System and method for channel probability mass function dependent frequency hopping
A system and method for generating a channel statistics dependent frequency hopping pattern that requires low computational complexity and simultaneously maximizes channel capacity and minimizes the symbol error rate or bit error rate under partial band tone interference and Rician or other fading environments. The system includes one or more transmitting units and one or more receiving units communicating over a wireless communication network. A signal generated at one of the transmitting units is modified via the channel statistics dependent frequency hopping pattern as generated via one of the receiving units for improved signal accuracy and avoiding interferer detection and/or interference hits.
1. A method of transmitting data over a wireless communication network, the method comprising the steps of:
generating a signal divided into epoch time intervals and further divided into time hop intervals;
performing a compromised measurement at each of said time hop intervals of one of said epoch time intervals;
determining an interference probability mass function by counting a number of compromised time hops at the one of said epoch time intervals;
determining a signal probability mass function having a small inner product between said signal and said interference probability mass function;
applying an inverse method to said interference probability mass function to find said signal probability mass function;
generating a hopping sequence by determining a number of time hops to be used during said epoch time interval at each hopping frequency, the time hops being determined by multiplying said epoch time length to the probability at each hopping frequency of said signal probability mass function, wherein the hopping sequence is a core typical sequence;
permuting said core typical sequence;
generating a frequency hopping pattern according to the permuted core typical sequence;
defining a pool of all frequency hopping pattern candidates via said signal probability mass function and an information theory based typical sequence;
selecting a subsequent frequency hopping pattern from the pool of frequency hopping pattern candidates such that said subsequent frequency hopping pattern is adaptively dependent upon said interference probability mass function spanning over said plurality of signal frequencies;
incorporating said subsequent frequency hopping pattern into said signal; and
transmitting the signal.
2. The method of claim 1 , wherein the signal is received by a receiving unit and the subsequent frequency hopping patterns are generated by the receiving unit via the generated frequency hopping pattern index information upon receiving the signal.
3. The method of claim 1 , wherein the step of determining an interference frequency hopping probability mass function includes the steps of:
measuring a signal-to-noise ratio at each time hop and at each frequency; and
if the measured signal-to-noise ratio is lower than a predetermined threshold, count the current time hop as being compromise,
wherein an interference frequency hopping probability mass function value at a given frequency during a current epoch time interval is the ratio of the number of compromised hops over the total number of hops at the given frequency in the current epoch time interval.
4. The method of claim 1 , wherein groups of time hops comprise an epoch time interval, and the step of determining an interference frequency hopping probability mass function includes the step of counting a number of time hops compromised at each signal frequency.
5. The method of claim 3 , wherein the step of measuring a signal-to-noise ratio is measured at the end of each time hop, and the value of said interference frequency hopping probability mass function at each frequency for each epoch interval is measured at the end of each epoch time interval.
6. The method of claim 4 , wherein the step of determining an interference frequency hopping probability mass function is performed for an individual epoch time interval.
7. The method of claim 4 , wherein the step of determining an interference frequency hopping probability mass function is performed over a number of epoch time intervals.