FI104606B - Defining a Service Status in a Packet Radio Network - Google Patents

Description

104606

Determining the Service Situation in a Packet Radio Network “Background of the Invention

The invention relates to a method for communicating a service situation in a telecommunication connection to a subscriber.

The invention is primarily described in connection with packet radio systems such as GPRS, but it can also be applied to other types of telecommunication systems. Figure 1 shows the essential parts of the packet radio network for the invention. The mobile stations MS (Mobile Station) communicate with the Base Transceiver Station (BTSn) over the air interface Um. The base stations are controlled by the Base Station Controllers BSC, which are connected to the Mobile Switching Center MSC. The subsystem controlled by the base station controller BSC - which includes the base stations BTSn controlled by it - is collectively referred to as the Base Station Subsystem (BSS). The interface between the exchange MSC and the base station subsystem BSS is called an A-interface. The MSC side of the A-interface exchange MSC is called the Network Subsystem (NSS). Similarly, the interface between the base station controller BSC and the base station BTS is called the Abis interface. The MSC is responsible for connecting incoming and outgoing calls. It performs the same type of tasks as the PSTN exchange of the public telephone network. In addition to these, it also performs functions specific only to mobile call traffic, such as location management of subscribers, in cooperation with network subscriber registers, which are not shown separately in Figure 1.

Conventional radio communication used in digital mobile communication systems is circuit switched, which means that radio resources reserved for the subscriber are kept dedicated to that connection throughout the call. GPRS (General Packet Radio Service) is a new service designed for digital mobile communication systems such as GSM. The packet radio service is described in ETSI Recommendations TC-TR-GSM 02.60 and 30 03.60. With the packet radio service, the user of the mobile station MS can be provided with a packet radio connection utilizing radio resources efficiently.

* In a packet switched connection, radio resources are reserved only when there is speech or data to be transmitted. Speech or data is compiled into fixed-length packets. When such a packet is transmitted over the air interface Um, and the transmitting-35 slot party does not immediately have the next packet to be transmitted, the radio relays can be released for use by other subscribers.

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The system of Figure 1 comprises a separate GPRS service control node, or SGSN (Serving GPRS Support Node) 15, which controls the operation of the packet data service on the network side. This guidance includes e.g. mobile connections to and from the system (Logon and 5 Logoff, respectively), mobile location updates and routing of data packets to the correct destination. In the context of this application, "data" broadly refers to any information transmitted in a digital mobile communication system, such as digital encoded speech, computer-to-computer data transmission, or telefax data. The SGSN may be located at base station BTS, base station controller BSC, or MSC. The interface between the SGSN and the base station controller BSC is called the Gb interface.

In a packet radio network, one can imagine a situation in which a subscriber using a PC is connected to another computer 14 via a packet network 15 10, a data network 11, a router 13 and a local area network LAN. There is a long data transfer between PCs and 14 or a number of consecutive short data transfers, for example according to the Internet FTP policy. At the same time, the PC PC user or another subscriber initiates an interactive session according to, for example, the Internet Telnet policy. If the packet of each turn-20 active session had to wait at the nodes on the connection until the long data transfer had been completed, the response times of the interactive session would be so long that the use of the service would no longer be meaningful.

Network operators typically define several different service classes (QoS, Quality of Service) such that in the higher service class, the latency (and possibly also the probability of packet loss) is lower than in the lower service class. In the present invention, the most important parameter associated with the service class is the latency. For example, an operator may define three classes of services for which two TAVE and T95 delay times are defined, the first (TAVE) defining the average packet delay in the operator's network and the second (T95) defining such that 95% of packets are transmitted with a delay less than T95. For example, the correspondence between service classes and transit delays could be as follows:

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Table 1, Typical Service Class and Delay Correspondence: Service Class TAVE (ms) T95 (ms) r 1 400 1000 2 800 2000 3 1600 4000 (Obviously, these values are only examples. There may be more than three service classes, instead of the arithmetic mean use the median and other percentages may be used instead of 95%.)

There are several problems with the arrangement described above. For example, there are no predefined policies for communicating the current service situation to the user and / or application programs, and there are no defined policies that allow application programs to automatically adjust to changes in the service situation. Although users or application programs may independently evaluate or determine the current service situation of the service category being negotiated, users or application programs cannot independently obtain information about other service categories and thus cannot make an objective determination as to whether the service category should be renegotiated to a higher or lower level.

Brief Description of the Invention

The object of the invention is thus to provide a method for solving the above problems. The objects of the invention are achieved by a method characterized by what is stated in the characterizing part of claim 1. Preferred embodiments of the invention are claimed in the dependent claims.

The invention is implemented in its simplest form by providing a method of detecting a service situation in a packet radio network comprising at least one base station BTS and at least one terminal device (mobile station MS and possibly a computer PC connected thereto). According to the invention, at least one parameter describing the service situation of the packet radio network is determined and this parameter is made available to the terminal (MS, PC). In this case, the terminal (the person using it and / or the application program running on it) will have an exact and available. 30 objective information on the network service situation. For example, the user and / or application program may • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • In this case, the application program or its user may conclude that the delay may be due to server load, whereby negotiating a service class for improvement does not improve the situation. Such an inference cannot be made objectively if the service situation is determined by the terminal subjectively (by estimating or measuring the effective data rate) because the terminal or its user cannot distinguish network delays from server delays.

According to a preferred embodiment of the invention, the network determines the prevailing service situation in each service class and this information is communicated to the terminal. In this case, the terminal (or its user) has access to objective information about service situations in other service categories. The terminal application or its user may then decide to negotiate a higher or lower class of service as needed.

According to another preferred embodiment, the service situation prevailing at the neighboring base station is used as a criterion in connection with the handover, whereby the mobile station can be switched to a base station with lower reception but better service (less load) than the base station serving the mobile station.

An advantage of the method and system according to the invention is the more efficient utilization of packet radio network resources, since users and / or applications making decisions (change of service class or handover) have objective information on the current service situation.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in greater detail in connection with preferred embodiments, with reference to the accompanying drawing, in which: Figure 1 shows the essential parts of a packet radio network for the invention.

DETAILED DESCRIPTION OF THE INVENTION As stated above, the invention is implemented in its simplest form by providing a method of detecting a service situation in a packet radio network comprising at least one base station BTS and at least one terminal (mobile station MS and possibly connected or integrated PC). According to the invention, at least one parameter describing the service status of the packet radio network is determined and made available to the terminal (MS, PC).

According to a preferred embodiment, the service situation parameter is determined in a fixed network element of the network, such as 5 base station system BSS or support node SGSN. Alternatively, said parameter can be determined in the terminal (MS, PC).

The prevailing service situation in the service class used by the mobile station MS can be determined in several ways. One possible technique is based on determining the parameter based on the capacity utilization rate of the base station system BSS, for example, by determining the ratio of free channels to busy channels. The parameter can also be determined by monitoring the likelihood and / or delay in which mobile stations manage to allocate resources, such as traffic channels. It is also possible to calculate the number of packets sent to the mobile station MS per unit of time and maintain the Liu-15 time average of this amount. Alternatively, it can be utilized that in most packet networks, packets are time-stamped when they arrive in the network, whereby a service status parameter can be determined based on, for example, downlink packet time stamps. Based on this timestamp, the two waterways TAVE and T95 (or one of them) described in Table 1 can be determined. This calculation may take place, for example, at the base node SGSN, at the base station controller BSC, or at the base station BTS.

If the parameter describing the service situation is determined in a fixed network element of the network, such as a base station system BSS or a support node SGSN, this parameter can be transmitted to the terminal (MS, PC) on a broadcast channel. In the GPRS ice system, suitable channels are, for example, BCCH or PBCCH. Alternatively, this parameter may be transmitted to the terminal (MS, PC) as a multicast, such as a Point-To-Multipoint transmission. Instead of multicasting, the parameter can be sent to one terminal (MS, PC) at a time, for example, in a GPRS system, as a Point-To-30 or as a short message. The multicast and the individual transmission may be combined so that the parameter is sent to the terminals generally as multicast, but individually to the terminal logged in to the network, for example as a Point-to-Point transmission or as a short message.

In order for the terminal user or the application program 35 running therein to make objective decisions about changing the service class, it is ·· advantageous that said parameter is defined in more than one service class. If the parameters are transmitted to all terminals at the same time (for example, broadcast or multicast), it is most advantageous to transmit the parameters describing the situation of all service classes at the same time. If, on the other hand, the parameters are transmitted to the terminals individually, the capacity 5 can be saved by transmitting only the service class parameters used to describe the situation of the upper and lower service classes.

Conventional cell or handover algorithms are generally based only on signal quality. However, there may be situations where the neighboring base station serving the mobile station would have more capacity and could provide a faster connection than the base station currently serving the mobile station. In this case, it is advantageous for the service status parameter to be defined for at least two base stations (the mobile serving base station and the best-neighbor neighbor base station), and the parameter is utilized as a handover criterion. One possibility to utilize base station capacity-15 as a handover criterion is to emphasize signal strength measurements such that a higher signal strength is reported to the base station having a large amount of unused capacity, and vice versa. In this way, changes to known cell exchange algorithms are minimal.

Once information on the service status of the service classes is made available to the terminal (either by computing a parameter describing the service in the terminal or by computing the information on the network and sending it to the mobile station), this information must be made available to the application program and / or Service application information about service classes can be utilized in the application program, for example, by having predefined criteria for the application based on which the application negotiates a service class higher or lower if the service status parameter is lower or correspondingly greater than a predetermined threshold. Here, it is also advantageous to define a particular hysteresis, for example, by negotiating a higher (faster) service class if the parameter is below the threshold by 10% and by negotiating a lower (cheaper) service class if the parameter exceeds the threshold by 10%. Instead of or in addition to hysteresis, a time delay can be defined, for example, so that the service class is renegotiated only if the parameter has been below or above the threshold for a certain time, such as one minute. However, in this case, a new service class can be negotiated immediately if there is a large deviation from the threshold value in the parameter 35 (for example ·· if the average path delay is twice the normal value). In this way, the terminal and the application program executed therein can independently, without disturbing the user, make decisions that maintain the level of service to cost at an optimal level.

In some cases, it should be possible to change the service class in a way 5 that is almost impossible to program in advance. For example, it is possible to imagine a situation where a user uses a mobile device (and a computer connected to it or integrated) to handle banking while waiting for an aircraft to depart. When the departure of an airplane is announced, the user is likely to be prepared to pay for the upgrading of the service even in order to complete his banking 10. The reverse example may be a user who wants to initiate data transfer using a high service class (to allow the interactive phase to occur as quickly as possible), but the data transfer itself may be slow, in a less expensive service class. In order for the user of the terminal to decide whether to change the service category, the pa-15 parameter describing the service situation must be informed to the user. The service situation may be communicated to the user, for example, by a mobile service station MS and / or a PC PC display having an existing service status element (e.g., number, dot, or bar) whose feature (such as number value, size, color, or blink rate) By pointing this element at the cursor movement mechanism 20 (such as a keyboard, mouse, etc.), the user can initiate a dialog showing more detailed information and allowing the user to renegotiate the service class. When the service class switching is done automatically by negotiation between the application program and the network, it may be advantageous to produce a beep to allow the user to accept or reject the service class change proposed by the application program.

It will be obvious to one skilled in the art that as technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.

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Claims (15)

A method for detecting a current service situation in a packet radio network comprising at least one base station (BTS) and at least one terminal (MS, PC), wherein a plurality of service classes are defined; Characterized in that - at least one parameter describing the service status of the packet radio network is determined; and - making this parameter available to the terminal (MS, PC). Method according to claim 1, characterized in that said parameter is determined in a fixed network element of the network, such as a base station system (BSS) or a support node (SGSN). A method according to claim 1, characterized in that said parameter is determined in the terminal (MS, PC). Method according to claim 2 or 3, characterized in that said parameter is determined on the basis of the capacity utilization of the base station system (BSS). A method according to claim 2 or 3, characterized in that said parameter is determined based on the time slots of the downlink packets. Method according to claim 2 or 3, characterized in that said parameter is determined based on the probability of success of resource allocation attempts or the waiting time of resource allocation. 7. A method according to claim 2, characterized in that said parameter is transmitted to the terminal (MS, PC) via a broadcast channel, preferably a BCCH or a PBCCH. f A method according to claim 2, characterized in that said parameter is transmitted to the terminal (MS, PC) as a Point-To-Multipoint transmission. 8 104606 9. A method according to claim 2 or 8, characterized in that said parameter is transmitted to at least some of the terminals (MS, 9 104606 PC), preferably to the terminally logged-in terminal individually, such as a Point-to-Point transmission or a short message. A method according to claim 2, characterized in that said parameter is defined in more than one service class. A method according to claim 2, characterized in that said parameter is determined in all service classes of the packet radio network. A method according to claim 1, characterized in that said parameter is determined for at least two base station systems (BSS) and used as a handover criterion. Method according to one of Claims 1 to 12, characterized in that said parameter is communicated to the user of the terminal (MS, PC). A method according to any one of claims 1 to 12, characterized in that said parameter is passed to an application program executed in the terminal (MS, PC). A method according to claim 14, characterized in that at least one setpoint is defined for said application program and the application program negotiates independently a new service class if said parameter deviates substantially from said setpoint. «>« 9 »m · 104606 10