Method for protected radio signal transmission
First Claim
1. In a method for protected transmission of digital signals by way of radio connection in which the signals are transmitted in blocks and in correspondence with the frequency hopping principle in which block-by-block transmission occurs on the basis of pseudo-randomly changing radio carrier frequencies, and in which the successive signal blocks are provided with error protection, and in which synchronization between a transmitting station and a receiving station is provided by quartz clocks at the stations, the improvement therein comprising the steps of:
- regenerating each received signal block;
checking each regenerated signal block as to its correct phase with respect to a reference phase to determine the block clock pulse phase and correcting the phase of a block in response to a determined phase difference for accurate processing of the signal block;
performing an error check of each signal block and correcting any perceived error for at least three successive phases at an interval of one bit; and
selecting for further processing that signal block which exhibits the smallest error number which still lies within a predetermined error tolerance range.
2 Assignments
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Accused Products
Abstract
In radio operation in tactical use, an increased jamming resistance with respect to intentional jamming is required. For protection against intentional jamming, frequency hopping techniques have proven very advantageous in which the signals are transmitted in the form of successive error-protected signal blocks where each signal block is transmitted on a different radio carrier frequency which changes in a pseudo-random manner. With this technique, phase shifts can occur which are greater than half a bit and therefore make analysis of the signal blocks difficult or impossible. It is proposed herein that each received signal block be checked after regeneration in a regenerative repeater, controlled by a bit clock pulse, as to its correct block phase and therefore, respectively, newly establish the block clock pulse phase required for further accurate processing of a signal block.
9 Citations
8 Claims
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1. In a method for protected transmission of digital signals by way of radio connection in which the signals are transmitted in blocks and in correspondence with the frequency hopping principle in which block-by-block transmission occurs on the basis of pseudo-randomly changing radio carrier frequencies, and in which the successive signal blocks are provided with error protection, and in which synchronization between a transmitting station and a receiving station is provided by quartz clocks at the stations, the improvement therein comprising the steps of:
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regenerating each received signal block; checking each regenerated signal block as to its correct phase with respect to a reference phase to determine the block clock pulse phase and correcting the phase of a block in response to a determined phase difference for accurate processing of the signal block; performing an error check of each signal block and correcting any perceived error for at least three successive phases at an interval of one bit; and selecting for further processing that signal block which exhibits the smallest error number which still lies within a predetermined error tolerance range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification