Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
2002-05-10
2004-01-27
Trost, William (Department: 2683)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
Reexamination Certificate
active
06684081
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the transmission of multicast and broadcast information between at least one mobile station and a controller of a wireless network.
2. Description of the Prior Art
Work to standardize multimedia broadcast multicast service (MBMS) as a new bearer to point to multipoint service has started in the third generation partnership project (3GPP). The aim of this work is to introduce new capabilities not only in Universal Terrestrial Radio Access Network (UTRAN) but also in the core network (CN) so as to provide point-to-multipoint services which use common network resources but which are intended to a restricted group of people (subscribers or users) in a cell. These requirements are not fully completed in the current cell broadcast concepts of 3GPP which is already standardized in 3GPP release 99 which is incorporated herein by reference in its entirety.
Even though standardization work in radio access network (RAN) working groups has not been fully started, some basic principles between RAN working groups and service architecture (SA) working groups have already been agreed. One such agreement includes that there is a no need for a retransmission functionality for multicast services which has been seen as not a feasible requirement from the UTRAN point of view. In practice, this means that the Radio Link Control layer (RLC) in UTRAN will support an unacknowledged mode (UM) or even transparent mode (TM) which does not require any previous information about the upper layer packet sizes which are used during the active multicast transmission of data through the air interface.
Another clear requirement from the UTRAN point of view is transmission of multicast related control and announcement information to and from the network to and from the mobile stations. In practice this means that, if transmission of control information is tied with the transmission of multicast data, i.e. through the same air physical channel, the multicast or broadcast concept used In UTRAN must be capable of separating the control information (i.e. control plane) and the multicast data (i.e. user plane) from each other. Due to the nature of multicast service transmission, when control information is sent to the air interface without knowledge regarding the current state of the authorized mobile stations, the control information (e.g. announcement frames) may have to be repeated without changing the content of the frame by changing the sequence number SN of the RLC Packet Data Unit (PDU). In this case, a comparison between an old and a new control frames cannot be made from the sequence number and therefore, something is required to recognize the reception of the already received control frames.
Broadcast and multicast transmissions are well-known. Broadcast transmissions are sent to mobile stations, whose identification and location are unknown as the result of, for example, no joining procedure having been completed. Multicast transmissions, on the other hand, are transmitted to only those subscribers that have previously indicated an interest in receiving the multicast services from the network, who can be identified after performance of the multicast joining procedure and/or whose location can be determined by tracking procedures.
In order to establish if subscribers or users, who control the mobile stations, are willing to receive a service providing a multicast or restricted broadcast transmission, two phases are executed. The first phase is the service registration phase during which subscribers or users, who possess the mobile stations, agree with the a service provider or operator, who controls the core network or the external network connected thereto, to receive the multicast or restricted broadcast services. The second phase is the multicast joining or subscription phase during which the subscribers or users, who possess the mobile stations, indicate a willingness to the service provider to receive the multicast or restricted broadcast services in order to obtain currently defined service configuration parameters of the multicast or restricted broadcast services. If the current service parameters have already been given to the mobile stations during the registration phase, the user of the mobile stations indicates a readiness to receive multicast or restricted broadcast services which enables the wireless network and the external network to make routing and resource management decisions which involve point to multipoint connections, such as a connection between the core network and the mobile stations regarding the offered service.
The most significant event of the above-described registration and multicast joining or subscription phase is the indication by the subscriber or user of the mobile stations of a willingness to receive an ordered multicast or restricted broadcast service from the service provider controlling the external network or network connected thereto. Subscription, which is required for the broadcast services (i.e. broadcast service, which are meant only to a restricted group of people), is always non-time critical (i.e. it can be made e.g. hours before the reception of the broadcast service, whereas the joining phase can be time critical (i.e., it is made just before the multicast transmission of the particular service is started) or a non-time critical transaction (i.e., the joining phase can be completed before the actual service activation). Depending on whether the joining transaction is a time-critical or a non-time critical transaction, services involving different subscriber service charges can be defined for the multicast or restricted broadcast service. This is a significant aspect of providing multicast or restricted broadcast services.
Currently, the 3GPP project has not specified a mechanism for separating multicast and broadcast related control plane (control information) from the user plane (user data).
SUMMARY OF THE INVENTION
The present invention provides a method and system which transmits control information and user data, relating to multicast or broadcast services, between a first information entity within at least one mobile station and a second information entity within a controller of a wireless network in which the at least one mobile station is located. The control information and user data is transmitted by using the same radio resources. Furthermore, the multicast and broadcast related control information and the user data may be transmitted during an active multicast or broadcast session. The mobile stations separate the already received control information from the first-time-received control information from each other. If the control information is such that it is repeated time after time, the mobile stations can decide to delete repeated packets at the RLC layer or whether to send the repeated packets to an upper layer. If the RLC sees that the packet is a duplicate of a previous one, the RLC layer can save the mobile station processing capacity and power by avoiding having to interpret the content of the packet.
Separation of the control information from the user data may be affected in any number of ways:
1. In one embodiment of the invention, the separation occurs at the RLC layer using two RLC entities and is made with two logical channels identified by corresponding values in Target Channel Type Field (TCTF) headers of data packets in the RLC layer. This embodiment does not require any changes to the existing PDU structure of the RLC and MAC layers in accordance with current standardization, such as 3GPP.
2. In a second embodiment of the invention the control information and the user data is also separated in the RLC layer using one RLC entity and two new logical channels. A length indicator is used in the header of the RLC layer to identify the type of logical channel to which the packets belong. No changes are required for the PDU structure in both the RLC and the MAC layers in accordance with current standardization such as 3GPP. This embodiment permits a
Koulakiotis Dimitris
Sarkkinen Sinikka
Antonelli Terry Stout & Kraus LLP
Le Danh C
Nokia Corporation
Trost William
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