BRIEF DESCRIPTION OF THE DRAWINGS
Some methods and embodiments of the present invention will now be described by way of example only, and with reference to the accompanying drawings, in which:
FIG. 1 schematically illustrates E-UTRAN architecture;
FIG. 2 schematically illustrates messaging associated with an E-UTRAN system;
FIGS. 3 and 4 schematically illustrate a method and E-UTRAN system in accordance with the invention;
FIG. 5 schematically illustrates messaging associated with an E-UTRAN system in accordance with the invention; and
FIGS. 6 to 9 schematically illustrate alternatives.
DETAILED DESCRIPTION OF THE DRAWINGS
With reference to FIGS. 3 and 4, a UE 6 includes a store 9 in which are stored preset values relating to the Quality of Service, Medium Access Control, (MAC), and Radio Link Control (RLC). Similarly, an eNB 8 has a store 9 that stores preset values for the same parameters. The aGW stores the security context.
When the UE 6 wishes to connect to a core network, represented by an aGW 10, certain initial signaling takes place, as shown at 11 on FIG. 4 to alert the eNB 8 and enable a signaling connection to be set up between the UE and eNB. Following this, both the UE 6 and the eNB 8 separately and independently access their stored values held at stores 7 and 9 respectively as shown at 12 and 13 to enable an RB to be established between them, this RB being an Early RB.
In addition the S1 transport bearer between the eNB 8 and the aGW 10 is configured. In this method, the required data is already stored at the aGW 10, as stored preset values. The data stored in the eNB does not include user specific information like the TEID to be used for each RB. User data is transmitted between the UE 6 and eNB 8, and between the eNB 8 and the aGW 10, as shown at 14.
Following the Early RB establishment, modification is required to the RB parameters to the more specific RB conditions most appropriate for that data flow, available once the messaging is complete to enable such an RB to be formally established.
FIG. 5 illustrates the messaging associated with the arrangement illustrated in FIG. 4, with Steps being given the same numbering as that shown in FIG. 2. It can be seen from this that the order of the steps is now different, for example Step 10 occurs after Steps 15 and 16. By deferring some of the steps relative to others, overall delays in the system may be reduced compared to the FIG. 2 message flow.
Data packets sent on the early radio bearer are encrypted with encryption including a sequence number associated with a data packet. The sequence number is also used to discard duplicated packets.
Several alternative solutions to identify the RB of the packet are shown in FIGS. 6 to 9. An alternative to the Early establishment of the S1 interface is shown in FIG. 6. In this case, packets are buffered in the eNB until the UE context response from the aGW 10 is received.
FIG. 7 illustrates another approach to identify the RB that the packet belong to, in which an additional header element is used to identify the logical channel in addition to the Tunnel Endpoint Identifier (TEID) over the eNB to aGW S1 interface.
FIG. 8 shows another method, in which special values of TEID are preconfigured to identify the logical channel exclusively for the Early data bearer. This is a temporary assignment and released as soon as the proper bearer is established. Thus, only a small number of preconfigured values are required. The TEID is subsequently reconfigured to the correct one to identify the logical channel of the real bear established subsequently.
Finally, in FIG. 9, another method is such that the logical channel Id is included in the PDCP header provided by the UE.
The present invention may be embodied in other specific forms, and implemented by other methods, without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Patent Application
20080051084
