The basic orthogonal function for the kth subcarrier is defined as (,k)=exp(2n/)0≤t<T, Ig(t, k)=O, otherwise The basic functions satisfies the condition of orthogonality g(t,k)·g(t,p)dt=0,k≠p, T (t,k).g(t, p)dt=lg(t, k) dt=T, k=p( )    = =   ( , ) 0, . ( , ) exp 2 , 0 , g t k otherwise g t k j f k t t T       = = =  =     T T T g t k g t p dt g t k dt T k p g t k g t p dt k p 0 2 0 * 0 * ( , ) ( , ) ( , ) , . ( , ) ( , ) 0, , The basic orthogonal function for the kth subcarrier is defined as The basic functions satisfies the condition of orthogonality