Local IP Access and IP Traffic Offload for Femtocells

3GPP has enhanced Local IP Access and IP Traffic Offload for femtocells in Release 10. Rel 9 only focused on Local IP Access to the home based network only while Rel 10 extends same to enterprise IP network as well.

LIPA (Local IP Access) provides access for IP capable UEs connected via a H(e)NB (i.e. using H(e)NB radio access) to other IP capable entities in the same residential/enterprise IP network.

Traffic for Local IP Access is expected to not traverse the mobile operator’s network except H(e)NB.

With Selected IP Traffic Offload (SIPTO), H(e)NB would support Selected IP Traffic Offload to provide access for a UE connected via a H(e)NB to a IP network e.g. Internet.

In 3GPP Rel-8 and Rel-9, 3GPP has specified functionalities for the support of H(e)NB. 3GPP had requirements on Local IP Access to the home and Internet in TS 22.220 but those features were not completed as part of Release 9.

3GPP Rel 10 extends LIPA requirements for H(e)NBs as followings, some of them already has been identified by Rel 9.

• Support of Local IP Access in order to provide access for IP capable UEs connected via a H(e)NB to other IP capable entities in the same residential/enterprise IP network.
• Support of simultaneous access from a UE to the mobile operator’s core network and Local IP Access to a residential/enterprise IP network
• Local IP Access traffic to be routable only between the UE, H(e)NB and other entities within the residential/enterprise IP network (subject to regulatory requirements).
• UE to have a valid subscription with the mobile operator in order to use Local IP Access.
• Use of Local IP Access in a visited network by UE to be subject to roaming agreement between mobile operators.
• The HPLMN to be able to enable/disable LIPA usage when the UE roams to particular VPLMNs.
• Local IP Access to be available for Pre-Rel 10 UEs as well.
• A UE using LIPA will be contactable by another IP endpoint in the same IP network via Local IP Access.
• UE to maintain its IP connectivity to the residential/enterprise IP network when moving between H(e)NBs within the same residential/enterprise IP network.
• The mobile operator can enable/disable Local IP Access per H(e)NB and per UE.
• Local IP Access will not compromise the security of the mobile operator’s network.

Selected IP Traffic Offload (SIPTO) for H(e)NB

H(e)NB can support Selected IP Traffic Offload to provide access for a UE connected via a H(e)NB to Internet. The following 3GPP requirements apply to support Selected IP Traffic Offload for H(e)NB SubSystem:

• Selected IP Traffic Offload to be possible to be done without traversing the mobile operator network, subject to regulatory requirements.
• The mobile operator and the H(e)NB Hosting Party, within the limits set by the mobile operator, shall be able to enable/disable Selected IP Traffic Offload per H(e)NB.
• Based on mobile operator SIPTO policies, the network shall be able to allow the user to accept/decline offload before the traffic is offloaded.
• The SIPTO policies may be defined per APN, per IP Flow class under any APN, or per IP Flow class under a specific APN.
• The mobile operator shall be able to configure the SIPTO policies either statically or dynamically.

HNBs in Enterprise Environments

HNBs are expected to be used in enterprises for business communication among permitted users. To allow easy integration into the enterprise's IT infrastructure, HNB needs to support additional functions e.g. Authentication and charging.

IP enabled UEs that are connected via HNBs to the enterprise IP network are expected to receive the enterprise's IP based services.

The following additional requirements apply for intended usage of HNBs in enterprise environments.

HNB may be able to route traffic to/from the enterprise's IP network without traversing the mobile operator’s core network, subject to regulatory requirements and agreement between the Mobile Operator and the Enterprise.

Local traffic routing applies to:

• Traffic between the UE and another UE under coverage of the enterprise's HNBs
• Traffic between the UE and entities in the enterprise IP network (e.g. when interworking with an IP- Private Branch Exchange (IP-PBX))

According to 3GPP specification, it may be possible to support interworking with an enterprise's existing voice and multimedia services (e.g., (IP-PBX). In particular UEs under coverage of the enterprise's HNBs may be able to participate in interactive communication services offered by the IP-PBX.

Source: LteWorld