Patent ID: 8583042

Claim:
A terminal for a communication system, comprising: a transmitter configured to send scan request messages through a plurality of communication channels according to a respective channel sequence that specifies a succession of time intervals and a respective communication channel to be used during each interval, wherein the plurality of communication channels of the channel sequence are randomized with respect to the intervals that are respective to the terminal by: (a) randomly or pseudo-randomly independently determining the respective communication channel to be used in each interval; or (b) dividing the succession of intervals into successive blocks that each include a plurality of successive intervals and randomly or pseudo-randomly determining the channels to be used in each block, with each channel in a block to be used only once in that block and each block independent of the other blocks; or (c) dividing the succession of intervals into successive blocks that each include a plurality of successive intervals and randomly or pseudo-randomly determining the channels to be used in each block, with each channel in a block to be used only once in that block and with different channels to be used in adjacent intervals in adjacent blocks; wherein step (c) includes computing, for each successive block k, a seqID k value according to: seqID k =mod(baseSeqID k-1 +rand{0, . . . , ( n− 1)·( n− 1)!−1} k , n !) in which n is a total number of channels, mod (.,.) represents a modulo function, rand{.} represents a randomization function, .! represents factorial, baseSeqID k-1 is a completeness parameter, the channels are respectively numbered 1, 2, . . . , n, and seqID 0 =rand{0, . . . , n!−1}; and retrieving for each successive block k a stored channel sequence corresponding to the seqID k value.