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AssigneeMotorola, Inc.
InventorsRobert D. Logalbo, Alan Conrad, Darrell Stogner
Estimating the term…
Encryption synchronization (e-sync) is maintained between a transmitter (104) and one or more receivers (102) in a multi-modulation TDM system (100) where information is communicated in slots (402) comprising a slot header (404) and one or more data blocks (406), and wherein the data blocks are eligible to be encoded at different modulation rates thereby creating a likelihood of different numbers of blocks in different slots. The receiver and transmitter employ respective encryption elements (200, 300) comprising e-sync shifter elements (202, 302) and encryption algorithm blocks (204, 304). The e-sync shifter element provides an e-sync signal defining an encryption state vector to the encryption algorithm block and is operable to advance the encryption state vector (in the case of the receiver) according to a number of received bits plus a variable number of bits. The variable number depends on the number of bits within a block, the maximum number of blocks that could be within a slot and the actual number of blocks within the slot.
A method for a receiving device to maintain encryption synchronization in a multi-modulation TDM system whereby information is communicated in slots comprising a slot header and one or more data blocks, the data blocks each including a number of bits (NB) and being eligible to be encoded at different respective modulation rates thereby creating a likelihood of different numbers of blocks in different slots, the method comprising:
An encryption element comprising:
Dependencies are inferred from the claim text.