3GPP TSG-T3 (USIM) Meeting #9
Kyongju, Korea, October 4 - 6, 1999	Tdoc T3-99276	

TSG-RAN Working Group 2 (Radio layer 2 and Radio layer 3) 	TSGR2#6(99)984
Sophia Antipolis, France, 16 - 20 August 1999	

Title:		LS to S2 cc T3, S3 on parameters to be stored in the USIM

From:		TSG RAN2

To:		TSG S2 

Cc:		TSG T3, TSG S3
	
TSG RAN2 would like to thank TSG SA2 for requesting information about network related parameters to be stored in the USIM.

For the time being, RAN2 has identified the following information that is relevant for the Access Stratum to store in the USIM. Information, that is handled by the Non-Access Stratum is not considered here (e.g., information on PLMNs). 

1.	Ciphering information
-	Ciphering keys
Kc-CS for the circuit switched domain and Kc-PS for the packet switched domain
-	Hyper Frame Number (HFN)
HFN is part of the Ciphering Sequence Number (CSN) [TS 25.301 V3.1.0] which is now COUNT in the SA3 specifications.
"The Hyper Frame Number (HFN) is initialised by the UE and signalled to the SRNC before ciphering is started. It is used as initial value for each ciphering sequence, and it is then incremented independently in each ciphering sequence, at each cycle of the ‘short’ sequence number. When a new RAB / logical channel is created during a RRC connection, the highest HFN value currently in use is incremented, and used as initial value for the ciphering sequence of this new logical channel. The highest HFN value used during a RRC connection (by any ciphering sequence) is stored in the USIM, and the UE initialises the new HFN for the next session with a higher number than the stored one. If no HFN value is available in USIM, the UE randomly selects a HFN value." [TS 25.301 V3.1.0]

2.	Frequency information
-	List of frequencies 
Stored carrier frequency information is needed for optimisation of the cell selection procedure. The exact number of the stored frequencies is FFS.
-	Scrambling codes
Stored scrambling code information is possibly needed for the cell selection procedure. The need of storing the scrambling code information and the exact number of the codes are FFS.