10 Handovers with Optimizations Between 3GPP Accesses and Mobile WiMAX

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

10.1 Optimizations for network-controlled dual radio handover

10.1.1 General Principles

The solution for network-controlled dual radio handover between 3GPP accesses (GERAN, UTRAN, E-UTRAN) and Mobile WiMAX is based on the concepts of clause 4.1.2 In addition, the following principles apply when the ANDSF functionality is supported by the network and by the UE:

1) The EPS shall support mechanisms for delivery of inter-system mobility policies and access network discovery information over the S14 interface, as described in clause 4.8.

2) The inter-system mobility policies shall contain operator-defined rules and preferences that help the UE:

(i) determine when mobility between mobile WiMAX and 3GPP accesses is restricted or allowed; and

(ii) determine when a 3GPP or mobile WiMAX access is more preferable than the currently used radio access.

3) The access network discovery information shall contain information about mobile WiMAX access networks that are available in the vicinity of the UE, if the UE’s location is known and if such information is available in the network and allowed by the operator.

4) If a UE discovers a neighbour mobile WiMAX access and determines (based on the inter-system mobility policies and user preferences) that:

(i) the discovered mobile WiMAX access is more preferable to the currently used 3GPP access; and

(ii) mobility from 3GPP access to mobile WiMAX access is allowed, then the UE shall attempt to handover to the discovered mobile WiMAX access;

according to the S2a/S2c procedures described in clause 8.

5) If a UE discovers one or more neighbour 3GPP accesses and determines (based on the inter-system mobility policies and user preferences) that:

(i) 3GPP access is more preferable to mobile WiMAX access; and

(ii) mobility from mobile WiMAX access to 3GPP access is allowed, then the UE shall select a neighbour 3GPP access (e.g. based on 3GPP access selection rules) and shall attempt to handover to the selected 3GPP access;

according to procedures described in clause 8.