FI77764B - RADIO SYSTEM. - Google Patents

Description

1 77764

radio system

The invention relates to a radio system according to the preamble of claim 1.

Such a system is known from DE-A-1 441 130. It uses the same transmission frequency for several adjacent transmission areas (e.g. radio areas), but at different times, namely at different so-called time slots.

The invention starts from such a system with time slots, in which case it is suitable both for the structure channel of the radiotelephone network and for a nationwide paging radio device. In the following, however, the usual expression for paging radios of nationwide paging networks is used, in which case the usual designations for the radiotelephone network are given in parentheses at the beginning.

Such a paging radio enables a telephone subscriber in individual call areas (radio traffic areas) or also nationwide to transmit radio calls from a maximum of ten or twelve (dialing from up to 15 digits) numbers to the information seen in the call receiver as an optical representation and stored. To do this, a number, the so-called codeword, must be distributed by dialing a call order via the telephone network ... to a radio call center (router) which converts the call order into a radio call. Transmission of a time-limited voice message is also possible. Such a device can be integrated without existing connections into existing telephone technology in the public telephone network covering the area and can be used from any telephone connection. It is possible to transmit the callback number by radio to a subscriber who is not in the vicinity of the telephone. The callback can then take place from an arbitrary telephone in the telephone network.

When installing such a device, for example in the Federal Republic of Germany, it would be possible to divide it into paging areas, which the calling telephone subscriber can reach individually or all together (nationwide) by dialing a code number. In this case, three different call levels are formed, which have different traffic occurrences, in which case one call area can have, for example, the extent of a central relay station:

First call level:

Traffic in only one call area, i.e. the calling telephone subscriber and the called call receiver subscriber are in the same calling area. This is referred to in this case as the domicile. It is assumed that about 80% of the total traffic occurrence occurs in domiciles.

Second call level:

It comprises the occurrence of traffic on radio calls which are unloaded by a telephone subscriber in another calling area and the recipient is a subscriber of a call receiver in another calling area, i.e. so-called cross-border traffic. In this case, a traffic occurrence is assumed, which is about 15% of the total traffic occurrence.

Third call level:

It applies to radio calls that are sent nationwide. In this case, a traffic incidence of about 5% is assumed.

If now, as shown in Fig. 1, the same transmission frequency is used to transmit radio calls to three adjacent call areas A, B, C, but in one time slot method, then on this frequency, for example, within the first twenty seconds (first time slot), radio calls are transmitted only.

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3,77764 in area A, within the next 20 seconds only in call area B and within the last 20 seconds only in call area C, etc. In call areas A ', B', etc., the same transmission frequency can be used, provided that different time slots are used in adjacent call areas. Figure 2 shows this later for a differently called transmission frequency Fo, namely as a function of time t in seconds. It will be seen that this transmission frequency is transmitted within the first 20 seconds in the call areas A and A ', within the next twenty seconds in the call areas B and B' and onwards, so that no interfering interference can occur at the boundaries of the adjacent call areas.

The disadvantage of such a method is that only relatively short time slots are used for each call area. This limitation of transmission time seems all the more annoying because it arises from the requirement that transmissions in adjacent paging areas do not interfere with each other, but in fact this consideration of paging area for adjacent areas seems illogical considering that 80% of the total traffic occurrence is in any case, exist only in domicile areas. This traffic occurrence in one and the same calling area is called the home traffic occurrence. For a call area that may have a high incidence of home traffic, while a neighboring call area may have a very low incidence of traffic, it would be more appropriate to make a larger time slot available for that home area. Such a method is also actually used in the United Kingdom, where large cities have a longer time interval than rural areas, where the traffic incidence is lower (EP patent application 40 954, archive number 81 302 244). However, this method cannot often be transferred to other countries when, for example, there are large cities with a high traffic incidence in both Call Area A and Call Regions B and C.

4 77764 To circumvent these difficulties, DE patent 26 59 570 discloses a telephone and data network in which different transmission frequencies are used to distinguish between overlapping paging areas: in view of the high prevalence of home traffic in a high subscriber area, this (multi-area) area has its own residing in frequency; this is set, so to speak, on top of the different transmission frequencies of the paging areas of the area as an additional transmission frequency. The disadvantage in this case, however, is that receivers operating on different transmission frequencies in the call areas have to be switched when switching to another call area, namely either manually (which is often overlooked) or automatically (which requires a great deal of technical effort).

The object of the invention is, on the one hand, to avoid an inappropriately large limitation of the transmission time in the paging area due to the division of time slots, but on the other hand to avoid the difficulties of switching the receiver from one paging area to another when using several transmission frequencies instead of one.

This object is solved by a radio system with the features of claim 1. Preferred forms of further development are set out in the subclaims. The underlying ideas are as follows:

In a person-to-person radio or radiotelephone network for nationwide paging, where the separation of adjacent paging areas is achieved by dividing different time slots, in order to extend the transmission time in the calling area, , since these receivers are in any case used only continuously in the same area, so that there can be no difficulty in moving to another calling area with another

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5 77764 home frequency. For this category of receivers, a home frequency can therefore be provided, which can be transmitted both within and outside the time slot arranged for this call area, in which case different home frequencies are arranged in each case in order to separate adjacent call areas. These different home frequencies do not interfere with operation, since the receivers arranged for them do not leave their home area in each case.

In addition, the remaining limitation of the transmission time that occurs when the time slot of the slot system is periodically switched over through a plurality of adjacent paging areas can be circumvented by arranging a plurality of slot systems; these slot systems are mutually time-shifted from the point of view of the calling area and can fully fill the cycle; in this case, different ... transmission frequencies. Thus, one of the data periods normally transmitted in a slot reserves a transmission frequency channel assigned during the period; while the second data period allocates a second transmission frequency channel; in this case, the same data period is projected in succession during the period as often in several intersecting transmission areas (e.g., paging areas) as the period contains time slots, and each data period is reflected in only one transmission area at any given time.

The preferred embodiments of the invention are explained by means of the drawings. In the drawing: Fig. 1 shows different call areas as a map, Fig. 2 shows the relative order of call areas, time and different transmission frequencies in connection with the first embodiment, Fig. 3 schematically shows a part of a radio message which is part of a radio call, Fig. 4 shows a block diagram, Fig. 5 shows Fig. 1 Fig. 6 77764 Fig. 6 shows a frequency and time slot plan according to a second embodiment, Fig. 7 shows a part of a block diagram of a second embodiment, Fig. 8 shows one of the periods in which both embodiments transmit, Fig. 9 shows a transmission function in power units depending on the performance of the other. the frequency of the transmission amplifiers.

In Fig. 1, each call area A, B, C, A ', B' has a radio call center z (pass-through device). The various radio call centers are interconnected by data transmission lines DF.

However, part of the public telephone network may also be used instead. The radio call centers Z act as input ports for call orders coming from the public telephone network. From each radio call center, the sub-exchanges UA1, UA2 ... UAn divided via the respective call area, for example A, are handled, from which at least one dual transmitter is handled in each case, namely SAo1 / SAa1, SA02 / SAa2 ... SAon / SA. These designations relate to a first embodiment with the features of claim 1: in which case S denotes the transmitter, A denotes the paging area A, o denotes the country frequency Fo transmitted as the transmission frequency by this transmitter, A denotes the home frequency Fa transmitted by this transmitter and the numbers 1, 2, 3 ... n denote the transmitter number in the calling area. Thus, for example, the dual transmitter SB'o2 / SB'b2 is arranged in the paging area B 'as a second dual transmitter and consists of two transmitters, namely the national transmitter SB'o2 operating on the national frequency and the home transmitter SB, b2 operating on the home frequency Fb.

Fig. 2 shows, with respect to the first embodiment, depending on the time t, at what times the national frequency Fo and the home frequencies Fa, Fb and Fc may be transmitted. Thus, the national frequency in the different paging areas can only be transmitted at predetermined time intervals t1, t2, t3, while there is no time limit for the home location frequencies.

Il 7 77764

Thus, the separation of adjacent call areas A, B, C is arranged by dividing the different time slots t1, t2, t3 for the call areas for a common transmission frequency transmitted from the wireless and transmitting calls (national or time slot frequency Fo). The extension of the transmission time available in the area over the duration of the time slot is achieved by providing a second transmission frequency, the so-called home frequency Fa, but which can also be transmitted outside the time slot t1 arranged in the area A; the difference between the adjacent call areas A, B, C is then achieved at different home frequencies Fa, Fb, Fc. In addition, the home frequencies are made available only to receivers which are in any case only used continuously in the same area A.

In order to be able to call back the called receiver after receiving a radio call that has been disconnected by the telephone subscriber, it is necessary to transfer to the called receiver the network group number which he has to dial when performing the callback. In addition to the network group number, the remaining telephone numbers to be called by the calling subscriber must also be ported. The entire call number is hereinafter referred to as information. The information capacity must be sufficient for at least ten digits (when calling from abroad fifteen): in this case, it is required that the representation of the network group zero can be omitted. The set of numbers to be dialed as a telephone subscriber's call order (starting with the caller's subscriber's caller's call number) is hereinafter referred to as a call message, which in practice is supplemented at the beginning by an introduction and at the end by additional signals to confirm the code.

Such a paging message begins, as shown in Figure 3, with four digits, namely the radio call center (pass-through) identifier, followed by two so-called code numbers, followed by six digits, namely the subscriber numbers β 77764 (radio call address) of the called receiver and finally the remaining ten digits. (information), namely the telephone number of the telephone subscriber called by the calling subscriber, which is indicated on the display of the receiving subscriber.

By selecting both code numbers, which were also provided in the paging radio equipment for nationwide paging networks, the following can be achieved:

With the first code number, the calling telephone subscriber can inform the radio call center (through control device) in which call area in the radio traffic area) (maximum 9) to be called. In a nationwide radio call (code number 0), the selected radio call center forwards the call to all other connected radio call centers via a data connection (eg the basic line "Datex network"). If code number 1 is dialed, when it is known that the subscriber of the paging receiver to be called is in call area A, then the radio call center is selected in call area A. When code number 2 is selected, radio call area B is selected, and so on.

The second code number determines the paging method in known paging radio equipment for nationwide paging networks. In total, there are ten calling methods that can also be booked with different fees (different fees may also be charged for calling calls to calling areas at different distances). Invitation methods include: group call, call transfer, urgent call, etc.

What is new now is that the second code number can also be used to determine whether a radio call is made to the kingdom’s transmitter ’. via or through a home transmitter, i.e. through a country frequency Fo limited to time slots or through a home frequency Fa arranged for that calling area. In this case, the calling telephone subscriber must know which of the two types of receivers occurs at the calling subscriber's subscriber, namely either a receiver which

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77764 9 operates on the national frequency, or a receiver operating on the home frequency. In this case, receivers operating only on the home frequency are arranged for call receiver subscribers who want to be reachable only in the same call area and give up other call areas.

When, in the first embodiment, calling modes such as group calling, privileged calling, voice transmission, etc. are to be possible, two code numbers must be selectable for each of these calling modes, namely one for a radio call on the national frequency and another for a radio call on the home frequency of that calling area.

The designations of the above figures show the block diagram of the first embodiment of the radio system shown in Fig. 4. From the telephones T, radio call centers z can be reached via the public telephone network F, which are interconnected via the data transmission lines DF. From the radio call centers Z, substations UA1 ... UA are called in the call area A or resp. UB1 .. .UB in call area B, etc., which in turn control dual transmitters for sending radio calls. Radio calls are received by receivers RAa (operating in calling area A, operating on frequency band a), RB'o (operating in calling area B 'in operating area A and operating on national frequency Fo), RAo (operating from calling area A to calling area B and operating on national frequency Fo in home area B) and operating in their home area Bo Fb actions). The receivers RB'o and RAo are reached either by a directional radio call with the first code number 1 (with respect to the call area A) or vast, with the first code number 2 (with respect to the call area B) with synchronously and simultaneously transmitting transmitters (SAo1 ... SAon) in the call area A or by the corresponding call area. B with transmitters SBo1 ... SBon or - if it is not known in which calling area the receivers are currently - they are reached by the transmission of the first code number 0 on the basis of a nationwide radio call by one of the transmitters 10 77764

Sxoy, where x denotes areas A, B, C, A ', ... and y denotes code number 1, 2 ... n.

Receivers RAa and RBa, on the other hand, can only be reached within their home area and only from transmitters SAa1 ... SAan or resp. SBb1 ... via SBb in each case with their domicile frequency Fa or resp. Fb.

The network structure shown in Fig. 5 is part of the interleaving area between call areas A and B according to Fig. 1. Since this structure also serves to explain the second embodiment, the designations are chosen a little more generally than in Fig. 1. From the telephone T, a telephone network can be reached and thus, in particular, for example, the central exchange station ZVST of the call area A. An invitation processor RP is arranged for this. Both together form a call center Z. Several call processors are connected to each other via data connections, whereby they have to travel; therefore, to take over the transmission of the telephone network for its calling area. Each paging processor RP divides the paging messages assembled into data periods via the fixed line network by means of interconnected substations UA into individual paging zone A transmitters SA1, SA2, or the like, the paging zone B transmits SB1, SB2, ..., etc.

Transmission frequencies in the VHF or UHF band are appropriately used. Given the transmitters thus exist. . The small range, which is generally less than 30 km, must be used by several transmitters in the calling area synchronously 'or simultaneously in common radio or quasi-synchronous operation, in which case the radio communication areas in question must be geographically overlapping in order to provide a seamless radio connection. In addition to the high frequency stability of transmission oscillators, modulators with a high input constant are required.

In order to be able to demodulate the reception signal in the same phase with transmitters in the interleaving areas between the radio communication areas, the transmitters must be modulated in the same stages,

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11 77764 which requires travel time equalization for modulation supply lines. In larger nationwide radio systems, modulation as input lines, due to longer distances, it is no longer possible to use low-frequency cables or piped lines, but use transmission paths with carrier frequency components and also pulse code modulation systems. However, the travel time equalization of paging messages transmitted on modulation supply lines is very difficult to perform in these systems. For this reason, the aim is to use common wave radio systems in only one paging area, where low-frequency cables or pupin lines can be used to bridge the desired range.

Another embodiment will now be explained with reference to Figures 1, 5 and 6. To simplify the explanation, the term "period region" is first introduced. In this case, it is an area which, within the radio system, comprises a group of immediately adjacent call areas which overlap. In Figure 1, for example, A, B and C overlap. In order to avoid interference, it is known to provide different transmission frequency channels for paging areas on the one hand and a common transmission frequency channel on the other hand, which is, however, reserved in the time slot several times in succession for the same paging message or data period.

In the second embodiment of the present invention, additional operations are now performed, as shown in Fig. 6. Namely, in addition to the home frequencies, different transmission frequency channels are arranged, which operate on the national frequencies £ 1, f2, f3, but which are simultaneously used as common transmission channels for call areas A, B, C so that for the period a different call message or data period in each transmission frequency channel. transmitted several times in succession, but from time slot to time slot in another paging area for each transmission frequency channel of the time slots according to its own mutual order to the radio areas. In Fig. 6, time slots are denoted by symbols, 2 77764 la t1, t2, t3, and their number in the period follows the number of paging areas A, B, C occurring in the period area defined above. Figure 1 shows three calling areas that overlap. However, there could be several. According to the maximum number of radio areas overlapping the radio system, a larger number of time slots per period should then be selected.

In the radio system described here, in addition to receivers operating at only one home frequency at a time, there are three types of receivers. One type operates at transmission frequency f1, another at transmission frequency f2, and a third at transmission frequency f3. They can all be achieved in each paging area because in each paging area, the same radio calls are transmitted sequentially on all three transmission frequencies. For this reason, there is no difficulty in replacing the receiver ... from one calling area to another. Nevertheless, the receivers can be single-channel devices and tuned - fixed to a single transmission frequency. This is a very economical solution. In order to achieve economy on the transmission side as well, the transmitters should be designed so that each transmitter can operate on three different transmission frequencies, so that the same transmitter only needs to be switched in the slot method from one transmission frequency to another.

The switching of the transmission frequency is preferably performed by means of an encoded switching signal.

The block diagram of Fig. 7 corresponds in part to Fig. 5. In the paging processor RP, the incoming paging messages are converted into data periods which are fed via the modulation supply lines and substations UA to the transmitter SA1 and which are similar in principle to all transmitters. The data periods each fill one time slot t1, t2, t3 and contain, as shown in Fig. 8, an introduction for time slot synchronization in the receiver E and the following paging messages, as shown in Fig. 3. Before each

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13 77764 introductions are pre-started V1, V2 or resp. V3 coded switching signal for transmission frequency switching in transmitters. Each transmitter has an address decoder D with frequency identification, so that the transmission frequency to be transmitted in each cycle can be switched; for this purpose, the address decoder D controls the crystal oscillator 0 or the synthesizer. The transmission frequency produced by the crystal oscillator O is modulated in the modulator M by an preamble and subsequent paging messages, and the modulated transmission oscillation is input to the transmission amplifier SV and finally to the antenna AT.

The broadband transmission amplifier SV has a switching bandwidth (power bandwidth) which comprises the transmission channels of the transmission frequencies f1, f2, f3 transmitted cyclically from the transmitter, so that only one transmitter and a common supply line from the substation are required at a time. Figure 9 refers to the transmission amplifier broadband. It shows the transfer function UL in units of power above the frequency f. It will be seen that the frequency spectra FS1, FS2, SF3 of the transmission channels belonging to the transmission frequencies f1, f2, f3 are in the power bandwidth BB.

In practice, the transmitters operate in continuous operation at three different transmission frequencies, whereby the switching points between the time slots are centrally controlled by the call processors for all connected transmitters in all areas synchronously.

This radio system can be used flexibly over more or less wide areas, as the size of the paging area can be varied by placing only one transmitter or several synchronized common wave or quasi-wave transmitters, with these transmitters being centrally controlled from the paging processor via substations. Multiple paging processors, in turn, can be interconnected via data lines to provide a common timeline for synchronously circulating time slots for a nationwide radio paging system. Thus, time-synchronous switching of transmission frequencies is possible in all transmitters.

Claims (10)

14 777 6 4 A radio system extending the public telephone network with mobile receivers (RAa, RB'o) and radio call centers (Z) arranged in each case for one call area (A), whereby the radio call center receives call orders which arrive indirectly or immediately from the telephone network (F) can be routed as paging messages to the radio network, in which case they decode the radio call and use the same transmission frequency, called the national frequency (Fo), for transmitting radio calls for several immediately adjacent and overlapping transmission areas; in the overlapping areas so that for the transmission of this national frequency, periodically reversible time slots (t1) are arranged for the individual transmission areas, and in that case for different, in each case with one transmission ... the transmission frequencies (Fo, Fa; f1, f2, f3) to be transmitted in the area include transmission frequency channels which can be reserved by radio calls, in particular at least one of these (Fa; f1, f2, f3) also outside a single time slot (t1), characterized in that that: - the code signal in the paging message operates for the selection of two different transmission frequencies to be transmitted in one transmission area at a time, one of which, namely said national frequency (Fo), is arranged to be transmitted only in the time slot allocated to the respective transmission area (call area A); the second is also arranged, if necessary, to be transmitted outside this time slot, in particular on a transmission frequency arranged in this transmission area (call area A), called the home frequency (Fa), specifically for transmitting radio calls to receivers (RAa) which are continuously in this transmission area only, - adjacent transmission areas A, the call area B) the home frequencies (Fa, Fb) differ from each other and from the kingdom frequency (Fo). Il 15 77764 Radio system according to Claim 1, characterized in that the transmission areas are radio traffic areas or paging areas (A, B) of the radiotelephone network, on which one pass-through device or radio call center (Z) is arranged in each case. Radio system according to Claim 1 or 2, characterized in that a plurality of synchronously operating home transmitters SAa1, SAa2 .. .SA) and a national frequency (Fo) are provided in the transmission areas (call areas A) for transmitting the home frequency (Fa) in the transmission area (call area A). , B) a plurality of synchronously functioning national transmitters (SAo1, SAo2, ..., SAon; SBo1, ..., SBon) are arranged, operating in time slots arranged by regions. Radio system according to one of Claims 1 to 3, characterized in that two types of paging receivers are provided, namely a type (RAa, RBb) which is designed as a fixed-tuned single-channel receiver (E) and which is only suitable for reception at the home frequency ( Fa, Fb), and another type (RB'o, RAo), which is also suitable or as a fixed-tuned single-channel receiver exclusively for receiving the national frequency (Fo). Radio system according to Claim 4, characterized in that in each so-called period area, which consists of the largest number of immediately adjacent and overlapping transmission areas (A, B, C), the same transmission frequency (Fo, f1) is allocated during the period at the same time intervals. number several times in a row with the same radio calls, specifically for each transmission area (A, B, C) of the period area once. Radio system according to Claim 5, characterized in that a second country frequency channel (f1, f2, f3) is arranged in each transmission area (A) in the period area (A-B-C) and for one time slot, and this,. Τ7Ί 64 The order <fl / A> is changed cyclically for the period and the time interval at the rate. Radio system according to Claim 6, characterized in that the transmitters (SAI, SB1) in each case have a power bandwidth which comprises the transmission channels <f1, f2, f3> of the transmission frequencies to be transmitted periodically from the transmitter. Θ. Radio system according to Claim 6 or 7, characterized in that for the switching of the transmitters to the individual transmission frequencies <f 1, f2, f 3>, each transmitter (SAI) comprises a decoder (D) which switches from the paging processor at the time of the time slots produced by the radio intercom. to the frequency required by the oscillator or counter synthesizer. Radio system according to one of the preceding claims, characterized in that the time slots (t1, t2, t3> arranged in the individual transmission areas are controlled by time-slot signals which are routed via modulation lines to individual transmitters (SAI), in particular national transmitters (SAol,. .., SAon), and that the time-clock signals arrive at the transmitters as a pre-start (VI) at the beginning of each data period formed from the plurality of paging messages arranged for the time slot. Radio system according to one of the preceding claims, characterized in that paging receivers are arranged for receiving radio calls, which are suitable for storing the information transmitted by the radio call for display on the display with a signal, and for transmitting the address and information and possibly speech transmission to the paging receiver. channel. Il 17 77 7 6 4