMINING LENGTH OF DIGITS OF NUMBER MARKED IN FIXED WIRELESS TELECOMMUNICATIONS NETWORKS FIELD OF THE INVENTION The present invention relates generally to radio-based wireless telecommunications networks such as a Wireless Local Loop. More specifically, the invention relates to a technique for determining the length of digits before the conclusion of marking, in order to automatically initiate the call configuration. BACKGROUND OF THE INVENTION [0002] An increasingly popular form of a wireless telecommunications network is a fixed radio network, more commonly known as a wireless local loop (WLL = Wireless Local Loop). A significant motivation for the increasing adoption of WLLs is their relative simplicity and cost advantage over their installation over traditional physical line networks. The relatively high cost of installing a physical line network, also referred to as a public switched telephone network (PSTN), is typically associated with the installation of transmission lines and related equipment. This is especially the case in rural and other sparsely populated areas, Where the cost of installing relatively few lines over vast distances can be very high Therefore, given the cost consideration for configuring a new telecommunications network, many operators opt for a fixed base radio solution such as a WLL that, when is coupled to the PSTN, provides subscribers with efficient access to telecommunications services Since the use of Jr radio transmission service in place of the physical line service provides considerable savings in infrastructure costs, the WLLs have typically found acceptance in a number of areas where configuration and installation costs are of primary consideration These include areas where the expansion of existing telecommunications capacity is desirable both quickly and economically. Another possible application may include uses where localized or internal communications are required. internal communications can go through a private branch exchange (PBX = Prívate Branch Exchange) that directs calls to the correct part within the localized environment Communication with external entities can be achieved by linking the PBX with the PSTN A telecommunications infrastructure of this type can be convenient in remote sites, built for operation for either short-term (as well as long-term) such as oil production sites and remote research sites, for example, to WLL networks and standard wireless mobile telecommunications networks operate in many forms that are functionally similar. For example, a radio path is used as the communication link between a transceiver unit and a service base station (BS = Base Station) operates instead of wired lines. The telephone equipment is coupled to the transceiver unit that is in wireless communication with the BS. Consequently, many WLLs operate in accordance with existing standards based on Time-Division Multiple Access (TDMA = Multiple Division Access) technologies such as the Advanced Digital Mobile Phone System (D-AMPS = Digital Advanced Mobile Phone System) and the Global System for Mobile Communication (GSM = Global System for Mobile Communication), in addition to those based on the Multiple Access technology with Code Division (CDMA = Code Multiple Division Access). Therefore, both share many of the advantages, such as relatively low installation costs and non-limited access to telecommunications services and disadvantages such as relatively long call setup times that are typically inherent with current radio-based communications.

As those familiar with technology are aware, the technique for placing a call with a radio-based network differs significantly from placing a call with the traditional PSTN network. In particular, the WLL call setup procedure is considerably different from the call setup procedure in a traditional PSTN, thus leading to a significant variation in the call experience for the user. A significant difference with the WLL call configuration is a noticeable delay in the time a user dials the number when the connection is finally made. This delay is typically in a radio-based communication system, such as cellular networks, because normally a link to the switching center (or hub) is not established immediately when dialing by the user in such a way that the spectrum radio will not be tied during marking. In a typical call setup procedure in a radio-based network, the calling subscriber provides a series of digits, which represent the telephone number of the desired party, which are stored as digital data within the telephone equipment. The digits are subsequently transmitted to the switching center to process when the calling subscriber presses the key "send" (send). This allows scarce resources of the radio spectrum to be used in an efficient way. When the appropriate verifications are completed, and if it is determined that the connection can be made, a voice channel is assigned for the call. This procedure can take several seconds and contributes to the delay perceived by the subscriber making the call. This is in contrast to the call setup procedure in a traditional physical line system where a direct connection to the switch is made immediately upon picking up the telephone. Efforts to improve the procedure for configuring calls have been made in the prior art. One approach is to verify the elapsed time between numbers dialed in an effort to determine when the user has provided the last digit so that the number can be automatically sent to the switch for processing. This method is referred to as the "end of delay interval" method and works by concluding that the marking has ended when a predetermined time has elapsed. But the disadvantage of this technique is that the elapsed time imposes an additional delay during call setup. An additional discussion of these and other techniques dealing with call setup are provided in PCT International Publication No. WO 96/3282 with title: A Radio Unit And A Method For Connecting A Fixed Subscriber Station To A WLL System (A Radio Unit And A Method To Connect A Fixed Subscriber Station To A WLL System), Published On October 17, 1996. In view of the above, an objective of the present invention is to provide a method to eliminate the action of the caller by pressing "send" (send) upon completion of the marking, so that an immediate connection is not established. to the switch while it is marked. This allows a more efficient use of the radio spectrum during the call setup procedure, thus conserving bandwidth. An additional objective is to reduce the delay in the call setup procedure, compared to prior art methods employing the "end of delay interval" procedure, to determine the digit length when dialing by providing an experience of. More called consists of fixed wireless environments compared to traditional physical line. ** COMPENDIUM OF THE INVENTION Briefly described and according to one embodiment thereof, the invention describes a method for determining the length of a telephone number before the marking conclusion, and before making a connection to the switch, by a subscriber who called in order to automatically initiate the call configuration procedure. The described method includes detecting when a calling subscriber picks up a standard telephone equipment, for example when raising the receiver. In response to the hook-up connection, a simulated dial tone is generated by a transceiver station coupled to the telephone receiver, such that the dial tone is audibly perceived by the user. The caller provides a series of digits representing the telephone number of the desired part and thereby a sequence for example of the provided three digits is compared to a predetermined list of stored sequences in a memory search table. in the transceiver station coupled to the telephone equipment. The digit length of the telephone number is identified by retrieving the length of digits associated with the corresponding sequence, which is also stored in memory, before the conclusion of dialing by the calling subscriber. The call setup procedure is initiated by sending the digits provided to the switching center to process immediately after the last digit has been supplied. If the sequence could not be identified in the comparison stage, in a first mode, a "end of delay interval" procedure is performed to determine when the last digit is supplied in order to initiate the call configuration. In a second embodiment, a connection to the switch is established in a process that is similar to the traditional physical line technique for completing the call. The present invention provides a technique that improves the call configuration procedure in a wireless environment; for example, a wireless local loop such that the calling experience is comparable when a traditional physical line call is made. In addition, the bandwidth is not used while it is being dialed, thus allowing a more efficient use of the radio spectrum. Additional aspect is that the invention also removes the need for the called subscriber to press "send" (send) and after providing the telephone number and in some cases eliminates the delay associated with the "end of delay interval" procedure. when a sequence correspondence is found These and other advantages of the present invention will be apparent upon reading e the following detailed descriptions and study of the various figures of the drawings BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with additional objects and advantages thereof, can be better understood by reference to the following description taken in conjunction with the accompanying drawings, wherein: Figure 1 illustrates a wireless local loop network (WLL = Wireless Local Loop) simplified; Figure 2a illustrates a flow diagram showing a process for a call configuration that operates in accordance with a first embodiment of the present invention; Figure 2b shows a flow diagram illustrating a process for, call configuration that operates in accordance with a second embodiment of the invention; and Figure 3 shows an exemplary lookup table that can be used in the modality. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Figure 1 illustrates a wireless local loop (WLL) network based on exemplary simplified radio. The WLL comprises a telephone sequence 100 which operates by using Dual Tone Frequency dialing tone (DTMF = Du% l Tone Multiplexed Frequency) is coupled to a transceiver station 102. The telephone equipment 100 is typically a telephone equipment. standard that is used with a typical traditional telephone line service, to improve the cost effectiveness of the net. A simulated dial tone is generated by the transceiver station 102 in a telephone receiver 100 when the user picks up the telephone. The simulated dial tone is presented as an aid to the caller, so that the telephone equipment 100 more closely resembles the operation in a traditional physical line telephone. The transceiver station 102 includes all the necessary logic and is capable of two-way radio communication over the air interface 103 with a closely located base station (BS) 10. A mobile switching center (MSC) 106 is then coupled to the BS 10 by the digital communication link 108. It should be noted that a typical WLL network comprises a plurality of BSs and that the simple BS arrangement shown is for purposes of illustration. A plurality of telephone equipment may be coupled to the transceiver station 102 and are not displayed for similar reasons. The WLL network can be operated in accordance with an established standard such as, for example, a Digital Advanced Mobile Telephony System (D-AMPS = Digital Advanced Mobile Phone System). In order to complete a call to an external telephone equipment 112, the MSC 108 is illustrated connected to the public switched telephone network 11. For connections within a localized environment, such as within a company, a private branch exchange (PBX) can or used in place of the MSC. The operation of radio communications over the air interface 103 includes the transmission of at least one control channel and a plurality of voice channels. The control channel contains command and control signals necessary for communications between the B? and the transceiver station 102 while voice channels primarily contain data involved with voice communications. At the air interface, voice channels and control channels can operate either in digital mode, analog mode, or both according to the established protocol of the network. Furthermore, when operating in digital mode, the data relating to the conversation is transmitted within one or more specified time slots, within the radio frequency carrier, while in analog mode, the data is transmitted within a carrier of radio frequency. dedicated frequency.

In accordance with an exemplary process of the present invention, a method for improving the call configuration procedure in a WLL network will be described. The method includes a technique for determining the length of a dialed number by recognizing the initial sequence of numbers supplied before that the marking is completed. Since a connection to the switch is not established during dialing, this frees up some of the radio spectrum and thus can improve network capacity. Further, the elimination of the stage that requires the caller to press the "send" key upon finishing the dialing, may have the effect of reducing the delay encountered during the call setup process in some cases. Now with reference to Figure 2a, there is illustrated a flow diagram showing the method of operating for call configuration of a first exemplary embodiment operating in accordance with the present invention. In step 200, the telephone equipment (100 in Figure 1) is picked up by the caller who wishes to initiate a call. The off-hook condition is detected by the transceiver station 102 where a simulated dial tone is generated and sent to the telephone receiver, in step 202, to notify the user that this is working properly and that the telephone is ready to accept the market. In step 204, the calling party provides the digits of the caller party, which are stored in a memory in the transceiver station 102 for further transmission to the switch for processing. As the calling subscriber provides a sequence of digits, he performs a comparison, in step 206, with a sequence and its corresponding digit length that are contained in a lookup table in the transceiver station memory. If the sequence is known, that is, a correspondence of sequence, the transceiver station waits to receive the correct number of digits as specified in the lookup table in step 208. After the correct number of digits has been provided, the transceiver station automatically initiates a "send" procedure in order to open a line to the switch and transmit the digits for processing (step 212) to complete the call If the sequence is not known (step 210), ie the sequence is not in the memory, then an "end" operation is performed delay interval "in order to determine when the marking ended The" end of delay interval "operation considers that the last digit has been provided after a predetermined period of time has elapsed during which a digit A has not been provided For example, a period of time of approximately 5 seconds can be used where "send" is generated if the telephone does not receive a imentation within the elapsed time Figure 2b illustrates a call setup process that operates according to a second embodiment of the invention The call setup process steps of the second mode are substantially identical to those of the first mode to the point of the comparison step 206 As before, when a sequence correspondence is found, the The transceiver station 102 waits to receive the correct number of digits found in the memory lookup table (step 208) before initiating the call configuration shown in step 212. If the sequence is not found, a connection is established to the switch in step 214 such that the call is completed in the conventional manner as in the traditional physical line system, step 2Í16. When the connection is configured, the transceiver station 102 sends the received digit and continues to send the received digits as provided by the user. In this implementation, the delay time is reduced compared to using the "end of delay interval" technique, but at the cost of using bandwidth that can potentially reduce the capacity of the network. In some applications this compensation may be acceptable or even preferable in markets where capacity is not a main aspect. Figure 3 illustrates an exemplary lookup table that can be employed in step 206 according to the present invention. The search table contains a series of predetermined frequencies that are stored together with their corresponding digit lengths. According to a preferred embodiment, a series of three digits is typically sufficient to identify the appropriate length of the called number. It will be noted that schemes of more complicated numbers may require a longer sequence to identify the length. In some countries, different numbering schemes can be implemented. By way of example, telephone numbers of different lengths can be assigned in some areas where particular lengths are generally associated with prefixes or sequences of three specified digits. For example, in Sweden telephone numbers are generally assigned to certain areas of the country or certain sites within a city to be six or seven digits long. Those telephone numbers having six digits are known and can easily be identified by their three-digit prefix, as indicated by the reference number 302. Similarly, those telephone numbers having seven digits can be identified through their prefixes ( 304). The information regarding the prefixes is easily obtained through the local telephone company or telecom provider where this information can be used to update the table entries, when the number scheme 'is modified. In addition, in countries that use a standardized length telephone number scheme, such as in the US, where virtually all numbers are seven standard long digits, the method can be adapted to take advantage of this situation by considering a number of seven. digits for all but a few special sequences, listed in the table, such as 911 emergency calls and operator-assisted calls, for example. When dialing a long-distance telephone number or international number, a specific prefix is usually required to be provided in order to indicate a long-distance call to the telephone company's switch. In the U.S., a calling subscriber is generally required to dial zero (or one for direct dialing) plus a three-digit area code followed by a seven-digit telephone number in order to complete the call. Similarly, an international call is identified by the digits 011 (009 in Sweden) supplied plus the country code, city code followed by the ^ telephone number. In localized environments such as those operating within a PBX, internal telephone numbers or extensions are typically four or five digits long. The search table can be configured to acquire this standard length for extensions for this environment. To dial out of the PBX environment, the caller usually dials 9 or another specified number to access an external line followed by the telephone number. The search table can also be configured to identify an external line was requested and according to this determines the number of digits that will follow when analyzing the following prefixes (308). According to the modality, the table is contained in a memory in the transceiver station equipment and can be updated to add / remove or modify entries. In networks that operate according to the Digital Advanced Mobile Phone System (D-AMPS = Digital Advanced Mobile Telephone System) IS-136, for example, data on the telephone equipment can be updated by wireless means, thus eliminating the need to manually update each phone. This capability is included in the Teleservicio-en-el-Aire (OATS = Over-the-Air-Teleservice) functions such as the Short Message Service (SmS). The transceiver station (102) can be configured to update the look-up table (Figure 3) by using the well-known SMS function, as a multi-point diffusion technique. In this implementation as known to those skilled in the art, the SMS message may be marked to indicate that a particular message contains information for the search table. This allows convenient bulk updating without having to program individual stations. It should be noted that diffusion techniques Similar ones are used in other standards such as GSM and can be used in similar fashion. The present invention contemplates a method for determining the number of digits dialed by the user before the conclusion of the marking. This allows the system to automatically initiate the call setup procedure once the last digit has been supplied, thus eliminating additional user intervention. In a previously discussed mode, a connection to the switch is not required, thus it does not require the use of the radio spectrum during marking. Furthermore, in the situation where a connection is made to the switch, the delay associated with the call setup experienced in most radio-based telecommunications is often reduced leading to a more consistent call experience compared to the traditional physical line service.

It will be understood that the modality shown here is simply exemplary and that a person skilled in the art can make variations and modifications to the process steps without departing from the spirit and scope of the invention. In particular, the invention is applicable to mobile telecommunications systems such as cellular systems in addition to fixed wireless systems. In addition, mobile terminals can be replaced by the telephone equipment and transceiver stations as described in the invention for fixed wireless applications. Still further, the invention is applicable to multi-line terminals, such as in a PBX environment, as well as in single-line terminal environments. All of these variations and modifications are intended to be included within the scope of the invention as defined by the appended claims.

Claims (13)

1. CLAIMS 1. In a fixed wireless network comprising a switching center, a base station, a transceiver station, and at least one telephone equipment, a method for initiating a call setup procedure, characterized in that it comprises the steps of: detecting a condition when a person making a call picks up the telephone; generate a simulated dial tone to be audible at the telephone equipment receiver, in response to the off-hook condition detected; receiving from the telephone equipment a series of digits supplied by the caller representing a telephone number of the calling party; compare with the telephone equipment, a sequence of the digits supplied to a list of predetermined stored sequences and their associated digit lengths in a search table; identifying the length of digits of the number supplied before the conclusion of dialing based on the length of digits associated with a sequence correspondence that is in the comparison stage; and initiate the call configuration by sending the supplied digits to process the switching center upon receipt of the last digit provided, as determined by the length of digits, and when no correspondence is found, an "end of interval" procedure is performed. of delay ", for determine the dialing conclusion in order to initiate call configuration to complete a connection to the called party.
2. 2. A method according to claim 1, characterized in that the network is operated in accordance with the Digital Advanced Mobile Telephony System (D-AMPS) standard.
3. 3. A method according to claim 1, characterized in that the supplied digits comprise Multiple Frequency tones in Dual tone.
4. 4. A method according to claim 1, characterized in that the list of predetermined sequences are stored within a memory in the telephone equipment.
5. 5. A method according to claim 1, characterized in that the predetermined list is updated by the Short Message Service functionality.
6. 6. A method according to claim 1, characterized in that processing by the switching center includes completing a connection to the called party.
7. 7. A method according to claim 1, characterized in that the switching center functions as a private exchange.
8. 8. A method according to claim 1, characterized in that at the beginning of the call configuration step, when a match is not found, the "end of delay interval" procedure is replaced when establishing a connection to the switch to complete the call.
9. 9. A fixed wireless network, characterized in that it comprises: a standard telephone equipment; a transceiver station coupled to the telephone equipment; at least one base station in two-way wireless communication with the transmitter station; a switching center coupled to the base station at least, means for detecting when the telephone equipment is picked up; means for determining when the last digit of a telephone number is supplied by the caller, by comparing a sequence of telephone number with a predetermined list stored in the telephone equipment indicative of its length; and means for sending the supplied telephone number to the switching center for processing.
10. 10. A fixed wireless network according to claim 9, characterized in that the sequence is The first three digits of the telephone number supplied or marked.
11. 11. A fixed wireless network according to claim 9, characterized in that the predetermined list is stored in a lookup table in a memory in the transceiver station.
12. 12. A fixed wireless network according to claim 9, characterized in that the processing of the telephone number includes means for completing a connection to the party to whom it is called.
13. 13. A fixed wireless network according to claim 9, characterized in that the switching center is a private exchange. SUMMARY OF THE INVENTION In a fixed wireless network such as a wireless local loop (WLL) network, a method for an improved call setup procedure is described. The method includes detecting when a telephone equipment is picked up by the caller, and in response, a simulated dial tone is generated in the telephone equipment receiver. When the caller provides a telephone number of the called party, a sequence of the first three digits for example is compared with a predetermined list of sequences stored in a search table. The length of the telephone number is identified by matching the sequence with its associated length in the search table before the marking conclusion. The call setup procedure is initiated by sending the supplied digits to the switching center to process immediately after the last digit has been supplied. In a first embodiment, if no sequence correspondence is found, a "end of delay interval" procedure is performed to determine when the last digit has been supplied, in order to initiate the call configuration. In a second mode, a connection to the switch is alternatively established when no sequence is found. The call setup procedure of this invention, when a correspondence is found, allows efficient use of the radio spectrum by not requiring an immediate connection to the switch during tagging, thereby potentially improving the network capacity. Moreover, the method eliminates the need for the caller to press "send" at the end of the dialing, making the calling experience more similar to that of a traditional physical line service.