Processing signalling messages in a mobile communication system

A method for processing signaling messages in a mobile communication system and a mobile communication system

Scope of the invention

The invention relates to a method for processing signaling messages in a mobile communication system comprising mobile stations and base stations whose base station receiver units are tuned to the same channel, wherein more than one mobile station sends a signaling message to base stations on the same channel so that said signaling messages are at least partially

Background of the invention

In radio networks with several base stations and in which the same frequencies are repeated at regular intervals, it is possible to optimize the reuse of frequencies very effectively if a sufficient number of available channels, i.e. radio frequencies, are available. Problems start to occur when there are too few channels available. This is often the case with PMR or Private Mobile Radio networks. One solution to this problem is to use the same frequency at adjacent base stations and synchronize the base stations so that the mobile stations can understand the common signal of both base stations. Such a procedure is called the use of quasi-synchronized base stations or a simulcast system. Simulcast refers to a method of growing a cell using two or more base stations with at least one radio receiver / transmitter pair on the same radio channel. The receivers of all tu30 stations listen to the same channel.

Handsets used in mobile communication systems have lower power and poorer antenna, i.e. lower antenna gain than the base station, so the handset hears the base station transmission without problems, but since the handset35 phone or other radiotelephone has much less power than the base station, the base station hears at all. To remedy this problem, additional receivers in the field connected to the main base station can be used. These are set so that the transmission of a handset, or other low-power radiotelephone, carries some of these additional receivers, although it no longer carries the actual base station, i.e., one that has both a transmitter and a receiver.

Both of these prior art solutions are characterized in that in both of them more than one geographically close receiver listens to the signaling of mobile stations on the same channel. In this case, when the mobile stations are transmitting in an area where the coverage areas of the base stations overlap, the same information arrives at the control unit of the mobile communication system from several base stations. The control unit selects one of the messages sent by the mobile stations to the base stations to be processed and discards the other messages.

Problems with the prior art solutions also occur in a situation where two or more mobile stations transmit uplink signaling in the coverage area of ​​different receivers, i.e. base stations, substantially simultaneously. This situation is illustrated in Figure 1. In it, the mobile stations x and y transmit signaling 110, 112, simultaneously. In this case, the control unit receives signals from two or more different radiotelephones at the same time, which are not mixed on the radio path. If, on the other hand, several mobile stations transmit signals in the coverage area of ​​the same receiver, the transmissions become confused with each other at the base station receiver and cannot be interpreted.

In the prior art situation described above, prior art systems can operate, for example, by directly summing the signaling messages received from different receivers before processing, thus confusing each other and none of these messages can be interpreted. Alternatively, prior art systems select one of the signaling messages received by the base stations based on, for example, signal strength or other criteria and process that signaling message. The problem with this procedure is that all other signaling messages received at the same time are destroyed and the information they contain cannot be used.

Description of the invention

The object of the present invention is to solve the problems of the solutions according to the prior art. The object of the invention is to provide a method and a mobile communication system which enables the controlled processing of signaling messages sent simultaneously simultaneously by several mobile stations on the same channel, thus received at the base stations of the system substantially simultaneously, so that operations controlled by the information contained in all those simultaneously received signaling messages can be implemented.

This new type of method for processing signaling messages in a mobile communication system is achieved by a method according to the invention, which is known from the following steps: the signaling messages received at the base stations at least partially overlap in time are stored in a memory medium, it is examined whether said signaling message sent by a mobile station has been received in several similar versions and, if so, the signaling message of that mobile station is selected for further examination, the signaling message transmitted by which mobile station at least partially at the same time as the other mobile stations is the most urgent, and the operation is performed on the basis of the information contained in said most urgent signaling message.

The invention further relates to a mobile communication system comprising mobile stations and base stations, the receiver units of which are tuned to the same channel, the base stations being connected to the control unit by means of telecommunication connections. The inventive mobile communication system further comprises means for examining which mobile station has the most urgent signaling message sent to the base stations simultaneously with the signaling messages sent by the other mobile stations at the same time and the information contained in that signaling message is to trigger the action to be performed.

The invention is based on the idea that the signaling messages sent by the mobile stations to the base stations on the same channel substantially simultaneously are stored in the memory and copies of each other are deleted from them. Next, from the signaling messages received substantially simultaneously, the one to be processed first is selected and the desired operation is performed based on the information in that signaling message. The next most urgent signaling message is then taken.

An advantage of such a method for processing signaling messages in a mobile communication system and a mobile communication system is that it solves the problems of prior art solutions.

In the method of the invention, the system, typically its control unit, does not unnecessarily discard overlapping uplink signaling messages as prior art systems do, but all signaling messages received at the same time can be retrieved and the desired actions performed based on the information contained therein.

A further advantage of the method according to the invention is that the uplink signaling capacity of the system according to the invention is higher compared to the systems according to the prior art.

List of figures

The invention will be explained in more detail below with reference to the accompanying drawings, in which Figure 1 shows a schematic diagram of a prior art solution, Figure 2 shows a schematic diagram of a solution according to the invention, Figure 3 shows a schematic diagram of a solution according to the invention the control unit of the inventive mobile communication system.

Detailed description of the invention

Figure 1 shows a schematic diagram of a prior art solution showing base stations 1-6 listening on the same signaling channel, their coverage areas 101-106 and a control unit communicating with the base stations

100. The control unit 100 may be a base station control unit located in connection with a base station. Thus, for example, in a system using additional base stations, here for example base stations 1, 3-6, the control unit 100 may be located in connection with the actual base station, i.e. having both transmitter and receiver units. The control unit 100 may be a base station controller (BSC). Furthermore, the control unit may be a Mobile Switching Center (MSC) or a Trun30 King System Controller (TRC). Figure 1 illustrates mobile stations x, y.

In the prior art situation shown in Figure 1, the mobile station x transmits a signaling message 110, 111 so that its receiving base stations 1 and 2. The base stations transmit different versions of this signaling message received to the control unit, where according to the prior art they either mix with each other or for example, the one with the higher signal strength is selected for processing.

At the same time as mobile station x has sent its signaling message 110, mobile station y has also sent its own signaling message 112 to base station 3. Base station 3 has transmitted that signaling message to missile unit 100, where it arrived substantially simultaneously with signaling message 110, 111 sent by mobile station x. This concurrency means that the signaling messages arrive at the control unit, for example, in the same TDMA time slot, or that they enter the control unit in such a way that they overlap with each other in time. In this case, according to the prior art, the control unit has taken another of the received signaling messages, for example the one with a higher signal strength. At the same time, the second signaling message has been lost and the information contained in it could not be used.

Figure 2 shows a schematic diagram of a solution according to the invention. In it, the mobile station x transmits a signaling message 210, 211 so that it is received by the base stations 1 and 2. Each base station transmits the received signaling message to the control unit 100. Further simultaneously, the mobile station y sends a signaling message 212 via the base station 3 to the control unit. Now, all signaling messages 210, 211, 212 received by the base stations arrive at the control unit 100 substantially simultaneously. This concurrency can therefore mean that the signaling messages coincide in the same time slot or that they overlap at least partially in time. In this case, the signaling messages received at the base stations and passed to the control unit according to the invention are stored in the memory means 407. Redundancy is then removed from the signaling message, i.e. it is examined whether the signaling message 977671 sent by a mobile station has been received in several similar versions. In this case, for example, in the case of Fig. 2, the signaling messages 210, 211 sent by the mobile station x are similar, so that one can be deleted from them. One way is to remove the lower quality ones, i.e. the one with a lower bit error rate or signal strength.

Next, it is examined which of the received signaling messages from which redundancy has been removed is the most urgent, i.e. one which is to be processed as a screen and on the basis of which the action is performed. The urgency of a signaling message may be determined randomly, according to the priority of the sending mobile station or according to the priority of the signaling message, for example by processing signaling messages sent by privileged mobile stations first or by processing privileged or emergency call signaling messages first. Furthermore, the urgency of a signaling message can be determined by the time of receipt of the message, so that even if the signaling messages are received substantially simultaneously, i.e. in the same TDMA time slot, the message received by the control unit absolutely first is selected for further processing. Furthermore, the mutual order of urgency of the signaling messages may be determined by the mutual order of priority of the base stations that received them. Namely, base stations may have a mutual order of priority which may favor certain base stations. For example, a base station, i.e., a base station with both transmitter and receiver units, may be preferred, or a base station in a particular geographic area may be preferred.

After the control unit 100 has processed the first, i.e. the most urgent, signaling message, the control unit processes the next signaling message stored in the memory device 407 in the order of urgency 35 and performs the desired function on the basis of the information contained therein.

In the method and system according to the invention, it is also possible that if a mobile station sending a signaling message has time to retransmit the same signaling message before the same signaling message previously sent by that mobile station has been examined by the control unit and an action has been taken This ensures that the control unit does not accidentally perform the same function twice in a row based on the information contained in the same signaling message.

Figure 3 shows a schematic diagram of a solution according to the invention in a situation where base stations 1-6 receive more simultaneous signaling messages than can be processed. Then, according to the invention, if the base stations 1-6 receive substantially more simultaneous signaling messages than can be processed, the control unit 100 instructs the mobile stations to stop sending new signaling messages for a desired time. This transmission of new messages instructed by the mobile stations to stop is done by sending an anti-transmission message 301, 302 to the mobile stations. In the case of additional base stations, the '· * · * 25 anti-transmission message 301 can be sent from the main base station or , ·: · 302.

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Figure 4 shows a control unit 100 of an inventive mobile communication system. The control unit has connections. . *. 402 for base stations 1-6 illustrated in Figures 1-3.

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The control unit has an interface unit 401 which establishes connections with base stations 1-6. The controller unit 100 further has connection means 403, which may further comprise connection means for connecting the connections. The control unit

100 further comprising memory means 407 for the base stations to store the signaling messages received at least partially overlapping in time. The controller unit further comprises means 404 for examining which signaling message 210 sent by the mobile station x5, received at least in part simultaneously with the other mobile stations y, sent to the base stations simultaneously, is the most urgent and initiating action based on the information contained in that signaling message.

The controller unit according to the invention further has means 405 for examining whether the signaling message 210, 211 sent by a mobile station x has been received in several similar versions and, if so, for selecting the signaling message 15 for further examination, which is the most suitable, e.g. best. Quality criteria can be, for example, the signal strength or bit error rate of the receiver transmitter. It should be noted that in the inventive mobile communication system, the means described above may be located in the control unit shown or elsewhere in the mobile communication system. The control unit can also be considered as an independent mobile switching center, but it also has connections 408 to other network elements, for example exchanges and other telecommunication networks.

The mobile communication system according to the invention, for example its control unit, comprises means 406 for sending transmission blocking messages to mobile stations, in response to which the mobile stations stop sending new signaling messages for the desired time.

The following describes the operation of the invention in practice. you. When two or more signaling messages 210, 211, 212 are received by the control unit 100 substantially simultaneously, according to the invention, the control unit operates as follows.

Initially, the control unit interprets all signaling messages 35 and stores them in the memory means 407. If more than one signaling message has arrived from the same mobile station, for example a radiotelephone, the control unit 100, in particular its means 405, selects one of these. The control unit then has one message from each mobile station x, y that has transmitted the signal. Next, the control unit 100, more specifically its means 404, selects a message arrival time, a message identifier, a sender priority, or a message priority or other parameter, or randomly, for some signaling message to be processed immediately. At the same time, the control unit 100 stores other messages in the queue. Next, the control unit 100 processes the messages in the queue when radio resources are available. The control unit 100 may also prevent the arrival of new uplink signaling messages during processing by sending a transmission denial message 301, 302 to the mobile stations x, y. If the radiotelephone waiting for the service has time to send the same signaling message before it has been processed,

The drawings and the related explanation are only intended to illustrate the idea of ​​the invention. The details of the method according to the invention for processing signaling messages in a mobile communication system and the mobile communication system may vary within the scope of the claims. Although the invention has been described above mainly in connection with mobile communication systems, the invention can be used in other types of telecommunication systems.