MXPA98004125A - Supply of customs special services of local area, on communication systems of wireless access f - Google Patents

Abstract

A signaling path between a telephone exchange switch and a fixed radio access network terminal equipment supporting one or a plurality of telephone subscriber apparatuses comprises a connection of the radio base station to the switchboard of the telephone exchange by means of a Carrier transmission link and communicates with the network terminal equipment through a wireless link operating in accordance with an air interface protocol, for example, such as that described in international standard Q931. The network terminal apparatus receives a digitized signal over a digital channel of a fixed wireless access link, the digitized signal comprising a digital call setup signal and a digitized service signal. After reception of the digitized service signal, a digital call set-up signal is transmitted over a digital channel of the subscriber line. After transmission of the digital call set-up signal, the digitized service signal is converted into an analog format after which the signal in analog format is transmitted on an analog channel of the subscriber line and within a channel of band of v

Description

SUPPLY IN BAND OF CUSTOMIZED SPECIAL SERVICES OF LOCAL AREA, ON COMMUNICATION SYSTEMS OF FIXED WIRELESS ACCESS FIELD OF THE INVENTION The present invention relates to the provision of public switching services by means of signals in the voice band over a fixed wireless access system.

BACKGROUND OF THE INVENTION In standard conventional telephone service (POTS) telecommunications systems, it is known to provide residential and commercial users with a set of services known as personalized special local area services (Custom Local Area Special Services - CLASS), by means of which a subscriber can access or control the functionality provided by a telephone exchange switch to obtain information or, to configure a subscriber line. CLASS services emulate services known as "Network Services" often provided on a conventional PBX. In some cases, these are accessed when a subscriber marks a sequence of keys P1218 / 98MX predefined in your telephone set. In other cases, these services are purchased services which are automatically generated by the service provider. Examples of these services include: • Identification of the calling line - an installation by which a subscriber can identify the telephone number of an incoming call. • Integrated voicemail - where the CLASS feature is used to provide a voicemail waiting indication. These services are specified in the ITU International Standard V5.2 [International Telecommunications Union ITU-T Recommendation V5.2, obtainable from ITU Sales and Marketing Service, Place de Nations, CH-1211 Geneva 20, Switzerland, E-Mail Sales @ itu .com]. Several types of PBXs produced by different manufacturers can also support different selections of CLASS services, selections differ from one provider to another. For example, Nortel Limited (Northern Telecom) specifies its own CLASS services in its DMS-X specification, which are supported by the Nortel DMS type switches available from Nortel Limited (Northern Telecom). Referring to Figure 1 hereof, a telephone exchange switch 100 of the P1218 / 98MX prior art, comprising part of a broadband network of the prior art, the switch communicates with a piece of equipment 101 at the customer premises, on a wired transmission line 102, for example, a coaxial cable or a twisted pair of copper wire, the equipment in the customer premises supports a plurality of analog terminal equipment 103, for example, subscriber telephone sets. Between each subscriber telephone set and the switchboard of the telephone exchange there is a subscriber line comprising a voice band channel that operates to carry voice or modem traffic, typically within a band of 300 Hz to 3400 Hz and a signaling channel outside the voice band carrying the call set-up signals, normally in the range of 3800 Hz to 4200 Hz. The transmission line 102 supports a large number of these subscriber lines between the switchboard of the telephone exchange 100 and the plurality of telephone sets 103 of the subscriber. Between the corresponding telephone sets 103 of the subscriber and the equipment 101 at the customer premises, each subscriber line comprises an analog channel carrying data of the voice band and a digital channel carrying signaling data outside the speech band. Between the switchboard of the telephone exchange and the equipment in the customer's premises, the analog data, for example, voice and / or voice traffic P1218 / 98MX modem is digitally encoded by the switchboard of the telephone exchange and is sent by a multiplexed digital link of the transmission line 102, so as to produce a virtual analog data channel, to carry voice / modem data in band. Upon arrival or upon arrival at the equipment in the customer's premises, the voice band data is sent over an analog channel to the telephone set 103 of the subscriber. Thus, for each subscriber line between the telephone exchange switch and the subscriber's telephone apparatus, there is an analog data channel in the voiceband and a signaling channel outside the voiceband. In the following example, the operation of the CLASS signals providing the identification of the calling party number will be provided. To connect a call between a calling party A 104 having a first telephone number 01803 682784 and a party B 103 having a second telephone number 0171 380, on a subscriber line, the telephone apparatus of subscriber party B receives the signals of establishing digital call on a digital signaling channel outside the voice band of a subscriber line. A channel of the associated voice band, on the same subscriber line, carries a voice and / or modem traffic once the call has been established. Communication between P1218 / 98MX switchboard of the telephone exchange and the equipment in the customer's premises on the transmission line 102 is represented schematically in Figure 2 hereof and comprises a serial burst of message commands in accordance with the standard protocol, by example, V5.2 or a proprietary protocol, for example the DMS-X. In a first time slot 200, the message commands operate to provide the equipment 101 in the client's premises, the information is described in which time slots of a plurality of time slots 201, the information corresponding to a band channel of voice of the subscriber line that will be carried. For example, the V5.2 or DMS-X protocols may specify that in the voice band data corresponding to a telephone number 0183 682784 of the subscriber line be transported in a particular time slot within the plurality of slots. of time. The team at the customer's premises interprets this message and proceeds to call the telephone set of the connected subscriber which corresponds to the number 0171 380 2992 and generates ring tone signals on the particular subscriber's telephone, connecting the signals of the band of voice of the time slots specified with the telephone set of that number on the corresponding analog channel.

P1218 / 98MX The set of conventional CLASS services makes use of a parallel voice band channel between the telephone exchange switch 100 and the equipment 101 at the customer premises immediately after the call establishment. While the telephone exchange switch 100 and the equipment 101 at the customer premises are making a connection using the out-of-band digital channel between the switchboard of the telephone exchange and the network access equipment and are dialing or calling a subscriber's telephone device, the CLASS services are sent in burst modems in band via the voice band channel. The signals representing the identification of the calling line and other CLASS services are sent in band together with the voice channel to the device at the customer premises while the subscriber's telephone device is calling and, before making the connection of the subscriber. part A with part B. CLASS signals are sent from equipment 101 at the customer premises to subscriber analogue telephone 103, before, during or after the connection of part A to part B. Typically, the user's analog telephone set may indicate to a user that a service is available, for example, the identification of the calling line by a flashing light on the telephone set of the telephone set.

P1218 / 98MX user. As shown in Figure 3 hereof, CLASS services can be directed by the equipment in the customer's premises to the subscriber's analogue telephone set, in band, in analog format and in intervals between bursts of analog tone signals. call. For example, in Figure 3, between analog tone signals, there are modem bursts that carry CLASS signals, for example, a signal containing information that the calling line identification number is 0183 682784. The The modem burst is decoded by the analog telephone set and can be used to generate a liquid crystal display of the caller's number on the telephone set. By means of the above mechanism, CLASS services, similar to those provided in conventional digital telephone sets over wired transmission lines, may be available in analog telephone sets compatible with CLASS. There is a large number of legacy access networks where the switchboards are connected to the access network apparatus by cabling, for example coaxial cable or wire pairs. However, the deployment of this access network is expensive, due to the installation of the cabling P1218 / 98 X between the customer's premises and the residential or commercial premises. Normally, this wiring is done on aerial telegraph poles or in ditches or underground conduits. Trenching costs for the installation of new wiring can normally be of the order of $ 100 per meter and, the installation of new wiring can include a considerable alteration in a neighborhood. As an alternative to the wiring between the access network apparatus and the residential / commercial premises, it is known to install a fixed wireless access system (fixed wireless access or FWA) (otherwise known as fixed radio access or FRA or local wireless circuit or WLL) in which the telephone exchange apparatus communicates with the terminal equipment of the network at the subscriber's premises via a wireless link. As illustrated schematically in Figure 4 hereof, a radio terminal equipment 400 terminal of the network at a subscriber's premises communicates with a radio base station 401 that provides cellular coverage normally within a radius of 5 to 2 kilometers in urban environments . The wireless link operates normally in a frequency band centered at 3.5 GHz. Each base station is connected to a telephone exchange switch via a haul link comprising a conventional wired transmission link, a microwave link or a wired link.

P1218 / 98MX fiber optic. However, while the fixed wireless access link provides a good cost / benefit replacement for wiring in the access network, the conventional fixed wireless access link does not provide support for CLASS services.

SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided, in a terminal apparatus of the wireless and fixed access network, a method for supplying service signals transported in a voice channel of a subscriber line, the method comprises the steps of: receiving a digitized signal over a digital channel of a fixed wireless access link, the digitized signal comprising a digital call setup signal and a digitized service signal; transmitting the digital call set-up signal along a digital channel of the subscriber line; convert the digitized service signal into an analog format; and transmit the analog service signal on an analog channel of the subscriber line and within a P1218 / 98MX voice band channel. In a first preferred embodiment, the analog service signal is transmitted to a conventional analogue telephone set of the subscriber. In a further preferred embodiment, the analog service signal is transmitted to a facsimile machine. Suitably, the step of converting the digitized service signal into an analog format comprises remodulating the service signal as a shifted frequency signal. In accordance with a second aspect of the present invention, there is provided a terminal apparatus of the wireless and fixed access network comprising: a transceiver means capable of receiving a digital signal comprising a call set-up signal and a digitized service signal; a digital-to-analog converter capable of converting the digitized service signal into an analog service signal format; and a transmission means for transmitting the analog service signal in a voice band of an analog channel of a subscriber line. In a first preferred embodiment, the analog service signal is transmitted to a conventional analogue telephone set of the subscriber.

P1218 / 98MX In a further preferred embodiment, the analog service signal is transmitted to a facsimile machine. Suitably, the digital-to-analog converter capable of converting the digitized service signal into an analog service signal format comprises means for remodulating the service signal as a shifted frequency signal.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURES For a better understanding of the invention and to show the way in which it can be put into practice, only modalities, methods and specific processes according to the present will be described below by way of example. invention with reference to the accompanying drawings, in which: Figure 5 schematically illustrates a signal path between a telephone exchange switch and a terminal apparatus of the network including a fixed access wireless link in general form; Figure 6 illustrates schematically a signaling or signal sending sequence, in accordance with a specific instrumentation of the present invention, in which the signaling of the in-band service is digitally multiplexed with the call set-up signaling and transmitted from a P1218 / 98MX radio base station towards a network terminal equipment; Figure 7 schematically illustrates a method of operating a radio base station configured in accordance with the instrumentation; and Figure 8 illustrates schematically the configuration of a radio base station in terms of functional elements that support the specific instrumentation of the present invention.

DETAILED DESCRIPTION OF THE BEST WAY TO CARRY OUT THE INVENTION The best ways contemplated by the inventors to carry out the invention will be described below by way of example. In the following description, numerous specific details are set forth in order to provide full understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention can be practiced without using these specific details. In other cases, well-known methods and structures have not been described in detail so as not to make the present invention unnecessarily confusing. In this specification, the terms "voiceband path" and "voiceband channel" are used herein with respect to signal transmissions between the switchboard of the telephone exchange 500, the P1218 / 98MX base station 504 and subscriber transceiver 503 to refer to a path or channel allocated for the transmission of the speech band signals intended for analogue reception of the subscriber in analog form within the speech band. Normally, but not exclusively, these signals can originate in the range of 300 Hz to 3400 Hz and can comprise analog data that has been converted to a digitally encoded format and which can be sent over a multiplexed digital link. Similarly, the terms "out-of-band path" and "out-of-band channel" when used in relation to signal transmissions between telephone exchange switch 500, base station 504 and subscriber's transceiver 503 are used in the present one to refer to a digital channel assigned for the transmission of signals intended for reception outside the voice band in an analog subscriber apparatus. Normally, this signaling data may originate in the range of 3800 Hz to 4200 Hz, although the invention is not limited to this range. The term "voice band" as used herein, refers to a set of frequencies in the normal range of human audio and as conventionally used to carry audio signals in a P1218 / 98MX subscriber line of a telecommunications system. Normally, a voice band extends over a frequency bandwidth of about 3300 Hz and, typically in the range of 300 Hz to 3600 Hz and, the terms "in band" and "in the voice band" are interpreted as signals that occupy a voice band. The term "out of band" shall be construed in accordance with the foregoing as signals that are outside the voice band. In this specification, the term "subscriber line" is used to refer to a communication channel that connects a telephone exchange switch with an element of the subscriber apparatus capable of receiving analog signals. Normally, but not exclusively, this element of the subscriber's apparatus may comprise a telephone apparatus or a facsimile machine. Referring to Figure 5 hereof, a signal path of a subscriber line between a conventional telephone exchange switch 500 and a network terminal equipment 503 comprising a subscriber transceiver serving or servicing the subscriber is illustrated by way of example. a plurality of conventional analog telephone sets 501, 502 of the subscriber. The signal path comprises a radio base station 504, the base station communicates with the telephone exchange switch via a haul transmission link 505, the link Transport transmission P1218 / 98MX comprising, for example, a copper wire line, a microwave permanent link or an optical fiber cable; the base station 504 will be provided with a transceiver and antenna arrangement 506 that communicates with a plurality of the terminal equipment of the network, each serving or serving one or a plurality of subscriber telephone sets. Typically, each base station can communicate with a plurality of subscriber transceivers, over a corresponding respective plurality of wireless transmission links 507, the transmission links are in a centered frequency band of approximately 3.5 GHz and have a range of up to 20 kilometers. . The base station 504 incorporates a conventional message interface that supports CLASS services, in accordance with a conventional protocol, for example, V5.2 or DMS-X protocols. The base station antenna and transceiver array 506 communicates with the plurality of the terminal equipment 501, 502 of the network using an air interface protocol, such as a Q931 digital air interface protocol. The path of the signal comprising the haul transmission link 505 and the base station 504, replaces the transmission wired line 102, the transmission wireless link 505 and P1218 / 98MX the subscriber transceiver 503 replaces the wiring between the equipment 101 at the customer premises and the telephone sets 103 of the prior art wired system shown in Figure 1 hereof. Each subscriber line between the telephone exchange switch and the network terminal equipment comprises an out-of-band signaling path and a data path of the speech band along its entire length. A voiceband path of a subscriber line terminating in a subscriber telephone apparatus 501 comprises a voiceband data channel 513 between the telephone exchange switch and the base station; a wireless voice band data channel 509 between the radio base station 504 and the network terminal equipment 503 and a voice band channel between the network terminal equipment 503 and the telephone set 501 of the subscriber. An out-of-band path of the subscriber line comprises an out-of-band data channel 512 between the telephone exchange switch 500 and the radio base station 504; a wireless out-of-band data channel between the radio base station 504 and the network terminal equipment 503; and an out-of-band channel between the network terminal equipment 503 and the telephone set 501 of the subscriber. In practice, the digital signaling channel 512 and the voice band channel 513 can be elements P1218 / 98MX different from the same multiplexed signal channel, for example, a TDMA signal or a CDMA and, similarly, the digital signaling channel 508 and the voice band channel 509 may be different elements of the same signal channel multiplexed However, there is a timing problem that prevents the incorporation of in-band CLASS services to analog telephone sets over the fixed wireless access system as will be described by the following example: Referring to Figure 5 hereof, with the creation of a connection from part A to part B, for example, between a telephone set 510 of subscriber A through a public switched telephone network 511 which includes a telephone exchange switch 500 with a part B, by As an example, the subscriber telephone set 502 establishes the call on the signaling path outside the band as follows: The telephone exchange 500 sends a digital call set-up signal on the out-of-band digital channel 512 of the haul transmission line 505 and, sends CLASS service signals within the time slots of the voice band over the line of traffic carry call 505. Call set-up signals and CLASS service signals are transmitted P1218 / 98MX by the telephone exchange switch 500 substantially simultaneously. The digital call set-up signals and the in-band CLASS service signals arrive at the base station 504 substantially simultaneously. In this way, the digital call set-up signals arrive at the base station 504 with approximately the same time relationship as compared to the in-band CLASS signals, as they were transmitted from the telephone exchange switch 500. Upon arriving at the base station 504, the out-of-band call set-up signaling and the in-band service signals are retransmitted by the transceiver and antenna array 506 over the wireless link 507 to the network terminal apparatus 503. The wireless link 507 supports both the data voice / in-band modem and out-of-band call set-up data on the corresponding in-band channel 508 and the out-of-band channel 509, respectively. The 507 wireless digital link uses a retransmission process embedded in the air interface protocol (for example, the Q931) to ensure reliability and the 507 wireless link has characteristics to incur high delay. The signals transmitted over the wireless link are recognized by the network terminal equipment 503 upon receipt. If an error occurs and the P1218 / 98MX recognition is insufficient or absent, the base station 504 retransmits the signals. However, a disadvantage of this communication initiation or establishment procedure is that there may be a significant delay in the transmission over the wireless link, which may be of indeterminate duration, depending on whether the errors occur in the wireless transmission or not. The transmission delay on the wireless link 507 can be of the order of tens of milliseconds, even in a very bad case, of the order of 5 or 6 seconds. In this way, the CLASS service signals transmitted by the telephone exchange switch 500 in the voiceband path simultaneously with digital call set-up signals in the out-of-band path can not be guaranteed to reach the network terminal apparatus 503 after a short time since its transmission, due to the indeterminate and potentially long delay incurred by the digital wireless link channel. Since the band path between the subscriber transceiver 503 and a network terminal equipment, for example, the subscriber telephone apparatus 501 can not be established until the appropriate network terminal equipment has responded to the call set-up signaling, this causes a problem for the implementation of band CLASS services P1218 / 98MX transmitted in the in-band channel, because the CLASS service signals can arrive at the base station 504 before the call set-up has been achieved through signaling over the 507 wireless link. Under these circumstances, the CLASS service signals arriving at the base station 504 can not be directed to the network terminal equipment 503 because the call establishment has not yet been achieved or achieved. The call establishment process overlaps with CLASS service signaling, with the result that at the base station 504 the CLASS service signals are lost without reaching the network terminal equipment 503. In accordance with a specific instrumentation of this invention, a radio base station 504, with the reception of the digital call set-up signals and the in-band CLASS service signals from the switchboard of the telephone exchange 500, converts the CLASS service signals into a band in a suitable digital format for local storage in the radio base station and, for multiplexing and, multiplexes the CLASS service signals in digitalized band with the digital call set-up signals and transmits the multiplexed signal over the wireless air interface link (Q931) . Because the P1218 / 98MX In-band CLASS service signals are multiplexed by time division with the digital call set-up signal before transmission to the 503 network terminal equipment, in-band CLASS service signals arrive with the call setup signals in the network terminal equipment 503 in a substantially preserved timing relation of its original relation as it is transmitted from the telephone exchange switch 500. The network terminal 503 demultiplexes the received multiplexed signal and a digital-to-analog converter in the network terminal equipment converts the CLASS service signal into digitized band in an analog format, the CLASS service signal in converted analog band will be sent to the subscriber's telephone set in analog format. The specific instrumentation requires the modification of the radio base station 504 and of each network terminal equipment 503. A sequence of events in accordance with the specific instrumentation is illustrated schematically in Figure 6 of this. In step 600, the digital call set-up signals and the in-band CLASS service signals are transmitted by the telephone exchange switch 500 along the carry transmission link 505 and arrive at the radio base station 504 substantially at Simultaneously. In P1218 / 98MX the radio base station 504, the CLASS service signal is digitized and multiplexed with the digital call setup signal before transmission through the digital wireless link. Reliable communication of the multiplexed digital signal between the radio base station 504 and the network terminal equipment 503 may require an indeterminate time, usually of the order of tens of milliseconds but, potentially up to the order of a few seconds. While reliable communication will be achieved over the wireless link 507, the in-band service signals continue to arrive at the radio base station 504 and, hence, before the call set-up is achieved, these in-band signals are stored. in buffer in the radio base station 504 and may be delayed until reliable communication over the wireless link is achieved. However, with the reception of the multiplexed digital signal reliably communicated, the network terminal equipment can recover the digital call set-up signal and CLASS in-band service signals in a temporal relationship conserved with each other, so that the call set-up signals may be sent to the subscriber telephone set 501 from the network terminal equipment 503 before or substantially simultaneously with the sending of the P1218 / 98MX analog CLASS service signals to the subscriber telephone set. Referring to Figure 7 hereof, a process performed in the base station 504 in accordance with the specific instrumentation is schematically illustrated. In step 700, the digital call set-up signals are received from the telephone exchange switch 500, together with the incoming band CLASS service signals in step 701. With the detection of a digital call set-up signal received in at step 702, the received CLASS in-band signals are converted into a digitized format suitable for intermediate storage in the base station 504 in step 703 and can be delayed by storing in an intermediate manner and then multiplexed with the call set-up signals digital in step 704. The multiplexed call set-up signal and the in-band service signal are transmitted over the wireless link 507 in accordance with the air interface transmission protocol, eg, Q931, to the network terminal equipment 503. The storage and multiplexing of the digital call setup signal and the CLASS service signal in band res the temporal relationship between the call set-up signal and the band signal for the entire duration P1218 / 98MX undetermined of the delay experienced in traversing or crossing the wireless link 507. Upon reception of the multiplexed digital signal, the network terminal equipment 503 transmits a call setup acknowledgment signal on the wireless link 507, which is received by the base station 504. With the detection of the call set-up acknowledgment signal in step 706, the base station 504 stops storing the signals from the incoming out-of-band and in-band channels received on the haul transmission link. 505 and retransmits them over the 507 wireless without significant delay. Referring to Figure 8 herein, functional elements of a modified base station in accordance with the specific instrumentation are illustrated. The functional elements provided in the base station include a call setup signal detecting means 800 for detecting an incoming digital call set-up signal; an 801 codec for decoding the in-band CLASS service signals received from the telephone exchange switch 500; a zero crossing detector 802 for detecting zero crossings in the decoded band signal; an 803 digital buffer memory for delaying band signals; and, an 804 multiplexer to multiplex P1218 / 98MX the digital call set-up signals with the CLASS service signals in digitalized band, the multiplexer means directs the multiplexed digital call setup and CLASS service signals in digitized band over the wireless link 507. The functional elements described with relation to Figure 8 can be realized by modifying the coded control mechanisms within the radio base station 504. Within a modified network terminal equipment in accordance with the specific instrumentation, a demultiplexer is provided that receives the digital signal multiplexed comprising the digital call setup signal and the CLASS service signal in digitized band, the demultiplexer that introduces the demultiplexed CLASS service signals in digitized band to a digital-to-analog converter, which operates or functions to reconstitute (is say, remodulate) the signs of s CLASS band operation in analog format, typically, for example, a square wave signal with a frequency offset of 100 Hz, 1200 Hz, which is routed or sent to the subscriber telephone set together with an analog portion of the subscriber line in a substantially conserved temporal relationship with the digital call set-up signals.

P1218 / 98MX

Claims (8)

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. In a fixed wireless access network terminal apparatus, a method for supplying service signals carried on a voice channel of a subscriber line, the method comprises the steps of: receiving a digitized signal on a digital channel of a fixed wireless access link, the digitized signal comprises a digital call setup signal and a digitized service signal; transmitting the digital call set-up signal on a digital channel of the subscriber line; convert the digitized service signal to an analog format; and transmitting the analog service signal on an analog channel of the subscriber line and within a voice band channel. The method according to claim 1, wherein the analog service signal is transmitted to a conventional analogue telephone set of the subscriber. 3. The method according to claim 1, wherein the analog service signal is transmitted to a P1218 / 98MX facsimile machine. The method according to claim 1, wherein the step of converting the digitized service signal into an analog format comprises the remodulation of the service signal as a frequently shifted signal. 5. A fixed wireless access network terminal apparatus comprising: a transceiver means capable of receiving a digital signal comprising a call set-up signal and a digitized service signal; a digital-to-analog converter capable of converting the digitized service signal into an analog service signal format and a transmission medium for transmitting the analog service signal in a voice band of an analog channel of a subscriber line. The apparatus according to claim 5, wherein the analog service signal is transmitted to a conventional analogue telephone set of the subscriber. The apparatus according to claim 5, wherein the analog service signal is transmitted to a facsimile machine. 8. The apparatus according to claim 5, wherein the digital-to-analog converter is capable of P1218 / 98MX convert the digitized service signal into an analog service signal format comprising a means for remodulating the service signal as a shifted frequency signal. P1218 / 98MX