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UATI-IP address mapping

Peerapol Tinnakornsrisuphap (peerapol@qualcomm.com)David Ott (dott@qualcomm.com)

Qualcomm

October 28th, 2008

Recommendation: Discuss and adopt

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HRPD Idle Handoff from Femto -> Macro

• Reachability– Macro AN advertises different ColorCode from

Femto AP, so AT is triggered to register with macro AN

– Since AT only sends 8 bits ColorCode + 24 LSBs of UATI in access capsule, macro needs to be able to map these information into Femto AP IP address

– See next slide• Scalability

– See next slide• Additional Standardization Need

– IP address lookup scheme from CC:UATI24 to IP address of Femto and also to UATI128

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HRPD Idle Handoff from Femto -> Macro or Femto -> Femto : UATI, ColorCode and Subnet

• Number of users that can be supported in a Femto = 2C

• Number of Femtos that can be supported in a ColorCode = 224-C

• In order to resolve IP address of Femto, the following information are needed– Number of bits for C– Mapping from ColorCode to Subnet Mask in the geographical area– Mapping from BSC_ID to IP address of Femto

• BSC_ID maybe IP address of Femto, however, the private IP address assigned from operator to Femto cell in the same vicinity and same ColorCode needs to have same 8+C MSBs of IP address

• If two Femtos next to each other has same ColorCode, dormant handoff would not be triggered

– That might not be a problem. When connection is requested, the target Femto can still request session from source Femto. This eliminates need to constantly request UATI from Femto

– Need A13-Paging support between Femtos

AT-specificBSC_ID_LSBBSC_ID_MSB

Subnet Mask 104 bits (maps to 8 bits ColorCode)

C bits24-C bits

UATI128

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DO Idle Hand-out Design

• Alternative 2: DNS Registration– For each UATI that is not expired, Femto AP registers and

maintains DNS registration on UATI. The FQDNs that are registered by the Femto AP are in the following formats

• 1: <operator’s domain>.HRPD.RAN.subnet-<subnet>.uati32-<UATI32>– where <subnet> is the subnet of the macro AN– Note that AT cannot move in idle state from femto subnet to faraway macro

subnet without registering and transferring session to macro AN first

• 2: <operator’s domain>.HRPD.RAN.UATI104-<UATI104>.uati24-<UATI24>

– In case of power-down AT, prior session retrieval will be used (e.g., using full UATI128)

– DNS servers can be hierarchical, e.g., one DNS server per macro subnet