Enhanced Mobility Management Scheme in PMIP-SAE-Based Mobile Networks

In the existing PMIP scheme for SAE-based mobile networks such as LTE, data delivery is performed by GTP between eNB and S-GW, and also between eNBs in X2-based handover, while GRE protocol is used between S-GW and P-GW. However, the use of GTP tunnels between eNB and S-GW and between eNBs tends to induce large tunneling overhead for packets. Existing scheme also tends to incur large registration delay and route update delay after handover. To overcome the drawbacks, we propose an enhanced mobility management scheme for SAE based mobile networks. In the proposed scheme, we combine two user plane nodes, S-GW, and P-GW, as a single entity, and make it function as LMA. Further, each eNB works as a MAG of PMIP. The GRE tunnel is used between eNB/MAG and S-GW/P-GW/LMA, and also between eNB/MAGs, instead of GTP. Differently from the existing scheme, target eNB/MAG exchanges PBU and PBA messages directly with the S-GW/P-GW/LMA in the route update operation after handover, not through MME. Numerical analysis shows that the proposed scheme reduces all the tunneling overhead, registration delay, and route update delay after handover significantly.