Method and radio communication system for the transmission of useful information as a service to several user stations

The invention relates to a method for transmitting useful information in a radio communication system with at least one radio network control device, at least one base station, and at least one subscriber station according to the preamble of claim 1.

The invention also relates to a radio communication system according to the preamble of claim 10.

Communication systems are becoming increasingly important. There are strong efforts to link wired communication systems with radio communication systems. The resulting hybrid communication systems lead to an increase in the number of available services, but also provide greater flexibility on the part of communication. In doing so, devices are developed that can use different systems (multi homing).

Due to the mobility of the participants, the radio communication systems are of great importance.

In radio communication systems, information (for example, voice, picture information, video information, SMS [short message service] or other data) is transmitted by means of electromagnetic waves via a radio interface between transmitting and receiving stations (base station or subscriber station). The electromagnetic waves are emitted at carrier frequencies, which lie in the frequency band provided for the respective system.

For the introduced GSM mobile system (Global System for Mobile Communication), frequencies are used at 900, 1800 and 1900 MHz. These systems essentially transmit SMS, Short Message Service (SMS) and digital data.

For future mobile radio systems with CDMA or TD / CDMA transmission methods, such as UMTS (Universal Mobile Telecommunication System) or other third-generation systems, frequencies in the frequency band of approximately 2000 MHz are provided. These third-generation systems are developed with the objectives of worldwide radio coverage, a wide range of data transmission services and, above all, flexible management of the radio interface capacity, which is the interface with the least resources in radio communication systems. In the case of these radio communication systems, the flexible management of the radio interface should make it possible for a subscriber station to send and / or receive a large amount of data at a high data rate.

The access of stations to the common radio resources of the transmission medium, such as, for example, time, frequency, power or space, is controlled by these multiple access methods (Multiple Access, MA) in these radio communication systems.

In time domain multiple access (TDMA) methods, each transmit and receive frequency band is divided into time slots, one or more cyclically repeated time slots being allocated to the stations. TDMA is used to separate the radio resource time station-specific.

In frequency domain multiple access (FDMA) methods, the entire frequency domain is divided into narrow band regions, with one or more narrow band frequency bands being allocated to the stations. FDMA separates the radio resource frequency station-specific.

In the case of code area multiple access methods (CDMA), the spreading code, which consists of many individual so-called chips, encodes the power / information to be transmitted station-specifically, whereby the power to be transmitted is randomly spread over a wide frequency range. The spreading codes used by different stations within a cell / base station are mutually orthogonal or substantially orthogonal, whereby a receiver recognizes the signal power that is thought of, and suppresses other signals. CDMA separates the radio resource resources by spreading codes station specific.

In the case of orthogonal frequency multiple access methods (OFDM), the data are transmitted broadband, the frequency band being divided into equidistant, orthogonal subcarriers so that the simultaneous phase shift of the subcarriers spans a two-dimensional data flow in the time-frequency range. By means of OFDM, the radio resource frequency is separated by means of orthogonal subcarriers station-specific. The summarized data symbols transmitted during a time unit on the orthogonal subcarriers are referred to as OFDM symbols.

The multiple access methods may be combined. Thus, many radio communication systems use a combination of TDMA and FDMA methods, each narrowband frequency band being divided into time slots.

For the aforementioned UMTS mobile radio system, a distinction is made between a so-called FDD (Frequency Division Duplex) mode and a TDD (Time Division Duplex) mode. The TDD mode is characterized in particular in that a common frequency band is used both for the signal transmission in the uplink direction (UL uplink) and in the downlink direction (DL downlink), whereas the FDD mode for the two transmission directions in each case has a different frequency band uses.

In radio communication connections of the second and / or third generation, information can be transmitted channel-switched (CS circuit switched) or packet switched (PS packet switched).

The connection between the at least one base station and the at least one subscriber station is made via a radio communication interface. The base station can thereby serve several radio cells.

Typically, the at least one base station and radio network controller (RNC) are components of a base station subsystem (RNS radio network subsystem). A radio communication system typically comprises a plurality of base station subsystems connected to a core network (CN core network). The radio network control device of the base station subsystem is connected to an access device (SGSN serving GPRS support node) of the core network.

In addition to individual user information, data transmission is made in radio communication systems, which are made available to several users. For example, such payloads include video streams or other broadcast and / or multicast information. The services for transmitting user information, which are not only provided individually for a single subscriber, but are made available to several subscribers, are combined under the term MBMS (Multimedia Broadcast / Multicast Service). Different MBMS services (multimedia broadcast / multicast service) are usually provided by the core network as separate data streams.

WO 02/19741 A2 discloses a communication system in which an IP multicast is transmitted to a plurality of devices in an IP network. In order to provide, on the network side, information on which terminals want to receive which IP multicast, a member request is periodically sent to the terminals (end device membership query) on the network side. Upon receipt of a membership request, a terminal sends in response a membership report to a local router and identifies in the membership account those multicast groups the terminal desires to receive.

In 3GPP (3rd Generation Partnership Project), TS 22.146 V5.2.0 Release 5 describes the requirements to be supported by a 3GPP system (Universal Terrestrial Radio Access Network) and GERAN [GSM EDGE Radio Access Network] Broadcast and multicast services (EDGE: enhanced data rates for GSM evolution).

Before the useful information is made available to several subscribers, the subscriber stations of the subscribers who want to use the service are informed of the actual transmission of the useful information of the service. This notification of the subscriber stations is necessary in order for the receivers to be configured. Depending on the mode in which the subscriber stations are located (eg, "connected mode" or "idle mode"), the notification is made, for example, in the form of a "notification" or a "paging". Typically, group-specific mechanisms are used for notification, in which several subscriber stations are addressed at the same time.

The transmission of broadcast / multicast information as services should be advantageous. In particular, an avoidable allocation of radio resources should be avoided if possible.

It is therefore the object of the invention to provide a method and a radio communication system of the type mentioned in the introduction which meet these requirements.

The object is achieved for the method with the features of claim 1 and for the radio communication system with the features of claim 10.

Advantageous refinements and refinements are the subject matter of the dependent claims.

According to the invention, the notification to the subscriber stations of the subscribers at least partially includes a request for a response, and the transmission of the payload information takes place at least partially upon receipt of the response.

The invention assumes that as a rule the subscriber stations of participants using MBMS services are not distributed evenly in the radio network. Therefore, there will usually also be areas in the radio network, in which a transmission of the useful information of the MBMS services is superfluous, because a useful subscriber is not present there. Thus, if no response is received on a request to a response as part of a notification to the subscriber stations of the subscribers of an MBMS service on the network side, the transmission of the payload information is partially omitted. In this way, radio resources are not unnecessarily used.

The invention makes use of the fact that subscriber stations of the subscribers using the MBMS service do not have to be present in all radio cells of the radio communication system. Therefore, an unnecessary transmission of useful information in the radio cells or sectors of radio cells can be avoided, where no corresponding response was made after a request to the subscriber stations.

Advantageously, a grouping of the subscriber stations into groups with regard to the notification takes place. In particular, an identical notification can be sent to a group of subscriber stations of the subscribers. Due to the already existing radio network architecture, it is particularly favorable if the grouping of the subscriber stations is carried out by means of their allocation to radio cells. The invention can then be inserted particularly easily into existing systems.

According to the invention, the notification to the subscriber stations of the subscriber, as stated above, at least partially includes a request for a response, ie at least some subscriber stations or one or more groups of subscriber stations receive a request for a response. In an embodiment of the invention, the notification to the subscriber stations of the subscriber comprises either a request for a response or an information that no response is required, in which case the transmission of the useful information takes place independently of a response.

For example, in radio cells which supply a hot spot, a request for an answer is dispensed with, since, because of the, for example, high density or large number of subscriber stations, it is highly probable that at least one subscriber using the offered MBMS service is present. By not requesting a response in this case, not only radio resources are saved but also unnecessary delays in the transmission of MBMS services can be avoided. Overloading situations can be effectively avoided when accessing shared resources in the uplink, for example, in the case of a large number of subscribers using MBMS services in a radio cell, which would happen just then,

The subscriber stations or the groups of the subscriber stations are notified in the notification via an appropriate infromation area, or are supposed to make an answer or not. The request for a response (RESP) or the information that no response is required can be transmitted in the form of a bit (eg "response" bit).

In a further development of the invention, depending on at least one decision criterion, a determination is made as to whether a notification with a request for a response or with the information that no response is required is transmitted by the radio network control device to the groups of subscriber stations of the subscribers. The fixing is preferably effected in the radio network control device.

In principle, a static and / or a dynamic, but in any case, a funcet network-specific decision criterion can be used. The decision as to whether or not notification with a request for a response or with the information that no response is required can be appropriately adapted to the static and dynamic conditions, for example, in a radio cell.

The decision criterion can be, for example, the configuration of the radio network, the knowledge of the subscriber, the utilization of the radio resources (eg a large number of subscribers using the shared resource in the uplink) in the radio network or in areas thereof Duration of the transfer) or a combination of the abovementioned possibilities. Information on the configuration can be provided by the OMC Operation and Maintanance Center, for example.

In an embodiment of the invention, the responses of the subscriber stations of the subscribers who have been requested to respond, in particular the responses of the subscriber stations within a group of subscriber stations, are not transmitted at the same time. This measure also contributes effectively to a temporally distributed use of radio resources.

The responses of the subscriber stations of the subscribers who have been asked for a response, in particular the responses of the subscriber stations of a group, can be transmitted randomly or preferably in a controlled manner with regard to the time of transmission.

Advantageously, the transmission of the useful information for a group can be carried out after receipt of the response from at least one subscriber station of the group. This prevents delays and saves radio resources. In connection with the request of time-spread responses of the subscriber stations, the subscriber stations, which want to transmit their response after the receipt of a response of a first subscriber station, are, for example, informed at the beginning of the transmission of the payload information of the service or, Payload information from the service detects that an answer is no longer required.

In the radio communication system according to the invention, means are provided, so that the notification to the subscriber stations of the subscribers at least partially comprises a request for a response, and that at least the transmission of the payload information takes place after receipt of the response.

The radio communication system may have means for sending notification to groups of subscriber stations of the subscribers.

Means can be provided for determining, depending on at least one decision criterion, whether a notification with a request for a response or with the information that no response is required is transmitted by the radio network controller to a group of subscriber stations of the subscribers. These means are preferably located in the radio network control unit (RNC). The radio network control device is then expanded, for example, by a function which evaluates whether, for example, a response is to be requested or not because of the specific configuration of a radio cell.

The described radio communication system is particularly suitable for carrying out the method according to the invention. In the radio communication system or its individual components, respective means and means for carrying out the method and its configurations and further developments can be provided.

The invention is to be explained in more detail below with reference to exemplary embodiments and two figures.

Here,<dl id="dl0001"><dt>FIG. 1:</dt><dd>A schematic representation of a radio communication network according to the invention,</dd><dt>FIG. 2:</dt><dd>2 shows a schematic diagram of a flow chart for the transmission according to the invention between core network, radio network control device, base station and subscriber station.</dd></dl>

FIG. 1 shows a schematic representation of a radio communication network for a transmission according to the invention between a radio network control device RNC, two base stations NodeB1 and NodeB2 and mobile subscriber stations UE1, UE2, UE3, UE4, UE5 and UE6.

The radio network control device RNC is connected, on the one hand, to an access device of a core network CN and, on the other hand, to the two base stations NodeB1 and NodeB2. Base station NodeB1 serves the radio cells A and B and base stations NodeB2 the radio cells C and D. In the radio cell B are the subscriber stations UE1 and UE2. The subscriber stations UE3, UE4, UE5 and UE6 are assigned to the radio cell C.

In the radio cell B of the base station NodeB1, an MBMS service, which can be signaled, for example via a group control channel from the radio network control unit RNC via the radio cell B via the radio communication interface, is to be received by the mobile subscriber station UE2. The notification in the radio cell B includes a request for a response. UE1 is currently not interested in using an MBMS service. After the subscriber stations UE2 has replied to the request in the notification by sending a reply, the service cell B starts the transfer of the useful information of the service. The useful information of the service is transmitted, for example, via a traffic channel.

An MBMS service is also to be transmitted in the radio cell C. For example, radio cell C supplies a potential hotspot. On the basis of this knowledge, a call to a response within the radio cell C is dispensed with in the radio network monitoring device RNC, as a larger number of users of the MBMS service are expected here. Without delay, therefore, useful information of the MBMS service is transmitted in the radio cell C to the base station NodeB2 via the radio communication interface, and the mobile subscriber stations UE3, UE4, UE5 and UE6 are grouped by the subscriber stations by their assignment to the radio cells.

No subscriber stations are shown in radio cells A and D.

FIG. 2 shows a schematic representation of a flow diagram for the transmission according to the invention between core network CN, radio network control unit RNC, base station NodeB and subscriber station UEn.

Via an access device of the core network CN, the radio network control device RNC receives the message NOTIF-1 that user information of an MBMS service is to be provided to subscriber stations UEn.

1, the MBMS service is to be made available to the subscriber station UE2 in the radio cell B of the NodeB1 and the subscriber stations UE3, UE4, UE5 and UE6 in the radio cell C of the NodeB2 of FIG. 1, with reference to the exemplary embodiment described in connection with FIG . The radio network control unit RNC thereby makes the decision DECIS that the notification NOTIF-2 to the subscriber station UE2 contains a request for a response RESP and the notification NOTIF-2 to the subscriber station UE3 to UE6 comprises information that no response is required. In the radio cell B of the base station NodeB1, a transmission of the useful information of the MBMS service ensues after the response RESP is received.