| CPC H04L 5/0048 (2013.01) [H04L 25/0202 (2013.01); H04L 27/10 (2013.01)] | 22 Claims | 

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               1. A method comprising: 
              receiving, by an apparatus from a network device, a first signaling indicating a length K sequence; 
                transmitting, by the apparatus to the network device a reference signal; 
                wherein the reference signal is obtained from the length K sequence, and the length K sequence is obtained by a cyclicly repeated length p ZC sequence, 
              where 
            p is a prime number, 
                p is larger than K/3, 
                a largest prime number that is smaller than K is greater than p, and 
                p is smaller than the largest prime number that is smaller than K. 
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