Layered Call Admission Policy for 3G Cellular Data Networks: A CDMA2000 Case Study

Since IP networks are networks of choice due to their widespread footprint, cellular networks like CDMA2000 Packet Data Networks use them as their data network backbone. However, the IP networks are prone to discrepancies like routing loops that might cause service degradation and sometimes end-toend path failures. In CDMA2000 Packet Data Networks, existence of loops between different routers in the core IP network due to accidental or deliberate misconfigurations result in repeated retransmissions of packets of same ID across the network. Consequence of these retransmissions is more bandwidth consumption and degradation in overall network throughput. Moreover, Mobile Stations remain in transmission mode longer than they actual need, consequently more battery power is consumed and average cost per communicated data packet increases. Existing physical layer Call Admission Policies accept and sustain data calls despite core IP network is unable to entertain these calls. We propose a novel Call Admission Policy for 3G cellular data networks in general and CDMA2000 Packet Data Networks in particular that detects the existence of routing loop through Multi-Layer Call Admission Architecture implemented on PDSN and promptly drops the data calls experiencing routing loops. Admission of new data calls associated to misconfigured HA or core network router is blocked to increase network throughput and reduce unnecessary bandwidth utilization. In addition, significant decrease in average cost per data packet and battery power consumption will result as a consequence of reduced retransmissions.