METHOD AND APPARATUS FOR LATE ENTRY IN ASYNCHRONOUS FREQUENCY HOPPING SYSTEMS USING RANDOM PERMUTATION SEQUENCES

摘要

A wireless method and apparatus for late entry in frequency hopping systems that, during call setup, computes a random permutation sequence through a hop set of frequencies, chooses preamble frequencies to omit data thereon in lieu of preamble data, and swaps frequencies in the random permutation sequence such that synchronization frequencies lie next to the preamble frequencies with an expected delay such that late entrants can join. The wireless method and apparatus meets the FCC requirement of maintaining a pseudorandom hopping pattern and equal distribution of all frequencies in a hop set while guaranteeing late entry and having no effect on battery performance of radios.

主权项

1. A method for late entry in asynchronous frequency hopping wireless communications, the method comprising:
generating a random permutation sequence of frequencies, 1 to N, in a hop set based on data exchanged in a connection establishment phase, wherein the hop set comprises N frequencies; finding a selected preamble frequency in the random permutation sequence; and switching a subsequent frequency in the random permutation sequence after the selected preamble frequency with a synchronization frequency, wherein the subsequent frequency is located where a late entrant expects to find the synchronization frequency containing a synchronization frame after detecting a preamble frame on the preamble frequency in the random permutation sequence.