Proof of P-K formula Suppose customer i arrives to the system and finds N,customers waiting in queue Up to one customer receiving service And also define: -R,:the residual service time seen by i -W,:the waiting time in queue of customer i X Customer i arrives Xi-1 Xi-2 X3X.4 N,=3 Weigiang Sun Communication Networks 5Weiqiang Sun Communication Networks Proof of P-K formula • Suppose customer i arrives to the system and finds – Ni customers waiting in queue – Up to one customer receiving service • And also define: – Ri : the residual service time seen by i – Wi : the waiting time in queue of customer i 5 Customer i arrives Xi-1 Xi-2 Xi-3 Xi Xi-4 Ni =3