Automatic Recovery of Ciphering Parameter Synchronization

Li-Wen WU

IEICE TRANSACTIONS on Communications   Vol.E88-B    No.10    pp.4008-4012
Publication Date: 2005/10/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.10.4008
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
data ciphering,  hyper frame number (HFN) synchronization,  unacknowledged mode (UM) transmission,  length indicator,  

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In this paper, we briefly describe situations that may cause HFN de-synchronization for ciphering applications in UMTS. Detection methods of HFN de-synchronization are discussed and the lower bound of the HFN de-synchronization perceptibility is derived. A supporting simulation result of the perceptibility is given. Then, an Automatic Recovery of HFN Synchronization (ARHS) algorithm is presented. The average lost PDU number of the ARHS algorithm is derived and supported by simulation results. The average lost SDU number is used as the figure of merit for HFN synchronization recovery procedures. Simulation results of the average lost SDU number show that the ARHS algorithm is quite effective to recover HFN synchronization after HFN de-synchronization situations happen.